Recent changes in US and European legislation provide new emissions guidelines designed to simultaneously reduce NO₂ and PM. While the initial focus is on new vehicles, regulatory bodies such as the US Environmental Protection Agency (EPA), California Air Resources Board (CARB), TERC and TCEQ have recognized the need to develop more advanced emission reduction solutions for the retrofit market.

The HARC grant enables Clean Diesel to effectively integrate proven intellectual property widely used by global engine OEMs to a wide variety of retrofit applications. The Purifier e5 system will feature Clean Diesel’s Airless Reagent Injection System (ARIS) selective catalytic reduction (SCR) technology combined with an enhanced diesel particulate filtration and regeneration system based on the Purifier e4 DPF platform.

Clean Diesel’s ARIS system features a single-fluid return flow solenoid-actuated injector. The return flow design with integral cooling allows airless injection of reagents in high-temperature environments such as exhaust streams. ARIS offers precise injection control and good atomization, and the single fluid, return flow design is not prone to injector clogging. The airless nature eliminates the requirement, installation issues and costs of compressed air for traditional air-assisted injection.

The combination of these two proven systems will result in an EPA verified, cost-effective and reliable NO_x and PM reduction solution. In this project, Clean Diesel will develop both open loop and closed loop controls of airless injection, allowing a higher level of emission reduction over a wider range of vehicles with which to serve a larger number of markets.

This project is an important addition to the current NTRD program portfolio. We would like to see more advanced technologies, such as those being used in OEM applications nowadays, and comprehensive approaches which address all regulated emissions effectively at the same time, being adopted for the retrofit market.

—Dr. Yiqun Huang, program director of NTRD at HARC

Clean Diesel develops and manages intellectual property from original concept to full-scale commercial deployment. Building on its almost 300 granted and pending patents, its offerings include ARIS selective catalytic reduction (SCR); the patented combination of SCR and exhaust gas recirculation (EGR); hydrocarbon injection for emissions control applications; Platinum Plus Fuel-Borne Catalyst (FBC); the Purifier family of particulate filter systems; and its wire mesh filter particulate filter technologies. The company was founded in 1995 and is headquartered in Bridgeport, Connecticut.