JPH0586948A - Control device for inter-cylinder fuel-injection type engine - Google Patents

Abstract

PURPOSE:To produce an optimum fuel-air mixture layer and to perform proper matching of an ignition timing by controlling the ignition timing of an ignition plug based on a detected result of the injection completion period of an injection valve. CONSTITUTION:In control of a heat accumulation type injection pump 14, when the load and the number of revolutions of an engine are in a high load high rotation region, an injection pressure is set to a high value, and when they are in a low load low rotation region, it is set to a low value. In control of an injection valve 12, engine injection and an injection starting period are set based on a map wherein the number of revolutions and the load of an engine produces a parameter. In relation to the ignition timing of an ignition plug 11, when an injection pressure is set to a low value, control is effected based on a map wherein the number of revolutions and the load of an engine produce a parameter. However, when an injection pressure is set to a high value, after an actual injection completion timing is detected, an ignition timing correction amount is determined based on a correction map wherein the number of revolutions and the load of an engine work as parameters at this timing, and at an injection completion time, the ignition timing correction amount value is added to decide an ignition timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a cylinder fuel injection engine.

[0002]

2. Description of the Related Art Recently, in-cylinder fuel injection type engines have been attracting attention from the viewpoint of measures against exhaust gas and fuel consumption. In this in-cylinder fuel injection type engine, the actual open sho 58-154825
As disclosed in the publication, a fuel injection valve for directly injecting fuel into the combustion chamber and a spark plug are provided to ignite the air-fuel mixture stratified in the combustion chamber.

That is, in the in-cylinder fuel injection engine, the output is adjusted not by the throttle valve (intake air amount).
It is supposed to be performed by the fuel supply amount, and in simple terms, it is necessary to form a rich air-fuel mixture layer around the spark plug to promote ignition. Therefore, in this type of engine, how to generate an optimum air-fuel mixture layer according to the operating state, in other words, matching the generation of the optimum air-fuel mixture layer and the ignition timing is a major technical problem. Is becoming

[0004]

Under the above technical problems, it is preferable to inject a necessary injection amount in a short injection time because, for example, it is impossible to take a sufficient time for injection in a high rotation region. .. In order to meet such a demand, it has been considered to make the injection pressure of the fuel injection valve variable so as to have a high injection pressure in the above case, that is, in the high rotation region. That is, it is considered that the base injection pressure is set as low as possible in order to reduce the mechanical loss of the injection pump, while the injection pressure is changed to a high pressure as needed.

However, when the injection pressure is changed in this way, the injection period changes in accordance with the change of the injection pressure (in the case of supplying the required amount of fuel, the injection time can be shortened when the injection pressure is increased. Therefore, there is a new problem that it becomes difficult to match the generation of the optimum mixture layer with the ignition timing.

Therefore, an object of the present invention is to make the injection pressure of the fuel injection valve variable and to optimize the matching between the generation of the optimum mixture layer and the ignition timing. It is to provide a control device for an engine.

[0007]

SUMMARY OF THE INVENTION In order to achieve such a technical problem, in the present invention, by optimizing the time between the end-of-fire timing and the ignition timing, the optimum mixture layer at the ignition time can be formed. The following configuration is adopted based on the recognition that it can be generated. That is, the spark plug arranged facing the combustion chamber, and the spark plug arranged facing the combustion chamber,
A fuel injection valve for injecting fuel directly into the combustion chamber, an injection end detection means for detecting a fuel injection end timing of the fuel injection valve, and an ignition control means for controlling an ignition timing of an ignition plug based on the injection end detection means. And is provided.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, reference numeral 1 is an in-cylinder fuel injection engine, and the engine 1 has a cylinder block 2 and a cylinder head 3. A cylinder bore 4 is formed in the cylinder block 2, and a piston 5 is slidably fitted in the cylinder bore 4. In the piston 5,
A recess 5a is provided on the top surface, and the combustion chamber 6 is defined by the piston 5 and the cylinder head 3.

A combustion chamber 6 is provided in each of the cylinder heads 3.
An intake port 7 and an exhaust port 8 which open to the inside are formed, an intake valve 9 is provided in the intake port 7, and an exhaust valve 10 is provided in the exhaust port 8. There is. Further, a spark plug 11 and a fuel injection valve 12 are arranged so as to face the combustion chamber 6, the spark plug 11 and the fuel injection valve 12 are held by the cylinder head 3, and the fuel injection valve 12 has an injection hole. 1
2a is directed to the gap 11a of the spark plug 11.

A fuel supply pipe 13 is connected to the fuel injection valve 12, and a pressure accumulation type injection pump 14 is connected to an upstream end of the fuel supply pipe 13. This accumulator injection pump 1
4 has a bypass valve (not shown), and by controlling the opening / closing of this bypass valve, the fuel supply pressure, that is, the injection pressure of the fuel injection valve 12 can be adjusted in two stages, high pressure and low pressure. Such a pressure-accumulation pump has been conventionally known, and therefore detailed description thereof will be omitted.

In FIG. 1, reference numeral 20 is a control unit, and the control unit 20 is composed of, for example, a microcomputer, and as is well known, a CPU and RO.
It is equipped with M and RAM.

Signals from the sensors 21 to 24 are input to the control unit 20. The sensor 21
Is for detecting the engine speed N. The sensor 22 detects the engine load based on the accelerator pedal depression amount (accelerator opening Th) not shown. The sensor 23 is a lift sensor that detects the closing timing of the movable valve body of the fuel injection valve 12. The sensor 24 detects the actual injection pressure of the fuel injection valve 12 from the internal pressure of the fuel supply pipe 13. The control unit 20
From, a control signal is output to the spark plug 11, the fuel injection valve 12, and the pressure-accumulation injection pump 14.

The contents of the control performed by the control unit 20 will be described below. First, the outline of the control will be described. In the control of the pressure-accumulation injection pump 14, that is, the control of the injection pressure P, the injection pressure is set to a high pressure when the engine speed is in a high rotation range as shown in FIG.
The injection pressure is set to a low pressure when the engine speed is in the low speed range. This makes it possible to shorten the fuel injection period in the high rotation speed region.

Similarly, when the engine load is in the high load region, the injection pressure is set to a high pressure, and when the engine load is in the low load region, the injection pressure is set to a low pressure. As a result, the penetrating force of fuel injection in the high load operation region can be increased, and the mixing of fuel can be improved. The above injection pressure control is specifically performed based on the control map shown in FIG.

As shown in FIG. 2, the injection pressure is changed by providing a hysteresis between switching from low pressure to high pressure and switching from high pressure to low pressure. That is, taking the engine speed as an example, the engine speed increases and the first predetermined value (N ₁ , Th _{1 in} the case of engine load)
When the engine speed becomes low, the high pressure is switched to the high pressure. When the engine speed decreases and reaches the second predetermined value (N ', Th' in the case of engine load), the high pressure is switched to the low pressure. And the first predetermined value (N ₁ or Th ₁ ) and the second predetermined value (N ′ or Th ′).
The value is different from. The first predetermined value (N ₁ or Th ₁ ) is set to a value larger than the second predetermined value (N ′ or Th ′). For example, if the engine speed is explained, the engine speed decreases. In the operating state, the dead zone is between the first predetermined value (N ₁ ) and the second predetermined value (N ′).

By setting the first predetermined value (N ₁ or Th ₁ ) and the second predetermined value (N 'or Th') to different values, the engine operating condition (engine speed and engine load) can be controlled to some extent. It is possible to prevent the injection pressure changing control from being frequently performed in response to the fluctuation of the control pressure, and to prevent the control from becoming unstable.

Next, the outline of the control of the fuel injection valve 12 will be described. The injection period (Δt) and the injection timing (injection start timing tig) of the fuel injection valve 12 are shown in FIG.
Alternatively, the control is performed based on the control map shown in FIG.

The control of the spark plug 11 will be briefly described below. When the injection pressure is set to a low pressure, the ignition timing Tig of the spark plug 11 is controlled based on the control map shown in FIG. On the other hand, when the injection pressure is set to a high pressure, the ignition timing T of the spark plug 11
With regard to ig, the ignition timing is adjusted according to the actual injection end timing after detecting the timing when the fuel injection is ended.

Based on the above, the fuel injection valve 12
A specific example of the ignition timing control with respect to the injection pressure change control will be described based on the flowchart shown in FIG. First,
In step S1 (hereinafter, each step is represented by adding a symbol "S" to the step number), the engine speed N and the throttle opening T as an engine load are set.
Input h. For convenience of description (for easy understanding), the steps after S2 will be described by dividing them into typical operating states.

(1) The engine speed increases or
When the gin load increases, in S2, the previous engine speed N ₀ (or the throttle opening Th ₀ ) is compared with the current engine speed N (or the throttle opening Th), and the engine speed is in the deceleration state (or the throttle opening Th). It is determined whether or not the opening degree is decreasing. Since the engine speed is now in the speed increasing state (or the load is increasing), it means NO in S3.
Proceeding to the subsequent steps, various control maps (see FIGS. 3 to 5 described above) are read. And S6
At, the injection pulse is output to the fuel injection valve 12.

At the next step S7, it is judged whether or not a high pressure is set as the injection pressure P. If NO, then
That is, when the low pressure is set, the routine proceeds to S8, the ignition timing basic control map (see FIG. 6 described above) is read, and the ignition of the spark plug 11 is executed at S9.

On the other hand, when YES is determined in the above S7, that is, when the high injection pressure P is set, the injection end timing teg is detected (sensor 23) in S10.
Based on the signal from) is performed. And next S1
In 1, the ignition timing correction amount tct is read from the map shown in FIG. The parameters of the ignition timing correction amount tct are engine speed N and engine load Th, as is apparent from FIG.

In the next S12, the ignition timing Tig is calculated based on the following equation, and thereafter the ignition is executed in S9 based on the calculated value.

Ignition timing calculation formula: Tig = teg + tct where: teg: actual injection end timing as described above tct: map value of ignition timing correction amount as described above

After the ignition is executed in S9, S
In step 13, it is determined whether the injection pressure P has been changed from low pressure to high pressure. Now, for example, if the engine speed N exceeds the first predetermined value N ₁ (see FIG. 2) (when the injection pressure is switched to high pressure), the routine proceeds to S14, where the flag F is set ( F = 1) is performed. On the other hand,
When the injection pressure is not changed, the process proceeds to S15, and the flag F is reset (F = 0).

(2) Engine speed or engine negative
When the load does not change (steady state) In such an operating state, NO is determined in S2. Therefore, the process proceeds from S2 to S3 and subsequent steps, and the above-described processing is performed. Here, in S13, the answer is NO, so the process proceeds to S15, and the flag F is reset (F = 0).

(3) The engine speed is decelerated or
When the gin load decreases, in such an operating state, it is first determined to be NO in S2, and therefore the process proceeds to S16, and it is determined whether or not the flag F is in the set state "F = 1". .. If YES in S16, that is, if the injection pressure is in the high pressure state, the routine proceeds to S17, where it is determined whether the engine speed N (or the throttle opening Th) is smaller than the second predetermined value N '(or Th'). If the determination is NO, the engine speed N (or throttle opening Th) is determined by the first predetermined value N ₁ (or Th ₁ ) and the second predetermined value N ′ (or Th ′). If it is in the middle, the routine proceeds to S18, where the injection pressure P, the injection period Δt, the injection timing (injection start timing tig) are set to the previous value P _0, etc., and then the routine proceeds to S6, where fuel injection is performed.

Second Embodiment In this embodiment, the injection pressure of the fuel injection valve 12 is set to a high pressure in the idle operation state, and the ignition timing Tig is set by calculation as in the first embodiment (see FIG. 7 steps S10 to S12). This allows
It is possible to blow away the carbon adhering to the ignition plug 11 by the fuel vigorously injected from the fuel injection valve 12, and it is possible to prevent smoldering during idle operation.

Further, the injection start timing tig may be retarded as the injection pressure is increased. That is, the fuel injection pressure during idle operation may be increased to shorten the injection period Δt, and the shortened injection period Δt may be directed to the ignition side. According to this, the fuel is injected at a high pressure at a time when the in-cylinder pressure (increase of the in-cylinder pressure due to the compression stroke) and the in-cylinder temperature are high, and it is possible to improve the mixing of the fuel and thus the ignition. Of course, since the spark plug 11 is not always smoldered during idle operation, the injection pressure control and the injection start timing control described above are performed intermittently at regular intervals (for example, every 100 cycles).
Times), usually, a low injection pressure may be set.

Third Embodiment While the engine is cold, the injection pressure of the fuel injection valve 12 is set to a high pressure, and the injection start timing tig is retarded as the injection pressure is increased. Then, as the injection pressure is increased, the ignition timing Tig is set by calculation as in the first embodiment (step S10 in FIG. 7).
~ S12). According to this, the fuel is injected at a high pressure when the in-cylinder pressure (increase of the in-cylinder pressure due to the compression stroke) and the in-cylinder temperature are high, and it is possible to improve mixing of the fuel during cold and thus ignition. Become.

Fourth Embodiment When the injection pressure is changed between a low pressure and a high pressure, in order to actually increase or decrease the injection pressure, as shown in FIG. 9 (a case of pressure increase is shown as a representative example). ), Time delay Δ
There is T (especially noticeable for boosting). In order to solve this problem, in the present embodiment, the injection period Δt of the fuel injection valve 12 is received by receiving the pipe pressure signal of the fuel supply pipe 13 from the sensor 24, that is, the actual injection pressure (map (FIG. 4)
Ignition timing Tig of the spark plug 11 to correct the injection period Δt and to adjust the injection period Δt.
(The value read from the map (FIG. 6)) is corrected.

Fifth Embodiment (FIG. 10) In this embodiment, the injection pressure is switched while the fuel injection valve 12 of a certain cylinder is opened in the above-described first embodiment and the like on the premise of another cylinder engine. If an injection pressure change command is issued during the opening period of the fuel injection valve 12, the injection is continued until the injection of the fuel injection valve 12 of the cylinder is completed. The pressure switching is stopped. A specific example of such control is shown in FIG.
0 is shown. In the flowchart shown in FIG. 10, the flag I is set (I = 1) while the fuel injection valve 12 is open, and reset (I = 0) when the fuel injection valve 12 is closed. ) Is done.

Sixth Embodiment (FIGS. 11 to 13) First, the structure of the engine 1 according to the present embodiment will be described with reference to FIG. The engine 1 according to the first embodiment
The same elements as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.
The characteristic part of will be described.

In this embodiment, a throttle valve 31 is provided in the intake passage 30 connected to the intake port 7, and the second fuel is provided in the intake passage 30 so as to face the intake port 7. The injection valve 32 is provided. The throttle valve 31 has an electric motor 33 as a drive source, and the throttle valve 31 and the accelerator pedal 34 are electrically connected. That is, a control signal is output from the control unit 20 to the electric motor 33, and the opening / closing control of the throttle valve 31 is performed based on this control signal. Reference numeral 35 shown in FIG. 11 is a throttle opening sensor for detecting the opening of the throttle valve 31. Further, reference numeral 36 is a fuel tank. Reference numeral 37 is an air cleaner.

In this embodiment, in-cylinder injection using the first fuel injection valve 12 and intake system injection using the second fuel injection valve 32 are performed. FIG. 12 is a map for switching control between in-cylinder injection and intake system injection, and shows an area I (low rotation and low load area) and an area II shown in the map.
In I (high rotation and high load region), fuel is supplied by the intake system injection.

On the other hand, in the region II (medium-rotation medium-load region), the fuel is supplied by the in-cylinder injection. By the way, in the above intake system injection, the throttle valve 3
1 is opened almost corresponding to the accelerator opening. On the other hand, in the in-cylinder injection, the throttle valve 31 is kept fully open.

That is, when the in-cylinder injection is adopted in the region I, the air-fuel mixture in the cylinder becomes a lean air-fuel mixture.
Considering that stable ignition is difficult to obtain, the intake system injection is adopted in this region I. Further, when the in-cylinder injection is adopted in the region III, the intake system injection is adopted in the region III in consideration of the fact that the driving resistance of the injection pump 14 becomes large because a high injection pressure is required as described above. It is a thing. On the other hand, since the in-cylinder injection is adopted in the region II, the pumping loss can be significantly reduced.

By the way, the required injection pressure differs between the case of injecting fuel into the cylinder in the high pressure state and the case of injecting fuel into the intake system in the low pressure state. That is, when injecting fuel into the intake system (when using the second fuel injection valve 32), a low injection pressure is sufficient, and when injecting combustion into the other cylinder (the first fuel injection valve 12 is When using)
The injection pressure must be high.

From the above, when switching from the intake system injection to the in-cylinder injection, it is necessary to increase the injection pressure. However, since it takes time to increase the injection pressure, there is a problem of response delay of the injection pressure. Occurs. To solve this problem, in the present embodiment, in the region I and the region III where the intake system injection is performed, the region adjacent to the region II (in-cylinder injection) (FIG. 1).
The area marked with diagonal lines 2) is the accumulator zone.

That is, referring to FIG. 13, the case of transition from the region I to the region II will be described as an example. For example, when the engine speed increases and the accumulator zone in the region I is entered, the control is performed. The low unit 20 outputs a switching control signal from low pressure to high pressure to the injection pump 14. Then, the injection pressure is increased to a predetermined high injection pressure within the accumulated pressure zone, and at the stage when the injection pressure is changed to the region II, a signal for switching from the intake system injection to the in-cylinder injection is sent from the control unit 20. Is output.

When shifting from the region II of the seventh embodiment (FIG. 12, in-cylinder injection) to the region I (FIG. 12, injection of the intake system), the throttle valve 31 is required to be closed from the fully open state to the state where it is greatly throttled. However, since this closing operation requires time, there is a problem that the engine output suddenly increases immediately after switching to the intake system injection due to the response delay of the throttle valve 31.

To cope with such a problem, in the present embodiment, in-cylinder injection is performed during the response delay period of the throttle valve 31. That is, after the transition from the region II to the region I, the switching to the intake system injection is performed when a predetermined delay time has elapsed. In addition, during the response delay period of the throttle valve 31, the filling amount decreases with the closing operation of the throttle valve 31, and when in-cylinder injection is performed under a low filling amount, fuel mixing is performed. Although a defect and deterioration of ignitability will be caused, as a countermeasure against this problem, the control of the second embodiment described above is performed in this embodiment.

That is, the control contents of the seventh embodiment will be listed below as time passes. (1) Detection of transition from region II to region I (2) Start of closing operation of the throttle valve 31 (3) Together with increase in injection pressure (4) Together with injection timing tig (5) Together with ignition timing Calculation of Tig (step S1 in FIG. 7)
0 to S12) (6) Completion of the closing operation of the throttle valve 31 (detected by the sensor 35) (7) Switching from in-cylinder injection to intake system injection (also reducing the injection pressure)

According to the above control, since the in-cylinder injection under a low filling amount is performed at a high injection pressure, it is possible to avoid the poor mixing of fuel and the deterioration of ignitability.

Eighth Embodiment Region I (FIG. 12, intake system injection) to region II (FIG. 12,
When shifting to in-cylinder injection), the problem of response delay of the injection pressure and the problem of response delay of the throttle valve 31 occur as described above. The following control is performed to solve this problem. The control contents of the eighth embodiment are listed below as time passes.

(1) Detection of transition from region I to region II (2) Start of injection pressure boosting (3) Detection that injection pressure has exceeded a predetermined pressure (almost in-cylinder injection pressure) (4) Intake system Switching from injection to in-cylinder injection (5) In addition, opening operation of throttle valve 31 is started (6) Injection pressure is further increased (7) Injection timing tig is also retarded (8) Ignition timing Tig is also calculated ( Step S1 of FIG.
0 to S12) (9) Detecting that the throttle valve 31 is in the fully open state (detected by the sensor 35) (10) Changing to normal in-cylinder injection (reducing the injection pressure to the normal injection pressure, S3 in FIG. 7) ~ In-cylinder injection control represented by S9)

In the above control, if the opening operation of the throttle valve 31 is started prior to the switching processing from the intake system injection to the in-cylinder injection in (4) above, the opening operation of the throttle valve 31 is accompanied. As a result, the problem that the engine output suddenly increases occurs, but the control of the present embodiment does not cause such a problem.

Ninth embodiment Region II (FIG. 12, in-cylinder injection) to region III (FIG. 1)
2, the intake system injection), the throttle valve 3
In No. 1, the closing operation is performed to slightly narrow down the fully opened state. However, since this closing operation is completed in a short time, the problem of the response delay of the throttle valve 31 unlike the seventh embodiment hardly occurs.

From the above, the region II (FIG. 12,
The control when transitioning from the in-cylinder injection) to the region III (FIG. 12, intake system injection) is listed as follows with the passage of time. (1) Detection of transition from region II to region III (2) Start of closing operation of throttle valve 31 (3) Decompression of injection pressure at the same time (4) Completion of closing operation of throttle valve 31 (detected by sensor 35) (5) Switching from in-cylinder injection to intake system injection

From the tenth embodiment region III (FIG. 12, intake system injection) to region II (FIG. 1)
2, in-cylinder injection), the throttle valve 31
Although the opening operation for opening the throttle valve 31 slightly is performed from the state in which it is wide open to the fully open state, the opening operation of the throttle valve 31 is completed in a short time, so the throttle valve 31 as in the eighth embodiment is opened. There is almost no problem of delay in response.

From the above, the region III (see FIG.
The following is a list of controls when transitioning from the region (2, intake system injection) to the region II (FIG. 12, in-cylinder injection) with the passage of time.

(1) Detection of transition from region I to region II (2) Start of boosting of injection pressure (3) Detection that injection pressure has exceeded a predetermined pressure (substantially in-cylinder injection pressure) (4) Intake system Switching from injection to in-cylinder injection (control represented by S3 to S9 in FIG. 7) (5) At the same time, opening operation of the throttle valve 31 is started.

Eleventh Embodiment (FIG. 14) The cylinder fuel injection type engine 1 according to this embodiment is basically the same as the engine shown in FIG. Using a 2-core valve type fuel injection valve,
It is possible to switch between focus injection and hole injection. Here, as the two-core valve fuel injection valve, a type in which switching between focus injection and hole injection is adjusted by a spring constant of a spring for urging a needle valve is adopted. Since such a two-core valve fuel injection valve is known, detailed description thereof will be omitted.

The switching between the focus injection and the hole injection is basically performed based on the control map shown in FIG. 14, and in the map, in the low rotation and low load region I,
The fuel injection is performed by spraying the fuel in a wide range and is excellent in mixing, and in the region II which is the other region, the fuel injection is performed by spot injection that is spotwise.

Here, the switching control between the high pressure and the low pressure of the injection pressure P is provided with hysteresis as in the case of FIG. 2, and frequent injection between the focus injection and the hole injection is performed. Switching is avoided.

According to this embodiment, since the spring type two-core valve type fuel injection valve is used as the fuel injection valve 12,
Only by switching the injection pressure P between the high pressure and the low pressure, the focus injection and the hole injection are automatically switched.

[0057] For the twelfth embodiment the eleventh embodiment, if the original e - in the area are Le injection region I (Fig. 14), in the cold time injection pressure is set to a high pressure Pinto The ignition timing Tig is set by calculation (steps S10 to S12 in FIG. 7), and the injection start timing tig is set, as in the first embodiment. It is designed to be retarded. According to such control, atomization of the fuel in the cold state is improved, so that it becomes possible to improve the ignitability in the cold state.

Thirteenth Embodiment (FIG. 15) As shown in FIG. 15 , the engine according to the present embodiment is provided with two fuel injection valves 40 and 41 which are electromagnetic and face the combustion chamber 6. One of the fuel injection valves 40 is a focus injection type fuel injection valve, and the other fuel injection valve 41 is a hole injection type fuel injection valve. The injection hole 40 a of the fuel cell 40 is directed to the gap 11 a of the spark plug 11.

Switching between the two fuel injection valves 40 and 41, that is, switching between focus injection and hole injection,
Basically, it is performed based on the control map shown in FIG.

Further, the focus injection type fuel injection valve 40
And the hole injection type fuel injection valve 41 are individually controlled. That is, the focus injection valve 40
And the hole injection valve 41 respectively control the injection pressure based on the unique injection pressure control map, and the ignition timing is also controlled based on the unique ignition timing control map. It is supposed to be done.

Further, at the transitional transition between the focus injection and the hole injection, the steps S10 to S of FIG. 7 are performed.
The same processing as in 12 is performed to correct the ignition timing, thereby realizing stable and accurate ignition during the transition.

[0062]

As is apparent from the above description, according to the present invention, it is possible to set the ignition timing which is adapted to the actual injection end timing even if the injection pressure of the in-cylinder fuel injection is made variable. Therefore, the generation of the optimum mixture layer and the matching with the ignition timing can be optimized.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a cylinder fuel injection engine according to an embodiment.

FIG. 2 is a diagram showing an example (hysteresis) of injection pressure control.

FIG. 3 is a map used for injection pressure control in in-cylinder fuel injection.

FIG. 4 is a map used to control a fuel injection period in in-cylinder fuel injection.

FIG. 5 is a map used for controlling a fuel injection start timing in in-cylinder fuel injection.

FIG. 6 is a map used for ignition timing control in in-cylinder fuel injection.

FIG. 7 is a flowchart showing an example of in-cylinder fuel injection control and ignition timing control.

FIG. 8 is a map of a correction amount used for setting an ignition timing according to an actual fuel injection end timing.

FIG. 9 is a diagram showing the content of fuel injection pressure control in another embodiment.

FIG. 10 is a flow chart showing an example of injection pressure switching control in another embodiment.

FIG. 11 is a cross-sectional view showing a main part of an engine according to another embodiment.

FIG. 12 is a map used for injection pressure switching control in another embodiment.

FIG. 13 is an operation explanatory diagram of control performed based on the map of FIG. 12;

FIG. 14 is a map used for changing control of a fuel injection valve in another embodiment.

FIG. 15 is a sectional view showing a main part of an engine according to another embodiment.

[Explanation of symbols]

 5 Piston 6 Combustion chamber 9 Intake valve 11 Spark plug 12 Fuel injection valve 20 Control unit 23 Lift sensor 40 Focus injection type fuel injection valve 41 Hole injection type fuel injection valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // F02B 23/10 Z 9039-3G

Claims (1)

[Claims] 1. A spark plug disposed to face a combustion chamber, a fuel injection valve disposed to face the combustion chamber, for injecting fuel directly into the combustion chamber, and a fuel injection end of the fuel injection valve. An in-cylinder fuel injection engine control device comprising: an injection end detection means for detecting a timing; and an ignition control means for controlling an ignition timing of an ignition plug based on the injection end detection means.