JPH09287525A - Combustion controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the accumulation of deposits to nozzle holes and the like of fuel injection means, and secure smooth fuel injection and the like, in a combustion controller for an internal combustion engine which can execute stratified burning. SOLUTION: Fuel injection valves 11 are arranged in the circumference of the inner wall surface of a cylinder head 4 in the vicinity of first intake valves 6a and second intake valves 6b of an engine 1, and fuel from the fuel injection valves 11 is ejected directly to the insides of air cylinders 1a. An electrical control unit (ECU) 30 controls an EGR rate (exhaust gas recirculating rate) fewer than before when judging that the cooling water temperature of the engine 1 is higher than a reference temperature, and also controls ignition timing on a phase delaying side than before. Thus, temperature of air-fuel mixture or a substantial combustion temperature is lowered, and a temperature in the vicinity of the fuel injection valves 11 is also lowered. Therefore, the accumulation of deposits to the nozzle holes and the like of the fuel injection valves 11, caused by abnormally excessively raising the temperature of the nozzle holes of the fuel injection valves 11, can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control apparatus for an internal combustion engine, and more particularly, to a combustion control apparatus for a direct injection type internal combustion engine.
The present invention relates to a combustion control device for an internal combustion engine capable of performing stratified combustion.

[0002]

2. Description of the Related Art Conventionally, as this type of technique, for example, one disclosed in Japanese Patent Application Laid-Open No. 6-81657 is known. In this technique, when the temperature of the fuel injection valve for in-cylinder injection (injector) is extremely low, the liquid fuel adhered around the nozzle of the injector is carbonized by combustion heat and gradually accumulated around the nozzle, In consideration of the empirical fact that the amount of the accumulated deposit causes clogging of the injection port, the temperature of the tip portion of the injector is set to be high to some extent.

That is, a part of the opening of the intake valve is covered by the mask wall, and the injector is arranged on the peripheral edge of the inner wall surface of the cylinder head opposite to the mask wall. Also, the tip of this injector is made to be retracted from the inner wall surface of the cylinder head.
With such a configuration, the temperature of the nozzle portion is prevented from lowering during intake, and the accumulation of deposits is suppressed.

[0004]

However, according to the experiments conducted by the present inventors, when the temperature of the engine becomes extremely high, the tip temperature of the injector also rises. In this case, the temperature rises and the deposit increases. It was clarified that the amount of deposits of P. That is, as shown in FIG. 11, when the tip temperature of the injector becomes high, such as when the engine is overheated,
It was confirmed that the amount of deposits accumulated on the injection port also increased, and as a result, the fuel flow rate decreased. Therefore, in such a case, smooth fuel injection may not be ensured and the combustion state of the engine may be hindered.

The present invention has been made to solve the above problems, and an object thereof is to provide a combustion control device for an internal combustion engine capable of stratified combustion even if the temperature of the internal combustion engine becomes high. A combustion control device for an internal combustion engine, which can suppress deposit accumulation on the injection port portion of the fuel injection device without complicating the device, and can ensure smooth fuel injection and a stable combustion state. To provide.

[0006]

In order to achieve the above object, in the invention described in claim 1, as shown in FIG. 1, fuel is injected into the cylinder of the internal combustion engine M1 to perform stratified charge combustion. Fuel injection means M2, operating state detection means M3 for detecting the operating state of the internal combustion engine M1 including at least the temperature of the internal combustion engine M1, and the operating state detection means M
Engine temperature determination means M4 for determining whether or not the temperature of the internal combustion engine M1 is higher than a predetermined temperature based on the detection result of 3.
And the internal combustion engine M1 by the engine temperature determination means M4.
The combustion control device for an internal combustion engine is provided with a combustion control means M5 for controlling the combustion of the internal combustion engine M1 in order to lower the substantial combustion temperature when it is determined that the temperature is higher than a predetermined temperature. .

However, the temperature detected by the operating condition detecting means M3 includes not only the case of directly detecting the temperature of the internal combustion engine M1 but also the case of indirectly detecting and estimating the temperature. is there.

According to a second aspect of the present invention, in the internal combustion engine combustion control device according to the first aspect, an exhaust gas recirculation passage communicating the exhaust passage and the intake passage of the internal combustion engine M1 with each other, Recirculation amount control means for controlling a recirculation amount of a part of exhaust gas discharged from the internal combustion engine M1 is recirculated to the intake air taken into the internal combustion engine through the exhaust gas recirculation passage, and the combustion control is provided. Means M
5 to the internal combustion engine M by the engine temperature determination means M4.
When it is determined that the temperature of 1 is higher than a predetermined temperature, the recirculation amount control unit controls the recirculation amount control unit to reduce the recirculation amount controlled by the recirculation amount control unit. That is the gist.

Further, in the invention described in claim 3, in the combustion control device for the internal combustion engine according to claim 1, ignition means for igniting the fuel gas supplied into the cylinder of the internal combustion engine M1 is provided. Together with the combustion control means M5
By the engine temperature determination means M4.
When it is determined that the temperature is higher than the predetermined temperature, the ignition timing retarding control means for controlling the ignition means to control the ignition timing by the ignition means to the retard side more than before is configured. The summary is.

(Operation) According to the invention described in claim 1, as shown in FIG. 1, the fuel is injected into the cylinder of the internal combustion engine M1 by the fuel injection means M2, and the fuel in the cylinder is burned. As a result, the internal combustion engine M1 obtains a driving force.

On the other hand, the operating state detecting means M3 detects the operating state of the internal combustion engine M1 including at least the temperature of the internal combustion engine M1. Further, the engine temperature determining means M4 determines whether or not the detected temperature is higher than a predetermined temperature. When the engine temperature determination means M4 determines that the temperature of the internal combustion engine M1 is higher than the predetermined temperature, the combustion control means M5 controls the combustion of the internal combustion engine M1 to lower the substantial combustion temperature.

Therefore, it is possible to prevent the temperature of the fuel injection means M2 from becoming abnormally high, and to suppress the accumulation of deposits on the injection portion. According to the invention described in claim 2, in addition to the function of the invention described in claim 1,
When the exhaust gas recirculation passage is opened by the recirculation amount control means, a part of the exhaust gas discharged from the internal combustion engine M1 is recirculated from the exhaust passage of the internal combustion engine M1 to the intake passage through the exhaust gas recirculation passage. And is recirculated to intake air taken into the internal combustion engine M1.

Further, in the present invention, the combustion control means M5 is
It is constituted by a recirculation amount auxiliary control means. Then, when the engine temperature determining means M4 determines that the temperature of the internal combustion engine M1 is higher than the predetermined temperature, the control means reduces the recirculation amount controlled by the recirculation amount control means. Then, the temperature of the fuel gas or the like (air mixture) introduced into the cylinder of the internal combustion engine M1 decreases, so that the temperature in the vicinity of the fuel injection means M2 decreases. Therefore, the above-described operation is achieved.

Further, according to the third aspect of the present invention,
In addition to the function of the invention described in claim 1, the fuel gas supplied into the cylinder of the internal combustion engine M1 is ignited by the ignition means, and the fuel in the cylinder explodes and burns.

In the present invention, the combustion control means M5 is constituted by ignition timing retard control means. When the engine temperature determining means M4 determines that the temperature of the internal combustion engine M1 is higher than a predetermined temperature, the ignition timing retard control means controls the ignition means, and the ignition timing by the ignition means changes. It is controlled on the retard side. Then, the combustion temperature is lowered, and the same operation as described above is achieved.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a combustion control device for an internal combustion engine according to the present invention will be described below in detail with reference to the drawings.

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

As shown in FIG. 3, the first intake port 7a
Is composed of a helical intake port, and the second intake port 7
b consists of a straight port that extends almost straight.
At the center of the inner wall surface of the cylinder head 4, an ignition plug 10 constituting ignition means is disposed. The ignition plug 10 is applied with a high voltage from an igniter 12 which also constitutes ignition means via a distributor not shown. The ignition timing of the ignition plug 10 is determined by the output timing of the high voltage from the igniter 12. Further, a fuel injection valve 1 as a fuel injection means is provided around the inner wall surface of the cylinder head 4 near the first intake valve 6a and the second intake valve 6b.
1 is arranged. That is, in the present embodiment, the fuel from the fuel injection valve 11 is directly injected into the cylinder 1a.

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

The surge tank 16 includes an intake duct 20
Is connected to the air cleaner 21 via the
Inside, a throttle valve 23 which is opened and closed by a step motor 22 is provided. That is, the throttle valve 23 of the present embodiment is of a so-called electronic control type.
The throttle valve 23 is controlled to open and close by being driven based on the output signal from the controller. By opening and closing the throttle valve 23, the amount of intake air introduced into the combustion chamber 5 through the intake duct 20 is adjusted. In the present embodiment, the intake duct 20, the surge tank 16, the first intake path 15a and the second intake path 15b
Thus, an intake passage is formed.

In the vicinity of the throttle valve 23, a throttle sensor 25 for detecting its opening (throttle opening TA) is provided. An exhaust manifold 14 is connected to the exhaust port 9 of each cylinder.
The exhaust gas after combustion is discharged to an exhaust duct (not shown) via the exhaust manifold 14.

Further, in the present embodiment, a known exhaust gas recirculation (EGR) mechanism 51 is provided. This E
The GR mechanism 51 includes an EGR passage 52 as an exhaust gas recirculation passage, and an EGR valve 53 provided in the middle of the EGR passage 52. The EGR passage 52 is provided so as to communicate between the intake duct 20 downstream of the throttle valve 23 and the exhaust duct. Also, the EGR valve 53
Has a built-in valve seat, valve body, and step motor (all not shown). The opening degree of the EGR valve 53 fluctuates when the stepping motor intermittently displaces the valve body with respect to the valve seat. When the EGR valve 53 is opened, a part of the exhaust gas discharged to the exhaust duct flows to the EGR passage 52. The exhaust gas flows to the intake duct 20 via the EGR valve 53. That is,
Part of the exhaust gas is recirculated into the intake air-fuel mixture by the EGR mechanism 51. At this time, the recirculation amount of the exhaust gas is adjusted by adjusting the opening degree of the EGR valve 53.

The above-described ECU 30 is a digital computer, and is connected to a RAM (random access memory) 3 via a bidirectional bus 31.
2, a ROM (Read Only Memory) 33, a CPU (Central Processing Unit) 34 composed of a microprocessor, an input port 35 and an output port 36. In the present embodiment, the ECU 30 constitutes engine temperature determination means, combustion control means, recirculation amount control means, recirculation amount auxiliary control means, and ignition timing retard control means.

An accelerator sensor 26A for generating an output voltage proportional to the amount of depression of the accelerator pedal 24 is connected to the accelerator pedal 24.
Accelerator opening ACCP is detected by 6A. The output voltage of the accelerator sensor 26A is input to the input port 35 via the AD converter 37. Similarly, the accelerator pedal 24 has a fully-closed switch 26B for detecting that the depression amount of the accelerator pedal 24 is "0".
Is provided. That is, the fully closed switch 26B
Generates a signal of "1" as the fully closed signal when the depression amount of the accelerator pedal 24 is "0", and generates a signal of "0" otherwise. And the fully closed switch 26
The output voltage of B is also input to the input port 35.

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

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

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

In addition, in the present embodiment, an intake pressure sensor 61 for detecting the pressure (intake pressure PiM) in the surge tank 16 is provided. Further, a water temperature sensor 62 that detects the temperature of the cooling water of the engine 1 (cooling water temperature THW) is provided. In the present embodiment, this water temperature sensor 62
The cooling water temperature THW detected by is adopted as the one corresponding to the temperature of the internal combustion engine (engine 1). The outputs of both sensors 61 and 62 are also output from the A / D converter 3
It is adapted to be input to the input port 35 via 7.

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

On the other hand, the output port 36 is connected to each of the fuel injection valves 11 and each of the step motors 1 via a corresponding drive circuit 38.
9, 22, the igniter 12 and the EGR valve 53 (step motor). Then, based on signals from the sensors 25 to 29, 61, and 62, the ECU 30 operates according to a control program stored in the ROM 33,
The fuel injection valve 11, the step motors 19 and 22, the igniter 12 (ignition plug 10), the EGR valve 53, etc. are suitably controlled.

Next, a program relating to various controls according to the present embodiment in the engine combustion control device having the above configuration will be described with reference to a flowchart. FIG. 4 shows the EGR valve 53 according to the present embodiment.
"Correction coefficient / correction term calculation routine" for executing combustion control by controlling the igniter 12 (spark plug 11) and the like
Is a flowchart showing the above, which is executed by the ECU 30 at an interrupt for each predetermined crank angle.

When the processing shifts to this routine, the ECU
First, at step 101, various sensors 25
From 29, 61, 62, a fully closed signal, accelerator opening AC
Various detection signals, such as CP, cooling water temperature THW, and engine speed NE, which indicate the current operating state are read.

Next, at step 102, based on the signal read this time, it is determined whether or not the fully closed switch 26B is currently off. If the fully closed switch 26B is off, it is determined that the idling state is not currently set, and the process proceeds to step 103.

In step 103, the accelerator opening ACCP read this time is set to a predetermined reference opening α
(For example, α = “50%”) is determined. Then, when the accelerator opening ACCP is lower than the reference opening α, the routine proceeds to step 104.

Further, in the following step 104,
It is determined whether the cooling water temperature THW read this time is higher than a predetermined reference water temperature β (eg β = “105 ° C.”). Then, when the cooling water temperature THW is higher than the reference water temperature β, it is determined that it is necessary to correct the EGR amount and the ignition timing, and the process proceeds to step 105.

In step 105, the EGR correction coefficient FEGR is calculated based on the cooling water temperature THW read this time. Here, when calculating the EGR correction coefficient FEGR, a map as shown in FIG. 5 is taken into consideration. That is, in the region where the cooling water temperature THW is equal to or lower than the reference water temperature β, the EGR correction coefficient FEGR is uniformly set to “1.0” as described later. On the other hand, the cooling water temperature TH
In a region where W is higher than the reference water temperature β, the EGR correction coefficient FEGR is set to a quadratic curve low value as the cooling water temperature THW increases (0 <FEGR <1).

Further, in the following step 106, the ignition timing correction term SAHot is calculated based on the cooling water temperature THW read this time. Here, this ignition timing correction term S
A map as shown in FIG. 6 is taken into consideration when calculating AHot. That is, in the region where the cooling water temperature THW is equal to or lower than the reference water temperature β, the ignition timing correction term SAHot is uniformly set to “0” as described later. In contrast,
In the region where the cooling water temperature THW is higher than the reference water temperature β, the ignition timing correction term SAHot is set to a larger retard side as the cooling water temperature THW increases. Then, after the above processing, the ECU 30 once ends the subsequent processing.

On the other hand, steps 102 to 10
When a negative determination is made in 4, the process proceeds to step 107. That is, when the fully closed switch 26B is turned on in step 102, the accelerator opening ACCP is equal to or larger than the reference opening α in step 103, or the cooling water temperature THW is equal to or smaller than the reference water temperature β in step 104. In this case, it is assumed that it is not necessary to correct the EGR opening degree and the ignition timing, and step 10
It moves to 7.

Then, in step 107, the ECU 30 sets the EGR correction coefficient FEGR to "1.0". Further, in the subsequent step 108, the ECU 30 sets the ignition timing correction term SAHot to "0". Then, the subsequent processing is temporarily terminated.

As described above, in the "correction coefficient / correction term calculation routine", the EGR correction coefficient FEGR and the ignition timing correction term SAHot are calculated according to the operating state at that time, particularly the cooling water temperature THW.

Next, based on the EGR correction coefficient FEGR and the ignition timing correction term SAHot set as described above, the target EGR opening EGR1 and the target ignition timing SA are actually determined, and EGR control and ignition timing are performed. The processing executed by the ECU 30 when performing the control will be described.
First, FIG. 7 shows the “target EG” executed by the ECU 30.
It is a flowchart which shows a R opening degree determination routine. This processing is also executed by interruption for each predetermined crank angle.

When the processing shifts to this routine, the ECU
First, in step 201, various sensors 2
From 5 to 29, 61 and 62, a fully closed signal, accelerator opening A
Various detection signals such as CCP, cooling water temperature THW, engine speed NE, etc., which indicate the current operating state, are read.

Next, at step 202, it is judged based on the signal read this time whether or not the fully closed switch 26B is currently off. If the fully closed switch 26B is off, in step 203, the basic EGR opening EGRBa is determined based on the engine speed NE and the accelerator opening ACCP that have been read this time.
Calculate se. Here, this basic EGR opening degree EGRB
A map such as that shown in FIG. 8 is taken into consideration when calculating the ase. That is, the basic EGR is changed according to the engine speed NE and the accelerator opening ACCP at that time.
The opening degree EGRBase is calculated by interpolation.

On the other hand, if the fully closed switch 26B is not turned off in step 202, it is determined that the accelerator pedal is not currently depressed and it is not necessary to perform the control of the present embodiment. ,
A predetermined opening γ (eg, γ = “10%”) is set as the basic EGR opening EGRBase.

Then, step 203 or step 20
4, the EG calculated in the "correction coefficient / correction term calculation routine" is added to the basic EGR opening degree EGRBase calculated this time in step 205.
The value obtained by multiplying the R correction coefficient FEGR is the final target EGR.
The opening degree EGR1 is set. Then, the subsequent processing is temporarily terminated.

As described above, in the "target EGR opening degree determination routine", the basic EGR opening degree EGRBase is calculated according to the operating state at that time, and the basic EGR opening degree EGRBase is calculated in the above routine. The target EGR opening degree EGR1 is determined by multiplying the EGR correction coefficient FEGR. Then, based on the target EGR opening degree EGR1, the EGR valve 53
Is controlled.

FIG. 10 is a flowchart showing a "target ignition timing determination routine" executed by the ECU 30. This processing is also executed by interruption for each predetermined crank angle.

When the processing shifts to this routine, the ECU
First, in step 301, various sensors 2
From 5 to 29, 61 and 62, a fully closed signal, accelerator opening A
Various detection signals such as CCP, cooling water temperature THW, engine speed NE, etc., which indicate the current operating state, are read.

Next, at step 302, it is judged based on the signal read this time whether or not the fully closed switch 26B is currently off. Then, when the fully closed switch 26B is off, in step 303, the basic ignition timing SABase is calculated based on the engine speed NE and the accelerator opening ACCP that are read this time.
Is calculated. Here, a map as shown in FIG. 9 is taken into consideration when calculating the basic ignition timing SABase. That is, the basic ignition timing SABas is changed according to the engine speed NE and the accelerator opening ACCP at each time.
e is interpolated.

On the other hand, in step 302, when the fully closed switch 26B is not off, it is determined that the accelerator pedal is not currently depressed and it is not necessary to perform the control of the present embodiment. ,
The predetermined ignition timing δ (for example, δ = “10 °”) is set to the basic ignition timing S.
Set as ABase.

Then, step 303 or step 30
4, the timing at which the ignition timing correction term SAHot calculated in the "correction coefficient / correction term calculation routine" is retarded from the basic ignition timing SABase calculated this time is finally determined in step 305. The target ignition timing SA is set, and the subsequent processing is temporarily terminated. Then, the subsequent processing is temporarily terminated.

As described above, in the "target ignition timing determination routine", the basic ignition timing SABase is calculated according to the operating state at that time, and the "correction coefficient / correction term calculation" is performed for the basic ignition timing SABase. The target ignition timing SA is determined by being retarded by the ignition timing correction term SAHot calculated in the "routine". Then, the igniter 12 (ignition plug 10) is controlled based on the target ignition timing SA.

Next, the function and effect of this embodiment will be described. (A) In the present embodiment, when the ECU 30 determines that the coolant temperature THW of the engine 1 is higher than the reference temperature β, the target EGR opening EGR1 is lower than the basic EGR opening EGRBase up to that point. Set to the value (E
GRBase * FEGR), and the EGR valve 53 is controlled based on the value. Therefore, the cylinder 1 of the engine 1
The temperature of the fuel gas or the like (air mixture) introduced into the inside a is lowered, the combustion temperature is substantially lowered, and the temperature in the vicinity of the fuel injection valve 11 is also lowered. Therefore, the fuel injection valve 11
It is possible to suppress the accumulation of deposits on the injection port portion and the like of the fuel injection valve 11 due to the temperature of the injection port portion of abnormally high. As a result, it is possible to ensure a smooth fuel injection and a stable combustion state.

(B) In the present embodiment, the ECU 3
When it is determined that the cooling water temperature THW is higher than the reference temperature β by 0, the basic ignition timing SA up to that point is further increased.
The timing retarded by the ignition timing correction term SAHot with respect to Base is set as the target ignition timing SA, and the igniter 12 is controlled based on the target ignition timing SA.
Therefore, the combustion temperature can be lowered, and the function and effect described in (a) above can be made more reliable.

(C) Further, in the present embodiment, the higher the cooling water temperature THW is than the reference temperature β, the more the EGR becomes.
The degree of consideration of the correction coefficient FEGR and the ignition timing correction term SAHot is increased. Therefore, the control corresponding to the temperature of the engine 1 (the temperature of the injection port of the fuel injection valve 11) at that time is executed. As a result, it is possible to minimize adverse effects on torque fluctuations and the like due to fluctuations in the EGR amount and ignition timing, and it is possible to perform control in accordance with actual conditions.

(D) In addition, in the present embodiment, by performing the above control, so-called overheating of the engine 1 can be suppressed. As a result, additional effects such as suppression of knocking and prevention of damage to the engine 1 can be expected.

The present invention is not limited to the above-described embodiment, but may be implemented as follows with a part of the configuration appropriately changed without departing from the spirit of the invention. (1) In the above embodiment, the water temperature sensor 62 is adopted as a means for detecting the temperature of the engine 1, and the cooling water temperature THW detected by the water temperature sensor 62 corresponds to the temperature of the internal combustion engine (engine 1). Considered as. On the other hand, by detecting or estimating other temperatures such as the wall surface temperature of the cylinder head, the exhaust gas temperature, the temperature in the fuel injection valve 11 and the like, it may be regarded as equivalent to the temperature of the engine 1.

(2) In each of the above embodiments, the present invention is embodied in the cylinder injection type engine 1, but any type of internal combustion engine of the type that performs so-called stratified charge combustion or weakly stratified charge combustion. It may be embodied in For example, a type in which the fuel is injected toward the back side of the head of the intake valves 6a and 6b of the intake ports 7a and 7b is also included. Although fuel injection valves are provided on the intake valves 6a and 6b side,
A type in which the fuel is injected directly into the cylinder bore (combustion chamber 5) is also included.

(3) Further, in the above-mentioned embodiment, the structure has the helical intake port and is capable of generating so-called swirl, but it is not always necessary to generate swirl. Therefore, for example, the swirl control valve 17, the step motor 19, and the like in the above embodiment can be omitted.

(4) Further, in the above embodiment, the present invention is embodied in the case of the gasoline engine 1, but it can be embodied in the case of a diesel engine or the like. (5) In the above embodiment, the EGR amount is controlled by controlling the opening / closing of the EGR valve 53.
By controlling the opening of the electronically controlled throttle valve 23, the suction amount of the exhaust gas recirculation gas can be controlled by the pressure difference due to the negative pressure.
A means for controlling the R amount may be used.

The technical idea which is not described in each claim of the claims and can be grasped from the above-mentioned embodiment will be described below together with its effect. (A) In the combustion control device for an internal combustion engine according to any one of claims 1 to 3, the higher the temperature of the internal combustion engine detected by the operating state detection means, the greater the degree of combustion control by the combustion control means. It is characterized by doing so.

With such a configuration, it is possible to minimize adverse effects on torque fluctuations and the like due to combustion fluctuations, and it is possible to perform control in accordance with actual conditions.

[0063]

As described in detail above, according to the present invention,
In a combustion control device for an internal combustion engine capable of stratified combustion, even if the temperature of the internal combustion engine becomes high, it is possible to suppress deposit accumulation on the injection port portion of the fuel injection means without causing complication of the device. Therefore, there is an excellent effect that a smooth fuel injection and a stable combustion state can be secured.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram showing a combustion control device for an engine in one embodiment.

FIG. 3 is an enlarged sectional view showing a cylinder portion of the engine.

FIG. 4 is a flowchart showing a “correction coefficient / correction term calculation routine” executed by the ECU.

FIG. 5 is a map showing a relationship between an EGR correction coefficient and a cooling water temperature.

FIG. 6 is a map showing the relationship between the cooling water temperature and the ignition timing correction term.

FIG. 7 is a flowchart showing a “target EGR opening degree determination routine” executed by the ECU.

FIG. 8 is a map showing a relationship between a basic EGR opening and an engine speed and an accelerator opening.

FIG. 9 is a map showing a relationship of basic ignition timing with respect to engine speed and accelerator opening.

FIG. 10 is a flowchart showing a “target ignition timing determination routine” executed by the ECU.

FIG. 11 is a graph showing the relationship of the fuel flow rate change rate with respect to the injector tip temperature.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as an internal combustion engine, 10 ... Spark plug which constitutes ignition means, 11 ... Fuel injection valve which constitutes fuel injection means, 12 ... Ignitator which constitutes ignition means, 25 ... Throttle sensor which constitutes operating state detection means, 26A: Accelerator sensor constituting operating state detecting means, 26B ... Fully closed switch constituting operating state detecting means, 27 ... Top dead center sensor constituting operating state detecting means, 28 ... Crank angle constituting operating state detecting means Sensor, 29 ... a swirl control valve sensor constituting an operating state detecting means,
30 ... An ECU that constitutes engine temperature determination means, combustion control means, recirculation amount control means, recirculation amount auxiliary control means, and ignition timing retard control means.

Claims (3)

[Claims] 1. A fuel injection means for injecting fuel into a cylinder of an internal combustion engine to perform stratified combustion, and an operating state detection means for detecting an operating state of the internal combustion engine including at least the temperature of the internal combustion engine, Based on the detection result of the operating state detection means, an engine temperature determination means for determining whether the temperature of the internal combustion engine is higher than a predetermined temperature, and the temperature of the internal combustion engine is higher than a predetermined temperature by the engine temperature determination means. And a combustion control means for controlling the combustion of the internal combustion engine so as to substantially lower the combustion temperature. 2. The combustion control device for an internal combustion engine according to claim 1, wherein an exhaust gas recirculation passage that connects an exhaust passage and an intake passage of the internal combustion engine, and a part of exhaust gas discharged from the internal combustion engine. Is provided with a recirculation amount control means for controlling the recirculation amount recirculated to the intake air taken into the internal combustion engine through the exhaust gas recirculation passage, and the combustion control means is provided for the internal combustion engine by the engine temperature determination means. When it is determined that the temperature of the engine is higher than a predetermined temperature, the recirculation amount auxiliary control means controls the recirculation amount control means to reduce the recirculation amount controlled by the recirculation amount control means. A combustion control device for an internal combustion engine, comprising: 3. The combustion control device for an internal combustion engine according to claim 1, wherein ignition means for igniting a fuel gas supplied into a cylinder of the internal combustion engine is provided, and the combustion control means is provided for the engine. When the temperature determining means determines that the temperature of the internal combustion engine is higher than a predetermined temperature, the ignition timing is retarded by controlling the ignition means to control the ignition timing by the ignition means to a retard side more than before. A combustion control device for an internal combustion engine, comprising a control means.