JPH10299553A - Control device for internal combustion engine with electronic throttle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a given running performance of a vehicle by providing a limp-formed valve for trouble shooting of an electronic throttle control device, even at trouble time of this trouble-time-use valve, relating to a control device for an internal combustion engine with electronic throttle control device. SOLUTION: This internal combustion engine provided with an electronic throttle control device 150 electrically driving a throttle valve 15 is provided with a limp-formed valve 14 arranged bypassing the throttle valve 15 for trouble time of the electronic throttle control device 150 and a trouble detection means 70 detecting a sticking trouble of the limp-formed valve 14. When opening sticking trouble of the limp-formed valve 14 is detected by the trouble detection means 70, an output of the internal combustion engine is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine provided with an electronic throttle control device (drive-by-wire) and a limp home valve provided in case of a failure of the electronic throttle control device. The present invention relates to a control device for an internal combustion engine with an electronic throttle control device, which is suitable for use in a direct injection internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in an engine of an automobile or the like, a drive-by-wire (hereinafter, referred to as a D) is used to connect an accelerator pedal and a throttle valve by an electric signal.
BW) has been developed. In such a DBW, the accelerator pedal and the throttle valve are not mechanically connected, and the virtual accelerator opening is calculated by a computer based on various parameters other than the operation amount of the accelerator pedal (accelerator opening). (Pseudo accelerator opening) can be set and the throttle valve can be controlled accordingly, and is also called an electronic throttle control device.

Therefore, for example, during idling operation in which the accelerator pedal is not operated (ie, the accelerator opening is smaller than a predetermined small value), the idle speed can be controlled while finely adjusting the throttle valve. A pseudo accelerator opening is set by correcting the accelerator opening (operating by the driver) in accordance with the state and the operating state of the engine, and a good feeling engine operation is realized by throttle control based on this. You can also.

On the other hand, in recent years, an internal combustion engine (generally, a gasoline engine) in which spark ignition is performed by a spark plug,
2. Description of the Related Art A spark ignition type direct injection internal combustion engine (hereinafter referred to as an engine) that injects fuel directly into a cylinder has been put to practical use. In such an engine, it is possible to achieve both an improvement in the fuel efficiency and an improvement in the output performance of the engine by utilizing the characteristic that the fuel injection timing can be freely controlled and the formation state of the air-fuel mixture can be freely controlled.

That is, in the spark ignition type direct injection type engine, the fuel is injected in the compression stroke, so that the fuel is extremely lean (ie, the air-fuel ratio is much larger than the stoichiometric air-fuel ratio) due to the stratified combustion. (Super-lean combustion operation), and a super-lean operation mode (compression stroke injection mode) is provided as a combustion mode, so that a significant improvement in fuel consumption rate can be realized.

In a spark ignition type direct injection engine, naturally, a premix combustion operation for injecting fuel mainly in an intake stroke can also be performed. In this case, fuel is directly injected into a combustion chamber (in a cylinder). Thus, most of the fuel injected in each combustion cycle can be surely burned in the combustion cycle, so that the engine output can be improved.

[0007] Such a premixed combustion operation is also a lean operation mode (an intake lean operation mode) in which the operation is performed in a fuel-lean state (that is, the air-fuel ratio is larger than the stoichiometric air-fuel ratio), though not as much as the super-lean operation mode. ), A stoichiometric operation mode in which feedback control is performed based on O ₂ sensor information or the like so that the air-fuel ratio becomes a stoichiometric air-fuel ratio (stoichiometric feedback operation mode), and a state where fuel is rich (that is,
An enriched operation mode (open loop mode) in which operation is performed at an air-fuel ratio smaller than the stoichiometric air-fuel ratio) can be set as the combustion mode.

In general, when the required output to the engine is small, that is, when the engine speed is low and the load is small, the fuel efficiency is improved in the compression lean operation mode, and the engine speed and the engine load are further increased. In accordance with this, the intake lean operation mode, the stoichiometric operation mode, and the enrich operation mode are selected in this order.

By the way, in the case of the super-lean combustion operation (compression lean operation), it is necessary to supply more air to the combustion chamber in order to increase the air-fuel ratio. That is, since the operation is performed in a region where the accelerator pedal depression amount (accelerator opening) is small, the required air-fuel ratio cannot be satisfied with the throttle valve opening corresponding to the accelerator opening.

In view of this, an air bypass passage is provided which bypasses an intake passage provided with a throttle valve, and an electronic control valve (air bypass valve) is interposed in the air bypass passage so that the throttle valve opening corresponding to the accelerator opening can be adjusted. A technique has also been developed in which when the intake becomes insufficient, the air bypass valve is opened according to the required amount of air to supply air.

[0011]

By the way, it is conceivable to apply the above-mentioned drive-by-wire (DBW) to the above-described spark ignition type direct injection type engine. That is, D
In the BW, the throttle valve opening can be controlled without corresponding to the accelerator opening, so that a larger amount of air can be supplied to the combustion chamber than the amount corresponding to the accelerator opening. During the compression lean operation, the required amount of air can be supplied to the combustion chamber even if the accelerator opening is small.

However, when such a DBW is adopted, not only the in-cylinder injection type engine but also a countermeasure against a failure of the DBW should be prepared. As a countermeasure against the DBW failure, a failure valve (for example, also referred to as a limp home valve) is provided in a bypass passage parallel to the intake adjustment system using the DBW so that intake can be reliably performed even when the DBW fails. Conceivable.

However, when the failure valve (limp home valve) is stuck open, the amount of intake air becomes larger than in the normal state, and the output does not decrease even when the driver does not request torque, so that the output is stable. However, there is a problem that it is not possible to secure the improved running performance. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and provides a failure valve (limp home valve) to cope with a failure of an electronic throttle control device. It is an object of the present invention to provide a control device for an internal combustion engine with an electronic throttle control device, which can ensure a certain running performance of a vehicle at times.

[0014]

According to the present invention, there is provided a control device for an internal combustion engine with an electronic throttle control device according to the present invention, wherein the control device includes an electronic throttle control device for electrically driving a throttle valve. A limp home valve provided to bypass the throttle valve in the event of a failure of the electronic throttle control device, failure detection means for detecting a stuck open failure of the limp home valve, and When the home valve is stuck open, a process for reducing the output of the internal combustion engine is performed.

According to a second aspect of the present invention, a control device for an internal combustion engine with an electronic throttle control device includes an electronic throttle control device for electrically driving a throttle valve, and selects a lean mode in which combustion is performed at a high air-fuel ratio. A limp home valve provided to bypass the throttle valve in the event of a failure of the electronic throttle control device, failure detection means for detecting a stuck open failure of the limp home valve, When the detecting means detects that the limp home valve is stuck open, the lean mode is selected.

According to a third aspect of the present invention, there is provided a control device for an internal combustion engine with an electronic throttle control device according to the second aspect, wherein the internal combustion engine is a direct injection internal combustion engine capable of performing fuel injection in a compression stroke. So, as the lean mode,
It is characterized in that it has a compression stroke injection lean mode in which combustion is performed at an extremely high air-fuel ratio, and selects the compression stroke injection lean mode when the failure detecting means detects that the limp home valve is stuck open.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 5 show a control device for an internal combustion engine with an electronic throttle control device according to an embodiment of the present invention. Yes, and will be described with reference to these figures. [Overall Description of Engine Mounted on Vehicle] First, an engine (internal combustion engine) according to the present embodiment is a spark ignition type cylinder injection type internal combustion engine (hereinafter also referred to as a cylinder injection engine). This will be described with reference to FIG.

In FIG. 2, 1 is an engine body, 2 is an intake passage, 3 is a throttle valve installation portion, and 4 is an air cleaner. The intake passage 2 has a configuration in which an intake pipe 7, a throttle body 5, a surge tank 8, and an intake manifold 9 are connected in this order from the upstream side. The throttle body 5 is provided with an electronically controlled electronically controlled throttle valve (throttle valve) 15. The electronically controlled throttle valve 15 is a throttle control computer (throttle controller, also referred to herein as ETV) which will be described later. The opening is controlled through 160. The target opening of the throttle valve (target throttle opening) is determined by an engine control computer (engine ECU) 16 described later.
The depression amount of the accelerator pedal 50 (accelerator opening) detected by the accelerator position sensor (APS1) 51A
And according to the engine operating state.

An electronic throttle control device (ie, drive-by-wire (DBW)) 150 (see FIG. 1) includes the electronic control throttle valve 15, the engine ECU 16, the throttle controller 160, and the like. In parallel with such an electronically controlled throttle valve 15, a limp home valve device (LHV)
12 are equipped. The LHV 12 is for supplying air so that combustion of the engine is established when an electronically controlled throttle valve (described later) fails (closed failure). The LHV 12 is located upstream of the surge tank 8 so as to bypass the electronically controlled throttle valve 15. The LHV body 14 is a linear solenoid (not shown) controlled by an engine control computer (engine ECU) 16 to be described later. It is designed to be driven.

Reference numeral 17 denotes an exhaust passage, and reference numeral 18 denotes a combustion chamber. Openings of the intake passage 2 and the exhaust passage 17 to the combustion chamber 18, that is, the intake port 2A and the exhaust port 17A are provided with an intake valve 19 and an exhaust valve. 20 are equipped. In addition, 2
Reference numeral 1 denotes a fuel injection valve (injector). In the present embodiment, the injector 21 is arranged so as to directly inject fuel into the combustion chamber 18.

Reference numeral 22 denotes a fuel tank, and 23A to 23E.
Is a fuel supply passage, 24 is a low-pressure fuel pump, 25 is a high-pressure fuel pump, 26 is a low-pressure regulator, 27 is a high-pressure regulator, and 28 is a delivery pipe. The fuel in the fuel tank 22 is driven by the low-pressure fuel pump 24 and further. The fuel supply passage 23 is pressurized by a high-pressure fuel pump 25 and maintained at a predetermined high pressure.
A, 23B and the delivery pipe 28 supply the fuel to the injector 21. At this time, the fuel pressure discharged from the low-pressure fuel pump 24 is controlled by the low-pressure regulator 2.
6, the fuel pressure which is increased by the high pressure fuel pump 25 and guided to the delivery pipe 28 is adjusted by the high pressure regulator 2
The pressure is adjusted at 7.

Reference numeral 29 designates a part of the exhaust gas for the intake passage 2
An exhaust gas recirculation passage (EGR passage) that recirculates to
An EGR valve (exhaust gas amount adjusting means) for adjusting the recirculation amount of the exhaust gas through the GR 29, 32 is a flow path for reducing blow-by gas, 33 is a valve for active ventilation of the crankcase, and 34 is a canister. And 35 is an exhaust gas purifying catalyst (here, a three-way catalyst).

By the way, as shown in FIG.
In the CU 16, drive control of the injector 21, drive control of an ignition coil for operating an unillustrated spark plug,
In addition to the control of the opening of the EGR valve, the control of the fuel pressure by the high-pressure regulator 27, and the like, the control of the LHV 12 is performed according to the operating state or the failure state of the engine. Further, the throttle controller 160 controls opening and closing of the electronically controlled throttle valve 15 in accordance with an accelerator command of a driver, an operating state of the engine, and a failure state.

Therefore, as shown in FIG. 2, the engine ECU 16 has a first accelerator position sensor (APS).
1) 51A, air flow sensor (not shown), intake air temperature sensor 36, throttle position sensor (TPS) 37B for detecting throttle opening, idle switch 38,
An air conditioner switch (not shown), a shift position sensor (not shown), a vehicle speed sensor (not shown), a power steering switch (not shown) for detecting an operating state of the power steering,
Starter switch (not shown), first cylinder detection sensor 4
0, the crank angle sensor 41, water temperature sensor 42 for detecting a cooling water temperature of the engine, from the O ₂ sensor 43 that detects an oxygen concentration in the exhaust gas, the detection signal is adapted to be transmitted. Since the engine speed (engine speed) can be calculated based on the crank angle sensor 41, the crank angle sensor 41 is referred to as an engine speed sensor for convenience.

The throttle controller 160 has an accelerator position sensor (A) as shown in FIG.
PS) 51B, throttle position sensor (TPS)
A detection signal is transmitted from 37A or the like. The engine ECU 16 and the throttle controller 160 are configured to exchange information with each other by communication.

Further, the engine includes an automatic transmission (A
T) 170 and an automatic transmission controller (AT controller) 171 for controlling the automatic transmission 170 are attached, and the engine ECU 16 and the AT controller 1
Also, it is configured such that information can be exchanged with the communication device 71 by communication. The engine also has an auto cruise function, and the throttle controller 160 performs throttle opening control and the like according to input information related to auto cruise.

By the way, in such an engine, the operating modes include a late lean combustion operating mode (compression stroke injection mode), a first lean burning operating mode, a stoichiometric feedback operating burning operating mode, and an open loop burning operating mode. One of these modes is selected according to the operating state of the engine (that is, the engine speed and the engine load), the running state of the vehicle, and the like.

Of these, the latter lean combustion operation mode is as follows:
This is a mode in which fuel injection is performed at a stage very close to the ignition timing, such as the latter half of the compression stroke, and stratified combustion is performed while collecting fuel near the spark plug to make it partially rich and overall lean. This is an ultra-lean combustion mode in which saving operation can be performed while ensuring ignitability and combustion stability. In this embodiment, the total air-fuel ratio is set to a region of about 24 or more, and the leanest combustion can be realized. However, the total air-fuel ratio is lower than that of the present embodiment (for example, when the total air-fuel ratio is about (A range of about 23 or more), or may be set to a higher area than in the present embodiment.

The first lean burn operation mode is also the lean burn mode. In this mode, the fuel is injected before the second lean burn operation mode (mainly, the intake stroke), and the fuel is premixed and the whole fuel is mixed. Is a mode in which economy operation is performed while obtaining a certain amount of output while ensuring ignitability and combustion stability while keeping the air-fuel ratio leaner than the stoichiometric air-fuel ratio. Here, the region of the first period lean combustion operation mode is set to a region where the total air-fuel ratio is about 24 or less and equal to or more than the stoichiometric air-fuel ratio.

In the stoichiometric feedback combustion operation mode, a sufficient engine output can be efficiently obtained based on the output of the O ₂ sensor while maintaining the air-fuel ratio in the stoichiometric state. In this mode, premixed combustion based on fuel injection in the intake stroke is performed. Also,
In the open-loop combustion operation mode, combustion is performed at stoichiometric or rich air-fuel ratio by open-loop control so that a sufficient output can be obtained during acceleration or starting.
In this mode, premixed combustion based on fuel injection in the intake stroke is performed.

Each of these operation modes corresponds to an engine ECU (to be described later) according to the engine speed and the engine load.
In the low-speed, low-load state, the latter lean combustion operation mode is usually selected. When the engine speed and the engine load increase, the latter lean combustion operation mode and the stoichiometric combustion operation mode are selected. Open loop mode (enrich combustion operation mode) when the engine speed and engine load increase in order.
Can be switched to

The engine ECU 16 performs various controls after selecting the operation mode in this manner. Focusing on the throttle valve control, in the late lean combustion operation mode in which fuel is injected during the compression stroke and the air-fuel ratio is extremely large, In order to achieve the target air-fuel ratio, there is a shortage of air at the throttle valve opening according to the accelerator opening, so the target opening (pseudo target opening) is much larger than the throttle valve opening according to the accelerator opening. ) Is set and the throttle valve opening is controlled based on this.
In addition, even in the stoichiometric feedback combustion operation mode and the open loop combustion operation mode, there is a case where the air becomes insufficient at the throttle valve opening corresponding to the accelerator opening,
In this case, a target opening (pseudo target opening) that is appropriately larger than the throttle valve opening corresponding to the accelerator opening is set, and the throttle valve opening is controlled based on the target opening. . [Explanation of the intake control system] Here, the electronic throttle control device (DBW) 150 and the LHV related to the control device of the present invention.
12 control systems (ie, limp home valve control device) 1
20. These control systems are configured as shown in FIG.

That is, the electronically controlled throttle valve 15 constituting the DBW 150 is provided with a butterfly valve 151 interposed in the intake passage 5A in the throttle body 5 and a shaft 152 supporting the butterfly valve 151, and is provided with the butterfly valve 151. Return spring 15 for applying biasing force for closing
3, an electric motor (throttle actuator) 154 that rotationally drives the shaft 152, and a gear mechanism 155 interposed between the actuator 154 and the shaft 152.

The shaft 152 has a butterfly valve 15
A first throttle position sensor (TPS1) 37A and a second throttle position sensor (TPS2) are additionally provided as the throttle position sensor 37 for detecting the opening degree (throttle valve opening degree) of No. 1. As described above, the present apparatus is provided with the two throttle position sensors (TPS1, TPS2) 37A, 37B, which are the throttle position sensors 37A, 37B.
This is provided when a failure occurs in 7B.

The DBW 150 includes the electronically controlled throttle valve 15 and the electronically controlled throttle valve 1.
The engine ECU 16 is configured to set a target opening of the fifth ECU 5 and a throttle controller 160 that controls the operation of the actuator 154 based on the target opening set by the engine ECU 16 to adjust the throttle valve opening.

For this reason, as shown in FIG.
The CU 16 has a target opening setting section 16A, and the throttle controller 160 has a throttle opening feedback control section 160A. FIG. 3 is a control block diagram focusing on the throttle control.
As shown in FIG.
6A includes a first accelerator position sensor (APS).
1) a function 16a for setting a target engine torque from the detection information from 51A and the engine speed obtained from the detection result of the crank angle sensor 41 (see FIG. 2); A function 16b for performing atmospheric pressure correction, a function 16c for performing correction relating to an air conditioner, an electric load, and the like, and a function 16d for setting a target throttle opening from the corrected target engine torque and engine speed are provided.

The target opening setting section 16A further includes a second
16e for setting the dashpot control opening based on the detection information from the throttle position sensor (TPS2) 37B, and the idle speed control opening according to the engine coolant temperature information detected by the water temperature sensor (WTS). And a function 16g for selecting the maximum value from among these set openings. The selected maximum set opening is set as the target opening of the throttle valve, and the throttle controller 160 is provided with the function 16f. Output.

The throttle opening feedback control section 160A of the throttle controller 160 determines the motor drive current in accordance with the throttle valve target opening output from the engine ECU 16, and controls the actuator (also called throttle control servo) 154. The driving is controlled. At this time, a first throttle position sensor (TPS1) is provided in the throttle controller 160.
The throttle valve is feedback-controlled in accordance with the throttle valve opening (actual opening) detected at 37A.

In this apparatus, as shown in FIG. 1, the throttle position sensors (TPS1, TPS1,
2) As in the case of 37A, 37B, the accelerator position sensor 51 is also the first accelerator position sensor (A
PS1) 51A and a second accelerator position sensor (A
PS2) 51B are also provided in the event of a failure.

The detection signal of the first accelerator position sensor (APS1) 51A is input to the engine ECU 16 and used for setting the target throttle valve opening. The second accelerator position sensor (APS2) 51A
The detection signal of B is input to the throttle controller 160, and when the first accelerator position sensor 51A fails, the detection signal of the second accelerator position sensor 51B is transmitted from the throttle controller 160 to the engine ECU 16 through communication, and the throttle valve target It is used to set the opening.

As for the throttle position sensor,
First throttle position sensor (TPS1) 37A
Is input to the throttle controller 160 and used for feedback control of the throttle valve.
Second throttle position sensor (TPS2) 37B
Is input to the engine ECU 16 and is used for the above-described dashpot control and the like. When the first throttle position sensor 37A fails, the detection signal of the second throttle position sensor 37B is transmitted from the engine ECU 16 by communication. Throttle controller 1
The control signal is transmitted to the throttle valve 60 and used for feedback control of the throttle valve.

On the other hand, the limp home valve device 12 is provided with a bypass provided in parallel with the intake passage 5A in the throttle body 5 (ie, between the upstream side and the downstream side of the butterfly valve 151 of the electronically controlled throttle valve 15). Passage 13
The LHV main body 14 and the L
A linear solenoid (not shown) that opens and closes the HV body 14 and an engine ECU 16 that controls the operation of the linear solenoid are configured. A control system (a limp home valve control device) 120 includes a linear solenoid and the engine ECU 16. You.

The limp home valve device 12 includes a DBW1
In order to cope with the failure of 50, the present apparatus is designed to perform various failure determinations in the engine ECU 16 and the throttle controller 160 as a measure against the failure of the DBW 150. For the failure determination, corresponding processing is performed by using, for example, the limp home valve device 12.

As shown in FIG. 1, the power supply circuit from the battery 61 to the throttle controller 160 includes a power supply relay
The engine ECU 16 can be turned on and off as needed. Also, 180
This is a warning light that lights during limp home processing. here,
Each failure determination process will be described. This failure determination processing is performed by the engine ECU 16 and the throttle controller 1.
The determination is performed by the failure determination means (failure detection means) 70 provided on the basis of various types of detection information and control information. Specifically, the following determination processing is performed.

A. Position Feedback Failure First, a process of determining a failure (position feedback failure) in which the opening degree (position) of the electronically controlled throttle valve 15 cannot be adjusted as instructed will be described.
The position feedback failure includes a valve system fixation (including a fully closed fixation) and a motor output open failure. When a position feedback failure signal is received, it is determined that a failure has occurred.

However, the ignition switch is on. The motor relay is on, or a communication error from the engine ECU 16 to the throttle controller 160 has occurred. Battery voltage Vb is equal to or higher than a predetermined value. Engine E from throttle controller 160
No communication abnormality to the CU 16 has occurred. This failure determination is performed when all of the failure determination preconditions described above are satisfied.

One of the position feedback failures is the sticking of the electronically controlled throttle valve 15. In this case, the first throttle position sensor (APS)
1) The opening of the electronically controlled throttle valve 15 fixed at 37A can be detected. Therefore, based on the opening information, if the throttle valve 15 is stuck at the first predetermined opening degree or more (valve opening fixation), an opening fixation corresponding process (valve opening fixation failure process) is performed, and the throttle valve 15 is moved to the second position. If it is fixed below a predetermined opening (valve-closed-fixed), a closed-fixed process (valve-closed-fixed fail process) is performed.

The following processing is performed in the opening fixation processing (valve opening fixation failure processing). LHV12 is turned off (closed) to restrict the amount of intake air
And The fuel injection mode is limited to the compression lean mode (the forced compression lean mode). The fuel supply to some cylinders (for example, three cylinders for a six-cylinder engine) is stopped (partial cylinder fuel cut).

The EGR control is stopped (EGR cut). When the engine speed Ne is within a predetermined high rotation range (Ne ≧ 30)
(00 rpm), the fuel supply is stopped (fuel cut) for all cylinders. Of the auxiliary devices driven by the engine, those that do not adversely affect the operation of the engine due to the stop are stopped (here, the air conditioner is stopped).

As the valve closing sticking failure processing, in order to perform stable combustion even with a small intake air amount, the latter lean combustion operation mode or the earlier lean combustion operation mode included in the lean combustion mode is selected as the operation mode. Is performed to prohibit the operation from being performed.
That is, as the valve closing sticking failure processing, processing for switching the operation mode to the stoichiometric air-fuel ratio mode (stoichiometric feedback operation combustion operation mode, open loop combustion operation mode) is performed.

In addition, when a valve failure (including valve closing) occurs other than when the valve is stuck open, it is difficult to secure the intake air volume through the throttle valve. Limp home processing is performed to secure the intake air by utilizing the above. B. Motor faults Motor faults include motor ground fault and motor short-to-power (overcurrent detection). When a motor output ground fault or short-to-power fault signal is received, a failure is determined. However, the motor relay is on. No communication abnormality from the throttle controller 160 to the engine ECU 16 has occurred. This failure determination is performed when all of the failure determination preconditions described above are satisfied. When such a motor failure occurs, a limp home mode process described later is performed.

C. TPS Failure There are first and second two TPSs 37A and 37B in the throttle position sensor.
The throttle position sensor (TPS1) 37A has a failure due to the open or short circuit of the current circuit and a linearity defect, and the second throttle position sensor (TPS2) 37B has a characteristic abnormality and a failure due to the open or short circuit of the current circuit. When each failure signal is received, it is determined that a failure has occurred.

However, in this failure determination, the ignition switch is turned on. Throttle controller 1
No communication abnormality from 60 to engine ECU 16 has occurred. Is performed when all the preconditions for failure determination are satisfied. Then, when the first throttle position sensor (TPS1) 37A fails, the feedback control of the throttle valve is hindered, so that a process for limiting the operating range of the engine is performed. Further, when the first throttle position sensor (TPS1) 37A fails, the second throttle position sensor (TPS2) 37
B has failed or a communication error (engine EC
If there is a communication error from U16 to the throttle controller 160), a limp home process is performed.

D. Communication Failure Communication is performed between the engine ECU 16 and the throttle controller 160.
Communication abnormality from U16 to throttle controller 160 and engine ECU from throttle controller 160
There is a communication error with No. 16.

Regarding a communication abnormality from the engine ECU 16 to the throttle controller 160, when the throttle controller 160 receives a communication failure signal from the engine ECU 16, it is determined that a failure has occurred. However, in this failure determination, the battery voltage Vb is equal to or higher than a predetermined value.
From the throttle controller 160 to the engine ECU 16
No communication error has occurred with. This is performed when all of the failure determination preconditions are satisfied.

At the time of this communication failure, the engine ECU 16
Since the throttle valve 160 cannot capture the target opening of the throttle valve set in the step (1) and the intake air amount cannot be properly controlled, the following processing is performed. Lean operation prohibition process Cruise control control prohibition process Fuel cut process at high engine speed (for example, Ne ≧ 3000 rpm) ・ Throttle controller 160 to engine ECU 1
Regarding the communication abnormality to No. 6, if any of the following conditions is satisfied, it is determined that a failure has occurred.

There is a checksum error. There is an overrun framing error. Communication has not been completed for a predetermined time (for example, for 25 msec). However, in this failure determination, the battery voltage Vb is equal to or higher than a predetermined value. The cruising switch is off. This is performed when all of the failure determination preconditions are satisfied.

Even when this communication failure occurs, the engine ECU 16
Does not take in a control signal or the like from the throttle controller 160, and it is more likely that the intake air amount control cannot be appropriately performed. Therefore, the following process is performed. Transmission of communication failure to throttle controller 160 Lean operation prohibition process Cruise control control prohibition process Fuel cut process when engine is running at high speed (for example, Ne ≧ 3000 rpm) When the brake is depressed, the command target opening of throttle valve 15 from engine ECU 16 is clipped at the upper limit .

E. Throttle controller failure (ETV
Failure) Regarding the failure of the throttle controller 160, if all of the following conditions are satisfied, or
If all of the conditions are satisfied, it is determined that a failure has occurred. The ignition switch is on.

The second accelerator position sensor (APS)
2) 51B and second throttle position sensor (TP
S2) There is no abnormality in 37B. Engine ECU 16 to throttle controller 16
Communication error to 0 has occurred. | ( _VAPS2 ) / 2- (5v- _VTPS2 ) | _{≥1v The} ignition switch is on.

A second accelerator position sensor (APS)
2) 51B and second throttle position sensor (TP
S2) There is no abnormality in 37B. Engine ECU1 from throttle controller 160
Communication error to 6 has occurred. | (Engine ECU command opening voltage−V _TPS2 ) | ≧ 1v If such a failure of the throttle controller 160 is determined, a limp home process is performed.

F. APS Failure The accelerator position sensor has first and second two APSs 51A and 51B, and these first and second APSs 51A and 51B are used.
Accelerator position sensor (APS1, APS2) 5
1A and 51B include a failure due to a short circuit in the current circuit, a failure due to the opening of the sensor GND, a failure due to the opening of the current circuit, a failure due to the short circuit to the sensor GND, and a characteristic abnormality.・ Second accelerator position sensor (APS2) 51B
The faults due to the short circuit of the current circuit and the faults due to the open of the sensor GND are based on the premise that the condition that there is no communication error and the first accelerator position sensor (APS1) 51A has no error is satisfied. It is determined when both conditions are satisfied.

Second accelerator position sensor 51B
_Is greater than or _equal to a predetermined value V1 (for example, V1 =
_Assuming 4.5 v, V _APS2 ≧ 4.5 v). Output value V of first accelerator position sensor 51A
_APS1 is within a predetermined range (e.g., 0.2 v ≦ V _APS1 ≦
2.5v).・ Second accelerator position sensor (APS2) 51B
The failure due to the opening of the current circuit and the failure due to the sensor GND short are caused by the second accelerator position sensor 51.
B output value V _APS2 is equal to or less than a predetermined value V2 (for example, V2
= 0.2v, it is determined when V _APS2 <0.2v).・ First accelerator position sensor (APS1) 51A
The faults due to the short circuit of the current circuit and the faults due to the open of the sensor GND are based on the assumption that the condition that there is no communication error and the second accelerator position sensor (APS2) 51B has no error is satisfied. It is determined when both conditions are satisfied.

First accelerator position sensor 51A
The output value V _APS1 is a predetermined value or more V3 (for example, V2 =
Assuming that 4.5 V, V _APS1 ≧ 4.5 V). Output value V of second accelerator position sensor 51B
_APS2 is within a predetermined area (for example, 0.2v ≦ V _APS2 ≦
2.5v).・ First accelerator position sensor (APS1) 51A
The failure due to the opening of the current circuit and the failure due to the sensor GND short are caused by the first accelerator position sensor 51.
A output value V _{APS1 of A} is equal to or less than a predetermined value V4 (for example, V4
= When 0.2 v, it determines when V _APS1 <a 0.2 v). The characteristic abnormality of the accelerator position sensor is determined when V _APS2 ≧ 1.1 v on the assumption that the idle switch is turned on (that is, during idle operation).

When the second accelerator position sensor 51B fails, the following processing is performed. V _APS = V _APS1 / 2 Set lean operation prohibition process Cruise control control prohibition process Engine output upper limit clipping process However, the second accelerator position sensor (APS2)
After detecting the failure of the 51B, the throttle controller 160
When a communication error from the engine to the engine ECU 16 occurs, a limp home process is performed. Further, when the first accelerator position sensor 51A fails, the following processing is performed.

Setting V _APS = V _APS2 / 2 Lean operation prohibition processing Cruise control control prohibition processing Engine output upper limit clip processing However, the second accelerator position sensor (APS
2) If 51B has failed, limp home processing is performed.

When the characteristic of the accelerator position sensor is abnormal, the following processing is performed. V _APS = V _APS1 / 2 Set lean operation prohibition process Cruise control control prohibition process Engine output upper limit clipping process However, the first accelerator position sensor (APS
1) If 51A has failed, limp home processing is performed.

G. LHV failure For LHV12 failure, if the LHV solenoid is off and the terminal voltage Lo is detected, LHV1
Judge as 2 failures. This determination is made when the LHV 12 is energized in spite of the operating state in which the LHV 12 should not be turned on (for example, during normal operation, when the throttle valve is open and the ABW is not double failed). Thus, it can be measured that the LHV 12 is fixed in the open state.

When the LHV 12 fails, the following processing is performed. Forced compression lean operation. That is, the engine operation mode is limited to the late lean combustion operation mode (compression stroke injection mode), and the engine output is suppressed. When the engine is running at high speed (for example, Ne ≧ 3000 rpm), the fuel is cut. Cut EGR.

The engine speed feedback control of the idle speed control is prohibited. By the way, in the limp home process, the LHV 12 is operated so that air can be supplied to each combustion chamber of the engine. However, the LHV body 14 of the LHV 12 is normally controlled on and off to operate the LHV 12. Is LHV
The main body 14 is turned on.

Therefore, during limp home processing, the intake air amount is not adjusted, the engine output itself is not adjusted, and the vehicle speed control is set to be performed exclusively by the driver's brake operation. For this reason, the amount of intake air during operation of the LHV 12 is suppressed so as not to make the engine output excessive. That is, when the LHV 12 is operated, a constant amount of running output is obtained, and the driver operates the brake to take an amount of air that does not hinder deceleration or stopping.

The limp home processing specifically performs the following processing. A: Fuel cut processing 1) At the time of forward running the second accelerator position sensor (APS2) 51B
Is less than or equal to a predetermined value [(5v-V _APS2 )> 1.5v]
In the case of, fuel injection is performed in all cylinders.

The second accelerator position sensor (AP
S2) The output value of 51B is equal to or more than a predetermined value [(5v-V _APS2 )
≦ 1.5v], the fuel injection is cut for some cylinders (for example, three cylinders for all six cylinders). Second accelerator position sensor (APS2) 51B
, The fuel injection of some of the cylinders (for example, three cylinders for all six cylinders) is cut off.

When the brake pedal is depressed, fuel injection is cut for some of the cylinders (for example, three cylinders for all six cylinders). 2) Backward traveling Fuel injection cut is performed for some cylinders (for example, three cylinders for all six cylinders). B: Turn off the motor relay.

C: Turn on the LHV 12 [However, when the brake is depressed (when the brake switch is turned on), the duty of the LHV 12 is controlled at 5 Hz for a predetermined time (for example, 2 seconds). D: Lean operation is prohibited. E: Cruise control control prohibition processing F: Engine speed feedback control is prohibited.

G: The warning lamp 180 is turned on. H: Once in limp home mode, normal recovery does not occur until the ignition switch is turned off. In each fail process, the lean mode is prohibited. However, since the lean mode is a mode established based on high-precision throttle control, stable combustion may be impaired in the lean mode when a TPS failure occurs. In order to avoid this, the lean mode is prohibited.

Next, a failure determination process in the case of a position feedback failure due to sticking of the electronically controlled throttle valve 15 will be described. For this failure determination process,
As shown in FIG. 1, the throttle controller 160 is provided with a failure determination means 70, which determines whether or not a failure has occurred due to the sticking of the electronically controlled throttle valve 15. Processing for switching the operation mode is performed according to the result of the determination.

The failure determination means 70 reads the target opening set based on the detection information from the accelerator position sensor 51A, and the electronically controlled throttle valve detected by the second throttle position sensor (TPS2) 37B. The target opening and the opening of the electronic control throttle valve 15 are compared with each other, and an opening difference equal to or more than a predetermined opening (for example, 1 °) is determined over a predetermined time (for example, 500 ms). If the continuation is continued, it is determined that a failure due to the sticking of the electronically controlled throttle valve 15 has occurred.

The electronically controlled throttle valve detected by the second throttle position sensor (TPS2) 37B despite the fact that the target opening set based on the detection information from the accelerator position sensor 51A is small. If the opening degree of No. 15 does not decrease (that is, if it remains in a large opening state larger than the first predetermined opening degree), it is determined that the valve is open, and conversely, based on the detection information from the accelerator position sensor 51A. The electronic control throttle valve 15 detected by the second throttle position sensor (TPS2) 37B does not increase (in other words, the second predetermined opening degree) even though the target opening degree set in advance is large. (When the small opening degree is smaller than the degree), it is determined that the valve is closed.

If the electronic control throttle valve 15 remains at or above the first predetermined opening and it is determined that the valve is stuck open, the above-described opening stuck handling process (valve opening stuck fail process) is performed. And the throttle valve 15
Is kept at or below the second predetermined opening degree, and if it is determined that the valve is closed and fixed, a closed-fixing process (valve-closed-failure process) is performed.

By the way, in the case of a valve failure other than this open fixation (full open fixation), the limp home process is performed. In the limp home process, as described above, the accelerator opening is set to the predetermined opening during forward running. If so, fuel injection is performed for all cylinders (all cylinder injection). If the accelerator opening is equal to or less than the predetermined opening, fuel injection for some cylinders is stopped (partial cylinder injection cut).

That is, when a valve failure occurs, when the accelerator opening is small, that is, when the driver does not request engine torque, not only in the operating region but also in some cylinders (here, three cylinders out of six cylinders). When the fuel injection is stopped to reduce the engine output and the accelerator opening is large, that is, when the driver requests the engine torque, the fuel injection is not stopped for some cylinders, that is, for all cylinders. The engine output is ensured by performing fuel injection. Such a control function of appropriately stopping the fuel injection and reducing the engine output is referred to as output reduction means (not shown).

As described above, this output reduction means always stops fuel injection in some cylinders (here, three cylinders out of six cylinders) at the time of retreat to lower the engine output, and reduces the engine output during retreat. The output can be reliably reduced. It should be noted that even if it is determined that no failure has occurred in the failure determination processing in the case of such a position feedback failure regarding the electronically controlled throttle valve 15, the APS 51 as the accelerator opening detection means is determined.
A and 51B may fail, but in this case, since the adjustment of the intake air amount cannot be performed accurately, the combustion becomes unstable when the late lean combustion operation mode included in the lean combustion mode is selected. It is conceivable that the driver may feel uneasy.

For this reason, in the control device for an internal combustion engine according to the present embodiment, the above-mentioned (see “F. APS failure”)
Thus, a failure determination process in the case of an APS failure is performed. Note that, for such a failure determination process, the throttle controller 160 is provided with an accelerator opening failure determination unit (not shown).
It is determined whether or not B is out of order.
The APS5 is determined by the accelerator opening failure determination means.
When it is determined that 1A and 51B are out of order, the adjustment of the intake air amount cannot be performed accurately.
With W, the electronic control throttle valve 15 is driven so that the opening degree becomes a predetermined small opening degree state, and the operation mode is switched to the stoichiometric air-fuel ratio mode.

Since the control device of the internal combustion engine with the electronic throttle control device according to one embodiment of the present invention is configured as described above, the failure of the intake control system, that is, the electronic throttle control device (DBW) 150 and For the failure of the LHV12 system, processing is performed, for example, as shown in FIG. That is, first, processing related to LHV failure determination is performed by the LHV failure determination routine (step A10). The determination of the LHV failure determines whether the LHV solenoid is off and whether the terminal voltage Lo is detected. If the LHV solenoid is off and the terminal voltage Lo is detected, it is a LHV failure. Is determined. In this case, after the determination in step A20, engine output suppression processing is performed in step A30. Specifically, the following processes are performed.

The operation mode is forcibly set to the latter lean combustion operation mode (compression stroke injection mode) to suppress the engine output. When the engine rotation speed Ne reaches a predetermined rotation speed (for example, 3000 r
pm), cut fuel (stop fuel supply)
To reduce the engine output. EGR is cut (stopped) and stable combustion is prioritized over exhaust gas purification.

Regarding the idle speed control, the engine speed feedback control is prohibited and the stable combustion is prioritized. In the event of an LHV failure, it is predicted that the LHV 12 is stuck in an open state, so that air is supplied not only from the air supplied through the throttle valve 15 but also from the bypass passage 13 having the valve body 14 of the LHV 12. Therefore, if the air-fuel ratio is controlled to a constant target,
Since the fuel supply amount is also increased, the engine output is increased particularly at the time of deceleration, stop and start, and the output becomes excessive against the driver's will, which is not convenient.

On the other hand, in the present apparatus, since the engine output is suppressed by setting the forced compression lean and by cutting the fuel when the engine speed increases, the engine output does not become excessive. The vehicle can be operated to a required point (for example, a repair shop or the like), and the burden on the driver in the event of a failure can be reduced.

On the other hand, if there is no LHV failure, step A
After the determination at 20, the process proceeds to step A40, where it is determined whether the APS fail flag Ffail ₁ is 1. The APS fail flag Ffail ₁ becomes _{1 when one} of the accelerator position sensors (APS) 51A, 51B fails, and becomes 0 otherwise. here,
If the flag Ffail ₁ is 1, the process proceeds to the APS double failure determination routine of step A80. If the flag Ffail ₁ is not 1, the process proceeds to the APS failure determination routine of step A50.

In the APS failure determination routine of step A50, the first accelerator position sensor (APS1) 5
1A, second accelerator position sensor (APS2) 5
For each of 1B, a failure due to a short circuit in the current circuit, a failure due to the open of the sensor GND, a failure due to the open of the current circuit, a failure due to the short circuit to the sensor GND, and abnormal characteristics are performed as described above.

When the APS failure is determined, the process proceeds to step A80 via step A70, and the APS failure is a double failure, that is, the first and second accelerator position sensors (APS1, APS2) 51A, 51B. It is determined whether or not any of them has failed. If the APS is a double failure, the process proceeds to step A300 to perform limp home processing, and if the APS is not a double failure, that is, two APs
If only one of S is out of order, the process proceeds to step A90.

In step A90, it is determined whether or not the brake switch is on, that is, whether or not the brake operation is being performed. If the brake operation has been performed, the process proceeds to step A100, in which the throttle opening command value is clipped to a predetermined upper limit value to suppress the intake air amount, thereby suppressing the engine output. If the brake operation has not been performed, the process proceeds to step A120, and each failure process is performed according to the APS failure.

That is, when the second accelerator position sensor 51B fails, V _APS = V _APS1 / 2 is set.
Lean operation is prohibited, cruise control control is prohibited, and the engine output upper limit is clipped. However, the second accelerator position sensor (APS2) 51
If a communication error occurs from the throttle controller 160 to the engine ECU 16 after the failure of B is detected, a limp home process is performed.

When the first accelerator position sensor 51A fails, V _APS = V _APS2 / 2 is set, lean operation is prohibited, and cruise control control is prohibited.
Clip the engine output upper limit. However, if the second accelerator position sensor (APS2) 51B has already failed, the limp home process is performed. When the characteristic of the accelerator position sensor is abnormal, V _APS =
Set V _APS1 / 2 to prohibit lean operation, prohibit cruise control control, and clip the engine output upper limit. However, if the first accelerator position sensor (APS1) 51A has already failed, the limp home process is performed.

On the other hand, if it is not an APS failure, the process proceeds from step A60 to the ETV determination routine of step A130. In this ETV determination routine, a failure of the throttle controller is determined. When the ignition switch is turned on and the second accelerator position sensor (APS)
2) and second throttle position sensor (TPS2)
Is normal and there is a communication error from the engine ECU 16 to the throttle controller 160, and |
(V _APS2 ) / 2− (5v−V _TPS2 ) | ≧ 1v or the ignition switch is on,
There is no abnormality in the second accelerator position sensor (APS2) and the second throttle position sensor (TPS2)
Engine ECU1 from throttle controller 160
Communication error to the ECU 6 and | (Engine ECU
If the command opening voltage −V _TPS2 ) | ≧ 1 V, it is determined that the throttle controller has failed.

When the failure of the throttle controller is determined, the process proceeds to step A300 via step A140 to perform limp home processing. When the failure of the throttle controller is not determined, the process proceeds to a communication failure determination routine of step A150. In the communication failure determination routine, the communication failure is determined to be a communication abnormality from the engine ECU 16 to the throttle controller 160 and a communication abnormality from the throttle controller 160 to the engine ECU 16.

Regarding the communication abnormality from the engine ECU 16 to the throttle controller 160, when the battery voltage Vb is higher than a predetermined value and the throttle controller 16
The determination is made in a situation (zone) where no communication abnormality from 0 to the engine ECU 16 has occurred. When the throttle controller 160 receives a communication failure signal from the engine ECU 16, it is determined that a failure has occurred.

The communication abnormality from the throttle controller 160 to the engine ECU 16 is determined in a situation (zone) where the battery voltage Vb is equal to or higher than a predetermined value and the cruising switch is off, and there is a checksum error, an overrun framing error. If the communication is not completed for a predetermined time (for example, for 25 msec), it is determined that a failure has occurred.

When such a communication failure is determined, the process proceeds to step A170 via step A160, and a communication failure handling process is performed. That is, when communication from the engine ECU 16 to the throttle controller 160 is abnormal, there is a high possibility that the intake air amount control cannot be appropriately performed.
Lean operation is prohibited, cruise control control is prohibited, and when the engine is running at high speed (for example, Ne ≧ 3000 rpm)
In m), a fuel cut is performed.

Further, when communication from the throttle controller 160 to the engine ECU 16 is abnormal, there is a high possibility that the intake air amount control cannot be performed properly. Therefore, a communication failure is transmitted to the throttle controller 160 to prohibit lean operation, and cruise control is performed. Control is prohibited and the engine is rotated at a high speed (for example, Ne ≧ 3000 rpm).
m), the fuel is cut, and when the brake is depressed,
The upper limit of the command target opening of the throttle valve from the engine ECU 16 is clipped.

If a communication failure is not determined, step A
After step 160, the process proceeds to a motor failure determination routine of step A180. In the motor failure determination routine, when the motor relay is on and a communication fault from the throttle controller 160 to the engine ECU 16 has not occurred (a zone), and when a ground fault or short-to-power fault signal of the motor output is received, It is determined that the motor has failed.

At the time of this motor failure determination, step A1
After 90, the process proceeds to step A300 to perform a limp home process. If no motor failure is determined, the process proceeds to a TPS failure determination routine of step A200. In the TPS failure determination routine, the ignition switch is turned on, and the throttle controller 160
Under the situation (zone) that communication abnormality to CU16 has not occurred, when each failure signal is received,
Judge as failure. The throttle controller 160
The first throttle position sensor (TPS1) 37A used for feedback control by
There is a failure due to the open or short circuit of the current circuit and a linearity failure, and the second throttle position sensor (TPS2) 37B has a characteristic abnormality and a failure due to the open or short circuit of the current circuit.

At step A210, TPS1 and TP are determined based on the result of the TPS failure determination routine.
It is determined whether any one of S2 and S2 has failed. Here, if one of TPS1 and TPS2 has failed, the process proceeds to step A220 and TPS1 and TPS2
It is determined whether both PS2 and PS2 have failed.

If both TPS1 and TPS2 have failed, the process proceeds to step A300 to perform limp home processing, otherwise (ie, TPS1 and TPS2).
If only one of them has failed), the process proceeds to step A230 to perform lean mode prohibition processing. In the lean mode prohibition process, the lean mode is a mode that is established based on high-precision throttle control. Therefore, when the TPS fails, stable combustion may be impaired in the lean mode. In order to avoid this, the lean mode is prohibited.

On the other hand, the throttle position sensor (TP
If none of S) has failed, step S210
, The position feedback failure determination routine of step S240 (POS F / B failure determination routine)
Proceed to. In the position feedback failure determination routine, the failure of the position feedback, that is, the sticking of the valve system (including the fully closed sticking) and the motor output open are determined. This determination is made when the ignition switch is turned on and the motor relay is turned off. The throttle controller 1 is turned on or
60 communication error has occurred and the battery voltage Vb
Is greater than or equal to a predetermined value, and a failure is determined when a position feedback failure signal is received in a situation (zone) in which communication abnormality from the throttle controller 160 to the engine ECU 16 has not occurred.

If the position feedback failure is not determined, the failure processing is not performed (return) through step A250. However, if the position feedback failure is determined, the process proceeds to step A260 via step A250 and the second throttle It is determined whether or not the valve opening degree V _TPS2 is equal to or greater than a predetermined value K1 (K1: a value close to full valve opening). Here, if the second throttle valve opening _VTPS2 is equal to or _larger than the predetermined value K1, the process proceeds to step A280, and a valve opening fixed fail process is performed.

If it is determined in step A260 that the second throttle valve opening V _TPS2 is not equal to or greater than the predetermined value K1, step A
_Proceeding to 270, it is determined whether the second throttle valve opening _VTPS2 is equal to or less than a predetermined value K2 (K2: a value close to fully closing the valve). Here, if the second throttle valve opening _VTPS2 is equal to or _smaller than the predetermined value K2, the process proceeds to step A290 to perform a valve closing fixed fail process.

Also, the second throttle valve opening V
_{If TPS2} is a value between the predetermined values K1 and K2, the process proceeds to step A300 to perform limp home processing. In the valve opening fixed fail process in step A280, the LHV 12 is turned off (closed) to limit the intake air amount, the fuel injection mode is limited to the compression lean mode (the forced compression lean mode is set), and some cylinders (for example, The fuel supply to three cylinders in the case of a six-cylinder engine is stopped (partial cylinder fuel cut), the EGR control is stopped (EGR cut), and the engine speed Ne is within a predetermined high speed region (Ne ≧ 3000).
(rpm), the fuel supply is stopped (fuel cut) for all cylinders, and the operation of the auxiliary equipment driven by the engine that does not adversely affect the engine operation due to the stop is stopped (here, the air conditioner is turned off). Stop).

As described above, in the present control device, when the throttle valve 15 is stuck at a large opening state equal to or larger than the predetermined opening degree, the late lean combustion operation mode is selected,
For example, stopping the fuel injection of a predetermined number of cylinders and lowering the output of the engine more reliably, and reliably avoiding a situation in which excessive output is output even though the output of the driver is not requested. Thus, there is an advantage that stable running according to the driver's request can be ensured.

Further, when it is determined that the throttle valve 15 is stuck in a large opening state equal to or larger than a predetermined opening degree, the load on the auxiliary equipment of the engine is reduced to stabilize the combustion in the lean combustion mode. There is also an advantage that stable driving can be ensured while preventing the driver from feeling uneasy due to output fluctuations. For other valve failures (including when the valve is closed and locked), the above-described limp home process is performed to secure the intake air using the LHV 12.

In the limp home process, from the viewpoint of valve failure, during forward running, fuel injection is performed in all cylinders when the accelerator opening is equal to or more than a predetermined opening (all cylinder injection), and when the accelerator opening is equal to or less than the predetermined opening. Stop fuel injection in some cylinders (cut off injection in some cylinders). Thereby, when the driver does not request the engine torque, the fuel injection to some cylinders (here, three cylinders out of six cylinders) is stopped to reduce the engine output. Does not stop fuel injection in some cylinders,
That is, by injecting fuel into all cylinders and securing the engine output, the driver's output request intention can be reflected in the engine output.

Also, at the time of retreat, fuel injection of some cylinders (here, three of six cylinders) is always stopped to lower the engine output, so that the engine output at the time of retreat can be surely reduced. So that the output is not too large,
The driving operation at the time of retreat can be easily performed. That is, the drivability of the reverse operation can be improved.

If it is determined that the throttle valve 15 is stuck in a small opening state equal to or less than the predetermined opening degree, the lean burn mode is prohibited, so that the output of the engine is secured and the output of the driver is secured. There is also an advantage that it is possible to avoid a state in which no output is output despite requesting the vehicle, and to ensure stable running according to the driver's request. Even when the failure of the electronic throttle control device is not determined by the failure determination means 70, if the accelerator opening degree failure determination means determines that the accelerator opening degree detection means has failed, the throttle valve opening is determined to be a predetermined value. Is controlled so as to be in the small opening degree state, and the selection of the lean combustion mode is prohibited. Therefore, there is an advantage that stable running can be ensured while preventing the driver from feeling uneasy due to uneasiness of combustion.

In the internal combustion engine of the present embodiment, when it is determined that the valve is stuck open, a process for handling an open fixation (failure process for opening the valve) is performed. Although the closed and fixed fail process is performed, only one of the processes may be performed. Then, the limp home process in step A300 is performed as shown in FIG.

That is, the lean operation mode is prohibited (step B10). That is, the lean operation mode that requires high-precision throttle control is avoided, and more stable combustion can be performed by the stoichiometric mode or the like. Next, the motor relay (power supply relay) 62 is turned off. As a result, power is not supplied to the throttle controller 160, the throttle valve control via the throttle controller 160 is not performed, and only the limp home valve 14 is controlled to adjust the intake air amount.

Then, whether or not the brake switch is on,
That is, it is determined whether a brake operation is being performed (step B30). If the brake switch is on, the limp home valve (LHV) 14 is duty-controlled for a predetermined time (for example, 2 seconds) (step B4).
0). That is, the limp home valve 14 is an on / off valve that is normally set to either on or off, but since it is an electromagnetic valve, duty control is also possible. Here, for example, the LHV 14 is set to have a duty of about 50%. By suppressing the opening degree of the bypass passage 1
3, the amount of air flowing through the intake manifold 3 can be reduced, so that the negative pressure of the intake manifold 9 can be increased to secure the master back negative pressure. Therefore, even during the limp home process, a sufficient master back negative pressure is obtained at the time of the brake operation, and the same braking force as in the normal state can be secured.

In this process, a predetermined time (two seconds in this case) at the start of the brake operation is sufficient, and when the predetermined time has elapsed, the duty control ends. By restricting the duty control of the limp home valve 14 within a predetermined time, the durability of the solenoid is also ensured. On the other hand, if the brake switch is off, the limp home valve (LHV) 14 is turned on (open) (step B50).

After the processes in steps B40 and B50 are performed, the process proceeds to step B60, and it is determined whether the vehicle is moving forward. If the vehicle is not moving forward, it means that the vehicle is moving backward, and always performs fuel cut of some cylinders (for example, fuel cut of three out of six cylinders).
The engine output is suppressed (step B110). As a result, it is possible to prevent the engine output from becoming excessive during parking and garage parking due to reverse travel.

If the vehicle is moving forward, step B
70, and a second accelerator position sensor (APS)
2) Whether the output value of 51B is equal to or more than a predetermined value [(5v-V
_APS2 )> 1.5v or (5v- _VAPS2 ) ≦ 1.5v
Is determined. Here, (5v−V _APS2 ) ≦ 1.5v
In step B110, the routine proceeds to step B110, in which fuel cut of some cylinders (for example, fuel cut of three cylinders out of six cylinders) is performed to suppress engine output. Also, (5v-V
_{If APS2} )> 1.5v, the routine proceeds to step B80, where it is determined whether or not the second accelerator position sensor (APS2) 51B has failed. This failure determination is performed as described above.

If APS2 has failed, step B1
Proceeding to 10, the fuel cut of some cylinders (for example, fuel cut of three cylinders out of six cylinders) is performed to suppress the engine output. If APS2 has not failed, step B
The routine proceeds to 90, where it is determined whether or not the brake switch is on, that is, whether or not a brake operation is being performed. Here, if the brake switch is ON, fuel cut of some cylinders (for example, fuel cut of three cylinders out of six cylinders) is performed to suppress engine output. If the brake switch is not on, the process proceeds to step B100, in which fuel injection is performed in all cylinders to secure output.

At the time of limp home processing, the warning light 1
Lighting of 80 is also performed. As described above, the limp home process is performed without any APS2 failure during forward running (that is, APS2).
2 is the state in which the driver's speed request intention can be grasped from the information), when the brake operation is not performed and the accelerator opening is equal to or more than a predetermined value, that is, when the driver requests the engine output, the fuel cut is performed. Although not performed, when the vehicle is traveling backward, when the APS2 fails, when the brake is operated, or when the accelerator opening is equal to or less than a predetermined value, the fuel cut of some of the cylinders (for example, That is, the fuel cut of the three cylinders is performed to suppress the engine output.

If the driver does not operate the brake, the driver can obtain the vehicle speed, and if the driver operates the brake, the driver can decelerate or stop the vehicle. Based on the operation information, the vehicle speed control reflecting the driver's intention can be performed at a certain level. Further, in the present control device, the fuel supply to some cylinders is stopped (fuel cut) to reduce the output. However, if the combustion is established, the fuel supply is stopped and the processing for reducing the fuel supply is performed. Is also good.

In the present control device, as a means for reducing the engine output, the mode is switched to the compression stroke injection mode, which is one of the lean combustion modes. However, the lean combustion mode is switched to the intake stroke injection mode (the former lean combustion operation mode). In the case of only the engine (1), the process for switching to the intake stroke injection mode may be performed. However, in the first lean combustion operation mode, combustion fluctuations are likely to occur. Therefore, it is preferable to select the second lean combustion operation mode (compression stroke injection mode) to reduce the engine output.

The reset condition for the failure determination is briefly described as an ignition key OFF, a battery OFF, and the like. The above-described control is repeated at the time of the most running, and when the DBW becomes normal at the re-determination. Returns to normal control. At this time, the contents of the fail are stored as fail information in a computer (EC
U or the controller), the DB can be used during vehicle inspection.
The W system can be rechecked.

Although the present control device has been described as a control device provided in a direct injection internal combustion engine, the present invention is not limited to this, and it is possible to select a lean burn mode and another mode (for example, a stoichiometric air-fuel ratio mode). Can also be applied as a control device for an internal combustion engine in which can be selected. Further, in the present embodiment, the present control device uses the automatic transmission as the transmission, but it is needless to say that the control device can be applied to a manual transmission.

[0126]

As described above in detail, according to the control device for an internal combustion engine with the electronic throttle control device according to the first aspect, the engine output is suppressed when the LHV is stuck open, so that the engine output becomes excessive. , The vehicle can be operated to a required point (for example, a repair shop or the like), and the burden on the driver in the event of a failure can be reduced.

According to the control device for an internal combustion engine with an electronic throttle control device according to the second aspect of the present invention, when the LHV is stuck in the open state, the engine output is suppressed by setting the engine to the lean mode. The vehicle can be operated to a required point (for example, a repair shop or the like) without becoming excessive, and the burden on the driver at the time of failure can be reduced more reliably.

According to the control device for an internal combustion engine with an electronic throttle control device according to the third aspect of the present invention, the engine output is suppressed by setting the compression lean mode when the LHV is stuck open. Does not become excessive, the vehicle can be operated to a required point (for example, a repair shop, etc.), and the burden on the driver at the time of failure can be reduced more reliably.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a main part of a control device of an internal combustion engine with an electronic throttle control device as one embodiment of the present invention.

FIG. 2 is a block diagram showing a control device of an internal combustion engine with an electronic throttle control device as one embodiment of the present invention.

FIG. 3 is a block diagram showing an intake control system of a control device for an internal combustion engine with an electronic throttle control device according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a process for preventing a failure in an intake control system of a control device of an internal combustion engine with an electronic throttle control device according to an embodiment of the present invention.

FIG. 5 is a flowchart showing a limp home process in a process for preventing a failure of the intake control system of the control device for the internal combustion engine with the electronic throttle control device as one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine main body 2 Intake passage 2A Intake port 3 Throttle valve installation part 4 Air cleaner 5 Throttle body 5A Intake passage in throttle body 7 Intake pipe 8 Surge tank 9 Intake manifold 12 Limp home valve device (LHV) 13 Bypass passage 14 Limp home valve Reference Signs List 15 electronic control throttle valve (throttle valve) 16 engine control computer (engine ECU) 16A target opening setting unit 17 exhaust passage 17A exhaust port 18 combustion chamber 19 intake valve 20 exhaust valve 21 fuel injection valve (injector) 22 fuel tank 23A 23E Fuel supply path 24 Low pressure fuel pump 25 High pressure fuel pump 26 Low pressure regulator 27 High pressure regulator 28 Delivery pipe 29 Exhaust gas recirculation passage (EGR passage) 30 EGR valve (Exhaust gas 32) Flow path for reducing blow-by gas 33 Valve for active ventilation of crankcase 34 Canister 35 Exhaust gas purification catalyst 36 Intake temperature sensor 37A First throttle position sensor (TPS)
1) 37B second throttle position sensor (TPS)
2) 38 idle switch 40 first cylinder detection sensor 41 crank angle sensor 42 water temperature sensor 43 O ₂ sensor 50 accelerator pedal 70 failure determination means (failure detection means) 51A first accelerator position sensor (APS1) 51A first accelerator position Sensor (APS2) 120 Limp home valve controller 150 Electronic throttle controller [drive-by-wire (DBW)] 151 Butterfly valve 152 Shaft supporting butterfly valve 153 Return spring 154 Electric motor (throttle actuator) 155 Gear mechanism 160 Throttle control computer ( Throttle controller) 160A Throttle opening feedback control section 170 Automatic transmission (AT) 171 Automatic transmission controller (AT controller) 180 Warning light

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Seiichi Inoue Mitsubishi Motors Corporation

Claims (3)

[Claims] 1. An internal combustion engine having an electronic throttle control device for electrically driving a throttle valve, a limp home valve provided to bypass the throttle valve in case of failure of the electronic throttle control device, Failure detecting means for detecting the stuck-open failure of the limp home valve; and performing processing for reducing the output of the internal combustion engine when the failure detecting means detects the stuck-open failure of the limp home valve. A control device for an internal combustion engine with an electronic throttle control device. 2. An internal combustion engine having an electronic throttle control device for electrically driving a throttle valve and capable of selecting a lean mode in which combustion is performed at a high air-fuel ratio. A limp home valve provided by bypassing the throttle valve, failure detection means for detecting an open fixation failure of the limp home valve, and when the failure detection means detects the open fixation failure of the limp home valve, A control device for an internal combustion engine with an electronic throttle control device, wherein a lean mode is selected. 3. The engine according to claim 1, wherein the internal combustion engine is a direct injection internal combustion engine capable of performing fuel injection during a compression stroke, and includes, as the lean mode, a compression stroke injection lean mode for performing combustion at an extremely high air-fuel ratio. 3. The control device for an internal combustion engine with an electronic throttle control device according to claim 2, wherein when the detection means detects that the limp home valve is stuck open, the compression stroke injection lean mode is selected.