ENGINE OPERATION Intake lobe moves out of cavity with intake valve open,
drawing in fresh air-fuel mixture. | COMPRESSION both valves are closed. Next lobe moves in, compressing mixture. |
POWER spark plug ignites mixture. Heat expands gases and pressure drives lobe outward, turning crank. | EXHAUST Lobe enters the cavity, exhaust valve opens. Sweeping out the burned exhaust gases and cycle begins again. |