Fuel Efficiency
Why do HVs get worse fuel efficiency in winter than in other seasons?
Q. Why do HVs get worse fuel efficiency in winter than in other seasons?
A. Because the HV needs more fuel to warm up the engine and to run the heater in winter, fuel efficiency tends to be worse than in other seasons.
A fuel efficiency comparison by season is shown below. During winter, the HV needs more fuel to warm up the engine and to run the heater, causing fuel efficiency to drop. (The engine coolant is the heat source of the heater.)
The fuel efficiency of conventional vehicles worsens in summer due to the A/C, while the fuel efficiency of Toyota HVs worsens in winter more than summer because of the electric compressor which contributes to longer operation of the engine for heating in winter.
As a way to improve fuel efficiency in winter, the new model Prius incorporates an exhaust heat re-circulation system, which warms up the engine coolant using the engine exhaust heat.
- Example fuel efficiency comparison by season (reference)
- Exhaust heat recirculation system (ZVW30)
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