| makes it less dense for a given volume unit. The ECU's fuel programming is all based upon injector pulse width (time) and injector flow rate (volume per time) so the fuel delivery to the engine is oblivious to density (mass) and is strictly volume based - which is unfortunate since any stoichiometric reaction is 100% mass based. The PRVR system attempts to crutch this situation by temporarily raising the fuel pressure by switching the FPR's vacuum reference from manifold to atmospheric. But I believe this is just an "on/off" system and it can not modulate the fuel pressure with varying fuel temps. I've logged fuel rail temp a lot and found during normal operating conditions it can run anywhere between 120° to 180°F depending upon ambient temp, highway vs stop and go driving, and amount of fuel in the gas tank. In a hot start situation where the engine has heat-soaked for 5 or more minutes, fuel temp easily goes above 200°F and it takes about 2 minutes for the temp to come back down to where it was before turning the engine off.
|
15:21:46 01/02/23
