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Brake horsepower per cubic centimeter or (bhp/cc) is a figure of merit that is used to indicate the 'state of tune' of an internal combustion engine. It is defined as the ratio of the engine's net power output to its displacement, the internal size. Power is measured at its rated speed and full throttle.
Brake horsepower (bhp) is the power measured using a brake type (load) dynamometer at a specified location, such as the crankshaft, output shaft of the transmission, rear axle or rear wheels. [ 30 ] In Europe, the DIN 70020 standard tests the engine fitted with all ancillaries and the exhaust system as used in the car.
To calculate the actual efficiency of an engine requires the energy density of the fuel being used. Different fuels have different energy densities defined by the fuel's heating value. The lower heating value (LHV) is used for internal-combustion-engine-efficiency calculations because the heat at temperatures below 150 °C (300 °F) cannot be ...
The Prony brake is a simple device invented by Gaspard de Prony in 1821 to measure the torque produced by an engine. The term "brake horsepower" is one measurement of power derived from this method of measuring torque. (Power is calculated by multiplying torque by rotational speed.) [1]
Unlike most other systems, power is calculated by factoring flow volume (calculated from pump design specifications), hydraulic pressure, and RPM. Brake HP, whether figured with pressure, volume, and RPM, or with a different load cell-type brake dyno, should produce essentially identical power figures.
It is an administrative unit originally calculated partly from the power of the engine and used to calculate the amount of tax that may be due at the time of registration. The Citroën 2CV (two tax horsepower) was the car that kept such a name for the longest time. Its use in France dates from 1 January 1913.
However, it is the power a car can produce at the wheels (wheel horsepower or whp) that matters when it comes to acceleration performance. Wheel horsepower equals brake horsepower minus drivetrain losses, which can be anywhere from about 10% to 25%. [12] Power-to-weight ratio: hp/lb hp/lb W/kg acceleration higher is better Propulsive efficiency
Brake mean effective pressure (BMEP) is calculated from measured dynamometer torque. Net indicated mean effective pressure (IMEP) is calculated using the indicated power; i.e., the pressure volume integral in the work per cycle equation. Sometimes the term FMEP (friction mean effective pressure) is used as an indicator of the mean effective ...