Advance of Study on Design Methods of Hydraulic System of Radio Remote Control of Construction Machinery

The working principle of radio remote controlling of construction machinery should be that signals of the radio wave from the transmitter obtained in the receiver were controlled and then changed into electronic analog or digital signals which can be used to drive different actuators and mechanisms of the vehicle.The vehicle could be acted by following the controlling instructions sent by the operator.The best operation mode of construction machinery is suitable not only to manual operating but also to remote controlling in the same vehicle.The design methods of the hydraulic system used for the radio remote controlling of construction machinery are discussed.The design methods of hydraulic circuits for the actuators controlled by solenoid on-off type valves,hydro-electronic multi-way proportional valves,closed loop proportional servo driver or three-way proportional reducing valves are discussed in detail (with real example).The design methods of the power shift transmission of electro-hydraulic controlling,the devices of braking and the directional streering are discussed in this paper.

Exploring the coupling relationship of industrial agglomeration and low-carbon economy considering spatiotemporal differentiation:An empirical study in China’s construction machinery industry

Although China’s construction machinery thrives to meet the needs of construction,a number of challenges still remain to be overcome,such as lack of thorough knowledge of regional disparities and several limitations in terms of carbon emissions and economic development.Meanwhile,a low-carbon economy was proposed and implemented in China.This research aims to investigate the differences in industrial agglomeration of construction machineries and further explore the relationship between industrial agglomeration and low-carbon economy.On this basis,spatiotemporal analysis was performed to evaluate the levels of industrial agglomeration in different regions based on the situations of China’s construction machinery industry.Furthermore,this study explored the interaction between industrial agglomeration and low-carbon economy utilizing the coupling coordination analysis method.Results showed that the coupling coordination of the two subsystems was extremely unbalanced in 2006,and it maintained an increasing trend,reaching a relatively high level in 2018.Finally,suggestions,such as establishing a policy guarantee system and implementing variable policies in different regions,were proposed to provide guidelines for the government decision-making and promote the sustainable development of China’s construction machinery industry.

Characterization of VOC emissions from construction machinery and river ships in the Pearl River Delta of China

Speciated characterization of Volatile Organic Compounds (VOCs),including oxygenated VOCs (OVOCs),from construction machinery and river ships in China is currently lacking.In this regard,we conducted field measurement on speciated VOC (including OVOC) emissions from six construction machinery and five river ships in the Pearl River Delta (PRD) region to identify VOC emission characteristics.We noticed that OVOC emissions from construction machinery and ships accounted for more than 50%of the total VOC emissions,followed by alkenes,aromatics and alkanes.Formaldehyde and acetaldehyde were the most emission species,accounting for 61.8%-83.2%of OVOCs.For construction machinery,the fuel-based emission factors of roller,grader and pile driver were 3.12,3.12 and 7.36 g/kg,respectively.With the rigorous restraint by the national emission standards,VOC emissions of construction machinery had decreased considerably,especially during stageⅢ.Ozone formation potential was also significantly reduced due to the significant decrease in emissions of OVOCs and alkenes with higher reactivity.For river ships,the fuel-based emission factors of cargo ships and speedboat were 1.46 and 0.44 g/kg,respectively.VOC emissions from construction machinery and river ships in Guangdong Province in 2017 were 8851.0 and 4361.0 ton,respectively.This study filled the knowledge gaps of reactive gas emissions from different kinds of non-road mobile sources over the PRD,and more importantly,highlighted the necessity in adding OVOC measurement to give a complete and accurate depiction of reactive gas emissions from non-road mobile sources.

Development of electric construction machinery in China:a review of key technologies and future directions

The issues of energy shortage and environmental pollution have accelerated the electrification of construction ma-chinery(CM)industry globally.In China,the amount of electric construction machinery(ECM)has been growing across the industry.The sales of ECM are estimated to reach 600000 vehicles by the end of 2025,while the total demand for battery power will reach 60 GWh.However,the development of ECM still faces critical challenges including reliable power supply and energy distribution among various components.In this review,we primarily focus on important technological breakthroughs and the difficulties faced by the CM industry in China.An overview of ECM including classification and characteristics is given at the beginning.Next,the selection of key components such as the electric motor and the energy storage units,and the control strategy in the pure electric drive system are discussed.The characteristics of the hybrid electric drive system such as structure design and power matching are analyzed in detail.The battery management system(BMS)is critical to ensure appropriate battery health for reliable power supply.Here,we extensively review technical developments in various BMSs.In addition,we roughly estimate the national total of CM emissions and the potential environmental benefits of employing ECMs in China.Finally,we set out future research directions and industrial development of ECM.

Effect of different machinery and rolling times on the microbial activity of reclamation soil in coal area

Mechanical construction will put influence on the biological characters of reclaimed soils,as well as the soil quality.In order to explore the changing rule of soil microbial quantity and respiratory capacity under different construction machineries and rolling times,and find the optimal processing conditions,an experiment was set up and a simulation experimental area was chosen,in which we simulated the main types of reclamation in coal mine area.After 2 years’natural aging,we collected surface soil samples(0-20 cm)that can be used for experimental analysis.The result shows that changing rules of soil biological factors are different with different construction machineries,and soil properties are closest to the normal soil when adopting the combination of“crawler dozer×5 compaction times”and“dump truck×3 compaction times”,which shows that the soil quality is better under this condition.

资源获得，国际化，和 Sany， XCMG，和 Zoomlion 的中国构造机械 ChampionsThe 大小写的追上来路径

This study investigates the internationalization and resource accumulation process of the three largest Chinese construction machinery companies： Sany, XCMG and Zoomlion. It takes a longitudinal approach to analyze the internationalization process of the three companies over the last 25 years. Although the three companies＇ paths in the early acquisition of technologies and firm-specific advantages （FSA） differ significantly, however, their internationalization process exhibits similar pattern. They all exploit the same home-country based FSAs in their south-south expansion into other emerging markets, and seem to mimic each other in their strategic moves. In the south-north expansion into advanced economies they skip the export stage and rely almost exclusively on foreign direct investment of both forms, greenfield and M＆A, to pursue asset augmenting objectives and overcome their ＂liability of origin＂. The study concludes by discussing several topics of interest, such as the implications of accelerated resource accumulation, the impact on competition with advanced multinationals in the home market or possible effects on the level of state support and risk taking behavior in the internationalization process by the companies＇ ownership type.