JPS6093164A - Controlling system for rotational speed of gasoline engine - Google Patents

Abstract

PURPOSE:To allow the amount of fuel to promptly follow the turning on and off of a specific electrical load such as, for example, air-condition system, by raising, by a predetermined amount, the level of the duty pulse wave of a solenoid valve for controlling the amount of air bypassing a throttle valve, when the electical load is applied to the engine. CONSTITUTION:A desired idle rotational speed is compared with an actual value and is computed, and therefore a solenoid 300 is energized by the output of a drive circuit 200 to carry out the turning-on and -off duty ratio control of a solenoid valve 7 disposed in a passage 6 bypassing a throttle valve 5 in a carburettor 1. When the engine is applied with an electrical load such as, for example, air-condition system, the rotational speed of the engine tends to lower. Therefore, in order to obtain the amount of bypass air which is previously set to maintain the desired rotational speed in accordance with the condition of load, the level of duty pulse wave shape is raised in accordance with the set value. With this arrangement, the air amount may be increased at once, and upon turning off of the load the level of the duty pulse wave form may be lowered to carry out the similar control.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rotation speed control method for a gasoline engine,
In particular, the present invention relates to a method for controlling the rotation speed of a gasoline engine during idling.

(Prior Art) Vehicles such as passenger cars and I/racks are equipped with electrical systems for lighting such as headlights and room lights, and power consuming devices such as car air conditioners and wipers.

The power supplied to these power consuming devices is obtained from a generator driven and rotated by the engine.

Immediately after the engine of a vehicle is started or when the vehicle is temporarily stopped, such as while waiting at a traffic light, the engine is in an idling state. When the engine is idling, no access is engaged, the carburetor throttle/help is mostly closed, and the engine is only receiving fuel from the carburetor's slow speed system. Therefore, it is in a low speed rotation state of, for example, about 750 rpm.

By the way, if an electrical device that consumes a large amount of power during idling operation mode, such as a car air conditioner, is used, a large load will be placed on the generator. This large load is also applied to the engine, but since the engine is idling, its rotational speed is low and its shaft output is also small, so such a load is a large load on the engine. This causes the engine's idling speed to drop, causing unpleasant vibrations.

In order to avoid such drawbacks, an idle rotation control method as shown in FIG. 1 has been conventionally used. In Figure 1, 1 is the carburetor, 2 is the main nozzle, 3 is the small venturi, 4 is the idle adjuster, screw, 5 is the throttle valve, 6 is the air bypass, 7 is the idle speed control valve, and 8 is the calculation of the computer, etc. This is a control unit consisting of a control device 100, a drive circuit 200, and a solenoid 300. Next, the operation of this device will be described. The engine rotation speed is detected by a crankshaft rotation angle sensor, etc., and is sent to the arithmetic and control device 100 as a signal θ. A target rotation speed is set in advance in the arithmetic and control device, and the signal θ is compared with the target rotation speed.
Based on the deviation signal, a pulse signal with a predetermined pulse width □ is sent from the drive circuit to the solenoid, and the idle speed controller I
-The roll valve is turned on and off to adjust the amount of air taken into the engine and control the rotation speed.

(During the thick technique j, +5 , +,',1,) like this t
In the C-feedback type idle speed control system, when an f'J load that consumes a lot of power, such as an air conditioner, is connected to the electric circuit or is disconnected, the generator output fluctuates temporarily, and as a result, the idle target The rotation speed changes as shown in FIG. 2(a). That is, when the air conditioner is turned on at the idle target speed, the engine speed drops below the target speed by 1-1, so the pulse width of the pulse formed by the drive device to increase the air 1- in the engine is The PI is increased as shown in Figure 2 (b), but due to the feedback system R, a certain amount of time has passed since the air conditioner was turned on before the amount of air sent to the engine increases [Figure 2 (C)], it was inevitable that the target idle speed would decrease. In addition, when the air conditioner is turned off, the engine speed instantaneously becomes 1-91 times lower than the set speed, but the pulse P2 generated by the drive device to reduce the amount of air 1111 also occurs during the 111I period. ;
Due to the yen difference, there was a drawback that the target idle speed increased.

(Object of the Invention) The object of the present invention is to adjust the idle speed even when the air conditioner is turned on or off by changing the basic level of the duty pulse that controls the opening degree of the idle speed control valve to adjust the amount of engine air. An object of the present invention is to provide a rotation speed control method for a gasoline engine that does not cause fluctuations in speed.

(Summary of the Invention) The gasoline engine rotation speed control method of the present invention is such that the idling rotation speed of the engine and the air amount corresponding to a specific electrical load are set in advance in an arithmetic control device, and the specified
When the load is opened and closed, the feedback control described above is set to almost zero, and the idle speed is kept constant by controlling the air bypass opening and closing means of the throttle valve so that a preset empty 91 product is obtained. It is to be kept as such.

(Example) An example of the present invention will be described with reference to FIG. In the present invention, the air I- for the load of the air conditioner is collected in advance.
, the amount of air A that increases when the air conditioner is turned on, as shown in Figure 3 (C), is the normal compressor (7)? 5j fI
I C, turn off the air conditioner 1lIf the air is reduced
' Write B in the data memory of the niI calculation control device. When the air conditioner is turned on, the arithmetic and control unit reads out the amount of air A required at this time, sends a command 411 to the drive unit, and the drive unit outputs a duty pulse oil painting. At the level α, a pulse having the same pulse width as normal is given to the solenoid [see Fig. 3 (1)]. As a result, the idle speed control valve compensates the air amount A by 1F.
The f dollar target rotational speed can be kept constant as shown in FIG. 3(a). Similarly, when the air conditioner is off, the arithmetic and control unit reads out the air i-B to be impeded at this time,
An instruction is given to the drive device, and the drive device sends a pulse whose duty pulse level is the basic level α to the solenoid. As a result, the idle speed control I/roll valve corrects the air amount B to keep the idle target rotation speed constant. In addition, when turning on and off a specific heavy load such as an air conditioner, feedback of the engine speed is hardly performed, and the system switches to the air amount control method described in ``2''.

(Effects of the Invention) As explained above, in the present invention, the amount of air for the load of the air conditioner is calculated in advance, and the amount of air added when the air conditioner is turned on and the amount of air reduced when the air conditioner is turned off are calculated. Since the adjustment is made by changing the basic level of the duty cycle that controls the idle speed control valve, the idle speed can be kept constant even when the power-consuming air conditioner is turned on or off. Furthermore, the present invention provides an idle speed control method that uses a method of controlling the air amount of the idle speed control valve by comparing the target speed and the current engine speed, and when a specific load such as an air conditioner is turned on or off, Since only the pulse level is changed without changing the pulse width of the duty pulse (that is, the engine speed feedback is kept as low as possible), there is no feedback delay and the idle speed does not fluctuate. It is possible to prevent vibrations caused by rotational fluctuations and engine stalls when power steering, lighting loads, etc. are applied.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of the idle speed 11th J'll power formula of a gasoline engine to which the invention is applied, Fig. 2 is a diagram explaining the conventional characteristics, and Fig. 3 is a diagram explanatory of the characteristics of the present invention. . ■...Carb 1/-ta 5...Throt I/Le valve 6...Air bypass 7...Idle speed controller I/Roll valve 8...
・Con I Roll Unit 'llf:j'l Applicant Isuku' Jidosha Co., Ltd.
Rihito -fr Rihito 1- Minoru Tsuji (1 other person)

Claims (1)

[Claims] The amount of air corresponding to a specific electrical load is set in advance in the arithmetic and control device, and when the specific load is turned on or off, the air bypass opening/closing means of the throttle valve is controlled so that the preset amount of air is obtained as described below. A gasoline engine speed control method that maintains the idle speed at a constant level.