Rotary Engine Combustion With Hydrogen Addition

The lean operating limit of a rotary combustion engine was extended by hydrogen-enriched fuel to equivalence ratios as low as 0.49. Reductions in NO_x and CO emissions from baseline conditions were observed, although HC emissions increased significantly.

The effect of hydrogen-induced lean combustion on indicated thermal efficiency was found to be dependent on the change in H₂/C₈H₁₈ fraction with decreasing equivalence ratio. An increase in H₂/C₈H₁₈ fraction with decreasing equivalence ratio had little effect on indicated thermal efficiency, whereas a constant or decreasing H₂/C₈H₁₈ fraction led to a marked decrease. The brake thermal efficiency when compared at constant power increased marginally.