Experimental investigation of performance, combustion and emission characteristics of a variable compression ratio engine using low-density plastic pyrolyzed oil and diesel fuel blends

Abstract

Plastic waste adversely affects millions of people and wildlife habitat in many parts of the world. Although it could be utilized as a promising source of alternative fuel, its progress is not as advance as biodiesel or bio-alcohol. Accordingly, a base fuel (BF) was blended with plastic pyrolyzed oil (PPO) to comprehensively investigate the usability of this product as a fuel substitute in compression ignition engines. Three fuels, BF100PPO0, BF80PPO20, and BF0PPO100, were tested and compared in a single-cylinder, 4-stroke, water-cooled VCR DI-CI engine that ran at five different compression ratios (15.5, 16.5, 17.5, 18.5, 19.5) under low, medium, and high engine loads. In the results, it is noticed that except for the maximum rate of pressure rise and ignition delay, raising the compression ratio from 15.5 to 19.5 did not result in significant changes. The results showed that BF80PPO20 produced the maximum BTE (34.4 percent) at CR 15.5 under high engine load, while BF100PPO0 produced the lowest BSFC (738.29 g/kWh) at CR 16.5 under high load. In terms of emissions, CO2 levels were found to be essentially same for all tested fuels at the greatest load for all compression ratios. Furthermore, with CR 19.5, BF80PPO20 was able to produce the lowest smoke emissions at medium load. In addition, at CR 15.5 and low engine load, BF100PPO0 produced the lowest NOx emissions (64.3 ppm). Overall, based on the findings of this research, plastic waste oil mixed with diesel fuel at a rate of up to 20% can be utilised as a promising biofuel to improve diesel engine performance, combustion, and emissions.