Hybrid Electric Vehicles

With the dwindling fossil fuel resources, the world might very soon run out of fossil fuels in the next 3 decades. It is imperative that these resources be conserved, hence scientists and engineers come up with solutions to save it. Hybrid vehicles can be one of the alternatives to save fuels. Hybrid electric vehicle uses two forms of energy to provide propulsion, one being the internal combustion energy and the other is a an electric motor powered by battery. Hybrid vehicles significantly reduce emissions and also increase fuel economy. It was Ferdinand Porsche to first introduce a gasoline-electric hybrid vehicle in 1901 by the name Lohner-Porsche Mixte Hybrid.

POWERTRAIN:

There are 3 types of powertrain in hybrid electric vehicles:

• Series hybrids: In a series hybrid, only the electric motor was used to propel the wheels of the car, whereas the Internal Combustion Engine (ICE) was used as a generator to power electric motors to recharge the battery. But these are not efficient for higher speeds, as the motor doesn't generate enough power.


• Parallel Hybrids: In a parallel configuration, both the electric motor and ICE can simultaneously power the drive train as they are connected to the mechanical coupling. A bigger ICE can be installed in this case to generate more power for high speed operation. The ICE also acts as a generator for recharging the battery.


• Power split Hybrids: It is a combination of both the series and parallel hybrids, thus making it more efficient. They are also expensive.

REGENERATIVE BRAKING:

Whenever we apply brakes, a lot of energy is removed from the car. This energy is the kinetic energy dissipated in the form of heat. Regenerative braking is a way of capturing this energy and converting it into useful electrical energy which can recharge the battery.

Plug-In Hybrids:

This is similar to the conventional hybrid vehicles, except that we use rechargeable batteries which can be recharged by an external power supply. It has a plug which can be connected to the electrical grid for recharging.

TOYOTA PRIUS:

It was the first mass produced hybrid car, launched in the year 1997 in Japan. It has a parallel hybrid power train. The biggest advantage of Prius is that it can run solely on electric power up to a speed of 24 kph. The engine does not come into play until the vehicle crosses 24 kph speed. This can significantly reduce the emissions in cities having huge traffic.

It has a unique power splitting device which can efficiently turn the engine for certain speed and load ranges. It is a planetary gear setup which can act as a parallel and as well as series hybrid. It can combine the powers of ICE and electric motor when required. The power split device allows series operation, where the ICE can either be used to power the car on its own for high speed operation or recharge the battery at low speeds.

Prius uses a 1.5 liter gasoline engine which can generate 76 hp and can run at a maximum speed of 5000 rpm. The electric motor can generate 67 hp for 1200 to 1540 rpm range.