Demonstrate Diesel Engine Combustion Using Ammonia as an Alternative Fuel

Grant # 06S-02
Principal Investigator: Song-Charng Kong
Organization: Iowa State University
Technical Area: Renewable Energy

Final Report – Public Abstract

In this project, we proposed to demonstrate the feasibility of ammonia combustion in diesel engines. Combustion of ammonia alone does not produce carbon dioxide which is the most important greenhouse gas. Thus, using ammonia to replace diesel fuel is very attractive in sequestrating greenhouse gas emissions and alleviating global warming. Our approach is to introduce ammonia into the intake manifold (after the turbo, before the cylinder) and use diesel fuel, which was directly injected into the cylinder, to ignite the mixture. This “dual-fuel” approach was chosen because ammonia has a high resistance to autoignition. This approach was proven successful and only required minor modifications to the engine intake system.

We have successfully demonstrated ammonia combustion in diesel engines. Engine tests were performed on a multi-cylinder, turbocharged diesel engine manufactured by John Deere (Model 4045). The intake system of the engine was slightly modified to integrate with the ammonia fuel line, whereas the diesel fuel injection system remained unchanged. Liquid ammonia tank was installed and a high pressure relief valve was used to regulate the ammonia flow rate. Combustion phasing (e.g., ignition) was controlled by diesel fuel injection. Extensive experiments and chemical kinetics study were carried out for different diesel/ammonia ratios at various engine speeds and loads. The energy replacement by ammonia can be as high as 95 percent. C02 emissions can be reduced for the same amount of engine power output. A lower level of NOx emissions can be also obtained if the energy substitution by ammonia does not exceed 60 percent.