MITSUBISHI FUSO ECO-HYBRID CONCEPT
By Steve Sturgess, Executive Editor
Claiming significant improvements in fuel economy and lower emissions, Mitsubishi Fuso has developed a demonstration commercial hybrid electric vehicle (HEV).
The Fuso hybrid commercial truck combines a small, clean-burning diesel engine, an ultra-slim electric motor/generator and advanced lithium-ion batteries in a drive train that also includes a high-efficiency automated mechanical transmission.
The result is a medium-duty truck – equivalent to our Class 4 – that achieves up to 30 percent better fuel economy in delivery applications and also produces significantly less emissions than its standard diesel-only model.
The demonstration Fuso is a Japanese-spec distribution truck called the Canter.The truck features a narrow "standard" cab, but is basically the same as the Fuso FE 145, introduced to the North American market two years ago.The Japanese Eco Hybrid features a parallel hybrid drive system, which incorporates the company's newest technology.
While the hybrid layout is a new development for Fuso, the individual components in it are all proven designs.The small 123-horsepower turbocharged diesel engine (smaller than the 147-horsepower diesel in the North American FE) is the same one used in conventional medium-duty truck service in Japan for several years.This proven diesel is coupled to an ultra-slim, 47-horsepower, brushless permanent-magnet synchronous electric motor/generator. Power from both the diesel and electric drives is carried through a Mitsubishi Fuso Inomat II automated mechanical transmission, similar to the ones that have been used in Fuso Class 8 trucks for a decade.
The hybrid system switches its operational mode according to the driving situation.The electric motor is used to drive the vehicle when starting off. During hard acceleration, both the diesel engine and electric motor/generator power the vehicle. When cruising, the vehicle is driven by the diesel engine only, like a conventional vehicle.When slowing down or braking, the electric motor/generator functions as a generator to brake the vehicle.The generator converts brake energy into electric energy and stores it in the lithium-ion battery.
Contrast that to a conventional truck. Stopping it requires a braking system that will convert the truck's kinetic energy (its forward motion) into heat energy that is ultimately dissipated into the air via the brake pads and disks. All of that heat energy is wasted.The next time the truck accelerates, it has to burn more fuel to do it.
In the Fuso Eco-Hybrid, every time the driver lifts a foot off the accelerator, the diesel engine is taken offline (that is, the clutch is disengaged), and an inverter automatically switches the electric motor/generator into generator mode, feeding electrical power back to the batteries. Instead of the kinetic energy of the truck being converted into waste heat, it's converted into electrical energy that's stored onboard, then re-used by the electric drive motor.
This regenerative braking is at the heart of the HEV's efficiency.
"The Mitsubishi Fuso Canter Eco Hybrid demonstrates the potential for combining environmental performance and efficiency in an alternative- drive vehicle," said Bob McDowell, president and CEO of Mitsubishi Fuso Truck of America.
The Fuso Canter was displayed at two of the major spring trucking shows in the United States and is wrapping up an exhibition tour.The purpose of exhibiting the prototype was to help the company gauge interest among potential U.S. customers.The Canter will soon head off to Stuttgart, Germany, for a DaimlerChrysler event (DaimlerChrysler has a 85 percent holding in Fuso).Then it's on to Britain for a major truck show there.
Mitsubishi Fuso's Canter Eco Hybrid goes into limited production in Japan later this year.The additional cost for the hybrid option is significant, but the truck appeals to the Japanese corporate, municipal and public service sectors' philosophy of "work with conscience." Helping that noble effort is a Japanese government incentive of around $10,000 per vehicle. According to Fuso, this subsidy covers about two-thirds of the upcharge for the hybrid drive.
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