JPS62332B2 - - Google Patents

Description

Detailed Description of the Invention The present invention includes a main combustion chamber and a sub-combustion chamber to which an air-fuel mixture is supplied, and injects combustion flame generated in the sub-combustion chamber into the main combustion chamber through a torch nozzle. This invention relates to an improvement of a torch-ignited gasoline internal combustion engine that ignites and burns the air-fuel mixture in a combustion chamber.

First, the applicant proposed a torch-ignited gasoline internal combustion engine with a special structure that reduces harmful components such as CO, HC, and NOx in exhaust gas as much as possible, and significantly improves fuel consumption ( Japanese Patent Application Publication 1973-
(Refer to Publication No. 129208 and Japanese Patent Application Laid-open No. 54-50712)
However, recently there has been a demand for the development of high-performance gasoline internal combustion engines that not only reduce the generation of harmful components but also improve the fuel consumption rate and the engine's original output performance.

By the way, it is generally known that increasing the compression ratio of a gasoline internal combustion engine is effective as one of the technical means to increase thermal efficiency and improve fuel consumption and output. The occurrence of (abnormal combustion) becomes more pronounced, which actually leads to a decrease in output, and there is a limit to increasing the compression ratio.

It is generally said that the cause of knocking is due to the very rapid combustion of the final combustion part, that is, the end gas due to flame propagation of the air-fuel mixture.Means for suppressing this knocking include, for example, changing the temperature of the combustion gas, It is known to reduce the pressure, promote cooling of the combustion chamber walls, especially the end gas section, increase the flame velocity to reduce the combustion velocity, shorten the distance of flame propagation, etc. It is also known that the torch-ignited gasoline internal combustion engine has relatively excellent anti-knock properties.

Therefore, the present invention takes advantage of the above-mentioned characteristics of the torch-ignited gasoline internal combustion engine and adds structural improvements to them to suppress knocking, increase the compression ratio, reduce the generation of harmful components such as HC and CO, and reduce fuel consumption. The main purpose of this invention is to provide a high-performance torch-ignited gasoline internal combustion engine that is designed to significantly improve fuel efficiency and output performance.

Another object of the present invention is to provide a high-performance torch-ignited gasoline internal combustion engine that reduces combustion noise and enables quiet, nimble, and smooth operation.

To achieve the above object, according to the present invention, the upper surface of the piston has a recess having an oval cross section in the center and a flat portion around the recess, and a piston having an oval cross section facing the recess. a main combustion chamber consisting of a lower surface of a cylinder head having a recessed part and a flat part facing parallel to said flat part, and forming a squish area around the periphery; a sub-combustion chamber; a main intake valve port and an exhaust valve port that are opened in the head-side recess along the longitudinal direction thereof; a main intake valve and an exhaust valve that open and close the main intake valve port and the exhaust valve port, respectively; a main torch nozzle that is bored in the partition wall and has one end communicated with the bottom of the auxiliary combustion chamber and the other end communicated with the main combustion chamber; The combustion engine is characterized by comprising: an auxiliary nozzle that opens into the combustion area; and a spark plug that is attached to the cylinder head and has an electrode facing the auxiliary combustion chamber.

Hereinafter, a first embodiment of the present invention will be explained with reference to FIGS.
and a cylinder head 2 which is polymerized and bonded thereon via a gasket 3. A piston 5 is slidably fitted into a cylinder 4 formed in the cylinder block 1. On the upper surface of the piston 5, a piston-side recess 271 having an oval cross section and an arcuate longitudinal section is formed in the center thereof, and a flat portion ₂₇₂ around the piston side recess 271, while a flat portion ₂₇₂ is formed on the lower surface of the cylinder head 2. A head side recess ₆₁ having an oval cross section and an arcuate longitudinal section is formed facing the piston side recess ₂₇₁ , and _{a flat part 62 facing} the flat part 272 is formed. , recessed portion 27 ₁ and flat portion 27
A main combustion chamber M is formed by the concave portion ₆₁ and the flat portion _{62 of the cylinder head 2 and the cylinder head 2 ,} and when the piston 5 is at or near top dead center as shown in FIG. ₁ and 27 ₁ form the main body portion of the main combustion chamber M, which is approximately oval in cross section and spindle-shaped in longitudinal section, and the flat portions 6 ₂ and 27 ₂ that face each other form a squeezing area 29. .

Further, an auxiliary combustion chamber A is formed above one side of the cylinder head 2 across a partition wall.

A main intake valve port 7 is opened on one side of the recess ₆₁ forming the main combustion chamber M, and a main intake port 8 formed in the cylinder head 2 is communicated with the main intake valve port 7. The main intake port 8 is the main carburetor 9
It is connected to the main intake system. The main carburetor 9 is adjusted to produce an air-fuel mixture with a relatively lean air-fuel ratio.

The main intake valve port 7 is opened and closed by a main intake valve 10 that is slidably provided in the cylinder head 2 via a valve guide 11. When the valve is opened, a relatively lean air-fuel mixture generated by the main carburetor 9 is sucked into the main combustion chamber M through the main intake system.

As shown in FIG. 2, an exhaust valve port 12 is opened in the main combustion chamber M in parallel with the main intake valve port 7, and this exhaust valve port 12 is communicated with an exhaust port 13 formed in the cylinder head 2. ing. The exhaust valve port 12 is
The exhaust valve 14 is opened and closed by an exhaust valve 14. Like the main intake valve 10, this exhaust valve 14 is supported by the cylinder head 2 so as to be vertically slidable, and is opened and closed by a conventionally known valve operating mechanism.

The sub-combustion chamber A has a sub-intake valve port 15 on its upper surface.
is opened, and the sub-intake port 16 formed in the cylinder head 2 is communicated with the sub-intake valve port 15.
This auxiliary intake port 16 is communicated with a auxiliary intake system such as a auxiliary carburetor 17. The auxiliary carburetor 17 is adjusted to have a relatively rich air-fuel ratio mixture. A valve holder 18 is screwed onto the cylinder head 2 above the auxiliary combustion chamber A, and a communication passage 19 is formed in the valve holder 18 to communicate the auxiliary combustion chamber A and the auxiliary intake port 16. At the same time, a sub-intake valve 20 for opening and closing the sub-intake valve port 15 is supported to be slidable up and down,
This auxiliary intake valve 20 is opened and closed by a conventionally known valve mechanism, and when the valve is opened, the auxiliary carburetor 17 generates a relatively rich air-fuel mixture to the auxiliary intake port 1.
6 into the sub-combustion chamber A.

The auxiliary combustion chamber A is formed in a cylindrical shape with a spherical lower surface, and its longitudinal axis l ₁ -l ₁ is inclined from above to below in a direction intersecting the longitudinal axis LL of the cylinder 4. are doing.

A screw hole 22 for attaching a plug and a plug chamber 23 communicating with this hole 22 are formed below the auxiliary combustion chamber A, biased to one side thereof, and a spark plug P screwed into the screw hole 22 is formed. The electrode 24 is connected to the plug chamber 2.
3, and its plug chamber 23 is the auxiliary combustion chamber A.
It communicates with the bottom of the.

Main combustion chamber M and auxiliary combustion chamber A of cylinder head 2
The upper end of the partition wall separating the plug chamber 23 and
Two main torch nozzles 25 are bored through which the inner bottom of the auxiliary combustion chamber A communicates, and whose lower ends communicate with the main combustion chamber M, and the ends of the two main torch nozzles 25 on the main combustion chamber M side are connected to the main intake valve. 10 and the exhaust valve 14, and the two main torch nozzles 25 gradually approach each other as they move upward to form the secondary combustion chamber A.
A side end portion is opened spanning the sub-combustion chamber A and the plug chamber 23. Vertical axis of main torch nozzle 25
l ₂ -l ₂ is oriented above the longitudinal axis l ₃ -l ₃ of the spark plug P. The electrode 24 of the spark plug P is located outside the projected area of the opening end of the main torch nozzle 25 on the auxiliary combustion chamber A side. Main torch nozzle 25
consists of a straight part 25a on the plug chamber 23 side and a tapered part 25b that widens toward the main combustion chamber M side, and the straight part 25a and the tapered part 2
The boundary part 25c with 5b is biased towards the auxiliary combustion chamber A side.

One sub nozzle 26 is branched from each of the two main torch nozzles 25, and the lower ends of the sub nozzles 26 are connected to the torch area 2.
It opens at 9.

The sub nozzles 26 are formed to have a smaller diameter than the main torch nozzle 25, and the branching portions of these sub nozzles 26 are as follows:
Boundary portion 25 between the straight portion 25a and the tapered portion 25b
It is near c.

Next, to explain the operation of the first embodiment of the present invention shown in FIGS. A relatively lean mixture is sucked into the auxiliary combustion chamber A, and a relatively rich mixture is sucked into the auxiliary carburetor 17. Then, near the end of the compression stroke of the engine, the ignition plug P ignites the rich mixture in the sub-combustion chamber A, and the combustion flame generated thereby passes through the torch nozzle 25 and reaches the center of the main combustion chamber M. is ejected to ignite and burn the lean mixture in the main combustion chamber M. By the way, the combustion flame passing through the main torch nozzle 25 is injected into the main combustion chamber M, and at this time, the ejector effect of the combustion flame lowers the pressure in the sub nozzle 26, and in addition, the mixture in the main combustion chamber M is reduced. Due to the pressure increase in the chamber M caused by the combustion of air, the compressed unburned mixture in the squish area 29 can be sucked and recirculated into the main torch nozzle 25. By pressurizing the air-fuel mixture, the increase in pressure and temperature within the main combustion chamber M, which is a factor in suppressing the above-mentioned knocking, is suppressed, and as a result, the main combustion chamber M Even if the compression ratio is increased as much as possible, combustion pressure and temperature increases are suppressed due to the presence of the engine, and knocking is suppressed.

Furthermore, since the suction and reflux action re-combusts the unburned air-fuel mixture in the main combustion chamber M, it is possible to reduce the generation of combustible harmful components such as CO and HC.

Furthermore, by directing the opening end of the main torch nozzle 25 on the main combustion chamber M side toward the center of the chamber M, it is possible to shorten the flame propagation distance, which is another factor that suppresses knocking, and synergistically with the above-mentioned suction reflux effect, knocking is prevented. is suppressed.

Further, a rich air-fuel mixture flows into the auxiliary combustion chamber A during the intake stroke, and a lean air-fuel mixture flows into the main combustion chamber M during the compression stroke and is compressed, causing large turbulence in the air-fuel mixture. In this case, the plug chamber 23 is provided in the communication part of the main torch nozzle 25 on the side of the auxiliary combustion chamber A, and the electrode 24 of the spark plug P is arranged therein.
When the spark plug P ignites, the air-fuel mixture in the plug chamber 23 is ignited, and the combustion flame is divided into both the auxiliary combustion chamber A, which is highly turbulent, and the main torch nozzle 25, and the rich mixture in the auxiliary combustion chamber A is At the same time, combustion of the air-fuel mixture in the main combustion chamber M starts. Then, the accelerating torch flame of the main torch nozzle is ejected into the main combustion chamber M to accelerate combustion of the air-fuel mixture within the chamber M. At this time, the flame passing through the main torch nozzle 25 contains almost no unburned rich mixture, and is injected into the main combustion chamber M so as to follow the flame that has already propagated into the main combustion chamber M from the plug chamber 23. As a result, the combustion of the air-fuel mixture in the main combustion chamber M becomes smooth and continuous combustion without any turbulence, and the generation of combustion noise caused by combustion turbulence in the main combustion chamber M is significantly reduced. Therefore, the occurrence of knotting is also suppressed.

In addition, the volume of the main combustion part of the main combustion chamber M formed by the center of the upper surface of the piston 5 and the center of the upper surface of the cylinder head 2 is significantly reduced, and the flame from the two main torch nozzles 25 is
They are ejected downward from the main intake valve port 7 and the exhaust valve port 12 of the main combustion chamber M, respectively, so that the lean air-fuel mixture within the chamber M can be quickly combusted. The direction and number of the main combustion chamber M and the main torch nozzles 25 shorten the flame propagation distance to shorten the combustion time, which is a factor in suppressing knotting.
Due to the presence of other factors that inhibit knotking,
Knocking is suppressed synergistically by lowering the temperature and pressure of the air-fuel mixture.

In this first embodiment, the main torch nozzle 25
The projected surface of the opening end on the A side of the auxiliary combustion chamber is the spark plug P.
Since it is located away from the electrode 24, there is no fear that the flame kernel will be blown out by the pressurized lean mixture flowing from the main combustion chamber M into the main torch nozzle 25 during the compression stroke of the engine.

A second embodiment of the invention is shown in FIGS. 6 and 7. This second embodiment is slightly different from the first embodiment in the orientations of the two main torch nozzles 25. That is, the auxiliary combustion chamber A of the main torch nozzle 25
The side opening end faces the electrode 24 side of the spark plug P, and the electrode 24 is located within the projection plane of the opening end of the main torch nozzle 25 on the side of the sub-combustion chamber A.

In this second embodiment, during the upward compression stroke of the piston 5, a part of the pressurized lean mixture in the main combustion chamber M is injected into the auxiliary combustion chamber A through the main torch nozzle 25; The air is the electrode 2 of the spark plug P.
4 can be more or less cooled and also cleaned.

FIG. 8 shows a fourth embodiment of the invention. This fourth embodiment has a cylinder head 2 and a piston 5.
The main body of the compact main combustion chamber M is formed into a cocoon-shaped cross section with constrictions 28 and 28' in the center, and the main intake valve 10 is located in one half of the longitudinal direction. , and an exhaust valve 14 is arranged in the other half. The main torch nozzle 25 is composed of one main torch nozzle, and its opening end on the main combustion chamber M side is located at the longitudinal center of the main combustion chamber M having a cocoon-shaped cross section, and
0, the exhaust valve 14 is opened at the front of the middle part. Further, three sub nozzles 26 are branched from the main torch nozzle 25, and these are opened near the periphery of the main combustion chamber M.

FIG. 9 shows a fourth embodiment of the invention. This fourth embodiment differs from the third embodiment in that the number and orientation of the main torch nozzles 25 and sub nozzles 26 are slightly changed, and the two main torch nozzles 2
5 opens on both longitudinal sides of the main combustion chamber M, which has a cocoon-shaped cross section, directly below the main intake valve 10 and the exhaust valve 14, and one sub nozzle 26 is branched from each main torch nozzle 25, They are opened at the periphery of the main combustion chamber M.

In the above embodiment, the case where a lean mixture is supplied to the main combustion chamber M is explained, but the main combustion chamber M is supplied with an air-fuel mixture having an air-fuel ratio similar to that of the mixture supplied to a normal gasoline engine. may also be supplied.

As is clear from the above embodiments, according to the present invention, the main combustion chamber and the auxiliary combustion chamber are communicated with each other through the main torch nozzle, and a recess formed in the center portion on the piston side having a substantially oval cross section and a recess formed in the recess are provided. A corresponding recess formed in the center of the cylinder head side, which also has a substantially oval cross section, constitutes the main part of the main combustion chamber, making the main combustion part of the main combustion chamber extremely compact. Since the main intake valve and exhaust valve are arranged along the long axis of the main combustion chamber, which has an oval cross section, it is possible to satisfy the knocking suppression factors of shortening the combustion time and shortening the flame propagation distance. It is possible to further increase the output power and fuel consumption rate.

Furthermore, according to the present invention, the auxiliary nozzle is branched from the main torch nozzle that communicates the main combustion chamber and the auxiliary combustion chamber, and this auxiliary nozzle is communicated with the squish area around the main combustion chamber, so that the rich mixture in the auxiliary combustion chamber is The combustion flame obtained by ignition is caused by the pressure drop in the auxiliary nozzle due to the ejector effect and the compression of the unburned mixture in the squishing area, which causes the unburnt mixture in the main combustion chamber to be strongly sucked and recirculated through the auxiliary nozzle into the main torch nozzle. This strong suction reflux effect not only shortens combustion time and flame propagation distance, but also reduces the pressure and temperature inside the main combustion chamber, which more effectively suppresses knotting and improves compression. This makes it possible to increase the ratio and significantly improve output performance.

[Brief explanation of the drawing]

1 to 5 show a first embodiment of the present invention.
The figure is a longitudinal sectional view of the engine head equipped with the device of the present invention, Figure 2 is a bottom view of the combustion chamber of the cylinder head, and Figure 3 is a bottom view of the combustion chamber of the cylinder head.
The figures are a partial sectional view taken along the lines of FIG. 1, FIG. 4 is a side sectional view of the piston, FIG. 5 is a plan view of the piston, FIGS. is the same longitudinal cross-sectional view as Figure 1, and Figure 7 is the same as Figure 6.
A line sectional view, FIG. 8 shows a third embodiment of the present invention,
FIG. 9 shows a fourth embodiment of the present invention, and is a bottom view of the combustion chamber of the cylinder head. A... Sub-combustion chamber, M... Main combustion chamber, P... Spark plug, 2... Cylinder head, 5... Piston, 6 ₁ , 27 ₁ ... Recessed portion, 6 ₂ , 27 ₂ ... Flat portion, 7... Main intake valve port, 12... Exhaust valve port, 1
0...Main intake valve, 14...Exhaust valve, 24...Electrode, 25...Main torch nozzle, 25b...Tapered portion, 26...Subnozzle.

Claims (1)

[Scope of Claims] 1. The upper surface of the piston 5, which has a concave portion ₂₇₁ having an oval cross section in the center and _a flat portion ₂₇₂ around the concave portion; A main combustion chamber M is formed of a lower surface of the cylinder head 2 having a concave portion ₆₁ and a flat portion ₆₂ facing parallel to the flat portion ₂₇₂ , and has a skid area around the main combustion chamber M; A sub-combustion chamber A is formed between the main combustion chamber M and a partition wall; a main intake valve port 7 and an exhaust valve port ₁₂ that are opened in the head-side recess 61 along the longitudinal direction thereof;
and; a main intake valve 10 and an exhaust valve 14 that open and close the main intake valve port 7 and the exhaust valve port 12, respectively.
a main torch nozzle 25 bored in the partition wall and having one end communicated with the bottom of the auxiliary combustion chamber A and the other end communicating with the main combustion chamber M; branched from the main torch nozzle 25 and connected to the main combustion chamber A torch-ignited gasoline internal combustion engine characterized by comprising: an auxiliary nozzle 26 that opens into the combustion chamber M; and a spark plug P that is attached to the cylinder head 2 and has an electrode 24 facing the auxiliary combustion chamber A. institution. 2. In the torch-ignited gasoline internal combustion engine according to claim 1, the main torch nozzle 25 has a tapered portion 25b that widens toward the main combustion chamber M, and the auxiliary nozzle 26
A torch-ignited gasoline internal combustion engine in which the torch nozzle 25 is formed to have a smaller diameter than the main torch nozzle 25, and is branched at a substantially right angle from the axial direction of the main torch nozzle 25 at a position closer to the auxiliary combustion chamber A than the axial midpoint of the main torch nozzle 25. 3. In the torch-ignited gasoline internal combustion engine according to claim 1 or 2, the main combustion chamber M and the auxiliary combustion chamber A are connected to one main torch nozzle 2.
5, the opening end of the main torch nozzle 25 on the main combustion chamber M side is directed toward the center of the chamber M, and a plurality of sub nozzles 26 are branched radially from the main torch nozzle 25. Torch-ignited gasoline internal combustion engine. 4. In the torch-ignited gasoline internal combustion engine according to claim 1 or 2, the main torch nozzles 25 that communicate the main combustion chamber M and the auxiliary combustion chamber A are composed of a plurality of main torch nozzles 25. One end is connected to the auxiliary combustion chamber A, and one of the other ends is directed below the main intake valve 10, and the other end is directed below the exhaust valve 14. A torch-ignited gasoline internal combustion engine in which one sub-nozzle 26 is branched from a main torch nozzle 25.