The increasing global environmental awareness, evidenced by recent worldwide calls for control of climate change and greenhouse emissions, has placed significant new technical mandates for automotives to improve engine efficiency, which is directly related to the production of carbon dioxide, a major greenhouse gas. Reduction of parasitic losses of the vehicle, powertrain and the engine systems is a key component of energy conservation. For engine efficiency improvement, various approaches include improvements in advanced combustion systems, component system design and handling—such as down-sizing, boosting, and electrification—as well as waste heat recovery systems etc. Among these approaches, engine friction reduction is a key and relatively cost-effective approach, which has been receiving significant attention from tribologists and lubricant-lubrication engineers alike. In this paper, the fundamentals of friction specific to the environments of engine components tribology are reviewed, together with discussions on the impact of developing vehicle powertrain technologies, surface and material technologies, as well as lubricant and additive technologies on promises of continuing friction and wear reduction trends. The international accords on climate change require further gains in fuel efficiency and energy sustainability from all industry sectors including those in the automotive and the broader internal combustion engine industries, and the latter encompass off-highway, power generation, marine, and rail industries as well. This paper focsuses on friction reduction in mainly automotive engines, however.

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Overview of automotive engine friction and reduction trends– Effects of surface, material, and lubricant-additive technologies

Simulation of journal bearing friction in severe mixed lubrication – Validation and effect of surface smoothing due to running-in

Cold start driving cycles exhibit an increase in friction losses due to the low temperatures of metal and media compared to normal operating engine conditions. These friction losses are responsible for up to 10% penalty in fuel economy over the official drive cycles like the New European Drive Cycle (NEDC), where the temperature of the oil even at the end of the 1180 s of the drive cycle is below the fully warmed up values of between 100°C and 120°C. At engine oil temperatures below 100°C the water from the blow by condensates and dilutes the engine oil in the oil pan which negatively affects engine wear. Therefore engine oil temperatures above 100°C are desirable to minimize engine wear through blow by condensate. The paper presents a new technique to warm up the engine oil that significantly reduces the friction losses and therefore also reduces the fuel economy penalty during a 22°C cold start NEDC. Chassis dynamometer experiments demonstrated fuel economy improvements of over 7% as well as significant emission reductions by rapidly increasing the oil temperature. Oil temperatures were increased by up to 60°C during certain parts of the NEDC. It is shown how a very simple sensitivity analysis can be used to assess the relative size or efficiency of different heat transfer passes and the resulting fuel economy improvement potential of different heat recovery systems system. Due to its simplicity the method is very fast to use and therefore also very cost effective. The method demonstrated a very good correlation for the fuel consumption within ±1% compared to measurements on a vehicle chassis roll.

/pdf/a-new-method-to-warm-up-lubricating-oil-to-improve-the-fuel-1aoqu51y1z.pdf

A New Method to Warm Up Lubricating Oil to Improve the Fuel Efficiency During Cold Start

Ball bearing skidding and over-skidding in large-scale angular contact ball bearings: Nonlinear dynamic model with thermal effects and experimental results

Edge loading and running-in wear in dynamically loaded journal bearings

Impact of high pressure and shear thinning on journal bearing friction

Oscillatory and steady shear viscosity: The Cox–Merz rule, superposition, and application to EHL friction

Aus Grunden des Umweltschutzes und der Servicefreundlichkeit ist die Automobilindustrie bestrebt, die Olwechsel-intervalle zu optimieren. Im Auftrag der Forschungsvereinigung Verbrennungskraftmaschinen e. V. (FVV) haben drei Forschungspartner in einem gemeinsamen Forschungsprojekt die Schmierstoffalterung und deren Einfluss auf das Verschleisverhalten der Tribosysteme im Ottomotor untersucht. Die Partner sind das Institut fur Tribologie und Energiewandlungsmaschinen der Technischen Universitat Clausthal, das Institut fur Maschinenelemente und Konstruktionstechnik der Universitat Kassel und das Institut fur Oberflachen- und Schichtanalytik GmbH der Technischen Universitat Kaiserslautern.

Ölalterung und Verschleiß im Ottomotor

Die Auswirkung von ethanolhaltigem Kraftstoff auf die Schmierolalterung in Ottomotoren ist bisher kaum untersucht. Das FVV-Forschungsprojekt 930 von TU Clausthal, Universitat Kassel und IFOS Kaiserslautern zeigt auf, dass der Betrieb mit E85 die Lebensdauer des Motors verkurzt. Fur die Steuerkette als Triboleitsystem erhoht sich die Verschleisrate um 20 %.

Auswirkung von Ethanol E85 auf Schmierstoffalterung und Verschleiss im Ottomotor

To meet the needs of industries using high pressure technologies, in traceable, reliable and accurate pressure measurements, a joint research project of the five national metrology institutes and the university was carried out within the European Metrology Research Programme. In particular, finite element methods were established for stress–strain analysis of elastic and nonlinear elastic–plastic deformation, as well as of contact processes in pressure-measuring piston-cylinder assemblies, and high-pressure components at pressures above 1 GPa. New pressure measuring multipliers were developed and characterised, which allow realisation of the pressure scale up to 1.6 GPa. This characterisation is based on research including measurements of material elastic constants by the resonant ultrasound spectroscopy, hardness of materials of high pressure components, density and viscosity of pressure transmitting liquids at pressures up to 1.4 GPa and dimensional measurements on piston-cylinders. A 1.6 GPa pressure system was created for operation of the 1.6 GPa multipliers and calibration of high pressure transducers. A transfer standard for 1.5 GPa pressure range, based on pressure transducers, was built and tested. Herewith, the project developed the capability of measuring pressures up to 1.6 GPa, from which industrial users can calibrate their pressure measurement devices for accurate measurements up to 1.5 GPa.

http://iopscience.iop.org/article/10.1088/1681-7575/aa895a/pdf

Ludwig Brouwer

Papers

Impact of high pressure and shear thinning on journal bearing friction

Oscillatory and steady shear viscosity: The Cox–Merz rule, superposition, and application to EHL friction

Ölalterung und Verschleiß im Ottomotor

Auswirkung von Ethanol E85 auf Schmierstoffalterung und Verschleiss im Ottomotor

High pressure metrology for industrial applications