JPH0442528Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a throttle body for a fuel injection device used in an internal combustion engine, and in particular has a main injection valve and a sub-injection valve on the upstream and downstream sides of the throttle valve. The present invention relates to a throttle body for a fuel injection device.

<Prior Art> In recent years, there has been a trend toward adoption of a throttle body injection system (single point injection) in which an injection valve is provided in a throttle body provided in an intake passage as a fuel injection device for an internal combustion engine. In particular, a throttle body with an air valve and a throttle valve arranged on the upstream and downstream sides of the intake duct, respectively, uses the air valve to restrict the air flow to a certain extent even when the engine is running at low speed, similar to a variable bench lily. The following effects can be obtained, and fuel can be atomized over a wide operating range.

In addition, in order to widen the dynamic range of the fuel injection amount, for example, as disclosed in Japanese Patent Publication No. 60-53783, fuel injection valves are provided on the upstream and downstream sides of the throttle valve, respectively, to increase the fuel injection amount. It is better to accurately control the process according to a predetermined schedule. However, when the engine speed is low and the amount of intake air is low, such as during idling, the fuel is injected into the intake air flow at a relatively low speed, so some of the fuel may adhere to the wall of the intake passage around the injection valve. Atomization tends to be incomplete, and in particular, the distribution of fuel to the intake manifold becomes a problem. Also, JP-A-58-
According to Japanese Patent No. 18555, it is generally known that a more appropriate atomization form of the injected fuel can be obtained by changing the mounting position of the injection valve, and that the atomization characteristics can be improved.

<Problems to be solved by the invention> Therefore, the purpose of the invention is to provide sufficient diffusion of the injected fuel from the sub-injection valve, which is disposed downstream of the throttle valve and is activated for injection at least during engine idling. The present invention aims to provide a throttle body for a fuel injection device that improves atomization and distribution to an intake manifold.

<Means for Solving the Problems> According to the present invention, the above-mentioned object is achieved by providing an injection valve that injects fuel into an intake passage installed in a body main body, and an injection valve provided at a position on the downstream side of the intake passage. 1. A throttle body for a fuel injection device, comprising a throttle valve and an air valve provided in an intake passage upstream of the throttle valve to open and close the intake passage in response to intake negative pressure, the injection valve being , a main injection valve provided in a first fuel injection passage that opens into the intake passage on the upstream side of the throttle valve, and a main injection valve provided in a second fuel injection passage that opens into the intake passage on the downstream side of the throttle valve, It consists of a sub-injection valve that is activated to inject at least when the engine is idling,
The nozzle tip of the sub-injection valve is disposed further away from the inner wall surface of the intake tract than the nozzle tip of the main injector, and the inner wall surface of the intake tract extends from the second fuel injection passage downstream to the lower end of the body main body. This is achieved by providing a throttle body for a fuel injection device, which is characterized in that a notch is formed therein.

<Operation> With this configuration, the fuel injected from the sub-injection valve is supplied into the intake passage in a sufficiently diffused state.

<Embodiments> The present invention will now be described in detail with reference to specific embodiments with reference to the accompanying drawings.

As shown in FIG. 1, a throttle body 1 according to the present invention has an intake passage 3 disposed inside a main body 2 thereof. An air valve 4 is rotatably supported at an offset position by a valve shaft 5 on an upstream side 3a of the intake path that communicates with an air cleaner (not shown), and a downstream side 3c of the intake path that communicates with an intake manifold (not shown). A throttle valve 6 is rotatably supported by a valve shaft 7. In addition, the air valve 4 and the throttle valve 6 of the intake path 3
A narrow portion 3b serving as a fixed bench lily is provided approximately in the middle between the two.

A pair of injection passages 8 and 9 are provided on one side of the body main body 2 and open obliquely toward the downstream side of the intake passage 3. A main injection valve 10 and a sub-injection valve 11 are installed inside the injection passages 8 and 9, respectively. The outer opening of each injection passage 8, 9 is closed by a cap 12, 13, respectively, and each injection valve 10, 11 is closed by a holding plate 14, 15.
is held in place. In addition, the sub-injection valve 11
The nozzle portion 16 is fitted and held within a cylindrical member 17 fixed within the injection passage 9.

The intake passage 3 side opening 8a of the injection passage 8 is provided at a position facing the rear edge 4b of the air valve 4, that is, the downstream edge, and the nozzle tip 10a of the main injection valve 10 is located at the front edge of the throttle valve 6. It is arranged toward the portion 6a, that is, the upstream edge. A notch 4a is provided in a portion of the air valve 4 adjacent to the injection passage 8.
Interference between the fuel injected from the main injection valve 10 and the air valve 4 is avoided. The intake passage 3 side opening 9a of the injection passage 9 is provided slightly downstream of the throttle valve 6, and the nozzle tip 11a of the sub-injection valve 11 is located slightly downstream of the throttle valve 6.
The nozzle tip 10a of the main injection valve 10 is arranged at a distance from the inner wall surface of the intake passage 3. The opening 9a of the injection passage 9 is provided with a semicircular cutout 18 that extends to the lower surface of the body main body 2. As a result, the injected fuel from the sub-injection valve 11 is transferred to the passage 9.
It does not hit the wall surface, and the atomization form can be made wider, and even during low-load operation where the intake air flow rate is relatively slow, it is sufficiently diffused and distribution performance is improved.

An assist air passage 19 extending from slightly upstream of the narrowed portion 3b to the injection passage 9 is provided inside the main body 2. The assist air passage 19 opens near the nozzle portion 16 of the sub-injection valve 11, and the jet 20 is fitted into the opening end. Air introduced from the assist air passage 15 reaches the nozzle tip 1 through a gap 21 formed between the nozzle part 16 and the member 14.
The fuel is guided to the vicinity of 1a and is strongly mixed with the fuel injected from the sub-injection valve 11, thereby promoting atomization. The jet 20 is selected to ensure the minimum amount of air necessary. This jet 20 allows the fuel passage 9
The flow rate of air introduced into the chamber is stably controlled and the flow velocity is increased, promoting the swirl effect.
Atomization of fuel from the sub-injector 11 is further improved.
Further, a part of the fuel from the main injection valve 10 flows into the assist air passage 19 together with the air, and carbon and the like adhering to the passage 19 and the gap 21 are cleaned. Furthermore, the same effect can be obtained by forming the opening end to the injection passage 9 with a hole having a considerably small diameter instead of using the separate jet 21 as described above.

The main injection valve 10 has a fuel inlet 22 opened at its outer periphery. O-rings 23 and 24 are fitted on the nozzle side and the upper outer peripheral surface with the fuel inlet 22 in between. These O-rings 23 and 24 provide a seal between the wall surface of the passage 8 and the outer periphery of the main injection valve.
Fuel is supplied from an external fuel supply pipe (not shown) into the injection passage 8 between the sealed O-rings 23 and 24, and is introduced into the main injection valve 10 through the fuel inlet 22 and from the nozzle tip 10a. It is injected into the intake duct 3. The nozzle side O-ring 23 has approximately the same diameter as the upper O-ring 24, but is slightly smaller in diameter. Also, both O-rings 2
A stepped portion 2 is formed in the injection passage 8 according to the diameter difference between the diameters 3 and 24.
5 is formed. Therefore, when the injection valve 10 is installed, the distance that the O-ring 23 makes sliding contact with the wall surface of the passage 8 is relatively short, and there is no risk of it being damaged or cut. Similarly, a fuel inlet 26 is provided on the outer periphery of the sub-injector 11, and O-rings 27 and 28 are fitted with the fuel inlet 26 in between.

A link member 30 is fixed to the outer end of the valve stem 5, and a connecting rod 3 is connected to the free end 30a of the link member 30.
1 to a negative pressure actuator 32. On the other hand, a negative pressure outlet port 33 is provided near the narrowed portion 3 b of the intake passage 3 and communicates with a negative pressure chamber 35 of the negative pressure actuator 32 via a conduit 34 . This negative pressure extraction port 33 is opened near the narrowed portion 3b on the opposite side of the rear edge portion 4b where the notch portion 4a of the air valve 4 is provided. Therefore, air valve 4
As a result, a relatively stable and high operating negative pressure can be obtained without being affected by turbulence generated in the intake tract on the downstream side. Furthermore, since the negative pressure outlet port 33 is inclined toward the downstream side, fuel injected from the main injection valve 10 may flow into the negative pressure actuator 32 from the negative pressure outlet port 28 and damage the diaphragm 36. There isn't. However, it goes without saying that even if the negative pressure outlet port 28 is opened perpendicularly to the intake passage 3, a similarly stable and high operating negative pressure can be obtained.

Furthermore, if a solenoid valve is provided between the negative pressure outlet port 33 and the conduit 34, it will be activated depending on the operating conditions of the engine, and the air valve will be closed when the engine is cold or at low rotation speeds, allowing the fuel to be misted. This is preferable because it can further improve the conversion rate.

The diaphragm 36 is connected to one end of the connecting rod 31 via a retainer 37, and normally the air valve 4 is moved to the fully closed position via a link member 30 connected to the other end of the rod 31 by a compression coil spring 38. is energized. When negative pressure is generated near the narrowed portion 3b, the air valve 4 is driven to open in the direction of arrow A in the figure in response to the negative pressure. That is, in the fully closed position shown by the solid line in the figure, the air valve 4 has the leading edge 6a on the side opposite to the main injection valve 10 and the trailing edge 6b on the side of the main injection valve 6b. The edge portion 4b is opened in a direction away from the main injection valve 10 to a fully open position shown by a phantom line 39.

A torsion coil spring, a throttle lever, etc. (not shown) are attached to the outer end of the valve shaft 7 of the throttle valve 6, and the throttle valve 6 is operated by a throttle pedal or the like in a manner known per se.
Similarly, the valve is driven to open in the direction of arrow B in the figure. That is, like the air valve 4, the throttle valve 6 is in the fully closed position shown by the solid line in the figure, with the leading edge 6a facing away from the main injection valve 10 and the trailing edge 6b facing the main injection valve 6b. At the same time, the trailing edge portion 6b is opened in a direction away from the main injection valve 10 to a fully open position shown by an imaginary line 40.

In this way, the air edge 4 and the throttle valve 6
receive injected fuel from the main injection valve 10 on each upper surface thereof. Furthermore, as described above, since the nozzle tip 10a of the main injection valve 10 is disposed toward the front end 6a of the throttle valve when the throttle valve is fully closed, fuel can be injected even when the throttle valve is opened at a low or high opening. is diffused substantially uniformly into the intake air flow flowing through the intake passage 3.

Further, the valve shaft 7 of the throttle valve 6 has a cutout groove 7a formed on its upper surface side. As a result, the injected fuel is not accumulated on the upper surface of the throttle valve 6, but is diffused into the intake air flow, and is sent from the intake manifold to the fuel chamber. Instead of the notched groove 7a of the valve stem 7, other known means may be used, such as splitting the valve stem itself flat or forming a groove on the upper surface of the throttle valve 6.

<Effects of the invention> As described above, according to the invention, the nozzle tip of the sub-injection valve on the downstream side of the throttle valve is separated from the inner wall surface of the intake tract and is located deeper than the nozzle tip of the main injector on the upstream side of the throttle valve. Due to this arrangement, the fuel injected from the sub-injection valve into the low-speed intake air flow is sufficiently diffused, improving atomization, and the notch prevents the injected fuel from adhering to the wall surface of the injection passage. Since there is no variation in the air-fuel mixture, the distribution to the intake manifold is improved. This improves stability, especially when the engine is running at low speeds or when running at idle.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a throttle body for a fuel injection device based on the present invention. Figure 2 shows the first
FIG. 3 is a bottom view of the illustrated throttle body. 1...Throttle body, 2...Body body,
3... Intake duct, 3a... Upstream side, 3b... Constriction part, 3c... Downstream side, 4... Air valve, 4a... Notch part, 4b... Trailing edge part, 5... Valve shaft, 6 ...throttle valve, 6a...front edge, 6b...rear edge, 7
... Valve shaft, 7a ... Notch groove, 8 ... Injection passage, 8
a...opening, 9...injection passage, 9a...opening, 10...main injection valve, 10a...nozzle tip,
11...Sub-injection valve, 11a...Nozzle tip, 1
2, 13... Cap, 14, 15... Presser plate, 16... Nozzle part, 17... Cylindrical member,
18... Notch, 19... Assist air passage, 2
0... Jet, 21... Gap, 22... Fuel inlet, 23, 24... O-ring, 26... Fuel inlet, 27, 28... O-ring, 30... Link member, 30a... Free end, 31...Connection rod, 3
2...Negative pressure actuator, 33...Negative pressure outlet port, 34...Pipe line, 35...Negative pressure chamber, 36...
...Diaphragm, 37...Retainer, 38...Compression coil spring, 39, 40...Imaginary line.

Claims (1)

[Claims for Utility Model Registration] An injection valve that injects fuel into an intake passage installed in the body, a throttle valve installed downstream of the intake passage; A throttle body for a fuel injection device having an air valve provided in an intake passage upstream of the throttle valve to open and close a passage, the injection valve opening into the intake passage upstream of the throttle valve. a main injection valve provided in a first fuel injection passage; and a second fuel injection passage opened into an intake passage downstream of the throttle valve;
The sub-injection valve is configured to include at least a sub-injection valve that is activated to inject when the engine is idling, and a nozzle tip of the sub-injection valve is disposed further away from the inner wall surface of the intake tract than a nozzle tip of the main injection valve, and A throttle body for a fuel injection device, characterized in that a notch is formed extending downstream from the second fuel injection passage to the lower end of the body main body.