JPH05164023A - Air intake system in fuel injection device for engine - Google Patents

Abstract

PURPOSE:To secure a flow rate of air introduced to an injector at the time of acceleration and to sufficiently display an air mixture function by providing the injector in the middle of an air intake pipe, a pump part, a first and a second check valve in the middle of an introduction tube for air mixture and a valve body inside of the pump part. CONSTITUTION:In a fuel injection device of an engine 2 with an injector 14 to inject and supply fuel, the injector 14 is provided in the middle of an air intake passage 8 on the downstream side of a throttle valve 12, a starting end is opened on the air intake passage 8 on the upstream side of the throttle valve 12 and an introduction tube 16 for air mixture to open a rear end is provided on the injector 14. Thereafter, a pump part 18 is provided in the middle of this introduction tube 16 for air mixture, a first and a second check valves 20, 22 to allow flow of air only from the side of a starting end 16a to the side of a rear end 16b are provided on the upstream and the downstream points of this pump part 18 and a valve body 24 to actuate to force out air inside of the pump part 18 to the side of the injector 14 by way of interlocking with the throttle valve 12 at the time of acceleration is provided inside of the pump part 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an engine fuel injection device, and more particularly to an intake system for an engine fuel injection device that injects fuel into an engine by an injector.

[0002]

2. Description of the Related Art An engine fuel injection system is provided with an injector for injecting fuel into the engine.
In this injector, the multi-point type in which the number of injectors corresponding to the number of cylinders is arranged to supply the mixed air flow to each combustion chamber which is each cylinder of the engine, or the mixed air flow from one injector is supplied to each combustion chamber There is a single point formula that branches to.

An example of the fuel injection device for the engine is disclosed in Japanese Utility Model Laid-Open No. 60-183272. The fuel supply device for an internal combustion engine disclosed in this publication is
A plurality of fuel injection nozzles that inject fuel at a predetermined pressure when energized are provided in the branch manifold, and a plurality of divergent nozzles that increase in cross section toward the fuel injection direction after the cross-sectional area decreases are provided in front of the injection ports of each fuel injection nozzle. An air introduction path for introducing air is provided between the nozzle and the injection port, and a main throttle valve that controls the intake air amount is arranged in a collecting pipe that collects the branch manifolds. A plurality of sub-throttle valves are arranged in the branch manifold upstream of the fuel injection nozzle, and an air amount corresponding to the pressure difference between each sub-throttle valve upstream and downstream is supplied to the air introduction passage.

[0004]

By the way, in the intake system of the conventional engine fuel injection system,
As shown in FIG. 4, the intake pipe 1 connected to the engine 102
Air is introduced into the injector 114 by utilizing the negative pressure difference between the upstream and downstream portions of the throttle valve 112 in 06.

In this intake system, an intake pipe 106 is connected to the engine 102, and a throttle valve 112 and an injector 114 are arranged in an intake passage 108 in the intake pipe 106 from the upstream side.

An air mixing inlet pipe 116 is provided in the intake passage 108 on the upstream side of the throttle valve 112, with a starting end 116a opening and a terminal end 116b opening near the injector 114.

However, at the time of acceleration, the throttle valve 1
When the throttle opening of 12 becomes large, the negative pressure difference between the upstream and downstream of the throttle valve 112 becomes small, and as shown in FIG.
The flow rate of air passing through the air mixing introducing pipe 116 is also reduced.

As a result, there is a disadvantage that the air mixing of the injector cannot be performed well due to the decrease of the air flow rate passing through the air mixing introducing pipe, the air mixing function cannot be sufficiently exerted, and it is disadvantageous in practical use. .

In addition, as an intake system in a fuel injection system for an engine, air is introduced into an injector by an acceleration pump that utilizes the driving force of the engine or electric energy from a motor or the like.

As shown in FIG. 6, this intake system is provided with an air mixing introducing pipe 216 having a starting end 216a opening in the intake passage 208 upstream of the throttle valve 212 and an end 216b opening in the vicinity of the injector 214. At this time, the acceleration pump 230 is provided in the middle of the air mixing introduction pipe 216.

Then, the acceleration pump 230 is driven by the driving force of the engine or the electric energy, and sufficient air is introduced to the injector 214 side during acceleration by the acceleration pump 230.

However, since the acceleration pump is driven by the driving force and electric energy of the engine, the output loss of the engine becomes large, which is disadvantageous in practical use, and the fuel consumption deteriorates. There is an inconvenience of being disadvantageous.

[0013]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention is directed to an engine fuel injection apparatus having an injector for injecting and supplying fuel to the engine. An injector is provided, an air mixing introduction pipe is provided which opens at the intake passage upstream of the throttle valve and ends at the injector, and a pump portion is provided in the middle of the air mixing introduction pipe. First and second check valves that allow the flow of air only from the start end side to the end side are provided, and operate in the pump unit in cooperation with the throttle valve to push out the air in the pump unit to the injector side during acceleration. It is characterized in that a valve body is provided.

[0014]

By inventing as described above, during acceleration,
The valve body in the pump unit is operated in conjunction with the throttle valve to push the air in the pump unit to the injector side and introduce the air into the injector to achieve good air mixing of the injector.

[0015]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 3 show an embodiment of the present invention. In FIG. 1, 2 is an engine, 4 is an air cleaner, 6 is an intake pipe, 8 is an intake passage, and 10 is an exhaust passage.

An air cleaner 4 is connected to the engine 2 via an intake pipe 6, an intake passage 8 is formed in the intake pipe 6, and a throttle valve 12 is arranged in the intake passage 8.

Further, an injector 14 is provided in the middle of the intake passage 8 downstream of the throttle valve 12, and the intake passage 8 upstream of the throttle valve 12 is provided.
The injector 14 is provided with an air mixing introducing pipe 16 having an opening at the starting end 16a and an opening at the ending end 16b.

A pump portion 18 is provided in the middle of the air mixing introducing pipe 16, and air is allowed to flow only from the start end 16a side to the end end 16b side of the air mixing introducing pipe 16 at the upstream and downstream parts of the pump portion 18. First and second check valve 2
Nos. 0 and 22 are provided, respectively, and a valve body 24 that operates to push the air in the pump unit 18 toward the injector 14 side in association with the throttle valve 12 at the time of acceleration is provided in the pump unit 18.

More specifically, an approximately 1/4 circular pump portion 18 is provided in the middle of the air mixing introducing pipe 16, and a start end 16a of the air mixing introducing pipe 16 upstream of the pump portion 18 is provided.
The first check valve 20 is provided on the side, and the end 16b of the air mixing introducing pipe 16 on the downstream side of the pump portion 18 is provided.
A second check valve 22 is provided on the side.

Further, the valve body 24 is arranged so that a portion near the intersection of two straight lines having a substantially 1/4 circular shape is a rotation center and a circumferential side is a rotation front end portion. A connecting rod 26 is connected to the throttle valve 12.

Next, the operation will be described.

When the throttle valve 12 is fully closed, for example, during steady operation in which the throttle opening does not change with time, as shown in FIG. Due to the large negative pressure difference in the intake pipe 8, air flows in from the starting end 16a of the air mixing introduction pipe 16.

The air is supplied to the first check valve 20,
The pump portion 18 and the second check valve 22 are sequentially passed, and then the end 16b of the air mixing introducing pipe 16 is connected to the injector 14
Will be introduced to.

Further, at the time of acceleration in the operating state where the throttle valve 12 is fully opened, as shown in FIG. 3, the valve body 2 in the pump portion 18 is interlocked with the operation of the throttle valve 12.
4 is rotated.

At this time, the negative pressure difference in the intake passage 8 upstream and downstream of the throttle valve 12 is small, and the inflow of air from the starting end 16a of the air mixing introducing pipe 16 cannot be expected.

When the valve body 24 is rotated, the air in the pump portion 18 is pressed by the valve body 24 and flows from the second check valve 22 which can be circulated to the air mixing inlet pipe 1.
The air is supplied to the injector 14 by being pushed out to the other end 16b of the No. 6 side.

As a result, the injector 1 during steady operation
4 can be introduced in the same manner as in the case of utilizing a conventional negative pressure difference, and at the time of acceleration, the air inside the pump portion 18 is pushed out by the valve body 24 that interlocks with the throttle valve 12, and the air is introduced into the injector 14. It can be introduced, and the flow rate of the air introduced into the injector 14 at the time of acceleration can be sufficiently secured, and the air mixing function of the injector 14 can be exhibited well.

Further, when the valve body 24 is operated, the throttle valve 12 is connected by the connecting rod 26 so as to be interlocked with each other. There is no loss of engine output, it is possible to reliably prevent the engine output from decreasing, and it is practically advantageous, and it is possible to avoid deterioration of fuel consumption and it is economically advantageous.

Further, since the pump portion 18, the valve body 24, and the connecting rod 26 are relatively simple in structure, they can be manufactured easily and the cost can be kept low.

[0031]

As described in detail above, according to the present invention, an injector is provided in the middle of the intake passage on the downstream side of the throttle valve of the fuel injection device of the engine, and the injector is opened at the start end in the intake passage on the upstream side of the throttle valve. First and second check valves which are provided with an air mixing introduction pipe opening at the end, a pump portion is provided in the middle of the air mixing introduction pipe, and air is allowed to flow only from the start end side to the end side in the upstream and downstream parts of the pump portion. Since a valve element that operates to push the air inside the pump section toward the injector side in conjunction with the throttle valve at the time of acceleration is provided in the pump section, the introduction of air to the injector during steady operation can reduce the conventional negative pressure difference. It can be performed in the same way as the one used, and the air inside the pump is pushed out by the valve body that works in conjunction with the throttle valve during acceleration. Can the air flow to be introduced to the injector at the time of acceleration is introduced into the injector-obtained sufficiently secured, to satisfactorily exhibit the air mixing function of the injector. Further, when the valve element is operated, the throttle valve is connected and interlocked with each other, so that there is no engine loss output compared to the conventional one that utilizes the engine output or electric energy, It is possible to prevent a decrease in fuel consumption, which is practically advantageous, and it is possible to avoid deterioration of fuel efficiency, which is economically advantageous.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an intake system in a fuel injection device for an engine showing an embodiment of the present invention.

FIG. 2 is a schematic enlarged view of a pump unit and a valve body when the throttle valve is fully closed.

FIG. 3 is a schematic enlarged view of a pump unit and a valve body when the throttle valve is fully opened.

FIG. 4 is a schematic diagram of an intake system in an engine fuel injection device showing one conventional technique of the present invention.

FIG. 5 is a diagram showing a relationship between an intake negative pressure, which is a negative pressure difference upstream and downstream of a throttle valve, and an air flow rate in an air mixing introduction pipe.

FIG. 6 is a schematic view of an intake system in an engine fuel injection device showing another conventional technique of the present invention.

[Explanation of symbols]

 2 engine 8 intake passage 10 exhaust passage 12 throttle valve 14 injector 16 air mixing introduction pipe 16a start end 16b end 18 pump part 20 first check valve 22 second check valve 24 valve body 26 connecting rod

Claims (1)

[Claims] 1. A fuel injection system for an engine, comprising an injector for injecting fuel into an engine, wherein the injector is provided midway in an intake passage downstream of a throttle valve, and the injector is provided with a starting end opening in the intake passage upstream of the throttle valve. An air mixing introduction pipe having a terminal opening is provided, a pump portion is provided in the middle of the air mixing introduction pipe, and air is allowed to flow only from the start end side to the end side in the upstream and downstream parts of the pump portion. An intake system in a fuel injection system for an engine, characterized in that a check valve is provided, and a valve body that operates to push air in the pump section toward the injector side in association with the throttle valve during acceleration is provided in the pump section. .