The rotating or turning effort of the that range, torque is no longer increased. engine’s crankshaft is called engine torque. Engine torque is measured in foot-pounds ( ft.-lbs. ) or the metric measurement Newton-meters (N-m). engine produce a maximum amount of torque when operating within a narrow range of engine speeds. When an engine reaches the maximum speed within
The amount of torque produced in relation to engine speed is called the engine’s torque curve. Ideally, the engine should always be run when it is providing a maximum amount of torque. This allows the engine to provide the required amount of power while using a minimum amount of fuel.
As a car is climbing up steep hill, its driving wheels slow down because of the increased amount of work it must do; this causes engine speed to decrease as well as a reduce the engine’s torque. The driver must downshift the transmission or press down harder on gas pedal, which increases engine speed and allows the engine to produce more torque. When the car reaches the top of the hill and begins to go down, its speed and the speed of the engine rapidly increase. The driver can now up shift or let up on the gas pedal, which allows the engine’s speed to decrease and places it back into its peak within the torque curve.
Measurements of horsepower indicate the amount of work being performed and the rate at which it being done. The drive line transmit power and multiply torque, but it cannot multiply power. When power flows through one gear to another, the torque is multiplied in proportion to the different gear sizes. Torque is multiplied, but the power remains the same, as the torque is multiplied at the expense of rotational speed. Maximum horsepower occurs when the engine is operating at high speed and producing close to its maximum torque. Engine horsepower can be calculated by using a mathematical formula :
Hp = T X rpm / 5252
Where hp = horsepower; T= the amount of torque produced by an engine, rpm = the speed of the engine when it is producing the torque, and 5252 being a mathematical constant.