π Key Concepts
β’ Review the theoretical diesel cycle PβV diagram and what each numbered point represents (intake, compression, combustion, expansion, exhaust).
β’ Recall that in the ideal diesel cycle, fuel is added so that heat is supplied at constant pressure, and then the gases do work on the piston.
β’ Look at how volume and pressure change between points "3" and "4" on the curve in the illustration.
π Think About
β’ From point "3" to point "4", is the piston moving toward or away from top dead center (is cylinder volume increasing or decreasing)?
β’ If volume is changing but pressure is mostly falling, which process in a diesel engine stroke does that best represent: compression, combustion at constant something, or power/expansion?
β’ In the ideal diesel cycle, which segment (1β2, 2β3, 3β4, or 4β1) is associated with the power stroke where the hot gases push the piston down?
β
Before You Answer
β’ Check whether volume increases or decreases between points "3" and "4" on the PβV diagram.
β’ Confirm whether pressure is roughly constant or clearly changing along the 3β4 curve.
β’ Match that PβV behavior to the textbook description of compression, constant-pressure combustion, constant-volume combustion, or expansion in the ideal diesel cycle.