Once pooh-poohed by the Detroit Three as a bogus way to improve fuel economy, the five millionth start-stop starter was built today in Hildesheim, Germany by Robert Bosch. Stop-start systems, now in production by virtually all automakers and their various suppliers, provide ~5% improvement in fuel economy depending on which testing cycle is cited, are particularly effective in commutes with gridlocked traffic. Start-stop is simply a method shutting an idling engine down and restarting it when the driver steps on the accelerator.
Volkswagen explored this concept with demonstration units decades ago. However, the effectiveness of electronic controls monitoring such variables as battery state of charge and engine temperature and heater operation, makes stop-start systems viable with no negative aspects. Stop-start is virtually undetectable to drivers, except for a slight shudder on engine reactivation. Once you drive a vehicle with start-stop you will go crazy when idling and realizing that you are getting zero miles per gallon for no reason other than to make oil companies wealthier.
“We are expecting every second new car in Europe to be fitted with a start/stop system by 2013,” says Dr. Ulrich Kirschner of Bosch.
The data seem clear: In the New European Driving Cycle (NEDC), start/stop systems reduce fuel consumption, and CO2 emissions, by up to 5%. In the NEDC urban cycle, there’s an 8% fuel economy gain. In heavy urban traffic during peak hours, potential fuel economy gains are even greater.