JPS588907Y2 - Souji Youkiyukiyuki 2-stroke engine - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a simple structure for guiding two types of air-fuel mixtures having different air-fuel ratios to a combustion chamber in a crank chamber compression type two-stroke engine.

A two-stroke engine with crank chamber compression uses a carburetor.

The air-fuel mixture generated by a fuel injection device, etc. is sucked into the crank chamber by the negative pressure generated in the crank chamber during the upward stroke of the piston, and then compressed during the downward stroke of the piston and forced into the combustion chamber through the scavenging passage. It is activated by igniting and exploding.

On the other hand, stratified air supply engines feed a mixture with a richer air-fuel ratio to the vicinity of the ignition plug in the combustion chamber, thereby creating a relatively lean mixture without impairing the ignitability of the ignition plug. It operates on a mixture of fuel and fuel to improve fuel economy and reduce emissions of air pollutants in the exhaust.

However, as described above, when attempting to suck two rich and light mixtures into the crank chamber at the same time and forcefully feed them to the combustion chamber, the two mixtures mix in the crank chamber, making it impossible to achieve the intended purpose.

This invention eliminates the above-mentioned conventional problems and improves it. According to this invention, between the piston and the crankshaft, the inside of the crank chamber below the piston top wall that constitutes the combustion chamber,
When the piston reaches the bottom dead center, it is divided into upper and lower chambers that communicate through the connecting rod insertion hole using a wall material provided directly below the skirt of the piston, and the upper and lower chambers have a scavenging passage leading to the combustion chamber and the atmosphere. The intake passage in one chamber is connected to a fuel supply device such as a carburetor for a rich mixture, and the intake passage in the other chamber is connected to a fuel supply device such as a carburetor for a rich mixture, and the intake passage in the other chamber is connected to a vaporizer that supplies a lean mixture or only air as needed. A stratified air charge type two-stroke engine is provided which is connected to a fuel supply device such as a fuel tank.

In this invention, it is possible to decide as necessary whether to supply rich or lean air-fuel mixture to the upper and lower chambers, and how to determine the flow rate ratio. The position and direction of the opening can also be determined as necessary.

Furthermore, depending on the operating conditions, the fuel addition nozzle that generates a lean mixture can be used to suck only air into the engine without adding fuel, and the generation of the mixture is not limited to the carburetor. It is also possible to use fuel injection devices.

Embodiments of this invention will be described below with reference to the accompanying drawings.

The engine E is provided with an intake passage 4 equipped with a reed valve 2 connected to a rich mixture air carburetor C1, and a lean air mixture or air carburetor C2 installed in parallel with the rich air mixture carburetor C1. An intake passage 6 is provided which connects to the air intake passage 6.

The cylinder wall 10 of the combustion chamber 8 of the engine E is provided with a scavenging passage 12 that communicates with the intake passage 4 for rich air-fuel mixture. Negative pressure is generated, but initially the intake passage 6 is connected to the piston 1.
6, no lean mixture or air is sucked into the upper chamber 17, and the negative pressure is passed through the connecting rod insertion hole 22 to the lower chamber 19, and the negative pressure allows it to pass below the intake passage 4 and the scavenging passage 12. The rich air-fuel mixture is guided into the lower chamber 19.

Subsequently, the piston 16 further rises, and when the intake passage 6 is opened, a lean mixture or air is sucked into the upper chamber 17, and this state continues until immediately after the piston 16 reaches the top dead center and starts the downward stroke.

On the other hand, when the piston 16 descends, the pressure in the crank chamber 18 increases, and the air-fuel mixture sucked into the upper chamber 17 and the lower chamber 19 is compressed and sent separately into the combustion chamber 8 through the scavenging passages 12.14.

In this case, the positions and directions of the openings on the combustion chamber 8 side of the scavenging passages 12 and 14 are set appropriately so that the lean mixture or air moves downward and the rich mixture moves upward, so-called "stratification". Air is supplied.

In the figure, 20 is a spark plug, 24 is a connecting rod, and 26 is an exhaust hole.

Since this invention is implemented as described above, the piston 16
The connecting rod insertion hole 22 through which the connecting rod 24 passes during the upward stroke of the
The negative pressure generated in the upper chamber 17 of the crank chamber 18 is also transmitted to the lower chamber 19 through the upper and lower chambers 17 and 19, respectively. can.

At this time, the mixtures of the two upper and lower units 17.19 mix slightly through the insertion hole 22, but the degree of mixing can be adjusted to a small degree by appropriately setting the volume of the chamber 17.19 and the intake air amount ratio.

Also, due to the downward stroke of the piston 16, the crank chamber 18
The pressure increase that occurs in the upper chamber 17 also passes through the insertion hole 22 to the lower chamber 19, and the mixture is forced into the combustion chamber 8 through the scavenging passages 12 and 14 by the upper and lower units 17 and 19, respectively. can.

According to this invention, a simple structure in which a wall member is provided below the piston 16 has the effect of making it possible to compress the crank chamber 18 while preventing mixing of two types of air-fuel mixtures having different air-fuel ratios.

[Brief explanation of the drawing]

The figures show an embodiment of this invention. Figure 1 is a vertical cross-sectional side view when the piston reaches the bottom dead center of the crank chamber, and Figure 2 is a sectional view taken along the line ■-■ in Figure 1. Figure 3 is the line in Figure 2■
- It is a partial cross-sectional view according to ■. In the figure, the symbols necessary to understand this invention are shown as E.
C1 is an engine, C1 is a rich mixture carburetor, C2 is a lean mixture carburetor, 4 is an intake passage for rich mixtures, 6 is an intake passage for lean mixtures, 8 is a combustion chamber, 10 is a cylinder wall, 12. 14 is a scavenging passage, 16 is a piston, 17 is an upper chamber of the crank chamber 18, 19 is a lower chamber of the crank chamber 18, and 22 is a connecting rod insertion hole.

Claims (1)

[Scope of utility model registration request] Inside the crank chamber 18 below the piston 16 that constitutes the combustion chamber 8 of the engine E, between the piston 16 and the crankshaft,
When the piston 16 reaches the bottom dead center, a wall material provided directly below the skirt of the piston 16 divides the piston 16 into an upper chamber 17 and a lower chamber 19 that communicate through the connecting rod insertion hole 22. 19 is provided with a scavenging passage 12 communicating with the intake passage 4, the upper chamber 17 is provided with an intake passage 6 and a scavenging passage 14, and one of the intake passages 4, 6 is provided with a scavenging passage 12 for supplying a rich mixture. A stratified air supply type two-stroke engine comprising a fuel supply device C1 and a fuel supply device C2 for supplying a lean mixture on the other hand.