Modelling lubrication oil particle emissions from heavy-duty diesel engines

Abstract

The impact of lubrication oil on particle exhaust emissions has attracted increasing attention as emissions of fuel-derived particles have been reduced. This paper presents a model for assessing the oil-related exhaust particle emissions of heavy-duty diesel engines. The model contains four sub-models describing the hydrocarbon, ash, carbon and sulphate particles. All sub-models were developed based on the results of a literature review, complemented by controlled engine tests to fill the knowledge gaps and verify assumptions where necessary. Exhaust after-treatment devices, such as diesel particulate filters, are not included in the model at this stage; in engines equipped with such devices, the modelling results could be used to assess the input of oil-related particulate matter into the exhaust after-treatment system or serve as a basis for further development. The modelling results indicate that the contribution of oil to airborne exhaust particles is substantial under low-load and motoring conditions. Reducing oil consumption is an effective way to reduce oil-related particle emissions.