The operating cycle of the Renesis rotary engine is the same as a conventional, or Wankel, rotary engine, but with some design changes that improve fuel economy under load and compliance with current emission regulations.
There is a low output version of this engine for use with automatic transmissions and a high output version for use with manual transmissions.
The low output Renesis engine has 2 intake ports, primary and secondary, and these have been enlarged and moved to the side of the housing. In this position they are able to open sooner, improving power and torque and extending engine efficiency over a wider engine speed range.
The intake manifold has primary, secondary and auxiliary ducts. The primary duct has no control valve, the secondary and auxiliary ducts are controlled by butterfly valves.
At low engine speeds, air flows into the engine through the primary intake ducts only, keeping the air velocity in the manifold high, which provides better air fuel mixing.
At medium engine speeds, and when engine load is high enough, the secondary intake ducts are opened by butterfly valves, reducing restriction and increasing airflow and torque.
At high engine speeds, an extra air duct opens on the air cleaner allowing more air to be drawn into the engine.
The high output engine has 3 intake ports, primary, secondary and auxiliary. At engine speeds above 6000 rpm the auxiliary duct opens, allowing the engine to draw air in through all 6 ports, further increasing engine breathing.
A butterfly valve located between each housing's main intake duct is used at speeds above 7000 rpm to shorten the effective length of the intake tubes so that pressure pulses force more air into the engine.
Low output engines have 2 fuel injectors per rotor, primary and secondary. The primary fuel injectors operate at all times, the secondary injectors operate at engine speeds over 3700 rpm and when the engine load demands more fuel.
The high output engine has additional primary injectors, named primary 2, which only operate at very high speed and load conditions.
The exhaust ports in a Renesis engine have also been enlarged and moved from to the side of the combustion chamber housing. In this location the exhaust ports opening open later than in a conventional rotary engine, and the rotor has been machined to delay the closing point. These changes deliver a longer expansion stroke and increase thermal efficiency.