1. Combustion: The engine (typically an internal combustion engine) mixes fuel and air. A spark ignites this mixture, causing a rapid expansion of gases. This controlled explosion pushes pistons within the engine cylinders.
2. Mechanical Energy Conversion: The movement of the pistons is converted into rotational motion via a crankshaft. This rotational energy is the driving force of the car.
3. Transmission: The crankshaft's rotational energy is transferred to the transmission. The transmission modifies the rotational speed and torque (turning force) to suit different driving conditions (e.g., acceleration, cruising, hill climbing). Different gears provide varying ratios of speed to torque. Automatic transmissions do this automatically, while manual transmissions require the driver to select the gears.
4. Driveshaft: The transmission sends the rotational energy to the driveshaft (in rear-wheel-drive and all-wheel-drive cars). In front-wheel-drive cars, the transmission is directly connected to the wheels via axles.
5. Differential: The differential allows the wheels to rotate at different speeds, which is necessary when turning. Without a differential, the wheels would drag when turning.
6. Axles and Wheels: The driveshaft connects to the axles, which transfer the rotational energy to the wheels. The wheels, rolling against the road surface, provide the traction needed to propel the car forward.
7. Braking System: The braking system, independent of the propulsion system, uses friction to slow or stop the car's wheels.
In simpler terms: The engine explodes fuel to turn a spinning shaft. This spinning shaft turns the wheels, making the car move. The transmission helps to control how fast and powerfully the wheels turn.
