JPH01300060A - Structure of throttle body - Google Patents

Abstract

PURPOSE:To reduce intake resistance and prevent liquid fuel from remaining by arranging an injector to the lower side of intake passage, and inclining the lower face of the passage such that the downstream side is set below in the lower side of nozzle part of injector. CONSTITUTION:A throttle body 10 of side flow type is composed of an upstream side injector mounting part 7 and downstream side bore part 8, which are con nected with bolt 1 through insulator 9. In this case, in a mounting part 7, an intake passage 2a therein is horizontal at the upstream side, and after it is bent in the slantly lower direction by only a specified angle alpha, it is formed so as to reach a downstream end 16. A retaining hole 12 is formed at a lower wall 17 of a mounting part 7, and an injector 1 is fitted in this hole 12. The axis L of injector 1 is inclined downwards at only a specified angle beta, and the lower face 13 of the passage 2a is similarly inclined.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of a throttle body disposed in the intake system of an engine, and specifically relates to a side-flow type throttle body of a fuel injection engine equipped with an injector upstream of a throttle valve. This relates to the structure of the throttle body.

(Prior Art) There are two types of throttle bodies: a down-flow type in which intake air flows downward in the throttle body, and a side-flow type in which intake air flows approximately horizontally in the throttle body.

The latter has the advantage that the installation space in the vertical direction can be narrowed. As disclosed in Japanese Unexamined Patent Publication No. 62-60977, in the conventional side flow type engine, an injector is arranged approximately in the cross section of an intake passage formed in a throttle body.

(Problem to be Solved by the Invention) However, according to the above conventional example, since the injector is arranged in the center of the intake passage, there is a problem that it becomes an obstacle to the flow of intake air and increases intake resistance. There is a problem in that the structure for supporting the injector in the center of the intake passage becomes complicated.

Therefore, the inventor of the present invention came up with the idea of arranging the injector at a position where it does not interfere with the flow of intake air, that is, on the side of the intake passage. Moreover, in view of the relationship between the opening direction of the commonly used throttle valve and mixing, we have arrived at the idea that it is optimal to arrange the injector at the lower side of the intake passage. However, in this case, the nozzle part of the injector and the lower surface of the intake passage are in a close positional relationship, so
There is a risk that liquid fuel dripping from the nozzle portion may remain on the lower surface of the intake passage. For this reason, problems arise in that it becomes difficult to obtain an appropriate air-fuel ratio and that responsiveness to accelerator operation becomes poor.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a side flow type throttle body for a fuel injection engine equipped with an injector upstream of a throttle valve. The injector is disposed on the lower side, and the lower surface of the intake passage is inclined so that the downstream side is downward below the nozzle of the injector.

(Function) According to the present invention, since the injector is provided at the lower side of the intake passage, it does not obstruct the flow of intake air, and intake resistance can be reduced.

Further, according to the present invention, the lower surface of the intake passage below the nozzle of the injector is inclined so that the downstream side is downward, so that the liquid fuel dripping from the nozzle part is guided downstream and flows into the part. As a result of no accumulation of fuel and a proper amount of fuel being continuously delivered to the intake manifold, the air-fuel ratio can be maintained appropriately and responsiveness to accelerator operation can be improved.

(Example) An embodiment of the present invention will be described based on FIGS. 1 and 2.

The illustrated side flow type throttle body 10 consists of an injector mounting portion 7 on the upstream side and a bore portion 8 on the downstream side, both of which are connected with bolts 11 via an insulator 9.

The injector mounting portion 7 is formed so that the intake passage 2a therein becomes horizontal on the upstream end 15 side, and then bends obliquely downward at a predetermined angle α (45° in the case shown) and reaches the downstream end 16. has been done.

An injector holding hole 12 is formed in the lower wall 17 of the injector mounting portion 7, and the injector 1 is mounted in this holding hole 12. The nozzle portion 1a of the injector 1 is configured to protrude a certain amount into the intake passage 2a, so that the nozzle portion 1a faces a lower portion of the intake air flowing through the intake passage 2a. The axis of the injector 1 is tilted downward at a predetermined angle β (10° in the illustrated case), and the lower surface 13 of the intake passage 2a is also tilted downward at a predetermined angle β.
It's leaning.

The bore portion 8 has an intake passage 2b communicating with the intake passage 2a of the injector mounting portion 7, and is provided with a throttle valve 3 supported by a pivot 4 within the intake passage 2b. This throttle valve 3 rotates in the direction shown by the arrow in FIG.
, the upper part serves as an upstream opening portion 3b.

The axis of the intake passage 2b of the bore portion 8 is inclined at a predetermined angle T (20° in the illustrated case) so that the downstream side is lower. The lower surface of the intake passage 2b is inclined at a predetermined angle β so as to be continuous with the lower surface 13 of the intake passage 2b of the bore portion 8 on the upstream side 18a, and on the downstream side 18b,
It is inclined at a predetermined angle T.

The fuel injection axis direction (approximately 0° downwardly inclined) P of the injector 1 is set to intersect at a proper position of the downstream opening portion 3a of the throttle valve 3,
The fuel injected from the injector 1 mainly hits the upstream side surface F of the downstream opening section 3a.

The lower wall 19 of the bore portion 8 is provided with a water jacket 20 at a position below the throttle valve 3, so that hot water (engine cooling water) from the engine circulates in the direction of the arrow to heat the lower wall 19. I have to. Note that an intake manifold (not shown) is connected to the downstream end 21 of the bore portion 8.

Thus, the intake passage 2 (the passage 2a of the injector mounting part 7
, the passage 2b of the bore portion 8. ), the fuel injected from the injector l is mixed with the intake air. The fuel is injected toward the upstream side surface F of the downstream opening portion 3a of the throttle valve 3, where it is reflected downward. This relationship is maintained regardless of the opening position of the throttle valve 3, and the flow of fuel is prevented from changing suddenly at the opening position of the throttle valve 3.

The fuel reflected by the throttle valve 3 adheres to the lower downstream side 18b of the intake passage 2b in a liquefied state, but is guided by the slope of the lower downstream side 18b to the intake manifold and is prevented from accumulating in this part. It will be done. at the same time,
It is heated by the hot water from the water jacket 20 and evaporation is promoted.

Further, since the nozzle portion 1a of the injector 1 faces downward, it is possible to reduce the accumulation of liquid fuel at the tip. Further, since the nozzle portion 1a is located close to the lower surface 13 of the intake passage of the injector mounting portion 7, the nozzle portion 1a
There is a risk that the liquid fuel that has dripped from the air will accumulate on the lower surface 13 of the intake passage, but in this embodiment, the lower surface 13 of the intake passage is sloped, so that the liquid fuel is transferred to the lower surface 13 of the intake passage and the bore portion 8 side. intake passage lower surfaces 18a, 18b
It can be guided through the top and guided to the intake manifold side.

Note that, of course, the angles α, β, and T are not limited to those shown in the drawings.

(Effects of the Invention) According to the present invention, it is possible to provide a side flow type throttle body that can reduce intake resistance, can maintain an appropriate air-fuel ratio, and has good responsiveness to accelerator operation. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the main part thereof. ■−・・−１−−−−・−・−Injector 1a−・−
−−−−−−−−−−Nozzle part 2−・−・−・・−Intake passage

Claims (1)

[Claims] (1) In a side flow type throttle body for a fuel injection engine that has an injector upstream of the throttle valve, the injector is placed below the intake passage formed in the throttle body, and the intake air is placed below the nozzle of the injector. A throttle body structure characterized in that the lower surface of the passage is inclined so that the downstream side is downward.