JP3518168B2 - Engine torque control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine torque control device.

[0002]

2. Description of the Related Art A conventional engine torque control device is disclosed, for example, in Japanese Patent Laid-Open No. 62-110536.

[0003]

However, in such a conventional engine torque control device, the target throttle valve opening is directly searched from the target engine torque and the engine rotation speed. This is because it is set on the premise of a predetermined air-fuel ratio (for example, a theoretical air-fuel ratio), and there is a problem that it cannot be applied as it is to an engine that variably controls the air-fuel ratio according to the operating state.

For example, when the target air-fuel ratio is set to lean, it is necessary to change the target intake air amount according to the change of the target air-fuel ratio, such as requiring a larger intake air amount than when the target air-fuel ratio is set. There is a need to change the target throttle valve opening accordingly. Furthermore, since the response speed differs between the intake air amount and the fuel supply amount, if the target air-fuel ratio changes or the target engine torque changes as described above, the engine torque fluctuates due to the intake air amount delay. It may happen.

The present invention has been made in view of the above conventional problems, and in an engine in which the target air-fuel ratio is variably controlled according to the operating state, the engine can be operated even when the target air-fuel ratio or the target engine torque changes. An object of the present invention is to provide an engine torque control device capable of suppressing torque fluctuations.

[0006]

[0007]

[0008]

Therefore, according to the first aspect of the invention, as shown in FIG. 1, the throttle valve control device for controlling the intake air amount by controlling the opening degree of the throttle valve interposed in the intake system of the engine. And a fuel supply amount control device for controlling the fuel supply amount to the engine, and by controlling the intake air amount and the fuel supply amount, the engine torque is controlled to a target value while controlling the equivalence ratio to a target value. In a torque control device for an engine, the operating state detecting means for detecting an engine operating state including an engine speed and an intake air flow rate, and a target equivalence ratio for computing a target equivalence ratio according to the operating state of the engine. A ratio calculating means, a target intake air amount calculating means for calculating a target intake air amount based on the operating state of the engine and the target equivalent ratio, and the target intake air amount are obtained. Target throttle valve opening calculation means for calculating a target throttle valve opening, a corrected target intake air quantity calculation means for calculating a corrected target intake air quantity by phase-correcting the target intake air quantity, and the target intake air quantity And a corrected target intake air amount, the corrected target equivalent ratio is corrected to calculate the corrected target equivalent ratio, the intake air flow rate detected by the operating state detecting unit, and And a target fuel supply amount calculating means for calculating a target value of the fuel supply amount based on the corrected target equivalent ratio.

Action / Effect A target equivalence ratio is calculated according to the engine operating state, a target intake air amount is calculated based on the operating state and the target equivalence ratio, and a target throttle is set to obtain the target intake air amount. The valve opening is calculated and the throttle valve is controlled. Here, as described above, the target intake air amount changes when the target equivalence ratio, the target engine torque, or the like changes, but the corrected target intake air amount is calculated by performing phase correction on the target intake air amount.

The target equivalence ratio is corrected based on the ratio between the corrected target intake air amount and the target intake air amount before correction, and the fuel supply amount is corrected based on the corrected target equivalence ratio and the actual intake air amount. By calculating and controlling the target value of, it is possible to control the intake air amount and the fuel supply amount in phase with each other, so that the engine torque fluctuation when the target equivalence ratio changes and the target engine torque change The actual engine torque response delay is suppressed.

According to the second aspect of the present invention, the target intake air amount calculating means calculates the target basic intake air amount corresponding to the theoretical air-fuel ratio based on the operating state of the engine, and the target basic intake air amount. The target intake air amount corresponding to the target equivalence ratio is calculated based on the target equivalence ratio and the target equivalence ratio.

Action / Effect When setting the target intake air amount according to the engine operating condition so as to obtain the target engine torque, it is possible to set the target intake air amount at once so as to simultaneously satisfy the target equivalence ratio. However, the target basic intake air amount set for a certain stoichiometric air-fuel ratio has a small change range (dynamic range) of the set value, and the amount of data required for calculation can be minimized. The correction target intake air amount calculation can also be performed by a simple calculation only by converting it into a target equivalent ratio.

According to a third aspect of the present invention, the operating condition detecting means includes an accelerator operation amount detecting means, and the target intake air amount calculating means is based on the accelerator operation amount and the engine rotation speed. The target intake air amount is calculated, and the target equivalent ratio calculating means calculates the target equivalent ratio based on the accelerator operation amount and the engine rotation speed.

Action / Effect The accelerator operation amount is detected as the engine load desired by the driver. Then, based on the basic engine operating state consisting of the accelerator operation amount and the engine rotation speed, a target intake air amount for obtaining a target engine torque and a target equivalence ratio are calculated. .

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a system configuration of one embodiment of the present invention (common to each control embodiment described later). The accelerator operation amount sensor 1 detects the depression amount of the accelerator pedal depressed by the driver as an engine load desired by the driver.

The crank angle sensor 2 as the engine speed detecting means generates a position signal for each unit crank angle and a reference signal for each cylinder stroke phase difference, and measures the number of generated position signals per unit time. Due to
Or by measuring the reference signal generation period,
The engine speed can be detected. Air flow meter 3
Detects the intake air amount into the engine 4 (intake air amount per unit time = intake air flow rate).

The water temperature sensor 5 detects the cooling water temperature of the engine. The engine 4 is provided with a fuel injection valve 6 that is driven by a fuel injection signal to inject and supply fuel, and a spark plug 7 that is mounted in a combustion chamber and ignites.
A throttle valve 9 is provided in the intake passage 8 and a throttle valve control device 10 capable of electronically controlling the opening of the throttle valve 9 is provided.

Detection signals from the various sensors are input to the control unit 11, which controls the throttle valve control device 10 according to the operating state detected based on the signals from the sensors. Via the throttle valve 9, the fuel injection valve 6 is driven to control the fuel injection amount (fuel supply amount), the ignition timing is set, and the ignition plug 7 is ignited at the ignition timing. Take control.

FIG. 3 shows a functional configuration of an embodiment according to the invention of claim 1. The target engine torque calculation unit A is input with the accelerator operation amount APS detected by the accelerator operation amount sensor 1 and the engine rotation speed Ne calculated based on the detection value of the crank angle sensor 2 and determined by these. Target engine torque t according to the operating state
Te is calculated. Here, the target engine torque tTe
Can be substituted with a value given by an external command.

The calculated target engine torque tTe and engine speed Ne are input to the target basic intake air amount calculation section B, and the target engine torque corresponding to the operating state determined by the input values is the theoretical air-fuel ratio. The target basic intake air amount tTP1 is calculated as a value corresponding to the intake air amount obtained in. Specifically, the data of the target basic intake air amount tTP1 obtained experimentally in advance is used as the target engine torque t.
A method may be used in which Te and engine speed Ne are stored in a map having parameters and are searched from the map. The target basic intake air amount tTP1 is the basic fuel injection amount (pulse width) corresponding to the intake air amount for each intake stroke, and the intake air amount itself for each intake stroke is detected by the air flow meter 3. Either the intake air amount per unit time or the fuel amount corresponding to the intake air amount at the theoretical air-fuel ratio may be used.

The target equivalent ratio calculating section C which constitutes the target equivalent ratio calculating means has the calculated target engine torque tT.
e and the engine rotation speed Ne are input, and the target equivalent ratio tDML1 is calculated according to the target air-fuel ratio corresponding to the operating state. This target equivalence ratio tDML1 can also be calculated by searching the map. The target equivalent ratio tDML1
Is calculated as the theoretical air-fuel ratio / target air-fuel ratio, but this value may be corrected by the cooling water temperature Tw.

The target intake air amount calculation section D divides the target basic intake air amount tTP1 by the target equivalent ratio tDML1 to obtain a target intake air amount tTP2 corresponding to the target air-fuel ratio.
Is calculated. Here, the target intake air amount tTP2 corresponding to the target air-fuel ratio is the intake air amount determined so that the target engine torque can be obtained at the target air-fuel ratio. The target intake air amount calculation unit D constitutes a target intake air amount calculation means together with the target basic intake air amount calculation unit B.

The fuel consumption rate correction coefficient computing unit E inputs the target equivalent ratio tDML1 and, based on the value corresponding to the target air-fuel ratio, calculates the fuel supply amount according to the lean fuel consumption rate (fuel consumption rate) improvement characteristic. Fuel consumption rate correction coefficient FCra for correction
Calculate te. A target intake air amount tTP3 obtained by multiplying the target intake air amount tTP2 by a fuel consumption rate correction coefficient FCrate and an engine rotation speed Ne are input to a target throttle valve opening calculation unit F as target throttle valve opening calculation means. The target throttle valve opening tTPS is calculated. The target throttle valve opening tTPS is the target equivalence ratio tDML.
Target intake air amount tTP which is the target intake air amount in 1
3 is a target throttle opening degree for supplying 3.

The signal of the target throttle valve opening tTPS is input to the throttle valve control device 10, whereby the throttle valve control device 10 causes the throttle valve 8 to operate.
To drive the target throttle valve opening tTPS. The target intake air amount tTP3 is input to the phase operating unit G, and a corrected target intake air amount tTP4 with a phase shift is calculated by a weighted average process or the like. The function of the phase operating unit G constitutes a correction target intake air amount calculation means.

The corrected target equivalent ratio calculating unit H, which constitutes the corrected target equivalent ratio calculating means, has the target intake air amount tTP3,
The target equivalence ratio tDML is multiplied by the ratio tTPrate to the target intake air amount tTP4 which has been subjected to the phase correction to calculate the corrected target equivalence ratio tDML2. Next, the fuel supply amount will be described. The fuel supply amount is calculated by the basic fuel supply amount calculation unit I1 and the corrected fuel supply amount calculation unit I2 which constitute the target fuel supply amount calculation means.

The intake air amount Q per unit time detected by the air flow meter 3 and the engine rotation speed Ne are input to the basic fuel supply amount calculation unit I1, and thereby one intake stroke at the theoretical air-fuel ratio is obtained. The basic fuel injection pulse width TP corresponding to the intake air amount per hit is calculated. The corrected fuel supply amount calculation unit I2 uses the basic fuel injection pulse width T
The effective fuel injection pulse width TE is calculated by multiplying P by the corrected target equivalent ratio tDML2, and the effective fuel injection pulse width T is calculated.
The final fuel injection pulse width TI is calculated by adding the invalid pulse width TS corresponding to the battery voltage to E.

An injection pulse signal having the fuel injection pulse width TI is output to the fuel injection valve 6, and the fuel injection valve 6 is driven to inject and supply a fuel amount corresponding to the target air-fuel ratio. By doing so, the response delay of the actual engine torque with respect to the change of the target engine torque due to the response delay of the intake air and the disturbance of the actual engine torque at the time of the change of the target equivalence ratio due to the response delay of the intake air occur. Can be prevented.

For example, FIG. 4 shows a case where the target equivalence ratio tDML is constant and the target engine torque tTe is increased. In the figure, the left side shows the state of the present embodiment in which no phase correction is performed and the right side performs the phase correction. In this case, the target equivalence ratio tDML is constant, but the target engine torque tT
Since e becomes large, the target basic intake air amount tTP1 also becomes large, and along with this, the target intake air amounts tTP2, tTP.
3 and the target throttle valve opening tTPS increase.

On the other hand, since the basic fuel injection pulse width TP increases with a delay due to the response delay of the intake air due to the volume of the intake system, if the effective fuel injection pulse width TE is TP × tDML, the effective fuel injection pulse width TE. Also grows late. As a result, the actual engine torque also increases with a delay. Here, the target intake air amount tT is added to the target equivalence ratio tDML.
The ratio tTPra between P3 and the target intake air amount tTP4 that has the same phase as the basic fuel injection pulse width TP and has undergone the phase correction.
If the corrected target equivalence ratio tDML2 is multiplied by te and the effective fuel injection pulse width TE is set to TP × tDML2, the corrected target equivalence ratio tDML2 becomes large corresponding to the response delay of intake air. It can be avoided. There are cases where the phase correction is delayed (equivalent ratio change) and cases where it is advanced (torque change).

Next, FIG. 5 shows a case where the target engine torque tTe is constant and the target equivalent ratio tDML is made lean. Since the target engine torque tTe is constant, the target basic intake air amount tTP1 is constant, but the target equivalent ratio tD
Since ML1 becomes smaller, the target intake air amount t also in this case.
TP2, tTP3 and the target throttle valve opening tTPS increase.

On the other hand, since the basic fuel injection pulse width TP increases with a delay due to the intake response delay due to the volume of the intake system, the effective fuel injection pulse width TE calculated by TP × tDML once decreases. As a result, the actual engine torque is once reduced. Therefore, as in the case where the target engine torque tTe changes, a corrected target equivalent ratio tDML2 obtained by multiplying the target equivalent ratio tDML1 by tTPrate is obtained, and the effective fuel injection pulse width TE is TP ×.
If tDML2 is set, the correction target equivalent ratio tDML2 has the same phase as the response delay of the intake air, and thus such disturbance of the actual engine torque can be avoided.

In this embodiment, the accelerator operation amount A
The target engine torque tTe is once calculated from PS and the engine rotation speed Ne, and the target intake air amount tTP3 is obtained from the target engine torque tTe and the engine rotation speed Ne. The target intake air amount tTP3 may be directly obtained from the speed Ne.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration and function of the invention according to claim 1 .

FIG. 2 is a diagram showing a system configuration of an embodiment of the present invention.

FIG. 3 is a block diagram showing a functional configuration of the above embodiment.

FIG. 4 is a time chart showing the operation when the target engine torque changes in the above embodiment.

FIG. 5 is a time chart showing the operation when the target equivalent ratio of the above embodiment changes.

[Explanation of symbols]

1 Accelerator operation amount sensor 2 crank angle sensor 3 Air flow meter 4 engine 5 Water temperature sensor 6 Fuel injection valve 9 Throttle valve 10 Throttle valve control device 11 Control unit A Target engine torque calculation unit B Target basic intake air amount calculator C Target equivalence ratio calculator D Target intake air amount calculator E Fuel consumption correction coefficient calculator F Target throttle valve opening calculation unit G phase operation unit H correction target equivalent ratio calculator I1 Basic fuel supply amount calculation unit I2 Corrected fuel supply amount calculation unit

Claims (3)

(57) [Claims] 1. A throttle valve control device for controlling an intake air amount by controlling an opening of a throttle valve interposed in an intake system of an engine, and a fuel supply amount control device for controlling a fuel supply amount to an engine. In the torque control device for an engine, the engine torque is controlled to a target value while controlling the equivalence ratio to a target value by controlling the intake air amount and the fuel supply amount. An operating condition detecting means for detecting an engine operating condition including an intake air flow rate; a target equivalent ratio calculating device for calculating a target equivalent ratio according to the operating condition of the engine; and an operating condition of the engine and the target equivalent ratio. Target intake air amount calculation means for calculating a target intake air amount based on the above, and a target throttle for calculating a target throttle valve opening for obtaining the target intake air amount Depending on the ratio of the target intake air amount and the corrected target intake air amount, a valve opening calculation unit, a corrected target intake air amount calculation unit for phase-correcting the target intake air amount to calculate a corrected target intake air amount, Based on the corrected target equivalent ratio, the corrected target equivalent ratio calculating means for correcting the target equivalent ratio to calculate the corrected target equivalent ratio, the intake air flow rate detected by the operating state detecting means, and the corrected target equivalent ratio. An engine torque control device comprising: a target fuel supply amount calculation means for calculating a target value of the supply amount; 2. The target intake air amount calculation means calculates a target basic intake air amount corresponding to a theoretical air-fuel ratio based on the operating state of the engine, and based on the target basic intake air amount and the target equivalent ratio. The engine torque control apparatus according to claim 1, wherein a target intake air amount corresponding to the target equivalence ratio is calculated. 3. The operating state detecting means includes means for detecting an accelerator operation amount, and the target intake air amount calculating means calculates a target intake air amount based on the accelerator operation amount and an engine speed. The engine torque control device according to claim 1 or 2 , wherein the target equivalent ratio calculation means calculates a target equivalent ratio based on the accelerator operation amount and the engine rotation speed.