JPH03172575A - Fuel feeding method and device for internal combustion engine - Google Patents

Abstract

PURPOSE:To excellently perform the ignition and combustion of an air-fuel mixture as well as to improve the extent of cold startability by adopting such a means that atomizes fuel after being subjected to ultrasonic vibration and simultaneously makes a gas temperature go up by increasing a residual gas in a combustion chamber and so on, at the starting of an internal combustion engine. CONSTITUTION:When an internal combustion engine 1 is started, a vibrator horn 24 is subjected to ultrasonic vibration by an ultrasonic wave generating means 22. Fuel is injected to this vibrator horn 24 from an injector 30, through which this fuel is atomized. Then this atomized fuel spray is mixed with air flowing in an intake manifold 16, and it is fed to the inside of a combustion chamber 6 through an intake part 8 with the opening of an intake valve 12. An air-fuel mixture is thereby easily ignited and composited. Simultaneously with this, valve timing of an exhaust valve 14 is controlled in the direction of lowering the extent of exhaust efficiency, whereby a residual gas in the combustion chamber 6 is increased. With this constitution, a gas temperature in the combustion chamber 6 is quickly raised to the specified temperature necessary for evaporation of the atomized fuel with a simple and inexpensive structure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply method and a fuel supply device for internal combustion engines such as gasoline engines and diesel engines. The present invention relates to a fuel supply method and a fuel supply device for an internal combustion engine at the time of startup to enable startup using low-cetane fuel.

Conventionally, in order to improve the startability of internal combustion engines, spark ignition engines such as gasoline engines use an accelerator pump when using a carburetor fuel supply system, or If an injection fuel supply system is used, each injection valve is electronically controlled to increase the amount of fuel supplied at startup.In addition, in compression ignition engines such as diesel engines, glow plugs, etc. Auxiliary equipment is used.

Although these measures ensure the startability of internal combustion engines, there are problems such as it takes time to start at low temperatures and increases HC emissions, especially in diesel engines. white smoke has become a big problem.

Furthermore, today, in addition to conventional gasoline and diesel oil, low-volatile fuels such as kerosene and alcohol fuels are used as fuels for internal combustion engines, and low-cetane fuels such as cracked diesel oil are used as fuels for diesel engines. It is desirable to use high-quality fuel.

However, according to the results of research experiments conducted by the present inventors,
It has been found that, depending on the conventional starting method described above, it is difficult to start the engine when low volatility fuel or low cetane number fuel is used as fuel.

As a solution to this problem, attempts have been made to use ultrasonic injection valves to atomize the supplied fuel and improve fuel evaporation and ignition. Although this generally improves startability, for example, the low temperature starting limit of alcohol fuels, particularly methanol, is partially improved, it is difficult to start kerosene and other low volatility, low cetane number fuels.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fuel supply method and a fuel supply apparatus for an internal combustion engine that enable starting of a low-volatility fuel such as kerosene or a low cetane number fuel such as cracked gas oil.

Another object of the present invention is to provide a fuel supply method and a fuel supply apparatus for an internal combustion engine that improve the cold start limit of alcohol fuel.

Still another object of the present invention is to use ordinary gasoline as fuel;
An object of the present invention is to provide a fuel supply method and a fuel supply device for an internal combustion engine that enable shortening of startability, that is, shortening of starting time, and reduction of HC emissions even when using light oil.

The above-mentioned aspects of the invention are achieved by the fuel supply method and fuel supply device for an internal combustion engine according to the present invention. To summarize, the present invention provides a method for atomizing supplied fuel using ultrasonic vibration and supplying it to a combustion chamber when starting an internal combustion engine, and promoting evaporation of the atomized fuel within the combustion chamber to facilitate ignition. This is a fuel supply method for an internal combustion engine, which is characterized by increasing the gas temperature within a combustion chamber.

The method of the present invention includes an ultrasonic atomizer for atomizing supplied fuel at least when starting an internal combustion engine, and an ultrasonic atomizer for promoting evaporation of the atomized fuel supplied to a combustion chamber to facilitate ignition. The present invention is suitably implemented in a fuel supply device characterized in that it has a valve control means for controlling an exhaust valve of a combustion chamber in a direction that reduces exhaust efficiency at the time of startup. Preferably, the valve control means is a valve timing adjustment mechanism that adjusts the valve timing of the exhaust valve, or two exhaust valves with different valve timings are provided, and only one exhaust valve is open at the time of startup. The valve control mechanism is said to be

1 Blood 1 Next, the fuel supply method and fuel supply device for an internal combustion engine according to the present invention will be explained in more detail with reference to the drawings.

FIG. 1 shows a part of a conventional gasoline engine 1 in which the present invention can be preferably implemented. According to this embodiment,
A combustion chamber 6 is formed by the cylinder 2 and the piston 4, and the combustion chamber 6 is provided with an intake hole 8 and an exhaust hole 10. or,
An intake valve 12 and an exhaust valve 14 are provided in the intake hole 8 and the exhaust hole 10, respectively, and an ultrasonic atomizer 20 is provided in an intake manifold 16 communicating with the intake hole 8.

In this embodiment, the ultrasonic atomizer 20 is, for example, a bolted Langevin transducer (BLT), as illustrated in FIG.
The ultrasonic vibration generating means 22 has an ultrasonic vibration generating means 22, and a vibrator horn 24 connected to the ultrasonic vibration generating means 22. In this embodiment, the vibrator horn 24 is attached to the intake manifold 16 via a housing 26. Vibrator horn 2
The tip portion 28 of No. 4 can have any shape, such as an enlarged diameter shape, a hollow truncated conical shape, or a trumpet shape.

Further, in this embodiment, the housing 26 includes an ultrasonic atomizer 2.
An injector 30 for supplying fuel to the ultrasonic atomizer 20 is installed adjacent to the ultrasonic atomizer 20 . Fuel from the injector 30 is supplied to the outer peripheral surface of the tip of the vibrator horn 24 of the ultrasonic atomizer 20 through a fuel supply passage 32 formed in the housing 26 . The injector 30 is a commonly used one (its structure and operation are well known to those skilled in the art, so further explanation will be omitted).

In the above configuration, when gasoline is injected from the injector 30 into the vibrator horn 24 which is ultrasonically vibrated by the ultrasonic generating means 22 at least when starting the engine, the gasoline is atomized by the vibrator horn 24. , is injected into the intake manifold 16. The atomized gasoline atomized body is mixed with the air flow flowing in the intake manifold 16, and is drawn into the combustion chamber 6 through the intake hole 8 with the intake valve 12 opened.

In the present invention, the fuel needs to be atomized by the ultrasonic atomizer 20 to an average particle size of 60 μm or less.

The ultrasonic atomizer 20 and injector 30 may be a starting-only fuel supply means that operates only when the engine is started (or may operate as a fuel supply means even after the engine is started). good.

Furthermore, according to the present invention, the amount of gasoline atomized into the combustion chamber 6 is small (at the time of starting the engine,
It is quickly evaporated within the combustion chamber 6 and brought into a state where ignition is easy.

As a means to quickly evaporate the atomized fuel in the combustion chamber 6 and facilitate ignition, it is possible to arrange a heater (not shown) in the combustion chamber 6, but the most preferable method is as follows. At the time of startup, the exhaust valve 14 is controlled in a direction that reduces exhaust efficiency to increase residual gas in the combustion chamber 6,
This residual gas is used to quickly raise the gas temperature within the combustion chamber 6 to a predetermined temperature required for evaporation of the atomized fuel.

As a valve control means for the exhaust valve 14 for this purpose, there is a method of adjusting the valve timing of the exhaust valve 14. That is, a valve timing adjustment mechanism is provided, and at the time of startup, the valve timing adjustment mechanism is operated to control the valve timing of the exhaust valve 14 in a direction that reduces exhaust efficiency, increasing the residual gas in the combustion chamber 6, This residual gas quickly raises the gas temperature in the combustion chamber 6 to a high temperature. Compared to a method in which a heater is disposed within the combustion chamber, this method can raise the temperature in a shorter time and can be achieved with a relatively inexpensive structure. Although various structures can be conceived as the valve timing adjustment mechanism, variable valve timing/lift mechanisms for intake and exhaust valves that have been put into practical use in recent years and are commercially available can be used.

According to the results of research experiments conducted by the present inventors, the valve timing of the exhaust valve 14 has a longer exhaust valve closing time than usual.
It has been found that the present invention can be suitably implemented by advancing the crank angle by ~5° CA.

As a valve control means for such an exhaust valve 14, in addition to the above-mentioned valve timing adjustment mechanism, for example, two exhaust valves with different valve timings are provided, and only one exhaust valve is opened at the time of startup to improve exhaust efficiency. It is also possible to employ a valve control mechanism that reduces the

As described above, according to the present invention, when starting an internal combustion engine, the fuel supplied to the combustion chamber is atomized by ultrasonic vibration, and the gas temperature within the combustion chamber is sufficiently raised. Due to this, the evaporation and ignition of the supplied fuel are significantly promoted, together with the atomization effect. It is now possible to start.

(2) The low temperature starting limit of alcohol fuel is improved.

(3) Even when ordinary gasoline or light oil is used as fuel, it is possible to improve startability, that is, to shorten the starting time and to reduce HC emissions.

It has the following effects.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a gasoline engine for explaining the fuel supply method of the present invention. FIG. 2 is a cross-sectional view of an ultrasonic atomizer used in the practice of the present invention. 1: Gasoline engine 6: Combustion chamber 12: Intake valve 14: Exhaust valve 16, intake manifold 20: Ultrasonic atomizer 0: Injector

Claims (1)

[Claims] 1) At the time of starting an internal combustion engine, the supplied fuel is atomized by ultrasonic vibration and supplied to the combustion chamber, and the evaporation of the atomized fuel within the combustion chamber is promoted to facilitate ignition. A fuel supply method for an internal combustion engine, characterized by increasing the gas temperature in a combustion chamber. 2) An ultrasonic atomizer for atomizing the supplied fuel at least at the time of starting the internal combustion engine, and an ultrasonic atomizer for atomizing the supplied fuel at least at the time of starting the internal combustion engine, and an ultrasonic atomizer for atomizing the supplied fuel at least at the time of starting the internal combustion engine. 1. A fuel supply device for an internal combustion engine, comprising valve control means for controlling an exhaust valve of a combustion chamber in a direction that reduces efficiency. 3) The fuel supply system for an internal combustion engine according to claim 2, wherein the valve control means is a valve timing adjustment mechanism that adjusts the valve timing of the exhaust valve. 4) The fuel supply system for an internal combustion engine according to claim 2, wherein the valve control means is a valve control mechanism that provides two exhaust valves with different valve timings and opens only one of the exhaust valves during startup.