|Valeo SA’s start-stop system uses a reversible stater alternator (above) to shut down an engiine and restart it when needed.|
Used most often at stop sign and lights, the start-stop technology reduces fuel consumption up to 10 percent, says Daniel Richard, research and development director for Valeo Electrical Systems.
The system uses a reversible belt-driven starter alternator located at the same position as a conventional alternator.
Valeo says the new system combines the functions of the starter and an alternator in one unit integrating the reversible electric machine and associate electronics. Quick engine startup is due to electronic control over the reverse motor mode. When it is in alternator mode it generates a high electrical output with increased efficiency.
Richard says the program is based on high-series production and has no investment cost for automakers who want to add it to their vehicle. The system will hit the market on an unidentified mid-size vehicle next year. It can be used in both gas and diesel applications.
Additionally, it is compatible with current electrical architectures.
Start-stop also is environmentally friendly. Besides the reduced fuel consumption it also provides a six percent reduction in carbon dioxide levels. Valeo also points out that it reduces vehicle noise levels at standstill which is 30 percent of urban environment driving time.
For its next generation, start-stop will use a motor-alternator reversible system. Due in 2006, this system also delivers additional torque to the engine. The torque output is comparable to a 2.0L diesel engine but the automaker can use a much smaller and lighter powertrain.
It also regenerates braking energy into electrical energy. When the driver lifts their foot off the throttle, the starter-alternator begins converting the vehicle’s kinetic energy to electrical energy. It is then stored in the battery, Valeo says.