Results of recurrent in-service exhaust gas measurements with an EU stage IV forest harvester fuelled with rapeseed oil within the emission durability period

Abstract

The real driving emissions of an EU stage IV forest harvester were measured four times within five years to monitor long-time emission behaviour. In this period, the harvester worked 7650 h in total, thereof 6300 h with pure rapeseed oil fuel DIN 51605 (R100) and 1350 h with conventional diesel fuel initially. Data analysis according to relevant EU regulation 2017/655 shows that the emission behaviour complies with the legal requirements of exhaust gas stage IV within the five years under consideration. According to EU regulation 2016/1628 the achieved 7650 operating hours nearly correspond to the emission durability period of 8000 h. However, between the single measurements some differences in emission results are clear evident. They are primarily caused by different working profiles, and unavoidable random events. Detailed analysis of the results showed that the measured nitrogen oxides (NOX), carbon monoxide, and hydrocarbons remain at the same level over time at comparable operation conditions. Thus, the operation time had no major impact on the emission behaviour of the harvester. During cold start and non-working events higher nitrogen oxides (NOX) concentrations are observed in the exhaust since the exhaust aftertreatment system is not within its operation temperature. When the exhaust gas aftertreatment is within its operating range, exhaust emissions are at a very low level indicating an efficient, clean combustion. It can be concluded that the operation of the harvester with R100 did not affect the emission behaviour and functionality of the exhaust gas aftertreatment system.