The C has a much smaller engine. If a hypermiling driver drove 45-55mph, would the C be able to beat the standard prius in fuel economy?
There's more at work than the engine size. The c also has a smaller battery and a less slippery shape. That being said, it's possible. The engine in the c is the same size as was used in the Gen 2 standard Prius.
One of the reasons Toyota upped the engine size to 1.8L was to reduce the engine RPM's at highway speed to improve highway MPG's.
Got it. Just seems odd that making the engine bigger would increase fuel economy. Normally you think "make the engine smaller, less cylinders, less moving mass" in order get better efficiency. All the highest MPG cars in Europe are tiny three-cylinder versions. (The highest being the Lupo TDI at 80mpg and only 1.2 liter.)
What the HSD excels at is utilizing the engine as much as possible in optimal conditions (minimum engine speed with low manifod vacuum/high loading). At higher speeds the power needed can't be met by a smaller engine without speeding the engine up to the point of much less efficiency. With its lighter vehicle weight the c's engine/traction motor/battery sizing work very well at "city" speeds. At highway speeds it works well but not as efficiently because of the power needed to push it through the air.
Good point. I guess it also helps that the G3 has no belt-driven accessories dragging on it, like the C and previus G2 had. In one youtube review a guy asked, "Why didn't they put the 1.8L engine in the Prius c? That was the original plan but apparently Toyota changed their minds." Anyone know why that happened?
In general the c has better fuel efficiency off the freeway so if you avoid high speeds then you should beat the Prius easily.
