CN201330656Y

CN201330656Y - Piston of natural gas engine

Info

Publication number: CN201330656Y
Application number: CNU2009200784225U
Authority: CN
Inventors: 万义军; 杨志勇; 张自力; 司鹏昆; 程辉; 陈孟强
Original assignee: DONGFENG NANCHONG AUTOMOBILE Co Ltd
Current assignee: Geely Sichuan Commercial Vehicle Co Ltd
Priority date: 2009-01-01
Filing date: 2009-01-01
Publication date: 2009-10-21
Anticipated expiration: 2019-01-01

Abstract

The utility model discloses a piston of a natural gas engine; a pit is arranged on the top of the piston, forming a combustion chamber; the pit (6) which forms the combustion chamber comprises a shelter-shaped arc necking (10) which is concave inwards after a section of straight wall, so that the combustion chamber has a larger capacity and contains more gas, the energy of combustion flames is enlarged and the temperature is raised, and mixed gas can be effectively organized and burned; the utility model has advantages of high thermal efficiency and low emission.

Description

The natural gas engine piston

Technical field

The utility model relates generally to a kind of natural gas engine, particularly the piston that cooperates with described cylinder.

Technical background

The outer mixed gas motor of known cylinder all be with fuel by air supply system by rock gas and air mixing, by gas-entered passageway and intake valve mixed gas is entered the firing chamber again, electricity consumption spark ignition mixed gas after fully mixing, therefore such firing chamber is the space between cylinder cap bottom and the piston head, for inflammable gas is mixed, often some special constructions are set on the surface of piston head, as establish some pits or rib leads to air-flow, in conjunction with the structure of gas-entered passageway, air-flow is formed roll or Cheng Xuanyou again; Yet some motor, as Chinese utility model patent, application number 200820063801.2, name is called " air supply system of gas as single fuel motor ", be the energy of making motor with pure natural gas, before entering cylinder, rock gas and air are fully mixed by a mixing arrangement, therefore when this piston ran to top dead center, the gap between at the bottom of upper top and the cylinder cap was very little, and upper top is except that leaving valve pit, be provided with pit at upper top and form the firing chamber, combination gas forms flame through igniting in the firing chamber, so the pit shape of end face formation firing chamber is extremely important on the piston, and the difference of combustion-chamber shape produces certain influence to combustion process.Common pit forms straight wall or outward-dipping inwards skew wall, owing to be subjected to the restriction of piston thickness, the pit depth that forms the firing chamber is all similar, and the shape of wall has a lot of designs, and therefore seeking a kind of design proposal preferably is that producer is pursued.

The model utility content

The purpose of this utility model is to provide a kind of piston that can overcome the known technology shortcoming, particularly form the structure of combustion recess, so that organize best eddy current to move, improve working medium and flow and velocity of propagation of flame, to improve the power that motor produces with squeezing stream.

For achieving the above object, scheme of the present utility model is: the pit of described formation firing chamber comprises the arc reducing of the blindage shape that a bit of straight wall is recessed inwards again.

She Ji advantage is that formed natural gas engine piston combustion bowl is because the blindage structure that the arc reducing forms has increased the neat pressure ratio in firing chamber like this, increased the speed of combustion flame, improve in-cylinder combustion, can effectively organize mixed gas to burn, thereby has a high thermal efficiency, the advantage of low emission, thus realized the purpose of this utility model.

Below in conjunction with diagram and embodiment's further instruction scheme of the present utility model.

Description of drawings

Fig. 1 is the sectional arrangement drawing of natural gas engine piston and cylinder head;

Fig. 2 is the stereogram of natural gas engine piston;

Fig. 3 is the A-A sectional view of piston among Fig. 2.

Embodiment

Cylinder cap 1 and a piston 2 that is in top dead center in the cylinder of comprising a natural gas engine as shown in Figure 1, cylinder cap is provided with gas-entered passageway and intake valve 3, spark plug 4, exhaust passage and exhaust valve 5, the upper-end surface of piston 2 is provided with the pit 6 that forms the firing chamber, a near coal-mine side of pit 6 accommodates intake valve 3, and the centre holds spark plug 4, exhaust valve 5.When diagram expression piston entered top dead center position, intake valve is opened can be to pit 6 air inlets that form the firing chamber, 4 igniting of air inlet end of a period spark plug, and fuel gas buring forms flame, thereby promotes descent of piston.

The expression that stereogram as shown in Figure 2 is concrete the upper top of piston form the structure of the pit 6 of firing chamber, and relate to the design of firing chamber optimum shape, the pit 6 that forms the firing chamber is circular at the sectional shape of piston upper top, present embodiment is not provided with and keeps away the valve pit, therefore the last end face of piston only has a circular port, and all the other structures and the known technology of piston are roughly the same.

Fig. 3 is the sectional view of firing chamber, neutral position at the piston upper top forms pit 6, there is a fillet 7 near coal-mine edge, the radius of fillet is 2-5 (mm), one end end face on piston of fillet, the other end extends in the hole, its end and a bit of straight wall 8 join, the other end of straight wall 8 joins by the arc reducing 10 of a roundlet angle 9 and a recessed inwards blindage shape, and the radius of fillet 9 is 2-5 (mm), and the radius of arc reducing is 6-12 (mm), the other end of arc reducing connects the end 11, hole, 11 is flat at the bottom of the described hole, and the end 11, hole forms the dark of pit to the piston upper top, and the described degree of depth is 12-28 (mm).

This programme piston combustion cell structure is owing to be different from known technology, quickened velocity of propagation of flame, allow fuel in atdc combustion, because high-temperature time is short, the amount that produces harmful gas reduces, and especially the amount of nitrogen compound reduces, and can reach Euro V emissions under the situation that adopts catalytic converter, Economy is improved simultaneously, therefore can obtain good economic benefit.

Claims

1, natural gas engine piston is provided with pit at the piston upper top and forms the firing chamber, and it is characterized in that: the pit (6) of described formation firing chamber comprises the arc reducing (10) of the blindage shape that a bit of straight wall is recessed inwards again.

2, natural gas engine piston according to claim 1, it is characterized in that: the neutral position at the piston upper top forms pit (6), there is a fillet (7) near coal-mine edge, one end end face on piston of fillet, the other end extends in the hole, its end and a bit of straight wall (8) join, the other end of straight wall joins by a little fillet (9) and the arc reducing (10) of a recessed inwards blindage shape, the other end of arc reducing connects the end (11), hole, and the end, hole forms the dark of pit to the piston upper top.

3, natural gas engine piston according to claim 2 is characterized in that: the radius of fillet (7) is 2-5 (mm).

4, natural gas engine piston according to claim 2 is characterized in that: the radius of fillet (9) is 2-5 (mm).

5, natural gas engine piston according to claim 2 is characterized in that: the radius of arc reducing (10) is 6-12 (mm).

6, natural gas engine piston according to claim 2 is characterized in that: the degree of depth in described hole is 12-28 (mm).