JPH0578664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a device for controlling the idle rotation speed of a spark ignition engine, and in particular to a device for controlling the idle rotation speed of a spark ignition engine, and particularly for controlling the rotation speed by directly controlling the opening degree of a throttle valve at idle. It concerns what is controlled.

(Prior Art) Various configurations have already been proposed for closed-loop control of the idle rotational speed of an engine to always maintain it at a desired rotational speed depending on the state of the engine.

In a device that controls the engine rotation speed by controlling the opening degree of a throttle valve, the engine rotation speed is detected and compared with a target rotation speed, and the rotation speed is controlled to maintain the target rotation speed.

However, when the engine is idling, even if the throttle opening is changed, there is a large time delay until the rotational speed changes, and when the engine is in an unstable state, it is difficult to obtain excellent followability in rotational speed control.

On the other hand, in order to improve this, the throttle valve opening is detected by taking advantage of the characteristic that the engine speed corresponds to the throttle valve opening, and the throttle valve opening is controlled to maintain the target throttle valve opening. It is possible to consider things that improve performance and responsiveness.

However, in this throttle valve opening control, the rate of change in rotational speed with respect to the opening is large, and it has been difficult to obtain satisfactory control accuracy when the engine is in a stable idle state.

(Problem to be solved by the invention) The present invention has been made in view of the above problems, and
By selecting rotation speed control or throttle valve opening control depending on the engine operating condition, the idle rotation speed can be controlled accurately in idle operation conditions where the rotation speed is stable, and the followability and response can be improved when the rotation speed is unstable. An object of the present invention is to provide an engine rotational speed control device that can control the idle rotational speed with good performance.

(Means for Solving the Problems) In order to achieve the above object, the present invention comprises: a throttle valve provided in an intake pipe; an actuator that changes the position of a closing side stopper of the throttle valve; an opening detector that detects the engine rotational speed; a rotational speed detection means that detects the rotational speed of the engine; an idle detector that detects that the throttle valve is in the idle position; the opening detector and the idle detector. and a controller that controls the actuator based on a signal from the rotational speed detection means, the controller comprising: a preset target speed and the rotational speed detection means; a rotational speed control means for controlling the actuator so that the rotational speed becomes the target speed by comparing the rotational speed obtained by the rotational speed with the rotational speed obtained by the rotational speed from the preset target opening and the opening detector; Throttle valve opening control means that compares the obtained throttle valve opening and controls the actuator so that the throttle valve opening becomes the target opening; and the engine is brought into a stable idle operating state. and when it is determined that the engine is in the idle state detected by the idle detector and that the engine is in a stable idle operating state, the output of the rotational speed control means is Selection means for selecting the output of the throttle valve opening control means when it is determined that the engine is not in a stable idle state but in a transient state even in the idle state detected by the detector; and the selection means and a driver for driving the actuator by the output of the engine.

Furthermore, in a preferred embodiment of the present invention, when the throttle valve is not in the idle position, the target value is raised in the direction in which the throttle valve opens, and the position of the contact portion of the actuator with the throttle valve is opened accordingly. When the throttle valve again contacts the actuator that controls the opening at idle and the intake pipe pressure exceeds the set pressure or the engine speed falls below a certain set value that is higher than the target idle speed. The engine rotation speed control device starts closed loop control of the rotation speed or comparison control of the opening degree at idle with respect to a target value, thereby making it unnecessary to add a special device such as a dart pot.

(Example) Hereinafter, an example of the apparatus of the present invention shown in the accompanying drawings will be described.

FIG. 1 shows an embodiment of a device in which a single microcomputer is used to control fuel injection and engine speed during idling.

A throttle valve 3 is provided in the middle of an intake pipe 2 of the engine 1, and the throttle valve 3 is freely rotatable about a shaft 4, and is biased toward the fully closed side (direction A) by a spring (not shown). A lever 5 fixed to the shaft 4 comes into contact with a control shaft 7 of a DC motor 6, which serves as an actuator for controlling the opening degree (closed stopper position) during idling.

The lever 5 has a knob 8 on the side opposite to the side that contacts the DC motor 6, and this knob 8 is connected by a link to an accelerator (not shown) operated by the driver. At the tip of the control shaft 7 of the DC motor 6 is a movable shaft 10 biased toward the lever 5 by a spring 9. Electric contacts 11 and 12 are fixed to the movable shaft 10 and the control shaft 7, respectively. When brought into contact, the movable shaft 10 overcomes the biasing force of the spring 9 and retreats, causing the electrical contacts 11 and 12 to come into contact and close the electrical circuit.

An opening detector 14 is installed on the opposite side of the shaft 4 from where the lever 5 is fixed. An opening detector 14 detects the opening of the throttle valve 3 and sends the information as an electric signal to a control unit 13 serving as a controller. There is. The opening degree detector 14 is a well-known type that includes a built-in potentiometer and detects the opening degree based on the partial voltage between a movable contact and one terminal with respect to the voltage applied to both terminals.

The control unit 13 includes a pressure sensor signal that detects the pressure in the intake pipe 2, an ignition signal from the distributor 16, a water temperature sensor 17 that detects the engine cooling water temperature, a throttle valve opening detector 14, and a DC motor 6. Signals from built-in contacts 11 and 12 are input to the control unit 13, and the control unit 13 electrically controls the DC motor 6 and the electromagnetic fuel injection valve 18 provided upstream of the throttle valve 3 based on these input signals.

Fuel is pumped from C to the electromagnetic fuel injection valve 18 from a fuel pump (not shown), and the fuel pressure is adjusted by a fuel pressure regulator (not shown) to the pressure inside the intake pipe where the injection valve 18 is installed. The pressure difference is controlled to maintain a constant pressure difference.

Next, the internal structure of the control unit 13 will be explained based on FIG.

Microcomputer (CPU) 100, A-
A D converter 101, an input interface 102, an output interface 103, and a memory 104 are connected by a bus line 105 as shown in the figure.

The A-D converter 101 includes a throttle valve opening detector 1.
4. Analog signals from the pressure sensor 15 and water temperature sensor 17 are input, and A-D conversion is performed sequentially according to commands 3 from the CPU 100 issued according to a predetermined time schedule.

The input interface 102 includes an ignition signal from a distributor and an electric switch 19 (i.e., electric contacts 11, 1) which serves as an idle detector.
2) signal is input, the ignition signal is CPU100
The ignition gap is measured by a built-in counter (rotation speed detection means), and a rotation signal is obtained from the result.

The memory 104 stores information such as conversion values for the control program input signals of the CPU 100, and the CPU 100 reads the control program from the memory 104, and based on the control program, determines the injection pulse width for exciting the injector 18 and injecting fuel. The generation of drive pulses for driving the DC motor 6 is computationally controlled. The result is output interface 1
03, and the injection pulse width signal is amplified by a driver 107 for driving the injection valve and is output to the injection valve.

Further, a drive command signal for the DC motor 6 is output to a DC motor driver 106. As shown in the equivalent circuit using a solenoid valve, inside 106, the time corresponding to one step is determined by switching the voltages applied to both terminals of the DC motor 6 according to the forward rotation command signal and reverse rotation command signal, respectively. Power is supplied to and controlled by the DC motor 6.

Next, the operation will be explained based on the flow chart shown in FIGS. 3a and 3b.

In the main routine, when the power is turned on to the control unit 13, a start-up process 200 is performed, followed by a step 201 in which an increase in the amount of fuel injection is calculated based on the water temperature sensor signal and the throttle valve opening signal. next
Check in step 202 whether 100ms has elapsed.
Perform the following processing each time the process progresses.

If 100 ms has elapsed, the process proceeds to step 203, where the target value V ₀ of the throttle valve idling opening degree and the target value N ₀ of the closed-loop control of the rotation speed are calculated according to the water temperature sensor signal. Next, in step 204, it is determined whether the electric switch 19 is ON (closed).
205 detects the throttle valve opening degree V at that point,
Store in RAM. In steps 206 and 207, it is determined whether the idle condition is set in advance, and
Steps 208 to 210 when all three discrimination conditions are satisfied
The rotation speed is controlled in a closed loop.

Step when the set idle condition is not met
At 212, the throttle valve opening degree V is the target fully closed position of the throttle valve.
It is determined whether it is at V ₀ or not, and when V>V ₀ , the DC motor 6 is reversed by one step to move the throttle valve 3 in the direction of fully closing. When VV ₀ , DC motor 6
is rotated one step forward to move the throttle valve in the direction of opening.

On the other hand, when the electric switch 19 is open, that is, when the driver depresses the accelerator and the throttle valve 3 is far from fully closed and is open and the vehicle is running, the process proceeds to step 214, where the rotational speed N is increased. Setpoint higher than target rotational speed N ₀ for closed-loop control
It is determined whether it is higher than N ₀ +ΔN, and if it is higher, the fully closed position target value V ₀ is changed to V ₀ +V ₁ in step 215 in order to obtain the dart pot effect.

After that, the process proceeds to step 216, and the throttle valve opening degree V stored in the ROM in step 205 is determined to be V>V ₀
When , the DC motor 6 is reversed by one step (step 217), and at the same time, it is reversed by step 205.
The amount corresponding to the amount that the DC motor 6 reverses the throttle valve fully closed position stored in the RAM by one step (△
V _STEP ) (step 218). When VV _{is 0} , the DC motor 6 is rotated in the forward direction by one step (step 219), and in step 220, correction is made in the reverse direction as in step 218.

Steps 203, 208 to 210 correspond to the rotation speed control means of the present invention, and steps 203, 211 to 210 correspond to the rotation speed control means of the present invention.
213 corresponds to the throttle valve opening control means of the present invention, and steps 204 and 207 correspond to the selection means of the present invention.

The operations of the main routine described above are executed repeatedly. Further, when an ignition signal is input to the input interface 102, the input interface 102 synchronizes with it and sends an interrupt signal to the CPU 100.
100 immediately performs the interrupt processing shown in FIG. 4 based on the signal. That is, in step 221, the injection pulse width is calculated and determined according to the rotation signal obtained from the pressure sensor signal and the ignition signal, and in step 222
Set the injection time found in step in the output register and return to the main routine. An injection pulse width is formed based on the injection time set in the output register and output to the electromagnetic injection valve.

In this embodiment, a DC motor is used as the actuator, but the same effect can be obtained by using a step motor, a proportional solenoid valve, a servo motor using intake negative pressure, or a servo motor using hydraulic pressure or fuel pressure.

Further, in this embodiment, the fuel injection device is shown in combination with one that injects fuel from upstream of the throttle valve, but the same effect can be obtained even if the fuel supply device is combined with a carburetor or a fuel injection device having an injection valve for each cylinder.

(Effects of the Invention) As described above, the present invention includes: a throttle valve provided in an intake pipe; an actuator that changes the position of a closing stopper of the throttle valve; and an opening detection device that detects the opening of the throttle valve. a rotation speed detection means for detecting the rotation speed of the engine; an idle detector for detecting that the throttle valve is in an idle position; the opening degree detector, the idle detector, and the rotation speed detection means. An idle rotation speed control device for an engine, comprising: a controller that controls the actuator based on a signal from the engine; a rotational speed control means for controlling the actuator so that the rotational speed becomes the target speed by comparing the rotational speed with the throttle valve opening obtained from the preset target opening and the opening detector; a throttle valve opening control means for controlling the actuator so that the throttle valve opening becomes the target speed; and determining whether the engine is in a stable idle operating state; When the engine is in the idle state detected by the idle detector and it is determined that the engine is in a stable idle operating state, the output of the rotational speed control means is controlled to be in the idle state detected by the idle detector. a selection means for selecting the output of the throttle valve opening control means when it is determined that the engine is not in a stable idling state but in a transient state, and driving the actuator by the output of the selection means. Since the engine rotation speed control device is equipped with a driver to control the rotation speed, it is possible to select between rotation speed control and throttle valve opening control depending on the engine operating condition. It has the effect of being able to control the rotational speed, with good followability and responsiveness even when the rotational speed is unstable, and that the idle rotational speed can be controlled.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the overall structure of an embodiment of the present invention, Fig. 2 is a block diagram illustrating the internal structure of the control unit, and Figs. 3 a and b show processing of the microcomputer in the control unit. A flowchart showing the procedure, and FIG. 4 is a flowchart showing the contents of the ignition interrupt processing among the processing steps of the microcomputer in the control unit. FIG. 5 is a diagram corresponding to claims of the present invention. 3... Throttle valve, 6... DC motor, 13... Control unit, 14... Opening degree detector, 19... Electric switch.

Claims (1)

[Scope of Claims] 1. A throttle valve provided in an intake pipe, an actuator that changes the closing-side stopper position of the throttle valve, an opening detector that detects the opening of the throttle valve, and a rotational speed of the engine. an idle detector that detects that the throttle valve is in the idle position; and an idle detector that detects that the throttle valve is in the idle position; An engine idle rotation speed control device having a controller for controlling an actuator, wherein the controller compares a preset target speed with the rotation speed obtained by the rotation speed detection means, a rotational speed control means for controlling the actuator so that the rotational speed becomes the target speed; and comparing a preset target opening with the throttle valve opening obtained from the opening detector; a throttle valve opening control means for controlling the actuator so that the throttle valve opening becomes the target opening; and determining whether or not the engine is in a stable idle operating state; When it is determined that the throttle valve is in an idle state and the engine is determined to be in a stable idle operating state, the output of the rotational speed control means is detected, and the idle detector detects that the throttle valve is in an idle state. selection means for selecting the output of the throttle valve opening control means when it is determined that the engine is not in a stable idling state but in a transient state even if it is detected that the engine is in a stable idling state; An engine rotational speed control device comprising a driver for driving an actuator.