Thread: Responsibilities of power and torque

 
Car engines are characterized by a number of parameters, important and unimportant, from the principle of the ignition mixture to aspects of wear, operating characteristics and fuel consumption. In this series a very important question presented main technical parameters power units, since they depend on high-quality machines.

The driver whose car is a means of intense movement, and not walking slow, primarily interested in the dynamics of acceleration and maximum speed. Depend on these characteristics from the two parameters of the engine power and torque, which in first approximation is defined as vzaimodeistvie.
Power is energy generated by the engine per unit time due to the combustion of fuel. But causes the car to move it and created it on the crankshaft torque, which is transmitted through the box on wheels. Power is the total moment produced by the engine within seconds, and torque is the torque at the time of its creation. The ratio of power by the time equal to the number of revolutions, which promoted the crankshaft at the moment.
It would seem, because the indicators are interrelated, there is no need to consider both. But the fact that they are not constants, and direct their dependence is observed only in a certain rpm range of the motor.
Power, which determines the speed of the machine, steadily increasing in proportion to the frequency of rotation of the shaft and soars to the peak at 5.5-6.5 thousand rpm In the passport of any car near maximum capacity necessarily spelled out the exact speed needed to achieve it.
Torque depends on the speed is not so clear, because a large part is spent on overcoming the resistance of the motor. The extreme values of the parameter is not at a maximum, and the average rotational speed of the crankshaft.
If there is a need to increase thrust, for example, when overtaking the success of the maneuver is not guaranteed only one high index of maximum power. To switch to high speed takes time, which is defined as the maximum torque and the speed at which it is achieved. These values are also documented recorded and appear in pairs.
The closer readings of the tachometer to the passport turnover, the faster accelerating car. If the current mode of motion is not enough stock of torque, it is necessary to switch to a lower gear to increase the gear ratio of the transmission. The unwinding of the shaft to the desired speed takes time, resulting in the acceleration slows down. Conversely, when the maximum torque is necessary at low revs, which makes the motor before the maneuver, it is enough to extenuate the gas pedal so that the machine will immediately gathered momentum.
Thus, in terms of speed the dominant role played by power and acceleration responds torque. Both options are equally important and must be considered when selecting the power unit.