|
|
|
|
FUEL FOR THE FUTURE
June 3, 2002 -The transportation industry is the only industry that has only one primary source of fuel: gasoline. Developing another source is the next essential step in the evolution of motor vehicles. Achieving this goal would reduce critical resource consumption, dependence on foreign oil, and air pollution. The ultimate goal of the vehicle makers is to produce affordable, reliable, zero-emissions vehicles.
Hybrid Electrics
The alternative fuel powered vehicle of today is the hybrid electric vehicle (HEV). An HEV combines an internal combustion engine with the battery and an electric motor. Besides benefiting the environment by creating lower emissions, HEVs also increase fuel economy. This is achieved through regenerative braking. The energy that is recovered during braking is stored by the battery and is later used.
The lack of battery technology is one of the downfalls of the HEV, as well as the all-electric vehicle (EV). The types of batteries that are being tested and used are high-powered lead acid, nickel-metal hydride, lithium ion, and lithium polymer. Each of these types has advantages and disadvantages including the amount of power, cost, safety, reliability, specific energy, cold temperature performance, high temperature performance, calendar life, cycle life, heat generation, self-discharge, and abuse tolerance.
 |
Figure 1-This Integrated Motor Assist system is a second generation HEV engine for Honda.
|
|
In late 1999, the first hybrid vehicle that was available for purchase in the United States was the Honda Insight. In 2003, the Honda Civic will be an addition to the hybrid family. The Honda HEV engine is called the Integrated Motor Assist (see Figure 1). Since Toyota’s introduction of the Prius to Japan in late 1997, Toyota has sold over 100,000 hybrid vehicles to the world as of the end of March 2002. Ford plans to release an Escape Hybrid in 2003. The Escape Hybrid uses a 300-volt nickel-metal-hydride battery. Figure 2 is a look under the hood of an Escape Hybrid. DaimlerChrysler
 |
Figure 2-The underhood of an Escape HEV.
|
|
has developed a "through-the-road" (TTR) hybrid powertrain system, so called because there is no physical connection between the front and rear axles or the engine and the motor. These computer-controlled hybrid vehicles are said to have a 20-30% improvement in fuel efficiency and lower emissions, compared to conventional vehicles. The TTR powertrain is being incorporated into a wide range of platforms, including a Dodge Durango, Jeep Liberty, Chrysler Sebring, and a Dodge Ram "Contractor Special." The Dodge Ram Contractor Special, at least, will be available to the public in the 2004 model year.
The Fuel Cell Answer
Despite the fuel savings with hybrid electric vehicles, this technology is still dependent on gasoline. And that dependence is expected to continue at least through the next decade. So where are the vehicle makers focusing their attention for the future, since the EV is in a quagmire with battery technology? At this time, the hydrogen fuel cell appears to be the answer.
A fuel cell uses an electrochemical reaction to create electricity using hydrogen and ambient air, resulting in water vapor as the only emission. The obstacles that must be overcome before a vehicle using this type of power can be mass produced include onboard storage and fuel infrastructure.
 |
Figure 3-The entire powertrain on this fuel cell prototype is in a 150 mm (6") platform GM calls a "skateboard." (Courtesy of GM)
|
|
Once these hurdles are crossed, a vehicle such as shown in Figure 3 is one of the many possibilities. This is a General Motors concept vehicle called the Autonomy, which is projected to be on the road within the next 10 years. This vehicle gets its power from a hydrogen fuel cell and 42-volt electrical system. The frame, front and rear crush zones, and fuel cell are contained in a six-inch-thick skateboard-like chassis that has a 20-year life expectancy. There is no engine, foot pedals, nor steering wheel. The vehicle is driven using an adjustable steering guide called X-Drive. The driver is allowed to sit wherever they want because there is no standard driver’s seat location. Electrical systems have replaced the mechanical ones, therefore eliminating engine oil, transmission fluid, and brake fluid. The steering, braking, ride control, and handing are controlled using drive-by-wire technology. As for the body of the vehicle, multiple interchangeable bodies are being designed to fit the mood and personality of the driver.
 |
Figure 4-Under the hood on a Ford Focus fuel cell vehicle.
|
|
Other concepts are less dramatic. Ford Motor Company has a direct-hydrogen-powered fuel cell vehicle called the Focus FCV (see Figure 4). This is Ford’s first working production-prototype. A fleet of these vehicles is intended to be ready for customer test drives by 2004. In Europe, the Mercedes-Benz Citaro bus is entering the trial drive and production setting phase after being initially launched in 1997. Thirty of these fuel cell powered busses will be distributed all over the country. The busses are powered by a renewable energy source and are emission-free. The bus is 12 m (39 ft) long, able to hold about 60 passengers, and has a range of about 200 km (124 miles).
Conclusion
This has been a short glance into what vehicle makers perceive as the future of the industry. It’s a future that is not only practical, but necessary, if dependence on one type of fuel source and increasing harmful emissions are to ever end.
|
|
