How Car Makers Increase MPG
The days of car makers simply slapping together a car without much consideration for MPG are gone. With gas around $4 a gallon, those who commute seek cars that get at least 30 or more MPG. For instance, a person driving a 3.0 Suburu Outback wagon will average, at most, 22 MPG, around town, it is more like 18 MPG. By comparison, a 1967 Corvair six cylinder, gets the same MPG! If you commute 90 miles a day, round trip, the cost in gas is about $16 because about four gallons are used. A car with 30 MPG, in the same distance, costs $12 daily. Multiply either by an average of 20 work days a month and it suddenly becomes a REAL issue in gas costs for a month.
To increase MPG, car makers are using much more aluminum and plastic to decrease weight. That is why a car made in the 60-70s seem much more solid. Car design comes into play, with rounded front blended bumpers to reduce drag. The rear end design usually is an angular tail lamp and slanted glass to improve airflow over the car for less wind resistance. This includes panels under the car to reduce resistance. To decrease weight further, many new cars will no longer have a spare tire, only kits. The greatest MPG saver has been electric motors to assist with vehicle acceleration on highways. This alone can increase fuel savings to 5 MPG. The car designers try to make changes that allow the car to go further on a gallon of gas. Internally, new engines have coated pistons to reduce friction that will improve economy by 2%.
Driving all this is federal regulations that force car makers to improve MPG from 27 MPG today to 35 MPG by 2016 and 55 MPG by 2025.