Mobility Solutions

Bosch Compact Alternative fuels From CNG powertrains to the Flexstart system for ethanol

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  • September 10, 2013
  • Mobility Solutions
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press release

Natural gas: cost-effective alternative for reducing CO2 emissions
Market: Over the past 10 years, the market has seen annual growth of 25 percent. Bosch compressed natural gas (CNG) technology can be found in series-produced passenger cars made by the Volkswagen Group, GM, Tata, Fiat, and Opel.

Technology: In cars fitted with Bosch CNG systems, driving behavior is the same regardless of whether the car is running on CNG or gasoline. The system can also start in CNG mode when it is cold, which means that customers can practically always drive on more cheaply priced natural gas. Other systems have to use expensive gasoline to warm up in the starting phase.

Costing: In Germany, CNG powertrains in passenger cars pay off as soon as annual mileage exceeds 7,000 kilometers. This is also because CNG is as much as 50 percent less expensive than gasoline. Compared with a conventional gasoline engine, generating the same power causes 25 percent less CO2 to be emitted. This is due to the chemical properties of this fuel source.

Diesel and natural gas: For commercial vehicles, Bosch offers a dual-fuel natural gas and diesel system. This system is compatible with CNG and LNG (liquefied natural gas), and allows up to 90 percent of diesel to be replaced by natural gas. Here, the diesel injection system acts like a kind of liquid spark plug. As it ignites the gas, there is no need for any additional ignition system.

Fleet customers: Compared with engines run purely on diesel, dual-fuel engines with a natural gas and diesel system emit 15 to 20 percent less CO2, as well as less particulate matter. At the same time, natural gas is cheaper than diesel fuel. This makes the diesel-natural gas variant especially attractive for customers with fleets of heavy trucks. Vehicles fitted with Bosch dual-fuel systems can also be run purely on diesel, and are thus suitable for areas with a limited natural-gas infrastructure.

Infrastructure: “Natural-gas systems already have the potential for reducing CO2 at low additional cost. Technologically, this is an area in which Bosch components lead the way. However, vehicles run on natural gas will only become more popular in the market if the infrastructure is significantly expanded.”
(Dr. Volkmar Denner, chairman of the board of management of Robert Bosch GmbH, responsible for research and development)

Flex fuel: driving on ethanol
Market: The lead market for ethanol-powered vehicles is Brazil. Approximately 87 percent of all vehicles newly registered there in 2012 run on alcohol. In 2013, the ten-millionth flex fuel vehicle was manufactured in Brazil. The reason for this is that the Brazilian government strongly promotes this alternative fuel. Other fuels, for example, must always contain a minimum of 25 percent ethanol. Other important markets for flex fuel vehicles are the U.S. and Sweden.

Cold start: The Bosch Flexstart system makes cold starts possible with pure ethanol (E100) even at temperatures below 15 degrees Celsius. Unlike conventional flex fuel systems, the Bosch system does not require any additional gasoline in order to pre-heat the ethanol. This task is assumed by glow plugs integrated in the fuel rail. They heat the ethanol prior to injection, making a cold start possible.

The challenge: Ethanol fuel poses considerable challenges for systems manufacturers, since the liquid can damage the installed components. For this reason, a special alloy is needed to protect parts such as pumps, rails, injectors, and even spark plugs. Calibration of the control unit is considerably more complex than with other combustion methods, requiring roughly 50 percent more effort.

Emissions reductions: Compared with conventional ethanol systems, Flexstart technology helps prevent up to 40 percent of the emissions associated with starting the engine. This is because this Bosch component uses glow plugs to pre-heat the ethanol fuel before it is injected. Pre-heating makes the ethanol-air mix more combustible, averting emissions where they are most likely to occur: in the cold-start phase.

Well-to-wheel: Ethanol powertrains offer the greatest potential for CO2 reduction from the well-to-wheel perspective – i.e. a calculation that considers the path taken by the fuel from production to combustion. In this context, Bosch regards the production of ethanol from organic waste as especially sustainable.

Click here to find further information.

At the 65th International Motor Show in Frankfurt, Bosch is showcasing technical solutions for connected mobility. A variety of innovations are helping to make road traffic cleaner and more efficient, as well as safer and more comfortable. Bosch is exhibiting its highlights at booth A04 in hall 8.

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,

PI8261 - September 10, 2013

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