JPS6047447B2 - Blow-by gas intake device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for sucking blow-by gas from an engine into an intake system under conditions that improve engine startability.

Generally, when an internal combustion engine continues to operate and then stops, gasoline evaporation gas is generated in the intake manifold due to the vaporization of fuel adhering to the inner wall surface of the intake manifold, and further upstream from the carburetor there is a float of the carburetor. Evaporated gas in the float chamber flows in from the air vent connected to the chamber and accumulates therein.

Therefore, when the engine is restarted next time, these evaporative gases are inhaled all at once, and the fuel from the carburetor is added to them, so the intake air-fuel mixture becomes extremely rich when the engine is restarted. This not only makes it difficult to restart the engine, but also increases the generation of harmful gases such as HC. Therefore, Japanese Patent Publication No. 47-10133 as a prior art discloses that the amount of gas drawn into the intake manifold from the crank chamber of an internal combustion engine is gradually increased as the engine load increases using a control valve that is linked to the intake negative pressure. When the temperature is high, a large amount of blow-by gas is sucked into the intake manifold by providing the control valve with a bimetal that fully opens the control valve when the temperature is high. In this way, it is proposed to prevent the intake air-fuel mixture from becoming rich when starting the engine.

However, the bimetal in this prior art control valve is
When the temperature is high, the control valve is closed completely. When the temperature is high, the control valve is kept fully open even after the engine has started, and the intake manifold is
Since a large amount of blowby gas is inhaled even after the engine is started, the air-fuel ratio of the intake air-fuel mixture becomes too lean after the engine is started.

The present invention provides a control valve that links the blow-by gas sucked into the intake manifold with the intake negative pressure, as in this prior art.
To prevent the air-fuel ratio of the intake air-fuel mixture from becoming lean after starting the engine by fully opening the engine when the temperature is high, by performing the full opening operation only for an appropriate period of time when starting the engine. There are things.

In addition to the first invention, another invention improves not only the high-temperature startability but also the low-temperature startability of the engine by cutting the intake of blow-by gas into the intake system when starting the engine at low temperatures. It is.

Next, an example of the present invention will be explained with reference to the drawings. In the drawing, 1 is an engine, 2 is an intake manifold equipped with a carburetor 3 and an air cleaner 4, and 5 is for sucking blow-by gas from the engine 1 into the intake manifold 2. A conventionally known flow control valve 6 is provided in the blow-by gas passage 5, and the control valve 6 has a valve box 7 as shown in FIG.
It consists of a magnetic valve body 8 and two springs 9 and 10, which are slidably provided in the valve box 7, and when the valve body 8 slides in the direction of the intake manifold due to negative pressure in the intake manifold 2. Accordingly, a certain negative pressure value (e.g. -100 to -2007TL/R
rLHg) As the valve element 8 moves away from the first valve seat 11, the flow rate gradually increases and reaches its maximum value. seat 13
The structure is such that the flow rate is gradually reduced by being throttled.

A first excitation coil 14 for attracting the valve body 8 is provided on the outer periphery of the valve box 7 of the control valve 6, and the excitation of the coil 14 maintains the valve body 8 at the opening degree that provides the maximum flow rate. In the electric circuit 16 that connects the excitation coil 14 and the battery 15, there is an engine starting switch 17 or a switch that is linked to the starting switch and turns ON for an appropriate time, and the engine or engine. A high-temperature sensor 18 that sets the circuit to 0N when the temperature of the room, etc. exceeds a temperature at which starting is difficult, such as when evaporative gas accumulates upstream of the intake manifold 2 or the carburetor 3. are arranged in series. In this configuration, when the engine is started in a normal state, in other words, when the temperature of the engine or the engine room has not reached a temperature that would cause evaporative gas to accumulate on the upstream side of the carburetor, the temperature sensor 18 indicates 0N. Therefore, even if the start switch 17 is set to ON, the excitation coil 14 is not excited, and the blow-by gas of the engine is normally controlled by the control valve 6 linked to the intake negative pressure and is sucked into the intake manifold 2.

When starting the engine from a certain temperature condition where evaporative gas accumulates in the intake system such as the intake manifold, the intake pipe of the carburetor, or the air cleaner, making it difficult to start, the temperature range detector 18 is set to 0N. Turn the start switch 17 to 0N.
At the same time, the excitation coil 14 is energized to hold the valve body 8 in the control valve 6 at the maximum flow rate position regardless of the intake negative pressure, and a larger amount of blow-by is created in the intake manifold 2 than in the case of normal startup. Because the gas will be inhaled,
The air-fuel mixture, which has become extremely rich due to the evaporated gas entering the intake manifold via the carburetor, is diluted by this large amount of proby gas, and the mixture ratio can be corrected to a substantially constant appropriate mixture ratio. When the engine starts in this way, start switch 1
7 0FF cuts off the current to the excitation coil 14 and releases the holding of the valve element 8 at the maximum flow rate position by the excitation coil 14, so that the valve element 8 is opened in accordance with the engine load. Therefore, the amount of blow-by gas to the five-intake manifold 2 can be regulated to a smaller amount than at the time of starting.

Further, reference numeral 19 in the figure is a second excitation coil for attracting and holding the valve body 8 in the valve box 7 of the control valve 6 in the completely closed state O to the first valve seat 11; The electric circuit 20 connected to the battery 15 includes a switch 21 such as an engine starting switch that turns on when the engine is started, and a low-temperature sensor 22 that turns on only when the engine temperature is low. When starting the engine from a low temperature state (so-called cold start), the high temperature sensor 18 is OFF and the low temperature sensor 22 is 0N, so the switch 21 that is linked to engine startup is 0N. As a result, one of the excitation coils 19 is energized at the same time as the engine is started to keep the control valve 6 in a fully closed state, thereby cutting off the suction of bypass gas into the intake manifold 2 when the engine is started at a low temperature. This prevents blow-by gas from being sucked into the intake manifold 2 when the engine is started at a low temperature, and if the engine starts warming up in this state and the engine temperature rises, Since the temperature sensor 22 automatically turns OFF and releases the fully closed state of the control valve 6, the blow-by gas to the intake manifold 2 returns to the normal control state by the control valve 6.

As described above, the present invention provides five control valves in the blowby gas passage that introduces engine blowby gas into the intake manifold, which control the passage area of the blowby gas passage in conjunction with the engine load. In the blow-by gas suction device, the control valve is provided with an excitation coil that fully opens the control valve when energized, and a circuit connecting the excitation coil and a power source is connected to the A temperature sensor that becomes 0N when the temperature exceeds a certain temperature; and a switch that becomes 0N for an appropriate period of time in conjunction with the engine starting switch or the ON of the starting switch are installed in series. By inhaling a large amount of blowby gas, the control valve in the blowby gas passage prevents the air-fuel ratio of the intake air mixture into the engine from becoming rich when the engine is restarted in a high temperature state, and at the same time prevents the engine from starting. Since it is possible to prevent a large amount of blow-by gas from being inhaled later, it is possible to improve restartability of the engine at high temperatures and to reduce the generation of harmful gases such as HC when restarting the engine. This has the effect of reliably preventing the air-fuel ratio of the intake air-fuel mixture from becoming lean after starting the engine. Further, the second invention provides a control valve in a blowby gas passage that introduces blowby gas of the engine into the intake manifold, which controls the passage area of the blowby gas passage in conjunction with the load of the engine. In the bigas inhalation device consisting of:
The first control valve is fully opened by energization.
An excitation coil is provided, and a temperature sensor that becomes 0N when the temperature of the engine or engine room, etc. exceeds a certain temperature is provided in a circuit that connects the first excitation coil and the power source, and a starting switch of the engine or the starting switch that turns 0N. The time interval is 0N as appropriate in conjunction with
A second switch is provided in series with the control valve, and the control valve is provided with a second switch that fully closes the control valve when energized.
An excitation coil is provided, and a temperature sensor that turns to 0N when the engine temperature is low and a switch that turns to 0N when the engine starts are installed in series in the circuit that connects the second excitation coil and the power source. This prevents blow-by gas from being sucked into the intake manifold when starting the engine at a low temperature, and does not impede the choke effect at the time of starting the engine at a low temperature. It is easy to start the engine at a low temperature, and the engine warm-up time can be shortened.

[Brief explanation of drawings]

FIG. 1 is a diagram of an apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the control valve in FIG. 1. DESCRIPTION OF SYMBOLS 1... Engine, 2... Intake manifold, 3... Carburetor, 5... Blow-by gas passage, 6... Control valve, 14, 19 ...Exciting coil, 16,20...Electric circuit, 17,21...
...Switch, 18, 22...Temperature sensor.

Claims (1)

[Scope of Claims] 1. A control valve is provided in a blowby gas passage that introduces engine blowby gas into the intake manifold, and is configured to control the passage area of the blowby gas passage in conjunction with the engine load. In blow-by gas inhalation equipment,
The control valve is provided with an excitation coil that fully opens the control valve when energized, and a circuit connecting the excitation coil and a power source is provided with an excitation coil that is turned on when the temperature of the engine or engine room, etc. exceeds a certain temperature. 1. A blow-by gas intake device for an internal combustion engine, characterized in that a temperature sensor is connected in series with an engine starting switch or a switch that is turned on for an appropriate period of time in conjunction with turning on of the starting switch. 2. A blow-by gas intake device comprising a control valve in a blow-by gas passage that introduces engine blow-by gas into the intake manifold, which controls the passage area of the blow-by gas passage in conjunction with the engine load,
The control valve is provided with a first excitation coil that fully opens the control valve when energized, and a circuit connecting the first excitation coil and a power source is connected to a circuit that connects the first excitation coil to a power source when the temperature of the engine or engine room, etc. A temperature sensor that turns on when the temperature exceeds a certain temperature and a switch that turns on for an appropriate period of time in conjunction with the engine starting switch or the turning on of the starting switch are provided in series, and the control valve is not energized. A second excitation coil is provided to fully close the control valve, and a circuit connecting the second excitation coil and the power supply is provided with a circuit that is turned on when the engine temperature is low.
A blow-by gas intake device for an internal combustion engine, comprising a temperature sensor connected in series with a switch that is turned on when the engine is started.