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Difference between revisions of "Two stroke"
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Although the principles remain the same, the mechanical details of various two-stroke engines differ depending on the type. The design types of the two-stroke engine vary according to the method of introducing the charge to the cylinder, the method of scavenging the [[cylinder (engine)|cylinder]] (exchanging burnt exhaust for fresh mixture) and the method of exhausting the cylinder. | Although the principles remain the same, the mechanical details of various two-stroke engines differ depending on the type. The design types of the two-stroke engine vary according to the method of introducing the charge to the cylinder, the method of scavenging the [[cylinder (engine)|cylinder]] (exchanging burnt exhaust for fresh mixture) and the method of exhausting the cylinder. | ||
===Reed inlet valve=== | ===Reed inlet valve=== | ||
{{Main|Reed | {{Main|Reed Inlet Valve}} | ||
The reed valve is a simple but highly effective form of | The reed valve is a simple but highly effective form of check valve commonly fitted in the intake tract of the piston-controlled port. They allow asymmetric intake of the fuel-charge, improving power and economy, while widening the power band. They are widely used in ATVs, and marine outboard engines. | ||
===Rotary inlet valve=== | ===Rotary inlet valve=== | ||
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In a crossflow engine the transfer ports and exhaust ports are on opposite sides of the cylinder and a deflector on the top of the piston directs the fresh intake charge into the upper part of the cylinder pushing the residual exhaust gas down the other side of the deflector and out of the exhaust port. The deflector increases piston's weight and its exposed surface area, and also makes it difficult to achieve an efficient combustion chamber shape. This design has been largely superseded by loop scavenging method (below), although for smaller or slower engines the crossflow-scavenged design can be an acceptable approach. | In a crossflow engine the transfer ports and exhaust ports are on opposite sides of the cylinder and a deflector on the top of the piston directs the fresh intake charge into the upper part of the cylinder pushing the residual exhaust gas down the other side of the deflector and out of the exhaust port. The deflector increases piston's weight and its exposed surface area, and also makes it difficult to achieve an efficient combustion chamber shape. This design has been largely superseded by loop scavenging method (below), although for smaller or slower engines the crossflow-scavenged design can be an acceptable approach. | ||
==See Also== | ==See Also== | ||
*[[Rotary Disc Valve]] | * [[Rotary Disc Valve]] | ||
* [[Reed Inlet Valve]] | * [[Reed Inlet Valve]] | ||