Making Sense of the Newest Technologies
There are two types of hybrid electric vehicles, series and parallel. In a series hybrid, a small gas or diesel engine is employed as a generator, creating power to drive the electric motor and recharge the small battery pack. Thus, the gasoline engine never directly powers the vehicle. The batteries also store electricity generated through a process called regenerative braking, which is a brilliant method of recuperating up to half the motion energy (i.e. heat that warms the brake pads) vehicles traditionally waste during the decelerate-and-stop cycle. This type of braking allows the running gas motor to become a recharging generator, an especially useful feature for those of us who live in stop-and-go city traffic.
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| Parallel hybrids, such as the Honda Insight, produce the kind of power that match traditional gas powered engines. (Photo: Honda) |
By contrast, parallel hybrids, such as in the Honda Insight, have two discreet power sources, through a fuel tank that supplies fuel to the engine and also a set of batteries supplying power to an electric motor. Both the electric motor and the engine can drive the transmission, and in turn power the wheels. When they work together, they can provide the kind of power needed to keep up with and even surpass the flow of traffic.
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| Models such as the Honda Civic Hybrid have a continuously variable transmission which makes the best use of every drop of fuel. (Photo: Honda) |
One type of parallel hybrid has the car starting out in battery-powered mode, and then automatically firing up its internal-combustion engine when the batteries have lost 40 percent or more of their charge. The parallel hybrid's computer picks which form of power is on line, and makes barely noticeable switches between gas and electric mode, or merges them for quick acceleration. Another parallel type runs mostly on a small gas motor, switching on the electric for added boost. Many hybrids also have a continuously variable automatic transmission (CVT), which cuts down on energy lost during shifting.