JPS6299649A - Idle warming-up device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To stabilize idling speed during warm-up, by installing a controlling device operating an idling air increment device for a while till the specified time elapses after engine temperature exceeds the setting value. CONSTITUTION:A first idle cam 8 regulates the idle opening of a suction throttle valve 4 according to temperature. An idle-up solenoid valve 5 bypasses the suction throttle valve 4 and increases idling air quantity. A water temperature sensor 6 detects engine temperature. After engine starting, a control circuit 7 operates the said solenoid valve 5 for a while till the specified time elapses after this detected temperature exceeds the setting value. Thus, idling speed-up is surely carried out till warming-up is over, so that idling speed is stabilizable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention stabilizes the engine rotation during warm-up of an internal combustion engine.
This invention relates to an improvement in an idle-up device that lasts only one hour.

(Prior technology) In order to stabilize the idle rotation after starting the engine at a low temperature, the intake throttle valve's eye 1 hell 1 no H degree is opened according to the temperature using a fast idle cam to increase the intake air intake during idling. , the idle speed is maintained so as not to decrease (see, for example, Japanese Patent Publication No. 56-41818).

By the way, this first idle cam, which serves as an idle-up device, operates in conjunction with a bimetal that senses the temperature of the engine, and as the temperature rises after engine startup, or as the heater that heats the bimetal is energized after startup, The regulated opening degree of the throttle valve is gradually reduced, and at the end of warm-up, the idle opening degree of the throttle valve is brought to the fully open position.

However, this first idle cam's control of the throttle valve's fully closed opening cannot always respond accurately to the warm-up state of the engine, and there may be variations in the precision of the first idle cam,
Due to the influence of the outside temperature, the first idle cam often falls off and the throttle valve returns to the fully closed position before the engine actually finishes, making the engine rotation unstable. .

Therefore, conventionally, a passage was provided that bypassed the intake throttle valve separately from this first 7' idle cam, and this passage had an electric
An idle up solenoid valve is installed that opens and closes depending on the engine cooling water temperature, and a water temperature switch that detects the engine cooling water temperature and operates the idle up solenoid valve controls the opening and closing of the idle up solenoid valve. Then, leave the made valve open and introduce additional intake air.

As a result, as shown in Fig. 6, in addition to the first idle cam opening the throttle valve to increase intake air, the idle up solenoid valve also adds up the intake air, and the idle up solenoid valve increases intake air. Even after the increase by the fast idle cam ends, the increase in air continues until the water temperature reaches the set value, so it is possible to reliably maintain the idle/idle concave rotation at a high level until the warm-up is completed.

(Problem to be solved by the invention) However, in this case, in order to ensure the stability of idle rotation, the temperature variation of the water temperature switch should be set to a somewhat high value, for example, about 75°C. Although it is necessary to ensure that the idle up solenoid valve remains open even after the restriction by the First Eye 1 Cam is lifted, on the other hand, if you do this, the water temperature switch will not turn off even after warming up. , the idle up solenoid valve would sometimes remain open.

The engine cooling water is circulated through the radiator by the thermostat, and until the water temperature reaches the temperature regulated by the thermostat, it does not flow to the radiator but circulates within the engine's water jacket until the temperature reaches the temperature regulated by the thermostat. When the set value is exceeded, the water flows to the radiator, and temperature control is performed to lower the water temperature based on the heat dissipated by the radiator, but the water temperature controlled in this way is subject to variations in thermostat accuracy. Therefore, the water temperature at the end of warm-up has a certain range.

When the temperature range of the water temperature controlled in this way and the variation in the setting value of the water temperature switch (li:
4. Even after the warm-up is complete, the water temperature switch won't turn off! A sequence arises.

For this reason, the set temperature of this water temperature switch is normally set lower than the temperature required for idling up, and even for water temperatures that are not very high after revving, the water temperature switch is reliably set to OI.
However, as a result, even if an idle up solenoid valve is installed, the set temperature of this idle up solenoid valve will be relatively lower, so the idle up by the fast idle cam will be lowered. There was a problem that the introduction of additional air after the end of the cycle was likely to be insufficient, and the stability of idling rotation could not necessarily be sufficiently increased.

The present invention aims to solve this serious problem.

(Problems and Means for Solving the Problems) As shown in FIG. Bypass F2 valve 10 and idle air JI! : idle air increasing means 12 for increasing the temperature of the engine; and temperature detecting means 13 for detecting the temperature of the engine.
and a control means 14 for operating the idle air increasing means 12 until a predetermined time has elapsed after the detected temperature exceeds the set value after the engine is started.

(Function) Therefore, since the introduction of additional air by the idle air increasing means 12 is stopped after a certain delay time has elapsed after reaching the set temperature at the end of warm-up, this set temperature may be lowered again. Even during the subsequent time delay 1111
The machine will advance and the idle rotation can be stabilized. Furthermore, by determining one set temperature in this manner, the idle air increasing means 12 or 11 will not remain in continuous operation even after the summer cycle is completed.

(Example) Examples of the present invention will be explained below based on the drawings.

In Fig. 2, 1 is an intake passage, 2 is a hot wire type 17' flow meter that extracts a part of the intake air and measures the intake air flow, and 3 is located upstream of the intake throttle valve 4 to inject fuel. The amount of fuel injected is controlled by a signal from a control circuit 7 composed of a microcomputer or the like so that a predetermined air-fuel ratio is achieved according to the intake air amount.

In order to regulate the idle opening degree of the intake throttle valve 4 according to the engine temperature, a fast idle cam 8 is provided, and as shown in FIG. The opening degree is gradually reduced as the engine warms up over time.

An idle up solenoid valve 5 as idle air increasing means is interposed in a passage 9 that bypasses the intake throttle valve 4 from upstream to downstream l\.

In this embodiment, the idle up solenoid valve 5 is controlled by the control circuit 7, and the idle up solenoid valve 5 is controlled by the control circuit 7 based on the output of the water temperature sensor 6 which detects the engine cooling water temperature. The idle up solenoid valve 5, which is opened when the engine is started, is closed when a predetermined period of time has elapsed after the detected water temperature reached the set value.

31A is a flow chart 1-+P) showing the control operation of the idle up solenoid valve 5, which will be explained accordingly.

First, in step 21, the water temperature is read from the output of the water temperature sensor 6, and this water temperature is set to a set value T corresponding to the end of warm-up.
Compare it with Wφ, and if it is below the set value, clear the timer in step 23 (φ) However, if the timer is not cleared, it increases by 1 per unit time door open>, step 25
Proceed to , turn on the idle up solenoid valve to increase the amount of idle air. On the other hand, the set value 'F
If it is equal to or greater than Wφ, the process proceeds to step 24, where a timer is set in advance and compared with a delay time 'Fφ. If it is within the delay time Tφ, the process proceeds to step 25 and the idle up solenoid valve is kept in the ON state f$ for t;1F. When the delay time 'rφ has elapsed, the process moves to step 26, where the idle up solenoid valve is turned off to stop increasing the idle air amount. FIG. 5 shows an example of the operating state of the idle up solenoid valve 5 and the fast idle cam 8. As the warm-up state progresses after startup, the idle opening degree of the throttle valve regulated by the first idle cam 8 decreases, and eventually, as the water temperature approaches the temperature TWφ near the end of the warm-up, the first idle cam 8 The cam falls and the throttle valve reaches its minimum opening. When the water temperature reaches 1゛Wφ, the timer starts operating, but the idle up solenoid/<Lube 5 remains ON and the idle air amount remains increased. When the timer value reaches a preset delay time Tφ from this state, the idle up solenoid valve 5
will close and the idle will either increase or stop.

In this way, after the first idle cam 8 finishes increasing the amount of idle air, additional intake air can be introduced by the idle 7' knob solenoid valve 5 until the warm-up is properly completed, and the idle rotation is increased. Stability is ensured.

In this embodiment, the idle up solenoid valve 5 is turned ON only when the warm-up RP is turned on, or when the electrical load increases, for example when the headlights or windshield wipers are operated, even after the warm-up is completed. In order to prevent the idle rotation from decreasing when the power steering pump load increases, it is also possible to turn on the idle up solenoid valve 5 and 6 when these conditions are detected. In order to prevent the intake air amount from suddenly decreasing when the engine is decelerating, resulting in a misfire of the engine, the idle up solenoid valve 5 may be turned on during deceleration.

(Effects of the Invention) As described above, the present invention does not operate the idle air increase means until a predetermined period of time has passed after the engine temperature exceeds a preset temperature. Since the temperature is increased, even if the set temperature is slightly lower,
Warm-up can be sufficiently promoted during the delay time, and the idle increase μ due to the fast idle cam
Nini f? Even if there is a temporal variation in motion, it is possible to reliably idle up until the machine warms up or cools down, thereby stabilizing the 7' I - I concave rotation in the wheat machine.

Figure 1 is a diagram corresponding to the claims of the present invention, Figure 2 is a schematic configuration diagram showing an embodiment of the present invention, and Figure 3 is a flow chart showing the control operation of the idle up solenoid valve. , FIG. 4 is an explanatory diagram showing the throttle valve opening characteristic due to the fast idle cam, and FIG. 5 is an explanatory diagram IA showing the increase characteristic of the idle air amount due to the idle up solenoid valve and the fast idle cam. FIG. 6 is an explanatory diagram illustrating the tendency of increasing the amount of idle air in the conventional engine.

■...Intake passage, 2...Air flow meter, 4...
- Intake throttle valve, 5... Idle up solenoid valve, 6... Water temperature sensor, 7... Control circuit, 8... Fast idle cam.

Figure 5 Figure 6

Claims (1)

[Claims] A first idle cam that regulates the idle opening of the intake throttle valve according to the temperature after the aircraft starts, an idle air increase means that bypasses the intake throttle valve to increase the amount of idle air, and a temperature that detects the engine temperature. An idle for an internal combustion engine, comprising: a detection means; and a control means for operating the idle air increasing means until a predetermined time has elapsed after the detected temperature exceeds a set value after the engine is started. up device.