How is car engine horsepower calculated?
2 Answers
Engine horsepower calculation: 1 kilowatt (kW) equals 1.36 horsepower. The following is a related introduction about horsepower: Introduction to horsepower: Horsepower is a commonly used unit of power measurement in engineering technology, which is a physical quantity to measure the maximum speed of a car. A higher horsepower means a higher maximum speed of the car. Torque is a physical quantity to measure the acceleration ability of a car. A higher torque means better acceleration performance, in other words, more power. Location of car horsepower labeling: Horsepower has been abolished in the national legal measurement units, but now cars use kilowatts to indicate power. Generally, the horsepower of a car can be found in the engine compartment, where there is a nameplate that indicates the weight, engine power, number of passengers allowed, etc.
When people ask me how engine horsepower is calculated, I always share my experience watching engineers test engines at the tuning shop. Simply put, horsepower is a unit of power, where 1 horsepower equals the ability to lift a 75kg weight 1 meter per minute. But in reality, it's measured using a dynamometer: the car is placed on rollers, the engine is run at full throttle, and the computer calculates the flywheel horsepower based on the roller resistance. During testing, the transmission must be in the highest gear, and it takes over ten minutes to get the results. I remember once testing a modified car, blue smoke was coming out of the engine bay, but the numbers shot up to 420 horsepower—the owner's mix of heartache and excitement was hilarious. This stuff is heavily affected by intake air temperature and altitude; horsepower naturally drops in high-altitude areas.
