So I'm doing a thermo report on a diesel engine and can't for the life of me think of why volumetric efficiency changes with the engine at CONSTANT rpm and the only thing we are varying is fuel.
VE goes down as you increase fuel flow but then goes up a little bit at the end as you can see from the table below. Why does airflow change at all? I can't figure it out...I mean the fuel is injected just before the end of the compression stroke so the inlet valve has obviously closed ages ago for the beginning of compression and the cylinder has already ingested all the air it's going to see til the next cycle.
VE goes down as you increase fuel flow but then goes up a little bit at the end as you can see from the table below. Why does airflow change at all? I can't figure it out...I mean the fuel is injected just before the end of the compression stroke so the inlet valve has obviously closed ages ago for the beginning of compression and the cylinder has already ingested all the air it's going to see til the next cycle.

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