JPS6326268B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine idle rotation control device, and more particularly to an idle rotation control device that allows an engine to idle at the most preferable rotation speed depending on engine load conditions.

Generally, in an automobile engine, the engine rotational speed when the vehicle is stopped, that is, when the engine is in an idling state, is kept as low as possible within the limit that allows a stable operating state to be obtained. However, if this engine speed is set under normal operating conditions, if the engine is at a low temperature such as during a cold start, the atomization or vaporization of the air-fuel mixture may be poor, or the viscosity of the lubricating oil may be high. , stable idling cannot be achieved unless the engine rotational speed is increased to a certain level. For this reason, in conventional engines, when the engine temperature is below a predetermined value, the throttle valve opening of the engine in the idle state is slightly increased to increase the idle speed and enable stable idle operation. Some devices perform idle control.

However, this fast idle control has a problem in that it is not possible to control the idle rotation speed to the most suitable value for the actual temperature of the engine. Additionally, although this fast idle control does not take into account the engine load at all, idling is not necessarily performed under completely no-load conditions, and it is necessary to drive the torque converter of an automatic transmission, drive the air conditioner, etc. It is not uncommon for a load to be added to the engine by driving the engine or turning on lighting equipment, and this load causes fluctuations in the idle speed of the engine. Therefore, maintaining the engine idle speed at a desired value under various load conditions becomes an important issue.

Under such circumstances, a method has been proposed in which electrical feedback control is performed to make the idle speed match a target speed set under certain operating conditions. For example, the idling speed control device disclosed in Utility Model Application Publication No. 55-137234 inputs various conditions such as the use of the air conditioner mentioned above in the form of input information to a calculation device, and the calculation device inputs each input information. The most suitable target idle rotation speed is calculated according to the combination of A pulse having a duty ratio proportional to the difference between the two rotational speeds is outputted, and based on this output, the electric actuation control device controls the diaphragm type negative pressure response means, thereby controlling the opening degree of the engine throttle valve. The idle speed is automatically controlled to a desired idle speed.

The idling speed control device of the type disclosed in Utility Model Application Publication No. 55-137234, which controls the opening and closing of the throttle valve to control the idling speed to a target value, provides somewhat satisfactory results under normal conditions. Although this is possible, since it is a rough control by controlling the opening degree of the throttle valve, if the difference between the actual idle rotation speed and the target idle rotation speed becomes a small value within a predetermined range, this will be corrected. The drawback was that I couldn't do it.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an idle rotation control device of the type disclosed in the above-mentioned Utility Model Application Publication No. 55-137234, which is capable of precisely controlling the idle rotation speed. It is.

The engine idle speed control device according to the present invention includes an inflow air amount control system that controls the idle speed by adjusting the opening degree of the throttle valve during idle operation according to the load condition of the engine, etc. further comprising a fuel supply amount control system that controls the idle rotation speed by adjusting the air-fuel ratio of the mixed gas to the engine, and operates only the inflow air amount control system when coarsely controlling the idle rotation speed;
On the other hand, when precisely controlling the idle rotation speed, only the fuel supply amount control system is operated.

Specifically, in order to adjust the engine rotation speed, the inflow air amount control system includes a throttle valve that controls the amount of intake air supplied to the engine, a first actuator that drives and controls the throttle valve, and an idle rotation speed. The throttle valve includes a first actuator control device that drives and controls the throttle valve by driving the first actuator so that the rotational speed reaches the target idle rotational speed. In order to adjust the engine rotation speed, the fuel supply amount control system includes a supply control device that controls the amount of fuel supplied to the engine, a second actuator that drives and controls the supply control device, and an idle rotation speed that is set to a target idle speed. The second actuator control device drives and controls the supply control device by driving the second actuator so that the rotational speed is adjusted. The idle rotation control device includes a speed difference detector that compares a target idle rotation speed set according to the operating state of the engine with an actual idle rotation speed detected by the rotation detector and detects a difference between the two speeds; An actuator selection device that operates only the first actuator control device when the two speeds detected by the speed difference detector are above a predetermined value, and operates only the second actuator control device when the speeds are below a predetermined value. The actuator selection device switches between the inflow air amount control system and the fuel supply amount control system.
Therefore, according to the idle rotation control device of the present invention, when the deviation of the idle rotation speed is large, by controlling the throttle valve, it is possible to quickly control the rotation speed to near the target rotation speed, and the deviation is small. In some cases, it is possible to achieve a highly accurate and stable target rotational speed by controlling the fuel supply amount. In other words, by using a preferable control system that is suitable for the magnitude of deviation in idle rotation speed, highly accurate idle rotation speed control can be performed without impairing responsiveness.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an engine idle rotation control device according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a structural and functional diagram of an idle rotation control device of the present invention incorporated into an engine 1. As shown in FIG.

As is clear from FIG. 1, the intake system of the engine 1 includes an intake pipe section 2, a throttle valve 3, and an intake manifold 4. An air cleaner 5 is provided at the inlet end of the intake pipe section 2, and an air flow sensor 6 for detecting the amount of air flowing through the intake pipe section 2 is arranged downstream of this air cleaner. Furthermore, a fuel injection device 7 is provided upstream of the throttle valve 3 of the intake pipe portion 2 to inject fuel in an amount corresponding to the amount of incoming air detected by the air flow sensor 6. Control of this fuel injection device is performed by a microcomputer, which will be explained later.

The throttle valve 3 is operated and controlled by a diaphragm actuator 8, which is a part of an idle rotation control device, so that its opening degree is set during idle operation.

The actuator 8 is a diaphragm actuator having a diaphragm 9 and a pressure operating chamber 10 defined by the diaphragm 9. When the pressure in the pressure working chamber 10 becomes low, the diaphragm 9 moves to the left in the figure, thereby slightly opening the throttle valve 8 via a connecting rod 11 fixed to the diaphragm 9. It's summery. A hook 11a is provided at the tip of the connecting rod 11 so that the throttle valve 3 can be rotated clockwise (opening direction) in the figure when the connecting rod moves to the left together with the diaphragm 9. It is being

The pressure working chamber 10 is connected to the upstream side of the throttle valve 3 in the intake pipe section through an atmospheric pipe line 12, and is communicated to the downstream side of the throttle valve 3 in the intake pipe section 2 via a negative pressure pipe line 13. It is communicated. The atmospheric pipe 12 includes a first solenoid valve 14 which is a normally open valve.
A second solenoid valve 15 which is a normally closed valve is provided in the negative pressure line 13.
are arranged respectively. Therefore, under normal conditions, the pressure operating chamber 10 is maintained at atmospheric pressure, and the actuator 8 is at this time operating the throttle valve 3.
is set to be the minimum opening corresponding to normal idling operation.

The first and second solenoid valves 14 and 15 are controlled so that when one is in an operating region, the other is in a non-operating region, and this control is performed by a microcomputer 16. The microcomputer 16 includes, for example, idle operation information D1 from an idle detection device 17 that detects the closed state of the throttle valve 3 to detect the idle operation state of the engine, and engine temperature information from a water temperature sensor 18 that detects the engine temperature. Information D2, air conditioner ON-OFF from air conditioner drive switch 19
information D3, and actual idle rotation speed information D from the rotation detector 20 that detects the rotation speed of the engine.
4.Inflow air amount information D from air flow sensor 6
Engine operating state information such as No. 5 is input.

Although it is possible to perform some degree of idle rotation control using only the configuration described above, this configuration does not allow precise control of the idle rotation speed within a certain range as described above.
Therefore, in the present invention, the microcomputer 16 detects the difference D between the target idle speed Nset and the actual idle speed Nrpm, and
When the difference is greater than a certain predetermined value Dref, idle rotation control is performed by controlling the throttle valve 3, while when this difference is smaller than a certain predetermined value Dref, the fuel injection amount of the fuel injection device 7 is additionally controlled. By doing so, idle rotation control is performed.

Next, the operation of the idle rotation control device of the present invention will be explained with reference to FIG. In the flowchart of FIG. 2, the flowchart symbols .about. shown on the left side indicate one cycle of control, and control is performed, for example, one cycle per rotation, in synchronization with the rotation of the engine.

The engine starts and the microcomputer 16
When activated, it is first determined whether or not the vehicle is idling based on the idling operation information D1 (). here,
When it is determined that the engine is idling, operating conditions such as engine temperature and cooler operating state are detected (), and then a target idle rotation speed Nset is calculated based on information D2, D3, etc. This target idle rotation speed Nset is stored in the memory m of the microcomputer 16. Thereafter, the actual idle rotation speed Nrpm (according to information D4) is detected (), and this actual idle rotation speed Nrpm is also input to the microcomputer 16.

The microcomputer 16 is a central processing unit
Target idle speed calculated by CPU
Nset and the detected actual idle Nrpm are compared and calculated, and the difference D between these two rotational speeds is detected (). On the other hand, in the memory of the microcomputer 16, the above-mentioned 2.
A reference value Dset for the difference between the two rotational speeds is stored.
Next, the actual rotational speed difference D is calculated from the above reference value.
Compared to Dset().

When D>Dset, the microcomputer 16
is calculated based on the difference D between the two rotational speeds Nset and Nrpm, and generates a pulse-like correction signal having a duty ratio corresponding to this difference. This operation is performed by the formula I=(Nset-Nrpm)+I(). Here, I is an integral output value. This correction signal includes a closing signal S1 (outputted when the value I is negative) supplied to the first solenoid valve 14 to close the first solenoid valve 14 on the atmosphere side, and a second solenoid valve 15 on the negative pressure side. It consists of an opening signal S2 (outputted when the value I is positive) which is supplied to the second solenoid valve 15 to open it.

The first and second solenoid valves 14 and 15 receive a close signal S1 and an open signal S2 using pulse signals with a duty ratio proportional to the amount of rotation speed to be corrected.
The control is performed by (). Therefore,
Air in the pressure working chamber 10 is sucked in proportion to the amount of rotation speed to be corrected. The diaphragm 9 moves to the left with a stroke according to this suction amount,
Correspondingly, the connecting rod 11 moves to the left, and as a result, the throttle valve 3 is additionally opened by an opening corresponding to the amount of rotational speed to be corrected.

On the other hand, when D<Dset, the microcomputer 16 calculates the difference D between the two rotational speeds Nest and Nrpm.
A fuel injection correction signal S3 corresponding to this difference D is generated. This calculation also uses the signal S1
and as in S2, the formula I=(Nest−Nrpm)+
Performed by I(). This fuel injection correction signal S3 is generated by the fuel injection device 7 in accordance with the above-mentioned difference D.
The amount of fuel injected from the injection valve is controlled by adjusting the opening degree of the injection valve, thereby obtaining an air-fuel ratio corresponding to the amount of rotational speed to be corrected.

As described above, control is performed according to various conditions of the idle rotation speed.

[Brief explanation of the drawing]

FIG. 1 is a structural functional diagram of an idle rotation control device of the present invention incorporated into an engine 1, and FIG.
1 is a flowchart showing an example of the operation of the idle rotation control device of the present invention. DESCRIPTION OF SYMBOLS 1...Engine, 2...Intake pipe section, 3...Throttle valve, 7...Fuel injection device, 8...Diaphragm type actuator, 9...Diaphragm, 1
0...Pressure working chamber, 12...Atmospheric pipe line, 13...
Negative pressure pipeline, 14, 15...first and second solenoid valves, 16...microcomputer.

Claims (1)

[Claims] 1: a rotation detector that detects the engine rotation speed; a throttle valve that controls the amount of intake air supplied to the engine in order to adjust the engine rotation speed; a first actuator that drives and controls the throttle valve; A fuel supply control means for controlling the amount of fuel supplied to the engine, a second actuator for driving and controlling the fuel supply control means, and a target idle rotation speed and the rotation speed set according to the operating state of the engine. Speed difference detection means for detecting the difference between the two speeds by comparing the actual idle rotation speed detected by the detector, and determining the idle rotation based on the difference between the two speeds detected by the speed difference detection means a first actuator control means for driving and controlling the throttle valve by controlling the first actuator so that the speed becomes the target idle rotational speed, and the idle rotational speed is set to the target idle rotational speed based on the difference between the two speeds; a second actuator control means for driving and controlling the supply control means by the second actuator, and when the difference between the two speeds detected by the speed difference detection means is greater than or equal to a predetermined value; An engine idle rotation control device comprising actuator selection means that operates only the first actuator control means and operates only the second actuator control means when the value is below a predetermined value.