What are the different types of hybrid cars?

During the previous section, we learned that gasoline-electric hybrid vehicles marry a gasoline-powered internal combustion engine and an electric motor together to capture energy that's usually lost when a driver brakes. This energy is stored into a battery pack that provides the power for the vehicle to run. The batteries are constantly being charged while the car is in motion. The two types of hybrids that fit in the gasoline-electric categories are the series hybrid and the parallel hybrid.

In a series hybrid, the electric motor handles all the driving and the gasoline engine only recharges the battery pack. When the driver starts the engine, power is received from the battery pack to the electric motor which turns the wheels.  On longer trips (beyond 50 miles or so), the gas engine provides power. Series hybrids are more expensive than parallel hybrids because they carry larger batteries to provide power for higher speeds [source: HybridCenter]. The Fisker Karma is an example of a series plug-in hybrid.

Just like the series hybrid, the parallel hybrid uses both an internal combustion and electric engine. But this is where the similarities end. In the parallel hybrid, the conventional and electric engines are attached to one transmission which allows both of them to power the car at the same time. The fuel tank supplies gasoline to the engine while the generator charges the batteries. This type of hybrid is more suitable for traveling long distances. More drivers prefer parallel hybrids to series hybrids because they are more fuel-efficient. Examples of parallel hybrid vehicles are the Honda Insight, the Chevy Malibu and the Toyota Prius [source: Hybridcars.com].

There's also a variation called a mild hybrid, the least expensive of the hybrid bunch. The mild hybrid doesn't function on just the electric engine. Its electric motor assists the gas engine when more power is needed. When the car begins to slow down or sits still, the control unit shuts down the engine so the vehicle is not burning fuel or polluting the air like a conventional car. When the driver puts the car in gear or accelerates, the battery starts the motor again [source: Hybridcars.com]. In full hybrids, the electrical and gas engines can propel the motor by working together or operating on their own.

What's next for hybrids? Find out on the next page.

What's next for the future of alternative power vehicles? Well for starters, a car that runs on electricity comes to mind. When one hears the word, "electric," an episode of the futuristic cartoon "The Jetsons" might pop into the brain. But in this case, we're referring to plug-in hybrids and electric vehicles.

The plug-in hybrid, also known as the plug-in hybrid electric vehicle (PHEV), gets some or most of its juice from electrical energy stored in the car's batteries. The PHEV still uses a gasoline-powered engine, but the gas kicks in when the battery runs down. Some of the battery packs can be charged in standard electric outlets at home or work or in an electrical generator found in the vehicles. Other battery packs will require drivers to find larger power supplies typically not found at homes. Down the road, there are plans to build recharging networks and public recharging stations along regular highway routes [source: Hybridcars.com].

An electric car or electric vehicle (EV) gets its power from an electric motor instead of an internal combustion engine. The rechargeable batteries are charged the same way as the plug-in hybrids. In the past, critics raked them over the coals for their cost and because the short life of the car's battery limited drivers to short distances. Now, new technology and innovation have allowed modern car companies to improve upon the features of the electric car. Companies like Nissan are rolling out new versions of the EV. In fact, EV fans will have to wait until 2011 because dealers have already sold out the entire fleet of Nissan's all-electric Leaf [source: Business.Inquirer.Net].

The jury is still out on whether electric cars will be as widely received as hybrids were when first introduced more than 10 years ago. But whatever form they take, alternative vehicles will be around as long as people are looking for ways to limit the greenhouse effect and save a little cash at the same time.