JPS6263162A - Carburetor for methanol fuel - Google Patents

Abstract

PURPOSE:To simply and certainly start an engine at low temperature by using gasoline as auxiliary fuel and supplying the mixed gas of methanol, gasoline, and air particularly in the case when the engine is started at low temperature. CONSTITUTION:When an engine is started by closing a choke valve 16 at low temperature, the negative pressure of an intake manifold acts to the main nozzle 30 of a main fuel mixer 12, and methanol fuel is jetted the engine. At this time, the negative pressure acts also to the nozzle 64 opened at the venturi part 62 of a gasoline mixer 50 at the same time. Therefore, the gasoline in an auxiliary float chamber 52 is jetted into the venturi part 62, and mixed with the air passing through an intake passage 60, and the gasoline mixed gas is formed, and supplied into the mixed gas passage part between a choke valve 20 and the venturi part 18 of the main fuel mixer 12 through a passage 66. Therefore, the engine can be started certainly at low temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a vaporizer that uses methanol as a fuel for an internal combustion engine, and particularly to a vaporizer for methanol fuel that can facilitate low-temperature starting.

[Prior art] Methanol, or methyl alcohol, synthesized from hydrogen and carbon oxide produced by reforming natural gas or gasifying coal, has a high octane number and is highly compressible as a fuel for internal combustion plants. It has been developed as a device that can achieve high output power and high thermal efficiency, and is capable of high power ratio or high supercharging.

However, methanol has a large heat of vaporization, low vapor pressure, and has a single boiling point. Difficult to start.

[Object of the invention] Considering the problems mentioned above, the main object of this invention is to:
It is an object of the present invention to provide a methanol fuel vaporizer which supplies an air-fuel mixture to an engine mainly using methanol as fuel, and which can effectively start the engine at a low temperature.

Another object of the invention is to provide a methanol fuel vaporizer that uses gasoline as an auxiliary fuel and supplies a methanol-gasoline-air mixture, especially during cold engine starts.

[Configuration of the Invention] The methanol fuel vaporizer of the present invention will be explained with reference to the accompanying drawings. As shown in the drawings, the methanol fuel vaporizer 10 of the present invention consists of a main fuel mixer 12 exclusively for mixing methanol with air and a gasoline mixer 50 for supplying gasoline as an auxiliary fuel.

The structure of the main fuel mixer 12 is exactly the same as that of a carburetor commonly used in conventional gasoline engines, and a choke valve 16 is provided adjacent to the upstream end of the intake passage 14. A venturi portion 18 is formed in the center, and a throttle valve 20 is provided at the lower end of the intake passage 14.

A float chamber ventilation pipe 70 is provided which opens into the intake passage 14 on the upstream side of the choke valve 1G from the upper part of the float chamber 22 that accommodates methanol. Methanol in the float chamber 22 is supplied into the intake passage 14 through a main jet 26 and a main fuel passage 28 through a main nozzle 30 that opens into the venturi section 18. Further, the methanol in the float chamber 22 passes through the main jet 2G, and then passes through a low-speed fuel passage 32 that branches from the main fuel passage 28, and then passes through a bypass boat 32 that is close to the throttle valve 20 and opens at the lower end of the intake passage 14. and the idle boat 34.

As mentioned above, the structure of the main fuel mixer 12 described above is conventional and the associated configurations are well known to those skilled in the art, so the details thereof will be omitted.

According to the present invention, the main fuel mixer 12 described above is combined with the gasoline mixer 50. The gasoline mixer 50 includes an auxiliary float chamber 52 for containing gasoline, the gasoline in the auxiliary float chamber 52 being directed by a second main jet 54 to an auxiliary fuel passage 58 having an air jet 56. The auxiliary fuel passage 58 terminates in a nozzle 64 that opens into a venturi section 62 of an intake passage 60 of the gasoline mixer 50, so that the gasoline in the auxiliary float iso can be injected into the venturi section 62 and mixed with intake air. The downstream side of the venturi part 62 of the intake passage 60 of the gasoline mixer 50 is connected to the part of the intake passage 14 on the downstream side of the venturi part 18 of the main fuel mixer 12 for methanol and the upstream side of the throttle valve 20 by a passage 6G. It is.

[Operations and Effects of the Invention 1] Since the methanol fuel carburetor 10 of the present invention is configured as described above, when the engine is started with the choke valve 16 closed at low temperature, the engine is The intake manifold negative pressure acts on the main nozzle 30 of the main fuel mixer 12, methanol fuel is injected from the main nozzle 30, and the methanol mixture is supplied to the engine. However, since methanol has a smaller stoichiometric air-fuel ratio than gasoline, it is difficult to start the engine at a low temperature using the methanol mixture from the main fuel mixer 12.

However, according to the present invention, the aforementioned manifold negative pressure caused by starting the engine simultaneously acts on the nozzle 64 opening into the venturi portion 62 of the gasoline mixer 50.

Therefore, the gasoline in the auxiliary float chamber 52 flows into the nozzle 6.
4 into the venturi section 62, mixes with air passing through the intake passage 60 to form a gasoline mixture, and passes through the passage 6G to the venturi section 18 of the main fuel mixer 12 and the choke valve 2.
It is supplied to the intake passage section between the Therefore, the air-fuel mixture sent from the main fuel mixer 12 to the engine intake manifold can be a mixture of methanol, gasoline, and air, and the air-fuel mixture has an air-fuel ratio within the flammable range required for low-temperature starting of the engine. can be supplied.

According to the present invention, due to the above-described effects, methanol fuel can be mainly used, and even when the engine is started at a low temperature, the engine can be operated without causing starting difficulties as in the conventional case.

[Brief explanation of drawings]

The drawing is a schematic cross-sectional view illustrating the structure of a methanol fuel vaporizer according to the present invention. The main reference numbers in the drawings are listed below. 10... Methanol fuel vaporizer 12...
Main fuel mixer 14 Intake passage 1G Choke valve 18 Venturi section 20 Throttle valve 22 Float Chamber 26...Main jet 30...Main nozzle 50...Gasoline mixer 52...Auxiliary float chamber 54...Second main Jet 60... Intake passage G2... Venturi section 64... Nozzle 66... Passage idiot 1 person

Claims (1)

[Scope of Claims] A first intake passage having a choke valve, a venturi section, and a throttle valve, a float chamber containing methanol, and a main fuel leading from the float chamber to a main nozzle opening into the venturi section. a main fuel mixer comprising a passage; an auxiliary float chamber for storing gasoline; a second intake passage having a venturi section; and an auxiliary fuel for guiding gasoline from the auxiliary float chamber to the venturi section of the second intake passage. a passage opening into a portion of the first intake passage between the venturi section of the main fuel mixer and the throttle valve, the second intake passage of the gasoline mixer; A methanol fuel vaporizer characterized in that the downstream side of the venturi section is connected to the venturi section of the methanol fuel vaporizer.