Abstract
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•• Developed HCCI Engine powered by waste plastic oil (WPO) and compared with conventional CI engine.•• Inlet air temperature (IAT) and injection pressure (IP) of WPO were optimized for the HCCI engine.•• Increase in IP higher than 10 bar resulted in preignition of the fuel.•• NOx and smoke emissions drastically reduced for HCCI mode as compared to conventional CI engine.•• HCCI engine performance optimized for 90 °C IAT and 8 bar IP.
In the present-day scenario, the regulations over vehicle emissions are highly stringent, and the manufacturers are struggling to satisfy the emission norms. Waste plastic oil (WPO) powered conventional compression ignition (CI) engine discharge higher oxides of nitrogen emission. The utilization of WPO as a sole fuel in homogeneous charge compression ignition (HCCI) engine would satisfy both energy demand and emission norms. The present study demonstrates the effects of different intake air temperatures (IAT) and injection pressures (IP) of WPO on the HCCI engine’s performance and combustion characteristics. The results revealed that the WPO fueled CI engine showed greater BTE when correlated to WPO powered HCCI engine. In the HCCI mode of operation, the elevated IAT led to the advanced start of combustion (SOC). It shortened the combustion due to an increase in post-combustion temperature and cylinder pressure. WPO operated homogeneous charge mode with IAT of 90 °C resulted in better BTE and lesser unburnt hydrocarbon (UBHC), smoke, and carbon monoxide (CO) emission than IAT atmospheric conditions. The HCCI engine with elevated IAT of 80 °C, 90 °C, and 100 °C drastically reduced the NOx emission by 45.5%, 41.9%, and 40.04% than standard CI engine fueled with WPO+- respectively. Among various IPs of WPO, IP of 8 bar revealed 3.08% higher BTE with 11.2%, 16.6%, 14.7% decrease in CO, UBHC, and smoke emission, respectively. At the optimum condition of IP and IAT in the HCCI engine, the BTE was closer to that of the WPO powered CI engine, and also ultra-lean NOx and smoke emissions were noticed.