JPH0586931A - Rotational number controller for engine - Google Patents

Abstract

PURPOSE:To prevent drop in engine rotational number, and to maintain good driving function by operating and controlling an electromagnetic valve so that a by-pass route is fully opened until the idling rotational number of the engine reaches a fixed rotational number, when the temperature of cooling water is not less than a fixed temperature at the starting time of the engine. CONSTITUTION:A by-pass route 38 is provided, by which an intake-air throttle valve 32 of an intake-air route 30 communicated to an engine 2 is bypassed. An electromagnetic valve 46 for switching the by-pass route 38 through feedback control by means of a duty ratio, is provided in the middle of the by-pass route 38. The electromagnetic valve 46 is operated, and the amount of intake-air of the by-pass route 38 is increased or reduced, so as to control idling rotational number. When the temperature of cooling water is not less than a fixed temperature at the starting time of the engine 2, the electromagnetic valve 46 is operated and controlled by a control means 48 so that the by-pass route 38 is fully opened until the idling rotational number of the engine 2 reaches a fixed rotational number. Drop in the engine rotational number is thus prevented, and good driving function is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine speed control device, and more particularly to an engine speed control device capable of preventing a drop in engine speed at a high temperature start of the engine.

[0002]

2. Description of the Related Art Some engines are provided with a rotation speed control device for controlling the idle rotation speed during idling operation.

This engine speed control device is generally provided with a bypass passage bypassing the throttle valve of the intake passage,
An ISC valve (idle speed control valve), which is a solenoid valve, is installed in the middle of this bypass passage.
The valve is feedback-controlled by the duty ratio according to the idling operation state, so that the intake air amount in the bypass passage is increased or decreased to control the idle speed.

In this rotation speed control device, the ISC valve is actuated and controlled so that the bypass passage is fully opened for a certain period of time at the time of starting the engine and after the engine is started to prevent the engine speed from dropping immediately after the engine is started. I am letting you.

Further, such a rotation speed control device is disclosed, for example, in JP-A-60-19937. The one described in this publication increases the amount of air from the bypass passage at the time of starting the engine, and reduces the amount of air that increases at a rate that decreases as the temperature of the cooling water increases after starting the engine to the target amount of air. , The starting property and the stability of the engine after starting.

[0006]

By the way, in the prior art, if a certain time elapses after the engine is started, the ISC
The valve was operated by shifting from full-open control of the bypass passage to feedback control.

As described above, when the ISC valve shifts to the feedback control and is operated, when the engine is restarted due to heat damage due to heat damage, for example, the fuel in the fuel injection valve is in an evaporated state (vapor ) May not be completely removed from.

If the ISC valve shifts to the feedback control and is operated in such a state, the engine speed is suddenly reduced, and the idle speed becomes unstable.
Inconvenience such as engine stall occurred.

[0009]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a bypass passage bypassing the intake throttle valve of the intake passage communicating with the engine, and has a duty ratio in the middle of the bypass passage. An engine speed control device for controlling an idle speed by providing a solenoid valve that is feedback-controlled to open and close the bypass passage, and operates the solenoid valve to increase or decrease the intake air amount of the bypass passage to start the engine. At the time, when the cooling water temperature is equal to or higher than a set temperature, a control means is provided for controlling the operation of the solenoid valve so as to fully open the bypass passage until the idle speed of the engine reaches the set speed.

[0010]

According to the structure of the present invention, the control means is arranged to fully open the bypass passage until the idle speed of the engine reaches the set speed when the cooling water temperature is equal to or higher than the set temperature when the engine is started. Control the operation. As a result, even when the engine starts at a high temperature, the electromagnetic valve can be operated by feedback control after the engine speed has been increased to a predetermined level, and the engine speed can be prevented from dropping and the driving performance can be maintained well. be able to.

[0011]

Embodiments of the present invention will now be described in detail and specifically with reference to the drawings. 1 and 2 show an embodiment of the present invention. In FIG. 1, 2 is an internal combustion engine, 4
Is a cylinder block, 6 is a cylinder head, 8 is a piston, 10 is a combustion chamber, 12 is an intake valve, 14 is an exhaust valve, 16
Is an intake port, 18 is an exhaust port, 20 is an intake manifold, 22 is a manifold intake passage, 24 is an exhaust manifold, 26 is a manifold exhaust passage, 28 is a throttle body, 30 is a body intake passage, 32 is an intake throttle valve, and 34 is It is a surge tank.

The intake manifold 20 includes a combustion chamber 10
A fuel injection valve 36 is attached so as to be oriented in the direction. Although not shown, the fuel in the fuel tank is pressure-fed to the fuel injection valve 36 by a fuel pump.

A bypass air passage 38 is provided so as to bypass the intake throttle valve 32 and communicate the body intake passage 30 with the surge tank 34. That is, in the bypass air passage 38, the air introduction port 40 at one end has the intake throttle valve 32.
Is connected to the body intake passage 30 on the upstream side of
The air outlet 42 at the other end communicates with the surge tank 34. An ISC valve (idle speed control valve) (VSV) 46, which is a solenoid valve of a rotation speed control device 44 that opens and closes the bypass air passage 38 to adjust the intake air amount, is provided in the middle of the bypass air passage 38. There is.
As a result, the bypass air passage 38 is divided into the first bypass passage 38-1 and the second bypass passage 38-2.

The ISC valve 46 is connected to the control means 48. The control means 48 performs feedback control of the ISC valve 46 by the duty ratio to open and close the bypass passage 38 in order to increase or decrease the intake air amount of the bypass passage 38.

Further, the control means 48 is in communication with the fuel injection valve 36, the ignition switch 50, a water temperature sensor 52 for detecting the cooling water temperature of the engine 2, and a rotation speed sensor 54 for detecting the engine speed. ..

The control means 48 inputs signals from the respective sensors, and when the cooling water temperature is equal to or higher than a set temperature (for example, 100 ° C.) when the engine 2 is started, the idle speed of the engine 2 is set to the set speed ( For example, feedback target rotation speed 900 rpm + constant rotation speed 100 rpm = 1000 rp
ISC to fully open the bypass passage 38 until it reaches m)
The valve 46 is operated and controlled, and the ISC valve 46 is operated by feedback control after the idle speed reaches the set speed.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

In the control means 48, after the ignition switch 50 is turned on (step 102), it is judged whether or not the engine 2 is started (step 10).
4). That is, in step 104, it is determined whether the engine speed NE is less than 500 rpm.

When step 104 is YES and the engine 2 is starting, the control means 48 controls the operation of the ISC valve 46 so that the bypass passage 38 is fully opened (step 106).

On the other hand, if NO at step 104,
It is determined whether it is less than 2 seconds after the start of the engine (step 108). In the case of YES at step 108, since the engine is starting, the routine proceeds to step 106, and the operation control of the ISC valve 46 is performed to fully open the bypass passage 38.

If YES at step 108,
It is determined whether the cooling water temperature is equal to or higher than a set temperature (for example, 100 ° C.) (step 110). That is, step 110
Then, it is determined whether the engine 2 has been started in a high temperature state due to heat damage.

If YES at step 110,
Next, it is determined whether the engine speed (NE) is less than the set speed (feedback target speed 900 rpm + 100 rpm) (step 112).

If YES at step 112,
The routine proceeds to step 106, where it is judged that the engine 2 has started at high temperature, and the operation of the ISC valve 46 is controlled to fully open the bypass passage 38.

On the other hand, step 110 and step 1
If the answer is NO in 12, there is no problem such as heat damage. Therefore, the operation of the ISC valve 46 is normally controlled by feedback control (step 114).

As a result, when the temperature of the cooling water is equal to or higher than the set temperature (for example, 100 ° C.) at the time of starting the engine, even if a predetermined time (for example, 2 seconds) has elapsed after the starting, the engine speed (NE) remains unchanged. Until the set speed (feedback target speed 900 rpm + constant speed 100 rpm) or more is reached, the ISC valve 46 is operated so that the bypass passage 38 is fully opened, that is, the engine speed (NE) is once set to the set speed (feedback target). When the rotation speed + constant rotation speed) is reached, it is estimated that the fuel in the fuel injection valve 36 is out of the vaporized state (vapor), so that even if the ISC valve 46 is operated by the feedback control thereafter, Stabilizing the engine speed, preventing the engine speed from dropping, and avoiding engine stalls etc. to improve the driving performance. Can.

[0026]

As is apparent from the above detailed description, according to the present invention, when the cooling water temperature is equal to or higher than the set temperature when the engine is started, the bypass passage is formed until the idle speed of the engine reaches the set speed. By providing the control means for actuating the solenoid valve to fully open, the solenoid valve can be operated by the feedback control after the engine speed is increased to a predetermined level even when the engine is started at high temperature. Can be prevented and the driving performance can be favorably maintained.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an engine speed control device.

FIG. 2 is a flowchart of engine speed control.

[Explanation of symbols]

 2 engine 10 combustion chamber 28 fuel injection valve 74 throttle body 36 fuel injection valve 38 bypass passage 44 rotation speed control device 46 ISC valve 48 control means 50 ignition switch 52 water temperature sensor 54 rotation speed sensor

Claims (1)

[Claims] 1. A bypass passage bypassing an intake throttle valve of an intake passage communicating with an engine is provided, and an electromagnetic valve that is feedback-controlled by a duty ratio to open and close the bypass passage is provided in the middle of the bypass passage. In an engine speed control device that is operated to control the idle speed by increasing / decreasing the intake air amount of the bypass passage, when the cooling water temperature is equal to or higher than a set temperature when the engine is started, the idle speed of the engine is A rotation speed control device for an engine, comprising: a control means for controlling the operation of the solenoid valve so as to fully open the bypass passage until a set rotation speed is reached.