What unit is used to represent engine speed?

[Leo]

Automobile engine speed: represented by n, with the unit r/min. Here is relevant information about engine speed: Engine speed: The level of engine speed relates to the number of work cycles per unit time or the effective power output of the engine, meaning the engine's effective power varies with different speeds. Therefore, when stating the effective power of an engine, the corresponding speed must also be specified. The effective power and its corresponding speed specified on the engine's product nameplate are referred to as the rated power and rated speed, respectively. The operating condition of the engine at rated power and rated speed is called the rated condition. Rated power is not the maximum power the engine can produce but the maximum usable limit of effective power determined based on the engine's purpose. For the same engine model, the rated power value may differ depending on its intended use. Effective torque also varies with engine conditions. Therefore, the maximum torque an automobile engine can output and its corresponding speed are used as an indicator to evaluate the engine's dynamic performance. Speed measurement: Typically, a speed sensor is used, corresponding to the signal teeth on the flywheel, to measure the engine's speed. Speed range: During idle, the engine speed generally ranges from 700-1100 r/min.