When a car “turns over,” it typically means that the engine is starting and running. In other words, the car is going from a stationary state to an active state where the engine is running, and the wheels are ready to move the vehicle.
The process of a car turning over starts with the ignition system. When you turn the key in the ignition or press the start button in modern cars, it sends an electrical signal to the starter motor. The starter motor is responsible for cranking the engine, which means it spins the engine’s crankshaft, causing the pistons to move up and down. This movement creates the necessary pressure for the engine to start.
To better understand the process, let’s break it down step by step:
1. Key in the ignition: When you turn the key or press the start button, it activates the ignition switch, which sends an electrical signal to the starter motor.
2. Starter motor engagement: The starter motor engages with the flywheel or flexplate, which is attached to the engine’s crankshaft. The flywheel or flexplate has teeth on its edge, and the starter motor has a gear that meshes with these teeth.
3. Cranking the engine: Once engaged, the starter motor spins the flywheel or flexplate, causing the crankshaft to rotate. This movement creates the necessary motion for the engine to start.
4. Fuel and spark: While the engine is cranking, the fuel injectors spray fuel into the combustion chambers, and the spark plugs generate sparks. This combination of fuel and spark starts the combustion process.
5. Combustion and compression: The fuel and spark ignite, creating small explosions inside the cylinders. These explosions push the pistons down and create rotational force on the crankshaft. Simultaneously, the other pistons are moving back up, compressing the air-fuel mixture for the next combustion cycle.
6. Engine running: As the crankshaft continues to spin, the engine gains momentum, and the cylinders keep firing in the correct order. The continuous combustion cycles generate power and allow the engine to idle and keep running.
If the car fails to turn over, it could indicate various issues:
1. Weak battery: If the battery doesn’t have enough power, it may not provide sufficient electricity to start the car. This can be due to a discharged battery or a faulty alternator that fails to charge the battery properly.
2. Starter motor issues: The starter motor may have a weak or worn-out component that prevents it from cranking the engine. It could be a faulty solenoid, motor brushes, or a malfunctioning gear mechanism.
3. Ignition system problems: Issues with the ignition switch, ignition coil, spark plugs, or fuel injectors can prevent the engine from starting. Without a reliable spark or proper fuel delivery, the combustion process won’t initiate.
4. Engine or mechanical failures: More severe issues, such as a malfunctioning fuel pump, a broken timing belt, or a seized engine, can also prevent the car from turning over. These problems typically require professional repair or replacement.
In summary, when a car “turns over,” it means that the engine is starting and running. The process involves the ignition system sending an electrical signal to the starter motor, which cranks the engine by spinning the crankshaft. Fuel and spark are then provided, leading to combustion, compression, and the engine running. If the car fails to turn over, it may indicate issues with the battery, starter motor, ignition system, or more severe mechanical failures.
