Variable Displacement – Flexible New Technology!

A very powerful feature of the RoundEngine is the ability to vary

• the displacement for each compression stroke and
• the length of the expansion or power stroke.

In other words, the RoundEngine has true displacement on demand.

By being able to make the expansion stroke longer than the compression stroke, the size of the PV diagram can be increased thereby resulting in greater energy efficiency.   In terms of the compression stroke, two volumes can be varied:   

[1] Toroidal volumes: The RoundEngine can have multiple inlet ports such as per inlet I and II.  The choice of port is impacted by the load facing the engine and can be switched during operations. In this way, the volume at the beginning of the compression stroke, and thus the displacement, can be smaller (use inlet port I) or larger (inlet port II).

[2] Combustion chamber volumes: As the combustion chamber is external to the toroid, the actual working internal volume within the chamber can be increased, or decreased. This feature has more of an impact on fuel choice and compression ratios, but nonetheless can also be used to some degree to impact displacement.