JPH0424144Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is an electronically controlled fuel injection system for internal combustion engines (hereinafter also referred to as engines) of automobiles, etc.
The present invention relates to electromagnetic fuel injectors that inject fuel upstream of a throttle valve, and more particularly to an atomization mechanism for atomized fuel flow.

BACKGROUND ART In an electronically controlled fuel injection system, a system in which fuel is injected upstream of a branch gathering part of an intake manifold can reduce the number of electromagnetic fuel injectors, so it is possible to reduce the number of electromagnetic fuel injectors. It has the advantage of reducing manufacturing costs compared to . Among the devices that adopt this type of system, the
What was disclosed in Publication No. 66165 is a throttle
The electromagnetic fuel injector upstream of the valve is provided with multiple swirl sections to atomize the fuel into multiple atomized fuel streams.

Problems that the invention aims to solve However, this electromagnetic fuel injector has a swirling part (swherer) on the outside (engine side) of the fuel opening/closing part.
Since there are multiple injection ports and an injection port is placed on the outside to measure the fuel, the flow of fuel downstream from the opening/closing part becomes irregular. As a result, when the fuel temperature rises, vapor is more likely to be generated downstream of the opening/closing part, and there is a difference in the amount of fuel measured at room temperature and at high temperature, resulting in the problem that even with the same valve opening time, the amount of fuel injected is smaller at high temperature. was appearing.

In addition, when multiple swirling flows are injected within the limited space of the throttle body, a considerable amount of fuel adheres to the inner wall of the throttle body passage, making it difficult to distribute the fuel to each cylinder and respond to transient conditions. There was a problem with significant losses.

In addition, in the case of electromagnetic fuel injectors that generally have a spherical valve, the volume (dead space) from the valve opening/closing part to the tip of the fuel injection port is large, so when the valve opening time becomes shorter, the fuel flow rate slows down and the spray angle decreases. is considerably narrower than when fully open. In addition, the fuel at the tip of the fuel injection port becomes difficult to run out, and fuel adheres to the fuel outlet.
The problem was that large droplets fell into the engine, causing spikes in the air-fuel ratio and CO, as shown in Figure 8.

In addition, if there are burrs or burrs on the fuel outlet,
There is a problem in that fuel droplets fly around the outer periphery of the injected fuel flow, and fuel tends to adhere to the fuel outlet, forming large droplets that fall into the engine, impairing operating performance (including emissions). Ta. For this reason, if an attempt is made to remove burrs, burrs, etc. from the fuel outlet portion by machining, there is a risk that a step will be formed or the fuel outlet portion will be machined into a tapered shape. Depending on the shape of the fuel outlet, the sprayed fuel flow may be deflected or the fuel flow rate may change, impairing distribution properties and transient reactivity, and making it impossible to measure with high precision as an electromagnetic fuel injector.

This design uses a structure in which fuel flows in the order of the valve opening/closing section, metering section, and atomization mechanism, which prevents the generation of vapor and improves the accuracy of the fuel injection amount, and also prevents the sprayed fuel flow from adhering to the inner wall of the passage. The atomization mechanism is equipped with an adapter that controls the atomization so as to prevent the fuel from hitting the throttle valve shaft. The purpose of the present invention is to provide an electromagnetic fuel injector that has good characteristics, distribution performance, and transient response, and has a stable air-fuel ratio.

Means and Effects for Solving Problems In this invention, a cylindrical protective stand attached to the fuel injection port of an electromagnetic fuel injector is installed at the center of the intake cylinder at the tip of the cylindrical protector, parallel to the throttle valve shaft.
Attach an adapter in which the fuel guide surface of a polygonal rod-shaped fuel guide member with a triangular cross section is positioned in a diverging shape from upstream to downstream, so that the direction in which the fuel injected from the fuel injection port of the electromagnetic fuel injector is strong is attached. The fuel is effectively and quickly supplied to a predetermined gap of the throttle valve by contacting the fuel guide member while maintaining its properties and speed, and atomization is further promoted, and the protective base is molded. A parting line of the type formed on the inner peripheral surface of the protective stand is formed to avoid the fuel outlet of the lower end surface of the protective stand and the fuel guide surface, so that the fuel adhering to the inner peripheral surface of the protective stand is prevented from entering the protective stand. This prevents the particles from accumulating on the lower edge of the circumferential surface and falling off.

As a result, the present invention can quickly supply sufficiently atomized fuel to the internal combustion engine through the gap between the throttle valve and the fuel supply cylinder even when the engine is suddenly accelerated from a light load state such as idling. Improves distribution and response characteristics, and stabilizes fuel supply and evenly distributes fuel to each cylinder even if intake air is disturbed for some reason during steady operation with the throttle valve half open. In addition, it is possible to prevent changes in engine characteristics caused by dripping of fuel, which is likely to be affected during light load operation with less supplied fuel, and to stabilize engine operating characteristics along with combustion.

Embodiments This invention will be described below based on drawings showing embodiments. Fig. 2 is a partial cross-sectional view of the intake cylinder 1 of an engine (not shown), in which 2 is the throttle valve installed upstream of the branch assembly, 3 is the throttle valve shaft, and 11 is the throttle valve installed upstream of the throttle valve 2. It is an electromagnetic fuel injector. 1st
The figure is a partially cutaway detailed view of the electromagnetic fuel injector 11. 12 is a valve seat, and there is an injection port 13 at the tip.
The valve opening/closing part 14 behind the injection port 13 is opened and closed by a valve element 16 of an opening/closing valve 15 that moves forward and backward. The figure shows a closed state in which the valve element 16 is in contact with the valve opening/closing part 14. The rear part of the valve seat 12 is fixed to an injector case 17, and an electromagnetic coil 18 is attached to the injector case 17. Valve seat 1
2 and the injector case 17 are O-rings 19, 2
It is fixed to the coupling member 21 via 0. 22
23 is a fuel chamber, and 24 is a filter. A recess 25 is formed outside the injection port 13 by an extension of the valve seat 12, and an adapter 26 is fitted into the recess 25. The adapter 26 is manufactured by molding such as resin molding or cold forging, and as shown in FIG. Consisting of Fuel guide member 28
is arranged across the outlet side opening of the protection stand 27, with one vertex of the triangle facing toward the injection port 13. The adapter 26 is connected to the fuel guide member 2
8 is fitted into the recess 25 so that each ridgeline is parallel to the axis of the throttle valve shaft 3 on the downstream side. The slope of the fuel guide member 28 is composed of a fuel guide surface 28a and a fuel relief surface 28b located below the fuel guide surface 28a and having a different slope. The relationship between the apex angle θ1 of both guide surfaces 28a and the apex angle θ2 of both relief surfaces 28b is such that θ ₁ >θ ₂ ≧0. The molded parting 27a of the protection stand 27 is located above the fuel outlet portion 27b so as not to be affected by burrs, burrs, etc. For the fuel guiding member 28, a fuel relief surface 28 as described above is provided.
b, and a parting 28c is positioned at the lower edge of the parting 28c to prevent burrs, burrs, etc. from occurring in the substantial fuel outlet portion 28d.

Electromagnetic fuel injector 11 configured as described above
is attached to the intake manifold 1 via a coupling member 21. When a valve opening signal is input to the electromagnetic coil 18, the opening/closing valve 15 is pulled up and the valve element 16 opens the valve opening/closing portion 14. The fuel is precisely measured from the fuel chamber 23 through the valve opening/closing part 14 and the injection port 13, becomes a sprayed fuel flow, and hits the adapter 26.
The sprayed fuel flow F is further atomized, separated by the fuel guide surface 28a, and has a certain angle (Fig. 2).
It gushed out. In FIG. 2, the atomized fuel flow F ejected from the electromagnetic fuel injector 11 is injected into the upper and lower surfaces of the throttle valve 2 and does not hit the throttle valve shaft 3. Also, when the engine is running, the intake passage inner wall 1a
There is a high-speed air flow between the throttle valve 2 and the throttle valve 2, and the line of intersection between the spread angle of the sprayed fuel flow F and the intake passage inner wall 1a is the throttle valve 2 when fully closed.
(approximately 1 in this example)
cm) or less, the atomized fuel flow F
is merged with the air flow and does not adhere to the inner wall 1a of the intake passage. FIG. 6 is a projection of the atomized fuel stream F diverted by the adapter 26 onto the plane of the throttle valve 2.

The fuel injected from the electromagnetic fuel injector 11 according to this invention is metered by the valve opening/closing part 14 and the injection port 13 and then hits the adapter 26, so that the fuel flows regularly until the metering is completed. Therefore, even if the fuel temperature rises, abnormal vapor does not occur, and stable metering is possible even at high temperatures. adapter 26
The spray angle of the fuel that hits the fuel guide surface 28a is determined to be approximately constant depending on the angle of the fuel guide surface 28a, and the sprayed fuel flow is divided into atomized particles and then ejected. At this time, the fuel outlets 27b and 28d are formed by the molded parting 27.
Since it is located at a position that is not affected by the elements a and 28c, the flow of the sprayed fuel is not obstructed by burrs, burrs, or the like. Therefore, the air-fuel ratio and CO spikes caused by fuel dripping as shown in FIG. 8 are eliminated, and the idle speed and emission become very stable and good.

Figures 4 and 5 show alternative embodiments 29, 32 of the adapter. protection stands 30, 33, respectively;
Fuel guide members 31, 34, fuel guide surfaces 31a, 3
4a, fuel relief surfaces 31b, 34b, protection stand partings 30a, 33a, fuel outlet section 30
b, 33b, fuel guide member parting 31
c, 34c, and similarly have fuel outlet portions 31d, 34d.

Figure 7 shows the throttle opening and air-fuel ratio for three cases: a conventional atomization mechanism A with a pintle attached to the tip of the on-off valve, an atomization mechanism B with an adapter of this invention, and a case C without a special atomization mechanism. This shows the relationship between fluctuations. The effects of the atomization mechanisms A and B are clear from the graph, and it can be seen that the adapter according to this invention has a simple structure and exhibits the same effect as the conventional pintle, which has a complicated structure.

Although the electromagnetic fuel injector according to this invention is intended to improve the atomization mechanism for single-point fuel injection, similar effects can be obtained when applied to multi-point fuel injection.

Effects of the invention As explained above, this invention
In an electromagnetic fuel injector installed upstream of the valve, an adapter with a substantially uniform cross section that divides the atomized fuel flow is connected to the throttle valve at the tip of the fuel injection port.
The parting is placed almost parallel to the valve shaft, and the adapter is molded with a parting that avoids the fuel outlet, so that the fuel hits the after-adapter after being precisely metered. , the fuel injection amount is always stable and has the effect of maintaining a highly accurate flow rate.

In addition, since the atomized fuel flow does not hit the inner wall of the intake passage or the throttle valve shaft, and no fuel drips at the fuel outlet of the adapter, good atomization characteristics, distribution performance, and response are always achieved. This has the effect of significantly improving driving performance and fuel efficiency over the entire driving range.

Conventionally, the atomization mechanism of electromagnetic fuel injectors is complicated.
In addition, high processing accuracy was required, but the adapter invented by this invention has a simple structure, so molding processing (resin molding, cold forging, die casting, etc.) is possible, there is little variation, and manufacturing costs are reduced. It has the effect of

[Brief explanation of the drawing]

The drawings show an embodiment of this invention; Fig. 1 is a partially cutaway detailed view of the embodiment, Fig. 2 is a partial vertical sectional view of an intake cylinder 1 equipped with an electromagnetic fuel injector according to this invention, and Fig. 3a. , b to 5 a and b are plan views and longitudinal cross-sectional views of essential parts of various embodiments, respectively.
FIG. 6 is a projection of the atomized fuel flow onto the throttle valve according to the embodiment shown in FIG. 3, FIG. 7 is an air-fuel ratio characteristic diagram for the conventional atomization mechanism and the atomization mechanism of this invention, and the case without the atomization mechanism. is an explanatory diagram of the air-fuel ratio and the occurrence of CO spikes due to fuel dripping. 1...Intake cylinder, 3...Throttle valve shaft, 11...Electromagnetic fuel injector, 13...Fuel injection port, 15...Opening/closing valve, 26, 29, 32...
Adapter, 27a, 28c, 30a, 31c, 3
3a, 34c...Parting.

Claims (1)

[Scope of utility model registration request] A fuel guide surface of a polygonal rod-shaped fuel guide member having a triangular cross section is placed parallel to the throttle valve shaft at the center of the intake cylinder at the tip of the cylindrical protection stand attached to the fuel injection port of the electromagnetic fuel injector. Attach an adapter that widens from upstream to downstream so that the fuel injected from the fuel injection port of the electromagnetic fuel injector hits the fuel guide member while maintaining strong directionality and velocity, creating a mist. In order to effectively and promptly supply the throttle valve to a predetermined gap in the throttle valve in a state in which the oxidation is further promoted, and to form a mold part on the inner circumferential surface of the protector when the protector is molded, A running line is formed to avoid the fuel outlet of the lower end surface of the protection stand and the fuel guide surface to prevent fuel adhering to the inner circumference of the protection stand from accumulating on the lower edge of the inner circumference of the protection stand and falling off. An electromagnetic fuel injector featuring