JP2002317738A - Fuel injection device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a fuel injection device of an internal combustion engine for a motorcycle, and to reduce the intake resistance. SOLUTION: In this fuel injection device of the internal combustion engine provided with a first fuel injection valve 31 at a downstream side with respect to a throttle valve 27 of an intake pipe 20 and a second fuel injection valve 32 at an upstream side, the second fuel injection valve 32 is mounted at an upstream side with respect to an upstream side opening part of the intake pipe 20 at an interval, a central axis 33 of the second fuel injection valve 32 is inclined to a central axis 19 of the intake pipe 20, and an axis 34 in the fuel injection direction is inclined to the central axis 33 of the second fuel injection valve 32 to locate the axis 34 in the fuel injection direction approximately in parallel to the central axis 19 of the intake pipe 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device having a fuel injection valve provided upstream and downstream of a throttle valve of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as this kind, there is, for example, a technique disclosed in Japanese Patent Application Laid-Open No. Hei 10-196494.
This means that the nozzle portion of the first fuel injection valve is pulled in to the side downstream from the throttle valve in the intake pipe and attached, and the second fuel injection valve is positioned above the opening upstream of the throttle valve so that the axis of the injection direction is aligned. The opening is substantially parallel to the central axis of the intake pipe, and the ratio of the distance from the opening to the nozzle to the diameter of the opening is 0.5 or more.

As a result, the airflow resistance can be reduced, and despite the provision of the second fuel injection valve outside the intake pipe,
Atomized state can be maintained without wetting the wall of the intake pipe too much,
In addition, by surrounding the entire throttle body with an intake box, it is possible to prevent fuel vapor from scattering to the surroundings due to fuel injection.

[0004]

It is desirable that the second fuel injection valve used in the high-speed range is located at a position upstream of the intake pipe upstream opening in order to reduce intake resistance. However, in the above-mentioned conventional fuel injection device, the fuel system components such as the fixing member of the second fuel injection valve, the fuel pipe, and the wirings are present in the upstream direction of the intake pipe passage, and these are the intake resistance.
Further, since the second fuel injection valve is arranged substantially parallel to the central axis of the intake pipe, the height in the direction of the central axis of the intake pipe is increased.

[0005]

In order to solve the above-mentioned conventional problems, the invention according to claim 1 is directed to a first fuel injection valve downstream of a throttle valve of an intake pipe and a second fuel injection valve upstream of a throttle valve. In a fuel injection device for an internal combustion engine each including a fuel injection valve, the second fuel injection valve is installed at a distance upstream of an upstream opening of the intake pipe, and the second fuel injection valve is provided with a second fuel injection valve. The fuel injection with respect to the center axis of the second fuel injection valve is performed such that the center axis is inclined with respect to the center axis of the intake pipe, and the fuel injection direction axis is substantially parallel to the center axis of the intake pipe. A fuel injection device for an internal combustion engine, wherein a direction axis is inclined.

According to the first aspect of the present invention, since the central axis of the second fuel injector is inclined with respect to the central axis of the intake pipe, the second fuel injector is located upstream of the intake pipe. Even if it is installed with an interval upstream of the side opening,
The height of the intake pipe in the central axis direction can be reduced.
Further, since the fuel system component can be removed as much as possible from a region where the intake pipe passage extends to the upstream side, intake resistance can be reduced.

The fuel injection direction axis is inclined with respect to the center axis of the second fuel injection valve so that the fuel injection direction axis is substantially parallel to the center axis of the intake pipe. Therefore, although the center axis of the second fuel injection valve is inclined with respect to the center axis of the intake pipe, the amount of fuel attached to the inner wall of the intake pipe is small.

Next, a second aspect of the present invention is directed to the first aspect.
In the invention described in the above, the internal combustion engine is a V-type multi-cylinder engine, and fuel is supplied from a single fuel oil pipe installed between the V banks in parallel with the crankshaft axis to the second fuel injection valve of each cylinder. It is characterized by being supplied. Therefore, according to the second aspect of the invention, the fuel supply path to the second fuel injection valve can be shortened, and the mounting portion of the second fuel injection valve becomes compact.

[0009]

FIG. 1 is a left side view including a partial sectional view of a V-type internal combustion engine to which an embodiment of the present invention is applied, and FIG.
FIG. 3 is an enlarged cross-sectional view showing the upper part of FIG. 1, and FIG. 3 is a schematic diagram showing a fuel supply pipe in the present embodiment.

Referring first to FIG. 1, a multi-cylinder internal combustion engine E to which the present embodiment is applied is a DOHC type engine which is mounted on a motorcycle in a horizontal arrangement in which the axis of a crankshaft 8 is oriented in the left-right direction. It is a water-cooled V-type 4-cylinder 4-cycle internal combustion engine. The internal combustion engine E includes a cylinder block 1 having a front bank 1F and a rear bank 1R forming a V bank, a crankcase 2 coupled to a lower portion of the cylinder block 1, and upper ends of the front bank 1F and the rear bank 1R. Front cylinder head 3F, rear cylinder head 3R and front cylinder head 3F
And head covers 4F and 4R respectively coupled to the upper end of the rear cylinder head 3R.

In this embodiment, "front, rear, left and right" means "front, rear, left and right" with respect to a motorcycle as a vehicle.

Two cylinders 5F constituting the front bank 1F
A piston 6 is slidably fitted to the two cylinders 5R constituting the rear bank 1R and a combustion chamber 9 is formed between each piston 6 and each cylinder head 3F, 3R. Each cylinder head 3F, 3R has, for each cylinder 5F, 5R,
Intake port 10 having a pair of intake ports opening to combustion chamber 9
And an exhaust port 11 having a pair of exhaust ports opening to the combustion chamber 9, wherein the pair of intake ports and exhaust ports are:
A pair of intake valves 14 and a pair of valves respectively operated by an intake camshaft 12 and an exhaust camshaft 13 driven by the power of a crankshaft 8 rotatably supported between the cylinder block 1 and the crankcase 2. Is opened and closed at a predetermined timing by the exhaust valve 15.

Referring also to FIG. 2, an intake pipe 20 arranged inside the V-bank and connected to both cylinder heads 3F and 3R is an intake body 21 on which a first fuel injection valve 31 is mounted. And the throttle valve coupled to the intake body 21
27, and an air funnel 23 attached to the upstream end of each throttle body 22 for guiding air passing through an air cleaner (not shown) to the intake passage 25. Further, a frame trap 24 made of a wire mesh is attached to the air funnel 23 in order to prevent the flame from reaching the outside through the air cleaner when a backfire occurs. The intake passage 25 communicates with the intake ports 10 of the cylinder heads 3F, 3R.

A second fuel injection valve 32 is disposed above the frame trap 24 so that the tip is located at the opening 24a of the frame trap 24. The center axis 33 of the second fuel injection valve 32 is inclined by an angle α with respect to the center axis 19 of the inlet of the intake pipe 20. Also, the fuel injection direction axis 34 with respect to the center axis 33 of the second fuel injection valve 32 such that the injection direction axis 34 of the second fuel injection valve 32 is parallel to the center axis 19 of the intake pipe 20. It is provided at an angle.

In this embodiment, as shown in FIG. 3, each cylinder is connected via a delivery pipe 42 from a single fuel oil supply pipe 41 arranged between the V banks in parallel with the axis of the crankshaft 8. Fuel is supplied to the second fuel injection valve 32. Further, the fuel is sent to the fuel pipes 45 and 46 via the connecting pipe 44, and from there, is sent to the first fuel injection valve 31 of each cylinder. Note that in FIG.
47 is a regulator, and 48 and 49 are a diaphragm and a spring built in the regulator 47.

The fuel injected from the first fuel injection valve 31 and the second fuel injection valve 32 is mixed with the air sucked into each intake passage 25 to form an air-fuel mixture. The air-fuel mixture sucked into the combustion chamber 9 through each intake port 10 is ignited by an ignition plug 16 and burns, and the piston 6 reciprocates by the generated combustion pressure.
Drives the crankshaft 8 via the connecting rod 7.

In this embodiment, the center axis 33 of the second fuel injection valve 32 is inclined with respect to the center axis 19 of the inlet portion of the intake pipe 20. Despite the distal end being located upstream of the upstream opening of the intake pipe 20, the number of fuel system components protruding into the region 26 extending the intake passage 25 upstream can be reduced. Further, the height of the intake pipe 20 in the direction of the central axis 19 can be reduced. Therefore, the intake resistance can be reduced.

The injection direction axis 34 of the second fuel injection valve 32
The fuel injection direction axis 34 with respect to the center axis 33 of the second fuel injection valve 32 so that the fuel injection direction is parallel to the center axis 19 of the intake pipe 20.
, The amount of fuel attached to the inner wall of the intake pipe 20 is small even though the central axis 33 of the second fuel injection valve 32 is inclined with respect to the central axis 19 of the intake pipe 20.

Further, in the present embodiment, one fuel oil supply pipe disposed between the V banks in parallel with the axis of the crankshaft 8.
Since fuel is supplied from 41 to the second fuel injection valve 32 of each cylinder, the fuel supply path can be shortened, and the mounting portion of the second fuel injection valve 32 becomes compact.

[Brief description of the drawings]

FIG. 1 is a left side view including a partial cross-sectional view of a V-type internal combustion engine to which an embodiment of the present invention is applied.

FIG. 2 is an enlarged sectional view showing an upper part of FIG. 1;

FIG. 3 is a schematic diagram showing a fuel supply pipe in the present embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cylinder block, 1F ... Front bank, 1R ... Rear bank, 2 ... Crankcase, 3F ... Front cylinder head, 3R ... Rear cylinder head, 4F, 4R ... Head cover, 5F, 5R ... Cylinder, 6 ... Piston, 7 ... connecting rod, 8 ... crankshaft, 9 ... combustion chamber, 10 ... intake port, 11
... exhaust port, 12 ... intake camshaft, 13 ... exhaust camshaft, 14 ...
Intake valve, 15 ... Exhaust valve, 16 ... Spark plug, 19 ... Intake pipe center axis, 20 ... Intake pipe, 21 ... Intake body, 22 ... Throttle body, 23 ... Air funnel, 24 ... Frame trap, 24a
... opening, 25 ... intake passage, 27 ... throttle valve, 31 ... first
Fuel injection valve, 32: second fuel injection valve, 33: second fuel injection valve central axis, 34: fuel injection direction axis, 41: fuel oil supply pipe, 42
… Delivery pipe, 44… Connecting pipe, 45, 46… Fuel pipe, 47…
Regulator, 48 ... diaphragm, 49 ... spring, E
... internal combustion engine.

Claims (2)

[Claims] 1. A first valve located downstream of a throttle valve in an intake pipe.
In a fuel injection device for an internal combustion engine provided with a fuel injection valve and a second fuel injection valve on the upstream side, the second fuel injection valve is installed at an interval upstream of an upstream opening of the intake pipe. And the second fuel injection valve such that a center axis of the second fuel injection valve is inclined with respect to a center axis of the intake pipe, and a fuel injection direction axis is substantially parallel to a center axis of the intake pipe. Wherein the fuel injection direction axis is inclined with respect to the center axis of the fuel injection device. 2. The engine according to claim 1, wherein said internal combustion engine is a V-type multi-cylinder engine and is installed between V banks in parallel with a crankshaft axis.
2. The fuel injection device for an internal combustion engine according to claim 1, wherein fuel is supplied from the fuel supply pipe to the second fuel injection valve of each cylinder.