Design and Simulation Analysis of Diesel-Battery Hybrid Trains for Intercity Mass Transportation

Diesel Electric Multiple Units (DEMUs) operating on non-electrified networks in rural areas often face challenges regarding noise levels and carbon emissions. Furthermore, standard DEMUs have a significant environmental impact due to the absence of regenerative braking. To solve these issues, an innovative standard DEMUs integrated with a battery system has been developed to effectively reduce fuel consumption and greenhouse gas emissions. This study analyzes the impact of energy management strategies and the calculation of engine and battery capacities in a Hybrid Diesel-Battery train. The calculation of engine and battery capacities must be conducted with high precision to achieve an optimal balance between the weight of the propulsion system and the passenger payload, ensuring that the total mass does not exceed the permissible axle load. The maximum load comprising both traction and auxiliary loads was calculated based on the steepest gradients and operational speeds of the specific route. Based on simulation results, five proposed energy management control conditions achieved a 10.8% reduction in fuel consumption compared to standard DEMUs. Additionally, the study identifies suitable battery specifications based on maximum travel distance and available spatial constraints on the train. Simulations demonstrate that in hybrid mode, covering a round trip distance of 700 km, the system optimally utilizes two 200 kW engines and a 250 kWh battery capacity.