Auto Start-Stop Systems

What is auto Start-Stop technology in a car?

The start-stop technology automatically turns off the engine when the car stops and restarts it when the car is ready to move again.

In the city, vehicles are stationary for nearly 35% of the time (traffic jams, red lights…), with their engine’s idling needlessly. The Stop-Start system automatically switches off the engine when the vehicle is at a standstill and restarts the engine immediately, as soon as the driver lifts his foot off the brake or disengages the clutch, leading to a significant reduction in CO₂ emissions.

How does the Start-Stop technology work?

Two Valeo systems, the Valeo i-StARS starter-alternator and the Valeo ReStart reinforced starter, make this automation possible. These systems are compatible with gasoline and diesel engines, and both manual and automatic gearboxes.

The Stop-Start system provides fuel savings of up to 6% in European standard mixed cycle use, and savings of up to 15% in congested city driving.

Valeo i-StARS starter-alternator: an immediate start in silence

The Valeo i-StARS starter-alternator is installed in place of an alternator. The combustion engine is started immediately and silently thanks to the belt that permanently links the system to the crankshaft. The alternator mode features a new technology that improves the electrical efficiency of the system. In addition, the integrated control electronics makes it easier to package the system on the combustion engine.

The Valeo i-StARS starter-alternator optimizes the Stop-Start strategy required by the automaker. It enables the engine to be switched off and restarted before the vehicle has reached a complete standstill. Restarting is almost instantaneous (400 msec), silent and without vibration. The system is compatible with all manual and automatic transmissions.

Valeo ReStart: the reinforced starter

The reinforced starter, Valeo ReStart, is installed in place of a conventional starter and offers better durability to repeated stopping and starting. Valeo ReStart can be adapted to all types of engines, and all engine displacements, and can also start the engine at extremely low temperatures. Its integration is not intrusive, as the system does not alter the vehicle architecture. Valeo teams are currently working on the development of a new-generation of reinforced starter that can restart the combustion engine while it is still turning. This will increase the duration and number of stop phases, contributing to increased fuel efficiency.