Turbocharger Aero-thermal Design Optimisation under Realistic Engine Conditions for Low Carbon Vehicles

Air charging systems are widely used in both passenger and commercial vehicle applications to increase power density and improve fuel economy leading to significant emissions reductions. The development of turbochargers to the current state-of-the-art has been of primary importance in enabling the automotive industry to cope with the ever stringent emissions regulations and the scope for improvement remains significant. Although investment in turbocharger technology has made it possible to overcome issues related to reliability and cost, research is much needed in the area of design, testing methodologies and model development. Computational codes are used by engine manufacturers to predict the performance and size of turbomachinery components; prediction accuracy is crucial in this process. The physical phenomena of primary interest in recent turbocharger research include those related to turbocharger aerodynamics and heat transfer. Specifically, the effects of on-engine pulsating exhaust gas flow, turbocharger heat transfer and wide turbine mapping will be investigated. The aims of this project include the characterisation of the interaction of these important but unaccounted for (by the preliminary turbocharger design process) turbocharger aero-thermal flow phenomena in a realistic (on-engine) environment and the delivery of design tools to better inform and therefore accelerate the preliminary design cycle of turbochargers by incorporating design methodologies that integrate the above effects.

The potential beneficiaries of this project may be grouped in the following categories: industrial, economic, environmental and societal and academic/scientific.

The internal combustion engine and turbocharger are devices used in not just the automotive but also the marine and power generation industries. Their contribution to cumulative CO2 emissions forms a substantial part of the total CO2 emissions both in the UK and globally. At present, turbocharging/supercharging is considered as the highest impact technology among the technological options available for the improvement of internal combustion engines (up to 15% improvement in thermal efficiency). Furthermore, the marine, locomotive and industrial power generation sectors also use supercharging/turbocharging and power/waste heat recovery turbine systems widely and the potential impact of this project can, therefore, impact upon a much wider scope of application of turbomachinery. Successful delivery of this project will enable manufacturers to accelerate innovation and the development of new turbocharger products thereby reducing development costs and making them more competitive.In the primary area of interest - the automotive industry - turbocharger growth is set to increase quite dramatically especially in regions of low market uptake such as the US and China. The scope therefore, for substantial contribution to environmental sustainability is open and will arise as a result of (1) small, yet significant engine/turbocharger efficiency improvements, (2) faster market uptake and (3) a substantial, projected increase in the volume of turbochargers produced in the following years.

The above outlook of the turbocharger market and the potential impact of improvements to be brought about by application of improved methodologies such as those developed within the scope of this project, could also lead by default to impact in the society and to the economy. Improvements to air quality, will follow improvements in engine(/turbocharger) efficiency and a larger and more timely market volume increase of improved efficiency engines (through acceleration of the turbocharger design process) will result in further positive impact.

In economic terms, improvements in efficiency coupled with accelerated time-to-market will translate to lower vehicle operating costs without the higher, initial up-front cost of purchase associated with the more expensive developments of new turbomachinery components: these impacts will arise as a result of improved processes leading to improved designs thus incurring practically no additional premium to the cost of acquisition of a new vehicle. The proposed methodological improvements to engineering processes leading to improved engines and faster component design cycles will impact on the competitiveness of UK manufacturers through incorporation of this additional knowledge within their design processes thereby resulting in a more competitive time-to-market thus allowing for the capturing of an increased market share.

Academic and industrial beneficiaries of the proposed research will benefit from the extension of the field of fundamental knowledge in perhaps the most prominent low carbon-enabling technology for ICEs. Other researchers in Academia, research organisations and turbochargers manufacturers will be kept informed through presentations to be given in seminars and conferences organised each year by the IMechE, SAE and ASME and the Universities Internal Combustion Engines Group (UnICEG). Furthermore, the project results will be submitted to at least two international conferences and to relevant international journals; this will ensure archival value of the research and further dissemination will be achieved. Expected deliverables in terms of research output are highlighted in the attached workplan.