JPH03172576A - Fuel supply 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 atomizing fuel after being subjected to ultrasonic vibration and simultaneously making a gas temperature in a combustion chamber go up by means of lowering the extent of exhaust efficiency, at a time when an internal combustion engine is started. CONSTITUTION:When an internal combustion engine 1 is started, a vibrator horn 24 is subjected to ultrasonic vibration with an ultrasonic wave generating means 22, and 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 port 8 with the opening of an intake valve 12. An air-fuel mixture is thereby easily ignited and combusted. Simultaneously with this, a throttle valve 19 is operated in the opening direction and exhaust flow in an exhaust manifold 17 is restricted, thereby increasing a residual gas in the combustion chamber 6. 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.

Description

[Detailed Description of the Invention] No. 1 The present invention relates to a fuel supply device for an internal combustion engine such as a gasoline engine or a diesel engine.
In particular, it improves the low-temperature startability of internal combustion engines, and also has low volatility and
The present invention relates to a fuel supply system for an internal combustion engine at the time of starting to enable starting with low cetane number fuel.

[Higashi Shiji I] 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 type fuel supply system, or an injection type fuel supply system. When a fuel supply device is used, each injection valve is electronically controlled to increase the amount of fuel supplied during startup. On the other hand, compression ignition engines such as diesel engines use starting aids such as glow plugs.

Although these measures that the company is trying to take ensure the startability of internal combustion engines, there are problems such as it takes time to start at low temperatures and an increase in HC emissions, especially in diesel engines. White smoke is 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 system for an internal combustion engine that enables starting with a low-volatility fuel such as kerosene or a low cetane number fuel such as cracked light oil.

Another object of the present invention is to provide a fuel supply system for an internal combustion engine that improves the cold start limit of alcohol fuels.

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 device for an internal combustion engine that enables startability, that is, shortening of starting time and reduction of HC emissions, even when using light oil.

The above-mentioned aspects for achieving this are achieved by the fuel supply device for an internal combustion engine according to the present invention. In summary, the present invention provides an ultrasonic atomizer for atomizing supplied fuel at the time of starting an internal combustion engine, and an ultrasonic atomizer for atomizing fuel supplied to a combustion chamber and facilitating ignition by promoting evaporation of the atomized fuel supplied to a combustion chamber. This fuel supply device for an internal combustion engine is characterized in that it has an exhaust throttle mechanism that controls the exhaust system in a direction that reduces exhaust efficiency during startup.

Preferably, the exhaust throttle mechanism is a throttle valve disposed on the exhaust manifold to adjust the exhaust flow rate of the exhaust manifold, or alternatively, the exhaust throttle mechanism is a throttle valve disposed on the exhaust manifold to adjust the exhaust flow rate of the exhaust manifold. The exhaust gas is provided with a bypass line that restricts the exhaust gas flow through the bypass line during startup.

Next, the fuel supply system 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 IO, 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 may be a commonly used one, and 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. .

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. A throttling mechanism is provided in the exhaust system, and at the time of startup, the throttling mechanism restricts the flow rate of exhaust gas flowing through the exhaust system, reducing exhaust efficiency, thereby increasing the residual gas in the combustion chamber 6, and reducing the residual gas. This is to quickly raise the gas temperature in the combustion chamber 6 to a predetermined temperature necessary for evaporation of the atomized fuel.

A throttle mechanism for this purpose is achieved by providing a throttle valve 19 such as a butterfly valve in an exhaust manifold 17 communicating with an exhaust hole, as shown in FIG. That is, at the time of startup, the throttle valve 19 is operated in a direction that reduces exhaust efficiency, restricting the exhaust flow rate of the exhaust manifold 17, thereby increasing the residual gas in the combustion chamber 6, and using this residual gas to combust. The gas temperature in the chamber 6 is quickly raised 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.

According to the results of research experiments conducted by the present inventors, the restriction of the exhaust flow rate by the throttle valve 19 during startup is 20 to 20% of the normal exhaust flow rate.
Good results were obtained by reducing the amount to about 80%.

Alternatively, as shown in FIG.
0, and the exhaust gas can be configured to flow through the bypass pipe 40 using the switching valve 42 at the time of startup. The bypass line 40 is provided with, for example, a restriction orifice 44, and has the function of normally comparing and restricting the exhaust flow rate from the combustion chamber. Even with such a configuration, the same effects as described above can be obtained.

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 inside the combustion chamber is sufficiently increased. Due to this, together with the atomization effect of the supplied fuel, the evaporation and ignition of the fuel are significantly promoted. becomes possible.

(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 illustrating an embodiment of the fuel supply device of the present invention. FIG. 2 is a cross-sectional view of an ultrasonic atomizer used in the practice of the present invention. FIG. 3 is a schematic sectional view of a gasoline engine showing another embodiment of the present invention. 1: Gasoline engine 6: Combustion chamber 12: Intake valve 14: Exhaust valve 16: Intake manifold 17: Exhaust manifold 19: Throttle valve 20: Ultrasonic atomizer 30: Injector 40: Bypass pipe 1 Procedural amendment letter to district ( method) % formula % ()

Claims (1)

[Claims] 1) An ultrasonic atomizer for atomizing supplied fuel at least when starting an internal combustion engine, and for promoting evaporation of the atomized fuel supplied to the combustion chamber and facilitating ignition. 1. A fuel supply device for an internal combustion engine, comprising: an exhaust throttle mechanism that controls the exhaust system in a direction that reduces exhaust efficiency during startup. 2) Claim 1, wherein the exhaust throttle mechanism is a throttle valve disposed in the exhaust manifold to adjust the exhaust flow rate of the exhaust manifold.
Fuel supply device for the internal combustion engine described. 3) The fuel supply for an internal combustion engine according to claim 1, wherein the exhaust throttle mechanism has a bypass pipe that is attached to the exhaust manifold and limits the flow rate of the exhaust gas, and the exhaust gas flows through the bypass pipe during startup. Device.