WO2022236480A1

WO2022236480A1 - Cylinder piston unit for layered scavenging two-stroke engine

Info

Publication number: WO2022236480A1
Application number: PCT/CN2021/092407
Authority: WO
Inventors: 胡全宇
Original assignee: 永康市茂金园林机械有限公司
Priority date: 2021-05-08
Filing date: 2021-05-08
Publication date: 2022-11-17

Abstract

A cylinder piston unit (1) for a layered scavenging two-stroke engine. The cylinder piston unit comprises: a cylinder (2), wherein the cylinder (2) has cylinder air storage chambers (7, 8) and cylinder mixed gas storage chambers (5, 6), which are arranged independent of each other; and a piston (23) having a fully closed channel, wherein the piston (23) is configured to move up and down inside the cylinder (2). In actual use, pure air can be isolated from being mingled and mixed with a combustible mixed gas, and the amount of pure air stored in the cylinder (2) is also increased. During scavenging, the scavenging quality, the scavenging efficiency and the scavenging utilization rate are significantly improved, and emission of the combustible mixed gas along with tail gas is reduced, thereby significantly reducing harmful compounds such as HC and CO in the tail gas.

Description

A cylinder-piston unit for a stratified scavenging two-stroke engine

technical field

The invention relates to the field of engines, in particular to a cylinder-piston unit for a stratified scavenging two-stroke engine.

Background technique

At present, the cylinders of stratified scavenging two-stroke engines all adopt the method of pre-storing a part of air in the left and right scavenging passages of the cylinder. After the piston reaches the top dead center, it goes down. The scavenging ports on both sides of the cylinder are also gradually opened, and the air stored in the scavenging passage first enters the combustion chamber to scavenge first, reducing the uncombusted mixed gas that is discarded and discharged, thereby reducing the discharge of harmful gases such as HC and CO in the exhaust gas. For example, ZL201910211119.6 discloses a cylinder block of a stratified scavenging two-stroke gasoline engine. The cylinder block of the two-stroke gasoline engine of this invention mainly comprises a cylinder body, side cover 1, side cover 2, side cover 1 cooperates with the cylinder body to form a pure air storage chamber, and side cover 2 cooperates with the cylinder body to form another A pure air storage room. When the piston is scavenging downwards, the mixed gas quickly pushes the pure air in the pure air storage chamber into the combustion chamber through the scavenging air restriction hole, and occupies the fresh gas impulse in the exhaust gas faster, greatly reducing the content of compounds such as HC and CO in the exhaust gas. To achieve the purpose of energy saving and emission reduction. Tests have shown that when the machine is running at high speed, although the patented cylinder body is scavenging, combined with the restrictor holes in the scavenging channel, the emission of harmful components in the exhaust gas can be reduced to a certain extent, but the air and the mixed gas share the same scavenging channel , resulting in the intermixing and mixing of air and mixed gas in the scavenging channel. During scavenging, not only air but also unburned mixed gas participate in the exhaust gas discharge. As a result, the purification of harmful compounds such as HC and CO in the exhaust gas is not obvious. Not conducive to environmental protection.

For example ZL201610350517.2, the semi-closed inner channel provided by the piston pre-stores air. When the piston moves upward in the cylinder, the air enters the semi-closed channel of the piston from the intake channel, and then enters the scavenging channel, and then the mixed gas is released from the mixed gas. The channel enters the scavenging channel. When scavenging, the air will be cleaned first, and then the mixed gas will be cleaned. Gas efficiency, reducing the emission of harmful gases such as HC and CO in the exhaust gas. However, the test shows that when the machine is running at high speed, only a small amount of pre-stored air in the semi-closed inner channel enters the scavenging channel for first scavenging, and the exhaust gas in the combustion chamber is not completely cleaned, and the mixed gas in the latter stage continues to clean the exhaust gas. Part of the mixed gas will be lost with the exhaust gas; and because the semi-closed channels on both sides of the piston are connected, the pre-stored air and mixed gas in the scavenging channel are communicated through the semi-closed channel of the piston, resulting in intermixing and mixing of the gases , not only air, but also unburned mixed gas participate in the discharge of exhaust gas during scavenging. As a result, the purification of harmful compounds such as HC and CO in the exhaust gas is not very obvious, which is not conducive to environmental protection.

Contents of the invention

In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is that the existing cylinder and piston unit air and mixed gas share the scavenging channel, or the open channel or semi-closed channel in the piston causes the air and mixed gas to Doping, resulting in unburned mixed gas participating in the exhaust gas discharge, which is not conducive to environmental protection. The invention provides a cylinder-piston unit for a stratified scavenging two-stroke engine, which has an exclusive pure air storage room and an exclusive mixed gas storage room in the cylinder block to isolate the pure air and combustible mixed gas from intermixing. Mixing, and maximally increasing the storage capacity of pure air in the cylinder air storage room, increasing the storage capacity of pure air in the cylinder air storage room, greatly improving the quality of scavenging air, the efficiency of scavenging air, and the utilization of scavenging air The efficiency can reduce the phenomenon that the combustible mixture is discharged with the exhaust gas, thereby greatly reducing the harmful compounds such as HC and CO in the exhaust gas.

To achieve the above object, the present invention provides a cylinder-piston unit for a stratified scavenging two-stroke engine, comprising a cylinder with an independently arranged cylinder air storage chamber and a cylinder mixed gas storage chamber and an independent piston air storage chamber and the piston of the piston fully closed channel, the piston is set to move up and down inside the cylinder.

Further, the cylinder includes a cylinder body, a cylinder air storage room, a cylinder mixed gas storage room, a mixed gas scavenging port, a mixed gas channel, an air scavenging port, an intake channel, and an exhaust channel;

Wherein, the cylinder air storage chamber is arranged outside the cylinder body, the cylinder air mixture storage chamber is arranged outside the cylinder body, and the cylinder air storage chamber is arranged above the cylinder air mixture storage chamber in the cylinder axial direction;

One end of the mixed gas storage chamber of the cylinder communicates with the mixed gas scavenging port, and the other end communicates with the mixed gas passage; the air storage chamber communicates with the air scavenging port, and the exhaust channel and the intake channel are set to run through the cylinder body.

Further, the piston includes a piston body, and the outer edge of the piston body is provided with a piston air storage chamber and a piston fully-closed air channel, and the piston air storage room is arranged above the piston fully-closed air channel in the axial direction of the piston.

Further, the fully closed air channel of the piston is located on the intake side of the piston skirt.

Further, the fully closed air channel of the piston is set to have a tunnel opening on one side connected to the tunnel opening on the other side with the shortest irregular channel; preferably, the fully closed air channel of the piston is set to have a tunnel opening on one side of the piston air intake direction Connect to the tunnel entrance on the other side with the shortest irregular passage

Further, there are two piston air storage chambers, which are balanced and symmetrical.

Further, there are two fully closed air passages for the piston, which are balanced and symmetrical.

Further, the piston air storage chamber is arranged above the tunnel opening on one side of the fully closed piston air passage; preferably, the piston air storage chamber is arranged above the tunnel opening on one side of the piston air inlet direction of the fully closed piston air passage.

Further, there are two cylinder air storage chambers, which are balanced and symmetrically arranged; the total volume range of the two cylinder air storage chambers is set to be 0.8-3.5cc.

Further, the opening time of the air scavenging port is α later than the opening time of the exhaust port of the exhaust channel in terms of crank angle, α=2-12 degrees; the opening time of the mixed air scavenging port is β later than the opening time of the air scavenging port , β=0.5～13 degrees.

technical effect

The cylinder-piston unit for a stratified scavenging two-stroke engine of the present invention has an exclusive pure air storage room and an exclusive mixed gas storage room in the cylinder block, which isolates the pure air and the combustible mixed gas from mixing with each other, and The pure air storage capacity in the air storage room in the cylinder is increased to the greatest extent, and there are exclusive air scavenging ports and exclusive mixed air scavenging ports in the cylinder body. During the upward movement of the piston, the piston fully enclosed air passage and the piston's air storage room, The amount of pure air stored in the air storage chamber of the cylinder is increased. When scavenging, there is a large amount of pure air in the air storage chambers on both sides of the cylinder to clean the exhaust gas first, and then the mixed gas is cleaned, which greatly improves the quality and efficiency of the scavenging air. , The utilization rate of scavenging gas can reduce the discharge of combustible mixed gas with the exhaust gas, thereby greatly reducing the harmful compounds such as HC and CO in the exhaust gas.

The idea, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings, so as to fully understand the purpose, features and effects of the present invention.

Description of drawings

Fig. 1 is a schematic diagram of a cylinder-piston unit for a stratified scavenging two-stroke engine of a preferred embodiment of the present invention;

Fig. 2 is a left view of a cylinder-piston unit for a stratified scavenging two-stroke engine of a preferred embodiment of the present invention;

Fig. 3 is the right side view of a kind of cylinder-piston unit for stratified scavenging two-stroke engine of a preferred embodiment of the present invention;

Fig. 4 is a cylinder sectional view of a cylinder-piston unit for a stratified scavenging two-stroke engine of a preferred embodiment of the present invention;

Fig. 5 is a right side view of a piston of a cylinder-piston unit for a stratified scavenging two-stroke engine according to a preferred embodiment of the present invention;

Fig. 6 is a front view of a piston of a cylinder-piston unit for a stratified scavenging two-stroke engine according to a preferred embodiment of the present invention;

Fig. 7 is a kind of air direction schematic diagram of the cylinder-piston unit that is used for stratified scavenging two-stroke engine of a preferred embodiment of the present invention;

Fig. 8 is a schematic diagram of the air direction of a cylinder-piston unit for a stratified scavenging two-stroke engine according to a preferred embodiment of the present invention;

Fig. 9 is a schematic cross-sectional view of a cylinder-piston unit for a stratified scavenging two-stroke engine according to a preferred embodiment of the present invention;

Fig. 10 is a schematic diagram of the air direction of a cylinder-piston unit for a stratified scavenging two-stroke engine according to a preferred embodiment of the present invention.

Detailed ways

As shown in Figures 1-10, the embodiment of the present invention provides a cylinder-piston unit 1 for a stratified scavenging two-stroke engine, including a cylinder 2 and a cylinder air storage chamber and a cylinder mixture storage chamber provided independently. There is an independent piston air storage chamber and a piston 23 with a fully closed piston channel, and the piston 23 is arranged to move up and down inside the cylinder 2 .

Wherein, the cylinder includes a cylinder body, cylinder

air storage chambers

7 and 8, cylinder

mixture storage chambers

5 and 6, mixture

gas scavenging ports

9 and 10,

mixture air passages

13 and 14, air scavenging ports 11 and 12, intake passages, Exhaust channel 15;

Among them, as shown in Figures 2 and 3, the cylinder

air storage chambers

7 and 8 are arranged outside the cylinder body, the cylinder

mixture storage chambers

5 and 6 are arranged outside the cylinder body, and the cylinder

air storage chambers

7 and 8 are arranged on the cylinder shaft. Set upward above the cylinder

mixture storage chambers

5 and 6;

One end of the cylinder mixed gas storage chamber communicates with the mixed

gas scavenging ports

9 and 10, and the other end communicates with the mixed

gas passages

13 and 14; the cylinder air storage chamber communicates with the air scavenging port, and the exhaust passage and intake passage are set to run through the cylinder body .

The cylinder air storage chamber is composed of an inwardly recessed cavity on the outside of the cylinder block and a scavenging cover covering the cavity. The cylinder air storage chamber communicates with the inner cavity of the cylinder block through the air scavenging port.

The intake channel is divided into upper and lower layers, the upper layer is the

air intake channel

20, 21 of the cylinder, the lower layer is the air intake channel of the cylinder mixture, and a dividing plate is arranged between the upper layer and the lower layer. The part where the cylinder air intake channel intersects and penetrates the cylinder block is called the cylinder air intake port, and the part where the cylinder air intake channel intersects and penetrates the cylinder block is called the cylinder air intake port.

There are two cylinder air storage chambers, which are balanced and symmetrical; the total volume range of the two cylinder air storage chambers is set at 0.8-3.5cc. The opening time of the air scavenging port is α later than the opening time of the exhaust port of the exhaust passage on the crankshaft angle, α=2～12 degrees; the opening time of the mixed air scavenging port is β later than the opening time of the air scavenging port, β= 0.5 to 13 degrees.

The piston 23 includes a piston body, the outer edge of the piston body is provided with piston

air storage chambers

24, 25 and piston fully

closed air passages

26, 27, and the piston

air storage chambers

24, 25 are arranged on the piston fully closed type in the axial direction of the piston. Above the

air channels

26,27. Piston fully

closed air passages

26, 27 are provided on the intake side of the piston skirt. The fully-closed air channel of the piston is set so that the tunnel mouth on one side is connected to the tunnel mouth on the other side by the shortest irregular channel. to the other side of the tunnel.

There are 2 piston air storage chambers, which are balanced and symmetrical. There are 2 fully-closed air passages for the piston, which are balanced and symmetrical. The piston air storage chamber is arranged above the tunnel opening on one side of the piston fully-closed air passage, and in this embodiment, it is arranged above the tunnel opening on one side of the piston fully-closed air passage in the direction of piston intake.

The piston air storage chamber of the piston is in the same side direction as the cylinder air intake passage, and the piston air storage chamber of the piston and the cylinder air storage chamber of the cylinder form an angle close to the vertical bisector, and the piston air storage chamber of the piston and the cylinder air storage chamber of the cylinder The air storage chamber is 90°; the piston air storage chamber of the piston and the cylinder air mixture storage chamber are in an angle close to the vertical bisector, and the cylinder air mixture storage chamber and the cylinder air storage chamber are in the same side direction, and are arranged on the cylinder air Below the storage room.

The pistons in the cylinder-piston unit move upward in sequence, and the pure air enters the piston air storage room for pre-storage through the cylinder air intake channel and the cylinder air intake port first, and the pistons continue upward in sequence, and when they reach a position, the pure air in the cylinder air intake channel The air and the pure air pre-stored in the piston storage room are sucked into the fully closed air channel of the piston through the intake end of the fully closed air channel of the piston, and stored in the air storage room of the cylinder; The port is opened, and the mixed gas is communicated to the cylinder mixed gas passage through the crank chamber, and stored in the cylinder mixed gas storage chamber.

When the piston goes up, pure air enters the upper edge of the piston air storage chamber than enters the upper edge of the air inlet end of the fully closed air channel of the piston, and the time is α earlier on the crank angle, and α=12～34 degrees. When the piston descends in sequence, the upper edge of the piston opens the exhaust port in the cylinder body in sequence, then opens the cylinder air scavenging port, and then opens the cylinder mixed gas scavenging port, so that the stratified air is cleaned first, and the mixed gas is cleaned again.

The specific implementation of the cylinder-piston unit for the stratified scavenging two-stroke engine of the embodiment of the present invention will be described below:

When the piston moves upward in sequence, the air inlet in the cylinder body is opened, and the

air intake channels

20 and 21 are combined, pure air is sucked into the fully closed air channel of the piston under the action of atmospheric pressure, and stored in the air in the cylinder body 2. The

storage chambers

7, 8 are compressed and stored.

When the piston continues to move up in sequence, the lower edge of the piston opens the mixed gas inlet in the cylinder body, and after the mixed gas inlet channel is combined, the combustible mixed gas enters the crank chamber under the action of atmospheric pressure.

When the piston continues to move up to the top dead center in sequence, the spark plug emits electric sparks to ignite the mixed gas compressed in the combustion chamber 17 in the cylinder body, and the high-temperature and high-pressure gas after combustion forces the piston to go down, closing the cylinder body in sequence Inner mixed gas intake port, air intake port; at this time, the combustible mixed gas sucked into the crankshaft chamber is pre-compressed due to the downward movement of the piston, and positive pressure is formed in the crankshaft chamber, and the combustible mixed gas in the crankshaft chamber is compressed into the

mixed gas Passages

13, 14 are stored in the mixed

gas storage chambers

5, 6 in the cylinder body for compressed storage.

When the piston descends in sequence, the exhaust port in the cylinder body is opened, and part of the exhaust gas flows into the muffler through the exhaust passage 15 and is discharged into the atmosphere.

When the piston continues to descend, the air scavenging ports 11 and 12 in the cylinder body are opened, and the pure air is prestored in the

air storage chambers

7 and 8 in the cylinder body.

Gas ports

9 and 10 are pre-stored combustible mixed gas in the mixed

gas storage chambers

5 and 6 in the cylinder body and enter the combustion chamber 17 for scavenging. Since there are symmetrical exclusive

air storage chambers

7 and 8 and exclusive mixed gas storage chambers on both sides of the

cylinder body

5, 6 Balanced layout structure, isolated from pure air and combustible gas mixture mixed with each other, can greatly increase the pure air storage capacity of

air storage chamber

7, 8, and symmetrical exclusive air scavenging ports 11, 12 on both sides of the cylinder body And the balanced arrangement of the exclusive mixed

gas scavenging ports

9 and 10 greatly improves the good scavenging efficiency and reduces the phenomenon that the incompletely combusted mixed gas is discharged with the exhaust gas, thereby effectively reducing HC, CO and other harmful compounds in the exhaust gas.

The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make many modifications and changes according to the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall be within the scope of protection defined by the claims.

Claims

A cylinder-piston unit for a stratified scavenging two-stroke engine is characterized in that it includes a cylinder with an independently arranged cylinder air storage chamber and a cylinder mixed gas storage chamber and has an independent piston air storage chamber and a fully closed piston The piston of the channel is arranged to move up and down inside the cylinder.
A cylinder-piston unit for a stratified scavenging two-stroke engine according to claim 1, wherein the cylinder comprises a cylinder body, a cylinder air storage chamber, a cylinder mixed gas storage chamber, a mixed gas scavenging port, Mixed air channel, air scavenging port, intake channel, exhaust channel;

Wherein, the cylinder air storage chamber is arranged on the outside of the cylinder body, the cylinder mixed gas storage chamber is arranged on the outside of the cylinder body, and the cylinder air storage chamber is arranged on the cylinder axial direction. above the cylinder mixture storage chamber;

One end of the cylinder mixed gas storage chamber communicates with the mixed gas scavenging port, and the other end communicates with the mixed air passage; the cylinder air storage chamber communicates with the air scavenging port, and the exhaust passage, the The intake passage is arranged to pass through the cylinder body.
A cylinder-piston unit for a stratified scavenging two-stroke engine as claimed in claim 1, wherein the piston comprises a piston body, and the outer edge of the piston body is provided with a piston air storage chamber and a fully closed piston unit. An air channel, the piston air storage chamber is arranged above the fully closed air channel of the piston in the axial direction of the piston.
A cylinder-piston unit for a stratified scavenging two-stroke engine according to claim 1, wherein the fully closed air passage of the piston is located on the intake side of the piston skirt.
A kind of cylinder-piston unit for stratified scavenging two-stroke engine as claimed in claim 4, it is characterized in that, said piston fully closed air channel is set to have one side tunnel mouth with the shortest irregular channel, connected to The tunnel entrance on the other side.
A cylinder-piston unit for a stratified scavenging two-stroke engine according to claim 3, wherein the number of said piston air storage chambers is set to two, and are balanced and symmetrical.
A cylinder-piston unit for a stratified scavenging two-stroke engine according to claim 4, wherein the number of fully closed air passages for the pistons is two, and they are balanced and symmetrical.
A cylinder-piston unit for a stratified scavenging two-stroke engine according to claim 5, wherein the piston air storage chamber is arranged above the tunnel opening on one side of the fully closed air passage of the piston .
A cylinder-piston unit for a stratified scavenging two-stroke engine as claimed in claim 2, wherein said cylinder air storage chambers comprise two, and are arranged symmetrically; said two cylinder air storage chambers The total volume range of the set is 0.8 ~ 3.5cc.
A cylinder-piston unit for a stratified scavenging two-stroke engine according to claim 2, wherein the opening time of the air scavenging port is greater than the opening time of the exhaust port of the exhaust passage on the crankshaft angle Late by α, α = 2-12 degrees; the opening time of the mixed air scavenging port is β later than the opening time of the air scavenging port in terms of crank angle, β = 0.5-13 degrees.