CN2343354Y - Motorcycle two-stroke engine capable of stratified scavenging - Google Patents

Abstract

The utility model provides a motorcycle two-stroke engine of ability layering scavenging, includes cylinder and crankcase, is equipped with main air inlet in first one of crankcase and gas vent opposite direction department, and then is equipped with inferior air inlet on the cylinder wall, and this time air inlet and main air inlet within a definite time and be equipped with gas, vapour layering blend stop, establish in inferior air inlet near side and drive the gas port, the utility model discloses can effectively reduce and improve because of the high oil consumption that the oil gas short circuit caused and discharge pollution.

Description

Motorcycle two-stroke engine capable of stratified scavenging

The utility model relates to a motorcycle two-stroke engine, in particular to a motorcycle two-stroke engine capable of layered scavenging.

The general two-stroke engine has the advantages of small size, light weight, simple structure, easy manufacture and maintenance, low price, high power density and low cost. It has been loved by manufacturers and consumers in use. Boats, logging machines and even household lawn mowers use two-stroke engines. In addition, two-stroke diesel engines are also used in locomotives, trucks or chariots, showing the wide range of two-stroke engines; but due to their special The gas purging method causes about 25% to 40% of the fuel to be discharged without combustion due to short-circuiting, resulting in toxic carbon monoxide (CO) and hydrocarbons (HC) contained in the exhaust. It is higher than the four-stroke engine, and it is accompanied by the problem of high fuel consumption; in the face of increasingly stringent environmental protection standards, if we can try to reduce the exhaust pollution and high fuel consumption of the two-stroke engine, the two-stroke engine still has room for development.

Furthermore, the purging action of the two-stroke engine is to use the position of the piston in the cylinder to control the switch of the purging port and the exhaust port. Generally, there is no exhaust valve similar to the four-stroke engine. Therefore, at the end of the scavenging port, when the exhaust port Before the air port is closed, a lot of fresh oil and gas will be discharged to the outside, which not only causes the loss of horsepower, but also causes serious air pollution; the shortcomings of high emission pollution and high fuel consumption can be improved by improving the combustion system and exhaust system. The modification of the intake system is also a key point; it is estimated that the oil and gas loss of a general two-stroke engine due to a short circuit of oil and gas is about 25% to 40%; even if the scavenging design is very good, there will still be a lot Oil and gas waste and hydrocarbon pollution; so someone came up with the idea to solve this problem: During the scavenging and charging process, the mixed gas is replaced by pure air, and a certain amount of fuel is supplied to the cylinder after the exhaust port is completely closed. Among them, fuel injection is a method derived from this idea, but for motorcycle two-stroke engines, it also causes disadvantages such as high manufacturing difficulty, high price and expensive maintenance; if a motorcycle engine with a carburetor Therefore, it is an urgent task to develop a low-cost, simple and convenient method that can improve exhaust pollution.

In order to reduce the fuel consumption and exhaust pollution of two-stroke engines using carburetors, the method used in the past is to simply modify the existing traditional engines, hoping that the purging gas during scavenging will be a relatively thinner oil in the early stage Steam or pure air, and thick oil vapor in the later stage, reduce the leakage of fresh oil vapor during the purging process, so as to reduce fuel consumption and pollution. For example, in the Taiwan Invention Patent Announcement No. 325505, two air intakes are installed: one air intake is installed at the position farthest from the exhaust port under the crankcase, and the circular motion of the large end of the outer circumference of the crank wall is swept by the upward stroke of the piston. When this air inlet is used, the rich mixture can be sucked into the crankcase; the other air inlet is installed on either side of the line connecting the exhaust port and the first air inlet to draw the lean mixture. Or pure air is introduced into the crankcase. While this arrangement is somewhat effective, it has three main disadvantages:

First, in order to match the frame and exterior design of the motorcycle, most engines cannot arrange the inlets of the thick and lean mixtures at the position farthest from the exhaust port below the crankcase and on both sides.

Second, the entrance of the thick mixed gas must be on the path when the piston rises and the circular motion of the large end of the outer circumference of the crank wall sweeps the bottom air inlet to suck the rich mixed gas into the crankcase. In this way, the arrangement position is limited , and because there is a flywheel counterweight in the crankcase, the space is extremely small, and the thick mixed steam is subject to great flow resistance, so it is very difficult to introduce it, and there will be insufficient oil and steam.

Thirdly, for the sake of smooth ignition, lean mixed steam is used as the medium of the leading purge gas, and the design of thick mixed steam is injected into the cylinder later, but the problem of oil leakage can only be reduced by compromise.

The purpose of the utility model is to overcome the shortcomings of the above-mentioned prior art and provide a motorcycle two-stroke engine capable of layered scavenging, which can effectively reduce the high fuel consumption caused by oil-gas short circuit, improve the exhaust pollution of the engine, and make the gas , The layering effect of steam is better.

The technical scheme of the utility model is:

A motorcycle two-stroke engine capable of layered scavenging, comprising a cylinder and a crankcase, is characterized in that:

One side of the cylinder is provided with an exhaust port, the other side is provided with a secondary air inlet, and the cylinder is provided with a purge port near the secondary air inlet;

A crankcase, which communicates with the cylinder and is combined together. The crankcase is provided with a piston at the junction with the cylinder. A connecting rod is pivotally connected to the piston. The crankcase is in the upper half and opposite to the exhaust port. There is a main air inlet.

The motorcycle two-stroke engine capable of stratified air scavenging is characterized in that a gas and steam stratified bar is provided between the main air inlet and the secondary air inlet.

The said motorcycle two-stroke engine capable of layered scavenging is characterized in that: the gas and steam layer barrier is a bump.

The utility model has the following effects:

The utility model provides a motorcycle two-stroke engine capable of layered scavenging, which is provided with a main air inlet on the upper half of the crankcase and opposite to the exhaust port, and a secondary air inlet on the cylinder wall. Air port, when the crankcase sucks air, the pure air entering from the secondary air inlet will exist in the upper layer of the crankcase close to the purge air port, while the mixed air entering from the main air inlet will exist in the lower layer of the crankcase far from the purge air port, so as to When the piston is lowered and the purge port is opened, and the gas in the crankcase is compressed and injected into the cylinder due to the narrowing of the space, the pure air existing in the upper layer of the crankcase near the purge port will become the medium of the leading purge gas, and the exhaust gas will be released first. After being eliminated, the mixed gas originally present in the lower layer of the crankcase farther away from the purging port is raised for combustion. In this way, it can not only effectively reduce the high fuel consumption caused by oil-gas short circuit, but also improve emission pollution.

The utility model is provided with gas and vapor layered barrier strips on the upper half of the crankcase, near the lower edge of the cylinder and between the main air inlet and the secondary air inlet. The resistance of the mixed steam entering the crankcase to diffuse around the upper cylinder, and the resistance of the pure air entering the lower crankcase from the secondary air inlet on the upper cylinder wall, make the effect of gas and steam stratification better.

In order to further understand and understand the features and effects of the present utility model, the following examples are given in conjunction with the drawings, and the details are as follows:

Fig. 1 is a schematic structural view of an embodiment of the utility model.

Please refer to shown in Fig. 1, it is a kind of motorcycle two-stroke engine that can stratified scavenging, in the present embodiment is a crankcase 4 pre-compression type spark ignition type two-stroke engine, this engine top is provided with a cylinder head 1. The cylinder head 1 is connected with the cylinder 3 combined with it, and a spark plug 2 is inserted in the cylinder head 1, and one end of the spark plug 2 goes deep into the combustion chamber 31 of the cylinder 3, and the One side of the combustion chamber 31 is provided with an exhaust port 7, and the exhaust port 7 is connected with an exhaust pipe 8. In addition, a secondary air inlet 11 of a reed valve 111 is provided on the appropriate position of the cylinder 3. The air inlet 11 is connected with a throttle valve 12, the throttle valve 12 is mainly used to control the air flow entering the secondary air inlet 11, and the combustion chamber 31 of the cylinder 3 is provided with a drive valve on the near side of the secondary air inlet 11. Air port 14.

Furthermore, a connected crankcase 4 is connected under the cylinder 3, a piston 5 is arranged between the crankcase 4 and the cylinder 3, and a connecting rod 6 that can run in the crankcase 4 is pivoted on the piston 5. And this crankcase 4 is provided with a main air inlet 9 of a reed valve 91 on the upper half and the position opposite to the exhaust port 7, and this main air inlet 9 is connected with an oil supply device 10, in this In the embodiment, it is a carburetor.

In addition, on the inner wall between the upper half of the crankcase 4 and the lower edge of the cylinder 3, there is an air and steam stratification bar 13, which is a bump in this embodiment (those who are familiar with this technology can still replace it with other elements) .), the gas and steam stratification bar 13 is located between the main air inlet 9 and the secondary air inlet 11, the mixed gas in the main air inlet 9 enters the crankcase 4, and the gas mixture in the secondary air inlet 11 When pure air enters, it can be separated by gas and steam stratification baffles 13 respectively, so as not to rise or fall.

Please refer to Fig. 1, when the mixed steam enters from the main air inlet 9 through the oil supply device 10, the gas and steam layer barrier 13 can cause resistance to the mixed steam entering from the main air inlet 9, so that the mixed steam It is not easy to go up into the cylinder 3, and most of it will go down into the crankcase 4 and the space that increases with the upward movement of the piston 5; in addition, pure air enters from the throttle valve 12 through the secondary air inlet 11 At the same time, the gas and steam layer baffle 13 can cause resistance to the pure air entering by the secondary air inlet 11, so that the air is not easy to enter the crankcase 4 downwards, and most of it will lead to around the cylinder 3 and surround the cylinder 3. Purging air port 14, by arranging the position of main and secondary two air inlets 9,11 and gas, vapor layer baffle bar 13 in this way, when crankcase 4 is inflated, the pure air that enters by secondary air inlet 11 exists in The upper layer of the crankcase 4 is close to the purging port 14, and the mixed gas entered by the main air inlet 9 exists in the lower layer of the crankcase 4 far away from the purging port 14. In this way, when the piston 5 descends and the purging port 14 is opened, the crankcase 4 The gas inside is compressed and injected into the cylinder 3 due to the shrinkage of the space. At the same time, because pure air exists around the purging port 14 and the upper layer of the crankcase 4 is close to the purging port 14, it can become the medium of the leading purging gas. The combustion chamber 31 drives the exhaust gas to the exhaust port 7, and then when it is discharged from the exhaust pipe 8 connected to the exhaust port 7, the mixed gas that originally existed in the lower crankcase 4 and is far away from the purging port 14 will be released along with the piston 5. After running and rising at the same time, by adjusting the opening of the throttle valve 12 on the secondary air inlet 11, to obtain the best air intake ratio of the main and secondary air inlets 9 and 11, the combustion in the cylinder 3 Combustion in chamber 31, in this way, not only can effectively reduce the two major problems of high fuel consumption caused by short-circuiting and improve emission pollution without losing the advantages of high power density of the two-stroke engine, but also Without the difficulty of location arrangement, the effect is better.

Claims (3)

1. A motorcycle two-stroke engine capable of stratified scavenging, comprising a cylinder and a crankcase, characterized in that: One side of the cylinder is provided with an exhaust port, the other side is provided with a secondary air inlet, and the cylinder is provided with a purge port near the secondary air inlet; A crankcase, which communicates with the cylinder and is combined together. The crankcase is provided with a piston at the junction with the cylinder. A connecting rod is pivotally connected to the piston. The crankcase is in the upper half and opposite to the exhaust port. There is a main air inlet. 2. The motorcycle two-stroke engine capable of stratified air scavenging as claimed in claim 1, characterized in that: a gas and steam stratified bar is arranged between the main air inlet and the secondary air inlet. 3. The motorcycle two-stroke engine capable of layered scavenging as claimed in claim 2, characterized in that: the gas and steam layer bar is a bump.

Images