JPS6248941A - Suction air quantity controller - Google Patents

Abstract

PURPOSE:To feed an engine with a sufficient suction air quantity and secure a smooth accelerating feeling, by installing a device setting an open-loop control value to the specified value as a control value which controls an actuator regulating the suction air quantity. CONSTITUTION:In a open-loop controlling state, both analog switches 801 and 802 of a selector circuit 800 are closed. Voltage in a condenser 401 of an integration circuit 400 comes to the specified value corresponding to an engine temperature, and current-energizing time for a solenoid mechanism of an air control valve becomes longer. Also when shifting to load driving by engine acceleration, an output voltage of the condenser 401 is gradually going up at a time constant depending upon a resistor 806 of the selector command circuit 800. Doing like this, at the time of acceleration, a smooth accelerating feeling is securable, and at the time of deceleration, an engine speed is smoothly reducible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake air amount control device that controls the rotational speed of an engine by appropriately adjusting the amount of intake air given to the engine depending on whether the engine is idling or not.

Conventionally, a control valve is set in the air passage that bypasses the throttle valve of the engine, and this control valve is operated at idle according to the comparison result between the engine rotation speed and the target rotation speed, and the air passage is disconnected. A technique for performing feedback control by varying the area so that the engine rotation speed during idling converges to a target rotation speed is already known, for example, from Japanese Patent Publication No. 49-40886.

However, conventionally, the engine speed control device performs feedback control not only when idling but also when not idling, that is, when operating under load.
When the engine speed increases due to load operation, the control valve is operated to close the air passage in an attempt to lower the engine speed accordingly. Therefore, during deceleration when the throttle valve is closed and the engine moves from a load operating state to an idling operating state, the amount of intake air to the engine is insufficient because the air passage is closed. During acceleration to transition to a load operating state, the above air passage is closed as the engine speed increases, so the amount of intake air to the engine cannot be adjusted appropriately in response to changes in the operating state. However, it was difficult to follow the engine speed smoothly.

In view of the above points, the present invention employs open loop control during engine load operation, and employs this oven loop control system. 11
At times, a control value (in other words, intake air amount) is given that is larger than during feedback control and corresponds to the engine temperature, and when the engine accelerates when switching from feedback control to open-loop control, the control value increases to the control value during open-loop control. It is an object of the present invention to provide an intake air amount control device that can supply a sufficient amount of intake air and provide a smooth feeling of acceleration.

Also, when the engine decelerates when switching from open loop control to feed bank control, the open loop control value is gradually reduced to the normal feed bank control value, thereby preventing a significant drop in engine speed during deceleration. An object of the present invention is to provide an intake air amount control device that can smoothly reduce rotation speed.

Therefore, in the present invention, feed pack control, which controls the engine's intake air amount so that the actual rotation speed matches the target rotation speed, and open loop control, which does not provide feedback, are applied to the engine operating conditions. In the intake air amount control device that switches and controls the intake air amount according to the engine temperature, the open loop control value is set to a value that corresponds to the engine temperature and is larger than the feedback control value as the control value that controls the actuator that adjusts the intake air amount. The invention is characterized by comprising the first means and a second means for increasing the control value from the feed pack control value to a predetermined oven loop control value when the engine accelerates when switching from feedback control to open loop control. do.

Further, the present invention is characterized by comprising a third means for gradually reducing the control value from the predetermined open-loop control value to the feedback control value when the engine decelerates when switching from open-loop control to feedback control. do.

The present invention will be described below with reference to an embodiment shown in the drawings. 1st
In the figure, an engine 10 is a known four-stroke reciprocating spark ignition engine, and an air cleaner 11. Air flow meter 12. Intake pipe 13. Surge tank 14. Main air is taken in through each intake branch pipe 15, and fuel, for example 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 an optionally operated throttle valve 17, while the fuel injection amount is regulated by an electronic fuel control unit 20. The electronic fuel control unit 20 is a known unit that determines the fuel injection amount using as basic parameters an engine rotational speed signal from a distributor serving as a rotational speed sensor and an intake air amount signal measured by an airflow meter 12. Warm-up sensor 19. Signals from the throttle sensor 25 and the like are input, and the amount of fuel injection is increased or decreased based on these signals.

The air conduits 21.22 are provided to bypass the throttle valve 17, and an air control valve 30 is provided between the side 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 a diaphragm type control valve, and the displacement of a diaphragm 33 whose outer periphery is wound between housings 31 and 32 is transmitted to a valve body 35 via a shaft 34 and a valve seat 36. It is of the type that opens and closes. The diaphragm 33 is displaced by the pressure difference between the chambers 37 and 38, and is biased by the compression coil spring 4o via the spring tray 39, and is given the closing force of the valve body 35.

A holding plate 41 is secured together with a diaphragm 33 by tightening between the housings 31 and 32, and the shaft 34 is guided in an airtight manner by a sleeve 42 provided on the holding plate 41.

Further, a small hole 43 is formed in the holding plate 41, and the atmosphere is introduced into the chamber 37 through this small hole 43.

Note that the valve body 35 is a needle valve, and the flow area formed between the valve body 35 and the valve seat 36 is continuously changed with respect to the amount of displacement of the shaft 34.

Furthermore, the air control valve 30 includes an electromagnetic mechanism 50 that indirectly changes the opening degree of the valve body 35.

This electromagnetic mechanism 50 is formed of an electromagnetic coil 51 wound around a resin bobbin and fixed to the housing 31, a fixed iron core 52 disposed at the center of the electromagnetic coil 51, and a magnetic material, and a pin 53. Leaf spring 5 fixed to housing 31
4, and a tube 5 provided to face the tip of the leaf spring 54.
5.56. The leaf spring 54 closes the tube 56 by its own spring force when the coil 51 is not energized, and closes the tube 55 by electromagnetic force when the electromagnetic coil 51 is energized. Here, the pipe 55 is open to the atmosphere for introducing atmospheric pressure into the chamber 38 , and the one-way 56 is connected to the surge tank 14 via a pipe 57 for introducing negative intake pressure into the chamber 38 .

Therefore, the air control valve 30 controls the opening degree of the valve body 35 (that is, the amount of auxiliary air that bypasses the throttle valve 17) according to the magnitude of the pressure within the chamber 38. It is determined by the proportion of time that the tube 56 that guides the intake negative pressure is opened, that is, the proportion of time that the electromagnetic coil 51 is energized.

Excitation of the electromagnetic mechanism 50 is controlled by an electronic air control unit 60. This electronic air control unit 60 performs two functions: feed control control that controls the intake air amount of the engine so that the actual engine rotation speed matches the set rotation speed, and open loop control that does not perform a feed bank. It switches and controls according to the operating conditions of the engine, and includes a distributor 18, a warm-up sensor 19 that detects the engine temperature, that is, a warm-up state, a compressor 26 for an air conditioner such as an automobile cooler, and a drive shaft of the engine 10. It is connected to an idle switch 28 that turns on and off the electromagnetic clutch 27 that connects the engine speed signal, coolant temperature signal, throttle signal, and air conditioner.

Off signal is input.

Next, the electronic air control unit 60 will be explained in detail with reference to FIG. 100 is a D-A conversion circuit to which an intermittent signal synchronized with engine rotation from the ignition distributor 18 is input, and this signal is transmitted to resistors 101, 102, 103.
, 104. Capacitor 106. transistor 10
8, the waveform is shaped as shown in FIG. Diode 109,1
A 10° resistor 105 outputs from terminal B the voltage shown in FIG. 3B, which is a superposition of a voltage proportional to the engine speed and a sawtooth applied voltage synchronized with the engine rotation (intermittent signal). Reference numeral 200 denotes a function voltage generation circuit, in which the output signal of the warm-up sensor 19 and the ON/OFF signal of the air conditioning switch 28 are manually input, and the output of the warm-up sensor 19 is amplified by a known amplification circuit 201 according to the engine warm-up state. It becomes a voltage signal. This voltage signal is applied to resistor 202. The on/off signal from the air conditioning switch 28 is transmitted through the diode 203 and the resistor 204.
It is output to a first comparison circuit 300 (described later) via a diode 205, and provides a comparison level D of the first comparison circuit 300. The first comparison circuit 300 includes resistors 301, . 302.30
3. The comparator 304 compares the output voltage of the DA conversion circuit 100 and the function voltage of the function voltage generation circuit 200. As shown in FIG. 4, the output characteristics of the function voltage generation circuit 200 are as shown in FIG. 4. The lower the engine temperature, the higher the output voltage. In this case, the output voltage increases as shown by the broken line in FIG. In the comparison circuit 300, D
The output voltage of the -A conversion circuit 100 outputs a signal C at a comparison level.

400 is an integrator circuit, and a capacitor 4 is connected in accordance with this signal C.
Resistor 4 serves as a constant current charging circuit that performs constant current charging or constant current discharging of 01, and operates when signal C is at the "0" level.
02,403. Transistor 409 and signal C are “1”
"Resistor 405, 4 as a constant current discharge circuit that works at the level
06,407. Diode 408. transistor 4
10. As shown by the broken line in FIG.
When the output signal is at the "1" level, the capacitor 401 is charged with a constant current, so the output voltage E increases, and when the output signal is at the "1" level, the capacitor 401 is discharged with a constant current, and the output voltage E decreases. 500 is a known oscillator that outputs a triangular wave voltage F with a constant period as shown by the solid line in FIG. A second comparator circuit that compares the pressures of both types is composed of a resistor 601 and a comparator 602, and outputs a pulse signal G that is at the 1" level only during a period when the output voltage E of the integrating circuit 400 is larger, as shown in FIG. 3G. do. 700 is an amplification circuit using an inverting amplifier 701 that inverts and amplifies the signal G of the second comparator 600, and the output after amplification is sent to the electromagnetic coil 5 of the electromagnetic mechanism 50 of the air control valve 30.
1. Reference numeral 800 denotes a switching circuit that switches the integrating circuit 400 between activation and inactivation, and when the integrating circuit 400 is inactive, switches the output voltage E to a predetermined value larger than normal as shown in FIG. It has analog switches 801 and 802 that turn off (open) when the throttle valve 17 is closed by a signal. Furthermore, this switching circuit 800 includes resistors 803 and 804.
,805. It is connected to the input end point of the first comparator circuit 304 via diodes 807 and 808, and to the base of the transistor 410 via a diode 808. Further, the switch 801 is connected to the function generation circuit 20
0 and the capacitor 401 of the integrating circuit 400 are connected to the resistor circuit 8.
Connect via 03,804,805,806.

Next, the operation of the above-mentioned constituent device will be explained. When the engine 10 is in idle operation with the throttle valve 17 closed, the idle rotation speed is determined by the electronic air control unit 1-1.
When the rotational speed is lower than the set rotational speed corresponding to the comparison level D determined by the function voltage generation circuit 200 of 60, the output of the DA conversion circuit 100 also decreases with respect to this comparison level D. Therefore, as shown in the center of FIG.
The output signal is always “0” as shown in the center of Figure 3C.
Even if it reaches the "L" level, the period of the "L" level is very short, and the output voltage E of the integrated integration circuit 400 rises as shown by the broken line in the center of FIG. In the comparator circuit 600, the period T during which the integral voltage E is larger than the triangular wave voltage F of the oscillator 500 (the period during which the comparator 602 is at the "1" level) increases, and the electromagnetic coil of the electromagnetic mechanism 50 of the air control valve 30 increases. 51 increases, which means that the opening degree of the air control valve 30 increases, and the amount of auxiliary air that bypasses the throttle valve 17 increases, increasing the rotational speed of the engine 10.On the contrary, during idling operation When the engine rotational speed is higher than the set rotational speed, the output of the D-A conversion circuit 100 is as shown in FIG. 3B.
Comparison level D gives the set rotation speed as shown on the right side of
Even if the output signal of the first comparison circuit 300 is always at the "L" level or "0" level as shown on the right side of FIG. 0'' level is very small, and the output voltage E of the integrated integration circuit 400 decreases as shown by the broken line on the right side of FIG. 3E. Therefore, the second comparison circuit 600
Then, the period T during which the integrated voltage E is larger than the triangular wave voltage E of the oscillator 500 (that is, the period during which the comparator 602 is at the “1” level) decreases, and the electromagnetic mechanism 50 of the air control valve 30
The proportion of time that the electromagnetic coil 51 is energized decreases, which means that the opening degree of the air control valve 30 decreases, the amount of auxiliary air that bypasses the throttle valve 17 decreases, and the engine 1
Decrease the rotation speed of 0.

In this way, the engine rotation speed is adjusted at idle when the throttle valve 17 is closed (that is, during feedback control).
The rotational speed is controlled by the electronic air control unit 60 to a set rotational speed corresponding to the comparison level D determined by the output of the function voltage generation circuit 200.

However, the comparison level D that determines the set rotation speed of the lever increases as the engine temperature decreases, as shown by the solid line in FIG. 4, depending on the output of the warm-up sensor 19. Since the speed can be increased, stable idling operation can be maintained.Furthermore, when the air conditioning switch 28, which is connected to and driven by the compressor 26 of an automobile cooler or the like, is connected to the engine lO, the on signal of this air conditioning switch 28 generates a function voltage. input to the circuit 200 and this circuit 20
Since the comparison level D is raised by 0 as shown by the broken line in FIG. 4, the set circuit speed can be switched to a high value, and the problem of impairing the performance of the compressor 26 or causing engine stall is eliminated.

Next, when the throttle valve 17 of the engine 10 is opened and the state is shifted from idle operation to load operation (that is, open loop control state), the analog switches 801 and 802 of the switching circuit 800 are both closed by the signal from the throttle sensor 25 ( ), and the switch 802 sets the non-inverting input level D of the comparator 304 of the first comparison circuit 300 to "
0'' level, the output of the comparator 304 becomes ``1'', the transistor 409 of the integrating circuit 400 is cut off, and the base potential of the transistor 410 is set to the ``Ow'' level via the dunode 808, so that the output of the comparator 304 becomes ``1''.
is also blocked. Therefore, the capacitor 4 of the integrating circuit 400
01 is cut off from the charging/discharging circuit, and the operation of the integrating circuit is stopped. On the other hand, since the analog switch 801 is also closed during the interval, a voltage signal is obtained by correcting the voltage signal from the amplifier circuit 201 of the function voltage generation circuit 200 according to the engine warm-up state by biasing it with the resistance circuits 803, 804, 805, and 806. is supplied to a capacitor 401 of this integrating circuit 400. Therefore, the voltage E of the capacitor 401 at this time, as shown by the broken line in FIG. 5, is higher than the normal output range shown in the diagonal "fa region" in FIG. 5 in which the set rotational speed is controlled during idling, and when the engine is warmed up. In other words, it becomes a predetermined value depending on the engine temperature, and in other words, the time ratio in which the electromagnetic coil 51 of the electromagnetic mechanism 50 of the air control valve 300 is energized (i.e., the amount of auxiliary air supplied by bypassing the throttle valve 17) is the set rotation speed at idle. The predetermined value is larger than the time ratio during speed control.When the throttle valve 17 is closed from such a load operating state to perform deceleration operation and shift to idle operation, the switching circuit 80
0 analog switches 801 and 802 are both opened, so that the first comparison circuit 300 and the integration circuit 400 are charged/discharged.
The discharge circuit restarts the operation for controlling the set circuit speed as described above, but the output voltage E of the capacitor 401 of the integrating circuit 400 is gradually lowered by the resistor 407 to the normal output range for controlling the idle set rotation speed. Since the amount of auxiliary air gradually decreases to the amount for controlling the idle set rotation speed, the amount of auxiliary air is large immediately after deceleration, and as a result, the negative pressure in the intake pipe 13 downstream of the throttle valve 17 suddenly increases immediately after deceleration. This can be avoided, and it is possible to make it work as a so-called dashpot.

Of course, even when shifting from the state where the set rotation speed is controlled during idling to load operation due to engine acceleration, the output voltage E of the capacitor 401 of the integrating circuit 400 gradually changes with the time constant determined by the resistor 806 of the switching command circuit 800. In order to increase and reach the above predetermined value indicated by the 50th broken line,
There is no possibility that the auxiliary air rises rapidly during acceleration and deteriorates the acceleration feeling or the exhaust gas characteristics.

In the above-described embodiment, the air control valve 30 controls the amount of auxiliary air that bypasses the throttle valve 17, but for example, the shaft 3 of the air control valve 30
It is also possible to control the amount of air during idling operation by controlling the opening degree of the throttle valve 17 with a displacement of 4.

In the above embodiment, an air control valve in which a diaphragm valve is actuated by an electromagnetic mechanism 50 is used, but an electromagnetic air control valve in which a valve body is actuated directly by the electromagnetic force of the electromagnetic mechanism 50 may also be used.

Further, although a cooling water temperature sensor is used as the warm-up sensor, an engine oil temperature sensor, a block temperature sensor, a timer using a bimetal and an electric heater, etc. may also be used.

Further, although the warm-up state of the engine and the connection state of the compressor are used as elements of the function voltage, the function voltage may be generated depending on other engine operating states.

As described above, according to the present invention, during open-loop control, a control value (i.e., intake air amount) that is larger than during feedbank control and corresponds to the engine temperature is given, and the acceleration when switching from feedback control to open-loop control is Sometimes, a smooth acceleration feeling can be obtained by increasing the open loop control value to the above value.

Additionally, when the engine decelerates when switching from open-loop control to feedbank control, the open-loop control value is gradually reduced to the normal feedbank control value, thereby preventing a significant drop in rotational speed during deceleration.
The rotational speed can be reduced smoothly, and the driving feeling when switching between idle and non-idle driving states can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the device of the present invention, FIG. 2 is an electric circuit diagram showing the electronic air control unit shown in FIG. 1,
3 is a signal waveform diagram of each part in FIG. 2, and FIGS. 4 and 5 are characteristic diagrams for explaining the operation of the apparatus shown in FIG. 1. DESCRIPTION OF SYMBOLS 10... Engine, 18... Distributor forming a rotational speed sensor, 30... Air control valve forming an actuator, 100... D-A conversion circuit, 200...
-Functional voltage generation circuit, 300...first comparison circuit, 40
0...integrator circuit, 800...switching circuit.

Claims (2)

[Claims] (1) Control by switching between feedback control, which controls the engine's intake air amount so that the actual rotation speed matches the target rotation speed, and open-loop control, which does not provide feedback, depending on the engine operating conditions. In the intake air amount control device, a first means for setting an open loop control value to a value corresponding to the engine temperature and larger than the feedback control value as a control value for controlling the actuator that adjusts the intake air amount; and second means for increasing the control value from the feedback control value to a predetermined open-loop control value when the engine accelerates when switching from feedback control to open-loop control. (2) A patent characterized in that it includes a third means for gradually decreasing the control value from a predetermined open-loop control value to the feedback control value when the engine decelerates when switching from open-loop control to feedback control. An intake air amount control device according to claim 1.