The CO emission increases with the increasing WPO blend ratio and engine load. CO emission is higher 0.241 g/kW h at low load to 2.26 g/kW h at high load for 40% B WPO as compared to 0.046 g/kW h at low load to 0.86 g/kW h at full load for diesel. The carbon dioxide emission for the blends is lower than diesel for almost all loads and all blends.