Two technicians are discussing compression testing on a hybrid vehicle equipped with an Atkinson cycle engine. Technician A says the compression reading of an Atkinson cycle engine is normally higher than a conventional engine. Technician B says a scan tool may be needed to perform the compression test. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Question

Quizplus · Accepted Answer

Technician B is correct because, in modern vehicles, especially hybrids with Atkinson cycle engines, a scan tool may be required to properly perform a compression test due to the engine's advanced control systems. Technician A is incorrect because Atkinson cycle engines typically have lower compression readings than conventional engines due to their design, which allows the intake valve to stay open longer, effectively reducing compression ratio for efficiency gains.

Two Technicians Are Discussing Compression Testing on a Hybrid Vehicle