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Aiming at the problems of incomplete efficiency composition, limitation to single working condition calculation and lack of power loss analysis in the current efficiency model research of hydro-mechanical continuously variable transmission（HMT）, this study establishes a full-condition efficiency model of HMT considering the power loss of transmission components and accessories. Firstly, the general efficiency model of HMT variable pump-quantitative motor is established, and the relevant parameters are recognized according to the efficiency test data; then the efficiency models of other HMT transmission mechanisms and accessories are established, and the complete HMT efficiency model is obtained by combining the efficiency models of each part. Based on the self-developed HMT, the calculation is carried out to obtain the full working condition efficiency map and the loss power of each component mechanism, the test bench is built, and the efficiency test is carried out on the HMT to validate the accuracy of the model, and the average absolute errors of the efficiencies of the HM1 section and the HM2 section under full working condition are 0.027 3 and 0.026 1, respectively, which improve the accuracy of the HM1section and the HM2 section by 64.59% and 55.46% respectively, comparing to the accuracy of the comparative methods. Combined with the efficiency diagram and power loss situation to analyze the HMT efficiency characteristics and influencing factors, the results show that: 1) the HMT efficiency model in this paper is mainly affected by the load and the displacement ratio e of the hydraulic unit, and the influence of the input speed is not significant; 2) the main influencing factors of this paper’s HMT efficiency model are the load under the low load, and the displacement ratio under the high load; 3) the power loss of the pump motor has the greatest influence on the HMT efficiency, and the hydraulic loss power is large when e ＜ 0. The HMT efficiency is low; when e = 0, the hydraulic loss power is 0, and the HMT efficiency reaches the highest; 4) the power loss of gears and clutches does not have a negligible impact on the HMT efficiency, and the consideration of the power loss of other accessories is conducive to the improvement of the modeling accuracy. Measures to improve the efficiency of HMT:1) Try to avoid HMT working under power cycling conditions for a long time, and recommend operating at purely mechanical points and their nearby work points under the premise of prioritizing load demand and ensuring engine economy; 2) Avoid prolonged low load operation, and should be kept in high load conditions; 3) Select high-efficiency hydraulic unit or improve the transmission efficiency of the hydraulic unit by improving the parameters; 4) Improve parameters to reduce power loss under the premise of meeting the performance requirements of gears and clutches. [ABSTRACT FROM AUTHOR]

Cultivation and sowing agricultural machinery equipment plays a pivotal role in influencing the quality and efficiency of cultivation operations across 133 million hectares of arable land in China. The rapid advancement of agricultural mechanization has led to heightened demands for enhanced wear resistance and extended service life of soil-engaging components in cultivation and sowing agricultural machinery, including rotary tillers, plowshares, deep loosening shovels, rake blades, and trenchers. Consequently, there is a paramount need to bolster research efforts aimed at enhancing the surface wear resistance of soil-engaging components in agricultural machinery and equipment. Building upon this premise, this study provides a comprehensive overview of the current research status regarding the enhancement of surface wear resistance in soil-engaging components within agricultural machinery and equipment. Initially, the primary forms of wear and failure in soil-engaging components of agricultural machinery and equipment are elucidated, encompassing abrasive wear, fatigue wear, and corrosion wear. Concurrently, the wear mechanisms of soil-engaging components in agricultural machinery, influenced by external factors such as abrasive particle shape, external load, soil moisture content, and pH value, are delineated, alongside an overview of diverse research methodologies concerning these mechanisms. Subsequently, detailed elaboration is provided on the progress in research and development of surface treatment processes, including surface melting, welding, thermal spraying, laser surface strengthening, chemical heat treatment, and brazing. Furthermore, an exploration and analysis of the disparity in wear resistance and strengthening technology for soil-engaging components between China and foreign nations are conducted from four perspectives: wear mechanism, material research and development, structural design, and manufacturing processes. Although domestic enterprises and researchers have conducted significant research, a noticeable disparity persists between soil-engaging components in domestic tillage and broadcasting equipment and their foreign counterparts. The research and development system remains imperfect, and there is a misalignment between promotion and application, thus hindering the formation of an internationally competitive industry chain for wear-resistant soil-engaging components. Finally, addressing the current challenges and deficiencies in the failure mechanisms, materials, structures, and processes of soil-engaging components in tillage and sowing machinery, this paper discusses the research and development directions aimed at enhancing wear resistance in agricultural machinery and equipment. 1) Enhance research on the wear resistance of soil-engaging components in diverse operational environments of tillage and sowing machinery; 2) Utilizing tribological theory, analyze the interaction laws of "environment, component, and material," thereby intensifying the development and research of substrate and coating materials for soil-engaging components; 3) Improve the optimization design of soil-engaging component structures to fulfill requirements for wear resistance, longevity, drag reduction, and lightweight properties; 4) To ensure the synchronized attainment of precision, strength, toughness, wear resistance, and prolonged service life in soil-engaging components, research on the process system of such components will be fortified, thereby furnishing theoretical foundations and technical support for research and engineering applications pertaining to enhancing surface wear resistance. [ABSTRACT FROM AUTHOR]