What is a hybrid?

There are several different types of hybrid, but all of them work on similar principles.

Electric motors aid an Internal Combustion Engine (ICE), and usually provide a zero-emissions mode, where the vehicle only runs on electric power

The Toyota Prius shown here is the best selling hybrid vehicle in the world.

Engine & Motor

An Internal Combustion Engine is used to drive the wheels and charge the high voltage batteries.

The electric motor is often fitted between the engine and gearbox.

The engine may be slightly different to a conventional engine, as they often use an Atkinson-cycle for optimum efficiency.


As the engine runs, it produces power which is converted to electrical power through the inverter to charge the batteries. These in turn charge the 12V system which powers ancillaries such as the lighting systems.

Stop & Start

As the Internal Combustion Engine is stopped, and started, regularly in a Hybrid, there is often a Stop & Start system which replaces a starter motor with a belt-, or motor- driven device.

12V System

The Internal Combustion Engine requires a 12V system to run things like spark plugs, and this smaller 12V battery gets its charge from the main High Voltage Battery charge.

High Voltage Battery

As with Electric Vehicles, Hybrids have a high voltage battery pack for Zero Emission mode.

It is charged by the ICE, via the inverter. Because the battery is small, it can usually only power the vehicle solely by electricity for around 1 mile, often at a limited speed of 30mph.

Plug-in Hybrids (PHEV) have the ability to take a charge from a mains plug socket. These usually feature larger batteries than non-plug-in vehicles, giving extended EV-only range.