JPH07102786B2 - Engine controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention converts an accelerator operation amount into an electric amount and controls an engine output adjusting means such as a throttle valve in accordance with the electric amount. The present invention relates to an engine control device, which relates to an engine control device which determines a target vehicle speed based on an accelerator operation amount and controls an engine output so as to obtain the target vehicle speed.

(Prior Art) In a general automobile, the accelerator pedal and the throttle valve are mechanically connected, and the opening degree of the throttle valve is uniquely determined by the depression amount of the accelerator pedal. It was impossible to change the relationship with the opening of the throttle valve according to the running state of the vehicle. Therefore, conventionally, various throttle control methods have been proposed in which the throttle valve is electrically controlled with a predetermined characteristic with respect to the depression amount of the accelerator pedal. Further, for example, as disclosed in Japanese Patent Laid-Open No. 60-111029, in controlling the throttle valve with respect to the depression amount of the accelerator pedal, the target vehicle speed is determined based on the accelerator operation amount, and this target vehicle speed is It is also known to control the throttle valve so that it can be obtained.

However, if the actual vehicle speed is simply fed back to the target vehicle speed and the throttle valve is controlled so that the target vehicle speed is obtained, the actual vehicle speed may change due to changes in the tread condition during traveling, traveling wind, etc. The time required to reach to has varied, which has been a problem in achieving the desired stable vehicle speed control.

(Object of the Invention) In view of the above circumstances, the present invention determines the target vehicle speed based on the accelerator operation amount, and when the engine output is controlled so as to obtain this target vehicle speed, the influence of disturbance is prevented. An object of the present invention is to provide an engine control device capable of performing stable vehicle speed control.

(Structure of the Invention) In the present invention, a target vehicle speed is determined based on an accelerator operation amount, and an engine output is controlled so as to obtain the target vehicle speed. In the feedback obtained from the target vehicle speed and the current vehicle speed. It is characterized by comprising means for correcting the control amount with a correction value obtained from the degree of change of the current vehicle speed.

(Effects of the Invention) According to the present invention, the control amount of the engine output is determined by immediately feeding back the fluctuation amount of the vehicle speed due to the disturbance, so that even if the influence of the disturbance such as the change of the running resistance is exerted,
The variation in the time until the target vehicle speed V _T is reached is eliminated, and ideal vehicle speed control that balances stability and responsiveness becomes possible.

(Example) Hereinafter, one example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a system configuration diagram of an engine control device according to the present invention. 1 is an engine, 2 is a clutch, 3 is a transmission, 4 is a throttle valve, 5 is a control unit including a microcomputer, and 6 is a throttle opening. Sensor, 7 is a vehicle speed sensor, 8 is a clutch stroke sensor, and 9 is an actuator for the throttle valve 4.
It is a DC motor. And in the control unit 5,
Accelerator opening α indicating the amount of depression of the accelerator pedal, throttle opening θ from the throttle opening sensor 6, vehicle speed V from the vehicle speed sensor 7, clutch stroke from the clutch stroke sensor 8, gear position from the transmission 3, etc. Signals representing the steering angle, the brake operation, etc. are input, and the control unit 5 is configured to generate an output signal for driving the DC motor based on these input signals to control the throttle valve 4. .

FIG. 2 is a diagram for explaining the basic operation of the throttle valve control system according to the present invention. When the driver depresses the accelerator pedal 11, the accelerator opening signal generator 12 outputs a signal corresponding to the accelerator opening α. appear. The information detection unit 13 detects the gear position, the vehicle speed V, etc., and calculates the acceleration g from the vehicle speed V. The control unit 14, which corresponds to the control unit 5 in FIG. 1, uses the target accelerator opening signal generator 12 to output the accelerator opening α and the target information based on the signal output from the information detector 13. the target throttle opening degree determining section 15 for determining a throttle opening theta _T, the more the feedback control unit 16 for feedback control to approximate the actual throttle opening theta to the target throttle opening theta _T. Feedback control unit 16
Output is the servo drive unit equivalent to the DC motor 9 in FIG.
17 and the servo drive unit 17 opens and closes the throttle valve 4. The opening θ of the throttle valve 4 is
The feedback control unit 16 detects a feedback signal from the throttle opening signal generator 18 corresponding to the throttle opening sensor 6 in FIG.
Feedback to. This feedback control unit 16
The control operation performed by is PID control (proportional operation + integral operation + derivative operation) with a fast response speed.

The target throttle opening degree determining unit 15 determines the target throttle opening degree θ _T based on the accelerator opening degree α when the vehicle is traveling at a low speed or when the engine is idling. FIG. 3 shows a block diagram of the throttle control in that case. In this throttle control, the target throttle opening θ _T is determined on the basis of the accelerator opening α, but the control equation representing the target throttle opening θ _T is shown in the following equation (1). Note that G ₁ ,
G ₂ and G ₃ are constants representing proportional gain, integral gain and derivative gain, respectively.

θ _T = G ₁ (θ _T −θ) + G ₂ ∫ (θ _T −θ) dt + G ₃ (θ _T −θ) ′ …… (1) Since it is necessary to control this equation (1) in time units. , It is necessary to obtain a value differentiated with respect to time. Therefore, if θ _T is differentiated, θ _T ′ = G ₁ (θ _T −θ) ′ + G ₂ (θ _T −θ) + G ₃ (θ _T −θ) ″… (2) Here, the throttle opening deviation θ _T −θ = EN is set,
EN is the throttle opening deviation in the previous control cycle
1. If the throttle opening deviation in the control cycle two times before is EN2, from equation (2), θ _T ′ = G ₁ * (EN−EN1) + G ₂ * EN + G ₃ * {(EN−EN1) − (EN1 _{-EN2)} = G 1 * (} EN-EN1) + G 2 * EN + G 3 * (EN2 * EN1 + EN2) ...... (3) in such a throttle control, the movement of the throttle valve corresponding to the accelerator opening degree It is easy to adjust the engine output and rotation.

When the vehicle performs steady running, the target throttle opening degree determining section 15 determines a target vehicle speed V _T based on the accelerator opening α and the vehicle speed V, the target throttle opening degree θ further based on the target vehicle speed V _{T T} has been decided. The control block diagram in this case is shown in FIG. 4, in which the target vehicle speed V _T is determined based on the accelerator opening α, and the target throttle opening θ _T is determined by the I-PD control. Then, the feedback control amount obtained from the target vehicle speed V _T and the current vehicle speed is corrected with a correction value obtained from the degree of change of the current vehicle speed V. The control equation expressing the target throttle opening θ _T in that case is shown in the following equation (4). Note that G ₄ , G ₅ , and G ₆ are constants representing integral gain, proportional gain, and derivative gain, respectively.

θ _T = G ₄ ∫ (V _T −V) dt −G ₅ V −G ₆ V ′ (4) Since it is necessary to control this equation (4) in time units, the value differentiated with respect to time is obtained. Therefore, if θ _T is differentiated, θ _T ′ = G ₄ (V _T −V) −G ₅ V ′ −G ₆ V ″ (5) Here, this vehicle speed deviation V _T −V = ENV Assuming that the vehicle speed in the previous control cycle is V1 and the vehicle speed in the control cycle two times before is V2, θ _T ′ = G ₄ * ENV−G ₅ * (V−V1) −G ₆ * {(V-V1) - (V1-V2)} = G 4 * ENV-G 5 * (V-V1) -G 6 * (V-2V1 + V
2) (6) As is clear from the above equation, the feedback amount obtained from the target vehicle speed V _T and the current vehicle speed V is corrected by the correction value obtained from the degree of change of the current vehicle speed V. Even if the vehicle is affected by a disturbance such as a change in resistance, the variation in the time required to reach the target vehicle speed V _T is eliminated, and a stable driving feeling is obtained.

FIG. 5 is a flowchart showing an example of the main program executed by the control unit 5. It should be noted that this embodiment shows the case where an α- _VT map that differs depending on the gear position is used. First, in step 101, the system is initialized, and in the next step 102, interrupt permission processing is performed. Selecting alpha-V _T map by gear shift position of the transmission 3 in the next step 103. As shown in FIG. 6, this α-V _T map shows the relationship between the accelerator opening α and the target vehicle speed V _T, and there are five different speed gains depending on the first to fifth speed gear ratios. It is represented by the curves A _{1 to} A ₅ . Therefore, in step 103, the five curves A _{1 to} A _{5 are}
Select one of the following according to the gear shift position, and then
At 104, the selected curve is searched for the target speed V _T corresponding to the accelerator opening α. And the next step
At 105, feedback control (IPD control) of the vehicle speed V as shown in FIG. 4 is performed to obtain the target throttle opening θ _T , and throttle control (PID control) is performed. As the control formula in this vehicle speed control, the above-mentioned formula (6) is used. That is, ENV ← V _T −V θ _T ← θ _T + G ₄ * ENV−G ₅ * (V−V1) −G ₆ * (V−2V1 + V2) V1 ← V V2 ← V1 For the next calculation, This vehicle speed V is the previous vehicle speed
The previous vehicle speed V1 is memory-shifted to V1 to the vehicle speed V2 two times before.

FIG. 7 shows the flow of an interrupt program for determining the manipulated variable of the throttle actuator. This program is 10
It is executed every msec.

First, in step 51, interrupts are disabled, and next step
At 52, the accelerator opening α, the throttle opening θ, and the gear position vehicle speed V are read. Then in step 53, the DC of FIG.
Operation amount of the throttle actuator corresponding to the motor 9
The MN is calculated using the above-mentioned equation (3) (PID control).
That is, EN ← θ _T − θ MN ← MN + G ₀ * {G ₁ * (EN-EN1) + G ₂ * EN + G ₃ * (EN-2 * EN1 + EN2)} EN1 ← EN EN2 ← EN1 Note that G ₀ is the entire system. Is a constant representing the control gain of, and is normally set to G ₀ = 1. Also, for the next calculation, the current throttle opening deviation EN is set to the previous throttle opening deviation EN1.
The previous throttle opening deviation EN1 is memory-shifted to the previous throttle opening deviation EN2. Next step 5
In step 4, the manipulated variable MN calculated in step 53 is output to the actuator. In this embodiment, the actuator is
Since it is a DC motor, the manipulated variable MN is converted into a voltage by the D / A converter and output. Then, in step 55, the interrupt is permitted and the interrupt program is terminated.

Next, when the vehicle accelerates, the target throttle opening degree determination unit 15 determines the target acceleration g _T based on the accelerator opening α and the vehicle speed V, and further determines the target throttle opening θ _T by PI-PD control. The block diagram of the control in this case, which is determined, is shown in FIG. The throttle control based on the target throttle opening θ _T is the same PI as in Fig. 3.
D control. A control equation representing the target throttle opening θ _T in such acceleration control is shown in the following equation (7). It should be noted that G ₇ , G ₈ , G ₉ , and G ₁₀ are constants representing proportional gain, integral gain, proportional gain, and derivative gain, respectively.

θ _T = G ₇ (g _T −g) + G ₈ ∫ (g _T −g) dt −G ₉ g−G ₁₀ g ′ (7) Since it is necessary to control this equation (7) in time units. , Θ
By differentiating the _{T θ T '= G 7 (} g T -g)' + G 8 (g T -g) -G 9 g'-G 10 g "...... here at this time (8) acceleration deviation g _T - If g = ENG and the acceleration in the previous control cycle is G1, and the acceleration in the control cycle before the last is G2, then from equation (8), θ _T ′ = G ₇ * (ENG-ENG1) + G ₈ * ENG − _{G 9 * (G-G1)} -G 10 * {(G-G1) - (G1-G2)} = G 7 * (ENG-ENG1) + G 8 * ENG-G 9 * (G-G1) -G 10 * (G-2G1 + G2) (9) Such PI-PD control has an intermediate property between PID control and I-PD control, and is superior in stability to PID control and I in response. because outperforms -PD control can be reliably achieved acceleration requested by the driver. in this case, to improve the responsiveness by increasing the control constant G ₇ representing the proportional gain in the expression (9) Can Alternatively, the vehicle speed control system may be replaced by a PI-PD control system instead of the I-PD control, in which case the control constant representing the proportional gain is reduced and the control constant representing the integral gain is increased. It is possible to balance responsiveness and stability.

In the above embodiment, the throttle valve is used as the adjusting means for adjusting the engine output in the Otto cycle engine in which the intake air amount, that is, the output is adjusted by the throttle valve. However, the output adjusting means in the present invention is not limited to the throttle valve as in the above-mentioned embodiment, and the point is that it is only necessary to change and control a factor that greatly contributes to the engine output. Depends on For example, in the case of a diesel engine whose output basically changes depending on the amount of fuel injected into the cylinder, the control device for the fuel injection amount may be used as the output adjusting means.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an engine control device according to the present invention, FIG. 2 is a basic operation explanatory diagram of the control system according to the present invention, FIG. 3 is a block diagram of a throttle control system, and FIG. 4 is a vehicle speed control system. 5 is a block diagram of FIG. 5, FIG. 5 is a flowchart of a main program for vehicle speed control, and FIG.
FIG. 7 is a map showing the relationship of the target vehicle speed V _T with respect to the accelerator opening α, FIG. 7 is a flowchart of an interrupt program for determining the control amount of the throttle actuator, and FIG. 8 is a block diagram of the acceleration control system. 1 ... Engine, 2 ... Clutch 3 ... Transmission, 4 ... Throttle valve 5 ... Control unit 6 ... Throttle opening sensor 7 ... Vehicle speed sensor 8 ... Clutch stroke sensor 9 ... DC motor

Front Page Continuation (72) Inventor Kazutoshi Nobumoto 3-1, Shinchi Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) Reference JP-A 63-22734 (JP, A) JP-A 61-81235 ( JP, A) JP-A-55-91736 (JP, A) Actually developed 51-397 (JP, U) Actually published 50-41439 (JP, Y1)

Claims (1)

[Claims] 1. An engine control device for determining a target vehicle speed based on an accelerator operation amount and controlling an engine output so as to obtain the target vehicle speed, wherein a feedback control amount obtained from the target vehicle speed and the current vehicle speed. The engine control device is provided with a means for correcting the above with a correction value obtained from the degree of change of the current vehicle speed.