varvtalsbegränsare

A varvtalsbegränsare, which translates to "revolution limiter" or "rev limiter" in English, is a safety device found in internal combustion engines. Its primary function is to prevent the engine from exceeding a predetermined maximum rotational speed, or RPM (revolutions per minute). This is crucial for protecting the engine from damage that can occur at excessively high RPMs, such as catastrophic mechanical failure of internal components.

The rev limiter operates by interrupting the engine's ignition system or fuel supply when the engine speed reaches the set limit. This interruption can be a complete cutoff or a pulsing action, momentarily cutting power to prevent further acceleration. Modern vehicles often have sophisticated electronic rev limiters controlled by the engine control unit (ECU), which can be programmed for different engine operating conditions. Older vehicles might employ mechanical or simpler electronic systems.

While primarily a protective measure, rev limiters also influence driving characteristics. In manual transmission vehicles, the rev limiter dictates the point at which a driver should shift gears to avoid over-revving. In racing applications, the rev limiter's setting is carefully chosen to optimize performance within the engine's safe operating range, balancing power output with durability. The presence and setting of a rev limiter are important considerations for engine longevity and performance tuning.