The transportation sector plays a significant role in environmental pollution and energy consumption, and efforts to reduce its environmental impact are ongoing. Biodiesel, a renewable and sustainable alternative to conventional diesel fuel, has gained attention as a potential solution. In addition to biodiesel, plastic waste can be converted into a usable fuel source, contributing to waste management and reducing the reliance on fossil fuels. The experimental setup includes a single-cylinder VCR engine equipped with a common rail injection system, where injection angles are varied within a specified range. The fuel used in this study is a blend of biodiesel and plastic oil, with a composition optimized for engine compatibility and emissions control. Engine performance parameters, such as brake specific fuel consumption (BSFC), thermal efficiency, and emissions (NO<inf>x</inf>, CO, and particulate matter), are evaluated at different injection angles. This research contributes to the ongoing efforts to enhance the sustainability of the transportation sector by exploring innovative fuel sources and optimizing engine parameters. The results of this study can help guide future developments in VCR engine technology and the utilization of waste plastics as a valuable resource for fuel production. © 2025 Elsevier B.V., All rights reserved.