[drquine]

My understanding is that pollution reducing catalytic converters need to come up to high temperature as quickly as possible and remain hot to be effective. How does a hybrid / PHEV accomplish that if the engine is only used intermittently and keeps turning off?

[bwilson4web]

In the case of my 2003 Prius, it runs the engine for about 45 seconds until the O{2} sensors are operational and this lights off the catalytic converters. There after, the intermittent engine operation keeps the cats hot. There is not enough heat loss to disable them as long as the engine runs from time to time.

Bob Wilson

[FastMover]

Sometimes, in very cold conditions here in Washington State, it would seem that the ICE comes on in my TCH without any reason when standing at a stoplight or in low speed EV between traffic lights. The battery has a good SOC and power demand is not sufficient for an engine start. I suspect the reason is the catalytic converter temperature as I usually have the environmental system in ECO mode.

[bwilson4web]

What I found is when temps are under 40F and winds are high, the ICE can cool enough that it has to run to boost the coolant temperature up. Just a though.

Bob Wilson