Exhaust gas turbochargers for commercial vehicles from Bosch Mahle Turbo Systems

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Stuttgart, Germany, September 2010—Optimal operating maps and superior service life are the success factors for exhaust gas turbochargers from Bosch Mahle Turbo Systems for commercial vehicle engines.

In light of the Euro 6 and Tier 4 Final requirements, exhaust gas turbochargers that combine optimal operating maps with superior service life will be crucial for future commercial vehicle engine developments. Bosch Mahle Turbo Systems now offers this key technology for reducing fuel consumption and meeting emission standards over a wide range of variants.

After the company's founding Bosch Mahle Turbo Systems successfully acquired two projects in the passenger car segment involving both gasoline and diesel engines. The company is now poised to improve the quality of exhaust gas turbochargers in commercial vehicle engines using optimized simulation calculations, new materials, and new production processes.

The current product portfolio was originally created to serve passenger car gasoline engines from 45 kW to 220 kW and passenger car diesel engines from 35 kW to 165 kW. For the start of series production 2013, the company's portfolio has been expanded to include the assemblies BM79, BM90, BM110, and BM126. By using different rotor diameters (BM90 = 9.0 mm, for example) and combinations of turbine rotors and compressor wheels, engines can be endowed with power outputs of up to 530 kW.

Service life and responsiveness
Using select simulation tools, the responsiveness of an exhaust gas turbocharger can be determined before it even enters production. Because Bosch Mahle Turbo Systems develops its turbine rotors and compressor wheels in-house, it is able to respond quickly and efficiently to OEM demands. Optimized design programs used to design bearings make it possible to predict the rotordynamic response with an exceptionally high degree of accuracy already in the phase of design.

The product properties developed by Bosch Mahle Turbo Systems for passenger car applications are now being carried over to the commercial vehicle segment. These include the spontaneous buildup of boost pressure in typical acceleration phases, resulting from the rotor's low mass moment of inertia and from the low friction of its bearings. Additional design features such as twin shaft sealing rings on the turbine and compressor side enable the turbocharger to fulfill increasingly strict emission requirements.

To satisfy requirements for optimal responsiveness, Bosch Mahle Turbo Systems uses highly durable, precision-milled (not cast) compressor wheels, whose evenly balanced geometry effectively diminishes vibration and related noise of the compressor. Furthermore, a broad variant diversity can be realized with a small number of casting tools. This diversity allows the thermodynamic properties of exhaust gas turbochargers to be perfectly matched to OEM requirements.

Start of production for commercial vehicle exhaust gas turbochargers from 2013
The engineering site in Stuttgart, Germany and the manufacturing sites in Blaichach/Immenstadt, Germany and St. Michael, Austria are now prepared for the commercial vehicle applications as well. At the Stuttgart engineering site, hot-gas and engine test benches are available for testing. Starting in 2013, exhaust gas turbochargers will be produced on roughly 10,000 square meters of usable floor space in St. Michael.

Bosch Mahle Turbo Systems is a joint venture of Robert Bosch GmbH and MAHLE GmbH and thus participates in the strong understanding of the complete system for combustion engines and in the outstanding know-how in development and high-volume production of engine parts and components. The company was founded in 2008 and currently employs approximately 160 employees.