käivitusmootori

Käivitusmootor, also known as a starter motor, is an electric motor that is used to crank and rotate an internal combustion engine to initiate the engine's own combustion process. Once the engine starts, the starter motor is disengaged. The primary function of a käivitusmootor is to overcome the inertia of the stationary engine's crankshaft and pistons, as well as the resistance from compression within the cylinders, to bring it up to a speed where combustion can be sustained.

The käivitusmootor typically receives its power from the vehicle's battery. When the ignition key is turned or the start button is pressed, a signal is sent to the starter solenoid. This solenoid engages a small pinion gear (often called a Bendix drive) on the starter motor shaft with a larger gear on the engine's flywheel. Once engaged, the electric motor spins the pinion, which in turn rotates the flywheel and the crankshaft. After the engine starts and the driver releases the ignition, the solenoid retracts the pinion gear, and the starter motor stops. Various types of käivitusmootor exist, including direct-drive and offset-gear starters, each with its own design and efficiency characteristics.