An indicator is fitted to one cylinder of a compression-ignition engine
PHYSICS · Multi-part · Fermi University Physics · Thermal, Statistical & Complex Systems · The laws of thermodynamics · The laws of thermodynamics
Thermal Physics, Ch Internal-combustion cycles and indicator diagrams
Problem
An indicator is fitted to one cylinder of a compression-ignition engine. Over one cycle the pen traces a single closed loop, clockwise on the p-V diagram. The loop spans the swept volume 0.40 litres and has a mean height (mean effective pressure) of 6.0×105Pa.
((a)) Find the net work delivered by the gas per cycle.
((b)) The same cylinder is modelled by an air-standard Diesel cycle: a fixed mass of ideal gas with constant γ=1.40, run quasistatically round a closed loop, with the burn replaced by heat added at constant pressure and the exhaust by heat removed at constant volume, and with friction and heat leaks removed. The compression ratio is r=V1/V2=18 and the cut-off ratio is ρ=V3/V2=2.0. Find the efficiency of this idealised cycle.