IcanTomei Club : How Hybrids Work

A hybrid engine is a vehicle that uses two or more distinct power sources to move the vehicle. The term most commonly refers to hybrid electric vehicles (HEVs) which combination of an internal combustion engine and electric motors.

HOW HYBRIDS WORK

Hybrid-electric vehicles (HEVs) combine the benefits of gasoline engines and electric motors and can be configured to obtain different objectives, such as improved fuel economy, increased power, or additional auxiliary power for electronic devices and power tools.
Some of the advanced technologies typically used by hybrids include

• Regenerative Braking. The electric motor applies resistance to the drivetrain causing the wheels to slow down. In return, the energy from the wheels turns the motor, which functions as a generator, converting energy normally wasted during coasting and braking into electricity, which is stored in a battery until needed by the electric motor.

• Electric Motor Drive/Assist. The electric motor provides additional power to assist the engine in accelerating, passing, or hill climbing. This allows a smaller, more efficient engine to be used. In some vehicles, the motor alone provides power for low-speed driving conditions where internal combustion engines are least efficient.
• Automatic Start/Shutoff. Automatically shuts off the engine when the vehicle comes to a stop and restarts it when the accelerator is pressed. This prevents wasted energy from idling.

The schematic of hybrid engine:

Here, an example of the car that using the hybrid engine:

Honda Malaysia has launched the new Honda Insight which is the new B-segment Insight takes over the Civic Hybrid’s place as the cheapest hybrid car in Malaysia with a price tag of only RM98,000 OTR including insurance. This makes it exactly RM7,520 more than the most expensive Honda City.

For more understanding, you can see the animation on this link:
http://www.fueleconomy.gov/feg/hybridAnimation/swfs/hybridframe.html