JP2021063458A - Exhaust emission control device and control method for said exhaust emission control device - Google Patents

Abstract

To provide an exhaust emission control device provided in a cooling water circulation system of an internal combustion engine and capable of determining whether an auxiliary pump driven by electric power to cool a reducing agent addition valve is in an operable state.SOLUTION: A control device (40) for an exhaust emission control device includes: an acquisition section (41) acquiring starting-related information that can determine that an internal combustion engine (1) is started when the internal combustion engine (1) is started; and an execution section (42) executing control of an operation diagnosis for making a diagnosis to determine whether an auxiliary pump (34) is in an operable state. When the starting-related information is acquired by the acquisition section (41), the execution section (42) executes the control of the operation diagnosis while executing control of test driving for driving the auxiliary pump (34) at least over a predetermined period.SELECTED DRAWING: Figure 3

Description

The present invention relates to an exhaust purification device that purifies the exhaust gas of an internal combustion engine and a control method for the exhaust purification device.

Conventionally, as an exhaust purification device for a vehicle, for example, an SCR catalyst which is arranged in an exhaust passage of an internal combustion engine such as a diesel engine for a vehicle to adsorb ammonia (NH3) and reduce nitrogen oxides (NOx). A reducing agent addition valve that adds a reducing agent (for example, an aqueous urea solution (urea water)) into the exhaust passage on the upstream side of the SCR catalyst to supply NH3, and a reducing agent that is supplied from the storage tank to the reducing agent addition valve. There is a urea SCR system equipped with a reducing agent supply device and the like. In such a urea SCR system, for example, a cooling device is provided for cooling the reducing agent addition valve by circulating the cooling water of the internal combustion engine by a pump driven by the driving force of the internal combustion engine or an electric pump driven by electric power. There is a configuration that suppresses an increase in the temperature of the reducing agent addition valve exposed to high-temperature exhaust gas and the temperature of the reducing agent in the reducing agent addition valve (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-80397

In the exhaust gas purification device described in Patent Document 1, the driving of the pump driven by the driving force of the internal combustion engine is stopped when the internal combustion engine is stopped, but the electric pump is driven after the internal combustion engine is stopped. As a result, the cooling water of the internal combustion engine is circulated to cool the reducing agent addition valve. However, even if the electric pump is not in an operable state, for example, if the wiring of the electric pump is short-circuited or disconnected, or if the electric pump has a failure, the electric pump is after the internal combustion engine is stopped. It is not detected that the electric pump is not in an operable state until the operation of the electric pump, and the electric pump does not operate when the reducing agent addition valve is cooled after the internal combustion engine is stopped, and the reducing agent addition valve is cooled. There is a risk that it will not be done.

The present invention has been made against the background of the above-mentioned problems, and whether or not an auxiliary pump provided in the cooling water circulation system of the internal combustion engine and driven by electric power to cool the reducing agent addition valve can be operated. It is an object of the present invention to provide an exhaust gas purification device capable of determining.

The exhaust purification device according to the present invention includes an exhaust purification catalyst (12) that purifies the exhaust gas of the internal combustion engine (1) and a reducing agent addition valve (11) that adds a reducing agent to the upstream side of the exhaust purification catalyst (12). ), And a cooling device (30) that circulates the cooling medium of the internal combustion engine (1) to cool the reducing agent addition valve (11), and is an exhaust gas purification device (10). The control device (40) for controlling (10) and the cooling device (30) are provided and are driven by the driving force of the internal combustion engine (1) when the internal combustion engine (1) is in operation. When the main pump (33) that circulates the cooling medium and the internal combustion engine (1) provided in the cooling device (30) are stopped, electric power is applied regardless of the driving force of the internal combustion engine (1). The control device (40) includes an auxiliary pump (34) driven by the engine to circulate the cooling medium, and the internal combustion engine (1) is started when the internal combustion engine (1) is started. An acquisition unit (41) that acquires start-related information that can identify the fact, and an execution unit (42) that controls operation diagnosis for diagnosing whether or not the auxiliary pump (34) is in an operable state. When the start-related information is acquired by the acquisition unit (41), the execution unit (42) executes a test drive control for driving the auxiliary pump (34) for at least a predetermined period of time. At the same time, it is configured to execute the control of the operation diagnosis.

According to such a configuration, the control device (40) of the exhaust gas purification device (10) is the execution unit (40) when the start-related information is acquired by the acquisition unit (41), that is, when the internal combustion engine is started. Since the control of the test drive of the auxiliary pump (34) is executed by the auxiliary pump (34) and the control of the operation diagnosis of the auxiliary pump (34) is executed, the internal combustion engine (1) is stopped and the main pump (33) is driven. It is possible to diagnose whether or not the auxiliary pump (34) is in an operable state before the auxiliary pump (34) is operated to circulate the cooling medium after the stop.

The control method of the exhaust purification device according to the present invention is to add an exhaust purification catalyst (12) that purifies the exhaust gas of the internal combustion engine (1) and a reducing agent that adds a reducing agent to the upstream side of the exhaust purification catalyst (12). An exhaust gas purification device (10) including a valve (11) and a cooling device (30) that circulates a cooling medium of the internal combustion engine (1) to cool the reducing agent addition valve (11). When the control device (40) for controlling the exhaust gas purification device (10) and the internal combustion engine (1) provided in the cooling device (30) are being operated, the driving force of the internal combustion engine (1) is used. When the main pump (33) that is driven to circulate the cooling medium and the internal combustion engine (1) provided in the cooling device (30) are stopped, the driving force of the internal combustion engine (1) is applied. It is a control method of an exhaust gas purification device (10) including an auxiliary pump (34) that is driven by electric power to circulate the cooling medium, and the internal combustion engine (1) is started when the internal combustion engine (1) is started. Execution of acquisition step of acquiring start-related information that can identify that the engine (1) is started, and control of operation diagnosis for diagnosing whether or not the auxiliary pump (34) is in an operable state. The control device (40) includes a step, and executes a control for test-driving the auxiliary pump (34) for at least a predetermined period of time when the start-related information is acquired by the acquisition step in the execution step. At the same time, it is configured to execute the control of the operation diagnosis.

According to such a configuration, in the control method of the exhaust gas purification device (10), when the start-related information is acquired in the acquisition step, that is, when the internal combustion engine (1) is started, the auxiliary pump ( Since the control of the operation diagnosis of the auxiliary pump (34) is executed while the control of the test drive of 34) is executed, the cooling is performed after the internal combustion engine (1) is stopped and the drive of the main pump (33) is stopped. Before activating the auxiliary pump (34) to circulate the medium, it is possible to diagnose whether the auxiliary pump (34) is in an operable state.

The present invention may have only the invention-specific matters described in the claims of the present invention, and has a configuration other than the invention-specific matters together with the invention-specific matters described in the claims of the present invention. It may be a thing.

It is a figure for demonstrating the exhaust gas purification apparatus which concerns on embodiment. It is a figure for demonstrating operation diagnosis of an auxiliary pump. It is a flow chart for demonstrating the control method of an exhaust gas purification apparatus.

Hereinafter, an example of an embodiment of the exhaust gas purification device and the control method of the exhaust gas purification device according to the present invention will be described with reference to the drawings. The configuration, operation, and the like of the embodiments described below are examples, and the present invention is not limited to such configurations, operations, and the like. Further, in the following, the same or similar description will be simplified or omitted as appropriate. Further, in each figure, the same or similar members or parts are omitted or given the same reference numerals. Further, for the detailed structure, the illustration is appropriately simplified or omitted.

The exhaust purification device according to the present embodiment can be applied as a urea SCR system that purifies nitrogen oxides (NOx) in the exhaust gas of an internal combustion engine (for example, a diesel engine, a gasoline engine, etc.). In the present embodiment, a diesel engine for a vehicle will be described as an example of an internal combustion engine, but the present invention is not particularly limited thereto, and for example, an exhaust gas purification device for an internal combustion engine used in a construction machine, a generator, or the like. Can be applied as.

<Embodiment>
[Exhaust system of internal combustion engine]
The exhaust system of the internal combustion engine 1 according to the present embodiment will be described with reference to FIG. The internal combustion engine 1 according to the present embodiment is a diesel engine mounted on a vehicle.

As shown in FIG. 1, an exhaust pipe 2 is connected to the exhaust system of the internal combustion engine 1, and the exhaust pipe 2 is supplied into the exhaust pipe 2 by post injection or the like in the internal combustion engine 1. An oxidation catalyst 3 is provided which causes an oxidation reaction of the unburned fuel to generate heat of oxidation. As the oxidation catalyst 3, a known catalyst, for example, one in which platinum is supported on alumina and a predetermined amount of a rare earth element such as cerium is added can be used.

A diesel particulate filter 4 (hereinafter, may be referred to as a DPF: Diesel particulate filter) that collects particulate matter (PM) in the exhaust gas is provided on the downstream side of the oxidation catalyst 3. The exhaust gas flowing into the DPF 4 is heated by the heat of oxidation generated by the oxidation catalyst on the upstream side of the DPF 4, so that the DPF 4 can be heated. As DPF4, a known one, for example, a filter having a honeycomb structure made of a ceramic material or the like can be used.

On the downstream side of the DPF 4, a reducing agent addition valve 11 that adds a reducing agent into the exhaust pipe 2, an exhaust purification catalyst that adsorbs ammonia (NH3) and selectively purifies nitrogen oxides (NOx) in the exhaust gas. 12 (hereinafter, SCR catalyst: Selective Catalytic Reducation Catalyst may be referred to as) is provided. Since the DPF4 is provided on the upstream side of the SCR catalyst 12, there is no risk of PM adhering to the SCR catalyst 12. As the SCR catalyst 12, for example, a zeolite-based reduction catalyst having an adsorption function for NH3 and capable of selectively reducing NOX can be used.

Further, in the exhaust pipe 2, a NOx concentration sensor 13 for detecting the NOx concentration in the exhaust gas between the DPF 4 and the reducing agent addition valve 11, and an exhaust gas between the reducing agent addition valve 11 and the SCR catalyst 12 The temperature sensor 14 that detects the temperature, the temperature sensor 15 that detects the temperature of the exhaust gas on the downstream side of the SCR catalyst 12, and the NOx concentration sensor 16 that detects the NOx concentration in the exhaust gas on the downstream side of the SCR catalyst 12 exhaust the exhaust gas, respectively. It is arranged at a predetermined position in the pipe 2.

The control device 5 of the internal combustion engine 1 (hereinafter, may be referred to as an Engine Control Unit) is composed of a microcomputer, a microprocessor unit, and the like. The ECU 5 can control the DPF regeneration process in which the PM deposited on the DPF 4 is forcibly burned to regenerate the DPF 4. As the DPF regeneration process, for example, post-injection control for supplying unburned fuel into the exhaust pipe 2 from a fuel injection valve (not shown) of the internal combustion engine 1 is performed. By performing post-injection control, unburned fuel is supplied to the oxidation catalyst 3, and heat of oxidation is generated by the oxidation reaction of the unburned fuel to raise the temperature of the exhaust gas. Then, the temperature of the DPF4 is raised to about 500 ° C. to 600 ° C. by the heated exhaust gas, and the PM accumulated in the DPF4 is burned.

In the oxidation catalyst 3, after the unburned fuel is supplied by the post-injection control, heat of oxidation continues to be generated until all the supplied unburned fuels have completed the oxidation reaction. Therefore, the unburned fuel supplied by the post-injection control The temperature of the exhaust gas will continue to rise for a period corresponding to the amount. Further, even after the oxidation reaction of the unburned fuel is completed, the temperature of the exhaust gas will continue to rise for a period until the oxidation catalyst 3 drops to a predetermined temperature due to heat dissipation from the oxidation catalyst 3 to the exhaust gas. .. Then, during the period in which the exhaust gas is raised to a temperature higher than a predetermined temperature at which PM can be burned due to an oxidation reaction in the oxidation catalyst 3, it is generated when the PM accumulated in DPF 4 is burned. The heat of combustion causes the exhaust gas to continue to rise in temperature. As a result, when the post-injection control is performed and the DPF4 regeneration process is performed, the reducing agent addition valve 11 on the downstream side of the DPF4 has a period corresponding to the amount of unburned fuel supplied by the post-injection control. , May be exposed to higher temperature exhaust gas than during the period when the DPF regeneration process is not performed.

The DPF regeneration process is not limited to the example of post-injection control in the upper technique, and the temperature of the exhaust gas flowing into the DPF 4 is set to a temperature at which PM deposited on the DPF 4 can be burned (for example, 500 ° C. to 600 ° C.) Any configuration may be used as long as the temperature can be raised to about ° C.). For example, the DPF regeneration process may be performed by using a device that supplies unburned fuel to the oxidation catalyst 3 without relying on post-injection. Further, the PF regeneration process may be performed by directly heating the DPF 4 using a heating device such as a burner or a heating wire.

[About the exhaust purification device]
The exhaust gas purification device 10 of the internal combustion engine 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. The exhaust purification device 10 is a device that purifies NOx in the exhaust gas discharged from the internal combustion engine 1, and is configured as a urea SCR system that purifies NOx by using the above-mentioned SCR catalyst 12 and a reducing agent.

As shown in FIG. 1, the exhaust purification device 10 includes a reducing agent supply device 20 including the above-mentioned SCR catalyst 12, NOx concentration sensors 13 and 16, temperature sensors 14 and 15, and a reducing agent addition valve 11, and cooling of the internal combustion engine 1. A cooling device 30 that circulates a medium (hydrogen) to cool the reducing agent addition valve 11, a control device 40 that controls an exhaust purification device 10 (hereinafter, may be referred to as a DCU: Dosing Control Unit), a warning light, and a speaker. It is composed of a notification device 50 or the like provided with (not shown) and performing a predetermined notification.

The reducing agent supply device 20 includes a reducing agent addition valve 11 that adds a reducing agent into the exhaust pipe 2 on the upstream side of the SCR catalyst 12, a storage tank 21 that stores a urea aqueous solution (urea water) as a reducing agent, and the same. A reducing agent passage 22 (22a to 22c) for supplying the reducing agent in the storage tank 21 to the reducing agent addition valve 11, a pressure feeding pump 23 provided in the reducing agent passage 22 for pumping the reducing agent, and a reducing agent passage 22. It is provided with a reverting valve 24 or the like having a function of switching the inner reducing agent flow path.

The reducing agent passage 22 includes a first reducing agent passage 22a connecting the storage tank 21 and the pressure feeding pump 23, a second reducing agent passage 22b connecting the pressure feeding pump 23 and the reducing agent addition valve 11, and a second reducing agent passage. It includes a third reducing agent passage 22c that connects the 22b and the storage tank 21. Further, in the first reducing agent passage 22a, the reducing agent flow path is switched between the forward direction from the storage tank 21 to the reducing agent addition valve 11 and the reverse direction from the reducing agent addition valve 11 to the storage tank 21. A reverting valve 24 having a function is provided, a pressure sensor 25 for detecting the pressure in the second reducing agent passage 22b is provided in the second reducing agent passage 22b, and the third reducing agent passage 22c is provided with a pressure sensor 25. An orifice 26 is provided.

The reducing agent addition valve 11 is an ON-OFF valve that is controlled to an open state (ON state) or a closed state (OFF state) by a control signal output from the DCU 40, and reduces when the reducing agent addition valve 11 is controlled to the open state. While the agent is injected into the exhaust pipe 2 and added, the reducing agent is not added into the exhaust pipe 2 when the closed state is controlled. The reducing agent addition valve 11 is controlled by, for example, duty by the DCU 40, and the period of opening and the period of closing are controlled to predetermined lengths, so that a predetermined amount of reducing agent can be applied at a predetermined timing. It can be added into the exhaust pipe 2.

The electronic parts and resin parts constituting the reducing agent addition valve 11 are relatively sensitive to heat, and the heat resistant temperature Trim is about 140 ° C. to 150 ° C., while the exhaust gas temperature during normal operation of the internal combustion engine 1 is 200. It is about ° C. to 300 ° C. The exhaust gas purification device 10 includes a cooling device 30 that circulates the cooling medium of the internal combustion engine 1 to cool the reducing agent addition valve 11.

The cooling device 30 is a device that cools the reducing agent addition valve 11 by using the refrigerant of the internal combustion engine 1. As shown in FIG. 1, the cooling device 30 includes a water jacket 31, a refrigerant passage 32 (32a to 32d), a main pump 33, an auxiliary pump 34, a flow rate control valve 35, and the like.

The water jacket 31 is formed in a shape that covers the nozzle portion to which the reducing agent is added in the reducing agent addition valve 11, so that the reducing agent addition valve 11 can be inserted into the water jacket 31. .. Further, the water jacket 31 is provided with a refrigerant introduction port 31a and a refrigerant discharge port 31b, and a refrigerant passage (not shown) communicating from the refrigerant introduction port 31a to the refrigerant discharge port 31b is formed. The refrigerant supplied to the introduction port 31a flows through the refrigerant passage and is discharged from the refrigerant discharge port 31b. As the refrigerant flows inside the water jacket 31, relatively heat-sensitive members such as electronic parts (for example, an electromagnetic solenoid), a resin cover, and a nozzle portion of the reducing agent addition valve 11 inserted in the water jacket 31 are formed. It is cooled.

The refrigerant introduction port 31a and the refrigerant discharge port 31b of the water jacket 31 are connected to the refrigerant passage 32, respectively. The refrigerant passage 32 includes a first refrigerant passage 32a that connects the refrigerant introduction port 31a and the auxiliary pump 34, a second refrigerant passage 32b that connects the auxiliary pump 34 and the main pump 33, and a main pump 33 and the refrigerant discharge port 31b. Includes a third refrigerant passage 32c for connecting the above, and a fourth refrigerant passage 32d for connecting the branch portions provided in the second refrigerant passage 32b and the third refrigerant passage 32c via the flow control valve 35. Of the second refrigerant passage 32b and the third refrigerant passage 32c, the refrigerant passage in the peripheral portion of the main pump 33 is cooled in the refrigerant passage 32 by the cooling device (for example, fan, radiator, etc.) of the internal combustion engine 1. Refrigerant is cooled to a predetermined temperature.

The main pump 33 is a pump driven by the driving force of the internal combustion engine 1, is driven when the internal combustion engine 1 is in an operating state, and is stopped when the operation of the internal combustion engine 1 is stopped. The auxiliary pump 34 is an electric pump driven by electric power supplied from a battery (not shown) or the like provided in a vehicle on which the internal combustion engine 1 is mounted, and is driven independently of the operating state of the internal combustion engine 1. It is possible. The auxiliary pump 34 is appropriately controlled into an operating state and a stopped state by the DCU 40 described later. By controlling at least one of the main pump 33 and the auxiliary pump 34 to the operating state, the refrigerant is sent from the internal combustion engine 1 side to the refrigerant introduction port 31a of the water jacket 31 via the first refrigerant passage 32a and the second refrigerant passage 32b. The refrigerant supplied and discharged from the refrigerant discharge port 31b of the water jacket 31 can be circulated so as to return to the internal combustion engine 1 side via the third refrigerant passage 32c.

The flow rate control valve 35 is an on-off valve that is controlled to an open state and a closed state based on a control signal output from the DCU 40. When the flow control valve 35 is in the open state, at least one of the main pump 33 and the auxiliary pump 34 is driven so that the refrigerant flows through the fourth refrigerant passage 32d, while the flow control valve 35 is in the closed state. At one point, the refrigerant does not flow into the fourth refrigerant passage 32d. Regardless of whether the flow control valve 35 is in the open state or the closed state, the reducing agent in the refrigerant passage 32 is released by driving the main pump 33 or the auxiliary pump 34 in the first to third refrigerant passages. It is circulated through 32a to 32c.

The cooling device 30 according to the present embodiment includes a water jacket 31 in which a refrigerant passage is formed, and the reducing agent addition valve 11 is cooled by the refrigerant flowing through the refrigerant passage. A radiator fin may be provided together with the refrigerant passage, and the reducing agent addition valve 11 may be cooled by the cooling effect of the refrigerant flowing through the refrigerant passage and the cooling effect of the heat radiation from the heat radiation fins. In the configuration in which the reducing agent addition valve 11 is cooled by the refrigerant and the heat radiation fins, the nozzle portion exposed to a particularly high temperature can be effectively cooled.

The DCU 40 is composed of a microcomputer, a microprocessor unit, and the like, and as shown in FIG. 1, for example, executes control of the exhaust gas purification device 10 and acquisition unit 41 for acquiring information and the like regarding control of the exhaust gas purification device 10. It includes an execution unit 42 and a storage unit 43 that stores information used in various controls in the execution unit 42. The DCU 40 is energized and started to operate when the switch 7 described later is operated when the operation of the internal combustion engine 1 is started, and the switch 7 is turned on when the operation of the internal combustion engine 1 is stopped. The operation is stopped as it is operated. A part or all of the DCU 40 may be composed of an updatable firmware or the like, or may be composed of a program module or the like executed by a command from the CPU or the like. Further, the DCU 40 may be, for example, one or may be divided into a plurality of DCU 40s. Further, in the present embodiment, the DCU 40 and the ECU 5 are configured by different control devices, but the DCU 40 and the ECU 5 may be configured by the same control device.

The DCU 40 includes, for example, various sensors (NOx concentration sensors 13, 16, temperature sensors 14, 15, pressure sensors 25, etc.) included in the exhaust purification device 10 described above, and a vehicle CAN 6 (Controller Area) equipped with the exhaust purification device 10. Network), a switch 7 operated by a driver or the like when starting the operation of the internal combustion engine 1 and when stopping the operation of the internal combustion engine 1 (for example, when starting or stopping the operation of the internal combustion engine 1). A button switch to be operated, a so-called key switch to be rotated by inserting a predetermined key, etc.) are connected, and the acquisition unit 41 is connected to information output by various sensors, information existing on CAN 6, and a switch 7. It is possible to acquire information indicating the operation status of the above and output the acquired information to the execution unit 42 and the storage unit 43.

An ECU 5 or the like is connected to the CAN 6, and the acquisition unit 41 of the DCU 40 can acquire information or the like related to the control of the internal combustion engine 1 by communicating with the ECU 5 via the CAN 6. The information related to the control of the internal combustion engine 1 includes, for example, information on the fuel injection amount and injection timing, various sensors included in the internal combustion engine 1 (for example, a rotation speed sensor for detecting the rotation speed Ne of the internal combustion engine, and a vehicle speed of the vehicle. Information detected by a vehicle speed sensor, an accelerator sensor that detects the operation amount of the accelerator pedal, a brake sensor that detects the operation amount of the brake pedal, etc.) is included.

Further, for example, various devices (reducing agent addition valve 11, pressure feed pump 23, reverting valve 24, auxiliary pump 34, flow rate control valve 35, etc.) included in the above-mentioned exhaust purification device 10 are connected to the DCU 40. , The execution unit 42 can control the operation of various devices and output various information on the CAN 6 or to the storage unit 43. The execution unit 42 controls the operation of various devices, for example, opening / closing control for opening / closing the reducing agent addition valve 11, pressure feeding pump 23 for pumping the reducing agent into the reducing agent addition valve 11 and the reducing agent passage 22. Pressure feeding control for driving the auxiliary pump 34, cooling control for driving the auxiliary pump 34 to circulate the refrigerant in the refrigerant passage 32, and the like are performed.

As shown in FIG. 2, a FET 44 (Field Effect Transistor) is provided inside the DCU 40. A control signal is output to the gate G of the FET 44 based on the control of the execution unit 42, and a control signal for controlling the driving state of the auxiliary pump 34 is input, depending on the input status of the control signal. The space between the source S and the drain D of the FET 44 is controlled to be in an energized state or a non-energized state. The source S of the FET 44 is connected to the ground Gd and is grounded. The drain D of the FET 44 is connected to a predetermined power source (not shown), and a reference voltage Vr having a predetermined voltage value is applied. Further, the drain D is connected to a terminal 40a to which an external device of the DCU 40 is connected.

The negative electrode side of the electrical wiring (power supply wiring) for driving the auxiliary pump 34 described above is connected to the terminal 40a. The positive electrode side of the electrical wiring (power supply wiring) of the auxiliary pump 34 is connected to the terminal 40b to which the external device of the DCU 40 is connected, and the vehicle on which the exhaust purification device 10 is mounted via the circuit inside the DCU 40. The battery voltage Vba of a predetermined voltage value is applied by the battery connected to the positive electrode side of the battery (not shown).

The execution unit 42 can control the auxiliary pump 34 to the drive state by outputting a control signal to the gate G of the FET 44 and controlling between the source S and the drain D of the FET 44 to be in the energized state. By controlling the space between the source S and the drain D of the FET 44 in a non-energized state, the auxiliary pump 34 can be controlled in a stopped state.

In the present embodiment, the electrical wiring of the auxiliary pump 34 is connected to the terminal 40a of the DCU 40, but the auxiliary pump 34 may be connected to the terminal 40a via a reeley or the like. It may be configured to be directly connected to the terminal 40a without using it.

Further, in the present embodiment, the DCU 40 starts and stops according to the output status of the switch 7 operated by the driver or the like when the operation of the internal combustion engine 1 is started and when the operation of the internal combustion engine 1 is stopped. The DCU40 is started and stopped according to the configuration, that is, the output status of the switch common to the switch for starting and stopping the internal combustion engine 1, but the DCU40 is different from the switch for starting and stopping the internal combustion engine 1. A configuration may be configured in which predetermined switches are provided and the DCU 40 is started to be energized to start or stop the operation based on the output status of the switches.

[About the operation of DCU]
The control of the exhaust gas purification device 10 performed by the DCU 40 according to the present embodiment will be described. When the operation of the DCU 40 is started as the switch 7 is operated, the DCU 40 first executes initial processing such as initializing a predetermined storage area in the storage unit 43 and setting a predetermined initial value. .. Then, after the initial treatment is completed, the execution unit 42 controls the exhaust purification device 10 (for example, the execution unit 42 adds a predetermined amount of the reducing agent into the exhaust pipe 2 based on various information acquired from the acquisition unit 41 and the like. An execution unit 42 for pumping the reducing agent into the reducing agent addition valve 11 and the reducing agent passage 22 based on opening / closing control for controlling the opening / closing state of the reducing agent addition valve 11, various information acquired from the acquisition unit 41, and the like. Collects the reducing agent inside the reducing agent addition valve 11 and the reducing agent passage 22 into the storage tank 21 based on the pressure feeding control that controls the driving state of the pressure feeding pump 23, various information acquired from the acquisition unit 41, and the like. The execution unit 42 circulates in the refrigerant passage 32 based on the recovery control that controls the driving state of the pump 23 and the switching state of the reducing agent flow path by the reverting valve 24, various information acquired from the acquisition unit 41, and the like. The execution unit 42 controls the open / closed state of the flow control valve 35 for on-off control to adjust the flow rate of the refrigerant, and the execution unit 42 drives and controls the auxiliary pump 34 to control the refrigerant of the internal combustion engine 1 in the refrigerant passage 32. It is possible to perform cooling auxiliary control, etc. to circulate.

In the open / close control, the execution unit 42 adds to the exhaust pipe 2 based on the information acquired by the acquisition unit 41 (for example, the NOx concentration information output by the NOx concentration sensor 16, the rotation speed Ne of the internal combustion engine 1, etc.). Calculate the amount of reducing agent added. Then, the control of opening and closing the reducing agent addition valve 11 is executed according to the calculated addition amount. In the open / close control, in order to add the calculated amount of the reducing agent, for example, DUTY control for controlling the reducing agent addition valve 11 to the open state and the closed state at a predetermined time interval according to the addition amount of the reducing agent is performed. By doing so, a predetermined amount of reducing agent is added at a predetermined timing. By executing the opening / closing control, a predetermined amount of the reducing agent is added to the exhaust pipe 2 from the reducing agent addition valve 11 at a predetermined timing, and NH3 is supplied to the SCR catalyst 12.

In the pumping control, the execution unit 42 receives information acquired by the acquisition unit 41 (for example, information indicating that the switch 7 has been operated to start the operation of the internal combustion engine 1, information indicating that the switch 7 has been operated, the rotation speed Ne of the internal combustion engine 1, etc.). When it is specified that the internal combustion engine 1 is in operation, the pressure feeding pump 23 is driven so as to maintain the pressure in the second reducing agent passage 22b at a predetermined value. By executing the pressure feeding control, the reducing agent is filled in the reducing agent addition valve 11 and the reducing agent passage 22, and the reducing agent can be added from the reducing agent addition valve 11.

In the recovery control, the execution unit 42 is based on the information acquired by the acquisition unit 41 (for example, information indicating that the switch for ending the operation of the internal combustion engine 1 has been operated, the rotation speed Ne of the internal combustion engine 1, etc.). When it is specified that the operation of the internal combustion engine 1 is stopped, the driving state of the pressure feed pump 23 and the switching state of the reducing agent flow path by the reverting valve 24 are controlled to control the reducing agent addition valve 11 and the reducing agent passage. Control is performed so that the reducing agent inside 22 is collected in the storage tank 21. By executing the recovery control, it is possible to prevent the reducing agent from solidifying inside the reducing agent addition valve 11 and the reducing agent passage 22 and clogging the flow path.

In the on-off control, the execution unit 42 may freeze the reducing agent in the storage tank 21 based on the information acquired by the acquisition unit 41 (for example, the outside air temperature acquired via the CAN 6). Judge whether or not. For example, the outside air temperature acquired via CAN 6 is compared with a predetermined reference temperature (for example, a temperature higher than the freezing point of the reducing agent by a predetermined value), and the reducing agent in the storage tank 21 may freeze. When it is determined that there is, a control signal for controlling the open state is output to the flow control valve 35 to control the state in which the refrigerant flows through the fourth refrigerant passage 32d. As a result, the reducing agent in the storage tank 21 can be heated by the refrigerant, and the reducing agent in the storage tank 21 freezes, or the reducing agent addition valve 11 due to volume expansion due to the freezing of the reducing agent, It prevents the storage tank 21, the reducing agent passage 22, the main pump 33, the auxiliary pump 34, and the like from being damaged. Further, in the on-off control, the execution unit 42 in the storage tank 21 based on the information acquired by the acquisition unit 41 (for example, the temperature of the storage tank 21, the temperature of the reducing agent in the storage tank 21, etc.). Determine if the reducing agent may be frozen. For example, the temperature of the reducing agent in the storage tank 21 is compared with a predetermined reference temperature (for example, the temperature of the freezing point of the reducing agent), and the reducing agent in the storage tank 21 may be frozen. When it is determined, a control signal for controlling the open state is output to the flow control valve 35 to control the state in which the refrigerant flows through the fourth refrigerant passage 32d. As a result, the reducing agent in the storage tank 21 is heated by the refrigerant and thawed.

The flow rate control valve 35 may be configured by a flow rate adjusting valve capable of adjusting the flow rate of the refrigerant flowing through the fourth refrigerant passage 32d by controlling the opening degree by the DCU 40. In the configuration in which the flow control valve 35 is a flow control valve, the DCU 40 responds to predetermined information acquired by various sensors (for example, the rotation speed Ne of the internal combustion engine 1, the temperature information output by the temperature sensor 14, etc.). By controlling the opening degree of the flow control valve, the flow rate of the refrigerant circulated in the refrigerant passage 32 can be appropriately controlled to control the reducing agent addition valve 11 and the reducing agent in the reducing agent addition valve 11. The temperature is controlled within a predetermined range (for example, the temperature of the reducing agent addition valve 11 is about 70 ° C. to 80 ° C. lower than the heat resistant temperature Tim) to prevent the temperature of the reducing agent addition valve 11 from becoming higher than the heat resistant temperature Tim. it can.

In the cooling auxiliary control, as will be described later, in the execution unit 42, the drive of the main pump 33 is stopped based on the information acquired by the acquisition unit 41, so that the temperature of the reducing agent addition valve 11 becomes the heat resistant temperature Trim. When there is a possibility that the temperature will increase more than the above, the auxiliary pump 34 can be driven to continue the circulation of the refrigerant in the refrigerant passage 32 even after the operation of the internal combustion engine 1 is stopped, and the auxiliary pump 34 can be operated. Performs control to diagnose whether the condition is present or not.

[About cooling auxiliary processing]
The cooling assist control performed by the DCU 40 according to the present embodiment will be described with reference to FIG.

After it is specified that the switch 7 is operated and the operation of the internal combustion engine 1 is started based on the information acquired by the acquisition unit 41 (for example, the information output by the switch 7), the DCU 40 is operated by the switch 7. During the period until the operation of the internal combustion engine 1 is specified to be stopped (hereinafter, may be referred to as a unit period), the cooling auxiliary control is performed at predetermined time intervals (for example, 10 ms intervals, etc.). Is repeated.

As shown in FIG. 3, in the cooling auxiliary control, first, the acquisition unit 41 can specify the diagnosis result when the operation diagnosis for diagnosing whether or not the auxiliary pump 34 is in the operable state was performed last time. Acquire diagnostic information (S01). The diagnostic information is stored in the storage unit 43 by performing the operation diagnosis in the step of S07 described later. The storage area of the storage unit 43 in which the diagnostic information is stored is the period during which the DCU 40 is operating (from the time when the switch 7 is operated and the operation of the DCU 40 is started, the switch 7 is operated and the operation of the DCU 40 is stopped. The contents of the diagnostic information can be retained for a period of time (until the time). The storage area of the storage unit 43 in which the diagnostic information is stored is initialized when the operation of the DCU 40 is started by the above-mentioned initial processing, and as an initial value, the auxiliary pump 34 is in an operable state. The indicated value is set. The storage area of the storage unit 43 in which the diagnostic information is stored has a configuration capable of holding the contents of the diagnostic information during the period when the DCU 40 is not operating (for example, a configuration that is a non-volatile storage means such as a so-called ROM). Alternatively, the configuration may be such that the content of the diagnostic information is lost when the operation of the DCU 40 is stopped (for example, a configuration which is a volatile storage means such as a so-called RAM).

After the diagnostic information is acquired by the acquisition unit 41, the execution unit 42 determines, based on the diagnostic information, whether or not it was diagnosed in the previous operation diagnosis that the auxiliary pump 34 is not in an operable state (S02). ). Then, in the step of S02, when it is determined that the auxiliary pump 34 is not in an operable state (Y), the cooling auxiliary control is terminated.

On the other hand, in the step of S02, when it is determined that the auxiliary pump 34 is not in an operable state (N), the acquisition unit 41 controls the stop of the internal combustion engine 1 by the ECU 5. Stop-related information that can specify whether or not the internal combustion engine 1 is stopped (information that can specify that the operation of the internal combustion engine 1 is stopped when the switch 7 is operated to stop the operation of the internal combustion engine 1, the internal combustion engine 1 Information that can specify that control for temporarily stopping the operation (for example, so-called idling stop control, etc.) is performed, information such as the number of revolutions of the internal combustion engine 1 Ne, etc.) is acquired from the CAN 6, and the execution unit 42 is concerned. Based on the stop-related information, it is determined whether or not the ECU 5 controls to stop the operation of the internal combustion engine 1 (S04).

In the step of S04, when it is determined that the control for stopping the operation of the internal combustion engine 1 is not performed (N) (for example, when the operation control for operating the internal combustion engine 1 is continued, the operation of the internal combustion engine 1 is stopped. In the case where the state is continued, the acquisition unit 41 can specify whether or not the start control of the internal combustion engine 1 is performed by the ECU 5 (for example, the start control of the internal combustion engine 1 by the ECU 5). (S05), the flag information indicating that the operation is performed, the information that can identify that the switch 7 has been operated to start the operation of the internal combustion engine 1, and the like) are acquired from the CAN 6.

In the step of S05, the start-related information acquired by the acquisition unit 41 may be any information that can specify whether or not the start control of the internal combustion engine 1 is performed, and the start control of the internal combustion engine 1 is performed. Information that can be directly output by the ECU 5 so as to be able to specify whether or not it is possible, or information that can indirectly specify whether or not start control is performed (for example, it is controlled when the internal combustion engine 1 is started). Information indicating whether or not control for operating various devices such as a starter motor is performed, control signals of various devices such as the starter motor, etc.) may be used.

After the start-related information is acquired by the acquisition unit 41 in the step of S05, the execution unit 42 determines whether or not the start control of the internal combustion engine 1 is performed by the ECU 5 based on the start-related information (S06). When it is determined (Y) that the start control of the internal combustion engine 1 is performed in the step of S06, the acquisition unit 41 acquires the output information of the switch 7 (S07), and the execution unit 42 uses the output information and the like. Based on this, it is determined whether or not the switch 7 has been operated to start the operation of the internal combustion engine 1 (S08). Then, when it is specified that the switch 7 is operated to start the operation of the internal combustion engine 1 in the step S08 (Y), the start control of the internal combustion engine 1 is performed with the start of the operation of the internal combustion engine 1. That is, in the unit period from the start of the operation of the internal combustion engine 1 to the end of the operation, it is determined that it is the timing when the start control is first performed, and a predetermined predetermined period (for operation diagnosis) is determined. The test drive control for driving the auxiliary pump 34 is performed for a period sufficient for obtaining the diagnostic result (for example, 5 seconds) (S09).

In the test drive control, after initializing the predetermined timer A, the execution unit 42 starts the control of counting up the timer to measure the predetermined time, and outputs the control signal for driving the auxiliary pump 34 to the FET 44. The control to output to the gate G of is started. Then, the execution unit 42 sends a control signal to the FET 44 until it is specified that the above-mentioned predetermined period (a period sufficient for the diagnosis result to be acquired by the operation diagnosis) has elapsed based on the timer. The output control is continued, and when it is specified that the predetermined period has elapsed, the output of the control signal to the FET 44 is stopped. As described above, in the test drive control, when the start control of the internal combustion engine 1 is performed for the first time in the unit period, the gate G of the FET 44 extends for a predetermined period sufficient for obtaining the diagnosis result in the operation diagnosis. By outputting to, the auxiliary pump 34 is driven for the predetermined period.

After the test drive control is started in the step S09, that is, in the state where the auxiliary pump 34 is operated, the execution unit 42 controls the operation diagnosis control for performing the operation diagnosis (S10). Further, when the execution unit 42 determines that the start control of the internal combustion engine 1 is not performed in the step S06 (N), the start control of the internal combustion engine 1 is performed in the step S08, but the first in the unit period. When it is determined that the start control is not performed (N), that is, the operation diagnosis control is controlled even when the auxiliary pump 34 is not operated (S10).

In the operation diagnosis control, first, the execution unit 42 causes the acquisition unit 41 to acquire the DS voltage Vds between the drain D of the FET 44 and the source S. Then, the execution unit 42 determines whether or not the auxiliary pump 34 is being driven, for example, based on the output status of the control signal to the gate G of the FET 44. Then, when the auxiliary pump 34 is not being driven (for example, a period before the auxiliary pump 34 is driven by the above-mentioned test drive control or a period after the test drive control is completed (for example, the normal exhaust purification device 10). During the operation period), etc.), the value of the DS voltage Vds is compared with the predetermined first reference voltage value V_th1 and the second reference voltage value V_th2.

The first reference voltage value V_th1 is the drain D and source of the FET 44 in a ground short-circuited state (hereinafter, may be referred to as an SCG state) in which the external wiring connected to the terminal 40a is short-circuited to the ground Gd. It is set to a value slightly higher than the voltage drop value between S (for example, 2V or the like). The second reference voltage value V_th2 is a value higher than the above-mentioned first reference voltage value V_th1 and is in an open load state in which an electric load is not connected to the terminal 40a (for example, electricity of the auxiliary pump 34 which is an electric load). The drain D and the drain D of the FET 44 when the wiring is not connected to the terminal 40a, the electrical wiring between the terminal 40a and the auxiliary pump 34 is broken, etc., may be hereinafter referred to as an OL state). It is set to a value slightly lower than the voltage drop value between the sources S (for example, a value equal to or less than the reference voltage Vr described above).

Then, when the value of the DS voltage Vds is the first reference voltage value V_th1 or more and the second reference voltage value V_th2 or more, the execution unit 42 diagnoses that the auxiliary pump 34 is in an operable state. .. After that, when the state is continued for a predetermined time (for example, 500 msec), the storage unit 43 stores diagnostic information (OK) indicating that the auxiliary pump 34 is in an operable state, and the diagnosis is made. Information (OK) is output on CAN6. The battery voltage Vba is applied to the positive side of the electrical wiring (power supply wiring) of the auxiliary pump 34, the terminal 40a is connected to the negative side of the electrical wiring (power supply wiring) of the auxiliary pump 34, and the electrical wiring of the auxiliary pump 34. In the state where there is no disconnection or ground short circuit between the battery and the terminal 40a, the voltage value corresponding to the battery voltage Vba, that is, the voltage value larger than the first reference voltage value V_th1 and the second reference voltage value V_th2 is DS. Since it is acquired as the voltage Vds, it is determined as a diagnosis result that the auxiliary pump 34 is in an operable state.

On the other hand, when the value of the DS voltage Vds is less than the first reference voltage value V_th1, the execution unit 42 diagnoses that it is in the SCG state and the auxiliary pump 34 is not in the operable state. After that, when the state is continued for a predetermined time (for example, 500 msec), the storage unit 43 stores diagnostic information (NG_SCG) indicating that the auxiliary pump 34 is not in an operable state, and the diagnostic information is stored. (NG_SCG) is output on CAN6.

In the internal circuit of the DCU 40, the reference voltage Vr is applied to the drain D and the terminal 40a of the FET 44. However, when the SCG state is generated, the current generated by the application of the reference voltage Vr hardly flows between the drain D and the source S of the FET 44, and is more electric than the drain D and the source S of the FET 44. It flows to the ground Gd via the terminal 40a having low resistance and the external wiring, and the voltage drop value between the drain D and the source S of the FET 44 becomes a minute value (for example, about 0V to 2V). Therefore, by setting the first reference voltage value V_th1 to a value higher than the voltage drop value that can occur between the drain D and the source S of the FET 44 in the SCG state, the SCG state is set using the first reference voltage value V_th1. Can be determined.

Further, when the value of the DS voltage Vds is equal to or higher than the first reference voltage value V_th1 and less than the second reference voltage value V_th2, the execution unit 42 is in the OL state and the auxiliary pump 34 can be operated. Diagnose not. After that, when the state is continued for a predetermined time (for example, 500 msec), the storage unit 43 stores diagnostic information (NG_OL) indicating that the auxiliary pump 34 is not in an operable state, and the diagnostic information is stored. (NG_OL) is output on CAN6.

In the internal circuit of the DCU 40, the reference voltage Vr is applied to the drain D and the terminal 40a of the FET 44, but when the OL state is generated, the current generated by the application of the reference voltage Vr flows out of the terminal 40a. It does not flow, flows between the drain D and the source S of the FET 44, and flows to the ground Gd connected to the source S, so that a voltage drop corresponding to the reference voltage Vr occurs between the drain D and the source S of the FET 44. Therefore, the second reference voltage value V_th2 is a voltage drop value that can occur between the drain D and the source S of the FET 44 in the OL state, that is, a value lower than the value of the reference voltage Vr, and a value lower than the above-mentioned first reference voltage value V_th1. By setting a high value, the OL state can be determined using the second reference voltage value V_th2.

In the operation diagnosis control, when the auxiliary pump 34 is being driven, the value of the DS voltage Vds is compared with the predetermined third reference voltage value V_th3. The third reference voltage value V_th3 is the FET 44 when the electrical wiring of the auxiliary pump 34 is normally connected to the terminal 40a without disconnection or battery short circuit, and the auxiliary pump 34 is normally driven. It is set to a value slightly higher than the voltage drop value between the drain D and the source S of.

Then, when the value of the DS voltage Vds is less than the third reference voltage value V_th3, the execution unit 42 diagnoses that the auxiliary pump 34 is in an operable state. After that, when the state is continued for a predetermined time (for example, 500 msec), the storage unit 43 stores diagnostic information (OK) indicating that the auxiliary pump 34 is in an operable state, and the diagnosis is made. Information (OK) is output on CAN6.

On the other hand, when the value of the DS voltage Vds is equal to or higher than the third reference voltage value V_th3, the battery voltage Vba is applied to the terminal 40a without passing through the load to the terminal 40a, and the battery short-circuit state (hereinafter referred to as SCB state). In some cases, it is an overvoltage state (sometimes called an OV state) in which an abnormal overvoltage higher than the normal state is applied to the terminal 40a for some reason, and the auxiliary pump 34 is not in an operable state. To diagnose. After that, when the state is continued for a predetermined time (for example, 500 msec), diagnostic information (NG_SCB) indicating that the auxiliary pump 34 is not in an operable state is output to the storage unit 43 and stored. The diagnostic information (NG_SCB) is output on CAN6.

When the electrical wiring of the auxiliary pump 34 is normally connected to the terminal 40a without disconnection or short circuit of the battery, and the auxiliary pump 34 is normally driven, the battery voltage Vba is set to the auxiliary pump 34 and the auxiliary pump 34. Since the voltage is divided and applied between the drain D and the source S of the FET 44 according to the ratio of the respective electric resistance values, a voltage drop lower than the value of the battery voltage Vba occurs between the drain D and the source S of the FET 44. Occurs. On the other hand, when the SCB state is generated, the battery voltage Vba is applied between the drain D and the source S of the FET 44, so that a higher voltage drop occurs as compared with the normal state. Further, when the OV state is generated, a voltage having a higher value than that in the normal state is applied between the drain D and the source S of the FET 44, so that a higher voltage drop occurs as compared with the normal state. Become. Therefore, by setting the third reference voltage value V_th3 to a value slightly higher than the voltage drop value that can occur between the drain D and the source S of the FET 44 in the normal state, the third reference voltage value V_th3 is used. It can be determined that it is in the SCB state or the OV state.

After starting the operation diagnosis control in the step S10, the execution unit 42 has elapsed a predetermined period for driving the auxiliary pump 34 by the test drive control based on the value of the timer A started in the step S09 described above. If it is determined whether or not (S11) and it is determined that the predetermined period has not elapsed (N), the process returns to the step of S09, and the drive control and operation diagnosis control of the auxiliary pump 34 by the test drive control are performed. On the other hand, when it is determined that the predetermined period has elapsed (Y), the output of the control signal to the gate G of the FET 44 is stopped to control the operation of the auxiliary pump 34, and the timer A is stopped. The measurement for a predetermined period according to the above is completed (S12).

Then, the acquisition unit 41 acquires the diagnostic information stored in the storage unit 43 (S13), and the execution unit 42 is not in a state in which the auxiliary pump 34 can be operated based on the diagnostic information acquired by the acquisition unit 41. It is determined whether or not the fact has been diagnosed (S14). If it is determined in step S14 that the auxiliary pump 34 is not in an operable state (N), the cooling auxiliary control is terminated, but the auxiliary pump 34 is not in an operable state. When it is determined that the diagnosis is made (Y), the notification device 50 notifies that the auxiliary pump 34 is not in an operable state (S15).

In the notification control, the execution unit 42 outputs a control signal to the notification device 50 to notify that the auxiliary pump 34 is not in an operable state. By receiving the control signal from the execution unit 42, the notification device 50 controls, for example, a predetermined warning light (not shown) provided in the vehicle on which the notification device 50 is mounted to be in a lit state, and also controls the vehicle to be in a lit state. By controlling the output of a predetermined warning sound from a predetermined speaker (not shown) provided in the vehicle, the driver or the like of the vehicle is notified that the auxiliary pump is not in an operable state. In the notification device 50, the mode of notifying the driver of the vehicle that the auxiliary pump is not in an operable state may be only controlling the warning light to a lighting state or simply outputting a warning sound from the speaker. Alternatively, a notification means other than a warning light or a speaker may be used to notify that the auxiliary pump is not in an operable state.

The execution unit 42 starts the notification control by the step of S15, and then ends the cooling assist process. The notification device 50 is sufficient for a predetermined period (for example, the driver of the vehicle or the like to recognize that the warning light is in the lighting state) after controlling the warning light to be in the lighting state based on the control signal from the DCU 40. It is preferable that the warning light is kept lit for a period (a period until it is specified that there is no abnormality in the auxiliary pump 34).

When it is determined that the ECU 5 controls to stop the operation of the internal combustion engine 1 based on the stop-related information acquired from the CAN 6 in the step of S04 described above (Y) (for example, the operation of the internal combustion engine 1 is stopped). Therefore, when the operation of the internal combustion engine 1 is stopped as the switch 7 is operated, the operation of the internal combustion engine 1 is temporarily stopped (for example, so-called idling stop control). In such cases, the acquisition unit 41 determines the temperature information of the SCR catalyst 12 (for example, the temperature of the SCR catalyst 12 estimated based on the transition of the output information of the temperature sensors 14 and 15), the reducing agent addition valve. Temperature information about 11 (for example, the temperature around the reducing agent addition valve 11 specified based on the output information of the temperature sensor 14), control information about the internal combustion engine 1 acquired from the CAN 6 (for example, the regeneration process of the DPF 4). Information that can identify whether or not it is being implemented, information about fuel injection into the internal combustion engine 1, information indicating the elapsed time since the operation of the internal combustion engine 1 was stopped, etc.), etc. Acquire (S16). Then, based on the information acquired by the acquisition unit 41, the execution unit 42 causes heat damage to the reducing agent addition valve 11 (for example, damage is caused by exposure to a high temperature, and the reducing agent addition valve is solidified by the reducing agent. It is determined whether or not there is a possibility that the reducing agent passage in 11 is clogged (S17).

In the step of S17, when it is determined that the reducing agent addition valve 11 may be damaged by heat (Y), for example, the temperature of the SCR catalyst 12 is predetermined based on the temperature information of the SCR catalyst 12. If it is higher than a predetermined threshold, the temperature of the reducing agent addition valve 11 is higher than a predetermined threshold based on the temperature information about the reducing agent addition valve 11, and the DPF4 is regenerated based on the control information about the internal combustion engine 1. When the treatment is carried out and it is specified that the temperature of the reducing agent addition valve 11 on the downstream side of the oxidation catalyst 3 and the DPF 4 rises, the execution unit 42 drives the auxiliary pump 34. Auxiliary pump drive control is performed (S18). In the auxiliary pump drive control, the execution unit 42 continuously outputs a control signal for driving the auxiliary pump 34 to the gate G of the FET 44. By performing the auxiliary pump drive control, the execution unit 42 continues the circulation of the refrigerant of the internal combustion engine 1 by driving the auxiliary pump 34 regardless of the operating state of the internal combustion engine 1, and cools the reducing agent addition valve 11. can do.

After the auxiliary pump drive control is started in the step S18, the acquisition unit 41 obtains at least one of the temperature information of the SCR catalyst 12, the temperature information of the reducing agent addition valve 11, the control information of the internal combustion engine 1, and the like. Newly acquired (S19). Then, the execution unit 42 determines whether or not the reducing agent addition valve 11 is no longer in a state of heat damage based on the information acquired by the acquisition unit 41 (S20), and the reducing agent addition valve 11 is still heat-damaged. (N), the process returns to the step of S19, the auxiliary pump drive control is continued (S18 to S20), and it is determined that the reducing agent addition valve 11 is no longer in a situation where heat damage occurs. In the case (Y), the auxiliary pump drive control is terminated and the cooling auxiliary control is terminated.

[About the action and effect of the operation of the exhaust purification device]
The exhaust purification device 10 according to the present embodiment includes a reducing agent addition valve 11 for adding a reducing agent in the exhaust pipe 2 on the upstream side of the SCR catalyst 12, and the reducing agent addition valve 11 is, for example, a reducing agent. When the DPF regeneration process for regenerating the DPF 4 arranged on the upstream side of the addition valve 11 is performed by the ECU 5 of the internal combustion engine 1, it is exposed to a higher temperature exhaust gas than in the normal time when the DPF regeneration process is not performed. There are times.

On the other hand, the exhaust gas purification device 10 cools the reducing agent addition valve 11 by circulating the refrigerant of the internal combustion engine 1 by the main pump 33 driven by the driving force of the internal combustion engine 1 or the auxiliary pump 34 driven by the electric power. It is configured to include a cooling device 30 to be used. Then, the DCU 40, which is the control device of the exhaust gas purification device 10, uses the driving force of the internal combustion engine 1 to drive the main pump 33 during the period in which the internal combustion engine 1 is operating. The refrigerant of the engine 1 is circulated to cool the reducing agent addition valve 11. Further, the drive of the main pump 33 is stopped when the internal combustion engine 1 is stopped, but the operation of the internal combustion engine 1 is stopped after the stop, for example, when the DPF regeneration process is continued, the reducing agent. When the temperature of the addition valve 11 may be higher than the heat resistant temperature Tlim, the internal combustion engine 1 is operated by circulating the cooling water of the internal combustion engine 1 by driving and operating the auxiliary pump 34 with electric power. The reducing agent addition valve 11 can be cooled even after the engine is stopped.

However, when the auxiliary pump 34 is not in an operable state, for example, when the wiring of the auxiliary pump 34 is disconnected (OL state) or ground short-circuited state (SCG state), or when a failure occurs in the auxiliary pump 34 and the battery is used. Even when a short-circuit state (SCB state) or an overvoltage state (OV state) occurs, the auxiliary pump 34 can be operated until the auxiliary pump 34 is operated even after the internal combustion engine 1 is stopped. It is not detected that the state is not met, and when the reducing agent addition valve 11 is cooled after the internal combustion engine 1 is stopped, the auxiliary pump 34 may not operate and the reducing agent addition valve 11 may not be cooled. In particular, the auxiliary pump 34 is operated in the battery short-circuit state (SCB state) and the overvoltage state (OV state) of the auxiliary pump 34, which is difficult to detect unless the auxiliary pump 34 is controlled to the operating state. It may not be detected until time.

On the other hand, the DCU 40 according to the present embodiment can perform cooling auxiliary control for circulating the refrigerant of the internal combustion engine 1 by driving and controlling the auxiliary pump 34, and in the cooling auxiliary control, the execution unit of the DCU 40. 42 is a switch that is acquired and output by the acquisition unit 41 when it is determined that the start control for starting the operation of the internal combustion engine 1 is performed based on the start-related information acquired by the acquisition unit 41 (S06). Based on the output information of 7, the switch 7 is operated to start the operation of the internal combustion engine 1 for a unit period (after the operation of the switch 7 for starting the operation of the internal combustion engine 1 is performed, the relevant operation is performed. When it is determined that the start control is first performed in the period until the operation of the switch 7 for stopping the operation of the internal combustion engine 1 is performed (S08), the test drive control for driving the auxiliary pump 34 is performed. (S09), the operation diagnosis for diagnosing whether or not the auxiliary pump 34 is in an operable state is controlled (S10). As a result, the operation diagnosis can be performed when the start control is performed at the beginning of the unit period, and at the end of the unit period, that is, after the operation of the internal combustion engine 1 is stopped and the drive of the main pump 33 is stopped. Before operating the auxiliary pump 34, it is possible to diagnose whether or not the auxiliary pump 34 is in an operable state.

In the present embodiment, in the cooling assist control, the execution unit 42 determines that the start control for starting the operation of the internal combustion engine 1 is performed, and determines that the start control is performed first in the unit period. In addition, although it is configured to control the operation diagnosis while performing the test drive control, the execution unit 42 performs the test drive control at least when it is determined that the start control for starting the operation of the internal combustion engine 1 is performed. It may be configured to control the operation diagnosis. In such a configuration, not only when it is determined that the start control is first performed in the unit period, but also by performing test drive control and operation diagnosis control each time the internal combustion engine 1 is started, the internal combustion engine 1 It is possible to diagnose whether or not the auxiliary pump 34 is in an operable state before the auxiliary pump 34 is operated after the main pump 33 is stopped and the drive of the main pump 33 is stopped, so that the frequency of the diagnosis can be increased. Can be done.

Further, in the present embodiment, in the cooling assist control, the execution unit 42 controls the operation diagnosis while performing the test drive control when it is determined that the start control is first performed in the unit period. The execution unit 42 may be configured to control the operation diagnosis while performing test drive control at least once at any timing other than the timing at which the start control is first performed in the unit period. Even in such a configuration, similarly to the configuration according to the present embodiment, after the operation of the internal combustion engine 1 is stopped and the drive of the main pump 33 is stopped, the auxiliary pump 34 is operated before the auxiliary pump 34 is operated. Operation diagnosis can be performed.

Further, in the present embodiment, in the cooling auxiliary control, the acquisition unit 41 of the DCU 40 acquires the output information of the switch 7, and the execution unit 42 starts the operation of the internal combustion engine 1 based on the output information. When it is specified that the switch 7 has been operated, it is determined that the start control of the internal combustion engine 1 is performed when the operation of the internal combustion engine 1 is started. Information other than the above may be used to determine whether or not the start control of the internal combustion engine 1 is performed when the operation of the internal combustion engine 1 is started. For example, information regarding the control of the internal combustion engine 1 acquired from the CAN 6 ( For example, the internal combustion engine 1 is output based on information that can be output by the ECU 5 and can specify that the start control of the internal combustion engine 1 is performed when the operation of the internal combustion engine 1 is started, output information of the switch 7 output by the ECU 5, etc. It may be configured to determine whether or not the start control of the internal combustion engine 1 is performed with the start of the operation of the internal combustion engine 1.

When the execution unit 42 of the DCU 40 determines that the start control for starting the operation of the internal combustion engine 1 is performed (S06), the switch 7 for starting the operation of the internal combustion engine 1 is operated for a unit period (S06). When it is determined that the start control is first performed (S08) during the period from after that until the operation of the switch 7 for stopping the operation of the internal combustion engine 1 is performed), the test drive control is performed (S09). ), Since the operation diagnosis is controlled (S10), when the load for circulating the refrigerant is relatively large before the main pump 33 starts the circulation of the refrigerant during the unit period. , The operation diagnosis can be performed by performing the test drive control of the auxiliary pump 34. Further, during the unit period, for example, when the operation of the internal combustion engine 1 is frequently stopped and started by idling stop control or the like, test drive control is performed every time the internal combustion engine 1 is started. It is possible to prevent the auxiliary pump 34 from being operated, and it is possible to reduce the operation frequency of the auxiliary pump 34 and reduce the deterioration due to the operation.

When it is specified in the operation diagnosis that the auxiliary pump 34 is not in an operable state (S14), the execution unit 42 of the DCU 40 notifies the fact by the notification device 50 (S15). As a result, when the auxiliary pump 34 is not in an operable state, it is possible to urge repair or the like so that the auxiliary pump 34 is in an operable state.

Since the execution unit 42 of the DCU 40 outputs diagnostic information on the CAN 6 that can identify whether or not the auxiliary pump 34 is in an operable state as a diagnosis result in the control of the operation diagnosis, the vehicle on which the DCU 40 is mounted can be used. Various devices (for example, ECU 5 and the like) provided can refer to the diagnosis result of the auxiliary pump 34.

When it is determined that the start control is first performed in the unit period, the execution unit 42 of the DCU 40 controls the operation diagnosis while performing the test drive control of the auxiliary pump 34. That is, since the operation diagnosis is performed in the operating state in which the auxiliary pump 34 is driven, items that can be specified when the drive control of the auxiliary pump 34 is performed in the operation diagnosis, for example, a battery short circuit in the auxiliary pump 34. It is possible to identify whether or not a state (SCB state) or an overvoltage state (OV state) may have occurred. Then, when the execution unit 42 identifies the possibility that a battery short-circuit state (SCB state) or an overvoltage state (OV state) has occurred with respect to the auxiliary pump 34, the auxiliary pump 34 is not in an operable state. Can be diagnosed.

When the execution unit 42 of the DCU 40 determines that the start control for starting the operation of the internal combustion engine 1 is not performed (S06), and determines that the start control of the internal combustion engine 1 is not the first start control in the unit period (S06). S08), the test drive control is not performed, and the operation diagnosis is controlled. That is, since the operation diagnosis is performed in the operating state in which the auxiliary pump 34 is not driven, the matters that can be specified when the drive control of the auxiliary pump 34 is not performed in the operation diagnosis, for example, the auxiliary pump 34. It is possible to specify whether or not there is a possibility that a disconnection state, an open load state (OL state), a ground short circuit state (SCG state), or the like has occurred. Then, when the execution unit 42 identifies the possibility that the auxiliary pump 34 is in a disconnected state, an open load state (OL state), a ground short circuit state (SCG state), or the like, the auxiliary pump 34 can be operated. It is possible to diagnose that it is not in a state.

At the start of the cooling auxiliary control, the execution unit 42 of the DCU 40 determines whether or not the auxiliary pump 34 is in an operable state by referring to the diagnostic information set by the previous operation diagnosis (S02), and determines whether or not the auxiliary pump 34 is in an operable state (S02). If it is determined that is not in an operable state, the test drive control (S09) and the auxiliary pump drive control (S19) of the auxiliary pump 34 are not performed, and the cooling auxiliary control is terminated. As a result, the execution unit 42 does not output the control signal for driving the auxiliary pump 34 to the gate G of the FET 44 after it is determined in the operation diagnosis that the auxiliary pump 34 is not in an operable state (S10). It is possible to limit the energization of the auxiliary pump 34 to prevent the auxiliary pump 34 from being operated when the auxiliary pump 34 is not in an operable state.

In the present embodiment, in the cooling auxiliary control, when the execution unit 42 determines that the auxiliary pump 34 is not in an operable state, the test drive control (S09) and the auxiliary pump drive control (S19) of the auxiliary pump 34 are performed. By not performing the above, the energization of the auxiliary pump 34 is restricted when the auxiliary pump 34 is not in an operable state. For example, the DCU 40, the auxiliary pump 34, or the like is used to drive the auxiliary pump 34. A shutoff device or the like for shutting off the energization is provided, and after the operation diagnosis indicates that the auxiliary pump 34 is not in an operable state, the shutoff device cuts off the energization for driving the auxiliary pump 34. , The configuration may be such that the energization of the auxiliary pump 34 is restricted. In such a configuration, after the operation diagnosis determines that the auxiliary pump 34 is not in an operable state, for example, a control signal for driving the auxiliary pump 34 is output to the FET 44 due to a malfunction or the like. Even if this happens, it is possible to prevent the auxiliary pump 34 from being operated.

Although the examples of the embodiments of the present invention have been described above, the present invention is not limited to the examples of the present invention, and even if there are changes or additions within the range not deviating from the gist of the present invention, the present invention is described. Needless to say, it is included.

1 Internal combustion engine 4 DPF
7 Switch 11 Reducing agent addition valve 12 SCR catalyst 32 Refrigerant passage 33 Main pump 34 Auxiliary pump 40 DCU
41 Acquisition unit 42 Execution unit 50 Notification device

Claims (7)

An exhaust purification catalyst (12) that purifies the exhaust gas of the internal combustion engine (1), a reducing agent addition valve (11) that adds a reducing agent to the upstream side of the exhaust purification catalyst (12), and the internal combustion engine (1). An exhaust gas purification device (10) including a cooling device (30) for circulating the cooling medium of the above and cooling the reducing agent addition valve (11).
A control device (40) that controls the exhaust gas purification device (10) and
A main pump (33) provided in the cooling device (30) and driven by the driving force of the internal combustion engine (1) to circulate the cooling medium when the internal combustion engine (1) is in operation.
An auxiliary pump provided in the cooling device (30) that circulates the cooling medium by being driven by electric power regardless of the driving force of the internal combustion engine (1) when the internal combustion engine (1) is stopped. 34) and
With
The control device (40)
When the internal combustion engine (1) is started, the acquisition unit (41) that acquires start-related information that can specify that the internal combustion engine (1) is started, and
An execution unit (42) that executes operation diagnosis control for diagnosing whether or not the auxiliary pump (34) is in an operable state, and
With
The execution unit (42) operates the operation while executing test drive control for driving the auxiliary pump (34) for at least a predetermined period when the start-related information is acquired by the acquisition unit (41). An exhaust purification device that performs diagnostic control. The execution unit (42) is a switch (7) for stopping the operation of the internal combustion engine (1) after the operation of the switch (7) for starting the operation of the internal combustion engine (1) is performed. The exhaust according to claim 1, wherein when the internal combustion engine (1) is first started, the control of the test drive is executed and the control of the operation diagnosis is executed in the period until the operation of the above is performed. Purification device. The exhaust gas purification device (10) is
A notification device (50) for notifying whether or not the auxiliary pump (34) is in an operable state is provided.
The execution unit (42) is in a state in which the auxiliary pump (34) can be operated by the notification device (50) when it is determined in the operation diagnosis that the auxiliary pump (34) is not in an operable state. The exhaust gas purification device according to claim 1 or 2, which executes a notification control for notifying that the system is not. In the operation diagnosis, the execution unit (42) identifies whether or not the auxiliary pump (34) may have a battery short circuit, and the auxiliary pump (34) has a battery short circuit. The exhaust gas purification device according to any one of claims 1 to 3, which determines that the auxiliary pump (34) is not in an operable state when it is specified that there is a possibility. The execution unit (42) identifies whether or not there is a possibility that the power supply wiring of the auxiliary pump (34) may have a disconnection or a ground short circuit during the period when the auxiliary pump (34) is not driven. The exhaust according to any one of claims 1 to 4, which determines that the auxiliary pump (34) is not in an operable state when it is identified that a disconnection or a ground short circuit may have occurred. Purification device. Any of claims 1 to 5, wherein the executing unit (42) executes control for limiting energization of the auxiliary pump (34) after it is determined that the auxiliary pump (34) is not in an operable state. The exhaust purification device according to item 1. An exhaust purification catalyst (12) that purifies the exhaust gas of the internal combustion engine (1), a reducing agent addition valve (11) that adds a reducing agent to the upstream side of the exhaust purification catalyst (12), and the internal combustion engine (1). An exhaust gas purification device (10) including a cooling device (30) for circulating the cooling medium of the above and cooling the reducing agent addition valve (11).
A control device (40) that controls the exhaust gas purification device (10) and
A main pump (33) provided in the cooling device (30) and driven by the driving force of the internal combustion engine (1) to circulate the cooling medium when the internal combustion engine (1) is in operation.
An auxiliary pump provided in the cooling device (30) that circulates the cooling medium by being driven by electric power regardless of the driving force of the internal combustion engine (1) when the internal combustion engine (1) is stopped. 34) and
The control method of the exhaust gas purification device (10) comprising the above.
When the internal combustion engine (1) is started, an acquisition step of acquiring start-related information that can identify that the internal combustion engine (1) is started, and
An execution step for executing operation diagnosis control for diagnosing whether or not the auxiliary pump (34) is in an operable state, and an execution step.
The control device (40)
In the execution step, when the start-related information is acquired by the acquisition step, the exhaust gas purification that executes the control of the operation diagnosis while executing the control of test-driving the auxiliary pump (34) for at least a predetermined period of time. A control method for the device (10).

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