JP2951071B2 - Two-cycle multi-cylinder engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-cycle multi-cylinder engine having a fuel injection unit.

[0002]

2. Description of the Related Art In such a two-cycle multi-cylinder engine, between fuel injection units provided for each cylinder,
A damper housing accommodating a pulsation damper for suppressing fuel pulsation is provided, and the fuel passage and the air passage of the damper housing are connected to the fuel passage and the air passage of the fuel injection unit, respectively.

[0003]

However, in the conventional two-cycle multi-cylinder engine, since the fuel injection unit and the damper housing are directly connected,
Several types of damper housings had to be prepared in response to changes in the number and size of engines (displacement and cylinder bore pitch), leaving room for improvement in terms of common parts and cost reduction. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a two-cycle system that can cover a wide range of changes in the number of cylinders and cylinder bore pitches and can achieve commonality of parts and cost reduction. It is to provide a multi-cylinder engine.

[0005]

In order to achieve the above object, the present invention provides a fuel injection unit having a fuel passage, an air passage, and an opening / closing valve for opening and closing these passages in a cylinder head of each cylinder. In a two-cycle multi-cylinder engine including a damper housing having a fuel passage and an air passage therebetween, the fuel injection unit and the damper housing are detachably connected by a connecting member, and the fuel injection unit and the damper housing are connected to each other. It is characterized in that the fuel passage and the air passage are arranged on both sides with respect to the center line of the on-off valve.

[0006]

According to the present invention, since the fuel injection unit and the damper housing are detachably connected by the connecting member, the damper housing is made common, and the connecting member is not affected by changes in the number of cylinders of the engine and the cylinder bore pitch. It can be dealt with by adjusting the number and length. In particular, since the fuel passage and the air passage are distributed on both sides with respect to the center line of the on-off valve, the length of allowance for adjusting the length of the connecting member can be made larger than when these passages are arranged near the center line of the on-off valve. In addition, a common damper housing can be used for an engine having a small cylinder bore pitch, and the applicable range of the present invention can be expanded.

[0007]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 7 shows a two-cycle 3 according to the present invention.
Referring to FIG. 1, reference numeral 2 denotes a cylinder body, in which a cylinder head 3 is provided above the cylinder body.
The fuel injection unit 4 is attached to the cylinder head 3 for each cylinder.

In the cylinder body 2, three cylinders 5 are formed at appropriate intervals (cylinder bore pitch) in the direction perpendicular to the plane of FIG. 7, and a piston 6 is slidably fitted in each cylinder 5. Is equipped. Each piston 6 is connected to a crankshaft 7 via a connecting rod 6a. The crankshaft 7 is long in the direction perpendicular to the plane of FIG. 7 and is rotatably accommodated in the crankcase 8.

Further, a scavenging passage 9 and an exhaust passage 10 are formed in the cylinder body 2 for each cylinder, and these are opened in the cylinder 5 as a scavenging port 9a and an exhaust port 10a, respectively. Also, crankcase 8
The intake passage 11 is formed with a reed valve 12 and an intake pipe 13 connected to the intake passage 11.

On the other hand, the cylinder head 3 has a combustion chamber 1
4 is formed, and an ignition plug 15 whose discharge portion faces the combustion chamber 14 is screwed.

Here, the configuration of the fuel injection system is shown in FIGS.
It will be described based on. FIG. 1 is a plan view of a fuel injection system,
2 is a view in the direction of arrow A in FIG. 1, FIG. 3 is a view in the direction of arrow B in FIG. 1, FIG. 4 is an enlarged sectional view taken along line CC of FIG. 1, and FIG. FIG. 6 is a sectional view taken along line DD of FIG. 5, and FIG. 6 is a sectional view taken along line DD of FIG.

FIG. 4 shows the details of the construction of each of the fuel injection units 4. The housing 16 of the fuel injection unit 4 is connected to the cylinder head 3 (see FIG. 7). Held valve body 17
Is inserted into a circular hole 3a formed in the cylinder head 3 and its end face faces the inside of the combustion chamber 14 (FIG. 7).
reference).

An injection space 18 is formed in the center of the valve body 17, and an on-off valve 19 is accommodated in the injection space 18 so as to be vertically movable. And
A passage 20 communicates with the injection space 18, and an injector 21 is connected to the passage 20, and another passage 22 communicates with the passage 20. The lower surface of the injection space 18 is open to the combustion chamber 14 (see FIG. 7), and the lower surface opening is opened and closed at an appropriate timing by the on-off valve 19. The on-off valve 19 is driven by a solenoid 23.

In the housing 16, a fuel passage 24 and a space passage 25 which are long in the direction perpendicular to the paper of FIG. 4 are formed in parallel with each other, and are divided right and left with respect to the center line of the on-off valve 19. The fuel passage 24 and the air passage 25 are connected to the injection space 18 through the passages 20 and 22.
Is in communication with The offset amount of the air passage 25 with respect to the center line of the on-off valve 19 is set smaller than the offset amount of the fuel passage 24.

As shown in FIGS. 1 and 2, in this embodiment, the three fuel injection units 4 are juxtaposed in the length direction of the engine 1 (the direction in which the cylinders 5 are arranged) and are adjacent to each other. A damper housing 26 is provided between the fuel injection units 4.
Are arranged, and the damper housing 26 and the fuel injection unit 4 are detachably connected by pipe-like connecting members 27 and 28. That is, as shown in FIG. 5, a fuel passage 29 and an air passage 30 are formed in the damper housing 26, and the fuel passage 29 faces the pulsation damper 32 via the branch passage 31. As shown in FIG. 6, the air passage 30 is connected to a pulsation damper 32 through a ring-shaped passage 33 and four radial passages 34.
In the spring chamber 35. The fuel passage 29 and the air passage 30 of the damper housing 26 are connected to the connecting member 2.
7, 28, the fuel passage 24 of the fuel injection unit 4;
The fuel passages 24 and 29 and the air passages 25 and 30 are respectively connected to the air passage 25 in a straight line. FIG. 1 shows the fuel passages 24, 2
9, the center lines Lf and La of the air passages 25 and 30 are shown.

Here, the procedure for assembling the fuel injection system to the state shown in FIG. 1 will be described.

That is, first, the connecting members 27 and 28 are inserted into the respective fuel injection units 4 and the damper housing 26 to assemble the units. Next, the valve bodies 17 of the three fuel injection units 4 are applied to a jig (not shown), and the pitch between the valve bodies 17 is adjusted to the arrangement pitch of the three cylinders 5. The pitch at this time is adjusted by adjusting the press-fitting allowance of the connecting members 27 and 28.

Thereafter, the fuel injection unit 40 and the damper housing 26 are attached to the connecting plate 40 with a plurality of (in this embodiment, 15) bolts 14, and these are integrated as a unit. Finally, if the bolt 42 is inserted into the mounting boss of the fuel injection unit 4 and the unit is mounted on the cylinder head 3, the fuel injection system becomes as shown in FIG.
Assembled as shown. 1 and 3, the straight line O is the center line of the on-off valve 19.

As described above, in this embodiment, the fuel injection unit 4 and the damper housing 26 are connected to the connecting members 27 and 2.
8 so that the damper housing 26 can be shared by engines of different models (number of cylinders and cylinder bore pitch). That is, an increase or decrease in the number of cylinders is dealt with by an increase or decrease in the connecting members 27 and 28, and a change in the cylinder bore pitch causes a change in the connecting member 2.
Since it is possible to cope with this by adjusting the lengths of the dampers 7 and 28, the damper housing 26 can be used in common for various engines, and the cost can be reduced.

In this embodiment, the fuel injection unit 4, the fuel passages 24, 29 of the damper housing 26, and the air passages 25, 30 are distributed to the left and right with respect to the center line of the on-off valve 19. The margin for adjusting the length of the connecting members 27 and 28 (that is, the distance between the fuel injection unit 4 and the damper housing 26) can be made larger than when the cylinders are arranged in the vicinity of the center line. Also, a common damper housing 26 can be used, and the applicable range of the present invention can be expanded.

[0022]

As is apparent from the above description, according to the present invention, a fuel injection unit having a fuel passage, an air passage, and an on-off valve for opening and closing these passages is provided in the cylinder head of each cylinder. In a two-cycle multi-cylinder engine including a damper housing having a fuel passage and an air passage therebetween, the fuel injection unit and the damper housing are detachably connected by a connecting member, and the fuel injection unit and the damper housing are connected to each other. Since the fuel passage and the air passage are arranged separately on both sides with respect to the center line of the on-off valve, it is possible to cover a wide range of changes in the number of cylinders of the engine and the cylinder bore pitch, thereby achieving commonality of parts and cost reduction. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a fuel injection system of a two-cycle multi-cylinder engine according to the present invention.

FIG. 2 is a view in the direction of arrow A in FIG. 1;

FIG. 3 is a view in the direction of arrow B in FIG. 1;

FIG. 4 is an enlarged sectional view taken along line CC of FIG. 1;

FIG. 5 is a plan sectional view of the damper housing (EE of FIG. 2);
FIG.

FIG. 6 is a sectional view taken along line DD of FIG. 5;

FIG. 7 is a longitudinal sectional view of a two-cycle multi-cylinder engine according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 2 cycle multi-cylinder engine 3 Cylinder head 4 Fuel injection unit 19 On-off valve 24, 29 Fuel passage 25, 30 Air passage 26 Damper housing 27, 28 Connecting member

Claims (1)

(57) [Claims] A fuel injection unit having a fuel passage, an air passage, and an on-off valve for opening and closing them is provided in a cylinder head of each cylinder, and a fuel injection unit and a damper housing having an air passage are provided between the fuel injection units. Set up 2
In the cycle multi-cylinder engine, the fuel injection unit and the damper housing are detachably connected by a connecting member, and the fuel passage and the air passage of the fuel injection unit and the damper housing are distributed to both sides with respect to the center line of the on-off valve. A two-cycle, multi-cylinder engine characterized by being arranged.