It’s a prototype hybrid car that gets 150MPG, and goes 40 miles on electricity alone, drawing its power from a combination of lithium-ion batteries and ultracapacitors. The ultracapacitors provide a burst of energy to the engine, when needed. They are then recharged by the lithium-ion batteries. This avoids the problem of emptying the batteries too fast, which can cause them to heat up, and possibly catch on fire.
The prototype is based on a Saturn Vue Green Line, a hybrid crossover that General Motors builds using a low-cost belt-alternator system for its electric drive. It was created by AFS Trinity, and a running prototype will be shown at the North American International Auto Show in Detroit, which opens Sunday.
Typically, hybrids exploit the synergies of electricity and internal combustion by using only an electric motor at low speeds; the gas engine kicks in as speed increases, and both are used when maximum output is called for. AFS Trinity, on the other hand, took a purist position. In its system, the gasoline engine is not started until the batteries run down, an approach that Edward W. Furia, chairman and chief executive of the company, calls an “extreme hybrid.” Here’s a video of the car in action:
The rate of energy flow is also an issue as a hybrid car slows down, when its electric drive motor turns into a generator. This process, known as regenerative braking, converts the car’s motion into a powerful stream of electric current, but today’s hybrids capture only about half of the energy produced this way. Ultracapacitors can absorb a much higher percentage. The ultracapacitors take up about as much space as the lithium ion batteries, although they store a total of less than one kilowatt hour.
Because the AFS Trinity Vue runs long distances as a pure electric, it needs a full-size electric motor to go along with the full-size gasoline engine it uses in hybrid operation. While G.M.’s design for the Vue Green Line can get by with a small electric motor connected to the drivetrain by a belt, the AFS Trinity version has been modified with a 200-horsepower electric motor under the rear floor. The Vue Green Line’s standard hybrid system drives the front wheels, and the motor added by AFS Trinity drives the rear wheels.
So in its first 40 miles, the Vue is a rear-wheel-drive vehicle, and after that it is intermittently a four-wheel-drive vehicle, with the energy from regenerative braking captured by the capacitors and funneled through the motor driving the back wheels. “It saved us from mechanical integration and made it basically a software integration,” Mr. Bender said. But the ultracapacitors could be used in any kind of design, he said.
The idea behind the AFS Trinity is based on a widely accepted rule of thumb: the vast majority of drivers travel fewer than 40 miles a day. According to AFS Trinity, a driver who went 40 miles or less a day six days a week, and 100 miles once a week, would be traveling 150 miles for each gallon of gasoline burned, spending a little less than $8 for the gasoline and a little less than $8 for the electricity. The total fuel cost of $15.49 is about one-third of what it would cost for the gasoline to propel a conventional hybrid like the Lexus RX 400h the same distance, by AFS Trinity’s calculation.
Via: New York Times