Three interdependent components are discussed as the basis for a clean diesel system; the use of ULSD fuel which not only greatly reduces sulphur emissions but can also reduce particulate matter by up to 10 percent; new engine technology with redesigned combustion chambers, common rail fuel injection systems and variable geometry turbos that greatly reduces particulate matter and NOx emissions; and emissions control technologies including diesel oxidation catalysts, selective catalytic reduction devices, lean NOx catalysts, exhaust gas recirculation, and active diesel particulate filters. When combined, these three components usher in a new era of clean diesels which emit 98 percent less particulate matter and NOx in 2007 models than 1988 levels.
For existing diesel vehicle owners, the five Rs of retrofitting are also discussed; Rebuild core engine components every three to four years; Refuel using ULSD and/or biodiesel; Retrofit exhaust emissions control technologies; Repower older engines with new or newer diesel engines; and Replace entire old, heavily emitting vehicles and equipment with new models. Sections on Implementation Criteria for successful retrofitting projects, Incentives And Funding Resources, and Sample Retrofit Projects rounds out the paper.
Hopefully large diesel fleet owners will take heed of the advice offered in this white paper and look at implementing their own retrofitting projects to improve the emissions output of the dirtiest diesels on and off the road today.