JPS6316154A - Engine control device - Google Patents

Abstract

PURPOSE:To efficiently prevent an acceleration shock while ensuring the responsiveness of acceleration by making the change in the controlling quantity of an engine output with respect to the operation of an accelerator at the time of shifting from deceleration to acceleration, the smoother the higher is the degree of deceleration. CONSTITUTION:A control part 14 selects one map out of plural maps 15 based on an engine condition from an information detecting part 13. And, the lowering rate K of a throttle gain is set by means of a setting part 16. And, a target accelerator opening, thetaT=(KXf(alpha) corresponding to an accelerator opening alphais obtained. Further, by using one of control gains G0-G4 determined by vehicle condition information from the detecting part 13, a feedback control is carried out by a control part 17. Here, the setting part 16 increases the lowering rate K of the throttle gain at the time of shifting from a decelerating condition to an accelerating condition, in proportion to the degree of deceleration, and removes this lowering rate K at the point of time when a vehicle speed is increased by a set value. Thereby, an acceleration shock at the time of shifting from deceleration to acceleration can be prevented, while ensuring the responsiveness of acceleration at the start of a vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine control device, and particularly to throttle control when a vehicle shifts from deceleration to acceleration.

(Prior Art) In order to improve the driving characteristics of automobiles, various throttle control devices have been proposed in the past in which the throttle valve is electrically feedback-controlled with predetermined characteristics in response to the amount of depression of the accelerator pedal. ing. In such throttle valve control, for example, the one disclosed in Japanese Unexamined Patent Publication No. 10753/1987 prevents acceleration shock by reducing the rate of change in the throttle valve opening when the throttle valve is fully open. be. However, simply performing throttle control in this manner has the disadvantage that the acceleration response when starting is reduced. When an operation is performed to change from deceleration to acceleration, there is a risk of acceleration shock occurring.

Figure 11 shows changes in accelerator opening α, throttle opening θ, vehicle speed V, and acceleration g with respect to time (1) when the vehicle changes from deceleration to acceleration, and shows the change in time (1) when the vehicle changes from deceleration to acceleration.
This shows a state in which an acceleration shock occurs due to acceleration fluctuations near 0. This acceleration shock is of course proportional to the absolute amount of acceleration, but even if the acceleration is the same,
The shock felt by the driver differs depending on the previous engine condition, that is, the degree of deceleration.

(Object of the Invention) In view of the above-mentioned circumstances, the present invention provides an engine control device that ensures acceleration responsiveness at the time of starting while preventing acceleration shock from occurring even when sudden accelerator operation is performed during deceleration. The purpose is to provide

(Structure of the Invention) The present invention includes means for detecting deceleration when a vehicle is decelerating, and the larger the deceleration, the smoother the change in the control amount of engine output in response to accelerator operation when changing from deceleration to acceleration. It is characterized by comprising means.

(Effects of the Invention) According to the present invention, it is possible to effectively prevent acceleration shock when changing from deceleration to acceleration while ensuring acceleration responsiveness in a state where there is not much shock, such as when starting.

(Example) An example of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a system configuration diagram of an engine control device according to the present invention, where l is the engine, 2 is a clutch, 3 is a transmission, 4 is a throttle valve, 5 is a control unit consisting of a microcomputer, and 6 is a throttle opening. The sensors include a vehicle speed sensor 7, an engine rotation speed sensor 8, and a DC motor 9 as an actuator for the throttle valve 4.

The control unit 5 includes an accelerator opening α indicating the amount of depression of the accelerator pedal, and a throttle opening sensor 6.
Throttle opening degree θ from , vehicle speed ■ from vehicle speed sensor 7,
Signals indicating the gear position from the transmission 3, the engine speed Ne from the engine speed sensor 8, etc. are input, and the control unit 5 generates an output signal for driving the DC motor based on these input signals. It is configured to generate the throttle valve 4 and control the throttle valve 4.

FIG. 2 is a diagram illustrating the basic configuration and operation of the throttle control system according to the present invention. When the driver depresses the accelerator pedal 11, the accelerator opening signal generator 12 detects the accelerator opening α. , generates a signal corresponding to this accelerator opening degree α. In addition, the information detection unit 13
detects the vehicle's engine condition, surrounding conditions, etc., and generates signals to alert these conditions. 1st
The control section 14 corresponding to the control unit 5 in the figure is
A plurality of maps 15 that generate a predetermined throttle opening f(α) corresponding to the accelerator opening α are selected by a signal from the information detection unit 13, and a throttle gain reduction rate K (normally 1) a section 16 for setting 1);
It consists of a feedback control section 17 and a control gain determination section 18 that determines control gains 00 to G4 (described later) based on the signal from the information detection section 13. Two operations are performed in this control section 14. That is, one map is selected from the plurality of α-r(α) maps 15,
and a gain characteristic control operation that determines the reduction rate K of the throttle gain and determines the target accelerator opening θa (θ7=to*f(α)), and a feedback control operation that controls the throttle valve 4. In the latter feedback control operation, the control gains G, to G4 of the feedback control section 17 are determined based on the signal from the information detection section 13. This makes the transient response of the throttle opening θ variable. Output from feedback control section 17 (OUT)
is a servo drive section 19 corresponding to the DC motor 9 in FIG.
This servo drive section 19 drives the throttle valve 4. In addition, the throttle opening sensor 6 in FIG.
The throttle opening signal generating section 20 corresponding to the throttle opening signal generating section 20 detects the actual throttle opening degree .theta. and feeds back the value of this .theta. to the feedback control section. Control unit 1 in this case
The control operation performed by No. 4 is PID control (proportional action + integral action element differential action) with a fast response speed. Based on this, the target throttle opening θ7 is determined, and the control formula for determining the target throttle opening θ7 is shown in the fl1 formula below.
are the constants 10G, (θ1−θ)′ −・−−1−, which represent the proportional gain, integral gain, and differential gain, respectively.
-・-・〜・・・・・・(1) Since it is necessary to control this equation (1) in units of time, it is necessary to obtain a value differentiated with respect to time.

Differentiating θi, θT'=GI(θ1-θ)'+G*(θ1-θ)10G,
(θa θ)′ −・−・・・・・・・−・・−−−
−−−(2+Here, the current throttle opening deviation θ7−θ
= EN, the throttle opening deviation in the previous control cycle is ENI, and the throttle opening deviation in the control cycle before the previous control cycle is EN2. From equation (2), θT'
=Gl* (EN-ENI)+G'z'kEN+G,
* ((EN-ENI) - (ENI-EN2)) =GI* (EN-ENI)+G! *EN+Gs* (
EN-2*EN1 +EN2)--m=・--1-・・
(3) In the embodiment of the present invention, the throttle gain is reduced when the vehicle changes from a deceleration state to an acceleration state. The reduction rate of the throttle gain at this time is made proportional to the deceleration, as will be clear from what will be described later. As shown in FIG. 4, the throttle gain reduction is canceled when the vehicle speed increases by the set value Δ■ from the time t0 when deceleration changes to acceleration. As is clear from FIG. 4, this makes it possible to prevent acceleration shock. Or a predetermined time Δt from time t0
The reduction in throttle gain may be canceled after the lapse of time.

Furthermore, as shown in Fig. 5, in the region where the throttle opening is less than 01 near the fully open throttle valve, acceleration shock can be prevented even if the control gain G0 of the entire PID control system is made small to suppress the speed of change of the throttle valve. It can be prevented. This case has the advantage of preventing deceleration shock when the accelerator is suddenly turned off.

Next, FIG. 6 shows the flow of the main program for throttle control performed by the control unit 5 in the present invention. First, in step 31, the system is initialized and the deceleration flag is set.

Next, in step 32, an interrupt permission process is performed, and then in step 33, the target throttle opening θa relative to the accelerator opening α is determined.

FIG. 7 shows the flow of an interrupt program that determines the amount of operation of the throttle actuator. This interrupt program is executed every 3Qmsec.

First, in step 51, interrupt prohibition processing is performed, and in the next step 52, the accelerator opening degree α, the throttle opening degree θ
, reads the vehicle speed V, and calculates the acceleration g. It also reads the engine speed Ne and gear position. Next, in step 53, it is determined whether the throttle opening θ is smaller than a predetermined opening θ near the fully closed throttle valve. If the judgment result is NO, the control gain G0 of the entire system is set to 1 in step 54, and the process proceeds to the next step 56. If the judgment result in step 53 is YES, that is, when the throttle opening θ is near full open, sets the control gain G0 to Gk (however, 0<Gm<1) and proceeds to step 56. In step 56, the DC
The operation amount MN of the throttle actuator corresponding to the motor 9 is calculated using the above-mentioned equation (3) (PID control). That is, EN←θ7−θ M N = M N + G o *(G, * (
E N E N 1 ) + Gt * EN + Gs” (EN 2'kEN1 + EN2) IENI←
EN EN2←ENI Note that Go is a constant that determines the control gain of the entire system, and is normally set to G0=1. Also, for the next calculation, the current throttle opening deviation EN is converted to the previous throttle opening UA.
For the differences E and N1, the previous throttle opening deviation ENI is memory-shifted to the two previous throttle opening deviation EN2. Next, the process proceeds to step 57, where the amount of intelligence MN calculated in step 56 is output to the actuator. In this embodiment, the actuator is a DC motor, so
Operation i1MN is converted into voltage by a D/A converter and output. Then, in step 58, interrupts are enabled and this interrupt program is ended.

FIG. 8 shows an example of a control flow for determining the target throttle opening θ7 when changing from deceleration to acceleration. First, in step 101, it is determined whether the accelerator opening α is zero. If this determination result is zero, it means that the engine is in an idling state or the vehicle is decelerating, so the process moves to step 102 and the engine speed N
It is determined whether e is larger than the idle rotation speed. If this judgment result is YES, it is decelerating, so step 1
At step 03, a deceleration flag is set, at step 104 the vehicle speed at that time is memorized, and at step 105 the acceleration g(
In this case, since we are decelerating, g is a negative value), and in the next step, the throttle gain reduction rate K is calculated by 1.
Then, the process moves to step 107. In step 107, one map is selected from a plurality of maps showing the relationship between the accelerator opening degree α and the throttle opening degree f(α) as shown in FIG. 9, for example. In Fig. 9, straight line A indicates that the gear position of the transmission 3 in Fig. 1 is neutral, reverse, 1 to 3.
Accelerator opening and throttle opening f(
.alpha.), and curves B and C show the maps when the gear positions are at the 4th and 5th speed positions, respectively.

When the gear position is in 4th or 5th gear,
Since the driving force of the tires is small and the running abrasion is large, the gain of the throttle opening f(α) with respect to the accelerator opening α is increased. Next, in step 108, the value of the throttle opening f(α) with respect to the accelerator opening is determined using the map selected in step 107, and in step 10
9, this accelerator opening f(α) is multiplied by the throttle gain reduction rate K (1 in this case) to set the target throttle opening to 0.
Decide on the ding.

Next, if it is detected in step 101 that α is not zero, the process proceeds to step 110, where it is determined whether the deceleration flag is set. If the deceleration flag is not set, it is determined that it is time to start, and the process moves to step 106; however, if the determination result in step 110 is YES, it is determined that the deceleration has changed to acceleration, and the process proceeds to step 111.
It is determined whether the vehicle speed ■ has increased by a predetermined speed Δ■ from the previously stored vehicle speed vI<vehicle speed when changing from H speed to acceleration). Then, while the vehicle speed V has not reached vl +ΔV, the throttle gain reduction rate K is determined in step 112.
are set based on FIG. Figure 10 shows the acceleration g
+ and the throttle gain reduction rate K. If g1≧0, then = 1, but if g+ <Q, K is g.

is set to be inversely proportional to the absolute value of Then, in step 109 after going through steps 107 and 108 described above, the target throttle opening θ7 is determined from θ,=*f(α), and in this case, since O<K<1, the target throttle opening θ, is reduced than otherwise and therefore the fourth
As is clear from the figure, the opening speed of the throttle valve 4 is smaller than in the case where 2=1. If it is detected in step 111 that the vehicle speed V has exceeded vl +ΔV, the flow moves to step 113, where the deceleration flag is set to -1, and the throttle gain reduction is canceled at step 106.

As is clear from the above explanation, in this embodiment, means is provided to detect the deceleration when the vehicle decelerates, and the larger the deceleration, the more the throttle valve is opened in response to the accelerator operation when changing from deceleration to acceleration. Since the speed is controlled to be low, acceleration shock when changing from deceleration to acceleration can be effectively prevented.

The above embodiment uses a throttle gain as a means for controlling engine output in an automatic cycle engine in which the intake air amount, that is, output is adjusted by a throttle valve. However, the output adjustment means in the present invention is not limited to the throttle valve as in the above embodiment, but may be any means that changes and controls factors that significantly contribute to engine output. For example, in the case of a diesel engine whose output basically changes depending on the amount of fuel injected into the cylinder, the fuel injection amount control device may be used as the output adjustment means.

[Brief explanation of the drawing]

Fig. 1 is a system configuration diagram of an engine control device according to the present invention, Fig. 2 is an explanatory diagram of the configuration and operation of a throttle control system, Fig. 3 is a block diagram of the throttle control system, and Figs. 4 and 5 are Graphs explaining the present invention in detail, Figure 6 is a flowchart of the main program, Figure 7 is a flowchart of an interrupt program that determines the control amount of the throttle actuator, and Figure 8 is the target throttle opening when changing from deceleration to acceleration. The flowchart for determining θ7, FIG. 9 is a map showing the relationship between the throttle opening f(α) and the accelerator opening α.
FIG. 0 is a map showing the relationship between the reduction rate of throttle gain and acceleration/deceleration, and FIG. 11 is a graph illustrating a state in which an acceleration shock occurs in a conventional device. 1 - Engine 2 - Clutch 3 - Transmission 4 - Throttle valve 5 - Control unit 6 - Throttle opening sensor 7 - Vehicle speed sensor 8 - Engine speed sensor 9 - D C motor

Claims (1)

[Claims] In an engine control device that controls engine output based on an accelerator operation amount, there is provided a means for detecting deceleration when a vehicle is decelerating, and the accelerator operation when changing from deceleration to acceleration as the deceleration increases. 1. A control device for an engine, comprising: means for smoothing changes in a control amount of engine output relative to the engine output.