JPH0412163A - Fuel feed device for spark ignition engine - Google Patents

Abstract

PURPOSE:To facilitate the start of engine at a low temperature by providing a fuel pump on a sub-nozzle tube to supply fuel into the intake pipe of an engine in which fuel being hard to start such as alcoholic fuel is used, and driving the pump with a starter motor for starting the engine. CONSTITUTION:In a carburetor in which the extreme end of a main nozzle tube 5 is opened at the venturi part 13 formed in an intake pipe 12, a slow nozzle tube 6 is branched off from the main nozzle tube 5, and the extreme end of the slow nozzle tube 6 is opened at the closing position of a throttle valve 14, a sub-nozzle tube 15 is branched off from a float chamber 2, the outlet of the sub-nozzle tube 15 is arranged in the intake pipe 12, a fuel pump 16 is arranged on the sub-nozzle tube 15, and the fuel pump 16 is driven with a starter motor 17. At starting the engine the fuel pump 16 is driven interlocking with the starter motor 17, fuel is supplied from the sub-nozzle tube 15 into the intake pipe 12, hereby, vaporization of fuel is promoted, and good starting is secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel supply system for a spark ignition engine that uses fuel that is difficult to start, such as light oil, kerosene, and/or alcohol fuel.

[Prior Art] Conventionally, in order to improve the startability of an internal combustion engine, spark ignition engines such as gasoline engines have been provided with a check-if valve or a start-up increase mechanism in systems using a carburetor fuel supply device. , Also, in the method using a fuel injection valve,
By electronically controlling the injection valves, the amount of fuel supplied during startup is increased.

FIG. 3 shows an example of the above-mentioned starting increase mechanism.

The carburetor 1 consists of a float chamber 2, a float 3, a fuel supply pipe 4, a main nozzle pipe 5, a slow nozzle pipe 6, an air bleed pipe 7, a main jet 8, a slow jet 9, an air bleed jet 10, an idle adjustment screw 11, The tip of the main nozzle pipe 5 is opened to a venturi part 13 formed in the intake pipe 12, and a slow nozzle pipe 6 is branched from the main nozzle pipe 5.
The tip of the throttle valve 14 is opened at the closed position of the throttle valve 14 .

When the engine is started, the throttle valve 14 is in the closed position, so fuel flows from the slow nozzle pipe 6 to the intake pipe 12.
The structure is such that it is supplied internally.

[Problems to be solved by the invention] Although these measures ensure startability at room temperature, it takes time to start at low outside temperatures, and HC
There are problems such as an increase in emissive a, especially for low-volatile fuels other than gasoline such as kerosene, low cetane number fuels such as cracked light oil, or fuels that are difficult to start such as alcohol fuels. Even with conventional methods, starting at low temperatures is difficult. For example, in the case of alcohol, kerosene, etc., methods have been adopted to improve starting performance by using gasoline at the time of starting.

However, there is a problem in that a fuel tank and a carburetor for fuel with good ignitability must be added. Further, when the above-mentioned conventional start-up increase mechanism is employed, there is a problem that a sufficient flow rate cannot be secured because the slow nozzle pipe 6 is branched from the main nozzle pipe 5.

An object of the present invention is to solve the above-mentioned problem, and to reduce the temperature of the engine at low temperature without changing the design of the carburetor in a spark ignition engine that uses fuel that is difficult to start, such as kerosene, diesel oil, and/or alcohol fuel. The object of the present invention is to enable starting, shorten starting time, and reduce HC eminlon.

[Means for Solving the Problems] To this end, the fuel supply device for a spark ignition engine of the present invention provides a spark ignition engine that uses a fuel that is difficult to start, such as kerosene, light oil, and/or alcohol fuel, and a starter that starts the engine. A motor 17, a main nozzle pipe 5 that supplies the fuel to the venturi section 13 of the intake pipe 12, a sub-nozzle pipe 15 that supplies the fuel to the intake pipe, and a fuel pump 16 disposed in the sub-nozzle pipe 15. The fuel pump 16 is driven by the starter motor 17.

Note that the numbers added to the above configurations are for comparison with the drawings to facilitate understanding, and the configurations of the present invention are not limited thereby.

[Function] In the present invention, as shown in FIG. 1, for example, when the starter motor 17 rotates when the engine is started, fuel flows into the intake pipe 12 from the auxiliary nozzle pipe 15, which drives the fuel pump 16. is supplied to enable starting.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a fuel supply system for a spark ignition engine according to the present invention.
FIG. 2 is a configuration diagram showing an example.

The carburetor 1 consists of a float chamber 2, a float 3, a fuel supply pipe 4, a main nozzle pipe 5, a slow nozzle pipe 6, an air bleed pipe 7, a main jet 8, a slow jet 9, an air bleed jet 10, an idle adjustment screw 11, The tip of the main nozzle pipe 5 is opened to a venturi part 13 formed in the intake pipe 12, and a slow nozzle pipe 6 is branched from the main nozzle pipe 5.
The tip of the throttle valve 14 is opened at the closed position of the throttle valve 14 .

The above configuration is the existing carburetor explained in FIG. 3, but in the present invention, the sub nozzle pipe 15 is branched from the float chamber 2, and the outlet of the sub nozzle pipe 15 is
At the same time, a fuel pump I6 is installed in the sub nozzle pipe 15.
The fuel pump 16 is driven by a starter motor 17 that starts the engine.

To explain the operation of the present invention having the above configuration, fuel that is difficult to start, such as kerosene, diesel oil, or alcohol fuel, is supplied to the float chamber 2 from a fuel tank (not shown) to the fuel supply pipe 4, and the float 3 supplies the fuel to the float chamber 2 at a constant rate. adjusted to the amount. When the starter motor 17 rotates when starting the engine, the fuel pump 16 is driven in conjunction with this rotation. At this time, since the throttle valve 14 is in the closed position, fuel is supplied into the intake pipe 12 from the slow nozzle pipe 6, and fuel is supplied into the intake pipe 12 from the sub nozzle pipe 15. Therefore, vaporization of the fuel is promoted and starting becomes possible.

When the engine starts, the starter motor 17 stops, and in conjunction with this, the fuel pump 16 also stops. and,
As the opening degree of the throttle valve 14 increases, the negative pressure in the venturi section 13 increases, so a proportionate amount of fuel is sprayed into the intake pipe 12 from the main nozzle pipe 5.

FIG. 2 shows another embodiment of the fuel supply device of the present invention.

FIG. 1 is a block diagram showing one embodiment of a fuel supply system for an internal combustion engine according to the present invention.

The spark ignition engine 21 includes a cylinder 22 and a piston 23.
, an intake pipe 12, an exhaust pipe 24, an intake valve 25, an exhaust valve 26, and an ultrasonic atomizer 28 having an ultrasonic vibration member 27 on the intake pipe 12 side. Ultrasonic vibration member 2
An atomizing section 29 is formed at one end of the 7, and an electric/acoustic conversion element 30 is provided at the other end. In addition, the atomization section 2
As the shape of 9, a well-known shape such as a round shape or a bat shape is adopted. Further, an ignition device 32 is disposed in the combustion chamber 31 in the upper part of the cylinder 22 so as to face the piston 23 .

Then, the sub nozzle pipe 15 described in FIG. 1 is arranged so that fuel is supplied to the atomizing section 29 of the ultrasonic vibration member 27. Therefore, since the fuel is exposed to fine droplets due to the ultrasonic vibration, the startability of the engine can be further improved.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made.

For example, it goes without saying that the effects of the present invention can be achieved even without the special provision of the slow nozzle pipe 6, air bleed pipe 7, and slow jet 9.

Further, a heating device may be provided in the sub-nozzle pipe 15 to heat the fuel when starting the engine.

[Effects of the Invention] As described above, according to the present invention, in a spark ignition engine that uses fuel that is difficult to start, such as kerosene, diesel oil, and/or alcohol fuel, a fuel pump is provided in the auxiliary nozzle pipe that supplies the intake pipe. Since the fuel pump is driven by a starter motor that starts the engine, it is possible to start the engine at a low temperature, shorten the starting time, and reduce HC emin.

[Brief explanation of drawings]

FIG. 1 shows a fuel supply system for a spark ignition engine according to the present invention.
FIG. 2 is a block diagram showing another embodiment of the fuel supply system for a spark ignition engine according to the present invention, and FIG. 3 is a block diagram illustrating a conventional fuel supply system. 5... Main nozzle pipe, 12... Electric L13...
Venturi section, 14... Throttle valve, 15...
Sub-nozzle pipe, 16...Fuel pump, 17...Starter motor. Figure 1 Applicant: Tonen Corporation

Claims (2)

[Claims] (1) In spark ignition engines that use fuel that is difficult to start, such as kerosene, diesel oil, and/or alcohol fuel,
A starter motor that starts the engine, a main nozzle pipe that supplies the fuel to the venturi portion of the intake pipe, a sub-nozzle pipe that supplies the fuel to the intake pipe, and a fuel pump disposed in the sub-nozzle pipe. 1. A fuel supply device for a spark ignition engine, wherein the fuel pump is driven by the starter motor. (2) The fuel supply device for a spark ignition engine according to claim 1, wherein the sub nozzle pipe is connected to an ultrasonic atomizer.