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Legislations aimed at reducing CO2 emissions are driving significant changes in passenger car engine hardware and lubricants. Gasoline direct injection (GDI) engines generate combustion soot which can drive wear which is characteristically different to that observed in diesel engines. The increasing market share of GDI engines has encouraged the auto OEMs and the oil suppliers to study this challenge in more depth and seek improvements which do not compromise the innate efficiency benefits of the GDI platform. This study compares soot abrasiveness by measuring the abrasive removal of Zinc dialkyldithiophosphate (ZDDP) antiwear films and resultant wear by GDI sooted oils and traditional Diesel sooted oils in the MTM-SLIM equipment. A three-way correlation has been developed between a carbon black soot surrogate, GDI sooted oils and Diesel sooted oils.

It is anticipated that worldwide energy demand will approximately double by 2050, whilst at the same time, CO2 emissions need to be halved. Therefore, there is increasing pressure to improve the efficiency of all machines, with great focus on improving the fuel efficiency of passenger cars. The use of downsized, boosted, gasoline engines, can lead to exceptional fuel economy, and on a well-to-wheels basis, can give similar CO2 emissions to electric vehicles (depending, of course, on how the electricity is generated). In this paper, the development of a low weight concept car is reported. The car is equipped with a three-cylinder 0.66 litre gasoline engine, and has achieved over 100 miles per imperial gallon, in real world driving conditions.

Worldwide, Fuel Economy (FE) legislation increasingly influences vehicle and engine design, and drives friction reduction. The link between lubricant formulation and mechanical friction is complex and depends on engine component design and test cycle. This Motored Friction Tear Down (MFTD) study characterizes the friction within a 3.6L V6 engine under operating conditions and lubricant choices relevant to the legislated FE cycles. The high-fidelity MFTD results presented indicate that the engine is a low-friction engine tolerant of low viscosity oils. Experiments spanned four groups of engine hardware (reciprocating, crankshaft, valvetrain, oil pump), five lubricants (four candidates referenced against an SAE 0W-20) and five temperature regimes. The candidate lubricants explored the impact of base oil viscosity, viscosity modifier (VM) and friction modifier (FM) content.

Legislation aimed at reducing carbon dioxide emissions is forcing significant changes in passenger car engine hardware and lubricants. Reduced viscosity lubricants can reduce friction levels and are therefore helpful to manufacturers seeking legislative compliance. MAHLE and Shell have worked together to determine the crankshaft, bearing and lubricant combination which minimizes friction with an acceptable level of durability. This paper describes the results of our joint simulation studies. MAHLE Engine Systems have developed in-house simulation packages to predict bearing lubrication performance. SABRE-M is a “routine” simulation tool based on the mobility method [1] curve fitting from the finite bearing theory to simulate the hydrodynamic lubrication in steady-state conditions. Whereas, SABRE-TEHL is a specialized simulation package used for performing Thermo-Elasto-Hydrodynamic Lubrication (TEHL) analysis of bearing systems.