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To solve the problems such as braking energy of pure diesel locomotive can only be wasted and pure battery locomotives have low traction power and short cruising range, bidirectional DC/DC circuit of traction battery is integrated into the traction converter in diesel electric hybrid locomotive. To effectively use energy of diesel engine and traction battery, it presents an energy optimal control proposal for diesel electric hybrid locomotive. Under the traction condition, according to the demand power of traction motor and auxiliary load and the current allowable output power of traction battery, it controls the optimal energy supply of diesel generator and traction battery, and gives priority to the use of traction battery to provide energy to load in order to save fuel. Under the braking condition, according to the size of electric braking energy, it gives priority to auxiliary load consumption or traction battery energy recovery. Since the maximum allowable charging current is affected by SOC, temperature and other conditions, this paper introduces the optimal control of electric braking energy under several special conditions. In order to quickly response to complex energy conversion process, bidirectional DC/DC circuit adopts adaptive flexible charge discharge control, which can adaptively select to work in Boost or Buck mode. The judgment method is simpler and more accurate, and can switch to each other safely and flexibly. Test results show that through the optimal energy control, the energy of diesel generator and traction battery can be used reasonably, and the electric braking energy can be recovered effectively, which improves the fuel economy from the load side and significantly improves the energy utilization rate.

The wheel–rail adhesion is one of the key factors limiting the traction performance of railway vehicles. To meet the adhesion optimization needs and rapidly obtain wheel–rail creep characteristics under specific operating conditions, an engineering identification method for wheel–rail adhesion characteristics based on a nonlinear model is proposed. The proposed method, built upon the traditional Teaching-Learning-Based Optimization (TLBO) algorithm, has been adapted to the specific nature of nonlinear wheel–rail adhesion model parameters identification, enhancing both the search speed in the early stages and the search accuracy in the later stages of the algorithm. The proposed identification algorithm is validated using experimental data from the South African 22E dual-flow locomotive. The validation results demonstrate that the proposed identification algorithm can obtain a nonlinear wheel–rail adhesion characteristics model with an average adhesion coefficient error of around 0.01 within 50 iteration steps. These validation results indicate promising prospects for the engineering practice of the proposed algorithm. [ABSTRACT FROM AUTHOR]

To distinguish between the kinetic and chemical contributions in the impact of PTFE/Al, this study explores the feasibility of introducing an inert substitute for PTFE/Al by substituting aluminum (Al) with inert materials. Three specimens were fabricated through a process involving mixing, compression, and sintering of raw materials The mechanical properties of these specimens were assessed. Dynamic fragmentation tests of PTFE/Al and PTFE/LiF specimens were performed. These results further substantiate the potential of PTFE/LiF as an inert alternative to PTFE/Al, the two materials exhibit comparable fragmentation distribution characteristics. A preliminary exploration of the energy release in both materials was conducted via vented chamber calorimetry tests. The findings reveal that, at an impact velocity of roughly 650 m/s, only 66.9 % of the materials were deposited into the chamber, with a mere 17.8 % being initiated, about 88.9 % of the total deposited energy results from the chemical reaction energy within the PTFE/Al materials. Importantly, this method demonstrates promise for further application in energy release analysis experiments for various PTFE/Al‐based reactive materials. These findings are beneficial for evaluating the energy release characteristics of reactive fragments on typical targets and lay the foundation for refining energy release models of such materials in future research. [ABSTRACT FROM AUTHOR]