Hybrid engines produce about ~20% more waste heat than the diesel engines. That's why hybrid drivers are warmer.

troy

Strictly speaking, I'm not entirely sure that's true.
Isn't the amount of waste heat generated determined by the thermal efficiency of the engine? Generally it's true that diesels have a higher thermal efficiency than gasoline engines, but the HSD gasoline ICE runs at higher efficiency than most gas ICEs, optimally up to 37%. While some industrial, stationary diesels achieve amazing thermal efficiency (see this recent post: http://www.greenhybrid.com/discuss/w...-ice.2391.html ), a car diesel has similar problems to a gas ICE in a car, that most often it is run at partial loads and thus under optimal thermal efficiency. I therefore wonder if the gas ICE in the HSD does not on average achieve a thermal efficiency to that of a diesel ICE in a car?

I think the Prius uses an electric heater, like the kind you can get for your home that plug in. I don't think the electricity is heating the coolant because this would be incredibly slow and inneffective in providing the initial heat that was desired. A Prius has a powerful DC-DC converter that propagates up to 100A of 12v power as needed from the large battery when running, so when your Prius first starts the heat is coming from the large battery until the ICE is warmed up, and like people have mentioned earlier it does this a lot faster than most cars because of the pollution controls needing to be at an optimal temperature.

2001 Prius Photos       2005 Prius Photos
1992 Mitsubishi Delica Diesel-WVO Hybrid Photos

Sure it is. With all other things being equal, the diesel engine has a higher thermal efficiency than a gasoline engine (no throttle/higher compression/more complete combustion), and will generate less waste heat.

Prius = 37% (according to you), but a highly efficient diesel, like those found in Polos, will achieve 47% efficiency. Crunch the numbers, and that equates to the Prius generating ~20% more waste heat.

troy