Before revision: The West number may be defined as: where: Wn is the West number Wo is the power output of the engine (watts) P is the mean average gas pressure (Pa) or (MPa, if volume is in cm3) V is swept volume of the expansion space (m3) or (cm³, if pressure is in MPa) f is the engine cycle frequency (Hz) TH is the absolute temperature of the expansion space or heater (kelvin) TK is the absolute temperature of the compression space or cooler (kelvin) When the Beale number is known, but the West number is not known, it is possible to calculate it.
After revision: Bn is the Beale number for an engine operating between temperatures TH and TKThe West number may be defined as: where: Wn is the West number Wo is the power output of the engine (watts) P is the mean average gas pressure (Pa) or (MPa, if volume is in cm3) V is swept volume of the expansion space (m3) or (cm³, if pressure is in MPa) f is the engine cycle frequency (Hz) TH is the absolute temperature of the expansion space or heater (kelvin) TK is the absolute temperature of the compression space or cooler (kelvin) When the Beale number is known, but the West number is not known, it is possible to calculate it.