Advancing Sustainable Practical Engineering Education: A Closed-Loop VR-Blended Learning System for Diesel Engine Assembly Training and Assessment

Traditional engineering practical education faces high equipment expenditure, limited hands-on practice, material-resource consumption, and inequitable access to high-quality training, impeding progress toward UN SDG 4 (Quality Education) and SDG 9 (Industry, Innovation, and Infrastructure). To address these bottlenecks, this paper constructs a closed-loop desktop VR-blended learning system (VBLS) for diesel engine assembly using Unity3D and high-fidelity 3D models of seven core engine subsystems. Guided by experiential learning and cognitive load theories, the platform supports pre-lab structural preview, dual-mode assembly, and post-training online knowledge assessment. An exploratory post-test comparison was conducted between two intact classes (n = 30 per class): one class used VR-blended teaching and the other received conventional lab instruction. The blended group achieved a numerically higher average score (81.47 vs. 77.83) with a moderate effect size (Cohen‘s d = 0.48), 95% CI [−0.33, 7.61], with 63% scoring above 80 versus 43% in the control group. Questionnaire feedback (n = 30) from the blended-teaching group showed satisfactory usability, self-reported learning engagement, and students’ self-perceived raised awareness of sustainable engineering practices. Although virtual simulation avoids engine-related component wear and physical consumable use, these sustainability advantages stem from system design and require further empirical validation. Given experimental limitations, this study provides a replicable simulation-based prototype with prospective value for sustainable engineering education through lower training expenditure and improved accessibility.