JPS6325355A - Control device for engine - Google Patents

Abstract

PURPOSE:To enable production of running feeling, desired by a driver, in all running states whatever, by a method wherein an optimum control means is selected according to the running state of a vehicle for actuation. CONSTITUTION:In a control unit 5, a target throttle valve opening is decided based on an acceleration control amount by means of a first control means, and a throttle valve 4 is controlled so as to provide the target throttle opening. A target car speed is decided based on an accel control amount by means of a second control means, and the throttle valve 4 is controlled so as to provide the target car speed. Further, target acceleration is decided based on an accel control amount by means of a third control means, and the throttle valve 4 is controlled so as to provide the target acceleration. In selection of a control system, signals from a clutch stroke sensor 8, a sensor for the gear position of a transmission 3, a throttle opening sensor 6, and a car speed sensor 7 are used.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention converts the amount of accelerator operation into an amount of electricity, and controls engine output adjustment means such as a throttle valve in accordance with this amount of electricity. The present invention relates to an improvement in a control device for an engine installed in an automobile, and in particular, the control mode of an engine output adjusting means is changed according to the driving state of the vehicle.

(Prior art) In general automobiles, the accelerator pedal and the throttle valve are mechanically connected, and the opening degree of the throttle valve is uniquely determined by the amount of depression of the accelerator pedal. It has been impossible to change the relationship between the opening degree of the throttle valve and the opening degree of the throttle valve depending on the driving state of the vehicle.

Therefore, various throttle control methods have been proposed in the past in which the throttle valve is electrically controlled to have predetermined characteristics with respect to the amount of depression of the accelerator pedal. Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 60-111029, it is also known that when controlling the throttle valve in response to the amount of depression of the accelerator pedal, the vehicle speed is controlled by considering the accelerator original ■ as the vehicle speed. It is being

However, it is difficult to adapt the individual throttle control or vehicle speed control to the various driving conditions of the vehicle, and it is difficult to obtain the driving feeling desired by the driver under various conditions. Met. In other words, in a system that determines the target vehicle speed based on the amount of operation of the accelerator pedal, although the vehicle speed stability during steady driving is improved, it is not possible to obtain a sufficient engine output response to the operation of the accelerator pedal. A system that determines the throttle opening degree based on the operating amount of The problem arises that people need to make their own adjustments.

(Object of the Invention) An object of the present invention is to automatically select optimal control characteristics depending on the driving condition of the vehicle.

(Structure of the Invention) The engine control device according to the present invention controls the control amount of an adjustment 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, based on an accelerator operation amount. a first control means that directly determines the target vehicle speed and controls the adjustment means; a second control means that determines a target vehicle speed based on the accelerator operation amount and controls the adjustment means so that the target vehicle speed is obtained; At least two of the three control means are provided, including a third control means that determines a target acceleration based on the accelerator operation amount and controls the adjustment means so that the target acceleration is obtained, and each of these control means 21
The present invention is characterized in that the means is selectively operated by switching the means according to the driving condition of the vehicle.

(Effects of the Invention) According to the present invention, since the optimum control means is selected and operated according to the driving condition of the vehicle, the driving sensation desired by the driver can be obtained in any driving condition.

(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, in which 1 is an 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. sensor, 7 is a vehicle speed sensor, 8 is a clutch stroke sensor,
9 is a DC as an actuator for the throttle valve 4
It's a motor. The control unit 5 receives the accelerator opening α indicating the amount of depression of the accelerator pedal, the throttle opening θ from the throttle opening sensor 6, and the vehicle speed sensor 7.
, the clutch stroke from the clutch stroke sensor 8, the gear position from the shift a3, and other signals indicating the steering angle, brake drift, etc., and the control unit 5 controls the DC control based on these input signals. The throttle valve 4 is configured to generate an output signal for driving the motor to control the throttle valve 4.

This embodiment uses a throttle control system that determines a target throttle opening θ7 based on the accelerator operation amount and controls the throttle valve 4 so as to obtain this target throttle opening θ7, and a throttle control system that determines the target throttle opening θ7 based on the accelerator operation amount. Determine the target vehicle speed V? a multiplex control system that controls the throttle valve 4 so as to obtain the desired acceleration, and an acceleration control system that determines a target acceleration g7 based on the amount of accelerator operation and controls the throttle valve 4 so that the target acceleration g7 is obtained. 3 with the system
The vehicle is configured to switch between two control systems and selectively operate them depending on the driving state of the vehicle.Before explaining the control flow executed by the control unit 5 in FIG. 1, we will first give an overview of each control system. I will explain about it.

FIG. 2 is a diagram illustrating the basic operation of the throttle control system. When the driver depresses the accelerator pedal 11, the accelerator opening signal generating section 12 detects the accelerator opening α. Generate a signal corresponding to α. Further, the information detection section 13 detects the engine condition, gear position, etc. of the vehicle, and generates a signal indicating these conditions.

Control unit 1 corresponding to control unit 7 5 in FIG.
4 is a gain characteristic control operation that controls the gain characteristic of the throttle opening r (α), which is predetermined corresponding to the accelerator opening α, and the throttle opening f relative to the accelerator opening α.
In the gain characteristic control operation, which performs the phase characteristic control operation that feedback-controls the phase (response speed) of (α),
The gain of the throttle opening degree r (α) with respect to the accelerator opening degree α is variably controlled by the signal from the information detection unit 13, and the target throttle opening degree θ7 is determined. In this case, increasing the gain provides a powerful driving feeling, while decreasing the gain provides an economical driving feeling. In the phase characteristic control operation, the phase of the throttle opening f (α) with respect to the accelerator opening α is variably controlled by a signal from the information detection unit 13 . A servo drive unit 15, which corresponds to the DC motor 9 in FIG. 1, drives the throttle valve 4 in response to a control signal output from the control unit 14. A throttle opening signal generating section 17 corresponding to the throttle opening sensor 6 in FIG. The value of θ is fed back to the control unit 14 so that the opening degree θ matches the opening degree θ. Control unit 1 in this case
Is the control operation performed by 4 a PID system with fast response speed? D
(Proportional action + Integral action + Differential action), whose block diagram is shown in Fig. 3. In this throttle control, the target throttle opening θ7 is determined based on the accelerator opening α. The control equation for controlling the opening degree θ7 is shown in equation 10 below, where G+, Gz, and G3 are a proportional gain, an integral gain, and a differential gain, respectively.

10G, (θ1-θ)' −−−−−・−・−−−
---(If we differentiate 1107, θt'=a, Cθ7-〇)'+G2(θ,-〇)0G,
(θ7−θ)′ −・・・−−1−−−−・・・・
−−−+21 Here, the current throttle angle deviation θ ar 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), θv'
=G+*(EN ENl)”G**EN+G, *
((EN-ENI)-(ENI-EN2)1 =G, *(EN-ENI)+C,'kEN4-Q,*
(F, N-2*EN1+EN2)-・-・-・・～・
−・−・−(3) In this type of throttle control, the movement of the throttle valve corresponds to the accelerator opening, making it easy to adjust engine output and rotation, and easy to get used to (for the driver). It gives a sense of security.Also, since it uses PID control with good responsiveness, it is suitable for starting, shifting gears, and slight acceleration.

Next, Figure 4 shows a block diagram of the vehicle speed control system.
In this case, the target vehicle speed ■7 is determined based on the accelerator opening degree α, and the target throttle opening degree θ7 is further determined by 1-PD control. The throttle control based on the target throttle opening θ7 is PID control similar to that shown in FIG.

A control equation for determining the target throttle opening θ7 in such vehicle speed control is shown in equation (4) below. Furthermore, G4,
G3 and G represent integral gain, proportional gain, and differential gain, respectively.

-Gh(V, -V)' ・−・−−−−−−・
-...(4) If we differentiate G7, θT' -Ca (VT-V)-Gs (VT-V)'
-06 (V, -v)# ・・−・−−−−1・・−
(5) Here, the current vehicle speed deviation V r −V = E N
V, and the vehicle speed deviation in the previous control cycle is E.
NV l, the vehicle speed deviation in the control cycle before the previous time is F
, N V 2, then from equation (5), θT' = Ga * F, N V Gs * (
E N V E N Vl)-G, *I (ENV
-ENV 1) - (ENVI - ENV2) 1 = Ga * E N V Gs * (EN V -
E N Vl)G a ” (E N V 2 ”
E N V 1+ E N V 2 ) -----
-+61 What are the characteristics of this kind of I-PD control, PID system?
Although the response speed is inferior to ffU, the response speed is stable against disturbances and is suitable for controlling phase characteristics. Therefore, even if affected by external disturbances such as running resistance, variations in the time it takes to reach the target vehicle speed are eliminated.
Provides a stable running feeling.

Furthermore, FIG. 5 shows a block diagram of the acceleration control system, in which the target acceleration g is determined based on the accelerator opening α, and the target throttle opening θ7 is further determined by Pl-PD control. . Target throttle opening θ
, the throttle control based on PIDI is similar to that shown in Figure 3.
I? It is 11.

In such acceleration control, the target throttle opening θ,
The control equation for controlling this is shown in equation (7) below. In addition, G,
,,G3,G9,G1. denote proportional gain, integral gain, proportional gain, and differential gain, respectively.

Go (gy g) Go. (gt g)'---
～−−−−・・・−・−・−−−−−+71If we differentiate θ7, θr' = Gq (gt g)' +Ga (gr
g) Gq(gr g)' Go. (gt-g)
'・−・・−・−・−・−−−１−・−・(8) Here, the current acceleration deviation g, -g=ENG, the acceleration deviation in the previous control cycle is ENG 1, and the acceleration deviation in the previous control cycle is If the acceleration deviation in the control cycle is ENG2, then
From equation (8), θ? '=G1*CENG-ENG1''
)+G@*ENG-Gw*(ENG-ENGl) Go. * ((ENG-ENGI) -(ENGI-ENG2)) Tomi G? * (E N G E N, G 1)
+ G e * E N G-G, *(ENG-EN
Gl) -C,. *CF, NG-2j ENG1 + ENG 2) −・・・・・・−−−−−−
---(g) Such Pl-PD control is performed using PID#+
II Goto [-P D? ! 114B, superior in stability to PID control, and responsive to 1-PD? ! lI? Since it is superior to I, it is possible to reliably achieve the acceleration requested by the driver.

Next, FIG. 6 shows the flow of an interrupt program for determining the amount of operation of the throttle actuator.

This program is executed every 1Qmsec.

First, in step 51, interrupts are prohibited, and in the next step 52, the accelerator opening degree α, throttle opening degree θ, clutch stroke, steering wheel steering angle S, vehicle speed ■, and gear position are read, and the acceleration g is calculated. In 53, the operation 11MN of the throttle actuator corresponding to the first DC motor 9 was described above (calculated using equation 31 (PLD control), that is, EN←θ7−θ MN−MN+Go'k (G, * ( EN-ENI)”
Gz*EN 10Gyu*(EN-2*EN1+EN2) IENI←EN F, N 2-ENI Note that Go is the control gain of the entire system, and usually G
o ” 1. Also, for the next calculation, the previous throttle opening deviation ENI is memory-shifted to EN, and the throttle opening deviation EN2 from the time before last is memory-shifted to the previous throttle opening deviation ENI.

Next, the process proceeds to step 54, where 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 converted into voltage by a D/A converter and output. Then, in step 55, interrupts are enabled and this interrupt program is ended.

FIG. 7 shows a flowchart of the main program executed by the control unit 5, and shows the flowchart of the main program executed by the control unit 5 when the three control systems, the throttle control system, the vehicle speed control system, and the acceleration control system, are switched and selectively operated according to the driving state of the vehicle. Showing control flow.

In FIG. 7, first, in step 101, the system is initialized, and in the next step 102, interrupts are enabled. Next, in step 103, the clutch stroke is determined, and if the clutch is connected, the process proceeds to step 104, and if the clutch is in the disengaged or half-clutch state, the process proceeds to step 105. In step 104, the gear position is determined, and if the gear position is in the 1st to 5th gears for MIT vehicles or the D range for A/T vehicles, the process proceeds to step 106, and the gear position is in the reverse (R) or neutral (N) position. When it is, the process moves to step 105. In step 105, the acceleration control flag (flag g) and the vehicle speed control flag (flag ■) are turned OFF, and step 1
At 07, the target throttle opening θi is set by throttle control.

In step 106, the difference α' between the current accelerator opening α and the previous accelerator opening α1 is calculated, and α is shifted to α for the next calculation.

In the next step 108, the current vehicle speed ■ and the previous vehicle speed ■
, and shift V to V for the next calculation. Next, proceed to step 109, examine the value of α' calculated in step 106, and use α'#O. If so, the process proceeds to the next step 110, and if α'>0, the process proceeds to step 111, where the flag ■ is turned OFF. Also α
'<0, the process moves to step 112 and flags g and V are turned off. In step 110, it is determined whether α-〇, and if the determination result is No, step 1
In step 113, it is determined whether v'-o or not. If the result of the determination is YES, it is determined that the vehicle is in a constant speed running state, and in step 114, the flag (2) is turned on. Next step 1
After turning off the flag ■ in step 11, α is set in step 115.
'>ε1 (1+ is a predetermined value). If the result of the determination is YES, it is determined that the vehicle is in an acceleration state, and the flag g is turned ON in step 116. Furthermore, if the determination result in step 110 is YES and if the determination result in step 113 is NO, step 1
At step 17, turn off the flag ■. Step 112.11
4. After the processing in either 116 or 117 is performed, the flow advances to step 118, where ■〉ε(
ε2 is a predetermined value), and if the determination result is YES, the process proceeds to step 119 and the flag V is turned ON.
If the determination result is YES, in step 120 the target accelerator opening degree θ is determined by vehicle speed control.
Set 7. Further, if the determination result in step 11B or 119 is No, it is determined in step 121 whether or not flag g is ON, and if the determination result is YES, in step 122 the target accelerator opening is controlled by acceleration control. Set θ7. If the determination result in step 121 is No, the process moves to step 107 and the target accelerator opening degree θ7 is set by throttle control.

Next, FIG. 8 shows step 1 in the control flow of FIG.
An example of the control flow for determining the target throttle opening θ7 when 07 is selected (throttle control) is shown. In step 131, the accelerator opening α and the throttle opening f(α) as shown in FIG. Select one map from multiple maps showing the relationship between. In Figure 9, straight line A
In Figure 1, the gear position of transmission 3 is neutral, reverse, and 1.
This is a map showing the relationship between the accelerator opening α and the throttle opening f(α) when the vehicle is in the 3rd gear position, and curves B and C
shows the map when the gear position is 4th and 5th gear respectively. In this case, when the gear position is 4th or 5th, the driving force of the tires is small and the running resistance is large, so the accelerator is Increased gain of throttle opening r(α) with respect to opening α6
Next, in step 132, the value of the throttle opening r(α) relative to the accelerator opening is directly determined using the map selected in step 131, and in step 133, the target throttle opening θ7 is determined as θa=f(α). .

Next, FIG. 1O shows a control flow for determining the target throttle opening θ7 when step 120 is selected in the seventh control flow (vehicle speed control). This is done by α-■ Amafubu in which the target vehicle speed (A) for constant vehicle speed control is made to correspond to the accelerator opening degree α as shown in FIG. That is, in step 141, the target vehicle speed ■1 is obtained from α-■7mass, and in the next step 142, the feedback system of the vehicle speed ■ as shown in the fourth diagram is performed. 11 (1-PD?AI+control), the target throttle opening θ7 is obtained and the throttle control 4B is performed.
(PID control). The above-mentioned equation (6) is used as the control equation for this vehicle speed control. That is, ENV ←v,
−■ θ7←θt + Ga * E N V-GS * (E
NV-ENVI) -C, *<ENV-2*ENV1 +ENV2) ENVI ←ENV ENV2 ←ENVI For the next calculation, change the previous vehicle speed deviation ENV1 to the current vehicle speed deviation ENV, and the vehicle speed deviation ENV2 from the time before the previous time to the current vehicle speed deviation ENV. The memory is shifted to the previous vehicle speed deviation ENVI.

Further, when the vehicle speed V and the target vehicle speed V7 are significantly different from each other at the time of transition to vehicle speed control, correction is made so that the vehicle speed ■ appears on the α-vT map. Furthermore, the response may be delayed by decreasing the control gains 04 to G.

Furthermore, in step 142 of FIG. 10, in place of the α-■ map shown in FIG. 11, an α-■ map as shown in FIG. , control characteristics in vehicle speed control can be improved.

That is, in the average vehicle speed range, the regular vehicle speed range, or the vehicle speed corresponding to the accelerator opening at the time of entry into vehicle speed control, by reducing the speed gain, it is possible to prevent hunting in the far range of the vehicle.

By controlling the vehicle speed as described above, when a constant vehicle speed is required, it is possible to correct the influence of running resistance, etc., so that stable running is possible at a vehicle speed that corresponds to the accelerator opening degree.

Further, in the control flow of FIG. 7, when step 122 is selected (acceleration control), the target throttle opening θ7
The control for determining will be explained. Control in this case requires two characteristic maps. That is, the 13th
Reference accelerator opening degree α for vehicle speed V as shown in the figure. Hail ■-α. map (this is called the "zero g line") and the accelerator opening difference Δα as shown in Figure 14.
The target acceleration g7 for the target acceleration is Δα−g7. V-α. The map shows the vehicle speed at which the vehicle is in a steady state (a state in which running resistance and engine driving force are balanced) for each accelerator opening. Therefore, due to differences in vehicle characteristics (air resistance, engine horsepower), zero g
The lines are different. On the other hand, the Δα-g7 map is a characteristic map of the desired acceleration g. This Δα is the current accelerator opening α and the reference accelerator opening α. It is caused by the difference between

Assume now that in FIG. 13, when the vehicle is running in a steady state, the accelerator opening degree is α8 and the vehicle speed is vl. At this time, v11α exists on the zero g line.

Assume that the driver depresses the accelerator pedal and the accelerator opening becomes α2. If Δα at this time is Δα, then Δα.

=α2-α1, and the target acceleration gT in Fig. 14
becomes gl. Then, to achieve this target acceleration (throttle control is performed).

If the driver maintains the accelerator opening at α,
If acceleration control is performed until the vehicle speed reaches V (positive acceleration control mode), and the accelerator opening remains at α2, but the vehicle speed increases to V, then Δ
α becomes Δα8−α times one α, and becomes Δα8×0. Therefore, the target acceleration is 1Δα, the Δα-g7 map is searched at 1, and the sign of the target acceleration is inverted. However, since there is a limit to deceleration (acceleration in the direction of deceleration) (because there is a limit to engine braking), it is necessary to set a limit on the target acceleration in the negative direction. The rest of the acceleration control is performed as described above (negative acceleration control mode).

Note that instead of the Δα-gt map shown in FIG.
Δα−g? as shown in FIG. 15 in which the gain of the target acceleration is reduced in the region of ? Using the map reduces the drop in acceleration during acceleration control, giving the driver the impression that the vehicle has good acceleration.

FIG. 16 shows a flowchart in the above-mentioned acceleration control. First, in step 151, ■-α of FIG.
. Standard accelerator opening α using the map. seek. Next, in step 152, the current accelerator opening degree and the reference accelerator opening degree α are determined. Calculate the difference Δα. Next, in step 153, Δ
Determine whether α is positive or negative. If Δα≧0, the program proceeds to step 154, reads the Δα-gy map shown in FIG. 14 or 15, and calculates the target acceleration g7 corresponding to Δα.

If Δα is O, then in step 155 the Δαgy map in FIG. 14 or 15 is read using 1Δα1 to obtain the target acceleration gt, and in the next step 156 the sign of the target acceleration is inverted. From step 154 or step 156, the process proceeds to step 157, where the target throttle opening θa is determined by performing feedback control W (PI-PD control) of the acceleration g as shown in FIG. n (PID control). The above-mentioned equation (9) is used as the control equation for this acceleration control. That is, ENG←gr g θ7-θ, +G, *(ENG-ENG 1) 10s*E
NG -G, *(ENG-ENG 1) -G,. *(ENG-2*ENG1+ENG2)ENG
I = ENC; ENG 2←ENG 1 For the next calculation, the previous acceleration deviation ENGI
to the current acceleration deviation ENG, and the acceleration deviation EN from the time before last.
G2 is memory shifted to the previous acceleration deviation ENG1.

In this way, acceleration control detects the engine's margin driving force (difference between engine driving force and running resistance) as acceleration,
Since this acceleration is controlled to be the target acceleration g, the driver's acceleration request can be reliably realized, and the acceleration feedback It? Because we are doing 11,
Sustainability and convergence of acceleration are improved, and acceleration performance is improved. Note that throttle control is used at the junction between throttle control and acceleration control to avoid any discomfort.

Is this the engine control according to the present invention? This is an explanation of one embodiment of the 111 m position, and in the above embodiment, when the engine and drive system are disconnected, when the gear is in reverse, when deceleration is requested, and when the throttle is fully closed. By switching the control means so that the throttle control is performed when the vehicle speed is below a predetermined value and the acceleration request is below a predetermined value, and the acceleration control is performed when the acceleration request is above a predetermined value, the driving state of the vehicle and the driver can be controlled. It is possible to perform engine control that satisfactorily meets the requirements of In addition to the embodiments described above, it is also possible to change the gear position depending on the vehicle speed, for example, use throttle control at low speeds, acceleration control at medium speeds, and vehicle speed control at high speeds. The gear position may be changed so that the throttle control is used in the 1st gear position, the acceleration control is used in the 2nd and 3rd gears, and the vehicle speed control is used in the 4th and 5th gears.

Further, the driving feeling can be improved even if two of the three control methods, ie, throttle control, vehicle speed control, and acceleration control, are not used all but are used by switching between them.

The above embodiment uses a throttle valve as an adjustment means for adjusting engine output in an on-to-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 the engine output, and this is applicable to the engine type. 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 an 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 operation of a throttle control system,
Figure 3 is a block diagram of the throttle control system, Figure 4 is a block diagram of the throttle control system.
Figure 6 is a block diagram of the vehicle speed control system, Figure 6 is a block diagram of the acceleration control system, Figure 6 is a flowchart of an interrupt program that determines the control amount of the throttle 7 actuator, and Figure 7 is a flowchart of the main program. , Fig. 8 is a flowchart of throttle control, Fig. 9 is a map showing the relationship between target throttle opening r(α) and accelerator opening, Fig. 10 is a flowchart of vehicle speed control, and Figs. 11 and 12 are A map showing the relationship between the target vehicle speed V7 and the accelerator opening degree α. FIG. 13 shows the reference accelerator opening degree α with respect to the vehicle speed ■. A map showing the relationship between
14 and 15 are maps showing the relationship between the target acceleration g7 and the accelerator opening difference Δα, and FIG. 16 is a flowchart of the brake control. 1.-Engine 2-.-Clutch 3--Transmission a 4-.Throttle valve 5...Control unit 6-.Throttle opening sensor 7--Vehicle speed sensor 8-Clutch stroke sensor 9-.DC motor

Claims (1)

[Claims] A control means for directly determining a control amount of an adjustment means for adjusting engine output based on an accelerator operation amount and controlling the adjustment means; at least two of the three control means: a control means that controls the adjustment means to control the adjustment means; and a control means that determines a target acceleration based on the accelerator operation amount and controls the adjustment means so that the target acceleration is obtained. What is claimed is: 1. An engine control device comprising: an operating means for switching and selectively operating each of these control means according to the driving state of the vehicle;