Siemens Soft Hybrid Stands Ready to Meet SUV Makers' Aggressive Fuel Economy Targets

    DETROIT, March 7 Siemens Automotive's Integrated Starter
Generator (ISG) technology, also known as a soft hybrid, is poised to play a
leading role in helping sport utility vehicle (SUV) makers reach their stated
fuel economy improvement goals of up to 25 percent by 2005.

    Demonstrating the technology's market readiness and refinement, Siemens
Automotive 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 (SAE)
2001 World Congress.

    "In real-world driving conditions, Siemens ISG-equipped test vehicles have
demonstrated significant fuel economy gains," said Kregg Wiggins, Siemens
Automotive vice president of Powertrain, North America.

    "Siemens' ISG represents a substantial step toward realizing our
customers' fuel economy gains with technology that soon will be introduced
into the market place," said Wiggins.

    The first of its kind to reach production, the Siemens ISG system will be
a supplemental power plant application on a European small car platform,
beginning in the next model year.

    The Siemens ISG replaces the conventional starter, generator and flywheel
of the engine and provides an auxiliary function as a convenient automatic
vehicle start-stop system for further improved fuel efficiency.  The system
switches off the combustion engine at zero load -- such as when standing at a
traffic light -- and automatically restarts it in less than one hundred
milliseconds when the gas pedal is pressed.  The pulse-start technology
accelerates the combustion engine to the required cranking speed (idle speed)
and only then initiates the combustion process for instant ignition, a feature
that helps reduce both fuel consumption and emissions.  ISG also optimizes the
use of electric energy, further reducing fuel consumption and emissions.

    The components of the ISG system are not subject to wear and tear and are
maintenance-free because of the system's brushless stator and rotor design.

    ISG's extremely compact dimensions allow it to be placed directly on the
crankshaft between the engine and the transmission.  High electric power
output, even at low speeds, enhances the performance of comfort and
convenience features.  These include the air conditioner, seat heater or rear-
window defroster.

    ISG is just as versatile when it comes to other disciplines.  In the boost
mode, for example, the starter briefly serves as a second engine to drive the
vehicle or provide acceleration in the low-speed range.  This provides a
short-term power boost of 15 kW, depending on the configuration of the ISG and
battery.  In the "retarder" mode, the ISG demonstrates yet another strength
with its ability to convert kinetic energy to storable electric energy.

    Driveability is improved significantly by the torsional-vibration damping
provided by the Siemens ISG.  Without active damping, load reversals and/or
abrupt acceleration could cause low-frequency vibration in the powertrain
that, in turn, might cause the vehicle to jerk.

    The introduction of the Siemens ISG also will bring about the transition
from a 14 to a 42-volt vehicle electrical system, a development that has been
generating enormous interest in the automotive industry, driven largely by the
increasing content of electronics solutions in vehicles.

    "With the advent of starter-generator and a supporting 42-volt vehicle
architecture, power struggles will soon become a thing of the past," said Ted
Vartabedian, Siemens Automotive system engineer for Electronic/Electrical
Distribution Systems.  "The increasing demand for electrical power during low
engine speed or cold starting will no longer overburden a vehicle's power
supply with ISG."

    An increasing number of energy consuming technologies, such as electrical
power assisted steering and electromechanical valve train, for example,
require generator outputs from four to eight kilowatts across the entire
engine speed range -- more power than conventional generators can provide.

    The Siemens ISG reaches a peak generator output of eight kW with an
efficiency of more than 80 percent across the entire speed range.  In
comparison, a conventional generator puts out 1.5 kW with a maximum efficiency
of 70 percent, which drops to a meager 30 percent at high speeds.