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This study aims to improve the contradiction between the power and economy of tractor in field operation. A comprehensive mode switching mode was developed for the tractor with the hydro-mechanical continuously variable transmission (HMCVT). The engine torque and fuel consumption model, the HMCVT model, and the tractor dynamic model were built to consider the slip rate of the driving wheel. The economic and dynamic mode switching was introduced the weight coefficient for the power and economy under different working conditions. At the same time, the economic and dynamic speed of mode switching was taken as the constraint of comprehensive mode switching speed. The weight coefficient was solved by the fuzzy reasoning, according to the throttle opening and speed. The multi-objective evolutionary and decomposition were used to optimize the weight coefficient to deal with the comprehensive mode switching speed under different throttle opening. Then, the comprehensive mode switching was worked out. The dynamic and economic performance, as well as the comprehensive mode switching were applied to the mode switching strategy module for the simulation and comparative analysis. The simulation results show that the mode switching speed and the fuel consumption rate of comprehensive mode switching were between the power and economic mode switching under the throttle opening of 0.5, compared with the economic mode switching. The speed of mode switching was reduced under the comprehensive mode switching, indicating the less power loss, and the improved power performance, compared with the dynamic mode switching. There was the lower fuel consumption rate corresponding to the mode switching speed of the comprehensive mode switching, indicating the improved economy. The comprehensive mode switching presented both the power and economic mode switching. The mode switching speed was adjusted in the real time, according to the actual operating conditions of the tractor, indicating a reasonable distribution of power and economy. Meanwhile, the mode switching test was conducted on the experimental bench to verify the accuracy of the comprehensive mode switching, where the throttle opening was set as 0.5. Correspondingly, the simulation data was basically consistent with the experimental data. Therefore, the tractor can be expected to switch the mode, according to the set comprehensive mode switching at high speed and large throttle opening, which verified the effectiveness of the comprehensive mode switching. Therefore, the comprehensive variable speed can fully meet the demand of power performance and economy of tractor under different working conditions. The findings can also provide a theoretical reference to formulate the mode switching in tractors. [ABSTRACT FROM AUTHOR]

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This article studies the influence of dual-credit policy on the production decision and profit of heterogeneous automobile manufacturers at the enterprise level, as well as on the total output and total output value of new energy vehicles and fuel vehicles at the industry level, by modeling the production game equilibrium of heterogeneous automobile manufacturers under the dual-credit policy. The main conclusions are as follows: ① In the process of the evolution of the new energy vehicle industry, the new energy vehicle manufacturers still have certain development potential, but the backbone of the future development depends on the dominant fuel vehicle manufacturers. Dominated fuel vehicle manufacturers may become dominant fuel vehicle manufacturers by improving fuel economy, thus increasing the total production of dominant fuel vehicle manufacturers and reducing the total production of dominated fuel vehicle manufacturers. ② Dual-credit policy parameters have different effects on the production decisions and profits of heterogeneous manufacturers. The new energy vehicle manufacturers can benefit from it, while the dominated fuel vehicle manufacturers are faced with a crisis. The possible ways to turn the crisis around include reducing the average fuel consumption and actively exploring the possibilities of new energy vehicle production. For the dominant fuel vehicle manufacturers, the tightening of the dual-credit policy may lead them to switch to the fuel vehicle market. Regulating the upper limit of NEV credit price is beneficial to guide them to turn to the new energy vehicle market. ③ The parameters that promote the scale growth of new energy vehicles may lead to a decline in total output value. Policy adjustments should take the scale growth and output value growth as dual goals to avoid market fluctuations that may result from a single target. ④ With the tightening of the dual-credit policy, the foreseeable increase in the proportion of new energy vehicle credit requirement and the tightening of the corporate average fuel consumption standard will stimulate the increase in the demand for new energy vehicle credits and alleviate the imbalance between the supply and demand of new energy vehicle credits. Considering the relatively low price of NEV credits at present, a reasonable reduction of new energy passenger vehicle credits is helpful to reduce the NEV credit supply. [ABSTRACT FROM AUTHOR]

In view of the pattern of multiple gas supply in cities, a series of problems about gas interchangeability are brought to our attention. For atmospheric gas burner, integrated gas interchangeability and blending test system has been designed for laboratory research, which includes dynamic gas-mixing system and combustion characteristics of gas appliances testing system. The devices have the advantages of small and accurate multi-gas blending, fast respond speed, instant blending and use, digital display instrument, and continuous gas flowing. Besides, the system has huge advantages in determining the flexible range of gas appliances to different gases. Many problems have been solved perfectly by using this system, such as large space occupation, the unevenness of gas mixture, long time lag, and wasting gas. [ABSTRACT FROM AUTHOR]

Based on the quality characteristic of current coal-based substitute natural gas (SNG), the composition, high calorific value, interchangeability and water dew point for coal-based SNG are presented. The comparison between coal-based SNG and conventional natural gas s completed comprehensively, and essential property and fuel gas quality of coal-based SNG are pointed out. It is illustrated that there is no constrained problem for coal-based SNG incorporation and interchange application with traditional natural gas, and the coal-based coal-based SNG s clean fuel gas in high quality as a beneficial and necessary supplementary for conventional natural gas. This paper provides references for coal-based SNG promotion and application as a new kind of clean energy resource, and coal-based SNG quality standard establishment. [ABSTRACT FROM AUTHOR]

Industrial gas appliances have a huge market prospect in boilers and industrial furnaces. In this paper, gas burners and its working process was briefly introduced. Based on EN676, a new test method of natural gas interchangeability was put forward to test industrial appliances' combustion performance. Three typical burners were selected to test the thermal performance when fuelled with 6 kinds of natural gases. The results showed that this method is suitable for interchangeability study of boiler burner, and its reliability was proven. [ABSTRACT FROM AUTHOR]

The AGA Indices method and weaver indices method are typical overseas interchangeability discriminant methods. Under the background of interchangeability of multi-source natural gas in Shanghai, the pipeline gas in lab is used as reference gas, the AGA Indices (IL, IF, IY) and Weaver Indices (JH, JA, JF, JL, JI, JY) of all kinds of substitute gas were calculated. The interchangeability of reference gas and substitute gas was analyzed theoretically and experimentally. Finally, compared tests with the calculation results, analyzed and discussed the domestic applicability of two indices methods. The tests proved AGA Indices method could well predicted interchangeability but did not give the emission index of CO, while Weaver Indices could well predict flame-out, backfire and heat load change but did not accurately reflect yellow flame and CO emission. Therefore, in order to reflect completely the results of interchangeability by pure index methods, it is necessary to analyze the interchangeability combining domestic reality with two indices methods. Nowadays experiment is still an essential way for identifying interchangeability. And gas interchangeability should not be confused with gas classification. [ABSTRACT FROM AUTHOR]