JPH09209812A - Fuel injection control device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Problem] Even if an abnormality occurs in the throttle valve,
It is possible to achieve smooth evacuation traveling without causing combustion failure and sudden increase in output. SOLUTION: A fuel injection valve 11 is arranged in the vicinity of an inner wall surface of a cylinder head 4 near a first intake valve 6a and a second intake valve 6b, and fuel from the fuel injection valve 11 is directly supplied to a cylinder 1a.
Injected into. An electronically controlled throttle valve 23 is arranged in the intake duct 20, and when the throttle valve 23 is in an abnormal state, it is brought into a fully closed state by a spring. When an abnormality of the throttle valve 23 is detected by the electronic control unit (ECU) 30, and when the accelerator opening is equal to or less than a predetermined opening, the throttle opening is fixed and the operation by the stratified charge combustion is executed in principle. When the opening is larger than the predetermined opening, the throttle opening increases with an increase in the accelerator opening, the operation at the theoretical air-fuel ratio is executed, and the required output torque is secured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device for an internal combustion engine, and more particularly, to a fuel injection control for an internal combustion engine capable of performing stratified combustion and homogeneous combustion, such as a cylinder injection internal combustion engine. It relates to the device.

[0002]

2. Description of the Related Art In a conventionally used engine, fuel from a fuel injection valve is injected into an intake port, and a homogeneous mixture of fuel and air is supplied to a combustion chamber in advance. In such an engine, an intake passage is opened and closed by a throttle valve linked to an accelerator operation, and by this opening and closing, the amount of intake air supplied to a combustion chamber of the engine (consequently, a gas mixture in which fuel and air are homogeneously mixed). ) Is adjusted, thereby controlling the engine output.

[0003] However, in the technique based on the so-called homogeneous combustion described above, a large intake negative pressure is generated in accordance with the throttle operation of the throttle valve, and the pumping loss increases to lower the efficiency. On the other hand, by reducing the throttle of the throttle valve and supplying fuel directly to the combustion chamber, a combustible air-fuel mixture is present in the vicinity of the spark plug, and the air-fuel ratio of that portion is increased,
There is known a so-called "stratified combustion" technique for improving ignitability.

For example, in the technique disclosed in Japanese Examined Patent Publication No. 6-39923, stratified charge combustion is achieved by injecting fuel directly into the combustion chamber and appropriately controlling an electronically controlled throttle valve. There is. That is, in the low / medium load and low / medium rotation regions, stratified combustion is executed by suppressing the throttle throttle and causing the combustible mixture to exist near the ignition plug. At this time, the electronically controlled throttle valve is controlled to be maintained at a predetermined opening. Further, in the high-load / high-speed region, homogeneous combustion is executed instead of the above-described stratified combustion. For this reason, combustion is executed according to the load and rotation at that time, and in particular, fuel consumption is improved by "stratified combustion".

[0005]

However, the above prior art has the following problems. That is, when the electronically controlled throttle valve fails for some reason (mechanical cause, electrical cause), the air amount cannot be controlled properly, and normal operation by the above control becomes impossible. Therefore, in such a case, it is necessary to perform fail safe.

However, for example, in a system in which the throttle valve is fully closed when the throttle valve fails, the intake air amount becomes almost "0". Therefore, although combustion that is sufficient for idling can be ensured, it is not possible to obtain an output higher than a predetermined value, which may make it difficult to evacuate.

On the other hand, in a system in which the throttle valve is fully opened upon failure, the intake air amount is always the maximum. In this case, if no restriction is applied to the fuel injection, combustion failure will occur or the output will suddenly increase, making it difficult to evacuate.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to prevent combustion even if an abnormality occurs in the throttle valve, and to cause a rapid increase in output. Another object of the present invention is to provide a fuel injection control device for an internal combustion engine, which is capable of achieving smooth evacuation traveling in response to a driver's request.

[0009]

In order to achieve the above object, in the invention described in claim 1, as shown in FIG. 1, in the cylinder M2 of the internal combustion engine M1 in order to perform stratified combustion and homogeneous combustion. A fuel injection means M3 for injecting fuel into the cylinder M and an intake passage M4 of the internal combustion engine M1.
2, a throttle valve M5 for adjusting the amount of intake air supplied to the internal combustion engine 2, an operating state detecting means M6 for detecting a required operating state of the internal combustion engine M1, and a detection result of the operating state detecting means M6. And a fuel injection control unit M7 for controlling fuel injection injected from the fuel injection unit M3 into the cylinder M2, the fuel injection control unit M7 including the throttle valve M5. When abnormality is detected in the throttle valve M5 by the abnormality detecting means M8 for detecting the abnormality of the fuel consumption, and the abnormality detecting means M8 detects the abnormality in the fuel amount according to the accelerator opening detected by the operating state detecting means M6. The gist of the invention is to include an injection mode changing means M9 for changing the injection mode of the fuel injected from the injection means M3.

Further, in the invention described in claim 2, in the fuel injection control device for the internal combustion engine according to claim 1, the injection mode changing means M9 is configured such that when the accelerator opening is smaller than a predetermined opening, The fuel injection means M3 is controlled to perform stratified combustion, and when the accelerator opening is larger than the predetermined opening, the fuel injection means M3 is controlled to perform combustion at a stoichiometric air-fuel ratio. I am trying.

Further, in the invention according to claim 3, in the fuel injection control device for the internal combustion engine according to claim 2, the throttle valve M5 is driven by an actuator, and the actuator is operated by the operation. The throttle opening control means controls the throttle opening based on the detection result of the state detecting means M6, and when the throttle opening is smaller than the predetermined opening when the throttle valve M5 itself is abnormal, the throttle opening is smaller than the predetermined opening. Is held at a position near the fully closed position, and when the accelerator opening is larger than the predetermined opening, the throttle opening is adjusted so as to increase as the accelerator opening increases. It is a summary.

[0012] In addition, in the invention described in claim 4, in the fuel injection control device for the internal combustion engine according to claim 3, the position near the fully closed position is a sufficient opening for idling the internal combustion engine. The point is that there is something.

In addition, in the invention according to claim 5, in the fuel injection control device for the internal combustion engine according to claim 3 or 4, it is possible to secure a negative pressure for braking at the position near the fully closed position. The gist is that the opening is sufficiently large.

(Operation) According to the first aspect of the invention, the fuel is injected from the fuel injection means M3 into the cylinder M2 of the internal combustion engine M1, and the fuel-air mixture explodes in the cylinder M2.
Output is obtained by combustion. In addition, stratified combustion and homogeneous combustion may be performed depending on the form of injection. The throttle valve M5 provided in the intake passage M4 of the internal combustion engine M1 is opened and closed to change the opening area in the intake passage M4, thereby adjusting the intake air amount supplied to the cylinder M2. It Further, the operating state detecting means M6 detects the requested operating state of the internal combustion engine M1. Then, based on the detection result, by the fuel injection control means M7,
The amount of fuel injected from the fuel injection means M3 into the cylinder M2 is controlled.

In the present invention, the abnormality detecting means M8 detects the abnormality of the throttle valve M5. When the abnormality detection means M8 detects an abnormality in the throttle valve M5, the injection mode of the fuel injected from the fuel injection means M3 is changed by the injection mode changing means M9 according to the accelerator opening. Therefore, the throttle valve M5
Even if an abnormality occurs in the vehicle, the driver's request is reflected in the fuel injection form, and the escape running becomes possible.

Further, in the invention described in claim 2, in addition to the operation of the invention described in claim 1, when the abnormality of the throttle valve M5 is detected by the abnormality detecting means M8, the accelerator opening degree is a predetermined opening degree. When it is smaller than the above, the injection mode changing means M9 controls the fuel injection means M3 to perform stratified charge combustion. Further, when the accelerator opening is larger than the predetermined opening, combustion is performed at the stoichiometric air-fuel ratio. Therefore, the driver's request is more accurately reflected in the fuel injection mode. For example, when the driver wants to perform the evacuation traveling, the accelerator pedal is depressed greatly to enable combustion at the stoichiometric air-fuel ratio, and the output required for the evacuation traveling can be secured.

Further, in the invention described in claim 3, in addition to the effect described in claim 2, the actuator is controlled by the throttle opening control means based on the detection result of the operating state detection means M6, and by this control. The throttle valve M5 is driven.

When the throttle valve M5 itself is in an abnormal state and the accelerator opening is smaller than the predetermined opening, the throttle opening is maintained at a position close to the fully closed position.
When the accelerator opening is larger than the predetermined opening, the throttle opening is adjusted to increase as the accelerator opening increases. Therefore, for example, when the driver wants to evacuate, the accelerator pedal is depressed so much that the throttle valve M5 is opened with an increase in the depression amount, and the intake air required for the theoretical air-fuel ratio is increased. The amount will be surely secured.

In addition, according to the invention described in claim 4, in addition to the operation of the invention described in claim 3, when the throttle valve M5 is abnormal and the accelerator opening is smaller than a predetermined opening, the throttle opening is opened. The degree is maintained at a position near the fully closed position, and the opening degree at this time is sufficient for idling the internal combustion engine. Therefore, even if an abnormality occurs, it is possible to secure a sufficient intake air amount to perform idling and prevent engine stall or the like from occurring.

In addition, in the invention described in claim 5, in addition to the operation of the invention described in claim 3 or 4, when the throttle valve M5 is abnormal and the accelerator opening is smaller than a predetermined opening, The throttle opening is maintained at a position near the fully closed position, but the opening at this time is sufficient to ensure a negative pressure for braking.
Therefore, sufficient braking performance can be ensured without separately using a means for generating a negative pressure for braking.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying a fuel injection control device for an internal combustion engine according to the present invention will be described below in detail with reference to the drawings.

FIG. 2 is a schematic configuration diagram showing a fuel injection control device of a direct injection type engine mounted on a vehicle in the present embodiment. The engine 1 as an internal combustion engine includes, for example, four cylinders 1a, and the combustion chamber structure of each of the cylinders 1a is shown in FIG. As shown in these figures,
The engine 1 has a piston in a cylinder block 2, and the piston reciprocates in the cylinder block 2. A cylinder head 4 is provided above the cylinder block 2.
Is provided, and a combustion chamber 5 is formed between the piston and the cylinder head 4. Further, in the present embodiment, four valves are arranged per cylinder 1a, and in the figure, the first intake valve 6a, the second intake valve 6b, the first intake port 7a, and the first intake port 7b in the figure. Two intake ports, a pair of exhaust valves as 8, and a pair of exhaust ports as 9 are shown.

As shown in FIG. 3, the first intake port 7a
Is composed of a helical intake port, and the second intake port 7
b consists of a straight port that extends almost straight.
In addition, an ignition plug 10 is disposed at the center of the inner wall surface of the cylinder head 4. Further, a fuel injection valve 11 is arranged near the inner wall surface of the cylinder head 4 near the first intake valve 6a and the second intake valve 6b. That is, in the present embodiment, the fuel from the fuel injection valve 11 is directly injected into the cylinder 1a. An ignition signal distributed by a distributor (not shown) is applied to the spark plug 10. The distributor synchronizes the high voltage output from the igniter 12 with the crank angle of the engine 1 and each spark plug 10
The ignition timing of each spark plug 10 is determined by the high voltage output timing from the igniter 12.

As shown in FIG. 2, the first intake port 7a and the second intake port 7b of each cylinder 1a are respectively connected via a first intake path 15a and a second intake path 15b formed in each intake manifold 15. Connected to the surge tank 16. A swirl control valve 17 is arranged in each second intake passage 15b. These swirl control valves 17 are connected to, for example, a step motor 19 via a common shaft 18. The step motor 19 is controlled based on an output signal from an electronic control unit (hereinafter simply referred to as “ECU”) 30 described later. Instead of the step motor 19,
What is controlled according to the negative pressure of the intake port of the engine 1 may be used.

The surge tank 16 includes an intake duct 20
Is connected to the air cleaner 21 via the
Inside, a throttle valve 23 that is opened and closed by a step motor 22 that is an actuator is arranged. That is, the throttle valve 23 of the present embodiment is of a so-called electronic control type. Basically, the throttle valve 23 is controlled to open and close by the step motor 22 being driven based on the output signal from the ECU 30. Is done. The specific configuration of the throttle valve 23 will be described later. By opening and closing the throttle valve 23, the amount of intake air introduced into the combustion chamber 5 through the intake duct 20 is adjusted. In the present embodiment, an intake passage is constituted by the intake duct 20, the surge tank 16, the first intake passage 15a, the second intake passage 15b, and the like. A throttle sensor 25 for detecting the opening (throttle opening TA) is provided near the throttle valve 23. An exhaust manifold 14 is connected to the exhaust port 9 of each cylinder. The exhaust gas after the combustion is exhaust manifold 1
The air is discharged to an exhaust duct (not shown) through the air duct 4.

Further, in the present embodiment, a known exhaust gas circulation (EGR) device 51 is provided. This EG
The R device 51 includes an EGR passage 5 as an exhaust gas circulation passage.
2 and an EGR valve 53 as an exhaust gas circulation valve provided midway in the passage 52. EGR passage 5
2 is an intake duct 20 on the downstream side of the throttle valve 23,
It is provided so as to communicate with the exhaust duct. The EGR valve 53 has a built-in valve seat, valve body, and step motor (all not shown). The opening degree of the EGR valve 53 fluctuates when the stepping motor intermittently displaces the valve body with respect to the valve seat. And EG
When the R valve 53 opens, a part of the exhaust gas discharged to the exhaust duct flows to the EGR passage 52. The exhaust gas flows to the intake duct 20 via the EGR valve 53. That is, a part of the exhaust gas is recirculated into the intake air-fuel mixture by the EGR device 51. At this time, the recirculation amount of the exhaust gas is adjusted by adjusting the opening degree of the EGR valve 53.

Next, the structure of the throttle valve 23 in the present embodiment will be described with reference to the schematic view of FIG. The valve body 23a of the throttle valve 23 is provided with the first spring 4
1 always biases in the fully closing direction. Further, when the opening degree of the throttle valve 23 is closed to near the fully closed position, the valve body 23a once comes into contact with the stopper 42. This stopper 42 is attached to the first wall 4
It is arranged so as to be able to reciprocate between the third wall 44 and the third wall 44, and is always urged by the second spring 45 so as to abut against the second wall 44. Then, the step motor 22
When there is no abnormality in the valve body 23a, the valve body 23a resists the biasing force of the first spring 41 and the second spring 45 by the driving force of the step motor 22 and the stopper 42 causes the first wall 43 to move.
It is possible to move from the fully closed position Q _min corresponding to the above to the fully open position (upper part of the figure).

Further, in the present embodiment, the throttle valve 23 is provided with a key 46. This key 46
Is mechanically connected to the accelerator pedal 24 via a third spring 47. The spring constant of the third spring 47 is larger than the spring constant of the second spring 45. Further, this key 46 is used for the accelerator pedal 24
When the depression amount (accelerator opening degree ACCP) is smaller than the predetermined opening degree α, the stopper 42 is held at the same position where it is in contact with the second wall 44. Then, when the accelerator opening ACCP exceeds the predetermined opening α, the key 46 moves to the third wall 48 against the urging force of the third spring 47 and the like, and the valve body accordingly. 23a can be moved (opened).

Therefore, as shown in FIGS. 5 and 7, an abnormality has occurred in the step motor 22 or the like (for example, it has stopped moving).
In this case, when the accelerator opening ACCP is smaller than the predetermined opening α, the valve body 23a is in contact with the stopper 42, and the throttle opening is maintained at the position Q ₀ near the fully closed position. On the other hand, as shown in FIGS. 5 and 8, when the accelerator opening ACCP exceeds the predetermined opening α, the valve body 23a is pressed by the key 46 as the accelerator opening ACCP increases. , The key 46 will be opened until it abuts against the third wall 48.

Now, as shown in FIG. 2, the above-mentioned ECU
Reference numeral 30 denotes a digital computer, which includes a RAM (random access memory) 32 and a ROM (read only memory) connected to each other via a bidirectional bus 31.
33, a CPU (central processing unit) 34 including a microprocessor, an input port 35, and an output port 36. In the present embodiment, the ECU 30 constitutes fuel injection control means, abnormality detection means, and injection mode changing means.

An accelerator sensor 26, which generates an output voltage proportional to the amount of depression of the accelerator pedal 24, is connected to the accelerator pedal 24, and the accelerator sensor 26 is connected to the accelerator sensor 26.
As a result, the accelerator opening ACCP is detected. The output voltage of the accelerator sensor 26 is input to the input port 35 via the AD converter 37.

The top dead center sensor 27 generates an output pulse when the first cylinder 1a reaches the intake top dead center, for example.
This output pulse is input to the input port 35. The crank angle sensor 28 has a crankshaft of 30 ° CA, for example.
An output pulse is generated each time the motor rotates, and the output pulse is input to the input port. In the CPU 34, the top dead center sensor 2
The engine speed NE is calculated (read) from the output pulse of 7 and the output pulse of the crank angle sensor 28.

Further, the rotation angle of the shaft 18 is detected by a swirl control valve sensor 29,
Thereby, the opening of the swirl control valve 17 is measured. The output of the swirl control valve sensor 29 is supplied to an input port 35 via an A / D converter 37.
Is input to

At the same time, the throttle sensor 25 detects the throttle opening TA. The output of the throttle sensor 25 is input to an input port 35 via an A / D converter 37.

In addition, in the present embodiment, an intake pressure sensor 61 for detecting the pressure in the surge tank 16 (intake pressure PiM) is provided. Further, a water temperature sensor 62 that detects the temperature of the cooling water of the engine 1 (cooling water temperature THW) is provided. The outputs of both sensors 61 and 62 are also A /
It is adapted to be input to the input port 35 via the D converter 37.

In the present embodiment, these throttle sensor 25, accelerator sensor 26, top dead center sensor 27,
The crank angle sensor 28, the swirl control valve sensor 29, the intake pressure sensor 61, the water temperature sensor 62 and the like constitute an operating state detecting means.

On the other hand, the output port 36 is connected to each of the fuel injection valves 11 and each of the step motors 1 via a corresponding drive circuit 38.
9, 22, the igniter 12 and the EGR valve 53 (step motor). Then, based on signals from the sensors 25 to 29, 61, and 62, the ECU 30 operates according to a control program stored in the ROM 33,
The fuel injection valve 11, the step motors 19 and 22, the igniter 12, the EGR valve 53 and the like are suitably controlled.

Next, a program relating to various controls according to the present embodiment in the fuel injection control device for an engine having the above-mentioned configuration will be described with reference to a flowchart. FIG. 6 shows the injector 11 according to the present embodiment.
FIG. 4 is a flowchart showing “various control routines” for controlling various types of fuel injection and performing various types of control such as fuel injection.
It is executed in the main routine. However, in the present embodiment, since the control content when the throttle valve 23 is abnormal is characteristic, the control will be mainly described.

When the processing shifts to this routine, the ECU
First, in step 101, the various sensors 2
Various signals such as engine speed NE, accelerator opening ACCP, cooling water temperature THW, intake pressure PiM, etc. are read from 5 to 29, 61, 62 and the like, and various flags such as throttle fail flag XFTRT are read from the RAM 32.

Next, at step 102, it is judged if the throttle fail flag XFTRT is "1". Here, throttle fail flag XFTR
T is a flag for determining abnormality of the throttle valve 23, and is determined in a separate routine. That is, in the normal state (when the throttle valve 23 is normal), the throttle fail flag XFTRT is set to "0". Then, when there is a deviation of a predetermined amount or more between the throttle opening TA actually detected by the throttle sensor 25 and the required opening, or when an electrical circuit abnormality occurs, the throttle valve 23 is opened. It is determined that an abnormality has occurred, and in such a case, the throttle fail flag X
The FTRT is set to "1".

If it is determined in step 102 that the throttle fail flag XFTRT is not "1", it is determined that the throttle valve 23 has no abnormality, and the process proceeds to step 103.

In step 103, the basic injection amount QINJ is calculated by referring to a map (not shown) based on the engine speed NE and the accelerator opening ACCP which have been read this time. Further, in the subsequent step 104, the final injection amount Qf is obtained by adding the idle injection amount Qidle, which is the minimum required to secure the predetermined idle speed, to the basic injection amount QINJ calculated this time.
Set as

Then, in step 105, the target injection timing AINJ, the target ignition timing SA, the target EGR opening EGRP, and the target swirl control are opened based on the engine speed NE read this time and the final injection amount Qf calculated this time. Degree SCVP, target throttle opening TRTP
Is calculated. In addition, various actuators (fuel injection valve 11, step motor 1
9, 22, the igniter 12, the EGR valve 53, etc. are controlled, and the subsequent processing is once ended.

On the other hand, if it is determined in step 102 that the throttle fail flag XFTRT is "1", it is determined that an abnormality has occurred in the throttle valve 23, and the process proceeds to step 106.

In step 106, it is determined whether or not the cooling water temperature THW read this time is higher than a predetermined value (for example, "80 ° C."). When the cooling water temperature THW is higher than “80 ° C.”, for example,
Assuming that the warm-up has already been completed, the process proceeds to step 107.

In step 107, it is determined whether or not the accelerator opening ACCP read this time is equal to or smaller than a predetermined opening α. Here, as described above, when the accelerator opening degree ACCP is smaller than the predetermined opening degree α, the valve body 23a is in contact with the stopper 42, and the throttle opening degree is maintained at the position Q ₀ near the fully closed position. It will be. Then, in such a case, in step 108, the stoichiometric control flag XI is set in order to perform the stratified charge combustion.
Set NJDJ to "0".

Further, in the following step 109, in order to perform stratified charge combustion, the idle injection amount Qidle, which is the minimum required to secure the above idle speed, is added to the value obtained by multiplying the accelerator opening ACCP by the coefficient k. The value is set as the final injection amount Qf.

In step 110, the target injection timing AINJ, the target ignition timing SA, the target EGR opening EGRP, and the target swirl control are opened based on the engine speed NE read this time and the final injection amount Qf calculated this time. Degree SCVP is calculated. Furthermore, various actuators (fuel injection valve 1
1. Step motor 19 (for swirl control valve 17), igniter 12, EGR valve 53, etc.
Control, and the subsequent processing is ended once.

When the cooling water temperature THW is, for example, "80 ° C." or less in step 106, it is determined that the warm-up is not completed yet, and the process proceeds to step 111. Further, when the accelerator opening ACCP is larger than the predetermined opening α in step 107, the process also goes to step 111. Here, the accelerator opening ACCP
Is greater than the predetermined opening α, as described above, the valve body 23a becomes
The key 46 is opened until it abuts the third wall 47. That is, as the accelerator opening ACCP increases, the throttle opening also increases and the intake air amount increases. In such a case, the stoichiometric control flag XINJDJ is set to "1" in step 111 in order to execute the stoichiometric air-fuel ratio operation (stoichiometric operation).

In the following step 112, the final injection amount Qf is calculated and set by referring to a map (not shown) based on the engine speed NE and the intake pressure PiM in order to perform the operation at the stoichiometric air-fuel ratio. To do.

Then, in step 113, the target injection timing AINJ, the target ignition timing SA, the target EGR opening EGRP, and the target swirl control are opened based on the engine speed NE read this time and the final injection amount Qf calculated this time. Degree SCVP is calculated. Furthermore, various actuators (fuel injection valve 1
1. Step motor 19 (for swirl control valve 17), igniter 12, EGR valve 53, etc.
Control, and the subsequent processing is ended once.

As described above, in the above "various control routines", when there is no abnormality in the throttle valve 23, the final injection amount Qf is calculated based on the engine speed NE and the accelerator opening ACCP, and Various controls such as fuel injection timing control, ignition timing control, EGR control, swirl control and throttle control are executed based on the final injection amount Qf and the like. Further, when the throttle valve 23 is abnormal, after the completion of warming up and when the accelerator opening ACCP is equal to or less than the predetermined opening α, the operation in the stratified combustion is executed. Further, when an abnormality occurs in the throttle valve 23, it is cold, or the accelerator opening AC
When CP is larger than the predetermined opening α, the operation at the stoichiometric air-fuel ratio is executed.

Next, the effect peculiar to this embodiment will be described. (A) As described above, according to the present embodiment, when it is premised that the warm-up is completed, when the abnormality of the throttle valve 23 is detected, the accelerator opening ACCP is equal to or less than the predetermined opening α. The operation in the stratified charge combustion is carried out. Moreover, at this time, as shown in FIG. 9, when the accelerator opening ACCP is equal to or smaller than the predetermined opening α, the throttle opening is constant in structure and the intake air amount is also constant. In order to increase the torque, the fuel amount is increased by stratified combustion (solid line in FIG. 9). Therefore, compared with the operation at the stoichiometric air-fuel ratio, the torque is not significantly increased, and the torque can be smoothly increased according to the increase of the accelerator opening ACCP.

(B) Further, when the accelerator opening ACCP is larger than the predetermined opening α, the operation at the stoichiometric air-fuel ratio is executed. Moreover, at this time, as shown by the solid line in FIG. 9, the throttle opening is structurally different from the accelerator opening ACC.
Since the final injection amount Qf is set based on the engine speed NE and the intake pressure PiM at this time, the intake air amount and the fuel injection amount are sufficient. The required output torque can be secured. As a result, smooth evacuation traveling can be performed.

(C) From the above (a) and (b), according to the present embodiment, even if an abnormality occurs in the throttle valve 23, the driver's request and the throttle accelerator opening ACCP are required.
It is possible to perform output control according to.

(D) Further, in the present embodiment, not only the final injection amount Qf at the time of failure but also the target values of the injection timing at the time of failure, the ignition timing, the EGR opening degree, the opening degree of the swirl control valve 17, etc. are set. Calculated separately, based on these target values, injection timing control, ignition timing control, EGR control,
Various controls such as swirl control are executed additionally. Therefore, even when the throttle valve 23 has an abnormality, it is possible to perform control suitable for the driver's request, such as retreat traveling, in various types of control.

(C) In addition, in the present embodiment, it is assumed that the operation is performed at the stoichiometric air-fuel ratio during cold. Therefore, when the accelerator opening ACCP is equal to or less than the predetermined opening α, it is possible to obtain a larger fuel injection amount and a higher output torque as compared with the operation in the stratified combustion (two-dot chain line in FIG. 9). It is possible to execute the control that is more suitable for the driving state.

The present invention is not limited to the above embodiment, but may be configured as follows, for example. (1) In the above embodiment, in step 113,
Target injection timing AINJ and target ignition timing S at the time of failure
When calculating A, the target EGR opening degree EGRP, and the target swirl control opening degree SCVP, the engine speed NE
Although the final injection amount Qf calculated this time is taken into consideration, the intake pressure PiM may be taken into consideration instead of the final injection amount Qf.

(2) In the above embodiment, the intake pressure PiM is detected as the required load (Dj
Type), an air flow meter or the like to detect the amount of intake air, and the load may be considered based on the detected value (Lj type).

(3) In the above embodiment, the case where only one throttle valve 23 is provided is embodied, but it is also possible to embody the type having two valves in series or in parallel.

(4) In the above embodiment, the so-called electronically controlled throttle valve 23 is adopted.
A so-called mechanical type linked to the accelerator pedal 24 may be adopted. However, in this case, in addition to the configuration of the above-described embodiment, it is necessary to form a so-called dual system that is separately connected to the accelerator pedal 24.

(5) In the above embodiment, the present invention is embodied in the in-cylinder injection type engine 1. However, any type of internal combustion engine of so-called stratified charge combustion or weakly stratified charge combustion can be used. It may be embodied in a thing. For example, a type that injects toward the back side of the cap portion of the intake valves 6a and 6b of the intake ports 7a and 7b is also included. Although a fuel injection valve is provided on the intake valves 6a and 6b side, a type in which fuel is injected directly into the cylinder bore (combustion chamber 5) is also included.

(6) Further, in the above-mentioned embodiment, the structure has the intake port on the helical side so that the so-called swirl can be generated, but it is not always necessary to generate the swirl. Therefore, for example, the swirl control valve 17, the step motor 19, and the like in the above embodiment can be omitted. Similarly, EG
The R device 53 may be omitted.

(7) Although not described in the above embodiment, in the case where the various target values when the throttle valve 23 is abnormal can be shared with those in the normal state, the target values may be shared. It doesn't matter. Further, particularly in step 113, the target injection timing AIN is simply
It does not matter even if J is set to a constant value and the target EGR opening degree EGRP is set to "0".

(8) In the above embodiment, the operation is switched between stratified combustion operation and stoichiometric air-fuel ratio operation at the predetermined opening α.
Alternatively, hysteresis may be set. In such a case, it is possible to make the fluctuations in the fuel injection amount and the torque smoother. Further, the specific numerical value of the predetermined opening degree α is not limited to that in the above embodiment.

The technical idea which is not described in each claim of the claims and can be grasped from the above-mentioned embodiment will be described below together with its effect. (A) In the fuel injection control device for an internal combustion engine according to any one of claims 1 to 5, when the internal combustion engine is cold, operation is performed at a stoichiometric air-fuel ratio.

With the above structure, it is possible to further secure an operating condition more suitable for the internal combustion engine.

[0068]

As described in detail above, according to the fuel injection control apparatus for an internal combustion engine of the present invention, even if the throttle valve is abnormal, combustion becomes impossible and a sudden increase in output is caused. This has an excellent effect that it is possible to smoothly perform the evacuation traveling in response to the driver's request without making a trip.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram illustrating a basic conceptual configuration of the present invention.

FIG. 2 is a schematic configuration diagram showing a fuel injection control device for an engine.

FIG. 3 is an enlarged cross-sectional view showing a cylinder portion, a port portion and the like of the engine.

FIG. 4 is a schematic diagram for explaining a configuration of a throttle valve.

FIG. 5 is a graph for explaining the opening characteristic of the throttle valve with respect to the accelerator opening when the throttle valve is normal and when it is abnormal.

[Fig. 6] "Various control routines" executed by the ECU
It is a flowchart which shows.

FIG. 7 is a schematic diagram for explaining an operation when the throttle valve is abnormal.

FIG. 8 is a schematic diagram for explaining the operation when the throttle valve is abnormal.

FIG. 9 is a graph showing a relationship between an output torque, a fuel injection amount, an intake air amount, and a throttle opening with respect to an accelerator opening.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as internal combustion engine, 1a ... Cylinder, 11 ... Fuel injection valve as fuel injection means, 15a ... 1st intake passage which comprises an intake passage, 15b ... 2nd intake passage which constitutes an intake passage, 16 ... Intake Surge tanks that make up the passage, 20 ...
Intake duct constituting the intake passage, 23 ... Throttle valve,
25 ... A throttle sensor that constitutes an operating state detecting means,
26 ... Accelerator sensor which constitutes an operating state detecting means, 2
7 ... Top dead center sensor constituting operating state detecting means, 28 ...
Crank angle sensor, which constitutes an operating state detecting means, 29 ...
A swirl control valve sensor constituting the operating state detecting means, 30 ... An ECU constituting the fuel injection control means, the abnormality detecting means and the injection form changing means, 61 ... An intake pressure sensor constituting the operating state detecting means, 62 ... Operating state detection A water temperature sensor that constitutes a means.

Claims (5)

[Claims] 1. A fuel injection means for injecting fuel into a cylinder of an internal combustion engine for performing stratified combustion and homogeneous combustion; and an intake air amount provided in the intake passage of the internal combustion engine and supplied into the cylinder. A throttle valve for adjusting the operating condition, operating condition detecting means for detecting a required operating condition of the internal combustion engine, and injection from the fuel injecting means into the cylinder based on a detection result of the operating condition detecting means. In a fuel injection control device for an internal combustion engine, comprising: a fuel injection control unit that controls fuel injection, the fuel injection control unit includes an abnormality detection unit that detects an abnormality of the throttle valve; When a valve abnormality is detected, the injection mode of the fuel injected from the fuel injection means is changed according to the accelerator opening detected by the operating state detection means. A fuel injection control device for an internal combustion engine, comprising: an injection mode changing means. 2. The injection mode changing means controls the fuel injection means to perform stratified charge combustion when the accelerator opening is smaller than a predetermined opening, and when the accelerator opening is larger than the predetermined opening. The fuel injection control device for an internal combustion engine according to claim 1, wherein the fuel injection means is controlled to perform combustion at a stoichiometric air-fuel ratio. 3. The throttle valve is driven by an actuator, and the actuator is
The throttle opening control means controls the throttle opening based on the detection result of the operating state detecting means, and when the accelerator opening is smaller than the predetermined opening when the throttle valve itself is abnormal, the throttle opening is smaller than the predetermined opening. Is held at a position near the fully closed position, and when the accelerator opening is larger than the predetermined opening, the throttle opening is adjusted to increase with the increase of the accelerator opening. The fuel injection control device for an internal combustion engine according to claim 2. 4. The fuel injection control device for an internal combustion engine according to claim 3, wherein the position near the fully closed position is an opening degree sufficient for idling the internal combustion engine. 5. The fuel injection control for an internal combustion engine according to claim 3, wherein the position near the fully closed position is an opening degree sufficient to secure a negative pressure for braking. apparatus.