JPS6318016B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to controlling the rotational speed of an engine during idling based on the output of each sensor that detects the engine state, etc. The present invention relates to a method for smoothly controlling changes in engine speed under certain conditions.

Prior Art In order to maintain the idle rotation speed of the engine free of maintenance, the idle rotation speed is controlled in a closed loop to a target rotation speed according to the warm-up state of the engine, and when the engine is operating at the idling rotation speed or higher, the engine rotation speed is The amount of auxiliary air is increased depending only on the speed signal, and when returning from the above state to the idling operation state, the increased amount of auxiliary air is gradually decreased according to a predetermined function of time to reach the target rotation speed. A device that controls the return has been proposed in the past, for example, in Japanese Patent Application No. 70951/1983 by the present applicant.

Problems to be Solved by the Invention According to the device of the prior application, when coasting with the throttle valve fully closed (engine braking state), the engine is rotated in a speed range above the target rotation speed where rotation speed correction is not effective. The controlled auxiliary air amount is controlled to be close to the value of the air amount that provides the target rotational speed (the lower limit of the auxiliary air amount control range). If the clutch is disengaged when the engine rotation speed has decreased due to engine braking, the amount of air required by the engine will increase, but the increase in the amount of auxiliary air supplied will be delayed, so the engine rotation speed will have to drop significantly before reaching the target rotation speed. A phenomenon occurs that cannot be reversed. This phenomenon is not favorable for engine speed control during idling operation, and also has an adverse effect on the driving feeling of the automobile.

The present invention has been made in view of the above-mentioned disadvantages.The present invention detects a vehicle speed signal in addition to engine state detection signals such as engine warm-up state and engine rotational speed, and detects a vehicle speed signal when the engine is at low rotational speed (assistance based on engine rotational speed). When the air control amount is small), the auxiliary air supply amount is controlled in accordance with the vehicle speed signal, so that the engine rotation speed can smoothly shift to the target rotation speed during idling.

Means and operation for solving the problem In a method for controlling the rotational speed of the engine by adjusting the amount of auxiliary air supplied from an auxiliary air passage provided by bypassing the throttle valve of the engine of a vehicle, the current rotational speed of the engine is A first value corresponding to the auxiliary air supply amount is determined according to the difference between the detected value of the current rotational speed and a predetermined target value of the idling rotational speed to be controlled in a closed loop. determining a second value corresponding to the auxiliary air supply amount to be controlled in accordance with a detected value of the traveling speed of the vehicle, and determining the larger of the first value and the second value. The present invention provides an engine rotation speed control method characterized in that the auxiliary air supply amount is adjusted according to the value of the auxiliary air supply amount.

Embodiments The present invention will be described below with reference to embodiments shown in the drawings. In FIG. 1, an engine 10 is a known four
Cycle spark ignition engine, air cleaner 1
1. Air is taken in through an air flow meter 12, an intake pipe 13, a surge tank 14, and each intake branch pipe 15, and fuel, such as gasoline, is injected and supplied from an electromagnetic fuel injection valve 16 provided in each intake branch pipe 15. .

The main intake air amount of the engine 10 is regulated by a throttle valve 17 which is arbitrarily operated, while the fuel injection amount is regulated by an electronic fuel control unit 20. The electronic fuel control unit 20 detects the rotational speed measured by the rotational speed sensor 18;
This is a known method that determines the fuel injection amount using the intake air amount measured by the air flow meter 12 as a basic parameter, and also inputs signals from the warm-up sensor 19, etc., and thereby determines the fuel injection amount. Increase or decrease the injection amount.

The air conduits 21, 22 are provided so as to bypass the throttle valve 17, and an air control valve 30 is provided between the two conduits 21, 22. Further, one end of the conduit 21 is connected to an air inlet 23 provided between the throttle valve 17 and the air flow meter 12, and one end of the conduit 22 is connected to an air outlet 24 provided downstream of the throttle valve 17. It is connected.

The air control valve 30 is basically an electromagnetic (linear solenoid) type control valve, and changes the air passage area between the air conduits 21 and 22 by displacement of a plunger 32 that is slidable in a housing 31. .
Normally, the plunger 32 is set by a compression coil spring 33 so that the air passage area is zero.

By energizing the electromagnetic mechanism 34, an electromagnetic attractive force acts between the plunger 32 and the core 35, and the plunger 32 approaches the core 35 depending on the current flow.

In this way, the air control valve 30 is operated by the electromagnetic mechanism 3.
Plunger 32 and core 3 depending on the current flowing through 4.
5 and the air passage area between the air conduits 21 and 22 can be changed continuously, so the electric flow rate can be controlled by the current value.

The electromagnetic mechanism 34 is connected to the electronic control unit 6
Driven by 0. This electronic control unit 60 includes a distributor 18 (constituting a rotational speed sensor), a warm-up sensor 19, an electromagnetic clutch 27 that connects a compressor 26 for an air conditioner such as an automobile cooler, and a drive shaft of the engine 10.
An air conditioning switch 28 for turning on and off the air conditioner is connected to the air conditioning switch 28, and receives inputs such as an engine rotational speed signal, a cooling water temperature signal, and an air conditioner on/off signal.

Next, according to Fig. 2, the electronic control unit 6
0 will be explained in detail.

100 is a DA conversion circuit which converts a digital pulse signal synchronized with the engine rotation from the ignition distributor 18 into an analog signal voltage proportional to the engine rotation speed.

200 is a function voltage generation circuit, and warm-up sensor 19
Engine status signals such as the output signal of the engine and the on/off signal of the air conditioning switch 28 are input, and a preprogrammed function voltage is generated depending on the engine warm-up status, the air conditioner status, etc.

300 is an operational amplifier 301 and a capacitor 30
2. An integration circuit composed of resistors 303, 304 to 305 performs integration based on the difference between the output voltage of the function voltage generation circuit 200 and the output voltage of the DA conversion circuit 100.

400 is a holding circuit for a vehicle speed signal or an engine rotation speed signal, which includes diodes 401 and 40.
2,406,407, resistance 403,404,40
8. Comprised of a capacitor 405, it generates a voltage whose magnitude corresponds to an increase in vehicle speed or rotational speed, and when the vehicle speed or rotational speed decreases, the voltage gradually decreases with a certain time constant.

500 is an operational amplifier 501, resistors 502, 50
3,504, a voltage-current conversion circuit composed of a power transistor 505, which converts the voltage calculated by the integration circuit 300 and the engine rotation speed signal generation circuit 400 into a current for driving the electromagnetic mechanism 34. be.

600 is a DA conversion circuit which converts a digital pulse signal synchronized with the vehicle speed from the vehicle speed sensor 40 into an analog signal voltage proportional to the vehicle speed.

Next, the operation of the above configuration will be explained. First, a case in which signal voltages from the vehicle speed sensor 40 and the DA conversion circuit 600 are not applied to the holding circuit 400 in the configuration shown in FIG. 2 will be described. When the throttle valve 17 is closed and the engine 10 is in idle operation, the engine idle rotation speed is lower than the target rotation speed that should be set corresponding to the output voltage level of the function voltage generation circuit 200 of the electronic control unit 60. At this time, the potential of the DA conversion circuit 100 connected to the inverting input terminal of the integrator composed of a capacitor 302 and an operational amplifier (hereinafter referred to as OP amplifier) 301 through a resistor 303 is
It is lower than the output of the function voltage generation circuit 200.

Therefore, the output of the OP amplifier 301 is connected to the resistor 30.
The potential at point a divided by 4,305 is integrated and increases.

The voltage-current conversion circuit 500 controls the current supplied to the electromagnetic mechanism 34 so that the potential (voltage) at point a and the potential at terminal C of resistor 504 are equal.

That is, the current flowing through the electromagnetic mechanism 34 is increased so that the potential at point c increases as the potential at point a increases. As the current flowing through the electromagnetic mechanism 34 increases, the opening degree of the air control valve 30 increases and the amount of air bypassing the throttle valve 17 (auxiliary air amount) increases, which also activates the air flow meter 12 to increase the amount of fuel. The injection amount is increased, and the engine idle rotation speed increases toward the target rotation speed.

When the idle rotation speed increases to the set rotation speed, the output of the DA conversion circuit 100 and the output of the function voltage generation circuit 200 become equal, and the integration circuit 3
There is no potential fluctuation in the 00 output (point a), the amount of auxiliary air becomes constant, and the engine rotates at the target rotational speed.

In addition, when the engine rotation speed is higher than the target rotation speed, such as in racing conditions or when the car is running, the output voltage of the DA converter circuit 100 is input to the capacitor 405 to be the voltage at point b, and that voltage is applied to the diode 402, The potential at point a is increased through the resistor 404. Therefore, the amount of auxiliary air allows a certain amount of air to flow even during racing or under load operation.

Here, when the throttle valve 17 is fully closed, the engine speed will decrease, but the decrease in the amount of auxiliary air will
It is controlled by the potential at point b, which gradually decreases with a time constant determined by a capacitor 405 and a resistor 403. Therefore, the engine rotational speed drops smoothly and gradually, and the engine rotational speed does not fall below the set rotational speed.

Therefore, an example of the relationship between the amount of increase in auxiliary air and the engine rotation speed that exceeds the target rotation speed is displayed as shown in Figure 3, and when the engine rotation speed is controlled at the target rotation speed during idle rotation, the amount of auxiliary air also increases. The amount of increase in auxiliary air is almost constant and is zero, but as the engine rotation speed increases, the amount of increase in auxiliary air also increases.

Next, control when a vehicle speed signal is applied to the holding circuit 400 from the vehicle speed sensor 40 and the DA conversion circuit 600 according to the present invention will be described.

Figure 4 shows an example of the amount of increase in the required auxiliary air amount with respect to vehicle speed, and Figure 5 shows each parameter (throttle opening, vehicle speed, engine speed,
Fig. 4 compares changes in the amount of auxiliary air between the control method according to the present invention and the above-mentioned control method that does not include the present invention.

Each solid line A○ in FIG. 5 indicates a change in engine rotational speed according to the method of the present invention, and a broken line B○ indicates a change in engine rotational speed according to a control method that does not include the present invention.
Fig. 5 shows the change in the throttle valve opening when moving from the idle rotation state (throttle valve fully closed) to the running state and then back to the idle rotation state, shows the corresponding change in vehicle speed, and shows the change in engine speed. indicates the on/off operation of the clutch, and indicates the amount of auxiliary air that affects the state of. When controlling the target rotational speed at idle, the amount of auxiliary air is controlled only by feedback control, but when the engine rotational speed is high, such as when driving with the throttle open, the amount of auxiliary air is controlled by engine rotational speed correction (Figure 3). When the throttle is increased and the throttle is closed again to return to the idle state (especially when the engine rotates in the region C in Figure 3 between the target rotation speed and the engine rotation speed at which engine rotation speed correction begins), the inertia force of the vehicle increases. This allows the engine to rotate, and the electronic control unit 60 lowers the control amount within a controllable range to reduce the amount of auxiliary air in an attempt to bring the engine closer to the target rotational speed. At this time, in the control that does not include the present invention, the amount of auxiliary air decreases from the idle amount in the stationary position and becomes as shown by the broken line B○ in FIG. 5, and when the operation to disengage the clutch shown in FIG. As shown in ○, the engine rotation speed drops below the target rotation speed, resulting in poor driving feeling and giving the driver a sense of anxiety. To solve this problem, a vehicle speed sensor 40 and a DA conversion circuit 600 are provided, and the vehicle speed signal is applied in parallel with the engine rotation speed signal, so that the clutch is activated when the engine rotation speed is close to the target rotation speed during coasting. Even if the auxiliary air is turned off, the potential at point b is increased relative to the vehicle speed, and the amount of auxiliary air is increased relative to the vehicle speed, as shown in Figure 4.
The amount of auxiliary air is reduced by capacitor 405 and resistor 40.
It is controlled to gradually lower it with a time constant determined by 3. In other words, the amount of auxiliary air changes as shown by the solid line A○ in FIG. 5 due to the increase in the amount of auxiliary air due to the vehicle speed correction shown in FIG. 4, so even if the clutch is disengaged as shown in FIG. As in A○, the engine speed does not fall below the target speed and the driving feeling is good.

In the above embodiment, the air control valve is a moving plunger type linear solenoid type solenoid valve whose flow rate changes in proportion to the input current, but it is also possible to use a moving coil type solenoid valve or a current ON/OFF energized valve. A valve may be used to control the air flow rate by time ratio (duty ratio). In this case, the control circuit should of course be changed to control the NO-OFF duty ratio instead of controlling the current value.

Further, in the above embodiment, analog quantity control is performed, but it is also possible to divide the current value into certain bits and perform digital control using a microcomputer.

Effects As described above, the present invention detects the idle speed of the engine based on various states of the engine.
It is possible to perform closed-loop control to the optimum rotation speed, and it is possible to optimally control the amount of auxiliary air even in the event of a sudden increase in load, such as when the clutch is disengaged during coasting, to prevent engine stalling or poor driving feeling. It will not cause any damage.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an engine speed control system using the present invention, Fig. 2 is an electric circuit diagram showing one embodiment of the present invention, and Fig. 3 is a diagram showing the relationship between the amount of increase in auxiliary air and the engine speed. , Figure 4 is a diagram showing the relationship between the amount of auxiliary air increase and the vehicle speed,
FIG. 5 compares changes in various operating parameters of the engine over time between a system according to the present invention and a system not using the present invention. 21, 22... Air conduit, 30... Air control valve, 40... Vehicle speed sensor, 60... Electronic control unit, 100... D-A conversion circuit, 20
0...Function voltage generation circuit, 300...Integrator circuit,
400...signal holding circuit, 500...voltage/current conversion circuit, 600...DA conversion circuit.

Claims (1)

[Claims] 1. A method for controlling the rotational speed of an engine by adjusting the amount of auxiliary air supplied from an auxiliary air passage provided by bypassing the throttle valve of the engine of a vehicle, the method comprising: and detecting the running speed of the vehicle, and determining a first value corresponding to the auxiliary air supply amount according to the difference between the detected value of the current rotational speed and a predetermined target value of the idling rotational speed to be controlled in a closed loop. and determining a second value corresponding to the auxiliary air supply amount to be controlled in accordance with the detected value of the traveling speed of the vehicle, and determining a second value corresponding to the auxiliary air supply amount to be controlled according to the detected value of the traveling speed of the vehicle, and determining the larger of the first value and the second value. An engine rotational speed control method, comprising: adjusting the auxiliary air supply amount according to a value of the auxiliary air supply amount.