Partially premixed charge compression ignition engine with on-board H2 production by exhaust gas fuel reforming of diesel and biodiesel

The application of the exhaust gas fuel reforming process in diesel engines has been studied experimentally as a way to assist the premixed charge compression ignition operation by substituting part of the main fuel with hydrogen-rich gas. The technique involves the injection of hydrocarbon fuel into a catalytic reformer fitted into the exhaust gas recirculation (EGR) system, so that the produced gas mixture is fed back to the engine as reformed EGR (REGR). First, experiments with simulated REGR were conducted with diesel as well as biodiesel as the main engine fuel. Then, experiments with the product gas of a monolith reformer were carried out. In both cases, REGR resulted in a higher premixed combustion rate and reduction of the diffusion combustion phase. The potential of the technique in terms of achieving reduction of smoke and NOx emissions and improved fuel economy has been shown and discussed in the paper.