There still seems to be much confusion by most people on how a hybrid car functions. First of all unless you have a plugin hybrid, you do not charge the car from an external electrical source. The batteries are charged by the kinetic energy of the car when coasting or braking or by the gasoline engine. It is rather complicated how this all works but so far it has worked perfectly for me. Some of the time the engine is completely off such as when coasting or while the car is stopped.
|This Might be Typical at 70 mph Highway|
For the Toyota hybrid system the car can be powered entirely by the electric motor at lower speeds, powered entirely by the internal combustion engine, or a combination of electric and gas, this is controlled by the computer system in the car. Other hybrid systems may work slightly different. Your driving style and route can have much to do with the gas mileage results. The car begins moving first by electric to overcome the inertia, remember Newton's First Law of Motion?
|Under Some Conditions Mileage is Really High|
The internal engine in the Prius is an efficient design which helps greatly with the gas mileage. There are no belts on the engine for water pump, power steering, etc. The intake cycle of the engine is longer making for an engine than is more thermally efficient, that is more energy is converted from heat to useful mechanical energy. The claim is that this engine is 38% thermally efficient compared to around 20% average for typical gas engine. Without an electric assist for this type of engine the performance would be slow which is why it works well with the hybrid concept.
Other aspects of the car that contribute to efficiency are the transmission which constantly varies for the load. Tires that are designed for higher-mileage with pressure monitoring valve stems. The design of the body is more aerodynamic than most cars also.
I look forward to when full electrical cars are practical for most people.