JPH04308331A - Intake pipe device of engine provided with fuel injection valve - Google Patents

Abstract

PURPOSE:To obviate troubles that an intake amount in idling is reduced 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 the body of the intake pipe around the throttle valve. CONSTITUTION:A starting fuel injection valve 15 conventionally provided on the downstream side of a throttle valve 10 is shifted to the upstream side of the throttle valve in an intake pipe 2 of an engine 1 provided on the downstream side of the throttle valve 10 with a fuel injection valve 14 and haivng a starting fuel injection valve 15. Attached oil and carbon are flushed away by fuel injected in cranking the engine and the following period at a set temperature or lower.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an intake pipe device for an engine which is equipped with a fuel injection valve downstream of a throttle valve and also has a starting fuel injection valve. This invention relates to an intake pipe device that has a function of preventing this.

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 means to prevent this, and in engines equipped with a fuel injection valve downstream of the throttle valve and a starting fuel injection valve, fuel is introduced into the upstream side of the throttle valve when starting the engine, and carbon, etc. The problem was solved by washing it off.

[0006]

[Means for Solving the Problems] As a means for solving the above-mentioned problems, in the present invention, the starting fuel injection valve, which was conventionally installed on the downstream side of the throttle valve, is installed on the upstream side of the throttle valve.

[0007]

[Operation] When the engine key switch is placed in the starting position, the fuel pump operates and at the same time the starting fuel injection valve operates to supply starting fuel according to the engine temperature, supplying fuel to the upstream side of the throttle valve. 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 a fuel injection valve 14 installed in each branch of the engine and a starting fuel injection valve 15 installed upstream of the throttle valve 10 of the throttle chamber 4, 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.

Therefore, at the same time that the engine 1 starts cranking by the starting motor, fuel pressurized by the fuel pump 12 is introduced into the throttle chamber 4 by the starting fuel injection valve 15. The starting fuel injection valve 15 is arranged close to the throttle valve 10 and its direction is similar to the throttle valve 10.
By directing the fuel toward the throttle valve 10, the fuel is sprayed onto the throttle valve 10 and washes its surface, and the dripped fuel flows along the wall of the throttle chamber 4 to the periphery of the throttle valve 10.

Since the starting fuel injection valve 15 injects fuel until the engine 1 reaches a predetermined temperature, if the throttle valve 10 is placed at the idle position or the low opening position, the starting fuel injection valve 15 injects fuel onto the surface of the throttle valve 10 to wash the surface. .

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. Note that the direction of the starting fuel injection valve 15 should be set in consideration of the direction of inclination of the throttle valve 10 during idling so that the fuel sprayed onto the upstream surface of the throttle valve 10 flows over the entire surface. preferable.

[0014]

According to the present invention, the throttle valve can be placed in the idle position by an extremely simple method of moving the starting fuel injection valve from the downstream side of the conventional throttle valve and installing it on the upstream side of the throttle valve in the intake pipe. Fuel is introduced into the throttle valve and the surrounding body during cranking and subsequent periods when the engine temperature is below the set temperature, allowing oil and carbon adhering to be washed away each time the engine is started. 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 15 Starting fuel injection valve 21 Electronic control unit 22 Key switch

Claims (1)

[Claims] Claim 1: In an intake pipe device for an engine that includes a fuel injection valve downstream of a throttle valve and also has a starting fuel injection valve, the starting fuel injection valve is installed in the intake pipe upstream of the throttle valve. An intake pipe device characterized by: