More than 25 years ago, the government took action to increase the fuel economy of US vehicles due to the gasoline crisis of the early 1970s.The Energy Policy and Conservation Act of 1975 established fuel economy standards for automakers called the Corporate Average Fuel Economy (CAFE)standards. CAFE nearly doubled the fuel economy of passenger cars over a period of 10 years,and improved light truck fuel economy by about 60 percent.However, thanks it appears to the lobbying efforts of the petroleum industry, from 1985 through 2002 there were no improvements to fuel economy standards other than increases and decreases of a few tenths of a mile per gallon.
SUV sales have increased by a factor of 20 between the early 1980s and 2002, and now represent one out of every four new car sales in the United States. SUVs, pickups,and minivans are allowed to meet a much lower fuel economy standard than cars. Therefore, the average light truck's fuel economy is approximately 30 percent lower than the average car for 2002. In addition,the average model year (MY)2002 light truck produced 40 percent more emissions of greenhouse gases that cause global warming and roughly 1.5 to 5 times more nitrogen oxide emissions (a key smog forming pollutant) than cars.
The Scientists prove a point-
A group of scientists calling themselves The Union of Concerned Scientists (UCS) assumed the challenge to redesign the most popular SUV, the Ford Explorer, with the object of demonstrating the minimal effort needed to radically improve fuel mileage and safety. The UCS Guardian and UCS Guardian XSE were designed to have the same size and acceleration as the Ford Explorer which achieves 21 miles per gallon (mpg). The Guardians were also designed to have the same or improved hauling capacity.Both vehicles accelerate from 0 to 60 mph in about nine seconds and have even better hill-climbing ability than the Explorer. The Guardian achieves a fuel economy rating of 27.8 mpg by using a better engine,improved tires and aerodynamics,and a stronger but lighter unibody frame.Together,these technology improvements increase the price of the SUV by $600 over that of the Explorer. The Guardian XSE achieves better than 36 mpg by adding an even more efficient engine,along with an efficient six-speed automatic transmission and more extensive use of high-strength steel and aluminum to reduce its weight.These improvements cost $2,315. The Guardian XSE attained a higher level of fuel efficiency through the following modifications, listed with the corresponding decrease in fuel consumption: The addition of an ISG 10%, upgrade from 5 speed to 6 speed tranny 9%, upgrade from 2 to 4 valves per cylinder with variable valve control 13%, addition of precise metering direct fuel injection 20%.
Here the reader is introduced to a new member of the drivetrain component family, The Integrated Starter-Generator (ISG). The ISG is a power converter that will replace the starter and the generator in tomorrow's cars. Installed between the engine and the transmission, the ISG converts mechanical power into electrical power and vice versa. As an electric motor, it starts up the combustion engine almost noiselessly and much faster than any conventional starter. In its role as a generator, it produces electric power for the lights, air conditioning system, radio and all other energy-consuming components in the car and with greater efficiency than its conventional predecessors. Any excess power is used to charge the battery. And during braking, kinetic energy is converted into electrical energy and stored. At a stoplight, the combustion engine is automatically turned off as long as the driver keeps his foot on the brake pedal. When the brake is released, the starter-generator accelerates the crankshaft to idle speed within fractions of a second, and the engine control unit resumes fuel injection and ignition. The ISG provides a car with up to 15 kW more power and cuts fuel consumption by up to 15 %. The functions of the ISG, combustion engine, transmission and battery are coordinated by Integrated Powertrain Management software. To fully exploit all of the new system's advantages, the various components have to be able to communicate extremely quickly and efficiently. That calls for intelligent software development.
This year, an ISAD system for a light truck of General Motors will go into series production.
(http://www.ucsusa.org/documents/building_a_better_suv_web.pdf)