Over the last several years, air pollution and our increased dependence on foreign oil have led to a number of initiatives to develop alternative forms of transportation. Although catalytic converters are now standard and the average car's fuel economy has improved somewhat, the situation is getting worse because of the increased number of cars. Electric vehicles are considered zero emission vehicles and some hybrid electric vehicles can currently operate as ultra low level emission vehicles.
California has developed an emission testing procedure that has been basically adopted by the United States Environmental Protection Agency (EPA). A number of other states are developing similar regulations and test. One critical component of the emissions testing program is the On-Board Diagnostics II (OBDII) system which is to be in place on all new vehicles by 1998. OBDII can provide information about failures of any of the vehicles systems that might increase emissions over the use of the car.
Although significant improvements have been made in electric vehicles, their driving range, time to recharge and battery lifetime will continue to limit their viability as general use vehicles. One possible alternative to the purely electric car is the hybrid electric vehicle (HEV). An HEV is a cross between an electric vehicle and a conventional internal combustion engine (ICE) vehicle. Frequently, to further reduce emissions, the ICE runs on an alternative fuel, such as, compressed natural gas, ethanol, methanol or propane. The ICE operates to provide energy to power the car and, in some cases, to recharge the batteries.
Industry and governmental organizations have developed a number of electric and hybrid electric prototype vehicles. All of the major automotive manufacturers have electric vehicles in development. In addition, a number manufacturers are developing hybrid electric prototype cars; including Ford, General Motors, Chrysler, Volkswagen, Volvo, and Lucas.2-7 "As further testimony to the promise of HEVs the California Air Resources Board is currently considering certifying them as zero-emission vehicles."2
Until recently the main consideration for HEVs was to provide reduced emissions while providing an extended driving range. However, the Partnership for a New Generation of Vehicles (PNGV), created in late 1993, has renewed interest in fuel economy. PNGV is a partnership between 11 U.S. government agencies and the United States Council for Automotive Research to "develop commercially-viable vehicle technology that, over the long-term, can preserve personal mobility, reduce the impact of cars and light trucks on the environment and reduce U.S. dependency on foreign oil."8 The United States Council for Automotive Research is a cooperative effort between Chrysler Corp., Ford Motor Co, and General Motors Corp. The three primary goals of the PNGV program are:
- significantly improve national competitiveness in automotive manufacturing
- apply innovations to conventional vehicles when they are commercially viable
- develop a vehicle that gets up to 80 mpg while maintaining the performance and cost of owning today's cars.
The PNGV goals also require consumer acceptance which means the vehicle must include HVAC, power steering, power brakes and other accessories that are consider standard on today's automobiles. The Departments of Commerce (DOC), Defense (DOD), Energy (DOE), Transportation (DOT), and NASA are the lead agencies.
The chief industrial participants in the PNGV program, Chrysler, Ford and General Motors, agree "that only a hybridized powertrain could keep fuel consumption down to the level required."3 "As research on HEVs continues worldwide, the hybrid is acknowledged to be the only current technology capable of reducing vehicle emissions and fuel consumption by a large amount in a short period of time."2
Since hybrid electric vehicles have two power sources, they can operate in a wide variety of configurations. The basic configurations are series, parallel and a combination of both series and parallel, sometimes called universal. Although the series configuration seems to be more popular, all configurations have proponents that feel that one system is clearly better than the others. "The choices open in both configuration and component sizes are endless. "3
Standard automobiles are becoming more and more complex with multiple microprocessor controls in all vehicles and on-board diagnostics systems. Alternative fueled and hybrid vehicles can substantially increase that complexity. An HEV can take many different forms. It may include a conventional internal combustion engine (ICE) vehicle running on an alternative fuel, such as, compressed natural gas, ethanol, methanol or propane. Gas turbines, Stirling engines and fuel cells have been proposed as alternatives to the ICE. The battery pack may be replaced or be supplemented by flywheel or ultracapacitor energy storage systems. The complexity of these new systems will require substantial research and development efforts.
Automobiles are becoming complex electro-mechanical systems. Neither mechanical nor electrical engineers are trained to understand the total system. There is a need for new, interdisciplinary, system engineers with multiple skills. To overcome this problem, an interdisciplinary program beginning at the master's level has been developed. This program not only provides for the course work necessary to develop the interdisciplinary approach, it also allows students with different degrees to progress through the program. The research projects the students will be working on are of great importance. These projects are truly interdisciplinary, team projects.