JPS6073051A - Suction device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To make suction air distributable uniformly to each cylinder, by making a center line of a branch pipe from a concentrating part off set from a center line of the concentrating part in the same direction as a direction where a center line of an injector is offset from the center line of a throttle bore. CONSTITUTION:An injector nozzle 18' is set up as being offset, and fuel out of an injector 18 drops down at the right from a center line OT of a throttle bore 12, namely, a position being slipped to the right from a center line OA of a concentrating chamber as in an arrow F. However, a center line OB of a first branch part 26 is offset at a joining end 22A with a concentrating part 22, and this fuel stream being dropped just passes through the center line OB of the first branch 26. With this constitution, fuel results in passing the center of the first branch part 26 and thereby is uniformly distributed to a branch pipe 24, thus it is uniformly distributed to each cylinder.

Description

TECHNICAL FIELD The present invention relates to a technique for improving air-fuel mixture distribution characteristics in an internal combustion engine of the type in which a fuel injector is provided upstream of a throttle valve.

One conventional fuel injector was installed upstream of the throttle valve.
There is a so-called single point injector type fuel injection internal combustion engine. Usually, the centerline of the injector is arranged to match the centerline of the throttle bore. In this case, the position at which fuel falls from the throttle bore to the intake manifold assembly changes depending on the IIJt slope of the throttle valve, which means that the fuel distribution to each cylinder changes depending on the opening degree of the throttle valve. do.

In order to solve this drawback and to stabilize the fall position of the fuel regardless of the extension of the throttle valve, the applicant has proposed to offset the center line of the injector to the side occupied by the lower half of the throttle valve when it is tilted. I have already proposed what I have done. In this case, the falling position of the fuel generally settles at a fixed position 1 of the collecting part of the intake manifold, but this falling position is offset from the center line from the manifold collecting part to the branch pipe of each cylinder. Therefore, distribution equality changes between each cylinder, which becomes a problem.

Object and Structure of the Invention 2 The present invention aims to further improve the improved technology according to the present application in terms of distribution equality. In order to achieve this objective, the center line of the branch pipe from the collecting part is offset from the collecting part centerline in the same direction as the direction in which the center line of the injector is offset from the throttle bore center line.

Embodiment In FIG. 1, lO is a throttle body, which forms a throttle bore 12. In FIG. A throttle valve 14 is disposed within the throttle pore 12 so as to be freely rotatable around a valve shaft 16 . 18 is a fuel injector, and throttle valve 14
The support portion 101 of the throttle body 10 is located upstream of the
can be attached to. The center line of the injector 18 is represented by 02, which is 3 from the center line oT of the throttle bore 12.
There is an offset of 1. The offset direction is the side occupied by the lower side of the throttle valve 14, which is located at an angle. In this case, the fuel spray from the nozzle 18' of the injector 18 is indicated by F, and most of the fuel flow is on the side of the throttle bore where the lower half of the throttle valve is located, that is, on the right side of the figure with respect to the centerline OT of the throttle bore. The falling position of the fuel is concentrated as shown by F with almost no variation.

An intake manifold 20 is located below the throttle body 10. The intake manifold 20 includes a gathering part 22 that is attached to the throttle body, a branch pipe part 24 to each cylinder (in this case, there are four branch pipe parts because it is a four-cylinder engine),
First branch portions 26 from the gathering portion 22 to two branch pipe portions, respectively.
It consists of

The gathering portion 22 is composed of a bore portion 228 which is in continuous communication with the throttle bore 12, and a gathering chamber 22B below the bore portion 228. Second
In the figure, the first branch part 26 is connected to the collection chamber 22B of the collection part 22 at one end 268.

The center line of the passage of the first branch part 26 is set to the center line of the OB gathering part.
According to the invention, the first branch 26 is denoted by A.
At the connecting end 22A of the first collecting part 22, the center line 03 of the first branch part is offset by the collecting part center line ○A32, and this offset direction is the same as the injector center line O is offset from the throttle pore center line Oa. The direction is the same.

As mentioned above, due to the offset arrangement of the injector and the nozzle 18', the fuel from the injector 18 is distributed to the right side of the center line OA of the throttle bore 12, that is, to the right side of the center line OA of the collecting chamber, as indicated by F. It's coming down. However, the center line 03 of the first branch part 26 is offset at the joint end 22Δ with the gathering part 22, and
← The falling fuel flow is at the center line O of the first branch part 26 at the top.
Pass through B. Therefore, fuel passes through the center of the first branch 26 and is evenly distributed to the branch pipes 24, which in turn means that it is evenly distributed to each cylinder.

Effects of the Invention Since the air-fuel mixture is well distributed to each cylinder, smooth rotation with suppressed torque fluctuations is achieved. Furthermore, performance degradation and plug smoldering do not occur due to an abnormal air-fuel ratio in a particular cylinder.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the intake device of the present invention, and FIG. 2 is a plan view of the intake manifold taken along line nn in FIG. 1. 12... Throttle bore, 14... Throttle valve,
18... Injector, 20... Intake manifold,
22... Collecting part, 24... 2nd branch, 26... 1st branch, 0 work... injector center line, 0 post... center of slot notrebore, OA... center of collecting part, Oe...
・First branch center. Patent applicant Toyota Motor Corporation Patent application agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Takao Mitsui Patent attorney Akira Yama Iko Yamaya Masaya Nishiyama

Claims (1)

[Claims] A fuel injector is provided upstream of the throttle valve, and the center line of the injector is offset from the throttle bore center line on the side occupied by the lower half of the throttle valve when it is in an inclined position. An intake system for an internal combustion engine in which a center line of a branch pipe from a gathering part of an intake manifold is offset from a center line of the gathering part in a direction in which a center line of an injector is offset from a throttle bore center line.