JPH0210292Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This invention relates to an improvement of a fuel injection carburetor for an internal combustion engine.

[Prior art]

In recent years, as one of the fuel injection devices used in automobile engines controlled by electronic control units consisting of microcomputers, one fuel injection valve is disposed within the intake passage in the throttle body portion on the upstream side of the intake manifold. There is a fuel injection carburetor called a so-called single point injector that injects fuel upstream of a throttle valve provided in the throttle body. In the case of an engine using such a fuel injection carburetor, in order to stabilize engine idling, the outlet of the bypass passage that bypasses the throttle valve and guides air from upstream to downstream is located upstream of the intake manifold. Since it must be provided on the side and downstream of the throttle valve, it must necessarily be provided at a downstream position close to the throttle valve within the intake passage of the throttle body. However, the fuel injected from the fuel injection valve of the fuel injection carburetor is not completely atomized under all engine operating conditions, and some of it adheres to the inner wall of the intake passage of the throttle body and becomes liquid. The fuel flows down with the intake air flow and reaches the outlet of the bypass passage located adjacent to the downstream side of the throttle valve, or the fuel injected from the fuel injection valve directly adheres to the outlet and the fuel flows from there into the bypass passage. It may enter the passageway. In this way, if liquid fuel adheres to the outlet of the bypass passage or if the liquid fuel enters the bypass passage, the pressure state near the outlet of the bypass passage becomes unstable, and as a result, the air passing through the bypass passage becomes unstable. There was a problem in that the amount of fuel became unstable, and furthermore, the liquid fuel that had entered the bypass passage flowed out into the throttle bore, making the idle operating state of the engine unstable. Furthermore, the fuel spray angle θ of the fuel injection valve in the above-mentioned fuel injection carburetor is generally considered to be preferably 60° to 90°, but the fuel sprayed from the fuel injection valve is Depending on the situation, the fuel may flow down over the upstream opening tip of the throttle valve, or may flow exclusively from the downstream opening tip and move from side to side within the throttle bore, causing fuel to flow into each cylinder of a multi-cylinder engine. Dispersion may occur in the amount dispensed. In particular, when the intake manifold is cold or when there are differences in the shape of the intake manifold, the variations are significant and have a negative effect on engine output, and the response of engine output to changes in throttle valve opening, that is, transient response, is insufficient. There was a problem.

[Purpose of invention]

This idea was made in view of the above problem, and even if the outlet of the bypass passage is provided adjacent to the downstream side of the throttle valve, fuel may adhere to the outlet, or the bypass passage may not flow from the outlet. Prevents fuel from entering the passage, thereby
It is an object of the present invention to provide a fuel injection carburetor capable of stabilizing the idle operating state of an engine. This invention also prevents the fuel sprayed from the fuel injection valve from moving left and right within the throttle bore, reducing the variation in the amount of fuel distributed to each cylinder of a multi-cylinder engine, and thereby improving the engine performance. It is an object of the present invention to provide a fuel injection carburetor capable of stabilizing output and improving engine output response, that is, transient response to changes in throttle valve opening.

[Structure of the idea]

This invention includes a fuel injection valve disposed on the upstream side of a throttle valve facing the throttle valve, and an inlet and an outlet opening in the throttle bore at positions upstream and downstream of the fuel injection valve, bypassing the throttle valve. In a fuel injection carburetor for an internal combustion engine having an idle bypass passage, in a range of a fuel spray angle θ of the fuel injection valve,
One limit of the position where the sprayed fuel reaches the throttle valve surface is set at the upstream opening tip of the throttle valve in the fully open state, and the other limit is set at the downstream end of the throttle valve in the fully closed state. The above object is achieved by arranging the fuel injection valve at each opening tip, and arranging the outlet of the bypass passage on the inner wall of the throttle bore on the opening tip side in the upstream direction of the throttle valve. It is something.

[Effect of invention]

In this device, most of the fuel injected from the fuel injection valve flows down along the inner wall of the throttle bore on the side opposite to the outlet of the bypass passage, and the injected fuel or the fuel that adheres to the inner wall of the throttle bore and becomes liquid flows to the outlet. will not stick.

【Example】

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, this embodiment includes a fuel injection valve 14 disposed on the upstream side of the throttle valve 12 facing the throttle valve 12, and a fuel injection valve 14 that bypasses the throttle valve 12. In a fuel injection carburetor 10 for an internal combustion engine having an idle bypass passage 18 having an inlet 18A and an outlet 18B opened to the throttle bore 16 at upstream and downstream positions, the range of the fuel spray angle θ of the fuel injection valve 14 is One limit of the position where the sprayed fuel reaches the surface of the throttle valve 12 is the upstream opening tip 12B of the throttle valve 12 in the fully open state, and the other limit is the downstream position of the throttle valve 12 in the fully closed state. The fuel injection valve 14 is arranged so as to have a direction opening tip 12A, and the outlet 18 of the bypass passage 18
B is arranged on the inner wall of the throttle bore 16 on the side of the opening end 12B of the throttle valve 12 in the upstream direction. That is, the fuel injection valve 14 has its fuel spray angle center line 15 parallel to the center axis 17 of the throttle bore 16 and closer to the downstream opening tip 12A of the throttle valve 12.
are arranged offset, and the fuel spray angle θ is
The throttle valve 1 in the entire throttle opening range
The range is between the upstream opening tip 12B and the downstream opening tip 12A of No. 2. An outlet 18B of the bypass passage 18 is formed in the throttle bore 16 immediately before being connected to the intake manifold 22, passing through the throttle body 24. Reference numeral 26 in the figure is an idle adjusting screw for adjusting the amount of circulating air by changing the passage area of the bypass passage 18, 28 is a wiring connector for controlling the fuel injection valve 14, 30 is a fuel supply passage, 32 34 is a fuel return passage, and 34 is a fuel injection valve 14.
Support bars 36 each represent a pressure regulator. In this embodiment, the throttle valve 12
The inner diameter of the throttle bore 16 at the periphery is 45mm,
The throttle bore 1 is set such that the distance in the throttle bore axial direction from the swing center axis 13A of the throttle shaft 13 to the tip fuel spray center 14A of the fuel injection valve 14 is 35 mm, and the spray angle center line 15 of the fuel injection valve 14 is
The offset amount X with respect to the center axis 17 of 6 is 5 mm.
In this case, the fuel spray angle θ is 50°. In this embodiment, the spray angle center line 15 of the fuel injection valve 14 is aligned with the center axis 1 of the throttle bore 16.
7, the fuel injection valve 12 is cuff-set on the downstream opening end 12A side of the throttle valve 12, and the fuel spray angle range of the fuel injection valve 14 is such that the position where the sprayed fuel reaches the throttle valve 12 surface is completely In the entire throttle opening range of the throttle valve 12 from the closed state to the fully open state, the throttle valve 12 is always located closer to the downstream opening end 12A than the upstream opening end 12B. Regardless of the opening degree of the throttle valve 12, the fuel sprayed from the fuel injection valve 14 always reaches the downstream opening tip 12A of the throttle valve 12.
There is no or very little flow down along the inner wall of the throttle bore 16 from the upstream rotating tip 12B side, which is the right side in the figure, within the throttle bore 16. Further, since the fuel spray angle θ is made to substantially match the downstream opening tip 12A of the throttle valve 12 in the fully closed state, the range in which the sprayed fuel reaches the upper surface of the throttle valve 12 is limited. , the diameter range is smaller than the inner diameter of the throttle valve 16. Therefore, the atomized fuel flows into the throttle bore 16.
and the throttle shaft 13. The intake flow rate near the intersection of the throttle shaft 13 and the throttle bore 16 is normally slow, so the fuel sprayed here flows through the throttle shaft 13 without being obstructed by the intake air flow near the intersection.
It is conceivable that it may adhere to the inner wall of the throttle bore 16 nearby or pass through the gap between the throttle valve 12 and the throttle bore 16 and reach the inner wall of the throttle bore 16 on the upstream opening tip 12B side or the outlet 18B of the bypass passage 18. According to the above embodiment, all the sprayed fuel flows along the upper surface of the throttle valve 12 toward the downstream opening tip 12A.
Since it flows down from the side, there is little or very little chance that the atomized fuel will adhere to the inner wall of the throttle bore 16 on the upstream opening end 12B side or the outlet 18B. Further, as described above, the fuel spray angle is such that one limit of the position where the sprayed fuel reaches the throttle valve 12 surface substantially coincides with the upstream opening tip 12B of the throttle valve 12 in the fully open state, and the other limit Since the limit is made to substantially coincide with the downstream opening tip 12A of the throttle valve 12 in the fully closed state, the sprayed fuel will not adhere to the inner wall of the throttle bore 16 or the upstream opening tip 12B of the throttle valve 12 will be closed. The maximum spray angle can be obtained within a range where the spray does not flow down beyond the throttle bore 16 and the throttle shaft 13, and therefore fuel atomization is not unnecessarily suppressed. Therefore, in this embodiment, the outlet 18 of the bypass passage 18 located in the throttle bore 16
It is almost impossible for the sprayed fuel to adhere to B or to flow into the bypass passage 18 from here, or it is greatly suppressed, and therefore the pressure in the throttle bore 16 near the outlet 18B of the bypass passage 18 is stabilized. Therefore, the flow rate of air passing through the bypass passage 18 is stabilized, and the fuel that has entered the bypass passage 18 is removed from the throttle valve 1.
It is possible to prevent the idling state of the engine from becoming unstable due to droplets forming in the engine. Further, the sprayed fuel is transferred to the throttle valve 12.
Since it flows down from the downstream opening tip 12A side along the upper surface, it does not move from side to side within the throttle valve 16, and the dispersion in the amount of fuel distributed to each cylinder is reduced, thereby reducing the engine output. This can be stabilized, and the responsiveness of the engine output to changes in the opening degree of the throttle valve 12, that is, the transient responsiveness can be improved. In the above embodiment, the spray angle center line 15 of the fuel injection valve 14, that is, the center axis of the fuel injection valve 14 is offset from the center axis 17 of the throttle bore 16 in parallel to the downstream opening end 12A side of the throttle valve 12. However, the present invention is not limited to this, and the fuel spray angle range of the fuel injection valve 14 is set such that the position where the sprayed fuel reaches the throttle valve 12 surface ranges from a fully closed state to a fully open state. It is sufficient that the throttle valve 12 is always located closer to the downstream opening tip 12A than the upstream opening tip 12B of the throttle valve 12 within the entire throttle opening range of the throttle valve 12. Therefore, the spray center 14A of the fuel injection valve 14 is
It is offset to a position closer to the opening tip 12A in the downstream direction than the throttle bore center axis 17 passing through the swing center axis 13A of the throttle valve 12, and
It is sufficient that the fuel spray angle range of the fuel injection valve 14 is between the upstream tip 12B and the downstream opening tip 12A of the throttle valve 12 over the entire throttle opening range. Therefore, for example, as shown in FIG. 2, the spray angle center line 15 of the fuel injection valve 14 may be inclined with respect to the center axis 17 of the throttle bore 16. In the case of this embodiment, the length of the downstream opening end 12A side portion 34A of the support bar 34 supporting the fuel injection valve 14 in the throttle valve 12 can be made longer than in the case shown in FIG. As a result, the area of the intake passage on the side of the downstream opening tip 12A of the throttle valve 12 is increased, and the intake air flow is strongly guided toward the downstream rotating tip side, and the atomized fuel is directed to the upstream opening tip 12B side. The flow of water can be further suppressed. Further, in the above embodiment, the spray angle center line 15 of the fuel injection valve 14 is inclined clockwise in FIG. 2 with respect to the center axis 17 of the throttle bore 16, but the present invention is not limited to this. Instead, it may be tilted in the opposite direction, that is, counterclockwise, so that the spray range is shown by the two-dot chain line in FIG. In this case, since a part of the fuel injection valve 14 can be disposed so as to protrude outward from the throttle bore 16, the fuel injection valve 14 inside the throttle bore
This has the advantage that the intake air circulation area in the vicinity can be increased. Since the present invention is configured as described above, the fuel can reach the inner wall surface of the throttle bore on the outlet side of the bypass passage provided in the throttle bore downstream of the throttle valve without unnecessarily reducing the fuel spray angle range. It may be possible to prevent or reduce the contact of atomized fuel or deposited liquid fuel with said outlet, thus preventing or reducing the possibility of fuel depositing on said outlet or infiltrating from said outlet into the bypass passage. This has the excellent effect of stabilizing the pressure in the throttle bore near the outlet and preventing destabilization of idle operation due to the flow of infiltrated fuel. In addition, by offsetting the fuel injection valve to the downstream rotating tip side of the throttle valve, the atomized fuel always flows down from the downstream rotating tip side, thereby stabilizing the engine output. This has the excellent effect of improving the response of the engine output to changes in throttle valve opening, that is, the transient response.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a fuel injection carburetor according to the present invention, and FIG. 2 is a cross-sectional view showing a second embodiment of the present invention. 10... Fuel injection carburetor, 12... Throttle valve, 12A... Downstream opening tip, 12B...
... Upstream direction opening tip, 14 ... Fuel injection valve, 14
A... Fuel spray center, 15... Fuel spray angle center line, 16... Throttle bore, 17... Center axis line, 18... Bypass passage, 18A... Inlet, 1
8B...Exit, 24...Throttle body, 26
...Idol Asian Strike Screw.

Claims (1)

[Scope of utility model registration request] A fuel injection valve disposed on the upstream side of the throttle valve and facing the throttle valve, and an idle bypass passage whose inlet and outlet are opened to the throttle bore at upstream and downstream positions, bypassing the throttle valve. In the fuel injection carburetor for an internal combustion engine, one limit of the position where the sprayed fuel reaches the throttle valve surface in the fuel spray angle range of the fuel injector is set to The fuel injector is disposed at the upstream opening tip and the other limit is set at the downstream opening tip of the throttle valve in a fully closed state, and
A fuel injection carburetor for an internal combustion engine, wherein an outlet of the bypass passage is arranged on an inner wall of the throttle bore on the upstream opening side of the throttle valve.