Difference between revisions of "Two stroke"

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[[Image:Arbeitsweise Zweitakt.gif|thumb|left|550px|A two-stroke engine, in this case with a [[tuned pipe|tuned expansion pipe]] illustrating the effect of a reflected pressure wave on the fuel charge. This feature is essential for maximum charge pressure (volumetric efficiency) and fuel efficiency. It is used on most high-performance engine designs.]]
[[Image:Arbeitsweise Zweitakt.gif|thumb|left|550px|A two-stroke engine, in this case with a [[tuned pipe|tuned expansion pipe]] illustrating the effect of a reflected pressure wave on the fuel charge. This feature is essential for maximum charge pressure (volumetric efficiency) and fuel efficiency. It is used on most high-performance engine designs.]]


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===
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===Crossflow-scavenged===
===Crossflow-scavenged===
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 This design has been largely superseded by loop scavenging method (below), although for smaller or slower engines the crossflow-scavenged design can be an acceptable approach.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]]  
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