JP5286672B2 - Exhaust gas purification device for in-vehicle diesel engine - Google Patents

Description

  The present invention relates to an exhaust purification device for an on-vehicle diesel engine.

  In general, in a diesel engine mounted on a vehicle, combustion is performed in a so-called lean state in which the fuel injection amount is smaller than the intake air amount introduced into the combustion chamber in the engine low and medium load range. In such a lean state, oxygen exists excessively in the combustion chamber, so that the combustion temperature rises and the amount of nitrogen oxides contained in the exhaust gas increases.

  Therefore, in-vehicle diesel engines are provided with an exhaust gas recirculation mechanism that adjusts the amount of exhaust gas that is returned from the exhaust gas passage through the exhaust gas recirculation passage to the intake air passage by a metering valve, and is provided in the metering valve and the intake air passage according to the engine operating state. The opening degree of the intake throttle valve thus adjusted is adjusted so that a part of the exhaust gas is recirculated to the combustion chamber. In this way, in the engine low and medium load range, a part of the exhaust gas is recirculated to the combustion chamber, thereby lowering the combustion temperature of the air-fuel mixture and suppressing the generation of nitrogen oxides.

  In addition, in an in-vehicle diesel engine, in addition to such an exhaust gas recirculation mechanism, a filter that collects particulate matter (hereinafter referred to as PM) contained in exhaust gas is provided in an exhaust passage so as to suppress emission of PM into the atmosphere. I have to. When the amount of accumulated PM collected in such a filter increases, the pressure loss due to the filter increases, leading to a decrease in engine output and a deterioration in fuel consumption.

  Therefore, in the exhaust purification device for an in-vehicle diesel engine described in Patent Document 1, in order to recover the PM trapping function in the filter, the exhaust temperature is increased by increasing the engine speed while the vehicle is stopped, and the filter The filter regeneration process is performed to burn and remove the PM deposited on the catalyst.

By the way, during the execution of such filter regeneration processing, the engine rotation speed is higher than the engine rotation speed in the normal idling state. For example, when driving force is transmitted to the wheels based on the driver's start operation, the vehicle May pop out and cause a big shock. Therefore, when an accelerator operation or the like by the driver is detected, the regeneration process is interrupted in the middle so that the engine speed is reduced to the engine speed in the normal idling state.
Japanese Patent Laid-Open No. 4-86319 JP 2005-163604 A

  However, if the regeneration process is interrupted while a large amount of particulate matter is still deposited on the filter, the flow rate of the exhaust gas that passes through the filter decreases as the engine rotation speed decreases, and heat exchange occurs due to the passage of the exhaust gas. Since the action is reduced, the heat generated by the combustion of PM tends to be trapped in the filter. As a result, the PM in the filter burns one after another by the combustion heat of PM, and the temperature of the filter rises excessively. And when the temperature of a filter rises too much in this way, it will cause the PM collection function and durability fall in a filter.

  On the other hand, in the one described in Patent Document 2, when the filter regeneration process is started in order to suppress the overheating of the filter due to the interruption of such a regeneration process, the amount of PM deposited on the filter is a predetermined amount. Until it becomes below, the vehicle start operation is restricted by restricting the operation of the transmission or restricting the increase of the fuel injection amount with respect to the depression of the accelerator pedal. However, if the vehicle start operation is restricted in this way, the vehicle cannot be started until the filter regeneration process is completed, which leads to a decrease in vehicle operability.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress the occurrence of overheating of the filter even when the engine rotation speed is reduced as the regeneration process is interrupted. An object of the present invention is to provide an exhaust purification device for a vehicle-mounted diesel engine.

In the following, means for achieving the above object and its effects are described.
According to the first aspect of the present invention, there is provided an exhaust gas recirculation mechanism for adjusting the amount of exhaust gas returned from the exhaust gas passage through the exhaust gas recirculation passage to the intake air passage by a metering valve, and a portion where the exhaust gas recirculation passage is connected in the exhaust gas passage And a filter that collects particulate matter contained in the exhaust gas, and keeps at least the engine rotational speed at a constant rotational speed higher than a normal idle rotational speed while the vehicle is stopped. In the exhaust purification device of the on-board diesel engine that executes the filter regeneration process for burning and removing the particulate matter deposited on the particulate matter by raising the temperature of the vehicle, the filter regeneration process is interrupted when a start operation of the vehicle is detected, A limiting process for limiting the opening of the metering valve so as not to exceed a predetermined upper limit until a predetermined period elapses after the filter regeneration process is interrupted. As its gist to run.

  The gist of the invention described in claim 2 is that in the exhaust purification device of the on-board diesel engine according to claim 1, the metering valve is maintained in a fully closed state until the predetermined period elapses in the limiting process. And

  According to the configuration of the first aspect, when the regeneration operation is interrupted halfway, the engine operation state returns to the normal idling state, and the engine speed decreases, the metering is performed through the restriction process. The opening of the valve is restricted so as not to exceed a predetermined upper limit value. Therefore, the amount of exhaust gas recirculated to the combustion chamber through the exhaust gas recirculation passage is limited, and the amount of exhaust gas passing through the filter can be increased by the amount associated with the limitation. As a result, it is possible to ensure a heat exchange action between the filter and the exhaust when the exhaust passes through the filter, and even if the regeneration process is interrupted in the middle and the engine speed decreases, the filter It becomes possible to suppress overheating.

  In addition, in the restriction process, the recirculation of the exhaust gas is permitted under a state where the opening of the metering valve is restricted so as not to exceed a predetermined upper limit value. In addition, the upper limit is set to the minimum opening of the metering valve, in other words, the metering valve is maintained in a fully closed state until the predetermined period elapses to stop such exhaust gas recirculation. .

According to a third aspect of the present invention, there is provided a filter that is provided in the exhaust passage and collects particulate matter contained in the exhaust gas, and at least the engine rotational speed is higher than the normal idle rotational speed while the vehicle is stopped. When the vehicle start operation is detected in an exhaust purification device for an on-vehicle diesel engine that performs a filter regeneration process that raises the temperature of the filter by holding the filter and burns and removes particulate matter deposited on the filter. Limiting process that interrupts the filter regeneration process and limits the opening of the intake throttle valve provided in the intake passage from falling below a predetermined lower limit until a predetermined period elapses after the filter regeneration process is interrupted The gist is to execute.

  According to a fourth aspect of the present invention, in the exhaust purification device for an in-vehicle diesel engine according to the third aspect, the exhaust throttle valve is maintained in a fully open state until the predetermined period elapses during the restriction process. To do.

  According to the configuration of the third aspect, when the engine operation state returns to the normal idling state due to the regeneration process being interrupted in the middle, and the engine rotation speed decreases, the intake throttle is reduced through the restriction process. The opening of the valve is restricted so as not to fall below a predetermined lower limit value. Therefore, the reduction of the intake air amount by the intake throttle valve is restricted, and the intake air amount introduced into the combustion chamber is increased by the amount associated with the restriction, and the exhaust gas exhausted from the combustion chamber and passing through the filter is increased. The amount can be increased. As a result, it is possible to ensure a heat exchange action between the filter and the exhaust when the exhaust passes through the filter, and even if the regeneration process is interrupted in the middle and the engine speed decreases, the filter It becomes possible to suppress overheating.

  The restricting process is described in claim 4 in addition to a process that permits a reduction in the intake air amount in a state where the opening of the intake throttle valve is restricted so as not to fall below a predetermined lower limit value. As described above, the lower limit is set to the maximum opening of the intake throttle valve, in other words, the intake throttle valve is kept fully open until the predetermined period elapses, and the reduction of the intake air amount is prohibited. Is also included.

According to a fifth aspect of the present invention, there is provided an exhaust gas recirculation mechanism for adjusting the amount of exhaust gas returned from the exhaust gas passage through the exhaust gas recirculation passage to the intake air passage by a metering valve, and a portion where the exhaust gas recirculation passage is connected in the exhaust gas passage And a filter that collects particulate matter contained in the exhaust gas, and keeps at least the engine rotational speed at a constant rotational speed higher than a normal idle rotational speed while the vehicle is stopped. In the exhaust purification device of the on-board diesel engine that executes the filter regeneration process for burning and removing the particulate matter deposited on the particulate matter by raising the temperature of the vehicle, the filter regeneration process is interrupted when a start operation of the vehicle is detected, When the opening of the metering valve is limited so as not to exceed a predetermined upper limit until a predetermined period elapses after the filter regeneration process is interrupted. The opening degree of the intake throttle valve provided in an intake passage and its gist to perform the limit process for limiting so as not to fall below a predetermined lower limit value.

  According to a sixth aspect of the present invention, in the exhaust purification device for an in-vehicle diesel engine according to the fifth aspect, the metering valve is maintained in a fully closed state until the predetermined period elapses during the limiting process, and the intake throttle The gist is to keep the valve fully open.

  According to the configuration described in claim 5, when the regeneration process is interrupted halfway, the engine operating state returns to the normal idling state, and the engine speed decreases, the metering is performed through the restriction process. The opening degree of the valve is restricted so as not to exceed a predetermined upper limit value, and the opening degree of the intake throttle valve is restricted so as not to fall below a predetermined lower limit value. Therefore, the amount of exhaust gas recirculated to the combustion chamber through the exhaust gas recirculation passage is limited, and the reduction of the intake air amount introduced into the combustion chamber is limited. As a result, the amount of exhaust gas passing through the filter can be increased by the amount associated with these restrictions. Therefore, the heat exchange action between the filter and the exhaust gas when the exhaust gas passes through the filter can be ensured, and even if the regeneration process is interrupted and the engine rotation speed decreases, the filter overheating Can be suppressed.

  In the above limiting process, the valve opening of the metering valve is restricted so that it does not exceed a predetermined upper limit value. In addition to allowing the reduction of the intake air amount in a state where this is restricted so as not to fall below, the upper limit value is set as the minimum opening of the metering valve and the lower limit is set forth as described in claim 6 The value is the maximum opening of the intake throttle valve, in other words, the metering valve is maintained in a fully closed state until the predetermined period elapses, and the intake throttle valve is maintained in a fully open state.

  The invention according to claim 7 is the exhaust purification system for an in-vehicle diesel engine according to any one of claims 1 to 6, further comprising temperature estimation means for estimating the temperature of the filter, The gist of the present invention is that it is executed on the condition that the temperature of the filter when the regeneration process is interrupted is estimated by the temperature estimating means to be equal to or higher than a predetermined processing start temperature.

  When the temperature of the filter becomes equal to or higher than the combustion temperature of the particulate matter, the particulate matter deposited on the filter starts to burn. If the flow rate of the exhaust gas passing through the filter decreases when the particulate matter is burning, the filter may be overheated.

  In this regard, according to the configuration of the seventh aspect, according to the configuration in which the restriction process is executed on condition that the temperature of the filter estimated by the temperature estimation unit is equal to or higher than a predetermined process start temperature, It is possible to determine whether or not the filter is likely to be overheated due to a decrease in the flow rate of the filter based on the temperature estimated by the temperature estimation means. The restriction process can be executed in a manner.

Note that the processing start temperature is desirably set to a value smaller than the lower limit value based on the lower limit value of the filter temperature at which the particulate matter burns.
The invention according to claim 8 is the exhaust purification system for an on-board diesel engine according to any one of claims 1 to 7, further comprising temperature estimating means for estimating the temperature of the filter, The gist of the present invention is that the process is terminated on the condition that the temperature of the filter is estimated to be lower than a predetermined processing end temperature by the temperature estimation means.

  If the temperature of the filter is lower than the combustion temperature of the particulate matter, the particulate matter deposited on the filter will not burn. Therefore, if the temperature of the filter is lower than the combustion temperature of the particulate matter, even if the flow rate of the exhaust gas passing through the filter is reduced, there is no possibility that the filter is overheated.

  In this regard, according to the configuration of the eighth aspect of the invention, according to the configuration in which the limiting process is terminated on condition that the temperature of the filter estimated by the temperature estimation unit is lower than the predetermined processing end temperature, the exhaust gas is exhausted. Even if the flow rate of the filter decreases, it can be determined whether or not the filter is overheated based on the temperature of the filter estimated by the temperature estimation means, and the filter is overheated. The restriction process can be terminated in a manner that matches the possibility.

The processing end temperature is preferably set to a value smaller than the lower limit value based on the lower limit value of the filter temperature at which the particulate matter burns.
The invention according to claim 9 is the exhaust purification apparatus for an on-vehicle diesel engine according to any one of claims 1 to 8, further comprising a deposit amount estimating means for estimating the amount of particulate matter deposited on the filter. And the limiting process is executed on condition that the accumulated amount of the particulate matter when the regeneration process is interrupted is estimated by the accumulated amount estimating means to be equal to or greater than a predetermined process start accumulated amount. Is the gist.

  Even if the regeneration process is interrupted when particulate matter is burning, if the amount of particulate matter deposited on the filter is small, it will accumulate on the filter before the filter temperature rises excessively. The particulate matter burned out will burn out.

  In this regard, according to the ninth aspect of the invention, according to the configuration in which the limiting process is executed on condition that the deposition amount of the particulate matter estimated by the deposition amount estimation unit is equal to or greater than the processing start deposition amount. Whether or not the filter is likely to be overheated when the flow rate of the exhaust gas is reduced can be determined based on the amount of particulate matter accumulated estimated by the accumulation amount estimating means. It becomes possible to execute the limiting process in a manner in accordance with the possibility of overheating.

Note that the processing start deposition amount is preferably set to a value smaller than the lower limit value based on the lower limit value of the particulate matter deposition amount that may cause overheating.
A tenth aspect of the present invention is the exhaust purification system for an on-vehicle diesel engine according to any one of the first to ninth aspects, further comprising a deposit amount estimating means for estimating the amount of particulate matter deposited on the filter. The gist of the limiting process is that it is terminated on the condition that the deposition amount of the particulate matter is estimated by the deposition amount estimation means to be less than a predetermined processing completion deposition amount.

  According to the tenth aspect of the invention, according to the configuration in which the limiting process is terminated on condition that the deposition amount of the particulate matter estimated by the deposition amount estimating unit is less than the processing termination deposition amount, Whether or not the filter is overheated even when the flow rate is reduced, it can be determined based on the amount of particulate matter accumulated estimated by the accumulation amount estimation means. It is possible to end the restriction process in a manner in accordance with the possibility of occurrence of.

  It should be noted that the processing end deposition amount is preferably set to a value smaller than the lower limit value based on the lower limit value of the particulate matter deposition amount that may cause overheating.

Hereinafter, an embodiment of an exhaust emission control device for an in-vehicle diesel engine according to the present invention will be described with reference to FIGS.
FIG. 1 is a schematic diagram illustrating a schematic configuration of a diesel engine 10 and an exhaust purification device according to the present embodiment. As shown in FIG. 1, an intake passage 20 and an exhaust passage 30 are connected to the diesel engine 10. The intake passage 20 is provided with an intake throttle valve 21 that is opened and closed by a motor 21a. The amount of intake air introduced into the combustion chamber 11 is adjusted by changing the opening of the intake throttle valve 21. Is done.

  In the combustion chamber 11 of the diesel engine 10, an injector 12 for injecting fuel is provided for each cylinder. These injectors 12 are connected to a common rail 13 and fuel filled in the common rail 13 is injected. The common rail 13 is supplied with fuel pressurized by the high-pressure pump 14.

  As shown in FIG. 1, the intake passage 20 and the exhaust passage 30 are connected to a turbocharger 22. The turbocharger 22 rotates the turbine 22 a with the energy of the exhaust gas flowing through the exhaust passage 30 to pressurize the air in the intake passage 20 and send it into the combustion chamber 11.

  In addition, a catalytic converter 40 is provided in the exhaust passage 30. The catalytic converter 40 includes, in order from the upstream side, an oxidation catalyst 41 that oxidizes hydrocarbons (HC) and carbon monoxide (CO) in the exhaust, and a soot in the exhaust as a main component, which is formed of a porous material. And a filter 42 for collecting particulate matter (hereinafter referred to as PM).

  In the exhaust gas introduced into the catalytic converter 40, HC and CO are purified by the oxidation catalyst 41, and PM is collected by the filter 42, and their emission into the atmosphere is suppressed.

  Further, as shown in FIG. 1, an exhaust gas recirculation passage 43 that communicates with the intake passage 20 and recirculates part of the exhaust gas in the exhaust passage 30 to the intake passage 20 at a portion upstream of the turbocharger 22 in the exhaust passage 30. Is connected. The exhaust gas recirculation passage 43 is provided with an EGR valve 44 as a metering valve that is opened and closed by a linear solenoid 44a. By changing the opening degree of the EGR valve 44, the exhaust passage 30 is changed to the intake passage 20. The amount of exhaust gas that is recirculated is metered. The exhaust gas recirculation passage 43 and the EGR valve 44 constitute an exhaust gas recirculation mechanism (hereinafter referred to as an EGR mechanism) 45.

  The opening / closing control of the EGR valve 44 and the intake throttle valve 21 and the fuel injection control through the injector 12 are performed by an electronic control unit 50 that executes various controls of the diesel engine 10 in an integrated manner. The electronic control device 50 includes an air flow meter 51 for detecting the intake air amount, a rotational speed sensor 52 for detecting the engine rotational speed, and a vehicle speed sensor 53 for detecting the vehicle speed as various sensors for detecting the engine operating state and the vehicle traveling state. An accelerator opening sensor 54 that detects the depression amount of the accelerator pedal of the driver, a shift position sensor 55 that detects the operation position of the shift lever, and the like are connected, and detection signals of these various sensors are captured.

  The electronic control unit 50 performs calculations based on detection signals taken from these various sensors 51 to 55, and controls each part of the engine. For example, the target fuel injection amount for generating the engine torque according to the driver's request is calculated based on the depression amount of the accelerator pedal with respect to the detected vehicle speed, engine rotation speed, and the like. Then, the injector 12 is controlled so that the main injection amount, which is the fuel injection amount contributing to combustion, coincides with the target fuel injection amount.

  Further, when the amount of oxygen introduced into the combustion chamber 11 is excessive with respect to the main injection amount, the amount of nitrogen oxide generated due to engine combustion increases. Therefore, the electronic control unit 50 controls the opening degree of the intake throttle valve 21 and the EGR valve 44 according to the engine operating state detected by various sensors to recirculate part of the exhaust gas into the combustion chamber 11. By recirculating part of the exhaust gas to the combustion chamber 11 in this way, the combustion temperature of the air-fuel mixture can be lowered and the production of nitrogen oxides can be suppressed.

The exhaust gas purifying device for the diesel engine 10 of the present embodiment is configured including the EGR mechanism 45, the catalytic converter 40, and the electronic control device 50 for controlling them.
By the way, when the amount of accumulated PM collected by the filter 42 of the catalytic converter 40 increases, the pressure loss due to the filter 42 increases, leading to a decrease in engine output and a deterioration in fuel consumption. Therefore, in order to remove the PM accumulated in the filter 42, the engine regeneration speed is increased while the vehicle is stopped, and the PM accumulated in the filter 42 is burned by raising the exhaust gas temperature to regenerate the function of the filter 42. The process is executed.

  Specifically, the regeneration is made up of logical product conditions such as the vehicle speed being “0”, the accelerator pedal not being depressed, and the shift lever position being the stop position “P” or the neutral position “N”. When the regeneration processing switch 60 provided on the console of the driver's seat is operated from “OFF” to “ON” by the driver when the processing execution condition is satisfied and it is determined that the vehicle is stopped, The exhaust temperature is raised by increasing the main injection amount in the idling state and increasing the engine speed NE.

  Further, in order to further increase the exhaust gas temperature, so-called post-injection is performed in which fuel is injected at a time that does not contribute to combustion in the expansion stroke or exhaust stroke after main injection that contributes to combustion.

  The fuel supplied into the exhaust gas by the post injection is oxidized by the oxidation catalyst 41 in the catalytic converter 40. The exhaust temperature further increases due to the reaction heat of the oxidation reaction in the oxidation catalyst 41, and the temperature of the filter 42 provided on the downstream side of the oxidation catalyst 41 further increases.

  The amount of fuel added by the post injection is controlled based on the filter temperature THF. As shown in FIG. 1, a first exhaust temperature sensor 56 is provided between the oxidation catalyst 41 and the filter 42 in the catalytic converter 40 to detect an upstream exhaust temperature THupper that is an exhaust temperature upstream of the filter 42. . A second exhaust temperature sensor 57 is provided downstream of the filter 42 in the exhaust passage 30 to detect a downstream exhaust temperature THlower that is an exhaust temperature downstream of the filter 42. The exhaust temperature sensors 56 and 57 are connected to the electronic control unit 50, and the filter temperature THF is estimated based on the upstream exhaust temperature THupper and the downstream exhaust temperature THlower detected by these.

  More specifically, when the downstream exhaust temperature THlower is lower than the upstream exhaust temperature THupper, it is estimated that the filter temperature THF is lower than the upstream exhaust temperature THupper, and further the upstream exhaust temperature THupper. It is estimated that the filter temperature THF is lower as the temperature difference between the lower exhaust gas temperature THlower and the downstream exhaust temperature THlower increases. On the other hand, when the upstream exhaust temperature THupper is lower than the downstream exhaust temperature THlower, the filter temperature THF is estimated to be higher than the upstream exhaust temperature THupper, and further, the upstream exhaust temperature THupper and the downstream exhaust temperature are estimated. It is estimated that the filter temperature THF is higher as the temperature difference of the temperature THlower is larger.

  The electronic control unit 50 controls the post injection amount so that the filter temperature THF estimated in this way becomes a temperature suitable for the filter regeneration process. Thus, the filter temperature THF rises, and PM deposited on the filter 42 is burned and removed.

  During the filter regeneration process, the EGR valve 44 is maintained in the fully closed state and the intake throttle valve 21 is maintained in the fully open state in order to prevent the fuel from the post injection from returning to the intake passage 20 and contributing to combustion. Reflux is stopped.

  By the way, during the execution of such filter regeneration processing, the engine rotational speed NE is higher than the engine rotational speed in the normal idling state, so, for example, when the driving force is transmitted to the wheel based on the driver's start operation, The vehicle may jump out and cause a big shock.

  Therefore, the start operation by the driver, such as when the shift lever is changed from the stop position “P” or the neutral position “N” to the forward position “D” or the reverse position “R” or the accelerator pedal is depressed, is reproduced. When the process execution condition is not satisfied, the filter regeneration process is interrupted halfway, and the engine speed is reduced to the engine speed in the normal idling state.

  However, if the filter regeneration process is interrupted while a large amount of PM is still deposited on the filter 42, the flow rate of the exhaust gas passing through the filter 42 decreases as the engine speed decreases, and the heat generated by the exhaust gas passing through the filter 42 decreases. Since the exchange action is reduced, the heat generated by the combustion of PM is easily trapped in the filter 42.

  In particular, when the exhaust gas is recirculated by the EGR mechanism 45 in the same way as in the normal idling state when the filter regeneration process is interrupted and the engine speed is reduced to the engine speed in the normal idling state, the exhaust gas in the exhaust passage 30 is exhausted. The flow rate of the exhaust gas passing through the catalytic converter 40 located on the downstream side of the portion to which the reflux passage 43 is connected further decreases.

  As a result, the PM in the filter 42 burns one after another by the combustion heat of PM, and the filter temperature THF rises excessively. If the filter temperature THF rises excessively in this way, the PM collecting function and durability of the filter 42 are reduced.

  Therefore, in the exhaust purification device of the present embodiment, when the filter regeneration process is interrupted in the middle, the intake throttle valve 21 is maintained in a fully opened state until a predetermined period has elapsed since the interruption, and the EGR valve 44. Is maintained in a fully closed state, thereby executing a restriction process for restricting the exhaust flow rate so as not to drop below a predetermined amount.

  Hereinafter, this restriction process will be described with reference to FIGS. FIG. 2 is a flowchart showing a series of the restriction process. This process is executed by the electronic control unit 50 when the filter regeneration process is interrupted as described above.

  When this process is started, first, in step S100, as described above, the filter temperature THF estimated based on the detection values of the first exhaust temperature sensor 56 and the second exhaust temperature sensor 57 is equal to or higher than the process start temperature THFs. It is determined whether or not.

  The processing start temperature THFs is set as a temperature lower than the PM combustion temperature based on the PM combustion temperature which is the lower limit value of the temperature at which PM deposited on the filter 42 burns. That is, when the filter temperature THF is lower than the processing start temperature THFs, PM deposited on the filter does not burn.

  When it is determined in step S100 that the filter temperature THF is equal to or higher than the processing start temperature THFs (step S100: YES), that is, PM accumulated on the filter 42 is burned, and the filter regeneration process is interrupted and passes through the filter. If there is a possibility that the combustion of PM may continue due to a decrease in the exhaust gas flow rate, the process proceeds to step S110.

In step S110, it is determined whether or not the PM deposition amount QPM is equal to or greater than the processing start deposition amount QPMs.
Note that the processing start accumulation amount QPMs is based on the results of experiments and the like performed in advance, even when PM combustion continues after the filter regeneration processing is interrupted, before the filter 42 is overheated. Based on the amount of deposition that burns out, a value smaller than this amount is set.

  In calculating the PM accumulation amount QPM, the PM discharge amount QPMex is first calculated based on the engine speed, the main fuel injection amount, and the like, and the PM combustion amount in the filter 42 is calculated based on the filter temperature THF, the intake air amount, and the like. QPMcom is calculated. Based on the PM emission amount QPMex and the PM combustion amount QPMcom, the PM accumulation amount QPM is estimated. Specifically, the current PM accumulation amount QPM is calculated by adding the PM emission amount QPMex newly discharged to the previously estimated PM accumulation amount QPM and subtracting the PM combustion amount QPMcom burned in the filter 42. The

  When it is determined in step S110 that the PM accumulation amount QPM is equal to or greater than the processing start accumulation amount QPMs (step S110: YES), that is, when the filter regeneration process is interrupted, PM combustion continues and the filter 42 is overheated. If there is a possibility of occurrence, the process proceeds to step S120.

In step S120, a restriction process is executed to maintain the intake throttle valve 21 in the fully open state and the EGR valve 44 in the fully closed state regardless of the engine operating state.
On the other hand, if it is determined in step S100 that the filter temperature THF is lower than the processing start temperature THFs (step S100: NO), that is, the filter temperature THF is a temperature at which PM does not burn, the regeneration process is interrupted and the filter is filtered. Even if the flow rate of the exhaust gas passing through the exhaust gas decreases, if there is no risk of overheating of the filter, the process proceeds to step S150, and the restriction of the intake throttle valve 21 and the EGR valve 44 is not performed. Normal control for changing the opening according to the engine operating state is executed.

  Further, when it is determined in step S110 that the PM accumulation amount QPM is less than the processing start accumulation amount QPMs (step S110: NO), that is, when PM combustion continues after the filter regeneration process is interrupted. However, if the PM burns out before the filter temperature THF rises excessively and there is no possibility of overheating of the filter 42, the routine similarly proceeds to step S150 and normal control is executed.

  In step S120, when the restriction process is executed and the intake throttle valve 21 is fully opened and the EGR valve 44 is kept fully closed, the process proceeds to step S130, where the PM accumulation amount QPM is equal to or greater than the process completion accumulation amount QPMf. It is determined whether or not.

  The processing end deposition amount QPMf is set to a value smaller than the deposition amount on the basis of the PM deposition amount that is unlikely to cause overheating even when the combustion continues in the same manner as the processing start deposition amount QPMs. The Further, in order to more reliably suppress overheating of the filter 42, the processing end accumulation amount QPMf is set to a value smaller than the processing start accumulation amount QPMs.

  In step S130, when it is determined that the PM accumulation amount QPM is equal to or larger than the processing completion accumulation amount QPMf (step S130: YES), that is, the openings of the intake throttle valve 21 and the EGR valve 44 are changed according to the engine operating state. If the flow rate of the exhaust gas passing through the filter 42 decreases and the PM 42 continues to burn, there is a possibility that the filter 42 is overheated, and the process proceeds to step S140.

In step S140, it is determined whether or not the filter temperature THF is lower than the processing end temperature THFf.
The processing end temperature THFf is set as a temperature lower than the PM combustion temperature, similarly to the processing start temperature THFs, and is set to a temperature lower than the processing start temperature THFs in order to more reliably suppress overheating of the filter 42. Has been.

  If it is determined in step S140 that the filter temperature THF is equal to or higher than the processing end temperature THFf (step S140: NO), that is, if the PM deposited on the filter 42 may be burned, the process proceeds to step S120. Returning, the restriction process is continued.

  On the other hand, if it is determined in step S130 that the PM accumulation amount QPM is less than the processing end accumulation amount QPMf (step S130: NO), that is, the limiting process is terminated and the routine proceeds to normal control, and the exhaust gas passes through the filter 42. Even if the flow rate decreases, the PM burns out before the filter 42 is overheated. If there is no possibility of overheating, the process proceeds to step S150.

  In Step S140, when it is estimated that the filter temperature THF is lower than the processing end temperature THFf (Step S140: YES), that is, the filter temperature THF is equal to or lower than the PM combustion temperature, and PM is not combusted. If the flow rate of the exhaust gas passing through the filter 42 is reduced and there is no risk of overheating of the filter, the process proceeds to step S150.

  In step S150, the execution of the restriction process is terminated, and the routine proceeds to normal control in which the opening amounts of the intake throttle valve 21 and the EGR valve 44 are changed according to the engine operating state. In this way, when it transfers to normal control through step S150, this process will be complete | finished.

Next, with reference to FIG. 3 and FIG. 4, the relationship between the open / close state of the intake throttle valve 21 and the EGR valve 44 and the change in the filter temperature THF accompanying the execution of the restriction process will be described.
As shown in FIG. 3, when the regeneration processing switch 60 is turned “ON” by the driver at time t <b> 1 and the filter regeneration processing is executed, the main injection amount is increased and the engine rotational speed NE reaches the regeneration processing rotational speed NEu. To rise. Further, post injection is performed, and fuel is added to the exhaust. At this time, the EGR valve 44 is maintained in the fully closed state and the intake throttle valve 21 is maintained in the fully open state as described above in order to suppress the return of fuel to the intake passage 20 due to post injection.

Thus, the regeneration process is executed, and the exhaust gas temperature rises, whereby the filter temperature THF starts to rise.
When the filter temperature THF becomes equal to or higher than the PM combustion temperature at time t2, the PM deposited on the filter 42 starts to combust and the PM combustion amount QPMcom increases, so the PM accumulation amount QPM starts to decrease.

  When the driver performs a start operation at time t3 and the regeneration process execution condition is not satisfied, the filter regeneration process is interrupted. When the filter regeneration process is interrupted, post-injection is stopped, and the engine rotational speed NE is reduced to the normal idle rotational speed NEi.

  At this time, if the opening degree of the intake throttle valve 21 and the EGR valve 44 is changed according to the engine operating state as indicated by a broken line in FIG. 3, the exhaust gas is recirculated to the intake passage 20, and the filter 42. The amount of exhaust passing through the engine will be reduced. As a result, the heat exchange effect with the filter 42 is greatly reduced along with the reduction of the exhaust flow rate as the engine rotational speed NE is reduced, and the filter temperature THF is excessively increased as shown by the broken line in FIG. Will rise.

  On the other hand, when it is determined that the filter temperature THF is equal to or higher than the processing start temperature THFs and equal to or higher than the processing start accumulation amount QPMs at the time t3 when the filter regeneration process is interrupted, the exhaust purification device of the present embodiment described above. Execute the restricted process. By executing the restriction process, the intake throttle valve 21 is maintained in the fully open state, and the EGR valve 44 is maintained in the fully closed state. Therefore, a decrease in the exhaust flow rate is suppressed.

  Moreover, the generation of heat of oxidation in the oxidation catalyst 41 is suppressed by stopping the post injection, and the filter temperature THF gradually decreases as the exhaust gas temperature decreases. However, since the filter temperature THF is higher than the PM combustion temperature, the PM deposited on the filter 42 continues to burn, and the PM deposition amount QPM gradually decreases.

  At time t4, when the filter temperature THF becomes lower than the PM combustion temperature, PM combustion does not occur, and the PM accumulation amount QPM gradually increases as the engine operation continues.

  When it is determined at time t5 that the filter temperature THF is lower than the processing end temperature THFf, the limiting process is ended, and the normal control in which the opening degrees of the intake throttle valve 21 and the EGR valve 44 are changed according to the engine operating state. Migrate to

  Further, for example, as indicated by a one-dot chain line in FIG. 3, when the filter regeneration process is continued until time t6, the PM accumulation amount QPM at time t6 is smaller than the process start accumulation amount QPMs, and thus the restriction process is executed. Not.

  In this case, as soon as the filter regeneration process is interrupted halfway at time t6, the openings of the intake throttle valve 21 and the EGR valve 44 are changed according to the engine operating state. Therefore, the filter temperature THF rises due to the combustion of PM and the decrease in the flow rate of the exhaust gas passing through the filter 42, but the PM burns out at time t7, and thereafter the combustion does not proceed, and the filter temperature THF gradually decreases. No overheating of 42 occurs.

  Further, as shown in FIG. 4, at time t3, the filter regeneration process is interrupted in the middle, and when it is estimated that the PM accumulation amount QPM is less than the processing completion accumulation amount QPMf at time t8 during execution of the limiting process, Even if the filter temperature THF does not fall below the processing end temperature THFf, the limiting process is ended, and the opening degrees of the intake throttle valve 21 and the EGR valve 44 are changed according to the engine operating state.

  As a result, the flow rate of the exhaust gas passing through the filter 42 decreases when PM is burning, so that the filter temperature THF rises. However, PM burns out at time t9, and thereafter combustion does not proceed. As a result, the filter temperature THF decreases.

According to the embodiment described above, the following effects can be obtained.
(1) When the engine regeneration state returns to the normal idling state due to the interruption of the filter regeneration process, and the engine speed NE decreases, the EGR valve 44 is maintained in the fully closed state through the restriction process. Become so. Therefore, the amount of exhaust gas recirculated to the combustion chamber 11 through the exhaust gas recirculation passage 43 is limited, and the amount of exhaust gas passing through the filter 42 can be increased by the amount associated with the limitation. As a result, even when the exhaust gas passes through the filter 42, the heat exchange action between the filter 42 and the exhaust gas can be secured, and even when the regeneration process is interrupted and the engine rotational speed NE decreases. The overheating of the filter 42 can be suppressed.

  (2) When the engine regeneration state returns to the normal idling state due to the interruption of the filter regeneration process, and the engine speed NE decreases, the intake throttle valve 21 is maintained in the fully open state through the restriction process. Become so. Therefore, the reduction of the intake air amount by the intake throttle valve 21 is restricted, the intake air amount introduced into the combustion chamber 11 is increased by the restriction, and the filter 42 is exhausted from the combustion chamber 11 and discharged. The amount of exhaust passing therethrough can be increased. As a result, even when the exhaust gas passes through the filter 42, the heat exchange action between the filter 42 and the exhaust gas can be secured, and even when the regeneration process is interrupted and the engine rotational speed NE decreases. The overheating of the filter 42 can be suppressed.

  (3) When the engine regeneration state returns to the normal idling state due to the filter regeneration process being interrupted halfway, and the engine speed NE decreases, the EGR valve 44 is maintained in the fully closed state through the restriction process. As a result, the intake throttle valve 21 is maintained in a fully open state. Therefore, the amount of exhaust gas recirculated to the combustion chamber 11 through the exhaust gas recirculation passage 43 is restricted, and the reduction of the intake air amount introduced into the combustion chamber 11 is restricted. As a result, the amount of exhaust gas passing through the filter 42 can be increased by the amount associated with these restrictions. Therefore, the heat exchange action between the filter 42 and the exhaust gas when the exhaust gas passes through the filter 42 can be secured, and even when the regeneration process is interrupted in the middle and the engine rotational speed NE decreases, The overheating of the filter 42 can be suppressed.

  (4) Since the limiting process is executed on condition that the filter temperature THF is equal to or higher than the predetermined processing start temperature THFs, whether or not the filter 42 is likely to be overheated due to a decrease in the exhaust gas flow rate. Can be determined on the basis of the filter temperature THF, and the restriction process can be executed in a manner in accordance with the possibility of overheating of the filter 42.

  (5) Since the limiting process is completed on condition that the filter temperature THF is lower than the predetermined processing end temperature THFf, the filter 42 is not overheated even when the flow rate of the exhaust gas is decreased. It is possible to determine whether or not based on the filter temperature THF, and it is possible to end the limiting process in a manner in accordance with the possibility of the filter 42 being overheated.

  (6) Whether or not the filter 42 is likely to be overheated when the flow rate of the exhaust gas decreases because the limiting process is executed on condition that the PM accumulation amount QPM is equal to or greater than the processing start accumulation amount QPMs. Can be determined based on the PM accumulation amount QPM, and the limiting process can be executed in a manner in accordance with the possibility of overheating of the filter 42.

  (7) Whether the filter 42 is overheated or not even if the exhaust gas flow rate is reduced because the limiting process is terminated on the condition that the PM deposition amount QPM is less than the processing termination deposition amount QPMf. It is possible to determine whether or not it is based on the PM accumulation amount QPM, and it is possible to finish the limiting process in a manner in accordance with the possibility that the filter 42 is overheated.

In addition, this embodiment can also be implemented with the following form which changed this suitably.
The processing start deposition amount QPMs and the processing end deposition amount QPMf are set to values smaller than the deposition amount that burns out before overheating occurs when the exhaust flow rate decreases when PM deposited on the filter 42 is burning. The processing end deposition amount QPMf may be set to a value larger than the processing start deposition amount QPMs. Moreover, these may be set to the same value.

  The process start temperature THFs and the process end temperature THFf may be set to a temperature lower than the PM combustion temperature, and the process end temperature THFf may be set to a temperature higher than the process start temperature THFs. Moreover, these may be set to the same temperature.

  A configuration in which the filter temperature THF and the PM deposition amount QPM are estimated, and if the PM deposition amount is less than the processing end deposition amount QPMf, and if the filter temperature THF is less than the processing end temperature THFf, the limiting process is terminated. Indicated. On the other hand, only the PM deposition amount QPM is estimated, and the configuration in which the limiting process is terminated when the PM deposition amount QPM is less than the processing end deposition amount QPMf, or only the filter temperature THF is estimated, and the filter temperature THF is processed. It is also possible to adopt a configuration in which the restriction process is ended when the end temperature is lower than THFf. Even in such a case, it is possible to end the restriction process in a manner in accordance with the possibility of the filter 42 being overheated.

  In addition, it is possible to adopt a configuration in which the restriction process is terminated when the execution of the restriction process continues for a certain period regardless of the filter temperature THF or the PM accumulation amount QPM. As described above, when the execution of the restriction process is continued, the execution period is set to a period during which the filter temperature THF is reliably lowered to a temperature at which PM does not burn.

  -Estimate the filter temperature THF and the PM deposition amount QPM, and execute the limiting process when it is determined that the filter temperature THF is equal to or higher than the processing start temperature THFs and the PM deposition amount QPM is equal to or higher than the processing start deposition amount QPMs. The configuration to do was shown. On the other hand, the restriction process is performed when it is determined that the filter temperature THF is equal to or higher than the processing start temperature THFs and the PM deposition amount QPM is equal to or higher than the processing start deposition amount QPMs. It is also possible to adopt a configuration in which Even in such a case, it is possible to execute the limiting process in accordance with the possibility of overheating of the filter 42 and suppress the occurrence of overheating of the filter 42.

  In addition, in order to suppress the occurrence of overheating of the filter 42, the filter temperature THF and the PM accumulation amount QPM are not estimated, and the filter regeneration process is interrupted halfway, and the restriction process is always executed. Can also be adopted. According to such a configuration, the overheating of the filter 42 can be suppressed by executing the limiting process.

  In the restriction process, the EGR valve 44 is fully closed and the intake throttle valve 21 is maintained in the fully open state. However, the EGR valve 44 is maintained in the fully closed state and the opening of the intake throttle valve 21 is set to a predetermined value. It is also possible to adopt a configuration that restricts so as not to fall below the lower limit value. Further, the intake throttle valve 21 is maintained in a fully opened state and the opening degree of the EGR valve 44 is limited so as not to exceed a predetermined upper limit value, or the opening degree of the EGR valve 44 is not exceeded a predetermined upper limit value. It is also possible to adopt a configuration that restricts the opening of the intake throttle valve 21 so as not to fall below a predetermined lower limit. That is, if the configuration that can secure the flow rate of the exhaust gas passing through the filter 42 by restricting the opening degrees of the EGR valve 44 and the intake throttle valve 21 is used, the overheating of the filter 42 can be suppressed.

  In addition, in order to secure the amount of exhaust gas that passes through the filter 42 through the restriction process, a configuration in which only the opening degree of the EGR valve 44 is limited can be employed, and even when such a configuration is employed, the EGR valve In addition to the configuration in which 44 is maintained in the fully closed state, a configuration in which the opening degree of the EGR valve 44 is limited so as not to fall below a predetermined upper limit value may be employed.

  A configuration in which only the opening degree of the intake throttle valve 21 is limited can also be adopted. Similarly, the opening degree of the intake throttle valve 21 is set to a predetermined lower limit in addition to the configuration in which the intake throttle valve 21 is maintained in a fully open state. It is also possible to adopt a configuration that restricts so as not to fall below.

  -Although the structure which estimates filter temperature THF based on the detected value of the 1st exhaust temperature sensor 56 and the 2nd exhaust temperature sensor 57 was shown, this invention is not limited to such a structure. That is, the temperature estimation means may be any means that can estimate the temperature of the filter 42. For example, a configuration in which a thermocouple that directly detects the temperature of the filter 42 is provided can be adopted.

  PM accumulation amount based on PM emission amount QPMex calculated based on engine rotation speed, main fuel injection amount, etc., and PM combustion amount QPMcom in filter 42 calculated based on filter temperature THF, intake air amount, etc. A configuration for estimating the QPM is shown. In contrast, the present invention is not limited to such a configuration. That is, the accumulation amount estimation means may be any means that can estimate the accumulation amount of PM accumulated on the filter 42, for example, immediately before the catalytic converter 40 in the exhaust passage 30 as indicated by a broken line in FIG. A configuration in which a pressure sensor 58 is provided and an increase in pressure loss due to an increase in the amount of accumulated PM is estimated from a change in exhaust pressure detected by the pressure sensor 58 to estimate the amount of PM accumulated QPM, or a detected value of the pressure sensor 58 It is also possible to adopt a configuration in which the PM accumulation amount is estimated based on both the PM accumulation amount QPM estimated by the above-described calculation.

  Although the configuration in which the filter regeneration process is executed when the regeneration process switch 60 is turned “ON” by the driver while the vehicle is stopped is shown, the regeneration process is automatically performed on the condition that the vehicle is stopped. The present invention can also be applied to an exhaust purification device that executes the above.

  In the above embodiment, as an example of when the filter regeneration process is interrupted in the middle, the start operation by the driver is detected and the regeneration process execution condition is not established, but this is not a limitation. For example, when the regeneration process switch 60 is operated from “ON” to “OFF” by the driver during the filter regeneration process, or when the filter regeneration process is interrupted halfway, such as when a system abnormality is detected. Can suppress overheating of the filter 42 by executing the limiting process according to the present invention.

  Although post injection has been shown as a method of adding fuel to the exhaust during the filter regeneration process, a dedicated fuel addition valve for adding fuel to the exhaust is provided in the exhaust passage 30 and the oxidation catalyst 41 is unburned by the fuel addition valve. The present invention can also be applied to an exhaust purification device that supplies fuel.

  In the above embodiment, the configuration in which the oxidation catalyst 41 and the filter 42 are disposed in order from the upstream side of the exhaust gas is shown in the catalytic converter 40, but the configuration of the catalytic converter is not limited to such a configuration, It may be a catalytic converter on which an oxidation catalyst is supported.

  Further, the present invention can also be applied to an exhaust purification apparatus that does not include an oxidation catalyst and that overheats the filter only at the exhaust temperature increased by the increase in the main injection amount during the regeneration process and executes the filter regeneration process. .

1 is a schematic diagram showing a schematic configuration of a diesel engine and an exhaust purification device thereof according to an embodiment of the present invention. The flowchart which shows a series of the flows of the restriction | limiting process concerning the embodiment. The time chart which shows the relationship between the change of the opening degree of an EGR valve and an intake throttle valve, and the change of filter temperature in the restriction | limiting process concerning the embodiment. The time chart which shows the relationship between the change of the opening degree of an EGR valve and an intake throttle valve, and the change of filter temperature in the restriction | limiting process concerning the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Diesel engine, 11 ... Combustion chamber, 12 ... Injector, 13 ... Common rail, 14 ... High pressure pump, 20 ... Intake passage, 21 ... Intake throttle valve, 21a ... Motor, 22 ... Turbocharger, 30 ... Exhaust passage, 40 ... Catalytic converter, 41 ... oxidation catalyst, 42 ... filter, 43 ... exhaust recirculation passage, 44 ... EGR valve, 44a ... linear solenoid, 45 ... EGR mechanism, 50 ... electronic control unit, 51 ... air flow meter, 52 ... rotational speed sensor, 53 ... Vehicle speed sensor, 54 ... Accelerator opening sensor, 55 ... Shift position sensor, 56 ... First exhaust temperature sensor, 57 ... Second exhaust temperature sensor, 60 ... Regeneration processing switch.

Claims (10)

An exhaust gas recirculation mechanism that adjusts the amount of exhaust gas that is returned from the exhaust gas passage through the exhaust gas recirculation passage to the intake air passage by a metering valve, and a downstream side of the exhaust passage where the exhaust gas recirculation passage is connected. And a filter that collects particulate matter contained therein, and keeps at least the engine rotational speed at a constant rotational speed higher than the normal idle rotational speed while the vehicle is stopped to raise the temperature of the filter and deposit it on the filter. In-vehicle diesel engine exhaust gas purification apparatus that performs filter regeneration processing to burn off and remove particulate matter,
The filter regeneration process is interrupted when a start operation of the vehicle is detected so that the opening of the metering valve does not exceed a predetermined upper limit until a predetermined period elapses after the filter regeneration process is interrupted. An exhaust emission control device for an on-board diesel engine characterized by executing a limiting process for limiting. The exhaust emission control device for an in-vehicle diesel engine according to claim 1,
An exhaust purification device for an on-vehicle diesel engine, wherein the metering valve is maintained in a fully closed state during the restriction process until the predetermined period elapses. The filter is provided in the exhaust passage and collects particulate matter contained in the exhaust gas, and maintains the temperature of the filter by maintaining at least the engine rotational speed at a constant rotational speed higher than the normal idle rotational speed while the vehicle is stopped. In an exhaust purification device for an in-vehicle diesel engine that executes a filter regeneration process that burns and removes particulate matter deposited on the
The filter regeneration process is interrupted when a start operation of the vehicle is detected, and the opening degree of the intake throttle valve provided in the intake passage is a predetermined lower limit until a predetermined period elapses after the filter regeneration process is interrupted. An exhaust purification device for an on-board diesel engine, characterized by executing a restriction process for restricting the value so as not to fall below a value. The exhaust emission control device for an in-vehicle diesel engine according to claim 3,
The exhaust purification device for an on-board diesel engine, wherein the intake throttle valve is maintained in a fully opened state until the predetermined period elapses during the restriction process. An exhaust gas recirculation mechanism that adjusts the amount of exhaust gas that is returned from the exhaust gas passage through the exhaust gas recirculation passage to the intake air passage by a metering valve, and a downstream side of the exhaust passage where the exhaust gas recirculation passage is connected. And a filter that collects particulate matter contained therein, and keeps at least the engine rotational speed at a constant rotational speed higher than the normal idle rotational speed while the vehicle is stopped to raise the temperature of the filter and deposit it on the filter. In-vehicle diesel engine exhaust gas purification apparatus that performs filter regeneration processing to burn off and remove particulate matter,
The filter regeneration process is interrupted when a start operation of the vehicle is detected, and the opening of the metering valve does not exceed a predetermined upper limit until a predetermined period elapses after the filter regeneration process is interrupted. An exhaust purification device for an in-vehicle diesel engine, characterized in that a restriction process is executed to restrict the opening of an intake throttle valve provided in an intake passage so as not to fall below a predetermined lower limit value. The exhaust purification device for an on-board diesel engine according to claim 5,
The exhaust purification device for an on-vehicle diesel engine, wherein the restriction valve is maintained in a fully closed state and the intake throttle valve is maintained in a fully open state until the predetermined period elapses during the restriction process. In the exhaust emission control device for a vehicle-mounted diesel engine according to any one of claims 1 to 6,
The temperature estimation means for estimating the temperature of the filter is further provided, and the limiting process estimates that the temperature of the filter when the regeneration process is interrupted is equal to or higher than a predetermined process start temperature by the temperature estimation means. An exhaust purification device for an in-vehicle diesel engine, characterized in that the exhaust gas purification device is executed on the condition. In the exhaust emission control device of the on-board diesel engine according to any one of claims 1 to 7,
Temperature limiting means for estimating the temperature of the filter, and the limiting process is terminated on the condition that the temperature of the filter is estimated by the temperature estimating means to be lower than a predetermined processing end temperature. An exhaust purification system for on-board diesel engines. In the exhaust emission control device of the on-board diesel engine according to any one of claims 1 to 8,
The amount of particulate matter deposited on the filter is further estimated, and the limiting process is performed so that the amount of particulate matter deposited when the regeneration process is interrupted is determined by the deposit amount estimation unit. An exhaust purification apparatus for an on-vehicle diesel engine, which is executed on the condition that it is estimated that the amount is greater than a processing start accumulation amount. In the exhaust emission control device for a vehicle-mounted diesel engine according to any one of claims 1 to 9,
The amount of particulate matter deposited on the filter is estimated, and the limiting process is estimated that the amount of particulate matter deposited is less than a predetermined processing-terminated deposition amount by the deposition amount estimation unit. The exhaust purification system for an on-board diesel engine, characterized in that the exhaust purification device is terminated on the condition that

Images