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Major share of Small Commercial Vehicles (SCV) applications is operated in city conditions with frequent stops and short driving distance. Drivers will often operate these SCV with loads that exceed their rated specifications. Such driving profiles are particularly observed in food, e-commerce delivery, garbage collection vehicles which are driven inside the city. During Diesel Particulate Filter (DPF) regeneration events in these conditions, it is a challenge to maintain light-off temperature of oxidation catalyst. This may lead to prolonged regeneration durations with multiple regeneration interrupts and poor regeneration efficiency. Frequent engine start operations and lower passive regeneration result in a low regeneration interval. The extended DPF regeneration duration in combination with a low regeneration interval will result in high oil dilution. The study focuses on identifying such driving profiles and defining counter measures to improve the regeneration performance.

Fuel entry into oil sump dilutes oil and affects its tribological properties, leading to increased engine wear and failure. Higher oil levels can also lead to uncontrolled combustion and unintended vehicle acceleration. In modern BS6 Diesel engines equipped with Diesel Particulate Filters (DPF), the late post injections are a major source of oil dilution. Other sources of fuel in oil dilution are pump failure and improper geometric sealing of moving parts. In vehicles with NOx Storage Catalyst (NSC) installed, the rich mode would also have a high share in the oil dilution. The SAE paper addresses ways to reduce fuel entry rate from post-injections without compromising the DPF performance. The accumulated soot is regenerated at high exhaust temperature. The high exhaust temperature is achieved by introducing late post injections (PoI1) continuously throughout the regeneration duration (approximately 20 to 30 mins).