Experimental assessment on the performance, emission and combustion characteristics of a safflower oil fueled CI engine with hydrogen gas enrichment

•Production of biodiesel from safflower to use as an alternate fuel for compression ignition engine.•Improve the performance for safflower oil biodiesel fueled compression ignition engine by hydrogen gas enrichment.•Reduction of smoke, HC and CO except NOx emissions with hydrogen addition.•Improvement in brake thermal efficiency with hydrogen gas enrichment which is limited to 12% energy share.