Downsizing to meet OEM challenges:
MAHLE Powertrain (MPT) is part of the worldwide MAHLE Group which employs over 40,000 people in 110 production and R&D offices around the world. MPT provides Integrated Powertrain Solutions (IPS) from concept to manufacture.
MPT is constantly exploring new ways to improve the efficiency and performance of engines to meet the demanding objectives Automotive OEM’s are faced with today, i.e. to reduce fuel consumption and emissions. MPT’s key expertise lies in the development of high performance engines with low emissions and excellent fuel economy through the optimisation of gas exchange, combustion, friction and durability.
This strategy is being demonstrated by the development of MAHLE’s own state of the art three-cylinder 1.2-litre downsizing technology demonstrator engine which has been designed, built and tested at Northampton in the UK.
One of the objectives of the project was to design a compact engine with high specific power output by using a turbo charger combined with state of the art direct injection technology and variable valve timing. This ensures that vehicle performance targets can be met using the smallest capacity engine thus minimising throttling losses which otherwise leads to high fuel consumption.
Other auxiliary drive losses in the engine must be kept to a minimum if the benefit of the engines inherent low fuel consumption is to be maximised. Reducing the power requirement of both the lubrication and cooling systems is key to achieving these low auxiliary drive losses.
This revolutionary engine development uses Flowmaster to model and simulate systems to optimise selection and sizing of components and technology from MAHLE.
Designing the Lubrication & Cooling Systems
Flowmaster is used throughout the design process. From the initial concept stage, Flowmaster allows engineers to understand what is or isn’t feasible and identify any problems long before the engine reaches the test bed.
Flowmaster is used to build a full model of the lubrication and cooling systems to meet the exact requirements of the engine. By understanding these requirements, along with the parameters and tolerances of the available components MAHLE have been able to optimise the design of the engine, thus reducing power losses and ensuring high reliability. A downsized engine puts high demands on the lubrication system, therefore the accuracy and quality of information is paramount.
For the lubrication system design, engineers at MPT use Flowmaster to optimise the pump capacity and drive ratio. At low engine speeds the oil pump pressure relief valve (PRV) remains closed, forcing all of the flow from the pump to the consumers. Under these conditions it is critical that the pump capacity matches the engine’s requirements and acceptable oil pressure targets are achieved. By optimising the combination of capacity and drive ratio MPT engineers can minimise the pump power consumption under normal driving conditions. The efficiency of an automotive oil pump is extremely sensitive to speed, temperature and pressure. The optimum arrangement is a balance between all these factors and Flowmaster enables MPT to calculate the best configuration quickly and easily.
By using Flowmaster to optimise the engine cooling, inter-cooling and exhaust gas recirculation (EGR) systems the concept vehicle installation requirements have been met such that the powertrain’s overall fuel economy savings and emissions reductions can be maximised.
Robert Corbishley, Senior Analysis Engineer for MPT explains how Flowmaster has aided the development process. “Flowmaster shortens the time frame and provides much more detailed information at an early stage. We are able to foresee any potential problems with the engine design much earlier, which saves considerable time and resource. The value for money Flowmaster offers is exceptional, being used throughout the development process. When you evaluate Flowmaster’s contribution to the overall project in time saving versus cost, the return on investment is excellent.”