JPS58140418A - Engine with reserve chamber - Google Patents

Abstract

PURPOSE:To improve a combustion performance by producing a strong swirl through acceleration of an injection speed of a stored suction air and to improve a fuel cost efficinecy and emission properties, by a method wherein lift characteristics at an initial opening stage of an auxiliary valve for opening and closing a reserve chamber are set in a specified menner. CONSTITUTION:A reserve chamber 11 is formed in a cylinder head 3, and a part of a suction air in a combustion chamber 5 is reserved therein. At auxiliary valve 12 is attached to an opening 11a at the combustion chamber side of the reserve chamber 11. Lift characteristics against a crank angle at an initial opening stage of an auxiliary valve 12 are set such that it is more gentle than lift characteristics at a late opening stage. This enables acceleration of an injection speed of a reserved suction air through throttling of an opening area at an initial opening stage, and permits securing of a sufficient reserved suction air through reduction of a throttle resistance at a late opening stage. This causes the improvement of a combustion performance through production of a strong swirl, and allows the improvement of a fuel cost efficiency, emission properties and maneuverability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an engine with a storage chamber that stores a portion of intake air in a combustion chamber in the latter half of the compression stroke and blows it out at the beginning of the compression stroke of the next cycle.

Conventionally, the combustion performance is improved by generating a swirl in the intake air supplied into the combustion chamber to improve the intake flow velocity. As shown in Japanese Unexamined Patent Application Publication No. 1986, Google 2G θri No. 1, a storage chamber is formed in the cylinder head to store a part of the intake air in the combustion chamber, and an opening on the combustion chamber side of this storage chamber is A technology has been proposed in which an auxiliary valve is provided that opens at the beginning of the compression stroke and closes at the latter half of the compression stroke, and a part of the intake air that was stored in the latter half of the compression stroke of the previous cycle is ejected at the beginning of the compression stroke of the next cycle to generate a strong swirl. ing.

The above-mentioned proposed technology allows the swirl in the combustion chamber to remain during the combustion stroke to improve combustion performance (combustion speed), but the present invention improves the jetting speed of stored intake air from the storage chamber. The aim is to further improve combustion performance by generating a stronger swirl, thereby improving fuel economy, emissions, and drivability.

That is, the present invention sets the lift characteristic of the auxiliary valve that opens and closes the combustion chamber side opening of the storage chamber to the crank angle at the initial stage of valve opening to be gentler than the lift characteristic at the final stage of valve opening. The present invention provides an engine with a storage chamber that can secure a sufficient amount of stored intake air at the final stage of valve opening while increasing the ejection speed of stored intake air by narrowing the opening area.

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

In the engine shown in FIGS. 1 and 2, 1 is a cylinder block equipped with a piston 2, 6 is a cylinder head fixed on the cylinder block 1, and 4 is an intake port 6 that opens into a combustion chamber 5. 7 is the intake valve, 7 is the exhaust valve,
8 is a spark plug, 9 is a protrusion formed in the combustion chamber 5, and 10 is a cooling water passage.

On the other hand, 11 is a storage chamber formed in /Ricida Henode 3, 1
2 is an auxiliary valve that opens and closes the opening 11a of the storage chamber 11 to the combustion chamber 5 with a valve head 12a, and the stem 12b of the auxiliary valve 12 passes through the storage chamber 11 and is supported by the valve guide 16, and It penetrates through the intake valve 4 and is opened and closed by the valve operating mechanism 14 together with the intake valve 4.

In the valve mechanism 14, 15 is a camshaft, and 16 is an intake valve 4.
17 is a timing cam for the auxiliary valve 12; 18 is a rocker arm for the intake valve 4; 19 is a rocker arm for the auxiliary valve 12;
2 is a spring retainer, 22 and 23 are valve springs, and 24 is a valve guide for the intake valve 4.

Intake +F4 due to the shape of timing cam 16.17
The opening curve of the auxiliary valve 12 is as shown in FIG. The auxiliary valve 12 is set to be closed, and the lift characteristic of the auxiliary valve 12 relative to the crank angle is set to be gentler in the early stage A of valve opening than in the later stage B of valve opening. In other words, at the initial stage A of valve opening, the opening gradient is small, and the auxiliary valve 1
2 opens gradually, while the closing gradient is large at the final stage B of valve opening, and the auxiliary valve 12 closes quickly due to its large opening area.

To explain the operation of the above embodiment, during the intake stroke when the piston 2 descends, intake air is supplied into the combustion chamber 5 through the intake valve 4. At this time, the intake air is directed by the wall surface of the protrusion 9, flows around the spark plug 8, and generates a swirl.

Subsequently, during the compression stroke in which the piston 2 rises, the auxiliary valve 12 opens the opening 11a of the storage chamber 11 before and after the intake valve 4 closes, and from this storage chamber 11, at the end of the compression stroke of the previous cycle, the auxiliary valve 12 opens the opening 11a of the storage chamber 11. The air that has been stored at high pressure is blown out. The lift characteristic of the auxiliary valve 12 at the initial stage of opening is gentle and the auxiliary valve 12 opens gradually, so its opening area is narrowed to a small size, so its jet velocity is high and the swirl caused by the protrusion 9 is promoted. As a result, an even larger swirl is generated within the combustion chamber 5. This ejection of energy from the storage chamber 11 continues until the pressure in the storage chamber 11 and the pressure in the combustion chamber 5 match.

Furthermore, when piston 2 rises and the compression stroke progresses,
The pressure in the combustion chamber 5 becomes lower than the pressure in the storage chamber 11, and conversely, the intake air compressed in the combustion chamber 5 flows into the storage chamber 11, and a part of the intake air is compressed by the compression pressure when the auxiliary valve 12 closes. is stored. At this time, the lift characteristic (valve closing characteristic) of the auxiliary valve 12 relative to the crank angle in the latter half of the opening period is steep, and the throttling resistance due to the auxiliary valve 12 is small, allowing a necessary and sufficient amount of intake air to flow without being obstructed. is stored in the storage chamber 11.

Immediately after the auxiliary valve 12 closes, the compressed intake air in the combustion chamber 5 is ignited by the spark plug 8, and good combustion is performed while maintaining the swirl. Accordingly, a squish flow is generated in the intake air pushed up from below by the bottom surface of the protrusion 9.

The present invention is not limited to the structure of the above embodiment,
It includes various modifications. That is, in the embodiment described above, the swirl or squish flow generated by the protrusion 9 is further promoted by the jet flow from the storage chamber 11.
The swirl may be formed only by the ejected flow from 1, and in this case, the intake resistance due to the protrusion 9 is reduced.

As explained above, according to the present invention, the lift characteristic of the auxiliary valve that opens and closes the storage chamber with respect to the crank angle at the initial stage of valve opening is set to be gentler than the lift characteristic at the later stage of valve opening. By narrowing down the opening area, the ejection speed of the stored intake air can be reduced, and in the later stages of valve opening, the throttling resistance can be reduced to ensure a sufficient amount of stored intake air, resulting in a more powerful swirl. This improves combustion performance and improves fuel efficiency, emissions, and drivability.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a sectional view of the main parts of the engine, Fig. 2 is a schematic bottom view of the cylinder head, and Fig. 3 is a schematic bottom view of the cylinder head.
The figure is a curve diagram showing the lift characteristics of the auxiliary valve. 1...Cylinder lock, 3...Cylinder head, 4...1 Air valve, 5...Combustion chamber, 1
1... Storage chamber, 11a... Opening, 1
2... Auxiliary valve, 12a... Valve head, 12
k)... Stem, 14... Valve mechanism,
15...Camshaft, 17-= = Timing cam Fig. 2 Fig. 3 Crank angle

Claims (1)

[Claims] (1) An engine with a storage chamber that forms a storage chamber that stores a portion of the intake air in the combustion chamber, and is provided with an auxiliary valve that opens at the beginning of the compression stroke and closes at the end of the compression stroke at the combustion chamber side opening of the storage chamber. An engine with a storage chamber, characterized in that a lift characteristic of the auxiliary valve with respect to a crank angle at an early stage of opening the auxiliary valve is set to be gentler than a lift characteristic at a later stage of opening the auxiliary valve.