JPS60150451A - Engine speed controller - Google Patents

Abstract

PURPOSE:To control the engine speed accurately by providing means for comparing between the engine speed and the target level, means for producing pulses on the basis of comparison results and means for controlling an electromagnetic mechanism. CONSTITUTION:A distributor 18 will detect the engine speed while a function generator 60 will produce the control target level of engine speed and a comparator 60c will compare said signals. When the revolution is lower than setting level, a mono-stable multi-vibrator 60e will produce pulse signals having high duty ratio and apply onto an electromagnetic coil 51. Consequently, the idle revolution of engine can be controlled properly. While the number of parts can be reduced and the reliability and be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine rotation speed control device, and particularly to an idle rotation speed control device for a spark ignition engine.

[Prior art]

Conventionally, the idle rotation speed control device for spark ignition engines has a configuration in which a bimetallic air control valve is installed in the air conduit that bypasses the throttle valve, and by adjusting the amount of auxiliary air, the amount of fuel supplied can be controlled. It is known to adjust the rotation speed and control the rotation speed.

However, since the above-mentioned valve is configured to operate the valve body by displacement of a bimetal that serves as a type of timer, it only has the effect of increasing the idle rotation speed for a suitable period after the engine cold starts, and the air conditioning In order to control the idle rotation speed when the machine compressor is driven or by other control parameters, it is necessary to provide a control device for each purpose, which results in a complicated configuration, inhibits design freedom, and reduces reliability. The problem was that it was getting worse.

[Purpose of the invention]

The present invention has been made in view of the above points, and allows the idle rotation speed to be controlled by control parameters such as the engine warm-up state and air conditioner on/off, and has a simple configuration without the need to provide a control device for each purpose. The purpose of this is to improve reliability and enable accurate control of engine speed.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings.

In FIG. 1, an engine 1o is a known four-stroke reciprocating spark ignition engine, which takes in main air through an air cleaner 11, an air flow meter 12, an intake manifold 13, a surge tank 14, and each intake branch manifold 15, 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 adjusted by an optionally operated throttle valve 17, while the fuel injection amount is adjusted by an electronic fuel control unit 20. The electronic fuel control unit 1-20 is a known system that determines the fuel injection amount using the rotational speed detected by the ignition distributor 18, which serves as a rotational speed sensor, and the intake air amount measured by the airflow meter 12 as basic parameters. in,
In addition, signals from the warm-up sensor 19 and the like are used to increase or decrease the fuel injection amount.

The air conduit 21.22 is 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 a two-diaphragm control valve, which transmits the displacement of a diaphragm 33 whose outer periphery is wound between housings 31 and 32 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 a compression coil spring 40 via a spring receiver 39, thereby applying a closing force to the valve body 35.

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

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 with 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 is composed of tubes 55 and 56 provided to face the tip of the leaf spring 54. And the leaf spring 54
When the electromagnetic coil 51 is not energized, the tube 56 is closed by its own spring force, and when the electromagnetic coil 51 is energized, the tube 55 is closed by electromagnetic force. Here, the pipe 55 is open to the atmosphere for conducting atmospheric pressure into the chamber 88 , and the conduit 56 is connected to the surge tank 14 via a pipe 57 for conducting negative pressure into the chamber 38 .

Excitation of the electromagnetic mechanism 50 is controlled by an electronic air control unit 60. The electronic air control unit 60 includes a distributor 18 , a warm-up sensor 19 , a throttle switch 25 that detects whether the throttle valve 17 is closed or close to the opening, a compressor 26 for an air conditioner such as an automobile cooler, and the engine 10 . It is connected to an air conditioning switch 28 that turns on and off an electromagnetic clutch 27 that connects the shaft, and inputs an engine rotational speed signal, a cooling water temperature signal, a throttle signal, and an aircraft on/off signal.

Next, referring to FIG. 2, the electronic air control unit 60 will be explained in detail. The function generator 60a is the warm-up sensor 1
9. Connected to air conditioning switch ♀28, sensor 19,
A function voltage for controlling the engine speed is generated in response to the signal from the switch 28.

This function generator 60a is composed of a resistor 101.102, a transistor 103, a sensor 19, a resistor +01.1
The resistance values of 02 are R(19) and 1? (101)
, R(202>) and the power supply voltage is VC, the base potential of the transistor 103 is VcXR(19)/(R(+9)+R(1) when the air conditioning switch 28 is off.
02) This transistor 103 is turned on and has an empty circuit.
Warm-up sensor 1 is used as an emitter follower.
9 uses a thermistor whose resistance value R (19) changes as shown in Fig. 3 with respect to the cooling water temperature T.
The emitter potential of the transistor 103 becomes higher as the cooling water temperature T becomes lower, and becomes higher when the air conditioning switch 28 is on.

The D-Δ converter 60b is a known device that converts a digital pulse signal into an analog signal, for example, an analog voltage.
The ignition pulse signal is connected to a distributor 18 which serves as a rotational speed sensor, and the ignition pulse signal generated at a frequency corresponding to the engine rotational speed is waveform-shaped and then converted into an analog voltage.

Comparator 60C is resistor 104.105.106.107
, a comparator 108, and is connected to a function generator 60a and a DA converter 60b. Then, the comparator 60c uses the comparator 108 to compare a signal obtained by converting the actual engine rotation speed into a voltage with a function voltage corresponding to the set rotation speed, and if the actual engine rotation speed is less than or equal to the set shaft speed, " It outputs an "O" level signal, and conversely, when the rotation speed is higher than the set rotation speed, it outputs a "1" level signal.

The generator 1 generator 60d is a known frequency variable astable multi-high break using a comparator.
10.1 Mr. anti-117, transistor 11B, 1
19,=I is composed of an indenzer 120, and the oscillation frequency is determined by a resistor 113, a capacitor 120, and a comparator 110.
It is determined by the comparison voltage input to the non-inverting input terminal f-+ of . Therefore, the oscillation frequency changes depending on the output signal of the comparator 60c, and the output signal of the comparator 108 becomes "I".
When the level is "0", a pulse signal with a low oscillation frequency as shown by +a+ in FIG. 5 is generated, and when the level is "0", a pulse signal with a high oscillation frequency as shown in FIG.

The stable multi-hisolator F30E is lit anti-121
~125, capacitor 126, L transistor 127.
128, the output pulse (fl
It is triggered by ``j'' and outputs a pulse signal with a constant on-time width corresponding to this oscillation frequency.

1-'/transistor 127 is triggered by the output signal of the oscillator 60d, and when the oscillator 60d outputs the pulse signal shown in FIG.
The oscillator 60d turns on and off as shown in FIG.
When the pulse signal indicated by cl is output, it turns on and off as shown by fdl in FIG. In other words, the on-time width of the transistor 128 is constant, while the off-time width of the transistor 128 is constant.
In addition to the capacitor 126, it is determined by the emitter potential of the transistor 127, which is triggered -ζ, and the lower the conimic potential, the longer the off-time width of the I transistor 123 becomes. Therefore, the comparator 60 is composed of the oscillator 60d and the medium stable multi-by-break 60C.
The output signal of C constitutes a pulse generator that generates a pulse signal with a constant on-time width and a varying frequency.

The drive circuit 60f includes a resistor 129.1 and a transistor 130.
．． Consisting of 131, stable multi-high break 60
Output of e, caballus signal and su I” sotrus isochi 25
The energization of the electromagnetic coil 51 is controlled by turning it on and off.

The astable multi-break 60g generates a pulse signal of a constant frequency with a small on-time width, and when the throttle switch 25 is fully closed or opened to a degree close to that or more, it is connected to the drive circuit 60f and turns on the transistor 131. , control off.

In the above configuration, during engine idling operation when the throttle valve 17 is fully closed or close to fully open, the throttle switch 25 is turned on, and the opening degree of the air control valve 30 is controlled by the electronic air control unit 60. control unit 60
uses the output signals of the warm-up sensor 19 and the air conditioning switch 28 as input signals, and the function generator 60a uses these output signals to generate a function voltage (2) as shown in FIG.

The warm-up sensor I9 detects the engine coolant temperature, and the resistance value changes with respect to the coolant temperature T as shown in FIG.
When the air conditioner switch 28 is on, the engine cooling water temperature changes as shown by curve ENT in FIG. 4 with respect to the warm-up state of the engine 10, and changes as shown by curve B in FIG. .

The comparator 60c compares the function voltage (corresponding to the set rotational speed) with the signal obtained by converting the actual engine rotational speed into voltage from the DA converter 60b, and determines whether the actual engine rotational speed is below the set rotational speed. If the set rotation speed is "2," a "0" level signal is output, and if the set rotation speed is "2," a "1" level signal is output.

Therefore, when the actual engine rotational speed is less than or equal to the set rotational speed, the oscillator 60a outputs a high-frequency pulse signal shown by tel in FIG. A pulse signal with a high oscillation frequency and a large duty ratio is generated and applied to the electromagnetic coil 51 via the drive circuit 60f.

Therefore, the electromagnetic coil 51 as a whole has a longer energizing time, and the leaf spring 54 has a longer time to open the tube 56. Therefore, the negative pressure in the surge tank 14 is intermittently introduced into the chamber 38 for a long time, and the pressure in the chamber 38 is equal to the curve A2 in FIG.
1, the diaphragm 33 is displaced downward in FIG. 1, and the valve body 35 increases the opening area of the valve seat 36.

This increases the amount of auxiliary air that bypasses the throttle valve 17 and supplies it to the engine IO, and in conjunction with this, the air valve 1:J-make I2 operates to increase the fuel injection Q of the injection valve 16.
J injuries will increase. In this way, when the rotational speed of the engine 10 is below the set rotational speed, the amount of air and fuel supplied increases, increasing the rotational speed of the engine 1o.

On the other hand, when the actual engine rotation speed is higher than the set rotation speed, the oscillator 60e outputs a low frequency pulse signal shown in FIG.
A pulse signal with a low oscillation frequency and a small duty ratio as shown in FIG.

However, the time it takes to open the tube 55 with the game leaf spring 54 becomes longer.
Atmospheric pressure is intermittently introduced into the chamber 38 for a longer period of time than the negative pressure, and the pressure inside the chamber 38 increases as shown by curve AI in FIG. 6, causing the diaphragm 3 to shift upward in FIG. The ζ valve body 35 reduces the opening area of the valve seat 36. thus,
By bypassing the throttle valve 17, the amount of auxiliary air supplied to the engine 1o is gradually reduced, and the rotational speed of the engine 100 is lowered.

As described above, the engine rotation speed can be maintained at the set rotation speed corresponding to the function voltage V by controlling the energization of the electromagnetic mechanism 50) and the electromagnetic coil 510 according to the function voltage (2). Here, the function voltage ■ is the cooling water temperature T as shown in Figure 4.
When the engine 10 is insufficiently warmed up and the cooling water temperature is low, such as when the engine 10 is started in a cold state, the function voltage V is large and the rotational speed of the engine 1o is maintained high. To rotate an engine 0 stably by overcoming friction such as the viscosity of engine oil. Then, as the engine 10 is gradually warmed up and the cooling water temperature rises by 1'', the function voltage V gradually decreases, and the engine speed is gradually lowered to the normal idle speed as shown in FIG.

When the air conditioning switch 28 is turned on, the function voltage changes as shown by curve A in FIG. do. Therefore, even when the engine is idling, the compressor 26 is driven at a sufficient rotational speed.
At this time, the cooling capacity of the air conditioner of the own qJJ car is ensured sufficiently.

Further, when the throttle valve 17 is opened beyond the set opening degree and the engine 10 shifts to load operation with electricity applied, the throttle switch 25 is switched to the unstable multi-by-break 60g side, and the electronic air control unit 60 closes the electric mechanism 50. The control is released, the electromagnetic coil 51 is driven by a constant frequency pulse signal of the astable multi-high break 60g, and the air control valve 30 is maintained at a small constant opening degree.

In the above embodiment, the oscillation frequency is controlled in two stages, high and low, but the oscillation frequency of the oscillator 60d may be continuously changed by applying the output of the comparator 60c to the oscillator 60d through an integrating circuit.

Also, a variable frequency oscillator 60d as a pulse generator,
Using a monostable multi-high break 60e that outputs a pulse signal with a constant on-time width, the energization of the electromagnetic coil 51 was controlled by a pulse signal with a constant on-time width and a varying frequency. Using a constant astable multi-by break 60h and a monostable multi-by break 60i that outputs a pulse signal with a variable on-time width, the energization of the electromagnetic coil 51 is controlled by a pulse signal with a constant frequency and a variable on-time width. Good too. In Figure 8, astable multi-high break 60h is 5 to 30
A negative pulse with a constant frequency of approximately Hz is generated to trigger the monostable multi-high break 60i at regular intervals. The monostable multi-bi break 601 includes a switching transistor 140 for variable on-time width, a resistor 141, and resistors 142 to 146 constituting a known monostable multi-high break.
, capacitor 147.148, transistor 149.1
50, a trigger diode 15], a resistor 152 and a capacitor 153 forming a differentiating circuit, and when the engine rotation speed is below the set rotation speed, a comparator 60C is activated.
When the output of is at “0” level, the transistor 140 is
OFF and generates a pulse signal with a long ON time width as shown in FIG. Transistor l4() turns on, reduces the ζ time constant, and generates a pulse signal with a short on time width as shown by +al in FIG. Increase or decrease air volume.

In addition, although an air control valve of the type in which a diaphragm valve is actuated by the electromagnetic mechanism 50 is used, an electromagnetic air control valve in which the valve body is actuated directly by the electromagnetic force of the electromagnetic mechanism 50 is used.
Hello.

In addition, although a cooling water temperature sensor was used as a warm-up sensor, an engine oil temperature sensor, a valve temperature sensor 9', or a timer using a bimetal and electric heater may also be used.
Hello.

In addition, as an element of the function voltage, the warm-up state of the engine, 1
Although the connection state of the engine engine is applied, the function voltage may be generated depending on other engine operating states) and 7-(
4) Good.

As described above, according to the present invention, the idle speed of the engine can be appropriately controlled according to the warm-up state of the engine, whether the air conditioner is turned on or off, etc., and the control devices that were conventionally provided for different purposes can be unified. This has the excellent effect of simplifying the configuration. As a result, the degree of freedom in design is improved, and reliability is also improved due to a reduction in the number of parts.

In addition, since closed-loop control is performed in which the idle rotation speed is controlled while comparing it with the actual rotation speed of the engine, it is not affected by various external conditions of the engine such as differences in the viscosity of the engine oil. Another great effect is that stable rotational speed control can be performed.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
Electrical circuit diagram showing the illustrated electronic control unit, FIG.
FIG. 7 is a graph for explaining the operation, FIG. 8 is an electric circuit diagram showing the main part of another embodiment of the present invention, and FIG. 9 is a graph for explaining the operation of the embodiment shown in FIG. IO...engine, 17...throttle valve, 18.
... Distributor forming the rotation speed sensor, 21°22... Conduit, 26... Compressor, 30...
Air control valve, 50...electromagnetic mechanism, 60a...function generator. 60e... Comparator, 60d, 60e... Oscillator forming a pulse generator, insect stable multi-high break, 60h,
5Qi...Astable multi-by-break, stable multi-high break that forms a pulse generator, 6o...drive circuit. Patent attorney Takashi Okabe

Claims (1)

[Scope of Claims] 1. A conduit for supplying auxiliary air to the engine by bypassing the throttle valve, an air control valve having an electromagnetic mechanism and controlling the amount of auxiliary air by energizing the electromagnetic mechanism; an idle state detection means for detecting an idle state; a rotation speed detection means for detecting the rotation speed of the engine;
a target value generating means for generating a predetermined control target value according to the operating state of the engine; a comparing means for comparing a detection value of the rotational speed detecting means with the control target value; and a comparison result of the comparing means. a pulse generating means for generating a pulse signal whose on time width and/or frequency change depending on the pulse signal; and a driving means for controlling energization of the electromagnetic mechanism according to the pulse signal, the motor being not when the engine is idling. A rotational speed control device for an engine, characterized in that open-loop control is performed using constant pulses. 2. The engine rotation speed control device according to claim 1, wherein the function voltage changes as a function of a warm-up state of the engine and a connection state between the engine and a compressor for an air conditioner.