Improving SUV fuel economy

Delphi is pursuing a strategy of engine shutdown and adding torque from an electric motor with its new 42-V integrated starter-generator.

Vehicle manufacturers are looking for ways to improve the fuel economy of light trucks, including sport utility vehicles (SUV), without affecting performance or utility. One possible solution in accomplishing this objective is the 42-V integrated starter-generator (ISG) under development at Delphi Corp. The ISG offers the ability to reduce fuel consumption by switching the engine off during coasting and idle, and employing early torque converter lockup with torque smoothing, regenerative braking, and electrical launch assist. It also boosts onboard power generation and energy storage, allowing for increased vehicle electrical loads.

ISG's primary attraction to vehicle manufacturers is adding capability to a conventional powertrain, resulting in greater fuel economy. In addition, ISG provides a secondary benefit of greater power generation than today's conventional alternators. The importance of these two attributes in one system cannot be understated. Therefore, to have a better knowledge of how to improve fuel economy, the impact of each ISG function must be quantified.