JPS61171872A - Suction pipe of internal-combustion engine - Google Patents

Abstract

PURPOSE:To spray liquid fuel gathering in a suction pipe during cold starting and warming-up operation and to promote evaporation, by a method wherein the air is communicated with the interior of or a portion in the vicinity of a fuel reservoir, mounted to the inner wall of the suction pipe, through air cleaner. CONSTITUTION:A vent hole 5 is open to the interior or in the vicinity of a fuel reservoir 4 mounted to the inner wall of a suction pipe 1. A communicating pipe 6 is connected to the vent hole 5 through a connector 7, and the other end of the communicating pipe 6 is communicated with an air cleaner. During cold starting or warming-up operation of an engine, dense air-fuel mixture in a state about similar to liquid state, fed to a carburetor 3 and gathering in a lowermost portion 8 of the suction pipe 1, is guided to a fuel reservoir 4 along the flow of sucked air. In this case, air, sucked through the vent hole 5 by means of a suction negative pressure produced during operation of an engine, blows away liquid fuel, gathering in the fuel reservoir 4, in a sprayed state to promote evaporization of the fuel, and the fuel and the sir are uniformly guided in a combustion chamber.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to an intake pipe of an internal combustion engine, in particular, to atomize liquid fuel and promote vaporization during operation of the internal combustion engine [Prior Art] Conventionally, a structure for promoting vaporization is used. For example, as shown in Fig. 3, the intake pipe 1 is provided with a hot water heating passage 2 connected to the cooling system of the engine, and warm cooling water of the engine is introduced into the hot water heating passage 2. The structure is such that the inner wall of the intake pipe 1 is heated. Therefore, part of the air-fuel mixture taken in from the carburetor 3 becomes liquid fuel, but the heated intake pipe 1
The liquid fuel is atomized by receiving heat from the inner wall of the fuel tank, promoting vaporization.

[Problem that the invention seeks to solve]

However, such conventional evaporation promotion structures have a structure in which warm cooling water is passed through a part of the intake pipe to warm the inner wall of the intake pipe. The water was not warm enough to warm the intake pipe, and it was not possible to promote the vaporization of the liquid fuel in the intake pipe.

Therefore, liquid fuel is sucked into the combustion chamber, which causes black smoke, etc., and combustion is unstable, which causes the engine to have to be warmed up by setting the engine speed high. there were.

The present invention was developed with a focus on these problems, and uses an extremely simple structure to reduce the amount of liquid fuel that accumulates in the intake pipe at the same time as the cold start of the engine into the air that is sucked in by the intake negative pressure during engine operation. The purpose of this project is to atomize using the flow of water and promote vaporization to solve the above problems.

[Means for solving problems]

The present invention provides an intake pipe for an internal combustion engine, characterized in that a fuel reservoir is provided on the inner wall of the intake pipe, and a vent hole communicating with the atmosphere via an air cleaner is opened in or near the fuel reservoir.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.
In the illustrated example, the intake pipe 1 is arranged between the carburetor 3 and the engine as in the conventional example, but a fuel reservoir 4 in which liquid fuel accumulates is provided on the inner wall of the intake pipe I, and inside this fuel reservoir 4 or A small ventilation hole 5 communicating with the outside air is opened in the vicinity, a communication pipe 6 is connected to the ventilation hole 5 by a connector 7, and the other end of the communication pipe 6 is connected to the clean side of an air cleaner (not shown). It communicates with the atmosphere through.

In the figure, 8 indicates the lowest part within the intake pipe 1.

Next, to explain its operation, during a cold start of the engine and immediately after warm-up operation, a super-rich mixed gas in a normal-liquid state is supplied by the carburetor 3 to the lowest point 8 of the intake pipe l. Part of the liquid fuel that has not been drawn into the combustion chamber is collected in the combustion chamber, and this liquid fuel is guided to the fuel reservoir 4 along the flow of intake air.

On the other hand, air is sucked in from the vent hole 5 opened in or near the fuel reservoir 4 via the communication pipe 6 due to intake negative pressure during engine operation. The liquid fuel that is continuously introduced into the combustion chamber 4 is blown off into a mist, which promotes vaporization of the atomized fuel and allows the fuel to be uniformly introduced into the combustion chamber.

Further, the second illustrated example shows another embodiment of the present invention, in which a fuel reservoir is not provided on the inner wall of the intake pipe 1, and the lowest part 8 in the intake pipe 1 is made to also serve as a fuel reservoir. A vent hole 5 is opened in or near the first part 8, and the liquid fuel accumulated in the lowest part 8 at the time of starting the engine and during operation is removed from the first part 8.
It atomizes and promotes vaporization by the same action as shown in the figure.

In addition, in both the embodiments shown in FIGS. 1 and 2, it is also advantageous to connect the end of the communication pipe 6 to the air cleaner after passing through the engine crankcase instead of directly communicating with the air cleaner. Blow-by gas can be sucked from the engine's crankcase and reburned.

Further, in each of the above embodiments, explanations have been given of those without an intake pipe heating mechanism, but it goes without saying that they can be combined with an intake pipe having a conventionally known exhaust or hot water heating mechanism.

〔Effect of the invention〕

As described above, according to the present invention, a vent hole is opened in the part where liquid fuel accumulates in the intake pipe, and the liquid fuel accumulated in the engine intake pipe is blown out and atomized. Even if liquid fuel accumulates in the intake pipe during warm-up, it can be atomized and vaporization promoted, improving the fuel condition and allowing operation with a relatively lean mixture ratio. The production of black smoke is reduced, the stability of operation after startup is improved, and the warm-up speed can be maintained at a low rotational speed.

Furthermore, since the vaporization of liquid fuel in the intake pipe is promoted, fuel efficiency and output are improved even at warm temperatures, and gaseous pollutants such as Co and HC can be reduced by promoting complete combustion. Washing out of the lubricating oil due to liquid fuel flowing out into the cylinder is reduced, wear between the piston and cylinder is prevented, and at the same time, it is possible to prevent the lubricating oil from being diluted by the fuel.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the present invention, and FIG. 2 is a longitudinal cross-sectional view showing another embodiment of the present invention.
-・-Hot water heating passage, 3.--Carburizer, 4-.Fuel reservoir, 5-.-Vent hole, 6.-Series pipe, 7-.Connector,
8.-Lowest part.

Claims (1)

[Claims] 1. An intake pipe for an internal combustion engine, characterized in that a fuel reservoir is provided on the inner wall of the intake pipe, and a vent communicating with the atmosphere via an air cleaner is opened in or near the fuel reservoir. . 2. The intake pipe for an internal combustion engine according to claim 1, wherein the lowest portion of the inner wall of the intake pipe is the fuel reservoir. 3. The intake pipe for an internal combustion engine according to claim 1 or 2, wherein the vent hole communicates with the air cleaner through the engine's crankcase.