Start/Stop Systems Cut Fuel Use, CO2 Emissions

FRANKFURT, GERMANY (Aug. 25, 2007) - Increasing fuel prices, ever-stricter emission limits, and the objective to further reduce carbon dioxide (CO2) emissions call for innovative solutions. One cost-effective way of conserving resources and protecting the environment is the start/stop system. Start/stop systems switch off the internal combustion engine when the vehicle is at a standstill - for example, in traffic jams or at red lights. This helps effectively reduce fuel consumption and CO2 emissions, particularly in urban traffic.

For companies such as Bosch, the opportunities for inclusion in new vehicles have been increasing. "Bosch has developed the start/stop system to the stage where it is ready for series production, and is now working intensively with several automobile manufacturers to set up the production process," explains Dr. Steffen Berns, executive vice president-engineering of the Bosch Gasoline Systems division. "Bosch has drawn on its combined competence in drivetrains, energy management and starter technology to produce this starter system and to manage its operation." Berns adds that the system has led to reductions in both fuel consumption (of up to 4 percent) and CO2 emissions (by up to 8 percent). 

Bosch developers also designed a special starter for the start/stop system that the company has been supplying to BMW since March 2007. The robustness of the starter has been significantly increased for this application. In addition to the improved-performance electric motor, the system also features a low-noise, stronger pinion-engaging mechanism to ensure that the engine starts reliably, quickly and quietly. 

Despite the increased functionality, the starter is compact, and can easily be integrated into vehicles. The company also supplies a battery sensor that, when integrated into engine control units, can detect a battery's current state of charge and communicate this information to the energy management system. 

Following its use in the BMW 1 series, the start/stop system is also fitted as standard equipment in the majority of the BMW Group's Mini models as of August, and to the new Mini Clubman beginning in November.

(Source: Robert Bosch GmbH)