JPH0450472A - Fuel jet device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve atomization of fuel while preventing fuel mists from being mixed with each other by providing jet ports to jet fuel in two different directions, and air jet ports to jet air between them to separate the fuel mists from each other. CONSTITUTION:Jet ports 4a, 4b for jetting fuel in two different directions and air jet ports 8a, 8b for jetting air between them to separate fuel mists form each other are provided. Air for changing jetted fuel into fine grains is jetted from the air jet ports 8a, 8b to be inserted between the fuel mists jetted in the different directions from the two jet ports 4a, 4b. While the two flows of fuel mists are separated from each other, therefore, the fuel can be changed into fine grains.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to improvements in fuel injection devices for internal combustion engines.

(Prior art) When a fuel injection valve is attached to the intake boat of an internal combustion engine and a mixture of premixed injected fuel and air is supplied to the engine, the atomization and atomization state of the injected fuel greatly affects the combustion characteristics. It's coming.

Therefore, many fuel injection valves have been proposed in which air (assist air) is injected together with fuel from a fuel injection valve, and collision with the assist air atomizes the fuel and improves atomization.

By the way, in order to increase the speed and output of the engine, two parts are installed in the combustion chamber.
When equipped with two intake valves to improve intake efficiency, it is necessary to distribute fuel evenly from the fuel injection valve installed on the intake boat toward the two intake valves.
Japanese Patent No. 61461 proposes a fuel injection valve that separates fuel spray into two directions to form tail streams of fuel spray.

By injecting fuel from two nozzles (boats),
The direction of the fuel is distributed equally to the two intake valves, but at the same time, in order to atomize the injected fuel, it is mixed with assist air in a mixing chamber before being ejected from the two nozzles.

(Problem to be Solved by the Invention) However, if fuel is mixed with assist air before it is ejected from the nozzle, most of the fuel adheres to the nozzle wall surface when passing through the nozzle and tends to form a wall flow, causing the injection Although the fuel could be separated, problems remained with the atomization and atomization characteristics of the fuel.

Therefore, from the point of view of atomizing the injected fuel and improving the atomization characteristics, as stated in Japanese Utility Model Application No. 1-66471,
It can be said that injecting assist air from around the fuel immediately after it is ejected from the nozzle is more effective since it does not adhere to the nozzle wall.

However, in this case, since the assist air is jetted out in a swirling manner from around the fuel spray, it is difficult to divide the fuel injection direction into two, making it impossible to distribute the fuel evenly toward the two intake valves.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fuel injection device between internal combustion engines that improves atomization and atomization without impairing the separation of fuel spray.

(Means for Solving the Problems) The present invention provides a fuel injection device for an internal combustion engine that injects high-velocity air into fuel immediately after injection from a nozzle. and an air jet a for jetting air between them so as to separate them.

(Operation) Air is injected to atomize the injected fuel between the fuel sprays ejected in different directions from the two nozzles, separating the two sprays left and right and atomizing the fuel. We aim to

(Example) Embodiments of the present invention will be described below based on the drawings.

As shown in FIGS. 1 and 2, the fuel injection valve is provided with an injection plate 3 located at the tip of an injection nozzle 2 in the center of an injector body 1, and this injection plate 3 has a plurality of injection ports 4a, 4b is formed.

The two injection ports 4a and 4b are formed so as to direct the fuel spray in two directions different by 18 degrees at a predetermined inclination angle to the injection nozzle axis and in a plane perpendicular to the axis. However, these are cases where fuel is injected so as to face two intake valves, and the number of nozzles can be further increased as necessary. Note that the actual fuel spray spreads in a conical shape with a predetermined injection angle, as shown by the shaded area.

An adapter 5 is attached to the tip of the injector body 1, and air from an air passage 7 is introduced into an annular air gear gallery 6 formed inside the adapter 5.

A pair of main air nozzles 8a, 8b and two auxiliary air nozzles 9m, 9b are formed in the inner circumferential wall 10 of the adapter 5 surrounding the injection nozzle 2, and air from the air gear gallery 6 is jetted out.

The main air nozzles 8m and 8b are arranged at positions facing each other, located between the two fuel sprays, and set to eject air in a direction perpendicular to the fuel spray direction. However, since the main air nozzles 8a and 8b eject air obliquely toward the center of the surrounding air gear gallery 6, the ejected air from each other passes through the center line of the fuel injection nozzle 2 so as to intersect with each other. It separates the fuel spray from each other and promotes atomization and atomization through collision with the fuel.

The auxiliary air nozzles 9m and 9b are located on the left and right sides of each main air nozzle 8a and 8b, and the air flow ejected from these suppresses the spread of the spray angle of the fuel spray, while atomizing it by collision with the fuel. , increase atomization.

As shown in FIG. 3, this fuel injector 15 is attached to an intake manifold 16 and injects fuel from an intake boat 17 toward an intake valve 18.

The air passage 7 branches from a position upstream of the intake throttle valve 19 and downstream of the air flow meter 20, and allows air to flow according to the pressure difference (intake negative pressure) between the upstream and downstream sides of the intake throttle valve 19.
Note that the air flowing through the intake passage 21 and the air flowing through the air passage 7 meet downstream of the fuel injector 15, and all of these are measured by the air flow meter 2o, so the air-fuel ratio of the air-fuel mixture is equal to that of the assist air. Note that 22 is a valve that controls the flow rate of the air passage 7, and controls the flow rate of assist air based on various conditions such as engine speed, suction negative pressure, and cooling water temperature.

The structure is as described above, and the operation will be explained as follows.
Fuel is injected from the fuel injection nozzle 2 in synchronization with the engine speed, and air is sucked from the air gear gallery 6 in accordance with the negative suction pressure acting on the intake boat 17.

The injected fuel is separated to the left and right by the injection ports 4a and 4b of the injection plate 3, and each spreads conically toward the intake valve 18 (two intake valves) at a predetermined injection angle.

High-speed assist air is ejected from main and sub-air nozzles 8a, 8b and 9a, 9b arranged to surround these nozzles 4a, 4b. Among them, the air ejected from the main air nozzles 8a and 8b enters between the left and right fuel sprays, and while separating the left and right sprays, the high-speed jets promote atomization and atomization of the fuel.

At the same time, assist air is ejected from the auxiliary air nozzles 9a and 9b from the center side of the fuel injection nozzle 2 so as to suppress the spread of the spray angle and promote atomization and atomization with high-speed jets. .

Since the fuel spray collides with high-speed assist air after exiting the nozzles 4m and 4b of the injection plate 3, the fuel is atomized well, and the assist air is introduced in such a way that the two fuel sprays are reliably separated. As a result, a uniform fuel spray is formed.

Note that the fuel particle size of 300 μm is atomized to about 20 to 30 μm by the ejected air when the suction negative pressure is 500 mm) Ig.

As a result, a highly atomized homogeneous air-fuel mixture flows into the combustion chamber from the intake valve 18, and stable and good combustion can be achieved.

The diameter and number of the main air nozzles 8a, 8b and the auxiliary air nozzles 9a, 9b are set appropriately according to the flow rate of the assist air, and the torsion angle φ of the auxiliary air nozzles 9m, 9b also corresponds to the flow rate. and set it properly.

Figures 4(A) and 4(B) show other embodiments of the main air nozzles 8m and 8b, respectively.The main air nozzles are arranged symmetrically so that each pair has a predetermined helix angle. Alternatively, the two main air nozzles 8m and 8b are arranged perpendicular to the fuel spray.

There are no sub-air nozzles 9a and 9b in either case, but the main air nozzle 8
Even with only a and 8b, the minimum required fuel atomization performance is ensured.

(Effects of the Invention) As described above, according to the present invention, high-speed assist air is ejected to intersect at least two parts of the fuel spray, thereby preventing the fuel sprays from intersecting with each other. At the same time, the atomization and atomization of the fuel can be improved, and even air-fuel mixture can be supplied evenly to a plurality of intake valves, thereby improving combustion.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a fuel injector showing an embodiment of the present invention, Fig. 2 is a sectional view taken along line A-A, Fig. 3 is an overall sectional view of the intake system, and Fig. 4 (A) ( B) is an explanatory diagram of an air jet port showing other embodiments. 1... Injector body, 2... Fuel injection nozzle,
3... Injection plate, 4a, 4b... Fuel nozzle, 5
...Adapter, 6...Air gear rally, 8m, 8b.
...Main air nozzle, 9a, 9b...Sub air nozzle. Patent applicant Nissan Motor Co., Ltd. Figure 1

Claims (1)

[Claims] 1. In a fuel injection device for an internal combustion engine that injects high-velocity air into fuel immediately after injection from a nozzle, a nozzle that injects fuel in at least two different directions and air that jets air between them to separate each fuel spray. A fuel injection device for an internal combustion engine, comprising: a nozzle;