Search

CN-121993283-A - Two-stroke engine

CN121993283ACN 121993283 ACN121993283 ACN 121993283ACN-121993283-A

Abstract

The invention is a divisional application with the application number of 202510973180. X. The invention discloses a two-stroke engine, and belongs to the technical field of engines. The two-stroke engine comprises a cylinder body and a piston, wherein an air inlet, an air outlet and a scavenging channel are formed in the cylinder body, a pair of first scavenging ports, a pair of second scavenging ports and a pair of third scavenging ports are formed in the wall of a combustion chamber, and the blowing elevation angles of the first scavenging ports, the second scavenging ports and the third scavenging ports are sequentially reduced and are used for enabling scavenging gas generated by the scavenging ports opened later to exert gas pressure deviating from the air outlet on scavenging gas generated by the scavenging ports opened earlier. According to the invention, the air blowing elevation gradient change of the three pairs of scavenging ports is utilized, the scavenging air flow with smaller elevation angle is utilized step by step to stabilize the combustible mixed gas, the formation of cyclone and the mixing with waste gas are prevented, the effective separation of the scavenging gas and the combustion waste gas is realized, the fuel utilization rate of the two-stroke engine is improved, the exhaust emission is improved, and the effects of energy conservation and emission reduction are achieved.

Inventors

  • WANG BOXIANG

Assignees

  • 常州共立新能源科技有限公司

Dates

Publication Date
20260508
Application Date
20250715

Claims (10)

  1. 1. Two-stroke engine, including cylinder body (1) and can be in the reciprocating motion's of the combustion chamber (1-1) of cylinder body (1) piston (2), cylinder body (1) is last have air inlet (5) and gas vent (6) that are linked together with combustion chamber (1-1) respectively, the communication port of air inlet (5) and combustion chamber (1-1) is less than the communication port of gas vent (6) and combustion chamber (1-1), still have scavenging channel (7) of intercommunication combustion chamber (1-1) and engine crankcase on cylinder body (1), its characterized in that: A pair of first scavenging ports (7 a), a pair of second scavenging ports (7 b) and a pair of third scavenging ports (7 c) are sequentially and oppositely arranged on the hole wall of the combustion chamber (1-1) by taking the exhaust center surface (P) of the exhaust port (6) as the center, the first scavenging ports (7 a), the second scavenging ports (7 b) and the third scavenging ports (7 c) are communicated with corresponding scavenging channels (7), and the scavenging directions (S) of the first scavenging ports, the second scavenging ports and the third scavenging ports are inclined to one side deviating from the exhaust port (6); The position of the first scavenging port (7 a) is far away from the exhaust port (6), the position of the third scavenging port (7 c) is close to the exhaust port (6), and the blowing elevation angles of the first scavenging port (7 a), the second scavenging port (7 b) and the third scavenging port (7 c) are sequentially reduced, so that scavenging gas generated by the scavenging port opened later exerts gas pressure deviating from the exhaust port (6) on scavenging gas generated by the scavenging port opened earlier.
  2. 2. The two-stroke engine according to claim 1, wherein the upper edge heights of the first scavenging port (7 a), the second scavenging port (7 b) and the third scavenging port (7 c) are sequentially lowered to sequentially open the first scavenging port (7 a), the second scavenging port (7 b) and the third scavenging port (7 c) during the downward movement of the piston (2) for driving and discharging the combustion exhaust gas toward the exhaust port (6) by the scavenging gas from far to near.
  3. 3. The two-stroke engine according to claim 2, wherein the scavenging gas of each pair of the first scavenging port (7 a), the second scavenging port (7 b) and the third scavenging port (7 c) meet at the exhaust center plane (P) of the exhaust port (6) such that the meet scavenging gas moves in a direction away from the exhaust port (6).
  4. 4. A two-stroke engine according to claim 3, characterized in that the scavenging direction (S) angle α 1 of the two first scavenging ports (7 a) is 120 ° -130 °, the scavenging direction (S) angle α 2 of the two second scavenging ports (7 b) is 120 ° -130 °, and the scavenging direction (S) angle α 3 of the two third scavenging ports (7 c) is 120 ° -130 °.
  5. 5. The two-stroke engine according to claim 4, wherein the included angle α 1 , the included angle α 2 and the included angle α 3 are the same.
  6. 6. The two-stroke engine according to claim 1, wherein the height of the upper edge of the exhaust port (6) on the wall of the combustion chamber (1-1) is larger than the height of the upper edge of the first scavenging port (7 a), for opening the exhaust port (6) prior to the first scavenging port (7 a) during the downward movement of the piston (2).
  7. 7. The two-stroke engine as claimed in claim 1, wherein the blowing elevation angle θ 1 of the first scavenging port (7 a) is 40 ° -50 °, the blowing elevation angle θ 2 of the second scavenging port (7 b) is 10 ° -20 °, and the blowing elevation angle θ 3 of the third scavenging port (7 c) is 0 ° -5 °.
  8. 8. The two-stroke engine as claimed in claim 7, wherein the blowing elevation angle θ 1 of the first scavenging port (7 a) is 45 °, the blowing elevation angle θ 2 of the second scavenging port (7 b) is 15 °, and the blowing elevation angle θ 3 of the third scavenging port (7 c) is 0 °.
  9. 9. The two-stroke engine as recited in claim 7, wherein the opening sizes of the first scavenging port (7 a), the second scavenging port (7 b) and the third scavenging port (7 c) are sequentially reduced so that the scavenging gas pressures generated by the first scavenging port (7 a), the second scavenging port (7 b) and the third scavenging port (7 c) are sequentially increased.
  10. 10. The two-stroke engine according to any one of claims 1 to 9, wherein the piston (2) is rotatably connected with one end of a connecting rod (3), the other end of the connecting rod (3) is rotatably connected with a crankshaft (4) arranged in a crankcase of the engine, and the crankshaft (4) is driven to rotate by the reciprocating motion of the piston (2) in the combustion chamber (1-1); When the piston (2) moves from the bottom dead center to the top dead center, the first scavenging port (7 a), the second scavenging port (7 b), the third scavenging port (7 c) and the exhaust port (6) are closed by the piston (2), the piston (2) passes through the air inlet (5) to open the air inlet (5), and the combustible mixture is sucked into the crankcase of the engine through the air inlet (5); When the piston (2) moves from the top dead center to the bottom dead center, the piston (2) closes the air inlet (5), sequentially opens the air outlet (6), the first scavenging port (7 a), the second scavenging port (7 b) and the third scavenging port (7 c), and the combustible mixture in the engine crankcase is blown into the combustion chamber (1-1) through the first scavenging port (7 a), the second scavenging port (7 b) and the third scavenging port (7 c), and simultaneously drives and discharges combustion waste gas in the combustion chamber (1-1) to the air outlet (6).

Description

Two-stroke engine The application relates to a split application of a two-stroke engine scavenging system and a two-stroke engine, which are disclosed in application No. 202510973180.X, application day 2025, 7, 15 and the application name. Technical Field The present invention relates to a two-stroke engine, and more particularly to a two-stroke engine with a scavenging system. Background The two-stroke engine is an engine for completing one working cycle in two strokes, has the advantages of simple structure, light volume, low production and maintenance cost and the like, and is commonly used in occasions with high power performance requirements, light weight and portability, such as handheld garden equipment, agricultural machinery, unmanned aerial vehicles and motorboats. The cylinder body of the common two-stroke engine is provided with an air inlet hole, an air outlet hole and an air vent hole, the three holes are respectively closed by a piston at a certain moment, the working cycle of the engine comprises a first stroke and a second stroke, in the first stroke, the piston moves upwards from a bottom dead center, after the three air holes are closed at the same time, the mixed gas entering the cylinder is compressed, and when the air inlet hole is exposed, the combustible mixed gas flows into a crankcase. In the second stroke, when the piston is compressed to the vicinity of the top dead center, the spark plug ignites the combustible mixed gas, the fuel gas expands to push the piston to move downwards to do work, at the moment, the air inlet is closed, the combustible mixed gas sealed in the crankcase is compressed, when the piston approaches to the bottom dead center, the air outlet is opened, the waste gas is flushed out, then the air exchanging hole is opened, the pre-pressed combustible mixed gas is flushed into the cylinder, and the waste gas is expelled, so that the air exchanging process is completed. As is apparent from the above structural principle of the two-stroke engine, the exhaust gas in the combustion chamber is mainly discharged by the scavenging action of the combustible mixture entering through the scavenging hole when the piston approaches the bottom dead center, and part of the combustible mixture is easily discharged along with the exhaust gas due to the interaction of the exhaust gas in the combustion chamber and the airflow of the combustible mixture, so that the fuel utilization rate is low and the exhaust gas pollution is serious, which is also the main cause of the wide scale of the two-stroke engine. At present, the scavenging technology is still a main technical means for reducing oil consumption and improving exhaust emission of a two-stroke engine, and a plurality of feasible technical schemes are also provided in the prior art. For example, kawasaki heavy industry Co., ltd.6.16 in 2011, a patent application having a patent publication number of CN102297012A, and a patent name of an "air-scavenged 2-stroke engine", which is provided with a first scavenge passage and a second scavenge passage between a combustion chamber and a crank chamber, wherein the first scavenge passage and the second scavenge passage have a first scavenging port and a second scavenging port at upper ends thereof lower than an upper end of an exhaust port, and the second scavenging port closer to the exhaust port has an upper end higher than an upper end of the first scavenging port, and air is ejected from the first scavenging port by the first scavenging port and then mixed gas is ejected from the first scavenging port during scavenging, and the air is closer to an exhaust port than the mixed gas, thereby preventing the mixed gas from being blown out from the exhaust port by the air introduced earlier. The design needs to add an air inlet, a related guide valve and an air passage on the cylinder body, has a complex structure and increases the manufacturing difficulty. As another example, japanese industrial personal computer corporation, at 3/18 2011, filed a patent application having a patent publication number CN102782280a, a patent name of a two-stroke engine and an engine tool including the engine, which includes a first scavenging port and a second scavenging port on an inner peripheral wall of a cylinder bore, and a first scavenging passage and a second scavenging passage connecting the first scavenging port and the second scavenging port to a crank chamber. The first and second scavenging passages are provided with outflow direction changing means for guiding in different directions an outflow of the air-fuel mixture flowing out into the cylinder bore from the vicinity of the top dead center of the first and second scavenging ports and an outflow of the air-fuel mixture flowing out into the cylinder bore from the vicinity of the bottom dead center of the first and second scavenging ports. The blowing angle of the second scavenging port has a larger inclination angle towards the bottom dead