Quote:
Originally Posted by MetroMPG
With all the other tricks Toyota has thrown at squeezing ever more efficiency from the Prius, I'm a little surprised they don't have some kind of vane in the intake to pull cold OR warm air depending on power demand.
Or maybe there's too much thermal inertia to make that approach responsive enough when the driver calls for "FULL STEAM AHEAD" from the engine room?
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I suspect that it's complicated, between a winter cold start and summer restart, cold catalytic converter, and fully-warmed.
The Atkinson-cycle isn't known for torque, and if the CPU sees the throttle position sensor calling for wide open throttle, the motor assist is going to kick in, contributing it's torque and power, all the way up to the governed top speed.
In a winter scenario, where a heat-riser might be helpful, once the exhaust has some heat in it, and the intake tract is at a higher temp than ambient, on a call for more power, it may not be that much of a liability, since the electric motor is always at 100% available torque.
The CPU will always know the air mass, and ROM look-up tables will dial in the direct injection to optimize air-fuel ratio, plus ignition and valve timing, for best performance under the full spectrum of design conditions.
Ya just gotta love the integrated circuit and sensor technology.