A Study of Engine Breathing Characteristics

A nondimensional representation for a four stroke spark ignition engine was obtained that included the transient charging and exhaust effects. Two basic advantages accrued from this approach; the design and operating parameters that evolved from the nondimensional approach are truly basic in nature, which makes the computer solution more universally applicable to all engines. The inclusion of the transient effects made the representation more realistic and of particular value in the study of engine breathing problems. The effect of valve timing, cam design, valve dimensions, and inlet temperature on engine performance were studied with the computer model.