Performance enhancement of a single-cylinder gasoline engine through hydraulic variable valve actuation (HVVA) system integration

This study was conducted to investigate the integration of a Hydraulic Variable Valve Actuation (HVVA) system into a Lifan 177F single-cylinder gasoline engine to enhance performance, fuel efficiency, and emissions control. Unlike conventional valve mechanisms, HVVA systems are designed to dynamically adjust valve timing and lift through hydraulic actuation, allowing combustion to be optimized across a range of engine loads and speeds. MATLAB and GT-Suite simulations were used to model and evaluate the behavior of various valve spring configurations, including single-valve, dual-valve, and double-spring pendulum designs under dynamic operating conditions. It was found that engine power output was increased by 10%, fuel consumption was reduced by 5.64%, and torque delivery was significantly improved at mid to high RPM ranges. Among the configurations examined, the double-spring pendulum mechanism was shown to be the most effective in minimizing hydraulic oscillations, improving valve stability, and enabling smoother operation at higher speeds. These results highlight the practical potential of HVVA systems for use in compact and cost-sensitive engine platforms, where compliance with stringent emissions regulations and improved efficiency are increasingly demanded. Through precise and adaptive valve control, the proposed HVVA approach is shown to support cleaner combustion and align with broader sustainability objectives. In future work, efforts will be directed toward overcoming integration challenges and refining control strategies to further optimize HVVA system performance in practical automotive applications.