JP2514944Y2 - Fuel injector - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a fuel injection device of a type generally called a single point injector (SPI),
Particularly, the present invention relates to a fuel injection device of a type in which a throttle body on which an injector is mounted is attached to an intake manifold from a lateral direction.

<Prior Art> The present applicant has already proposed a fuel injection device of this type having the structure shown in FIG. In FIG. 5, the throttle body 120 includes an upper body 122 having an intake passage 124 and a lower body 12 having a throttle bore passage 128.
It is composed by connecting 6 and each other. And
An injector 140 is mounted on the upper body 122, and a throttle valve 150 is incorporated in a throttle bore passage 128 of the lower body 126.

The fuel is set so as to be injected from the injector 140 toward the throttle shaft 152 of the throttle valve 150, thereby atomizing the fuel.

<Problems to be Solved by the Invention> In the above configuration, when the throttle valve 150 is in the low opening range as shown in FIG. 6, the fuel injected from the injector 140 hits the throttle shaft 152 and is far from the valve 150. The phenomenon of jumping back to a distant position occurs. This bounced fuel will flow into the intake manifold along the lower surface in the throttle bore passage 128.
This tends to cause the air-fuel ratio to fluctuate, causing deterioration of the transient characteristics.

<Means for Solving the Problems> In order to solve the above problems, the fuel injection device of the present invention is configured as follows.

That is, the throttle body to which the injector is attached is installed laterally with respect to the intake manifold, and the throttle valve is installed in the throttle bore passage leading to this intake manifold. A fuel injection device of the type that injects fuel toward a shaft, wherein a through hole communicating from a side receiving fuel injected by the injector to an opposite side thereof is provided in the throttle shaft upstream when the throttle valve is closed. It is formed individually on each of the side and the downstream side.

<Operation> According to this configuration, the fuel injected from the injector is divided into one that collides with the throttle shaft of the throttle valve and rebounds, and one that passes through the through hole. When the opening of the throttle valve is maintained in a state where the valve surface and the fuel injection direction from the injector are in parallel, or when the throttle valve temporarily enters this state such as during acceleration, In any case, most of the injected fuel passes through the through hole, rides on the fast flow of intake air, and is supplied to the intake manifold side in the shortest distance. As a result, for example, a fuel supply delay at the time of acceleration is eliminated, and fluctuations in the air-fuel ratio are suppressed.

<Embodiment> Next, an embodiment of the present invention will be described with reference to FIGS.

First, the second part of the engine intake system that uses a single-point injector type fuel injection system.
In the figure, the throttle body 20 is mounted on the vehicle,
The engine 10 is attached to an intake manifold 12 from a lateral direction. And this throttle body
An injector 40 is mounted on 20. It is well known that the fuel injected from the injector 40 and the air sucked from the air cleaner 14 are mixed inside the throttle body 20 and supplied to each cylinder of the engine 10.

As is apparent from FIG. 1 showing the throttle body 20 in an enlarged cross-section, the throttle body 20 is arranged on the air cleaner 14 side and has an upper body 22 having an intake passage 24 therein, and the intake manifold. Directly assembled to 12 and has a throttle bore passage inside
Is divided into a lower body 26 having 28. The upper body 22 and the lower body 26 are connected to each other by a bolt or the like via a gasket 30 for maintaining airtightness therebetween.

When the throttle body 20 is assembled to the intake manifold 12, the intake passage of the upper body 22
24 is kept almost horizontal. On the other hand, the throttle bore passage of the lower body 26 has an inclination angle that gradually decreases toward the intake manifold 12.

By the way, in the throttle bore passage 28 of the lower body 26,
The throttle valve 50 is mounted so as to be rotated around the axis of the throttle shaft 52. That is, the throttle valve 50 is rotated in the counterclockwise direction in the drawing with the throttle shaft 52 as the axis from the fully closed position shown by the phantom line in FIG. 1 in conjunction with the depression operation of the accelerator pedal (not shown). It is.

On the other hand, the injector 40 is attached to the upper body 22, and the throttle body 20 is attached to the injector 40.
The fuel tube 42 is connected to the end portion located outside of the engine by a connecting pipe 44 and a connecting plug 46. Also,
The end of the injector 40 on the nozzle side inside the throttle body 20 is set so as to inject fuel toward the throttle shaft 52 of the throttle valve 50.

3 and 3 which are enlarged views of the main part of FIG.
Fig. 4 seen from the direction of arrow IV in the figure, throttle shaft 52
As is apparent from FIG. 5 which is a perspective view of a part of the throttle valve, the throttle valve 52 is attached to the throttle shaft 52.
A through hole 54 having a diameter larger than the width of the slit 56 and penetrating in the radial direction of the throttle shaft 52 is formed at a substantially intermediate portion of the slit 56 to which the is attached (see mainly FIG. 5).

Therefore, when the throttle valve 50 is attached to the slit 56 of the throttle shaft 52, the through hole 54 is formed on the upstream side and the downstream side of the throttle valve 50.
The opening is located so as to communicate from the side receiving the fuel injected by the injector 40 to the opposite side. As a result, the fuel injected from the injector 40 collides with the surface of the throttle shaft 52 and bounces back, and
It is divided into those that pass through and flow down along the valve surface.

The injector 40 is assembled to the upper body 22 in a compact design for mounting on a vehicle, and the resistance of the air flowing through the intake passage 24 of the upper body 22 is not increased.

Further, an idling control air passage 32 is generally formed in the lower body 26. The flow rate of the air flowing through the idling control air passage 32 is adjusted by an adjusting screw 34. The idling control air passage 32 is connected to the injector 40
It is formed at an optimum position to avoid the intrusion of the fuel injected from the fuel tank. In other words, the opening position on the inlet side of the idling control air passage 32 is close to the outer peripheral portion of the injector 40, and the opening on the outlet side is the throttle bore passage.
It is always set to a position on the downstream side of the throttle valve 50 within 28.

In the fuel injection device configured as described above, it is assumed that the throttle valve 50 is in the low opening range (when the vehicle is running at low speed or idling) as shown in FIGS. 1 and 3, for example. Therefore, the fuel from the injector 40 is supplied to the throttle valve 50 as described above.
When the fuel is injected toward the throttle shaft 52, the injected fuel collides with the outer peripheral surface of the throttle shaft 52 and bounces back, and passes through the through hole 54 located on the upstream side of the throttle valve 50 to It is divided into those that run down along. The fuel atomized by colliding with the throttle shaft 52 is properly mixed with the intake air flowing through the throttle bore passage 28. On the other hand, the fuel that has flowed down through the through hole 54 is also caused by the rapid flow of intake air.
Engine from intake manifold 12 at the shortest distance
It is supplied to the cylinder of the intake stroke at 10.

Further, although not shown, when the throttle valve 50 is in the high opening range, the fuel injected from the injector 40 collides with the throttle shaft 52 and is widely scattered in the throttle bore passage 28, Throttle valve
It passes through the through hole 54 located on the downstream side of 50 and is divided into those flowing along the valve surface. Therefore, when the throttle valve 50 is in the high opening range, the fuel easily rides on the intake air flowing through the throttle bore passage 28, and this air and the fuel are appropriately mixed and supplied from the intake manifold 12 to the cylinder in the intake stroke. .

As a result, the fluctuation of the air-fuel ratio is small and the transient characteristics are good in both the low opening range and the high opening range of the throttle valve 50.

When the throttle valve 50 is in the low opening range as shown in FIG. 1, the hot water passage 60 is formed on the lower inner surface of the throttle bore passage 28 upstream of the throttle valve 50, that is, on the lower wall of the lower body 26. Good. In the hot water passage 60, for example, a part of engine cooling water is circulated.

According to this configuration, mainly the throttle valve 50
Is in the low opening range, among the fuel injected from the injector 40, it collides with the throttle shaft 52 and bounces back,
The fuel attached to the inner surface of the lower portion of the throttle bore passage 28 is heated by the hot water flowing in the hot water passage 60, and the atomization thereof is promoted. As a result, the idling state and the like when the throttle valve 50 is in the low opening range are stabilized, and the transient characteristics are improved.

As described above, according to this embodiment, for example, in the low opening range of the throttle valve, fuel injected from the injector collides with the throttle shaft of the throttle valve and bounces off, and passes through the through hole formed in the throttle shaft. The fuel bounce distance becomes smaller, and the fuel that has passed through the through hole flows down along the valve face of the throttle valve and rides on the fast flow of intake air and is supplied to the intake manifold at the shortest distance. Becomes As a result, the fuel supply delay in the low opening range of the throttle valve is prevented, the fluctuation of the air-fuel ratio is suppressed, and the transient characteristics are improved.

<Effect of the Invention> Since the present invention is configured to allow the injected fuel to pass through through holes formed in the throttle shaft on each of the upstream side and the downstream side when the throttle valve is closed, When the direction of fuel injection from the injector is parallel to the valve surface of the throttle valve, most of the injected fuel passes through the through holes and enters the fast flow of intake air, and is supplied to the intake manifold side in the shortest distance. As a result, the fuel supply delay at the time of acceleration or the like is eliminated and the fluctuation of the air-fuel ratio is suppressed.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention. FIG. 1 is a sectional view of a single-point injector type fuel injection device, and FIG. 2 is an intake system adopting the fuel injection device of FIG. FIG. 3 is a configuration diagram schematically showing the system, FIG. 3 is a sectional view showing the main part of FIG. 1 in a further enlarged manner, FIG. 4 is a plan view seen from the direction of arrow IV in FIG. 3, and FIG. FIG. 3 is an external perspective view showing a part of a throttle shaft. FIG. 6 is a longitudinal sectional view showing a conventional fuel injection device in correspondence with FIG. 1. 12 …… Intake manifold 20 …… Throttle body 28 …… Throttle bore passage 40 …… Injector 50 …… Throttle valve 52 …… Throttle shaft 54 …… Through hole

Claims (1)

(57) [Scope of utility model registration request] 1. A throttle body, to which an injector is attached, is laterally assembled with respect to an intake manifold, and a throttle valve is incorporated in a throttle bore passage communicating with the intake manifold. A fuel injection device of a type that injects fuel toward a throttle shaft of a valve, wherein the throttle valve has a through hole communicating from a side receiving fuel injected by the injector to an opposite side thereof. The fuel injection device is individually formed on each of the upstream side and the downstream side.