JPH04308330A - Intake pipe device of engine provided with fuel injection valve - Google Patents

Abstract

PURPOSE:To obviate troubles that an intake amount is reduced in idlind and a throttle valve is defectively opened by oil and carbon attached and deposited in a gap between a throttle valve provided in an intake pipe of an engine and a body of the intake pipe around the throttle valve. CONSTITUTION:A fuel introducing path 17 branched from a fuel path 13 from a fuel pump 12 to a fuel injection value 14 is opened to the upstream side of a throttle valve in an intake pipe 2 of an engine 1 provided on the downstream side of the throttle valve 10 with the fuel injection valve 14. A switch valve 18 interlocked with the start and stop of a starting motor to be opened and closed is provided in the fuel introducing path 17 to introduce fuel pressurized by the fuel pump 12 in cranking of the engine 1 to flush away attached oil and carbon.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to an intake pipe device for an engine that is equipped with a fuel injection valve downstream of a throttle valve, and more specifically, to a system that prevents oil and carbon from accumulating on the peripheral edge of the throttle valve. This relates to an intake pipe device.

0002

[Prior Art] The throttle valve, which is installed in the intake pipe to control the amount of intake air in order to control the rotational speed of the engine, and the body around it have a small gap between them to prevent oil from the exhaust gas or blow-by gas that recirculates when the engine is idling. Carbon tends to adhere and accumulate, which reduces the amount of intake air during idling, leading to problems such as over-rich mixture and engine malfunction. Furthermore, it is well known that the diameter of the intake pipe is increased in order to increase the output of the engine, and the diameter of the intake pipe of a multi-cylinder engine is particularly large. If such a configuration is adopted in which an idle air passage bypassing the throttle valve is provided in the intake pipe to supply air at idle, the idle opening of the throttle valve will be set to an extremely small value, and the gap between it and the fuselage will be extremely narrow. Carbon etc. tend to adhere more easily and may cause the throttle valve to become stuck. Since the diameter of the intake pipe is large, a considerably large torque is required to open the large-diameter throttle valve, and if the intake pipe becomes jammed, it becomes even more difficult to open the valve.

[0003] As a countermeasure to this problem, it is considered that the shape and structure of the throttle valve and intake pipe are such that it is difficult for carbon to adhere and accumulate, as disclosed in Publication of Utility Model Publication No. 55-4535 and Publication of Utility Model Publication No. 55-28860. However, even a small amount of deposits cannot eliminate the concern that they may accumulate over time and cause a reduction in the amount of intake air during idling or jamming of the throttle valve.

Another countermeasure is to apply a solid lubricant such as molybdenum disulfide to the peripheral edge of the throttle valve and the body around it to make it easier to peel off even if carbon etc. adhere to it. Although it has been put into practical use, if the throttle valve has a large diameter and the idle opening is set to an extremely small value as mentioned above, the high suction negative pressure at idle will cause the throttle valve to curve and cause further damage to the fuselage. When they come close together, the lubricants may adhere to each other and cause the throttle valve to become stuck. Opening the throttle valve in such a state not only requires an extremely large torque, but also causes the disadvantage that when the throttle valve opens, a portion of the lubricant peels off, reducing the ability to prevent adhesion of carbon and the like.

[0005]

[Problems to be Solved by the Invention] The problem to be solved by the present invention is to prevent oil and carbon contained in the exhaust gas and blow-by gas recirculated during idling from accumulating in the gap between the throttle valve and the body around it. There is no effective way to prevent this problem, and this problem can be solved by introducing fuel into the upstream side of the throttle valve when starting the engine and washing away carbon, etc. in machines that have a fuel injection valve downstream of the throttle valve. did.

[0006]

[Means for Solving the Problems] As a means for solving the above-mentioned problems, the present invention provides a fuel introduction passage branching from the fuel passage leading from the fuel pump to the fuel injection valve and opening toward the upstream side of the throttle valve in the intake pipe. An on-off valve that opens and closes in conjunction with the start and stop of the engine starting motor was installed in the fuel introduction path.

[0007]

[Operation] When the engine key switch is placed in the starting position, the fuel pump operates and the starting motor is started at the same time.While the key switch is in the starting position, the on-off valve opens and the fuel flows upstream of the throttle valve. supply Fuel pressurized by the fuel pump is sprayed onto the throttle valve or flows along the wall of the intake pipe to the periphery of the throttle valve, washing away any oil or carbon that may have adhered to it.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. An intake pipe 2 of an engine 1 includes a duct 3 extending from an air cleaner (not shown), a throttle chamber 4, a surge tank 5, and an intake manifold 6. An idle speed control bypass passage 7 that bypasses the throttle valve 10 is provided, and a low temperature bypass passage 8 that bypasses the throttle chamber 4 is provided.

On the other hand, the fuel in the fuel tank 11 is pressurized by the fuel pump 12 and passes through the fuel passage 13 to the intake manifold 6.
The fuel is supplied to the fuel injection valves 14 installed in each branch and the starting fuel injection valve 15 installed in the surge tank 5, and the fuel pressure is adjusted to a predetermined pressure by a pressure regulator 16.

The electronic control unit 21 operates the fuel pump 12 when the key switch 22 enters the starting position based on signals from the key switch 22 of the engine 1 and the temperature sensor 23, and at the same time operates the regulator 9 of the low temperature bypass passage 8.
A driving signal is sent to the starting fuel injection valve 15 so as to supply starting fuel according to the engine temperature.

In addition to the above, a fuel introduction passage 17 is provided which branches from the fuel passage 13 and opens upstream of the throttle valve 10 of the throttle chamber 4, and an electromagnetically driven on-off valve 18 is installed in this fuel introduction passage 17. has been done.

The on-off valve 18 is opened by a drive signal sent from the electronic control unit 21 when the key switch 22 is placed in the starting position, that is, while the starting motor is started and cranking. , fuel pump 12
The pressurized fuel is introduced into the throttle chamber 4. By opening the fuel introduction passage 17 close to the throttle valve 10 and directing its direction toward the throttle valve 10, fuel is sprayed onto the throttle valve 10 and washes its surface, and the dripped fuel is also sprayed onto the wall of the throttle chamber 4. and flows to the periphery of the throttle valve 10.

Gasoline, which is a fuel, acts as a solvent to dilute, dissolve, and wash away oil and carbon adhering to the throttle valve 10 and the wall of the throttle chamber 4 around it, and this process is repeated every time the engine is started. Therefore, even if it is not completely removed every time, it does not accumulate to the extent that it affects the rotation of the engine 1 or the opening of the throttle valve 10. In addition, in order to ensure that the fuel sprayed onto the upstream surface of the throttle valve 10 flows over the entire surface, it is recommended to set the direction of the opening of the fuel introduction passage 17 in consideration of the direction of inclination of the throttle valve 10 during idling. preferable.

[0014] Since the fuel supplied through the fuel introduction passage 17 is supplied to the engine 1 as starting fuel, the burden on the starting fuel injection valve 15 is reduced, especially at low temperatures.

[0015]

According to the present invention, the fuel introduction passage is branched from the fuel passage leading from the fuel pump to the fuel injection valve, and is opened upstream of the throttle valve in the intake pipe. By simply installing it in the introduction path, fuel is introduced into the throttle valve and the body around it during cranking when the throttle valve is in the idle position, and the attached oil and carbon are washed away each time the engine is started. Can be done. Therefore, even if oil or carbon adheres to the engine, it does not accumulate, and problems such as over-enriched air-fuel mixture and engine malfunctions due to a decrease in the amount of intake air during idling, as well as valve opening failures due to gagging of the throttle valve, are eliminated.

[Brief explanation of drawings]

FIG. 1 is a layout diagram of an embodiment of the present invention.

[Explanation of symbols]

1 Engine 2 Intake pipe 4 Throttle chamber 10 Throttle valve 12 Fuel pump 13 Fuel passage 14 Fuel injection valve 17 Fuel introduction path 18 On-off valve 21 Electronic control unit 22 Key switch

Claims (1)

[Claims] 1. In an intake pipe device for an engine including a fuel injection valve downstream of a throttle valve, the fuel passage branching from the fuel pump to the fuel injection valve opens to the intake pipe upstream of the throttle valve. 1. An intake pipe device, characterized in that a fuel introduction passage is provided, and an on-off valve that opens and closes in conjunction with starting and stopping of a starting motor of an engine is installed in the fuel introduction passage.