Search results
Results From The WOW.Com Content Network
Engine power is the power that an engine can put out. It can be expressed in power units, most commonly kilowatt, pferdestärke (metric horsepower), or horsepower.In terms of internal combustion engines, the engine power usually describes the rated power, which is a power output that the engine can maintain over a long period of time according to a certain testing method, for example ISO 1585.
Taxable horsepower does not reflect developed horsepower; rather, it is a calculated figure based on the engine's bore size, number of cylinders, and a (now archaic) presumption of engine efficiency. As new engines were designed with ever-increasing efficiency, it was no longer a useful measure, but was kept in use by UK regulations, which used ...
A typical turbocharged V8 diesel engine might have an engine power of 250 kW (340 hp) and a mass of 380 kg (840 lb), [1] giving it a power-to-weight ratio of 0.65 kW/kg (0.40 hp/lb). Examples of high power-to-weight ratios can often be found in turbines. This is because of their ability to operate at very high speeds.
In 1986 Ticino switched to a system based on a calculation including engine size and weight. [24] The tax horsepower system remained in effect for seven cantons long into the 21st century; however, as of 2022, although quite likely earlier, Geneva was the only canton to still base road tax purely on tax horsepower. [25]
where is propulsive efficiency (typically 0.65 for wooden propellers, 0.75 metal fixed pitch and up to 0.85 for constant-speed propellers), hp is the engine's shaft horsepower, and is true airspeed in feet per second, weight is in lbs.
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 ...
Specific output is a measure of internal combustion engine performance. It describes the efficiency of an engine in terms of the brake horsepower it outputs relative to its displacement. The measure enables the comparison of differently sized engines, and is usually expressed as kilowatts or horsepower per litre or per cubic inch. [1]
Mean effective pressure is also useful for initial design calculations; that is, given a torque, standard MEP values can be used to estimate the required engine displacement. However, mean effective pressure does not reflect the actual pressures inside an individual combustion chamber – although the two are certainly related – and serves ...