JPH07102785B2 - 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 improvement of a control device for an engine mounted on an automobile, in particular, a control mode of an engine output adjusting means is switched according to a driving state of the vehicle.

(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, there is known a throttle control device in which the throttle valve is electrically feedback-controlled with a predetermined characteristic with respect to the depression amount of the accelerator pedal.

By the way, considering the relationship between the engine driving force and the traveling resistance when the vehicle travels at a constant speed with reference to FIG. 11, when the vehicle travels at the speed V ₁ , the engine driving force and the traveling load are Since and are in an equilibrium state, the curve A ₁ showing the engine driving force characteristic and the curve B ₁ showing the traveling load characteristic intersect at the speed V ₁ . At this time, the traveling load by a change in road gradient varies, the traveling load characteristics for speed if the curve B ₂ is to maintain the speed V ₁ from become V ₂ drops operates the accelerator pedal The throttle valve must be opened to change the engine driving force characteristic to curve A ₂ . That is, in order to drive the vehicle at a constant speed, the accelerator pedal has to be operated in accordance with the fluctuation of the running load, which is troublesome.

Therefore, as disclosed in, for example, Japanese Patent Application Laid-Open No. 60-111029, there has been proposed an engine control device capable of running at a constant vehicle speed without operating the accelerator pedal according to the change in running load. However, such vehicle speed control has a drawback that the driver feels uncomfortable at the time of starting or accelerating. That is, since the vehicle speed is zero at the time of starting, the throttle valve is controlled with a relatively large opening when the accelerator is operated to start.
Until the clutch is engaged, the engine speed will increase rapidly and the driver will feel uncomfortable. On the other hand, at the time of acceleration, if the accelerator operation amount is constant, the speed is controlled to be the same regardless of the degree of change of the accelerator, so that it is not possible to obtain acceleration performance that matches the driver's will.

(Object of the Invention) In view of the above-mentioned circumstances, an object of the present invention is to provide an engine control device in which an optimum control characteristic is automatically selected in accordance with a running state of a vehicle.

(Structure of the Invention) In the engine control device according to the present invention, a control amount of a means for adjusting the output of the engine such as a throttle valve in a gasoline engine or a fuel injection valve and a governor in a diesel engine is based on the accelerator operation amount. First to directly obtain and control the adjusting means
And a second control means for determining the target vehicle speed based on the accelerator operation amount and controlling the adjusting means so as to obtain this target vehicle speed. Normally, the first control means is operated. It is characterized in that the first and second control means are selectively operated according to a driving state of the vehicle so as to operate the second control means during steady running of the vehicle.

(Effects of the Invention) According to the present invention, it is possible to secure stability during steady running without impairing startability and acceleration.

(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. .

In the present embodiment, the target throttle opening θ _T is determined based on the accelerator operation amount, and the throttle valve 4 is controlled so as to obtain this target throttle opening θ _T, and the accelerator operation amount. A target vehicle speed V _T is determined based on the above, and two control systems, a vehicle speed control system in which the throttle valve 4 is controlled so as to obtain this target vehicle speed V _T, are selectively switched depending on the operating state of the vehicle. However, prior to the description of the control flow executed by the control unit 5 in FIG. 1, the outline of each control system will be described first.

FIG. 2 is a diagram for explaining the basic operation of the throttle control system. When the driver depresses the accelerator pedal 11, the accelerator opening signal generator 12 detects the accelerator opening α, and the accelerator opening α Generates a signal corresponding to.
Further, the information detection unit 13 detects the engine state of the vehicle, the gear position, etc., and generates a signal indicating those states. The control unit 14 corresponding to the control unit 5 in FIG. 1 controls the gain characteristic control operation for controlling the gain characteristic of the throttle opening f (α) which is predetermined corresponding to the accelerator opening α, and the accelerator opening α Throttle opening f
A phase characteristic control operation of feedback controlling the phase (response speed) of (α) is performed. The gain characteristic control operation, variably controlled by a signal from the information detector 13 the gains of the throttle opening f (alpha) with respect to the accelerator opening degree alpha, determines a target throttle opening theta _T. In this case, when the gain is increased, a powerful driving feeling is obtained, while when the gain is decreased, an economical driving feeling is obtained. Further, in the phase characteristic control operation, the throttle opening f with respect to the accelerator opening α
The phase of (α) is variably controlled by a signal from the information detection unit 13. A servo drive unit 15 corresponding to the DC motor 9 in FIG. 1 drives the throttle valve 4 by a control signal output from the control unit 14. The throttle opening signal generator 17 corresponding to the throttle opening sensor 6 in FIG. 1 detects the actual throttle opening θ and generates a signal corresponding to this, and outputs the signal corresponding to the target accelerator opening θ _T and the actual throttle opening θ _T. The value of θ is fed back to the control unit 14 so that the opening θ coincides. The control operation performed by the control unit 14 in this case is PID control (proportional operation + integral operation + differential operation) with a fast response speed, and its block diagram in FIG. 3 is shown. 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 a proportional gain, an integral gain, and a derivative gain, respectively.

θ _T = G ₁ (θ _T −θ) + G ₂ ∫ (θ _T −θ) dt + G ₃ (θ _T −θ) ′ …… (1) 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 Therefore, the output and rotation of the engine can be easily adjusted, and it is easy to fit in and gives the driver a sense of security. In addition, since PID control with good responsiveness is performed, it is suitable for starting, shifting, and slight acceleration.

Next, FIG. 4 shows a block diagram of the vehicle speed control system,
In this case, the target vehicle speed V _T is determined based on the accelerator opening α, and the target throttle opening θ _{T is} further determined by the I-PD control.
Has been decided. The throttle control based on the target throttle opening θ _T is the same PID control as in FIG. A control equation representing the target throttle opening θ _T in such vehicle speed control is shown in the following equation (4). Note that G ₄ , G ₅ , and G ₆ represent an integral gain, a proportional gain, and a derivative gain, respectively.

_{θ T = G 4 ∫ (V} T -V) dt-G 5 V-G 6 V '...... (4) if differentiated _{θ T θ T' = G 4} (V T -V) -G 5 V ' −G ₆ V ″ (5) Here, the current vehicle speed deviation V _T −V = ENV is set, the vehicle speed deviation in the previous control cycle is ENV1, and the current vehicle speed is V
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 * (V2 * V1 + V2) ...... (6) such I-PD The characteristic of the control is that the response speed is inferior to that of the PID control, but the response speed is stable with respect to the disturbance, and it is suitable for the control of the phase characteristic. Therefore, even if the vehicle is affected by a disturbance such as running resistance, variations in the time required to reach the target vehicle speed are eliminated, and a stable driving feeling can be obtained.

The conditions for switching from throttle control to vehicle speed control are: (1) When the vehicle is in a steady running state (when the accelerator is held at a substantially constant state) (2) A slight accelerator return operation after acceleration was performed. When (3) The transmission is switched to a high gear position, etc. On the other hand, the prohibition conditions for vehicle speed control are: (1) When the vehicle speed is below a predetermined value (for example, 10km / hour) (2) When the clutch is disengaged or half-clutched (3) When the gear position of the transmission is in the neutral or reverse position (4) When operating the steering wheel (5) When operating the brake (brake switch ON) (6) When the difference between the target vehicle speed V _T and the actual vehicle speed V is large (the target throttle opening θ _T is outside the range of 0 to 100). It comes out and feels bad.) (7) When the driver turns on the vehicle speed control prohibition switch.

FIG. 5 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, accelerator opening α, throttle opening θ, clutch stroke, gear position, brake switch ON / OFF
Read off, vehicle speed V, steering angle S. Then step 53
Then, the manipulated variable MN of the throttle actuator corresponding to the DC motor 9 in FIG. 1 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. Represents the control gain of, usually G ₀ =
Set to 1. Further, for the next calculation, the previous throttle opening deviation EN1 is memory-shifted to EN, and the throttle opening deviation EN2 two times before is memory-shifted to the previous throttle opening deviation EN1. Next, in step 54, the manipulated variable MN calculated in step 53 is output to the actuator. In this embodiment, since the actuator is a DC motor, the manipulated variable MN is D /
Converted to voltage by A converter and output. Then, in step 55, the interrupt is permitted and the interrupt program is terminated.

FIG. 6 is a flow chart showing an example of a main program executed by the control unit 5, which incorporates the above-mentioned switching condition (3) and prohibiting conditions (1) to (5) and (7) to implement throttle control and vehicle speed control. 7 shows a control flow in the case of switching the vehicle according to the driving state of the vehicle and selectively activating the vehicle. That is, first, in step 101, the system is initialized, and in the next step 102, interrupt permission processing is performed. In the next step 103, it is determined whether the vehicle speed control prohibition switch is ON or OFF. If it is OFF, the process proceeds to the next step 104, and if it is ON, the process proceeds to step 111 and the target throttle opening θ is set by the throttle control. Set _T. In step 104, it is determined whether or not the vehicle speed V is equal to or lower than the predetermined value ε ₁ , and if the result of this determination is NO, the process proceeds to the next step 105, and if YES, the process proceeds to throttle control in step 111. In step 105, the clutch stroke is determined, and if the clutch is in the engaged state, the process proceeds to the next step 106, and if the clutch is in the disengaged state or the half-clutch state, the process proceeds to the throttle control in step 111. step 1
In 06, it is determined whether or not the steering angle S of the steering wheel is larger than a predetermined value ε _{2, and} if the result of the determination is NO, then the next step 10
7. If YES, proceed to step 111 Throttle control. In step 107, it is determined whether or not the brake is ON. If NO, the process proceeds to the next step 108, and if YES, the process proceeds to throttle control in step 111. In step 108, the gear position of the transmission is determined, and the gear position is 3
Step 109 only in case of any of the fourth speed, the fifth speed and the fifth speed
Go to and set θ _T by controlling the vehicle speed. Then, in the next step 110, it is determined whether or not θ _T is within the range between 0 and 100. If the determination result is YES, the process returns to step 103, and if NO, the throttle control in step 111 is performed. Move.

By the way, in the throttle control in step 111 of FIG. 6, the map as shown in FIG. 7 is read to set the target throttle opening θ _T directly from the throttle opening α, and the PID control as shown in FIG. Although the operation amount of the throttle actuator is determined by performing the above, in the vehicle speed control of step 109, the target throttle opening degree is determined by the control flow as shown in FIG. Then, in this case, the target vehicle speed V _T is obtained by the α-V _T map as shown in FIG. 9 in which the target vehicle speed V _T for constant vehicle speed control is made to correspond to the accelerator opening α. That is, in step 141 of FIG. 8, the target vehicle speed V _T is obtained from the α-V _T map, and in the next step 142, feedback control (I-PD control) of the vehicle speed V as shown in FIG. 4 is performed. , Target throttle opening θ _T is calculated, and throttle control (PID control is performed. The control formula in this vehicle speed control uses the formula (6) above. That is, ENV ← V _T −V θ _T ← θ _T + G ₄ * ENV-G ₅ * (V-V1) -G ₆ * (V-2 * V1 + V2) V2 ← V1 V1 ← V For the next calculation, change the previous vehicle speed V1 to the vehicle speed V2 two times before and this vehicle speed. V is memory-shifted to the previous vehicle speed V1, and the vehicle speed V and the target vehicle speed are changed when the vehicle speed control is changed.
When V _T is significantly different, the vehicle speed V is corrected so that it passes on the α-V _T map. Further control gains G _{4 to} G ₆
May be reduced to delay responsiveness.

Further, in step 142 of FIG. 8, α-V of FIG.
Instead of _T map, by using the alpha-V _T map as shown in FIG. 10 with a reduced speed gain in a specific speed range, it is possible to further improve the control characteristic in the vehicle speed control. That is, at the vehicle speed corresponding to the average vehicle speed range, the passenger vehicle speed range, or the accelerator opening at the time of entering the vehicle speed control, the speed gain can be reduced to prevent hunting in the vehicle speed range.

By performing the vehicle speed control as described above, it is possible to correct the effects of weather conditions, road surface conditions, and vehicle conditions when a constant vehicle speed is required, so that the vehicle speed can be stabilized according to the accelerator opening regardless of these conditions. It becomes possible to drive. Moreover, in the present invention, since the throttle control and the vehicle speed control are switched according to the driving state of the vehicle, it is possible to secure the traveling stability during steady traveling without impairing the starting performance and the acceleration performance.

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 an operation explanatory diagram of a throttle control system,
FIG. 3 is a block diagram of the throttle control system, and FIG.
Fig. 5 is a block diagram of the vehicle speed control system, Fig. 5 is a flowchart of an interrupt program for determining the control amount of the throttle actuator, Fig. 6 is a flowchart of the main program, and Fig. 7 is a target throttle opening θ _{T with} respect to the accelerator opening. 8 is a flowchart showing the relationship of the vehicle speed control, FIGS. 9 and 10 are maps showing the relationship of the target vehicle speed V _T with respect to the accelerator opening α, and FIG. 11 is the constant speed running by the throttle control. 5 is a graph showing an engine driving force and a traveling load with respect to a vehicle speed in a case. 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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazutoshi Nobumoto 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP-A-60-176830 (JP, A) JP-A-61 -81235 (JP, A) JP-A-61-171618 (JP, A)

Claims (1)

[Claims] 1. A first control means for directly determining a control amount of an adjusting means for adjusting an engine output based on an accelerator operation amount to control the adjusting means, and a target vehicle speed based on the accelerator operation amount. And a second control means for controlling the adjusting means so as to obtain this target vehicle speed,
Normally, the first control means is operated, and the first control means is operated so as to operate the second control means when the vehicle is traveling steadily.
An engine control device comprising: an operating unit that selectively operates the second control unit according to a driving state of the vehicle.