SBIR Phase II: Development of a Stoichiometric, Direct-Injected, Soot-Free Engine for Heavy-Duty Applications

Diesel engines remain critical to global economies, but are under threat from increasingly-stringent emissions regulations. Many alternatives, like spark-ignition and electric vehicles, sacrifice some of the performance or range benefits of Diesel-style operation. This creates a market need for technologies that can maintain Diesel engine performance while remaining decoupled from the dirty emissions of Diesel fuel. This proposal centers on the development of the ?ClearFlame Combustion System? (CFCS): a novel combustion process that enables Diesel-style engines to combust low-carbon alternative fuels like ethanol and methanol without sacrificing the power possible with traditional Diesel combustion. Further, the sootless nature of alternative fuels such as methanol and ethanol obviates the need for a Diesel particulate filter, and enables stoichiometric air-fuel ratios to eliminate the need for selective catalytic reduction of NOx (smog). The engine technology has the potential to alter the dynamics of any market dominated by Diesel engines (including heavy-duty transportation, agriculture, rail, and power generation) and can be licensed to, or jointly developed with, OEMs for simple integration into their existing product lines. Phase I results have shown a 30% increase in engine torque at increased efficiency, while engine-out soot emissions are more than 100x lower than that of Diesel engines, falling under the 2010 EPA regulation limit without aftertreatment. This Small Business Innovation Research Phase II project will continue development of the CFCS. The Phase I results showed that three critical CFCS subsystems?engine insulation, alcohol direct injection, and a combustion chamber optimized for stoichiometric combustion with exhaust gas load control?could be developed and integrated to achieve a previously unattainable combination of strong performance and low emissions. This Phase II effort will further advance these key components and demonstrate the benefits of the CFCS on a commercial engine platform, using CFD modeling and engine experiments to show the advantages of the CFCS compared to the Diesel baseline. The goal is to show how the CFCS enables a multi-cylinder heavy-duty engine to simultaneously improve power density by 30% at no loss of efficiency, while also achieving sootless stoichiometric exhaust conditions that are compatible with low-cost and highly-effective three-way catalysis (the same system that enables gasoline and natural gas engines to be much cleaner than Diesel). A Phase II prototype demonstration would realize a longtime industry goal of integrating three-way catalysis with a Diesel-style engine, allowing Diesel-style engines to achieve the emissions profile of the cleanest alternatives (like natural gas). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.