Title.
When a car has its engine on, the engine is working. But if its in park, the car doesn’t move. How? The engine is still running like if the car was driving, but what mechanism prevents the car from moving?
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On an automatic car, once you shift into park or neutral, every clutch inside the transmission disconnects, so the engine/flywheel/torque converter output shaft turns nothing. Plus the parking pawl locks the output shaft of the transmission to prevent the car from moving.
For stopping at a red light shifted into Drive, the transmission is in gear so any transmission input shaft rotation will result in car rolling forward. At this time the slipping part is the “torque converter” upstream of the transmission.
Torque converter takes the role of the foot operated clutch and lower gear ratios on an automatic car. If you hold the car still while in gear, the converter slips so the engine can keep turning without moving the car even if you are in gear.
On older generation cars, the TC is always slipping because it’s a fluid coupling. This creates heat and fuel efficiency problems. Newer cars will lock up the TC once you are speeding up eliminating this friction loss.
On an automatic car, once you shift into park or neutral, every clutch inside the transmission disconnects, so the engine/flywheel/torque converter output shaft turns nothing. Plus the parking pawl locks the output shaft of the transmission to prevent the car from moving.
For stopping at a red light shifted into Drive, the transmission is in gear so any transmission input shaft rotation will result in car rolling forward. At this time the slipping part is the “torque converter” upstream of the transmission.
Torque converter takes the role of the foot operated clutch and lower gear ratios on an automatic car. If you hold the car still while in gear, the converter slips so the engine can keep turning without moving the car even if you are in gear.
On older generation cars, the TC is always slipping because it’s a fluid coupling. This creates heat and fuel efficiency problems. Newer cars will lock up the TC once you are speeding up eliminating this friction loss.
A car has a “transmission”, something between the engine and wheels that uses a system of gears to change how fast the engine is trying to spin the wheels. When you shift into park, the transmission disconnects from the wheels altogether. It also drops a little pin into the linkage on the wheel side of things, so the car won’t even roll on its own from gravity on a gentle incline. Mind you, you should always use the parking brake when you park, for peace of mind against that little pin failing – that can happen on a less gentle incline, or if someone crashes into your car.
A car has a “transmission”, something between the engine and wheels that uses a system of gears to change how fast the engine is trying to spin the wheels. When you shift into park, the transmission disconnects from the wheels altogether. It also drops a little pin into the linkage on the wheel side of things, so the car won’t even roll on its own from gravity on a gentle incline. Mind you, you should always use the parking brake when you park, for peace of mind against that little pin failing – that can happen on a less gentle incline, or if someone crashes into your car.
A car has a “transmission”, something between the engine and wheels that uses a system of gears to change how fast the engine is trying to spin the wheels. When you shift into park, the transmission disconnects from the wheels altogether. It also drops a little pin into the linkage on the wheel side of things, so the car won’t even roll on its own from gravity on a gentle incline. Mind you, you should always use the parking brake when you park, for peace of mind against that little pin failing – that can happen on a less gentle incline, or if someone crashes into your car.
#ELI5
Take the chain off your bicycle.
Now pedal as fast as you can.
Your “engine” is working, but you’re not going anywhere. Why?
There’s a part that takes the energy you make, and sends it to the back wheel. That part (the chain) is disconnected, or gone in this example.
In a car, it’s the same thing. There’s a part (called the transmission) that takes the energy from the engine, and sends it to the wheels.
The transmission can be “disengaged” so that there’s no energy going from the engine to the wheels. Pretend it’s like taking the chain off your bicycle.
#ELI5
Take the chain off your bicycle.
Now pedal as fast as you can.
Your “engine” is working, but you’re not going anywhere. Why?
There’s a part that takes the energy you make, and sends it to the back wheel. That part (the chain) is disconnected, or gone in this example.
In a car, it’s the same thing. There’s a part (called the transmission) that takes the energy from the engine, and sends it to the wheels.
The transmission can be “disengaged” so that there’s no energy going from the engine to the wheels. Pretend it’s like taking the chain off your bicycle.
#ELI5
Take the chain off your bicycle.
Now pedal as fast as you can.
Your “engine” is working, but you’re not going anywhere. Why?
There’s a part that takes the energy you make, and sends it to the back wheel. That part (the chain) is disconnected, or gone in this example.
In a car, it’s the same thing. There’s a part (called the transmission) that takes the energy from the engine, and sends it to the wheels.
The transmission can be “disengaged” so that there’s no energy going from the engine to the wheels. Pretend it’s like taking the chain off your bicycle.
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