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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.

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.

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.

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.