Hybrid Cars: the Technology Behind How They Work

There's been a lot of talk over the last few years concerning gas-electric vehicles, commonly called hybrids. For all the hype, there hasn't been much in the way of information concerning how they operate. They save gas, and are better for the environment, but how do they do this? I'll attempt to give a brief explanation below.

Hybrids commonly make use of two separate power plants: a traditional (though smaller and more efficient) internal combustion engine, and an electric motor/generator. Fuel consumption and emissions reduction are accomplished with a combination of three different mechanisms:

1. Reusing wasted energy through technologies such as regenerative braking.

2. Reducing the size and power of the internal combustion engine and using the better torque of electric motors to compensate.

3. Reducing wasted energy during idle and low output (cruising at speed) modes, generally by cutting power to the internal combustion engine (either partial or total).

Regenerative braking takes the kinetic energy lost during traditional braking and uses it to recharge the batteries and power other electrical systems on the vehicle. This results in free energy for the battery, and also reduces wear on the brake parts.

Reduction of traditional engine size and power results in better performance due to lessened weight of the engine plus optimized performance. The smaller engine operates continually in its ideal power range as opposed to traditional engines, which must operate in a much broader range, while having a narrow optimum range.

Energy is wasted by traditional engines at idle and during times of low power needs. Reducing or cutting power completely during these times reduces the amount of fuel consumption and emissions put out by the vehicle by quite a bit. When power is cut completely, as at idle, the vehicle switches over and runs on its electric motor. Simply pressing the accelerator pedal restores power.

Most hybrids also make use of other fuel saving techniques such as weight reduction. This is an engineering choice as opposed to a benefit of hybrid technologies. Several manufacturers announced that they would incorporate several aspects of hybrid technology during 2007. These would not be true hybrid vehicles, but would take advantage of several different aspects of the technology to save on gas and reduce emissions.

Trade offs include lessened power, and increased total vehicle weight due to the presence of the electric motor and battery pack. This weight will not affect the vehicle during urban driving, but will adversely affect fuel savings during highway driving. In short, hybrid vehicles are best suited to driving in an urban environment. Another perceived trade off is in initial cost. There have been rumors for a while now that the fuel savings versus initial cost never truly evens out. This is in fact not true. A recent study by Intelichoice shows that all hybrid models will begin to pay for themselves in a little less than five years.

Most vehicle manufacturers have hybrid models, including Ford, GM, Mazda, Nissan, Honda, Peugeot, Renault and Toyota. Currently the best selling hybrid is the Toyota Prius.