JPS63138121A - Stratified combustion control device for engine - Google Patents

Abstract

PURPOSE:To improve acceleration response and the like, by a method wherein, during acceleration running in that shifting is effected from a low load area where stratified combustion of air-fuel mixture is effected to a high load area where uniform combustion of air-fuel mixture is effected, uniform combustion of air-fuel mixture is forcibly performed even in the low load area. CONSTITUTION:A title device is provided with a means 13, feeding fuel in a combustion chamber, and a means 34, detecting the running state of an engine. Further, it is provided with a means 40, performing stratified combustion of air-fuel mixture through control of the fuel feed means 13, and a means 41, performing uniform combustion of air-fuel mixture through control of the fuel feed means 13 when the engine is in a low load area. Moreover, it is provided with a means 42, detecting acceleration running of the engine, and a means 43, correcting control of the stratified combustion means 40 and the uniform combustion means 41 so that uniform combustion is effected by stopping stratified combustion during acceleration running. This constitution increases an engine output during the initial stage of acceleration running to achieve improvement of acceleration response and the like.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a stratified combustion control device for an engine that stratifies the combustion chamber so that the combustible mixture is unevenly distributed around the spark plug in the combustion chamber and burns the mixture. Regarding the improvement of

(Prior Art) Conventionally, as a stratified combustion control device for this type of engine, for example, as disclosed in Japanese Patent Laid-Open No. 60-36721, the operating state of the engine is detected and the engine output is controlled at low load. Due to low demand, a small amount of fuel is directly supplied to the combustion chamber from a fuel injection valve for stratified combustion placed facing into the combustion chamber, and this fuel is unevenly distributed around the spark plug in the combustion chamber to improve the air-fuel mixture. By performing stratified charge combustion, the air-fuel ratio of the air-fuel mixture is increased (lean) as a whole while ensuring combustion stability, improving fuel efficiency. At the same time, when the engine is under high load, stratified combustion of the above-mentioned air-fuel mixture is performed. At the same time, the fuel injector for uniform combustion located in the intake passage injects an amount of fuel according to the operating conditions to uniformly disperse the combustible mixture within the combustion chamber and achieve uniform combustion of the mixture. It is known that an increase in engine output is ensured by performing the following steps.

(Problem to be Solved by the Invention) However, when performing stratified combustion and uniform combustion of the air-fuel mixture depending on the operating conditions as in the conventional method described above, when acceleration operation is started in a low load range, first the low load Stratified combustion of the air-fuel mixture continues in the range, and the engine output does not increase much. Later, when the engine operating state shifts to the high-load range due to acceleration, uniform combustion of the air-fuel mixture takes place from this point on. The engine power will increase as desired, thus
There is a time lag in acceleration response at the start of acceleration driving, which causes frustration in that acceleration performance deteriorates.

The present invention has been made in view of the above, and its purpose is to forcibly convert the air-fuel mixture even in this low-load area, instead of performing stratified combustion of the air-fuel mixture, at the start of acceleration operation from a low load area. By performing uniform combustion, the engine output is increased at the start of acceleration operation, and acceleration response is improved.

(Means for solving the problem) In order to achieve the above object, the solving means of the present invention is as follows:
As shown in the figure, an engine that performs stratified combustion and uniform combustion of an air-fuel mixture, that is, a fuel supply means 13 that supplies fuel into a combustion chamber, is provided, and an operating state detection means 34 that detects the operating state of the engine; Upon receiving the output of the operating state detection means 34, when the engine operating state is in a low load range, the fuel supply means 13 is controlled so that the air-fuel mixture supplied into the combustion chamber is stratified, thereby performing stratified combustion of the air-fuel mixture. receiving the outputs of the stratified combustion means 40 and the operating state detection means 34;
When the engine operating state is in a high load range, the fuel supply means 13 is configured to make the air-fuel mixture supplied into the combustion chamber uniform.
The present invention is based on a stratified combustion control system for an engine, which is equipped with a uniform combustion means 41 that controls uniform combustion of the air-fuel mixture. and an acceleration operation detection means 42 for detecting the acceleration operation of the engine, and receiving the output of the acceleration operation detection means 42;
It is configured to include an acceleration control means 43 for correcting the control of the stratified charge combustion means 40 and the uniform combustion means 41 so as to stop stratified combustion and perform uniform combustion during acceleration operation in a low load range. is.

(Function) With the above configuration, in the present invention, in the low load range of the engine, the fuel supply means 13 is controlled by the stratified combustion means 40, and the air-fuel mixture supplied into the combustion chamber is mixed around the spark plug in the combustion chamber. Since stratified combustion of the air-fuel mixture is performed in a state where the air-fuel mixture is unevenly distributed, the air-fuel ratio of the air-fuel mixture increases as a whole while ensuring combustion stability, thereby improving fuel efficiency.

On the other hand, in the high load range of the engine, the fuel 1 supplying means 13 is controlled by the uniform combustion means 41, and the mixture is uniformly combusted in a state where the mixture supplied into the combustion chamber is uniformly distributed throughout the combustion chamber. is performed, thus ensuring an increase in engine output.

When the acceleration operation of the engine is started in a low load range, the acceleration control means 43 corrects the control of the stratified combustion means 40 and the uniform combustion means 41, so that even in this low load range, the air-fuel mixture Since the stratified charge combustion of the engine stops and uniform combustion of the air-fuel mixture takes place, the engine output increases significantly from the beginning of accelerated operation. Then, when the load shifts to a high load region due to acceleration, the uniform combustion means 41 controls the fuel supply means 13 as usual, and uniform combustion of the air-fuel mixture is performed, so that the engine output increases further. become. Therefore, it is possible to improve the acceleration response even during acceleration operation from a low load range.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

FIG. 2 shows the overall configuration of a stratified combustion control device for an engine according to the present invention, in which 1 is an engine, 2 is a piston rotatably fitted into a cylinder 3 of the engine 1, and has a recess 2a formed at the top; 4 is a combustion chamber whose volume is variable by the piston 2; 5 is connected to the atmosphere at one end via an air cleaner 6; One end of the intake passage 7 is open to the combustion chamber 4, and the other end is an exhaust passage opened to the atmosphere for discharging exhaust gas. A throttle valve 9 for controlling the amount of air is disposed, and the throttle valve 9 and the intake passage 5 downstream of the surge tank 8 supply fuel to the combustion chamber 4.
Fuel injection valve 10 for uniformly distributing and supplying fuel within the fuel injection valve 10
is located.

Further, at the top of the combustion chamber 4, there is provided an ignition plug 11 that faces the concave portion 2a of the piston 2 and ignites the air-fuel mixture in the combustion chamber 4, and a spark plug 11 that faces around the ignition plug 11 in the combustion chamber 4 and ignites the fuel. Fuel injection valves 12 for injecting and supplying fuel are arranged unevenly around the plug. The fuel injection valve 10 in the intake passage 5 and the fuel injection valve 12 in the combustion chamber 4 constitute a fuel supply means 13 for supplying fuel into the combustion chamber 4.

In the figure, 15 is an intake valve disposed at the opening of the intake passage 5 to the combustion chamber A, 16 is an exhaust valve disposed at the opening of the exhaust passage 7 to the combustion chamber 4, and 17 is an exhaust valve. This is a catalyst device for exhaust gas purification placed in the middle of the passage 7.

Further, a stepper motor 20 for adjusting the opening degree of the throttle valve 9 is connected to the throttle valve 9, and a fuel injection valve for uniform combustion is connected to the fuel @ sword valve 10 for uniform combustion. A fuel pump 22 is connected to the fuel injection valve 12 for stratified combustion via a regulator 21 that adjusts the fuel pressure to the stratified combustion fuel injection valve 10. On the other hand, an injection pump 23 that supplies fuel to the fuel injection valve 12 for stratified combustion is connected to the fuel injection valve 12 for stratified combustion. is connected. Further, an ignition coil 24 is connected to the ignition plug 11.

Roughly speaking, 28 is a load sensor that detects the load state of the engine 1, 29 is a rotation speed sensor that detects the engine rotation speed,
A TDC sensor 30 detects a reference position based on a predetermined angular position of the crankshaft of the engine 1 (for example, the top dead center position of a piston in a predetermined cylinder); a water temperature sensor 31 detects the engine cooling water temperature; and a reference numeral 32 detects the temperature of intake air. An intake air temperature sensor 33 is an accelerator pedal opening sensor that detects the opening of an accelerator pedal (not shown). This constitutes an operating state detection means 34.

The detection signals from the six sensors 28 to 33 are input to a controller 35 that includes a CPU, RAM, etc., and the controller 35 controls the stepper motor 20, the fuel injection valve 10 for uniform combustion, and the controller 35. The injection pump 23 and the ignition coil 24 are each controlled to adjust the throttle valve opening, the amount of fuel during uniform combustion, the injection timing, the amount of fuel during stratified combustion, the injection timing, and the ignition timing of the air-fuel mixture.

Next, the operation of the controller 35 is controlled as shown in FIGS.
The explanation will be based on the control flow shown in the figure. First, starting from the control flow shown in FIG. 3, in steps S1 and S2, the stratified combustion region flag V and the uniform combustion region flag W are set to rOJ.
At the same time, in step S3, the reception cycle of the signal from the TDC sensor 0 is measured S'1, and in step s4, the above sensors (load, engine speed, cooling water temperature, intake temperature, and accelerator pedal opening) are initialized. Input each detection signal from

In step S5, it is determined whether the combustion is in the stratified combustion region (low load region) or the homogeneous combustion region (high load region), as shown in FIG. 6, based on the load signal and the engine speed signal. ,
In the case of YES in the stratified combustion region, the value of the acceleration flag T (described later) is determined in step S6, and in the case of steady operation where T≠1 (No), the value of the stratified combustion region flag V is set to "1" in step S7.
'', and in step S8 the program proceeds to the throttle valve opening control routine shown in FIG. 4, where the opening of the throttle valve 9 is adjusted as appropriate in response to stratified charge combustion.

Thereafter, in step S9, the injection ff1Qf+ for stratified combustion from the injection valve 12 of the combustion chamber 4 is calculated to a predetermined value corresponding to the load as shown in FIG.
In step 3o, the plunger control sleeve of the injection pump 23 is controlled so that the fuel becomes ff1Qf+, and then, in step 3o, the injection pump 23's immediate piston is controlled so that the injection timing of the injection valve 12 is in the latter half of the compression stroke, and the process returns.

On the other hand, if NO is not in the stratified combustion region in step S5, that is, in the uniform combustion region (high load region), the process proceeds to step 312 and subsequent steps to perform uniform combustion of the air-fuel mixture. The area flag W is set to a value of "1", and at step 313 the program proceeds to the throttle valve opening control routine shown in FIG. 4, where the opening of the throttle valve 9 is adjusted as appropriate in response to uniform combustion.

Thereafter, in step 314, the fuel ff1Qfz from the injection valve 12 in the combustion chamber 4 is calculated to a very small amount for the purpose of preventing clogging, as shown in FIG. Fuel ff1 for uniform combustion of
After calculating Qf3 to increase according to the increase in load as shown in FIG. Then, in step 317, the timer piston of the injection pump 23 is controlled so that the injection timing of the injection valve 12 is in the first half of the intake stroke, and in step S18, the injection valve 10 of the intake passage 5 is controlled so that the injection timing of the injection valve 12 becomes mQfz. Waiting for the injection timing of the fuel for uniform combustion, the injection pulse Tp of this uniform fuel is injected in step 319, and the process returns.

Then, in the case of YES in the stratified combustion region in step S5, during the acceleration operation of YES with T=1 in step S6,
Stratified combustion of the air-fuel mixture after step S7 is not performed, and the process immediately moves to step 312 and after, and the injector 1 of the intake passage 5
Uniform combustion of the air-fuel mixture is performed by injecting and supplying fuel for uniform combustion from zero.

Next, to explain the throttle valve opening degree control routine in FIG. The opening degree of the valve 9 is as shown in FIG.
The TVI is controlled to almost the full-open value, the amount of intake air during stratified combustion of the air-fuel mixture is increased significantly, the air-fuel ratio is significantly increased (lean), and the engine turns. In addition, the above step S
In the NO uniform combustion region where ■≠1 at s+, step SS3
The opening degree of the throttle valve 9 is determined by the function f(
rpm, pe) increases, that is, the output increases, and returns.

Also, while the control flow shown in FIG. 3 is continuing, the control flow is interrupted at predetermined intervals to proceed to the interrupt flow shown in FIG. In step SI, the value of is initially set as the rOJ value.
2, the accelerator pedal opening degree θ is converted from A to D, and step S
At r3, it is determined whether or not the engine operating state has departed from the idle state. Only in the case of YES that the engine operating state has departed from the idle state, the acceleration flag T is set to the value "1" at step SI4. Also, in step Srs, the rate of change b of the accelerator pedal opening θ within the minute time α = (θ([)-〇(t-α)
)/α is greater than or equal to a predetermined value β corresponding to an acceleration state, and only when θ≧β (YES) is the acceleration operation, the acceleration flag T is set to the value “1” in step Srs.

First, the value of the acceleration flag T is determined in step SI7, and only in the case of acceleration operation when T=1 (YES), a minute amount of uniform combustion fuel is supplied from the injection valve 10 of the intake passage 5 in step S8. is injected asynchronously, the acceleration flag T is returned to the "O" value in step SI9, and the process returns.

Therefore, in the control flow of FIG. 3 above, step 8
5 to 3o receive the output of the operating state detection means 34,
When the engine operating state is in the stratified combustion range (low load range), the operation of the injection valve 12 in the combustion chamber 4 is controlled to
The amount of fuel for stratified combustion of fuel ff1Qf+ is directly supplied to the combustion chamber 4 in the latter half of the compression stroke, so that the air-fuel mixture supplied into the combustion chamber 4 is stratified and unevenly distributed around the spark plug 11 of the combustion chamber 4. A stratified combustion means 40 is configured to perform stratified combustion of the air-fuel mixture in the following state. Also, step Ss
, 312 to 319 receive the output of the operating state detecting means 34, and when the engine operating state is in the uniform combustion region (high load region), actuate and control the injection valve 10 of the intake passage 5. The fuel for uniform combustion of ff1Qf3 is injected and supplied to the combustion chamber 4 in the first half of the intake stroke, and the air-fuel mixture supplied into the combustion chamber 4 is uniformly dispersed throughout the combustion chamber 4. It constitutes a uniform combustion means 41 that performs combustion.

Furthermore, steps S1 to SI of the interrupt flow in FIG.
6 constitutes an acceleration operation detecting means 42 that detects the acceleration operation of the engine 1 based on the value of the acceleration flag T, and also includes step S6 of the control flow in FIG.
In response to the output of the accelerating operation detecting means 42, during accelerating operation in the stratified combustion region (low load region), the injection of stratified combustion fuel from the injection valve 12 of the combustion chamber 4 is substantially stopped and the air-fuel mixture is The control of the stratified combustion means 40 and the uniform combustion means 41 is corrected so that the stratified combustion of the air-fuel mixture is stopped and the uniform combustion twist #1 is injected from the injection valve 10 of the intake passage 5 to perform uniform combustion of the air-fuel mixture. This constitutes an acceleration control means 43.

Therefore, in the above embodiment, in the stratified combustion region (low load region) of the engine operating state, the fuel injection valve 12 for stratified combustion desired in the combustion chamber 4 is controlled by the stratified combustion means 40, The amount of fuel Qf from the fuel injection valve 12 of
The stratified combustion fuel I is directly injected and supplied to the combustion chamber 4 in the latter half of the compression stroke, and the opening degree of the throttle valve 9 is adjusted to approximately the full opening value TVl. Since the combustible air-fuel mixture is unevenly distributed only in the air-fuel mixture, the air-fuel ratio of the air-fuel mixture as a whole is significantly increased, and the stratified combustion of the air-fuel mixture is performed satisfactorily, thereby improving fuel efficiency.

Further, in the uniform combustion region (high load region) of the engine operating state, the operation of the fuel injection valve 10 for uniform combustion disposed in the intake passage 5 is controlled by the uniform combustion means 41. The uniform amount of fuel is adjusted according to the increase in load and is injected and supplied into the combustion chamber 4 in the first half of the intake stroke, and as a result, the uniform fuel is mixed evenly and dispersed throughout the combustion chamber 4. Since uniform combustion of air is performed, the output of the engine 1 increases as the load increases.

When acceleration operation is started in the stratified combustion region (low load 1ri), in this stratified combustion region, the injection of stratified combustion fuel from the injection valve 12 of the combustion chamber 4 is controlled by the acceleration control means 43. At the same time, the stratified combustion of the air-fuel mixture is effectively stopped, and instead of supplying fuel for stratified combustion,
Uniform combustion fuel is supplied from the injection valve 10 of the intake passage 5 to the combustion chamber 4.
Since uniform combustion of the air-fuel mixture is forcibly performed by the uniform combustion means 41, the engine output increases significantly even at the beginning of this accelerated operation. When the operating state shifts to a uniform combustion region (high load region) with this acceleration operation, uniform fuel injection from the fuel injection valve 10 on the intake passage 5 side is controlled by the uniform combustion means 41 as usual. Since uniform combustion of the air-fuel mixture continues, the engine output further increases and the vehicle accelerates well. Therefore, during acceleration operation from the stratified combustion region (low load region),
From the beginning of acceleration operation, the engine output can be increased through forced uniform combustion of the air-fuel mixture, thereby improving acceleration performance.

Moreover, at the beginning of acceleration operation (stratified combustion region), the intake passage 5
An increased amount of fuel is injected asynchronously from the fuel injection valve 10 on the side, and this fuel is supplied to the combustion chamber 4 when the intake valve 15 is opened, so responsiveness is increased and acceleration performance is further improved. I can do it.

In the above embodiment, the fuel supply means 13 is connected to the intake passage 5.
Although the fuel injection valve 10 for uniform combustion in the combustion chamber 4 and the fuel injection valve 11 for stratified combustion in the combustion chamber 4 are used, either one of them may be used. In that case, it is possible to achieve uniform combustion of the air-fuel mixture by advancing the fuel injection timing, and to perform stratified combustion of the air-fuel mixture by delaying the fuel injection timing.

(Effects of the Invention) As explained above, according to the present invention, during acceleration operation from a low load region where stratified combustion of the mixture is performed to a high load region where uniform combustion of the mixture is performed, even in the low load region, Since uniform combustion of the air-fuel mixture is performed forcibly and the engine output at the beginning of acceleration operation is significantly increased, acceleration response can be enhanced and acceleration performance can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention. Figures 2 to 8 show embodiments of the present invention, Figure 2 is an overall configuration diagram, Figures 3 to 5 are flowcharts showing the operation of the controller, and Figure 6 is a stratified combustion area and a uniform 7 is a diagram showing stratified fuel amount and uniform fuel resistance characteristics with respect to load, and FIG. 8 is a diagram showing target throttle valve opening characteristics with respect to output. DESCRIPTION OF SYMBOLS 1... Engine, 4... Combustion chamber, 10... Fuel injection valve for uniform combustion, 12... Fuel injection valve for stratified combustion, 13... Fuel supply means, 22... Fuel pump, 2
3... Injection pump, 28... Load sensor, 29...
- Rotation speed sensor, 34... Operating state detection means, 35.
...Controller, 40... Stratified combustion means, 41...
- Uniform combustion means, 42... detection means during accelerated operation, 43
...Acceleration control means.

Claims (1)

[Claims] (1) A fuel supply means for supplying fuel into the combustion chamber, an operating state detecting means for detecting the operating state of the engine, and receiving the output of the operating state detecting means, when the engine operating state is in a low load range, the combustion A stratified combustion means performs stratified combustion of the air-fuel mixture by controlling the fuel supply means so that the air-fuel mixture supplied into the room is stratified, and an output from the operating state detection means is received, and the engine operating state reaches a high load range. and a uniform combustion means for uniformly burning the air-fuel mixture by controlling the fuel supply means so that the air-fuel mixture supplied into the combustion chamber is uniform at certain times, and detecting when the engine is in acceleration operation. receiving the output of the detection means and the acceleration operation detection means;
Stratified combustion of an engine, characterized in that it is provided with an acceleration control means for correcting the control of the stratified combustion means and the uniform combustion means so that stratified combustion is stopped and uniform combustion is performed during acceleration operation in a low load range. Control device.