The Bosch Smart Electronic stop-start system, a technology that cuts the engine in traffic jams or at traffic lights, is now available on the latest BMW 1 Series petrol and diesel engine models. “This technology reduces fuel consumption significantly, especially in city centre driving,” said DR Volkmar Denner, member of the Bosch board of management. “This, and other systems supplied by Bosch, will help to reduce CO2 emissions further in the future.” The technology has gone into production at BMW from this month on the 1 Series. Bosch supplies the key components for this system, including a starter that has been developed specifically for this application.

With increasing fuel prices and an urgent demand for the reduction of CO2 emissions, there is an ongoing requirement for innovative solutions to tackle these issues. The  Bosch system provides a cost-effective way of conserving resources, as well as helping to protect the environment, by switching the engine off when the vehicle is stationary and automatically starting it again when the driver depresses the clutch pedal, prior to moving off.

The ECE 15 measuring cycle, the urban component of the New European Driving Cycle (NEDC), calls for twelve 15 second stops over a distance of seven kilometres. During such a journey, the Bosch system reduces fuel consumption and CO2 emissions by as much as eight per cent, depending on the vehicle. If the stops last longer, the actual savings on CO2 emissions and fuel can be significantly higher.

The Bosch stop-start technology required the development of a specially designed starter motor, the Smart Starter Motor. The company already produces the battery sensor required to detect the battery’s current state of charge and to communicate this information via the energy management system. “Bosch has drawn on its combined competence in drive trains, energy management and starter technology to develop this system and its control function,” said Denner.

Incorporating the Bosch stop-start technology requires no other change to the vehicle’s drive train or the engine. The system delivers an excellent cost-benefit ratio making it a very attractive system compared with alternative solutions. The number of engine starts the system has to make, in other words its service life, has been increased significantly for this application. In addition, the starter’s improved-performance electric motor, low noise and stronger pinion-engaging mechanism ensure that the engine starts reliably, quickly and quietly. Despite the increased number of functions, the starter is compact and can be integrated into the vehicle just as easily and conveniently as other starter motors.