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Gaseous and particulate matter (PM) emissions were assessed from two current technology heavy-duty vehicles operated on CARB ultra-low sulfur diesel (ULSD), hydrotreated vegetable oil (HVO) blends, and a biodiesel blend. Testing was performed on a 2014 model year Cummins ISX15 vehicle and on a 2010 model year Cummins ISB6.7 vehicle. Both vehicles were equipped with diesel oxidation catalysts (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR) systems. Testing was conducted over the Heavy-Duty Urban Dynamometer Driving Schedule (UDDS) and Heavy Heavy-Duty Diesel Truck (HHDDT) Transient Cycle. The results showed lower total hydrocarbons (THC), non-methane hydrocarbons (NMHC), and methane (CH4) emissions for the HVO fuels and the biodiesel blend compared to CARB ULSD. Overall, nitrogen oxide (NOx) emissions showed discordant results, with both increases and decreases for the HVO fuels.

The sulphur level of diesel fuels began to be limited in Europe at the end the 20th century. Quite soon after that it was noticed that the processes for removing sulphur also removed other polar compounds and the natural lubricity of the diesel fuel was lost. Lubricity additives were introduced to restore lubricity properties. Also, a rapid laboratory method was developed to measure lubricity i.e. High Frequency Reciprocating Rig (HFRR). The method (HFRR) ISO 12156-1 was introduced in 1997 and included in EN 590. In recent years purely paraffinic diesel fuels, such as GTL (Gas To Liquid) and renewable HVO (Hydrotreated Vegetable Oil), have been introduced to the market. Unlike traditional biodiesel (FAME, Fatty Acid Methyl Ester), paraffinic diesel fuels require the use of lubricity additives to reach a sufficiently high level of lubricity.