The rotary engine is not as common as the 4-stroke or 2-stroke engine but its basic principle is well accepted. It operates very differently from a reciprocating engine.
A piston-engine is called reciprocating because the pistons move back and forth over the same path. This reciprocating motion changes into rotary motion at the crankshaft.
A rotary engine has a rotor, not a piston, and it’s called rotary because the rotor has a planetary motion. It does not reciprocate.
The rotor is roughly triangular in shape and it turns inside a housing which is a particular geometric shape called an epitrochoid curve.
Because it spins, rather than moves up and down, engine operation is said to be very smooth and vibration free.
Let’s look at basic principles of the rotary engine.
The rotary engine does look different but it is still an internal combustion engine, so let’s find the five key events common to all internal combustion engines.
Intake occurs when air-fuel mixture enters the working chamber at the inlet port.
The turning rotor then carries it around to the spark plugs. Along the way, the volume of the working chamber decreases, and compresses the mixture.
The mixture is ignited and combustion occurs. Expanding gases produce a power pulse, driving the rotor onward.
When the exhaust port is uncovered, exhaust occurs as the rotor sweeps burned gases out of the housing.
Which brings it all back to the beginning, ready to run a new cycle.
