JP2001082210A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine to bring the combustion state of an internal combustion engine into a proper state, in a vehicle having an internal combustion engine the combustion state of which is switched. SOLUTION: A command to vary hysteresis of a switch condition used by a combustion state switching means 94 to switch the combustion state of a cylinder injection engine 10, based on output torque reduction operation of a cylinder injection engine 10 by a gear shifting torque reduction control means 92 or output torque control operation of the cylinder injection engine 10 by a first speed re-acceleration torque control means 106 is issued from a hysteresis width varying command means 108 to a hysteresis width varying means 110, and since hysteresis of a switching condition for a combustion condition by the hysteresis width varying means 110 is varied, a combustion state is rendered proper. Namely, despite of an output torque change demand to a cylinder injection engine 10 from a control device for a vehicle, the combustion state of the cylinder injection engine 10 is rendered proper and further, torque control demanded by a control device for a vehicle is excellently executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for controlling an internal combustion engine in a vehicle having an internal combustion engine whose combustion state can be switched and a control apparatus of the vehicle for generating a change in driving state. The present invention relates to a technique for suppressing a shock of a middle vehicle and stabilizing torque control of a control device of the vehicle.

[0002]

2. Description of the Related Art An in-cylinder injection engine in which gasoline is directly injected into a cylinder to perform lean combustion, and a mixture having a large air / fuel ratio (ie, air-fuel ratio = air / fuel) A / F is supplied to the engine. BACKGROUND ART There is known an internal combustion engine whose combustion state is switched, such as a lean burn engine that burns. In such an internal combustion engine in which the combustion state is switched, for example, homogeneous combustion (stoichiometric combustion) in which a mixture having a stoichiometric air-fuel ratio with an air-fuel ratio A / F of about 15 is burned, and the air-fuel ratio is smaller than the stoichiometric air-fuel ratio There is a property that torque fluctuation occurs between stratified combustion (lean combustion) that supplies an air-fuel mixture to the engine. For this reason, the shift between the homogeneous combustion and the stratified combustion is normally prohibited during the shift of the automatic transmission in which the torque reduction of the internal combustion engine is requested by the torque reduction control device during the shift, so that the shock during the shift is reduced. A control device that suppresses the increase has been proposed. For example, this is the control device described in Japanese Patent Application Laid-Open No. 8-193535.

[0003]

In the conventional control device as described above, the switching of the combustion state of the internal combustion engine itself is prohibited during the shifting of the automatic transmission. When the operating state, for example, the engine speed or the engine load changes, there is a disadvantage that the combustion itself of the internal combustion engine becomes inappropriate because the combustion state does not match the operating state. As described above, if the combustion of the internal combustion engine becomes inappropriate, the shift shock may be increased, and the torque control by the torque down control device during shifting may not be performed properly. Such inconveniences are caused not only by the torque down control device during shifting, but also by a change in the vehicle driving state such as the first speed re-acceleration torque control, TRC control, VSC control, and torque converter lock-up clutch control. A control device also exists.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle having an internal combustion engine whose combustion state can be switched, in which the combustion state of the internal combustion engine is made appropriate. It is to provide a control device.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the gist of the present invention is to provide a control device for an internal combustion engine whose combustion state can be switched, which has (a) a hysteresis. Combustion state switching means for switching the combustion state of the internal combustion engine according to a switching condition; (b) hysteresis width changing means for changing the hysteresis width; and (c) operation of a vehicle control device for generating a change in driving state. And a hysteresis width change instructing means for instructing the hysteresis changing means to change the hysteresis width.

[0006]

In this manner, the hysteresis of the switching condition used by the combustion state switching means for switching the combustion state of the internal combustion engine is changed on the basis of the operation of the control device of the vehicle which causes the change of the driving state. Is issued from the hysteresis width change instructing means to the hysteresis width changing means, and the hysteresis width is changed by the hysteresis width changing means, so that the combustion state becomes appropriate. That is, irrespective of the output torque change request from the control device of the vehicle to the internal combustion engine, the combustion state of the internal combustion engine becomes appropriate, and the torque control requested from the control device of the vehicle becomes successful. Furthermore, frequent switching of the combustion state is eliminated, and the combustion state becomes appropriate.

By the way, apart from the above-mentioned prior art, if the switching of the combustion state of the internal combustion engine is simply permitted during a shift or the like, frequent switching of the combustion state, that is, hunting occurs, and the combustion state is switched. In some cases, the engine torque fluctuation and torque control cannot be satisfactorily performed, and the shift shock may increase.

[0008]

In another preferred embodiment of the present invention, the control device for the vehicle for causing the change in the driving state preferably includes a shift for temporarily reducing the output torque of the internal combustion engine during a shift period of the automatic transmission. Medium torque reduction control device, first during coasting
A first-speed re-acceleration torque control device that performs torque control of the internal combustion engine to reduce shock when the one-way clutch is engaged due to an increase in engine rotation speed during a re-acceleration operation after shifting to a high-speed state; TRC control (traction control) device that lowers the output torque of the internal combustion engine to increase the driving force of the wheels, that is, traction (traction force) when the vehicle starts on a low μ road with low frictional resistance, and oversteer or understeer during vehicle turning. A VSC control device for temporarily controlling the output torque of the internal combustion engine to suppress the pressure, or a lock-up clutch for temporarily reducing the output torque of the internal combustion engine when a lock-up clutch provided in the fluid coupling is engaged This is an opening / closing torque control device. Each of the above-described torque-down control device during shifting, the first-speed re-acceleration torque control device, the TRC control device, the VSC control device, and the lock-up clutch opening / closing torque control device changes the output torque of the internal combustion engine, that is, changes the driving state of the drive system. Change, so that regardless of the output torque change request from the control devices to the internal combustion engine,
The combustion state of the internal combustion engine becomes appropriate, and the torque control required by the control device of the vehicle is successfully performed.

Preferably, the hysteresis width change instructing means instructs the hysteresis changing means to change the hysteresis width so as to enlarge the hysteresis width.
With this configuration, the hysteresis width of the switching condition used by the combustion state switching means for switching the combustion state of the internal combustion engine based on the request from the control device of the vehicle, that is, the output torque change request for the internal combustion engine, is expanded. Therefore, frequent switching (switching hunting) of the combustion state of the internal combustion engine during the output torque change request to the internal combustion engine is prevented, and a shift shock and a shock at the first speed re-acceleration are suitably mitigated. That is, frequent switching is suppressed, the combustion state of the internal combustion engine becomes appropriate, and the torque control requested by the vehicle control device is favorably performed.

Preferably, the internal combustion engine is a direct injection engine in which gasoline is directly injected into a cylinder to perform lean combustion, and a switching condition used by combustion state switching means for switching a combustion state of the internal combustion engine. Are two-dimensional coordinates of a rotational speed axis representing the rotational speed of the in-cylinder injection engine and a load axis representing the load of the in-cylinder injection engine. Between the homogeneous → stratified switching line and the stratified → homogeneous switching line provided outside thereof, and the hysteresis width of the switching condition is between the homogeneous → stratified switching line and the stratified → homogeneous switching line. The hysteresis width change instructing means instructs to change the homogenous to stratification switching line to the rotation speed decreasing side. With this configuration, the hysteresis in the rotational direction of the switching condition is expanded only when there is a request from the control device of the vehicle, that is, the output torque change request for the internal combustion engine. There are advantages to be done. Further, if the rotation change of the direct injection engine is accompanied by a torque change in accordance with a request from the control device of the vehicle, that is, a request for a change in output torque to the direct injection engine, frequent switching (switching hunting) of the combustion state is performed. Preferably prevented.

[0011]

According to a second aspect of the present invention, there is provided a control apparatus for an internal combustion engine capable of switching a combustion state, comprising: (a) hysteresis; A switching condition storage means for storing in advance a switching condition whose hysteresis width is determined according to the type of the power transmission device of the vehicle; and (b) the switching condition storage means. Combustion state switching means for switching the combustion state of the internal combustion engine according to a switching condition having hysteresis.

[0012]

With this configuration, the combustion state of the internal combustion engine is switched by the combustion state switching means in accordance with the switching condition in which the width of the hysteresis is determined according to the type of the driving device of the vehicle. Thus, a combustion state suitable for the type of the power transmission device of the vehicle can be obtained. For example,
When the power transmission device of the vehicle is a transmission that changes the transmission ratio, the hunting of the rotational speed of the manual transmission is smaller than that of the automatic transmission. The width of the hysteresis is reduced as compared with the case where the machine is used.

[0013]

Preferably, the internal combustion engine is a direct injection engine in which gasoline is directly injected into a cylinder to perform lean combustion, and a combustion state for switching a combustion state of the internal combustion engine. The switching condition used by the switching means is a region in which stratified combustion of the direct injection engine is performed in two-dimensional coordinates of a rotation speed axis representing the rotational speed of the direct injection engine and a load axis representing the load of the direct injection engine. And a homogeneous-to-stratified switching line and a stratified-to-homogeneous switching line provided outside the homogeneous-to-stratified switching line, and the hysteresis width of the switching condition is the homogeneous-to-stratified switching line. → corresponds to the interval between the homogeneous switching line, the vehicle drive device is a transmission interposed in the vehicle power transmission path, the width of the hysteresis, the vehicle drive device hand If a transmission is compared in the case of automatic transmission, in which said modified to become smaller in a direction to expand the region of stratified combustion of the internal combustion engine. That is, the width of the hysteresis is changed so as to increase in the direction in which the stratified combustion region of the internal combustion engine is reduced when the driving device of the vehicle is an automatic transmission, as compared with the case where the driving device is a manual transmission. It was done. In this way, the stratified combustion region is made as large as possible.

[0014]

According to a third aspect of the present invention, there is provided a control apparatus for an internal combustion engine capable of switching a combustion state. Combustion state switching means for switching the combustion state of the internal combustion engine;
(b) the combustion state of the internal combustion engine is preferentially switched from lean combustion to predetermined combustion with a higher mixture ratio than that based on a request from a control device of the vehicle that causes a change in the driving state. And priority switching instruction means for instructing the combustion state switching means.

[0015]

According to the third aspect of the present invention, the combustion state of the internal combustion engine is changed from lean combustion to higher than that of lean combustion based on a request from the control device of the vehicle which causes a change in the driving state by the priority switching command means. When the combustion state switching means is instructed to preferentially switch to the predetermined combustion in which the mixture ratio is set high, the combustion state of the internal combustion engine is preferentially switched to the predetermined combustion by the combustion state switching means. Therefore, the combustion state of the internal combustion engine becomes appropriate irrespective of the output torque change request from the control device of the vehicle to the internal combustion engine, and the torque control requested by the control device of the vehicle goes well. For example, since the method of controlling the output torque of the internal combustion engine differs for each combustion state of the internal combustion engine, the output torque of the internal combustion engine can be controlled using the same method.

[0016]

Preferably, the internal combustion engine is an in-cylinder injection engine for directly injecting gasoline into a cylinder to perform lean combustion, and the priority switching command means includes: The switching condition used by the combustion state switching means for switching the state changes the combustion state of the in-cylinder injection engine from stratified combustion or weak stratified combustion to stoichiometric air based on a request from a control device of the vehicle that causes a change in the driving state. The combustion state switching means is instructed to preferentially switch to homogeneous combustion (stoichiometric combustion) in which the fuel is burned near the fuel ratio. In this case, homogeneous combustion is preferentially performed. Therefore, by retarding the ignition timing or changing the intake air amount based on a request from the control device of the vehicle, the output of the direct injection engine can be preferably adjusted. The torque is controlled.

[0017]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a skeleton view illustrating the structure of a vehicle power transmission device to which the present invention is applied. In FIG. 1, a direct injection engine 10 is a four-stroke internal combustion engine in which a combustion state is switched. Lean combustion, ie, stratified combustion, in which an air-fuel ratio is larger than a stoichiometric air-fuel ratio by directly injecting gasoline into a cylinder. Is realized. The output of the in-cylinder injection engine 10 is
2 is transmitted to the automatic transmission 14 and transmitted to drive wheels via a differential gear device and an axle (not shown).

The torque converter 12 is used for the engine 1
Pump wheel 18 connected to the crankshaft 16 and the turbine wheel 2 connected to the input shaft 20 of the automatic transmission 14.
2, a direct connection clutch or lock-up clutch 24 for directly connecting between the pump wheel 18 and the turbine wheel 22 and a stator 28 whose rotation in one direction is prevented by a one-way clutch 26. .

The automatic transmission 14 includes a first transmission 30 for switching between high and low gears, and a second transmission 32 for switching between a reverse gear and four forward gears. The first transmission 30 includes an HL planetary gear unit 34 including a planetary gear P0 rotatably supported by the sun gear S0, the ring gear R0, and the carrier K0 and meshed with the sun gear S0 and the ring gear R0; The clutch C0 and the one-way clutch F0 are provided between the sun gear S0 and the housing 41, and the brake B0 is provided between the sun gear S0 and the housing 41.

The second transmission 32 is a first planetary gear train 3 comprising a sun gear S1, a ring gear R1, and a planet gear P1 rotatably supported by the carrier K1 and meshed with the sun gear S1 and the ring gear R1.
6, a second planetary gear set 38 including a sun gear S2, a ring gear R2, and a planetary gear P2 rotatably supported by the carrier K2 and meshed with the sun gear S2 and the ring gear R2; a sun gear S3, a ring gear R3; And a third planetary gear unit 40 including a planetary gear P3 rotatably supported by the carrier K3 and meshed with the sun gear S3 and the ring gear R3.

The sun gear S1 and the sun gear S2 are integrally connected to each other, the ring gear R1, the carrier K2, and the carrier K3 are integrally connected, and the carrier K3 is connected to the output shaft 42. Further, a ring gear R2 is integrally connected to the sun gear S3. A clutch C1 is provided between the ring gear R2 and the sun gear S3 and the intermediate shaft 44, and the sun gear S1 and the sun gear S3 are provided.
A clutch C2 is provided between the clutch shaft 2 and the intermediate shaft 44. A band-type brake B1 for stopping rotation of the sun gear S1 and the sun gear S2 is provided on the housing 41.
It is provided in. A one-way clutch F1 is provided between the housing 41 and the sun gear S1 and the sun gear S2.
And a brake B2 are provided in series. The one-way clutch F1 is configured to be engaged when the sun gear S1 and the sun gear S2 try to reversely rotate in the direction opposite to the input shaft 20.

A brake B3 is provided between the carrier K1 and the housing 41, and a brake B4 and a one-way clutch F2 are provided between the ring gear R3 and the housing 41 in parallel. This one-way clutch F
2 is configured to be engaged when the ring gear R3 attempts to rotate in the reverse direction.

Such an automatic transmission 14 is, for example, shown in FIG.
Are switched to one of the first reverse gear and the fifth forward gear in which the speed ratio is sequentially different. FIG.
In the figures, a circle indicates an engaged state, a blank indicates a released state, and a black indicates an engaged state when an engine brake is generated. For example, when the shift lever 72 (see FIG. 3) is in the “D” range, the vehicle speed V is reduced by a brake operation for turning, for example, and the vehicle is shifted down from the third speed to the first speed, for example. ,
When the engine speed _NE is increased by performing a re-acceleration operation near the end of the turn, the one-way clutch F
By the engagement of the second gear, the first gear is achieved, and the power is transmitted again.

The in-cylinder injection engine 10 includes, for example,
A pair of intake ports connected to a pair of intake holes opened and closed by an unillustrated intake valve; a pair of exhaust ports connected to a pair of exhaust holes opened and closed by an unillustrated exhaust valve; A switching valve provided at one of the pair of intake ports and opened and closed to change the airflow flowing into the cylinder, and a valve actuator for driving the switching valve to open and close are provided for each cylinder. By changing the fuel injection amount into the cylinder, the fuel injection timing, and the operation of the switching valve thereof, for example, as shown in FIG.
The combustion state is switched. In FIG. 4, the air-fuel ratio A / F is a ratio (= air / fuel) of the air-fuel of the air-fuel mixture to be taken into the in-cylinder injection engine 10.
It is varied between 15 (during homogeneous combustion) and 50 (during stratified combustion). At the time of homogeneous combustion, the air-fuel ratio is set to a stoichiometric air-fuel ratio, for example, 15 (air: fuel = 15: 1), and fuel is injected in the intake process. At the time of lean combustion, the air-fuel ratio is set to a value larger than 15. During stratified charge combustion, the air-fuel ratio is set to a stoichiometric air-fuel ratio, for example, 50 (air: fuel = 55: 1), and fuel injection is performed in the compression step. Further, at the time of weak stratified combustion, the air-fuel ratio is made smaller than at the time of stratified combustion, and fuel injection is performed in the intake process and the compression process. Lean combustion refers to a case in which the air-fuel ratio is higher than the stoichiometric air-fuel ratio, for example, the above-described stratified combustion and weakly stratified combustion. In some cases, the lean combustion or the weak stratified combustion is not provided.

FIG. 3 is a diagram for explaining the control device of the vehicle. An operation amount A _CC (%) of the accelerator pedal 50 is detected by an accelerator operation amount sensor 51. The accelerator pedal 50 is largely depressed according to the driver's required output, and corresponds to an acceleration operation member. An opening angle (opening degree) θ _TH (%) basically corresponding to the operation amount A _CC of the accelerator pedal 50 is provided to the intake pipe of the in-cylinder injection engine 10 by the throttle actuator 54.
A throttle valve 56 is provided. The in-cylinder injection engine 10 is provided in the bypass passage 52 for bypassing the throttle valve 56 for idling rotation control.
An ISC valve 53 for controlling the intake air amount when the throttle valve 56 is fully closed is provided in order to control the idle rotation of the engine.
Inhalation for detecting an intake air quantity sensor 60, the temperature TA of intake air for detecting an intake air quantity Q of the engine rotational speed sensor 58, the engine 10 for detecting the rotational speed N _E of the engine 10 (rpm) Air temperature sensor 6
2. The fully closed state of the throttle valve 56 and its opening degree θ
_A throttle sensor 64 with an idle switch for detecting _TH , a vehicle speed sensor 66 for detecting a rotational speed NOUT (rpm) of the output shaft 42, that is, a vehicle speed V, and a coolant temperature TW of the in-cylinder injection engine 10. A coolant temperature sensor 68, a brake switch 70 for detecting operation of a brake, an operation position sensor 74 for detecting an operation position PSH of a shift lever 72, a rotation speed NIN of the input shaft 20, that is, a rotation speed NC0 of the clutch C0 (= Input shaft rotation sensor 7 for detecting turbine rotation speed NT)
3, such as an oil temperature sensor 75 for detecting the working oil temperature TOIL of the hydraulic control circuit 84 is provided, from the sensors, the engine rotational speed N _E, intake air quantity Q, intake air temperature TA, the throttle valve The signals representing the opening degree θ _TH , the vehicle speed V, the engine coolant temperature TW, the brake operating state BK, the operating position PSH of the shift lever 72, the input shaft rotation speed NC0, and the operating oil temperature TOIL are transmitted to the electronic control unit 76 for the engine or for shifting. It is supplied to the electronic control unit 78.

The engine electronic control unit 76 shown in FIG.
A so-called microcomputer having a PU, a RAM, a ROM, and an input / output interface.
The input signal is processed in accordance with a program stored in the ROM in advance while utilizing the temporary storage function of, and various engine controls are executed. For example, the fuel injection valve 79 is controlled for controlling the fuel injection amount, and the igniter 8 is controlled for controlling the ignition timing.
0 to control the ISC valve 5 for idle speed control.
3 and a throttle valve 56 is controlled by a throttle actuator 54 for traction control. In controlling the throttle valve 56, the engine electronic control unit 76 drives the throttle actuator 54 based on the actual accelerator pedal operation amount A _CC from a relationship (not shown), and basically, the accelerator pedal operation amount A _CC increases. Accordingly, the throttle valve opening θ _TH is increased. Further, the engine electronic control unit 76 executes the torque reduction control during shifting, and temporarily reduces the output of the engine 10 during the shifting period of the automatic transmission 14 in order to reduce the shifting shock. The engine electronic control unit 76
Executes the first speed re-acceleration torque control, and controls the throttle valve 56 and the engine output so that the engagement shock of the one-way clutch F2 is reduced during the first speed re-acceleration. Further, engine electronic control unit 76 determines the combustion state based on the actual engine rotational speed _NE and the load of in-cylinder injection engine 10 from the relationship stored in advance shown in FIG. The combustion state is switched by controlling the fuel injection amount, the fuel injection timing, and the like so that the combustion state is obtained. In-cylinder injection engine 10
Is an actual load amount or a load ratio determined based on, for example, the throttle valve opening θ _TH or the accelerator pedal operation amount _ACC .

The engine electronic control unit 76 is communicably connected to the speed change electronic control unit 78 so that signals necessary for one of them are appropriately transmitted from the other. The electronic control unit 78 for shifting is also a microcomputer similar to that described above. The CPU processes input signals in accordance with a program stored in the ROM in advance while utilizing the temporary storage function of the RAM. The valves SL1, SL2, SL3, SL4 or the linear solenoid valves SLU, SLT, SLN are driven. Specifically, for example, the gear position of the automatic transmission 14 is determined based on the actual throttle valve opening θ _TH and the vehicle speed V from a previously stored shift diagram shown in FIG. 6, and the determined gear position is determined. The solenoid valves SL1, SL2,
Drive SL3 and SL4. The solid line in FIG. 6 is an upshift line, and the broken line is a downshift line. The shift electronic control device 78 outputs a request to temporarily reduce the engine output during the shift period in order to reduce a shift shock generated when the automatic transmission 14 shifts.

FIG. 7 shows the electronic control unit 76 for the engine.
FIG. 3 is a functional block diagram illustrating a main part of a control function of a shift electronic control device 78. 7, the shift control means 90 determines the gear position of the automatic transmission 14 based on the actual throttle valve opening θ _TH and the vehicle speed V from, for example, a previously stored shift diagram shown in FIG. The solenoid valves SL1, SL2, SL
3. Control SL4. Shifting torque reduction control means 92
Temporarily reduces the output torque of the in-cylinder injection engine 10 during the shift period of the automatic transmission 14 in order to suppress a shift shock.

The combustion state switching means 94, for example on the basis of the actual load is determined based on the actual engine rotational speed N _E and the accelerator operation amount A _CC from pre-stored switching condition shown in FIG. 5, the cylinders The combustion state of the internal injection engine 10 is switched. Switching condition shown in Figure 5, in an orthogonal two-dimensional coordinate composed of the load shaft 98 Metropolitan representing the load of the rotational speed shaft 96 and the direct injection engine 10 representing the rotational speed N _E of the direct injection engine 10, the cylinder injection It is represented by a homogeneous to stratified switching line 100 (solid line) and a stratified to homogenous switching line 102 (broken line) provided outside the region where the engine 10 performs stratified combustion and the region where the homogeneous combustion is performed. A hysteresis for switching determination is provided between the homogeneous → stratified switching line 100 and the stratified → homogeneous switching line 102. The hysteresis width of the switching condition corresponds to the interval between the homogeneous → stratified switching line 100 and the stratified → homogeneous switching line 102.

The first speed re-acceleration torque control means 106 is down-shifted, for example, from the third gear to the first gear by the shift control means 90 when the vehicle speed V decreases due to the deceleration or braking operation of the vehicle. When the vehicle is running and the re-acceleration operation is performed by the accelerator pedal 50 in an unengaged state in which the one-way clutch F2 for achieving the first gear is still slipping, the one-way clutch F2 is engaged. to mitigate the shock, for example, as shown in FIG. 9, a throttle to drive the throttle valve 56 as in the vicinity of the rotational engine speed N _E and the raised quickly synchronize to suppress relaxed allowed or output torque that increases simultaneously controlling the actuator 54, in the vicinity of time point t ₁ near i.e. the synchronous speed running retarding the ignition timing,
The output torque of the direct injection engine 10 during re-acceleration is adjusted. The two-dot chain line in FIG. 9 indicates the virtual throttle valve opening corresponding to the load during stratified combustion, for example. The shifting torque reduction control means 92 and the first speed re-acceleration torque control means 106 are a part of the control function of the engine electronic control unit 76, and the engine in a state where some of the functions are generated. The electronic control unit 76 corresponds to a torque reduction control device during shifting or a first speed re-acceleration torque control device.

The hysteresis width change instructing means 108 is based on the operation of the above-mentioned in-shift torque reduction control means 92 or the first speed re-acceleration torque control means 106 corresponding to the control device of the vehicle for generating the change of the driving state, that is, On the basis of the request from the during-shift torque reduction control means 92 or the first-speed re-acceleration torque control means 106, a change command is issued to the hysteresis changing means 110. The hysteresis changing means 110 responds to the command from the hysteresis width changing command means 108, for example, by shifting a part of the uniform-to-stratification switching line 100 of the switching condition shown in FIG. Increase the width of the hysteresis in the speed direction. The alternate long and short dash line in FIG. 5 shows this state.

FIG. 8 shows the electronic control unit 76 for the engine.
It is a flowchart for explaining the main part of the control operation of,
9 shows a hysteresis change control routine. 8, at SA1 corresponding to the hysteresis width change instructing means 108, the torque reduction control during gear shifting performed by the torque reduction control means 92 during gear shifting is executed, or the torque is reduced by the first speed reacceleration torque control means 106. It is determined whether the first speed re-acceleration torque control is being executed. If the determination in SA1 is denied, the process proceeds to SA4 in FIG.
The normal combustion state switching conditions shown by the solid line and the broken line are used for the switching judgment of the combustion state switching means 94.

However, if the determination in SA1 is affirmative, the process proceeds to S corresponding to the hysteresis width changing means 110.
In A2, the homogeneous to stratification switching line 10 shown by the solid line in FIG.
The hysteresis width in the engine rotational speed direction is expanded by shifting a part of 0 to the low engine rotational speed side as shown by the one-dot chain line. Next, in SA3, SA1
It is determined whether the torque reduction control or the first speed re-acceleration torque control during the shift determined to be under control is completed. Initially, the determination at SA3 is denied, so that SA2 and subsequent steps are repeatedly executed.

If the determination at SA3 is affirmative during the repetition of SA2 and subsequent steps, the control proceeds to SA4 from the homogeneous to stratified switching line 100 shown by the solid line in FIG. Is returned to the normal combustion state switching condition.

As described above, according to the present embodiment, the operation of the control device of the vehicle for generating the change of the driving state, that is, the operation of reducing the output torque of the direct injection engine 10 by the torque reduction control means 92 during shifting, or A command for changing the hysteresis of the switching condition used by the combustion state switching means 94 for switching the combustion state of the direct injection engine 10 based on the output torque control operation of the direct injection engine 10 by the first speed re-acceleration torque control means 106. Is commanded from the hysteresis width changing command means 108 (SA1) to the hysteresis width changing means 110 (SA2), and the hysteresis width changing means 110 (SA2) changes the hysteresis width of the switching condition of FIG. Is appropriate. That is, irrespective of the output torque change request from the control device of the vehicle to the direct injection engine 10, the combustion state of the direct injection engine 10 becomes appropriate, and the torque control requested by the control device of the vehicle goes well. become.

According to the present embodiment, the hysteresis width change instructing means 108 (SA1) instructs the hysteresis changing means 110 to change the hysteresis width so as to increase the hysteresis width. The hysteresis width of the switching condition used by the combustion state switching means 94 for switching the combustion state of the in-cylinder injection engine 10 is expanded based on a request from the device, that is, a request to change the output torque of the in-cylinder injection engine 10. Frequent switching (switching hunting) of the combustion state of the in-cylinder injection engine 10 during a request to change the output torque to the in-cylinder injection engine 10 is prevented, and a shift shock and a shock at the first speed re-acceleration are suitably mitigated. That is, the frequent switching is suppressed, the combustion state of the direct injection engine 10 becomes appropriate, and the torque control requested by the control device of the vehicle is favorably performed.

Further, according to this embodiment, the hysteresis width change command means 108 (SA1) is to change its homogeneous → stratified switching line 100 to the decreasing side of the engine speed N _E at the switching condition shown in FIG. 5 Therefore, the hysteresis in the rotation direction of the switching condition is expanded only when there is a request from the control device of the vehicle, that is, only when there is a request to change the output torque to the in-cylinder injection engine 10. Combustion takes place as much as possible,
There is an advantage that fuel efficiency is improved. Further, the direct injection engine 1 is controlled by a torque change in accordance with a request from the control device of the vehicle, that is, a request to change the output torque of the direct injection engine 10.
In the case where the rotation fluctuation is accompanied by 0, frequent switching (switching hunting) of the combustion state is suitably prevented.

Incidentally, the first speed re-acceleration torque control means 10
When the first condition re-acceleration torque control is executed, the hysteresis in the rotational direction of the above switching condition is not expanded, and when the operation is switched to the stratified operation region, the ignition timing is retarded effectively as shown in FIG. As shown by the broken line in FIG. 9, the one-way clutch F that establishes the first gear stage does not operate.
The engagement of 2 causes a large shock.

Next, another embodiment of the present invention will be described. In the following description, the same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 10 shows another embodiment of the present invention.
FIG. 7 is a diagram showing switching conditions used by combustion state switching means 94. The switching condition of this embodiment is the same as in FIG. 5 _except that the rotation speed axis 96 representing the rotation speed NE of the direct injection engine 10 is used.
And the load axis 98 representing the load of the in-cylinder injection engine 10 in orthogonal two-dimensional coordinates.
A uniform-to-stratified switching line 114 (solid line) provided between the region where the stratified combustion of 0 is performed and the region where homogeneous combustion is performed, and a stratified-to-homogeneous switching line 116 (dashed line) provided outside thereof. In addition, a hysteresis for switching determination is provided between the homogeneous → stratified switching line 114 and the stratified → homogeneous switching line 116. Further, the hysteresis width corresponds to the interval between the homogeneous → stratified switching line 114 and the stratified → homogeneous switching line 116. The homogenous-to-stratification switching line 114 (solid line) of this embodiment is shifted to a lower rotational speed side, that is, to a side that reduces the stratification combustion region, as compared with the manual transmission homogenous-to-stratification switching line 118 shown by a dashed line. The hysteresis width is set to be large.

Generally, a manual transmission has a relatively low possibility of hunting in the rotational direction, while an automatic transmission 14 has a relatively high possibility of hunting in the rotational direction. For this reason, according to the present embodiment, the appropriate hysteresis is expanded according to the power transmission device (automatic transmission 14) provided in the vehicle, so that the switching of the combustion state of the direct injection engine 10 frequently occurs. Instead, an appropriate combustion state is obtained and the combustion state is stabilized. Further, in the present embodiment, the homogenous → stratification switching line 1 is configured such that a part of the homogenization → stratification switching line 118 (dashed line) for the manual transmission is shifted to the rotation speed decreasing side.
Since the hysteresis width is expanded by setting 14 (solid line), stratified combustion is performed as much as possible, and there is an advantage that fuel efficiency is improved.

FIG. 11 shows an engine electronic control unit 76 and a shift electronic control unit 7 according to another embodiment of the present invention.
8 is a functional block diagram for explaining a main part of the control function of FIG. 11 differs from the embodiment of FIG. 7 in that the priority switching command means 122 is provided in place of the hysteresis width changing command means 108 and the hysteresis width changing means 110. The priority switching command means 122 is based on the operation of a control device of the vehicle that generates a change in the driving state of the vehicle, for example, the torque reduction control 92 during shifting, and the torque reduction during shifting, that is, the torque reduction during shifting. Based on a request from the control 92 and the first-speed re-acceleration torque control means 106, the combustion state of the in-cylinder injection engine 10 is changed from lean combustion such as stratified combustion or weak stratified combustion to a predetermined mixture ratio higher than that of lean combustion. Combustion state switching means 9 for preferentially switching to combustion, for example, homogeneous combustion.
Command 4

FIG. 12 shows the electronic control unit 7 for the engine.
6 is a flowchart for explaining a main part of the control operation of No. 6, which shows a combustion state priority switching control routine. FIG.
In S2, S corresponding to the priority switching command means 122
In B1, it is determined whether the torque reduction control during gear shifting performed by the torque reduction control means 92 during gear shifting is being performed, or the first speed re-acceleration torque control being performed by the first speed re-acceleration torque control means 106 is being performed. Is determined. This SB
If the determination of 1 is denied, in SB4, normal combustion state switching control using, for example, normal combustion state switching conditions shown by the solid line and the broken line in FIG. 5 is executed.

However, if the determination at SB1 is affirmative, the combustion state of the in-cylinder injection engine 10 is preferentially set to homogeneous combustion (stoichiometric combustion) at SB2 corresponding to the combustion state switching means 94. Next, at SB3, it is determined whether the torque reduction control or the first-speed re-acceleration torque control during the shift determined to be under control at SB1 has been completed. Initially, the determination at SB3 is denied, so that the steps from SB2 onward are repeatedly executed. That S
If the determination at SB3 is affirmative during the repetitive execution of B2 and the subsequent steps, at SB4, for example, a normal → stratified switching line 100 shown by a solid line in FIG. The control is returned to the combustion state switching control using the switching condition.

According to this embodiment, the priority switching command means 12
2 (SB1), the combustion state of the in-cylinder injection engine 10 is determined on the basis of the operation of the vehicle control device that generates a change in the driving state, that is, the shifting-time torque reduction control means 92 or the first-speed reacceleration torque control means 106. When the combustion state switching means 94 is instructed to preferentially switch from lean combustion to a predetermined combustion in which the mixture ratio is set higher, for example, homogeneous combustion, the combustion state switching means 94 causes the in-cylinder injection engine 10 to operate. 13 is preferentially switched to the homogeneous combustion, the combustion state is not changed during the first speed re-acceleration torque control, as shown in FIG. 13, and the combustion state of the in-cylinder injection engine 10 becomes appropriate. ,
The torque control requested by the control device of the vehicle is successfully performed. For example, since the method of controlling the output torque differs for each combustion state of the in-cylinder injection engine 10, the output torque of the in-cylinder injection engine 10 can be controlled using the same method.

Incidentally, the first speed re-acceleration torque control means 10
In the case where the hysteresis in the rotation direction of the above-mentioned switching condition is not expanded when the first speed re-acceleration torque control is performed by the control unit 6 and the vehicle is switched to the stratified operation region, the ignition timing retard is effectively made as shown in FIG. There is a case where a large shock occurs due to engagement of the one-way clutch F2 that establishes the first speed, as shown by the broken line in FIG.

FIG. 14 shows an electronic control unit 76 for an engine and an electronic control unit 7 for shifting according to another embodiment of the present invention.
8 is a functional block diagram for explaining a main part of the control function of FIG. 14 differs from the embodiment of FIG. 7 in that the switching prohibition command means 126 is provided in place of the hysteresis width change command means 108 and the hysteresis width change means 110. The switching prohibition command means 126 is based on the operation of a vehicle control device that causes a change in the driving state of the vehicle, for example, the shifting torque reduction control 92 and the first speed re-acceleration torque control means 106, that is, the torque reduction during shifting. Based on a request from the control 92 and the first speed re-acceleration torque control means 106, switching of the combustion state of the in-cylinder injection engine 10, for example, switching between lean combustion and stratified combustion or weak stratified combustion, is prohibited. Combustion state switching means 94
Command.

FIG. 15 shows the electronic control unit 7 for the engine.
6 is a flowchart for explaining a main part of the control operation of No. 6, showing a combustion state switching prohibition control routine. FIG.
In S5, the S corresponding to the switching prohibition command means 126
At C1, it is determined whether the torque reduction control during gear shifting performed by the torque reduction control means 92 during gear shifting is being performed, or the first speed re-acceleration torque control performed by the first speed re-acceleration torque control means 106 is being performed. Is determined. This SC
If the determination of 1 is denied, in SC4, normal combustion state switching control using, for example, the normal combustion state switching conditions shown by the solid line and the broken line in FIG. 5 is executed.

However, if the determination at SC1 is affirmative, the switching of the combustion state of the in-cylinder injection engine 10 is preferentially prohibited at SC2 corresponding to the combustion state switching means 94. Next, at SC3, it is determined whether the torque reduction control or the first-speed re-acceleration torque control during the shift determined to be under control at SC1 has been completed. Initially, the judgment of SC3 is denied, so SC2
The following is repeatedly performed. If the determination of SC3 is affirmative during the repetition of the execution of SC2 and subsequent steps, the aforementioned S
At C4, the control is returned to the combustion state switching control using the normal switching conditions, for example, the homogeneous → stratified switching line 100 shown by the solid line in FIG. 5 and the stratified → homogeneous switching line 102 shown by the broken line.

According to this embodiment, the switching prohibition command means 12
6 (SC1), the combustion state of the in-cylinder injection engine 10 is determined based on the operation of the vehicle control device that causes the change in the driving state, that is, the shifting torque reduction control means 92 or the first speed re-acceleration torque control means 106. When the combustion state switching means 94 is instructed to inhibit the switching, the combustion state switching means 94 causes the in-cylinder injection engine 10 to operate.
Since the switching of the combustion state is prohibited, the frequent switching is eliminated, the combustion state of the in-cylinder injection engine 10 becomes appropriate, and the torque control requested by the control device of the vehicle described above is successfully performed. For example, since the method for controlling the output torque differs for each combustion state of the in-cylinder injection engine 10, the in-cylinder injection engine 1
0 output torque can be controlled.

While the embodiment of the present invention has been described with reference to the drawings, the present invention can be applied to other embodiments.

For example, in the vehicle of the above-described embodiment, the in-cylinder injection engine 10 is provided, but another type of engine such as a lean burn engine that performs lean combustion by out-of-cylinder injection may be used. In short, any engine whose combustion state can be switched may be used.

In the above-described embodiment, the switching condition shown in FIG. 5 or FIG. 10 for switching between homogeneous combustion and stratified combustion is used. Stratification → homogeneous switching line 102, 1
The shape of 16 may be various straight lines or curved lines as necessary, and the combustion state to be switched between the weak stratified combustion and the homogeneous combustion or the weak combustion depending on the combustion state of the in-cylinder injection engine 10. It may be between stratified combustion and lean combustion, between stratified combustion and lean combustion, and the like.

In the above-described embodiment, the hysteresis is expanded by shifting a part of the homogeneous-to-stratified switching lines 100 and 114 to the lower rotational speed side. The hysteresis may be expanded by shifting the part toward the high rotation speed side,
The hysteresis may be expanded by displacing a part of the homogeneous to stratified switching lines 100 and 114 or a part of the stratified to homogeneous switching lines 102 and 116 to the low load side or the high load side.

In the vehicle of the above-described embodiment, the torque converter 12 with the lock-up clutch 24 and the stepped automatic transmission 14 are used as the power transmission device. It may be a manual transmission, a fluid coupling or a torque converter and a belt type continuously variable transmission, a traction type continuously variable transmission, another type of continuously variable transmission, or the like. Further, the automatic transmission 14 may be provided with a manual shift mode for switching gears in response to a manual operation, in addition to the automatic shift mode for automatically changing the gear ratio.

The vehicle of the above-described embodiment is provided with the engine control device 76 and the transmission control device 78 connected to each other via a communication line. However, a common arithmetic control device is used. Alternatively, for example, three or more arithmetic and control units provided for each control may be used.

In the above-described embodiment, devices corresponding to the in-shift torque reduction control means 92 and the first speed re-acceleration torque control means 106 have been described as the control devices for the vehicle that generate the change in the driving state. However, another control device such as a device that controls the torque of the in-cylinder injection engine 10 for reducing the release shock or the engagement shock of the lock-up clutch 24 may be used. in short,
What is necessary is just to generate a change in the driving state such as a torque change or a rotation change of the in-cylinder injection engine 10.

For example, when a control device for controlling the torque of the in-cylinder injection engine 10 for reducing the release shock or engagement shock of the lock-up clutch 24 is provided, the lock-up clutch 24
When the lock-up clutch 24 is disengaged, the hysteresis is reduced because the possibility of hunting is low when the lock-up clutch is engaged. When the lock-up clutch 24 is engaged in a slip state (slip control), the lock-up clutch 2
The magnitude of the hysteresis may be changed according to the slip ratio of No. 4.

Although the embodiment of the present invention has been described in detail with reference to the drawings, this is merely an embodiment,
The present invention can be implemented in various modified and improved aspects based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram illustrating the configuration of a torque converter and an automatic transmission provided in a power transmission path of a vehicle according to an embodiment of the present invention.

FIG. 2 is a table illustrating a relationship between a combination of operations of a friction engagement device of the automatic transmission of FIG. 1 and a gear obtained by the combination.

FIG. 3 is a diagram illustrating a control system of a cooperative control device for an engine and a transmission in the vehicle of FIG. 1;

FIG. 4 is a table for explaining a type of a combustion state, an air-fuel ratio, an injection timing, and a torque reduction method of an in-cylinder injection engine provided in the vehicle of FIG. 1;

FIG. 5 is a diagram showing switching conditions used for determining switching of the combustion state in the engine electronic control device of FIG. 3;

FIG. 6 is a diagram showing a shift diagram used for determining a gear shift of the automatic transmission in the electronic shift control device of FIG. 3;

FIG. 7 is a functional block diagram illustrating a main part of control functions of the engine electronic control device and the shift electronic control device of FIG. 3;

8 is a flowchart illustrating a main part of a control operation of the engine electronic control device of FIG. 3;

9 is a time chart for explaining a main part of the operation of the first-speed re-acceleration control when the control of FIG. 8 is performed.

FIG. 10 is a diagram showing a switching condition in another embodiment of the present invention, and is a diagram corresponding to FIG. 5;

FIG. 11 is a functional block diagram illustrating a main part of control functions of an engine electronic control device and a shift electronic control device according to another embodiment of the present invention.

12 is a flowchart illustrating a main part of a control operation of the engine electronic control device in the embodiment of FIG. 11;

13 is a time chart for explaining a main part of the operation of the first-speed re-acceleration control when the control of FIG. 12 is performed.

FIG. 14 is a functional block diagram illustrating a main part of control functions of an engine electronic control device and a shift electronic control device according to another embodiment of the present invention.

FIG. 15 is a flowchart illustrating a main part of a control operation of the engine electronic control device in the embodiment of FIG. 14;

[Explanation of symbols]

10: In-cylinder injection engine (internal combustion engine) 92: Shifting torque reduction control means (vehicle control device) 106: First speed re-acceleration torque control means (vehicle control device) 108: hysteresis width change command means 110: hysteresis Width changing means 122: priority switching instruction means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Noboru Takagi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Takashi Kawai 1 Toyota Town Toyota City, Toyota City Toyota Motor Corporation F Term (Reference) 3D041 AA48 AA53 AA67 AB01 AC01 AC15 AC16 AC18 AD02 AD05 AD07 AD10 AD31 AD41 AE03 AE04 AE09 AE32 3G093 AA04 AA05 AB00 BA03 BA14 CB06 CB08 DA01 DA05 DA06 DA09 DB05 DB11 DB15 EA03 EA03 EB03 FA03 EB03 FA03 HA04 HA16 JA04 JA06 KA11 KA12 KB10 LA00 LA03 LB04 MA01 MA11 NA08 NB02 NB06 NB11 NC02 NE00 NE01 NE13 NE14 NE15 NE27 PA01Z PA10Z PA11Z PA17Z PE01Z PE08Z PF01Z PF03Z PF05Z PF07Z

Claims (5)

[Claims] 1. A control device for an internal combustion engine capable of switching a combustion state, comprising: combustion state switching means for switching a combustion state of the internal combustion engine in accordance with a switching condition having hysteresis; and a hysteresis width change for changing a width of the hysteresis. And a hysteresis width change instructing means for instructing the hysteresis changing means to change the hysteresis width on the basis of the operation of the control device of the vehicle that causes the drive state to change. . 2. The control device for an internal combustion engine according to claim 1, wherein said hysteresis width change instructing means instructs said hysteresis changing means to change said hysteresis width so as to increase said hysteresis width. 3. A control device for an internal combustion engine whose combustion state can be switched, wherein a switching condition having a hysteresis, wherein the width of the hysteresis is determined according to a type of a driving device of a vehicle, is stored in advance. A control device for an internal combustion engine, comprising: switching condition storage means; and combustion state switching means for switching a combustion state of the internal combustion engine according to a switching condition having hysteresis stored in the switching condition storage means. 4. A width of the hysteresis is reduced in a direction in which a stratified combustion region of the internal combustion engine is expanded when the driving device of the vehicle is a manual transmission as compared with an automatic transmission. 4. The control device for an internal combustion engine according to claim 3, wherein the control device is changed to: 5. A control device for an internal combustion engine capable of switching a combustion state, comprising: a combustion state switching means for switching a combustion state of the internal combustion engine; and a request from a vehicle control device for generating a drive state change. Priority switching instruction means for instructing the combustion state switching means to preferentially switch the combustion state of the internal combustion engine from lean combustion to predetermined combustion having a higher mixture ratio than the lean combustion. Control device for an internal combustion engine.