How Hybrid Cars Work

It's no secret that today's hybrid electric vehicles are able to achieve some remarkable fuel economy performance. In fact, the three highest-ranking vehicles in the latest EPA fuel economy ratings are hybrid cars, with the Honda Insight leading the way with an impressive 68 miles-per-gallon highway figure.

How do these hybrids deliver such improved performance? The answer is really quite simple...

Historically, automobiles have been powered by engines designed to handle a wide variety of driving situations. This now includes low output driving such as casual driving for going to work or running up to the grocery store. There is also the type of driving that involves climbinb a steep hill or accelerating quickly to merge into traffic. A vehicle must be designed to deliver enough power to handle the requirements of all types of driving situations.

This leads to cars being fitted with engines much more powerful than they need to be for average driving. Providing for all possible needs leads to inefficiency. If all other aspects are considered equal, smaller engines are generally more fuel efficient than larger ones, sometimes significantly so. Hybrid vehicles solve this dilemma in a variety of ways by utilizing smaller combustion engines and supplemental power for optimized efficiency.

The Honda Insight hybrid vehicle debuted with a three cylinder, 1.0 liter combustion engine for normal driving needs, and a 10 kilowatt, 13 horsepower alectric engine for supplemental power in demanding situations. The two engines combine to provide 67 horsepower, certainly not a high output, but adequate to safely handle all driving needs. Honda followed this up with a Civic hybrid which employs a 4 cylinder, 1.3 liter combustion engine with the same electric supplemental engine. This combo provides 100 horsepower for a very peppe drive.

The Toyota Prius hybrid system provides fuel economy in a different fashion. Its 6 horsepower electric motor provides power for normal driving conditions and generates no emissions. The vehicle is equipped with a 4 cylinder, 1.5 liter combustion engine witch delivers 76 horsepower when certain driving conditions require it.