An indicator trace is taken from a single-cylinder four-stroke petrol engine of swept…
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 trace is taken from a single-cylinder four-stroke petrol engine of swept volume 0.35 litre running at 4800 revolutions per minute, so that the cylinder completes one cycle every two revolutions. The trace shows two loops:a large clockwise loop with rounded corners and a sloping burn line, of mean height 4.2×105Pa over the swept volume (mean height = enclosed area / swept volume);below it a small anticlockwise pumping loop, drawn during the exhaust and intake strokes, enclosing 12J.
((a)) Find the net work delivered per cycle by the gas on the piston.
((b)) Find the power this trace corresponds to.
((c)) The trace is now redrawn as the air-standard Otto cycle on the same axes. List three features of the measured trace that the air-standard idealisation removes, and state for each which way it pushes the computed efficiency.