Final Activity Report Summary - ENGINE EFFICIENCY (Fluid Interactions for Engine Efficiency) This project sought improvements in fuel and lubricant technology to both increase the efficiency of existing engines and enable the introduction of new, yet more efficient engine concepts. Although the main phase of the projects ran between 2007-2010 the collaborations remain active with Shell financing the researchers' reintegration year. The Fuel related projects focused on Partially Premixed Compression Ignition (PPCI) combustion schemes. Significant success was achieved by the fellow from Lund University in extending the range of PCCI operation for a light-duty diesel engine. By using gasoline type fuels that are resistant to auto-ignition a more optimum distribution of fuel and air in the cylinder prior to autoignition could be obtained. This work led to six papers being published. In a related project a fellow from Imperial College London demonstrated PPCI operation in a multicylinder V6 Lion diesel engine. By extending the measurements to this more realistic environment and studying the impact of EGR, injection strategy and reducing injection pressures further credibility was given to this approach for achieving lower brake specific fuel consumption as well as extremely low smoke and NOx. In addition an optical engine was setup and ran with fuels of differing ignition qualities to explore how auto-ignition quality affects the combustions modes present. The fellow is currently using his integration year to apply laser diagnostics in this optical engine to help ground the growing theoretical understanding of PPCI combustion by providing direct in-cylinder measurements. The fellow from the University of Eindhoven has been studying the fundamentals of PPCI combustion using computational modeling. He applied a Flamelet Generated Manifold (FGM) method developed at the University of Eindhoven. A suitable chemical kinetic model, developed by a previous Marie Curie fellow at Shell, was used to build a table of reaction rate and species mass fraction as a function of mixture fraction and reaction progress variable. By including auto ignition delay time as part of the FGM table, and by using the so-called Livengood Wu integral, this enabled a prediction of where and when autoignition will occur in the system. Computational results were found to be in qualitative agreement with experimental data generated using a model diesel fuel sprayed into a constant volume chamber at the Shell Technology Centre Thornton. The work has been accepted for presentation at two conferences with Journal publications planned. The lubricant related projects addressed improving the understanding of losses under two extreme types of contacts. The fellow from Leeds used finite element analysis to model elastohydrodynamic lubrication which occurs in highly loaded contacts, such as gears. Under the high pressures the lubricant viscosity increases many orders of magnitude and the surfaces deform elastically. Despite the traditional difficulty in modelling elastohydrodynamic contacts the fellow succeeded in modelling line and point contacts for both steady state and transient conditions. The Fellow has presented their work at a conference and submitted for publication. The fellow from Trinity College Dublin studied additives that reduce friction in thin oil films. She used tribology equipment within Shell to better understand the interaction between these friction modifying additives and anti-wear additives that compete for the space on surfaces. The Fellow gave a presentation on this work at the International Additives 2009 conference held in York and a paper based on this work is in the process of being submitted to a tribology journal. Both of these projects will help us to design lubricants which give reduced friction, thus helping to contribute to improved efficiency.
