- + Bi-turbo technology drives BMW’s first hybrid
- + New materials and advanced aerodynamics set the benchmark
The Ultimate Driving Machine Turns Green
Posted 08.12.2009
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The excitement is building up. BMW’s X6 and 7 Series 4.4L V8 hybrids – boosted by a Honeywell bi-turbo system – are expected to arrive late this year and in early 2010 respectively. The hybrid models in particular are seen by the world-renowned German auto manufacturer as important in meeting growing demand for fuel-efficient performance cars in the US.
What’s new about the hybrid technology BMW developed to accompany the new V8 engine is that unlike engine stop-start hybrid functionality, BMW opted to incorporate an electric motor into the 4 wheel drive transmission so that the electric drive can function without the engine being started – ideal for low speed maneuvering and great for even better fuel economy.
As soon as the driver demands torque or strong acceleration, the internal combustion engine is fired-up and the turbos kick-in – delivering 325kW power output, 650Nm of torque…and impressive fuel economy.
From Honeywell’s perspective, the hybrid required a specific turbo qualification procedure to take into consideration the variation in engine duty cycle brought about by the start process. This added complexity in terms of oil pressure, temperature, speed ramp-up and control through the engine management system.
“We had an engineer embedded with the BMW powertrain team from the outset of the engine program,” said Frederic Nicolle, Honeywell’s BMW Application Engineering Manager. “This meant that we were able to contribute to the key discussions and to add value at every stage in terms of turbo performance, integration and control.”
The architecture chosen by BMW meant putting the two turbos between the cylinder banks, which reduced the available space to an absolute minimum and created considerable challenges for Honeywell engineers from a packaging and thermal control perspective.
The development of the bi-turbo system was truly a team work, drawing support from Honeywell engineers in France, the UK and the US. The intensive collaboration focused on refining the aerodynamics to optimize the design of the compressor and turbine housings and the application of advanced simulation tools to predict and validate thermo-mechanical behavior of different materials, from which the most suitable materials were selected for optimum performance.
“This program has set the benchmark in terms of validation and qualification for advanced gasoline turbo systems,” said Frederic Nicolle, “and it places Honeywell firmly at the forefront of gasoline engine boosting technology.”
Photo Credit: BMW, Honeywell
Hot Wired For Progress
A multi-million dollar investment in thermo-mechanical simulation is turning the heat up on technological advances in turbo programs at Honeywell.
As temperatures continue to rise, particularly in gasoline powertrains, engineers are using the latest simulation techniques to run sophisticated thermal fatigue calculations to prove the parameters of specific turbocharger designs – and to quicken product development cycles.
Thermo-mechanical analysis uses computer data and modelling to assess the effect of heating and cooling on materials and on turbo system components such as turbine housings and wheels.
Honeywell has developed its own unique suite of simulation software tools to replicate the exact operating environment of the turbo, taking account of engine duty cycles, temperature, materials resistance, packaging and detailed design elements to predict performance and reliability. This ensures that design qualification is quicker, is founded on an ever deepening understanding of materials technology and capability and that system performance and projected reliability are in step with program requirements before production begins.
This knowledge is of vital importance as operating temperatures climb – indeed Honeywell is now using this world-leading capability to investigate the development of its own special materials for the turbo applications of the future.
© 2009 Honeywell International Inc.