JPH048863A - Fuel supply method of spark ignition engine - Google Patents

Abstract

PURPOSE:To enable safe driving of an engine and to reduce flue gas by providing a fuel with excellent ignitionability only from a carburetor while a throttle valve opening degree is small, and by providing a fuel with poor startability from a fuel supply valve when the throttle opening degree reaches a predetermined value. CONSTITUTION:In an air intake pipe 4 of a spark ignition engine 1, an air filter 8, a carburetor 9, a throttle valve 10 and a fuel supply valve 11 are arranged in order from the upper stream side. the carburetor 9 is constituted of a float chamber 12, a float 13, a fuel supply pipe 14, a nozzle pipe 15 and an air bypass pipe 16 for generating differential pressure, and the tip end of the nozzle pipe 15 is opened in a venturi part 17 of the intake pipe 4. At start of the engine, a fuel with excellent iginitionability such as gasoline is supplied from the carburetor while an opening degree of the throttle valve 10 is small. In the meantime, when the throttle opening degree reaches a predetermined value, a fuel with poor startability such as light oil, lamp oil or alcohol is supplied form the fuel supply valve 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for fueling a spark ignition engine using light oil, kerosene or alcohol fuel.

[Prior Art] Conventionally, spark ignition engines that use fuels with poor startability such as diesel oil, kerosene, or alcohol have poor startability, especially low-temperature startability, so fuels with good ignitability such as gasoline are used for starting. There is a known method in which the engine is started, and once the engine has warmed up sufficiently, the engine is switched from gasoline to the fuel with poor startability. In this case, two carburetors are used, one for fuel with good ignitability and one for fuel with poor startability.

[Problem to be solved by the invention] By the way, in a spark ignition engine that supplies a fuel different from gasoline, there is a problem that if the fuel necessary for the operating condition is supplied all at once before rated operation is reached, the engine will malfunction. There is. However, in the above conventional system, the carburetor supplies fuel with poor startability, so when the engine starts, as the throttle opening increases, fuel is supplied from the float chamber of the carburetor all at once, causing the engine to start. This has led to problems such as poor performance and an increase in smoke emissions.

The present invention solves the above problems, and is capable of achieving stable engine operation and reducing exhaust smoke in spark ignition engines that use fuel with poor startability such as diesel oil, kerosene, or alcohol. The purpose is to provide a method for supplying fuel to an ignition engine.

[Means for Solving the Problems] For this purpose, the fuel supply method for a spark ignition engine of the present invention provides a method for supplying fuel to a spark ignition engine using a carburetor 9 disposed in an intake pipe 4 of an engine 1.
, is provided with a throttle valve 10 and a fuel supply valve 11, and when the engine is started, while the opening degree of the throttle valve 10 is small,
A fuel with good ignitability such as gasoline is supplied only from the carburetor 9, and when the throttle opening reaches a predetermined value, a fuel with poor startability such as diesel oil, kerosene or alcohol is supplied from the fuel supply valve 11. Features.

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, for example, when starting the engine, while the opening degree of the throttle valve 10 is small, fuel with good ignitability such as gasoline is supplied from the carburetor 9 to the throttle valve as shown in line A in FIG. The opening is increased as the opening becomes larger, and when the engine starts and the throttle opening reaches a predetermined value, fuel with poor startability such as light oil, kerosene, or alcohol is supplied from the fuel supply valve 11 as shown by line B. At the same time, the supply of gasoline fuel is reduced and eventually stopped.

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

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

The spark ignition engine 1 includes a cylinder 2, a piston 3, an intake pipe 4, an exhaust pipe 5, an intake valve 6, and an exhaust valve 7. An air filter 8, a carburetor 9, a throttle valve 101, and a fuel supply valve 11 are arranged in the intake pipe 4 in this order from the upstream side.

The carburetor 9 consists of a float chamber 12, a float 13, a fuel supply pipe 14, a nozzle pipe 15, and an air bypass pipe 16 for generating a differential pressure. It is opened. A fuel with good ignitability, such as gasoline, is supplied to the float chamber 12 from a fuel pump (not shown) through the fuel supply pipe 14, and is adjusted to a constant amount by the float 13. As the opening degree of the throttle valve 10 increases, the negative pressure in the venturi section 17 increases, so that a proportionate amount of gasoline is sprayed from the nozzle pipe 15 into the intake pipe 4.

On the other hand, the fuel supply valve 11 is supplied with fuel having poor startability, such as light oil, kerosene, or alcohol, from a fuel pump (not shown).

Next, a fuel supply method for a spark ignition engine according to the present invention will be explained with reference to FIG.

When starting the engine, while the opening degree of the throttle valve 10 is small, the fuel supply from the fuel supply valve 11 is stopped, and fuel with good ignitability such as gasoline is supplied from the carburetor 9 as shown in FIG.
As shown by the line, increase as the throttle opening increases. The engine starts and the throttle opening is set to the predetermined value θ
When the fuel supply valve 11 reaches 1, a fuel with poor startability such as diesel oil, kerosene, or alcohol is supplied from the fuel supply valve 11 as shown by line B in the figure, and the supply of gasoline fuel is decreased and eventually stopped. Note that the fuel supply from the fuel supply valve 11 may be increased in stages as shown by line C in the figure.

[Effects of the Invention] As described above, according to the present invention, when the engine is started, while the throttle valve opening is small, fuel with good ignitability such as gasoline is supplied only from the carburetor, and the throttle opening is maintained at a predetermined value. When the fuel supply valve reaches this point, fuel with poor starting properties such as diesel oil, kerosene, or alcohol is supplied from the fuel supply valve.
In a spark ignition engine that uses a fuel with poor startability such as kerosene or alcohol, stable engine operation and reduction of exhaust smoke can be achieved.

[Brief explanation of drawings]

FIG. 1 shows a fuel supply method for a spark ignition engine according to the present invention.
FIG. 2 is a diagram showing the configuration of the embodiment and is a diagram for explaining the fuel supply method. 1... Spark ignition engine, 4... Intake pipe, 9...
Carburetor 10... Throttle valve, 11... Fuel injection valve. Applicant: Tonen Corporation

Claims (1)

[Claims] (1) A carburetor installed in the intake pipe of the engine,
Equipped with a throttle valve and a fuel supply valve, when the engine is started, while the throttle valve opening is small, fuel with good ignitability such as gasoline is supplied only from the carburetor, and when the throttle opening reaches a predetermined value, A fuel supply method for a spark ignition engine, characterized in that a fuel with poor startability, such as light oil, kerosene, or alcohol, is supplied from the fuel supply valve.