Bosch has developed a start-stop system that switches off the combustion engine when the vehicle is stationary – in traffic jams or at red lights, for example. "Especially in city driving, this technology significantly reduces fuel consumption," said Dr. Volkmar Denner, member of the Bosch board of management, when explaining the benefits of the system. "This and other systems supplied by Bosch will help to reduce CO
2 emissions further in the future." The technology will soon go into production at BMW: first variants of the 1-series BMW will feature it as standard equipment from March 2007. Bosch supplies the key component for this system: a starter that has been developed specifically for this application.
Increasing fuel prices, ever stricter emission limits, and the objective to reduce CO2 emissions further call for innovative solutions. One cost-effective way of conserving resources and protecting the environment is the Bosch Smart Electronic start-stop system. It switches the engine off when the vehicle is stationary, and starts it again automatically as soon as the driver wishes to move off again – an intention which can be indicated by depressing the clutch pedal, for example. The ECE15 measuring cycle, the urban component of the New European Driving Cycle (NEDC), calls for twelve 15 second stops over a distance of seven kilometers. During such a journey, the Bosch system reduces fuel consumption and CO2 emissions by as much as eight percent, depending on the vehicle. If the stops last longer, the actual saving of CO2 emissions and fuel can be significantly higher.
For the Bosch start-stop approach, developers have designed a specially adapted starter, the Smart Starter Motor. There is no need for any further adjustments to the drive train or the engine. This gives the system its excellent cost-benefit ratio, and makes it so attractive compared with alternative systems. The number of engine starts the starter has to make – its service life, in other words – has been significantly increased for this application. In addition, the starter's improved-performance electric motor, and a low-noise, 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 quickly as other starters. "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. The company already produces the battery sensor that is needed to detect the battery's current state of charge and to communicate this information via the energy management system.
