JPS60108528A - Compressing device for precombustion chamber - Google Patents

Abstract

PURPOSE:To enable stable operation of an engine, by a method wherein a positive motion cam for driving a compression piston is mounted to a cam shaft turning in linkage with the crank shaft of an internal combustion engine. CONSTITUTION:A precombustion chamber 27 communicated with a main combustion chamber 22 is formed. Uniform fuel-air mixture, sucked in the main combustion chamber 22 and fed in the precombustion chamber 27, is independently compressed by means of a compression pisting 13 for combustion. Combustion gas in the precombustion chamber 27 is injected in the main combust on chamber 22 by means of a compression pressure, and the uniform fuel-air mixture in the main combustion chamber 22 is burnt. A cam shaft turning in linkage with the crank shaft of an internal combustion engine is mounted, and a positive motion cam for driving the compression piston 13 is attached to the cam shaft. This prevents the occurrence of operating lag of the compression piston and enables stable operation of an engine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compression device for a pre-combustion chamber in an internal combustion engine,
In particular, the present invention relates to a compression device in which a compression piston disposed in a pre-combustion chamber is driven by a cam.

The applicant of the present application previously provided an internal combustion engine equipped with a pre-combustion chamber (Japanese Patent Application No. 37950/1982). This internal combustion engine is equipped with a pre-combustion chamber that communicates with the main combustion chamber, and the homogeneous air-fuel mixture that is sucked into the main combustion chamber and further flows into the pre-combustion chamber is independently compressed by a compression piston installed in the pre-combustion chamber. The combustion gas in the pre-combustion chamber is injected into the main combustion chamber by the combustion pressure, thereby combusting the homogeneous air-fuel mixture in the main combustion chamber.

The present invention provides a novel pre-combustion chamber compression device for such an internal combustion engine.

An embodiment in which the present invention is applied to a two-stroke engine will be described below with reference to the drawings. FIG. 1 shows a cylinder head portion of an engine, in which 1 is a cylinder and 9 is a piston. 1. The upper end opening 1a of the cylinder 1 is hermetically closed by a head 3 attached to the upper end of the cylinder 1 with a bolt 2.

The head 3 has a bottom wall 3a extending horizontally and a side wall 3b extending vertically, and a compression device 4 is disposed on the bottom wall 3a. Further, the upper end opening 3c of the head 3 is hermetically closed by a cover 7 attached with a screw 6 with a gasket 5 in between, thereby forming an airtight chamber 8 inside the head 3. A predetermined amount of lubricating oil (not shown) is stored inside the head 3, and the amount of this lubricating oil can be checked using an oil level gauge 10.

Further, a blind bolt 11 is screwed into the head bottom wall portion 3a, so that the lubricating oil can be replaced as necessary.

The compression device 4 mainly consists of a cylinder block 12.degree. compression piston 13. Cam14. It is composed of a tappet 15 and a combustion adjustment valve 16. The above cylinder block I
2 is disposed directly above the cylinder 1, and is fixed to the bottom wall portion 3a of the head 3 with bolts 17. Inside this cylinder block 12, a cylinder hole 18 and a valve hole 19 are provided.
are perforated horizontally on the same axis, and these cylinder holes 18 and valve holes 19 communicate with each other through a nozzle hole 52, and the intake passage 2o and the ejection passage 21
and communicate with the main combustion chamber 22 in the cylinder 1, respectively. The intake port 23 formed in the head bottom wall portion 3a is preferably located in a relatively high temperature part of the combustion chamber 22, thereby making it easier to warm up the engine at low temperatures. Further, the position of the jet nozzle 24 formed in the head bottom wall 3a is preferably located at the center of the combustion chamber 22, thereby making it possible to average the flame propagation time within the combustion chamber 22. . Note that the first
In the figure, reference numerals 25 and 26 designate gaskets fitted to the connection portions of the intake port 23 and the jet port 24, respectively.

A compression piston 13 is slidably and rotatably inserted into the cylinder hole 18 as shown in FIG. 1, and a pre-combustion chamber is provided in front of the piston 13 (to the left in FIGS. 27 is formed. This compression piston 13 is
Specifically, as shown in FIG. 2, there is a hollow piston body 29 with a dish portion 28 formed at one end, and a cap-shaped piston head 30 screwed onto the outer periphery of the other end of the piston body 29.
It consists of A guide 31 is rotatably fitted to the outer periphery of one end of the piston body 29, and a thrust bearing 32 is fitted between the guide 31 and the plate portion 28.

The guide 31 includes a cylindrical portion 31a extending toward the piston toward the Rad 22, and a ring-shaped bearing holding portion 31b.
The cylindrical portion 23 is slidably inserted into the outer periphery of the cylindrical portion 12a formed at one end of the cylinder block 12. Further, one side plate 32a of the thrust bearing 32 is fitted into the inner periphery of the bearing holding portion 31b.

In FIG. 2, 33 is a large oil hole formed along the axial direction within the piston body 29, and 34 is a plurality of small oil holes similarly formed along the radial direction. Reference numeral 35 denotes a plurality of first passages which are diagonally perforated from the vicinity of the entrance part 33a of the large oil hole 33 toward the surface of the dish part 28, and which are connected to the tappet 1.
Is the inlet portion 33a blocked by the tip of No. 5 moist? lk
It is a bad idea to introduce Ura. Further, 36 and 37 are second passages passing through the piston body 29 and the guide 31 in the radial direction, and 38 is a third passage extending from the second passage 37 toward the inside of the cylindrical portion 31a. The passage 37 and the third passage 38 function as a supply passage for lubricating oil to the inner peripheral surface of the cylindrical part 31a, and also function as a ventilation hole for the inner space of the cylindrical part 31a when the cylindrical part 31a slides. It is composed of Further, 39 and 40 are piston rings.

A spring receiving ring 44 is fitted and fixed to the base end of the cylindrical portion 12a of the cylinder block 12, as shown in FIG. And this spring bearing ring 44 and compression piston 13
A compression spring 45 is disposed between the piston 13 and the guide 31, and the piston 13 is constantly urged in the direction of arrow a in FIG. On the other hand, a tappet 15 is disposed between the dish portion 28 of the compression piston 13 and the cam 14. This tappet 15 includes a shaft portion 15a and a shaft portion 15a.
A plate portion 15b formed at one end is formed, and a shaft portion 15a is formed.
is slidably and rotatably inserted into a guide hole 48 of a guide 47 fixed to the head bottom wall 3 a with a bolt 46 . The tip of the shaft portion 15a is connected to the compression piston 1.
The tapered portion 15b of the taperoid 5 is in contact with the outer peripheral surface of the cam 14.

The cam 14 has a fan shape and is fixed to a cam shaft 51 disposed in the horizontal direction (in the front-rear direction in FIG. 1). This camshaft 51 is connected to the crankshaft of the engine via a transmission means such as a gear (not shown), and is configured so that when the crankshaft rotates once, the camshaft 51 also rotates once. There is. Note that the center line L1 of the cam 14 is as shown in FIG. 3 (the center line of the tappet eye 5).

The arc portion 1 of the cam 14 is arranged slightly shifted from the
The tappet 15 rotates little by little due to the friction between the tappet 4a and the dish portion 15b of the tappet 15, and this rotation causes the compression piston 13 to rotate as well, thereby preventing the compression piston I3 from seizing.

The precombustion chamber 27 within the cylinder hole 18 is communicated with the tip of the valve hole 19 through a nozzle hole 52, as shown in FIGS. 1, 4, and 5. A combustion adjustment valve 16 biased in the direction of the arrow by a spring 53 is slidably inserted into the valve hole 19 as shown in FIG. is occluded by the tip of the However, in the middle part of the combustion adjustment valve 16,
As shown in the figure, a flange-shaped stopper part 54 is formed, and when this stopper part 54 comes into contact with the side wall 12b of the cylinder block 12, a fifth As shown in the figure, it is constructed so that only a few gaps remain.

This gap A is to prevent the nozzle hole 52 from being blocked by carbon etc.
In order to prevent a pressure drop, the gap is preferably 0.01 mm or less. The outer circumferential surface 55 on the outlet side of the nozzle 'R, , 52 is shaped like a truncated cone as shown in FIG.
6 is formed so that the air-fuel mixture in the pre-combustion chamber 27 during compression is unlikely to leak into the ejection passage 21.

A spring 53 biasing the combustion regulating valve 16 is housed in a cylindrical case 59 attached to the head side wall 3b with a nut 5B as shown in FIG. This cylindrical case 5
An insertion hole 60 through which the combustion adjustment valve 16 is inserted is formed at one end of the spring 9, and an adjustment bolt 61 that directs one end of the spring 53 is screwed into the other end. By adjusting the rotation of this adjustment bolt 61, the setting force of the spring 53 can be adjusted. A fixing nut 62 for preventing loosening is screwed onto the adjustment bolt 61.

There is a tapped hole 6 in the adjustment bolt 61 along the central axis direction.
3 is formed, and a stopper rod 64 is screwed into this screw hole 63. The tip 64 of this stopper rod 64
a protrudes into the cylindrical case 59 and is connected to the combustion adjustment valve 16.
When the valve is opened by sliding in the direction of arrow C in FIG. . Therefore, by adjusting the rotation of the stopper rod 64, the maximum gap (indicated by ε in FIG. 4) between the tip of the combustion regulating valve 16 and the nozzle hole 52 is regulated. Note that this gap ε is preferably set to 31 or less. Note that a fixing nut 66 for preventing loosening is screwed onto the stopper rod 64.

As shown in FIGS. 1 and 4, the combustion regulating valve 16 is formed with a small diameter portion 70 having a predetermined length. On the other hand, a passage 71 is vertically formed in the cylinder block 12 and communicates with the outer peripheral gap of the small diameter portion 70, and a blow-by gas conduit 72 is connected to the upper end of the passage 71.

This conduit 72 is connected to the intake port of the engine (not shown), and passes through the outer peripheral gap of the combustion adjustment valve 16 to the small diameter portion 72.
The air-fuel mixture leaking to the side is sucked into the cylinder 1 again through the blow-by gas conduit 72.

In addition, the blow-by gas plug 7 is attached to the bend 30 cover 7.
3 is attached, and this plug 73 is also connected to the intake port of the engine (not shown). Then, the air-fuel mixture that has leaked into the airtight chamber 8 through the outer peripheral gap of the compression piston 13 is sucked into the cylinder 1 again through the plug 73. Note that a baffle plate 74 is provided below the plug 73.
is provided to prevent lubricating oil droplets from being sucked into the plug 73.

The compression device 4 of the pre-combustion chamber 27 is constructed as described above, and when the cam 14 rotates from the position shown by the chain line in FIG. is pressed by the cam 14, and the taperoid 5 and the compression piston 13 move forward in the direction of the arrow d against the compression spring 45. Further, when the cam 14 rotates from the position shown by the solid line in FIG. 1 to the position shown by the chain line, the compression piston 13 and the tappet 15 move back in the direction of the arrow a by the restoring force of the compression spring 45. Note that the compression ratio of the pre-combustion chamber 27 is higher than that of the main combustion chamber 22 when the compression ratio is
Set it so that it is larger than the compression ratio. The compression piston 13 continuously repeats such reciprocating motion, and since the compression piston 13 is driven by the cam 14 that is linked to the crankshaft, the operation of the compression piston 13 is extremely reliable. .

Next, the situation until the homogeneous air-fuel mixture introduced into the main combustion chamber 22 is ignited will be explained. First, when the compression piston 13 moves back and its tip end surface 13a comes to the position shown by the chain line in FIG. A part of the homogeneous air-fuel mixture introduced into the main combustion chamber 22 is sucked into the pre-combustion chamber 27 through the intake port 23 of the head bottom wall 3a and the intake passage 20. Thereafter, as the piston 9 rises, the compression piston 13 moves forward in the direction of arrow d in FIG.
7 and the intake passage 20 are interrupted by the compression piston 13. The homogeneous air-fuel mixture in the pre-combustion chamber 27 is independently compressed by the compression piston 13, and spontaneously ignites when the compression piston 13 moves forward to the position shown by the solid line in FIG. In addition, until combustion starts in the pre-combustion chamber 27,
Combustion adjustment valve 16 biased by nozzle hole 52 spring 53
Since the nozzle hole 52 is closed by the nozzle hole 52, the homogeneous air-fuel mixture during compression will not leak into the jet passage 21 from the nozzle hole 52.

Next, when combustion starts in the pre-combustion chamber 27, the pressure inside the pre-combustion chamber 27 rises rapidly, and this combustion pressure causes the combustion regulating valve 16 to slide against the spring 53 as shown in FIG. Nozzle hole 52 is opened. At this moment, the flame in the pre-combustion chamber 27 is ejected from the nozzle hole 52, and this flame propagates into the main combustion chamber 22 through the ejection passage 21 and the ejection port 24. ignite the homogeneous mixture.

When combustion starts in the main combustion chamber 22, the piston 9 descends due to the combustion pressure, the nozzle hole 52 is again closed by the combustion adjustment valve 16, and the compression piston 13 moves back in the direction of arrow a in FIG. The above-described operating cycle is then repeated continuously.

Note that by disposing electric heating plugs 77 and 78 in the intake passage 20 and the jetting passage 21 as shown in FIG. This improves the startability of the engine, especially in cold weather, and the flame propagating through the jet passage 21 is absorbed by the heating plug 78.
It is possible to prevent the flame from extinguishing during heating.

Next, a second embodiment of the present invention will be described based on FIGS. 6 to 9. In this second embodiment, as shown in FIG. 6, the compression piston I3 is driven by a circular positive cam 79, and as compared to the first embodiment, the compression spring 45 is not required. This compression device has advantages such as being able to drive the compression piston 13 at high speed, and can also be applied to high-speed rotation type engines. Specifically, as shown in FIG. 6, one disk 80 that slides on the positive cam 79 is attached to the compression piston 13 by four bolts 81 and nuts 82 on the upper, lower, left and right sides.
The other disc 83, which is fixed to the dish portion 28 of the cam 79 and slides on the positive cam 79, is attached to the other ends of the four bolts 81 with nuts 84. The outer circumferential surfaces of the four bolts 81 are in sliding contact with the outer circumferential surface of the camshaft 51, respectively, as shown in FIGS. 6 and 7, and are configured to act as a guide when the compression piston I3 reciprocates. has been done. Note that the threaded portion 81a of the bolt 81 is formed slightly eccentrically with respect to the bolt body 81b as shown in FIG. It is configured so that it can be easily brought into sliding contact with the outer circumferential surface of the shaft 51.

According to the positive cam 79 configured as described above, the relationship between the rotation angle of the camshaft 51 and the stroke of the compression piston 13 is represented by the curve shown in FIG.
It is not affected at all even if the number of revolutions of 1 becomes considerably high. Therefore, the compression device according to the present invention can be applied to high-speed rotation type engines as well.

According to experiments conducted by the present inventors, the camshaft 51
The compression piston 13 rotates from 60° to 90°.
The most stable operation results were obtained when the motor was allowed to move forward by 20 to 40 am.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways.

For example, in the above embodiments, the present invention was applied to a two-stroke gasoline engine, but it goes without saying that it is equally applicable to a four-stroke gasoline engine.

As mentioned above, the present invention is provided with a camshaft that interlocks with the crankshaft, and the compression piston is driven by the cam attached to this camshaft, so there is no delay in the operation of the pressure ta piston, and this type of This enables stable operation of the engine.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and include FIGS.
Fig. 5 shows the first embodiment, Fig. 1 is a longitudinal sectional view of the cylinder head portion of the engine, Fig. 2 is a longitudinal sectional view of the compression piston, Fig. 3 is a plan view of the cam and tappet, and Fig. 4. 5 is a vertical sectional view showing the combustion regulating valve and its surroundings, and FIG. 5 is an enlarged sectional view of the tip portion of the combustion regulating valve. Also, Figures 6 to 9
The drawings show the second embodiment, in which Fig. 6 is a side view of the positive cam and its surroundings, Fig. 7 is a right side view of Fig. 6, and Fig. 8 is a side view of the bolt. FIG. 9 is a curve diagram showing the relationship between the rotation angle of the camshaft and the stroke of the compression piston. ■・・・Cylinder, 3・・・Head, 1
2...Cylinder block, 13...Compression piston, 14...Cam, 15...
Tabeno L, 16... Combustion adjustment valve, 18...
...Cylinder hole, 19...Valve hole, 20...
...Intake passage, 21...Ejection passage, 22
...Main combustion chamber, 23...Intake port, 2
4... Jet nozzle, 27... Pre-combustion chamber,
51...Camshaft, 52...Nozzle hole,
79... Fixed cam. Figure 3 Figure 5 Figure 9 Rotation angle of cam fr, 51

Claims (1)

[Claims] (11) A pre-combustion chamber communicating with the main combustion chamber is provided, and the homogeneous ?1 gas which is sucked into the main combustion chamber and further flows into the pre-combustion chamber is disposed in the pre-combustion chamber. independently compressed by a compression piston and combusted therein, and the combustion pressure causes the combustion gas in the pre-combustion chamber to be injected into the main combustion chamber;
The internal combustion engine is configured to combust a homogeneous air-fuel mixture within the main combustion chamber, characterized in that a camshaft is provided that interlocks with the crankshaft of the internal combustion engine, and a cam that drives the compression piston is attached to the camshaft. A compression device for the pre-combustion chamber. (2) The pre-combustion chamber compression device according to claim 1, wherein the two cams are positive cams.