California Air Resources Board

Please join us for a comprehensive characterization of criteria and non-criteria pollutants of two Tier 4 Final off-road diesel engines

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Given the ongoing air quality challenges in California, there has been significant interest extending the efforts of recent on-highway Low NO_x technology demonstration efforts into the off-road sector.  Off-road engines account for 11 percent of statewide NO_x emissions and 29 percent of statewide diesel PM emissions.  This study tested two Tier 4 final off-road diesel engines with similar power ratings but different aftertreatment configurations: one with DPF+SCR and one with SCR only. Both engines showed NO_x emissions levels at less than half the current standards over certification cycles.  PM for the SCR-only engine was at about half the standard, while the DPF+SCR engine was an order of magnitude below the standard. Chemical analyses on gaseous and particulate pollutants indicated good control of unregulated emission species (e.g., VOCs, polycyclic aromatic hydrocarbons (PAHs), metals, etc.) from both engines.  However, poor emission control was observed during unregulated low load operation where NO_x emissions were more than 3 to 4 times higher than the regulatory emission standards. Computer simulation results indicated that NO_x emissions from off-road diesel engines could be substantially reduced using conventional and advanced DPF+SCR systems that are available in the market for on-highway diesel engines. The results from this program will be the foundation for the subsequent effort of demonstrating low emission off-road diesel engine and aftertreatment pathways.

Speaker Biography

Mr. Sharp is an Institute Engineer in the Diesel Engine and Emissions R & D Department at Southwest Research Institute.  He received his bachelor’s degree in Mechanical Engineering from the University of Michigan in 1990, and he has been at SwRI for the past 30 years, where he has been involved in numerous programs related to integration of advanced aftertreatment systems on diesel and natural gas engines, for both on-highway and nonroad engines.  These programs have ranged from early technology and prototype demonstrations, to production development and calibration efforts.  In addition, he also has a strong focus on measurement methodology, and is involved in the development of methods and procedures to characterize low level emissions from advanced technology engines.  He is currently leading program efforts, under way at SwRI since 2014, to demonstrate technologies for achieving very low heavy-duty on-highway and nonroad tailpipe NOx emission levels.