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In view of CO2 reduction, aimed to mitigate global warming, Fuel Economy (FE) is gaining a primary role in new specifications for engine lubricating oils. Not only oil rheological properties and friction reducer additives, but also all the components of the formulation, such as basestocks, viscosity modifier and additive package, are involved in achieving FE performances. Tribological tests were carried out in our labs to investigate the effect of detergent additives: in particular, the positive role of detergents based on Calcium salts ofcalixarenes, cyclic oligomers obtained from reaction of p-functionalized phenols with formaldehyde, emerged. This type of additives is particularly suitable for modern lubricants preserving aftertreatment efficiency as they are sulfur-free.

A test procedure was set up in our laboratories to evaluate the propensity of fuels and lubricating oils towards the soot accumulation in Diesel Particulate Filters. The experimental work was carried out with the use of a passenger car diesel engine, retrofitted with an aftertreatment system composed by an oxidation catalyst and a DPF. The soot propensity was evaluated by means of repeated measurements of differential exhaust backpressure gradient, during a running period at mid load and speed. The specific fuel consumption gradient was also measured to find a correlation between both the variables. After each soot loading period, a burning off period at full load was operated for the purpose of filter regeneration. A two-phase experiment was undertaken to assess repeatability and discrimination capability of the test procedure. During the first experimental phase, repeated tests were conducted on a fuel matrix containing some surrogate fuels.

Low and ultra low viscosity oils are one of the main solutions considered in view of the improvement of energy efficiency for better fuel economy. The recent modification of SAE J300 engine oil viscosity classification, to include engine oils with high temperature & high shear rate (HTHS) viscosity of 2.3 mPa·s for the SAE 16 grade, has opened debate on the possible real benefits that could derive, in terms of fuel economy and CO2 emission reduction, from the use of ultra low viscosity oils on engines of current technology. Two European compact cars (C-segment) of recent technology and similar characteristics were employed in our laboratories, on chassis-dyno test bed, to evaluate fuel economy with the use of oils having an HTHS viscosity decreasing from 2.9 to 2.0 mPa·s, with a −0.3 mPa·s step.

Climate change demands urgent actions towards CO2 emission reduction. Through their effect on friction losses, new engine lubricants play a key role in reducing fuel consumption and, consequently, CO2 emissions. Besides oil viscosity optimization, friction contributions are primarily dependent on friction reducer (FR) chemistry, although secondary impacts exist for detergent, dispersant, and antiwear additives. The authors have been working for several years in the development of innovative friction reducer additives as well as in the definition of testing methods for evaluating the performances of a large number of molecules and selecting the most promising ones for engine or vehicle tests.