NOx and PM emissions reduction on an automotive HSDI Diesel engine with water-in-diesel emulsion and EGR: An experimental study

► Experimental study on a HSDI Diesel engine running with water-in-diesel emulsion. ► Volumetric water/fuel ratio of 25.6%. ► Two fuelling-rate strategies combined with exhaust gas recirculation. ► Combustion analysis indicates improvement of the air-fuel mixing process. ► Large improvement of the NOx-PM emissions trade-off.