The Dodge Intrepid ESX2: From concept to creation

Hybrid car design has always been a challenge to the auto industry. It's expensive to create a car that get more miles to the gallon than today's vehicles, while at the same time producing fewer emissions and remaining appealing to consumers. Alternative fuel and energy sources are key components to the solution, but they pose problems of cost, weight, efficiency and size. The end product can be a highly fuel-efficient, environmentally friendly automobile, yet one with a very large price tag.

This special report examines the progress Chrysler is making in its hybrid concept car technology, with the Dodge Intrepid ESX2. The effort is designed to create a finished vehicle that is affordable to the customer.

THE MYBRID ENGINE

The tough part in designing concept cars is the powertrain, and ESX2 is no exception.  In a traditional hybrid car, two power sources alternate running the car: an internal combustion gasoline engine along with a battery and an electric motor. These batteries are unwieldy and heavy, cutting into the weight gains made in body improvements. They're also expensive, costing anywhere between $4,000 and $10,000.

ESX2 features a new diesel-electric approach that engineers like to call a "mybrid," or a mild hybrid. The mybrid relies mainly on the gas engine -- in this case, a 1.5-liter, 3 cylinder direct-injected diesel
with a much smaller battery for powering accessories such as lights and air conditioning. The battery, weighing only 133 pounds, also kicks in during hard acceleration.

Even with the smaller, lighter battery, running the accessories cuts into ESX2's efficiency, reducing it by 30 mpg. More work is needed to power the accessories while maintaining fuel economy.

Compared to a gasoline engine, the ESX2 diesel engine is 24 percent more efficient. It also emits far less carbon dioxide and particulate matter than a conventional gas engine. Still, the emissions need to be lower.

By continuing to rely on the engine, the mybrid ESX2 reduces, but doesn't eliminate, the high costs that come with electric cars. Even so, engineers believe it may be necessary to look to an alternative fuel source, such as dimethyl ether or dimethoxy methane, to achieve both fuel efficiency and clean air.

Along with its mybrid engine, ESX2 features a hybrid type of transmission. The five-speed transmission shifts like a manual, but operates like an automatic in the hands of the driver. Electric motors under the hood operate the clutch and gears in this prototype system, which is lighter and less expensive than the transmission in today's Dodge Intrepid. Most importantly, it adds 8 mpg to fuel efficiency.