JPH11132077A - Fuel supply control device for stratified combustion internal combustion engine - Google Patents

Abstract

(57) [Summary] [Problem] To prevent an increase in manufacturing cost of a fuel injection device,
Suppress variations in the combustion state. SOLUTION: A combustion state of a combustion chamber CC is determined by an ion detection circuit, and when it is determined that a misfire has occurred, a fuel injection timing TRI is corrected while learning and changing. Thus, even if slight variations occur in the actual fuel injection timing due to product variations in the fuel injection device, it is possible to suppress variations in the combustion state. Therefore, it is possible to suppress a variation in the combustion state while preventing an increase in the manufacturing cost of the fuel injection device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply control device for a stratified combustion internal combustion engine capable of supplying fuel directly to a combustion chamber and capable of stratified combustion. It is.

[0002]

2. Description of the Related Art As described in Japanese Patent Application Laid-Open No. 5-52145, a fuel supply control device for a stratified combustion internal combustion engine injects fuel during a suction stroke to perform premix combustion, and injects fuel during a compression stroke. The fuel injection (supply) timing is controlled so as to switch between the case of stratified combustion and the case of stratified combustion according to the operating state of the engine.

As is well known, stratified combustion refers to combustion in which the overall air-fuel ratio is made extremely thin by using a flammable mixture near the spark plug (see FIG. 13). Premixed combustion (homogeneous combustion) As is well known, this means that the entire combustion chamber is burned as a combustible mixture (see FIG. 14). Therefore, during stratified combustion, so-called (super) lean combustion occurs,
During premixed combustion, normal combustion is performed.

[0004]

When stratified combustion is performed in a stratified combustion internal combustion engine, as shown in FIG. 13, fuel is injected (supplied) at a predetermined time in a compression stroke, and the injected fuel (mixed fuel) is injected. When the fuel reaches the gap of the ignition plug, the ignition plug is energized to perform combustion, so that the fuel injection (supply) timing and the ignition timing (timing for energizing the ignition plug) must be accurately controlled. .

On the other hand, a fuel injection device (fuel supply control device)
Is composed of many parts such as a combustion injection valve and a control circuit for controlling the combustion injection valve, so that a slight variation in the product occurs, and a slight variation in the actual fuel injection timing. Will occur. For this reason, in the case where fuel injection control needs to be performed with extremely high accuracy, as in the case of stratified combustion in a stratified combustion internal combustion engine,
It induces variation in the combustion state.

On the other hand, there is a means for strictly controlling the product variation of the fuel injection device, but this means increases the manufacturing cost of the fuel injection device. Also,
Even if product variations are strictly managed, product variations can be reduced, but product variations cannot be eliminated. Since the number of parts of the spark plug is much smaller than that of the fuel injection device, the product variation can be practically ignored as compared with the product variation of the fuel injection device.

Incidentally, in a so-called port injection type engine in which fuel is injected (supplied) into an intake pipe (intake manifold), ignition is performed after a fuel injection (supply) and after a suction stroke and a compression stroke. Even if the fuel injection (supply) timing deviates slightly from the normal fuel injection (supply) timing (by 1 to 2 degrees in crank angle), the variation in the combustion state due to the deviation of the fuel injection (supply) timing is almost ignored. it can.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to suppress a variation in a combustion state while preventing an increase in manufacturing cost of a fuel injection device.

[0009]

The present invention uses the following technical means to achieve the above object. Claim 1
The invention described in Item 7 is characterized in that when the combustion state determination means determines that the combustion state of the combustion chamber has deteriorated, the fuel supply timing is corrected based on the determination by the combustion state determination means.

Accordingly, even if the actual fuel supply timing slightly varies due to the product variation of the fuel supply device, the fuel supply timing is corrected, so that the variation in the combustion state can be suppressed. Can be. Therefore, it is possible to suppress a variation in the combustion state while preventing an increase in the manufacturing cost of the fuel supply device. by the way,
Since the combustion state is constantly changing due to the aging of the fuel supply device or the like, there is no guarantee that the correction value of the previous fuel supply timing can be effectively applied as it is from this time.

Therefore, the invention according to claim 2 is characterized in that after the fuel supply timing is changed by the supply timing changing means, the combustion state of the combustion chamber is determined by the combustion state determining means. As a result, the fuel supply timing can be corrected to the optimum direction while constantly changing the fuel supply timing, so that the fuel supply timing can be corrected over a long period without being affected by aging of the fuel supply device. Can be suppressed.

When the fuel supply timing is changed by the supply timing changing means, and it is determined that the combustion state of the combustion chamber is deteriorated, the supply timing changing means changes the fuel supply timing. It is desirable to change the fuel supply timing in the opposite direction of the change. According to the invention described in claim 4, the storage means for storing the fuel supply timing corrected by the supply timing correction means even after the stratified combustion internal combustion engine is stopped, and restarting after the stratified combustion internal combustion engine is stopped Sometimes, the fuel supply timing is newly determined based on the fuel supply timing stored by the storage means.

Thus, a new fuel supply timing is determined based on the previous correction of the fuel supply timing.
The fuel supply timing can be efficiently corrected in an appropriate direction in a short time. Preferably, the supply timing correction means corrects the fuel supply timing in consideration of the operation state of the stratified combustion internal combustion engine in addition to the determination by the combustion state determination means, as in the invention according to claim 5.

Further, the combustion state determination means may be configured to make a determination based on an ionic current generated in the combustion chamber, as in the sixth aspect of the invention. In the invention described in claim 7, the supply timing changing means changes the fuel supply timing so that the direction of change of the fuel supply timing changed by the supply timing changing means is different for each combustion chamber. .

Thus, in each combustion chamber, it is possible to prevent the directions of changing the fuel supply timing from overlapping (coinciding with each other), thereby preventing an increase in torque fluctuation and vibration of the stratified combustion internal combustion engine. Therefore, the fuel supply timing can be corrected in an appropriate direction without giving the occupant any discomfort. In addition, the code in parentheses of each of the above means,
It shows the correspondence with specific means described in the embodiment described later.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows a fuel supply control device 100 for a stratified combustion internal combustion engine and four combustion chambers C according to the present embodiment.
FIG. 1 is a schematic diagram showing an outline of a stratified combustion internal combustion engine (hereinafter, referred to as an engine) 200 having a combustion chamber CC.
Is composed of a cylinder 201, a piston 202, and a cylinder head 203.

The cylinder head 203 has an intake valve 204, an exhaust valve 205, a spark plug 206, and a fuel injection valve (fuel supply valve) 101 for injecting (supplying) high-pressure fuel into the combustion chamber CC in a spray state. The fuel in a fuel tank 103 is supplied to a fuel injection valve (hereinafter, abbreviated as an injection valve) 101 by a high-pressure fuel pump 102.

Each intake pipe (intake manifold) communicating with each combustion chamber CC is provided with a throttle valve 103 for adjusting the amount of intake air taken into each combustion chamber CC. An air flow sensor (intake air amount detecting means) 104 for detecting an amount of intake air is provided upstream of the intake air flow 104. Note that the throttle valve 104 is driven by an actuator (not shown) such as a servomotor, and the valve opening of the throttle valve 104 is adjusted by the actuator.

Reference numeral 105 denotes a crank angle sensor (crank angle detecting means) for detecting the crank angle of the crankshaft 207 of the engine, and reference numeral 106 denotes an accelerator pedal (accelerator pedal) operated by an occupant to control the engine speed. Means) a throttle position sensor (throttle opening degree detecting means) for detecting the opening degree of the throttle valve 104 movable in accordance with the operation amount of 108, and 107 an A / F sensor (air-fuel ratio) for detecting the air-fuel ratio of the exhaust gas. Detection means)
It is.

The output signals of the sensors 104 to 107 are input to an electronic control unit (hereinafter, referred to as an ECU) 300.
Based on the signals from 04 to 107, the opening / closing timing (fuel injection timing) of the injection valve 101 and the timing of energizing the ignition plug 206 (ignition timing) are controlled in accordance with a program stored in advance.

As shown in FIG. 2, the ECU 300 includes a well-known microcomputer system including a ROM (read only storage device) 301, a CPU (central processing unit) 302, a RAM (randomly readable storage device) 303, and the like. , And its schematic configuration is described below. Analog signals from the air flow sensor 104 and the A / F sensor 107 are converted into digital values by an A / D converter 305 via an MPX (multiplexer) 304 that selectively outputs the input signals, and a bus that forms a signal path The data is input to the CPU 302 via the line 306.

A signal from the crank angle sensor 105 is input to an input counter 307, and the input counter 307 issues an interrupt signal to the CPU 302 via the bus line 306 according to the crank angle (counter value of the input counter 307). . Throttle position sensor 106
Is input to the input port 308 and then input to the CPU 302 via the bus line 306.

The output counter 309 has a ROM
CPU 302 based on the program stored in CPU 301
The calculated ignition timing, fuel injection amount, injection timing, and the like are input via the bus line 306, and the output counter 309 outputs information such as the ignition timing to the injection drive circuit 310 that drives (opens and closes) the injection valve 101. , And spark plug 2
Drive circuit 31 for energizing ignition coil 206a of No. 06
Output to 1

The signal lines of the ignition coil 206a and the ignition plug 206 are connected to an ion detection circuit (combustion state determination means) 312. The ion detection circuit 312 is connected to the spark gap (ignition plug 2) of each ignition plug 206.
In FIG. 6, an ion current generated between the center electrode and the ground electrode is detected. 313 is an ion detection circuit 31
From each of the ion currents (waveform changes) obtained in step 2, each combustion chamber CC
The combustion quality determination circuit for determining the quality of the combustion state of the combustion chamber CC. The combustion quality determination circuit 313 and the ion detection circuit 312 constitute combustion state determination means for determining the combustion state of the combustion chamber CC. Note that the signal of the combustion quality judgment circuit 313 is output to the input port 308.

Reference numeral 314 denotes a backup memory which is configured to be always supplied with power by the vehicle battery 315 so that its stored contents are retained even after the engine 200 is stopped. As described later, variables (parameters) set during operation of the engine 200 are stored in the engine 20.
It is stored at the same time as the stop of 0.

Next, the operation of the fuel supply control device 100 for the stratified combustion internal combustion engine will be described. When an ignition switch (not shown) of the vehicle is turned on, various initial settings (initialization) necessary for executing the control program of the fuel injection device 100 are performed as shown in FIG. 3 (S100). Next, whether or not the learning flag indicating whether or not the injection timing correction learning has been performed is 1 is determined based on whether or not the vehicle (engine 20
It is determined whether or not (0) is immediately after shipment from the factory (vehicle manufacturer) or immediately after conversion of the vehicle battery 315 (S101). When it is determined that the conversion has just been performed, the variables TD, TG, and TH1 to TH4 that are set during the operation of the engine 200 are set in advance in R.
The value is set to the value stored in the OM 301 (S102).

TD indicates the injection timing dither amount, and T
G indicates one injection timing learning change amount, and TH1 to TH4
(Subscript numbers indicate cylinder numbers.) Indicates each cylinder (combustion chamber)
In this embodiment, TD is 0.5 in crank angle, TG is 0.5 in crank angle, and TH1 to TH4 are 0 in crank angle. .

On the other hand, if the learning flag is other than 1 and it is determined that the vehicle is not immediately after shipment or immediately after conversion of the vehicle battery 315, the variables TD and TG are set to R
The value is set to the value stored in the OM 301, and TH1 to TH4 are set to the values stored in the backup memory 314 (S103). Next, the dither timer N for determining whether to change the fuel injection timing to the retard side or the advance side is set to 1 (S104), and thereafter, the main routine for actually determining the fuel injection timing is performed. Transition. Less than,
The main routine will be described with reference to FIGS.

First, the detected values of the engine operating state detecting means for detecting the operating state of the engine 2 such as the sensors 104 to 107 are read (S200). Hereinafter, the engine speed calculated from the detected value of the crank angle sensor 105 will be described as NE, the intake air amount detected by the air flow sensor 104 will be described as Q, and the detected value detected by the A / F sensor 107 will be described. It is described as an air-fuel ratio A / F.

Next, based on the various detection values read in S200, the basic injection amount TAV, the basic injection timing TB, and the ignition timing S are determined by a map stored in the ROM 301 in advance.
T is determined (S201), and it is determined whether stratified combustion or premixed combustion is to be performed (S202). And when not performing stratified combustion (premix combustion),
Based on the basic injection timing TB, the actual fuel injection timing TR
1 to TR4 (subscripts indicate cylinder numbers) (S203), and the determined fuel injection timings TR1 to TR4.
The fuel is injected (premixed injection) by operating the injection valve 101 so as to be 4 (S204), and premixed combustion is executed by energizing the ignition plug 206 (S205).

On the other hand, when performing stratified charge combustion, 1 is added to the dither timer N (S206), and it is determined whether or not the value of the dither timer N is 5 (S207). When the value of the dither timer N is less than 5, the process proceeds directly to S209. When the value of the dither timer N is 5, the value of the dither timer N is reset to 1 and then the process proceeds to S209.
The process proceeds to 209 (S209).

At S209, the basic injection timing TB
Is added to each cylinder injection timing correction amount THi (i indicates a cylinder number) to determine a tentative injection timing Ti (i indicates a cylinder number). Next, the dither direction Ki (i indicates the cylinder number) for each cylinder (combustion chamber) with respect to the value of the dither timer N stored in the ROM 301 in advance is determined (S210).

Here, the direction of the dither is 1 when the fuel injection timing is changed to the advanced side, and the direction of the dither is-.
1 indicates a case where the fuel injection timing is changed to the retard side.
FIG. 6 is a table (Table) showing the dither direction Ki for each cylinder with respect to the value of the dither timer N.
As is clear from this figure, the dither directions Ki of all the cylinders (combustion chambers) are set so as not to coincide. Note that the description of Table (N) in S209 indicates the dither direction Ki when the value of the dither timer N is N.

Next, the product of the injection timing dither amount TD and the dither direction Ki is added to the provisional injection timing Ti (Ti + TD × Ti).
Ki) The fuel injection timing TRi is determined (S211), and the injection valve 101 is set so as to reach the determined fuel injection timing TRi.
Is operated to inject fuel (stratified injection) (S
212), the ignition plug 206 is energized to perform combustion (S213).

Then, the combustion state determination means (combustion quality determination circuit 313, ion detection circuit 312) determines the combustion state (whether or not a fire has occurred) of each cylinder (combustion chamber) (S214). For the determined cylinder, the next cylinder injection timing correction amount THi is a value obtained by adding the product of the dither direction Ki, the injection timing learning change amount TG, and −1 to the current cylinder injection timing correction amount THi. (S215, S216).

The reason why the product of the dither direction Ki and the injection timing learning change amount TG is multiplied by -1 is to learn the fuel injection timing in a direction opposite to the dither direction Ki of the misfired cylinder. is there. Note that the injection timing learning change amount TG is a value (for example, 3 degrees or less in crank angle) at which the torque of the engine 2 does not greatly change. Next, it is determined whether or not the engine 2 has stopped based on the state of the ignition switch (S217). When the engine 2 has stopped, the learning flag is set to 1 (S218), and
The cylinder injection timing correction amount THi in the state of S217 is stored in the backup memory 314. On the other hand, engine 2
Is not stopped (operating), the process returns to S200.

FIG. 7 shows the control logic of the flowchart shown in FIGS. 3, 4 and 5 (the fuel supply control device for a stratified combustion internal combustion engine according to the present embodiment), and the outline thereof will be described below. . Note that parentheses indicate control steps corresponding to the flowcharts shown in FIGS. First, the engine operating state is detected in S1 (S200), and the combustion method is selected in S2 according to the operating state (S201,
S202). Then, when the accelerator opening of the occupant (driver) is large and a high output is demanded of the engine 2, the premix combustion method of S3 is selected, and the fuel injection amount and the injection timing TRi are determined ( S203), S4
Is executed (S204).

On the other hand, when the accelerator opening of the occupant (driver) is small, or when the engine 2 requires a relatively small output, such as when operating at a constant speed,
In S5, the stratified combustion system is selected. Then, the fuel injection amount and the temporary injection timing Ti are calculated from a map of the engine load and the number of revolutions stored in the ROM in advance (S209).
In the next S6, the injection timing dither amount TD is added to the provisional injection timing Ti.
The fuel injection timing TRI is determined by adding the product of the dither direction Ki and the dither direction Ki (S210). In S7, the dither correction amount (in which the advance and the retard of the injection timing of each cylinder are repeated every predetermined time) is repeated. The product of the injection timing dither amount TD and the dither direction Ki is added (S211). Note that the cylinder injection timing correction amount THi uses a value stored in the battery backup 314.

At this time, in S8, the combustion state detecting means detects the quality of combustion in each cylinder. For the cylinders with poor combustion, the dither direction (advance or retard) Ki of the poor combustion cylinder is determined in S9. Changes the injection timing correction amount THi,
The injection timing TRi of the cylinder having poor combustion is learned and changed so as to improve combustion (S214 to S216). As a result, the cylinder injection timing correction amount THi always becomes equal to the injection timing TRi.
Is changed to an appropriate value.

FIG. 8 is a chart showing an example of a learning change of the fuel injection timing in the first cylinder.
(A) shows the basic injection timing TB (in this embodiment, the 54 ° crank angle before the top dead center of the explosion), (b) shows the injection timing correction amount TH1, and (c) shows whether or not a misfire has occurred. (D) shows the tentative injection timing T1, (e) shows the product of the injection timing dither amount TD and the dither direction Ki (hereinafter, this product is referred to as dither correction amount), and (f). Indicates the fuel injection timing TR1.

At the time indicated by (a) in (b), the injection timing correction amount TH1 indicates 0 degree. Therefore, the tentative injection timing T1 is calculated from 54 degrees (= TB + TH1) (see c of (d)), the dither correction amount becomes 0.5 degrees (see d of (e)), and the fuel injection timing is obtained. TR1 is 54.5 degrees (= T1 + TD × K1) (see (f)). Incidentally, the dither correction amount (dither direction) is 0.5, -0.5, -0.5, 0.5, 0.5,-
0.5, -0.5 (see (e)).

Here, if it is determined that the first cylinder has misfired (see (c)), the dither direction at the time of the misfire is -1, so that the injection timing correction amount TH1 is equal to the aforementioned value. (TH1 = TH1−K1 × TG = 0 − (− 1)
× 0.5), learning is changed to +0.5. Similarly, when it is determined that the first cylinder has misfired again at the next time (time (c)), the injection timing correction amount TH1 (= TH1−K1 ×
TG = 0.5 − (− 1) × 0.5) is learned and changed to 1 (see (b)). Thereafter, by repeating the same learning change, the injection timing correction amount TH1 is changed to 2.5 (see (b)). Incidentally, the fuel injection timing TR1 at this time is 52.5 degrees.

It should be noted that the injection timing correction amount TH that is learned and changed
Accordingly, the provisional injection timing T1 (= TB + TH1) also changes in response to T1 and accordingly, the TR1 = T1 + TD × K1 corresponding to the provisional injection timing T1 and the dither correction amount TD × K1. The calculation includes the quantity TD × K1. FIG. 9 is a chart showing an example of a learning change of the fuel injection timing in the second cylinder. FIG. 9A shows the basic injection timing TB (in the present embodiment, 54% before the top dead center of the explosion).
(Crank angle), (b) shows the injection timing correction amount TH2, (c) shows whether or not a misfire has occurred, and (d)
Indicates the provisional injection timing T2, (e) indicates the dither correction amount, and (f) indicates the fuel injection timing TR2.

The basic injection timing TB is set to 54 degrees. Thereafter, when misfire is determined, the injection timing correction amount TH2 is learned and changed just like the first cylinder. More specifically, since the misfire is detected (see (a) in (c)) and the dither direction K2 at that time is -1 (see (a) in (e)), the injection timing correction amount TH2 is TH2−K1 × TG. =
Learning is changed from 0 − (− 1) × 0.5 = 0.5 to 0.5. Thereafter, if misfire is determined again (see (c)), the injection timing correction amount TH2 is again learned and changed.
It becomes 0.

FIG. 10 is a chart showing an example of the learning change of the fuel injection timing in the third cylinder. FIG. 10A shows the basic injection timing TB (in this embodiment, 54% before the top dead center of the explosion).
(Crank angle), (b) shows the injection timing correction amount TH3, (c) shows whether or not a misfire has occurred, and (d)
Indicates the provisional injection timing T3, (e) indicates the dither correction amount, and (f) indicates the fuel injection timing TR3.

In the third cylinder, the basic injection timing TB is set to 54 degrees, just like the first and second cylinders. Thereafter, when misfire is determined, the injection timing correction amount TH2 is learned and changed. . Note that, in the present embodiment (FIG. 8), an example in which a misfire is never detected is shown, the injection timing correction amount TH3 continues to be 0, and the basic injection timing TB remains at 54 degrees.

FIG. 14 is a chart showing an example of a learning change of the fuel injection timing in the 114th cylinder, in which (a) shows the basic injection timing TB (in the present embodiment, the 54 ° crank angle before the top dead center of the explosion). (B) shows the injection timing correction amount T
Hc, (c) indicates whether or not a misfire has occurred, (d) indicates a tentative injection timing T4, (e) indicates a dither correction amount,
(F) shows the fuel injection timing TR4.

When misfire is determined (see (c)), since the dither direction K4 is 1, the injection timing correction amount TH4 is -0.5 (= TH4-K4.times.TG).
= 0-1 x 0.5) is changed (see c in (b)). When misfire is determined again (see (c) d), since the dither direction K4 is 1, the injection timing correction amount T
H4 is -1.5 (= TH4-K4 × TG = -0.5-1)
× 0.5). Thereafter, when misfire is further determined, the injection timing correction amount TH4 is learned and changed to -1.5 based on the dither direction K4 (= 1) at that time. Incidentally, the fuel injection timing TR4 at this time is 52.5
Degrees.

By the learning change described above (FIGS. 8 to 11)
), The fuel injection timing TRi is the basic injection timing TB (=
54 degree), the first cylinder has a 2.5 degree advance correction,
No. 2 cylinder has a 1.0-degree advance angle side correction, No. 3 cylinder does not require correction, and No. 4 cylinder has a 1.5-degree retard angle side correction. Next, features of the present embodiment will be described.

According to this embodiment, when the combustion state determining means (312, 313) determines that the combustion state of the combustion chamber CC (cylinder) has deteriorated, the combustion state determining means (312, 313) determines. The fuel injection timing TRi is corrected on the basis of the above equation. Therefore, even if the actual fuel injection timing slightly varies due to the product variation of the fuel supply control device 100 for the stratified combustion internal combustion engine,
The fuel injection timing is corrected. Therefore, since the variation in the combustion state can be suppressed, the variation in the combustion state can be suppressed while preventing an increase in the manufacturing cost of the fuel supply control device 100 for the stratified combustion internal combustion engine.

Since the combustion state is constantly changing due to the secular change of the fuel supply control device 100 of the stratified combustion internal combustion engine, the correction value of the previous fuel injection timing can be effectively applied as it is from this time. There is no guarantee that they can. On the other hand, in the present embodiment, S206 to S2
Since the combustion state of the combustion chamber CC is determined by the combustion state determination means (312, 313) after the fuel injection timing is changed by 11, the fuel injection timing is constantly changed while the fuel injection timing TRi is changed. Can be corrected to the optimal direction. Therefore, it is possible to suppress the variation of the combustion state over a long period of time without being affected by the aging of the fuel supply control device 100 of the stratified combustion internal combustion engine.

Since the injection timing correction amount THi corrected in S216 is stored in the backup memory 314, a new injection timing correction amount THi (fuel injection timing TRi) is determined based on the previous injection timing correction amount THi. Therefore, the fuel injection timing TRi can be efficiently and properly corrected in a short time. The dither direction K
Since the fuel injection timing TRi (dither correction amount) is changed so that i differs for each combustion chamber CC (cylinder), the dither direction Ki (dither correction amount) overlaps (coincides) in each combustion chamber CC. Can be prevented. Therefore, since the torque fluctuation and vibration of the engine 2 can be prevented from increasing, the fuel injection timing TRi can be corrected in an appropriate direction without giving the occupant a discomfort.

Further, since the fuel injection timing TRi in each combustion chamber CC is corrected in an appropriate direction, the variation in the combustion state between each combustion chamber CC (each cylinder) can be reduced. Vibration and noise can be reduced, and the driving performance (drivability) of the vehicle can be improved. (Second Embodiment) In the first embodiment, the fuel injection timing TRi is corrected in an appropriate direction based on the combustion state of the combustion chamber CC. However, in the present embodiment, in addition to the combustion state of the combustion chamber CC, FIG. As shown in FIG. 11, the injection timing TRi is configured to be corrected in an appropriate direction for each region of the operating state of the engine 2 according to the operating state (rotational speed, load) of the engine 2.

In the above embodiment, the combustion state is determined by the ionic current generated between the electrodes of the ignition plug 206. However, the combustion state determination means according to the present invention is not limited to this. Means for providing an in-cylinder pressure sensor in the chamber CC to detect in-cylinder pressure; means for providing a combustion light sensor in the combustion chamber CC to detect combustion light; means for detecting exhaust gas concentration (eg, HC concentration) in an exhaust pipe; The combustion state may be detected by other means such as a means for detecting the exhaust gas concentration (eg, O ₂ concentration), a means for detecting the generated torque of the engine 2, a means for detecting a change in the rotation speed of the engine 2, and the like.

The fact that the combustion state of the combustion chamber CC has deteriorated is not limited to the misfire state, and it may be determined that the combustion state has deteriorated incomplete combustion that does not lead to misfire.
Note that the deterioration of the combustion state includes partial combustion (a combustion state in which combustion occurs halfway and disappears halfway), and detection of this partial combustion may be used. In the above-described embodiment, the fuel is directly injected (supplied) into the combustion chamber CC by disposing the injection valve (fuel supply valve) 101 in the combustion chamber CC. However, the present invention is not limited to this. However, the present invention can also be applied to an engine of a type in which the injection valve 101 is disposed in an intake pipe and is supplied directly into the combustion chamber CC from an intake port of intake air of the combustion chamber CC.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a fuel supply control device for a stratified combustion internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of an electronic control device.

FIG. 3 is a flowchart showing a control flow of a fuel supply control device for a stratified combustion internal combustion engine.

FIG. 4 is a flowchart showing a control flow of a fuel supply control device for a stratified combustion internal combustion engine.

FIG. 5 is a flowchart showing a control flow of a fuel supply control device for a stratified combustion internal combustion engine.

FIG. 6 is a table showing a dither direction Ki for each cylinder with respect to a dither timer N;

FIG. 7 is a block diagram showing a control flow of a fuel supply control device for a stratified combustion internal combustion engine.

8A is a chart showing a basic injection timing TB of a first cylinder, and FIG. 8B is a chart showing an injection timing correction amount TH of a first cylinder.
1, (c) is a chart showing whether the first cylinder has misfired, (d) is a chart showing the temporary injection timing T1 of the first cylinder, and (e) is a chart showing the temporary injection timing T1. 4 is a chart showing a dither correction amount of a cylinder, and (f) is a chart showing a fuel injection timing TR1 of a first cylinder.

9A is a chart showing a basic injection timing TB of a second cylinder, and FIG. 9B is a chart showing an injection timing correction amount TH of a second cylinder.
2, (c) is a chart showing whether the second cylinder has misfired, (d) is a chart showing the tentative injection timing T2 of the second cylinder, and (e) is a chart showing the second cylinder. 4 is a chart showing a dither correction amount of a cylinder, and (f) is a chart showing a fuel injection timing TR2 of a second cylinder.

10A is a chart showing a basic injection timing TB of a third cylinder, and FIG. 10B is a chart showing an injection timing correction amount T of a third cylinder.
FIG. 7C is a chart showing H3, FIG. 7C is a chart showing whether or not the third cylinder has misfired, FIG. 9D is a chart showing the temporary injection timing T3 of the third cylinder, and FIG. 4 is a chart showing a dither correction amount of a cylinder, and (f) is a chart showing a fuel injection timing TR3 of a third cylinder.

11A is a chart showing a basic injection timing TB of a fourth cylinder, and FIG. 11B is a chart showing an injection timing correction amount T of a fourth cylinder.
FIG. 4C is a chart showing H4, (c) is a chart showing whether or not the fourth cylinder misfired, (d) is a chart showing the temporary injection timing T4 of the fourth cylinder, and (e) is a chart showing the fourth cylinder. 4 is a chart showing a dither correction amount of a cylinder, and (f) is a chart showing a fuel injection timing TR4 of a fourth cylinder.

FIG. 12 is a map showing a relationship between a rotational speed, an engine load, and an injection correction amount for each cylinder.

FIG. 13 is a schematic diagram showing a stratified combustion state.

FIG. 14 is a schematic diagram showing a premixed combustion state.

[Explanation of symbols]

101: fuel injection valve, 206: spark plug, 300: electronic control unit.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI F02D 45/00 312 F02D 45/00 312T 368 368Z F02P 17/12 F02P 17/00 F (72) Inventor Masao Kano Nishio City, Aichi Prefecture 14 Iwatani, Shimowa-Kadomachi Japan Auto Parts Research Institute, Inc. (72) Inventor Ma Masaki Satoshi 14 Iwatani, Shimowa-Kakucho, Nishio-shi, Aichi Prefecture Inside Japan Automotive Components Research Institute, Inc. 1 Toyota Town, Toyota City, Japan

Claims (7)

[Claims] 1. A fuel supply control device for a stratified combustion internal combustion engine capable of supplying fuel directly to a combustion chamber having an ignition plug and capable of stratified combustion, comprising: a fuel supply valve for supplying fuel into the combustion chamber; Combustion state determination means for determining the combustion state of the combustion chamber; and when the combustion state determination means determines that the combustion state of the combustion chamber has deteriorated, a fuel supply timing based on the determination by the combustion state determination means. And a supply timing correcting means for correcting the fuel pressure. 2. The fuel supply system according to claim 1, further comprising: a supply timing changing unit that changes a fuel supply timing to a predetermined amount in a direction of retarding or advancing the fuel supply timing during operation of the stratified combustion internal combustion engine, wherein the fuel supply timing is changed by the supply timing changing unit. 2. The fuel supply control device for a stratified combustion internal combustion engine according to claim 1, wherein the combustion state of the combustion chamber is determined by the combustion state determination unit. 3. The supply time correction means, when the fuel supply time is changed by the supply time change means, and when the combustion state determination means determines that the combustion state of the combustion chamber is deteriorated, the supply time correction means performs the supply. 3. The fuel supply control device for a stratified combustion internal combustion engine according to claim 2, wherein the fuel supply timing is changed in a direction opposite to the direction of the change changed by the timing changing means. 4. A storage means for storing the fuel supply timing corrected by the supply timing correction means even after the stratified combustion internal combustion engine is stopped, and when the stratified combustion internal combustion engine is restarted after the stop. 2. The fuel supply timing is newly determined based on the fuel supply timing stored by the storage means.
4. The fuel supply control device for a stratified combustion internal combustion engine according to any one of the above-described items 3 to 3. 5. The fuel supply timing corrector corrects a fuel supply timing in consideration of an operation state of the stratified combustion internal combustion engine in addition to the determination by the combustion state determiner. 5. The fuel supply control device for a stratified combustion internal combustion engine according to any one of 4. 6. The fuel supply for a stratified combustion internal combustion engine according to claim 1, wherein said combustion state determination means makes a determination based on an ionic current generated in said combustion chamber. Control device. 7. A multi-cylinder stratified combustion internal combustion engine in which the fuel supply control device for a stratified combustion internal combustion engine according to any one of claims 2 to 6 is applied to a stratified combustion internal combustion engine having a plurality of combustion chambers. The fuel supply control device according to claim 1, wherein the supply timing changing means changes the fuel supply timing so that the direction of change of the fuel supply timing changed by the supply timing changing means is different for each combustion chamber. A fuel supply control device for a multi-cylinder stratified combustion internal combustion engine.