What's the difference between power and torque of a car ?

Can anybody explain the terms "power" and "torque" in common man's language ? Whats the difference ? While the term "power" is quite understandable , "torque" is something not common in daily life. I know the definition found in any physics book, but how does it apply in a car engine ? And does the "rpm" term has got any significance while we talk about "power" of  an engine ? For example, for UVA LS the power is 76hp@5500 rpm and torque 110Nm@4400rpm and for Getz 1.1GVS the power is 66hp@5500 rpm and torque is 102Nm@3200rpm . What does that mean ?

Power is the rate at which work is done, that is the rate at which energy is transferred by force. The rotational force that is generated by the engine (by which the energy is trasferred) is called torque.

RPM is the short for "rotation per minute". This is the speed at which the engine is rotating the flywheel.

Internal combustion (IC) engines do not produce same power at all engine speeds, hence there would be an engine speed (RPM) at which the engine would be generating max power. Same is the case with torque.

As a characterisitc of IC engine the max torque is normally produced at a lesser engine speed than when the max power is.

In short and sweet Power means the Engine Speed and Power and Toque means the rate of Pick up (correct me if i am wrong)

WOW....thanks guys for all the info....

Narayana,

That's well explained.  Welcome to CarWale & hope to see you participating on other threads as well.

Honesty is not a Spare Wheel that you pull out when in trouble. It's a Steering Wheel that keeps you on the right path throughout the life's journey.

in much simpler terms..

power is the amount of energy tht the engine can transfer with respect to time... (thts wer u get ur pickup from)

torque is the load carryin capacity..

so it depends on ur need... the more acceleration u want,, the more power u need... whereas, incase u need to carry load around u need more torque..

the rpm indicates at what rpm the engine can deliver the max power/torque..

petrol cars are famous for their power, whereas diesel for their torque.

Thanks a lot , everybody...........now i can say i am almost clear.........

Let me try not to be too technical, and try to make sense of the above:
For accelarating you need both power and torque. In simple terms, torque is the rate at which an engine can produce power. Remember, accelaration is the rate at which speed changes, so to maintain a speed you need power to overcome the resistance (road & air friction and in the moving parts of the car as well). Normally, the RPM between the max torque and max power is the power band of the car, lower end of this band is where you would be crusing, and higher end is where you are racing
Guys, correct me if I am wrong!
Thanks
Narayana

there is actually a difference?

i was under the impression power is the more 'indian' word for torque.

hehe.

Akheel, there's always a first time to everything - even Narayan & Nic must have learned about the difference for the first time sometime.


Honesty is not a Spare Wheel that you pull out when in trouble. It's a Steering Wheel that keeps you on the right path throughout the life's journey.