Mobility Solutions

Even lower consumption and CO2 emissions Advanced Bosch start/stop system saves even more fuel

  • Advanced start/stop system stops the engine even when rolling to a halt
  • Start/stop coasting saves as much as ten percent more fuel
  • Synchronized restart for improved system reaction time
Add to my press materials
Save text
  • September 13, 2011
  • Mobility Solutions
  • Press releases

press release

When it is stopped, an engine does not need any fuel. This is the principle behind start/stop systems, which simply stop the engine at traffic lights or in traffic jams. In order to further reduce consumption, and thus CO2 emissions, Bosch engineers are gradually extending engine shutdown-times. This will apply initially to the time when the vehicle is rolling to a halt, then even to periods when drivers stop pushing the gas pedal. “Depending on the type of driver, the improved start/stop systems can save an additional ten percent of fuel,” says Dr. Ulrich Kirschner, president of the Bosch Starter Motors and Generators division. Since the first start/stop system went into series production in 2007, Bosch has sold more than four million start/stop starters.

In the first-generation start/stop system, the engine is not stopped until the vehicle has come to a halt. The advanced start/stop system extends the scope of engine shutdown. For example, if a driver brakes for an approaching red light, the engine is stopped while the vehicle rolls to a halt. If the driver wants to move on and depresses the gas pedal, the motor restarts without delay. A synchronized restart function helps here, allowing the starter pinion to smoothly engage with the decelerating engine. The speed of the starter is synchronized to that of the crankshaft, and then meshes with the ring gear. Apart from a special starter design, which separates the pinion engagement phase from the starting phase, and a modified engine management software, no extra components are necessary. While start/stop systems have so far saved up to five percent in the New European Driving Cycle (NEDC), up to seven percent is possible with the new system.

Zero consumption, even when on the move
The synchronized restart function also helps to reduce system reaction time during start/stop coasting. The vehicle's momentum is used to propel it forward with its engine disengaged and stopped, consuming zero fuel and causing zero emissions. The engine is restarted as soon as the driver depresses the gas pedal. The system works at the speeds typical for vehicles in urban, overland, and freeway driving. In real operating conditions, this leads to extra fuel savings of as much as ten percent. Even when coasting for extended periods, a redundant design of the power network ensures that safety-related functions such as power steering or braking still work.

The advanced Bosch start/stop systems are available for vehicles with manual and automatic transmission. Although it is subject to greater stress, the starter is designed to last the service life of the vehicle. For Dr. Ulrich Kirschner, the advantages are clear: “With our optimized start/stop systems, we can help to further reduce CO2. Their simple technical design, and the favorable price this entails, as well as their intuitive function stand them in good stead for wide-scale use in all vehicle classes and markets.”

Click here to find further information.

Mobility Solutions is the largest Bosch Group business sector. In 2015, its sales came to 41.7 billion euros, or 59 percent of total group sales. This makes the Bosch Group one of the leading automotive suppliers. The Mobility Solutions business sector combines the group’s expertise in three mobility domains – automation, electrification, and connectivity – and offers its customers integrated mobility solutions. Its main areas of activity are injection technology and powertrain peripherals for internal-combustion engines, diverse solutions for powertrain electrification, vehicle safety systems, driver-assistance and automated functions, technology for user-friendly infotainment as well as vehicle-to-vehicle and vehicle-to-infrastructure communication, repair-shop concepts, and technology and services for the automotive aftermarket. Bosch is synonymous with important automotive innovations, such as electronic engine management, the ESP anti-skid system, and common-rail diesel technology.

The Bosch Group is a leading global supplier of technology and services. It employs roughly 375,000 associates worldwide (as of December 31, 2015). The company generated sales of 70.6 billion euros in 2015. Its operations are divided into four business sectors: Mobility Solutions, Industrial Technology, Consumer Goods, and Energy and Building Technology. The Bosch Group comprises Robert Bosch GmbH and its roughly 440 subsidiaries and regional companies in some 60 countries. Including sales and service partners, Bosch’s global manufacturing and sales network covers some 150 countries. The basis for the company’s future growth is its innovative strength. Bosch employs 55,800 associates in research and development at 118 locations across the globe. The Bosch Group’s strategic objective is to deliver innovations for a connected life. Bosch improves quality of life worldwide with products and services that are innovative and spark enthusiasm. In short, Bosch creates technology that is “Invented for life.”

Further information is available online at and,

PI7481 - September 13, 2011

Your contact person for journalists

Stephan Kraus

+49 711 811-6286 Send Email

Share this information