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Old 02-09-2022, 07:50 PM   #7 (permalink)
Isaac Zachary
High Altitude Hybrid
Join Date: Dec 2020
Location: Gunnison, CO
Posts: 1,351

Avalon - '13 Toyota Avalon HV
90 day: 40.45 mpg (US)

Prius - '06 Toyota Prius
Thanks: 726
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My hybrids have lots of problems with the cold, mainly, they are too efficient. The engine must run terribly retarded to burn more fuel and heat up the engine quicker. Block heaters help, but I need to get higher powered ones put on the cars than the stock ones that barely keep the engine in the 30's (Fahrenheit) when it's below zero.

Something I've always wanted to do is add a heat exchanger on the exhaust like with the gen 3 Prii to warm things up quicker. (I'd also like to add some sort of HV battery heater as the NiMH batteries don't have any, but that doesn't apply to this thread). I'm also interested in wrapping the exhaust with insulation so the catalytic converters heat up quicker and stay that way. Of course keeping them from overheating in the summer would be a concern, but maybe that can be dealt with via water injection or something similar.

Anyhow, those are my observations with modern hybrids. If you can heat the engine, the catalytic converter and maybe perhaps the HV battery (if needed) you can get summer-like fuel mileage in theory. But what would be the most efficient and cost-effective way to do that?
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