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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.

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.

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.

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.

The present work investigates the impact of lubricating oil formulations on efficiency and durability of Diesel particulate filters (DPF) by means of tests on a passenger car diesel engine retrofitted with a continuously regenerating DPF. An accelerated test procedure, characterized by oil injection into the intake air manifold to simulate a higher oil consumption, was designed and used to enhance the oil effect on trap weight increase and exhaust gas backpressure. Different prototype oils, designed to evaluate the influence of key additives characterized by a different elemental content, were used. The accelerated tests revealed to be a good tool to discriminate, in a short time, oils having a different impact on DPF performances. The main role of oil consumption and oil ash content emerged from the tests.

The present work aims at deepening the phenomenon of oil consumption, paying particular attention to the study of oil consumption contribution deriving from turbocharger. In order to evaluate the quantity of oil that leaks from turbocharger oil seals, it was necessary to design a turbocharger lubricating oil system that is totally independent from the main lubricating circuit. The oil consumption from both turbocharger and engine was measured with gravimetric method. A Mercedes OM364LA medium duty Diesel engine was run at maximum power output for more than 300 hours. Different lubricating oils were alternated in order to evaluate the influence of some lubricating oil parameters on oil consumption, while a reference oil was tested at different times to estimate the oil consumption trend during life for both engine and turbocharger.

Deuterated n-paraffins and polyaromatic compounds were added to a reference oil to elucidate its role on the emission of Soluble Organic Compound at diesel exhaust. This work carries on from previous investigations applied to fuel doping with deuterated compounds [1]. Both direct emissions and indirect effects, due to dilution with fuel components and combustion products are investigated. Furthermore the addition of deuterated compounds, is applied to calculate unburned percentage, to study the metabolism of lube oil component and can be applied to measure lube oil consumption. In this paper the results obtained on a light duty and a heavy duty vehicle fuelled with a reference fuel are presented. Particular attention was paid to total particulate and semi volatile phases.

The present work, carried out within the framework of the JOULE-3 European joint project entitled “Fuel and lubricant formulations for high de-polluted engines”, investigates the effect of both the fuel and the lubricating oil quality on deposits, wear and exhaust emissions in the presence of a high EGR rate, with specific attention to the emission variation during aging. Two fuels (a current Italian typical fuel and a Swedish high quality fuel) and two lubricants (a traditional mineral oil SAE 15W-40/ACEA B2 and a full synthetic SAE 0W-40/ACEA B3) were used to carry out six tests, each one characterized by 126-hour duration at different running conditions, on a VM Turbotronic Diesel engine. The engine evaluation pointed out an interaction between oil and fuel: if the high quality fuel (nearly zero S) is used, a low level of cylinder bore polishing and top ring wear, weakly affected by the oil quality, occurs.