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New Design for Fuel Efficient Piston Engines
Home » Performance Evaluations 
Yoke-Arm Technology - Some Performance Evaluations
The following performance curves compare the differences between engines with the same stroke and displacement. The blue curves show what happens when you modify the same engine using the Fisher yoke-arm technology. These graphs, produced through computer modeling, were selected to show some of the surprising features of the yoke-arm technology.

Computer modeling shows a significant difference between piston dwells for Fisher vs. conventional. Yoke-arm design parameters can vary the amount of dwell to accomodate different engine applications.
  1. When calculating at approx. 15% travel of the down stroke (58.5 degrees crank rotation for Fisher) during combustion, the yoke-arm piston dwell for this particular engine configuration is about 40% more than that of conventional. That is enough to double the fuel economy.

  2. Also, the added benefits of higher piston compression velocities (not shown) promote greater air/fuel turbulence for extra combustion efficiencies that further contribute to fuel savings.

The yoke-arm reduces piston rod angularity which greatly decreases piston lateral forces and side loading for much less piston friction and increased mechanical efficiencies. Reduced rod angularity promotes less heat build-up which in turn promotes less piston and cylinder wear requiring less engine cooling. These benefits result in longer engine life and are especially relevant to air cooled engines such as motorcycles, aircraft, lawn & garden, and such.


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