Hybrid Electric Vehicle

 With the cost of fuel soaring to new highs and emission norms getting more and more stringent, consumers are looking for alternatives to reduce driving costs while govt. is looking for low tailpipe emission vehicles. One of the most interesting developments in search for low emission high fuel economy vehicles in the automotive world is the hybrid car. While these vehicles still use conventional fuel like gasoline, the fuel economy is considerably high and Emission extremely low. A hybrid vehicle is basically a vehicle that uses two or more distinct power sources to move the vehicle. Hybrid Electric Vehicle or Hybrid Electric Car combines an internal combustion engine and one or more electric motors. A hybrid electric vehicle (HEV) augments an electric vehicle (EV) with a second source of power referred to as the alternative power unit (APU). However, fuel efficiency depends upon the type of hybrid vehicles which are classified as Mild Hybrid, Full Hybrid and Plug-in hybrid Vehicles.

Gasoline Powered engines of mild hybrids can be switched off while the vehicle coasts, brakes and stops, and then restarted quickly. In India, in 2009, Honda launched its model Honda Civic Hybrid which is a mild Hybrid.

A Full hybrid can run on just Gasoline Powered engine or just the electric motor, or a combination of both. Recently Launched Toyota Prius is an example of full hybrid.

A Plug-In Hybrid vehicle run on rechargeable batteries upto few hundred kilometers before they switch over to gasoline powered engines. So, far in India no such vehicle is yet launched while in some countries still offer Plug-in Hybrid Vehicles.

Pure electric vehicles currently do not have adequate range when powered by batteries alone, and since recharging requires several hours, the vehicles are viewed as impractical for driving extended distances. If air conditioning or heating is used, the vehicle’s range is further reduced. Accordingly, the hybrid concept, where the alternative power unit is used as second source of energy, is gaining acceptance and is overcoming some of the problems of pure electric vehicles.

The hybrid electric vehicle operates the alternative power unit to supply the power required by the vehicle, to recharge the batteries, and to power accessories like the air conditioner and heater. Hybrid electric cars can exceed the limited upto 100-mile (160km) range-per-charge of most electric vehicles and have the potential to limit emissions to near zero. A hybrid can achieve the cruising range and performance advantages of conventional vehicles with the low-noise, low exhaust emissions, and energy independence benefits of electric vehicles. Hybrid vehicles can be categorized as (Annexure-1):

• Types by drive train structure –

•   Series Hybrid 
•   Parallel Hybrid 
• Series – Parallel Hybrid or Power Split

• Types by degree of hybridization –

• Micro Hybrid 
• Mild Hybrids 
• Full Hybrids

• Types by nature of the power source – 
• Electric-internal combustion engine hybrid
•  Electric-fuel cell hybrid 
• Internal combustion engine-hydraulic hybrid 
• Internal combustion engine-pneumatic hybrid 
• Human power and environmental power hybrids 
• Solar Photovoltaics (PV)