JPH08200116A - Cylinder fuel injection-type internal combustion engine - Google Patents

Abstract

PURPOSE: To prevent inferior combustion of an engine by performing control wherein air-fuel mixture in the homogeneous state is formed by a second control means, instead of control wherein air-fuel mixture in the laminated state in a cylinder of the engine is generated by a first control means, when abnormality of an intake air swirl control means is detected. CONSTITUTION: Fuel are directly injected into cylinders 1a of an engine by first combustion injection valves 11. The magnitude of the swirl to be generated in a combustion chamber by the intake air flow to flow into the combustion chambers in the cylinders is controlled by an intake air swirl control means 17 according to the operating state of the engine. The engine is controlled by the first control means so that the stratified air-fuel mixture may be formed into the cylinders according to the operating state of the engine. An abnormality detecting means 29 for detecting abnormalities of the intake air swirl control means 17 is provided on the engine. A second control means is provided for controlling the engine, so that the homogeneous air-fuel mixture may be formed into the cylinders according to the operating state of the engine, instead of the first control means, when the abnormalities of the intake air swirl flow control means 17 are detected by this abnormality detecting means 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder injection type internal combustion engine, and more particularly, to a means for detecting an abnormality of an intake swirling flow control means for generating a swirl flow, which produces a mixture in a cylinder of the engine. The present invention relates to a cylinder injection internal combustion engine in which the intake swirl flow control means is in a stratified state when the intake swirl flow control means is normal and is in a homogeneous state when the intake swirl flow control means is abnormal.

[0002]

2. Description of the Related Art An in-cylinder injection type internal combustion engine disclosed in Japanese Patent Laid-Open No. 5-79337 has a fuel injection valve for directly injecting fuel into a combustion chamber, and the injection timing of the fuel injection valve is set when the engine is operated under a low load. At the end of the compression stroke, in medium- and high-load operation, in a cylinder injection internal combustion engine that is set to the intake stroke, the strength of the swirl flow generated in the combustion chamber by the intake air flow flowing into the combustion chamber is adjusted according to the engine load. It is equipped with a swirl flow control device that controls the combustion flame by making the strength of the swirl flow when the engine load is medium load stronger than that when the engine load is low and high. It is characterized by increasing the propagation speed of.

[0003]

In such a conventional cylinder injection type internal combustion engine, when an abnormality occurs in the intake control valve which is the actuator of the swirling flow control device, combustion failure occurs and drivability deteriorates. There's a problem.

Therefore, an object of the present invention is to solve the above-mentioned problems, that is, to provide an in-cylinder injection type internal combustion engine that can be operated with good drivability without causing combustion failure when an abnormality occurs in the intake control valve. And

[0005]

An in-cylinder injection type internal combustion engine according to the present invention which achieves the above-mentioned object, flows into a first fuel injection valve for directly injecting fuel into a cylinder of the engine and a combustion chamber in the cylinder. An intake swirl flow control means for controlling the strength of the swirl flow generated in the combustion chamber by the intake air flow according to the operating state of the engine, and an engine for generating a stratified mixture in the cylinder according to the operating state of the engine. In the in-cylinder injection internal combustion engine including the first control means for controlling the above, the abnormality detection means for detecting an abnormality in the intake swirl flow control means, and the abnormality detection means detects an abnormality in the intake swirl flow control means. At this time, instead of the first control means, a second control means for controlling the engine so as to generate a homogeneous mixture in the cylinder in accordance with the operating state of the engine,
It is characterized by having.

In the cylinder injection type internal combustion engine of the present invention, the injection timing of the first fuel injection valve is always set to the intake stroke by the second control means regardless of the operating state of the engine.

The cylinder injection type internal combustion engine of the present invention further comprises a second fuel injection valve for injecting fuel toward an intake port of the engine at an injection timing corresponding to an operating state of the engine to generate a homogeneous mixture, The second control means sets the injection timing of the second fuel injection valve to the intake stroke regardless of the operating state of the engine.

[0008]

In the cylinder injection type internal combustion engine of the present invention, when the abnormality detecting means detects the abnormality of the intake swirling flow control means, the first control means generates the air-fuel mixture in the cylinder of the engine. Instead of the control, the second control means controls so as to generate the air-fuel mixture in a homogeneous state, so that the engine does not become defective in combustion even when the intake swirling flow control means is abnormal.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram of a cylinder injection type internal combustion engine. As shown in this figure, the engine body 1 is provided with four cylinders 1a, and the combustion chamber structure of each cylinder 1a is shown in FIGS. 2 to 5, reference numeral 2
Is a cylinder block, 3 is a piston that reciprocates in the cylinder block 2, 4 is a cylinder head fixed on the cylinder block 2, 5 is a combustion chamber formed between the piston 3 and the cylinder head 4, and 6a is the first An intake valve, 6b is a second intake valve, 7a is a first intake port, 7b is a second intake port, 8 is a pair of exhaust valves, and 9 is a pair of exhaust ports. As shown in FIG. 2, the first intake port 7a is a helical intake port, and the second intake port 7b is
Consists of a straight port that extends almost straight. Further, as shown in FIG. 2, a spark plug 10 is arranged at the center of the inner wall surface of the cylinder head 4, and the first intake valve 6a
A fuel injection valve 11 is arranged near the inner wall surface of the cylinder head 4 near the second intake valve 6b. 3 and 4
The fuel injection valve 1 is installed on the top surface of the piston 3 as shown in FIG.
1, a shallow dish portion 12 having a substantially circular contour shape extending from below 1 to below the ignition plug 10 is formed.
A basin portion 13 having a substantially hemispherical shape is formed in the central portion of the. In addition, the shallow pan 12 and the deep pan 13 below the spark plug 10
A concave portion 14 having a substantially spherical shape is formed at the connecting portion with.

As shown in FIG. 1, the first intake port 7a and the second intake port 7b of each cylinder 1a pass through a first intake passage 15a and a second intake passage 15b formed in each intake branch pipe 15, respectively. And a swirl control valve (swirl control valve) 17 is arranged in each second intake passage 15b. These intake swirl control valves 17 are common to the shaft 1
It is connected via 8 to an actuator 19 composed of, for example, a step motor. This step motor is controlled based on the output signal of the electronic control unit 30. The actuator 19 may be one that is controlled according to the negative pressure of the intake port of the engine. The rotation angle of the shaft 18 is detected by the intake swirl flow control valve opening sensor 29, and the opening of the intake swirl flow control valve 17 is measured thereby. The output of the intake swirling flow control valve opening sensor 29 is A
It is connected to the input port 35 via the / D converter 39.
The surge tank 16 is connected to an air cleaner 21 via an intake duct 20. Inside the intake duct 20, a throttle valve 23 driven by a step motor 22 is arranged. The throttle valve 23 is closed to some extent only when the engine load is extremely low, and is kept fully open when the engine load is slightly increased. On the other hand, the exhaust port 9 of each cylinder 1a is connected to the exhaust manifold 24.

The electronic control unit 30 comprises a digital computer, and a RAM (random access memory) 32 and a ROM connected to each other via a bidirectional bus 31.
A (read only memory) 33, a CPU (central processing unit) 34 including a microprocessor, an input port 35 and an output port 36 are provided. A load sensor 26 that generates an output voltage proportional to the depression amount of the accelerator pedal 25 is connected to the accelerator pedal 25, and the output voltage of the load sensor 26 is input to the input port 35 via the AD converter 37. The top dead center sensor 27 generates an output pulse, for example, when the first cylinder 1a reaches the intake top dead center, and this output pulse is input to the input port 35. The crank angle sensor 28 generates an output pulse each time the crankshaft rotates 30 °, for example, and this output pulse is input to the input port 35.
Is input to The CPU 34 calculates the current crank angle from the output pulse of the top dead center sensor 27 and the output pulse of the crank angle sensor 28, and calculates the engine speed from the output pulse of the crank angle sensor 28. On the other hand, output port 3
6 is connected to each fuel injection valve 11 and each step motor 19, 22 via the corresponding drive circuit 38.

The embodiment according to the present invention is shown in FIGS.
In F₁, F₂And F₃Fuel injection as shown in
Fuel is injected from the valve 11 in three directions. Figure 6
Is the fuel injection amount and fuel injection timing from this fuel injection valve 11.
Is shown. In FIG. 6, L is an accelerator pedal
The amount of depression of the rule 25 is shown. As you can see from Figure 6
The amount L of depression of the accelerator pedal 25 is L₁Less than
During low engine load operation, injection quantity Q at the end of compression stroke₂Just burn
Charge injection is performed. On the other hand, depressing the accelerator pedal 25
The amount L is L₁And L₂During engine load operation during
Injection amount Q ₁Fuel injection is performed only at the end of the compression stroke
Injection quantity Q₂Only fuel is injected. That is, negative in the organization
During load operation, the fuel is divided into two parts, the intake stroke and the end of the compression stroke.
Charge injection is performed. Also, depressing the accelerator pedal 25
The amount L is L₂Intake stroke during engine high load operation
Injection amount Q₁Only fuel is injected. In addition, in FIG.
Where θS1 and θE1 are the fuel that is performed during the intake stroke
Injection Q₁The injection start timing and injection completion timing of
And θS2 and θE2 are performed at the end of the compression stroke.
Fuel injection Q₂The injection start timing and injection completion timing of
Shows.

By the way, in the embodiment according to the present invention, as shown in FIG. 2, the injected fuels F ₁ , F ₂ are injected from the fuel injection valve 11.
Flies below the first intake valve 6a, and the injected fuel F ₃ becomes the second
The fuel is injected so as to fly below the intake valve 6b, and during the first injection during the intake stroke injection during the engine medium load operation, that is, during the intake stroke injection, and during the intake stroke injection during the engine high load operation. Injection fuel F ₁ , F
₂ collides with the back surface of the first intake valve 6a at the bulge portion, and the injected fuel F
₃ collides with the back surface of the second air intake valve 6b. Next, this will be described with reference to FIGS. 7 and 8.

FIG. 7 shows the valve lift X of the first intake valve 6a and the second intake valve 6b and the valve lift Y of the exhaust valve 8. As can be seen from FIG. 7, the first intake valve 6a and the second intake valve 6b
The valve lift X of is the largest in the central part of the intake stroke. FIG. 8 shows the relationship between the first intake valve 6A and the injected fuel F ₁ . As shown in FIG. 8, the injected fuel F ₁ is injected slightly downward from the horizontal plane. Although not shown in FIG. 8, the injected fuels F ₂ and F ₃ are also injected slightly downward from the horizontal plane like the fuel injection F ₁ . As can be seen from FIG.
(A), when the lift amount of the first intake valve 6a is small, the injected fuel F ₁ does not collide with the first intake valve 6a, and as shown in (B) of FIG. The relative position of the first intake valve 6a and the fuel injection valve 11 and the fuel injection direction from the fuel injection valve 11 are determined so that the injected fuel F ₁ collides with the back surface of the bulkhead of the first intake valve 6a when the amount increases. ing. In Z of FIG. 7, the injected fuel F ₁ is the first intake valve 6
The crank angle area | region which collides with the back surface of the umbrella part of a is shown. Although not shown in FIG. 8, the injected fuel F ₂ also collides with the rear surface of the bulge portion of the first intake valve 6a in the crank angle region Z, and the injected fuel F ₃ also in the crank angle region Z in the second intake valve 6b. It collides with the back of the umbrella.

If the fuel is injected from the fuel injection valve 11 in the crank angle region Z shown in FIG. 7 as described above, the injected fuel F ₁ is the back surface of the first intake valve 6a as shown in FIG. 8B. Clash with. At this time, if the flow velocity of the injected fuel F ₁ is slow, the injected fuel F ₁ collides with the back surface of the bulge portion of the first intake valve 6a and then burns on the side opposite to the fuel injection valve 11 along the back surface of the bulge portion of the first intake valve 6a. Toward the periphery of chamber 5 but injected fuel F
_When the flow velocity of ₁ is high, the injected fuel F ₁ collides with the back surface of the bulkhead portion of the intake valve 6a and then is reflected and travels into the first intake port 7a, as shown in FIG. 8B. Similarly injected fuel F injected fuel F ₂ if the flow velocity is fast in ₂ toward the first intake port 7a is reflected after having collided with the rear bevel portion of the first intake valve 6a, the injection if Hayakere the flow velocity of the injected fuel F ₃ Fuel F ₃ is second
After colliding with the rear surface of the bulge portion of the intake valve 6b, it is reflected and travels into the second intake port 7b. In the embodiment according to the present invention, after each of the injected fuels F ₁ , F ₂ , F ₃ is reflected on the back surface of the corresponding bulkhead of the intake valves 6a, 6b, the corresponding intake port 7
a, 7b so that the injected fuels F ₁ , F ₂ , F ₃
The flow velocity of is fixed. The flow velocity is mainly determined by the fuel injection pressure, and in the embodiment of the present invention, the fuel injection pressure is set to 70 Kg / cm ² or more.

FIG. 9 is a flow chart of the intake swirling flow control valve abnormality detection routine of the present invention. In the figure, the numbers following S indicate step numbers. This routine is executed every few ms. First, in step S1, the presence or absence of fail detection is determined by the fail-safe flag XFSCVP.
That is, when XFSCVP = 0, it is determined that the fail detection has not been performed before, and the process proceeds to step S2, where XFSC
When VP = 1, it is determined that the fail detection has been performed before, and the process proceeds to step S11. Fail Safe Flag XF
The SCVP is set from 0 to 1 when it is determined that the intake swirl flow control valve (swirl control valve) is abnormal. The fail determination for determining whether or not there is an abnormality in the intake swirl flow control valve is executed as follows by comparing the current opening data SCVP of the intake swirl flow control valve with the command opening data SCVR. The command opening data SCVR of the intake swirling flow control valve is data determined according to the load of the engine and the engine speed, and is R in advance.
Stored in OM. The command opening degree data SCVR of the intake swirling flow control valve in this embodiment is set to data that the valve is slightly opened during low load operation, fully closed during medium load operation, and fully opened during high load operation.

In step S2, the current opening degree data SCVP of the intake swirl flow control valve and the command opening degree data SCVR are compared to determine whether or not the absolute value of the difference is equal to or greater than a predetermined value α.
If SCVP-SCVR | ≧ α, go to step S3 | S
When CVP-SCVR | <α, the process proceeds to step S4.
This current opening data SCVP is the command opening data SCVR.
If the setting is changed and does not change after the lapse of a predetermined time, it is considered as an abnormality due to a disconnection of the opening sensor of the intake swirl flow control valve, and this routine is not executed and a flag indicating an output abnormality of the opening sensor is set and displayed. You may show with a container. In step S3, the count value of the counter CFSCVP is a predetermined value a.
If it is YES, the process proceeds to step S5, and if NO, the process proceeds to step S6.
The counter CFSCVP is incremented by 1 every few ms and is reset to 0 every time in step S4 of this routine. After the determination result of step S2 is YES, the counter CFSCVP is not reset to 0 and counts up every few ms. Until the time for the counter CFSCVP to count up to the predetermined value a has elapsed, the determination result in step S3 becomes NO, the process proceeds to step S6, the counter CRSCVP is reset to 0, and this routine is ended. After that, this routine proceeds to steps S1 and S
The execution of steps 2, S3 and S6 is repeated, and after a time corresponding to a has elapsed, the process proceeds from step S3 to S5.

In step S5, it is determined that the intake swirl flow control valve is abnormal, and the fail-safe flag XFSCVP is set to 1
And set to step S7. In step S7, the current opening degree data SCVP of the intake swirling flow control valve is stored in the backup memory. The opening degree data of the intake swirling flow control valve stored in this backup memory is called SCVPB.
Also, the counter CRSCVP is several ms like CFSCVP.
Each time it is incremented by 1, it is reset to 0 every time in step S6 of this routine.

Next, when the routine is started again after the fail determination is made in step S5, step S1
Since the fail-safe flag XFSCVP has been set to 1, the process proceeds to step S11. In step S11, the opening degree data SCVPB of the intake swirling flow control valve stored in the backup memory is compared with the command opening degree data SCVR, and it is determined whether or not the absolute value of the difference is a predetermined value β (α <β) or more. If | SCVPB-SCVR | ≧ β, the process proceeds to step S12. If | SCVPB-SCVR | <β, the process proceeds to step S4.

In step S12, as in step S2, the present opening degree data SCVP and the command opening degree data SC of the intake swirling flow control valve in the current processing cycle of this routine.
VR is again compared to determine whether the absolute value of the difference is smaller than a predetermined value α, and if | SCVP-SCVR | <α, proceed to step S13, and if | SCVP-SCVR | ≧ α, proceed to step S13. Proceed to S4. In step S4, the counter C
FSCVP is reset to 0 and the process proceeds to step S6. In step S6, the counter CRSCVP is reset to 0 and this routine ends.

In step S13, the counter CRSCVP
It is determined whether or not the value of is counted up to the predetermined value b, and if the result of the determination is YES, to step S15,
If NO, this routine ends. This counter C
The RSCVP is reset to 0 each time in step S6 of this routine until it is determined YES in step S3. The counter CRSCVP is incremented by 1 every few ms after the determination in step S3 is YES.
However, when the determination result of step S12 is NO, the counter CRSCVP is reset to 0 in step S6 via step S4.

In step S13, the counter CRSCVP
It is determined whether or not the count value of has reached the predetermined value b. If the determination result is YES, the process proceeds to step S15, and if NO, the routine ends. When the result of the determination in step S12 is YES after the determination in step S3 is YES, the counter CRSCVP is not reset to 0 and continues counting up every few ms. Counter C
Until the time for the RSCVP to count up to the predetermined number b has elapsed, the determination result of step S13 becomes NO, and this routine ends, after which this routine repeats execution of steps S1, S11, S12, S13, and YES at step S3. In step S13 after the time corresponding to b has elapsed after the determination is made, the process proceeds to step S15. In step S15, it is determined that the intake swirling flow control valve is normal, the fail-safe flag XFSCVP is reset to 0, and this routine ends.

FIG. 10 is a main flowchart of the fail-safe control routine of the present invention. In the figure, the numbers following S indicate step numbers. This routine is 180 ° CA (crank angle) for a 4-cylinder engine and 1 for a 6-cylinder engine.
It is a crank angle interrupt processing routine that is interrupted every 20 ° CA to calculate the ignition timing and the fuel injection timing of each cylinder.
First, in step S1, the engine speed NE and the load sensor 2
The accelerator opening degree θA corresponding to the load detected in 6 is read. In step S2, the fuel injection amount Q with respect to the rotational speed NE and the accelerator opening degree θA read in step S1.
Read INJ from Map 1 (FIG. 11). This map 1 is experimentally obtained and stored in the ROM in advance.

In step S3, the fail-safe flag X determined by the above-described intake swirl flow control valve abnormality detection routine.
Determine if FSCVP is set to 1 and X
When FSCVP is 1, the process proceeds to step S4 and XFSC
When VP is 0, the process proceeds to step S11. Step S1
In No. 1, the intake swirl flow control valve is determined to be normal, so the control routine for normal time described below is executed and this routine is ended.

In step S4, the injection pattern command data XINJP of the engine is set to 2. In the present embodiment, this injection pattern command data is set to 0, 1 or 2 depending on the engine load and engine speed. Command data 0 executes a compression stroke injection at low load, command data 1 executes two injections that perform both intake stroke injection and compression stroke injection at a medium load, and command data 2 executes intake stroke injection at a high load. To order. In this step S4, the injection pattern command data XINJP is set to 2, and the engine load is low, medium,
Command to perform intake stroke injection in either case of high.

In steps S5 to S8, the throttle valve opening TRT, the EGR valve opening EGR, the ignition timing SA, and the injection timing AINJ for producing a homogeneous mixture in the cylinder by the intake stroke injection by the ignition timing are set. The engine speed NE and the accelerator opening degree θA read in S1 and the fuel injection amount QINJ calculated in step S2
It is calculated based on each. That is, in step S5, the throttle valve opening TRT is calculated from the map 2 (FIG. 12). The throttle valve opening TRT for generating a homogeneous air-fuel mixture in the cylinder by the ignition stroke injection by the ignition timing is the same fuel injection amount QINJ during the compression stroke injection.
As compared with the case where the injection is performed to generate the stratified mixture, the mixture becomes richer and the air-fuel ratio becomes smaller, so that it is throttled. Step S
6 maps the EGR rate of the exhaust gas recirculation system EGR 3
(FIG. 13). The EGR amount required to suppress the generation of NOX is set to a small amount as compared with the case where the compression stroke injection is performed to generate the stratified mixture. Note that, as shown in FIG. 13, the EGR rate is set to decrease as the fuel injection amount QINJ increases, that is, the engine load increases, and decreases as the engine speed NE increases. To be done. In step S7, the ignition timing SA is calculated from the map 4 (FIG. 14). The ignition timing SA is set to the advanced side from the compression top dead center so as to obtain the maximum combustion torque, but is set to the advanced side slightly compared with the case where the compression stroke injection is performed to generate the stratified mixture. In step S8, the injection timing AINJ of the intake stroke of the fuel injection valve is set to map 5 (see FIG.
Calculated from 5). The above map is experimentally obtained and R
Stored in OM.

In step S9, the map 6 in which the ignition timing correction coefficient K _SA and the injection timing correction coefficient K _AINJ for the output of the opening sensor of the intake swirling flow control valve are stored in the ROM in advance.
(FIG. 16). These coefficients are set to 1 when the swirl flow when the intake swirl flow control valve is fully closed is the strongest, and the swirl flow weakens as the intake swirl flow control valve opens. The ignition timing and the injection timing are corrected so that they are on the advance side of the ignition timing and the injection timing when the flow control valve is fully closed. In step S10, step S9
The ignition timing correction coefficient K _SA calculated in step S3 is multiplied by the ignition timing SA when the intake swirl flow control valve is fully closed, and step S
The injection timing correction coefficient K _AINJ calculated in 9 is multiplied by the injection timing AINJ when the intake swirl flow control valve is fully closed to calculate the current ignition timing SA and the injection timing AINJ. In this way, the strength of the swirl flow generated in the cylinder changes according to the opening degree of the intake swirl flow control valve when the intake swirl flow control valve fails, and the swirl flow becomes Since it weakens, if the opening of the intake swirl flow control valve is opened when the intake swirl flow control valve fails, the injection timing AINJ will be corrected to the advance side, and sufficient time for vaporization and diffusion will be obtained, and it will be uniform until ignition. A rich air-fuel mixture can be generated in the cylinder. Further, since the swirling flow becomes weaker as the opening degree of the intake swirling flow control valve is increased, the ignition timing SA is advanced toward the advance side as the opening degree of the intake swirling flow control valve is increased when the intake swirling flow control valve fails. By igniting the engine, the combustion torque of the engine can be maximized.

If there is no intake swirl flow control valve opening sensor for detecting the opening of the intake swirl flow control valve, the throttle opening TRT is set to the accelerator pedal 2 in steps S5 to S8.
5, the output of the load sensor 26, the EGR valve is fully closed,
The ignition timing SA and the injection timing AINJ are calculated from the map 4 and the map 5 based on the engine speed NE and the fuel injection amount QINJ, respectively, as described above, and steps S9 and S1 are performed.
0 is skipped.

FIG. 17 is a detailed flowchart of the control routine when the intake swirling flow control valve is normal. Since it is determined in step S3 of FIG. 10 that the intake swirl flow control valve is normal, this routine executes control when the intake swirl flow control valve is normal. That is, as described in step S3 of FIG. 10, in step S20, the injection pattern command data XINJP corresponding to the engine load and the engine speed is calculated from the map 7 shown in FIG. As shown in FIG. 18, the injection pattern command data XINJP is used for the compression stroke injection of XINJP = 0 when the engine speed is a predetermined load or lower and XINJP = 1 when the engine speed is a medium load or lower. 2 injections that perform both intake stroke injection and compression stroke injection of
When the engine speed is a high load below a predetermined speed or when the engine speed is above a predetermined speed, the intake stroke injection is set to XINJP = 2. The load state of this engine is obtained from the accelerator opening θA. Next, in step S21, the data of the injection pattern command data XINJP calculated in step S20 is read and XINJP is read.
When = 0, the process proceeds to step S23, when XINJP = 1, the process proceeds to step S33, and when XINJP = 2, the process proceeds to step S43.

Next, based on the engine speed NE obtained in step S1 in FIG. 10 and the fuel injection amount QINJ obtained in step S2, in step S23 the throttle opening TRT is set to a map similar to that shown in FIG. 12 (not shown). No.), and in step S24, E of the exhaust gas recirculation device EGR is calculated.
The opening of the GR valve is calculated from a map (not shown) similar to FIG. 13, and the ignition timing SA is calculated from a map (not shown) similar to FIG. 14 in step S25. Step S26
Then, the fuel injection amount Q ₂ of the compression stroke of the fuel injection valve and the injection timing AINJ _{2 of the} compression stroke (start timing θS2 and end timing θE
2) is calculated from the map shown in FIG. 6, and the process proceeds to step S27.

Steps S33 to S35 are step S
Since it is the same as 23 to S25, the description is omitted. In step S36, the fuel injection amount Q _{2 in} the compression stroke of the fuel injection valve and the injection timing AINJ ₂ (start timing θS2 and end timing θE
2) and the intake stroke fuel injection amount Q ₁ and injection timing AIN
J ₁ (start timing θS1 and end timing θE1) is calculated from the map of FIG. 6, and the process proceeds to step S27.

Steps S43 to S45 are step S
Since it is the same as 23 to S25, the description is omitted. In step S46, the fuel injection amount Q ₁ of the intake stroke of the fuel injection valve and the injection timing AINJ ₁ (start timing θS1 and end timing θE1) of the intake stroke are calculated from the map of FIG. 6, and step S2
Proceed to 7.

In step S27, the target opening degree of the intake swirling flow control valve 17 is calculated according to the depression amount θA of the accelerator pedal 25 stored in the ROM in advance. In this way, the opening degree of the intake swirling flow control valve 17 is controlled by driving the step motor 19 so as to reach the target opening degree calculated by the above-mentioned control routine.

The fuel injection amount QINJ calculated from the map 1 shown in FIG. 11 is the injection pattern command data XI.
In the compression stroke injection of NJP = 0, the fuel injection amount Q in the compression stroke
₂ and is equal to the sum of the fuel injection amount Q _{1 in the} intake stroke and the fuel injection amount Q _{2 in} the compression stroke in the double injection of the injection pattern command data XINJP = 1.
In the intake stroke injection of INJP = 2, it is equal to the fuel injection amount Q ₁ in the intake stroke. This fuel injection amount QINJ is a basic fuel injection amount calculated from the engine speed and load, but the actual fuel injection amount is multiplied by the air-fuel ratio correction coefficient FAF and another correction coefficient α, and the other correction term β is used. It is obtained by addition, that is, it is obtained by calculating QINJ × (FAF + α) + β. Therefore, the fuel injection amount Q ₁ in the intake stroke and the fuel injection amount Q _{2 in the} compression stroke obtained in steps S26, S36 and S46 are corrected by the same crank angle interruption process as the fail-safe control routine based on the above equation. . Air-fuel ratio correction coefficient FAF
Is a coefficient for performing feedback control so that the air-fuel ratio of the engine becomes the target air-fuel ratio in accordance with the output of the air-fuel ratio sensor provided in the exhaust system of the engine, and correcting the fuel injection amount.

The internal combustion engine of the embodiment described above is an engine which is arranged in the intake pipe and does not have the second fuel injection valve for injecting fuel toward the intake port. However, the present invention is not limited to the cylinder shown in FIG. The present invention can be applied to a cylinder injection internal combustion engine in which a second fuel injection valve is provided in the intake pipe in addition to the first fuel injection valve for direct injection. In this internal combustion engine, when the intake swirl flow control valve is normal, the injection timing is switched between the compression stroke and the intake stroke in accordance with the operating state of the engine, and control is performed to generate a stratified mixture in the cylinder by the ignition timing. 1 When the abnormality of the control means and the intake swirl flow control valve is detected, the first fuel injection valve is not used and only the second fuel injection valve is used to obtain a homogeneous mixture regardless of the operating state of the engine. Second to control to generate
And a control means. Further, the second control means may be configured to generate the homogeneous air-fuel mixture regardless of the operating state of the engine by using both the first and second fuel injection valves when the abnormality of the intake swirling flow control valve is detected. .

[0036]

As described above, according to the in-cylinder injection type internal combustion engine of the present invention, an abnormality occurs in the intake swirling flow control means of the first control means for stratifying the air-fuel mixture in the cylinder of the engine. At this time, since the air-fuel mixture in the cylinder is switched to the second control means that makes the air-fuel mixture homogeneous, even if an abnormality occurs in the intake swirling flow control means, the engine does not become defective in combustion and can be operated with good drivability.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a cylinder injection internal combustion engine.

FIG. 2 is a plan sectional view of a cylinder head.

FIG. 3 is a plan view of a piston top surface.

4 is a sectional view taken along line IV-IV in FIG.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a diagram showing a fuel injection amount and a fuel injection timing.

FIG. 7 is a diagram showing lift amounts of an intake valve and an exhaust valve.

8 is a side sectional view taken along the same section as FIG.

FIG. 9 is a flowchart of an intake swirling flow control valve abnormality detection routine of the present invention.

FIG. 10 is a main flowchart of a fail-safe control routine of the present invention.

11 is a diagram showing a map 1. FIG.

FIG. 12 is a diagram showing a map 2;

FIG. 13 is a diagram showing map 3;

FIG. 14 is a diagram showing map 4;

FIG. 15 is a diagram showing a map 5;

16 is a diagram showing a map 6. FIG.

FIG. 17 is a detailed flowchart of a control routine when the intake swirling flow control valve is normal.

FIG. 18 is a diagram showing a map 7.

[Explanation of symbols]

6a, 6b ... Intake valve 7a, 7b ... Intake port 8 ... Exhaust valve 10 ... Spark plug 11 ... Fuel injection valve 17 ... Intake swirl control valve (swirl control valve) 19 ... Step motor 29 ... Intake swirl control valve opening Sensor 30 ... Control device

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location F02D 41/34 C 9523-3G F02M 69/00 360 C 69/04 Z

Claims (3)

[Claims] 1. A first fuel injection valve for directly injecting fuel into a cylinder of an engine, and a strength of a swirl flow generated in the combustion chamber by an intake air flow flowing into the combustion chamber in the cylinder. In-cylinder injection provided with intake swirling flow control means for controlling in accordance with the operating state, and first control means for controlling the engine so as to generate a stratified mixture in the cylinder in accordance with the operating state of the engine In an internal combustion engine, an abnormality detecting means for detecting an abnormality of the intake swirling flow control means, and when an abnormality of the intake swirling flow control means is detected by the abnormality detecting means, instead of the first control means, the A cylinder injection type internal combustion engine, comprising: a second control unit that controls the engine so as to generate a homogeneous mixture in the cylinder according to an operating state of the engine. 2. The cylinder injection internal combustion engine according to claim 1, wherein the second control means always sets the injection timing of the first fuel injection valve to the intake stroke regardless of the operating state of the engine. 3. The in-cylinder injection internal combustion engine further comprises a second fuel injection valve for injecting fuel toward an intake port of the engine at an injection timing corresponding to an operating state of the engine to generate a homogeneous mixture, The cylinder injection internal combustion engine according to claim 1, wherein the second control means sets the injection timing of the second fuel injection valve to an intake stroke regardless of the operating state of the engine.