Honda’s Insight uses a 1.0
liter, 3-cylinder (58hp) gasoline engine to run the car. But the engine is underrated for
the car, and it wouldn’t have enough power for hill-climbing and acceleration if
that’s all that powered it. So Honda simply stuck a pancake motor on the flywheel
that kicks in for acceleration. High fuel economy comes mainly from using an underrated
engine and relying on the motor for peak power demands.
When a 150 hp engine is just cruising along at, say, 10 hp, which is all
you need to maintain cruising speed, fuel consumption per unit of output can double or
triple. A gasoline engine operates most efficiently at about 75 - 80 percent load.
That’s the region in which it delivers the most output per unit of fuel consumed.
