This Small Business Innovation Research (SBIR) Phase II project will prototype, characterize, and verify performance merits and the commercial viability of an Adaptive Dual-Fuel (ADF) Injector. Diesel engines are 30~40% more efficient than port-injected gasoline, spark-ignited engines. Gasoline and E85 fuels are among the most widely available fuels, but are mostly used on spark-ignition gasoline engines with much lower thermal efficiency than diesel engines. The key innovation of the ADF injector enables direct-injections of both gasoline/E85 and diesel fuel selectively on-demand from a single injector. The ADF injector can enable advanced combustion modes that have demonstrated simultaneous reduction of NOx and Particulate Matter (PM) emissions and improved engine efficiency through advanced low temperature combustion. The advanced combustion mode enabled by the ADF injector can improve the thermal efficiency of gasoline/E85 engines by approximately 30~40% by using gasoline and/or E85 fuels in a compression ignition combustion mode. The adaptive dual-fuel injector also provides flexibility for enabling engines to run on either pure diesel, gasoline-diesel, or E85-diesel dual fuels. The Phase II work includes prototyping, spray visualization imaging and laser based measurements, computational optimization, and single-cylinder engine combustion testing to demonstrate the commercial viability of the proposed ADF injector. <br/><br/><br/>The broader/commercial impacts of this project pertain to significant benefits for energy security and environmental protection. The potential customers include engine OEMs and auto makers. This project will significantly benefit US consumers through fuel cost saving, enable low cost methods to meet the new CAFE standards, and benefit the US economy by expanding the ?green? manufacturing base. The dual fuel injector, developed and analyzed in this work, provides new capabilities, which can enable transformative combustion methods for ultra-high efficiency, clean combustion. The industry-university collaborative engineering research directly support graduate student research and will train and educate the workforce of the future, providing them with the knowledge and skills needed to address the challenges of energy utilization. The research and development efforts, which focus on a critical problem of global importance, will be widely disseminated to engine designers, OEMs, and researchers, while the next generation of engineers is being trained.