JPH10299546A - Control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a vehicle attaining possible of holding idle operation always stable, in the vehicle with an engine output adjustable by using an electronic intake air amount control valve. SOLUTION: When an engine is placed not in an idle operating condition, based on an operating condition (APS) of an acceleration operating member and an engine speed (Ne), a first target throttle opening (GTHT) is calculated, in accordance with this first target throttle opening, a throttle valve is drive controlled (S10, S12). On the other hand, by an idle detection means, when the engine is detected to be in an idle operating condition, an idle target rotational speed (Nei) is set, based on the operating condition (APS) of the acceleration operating member the idle rotational speed (Nei), a second target throttle opening (θTHT) is calculated, in accordance therewith, the throttle valve is drive controlled (S10, S14, S16).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle, and more particularly, to an engine control technique during idling operation.

[0002]

[Related Background Art] In recent years, a gasoline engine mounted on a vehicle can be operated at a lean air-fuel ratio by directly injecting fuel into an intake pipe injection engine designed to be capable of a lean air-fuel ratio operation or a combustion chamber. Various types of in-cylinder injection-type engines designed in the art have been proposed.

Incidentally, such a gasoline engine capable of operating at a lean air-fuel ratio requires more intake air than at the time of stoichiometric air-fuel ratio operation in order to make the air-fuel ratio lean.
Thus, recently, a throttle valve having a large-diameter intake passage area and electrically opening and closing the throttle valve using a motor, and allowing the intake air amount to be increased or decreased by adjusting the opening of the throttle valve. (Electronic intake air flow control valve) has been developed and put into practical use.

In such an electronic intake air amount control valve,
To obtain an appropriate intake air volume with good response,
The opening of the throttle valve is set according to the operation amount of the accelerator pedal and the engine speed.

[0005]

However, as described above, when the opening of the throttle valve is set in accordance with the operation amount of the accelerator pedal and the engine speed,
It is good when the vehicle is running normally, but when the engine is in the idling operation state, for example, when the engine speed is increased or decreased to operate the compressor according to the ON operation of the air conditioner, that is, When the engine speed changes due to an external load, the opening of the throttle valve also fluctuates in accordance with the increase in the engine speed, so that the idle speed is not kept constant and the idling operation is not stable. There is.

In particular, when the compressor of the air conditioner is operated, the operation of increasing the engine speed and the opening of the throttle valve accordingly is repeated.
This is not preferable because the engine speed may diverge. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle in which the engine output can be adjusted using an electronic intake air amount control valve.
It is an object of the present invention to provide a control device for a vehicle that can stably maintain an idling operation at all times.

[0007]

To achieve the above object, according to the first aspect of the present invention, when the engine is not in the idling operation state, the operation state of the acceleration operation member is detected by the acceleration operation state detection means, and the engine is operated. When the rotation speed of the engine is detected by the rotation speed detecting means, the first target throttle opening degree is calculated by the first target throttle opening degree calculating means based on the operation state of the acceleration operating member and the engine rotation speed, The drive of the throttle valve is controlled in accordance with the first target throttle opening.

On the other hand, when the idle detecting means detects that the engine is in the idling operation state, the idling target rotation speed in the idling operation state is set by the idling target rotation speed setting means, and the operating state of the acceleration operating member is set. The second target throttle opening is calculated by the second target throttle opening calculating means based on the idle target rotation speed and the idle target rotation speed, and the drive of the throttle valve is controlled in accordance with the second target throttle opening. .

Therefore, when the engine is not in the idling operation state, the throttle valve is suitably variably controlled based on the operation state of the acceleration operation member and the engine rotation speed. The throttle opening is substantially fixed even when an external load such as the drive of the compressor is applied, and the engine speed is constantly maintained at a predetermined idle target speed without being constantly increased. The operating state can be ensured.

According to the second aspect of the present invention, when the automatic transmission state detecting means detects that the automatic transmission is in the automatic shift state, and when the idle detecting means detects that the automatic transmission is in the idling operation state, The drive of the throttle valve is controlled based on the calculation result of the second target throttle opening calculation means. Therefore, especially when the automatic transmission is in the automatic shift state, the engine rotational speed is inadvertently increased during the idling operation, and the driving force transmitted to the drive wheels via the automatic transmission is gradually increased. The increase is preferably prevented.

[0011]

An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing one embodiment of a vehicle control device according to the present invention. Hereinafter, the configurations of the vehicle and the control device will be described with reference to FIG. Engine body (hereinafter simply referred to as engine) 1
For example, an in-cylinder injection spark ignition type in-line four-cylinder gasoline engine capable of performing fuel injection in the compression stroke (late injection mode) together with fuel injection in the intake stroke (first injection mode) is applied. The in-cylinder injection type engine 1 can burn at a lean air-fuel ratio, that is, a lean air-fuel ratio, and can easily operate at a rich air-fuel ratio, a stoichiometric air-fuel ratio (stoichio) AFS, and a lean air-fuel ratio. It is possible.

As shown in FIG. 1, an electromagnetic fuel injection valve 4 is mounted on a cylinder head of the engine 1 together with a spark plug 3 for each cylinder, whereby fuel can be directly injected into a combustion chamber. It has been. An intake port is formed in the cylinder head of the engine 1 in a substantially upright direction for each cylinder, and one end of an intake manifold 10 is connected to communicate with each intake port. An exhaust port is formed in the cylinder head in a substantially horizontal direction for each cylinder, and one end of the exhaust manifold 12 is connected to communicate with each exhaust port.

Reference numeral 14 in the drawing denotes a water temperature sensor for detecting a cooling water temperature Tw. Reference numeral 16 denotes a vane-type crank angle sensor (engine rotation speed detecting means) that outputs a crank angle signal SGT at a predetermined crank position (for example, 5 ° BTDC and 75 ° BTDC) of each cylinder. The engine rotation speed Ne can be detected based on the crank angle signal SGT from the sensor 16.

As shown in FIG. 1, the ignition plug 3 is connected to an ignition coil 18 for outputting a high voltage. Also,
A fuel control device 22 is connected to the fuel injection valve 4 via a fuel pipe 20, and the fuel control device 22 is connected to a fuel tank 26 via a fuel pipe 24. More specifically, the fuel control device 22 is provided with a low-pressure fuel pump and a high-pressure fuel pump, whereby the fuel in the fuel tank 26 is supplied to the fuel injection valve 4 at a low fuel pressure or a high fuel pressure, Fuel can be injected from the fuel injection valve 4 into the combustion chamber at a desired fuel pressure.

The in-cylinder injection type engine 1 is already known, and a detailed description thereof will be omitted. An electronic intake air amount control valve, that is, a drive-by-wire type throttle valve (hereinafter referred to as DB) is connected to the intake manifold 10 via a surge tank 28.
WT / B) 30 is connected, and DBW-T
An air cleaner 54 is connected to / B30 via an intake pipe 50.

The maximum flow passage area of the DBW-T / B30 is usually large because the in-cylinder injection type engine 1 needs a large amount of intake air in the latter-stage injection lean mode, particularly when burning at a super lean air-fuel ratio. It is said to be larger than the throttle valve. The DBW-T / B 30 includes a butterfly throttle valve 34 that opens and closes a flow path by driving a stepper motor 32, and a throttle position sensor (hereinafter, referred to as TPS) that detects the opening of the throttle valve 34, that is, the throttle opening θTH. ) 36, and an idle switch (idle detecting means) 38 for detecting an almost fully closed state of the throttle valve 34 to recognize the idle state of the engine 1. The throttle voltage ETPS corresponding to the throttle opening is actually output from the TPS 36, and the throttle opening θTH is recognized based on the throttle voltage ETPS.

The intake pipe 50 is provided with a limp home pipe (bypass passage) 40 which bypasses the DBW-T / B 30 and which can intake air into the intake manifold 10. A limp home pipe of a linear solenoid type is provided in the pipe. Valve 4
2 are interposed. This limp home valve 42
For example, the valve is opened when the DBW-T / B 30 breaks down, and even when the throttle valve 34 is closed, intake at a constant flow rate is possible.

As shown in FIG. 1, an automatic transmission (A / A) is connected to an output shaft 60 connecting the engine 1 and the drive wheels 62.
T) 64 is interposed. The automatic transmission 64 is, for example, an automatic transmission having a torque converter capable of transmitting a driving force via a fluid coupling. Further, an output shaft 60 of the engine 1 is provided with an air conditioner (not shown) (vehicle air conditioner).
Is connected to the output shaft 60 so as to be synchronously rotatable.

In the cabin of the vehicle, an input / output device, a storage device (RO) for storing control programs, control maps, and the like are provided.
M, RAM, BURAM, etc.), central processing unit (CP
U), an ECU (electronic control unit) 70 including a timer counter and the like is installed.
Thus, comprehensive control of the engine 1 is performed. E
In addition to the various sensors described above, the CU 70 is further connected to an accelerator pedal (acceleration operation member) 74 and outputs an accelerator voltage EAPS corresponding to the accelerator opening degree.
APS 72 is connected, and information from these sensors and the like is input. In fact, APS72
Outputs the accelerator voltage EAPS, and the accelerator opening θACC is recognized based on the accelerator voltage EAPS.

The ECU 70 determines the fuel injection mode, the fuel injection amount, the ignition timing, the intake air amount, etc., based on the detected information, and determines the fuel injection valve 4, ignition coil 18, fuel control device 22, DBW -Drive control of the stepper motor 32 and the like of the T / B 30. Further, the ECU 70 includes a shift mode switching of the automatic transmission 64, that is, a parking range (P range), a reverse range (R range),
An inhibitor switch (automatic shift state detecting means) 68a of a select lever unit 68 for switching between a drive range (D range) and a manual range (M range) is connected, and the select switch 69 can be operated from the inhibitor switch 68a. A corresponding signal is supplied to the ECU 70. When the select lever 69 is in the drive range (D range) position and a signal corresponding to the D range is output to the ECU 70, the automatic transmission 64 is automatically controlled by the ECU 70.

Although not described, the input side of the ECU 70 is connected to a large number of switches and sensors (not shown) in addition to the various sensors described above. Etc. are also connected. Hereinafter, the combustion control of the engine 1 configured as described above will be described. When the engine 1 is in a cold state, when the driver turns on the ignition key, a signal for starting is supplied from the ECU 70 to the fuel control device 22, and the low pressure fuel pump of the fuel control device 22 activates the fuel injection valve 4.
Is supplied with low fuel pressure fuel.

When the driver operates the ignition key, the engine 1 is cranked by a cell motor (not shown), and the combustion control is started. At this point, combustion control for starting is performed. Specifically, here, the first-stage injection mode (that is, the intake stroke injection mode) is selected, and based on a signal from the ECU 70,
The fuel injection valve 4 has a relatively rich air-fuel ratio.
The fuel is injected from.

When the start of the engine 1 is completed and the engine 1 starts idling, the fuel control device 22 supplies a relatively high fuel pressure fuel to the fuel injection valve 4 by operating a high pressure fuel pump. When the cooling water temperature Tw rises to a predetermined value and the engine 1 warms up, normal combustion control is performed. Specifically, the switching of the fuel injection mode is controlled based on the fuel injection mode setting map shown in FIG. That is, depending on the target average effective pressure Pe and the engine rotation speed information Ne, the fuel injection mode is the latter-stage injection lean mode, the first-stage injection lean mode, the stoichiometric feedback mode (hereinafter, referred to as the SF / B mode), the open loop Mode (hereinafter referred to as O / L mode). Here, other than the latter-stage injection lean mode, the former-stage injection mode is the former-stage injection mode, and the latter-stage injection lean mode is a lean air-fuel ratio operation mode in the former-stage injection mode, and SF / B
The mode indicates an operation mode at a stoichiometric air-fuel ratio AFS, and the O / L mode indicates an operation mode at a rich air-fuel ratio.

For example, when the engine 1 is in a low load range, such as during idling or low-speed running, the fuel injection mode is set to the late lean mode, and fuel injection is performed during the compression stroke. On the other hand, when the engine 1 is in the middle to high load range as in the case of running at a medium to high speed, the fuel injection mode is set to the first injection mode (first injection lean mode, SF
/ B mode, O / L mode), and fuel injection is performed in the intake stroke.

Hereinafter, the combustion control when the operating state of the engine 1 is an idling operation or a low-speed running and the fuel injection mode is the late injection lean mode will be described in more detail. Here, the case where the shift mode is in the D range position and the automatic transmission 64 is in the automatic shift state will be particularly described. In the late injection lean mode, the ECU 7
In step 0, first, a throttle opening setting routine (throttle control means) shown in FIG. 3 is executed.

In step S10 of FIG. 3, it is determined whether or not the idle switch 38 is on and the engine 1 is in an idling state. Engine 1 with a determination result of false (No)
If it is determined that is not in the idling operation state, the process proceeds to step S12. In step S12, the target throttle opening θTHT when the engine 1 is not in the idling state (during low-speed running) is set. When the engine 1 is not in the idling operation state, first, the engine 1 corresponds to the target output based on the engine rotation speed information Ne actually detected from the crank angle sensor 16 and the accelerator opening information θACC based on the accelerator voltage EAPS from the APS 72. The target average effective pressure Pe is calculated. Specifically, as shown in FIG. 4A, the engine speed Ne and the accelerator opening degree information θACC
A map indicating the relationship between the target average effective pressure Pe and the target average effective pressure Pe is set in advance, and the target average effective pressure Pe is read from this map.

The target throttle opening degree (first target throttle opening degree) θTHT of the throttle valve 34 is determined based on the target average effective pressure Pe thus obtained and the actually detected engine speed information Ne. Calculate (first
Target throttle opening calculating means). For details, see FIG.
As shown in FIG. 5, a map indicating a relationship between the target average effective pressure Pe and the engine rotation speed Ne and the target throttle opening θTHT is set in advance, and the target throttle opening θTHT is
Read from this map.

In practice, the average engine speed information Nef filtered by the following equation is used as the engine speed information Ne. Nef (n) = (1−Kn) · Ne + Kn · Nef (n−1) where Nef (n) is the current average engine speed information Ne.
f, and Nef (n−1) is the previous average engine speed information Nef. Kn is a predetermined filter constant.
However, the predetermined filter constant Kn is, for example, a value of 0.98 during a steady operation, and is, for example, a value of 0 during a transient operation.
It is said.

On the other hand, if the determination result of step S10 is true (Y
If it is determined in es) that the engine 1 is in the idle operation state, the process proceeds to step S14. Step S14
Then, a predetermined target engine rotational speed (idle target rotational speed) Nei for idling is set (idle target rotational speed setting means). That is, when the engine is idling, the predetermined target engine speed Nei is set irrespective of the engine speed Ne detected from the crank angle sensor 16. This target engine speed Nei
Indicates various external loads applied to the engine 1 and the cooling water temperature Tw.
Is determined in advance according to. That is, for example, the air conditioner is turned on, and the engine 1
6, the target engine speed N
ei is determined in advance to a value higher than normal, and in step S14, the value higher than normal is set as the target engine rotation speed Nei.

In the next step S16, based on the target engine speed Nei and the accelerator opening information θACC based on the accelerator voltage EAPS from the APS 72,
The target average effective pressure Pe corresponding to the target output is calculated. More specifically, as shown in FIG. 5A, the target engine speed Nei and the accelerator opening degree information θACC and the target average effective pressure Pe
Is set in advance separately from the map shown in FIG. 4A, and the target average effective pressure Pe is read from this map.

Then, a target throttle opening (second target throttle opening) θTHT is calculated based on the target average effective pressure Pe thus obtained and the target engine rotation speed Nei (second target throttle opening). Calculation means). More specifically, as shown in FIG. 5B, a map showing the relationship between the target average effective pressure Pe and the engine rotation speed information Ne and the target throttle opening θTHT is also different from the map shown in FIG. 4B in advance. Is set and the target throttle opening θTHT
Is read from this map.

As described above, when the engine 1 is in the idling state, the target throttle opening θTHT is set by using the predetermined target engine speed Nei, so that the idle speed, that is, the crank speed is adjusted according to the external load. Even if the engine speed Ne detected by the angle sensor 16 changes, the target throttle opening θTHT is preferably prevented from fluctuating in response to this. For example, when the air conditioner is not turned on, the compressor 6 is turned on.
6, the engine speed Ne increases to operate well,
The target throttle opening θTHT increases in accordance with this rise,
The engine rotation speed Ne further increases, and the driving force is gradually increased and transmitted to the driving wheels 62 via the automatic transmission 64, for example. This is prevented during idling, The idle rotation speed is always kept constant, and a good idle operation state is ensured.

Also, based on the target average effective pressure Pe obtained from FIGS. 4A and 5A, the target A / F
Each combustion parameter such as (target air-fuel ratio), injection end timing Tend, and ignition timing Tig is set. When the target A / F is set, the fuel injection time Tinj is determined based on the target A / F.
Is set, and the fuel injection amount is determined. In the late injection lean mode, the target A / F is, for example, about 30 to 40.

As described above, when each combustion parameter is set, a signal corresponding to the target throttle opening θTHT is supplied to the stepper motor 32 of the DBW-T / B 30, and the opening of the throttle valve 34 is variably operated. Thus, the intake air amount is adjusted, and a signal corresponding to the fuel injection time Tinj is supplied to the fuel injection valve 4, and the fuel injection time Tinj
An amount of fuel corresponding to j is injected from the fuel injection valve 4. At the same time, a signal corresponding to the fuel injection end timing Tend is also supplied to the fuel injection valve 4, and the fuel injection timing is determined. Then, an ignition timing Tig signal is supplied to the ignition coil 18. As a result, optimal combustion control is realized.

As described in detail above, according to the vehicle control system of the present invention, in the combustion control of the engine 1, the engine speed Ne, which is normally detected, and the accelerator opening information θACC are usually used. The target throttle opening .theta.THT is calculated to obtain an appropriate intake air amount of the engine 1. When the engine 1 is in an idle operation state, the target throttle opening .theta.THT is determined in advance. The calculation is performed based on the predetermined engine rotation speed Nei and the accelerator opening degree information θACC to obtain the intake air amount.

Therefore, during the idling operation of the engine 1,
For example, even if the air conditioner is turned on, that is, an external load is applied to the output of the engine 1 and the engine rotation speed Ne is increased accordingly, the target throttle opening θTHT is preferably prevented from fluctuating. The rotation speed is always kept stable. Therefore, during the idling operation, the driving force is transmitted to the driving wheels 6 via the automatic transmission 64.
Thus, the idle operation state can be favorably maintained without being gradually increased to 2 and transmitted.

In the above embodiment, the engine 1 is an in-cylinder injection type engine. However, the invention is not limited to this. Any type of engine may be used as long as a drive-by-wire type throttle valve (DBW-T / B) is provided. The present invention can be applied to an engine. Further, in the above embodiment, the combustion control in the case where the automatic transmission 64 is in the automatic shift state has been described. However, the present invention can be suitably applied even when the automatic transmission 64 is not in the automatic shift state.

In the above-described embodiment, when the target throttle opening θTHT is obtained, the target average effective pressure Pe is first obtained, and then the target throttle opening θTHT is obtained. However, the engine speed Ne and the accelerator opening Information θACC or target engine speed Nei and accelerator opening degree information θAC
It is also possible to obtain the target throttle opening θTHT directly from C.

[0039]

As described in detail above, claim 1 is as follows.
According to the vehicle control device, when the engine is not in the idle operation state, the throttle valve can be suitably variably controlled based on the operation state of the acceleration operation member and the engine rotation speed, while when the engine is in the idle operation state. For example, even when an external load such as driving of a compressor of an air conditioner is applied, the throttle opening can be substantially fixed.
It is possible to satisfactorily keep the engine rotation speed substantially constant at the predetermined idle target rotation speed without increasing the engine rotation speed. As a result, a stable idle operation state can always be ensured.

According to the vehicle control device of the second aspect, the automatic transmission has an automatic transmission, and particularly when the automatic transmission is in the automatic shift state, an inadvertent increase in the engine speed during idling is prevented. Thus, it is possible to preferably prevent the driving force transmitted to the driving wheels via the automatic transmission from unintentionally increasing.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an in-cylinder injection type spark ignition engine mounted on a vehicle and a control device of the vehicle.

FIG. 2 is a diagram showing a fuel injection mode setting map.

FIG. 3 is a flowchart illustrating a throttle opening degree setting routine according to the present invention.

FIG. 4 shows engine rotation speed Ne and accelerator opening degree information θA.
9 is a map showing a relationship between CC and a target average effective pressure Pe, and a map showing a relationship between the target average effective pressure Pe, the engine rotation speed Ne, and the target throttle opening θTHT.

FIG. 5 is a map showing the relationship between the target engine speed Nei and accelerator opening information θACC and the target average effective pressure Pe, and the relationship between the target average effective pressure Pe and the target engine speed Nei and the target throttle opening θTHT. It is a map.

[Explanation of symbols]

 Reference Signs List 1 engine 16 crank angle sensor (engine rotation speed detecting means) 30 DBW-T / B (throttle valve) 32 stepper motor 34 throttle valve 36 TPS 38 idle switch (idle detecting means) 64 automatic transmission 66 compressor 68a inhibitor switch (automatic Shift state detecting means) 70 electronic control unit (ECU) 72 APS (acceleration operation state detection means) 74 accelerator pedal (acceleration operation member)

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 41/16 F02D 41/16 E

Claims (2)

[Claims] 1. A control device for a vehicle including an engine having an acceleration operation member and a throttle valve electrically driven in accordance with an operation of the acceleration operation member, wherein the acceleration detecting the operation state of the acceleration operation member An operation state detection unit, an engine rotation speed detection unit that detects the rotation speed of the engine, and a first target throttle opening degree that calculates a first target throttle opening based on an output result of the acceleration operation state detection unit and the engine rotation speed detection unit. Target throttle opening calculation means; idle detection means for detecting that the engine is in an idle operation state; idle target rotation speed setting means for setting an idle target rotation speed in the idle operation state; and the acceleration operation state Calculating a second target throttle opening based on the output results of the detecting means and the idle target rotational speed setting means; (2) when the idle operation state is not detected by the idle detection means, the throttle valve is driven based on the calculation result of the first target throttle opening degree calculation means while the idle operation state is not detected by the idle detection means; And a throttle control means for driving the throttle valve based on the calculation result of the second target throttle opening degree calculation means. 2. The vehicle further includes: an automatic transmission connected to the engine; and an automatic transmission state detecting unit that detects that the automatic transmission is in an automatic transmission state. The throttle control unit includes: When the automatic shift state detecting means detects the automatic shift state and the idle detecting means detects the idle operation state, the result of the calculation by the second target throttle opening degree calculating means is obtained. The control device for a vehicle according to claim 1, wherein the throttle valve is driven based on the control signal.