In a technical paper delivered Nov. 14, 2001 at the SAE Truck & Bus Show in Chicago, Delphi said its Delphi's 42-Volt Energen-10 integrated starter-generator (ISG) has demonstrated significant fuel savings.

The paper details the fuel economy gain provided by a 42-Volt system for engine stop-start functionality, as implemented by Delphi in a sport utility vehicle. The study reports prototype vehicle results, consistent with vehicle simulation models that show fuel savings to be as much as 4 to 6 over the Federal Test Procedure-75 (FTP-75) driving schedule from stop-start functionality alone.

"The impact the 42-Volt ISG system has when activating all functions beyond that of the stop-start function is tremendous," said R. Scott Bailey, director of engineering, Delphi Energy & Chassis Systems. "Fuel economy improvements of 10 to 15 percent on the FTP-75 driving cycle are achievable and have been established both in simulation and in prototype vehicle testing."

Reduction in fuel consumption is achieved through the ISG's use of functions such as engine-off during cost-down and idle, early torque converter lockup with torque smoothing, deceleration fuel cutoff, regenerative braking and electrical launch assist, Delphi said. It also boosts the onboard power generation and energy storage, allowing for increased vehicle electrical loads.