JPS6234942B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply device for a fuel injection engine.

Conventionally, in multi-cylinder engines, fuel injection nozzles (four in the case of a four-cylinder engine) are installed in each branch of the engine's intake manifold, and the fuel injection amount is determined according to the amount of intake air measured by an air flow meter, etc. A fuel supply system for a fuel injection engine that is controlled by a computer and injects fuel from each fuel injection nozzle is well known (see, for example, Japanese Utility Model Application No. 53-90718).

However, in the above-mentioned conventional device, each branch of the intake manifold is provided with a fuel injection nozzle, so while the distribution of fuel to each cylinder is good, the fuel cannot be atomized sufficiently. The problem was that a fuel injection nozzle was required for each cylinder, which increased costs.

Therefore, in order to deal with this problem, a fuel injection nozzle is provided in the intake passage upstream of the throttle valve, so that fuel can be distributed well to each cylinder even with a small number of fuel injection nozzles compared to the number of cylinders. In addition, it is conceivable to provide an ultrasonic diaphragm facing the tip of the fuel injection nozzle with a predetermined space therebetween to promote atomization of the fuel.

However, in this case, the flow velocity of the intake air decreases significantly as the intake air filling rate decreases, especially in the low-load operating range of the engine, so that the fuel injected from the fuel injection nozzle to the ultrasonic diaphragm is affected by the ultrasonic waves. Some of the fuel is reflected by the diaphragm and is scattered upstream from the ultrasonic diaphragm, and once the fuel is scattered upstream, it is not swept downstream due to the slow intake flow rate, but instead condenses and adheres to the inner wall of the intake passage. However, there is a problem in that the atomization of the fuel cannot be sufficiently promoted. Also,
There is also a problem in that fuel followability during transient operation such as acceleration is poor due to the condensation of the fuel on the inner wall of the intake passage.

In order to solve the above problem, it is possible to provide a bench lily section in the intake passage that increases the intake flow rate, and arrange the fuel injection nozzle and the ultrasonic diaphragm inside the bench lily section. When a sonic diaphragm is arranged, a new problem arises in that it is not possible to secure a sufficient vibrating surface area of the ultrasonic diaphragm for the injection angle of the fuel injection nozzle due to constraints on the inner diameter of the bench lily.

The present invention has been made in view of such problems, and includes a fuel injection nozzle and an ultrasonic wave that face each other while maintaining a predetermined space from the tip of the fuel injection nozzle in a vent lily section provided in the intake passage upstream of the throttle valve. In the fuel supply device for a fuel injection engine comprising a diaphragm, the bench lily portion is formed into an elongated hole shape whose long axis is substantially perpendicular to the center of fuel injection from the fuel injection nozzle. , while ensuring a sufficient vibration surface area of the ultrasonic diaphragm and ensuring good distribution of fuel to each cylinder, increasing the intake flow velocity especially during low load operation of the engine, and thus increasing the upstream flow of fuel. This prevents scattering and also sufficiently promotes fuel atomization.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

1 and 2, 1 is a multi-cylinder engine such as a four-cylinder engine, 2 is an intake manifold connected to the engine 1, and an intake passage 3 is connected upstream of the intake manifold 2. There is.
A throttle valve 4 that operates in conjunction with an accelerator pedal (not shown) is disposed in the intake passage 3, and the intake passage 3 supplies intake air metered by the throttle valve 4 over the entire operating range of the engine. It is configured as follows.

A bench lily portion 5 is provided in the intake passage 3 upstream of the throttle valve 4, and the bench lily portion 5 is formed into an elongated hole shape as shown in FIG. A fuel injection nozzle 6 and a flat ultrasonic diaphragm 7 facing the tip of the fuel injection nozzle 6 with a predetermined space are disposed on the short axis of the elongated hole of the bench lily portion 5. The sonic diaphragm 7 is arranged such that its vibration surface faces the central axis of the fuel injection nozzle 6 at a substantially right angle, and is also substantially parallel to the long axis of the elongated hole in the bench lily portion 5 in order to maximize the area of the vibration surface. It is located.

Further, the fuel injection nozzle 6 is connected to a computer 8.
A detection signal from an air flow meter 9 provided upstream of the bench lily portion 5 of the intake passage 3 is inputted to the computer 8, and an appropriate fuel injection amount is determined according to the amount of intake air measured by the air flow meter 9. The settings are controlled by a computer 8, and the settings are supplied to a fuel injection nozzle 6, which injects the fuel toward an ultrasonic diaphragm 7.

Further, the ultrasonic diaphragm 7 is connected to a ceramic vibrator 10 made of various ceramic materials such as PZT (zircon lead titanate porcelain). A high-frequency oscillator 11 is connected to vibrate the ultrasonic diaphragm 7 at a high frequency, and the high-frequency vibration turns the fuel collided with the ultrasonic diaphragm 7 from the fuel injection nozzle 6 into a fine mist. has been done.

Therefore, in the embodiment described above, when the engine is operated at low load, the intake air flows through the intake passage 3 by opening the throttle valve 4 and is throttled by the vent lily part 5 of the intake passage 3, so that the flow velocity is reduced. It will be fast. Then, an amount of liquid fuel corresponding to the amount of intake air is injected from the fuel injection nozzle 6 toward the ultrasonic diaphragm 7.
The fuel that collides with the ultrasonic diaphragm 7 due to the high frequency vibration is reflected as a fine mist. In particular, the bench lily portion 5 is formed into an elongated hole shape, the fuel injection nozzle 6 and the ultrasonic diaphragm 7 are opposed to each other on the short axis of the elongated hole of the bench lily portion 5, and the ultrasonic diaphragm 7 is
Since the vibration surface of the bench lily section 5 can be set parallel to the long axis of the elongated hole of the bench lily section 5 to maximize its vibration surface area, the fuel atomization effect of the ultrasonic diaphragm 7 can be utilized to the maximum. This makes it possible to sufficiently atomize the fuel. In addition, even if a part of the reflected fuel mist tries to scatter upstream, it is swept downstream by the high-speed intake airflow and carried away with the intake airflow, which prevents it from flying away as in the conventional case. Fuel intake passage 3 due to upstream scattering
It is possible to prevent condensation from adhering to the inner wall and sufficiently promote atomization of the fuel.

The fuel that has been sufficiently atomized in this way is throttled by the downstream throttle valve 4, thoroughly mixed with intake air, and then supplied to each cylinder of the engine 1 via the intake manifold 2. It will be evenly distributed.

On the other hand, during high-load operation of the engine, the throttle valve 4 is fully opened to supply sufficient intake air from the intake passage 3 to increase intake air filling efficiency and ensure output performance, while the fuel injection nozzle 6 The fuel injected into the intake passage 3 is sufficiently atomized by the ultrasonic diaphragm 7 and mixed with the intake air by the throttle valve 4, just as when the engine is under low load. Evenly distributed and supplied to the cylinders.

In addition, by preventing fuel from scattering upstream and promoting fuel atomization as described above, fuel followability during transient engine operations such as during acceleration is improved, improving acceleration performance, etc. be able to.

As explained above, according to the present invention, in a fuel injection type engine, it is possible to ensure good distribution of fuel to each cylinder even with a small number of fuel injection nozzles compared to the number of cylinders, and to reduce the load of the engine. During operation, the high intake flow rate of the bench lily prevents the upstream scattering of fuel due to the ultrasonic diaphragm and promotes fuel atomization. By forming the hole in the shape of a long hole with its long axis in a substantially orthogonal direction, it is possible to secure a sufficient vibration surface area of the ultrasonic diaphragm, thereby maximizing the atomization of fuel by the ultrasonic diaphragm. It is something that can be done.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 1 is a schematic longitudinal cross-sectional view of the whole, and FIG. 2 is a cross-sectional view of the embodiment of the present invention.
FIG. DESCRIPTION OF SYMBOLS 1... Engine, 2... Intake manifold, 3... Intake passage, 4... Throttle valve, 5... Bench lily part, 6... Fuel injection nozzle, 7... Ultrasonic diaphragm, 8
...Computer, 9...Air flow meter, 10...
Ceramic resonator, 11...high frequency oscillator.

Claims (1)

[Claims] 1. Fuel supply for a fuel injection engine, which is equipped with a fuel injection nozzle in a bench lily provided in an intake passage upstream of a throttle valve, and an ultrasonic diaphragm facing the tip of the fuel injection nozzle with a predetermined space therebetween. A fuel supply device for a fuel injection type engine, wherein the bench lily portion is formed in the shape of an elongated hole whose long axis is substantially perpendicular to the center of fuel injection from the fuel injection nozzle.