Diesel engine cycles
Combustion in diesel engines

To describe motor cycles, we use the following quantities, which allow us to compare motors without regard to their size.

Specific consumptionCS is the ratio of fuel consumption to power output. It is expressed in g/(kW · h) or in g/(hp · h). This notion can refer to the power actually available on the engine shaft, i.e. the effective specific consumptionCS_e , or to the power indicated as the indicated specific consumption CS _i.

Specific consumption does not take into account the calorific value of the fuel used, unlike efficiency, which represents the inverse ratio. With standard fuels, an efficiency of 50% corresponds to a specific consumption of around 170 g/(kW · h).

The specific fuel consumption of the best large engines...