Nitrogen oxides concentrations and heat release characteristics of the Perkins 1104D-E44TA dual-fuel engine running with natural gas and diesel

In the near future, natural gas may become a fuel, which will see increased use in powering internal combustion engines. Due to its properties, it can be used to power spark-ignition engines without major obstacles. Yet using natural gas to power compression-ignition engines proves to be more difficult. One of the possibilities are the dual-fuel compression-ignition engines running with gas fuel and diesel fuel, enabling ignition through compression and combustion of gas fuel. The article presents the heat release characteristics of the Perkins 1104D-E44TA engine powered by compressed natural gas and diesel fuel. Characteristics of heat release are an image of the combustion process. They affect the engine performance indicators. The determined heat release characteristics for a dual-fuel-powered engine were compared with the heat release characteristics for a diesel engine under the same operating conditions. An analysis of heat release characteristics was carried in the scope of their influence on the concentration of nitrogen oxides in the exhaust of the tested engine. The effect of the relative amount of heat released and the heat release rate during the combustion process in the Perkins 1104D-E44TA engine cylinder running dual-fuel with CNG+diesel on the concentration of nitrogen oxides in the exhaust, as compared to the values measured when running with diesel fuel only, was demonstrated. Higher share of natural gas in the total amount of energy supplied to the engine cylinders results in greater differences in the course of the combustion process and result in a greater reduction in the concentration of nitrogen oxides in the exhaust of the tested engine