JP4124517B2 - Internal combustion engine with a supercharger - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a supercharged internal combustion engine having a supercharger for supercharging air sucked into a combustion chamber.
[0002]
[Prior art]
In an engine equipped with a turbocharger, a compressor is driven by a turbine that is rotated by exhaust gas from the engine, and intake air supplied into the combustion chamber is supercharged by the compressor. On the other hand, as a method for supplying fuel to the engine, there is a method in which gasoline is supplied from an ejector by obtaining the amount of gasoline required to achieve a target air-fuel ratio, and directly into the combustion chamber. Some have one or both of an in-cylinder injector that injects fuel and an in-cylinder injector that injects fuel into the intake passage.
[0003]
As an in-cylinder direct injection internal combustion engine having an in-cylinder injector for injecting fuel into a combustion chamber and a supercharger, there is one disclosed in, for example, Japanese Patent Laid-Open No. 62-237057.
[0004]
In an internal combustion engine having a supercharger, the supercharging pressure in the intake passage is detected by a pressure sensor so that the supercharging pressure does not rise above a predetermined value, and the supercharging pressure becomes a predetermined value or more. In this case, the supercharging pressure solenoid is operated, and a bypass passage that bypasses the turbine is opened by a waste gate valve so that the supercharging pressure does not exceed a predetermined value.
[0005]
If the pressure sensor for detecting the supercharging pressure fails, the engine cannot be operated properly. Therefore, a supercharging pressure control method having a fail-safe function is disclosed, for example, in Japanese Patent Laid-Open No. 7-208230 Has been.
[0006]
In this case, fuel is injected from the in-cylinder injector into the intake passage. If the supercharging pressure is within a predetermined value, fuel corresponding to the supercharging pressure is injected from the out-of-cylinder injector into the intake passage. Even if the supercharging pressure exceeds the abnormal pressure value, if the engine speed is below a predetermined value, an amount of fuel corresponding to the engine speed is injected, and the supercharging pressure is abnormal. When the pressure value is exceeded and the engine speed exceeds a predetermined value, the fuel supply is stopped or decreased, or the engine speed is set to a predetermined value or less.
[0007]
In this way, when a predetermined amount of fuel is injected from the in-cylinder injector into the intake passage when the pressure sensor fails, the pulse width applied to the solenoid for operating the in-cylinder injector is set. By limiting, a fail-safe function can be provided.
[0008]
[Problems to be solved by the invention]
However, in an engine having an in-cylinder injector, the combustion mode is switched to either stratified combustion or uniform combustion according to the operating state, and the intake air amount is greatly different depending on the combustion mode.
[0009]
Therefore, when a failure occurs in the pressure sensor that detects the supercharging pressure or the supercharging pressure solenoid that adjusts the supercharging pressure, only the pulse width for the solenoid for operating the injector is controlled to perform fail-safe. Then, at the time of fail-safe, combustion cannot be stabilized. This is because if the injection amount is changed corresponding to the intake air amount during stratified combustion, there is a risk of misfire.
[0010]
An object of the present invention is to stabilize combustion in an internal combustion engine having a supercharger even when either a supercharging pressure solenoid that adjusts supercharging pressure or a pressure sensor that detects pressure in an intake passage fails. There is in doing so.
[0011]
[Means for Solving the Problems]
  An internal combustion engine with a supercharger according to the present invention is an internal combustion engine with a supercharger having a supercharger that supercharges air sucked into a combustion chamber, wherein the supercharging pressure in an intake passage communicating with the combustion chamber A supercharging pressure solenoid for adjusting the supercharging pressure, a supercharging pressure solenoid failure determining means for determining failure of the supercharging pressure solenoid, and fuel in the combustion chamberDirectlyAn in-cylinder injector for injection;An in-cylinder injector for injecting fuel into the intake passage;Combustion that determines the combustion mode in the combustion chamber according to the operating conditions, adjusts the opening of the throttle valve and the fuel injection amount, and sets the combustion mode to uniform combustion when the boost pressure solenoid fails And determining means.
[0012]
  An internal combustion engine with a supercharger according to the present invention is an internal combustion engine with a supercharger having a supercharger for supercharging air sucked into a combustion chamber, wherein the intake air in an intake passage communicating with the combustion chamber is reduced. Pressure sensor for detecting absolute pressure and atmospheric pressure, and determining failure of the pressure sensorPressure sensorFailure determination means and fuel into the combustion chamberDirectlyAn in-cylinder injector for injection;An in-cylinder injector for injecting fuel into the intake passage;Combustion determining means that determines the combustion mode in the combustion chamber according to the operating condition, adjusts the opening of the throttle valve and the fuel injection amount, and sets the combustion mode to uniform combustion when a failure of the pressure sensor occurs It is characterized by having.
[0013]
  An internal combustion engine with a supercharger according to the present invention is an internal combustion engine with a supercharger having a supercharger for supercharging air sucked into a combustion chamber, wherein the intake air in an intake passage communicating with the combustion chamber is reduced. A pressure sensor that detects absolute pressure and atmospheric pressure, a supercharging pressure solenoid that adjusts the supercharging pressure in the intake passage, and a failure of the pressure sensor are determined.Pressure sensorFailure determination means, boost pressure solenoid failure determination means for determining failure of the boost pressure solenoid, and fuel in the combustion chamberDirectlyAn in-cylinder injector for injection;An in-cylinder injector for injecting fuel into the intake passage;The combustion mode in the combustion chamber is determined in accordance with the operating conditions, the throttle valve opening and the fuel injection amount are adjusted, and the combustion mode when any of the pressure sensor and the supercharging pressure solenoid fails And combustion determining means for setting the combustion to uniform combustion.
  In the internal combustion engine with a supercharger according to the present invention, the supercharging pressure solenoid failure determination means detects an operation signal for operating the supercharging pressure solenoid, and determines whether the signal is normal. The failure determination of the supercharging pressure solenoid is performed. Further, in the internal combustion engine with a supercharger according to the present invention, the pressure sensor failure determination means compares the difference between the latest atmospheric pressure detection value detected by the pressure sensor and the previous atmospheric pressure detection value with a predetermined value. The fault diagnosis of the pressure sensor is performed. Furthermore, in the internal combustion engine with a supercharger according to the present invention, the pressure sensor failure determination means compares the output voltage of the pressure sensor with a predetermined value to determine the failure of the pressure sensor.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a schematic view of an internal combustion engine having a supercharger. An engine body is formed by a cylinder block 1 and a cylinder head 2 provided on the cylinder block 1. A crankshaft 5 is rotatably provided in a crank chamber 4 formed by a cylinder block 1 and an oil pan 3 provided in the lower part thereof, and a piston 6 provided in a cylinder bore so as to be capable of reciprocating in an axial direction is provided. The connecting rod 7 is connected to the crankshaft 5. In order to detect the rotation angle of the crankshaft 5, a crank angle sensor 9 is provided, and the rotation speed of the crankshaft 5, that is, the engine rotation speed, can be detected from a signal from the crank angle sensor 9. The cylinder block 1 is provided with a predetermined number of pistons 6 such as four or six, but only one is shown in FIG.
[0016]
An intake port 10 for supplying air necessary for combustion to the combustion chamber 8 in the engine body and an exhaust port 11 for discharging the burned gas are formed in the cylinder head 2 respectively. The exhaust port 11 is opened and closed by an exhaust valve 13.
[0017]
The engine body is provided with an intake system 15, an exhaust system 16, and a fuel supply system 17, and the intake system 15 is provided with an intake pipe 20 provided with an intercooler 19 that cools air flowing in through an air cleaner 18 that purifies the introduced air. And an intake manifold 22 having an intake pipe branching portion 21 branched and connected to the intake port 10. The intake manifold 22 has a collect chamber 23 that communicates with each intake port 10 via an intake pipe branching portion 21. The intake system 15 is provided with an air flow meter 24 for detecting the amount of intake air and a throttle valve 25a for adjusting the amount of air supplied to the combustion chamber 8. The throttle valve 25a is an electronic valve. It is driven by a throttle control (ETC) device 25.
[0018]
The exhaust system 16 includes an exhaust manifold 26 in which exhaust pipes connected to the exhaust port 11 are assembled, and an exhaust pipe 29 including a catalyst 27 and a muffler 28.
[0019]
The illustrated engine includes a supercharger, that is, a turbocharger 31. The turbocharger 31 includes a turbine 32 that is rotated by exhaust gas, and a compressor 33 that is driven by the turbine 32 and pressurizes intake air. A bypass passage 34 is provided at the turbine inlet of the exhaust pipe 29 so as to bypass the turbine 32 in order to adjust the supercharging pressure. The bypass passage 34 is opened and closed by a waste gate valve 35. The waste gate valve 35 is driven by an actuator 36, and the actuator 36 is operated by a supercharging pressure solenoid 37, whereby the supercharging pressure by the turbocharger 31 is adjusted.
[0020]
In order to switch and detect the absolute pressure and the atmospheric pressure of the intake air in the intake passage, a pressure sensor 38 is provided in the conduction pipe 40 communicating with the intake passage, and the pressure is controlled by a switching valve 39a operated by a switching solenoid 39. The sensor 38 is set by switching between a state communicating with the intake passage and a state communicating with the atmosphere. The pressure sensor 38 detects the atmospheric pressure when it is in communication with the atmospheric pressure. On the other hand, the pressure sensor 38 detects the pressure of the intake air when it is in communication with the intake passage, and the pressure sensor 38 detects the supercharging pressure when the intake air is supercharged by the turbocharger 31. .
[0021]
The cylinder head 2 is provided with an in-cylinder injector 41, which is also called a high pressure injector, for injecting fuel into the combustion chamber 8, and the intake manifold 22 injects fuel into the intake pipe passage just before the intake valve 12. An out-cylinder injector 42, which is also called a low pressure injector, is attached.
[0022]
In order to supply fuel to the in-cylinder injector 42, a low-pressure fuel supply pipe 45 having a low-pressure pump 43 and a filter 44 is connected between the in-cylinder injector 42 and the fuel tank 46, and the fuel pressure injected from the in-cylinder injector 42. That is, the fuel pressure is adjusted by the low pressure regulator 47.
[0023]
In order to supply fuel to the in-cylinder injector 41, a high-pressure fuel pump 52 is provided in the high-pressure fuel supply pipe 51 connected between the common rail 48 connected to the in-cylinder injector 41 and the low-pressure fuel supply pipe 45. The in-cylinder injector 41 injects fuel at a fuel pressure pressurized by the high-pressure fuel pump 52. The high pressure fuel supply pipe 51 is provided with a check valve 53 and a bypass valve 54.
[0024]
The engine shown in FIG. 1 is provided with an EGR device (not shown) that returns a part of the exhaust gas to the intake system, and reduces the maximum temperature of the combustion gas to suppress the generation of NOx. A part of the exhaust gas can be supplied to the intake system or stopped by turning on and off the EGR valve according to the operating condition. Further, the catalyst 27 has a NOx storage catalyst, and when the NOx storage amount of the catalyst 27 exceeds the reference value, the NOx purification of the catalyst 27 can be performed by performing a rich spike.
[0025]
In the illustrated engine, the combustion mode can be changed by adjusting the fuel injection amount from the in-cylinder injector 41, the injection timing, and the intake air amount.
[0026]
As the combustion mode, stratified combustion in which a rich mixture of fuel and a thin mixture of thin fuel are formed in the mixture in the combustion chamber so that the rich mixture is ignited; It can be classified into uniform combustion with a uniform concentration as a whole. Uniform combustion includes stoichiometric combustion in which combustion is performed at or near the stoichiometric air-fuel ratio, uniform lean combustion in which the fuel is thinner than the stoichiometric air-fuel ratio, and uniform rich combustion in which the fuel is thicker than the stoichiometric air-fuel ratio. In the case of stoichiometric combustion, there are cases where the EGR is operated and stopped. In the case of stratified combustion, the air-fuel mixture in the combustion chamber is set to be thinner than the stoichiometric air-fuel ratio as a whole, resulting in stratified lean combustion.
[0027]
Accordingly, there are five combustion modes as shown below. That is, uniform stoichiometric combustion (combustion form A) with EGR deactivated, uniform stoichiometric combustion (combustion form B) with EGR activated, uniform lean combustion (combustion form C), stratified lean combustion (combustion form D), There is uniform rich combustion (combustion form E).
[0028]
The illustrated engine is provided with a turbocharger 31, and the supercharging pressure is increased so that a large amount of air is supplied into the combustion chamber. When the fuel injection amount from the inner injector 41 does not correspond to the intake air amount, a shortage of fuel is supplied from the in-cylinder injector 42.
[0029]
Combustion modes A to D are selected according to the engine speed and target torque, and combustion mode E is set when the engine is started, fully opened, and when rich spike is performed. The combustion mode E is also set when the temperature of the engine coolant is equal to or lower than a predetermined value.
[0030]
In both stratified combustion and uniform combustion, the intake air amount is adjusted by the ETC device so that the target air-fuel ratio is set based on the target torque and the engine speed, and the fuel from the respective injectors 41 and 42 The injection amount is adjusted. When switching from stratified combustion to uniform combustion, control is performed so that the fuel injection amount is increased and the intake air amount is decreased, and the injection timing is the compression process injection up to the stratified limit air-fuel ratio, and thereafter the intake process injection is performed. When switching from homogeneous combustion to stratified combustion, control is performed so that the fuel injection amount is decreased and the intake air amount is increased, and the injection timing is the intake process injection up to the uniform limit air-fuel ratio, and thereafter the compression process injection is performed. Become.
[0031]
FIG. 2 sets one of the combustion modes A to E described above according to the operating state of the engine, and whether or not the boost pressure solenoid 37 has failed and whether or not the pressure sensor 38 has failed. When either of them fails, a control circuit for controlling the ETC device 25 and both the in-cylinder and the out-cylinder injectors 41 and 42 is set so that the combustion mode is set to the uniform combustion of the combustion mode A. FIG.
[0032]
An electronic control unit (ECU) 61 as a control means has a CPU 62, a ROM 63, and a RAM 64, which are connected via a bus line.
[0033]
A crank angle sensor 9 is connected to the CPU 62, and an engine speed is detected by calculating a signal interval based on a signal from the sensor 9. Further, a water temperature sensor 65 for detecting the temperature of the engine coolant and an accelerator opening sensor 67 for detecting the depression amount of the accelerator pedal 66 are connected to the CPU 62, and further, a rich spike command signal for performing a rich spike. 68 is sent to the CPU 62. The rich spike command signal 68 is sent from the sensor 27 when a sensor for detecting the storage amount of NOx in the catalyst 27 is provided, and the CPU 62 calculates that a specific combustion mode has passed for a predetermined time. A rich spike may be performed.
[0034]
From the CPU 62, operation signals are sent to the ETC device 25, the EGR valve 71, and the injectors 41 and 42, respectively. The ROM 63 stores target torque map data based on the engine speed and the accelerator opening, calculates the target torque based on the engine speed and the accelerator opening, and whether there is a request for a rich spike. Based on the temperature of the engine coolant, a combustion mode setting that sends an operation signal to the ETC device 25, the EGR valve 71, and both the injectors 41 and 42 and sets the combustion mode to any one of the above-described modes A to E. The CPU 62 has a unit 62a. The ROM 63 stores map data of the target boost pressure based on the engine speed and the accelerator opening, and the CPU 62 sets the target boost pressure of the map data read according to the driving situation. An operation signal is sent to the supercharging pressure solenoid 37.
[0035]
An input signal and an output signal for the CPU 62 are connected via an input interface and an output interface (not shown).
[0036]
A solenoid operation detection signal 72 for detecting an operation state of the supercharging pressure solenoid 37 and a battery voltage signal 73 for detecting a battery voltage are respectively sent to the CPU 62, and the supercharging pressure solenoid 37 is transmitted by these signals. The CPU 62 has a supercharging pressure solenoid failure determination unit 62b that determines whether it is normal or has failed. When it is determined by these signals that the supercharging pressure solenoid 37 is out of order, the combustion mode A, that is, uniform combustion is set regardless of the operation state.
[0037]
Signals from an idling switch 74 for detecting whether or not the engine is idling and the pressure sensor 38 are input to the CPU 62. These signals are detected by the crank angle sensor 9. The CPU 62 has a pressure sensor failure determination unit 62c for determining whether the pressure sensor 38 is normal or failed based on the engine speed.
[0038]
FIG. 3 is a circuit diagram showing an example of a supercharging pressure solenoid control unit 75 that sends an operation signal to the supercharging pressure solenoid 37. An on / off signal is sent from the CPU 62 to the base terminal of the transistor 76 that turns the supercharging pressure solenoid 37 on and off. It is supposed to be. The collector terminal connected to the supercharging pressure solenoid 37 is also connected to the CPU 62, and a solenoid operation detection signal 72 is sent to the CPU 62.
[0039]
Therefore, when an ON signal having a predetermined pulse width is output from the CPU 62 to the transistor 76, by detecting whether or not the solenoid operation detection signal 72 is output correspondingly, the boost pressure solenoid 37 is detected. It can be determined whether or not the device is out of order. Reference numeral 77 denotes a battery.
[0040]
FIG. 4 is a diagram showing the pressure characteristics of the pressure sensor 38. The pressure sensor 38 outputs a voltage corresponding to the pressure. As shown in FIG. 1, the pressure sensor 38 is switched by a switching valve 39a between a state communicating with the intake passage and a state communicating with the atmosphere. In this way, whether the pressure sensor 38 is normal or malfunctioning is determined by detecting the atmospheric pressure by the pressure sensor 38.
[0041]
FIG. 5 is a main flowchart showing a combustion mode setting procedure for setting the combustion mode to any one of the modes described above in accordance with the operating status. In step S1, a signal indicating the operating status such as the engine speed is fetched. In step S2, it is determined whether the supercharging pressure solenoid 37 is normal or faulty. In step S3, it is determined whether the pressure sensor 38 is normal or faulty. Based on the detection result, one of combustion modes A to E is set in step S4.
[0042]
FIG. 6 is a flowchart showing a subroutine for determining the failure of the supercharging pressure solenoid in step S2 shown in FIG. 5. In step S10, it is determined whether or not the voltage of the battery 77 is equal to or higher than a predetermined voltage value. The predetermined voltage value is set to about 11V, for example. The battery voltage is judged because it is not possible to accurately determine or diagnose a failure if the battery voltage is lowered in the determination described below. If the battery voltage is equal to or lower than a predetermined voltage value, the failure determination is made. Do not do.
[0043]
In step S11, it is determined whether or not a signal for operating the boost pressure solenoid 37 is sent from the CPU 62. In step S12, a solenoid operation detection signal 72 is detected to determine whether or not the boost pressure solenoid 37 is normal. Is judged. If determined to be normal, the boost pressure solenoid failure flag is cleared in step S13, and if determined to be failure, the boost pressure solenoid failure flag is set in step S14.
[0044]
When the supercharging pressure solenoid control unit has the structure shown in FIG. 3, it is determined in step S11 whether or not a signal is output to the base terminal of the transistor 76, and in step S12, the collector terminal is at the LOW level. Or whether it is HIGH level. That is, if the boost pressure solenoid 37 is normal, the collector terminal becomes LOW when a signal is turned on from the CPU 62 to the base terminal, and if it is malfunctioning, the collector terminal is HIGH even if the signal is turned on. By detecting this, it is possible to determine whether the boost pressure solenoid 37 is normal or malfunctioning.
[0045]
When no pulse is supplied to the supercharging pressure solenoid 37, it is determined in step S11 that no signal is output to the base of the transistor 76. In this case, in step S15, as in step S12, Determine whether the collector terminal is LOW level or HIGH level. That is, if the boost pressure solenoid 37 is normal, the collector terminal is at a high level when the signal is off from the CPU 62 to the base terminal, and if it is out of order, the collector terminal is off even if the signal is off at the base terminal. Since the terminal is at the LOW level, it is possible to determine whether the boost pressure solenoid 37 is normal or faulty by detecting this.
[0046]
FIG. 7 is a flowchart showing a subroutine for determining the failure of the pressure sensor in step S3. The pressure sensor 38 detects the atmospheric pressure every predetermined time by operating the switching solenoid 39, and the atmospheric pressure does not change suddenly and greatly, so that the pressure sensor 38 is equal to or higher than the set pressure value before and after the predetermined time elapses. When the difference is detected, it can be determined that the pressure sensor 38 is malfunctioning. The set pressure value is set to about 200 mmHg.
[0047]
Therefore, in step S20, the latest atmospheric pressure detection value ALT_nAnd the previous atmospheric pressure detection value ALT_n-1It is determined whether or not the difference is greater than the set pressure value. If the pressure difference is equal to or less than the set pressure value (200 mmHg), the process proceeds to step S21 to determine whether the switching solenoid 39 is on or off. When the switching solenoid 39 is turned on, the pressure sensor 38 detects the atmospheric pressure, and when it is turned off, it detects the absolute pressure of the intake air in the intake passage.
[0048]
As shown in FIG. 4, the pressure of the intake air that can be detected by the pressure sensor 38 is usually sufficient if it is an absolute pressure of about 100 to 1900 mmHg, and the corresponding sensor voltage is 1 to 4.5 V. It has become. Therefore, when a voltage exceeding this range is output from the pressure sensor, it can be determined that the pressure sensor 38 is out of order. Therefore, in step S22, it is determined whether or not a predetermined minimum voltage value, for example, 0.2 V or less, and in step S23, it is determined whether or not a predetermined maximum voltage value, for example, 4.9 V or more. To do. If it is determined in step S23 that the sensor output voltage is within the predetermined range, step S24 is executed.
[0049]
In step S24, it is determined whether or not the idling switch 74 is turned on. When the switch 74 is turned on, in step S25, the engine speed becomes the minimum idling speed, for example, 500 rpm or more. Judge whether or not. If the engine speed is equal to or higher than the rotational speed, it is determined in step S26 whether or not the output voltage of the pressure sensor 38 is an idling determination voltage. For example, if the engine speed is about 500 rpm, the negative pressure of the intake air is usually about −500 mmHg, and when the atmospheric pressure is 760 mmHg, the absolute pressure is about 260 mmHg. The output voltage of the sensor 38 is 2.1 V or less. Therefore, in step S26, the idling determination voltage is set to 2.5 V, and if the sensor output voltage when the engine is idling is 2.5 V or less, it is determined that the pressure sensor 38 is normal.
[0050]
If it is determined in step S26 that the pressure sensor 38 is normal, the output characteristics of the pressure sensor 38 are also normal, and the operation of the switching solenoid 39 is also normal. In step S27, the pressure sensor failure flag To clear. When it is determined in step S24 that the idling switch 74 is not turned on, that is, when the engine is not idling, and in step S25, it is determined that the idling speed is equal to or less than the minimum idling speed. When it is determined, failure determination of the pressure sensor 38 is not performed.
[0051]
When it is determined in steps S22 and 23 that the output voltage of the pressure sensor 38 is outside the predetermined range, and in step S26, the output voltage of the pressure sensor during idling is higher than the idling determination voltage of 2.5V. Sometimes, step S28 is executed and the pressure sensor failure flag is set.
[0052]
Similarly, in step S20, if the pressure difference between the previous atmospheric pressure detection value and the latest atmospheric pressure detection value is greater than or equal to the set pressure value, step S28 is executed assuming that the pressure sensor 38 has failed.
[0053]
If it is determined in step S21 that the switching solenoid is at atmospheric pressure, in step S29, whether the output voltage of the pressure sensor is a predetermined minimum voltage value, for example, 0.2 V or less, as in step S22. If a voltage smaller than the minimum voltage value is output, it is determined that the pressure sensor 38 is out of order and the process proceeds to step S28. If the voltage is larger than the minimum voltage value, the process proceeds to step S30. .
[0054]
In step S30, it is determined whether or not the sensor output voltage is larger than the atmospheric pressure upper limit voltage value. As the atmospheric pressure upper limit voltage value, a voltage value higher than the voltage of 2.1 V corresponding to the normal atmospheric pressure value of 760 mmHg, that is, a voltage value corresponding to a predetermined pressure value equal to or higher than atmospheric pressure is set. If the voltage value is lower than that, step S27 is executed assuming that the pressure sensor is normal, and if a voltage higher than that is output, it is determined that the pressure sensor 38 is faulty, and step S28 is executed. Is executed.
[0055]
FIG. 8 is a flowchart showing a subroutine for setting the combustion mode in step S4 shown in FIG. 5. In step S31, it is determined whether or not the boost pressure solenoid failure flag is set. In step S32, the sensor failure flag is set. It is determined whether it is set. If all of the supercharging pressure solenoid 37, the pressure sensor 38, and the switching solenoid 39 are normal, the flag is determined to be cleared in these steps, and the combustion mode switching mode is executed in step S33. Any one of the two combustion modes is set according to the operation state.
[0056]
On the other hand, if it is determined in step S31, 32 that at least one of the supercharging pressure solenoid 37, the pressure sensor 38, and the switching solenoid 39 has failed, the combustion mode at the time of failure is set in step S34, and EGR is set. Uniform stoichiometric combustion (combustion mode A) is set in a state in which is not operated. As a combustion mode at the time of this failure, it may be set to be uniform rich if it is not stratified combustion.
[0057]
As described above, when at least one of the supercharging pressure solenoid 37, the pressure sensor 38, and the switching solenoid 39 fails, these troubles are caused by adjusting the intake air amount and the fuel supply amount in correspondence with the uniform combustion. Sometimes combustion can be performed stably. 6 and 7 is executed in 50 ms, and one routine in FIG. 8 is executed in 10 ms.
[0058]
It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, as the supercharger, the turbocharger 31 is used in the illustrated case, but a supercharger may be used.
[0059]
【The invention's effect】
In the present invention, when any one of the supercharging pressure solenoid that adjusts the supercharging pressure and the pressure sensor that detects the pressure in the intake passage occurs, the combustion mode is controlled to be uniform combustion. Therefore, combustion can be stabilized even when these failures occur.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an internal combustion engine with a supercharger according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a control circuit for controlling the combustion mode of the engine.
FIG. 3 is a circuit diagram showing a supercharging pressure solenoid control unit;
FIG. 4 is a diagram showing pressure characteristics of a pressure sensor.
FIG. 5 is a main flowchart showing an engine control procedure;
FIG. 6 is a flowchart illustrating a subroutine for determining a failure of a supercharging pressure solenoid.
FIG. 7 is a flowchart showing a subroutine for pressure sensor failure determination.
FIG. 8 is a flowchart showing a combustion mode setting subroutine.
[Explanation of symbols]
25 Electronic throttle control device (ETC device)
25a Throttle valve
31 Turbocharger
35 Wastegate valve
37 Supercharging pressure solenoid
38 Pressure sensor
39 Switching solenoid
41 In-cylinder injector
42 In-cylinder injector
67 Accelerator position sensor
62a Combustion form setting section
62b Supercharging pressure solenoid failure determination unit
62c Pressure sensor failure determination unit

Claims (6)

An internal combustion engine with a supercharger having a supercharger for supercharging air sucked into a combustion chamber,
A supercharging pressure solenoid for adjusting a supercharging pressure in an intake passage communicating with the combustion chamber;
Supercharging pressure solenoid failure determining means for determining failure of the supercharging pressure solenoid;
An in-cylinder injector that directly injects fuel into the combustion chamber;
An in-cylinder injector for injecting fuel into the intake passage;
Combustion that determines the combustion mode in the combustion chamber according to the operating conditions, adjusts the opening of the throttle valve and the fuel injection amount, and sets the combustion mode to uniform combustion when the boost pressure solenoid fails And an internal combustion engine with a supercharger. An internal combustion engine with a supercharger having a supercharger for supercharging air sucked into a combustion chamber,
A pressure sensor for detecting an absolute pressure and an atmospheric pressure of intake air in an intake passage communicating with the combustion chamber;
Pressure sensor failure determination means for determining failure of the pressure sensor ;
An in-cylinder injector that directly injects fuel into the combustion chamber;
An in-cylinder injector for injecting fuel into the intake passage;
Combustion determining means that determines the combustion mode in the combustion chamber according to the operating condition, adjusts the opening of the throttle valve and the fuel injection amount, and sets the combustion mode to uniform combustion when a failure of the pressure sensor occurs And an internal combustion engine with a supercharger. An internal combustion engine with a supercharger having a supercharger for supercharging air sucked into a combustion chamber,
A pressure sensor for detecting an absolute pressure and an atmospheric pressure of intake air in an intake passage communicating with the combustion chamber;
A supercharging pressure solenoid for adjusting the supercharging pressure in the intake passage;
Pressure sensor failure determination means for determining failure of the pressure sensor ;
Supercharging pressure solenoid failure determining means for determining failure of the supercharging pressure solenoid;
An in-cylinder injector that directly injects fuel into the combustion chamber;
An in-cylinder injector for injecting fuel into the intake passage;
The combustion mode in the combustion chamber is determined in accordance with the operating conditions, the throttle valve opening and the fuel injection amount are adjusted, and the combustion mode when any of the pressure sensor and the supercharging pressure solenoid fails An internal combustion engine with a supercharger comprising combustion determining means for setting the combustion to uniform combustion. The supercharging pressure solenoid failure determining means detects an operation signal for operating the supercharging pressure solenoid and determines whether or not the signal is normal, thereby determining the failure of the supercharging pressure solenoid. The internal combustion engine with a supercharger according to claim 1 or 3. The pressure sensor failure determination means compares the difference between the latest atmospheric pressure detection value detected by the pressure sensor and the previous atmospheric pressure detection value with a predetermined value to perform failure diagnosis of the pressure sensor. An internal combustion engine with a supercharger according to claim 2 or 3. 4. The internal combustion engine with a supercharger according to claim 2, wherein the pressure sensor failure determination means performs failure determination of the pressure sensor by comparing an output voltage of the pressure sensor with a predetermined value.

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