Ylikierroksella

Ylikierroksella is a Finnish term that translates to "overdrive" in English, often used in the context of vehicles. In automotive mechanics, overdrive refers to a gear ratio that is lower than 1:1. This means that the engine crankshaft rotates more times for each rotation of the output shaft. Typically, overdrive gears are the highest gears in a transmission.

The primary purpose of engaging the overdrive gear is to improve fuel efficiency and reduce engine wear. When a vehicle is traveling at a steady, high speed on a highway, the engine does not need to work as hard in an overdrive gear. This allows the engine to operate at lower revolutions per minute (RPM) for a given road speed, which in turn consumes less fuel. Additionally, lower engine RPMs result in less mechanical stress and heat generated within the engine, contributing to its longevity.

Many automatic transmissions have an overdrive gear that can be automatically engaged by the transmission's control system. Some manual transmissions also offer an overdrive gear. Often, there is a button or switch on the gear selector (for automatic transmissions) or the shift knob (for manual transmissions) that allows the driver to manually engage or disengage overdrive. Disengaging overdrive can be beneficial when extra power is needed for acceleration, climbing hills, or towing, as it allows the engine to reach higher RPMs more readily. The term "ylikierroksella" thus encapsulates this operational state of a vehicle's drivetrain.