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Turn Over
Definition:
- Meaning: When an engine “turns over,” it refers to the action of the crankshaft rotating as a result of the starter motor’s operation.
- Process:
- Starter Motor: The starter motor engages with the engine’s flywheel or flexplate (depending on whether it’s a manual or automatic transmission) to rotate the crankshaft.
- Crankshaft Rotation: As the starter motor turns, it initiates the movement of the crankshaft.
- Piston Movement: The crankshaft’s rotation causes the pistons within the engine’s cylinders to move up and down.
- Combustion Initiation: This movement allows the engine to begin the combustion process, where air and fuel are mixed and ignited to produce power.
- Significance: “Turning over” is crucial because it starts the sequence of events necessary for the engine to generate power and run. Without the crankshaft turning, the engine cannot combust fuel, and therefore, the vehicle cannot move.
Key Points
- Starter Action: The starter motor engages the flywheel/flexplate teeth, rotating the crankshaft.
- Piston Movement: As the crankshaft turns, it moves the pistons up and down within their cylinders.
- Engine Activation: This action initiates the combustion process, allowing the engine to generate power.
Example Usage
- Scenario: When a driver turns the key (or presses a button) to start the engine, they are activating the starter motor. The engine is said to “turn over” once the crankshaft begins to rotate, indicating that the combustion cycle is starting.
In essence, “turn over” describes the initial rotation of the engine’s crankshaft by the starter motor, which is essential for starting the combustion process and powering the vehicle.
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