JPH0412159A - Fuel supply device of spark ignition engine - Google Patents

Abstract

PURPOSE:To facilitate low temperature start by providing a main nozzle pipe for supplying a fuel such as an alcohol fuel which is hard to start to a venturi part and an auxiliary nozzle pipe for supplying the same fuel to the position opposite to an intake valve and by providing an opening/closing valve and a heating device at this nozzle pipe. CONSTITUTION:The tip end of a main nozzle pipe 5 is opened at a venturi part 13 formed at an intake pipe 12, a slow nozzle pipe 6 is branched from this main nozzle pipe 5, and in a carburetor 1 where the tip end of this slow nozzle pipe 6 is opened at the closed position of a throttle valve 14, an auxiliary nozzle pipe 15 is branched from a float chamber 2, an outlet of the auxiliary nozzle pipe 15 is arranged so that it is opposed to an intake valve 16, and an opening/closing valve 17 constituted by an electromagnetic valve are arranged with a heating device 19 such as an electric motor at the auxiliary nozzle pipe 15. And at start of an engine, the opening/closing valve 17 is opened and electric current is supplied to the heating device 19, a fuel supplies a heated fuel from the auxiliary nozzle pipe 15 to the intake valve 16 so as to promote carburetion of the fuel which is hard to start, and start is facilitated.

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 a fuel that is difficult to start, such as light oil, kerosene, or alcohol fuel.

[Prior Art] Conventionally, in order to improve the startability of internal combustion engines, spark ignition engines such as gasoline engines have been provided with a choke valve or a starting increase mechanism in systems using a carburetor fuel supply device, and In systems using fuel injection valves, the amount of fuel supplied at startup is increased by electronically controlling the injection valves.

FIG. 2 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.
[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 increased emissions, and the above conventional Depending on the method, starting at low temperatures is difficult; for example, in the case of alcohol, kerosene, etc., a method is adopted in which gasoline is used at the time of starting to improve starting performance.

However, there is a problem in that a fuel tank and a carburetor for fuel with good ignitability must be added. In addition, when the above-mentioned conventional start-up increase mechanism is adopted, since the slow nozzle pipe 6 is branched from the main nozzle pipe 5, a sufficient flow rate cannot be secured, and
Even if an attempt is made to heat the fuel, there is a problem in that it is difficult to provide a heating device to an existing carburetor.

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 purpose is to enable starting, shorten starting time, and reduce HC emissions.

[Means for Solving the Problems] To this end, the fuel supply device for a spark ignition engine of the present invention supplies the fuel to the intake pipe in a spark ignition engine that uses fuel that is difficult to start, such as kerosene, light oil, and/or alcohol fuel. 12, a main nozzle pipe 5 that supplies the fuel to a venturi section 13, a sub-nozzle pipe 15 that supplies the fuel to a position facing the intake valve 16, an on-off valve 17 and a heating device 19 disposed in the sub-nozzle pipe 15. When starting the engine, the opening/closing valve 17 is opened and the heating device 19 is opened.
It is characterized by operating.

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.

[Operations] In the present invention, as shown in FIG. 1, for example, when the engine is started, the on-off valve 17 is opened and the heating device 19 is energized. At this time, the fuel from the auxiliary nozzle pipe 15 is heated and supplied to the intake valve 16, which promotes vaporization of the fuel and enables starting.

[Example code] 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. 2, 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
The sub nozzle pipe 15 is provided with an on-off valve 17 made of a solenoid valve and a heating device 19 such as an electric heater.

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 engine is started, the on-off valve 17 opens and the heating device 19 is energized. At this time, since the throttle valve 14 is in the closed position, fuel is supplied from the slow nozzle pipe 6 into the intake pipe 12, and fuel from the sub nozzle pipe 15 is heated and supplied to the intake valve 16. Therefore,
Fuel vaporization is promoted and starting becomes possible.

When the engine starts, the on-off valve 17 closes and the heating device 19 is turned off. Then, as the opening degree of the throttle valve 14 increases, the negative pressure in the venturi section 13 increases, so that a proportionate amount of fuel is sprayed into the intake pipe 12 from the main nozzle pipe 5.

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

For example, in the above embodiment, the on-off valve 17 is electrically switched as a solenoid valve, but the on-off valve 17 and the throttle valve 14 may be linked and switched in conjunction with the opening degree of the on-off valve 17 and the throttle valve 14. .

Furthermore, 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.

[Effects of the Invention] As described above, according to the present invention, a fuel heating supply device can be installed 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. By simply adding it, it is possible to start the engine at a low temperature, shorten the starting time, and reduce HC emissions.

[Brief explanation of the drawing]

FIG. 1 shows a fuel supply system for a spark ignition engine according to the present invention.
FIG. 2 is a block diagram illustrating a conventional fuel supply device. 5... Main nozzle pipe, 12... Branch trachea, 13...
・Venturi part, 14... Throttle valve, 15.
... Sub-nozzle pipe, 16... Intake valve, 17... Opening/closing valve, 19... Heating device. Applicant Hiroki Shirai (7 others), Patent Attorney for Tonen Co., Ltd. Figure 1

Claims (1)

[Claims] (1) In spark ignition engines that use fuel that is difficult to start, such as kerosene, diesel oil, and/or alcohol fuel,
A main nozzle pipe that supplies the fuel to a venturi portion of the intake pipe, a sub-nozzle pipe that supplies the fuel to a position facing the intake valve, and an on-off valve and a heating device disposed in the sub-nozzle pipe. A fuel supply system for a spark ignition engine, characterized in that when the engine is started, the on-off valve is opened and a heating device is operated.