| Downward gear engagement in which the input shaft and output shaft are locked together; the gearing in the drivetrain in which one turn of the crank shaft equals one turn of the wheel. | |
| The lower Engine part with main rod bearing journals. It converts reciprocating motion to rotary motion. | |
| A device that atomizes air and fuel in a proportion that is burnable in the engine. | |
| The process of a vapor becoming a liquid; the opposite of evaporation. |