JPS6215740B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for improving the startability of an automobile engine, particularly during high-temperature restart.

When restarting an engine at a high temperature, for example, when the engine is temporarily stopped after continuous operation and there is no cooling effect from running wind or a radiator fan, and the engine and engine room are still in a high temperature state, the high temperature There is a large amount of vaporized fuel in the intake passage that had previously adhered to the wall, and the fuel in the float chamber is guided through the nozzle by percolation, so when the engine is started next, The intake air-fuel mixture introduced into the engine becomes very rich, and thus the air-fuel mixture has poor ignitability, and the engine is likely to have trouble starting.

Conventionally, in order to eliminate this drawback, a control device was installed in the air passage that opened when the engine was started at a high temperature, and air was introduced through the air passage into a position downstream of the throttle valve in the intake passage of the engine to dilute the air-fuel mixture. In addition, there is a type in which a control valve is further installed in the air passage to detect the complete explosion of the engine and close it, and prevent air from flowing into the intake passage after the complete explosion (see Japanese Utility Model Publication No. 55-34298). Are known.

On the other hand, if the throttle valve is opened more than the idle opening at the time of starting, the properly adjusted air-fuel mixture is sucked in by the carburetor, which improves starting performance.
In addition, if the throttle opener detects the intake pressure during deceleration and forcibly opens the throttle valve when the pressure exceeds the set pressure, the air-fuel mixture that becomes too rich during deceleration will be appropriately diluted and harmful components such as HC in the exhaust gas will be removed. known to decrease.

The present invention has good starting characteristics when restarting at high temperatures, and generates fewer harmful components in exhaust gas.
The purpose is to realize a device with a simple configuration that generates less harmful components in exhaust gas even during deceleration. a control device that opens the air passage when the engine starts at a predetermined intake air temperature or higher; and a control valve that closes the air passage by detecting negative pressure in the intake passage when the engine is completely exploded;
A throttle opener that opens the throttle valve slightly larger than the idle opening using the elastic force of a spring, and sets the throttle valve to the idle opening using negative pressure introduced with a delay from an intake pipe connected via a delay device. A negative pressure chamber of the throttle opener is in communication with an air passage between the control device and the control valve. An example of the implementation of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is an air passage connecting the air cleaner 2 and the intake passage 3, 4 is a control device that opens the air passage 1 at the time of starting when the intake air temperature is higher than a predetermined temperature, A bimetallic temperature-sensitive valve 4a, which is disposed at the opening to the air cleaner 2, deforms and begins to open the air passage 1 to the atmosphere when the intake air temperature exceeds a predetermined temperature, and a start signal obtained by detecting the start of the engine. It consists of a solenoid valve 4b that opens when excited and opens the air passage 1. FIG. 2 shows an example of the intake air temperature-air passage 1 opening characteristic of the bimetallic temperature-sensitive valve 4a.
For example, the passage 1 is closed up to 50°C;
The effective opening area begins to open at 50°C and increases linearly from 50°C to 60°C, and remains constant above that temperature. Reference numeral 5 denotes a control valve in which a negative pressure chamber 5a on one side of the diaphragm is connected to the intake passage 3, and is operated by the negative pressure of the intake passage 3 at the time of complete combustion of the engine to close the air passage 1.The control valve 5 is, for example, Third
As shown in the figure, it has the characteristic of operating and closing at a negative pressure of -10 mmHg or more. 6 is a throttle opener, the diaphragm 6a of which is connected to the throttle valve 7 via a lever, and the elastic force of a spring 6b causes the throttle valve 7 to move from the idle opening position via the diaphragm 6a and the lever. It consists of a dart pot device that can be opened slightly wide, and has a characteristic of opening, for example, by 8 degrees due to the elastic force of a spring 6b when the negative pressure is -250 mmHg or less (including when the engine is stopped) as shown in the fourth figure.
(The idle opening degree in this embodiment is about 2 degrees.) The throttle opener 6 is connected to the negative pressure accumulator chamber 8.
It communicates with the intake passage 3 through a check valve as a delay device 9, and between the negative pressure accumulation chamber 8 and the check valve 9 through a passage 10 between the electromagnetic valve 4b and the control valve 5. It communicates with the air passage 1. The check valve has a valve body 9b which is pressed toward the upstream side of the intake passage 3 by a spring 9a to close the valve, and the valve body 9b has a jet 9c.
is provided. The connection structure between the lever of the throttle opener 6 and the throttle valve 7 is as known in the art.
The opening can be controlled by the throttle opener below a predetermined opening (8 degrees in the example), and when the opening is above the opening, the opening and closing are controlled in conjunction with the accelerator without being affected by the throttle opener. and
The opening operation of the throttle valve 7 by the accelerator is not interfered by the opener 6.

Now, if the engine is restarted at a high temperature of 50°C or higher, the bimetallic temperature sensing piece 4a opens the air passage 1 with an opening area corresponding to the intake air temperature, and the solenoid valve 4b
While the starter switch 11 is on, a starting signal is applied to open the air passage 1, and the control valve 5 is also opened because the negative pressure in the intake passage is low before complete explosion. Therefore, air flows into the intake passage 3 via the air passage 1. Also, at this time, the negative pressure chamber of the throttle opener 6 is released to the atmosphere through the air passage 1 communicating through the passage 10, so the throttle valve 7 is activated by the elastic force of the spring 6b as shown in the first figure (solid line).
The opening is slightly larger than the idle opening (dotted line). In this way, the air-fuel mixture downstream of the throttle valve 7 is diluted appropriately according to its temperature, improving startability and reducing harmful components such as HC in the exhaust gas. When the engine completely explodes, the control valve 5 operates to close the air passage 1 because the negative pressure in the intake passage 3 becomes -100 mmHg or higher, for example, so that air is prevented from flowing into the intake passage 3, and the engine is completely exploded. This prevents the engine from misfiring and harmful components in the exhaust from increasing due to excessive dilution of the air-fuel mixture after detonation.

If the starting switch is opened after the engine has completely exploded and the application of the starting signal is stopped, the solenoid valve 4b will also open in the air passage 1.
As a result, the atmosphere release passage to the negative pressure chamber of the throttle opener 6 is also closed. Thus, after a complete explosion, when the negative pressure in the intake passage 3 becomes -350 mmHg or more, the negative pressure is transferred to the negative pressure chamber of the throttle opener 6 via the jet 9c of the valve body 9b of the check valve 9 and the negative pressure accumulation chamber 8. The throttle valve 7 gradually moves from the position shown in the first diagram (solid line) to the idle opening degree shown by the broken line. The delay time provided by the check valve 9 and the negative pressure accumulator 8 is selected to be the time required for the idle state to stabilize after a complete explosion (approximately 1 second or less).

Next, the negative pressure in the intake passage 3 is -250 mmHg, for example.
Assuming that the following negative pressure state is transitioned to a deceleration state, the throttle valve 7 is closed to the opening position of about 8 degrees as shown in the figure by the elastic force of the spring 6b, and then is decelerated, for example, from -500 to - A high negative pressure of 600 mmHg is gradually introduced to the throttle opener 6 via the jet 9b of the valve body 9c of the check valve 9 and the negative pressure chamber 8, so the throttle valve 7 gradually idles from the opening position of about 8 degrees. Return to open position. Therefore, the air-fuel mixture in the intake passage 3 does not become too rich and the amount of harmful components such as HC discharged does not increase. When the throttle valve 7 is opened again and the engine is accelerated, the negative pressure in the intake passage 3 is smaller than the negative pressure in the negative pressure chamber of the throttle opener 6, so the valve element 9b of the check valve 9 immediately resists the spring 9a. Valve open throttle opener 6
Since the negative pressure in the negative pressure chamber and the negative pressure accumulating chamber 8 drop instantaneously, the throttle opener 6 (specifically, the connection part between the throttle opener and the throttle valve 7, such as a stopper, etc.) about 8
It quickly moves to the opening position of 0.5 degrees, and thereafter waits at that position until the above-mentioned re-operation.

As described above, according to the present invention, when the engine is started at high temperature, the control device and the control valve are opened, air is allowed to flow into the intake passage through the air passage, and the throttle valve is moved from the idle opening position by the spring of the throttle opener. I opened the valve slightly wider, so
Engine startability is improved and harmful components in the exhaust are not increased. Also, the throttle opener is communicated with the intake passage via the negative pressure accumulator and delay device, so the air-fuel mixture remains stable even during sudden deceleration. It is possible to prevent an increase in harmful components in the exhaust gas due to over-concentration of the fuel, and to prevent the idle operation from becoming unstable and stopping the operation immediately after the complete explosion at high temperature startup. Furthermore, since the throttle opener is connected to the air passage which is released to the atmosphere at the time of high-temperature startup through the negative pressure chamber, the opening operation of the throttle valve by the throttle opener at the time of high-temperature startup and the sudden opening of the throttle valve during deceleration are prevented. It has the effect that the closing prevention action can be achieved with a simple structure.

[Brief explanation of the drawing]

FIG. 1 is a diagram of one embodiment of the present invention, and FIGS. 2 to 4 are diagrams illustrating its operation. DESCRIPTION OF SYMBOLS 1... Air passage, 3... Intake passage, 4... Control device, 5... Control valve, 6... Throttle opener, 7... Throttle valve, 8... Negative pressure accumulation chamber, 9... Delay device .

Claims (1)

[Scope of Claims] 1. A control device provided in each air passage connecting the intake passage of the engine with the atmosphere, which opens the air passage when the intake air temperature is higher than a predetermined starting temperature, and the intake air when the engine is fully detonated. A control valve that detects the negative pressure in the passage and closes the air passage, and a throttle valve that opens slightly larger than the idle opening due to the elastic force of a spring, and is connected to the intake pipe through a delay device. It is characterized by comprising a throttle opener which sets the idle opening by negative pressure introduced with a delay, and a negative pressure chamber of the throttle opener communicates with an air passage between the control device and the control valve. An engine starting acceleration device. 2. The engine starting promotion system according to claim 1, wherein the control device comprises an electromagnetic valve that opens in response to a starting signal and a bimetallic temperature-sensitive valve that starts opening the air passage to the atmosphere from a predetermined intake air temperature or higher. Device.