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Old 09-19-2008, 10:13 PM   #8 (permalink)
NeilBlanchard
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Hi,

Some additional info on the Revetec engine:

Revetec Development page 1
Revetec Development page 2

Quote:
Another feature of the Revetec engine is that 60% of downward force applied to the main journal via the crankshaft is deflected to rotational force increasing efficiency in the Revetec engine. The image to the left shows the bearings under the piston (Note: The second bearing on the reverse rotating cam is hidden behind the front bearing - side by side). As the piston pushes down on the bearing the load (shown in yellow) forces the trilobe cams to spread. The deflected force is deflected into the opposing counter-rotating trilobe cam. The contact angle between the point of bearing contact (shown in purple) produces the torque lever (shown in red). The trilobe and bearing sizes determine how long the high leverage occurs and is designed for each individual engine characteristic we are wanting to achieve.

The Revetec “trilobate” design is very different in regards to piston position in the compression and ignition areas. The down stroke is the same as a conventional engine. The difference is that the travel of the piston on the up stroke is reversed, meaning that at 90deg after BDC the piston moves over half the way up the stroke at the equivalent point of a crankshaft rotating 90degrees. This results in the piston travelling faster initially than a conventional engine. The result of this phenomenon is that when the cylinder is fired, the piston is closer to TDC than a conventional engine. This provides more fuel molecules between the spark plug. We then reduce the amount of fuel (leaner mixture) to provide the correct firing mixture. This feature is most noticeable between the 2,000-4,000rpm range, where most driving occurs. This feature also increases thermal efficiency within the chamber. Another feature of extended dwell is that in a conventional engine, it is normal to inject up to 60% more fuel on a cold start. We have been able to reduce this down to 7% more fuel, reducing cold start fuel consumption and emissions.
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