When a vehicle uses multiple propulsion systems to provide motive power, it’s called a hybrid vehicle. Combination of propulsion systems may be many types but most commonly used system is gasoline-electric which known as gasoline-electric hybrid vehicles. Electric hybrid vehicles use gasoline (petrol) to power internal-combustion engines (ICEs), and electric batteries to power electric motors. Modern hybrid cars are driven by electric motors powered by both batteries and an ICE. They recharge their batteries by capturing kinetic energy via regenerative braking. As well, when cruising or idling, some of the output of the combustion engine is fed to a generator which produces electricity to charge the batteries. Nearly all hybrids still require gasoline as their sole fuel source though diesel and other fuels such as ethanol or seen in occasional plant based oils. There are many types of hybrids, differentiated by how the electric and fueled halves of the power train connect, and at what times each portion is in operation. Two major categories are series hybrids and parallel hybrids. A series hybrid, the internal combustion engine is not directly connected to the drive train at all, but powers an electrical generator instead. This is similar to the operation of diesel-electric train locomotives, but they do not store auxiliary power in batteries for later use, and in fact is similar to an electric car which is recharged by electricity from a stationary fossil fuel power plant, except that the power plant is carried on board. Honda Insight Parallel systems connect both the electrical and internal combustion systems to the mechanical transmission. This is most common types of hybrid at present. They can be subcategorized depending upon how balanced the different portions are at providing motive power. Such as A full hybrid, sometimes also called a strong hybrid is a vehicle that can run on just the engine, just the batteries, or a combination of both (Prius and Escape). An Assist hybrids use the engine for primary power, with a torque-boosting electric motor also connected to a largely conventional powertrain. A Mild hybrid, which are essentially conventional vehicles with oversized starter motors, allowing the engine to be turned off whenever the car is coasting, braking, or stopped, yet restart quickly and cleanly. A plug-in hybrid electric vehicle (PHEV) is a full hybrid, able to run in electric-only mode, with larger batteries and the ability to recharge from the electric power grid. They are also called gas-optional, or griddable hybrids. A hydraulic hybrid vehicle uses hydraulic and mechanical components instead of electrical ones. Finally Pneumatic hybrid which use compressed air to power a hybrid car with a gasoline compressor to provide the power. Read Next: How hybrid cars work?