JP4390790B2 - Wastegate valve control device for an internal combustion engine with a supercharger - Google Patents

Description

  The present invention relates to a control device for a wastegate valve interposed in a bypass passage that bypasses a turbine of a supercharger in an internal combustion engine with a supercharger.

  In an internal combustion engine with a supercharger, an example is proposed in which a supercharging pressure sensor is provided in an intake passage, and the opening degree of a wastegate is feedback controlled based on a measured supercharging pressure of the supercharging pressure sensor (for example, a patent) Reference 1).

JP 2000-345851 A

  In Patent Document 1, it is disclosed that, when it is determined that the supercharging pressure sensor has failed, supercharging pressure control is performed by follow-up control that does not use the measured supercharging pressure.

  However, there is no disclosure of waste gate valve control when abnormality occurs in the knock CPU related to supercharging pressure control in an internal combustion engine with a supercharger.

  The present invention has been made in view of the above points, and the object of the present invention is to provide a wastegate valve control device that appropriately controls the wastegate valve when an abnormality occurs in the knock CPU.

In order to achieve the above object, the invention described in claim 1 is a supercharger comprising a turbine disposed in an exhaust passage and a compressor disposed in an intake passage, and a bypass bypassing the turbocharger turbine in the exhaust passage. A waste gate valve interposed in the passage, a waste gate valve driving mechanism for driving the waste gate valve, a knock sensor for detecting vibration of the internal combustion engine, and a value corresponding to a vibration frequency from a detection signal of the knock sensor In the internal combustion engine with a supercharger provided with a knocking CPU for extracting the engine and a control means for controlling the wastegate valve driving mechanism based on a signal from the knocking CPU, the abnormality of the knocking CPU from a different viewpoint comprising a knocking CPU abnormality determination means for determining a double, CPU abnormality determining means for said knock, C for the knock The signal from the knocking CPU can be received normally at the signal presence / absence determination that determines that there is an abnormality when the signal from U has not continued for a predetermined time, and the counter value K that is 0 when the value is negative. The subtraction value a is subtracted when the signal from the knocking CPU is not normally received, and the addition value b smaller than the subtraction value a is added, and the counter value K becomes equal to or greater than the predetermined value k. Reception state determination that is sometimes determined to be abnormal is performed independently of each other, and when the control means determines that the knock CPU is abnormal by the knock sensor or the knock CPU abnormality determination means, the waste gate valve A wastegate valve control device for an internal combustion engine with a supercharger that controls the wastegate valve drive mechanism so as to suppress supercharging by the supercharger to a predetermined pressure or less.

According to the wastegate valve control device for an internal combustion engine with a supercharger according to claim 1, even when an abnormality occurs in the knock sensor or the knock CPU, the knock CPU is provided with the double determination means. Therefore, it is possible to reliably detect an abnormality without leakage, and to prevent overshoot of the supercharging pressure, that is, occurrence of knocking, engine overspeed, and the like.
Therefore, the reliability and durability of the internal combustion engine are remarkably improved.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 shows a schematic configuration diagram of an internal combustion engine with a supercharger and a wastegate valve control device according to the present embodiment.

  In the internal combustion engine 1, an intake passage 4 for intake air and an exhaust passage 5 for exhaust gas extend from a combustion chamber in a cylinder 2 in which a piston 3 reciprocates, and a turbine 11 disposed in the exhaust passage 5 A turbocharger 10 is configured by integrating a compressor 12 disposed in the intake passage 4.

  An air cleaner 6 is provided at an upstream end portion of the intake passage 4 from the compressor 12, and an intercooler 7 and a throttle valve 8 are sequentially arranged downstream of the compressor 12.

  An exhaust bypass passage 20 that bypasses the turbine 11 of the turbocharger 10 and communicates the upstream side and the downstream side of the turbine 11 is provided in the exhaust passage 5, and a wastegate valve 21 is interposed in the exhaust bypass passage 20. The exhaust valve bypass 20 is opened and closed by the gate valve 21.

The waste gate valve 21 communicates with the pressure chamber 24 b of the diaphragm actuator 24 and is opened and closed by the diaphragm actuator 24.
The diaphragm chamber 24 a of the diaphragm actuator 24 communicates with the intake passage 4 upstream of the compressor 12 via the pressure guide passage 25.

  A wastegate solenoid valve 26 is interposed in the middle of the pressure guide passage 25, and the wastegate solenoid valve 26 is driven to open and close by a wastegate solenoid 27.

  In addition, the branch passage 25a branches off from the waste gate solenoid valve 26 on the pressure guide passage 25 and communicates with the intake passage 4 on the downstream side of the compressor 12, and an orifice 28 is formed in the branch passage 25a.

  As described above, the diaphragm type actuator 24, the waste gate solenoid 27, and the like constitute the waste gate valve drive mechanism 23.

  In the waste gate valve drive mechanism 23, when the waste gate solenoid 27 is energized, the waste gate solenoid valve 26 opens the pressure guide passage 25, introduces intake pressure into the diaphragm chamber 24a of the diaphragm actuator 24, and boosts the pressure chamber 24b. A wastegate valve 21 closes the exhaust bypass passage 20.

  When the energization to the waste gate solenoid 27 is cut off, the pressure in the diaphragm chamber 24a of the diaphragm actuator 24 is released, and the waste gate valve 21 opens the exhaust bypass passage 20 by the pressure reduction in the pressure chamber 24b.

  The energization to the wastegate solenoid 27 is performed by a pulse drive signal whose duty ratio is controlled, and the opening degree of the wastegate by the wastegate valve 21 is controlled by the duty ratio. Supercharging is promoted by flowing toward the turbine 11.

  Therefore, when the energization to the wastegate solenoid 27 is turned off and the wastegate valve 21 opens the exhaust bypass passage 20, the exhaust gas almost flows through the exhaust bypass passage 20 and the supercharging pressure by the supercharger 10 is a small predetermined pressure. It is suppressed to the following.

  The intake passage 4 is provided with an air bypass passage 30 that bypasses the compressor 12 and connects the downstream side of the intercooler 7 and the upstream side of the compressor 12, and a relief valve 32 is interposed in the air bypass passage 30. Has been.

The relief valve 32 is a diaphragm type valve. The inside of the valve body 32a is divided into a diaphragm chamber 32d and a communication chamber 32e by a diaphragm 32c to which a valve body 32b is attached. Is going.
The valve body 32b is urged in the closing direction by a spring 32f.

  When the pressure in the communication chamber 32e becomes higher than the pressure in the diaphragm chamber 32d by a predetermined pressure or more, the valve body 32b opens and communicates with the air bypass passage 30 to recirculate the supercharging pressure on the downstream side of the compressor 12 to the upstream side. Relieve.

  The diaphragm chamber 32d communicates with an output port 35c of an air bypass valve 35, which is a three-port solenoid valve. The input port 35b of the air bypass valve 35 communicates with the downstream side of the throttle valve 8, and another input port 35a. Is in communication with the upstream side of the throttle valve 8.

  As described above, the air bypass valve mechanism 31 is configured. When the air bypass solenoid 36 is demagnetized, the input port 35b is closed and the input port 35a is opened, so that the intake negative pressure on the downstream side of the throttle valve 8 is output. Acting on the diaphragm chamber 32d of the relief valve 32 through the port 35c, the relief valve 32 is brought into a valve-openable state.

  When the air bypass solenoid 36 is excited, the input port 35a is closed and the input port 35b is opened, whereby the intake pressure upstream of the throttle valve 8 acts on the diaphragm chamber 32d of the relief valve 32 via the output port 35c. The relief valve 32 is maintained in the closed state by the urging force of the spring 32 with the same pressure as the communication chamber 32e.

  Therefore, when the energization to the air bypass solenoid 36 is turned off, the relief valve 32 can be opened, and the relief valve 32 is opened to open the air bypass passage when the supercharging pressure of the supercharger 10 exceeds a predetermined pressure. 30 will communicate and decompress.

A knock sensor 40 for detecting vibration is attached to the cylinder 2 of the internal combustion engine 1, and a detection signal of the knock sensor 40 is taken out as a voltage corresponding to the vibration frequency by the knock CPU 41, and an ECU (Electronic Control Unit) 50. Is input.
The ECU 50 determines the presence or absence of knocking from the input voltage.

  In addition, the ECU 50 receives and processes signals from various sensors indicating the operating state of the internal combustion engine 1, such as the engine speed Ne, the throttle opening Th, the intake negative pressure Pb, the atmospheric pressure Pa, the intake air temperature T, and the like. Various controls are performed, and control of the waste gate solenoid 27 of the waste gate valve drive mechanism 23 and control of the air bypass solenoid 36 of the air bypass valve mechanism 31 are also performed.

  In the supercharged internal combustion engine 1 as described above, the ECU 50 determines whether or not the knock sensor 40 or the knock CPU 41 and the air bypass valve mechanism 31 are abnormal, and controls the waste gate valve drive mechanism 23 according to the presence or absence of the abnormality. This will be described below with reference to the flowcharts of FIGS.

First, the procedure for determining whether the knock sensor 40 is abnormal will be described with reference to the flowchart shown in FIG.
The flow is executed every cycle of the internal combustion engine.

  It is determined whether or not the internal combustion engine 1 is starting (step 1). If the engine is starting, the process proceeds to step 2 to initialize the normal state timer (set and start the normal down timer). The abnormal state timer is initialized (the abnormal down timer is set and started), and the presence information of the knock sensor signal is initialized (cleared) in the next step 4.

If it is determined in step 1 that the internal combustion engine 1 has been completely started, the process proceeds to step 5 to determine the presence or absence of a knock sensor signal.
If there is a knock sensor signal, the process proceeds to step 6 to determine whether the normal state has passed for a predetermined time by the normal state timer, and until the time has passed, in steps 3 and 4, the failure state timer and the information with the knock sensor signal are initialized each time. To do.

When the normal state has elapsed for a predetermined time, the process proceeds from step 6 to step 7, the normal state is determined, the abnormality flag Fa is set to “0”, and steps 3 and 4 are executed.
Therefore, if there is always a knock sensor signal for each cycle, it is determined that the knock sensor 40 is normal, and the abnormality flag Fa is “0”.

  However, if there is no knock sensor signal, the process proceeds from step 5 to step 8 to initialize the normal state timer, and it is determined whether or not it is lower than a predetermined water temperature (step 9) and lower than a predetermined engine speed (step 10). When the temperature is lower than the water temperature or lower than the predetermined engine speed, the process proceeds to steps 3 and 4 and no abnormality determination is performed.

  When the predetermined water temperature and the predetermined engine speed are exceeded, the routine proceeds to step 11 where it is determined whether or not the abnormal state has elapsed by the abnormal state timer, and this routine is exited until the predetermined time has elapsed. Proceeding to step 12, it is determined that there is an abnormality, and “1” is set in the abnormality flag Fa.

  As described above, the abnormality of the knock sensor 40 is determined based on the presence or absence of the knock sensor signal. When the knock sensor 40 is normal, the abnormality flag Fa = 0. However, when an abnormality occurs, the abnormality flag Fa is set to “1”.

Next, a procedure for determining abnormality of the knocking CPU 41 depending on the presence / absence of a signal from the knocking CPU 41 will be described with reference to the flowchart of FIG.
First, the presence / absence of a signal from the knocking CPU 41 is determined (step 21), and if there is the signal, the process proceeds to step 22 where it is normal and the abnormality flag Fb = 0 is set, and the abnormal state timer is initialized (step 23).

  When it is determined in step 21 that there is no signal from the knocking CPU 41, the routine proceeds to step 24, where it is determined whether or not the abnormal state has elapsed by the abnormal state timer. When the time has elapsed, the routine proceeds to step 25, where it is determined that there is an abnormality, and the abnormality flag Fb is set to “1”.

Further, the procedure for determining the communication abnormality of the knocking CPU 41 will be described with reference to the flowchart of FIG.
First, it is determined whether or not the engine speed Ne is equal to or less than a predetermined speed N ₁ (for example, 400 rpm) (step 31). If N ₁ or less, the routine jumps to step 32 and the count value K of the abnormality counter is cleared, and then the abnormality flag Fc. = 0 (step 32).

When the engine speed Ne exceeds a predetermined rotational speed N _1, the process proceeds turn the engine rotational speed Ne step 34 it is determined whether a predetermined rotational speed N _{2 (e.g.,} 1200 rpm) or more from the step 31, if N2 or more steps the process proceeds to step 36 to allow the implementation of communication abnormality determination of knocking CPU41 proceeds to 35, the process proceeds without permission step 36 exemplary communication abnormality determined to be less than N _2.

  In step 36, it is determined whether or not a predetermined time has elapsed after the engine is started. If not, the process proceeds to step 37 to determine whether or not the execution of the communication abnormality determination is permitted first. When the predetermined time has not elapsed since the start and communication abnormality determination is not permitted, the process jumps to step 32 and communication abnormality determination is not performed.

If the execution of the communication abnormality determination is permitted first even if the predetermined time has not elapsed after the engine is started, the routine proceeds to step 38.
If it is determined in step 36 that a predetermined time has elapsed after the engine is started, the process directly jumps to step 38.

  As described above, when it becomes possible to reliably determine whether the knocking CPU 41 is in communication abnormality, the process proceeds to step 38 to determine whether or not the data has been normally received from the knocking CPU 41. Proceeding to step 39, if the predetermined number a is subtracted from the count value K of the abnormal counter and the count value K is negative (step 40), the count value K is set to 0 (step 41). If the count value K ≧ 0 (step 40), the process jumps directly to step 43.

  If the data cannot be normally received from the knocking CPU 41 at step 38, the process jumps to step 42, adds the predetermined number b (<a) to the count value K of the abnormality counter, and proceeds to step 43.

  Therefore, the count value K of the abnormality counter increases when the ratio of data that cannot be normally received is large to some extent, and it is determined in step 43 whether or not this count value K is equal to or greater than the predetermined value k. When it is over k, the routine proceeds to step 44, where it is determined that the knocking CPU 41 is in communication abnormality and "1" is set in the abnormality flag Fc.

  If the knock sensor 40 or the knocking CPU 41 is abnormal as described above, “1” is set in any of the abnormality flags Fa, Fb, and Fc.

  Next, a procedure for determining an abnormality of the air bypass valve mechanism 31 that controls opening and closing of the air bypass passage 30 provided in the intake passage 4 will be described with reference to the flowchart of FIG.

First, it is determined whether or not the IG1 voltage applied to the air bypass solenoid 36 that opens and closes the air bypass valve 35 is equal to or lower than a predetermined voltage (step 51). Then, proceed to step 52 to determine the OFF normal state (OFF abnormal flag Foff = 0), initialize the OFF abnormal state timer (step 53), initialize the ON abnormal state timer (step 54), and turn ON normal in step 55 Is determined (ON abnormality flag Fon = 0).

When it is determined in step 51 that the IG1 voltage exceeds the predetermined voltage, an abnormality determination of the air bypass valve mechanism 31 is performed, and the process jumps to step 60.
In step 60, it is determined whether or not an air bypass valve (ABV) signal has issued an ON command, that is, an energization command to the air bypass solenoid 36, and there is a case where there is no ON command and a case where there is no ON command. Judge abnormalities.

If there is no ON command, the process proceeds to step 61 to determine whether the air bypass valve mechanism 31 is OFF abnormal. If there is an ON command, the process proceeds to step 71 to determine whether the air bypass valve mechanism 31 is ON abnormal.
In either case, the abnormality is determined by the same procedure.

A case in which there is no ABV signal ON command and the process proceeds to step 61 will be described below in accordance with steps 61 to 69.
In step 61, the ON abnormal condition timer is initialized, the ON normal condition timer is initialized (step 62), and the ABV signal is detected (returned) in step 63 and turned OFF.
Determine if it is a signal.

  If it is an OFF signal, it is normal. Proceeding to step 64, the OFF abnormal state timer is initialized, and at step 65, it is determined by the OFF normal state timer whether or not the OFF normal state has elapsed, and the predetermined time has elapsed. Sometimes the routine proceeds to step 66, where the OFF normal state is determined, and the OFF abnormality flag Foff = 0.

If the result of detecting (returning) the ABV signal in step 63 is not an OFF signal, the process proceeds to step 67 instead of the normal state, and it is determined by the OFF abnormal state timer whether or not the predetermined time has elapsed. When elapses, the routine proceeds to step 68, where the OFF abnormal state is determined, and the OFF abnormal flag Foff is set to "1".
Then, the OFF normal state timer is initialized (step 69).

  The above is the abnormality determination procedure when there is no ABV signal ON command, and when there is an ABV signal ON command, the procedure jumps from step 60 to step 71, and abnormality determination is performed in a substantially similar procedure.

  That is, the OFF abnormal state timer is initialized (step 71), the OFF normal state timer is initialized (step 72), and the ABV signal is detected (returned) to determine whether it is an ON signal (step 63).

  If it is an ON signal, it is normal, the process proceeds to step 74, the ON abnormal condition timer is initialized, and it is determined by the ON normal condition timer whether or not the ON normal condition has elapsed for a predetermined time (step 75), and the predetermined time has elapsed. If YES, the routine proceeds to step 76, where the ON normal state is determined, and the ON abnormality flag Fon = 0.

  If the result of detecting (returning) the ABV signal in step 73 is not an ON signal, the process proceeds to step 77, not the normal state, and whether or not the ON abnormal state has elapsed for a predetermined time is determined by the ON abnormal state timer, and the predetermined time When elapses, the routine proceeds to step 78, where the OFF abnormal state is determined, the OFF abnormal flag Fon is set to "1", and the ON normal state timer is initialized (step 79).

In this way, ABV signal abnormality is determined for each of the cases where there is no ABV signal ON command and when there is no ONV command. If there is an abnormality when there is no ON command, the OFF abnormality flag Foff is set to “1”. If there is an abnormality, the ON abnormality flag Fon is set to “1”.

As described above, each abnormality of the knock sensor 40, the knocking CPU 41, and the air bypass valve mechanism 31 is determined, and the abnormality flags Fa, Fb, Fc, Foff,
Based on Fon, the waste gate valve drive mechanism 23 is controlled.

The control procedure of the waste gate valve drive mechanism 23 will be described with reference to the flowchart shown in FIG.
First, at step 81, the throttle opening degree Th indicating the operating state of the internal combustion engine 1, the engine speed Ne, the intake air temperature T, the atmospheric pressure Pa, etc., and the abnormal flags Fa, Fb, Fc,
Input Foff and Fon data.

From the next step 82 to step 86, it is determined whether or not each abnormality flag Fa, Fb, Fc, Foff, Fon is set to “1”, and “1” is set to any abnormality flag. If it is determined that all are normal, the process proceeds to step 87.

  In step 87, the basic boost pressure Po is calculated from the throttle opening Th and the engine speed Ne, and in the next step 88, the basic boost pressure Po is corrected based on the intake air temperature T and the atmospheric pressure Pa to obtain the final boost pressure. Pf is calculated.

The wastegate solenoid 27 is duty-controlled by the calculated final supercharging pressure Pf (step 89).
That is, when all of the knock sensor 40, the knocking CPU 41, and the air bypass valve mechanism 31 are normal, the opening of the waste gate valve 21 is controlled based on the final supercharging pressure Pf.

There is an abnormality in any of knock sensor 40, knock CPU 41, and air bypass valve mechanism 31, and at least one of abnormality flags Fa, Fb, Fc, Foff, and Fon is “
If "1" stands, the process jumps to step 90, and energization to the wastegate solenoid 27 is turned off.

  When the energization to the wastegate solenoid 27 is turned off, the wastegate solenoid valve 26 is closed, negative pressure acts on the diaphragm actuator 24a to open the wastegate valve 21, and the exhaust gas is almost allowed to flow through the exhaust bypass passage 20. The supercharging pressure by the feeder 10 is controlled to a small predetermined pressure or less.

  Therefore, when an abnormality occurs in knock sensor 40 or knocking CPU 41, it is possible to suppress the occurrence of knocking due to the increase in supercharging pressure and to protect internal combustion engine 1.

  In addition, even when an abnormality occurs in the air bypass valve mechanism 31, the supercharging pressure is controlled to a small predetermined pressure or less to suppress the occurrence of surge noise during deceleration, etc. It is possible to prevent detachment and overshoot of supercharging pressure.

1 is a schematic configuration diagram of an internal combustion engine with a supercharger and a wastegate valve control device according to an embodiment of the present invention. It is a flowchart which shows the procedure which determines abnormality of a knock sensor. It is a flowchart which shows the procedure which determines abnormality of knocking CPU. It is a flowchart which shows the procedure which determines the communication abnormality of knocking CPU. It is a flowchart which shows the procedure which determines the abnormality of an air bypass valve mechanism. It is a flowchart which shows the control procedure of a waste gate valve drive mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Cylinder, 3 ... Piston, 4 ... Intake passage, 5 ... Exhaust passage, 6 ... Air cleaner, 7 ... Intercooler, 8 ... Throttle valve,
10 ... supercharger, 11 ... turbine, 12 ... compressor,
20 ... Exhaust bypass passage, 21 ... Wastegate valve, 23 ... Wastegate valve drive mechanism, 24 ... Diaphragm actuator, 25 ... Pressure guide passage, 26 ... Wastegate solenoid valve, 27 ... Wastegate solenoid, 28 ... Orifice,
30 ... Air bypass passage, 31 ... Air bypass valve mechanism, 32 ... Relief valve, 35 ... Air bypass valve, 36 ... Air bypass solenoid,
40 ... Knock sensor, 41 ... Knock CPU,
50 ... ECU.

Claims (1)

A turbocharger comprising a turbine disposed in the exhaust passage and a compressor disposed in the intake passage;
A wastegate valve interposed in a bypass passage that bypasses the turbocharger turbine in the exhaust passage;
A wastegate valve drive mechanism for driving the wastegate valve;
A knock sensor for detecting vibrations of the internal combustion engine;
A knock CPU for extracting a value corresponding to a vibration frequency from the detection signal of the knock sensor;
In the internal combustion engine with a supercharger, comprising a control means for controlling the wastegate valve drive mechanism based on a signal from the knocking CPU,
A knocking CPU abnormality determining means that doublely determines abnormality of the knocking CPU from different viewpoints;
The knocking CPU abnormality determination means sets a signal presence / absence determination that determines an abnormality when the signal from the knocking CPU does not continue for a predetermined time, and a counter value K that is 0 when a negative value is obtained. When the signal from the knocking CPU is normally received, the subtraction value a is subtracted, and when the signal from the knocking CPU is not normally received, the addition value b smaller than the subtraction value a is added, The reception state determination for determining an abnormality when the counter value K is equal to or greater than a predetermined value k is performed independently of each other,
When the knocking sensor or the knocking CPU abnormality determining means determines that the knocking CPU is abnormal, the control means opens the wastegate valve to suppress supercharging by the supercharger to a predetermined pressure or less. A wastegate valve control device for an internal combustion engine with a supercharger, wherein the wastegate valve drive mechanism is controlled.

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