CN110566343A

CN110566343A - Two-stroke engine

Info

Publication number: CN110566343A
Application number: CN201910739487.8A
Authority: CN
Inventors: 范宝伟; 张耀元; 王远光
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2019-08-12
Filing date: 2019-08-12
Publication date: 2019-12-13

Abstract

The invention provides a two-stroke engine, which comprises a cylinder body and a crank block mechanism; a compression chamber and a rotor cavity which are communicated are arranged in the cylinder body; the wall surface of the rotor cavity and the rotor form a plurality of combustion chambers, and the slider of the slider-crank mechanism moves in the compression chamber and ignites mixed gas in the combustion chambers; and an output shaft of the rotor is connected with a crank of the slider-crank mechanism through a transmission mechanism. The compression chamber is communicated with the rotor cavity through a reducer; and the reducer is provided with an air inlet channel, and the air inlet channel is provided with a one-way valve for preventing the backflow in the compression process. One end of a sliding block of the crank sliding block mechanism is in a reducing shape, and the reducing end of the sliding block is matched with the reducing pipe and used for completely compressing mixed gas in the compression chamber into the combustion chamber. The invention completely separates the air intake and the exhaust, reduces the scavenging process and avoids the charge loss caused by the escape of fresh mixed gas from the exhaust port in the air intake stroke.

Description

Two-stroke engine

Technical Field

The invention relates to the technical field of power mechanical systems, in particular to a two-stroke engine.

Background

The two-stroke engine has natural advantages compared with a four-stroke engine, namely the two-stroke engine does work once because the crankshaft rotates for one circle, and therefore the working capacity is strong. The advantages of a two-stroke engine are therefore high efficiency, simple construction and few parts. However, the scavenging of the conventional two-stroke engine is mainly performed, namely, compressed fresh air-fuel mixture is used for directly driving and extruding combusted waste gas, so that the scavenging time is short, the fresh charge and the combusted waste gas are mixed for a long time, the scavenging quality of the engine is low, the residual waste gas coefficient is large, and a large amount of fresh charge is lost. Therefore, the conventional two-stroke engine has a drawback that not only fuel economy is deteriorated but also the amount of harmful gas such as unburned HC is increased, and it is difficult to satisfy the increasingly strict exhaust emission regulations. The improvement and development of the prior art mostly focus on the optimization of the scavenging process, the power performance and the emission performance are improved to a certain extent, but the inherent defects of the scavenging process, namely the problems of incomplete exhaust escape of a fresh charge from an exhaust passage and long-term mixing of the fresh charge and combustion exhaust gas, cannot be fundamentally changed. In addition, the traditional two-stroke engine cannot achieve a high compression ratio for avoiding negative factors such as knocking and the like, and the two-stroke engine starts to exhaust at 65-75 degrees CA before the bottom dead center, so that the effective acting stroke is short. Therefore, there is a need to design a new combustion chamber and scavenging system to replace the scavenging system of a conventional two-stroke engine to improve the scavenging process and improve the overall performance of the engine.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the two-stroke engine which can completely separate air intake and exhaust, reduce the scavenging process, avoid charge loss caused by the escape of fresh mixed gas from an exhaust port in the air intake process and avoid the problem of reduced ventilation quality caused by the failure of completely exhausting combustion waste gas in the exhaust process. The invention also extends the intake time of the two-stroke engine and improves the charge coefficient.

The present invention achieves the above-described object by the following technical means.

A two-stroke engine comprises a cylinder body and a crank block mechanism; a compression chamber and a rotor cavity which are communicated are arranged in the cylinder body; the wall surface of the rotor cavity and the rotor form a plurality of combustion chambers, a slide block of the slider-crank mechanism moves in a compression chamber and is used for compressing mixed gas into any combustion chamber and igniting the mixed gas in the combustion chamber to enable the rotor to rotate; and an output shaft of the rotor is connected with a crank of the slider-crank mechanism through a transmission mechanism.

Further, the compression chamber is communicated with the rotor cavity through a reducer; and the reducer is provided with an air inlet channel, and the air inlet channel is provided with a one-way valve for preventing the backflow in the compression process.

Furthermore, one end of the sliding block of the crank sliding block mechanism is in a reducing shape, and the reducing end of the sliding block is matched with the reducing pipe and used for completely compressing the mixed gas in the compression chamber into the combustion chamber.

Further, an exhaust mechanism is mounted on the cylinder body and used for forcibly exhausting air.

further, the exhaust mechanism comprises an exhaust baffle and an elastic reset device, an exhaust passage communicated with any combustion chamber is arranged on the cylinder body, the exhaust baffle is arranged in the wall surface of the rotor cavity near the exhaust passage, and the elastic reset device is used for ensuring that one end of the exhaust baffle is tightly attached to the profile of the rotor.

Further, the transmission mechanism is a gear train.

Further, the gear train includes a first gear, a second gear, and an idler gear; the first gear is connected with a crank of the crank sliding block mechanism; the output shaft of the rotor is connected with a second gear, and the first gear and the second gear are respectively meshed with an idler wheel.

Further, the gear ratio of the first gear to the second gear is 1: 3; the wall surface of the rotor cavity and the rotor form 3 combustion chambers; through the gear train for realize that the rotor rotates 1 circle, slider reciprocating motion 3 times in the compression chamber of slider-crank mechanism.

The invention has the beneficial effects that:

1. The two-stroke engine of the invention completely separates the air intake from the air exhaust, avoids the condition of mixing the fresh mixed gas and the combustion waste gas, and solves the problems of the escape of the fresh mixed gas from the exhaust passage in the air intake stroke and the incomplete air exhaust in the exhaust stroke.

2. The two-stroke engine has no scavenging process, reduces the discharge amount of unburned HC, improves the charge coefficient, avoids energy consumption in the scavenging process and improves the fuel utilization rate.

3. The two-stroke engine has the advantages that the compression chamber and the combustion chamber are designed separately, the compression chamber is not required to be considered when the volume of the combustion chamber is designed, so that the volume of the combustion chamber can be further reduced, the flame propagation distance of the ignition plug after ignition is shortened by the novel combustion chamber, the detonation phenomenon is reduced, and the compression ratio of the engine is favorably improved. Meanwhile, the effective working stroke of the engine is prolonged through the matching of the combustion chamber and the exhaust passage. 4. According to the two-stroke engine, the one-way valve is arranged in the air inlet channel, so that the escape of fresh air through the air inlet channel in a compression stroke is reduced, and the charge coefficient of the engine is increased.

5. The two-stroke engine provided by the invention adopts the exhaust baffle to assist in exhaust, and is beneficial to enhancing the exhaust effect of the exhaust passage.

Drawings

FIG. 1 is a block diagram of a two-stroke engine according to the present invention.

Fig. 2 is a schematic view of a two-stroke engine according to the invention at the beginning of the intake stroke.

Fig. 3 is a schematic view of a two-stroke engine according to the invention at the start of the compression stroke.

Fig. 4 is a schematic view of a two-stroke engine according to the invention at the start of the combustion stroke.

FIG. 5 is a schematic diagram of a two-stroke engine of the present invention at the beginning of the exhaust stroke

FIG. 6 is a schematic diagram of the two-stroke engine of the present invention at the beginning of the next cycle.

In the figure:

1-a cylinder body; 2-a slider-crank mechanism; 3-a first gear; 4-a second gear; 5-an idler wheel; 6-an exhaust passage; 7-an air inlet channel and 8-a one-way valve; 9-a compression chamber; 10-rotor cavity; 11-a rotor; 12-a slide block; 13-a spark plug; 14-an exhaust baffle; 15-a first combustion chamber; 16-a second combustion chamber; 17-third combustion chamber.

Detailed Description

The invention will be further described with reference to the following figures and specific examples, but the scope of the invention is not limited thereto.

as shown in fig. 1 and 2, the two-stroke engine according to the present invention includes a cylinder block 1 and a crank block mechanism 2; a compression chamber 9 and a rotor cavity 10 which are communicated are arranged in the cylinder body 1; 3 combustion chambers are formed between the wall surface of the rotor cavity 10 and the rotor 11, and the slider 12 of the slider-crank mechanism 2 moves in the compression chamber 9 and is used for compressing the mixed gas into any combustion chamber; a spark plug 13 is arranged on the cylinder body 1, and mixed gas in a combustion chamber is ignited through the spark plug 13 for rotating the rotor 11; the output shaft of the rotor 11 is connected with the crank of the crank block mechanism 2 through a transmission mechanism. The compression chamber 9 is communicated with the rotor cavity 10 through a reducer; and an air inlet channel 7 is arranged on the reducing pipe, and a check valve 8 is arranged on the air inlet channel 7 and used for preventing the backflow in the compression process. One end of a slide block 12 of the crank slide block mechanism 2 is in a tapered shape, and the tapered end of the slide block 12 is matched with the reducing pipe and used for completely compressing the mixed gas in the compression chamber 9 into the combustion chamber. The exhaust passage 6 communicated with any combustion chamber is arranged on the cylinder body 1, so that air intake and exhaust are completely separated, the scavenging process is reduced, the charge loss caused by the escape of fresh mixed gas from an exhaust port in the air intake process is avoided, and the problem of the reduction of the air exchange quality caused by the fact that the burnt waste gas cannot be exhausted in the exhaust process is also avoided.

An exhaust mechanism is arranged on the cylinder body 1 and used for forcibly exhausting. The exhaust mechanism comprises an exhaust baffle 14 and an elastic resetting device, the exhaust baffle 14 is arranged in the wall surface of the rotor cavity 10 near the exhaust passage 6, and the elastic resetting device is used for ensuring that one end of the exhaust baffle 14 is tightly attached to the profile of the rotor 11.

the transmission mechanism is a gear train. The gear train comprises a first gear 3, a second gear 4 and an idler gear 5; the first gear 3 is connected with a crank of the crank slide block mechanism 2; the output shaft of the rotor 11 is connected with the second gear 4, and the first gear 3 and the second gear 4 are respectively meshed with the idle gear 5. The gear ratio of the first gear 3 to the second gear 4 is 1: 3; through a gear train, for realizing that the rotor 11 rotates for 1 circle, the slider 12 of the slider-crank mechanism 2 reciprocates 3 times in the compression chamber 9. Through the connection mode, the transmission mechanism realizes that the rotor 11 rotates for one circle, namely 360 degrees, and the crank is driven by the gear train to rotate for three circles, namely 1080 degrees, namely three cycles of reciprocating motion of the slide block 12, and the first combustion chamber 15, the second combustion chamber 16 and the third combustion chamber 17 respectively do work once in the period.

As shown in fig. 2, 3, 4, 5 and 6, the two-stroke engine of the present invention has a working stroke divided into 4 parts: an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke.

In fig. 2, point a is located at the rotor 10 tip; point B is the position of the reducer; point D is the position of the spark plug 13, i.e., point B is rotated 120 degrees counterclockwise; point E is the position of the exhaust port, point C is the position of point D on the wall surface of the rotor cavity 10 rotated clockwise by 60 degrees;

An air inlet stroke: starting from point B (fig. 2), point a is rotated 60 ° counterclockwise to point C (fig. 3). The slider-crank mechanism 2 drives the slider 12 to move upwards, the air inlet channel 7 starts to intake air, and fresh mixed air passes through the one-way valve 8 and then simultaneously enters the compression chamber 9 and the first combustion chamber 15.

Compression stroke: starting from point C (fig. 3), point a is rotated 60 ° counterclockwise to point D (fig. 4). The slider-crank mechanism 2 drives the slider 12 downward to start compressing the mixture in the compression chamber 9 and the first combustion chamber 15. Because of the presence of the non-return valve 8, the mixture cannot escape from the inlet channel 7 and the slider 12 presses all the mixture into the first combustion chamber 15.

A combustion stroke: when point a reaches point D (see fig. 4), ignition of the spark plug 13 is started. Starting from point D, point a is rotated 180 ° counterclockwise to point E (fig. 5), during which time the gases in the first combustion chamber 15 continue to burn and produce work.

An exhaust stroke: when point a rotates counterclockwise (as shown in fig. 6) from point E, the first combustion chamber 15 communicates with the exhaust passage 6 to start exhaust, and the exhaust damper 14 assists the exhaust passage 6 to completely exhaust the in-cylinder combustion exhaust gas through the exhaust passage 6.

When point a reaches point B again (fig. 6), the intake of air from the front section of the first combustion chamber 15 starts, and the next working cycle is started.

The three combustion chambers of the first combustion chamber 15, the second combustion chamber 16 and the third combustion chamber 17 work alternately, and the continuous and stable running of the engine is ensured.

The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A two-stroke engine is characterized by comprising a cylinder body (1) and a crank block mechanism (2); a compression chamber (9) and a rotor cavity (10) which are communicated are arranged in the cylinder body (1); the wall surface of the rotor cavity (10) and the rotor (11) form a plurality of combustion chambers, and a slider (12) of the slider-crank mechanism (2) moves in the compression chamber (9) and is used for compressing mixed gas into any combustion chamber and igniting the mixed gas in the combustion chamber to enable the rotor (11) to rotate; the output shaft of the rotor (11) is connected with the crank of the crank sliding block mechanism through a transmission mechanism.

2. A two-stroke engine according to claim 1, wherein the compression chamber (9) communicates with the rotor cavity (10) through a reducer; an air inlet channel (7) is arranged on the reducing pipe, and a check valve (8) is installed on the air inlet channel (7) and used for preventing backflow in the compression process.

3. A two-stroke engine according to claim 2, wherein the slider (12) of the crank-slider mechanism (2) is tapered at one end and the tapered end of the slider (12) is fitted to the reducer for compressing the entire mixture of gases in the compression chamber (9) into the combustion chamber.

4. A two-stroke engine according to claim 1, wherein the cylinder block (1) is fitted with exhaust means for forced exhaust.

5. A two-stroke engine according to claim 4, wherein the exhaust mechanism comprises an exhaust baffle (14) and an elastic return device, the cylinder (1) is provided with an exhaust passage (6) communicated with any combustion chamber, the exhaust baffle (14) is arranged in the wall surface of the rotor cavity (10) near the exhaust passage (6), and the elastic return device is used for ensuring that one end of the exhaust baffle (14) is tightly attached to the profile of the rotor (11).

6. A two-stroke engine according to claim 1, wherein the transmission is a gear train.

7. A two-stroke engine according to claim 6, wherein the gear train comprises a first gear (3), a second gear (4) and an idler gear (5); the first gear (3) is connected with a crank of the crank sliding block mechanism; the output shaft of the rotor (11) is connected with a second gear (4), and the first gear (3) and the second gear (4) are respectively meshed with an idler gear (5).

8. A two-stroke engine according to claim 6, wherein the gear ratio of the first gear wheel (3) to the second gear wheel (4) is 1: 3; the wall surface of the rotor cavity (10) and the rotor (11) form 3 combustion chambers; through a gear train, the rotor (11) rotates for 1 circle, and a sliding block (12) of the slider-crank mechanism (2) reciprocates for 3 times in the compression chamber (9).