Siemens Automotive To Debut ISG-Equipped Vehicle at SAE World Congress

March 12, 2001 by Jeff Shepard

Siemens Automotive (Detroit, MI) announced that its integrated starter generator (ISG) technology, also known as a soft hybrid, may play a leading role in helping SUV makers reach their stated fuel economy improvement goals of up to 25 percent by 2005. The company took its ISG-equipped vehicle to the streets of Detroit for customer and media demonstrations, working its way to Detroit's Cobo Center, where it is on display this week at the Society of Automotive Engineers 2001 World Congress.

The Siemens ISG replaces the conventional starter, generator and flywheel of the engine and provides an auxiliary function as an automatic vehicle start-stop system. Siemens Automovitve claims that the system switches off the combustion engine at zero load and automatically restarts it in less than 100 milliseconds when the gas pedal is pressed. The pulse-start technology accelerates the combustion engine to the required cranking speed and then initiates the combustion process for instant ignition.

Siemens Automotive reports that the ISG's compact dimensions allow it to be placed directly on the crankshaft between the engine and the transmission. From this position, it serves as a second engine to drive the vehicle or provide acceleration in the low-speed range when in boost mode. In the retarder mode, the ISG converts kinetic energy to storable electric energy. In addition, the device provides torsional-vibration damping. Other features of the Siemens ISG include a peak generator output of 8kW, with an efficiency of more than 80 percent.

“In real-world driving conditions, Siemens ISG-equipped test vehicles have demonstrated significant fuel economy gains," stated Kregg Wiggins, vice president of the powertrain division of Siemens Automotive. Ted Vartabedian, system engineer for Siemens Automotive's electronic/electrical distribution systems, added, “With the advent of starter-generator and a supporting 42V vehicle architecture, power struggles will soon become a thing of the past. The increasing demand for electrical power during low engine speed or cold starting will no longer overburden a vehicle's power supply with ISG."

The Siemens ISG system will be a supplemental power plant application on a European small car platform, beginning in the next model year.