What is the Difference Between Power and Horsepower in Cars?
4 Answers
The differences between car power and horsepower mainly include the following points: 1. Different meanings. (1) Engine power refers to how fast the engine does work. The work done by the engine per unit time is called the engine's power. Corresponding to indicated work and effective work, it is called indicated power and effective power (output power), respectively. The difference between these two is called mechanical loss power. (2) Horsepower was proposed by James Watt and is a commonly used unit of power in engineering. It generally refers to metric horsepower rather than imperial horsepower. 2. Different physical meanings. (1) Power: A physical quantity that represents how fast an object does work. (2) Horsepower: It is defined that 1 metric horsepower is the work done to lift 75 kilograms-force·meters in 1 second. 3. Conversion relationships. (1) 1 kilowatt (kW) = 1.3410221 imperial horsepower (hp). (2) 1 kilowatt (kW) = 1.3596216 metric horsepower (ps). (3) 1 imperial horsepower (hp) = 1.0138697 metric horsepower (ps). 4. Different usage habits. Europe and America are accustomed to using horsepower as the unit, while China is accustomed to using metric units, which is kilowatts.
I also couldn't understand the difference between power and horsepower before buying a car, but later figured it out by studying engine parameters. Power is a physics concept with the international unit of kilowatts, measuring how much energy the engine can output per second. Horsepower is actually a special unit of power, just like the relationship between kilometers and miles. The automotive industry is accustomed to using horsepower to indicate power output, especially German cars using PS (metric horsepower) and American cars using HP (imperial horsepower). A 180-horsepower car is equivalent to 132 kilowatts of power. So next time you look at specifications, you'll understand that horsepower and kilowatts are just different expressions of the same performance.
A veteran driver with over a decade of experience tells you: Power is a serious technical specification, while horsepower is what we commonly refer to as 'how much strength it has.' Mechanics use power to measure engine performance during repairs, but among car enthusiasts, we say 'this car has 200 horsepower.' The conversion is straightforward: 1 horsepower is approximately 735 watts. My own car, rated at 155 horsepower, is equivalent to 114 kilowatts. Remember one thing: the horsepower figures advertised by manufacturers are essentially converted power values, just expressed in units we're more accustomed to, to show how much strength the engine really has.
I discussed this topic with an engineer at the auto show last time. Simply put, power is a scientific unit (kilowatts), while horsepower is a conventional term in the automotive industry. It's like measuring body weight in kilograms or pounds - they essentially represent the same thing. One metric horsepower is approximately equal to 0.735 kilowatts. For example, the BMW 320's 184 horsepower actually translates to 135 kilowatts. Note that different countries use different horsepower units: Germany commonly uses PS, while the UK uses HP, with slight numerical variations. When checking car specifications, don't get confused - both numbers indicate the engine's power level.
