**Abstract**

Through an experimental study, this work focused on finding the influence of exhaust gas recirculation (EGR) on waste plastic pyrolysis oils (WPPOs) with diesel as a base comparison fuel. The results show the amount of carbon monoxide emissions seemed to decrease at low engine loads up to intermediate loads of (50%), thereafter continued to increase significantly but marginally. Among fuels tested, blend WPPOB100 reported the highest BSFC, at 0% EGR flow rate. The value was 0.4751g/kW.hr. compared with 0.7235 g/kW.hr. at 30% EGR flow rate. Increased blend ratio had a direct decrease in brake power linearly. At 30% engine load, CD, WPPOB10, WPPOB20, WPPOB30 and WPPOB40 recorded values of 2.125 kW, 2.15 kW, 2.05 kW, 1.98 kW, 1.86 kW and 1.75 kW, respectively. Exhaust gas temperature (EGT) at 30% EGR flow rate, blend WPPOB10 had the highest reduction in temperature compared with the any other WPPO blends at 320°C. Increased blend ratio and EGR percentage flow rate increased smoke emissions within the test fuels blends. At 15% EGR flow rate, the following data were recorded: 7.53%, 7.1%, 6.72%, 6.25%, 6.0% and 5.4% for CD, WWPO10, WPPO20, WPPO30, WPPO40 and WPPO100, respectively.

**Keywords:** biodiesel, CO2, UHC, CO, conventional diesel, EGR flow rate, NOX, smoke emissions, waste pyrolysis plastic oil
