Understanding your car engine: Motor power explained

When auto manufacturers advertise their cars, we are bombarded with various numbers ranging from horsepower to cubic centimetres. Have you ever given attention to what those numbers are telling us? Does bigger mean better? What is PS or bhp or hp? What is Nm? What is torque? There are a whole lot of questions that plague us.

Here are clear and compact answers to those.

What is horsepower (HP)

The concept of horsepower goes back to 18th century Scotland and inventor James Watt. He was trying to compare the power of horses' with the power of steam engines that were gradually replacing them. He calculated One hp was the equivalent of one horse lifting 33,000 pounds over one foot in one minute on the surface of the Earth. In a car, hp describes the total amount of power an engine can produce. The higher the hp, the more power the car has, so the faster the top speed.

What is Pferdstarke (PS)

PS is a common engine measurement. This stands for the German word Pferdstarke which means horse strength. This comes as an attempt to make hp metric. In this measurement system, one PS equals 98.6 per cent of one hp.

What is brake horsepower (bhp)

Brake horsepower or bhp is often used as a very realistic measurement of power. This is because bhp considers the power left after other car parts are working, such as the gearbox, alternator, and water pump, as well as any loss of power due to friction.

What is torque?

In the specification sheets of vehicles, one force is often quoted alongside the power output figures, which is torque. The torque is usually measured in either pound-feet (lb-ft) or Newton metres (Nm). The torque measures the amount of force that is required to twist an object. When it comes to vehicles, it is the amount of twisting force available at the crankshaft. The more torque a vehicle has, the more pulling power its engine has. This is the force one feels when accelerating. The torque indicates how fast the engine can move the car's weight. The more torque there is, the more acceleration there will be.