In order to solve the failure of fuel system when using petroleum coke oil slurry (PCOS) in a R180 diesel engine directly,a petroleum coke oil slurry fuel system (PCOSFS) was developed and installed in R180 engine,which was called PCOS engine.In order to analyze performances and emissions of the PCOS engine,a comparative experiment between PCOS engine fueled with PCOS and R180 engine fueled with diesel oil was carried out.The results show that the PCOS engine can run smoothly,the maximum output power decreases by about 6.2% and 19.0% and the maximum brake thermal efficiency reduces by around 5.85% and 4.13% as compared to R180 engine under the conditions of 1 200 and 1 600 r/min.The HC emissions of PCOS engine are lower than those of R180 engine at 1 200 r/min,and are close to those of R180 engine at 1 600 r/min.The CO emissions are similar to R180 engine at 1 200 and 1 600 r/min.The smoke intensity is close to R180 engine at 1 200 r/min,and is higher than R180 engine at 1 600 r/min.The particles emitted from PCOS engine array sparsely,but particles emitted from R180 engine array closely,cohering together.