Euro 6 European legislation emission limits, expected to be introduced around the 2014 timeframe, Lean NOx Trap (LNT) Aftertreatment technology is today considered one the of candidate technology to allow diesel Engine to meet the future Euro 6 limit.
The working principle of the LNT is based on its capability to store the NOx engine out during the normal lean (excess of Oxygen) phase operation condition of the Diesel engine. The NOx will be then reduced in a dedicated regeneration phase which consist in creating for relatively short time a rich exhaust gas condition inside the LNT.
The LNT regeneration strategy lead to run a Diesel engine with a rich mixture out of the combustion as a Gasoline engine. This can be obtained using advanced air and fuel management. The fuel management implicate the use of delayed injections (after and/or post injections) which can have a direct impact on oil dilution.
In this paper, an experimental assessment of the additional oil dilution phenomenon, potentially introduced by the LNT application, was proposed. The first step of the work was the characterization, in several engine operating conditions, of the NOx storage capacity of the LNT catalyst tested.
The second step was the definition of an oil dilution test procedure for a LNT system that has to take into consideration DPF and LNT regeneration events contribution. The oil dilution was measured by chemical analysis of oil sample (viscosity " 40 °C and 100 °C).