I bought my 2008 Camry Hybrid brand new from a U.S. dealer. It gives me 800 km per tank of gas in summer but that drops to just under 650 km per tank in the winter months (Added: I put 51 litres in when I fill up). I get it serviced by a Toyota dealer, and he can't find any problems. I don't understand why the fuel economy is so much worse in the winter. – Daniel, Calgary
The trouble with a hybrid is that when it's cold outside, passengers – and batteries – like it warm.
"Hybrids get notably lower mileage in the winter, due to reduced battery performance and greater use of power-sapping heating," writes John Voelcker at Green Car Reports.
First, a very basic refresher on hybrids. Hybrids use two powertrains, an electric motor and a gasoline engine. Your 2008 Camry has a 2.4-litre four-cylinder engine and a permanent magnet synchronous motor. The electric motor is powered by the nickel metal hydride battery. Regenerative brakes give power back to the battery.
But here's the trouble, batteries are sluggish when they're really cold – like when your car is parked outside in the middle of a Calgary winter. The chemical reaction that generates electricity is slowed down, so they don't give you power, or recharge, as quickly.
With less power available from the battery, the car has to rely on the internal combustion engine more. The engine uses gas, thus, lower gas mileage.
It's the same with the heater in the passenger compartment. Some hybrids have an additional electric heater, which uses up battery power. When juice getting used by accessories is more than the battery can deliver without being drained, the engine kicks in.
But, even with that extra electric heater, the heater still works like any car heater. The heat comes from the hot engine coolant circulating through the heat exchanger in the dash. If the heat is on high, the engine needs to run more often.
Toyota Canada's Canadian specs say the 2008 Camry Hybrid gets 5.7 litres/100 km.
Sandy Di Felice from Toyota replied in an e-mail that other factors "including winter fuel formulations, the installation of winter tires, changes in tire pressures, driving through higher resistance snow & slush, greater friction in fluids (transmission fluids, engine oils etc), colder and more dense air" can all impact fuel economy.
Based on your regular 51-litre fill ups, your car's fuel economy is approximately 6.4 litres/100 km in the summer and 7.8 litres/100 km in the winter. The Automotive Protection Association (APA) says the U.S. fuel economy numbers for all vehicles are closer to what you'll actually see, compared to the Canadian numbers. The Environmental Protection Agency gave the 2008 Camry 34 mpg (combined city and highway) -- that's 6.9 litres/100 km.
Fuel economy results can vary due to driving behaviour, the condition of the car, climate and terrain. Higher speeds and aggressive driving can all take a toll on fuel economy. By driving smoothly and avoiding sudden starts and stops as much as possible, you may be able to go longer between fill ups.
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Correction: Our reader's fuel economy ratings have been changed. They are now based on his record of 800 km of driving in the summer vs. 650 km in the winter, on a 51-litre fill up each time.