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Choosing a Hybrid Car

8/10/2012
Fuel economy is one of the most important considerations for today's car buyers, so it is not surprising that more consumers are considering a hybrid model for their next new car.

Choosing a hybrid car is not much different than choosing a standard car. There are different makes and models available, different s and body types for sale, and four different kinds of hybrid systems to choose from. The main difference when buying a hybrid model is that the purchase is frequently determined by the kind of hybrid system the vehicle contains and the fuel economy it delivers, rather than how the car looks, who builds the car, or what body style it is.

In this article, we'll discuss the four main types of hybrid powertrains: mild hybrids, full hybrids, plug-in hybrids, and the lone electric car that features an onboard gasoline engine for a generator.

Mild Hybrids
A mild hybrid system employs a gasoline engine, electric assist motor, rechargeable battery pack, and regenerative braking to recharge the battery. Notably, a mild hybrid system cannot power the vehicle solely on battery electricity, not even at low speeds.

The idea with a mild hybrid system is that the electric motor assists the gasoline engine when the car is accelerating or is under load, such as when traveling up a hill. This allows the car to use a smaller, less powerful, and more fuel-efficient gasoline engine.

Examples of mild hybrid systems include eAssist from General Motors (as featured on the Buick Regal) and Integrated Motor Assist from Honda (as featured on the Honda Civic Hybrid).

Full Hybrids
Like the mild hybrid system, a full hybrid system employs a gas-fired engine, one or more electric assist motors, a regenerative braking system, and a rechargeable battery pack. The difference here is that with a full hybrid system, a car can operate at lower speeds running purely on the electricity stored in the battery.

Examples of full hybrid systems include Hyundai's Blue Drive system (as featured on the Hyundai Sonata Hybrid) and Toyota's Synergy Hybrid Drive system (as featured on the Toyota Prius).

Plug-in Hybrids
Take a full hybrid system, add more robust and sophisticated batteries capable of powering a car at higher speeds and for longer distances, and add a charging port that allows the car to be recharged using a standard power outlet at a home or office, and you've got a plug-in hybrid car.

The goal of a plug-in hybrid is to provide pure electric range for shorter commutes or errands, combined with a gasoline engine that kicks in to power the vehicle once the battery pack reaches a minimum state of charge. As this article is written, the Fisker Karma and the Toyota Prius Plug-in are the only plug-in hybrid models on sale. However, a number of new plug-in hybrids are expected to be offered for the 2013 model year.

Range-Extending Gasoline Generator
The Chevrolet Volt is unique in that it is a plug-in electric car that employs a gasoline engine to extend range. However, unlike a plug-in hybrid, the Volt's gas engine is used as a generator to supply energy for the battery once it reaches a minimum state of charge. The battery, then, continues to power the wheels. Only under extreme circumstances does the Volt's gasoline engine directly power the vehicle.