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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 pressure lost to friction (or friction torque) and is just the difference between IMEP ...
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 ...
A consumption map or efficiency map [1] is a chart that displays the brake-specific fuel consumption of an internal combustion engine at a given rotational speed and mean effective pressure, in grams per kilowatt-hour (g/kWh). The map contains each possible condition combining rotational speed and mean effective pressure.
Compressibility factor values are usually obtained by calculation from equations of state (EOS), such as the virial equation which take compound-specific empirical constants as input. For a gas that is a mixture of two or more pure gases (air or natural gas, for example), the gas composition must be known before compressibility can be calculated.
Isotherms of an ideal gas for different temperatures. The curved lines are rectangular hyperbolae of the form y = a/x. They represent the relationship between pressure (on the vertical axis) and volume (on the horizontal axis) for an ideal gas at different temperatures: lines that are farther away from the origin (that is, lines that are nearer to the top right-hand corner of the diagram ...
The efficiency of internal combustion engines depends on several factors, the most important of which is the expansion ratio. For any heat engine the work which can be extracted from it is proportional to the difference between the starting pressure and the ending pressure during the expansion phase. Hence, increasing the starting pressure is ...
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British Railway Class 90 infobox showing brake force Brake force to weight ratio of the Class 67 is higher than some other locomotives. In the case of railways, it is important that staff are aware of the brake force of a train so sufficient brake power will be available to bring the train to a halt within the required distance from a given speed.