Search Results (11)

Electric forklifts are increasingly adopted in industrial environments due to their energy efficiency, reduced emissions, and lower operating noise compared to combustion alternatives. This paper presents a novel methodology for estimating the transported load weight in electric forklifts based on the output power signal of the DC–DC converter driving the electro-hydraulic lifting system. The proposed method leverages non-intrusive measurements of voltage and current to compute the lifting power, lifting speed, and energy, also allowing the computation of the lifting efficiency. The analysis confirmed that lifting energy is not linearly correlated with transported weight but lifting efficiency can be reasonably approximated as a function of lifting power and lifting speed, subsequently allowing the estimation of the transported mass. Experimental validation using 53 lifting events demonstrated that the methodology can estimate load weight with a reasonable mean absolute percentage error of 10.6% and 6.4% when using linear or multivariable regression analysis, respectively. These results demonstrate that the approach is sufficiently accurate for practical applications such as triggering load warnings when the estimated mass exceeds predefined safety thresholds. Full article

In tandem with the advancement of urban intelligent technology, the construction of remote monitoring platforms and databases for non-road mobile machinery is gradually improving in various provinces and cities. Employing the remote monitoring platform for non-road mobile machinery enables a detailed big data analysis of the actual operational state of the machinery. This method yields precise data on the activity levels of various machinery types. Importantly, it addresses the issue of reduced accuracy in emission inventories, which often arises from the conventional practice of using standard recommended values from the Guide to determine machinery activity levels during the compilation of non-road mobile machinery emission inventories. Based on the remote monitoring and management system of non-road mobile machinery, the actual value of the activity level of non-road mobile machinery was obtained, and the emission inventory of non-road mobile machinery in Shandong Province was established. The emission levels of PM, HC, NOx, and CO from main non-road mobile machinery, including forklifts, excavators, loaders, off-road trucks, and road rollers, were measured. The findings indicate that the operational activity levels of non-road mobile machinery in Shandong Province typically exceeded the guideline’s recommended values. Among them, the annual use time of port terminal ground handling equipment was the longest, with an average annual working time of 4321.5 h per equipment, more than six times the recommended value. Among all types of non-road mobile machinery, loader emissions accounted for the highest proportion, reaching 43.13% of the total emissions of various pollutants. With the tightening of the national standard for non-road mobile machinery from Stage II to Stage III, a significant reduction in actual mechanical emissions was observed, primarily manifested as a 91% decrease in NOx emissions. Based on the data from the remote monitoring platform, a new method for compiling the emission inventory of non-road mobile machinery is proposed in this paper. The calculated emission inventory can reflect more real emission situations and provide a reference and basis for emission control and sustainable emission reduction policy measures for non-road mobile machinery. Full article

In Korea’s air pollutant inventory, construction machinery is a major emission source in the non-road sector. Since 2004, the Korean government has introduced and reinforced emission regulations to reduce the air pollutants emitted from their diesel engines. Since the engine dynamometer test method used in emission regulations has limitations in reflecting emission characteristics under the diverse working conditions of construction machinery, it is necessary to examine the effectiveness of emission regulations and the validity of the emission factors applied as inputs to the air pollutants inventory. This could be done by evaluating engine operation and emission characteristics under real-world working conditions. In this study, 14 units were selected among the excavators, wheel loaders, and forklifts that represent approximately 90% of the registered construction machines in Korea. They were equipped with a portable emission measurement system (PEMS) to measure gaseous emissions and collect engine data under various real-world working conditions. With the reinforcement of emission regulations for the construction machinery from K-tier3 to K-tier4 in Korea, exhaust after-treatment technologies, such as selective catalytic reduction and diesel oxidation catalyst, were applied. Real world NOx was reduced by approximately 83%, and THC 77% and CO by 73%, respectively. Real world NOx + THC of the K-tier3 machines exceeded the laboratory emission limit, but the K-tier4 machines considerably improved, 20% for excavator (124 kW), 61% for excavator (90 kW), 90% for wheel loader (202 kW) and 21% for Fork-lift (55 kW), despite some differences. The emission factors applied to the air pollutant inventory have been developed using the engine dynamometer test method, but they were considerably underestimated compared with emissions under real-world working conditions. The difference was even larger for the K-tier4 machines. In this study, the possibility of developing emission factor equations that use the engine load factor as a parameter was confirmed by using the engine work 1 g/kW·h segment moving averaging window (MAW) method. Full article

With the acceleration of urban construction, the pollutant emission of non-road mobile machinery such as construction machinery is becoming more and more prominent. In this paper, a portable emissions measurement system (PEMS) tested the emissions of eight different types of construction machinery under actual operating conditions and was used for idling, walking, and working under the different emission reduction techniques. The results showed that the pollutant emission of construction machinery is affected by the pollutant contribution of working conditions. According to different emission reduction techniques, the diesel oxidation catalyst (DOC) can reduce carbon monoxide (CO) by 41.6–94.8% and hydrocarbon (HC) by 92.7–95.1%, catalytic diesel particulate filter (CDPF) can reduce particulate matter (PM) by 87.1–99.5%, and selective catalytic reduction (SCR) using urea as a reducing agent can reduce nitrogen oxides (NO_x) by 60.3% to 80.5%. Copper-based SCR is better than vanadium-based SCR in NO_x reduction. In addition, the study found that when the enhanced 3DOC + CDPF emission reduction technique is used on forklifts, DOC has a “low-temperature saturation effect”, which will reduce the emission reduction effect of CO and THC. The use of Burner + DOC + CDPF emission reduction techniques and fuel injection heating process will increase CO’s emission factors by 3.2–3.5 and 4.4–6.7 times compared with the actual operating conditions. Full article

Currently in Europe, road freight transport is characterized by the most dynamic advancement. Year after year, we may observe an increase in the amount of transported goods. The paper presents the emissions of gaseous exhaust components such as CO, THC, and NO_x as well as fuel consumption in freight transport. The emission analysis was performed for the entire transport cycle covering the handling of the goods with forklifts and carriage with a heavy-duty truck. The investigations were performed under actual conditions of operation using a Portable Emission Measurement System (PEMS). The fuel mileage was determined using the carbon balance method. The test routes were designed so as to reproduce the transport-logistic system typical of small towns. The setting for the tests was a town located in central Poland near the A2 motorway constituting part of the trans-European logistic network with multiple locations of logistic centers. In order to present the real emissions during handling, two test variants were considered: an outdoor variant (on a nearby lot) and inside a warehouse. The test run of the heavy-duty truck involved transporting 24,000 kg of load on urban and extra-urban (local and intercity) roads. The exhaust emissions and fuel mileage were determined for each of the stages as well as for the entire research cycle. Full article

The lithium-ion battery (LIB) represents a useful lever for reducing material handling equipment’s (MHE) environmental impact. The exploitation of opportunity charging might improve LIB adoption, which is still prevented by the high investment cost. Since opportunity charging is affected by the system organization, the relationship between LIB and organizational variables is a meaningful work direction to reduce warehouses’ environmental impact, which is underrepresented by the current literature. The present paper aims at filling this gap by investigating the implications of organisational variables on LIB adoption in warehouses where handling activities are performed with forklift trucks. Based on an in-depth review of the literature and semi-structured interviews, the research presents an input-process-output model linking organisational variables and LIB forklift related costs with an application to a real case. This paper is original as it extends findings from the research fields of production and mobility to the warehouse arena, and it opens room for further research on warehouse sustainability. The paper also offers insights to warehouse managers making decisions about LIB adoption for their electric forklift fleets. This is particularly meaningful to reduce warehouse environmental impact, since MHE power source significantly contributes to greenhouse gases emissions. Full article

Freight movement has always been, and always will be an essential activity. Freight transport is one of the most challenging sectors to transition to net-zero carbon. Traffic assignment, mode allocation, network planning, hub location, train scheduling and terminal design problem-solving have previously been used to address cost and operation efficiencies. In this study, the interdisciplinary transition innovation, management and engineering (InTIME) methodology was used for the conceptualization, redesign and redevelopment of the existing freight systems to achieve a downshift in fossil energy consumption. The fourth step of the InTIME methodology is the conceptualization of a long-term future intermodal transport system that can serve the current freight task. The novelty of our approach stands in considering the full range of freight supply chain factors as a whole, using an optimization-simulation approach as if we were designing the low-carbon system of 2121. For the optimization, ArcGIS software was used to set up a multimodal network model. Route and mode selection were delivered through the optimization of energy use within the network. Complementarily, Anylogic software was used to build a GIS-based discrete event simulation model and set up different experiments to enhance the solution offered by the network analysis. The results outline the resources needed (i.e., number of railway tracks, train speed, size of railyards, number of cranes and forklifts at terminals) to serve the freight task. The results can be backcast to reveal the most efficient investments in the near term. In the case of New Zealand’s North Island, the implementation of strategic terminals, with corresponding handling resources and railyards, could deliver 47% emissions reduction from the sector by 2030, ahead of longer lead-time upgrades like electrification of the railway infrastructure. Full article

Heavy forklifts that are widely used in ports and stations have large gravitational potential energy at the lowering of the boom. As concerning the large rated power level, the engine is still the main power source for the heavy forklifts. With the increasingly stringent emissions regulations, the electric heavy forklift becomes an important choice. The structure and the working mode of an electric heavy forklift are introduced. Additionally the schematic of double hydraulic motor-generators is adopted to regenerate the potential energy when the boom is descending. The judge rule of the working mode and control strategy are analyzed. A test rig of a prototype electric heavy forklift is established. Control mode discrimination of potential energy regeneration, the control performance and the influence factors on regeneration efficiency are tested based on the test rig. The experimental results show that the discrimination method of the working mode of the proposed double hydraulic motor-generators with a potential energy regeneration system for potential energy is feasible. The descending of the lifting cylinder is consistent with the handle. The forklift can obtain the good following ability. Although the lifting cylinder descends at low velocity, the velocity is stable and the fluctuation of the rodless chamber pressure is within 0.1 MPa. With the increase of the load mass and descending velocity, the regeneration efficiency increases accordingly. The maximum efficiency is up to 74%. Hence, the proposed potential energy regeneration system is feasible and potential energy regeneration system does not affect the control performance of the boom. Full article

In recent years, the continuous increase of greenhouse gas emissions has led many companies to investigate the activities that have the greatest impact on the environment. Recent studies estimate that around 10% of worldwide CO₂ emissions derive from logistical supply chains. The considerable amount of energy required for heating, cooling, and lighting as well as material handling equipment (MHE) in warehouses represents about 20% of the overall logistical costs. The reduction of warehouses’ energy consumption would thus lead to a significant benefit from an environmental point of view. In this context, sustainable strategies allowing the minimization of the cost of energy consumption due to MHE represent a new challenge in warehouse management. Consistent with this purpose, a two-step optimization model based on integer programming is developed in this paper to automatically identify an optimal schedule of the material handling activities of electric mobile MHEs (MMHEs) (i.e., forklifts) in labor-intensive warehouses from profit and sustainability perspectives. The resulting scheduling aims at minimizing the total cost, which is the sum of the penalty cost related to the makespan of the material handling activities and the total electricity cost of charging batteries. The approach ensures that jobs are executed in accordance with priority queuing and that the completion time of battery recharging is minimized. Realistic numerical experiments are conducted to evaluate the effects of integrating the scheduling of electric loads into the scheduling of material handling operations. The obtained results show the effectiveness of the model in identifying the optimal battery-charging schedule for a fleet of electric MMHEs from economic and environmental perspectives simultaneously. Full article

Increasing the fuel efficiency of industrial machines through digitalization can enable the transport and logistics sector to overcome challenges such as low productivity growth and increasing CO₂ emissions. Modern digitalized machines with embedded sensors that collect and transmit operational data have opened up new avenues for the identification of more efficient machine use. While existing studies of industrial machines have mostly focused on one or a few conditioning factors at a time, this study took a complementary approach, using a large set of known factors that simultaneously conditioned both the fuel consumption and productivity of medium-range forklifts (n = 285) that operated in a natural industrial setting for one full year. The results confirm the importance of a set of factors, including aspects related to the vehicles’ travels, drivers, operations, workload spectra, and contextual factors, such as industry and country. As a novel contribution, this study shows that the key conditioning factors interact with each other in a non-linear and non-additive manner. This means that addressing one factor at a time might not provide optimal fuel consumption, and instead all factors need to be addressed simultaneously as a system. Full article

Forklift for industrial field is mostly used in closed area like warehouses or factories. Therefore, the emission issue of forklift is more serious than that of usual vehicles outdoors. And forklift is required the compact size and high power driven system for the efficient work in a limited area. In EVS20 at Long Beach, we presented a paper about the power capacitors for battery forklift for the first time. This time, we will present our latest development for new model Battery Forklift which is far superior to the conventional type. AC motor driven system newly developed by TOYOTA INDUSTRIES CORP. provides higher performance and smaller size than the conventional system by installing higher quality and smaller AC controller and AC motor driver. NIPPON CHEMI-CON CORP. developed Power Capacitors in the inverter circuit. The total volume of new capacitors reached nearly half (↑47%) compared with the conventional type by reducing the internal resistance and adopting optimized cooling structure. In this paper, we will describe the upgrade of TOYOTA 48V Battery Forklift, AC motor driven system and the development of Power Capacitors for the inverter use. Full article