Low-Emission Cylinder with External Scavenging Duct

Abstract

The present utility model relates to the technical field of engines, in particular to a low-emission cylinder with an external scavenging duct, wherein cylinder side covers are mounted on two opposite side walls of a cylinder body, a top surface of the cylinder body is a top surface of the uppermost cooling fin and a bottom surface thereof is a mounting surface, an exhaust port is provided in an inner cylinder bore of the cylinder body, an exhaust outlet is provided on a side wall of the cylinder body corresponding to the exhaust port, scavenging ports are respectively provided on two side walls in the inner cylinder bore adjacent to the exhaust port, a scavenging bore is provided in the side wall opposite to the exhaust port in an axial direction, a scavenging duct inlet is provided on the mounting surface corresponding to the side wall of the scavenging bore, scavenging grooves are respectively provided outside the side walls corresponding to the scavenging ports, and scavenging duct is formed between the corresponding scavenging port, the scavenging groove, the scavenging bore, the scavenging duct inlet and the cylinder side cover. The advantages are as follows: the low-emission cylinder can not only ensure the power performance and economical efficiency of engines, has low emission values without needing a secondary purification treatment, but can also satisfy the requirements on the limit values of emission standard.

Claims

1. A low-emission cylinder with an external scavenging duct, comprising a cylinder body and cylinder side covers, the cylinder side covers being mounted on two opposite side walls of the cylinder body, the upper side of the cylinder body being provided with cooling fins, a top surface of the cylinder body being a top surface of the uppermost cooling fin and a bottom surface of the cylinder body being a mounting surface, an inner cylinder bore and a combustion chamber being provided inside the cylinder body, an exhaust port being provided in the inner cylinder bore, and an exhaust outlet being provided on a side wall of the cylinder body corresponding to the exhaust port, wherein scavenging ports are respectively provided on two side walls in the inner cylinder bore adjacent to the exhaust port, a scavenging bore is provided in a side wall opposite to the exhaust port in an axial direction, a scavenging duct inlet in communication with the scavenging bore is provided on the mounting surface corresponding to the side wall provided with the scavenging bore, scavenging grooves are respectively provided outside the side walls corresponding to the scavenging ports, one end of the scavenging groove is in communication with the scavenging bore and the other end of the scavenging groove is in communication with the scavenging port, and a scavenging duct is formed between the corresponding scavenging port, the scavenging groove, the scavenging bore, the scavenging duct inlet and the cylinder side cover.

2. The low-emission cylinder with an external scavenging duct according to claim 1, wherein the scavenging groove is arranged in a radial direction of the inner cylinder bore, and the scavenging groove and the scavenging bore are perpendicular to each other or form therebetween an included angle which is greater than 0 degrees and smaller than 90 degrees or which is greater than 90 degrees and smaller than 180 degrees.

3. The low-emission cylinder with an external scavenging duct according to claim 2, wherein the joint of the scavenging groove and the scavenging bore is of a circular arc transition.

4. The low-emission cylinder with an external scavenging duct according to claim 1, wherein the volume of the scavenging duct is not less than 30% of the maximum exhaust volume of the cylinder.

5. The low-emission cylinder with an external scavenging duct according to claim 1, wherein the ratio of the area of the scavenging duct inlet to the length of the scavenging duct is not greater than 0.13.

6. The low-emission cylinder with an external scavenging duct according to claim 1, wherein the cross-sectional area of the scavenging duct gradually decreases from the scavenging duct inlet to the scavenging port.

7. The low-emission cylinder with an external scavenging duct according to claim 1, wherein a protrusion is provided at the position of the cylinder side cover corresponding to the scavenging port, and the protrusion is inserted in the scavenging port.

8. The low-emission cylinder with an external scavenging duct according to claim 1, wherein upper and lower edges of the exhaust port are both of a circular arc surface, and the radius of curvature of the upper circular arc surface is less than the radius of curvature of the lower circular arc surface.

9. The low-emission cylinder with an external scavenging duct according to claim 1, wherein the cross-sectional area gradually increases from the exhaust port to the exhaust outlet.

10. The low-emission cylinder with an external scavenging duct according to any one of claims 1, wherein the combustion chamber is a semi-ellipsoidal chamber, and the ratio of the area of an inner surface to the volume of the combustion chamber is not greater than 6.2.

Description

DESCRIPTION OF THE DRAWINGS

[0025] The present utility model will be further explained below in conjunction with the accompanying drawings.

[0026] FIG. 1 is a dimensional structural schematic view of the present utility model.

[0027] FIG. 2 is an exploded structural schematic view of the present utility model.

[0028] FIG. 3 is a front structural schematic view of the present utility model.

[0029] FIG. 4 is a sectional structural schematic view of the present utility model.

[0030] FIG. 5 is a partial sectional structural schematic view of the present utility model.

[0031] FIG. 6 is a front structural schematic view of the combustion chamber of the present utility model.

[0032] FIG. 7 is a side structural schematic view of the combustion chamber of the present utility model.

[0033] FIG. 8 is a bottom structural schematic view of the combustion chamber of the present utility model.

PARTICULAR EMBODIMENTS

[0034] With reference to FIGS. 1-8, a low-emission cylinder with an external scavenging duct disclosed in the present utility model comprises a cylinder body 10 and cylinder side covers 11, wherein the overall shape of the cylinder body 10 is square with six faces in total, the cylinder body 10 and the cylinder side covers 11 are sealed by a gasket 12 therebetween, and in a general case, the cylinder side covers 11 and the gasket 12 are locked and attached to the cylinder body 10 via screws. The cylinder side covers 11 are mounted on two opposite side walls of the cylinder body 10, the upper side of the cylinder body 10 is provided with cooling fins 13, a top surface of the cylinder body 10 is a top surface of the uppermost cooling fin and a bottom surface thereof is a mounting surface 14, and generally, not less than 10 layers of cooling fins 13 are evenly distributed on the cylinder body 10, with the minimum thickness of a single cooling fin not exceeding 1.3 mm, and with different longitudinal and transverse cross-sectional shapes of the cooling fins 13. The cross sections in the gas inlet and outlet directions are of parallel lines, with the root being V-shaped and in a smooth transition; and the axial cross section is of a shape gradually reducing from outside to inside, with the root being V-shaped and in a smooth transition. Thus, some of heat generated when the engine works is discharged out of the engine body along with exhaust gas generated from combustion, the other part thereof exchanges heat by convection between the cooling fins and the outside air, the heat exchange amount from the cooling fins to the cooling air, except the related structural parameters of the cooling fins themselves, further depends on peripheral flow field distribution, and poor heat dissipation affects power performance and economical efficiency of engines. The cylinder has a large number of cooling fins, the effective heat dissipation area is large, the thickness of the cooling fins and shapes connected among various cooling fins are specially arranged, and the heat dissipation effect is very good.

[0035] An inner cylinder bore 15 and a combustion chamber 16 are arranged in the cylinder body 10, an exhaust port 17 is provided in the inner cylinder bore 15, an exhaust outlet 18 is provided on a side wall of the cylinder body 10 corresponding to the exhaust port 17, scavenging ports 19 are respectively provided on two side walls of the inner cylinder bore 15 adjacent to the exhaust port 17, a scavenging bore 20 is provided in the side wall opposite to the exhaust port 17 in an axial direction, a scavenging duct inlet 21 in communication with the scavenging bore 20 is provided on the mounting surface 14 corresponding to the side wall provided with the scavenging bore 20, scavenging grooves 22 are respectively provided outside the side walls corresponding to the scavenging ports 19, one end of the scavenging groove 22 is in communication with the scavenging bore 20 and the other end thereof is in communication with the scavenging port 19, and a scavenging duct 23 is formed between the corresponding scavenging port 19, the scavenging groove, the scavenging bore 20, the scavenging duct inlet 21 and the cylinder side cover 11. The scavenging groove is arranged in a radial direction of the inner cylinder bore 15, and the scavenging groove and the scavenging bore 20 are perpendicular to each other or form therebetween an included angle which is greater than 0 degrees and smaller than 90 degrees or which is greater than 90 degrees and smaller than 180 degrees. The joint of the scavenging groove and the scavenging bore 20 is of a circular arc transition, and such design enables air flow to flow more smoothly in the scavenging duct. The volume of the scavenging duct is not less than 30% of the maximum exhaust volume of the cylinder. The ratio of the area of the scavenging duct inlet to the length of the scavenging duct is not greater than 0.13. The cross-sectional area of the scavenging duct gradually decreases from the scavenging duct inlet to the scavenging port. A protrusion 22 is provided at the position of the cylinder side cover 11 corresponding to the scavenging port 19, and the protrusion 22 is inserted in the scavenging port 19.

[0036] As mentioned above, upper and lower edges of the exhaust port 17 are both of a circular arc surface, and the radius of curvature of the upper circular arc surface is less than the radius of curvature of the lower circular arc surface. The cross-sectional area gradually increases from the exhaust port 17 to the exhaust outlet 18. The exhaust outlet 18 is square, with upper and lower edges and four vertex angles being of a circular arc transition, and is formed by connecting four sections of gradient curved surfaces from the exhaust port 17 to the exhaust outlet 18, an upper curved surface gradually extends from inside to outside, a lower curved surface is of a Z shape and extends to the outside, the cross section of the exhaust port forms a trend of increase from inside to outside, with regard to upper and lower curved surfaces from the inner surface, a first section A is approximately parallel, a second section B forms a small included angle, a third section C forms a large included angle, and a fourth section D forms a relatively small included angle. The combustion chamber 16 is a semi-ellipsoidal chamber, and the ratio of the area of an inner surface to the volume of the combustion chamber 16 is not greater than 6.2.

[0037] As mentioned above, gas inlets 24 are arranged on the same side with air inlets 25, and are located on opposite side walls of the exhaust port, the air inlets 25 are square and are located on two sides above the gas inlets 24, the air inlets 25 are arranged to be two in number, and two air inlets 25 are communicated by a narrow strip-shaped groove 26 and are on the same mounting surface with the gas inlets 24.

[0038] In the working process of an engine equipped with the cylinder, a fuel gas mixture enters a crankcase through a gas inlet, air enters the crankcase through an air inlet, the concentrated gas mixture is diluted with part of the air to form a combustible gas mixture with a proper concentration, and some is stored in the scavenging duct. After the gas mixture having entered the combustion chamber in the last cycle is ignited and exploded to apply work, the air stored in the scavenging duct firstly enters the combustion chamber for scavenging, and then the gas mixture enters the combustion chamber through the scavenging duct for continuously scavenging. During exhausting, the air firstly entering the combustion chamber is spaced between the exhaust gas and the gas mixture, the exhausting is carried out in the order of exhaust gas, air and gas mixture, and the exhaust port is sealed at the proper time. Since the closed passage of the scavenging duct has a large volume, the area of the scavenging duct inlet is small, the amount of stored air is large, and a relatively thick spacer layer is formed in the combustion chamber, such that the amount of the gas mixture escaping during exhausting is less. Exhaust gas is directly discharged out of the engines during exhausting, and the emission value of such low-emission engine is generally about 40 g/kW.h and can satisfy the requirements of emission limit values.

[0039] The above-mentioned embodiments are merely preferred embodiments of the present utility model, and are not used to limit the scope of protection of the present utility model, and therefore equivalent changes made according to the structure, shape and principle of the present utility model shall be contained within the scope of protection of the present utility model.