Heavy-duty Machinery Research Articles

Influence of carbon percentage on the wear and friction characteristics of ATOMET 4601 alloys in heavy-duty machinery

Heavy-duty machinery demands materials with strong wear resistance and good frictional properties, which conventional materials often lack. The knowledge of PM alloys’ friction and wear characteristics versus standard steel materials is limited. ATOMET 4601, a high-strength prealloyed powder with excellent compressibility, allows for parts with densities over 6.8 g/cm³. Carbon (0, 0.5, 1.0 wt.%) was added to enhance performance. These alloys, compacted to 75% of theoretical density and sintered at 1100 ± 10°C, were tested for wear and friction against EN31 steel. Results showed carbon improved tribological performance, with ATOMET 4601 + 1.0%C exhibiting the best wear resistance. Regression models and interaction plots indicated significant effects of load and speed on wear rate and coefficient of friction. Microstructural analysis revealed carbides and oxides in the ferrite matrix, with adhesive, abrasive, and oxidative wear as primary mechanisms.

Identifying and modelling the barriers to returns of end-of-life (EOL) heavy-duty machinery in Nigeria: A consumers’ perspective

EOL product returns has become more prevalently practiced in companies in developed nations as a response to government's strict regulations and customers' expectations. Correspondingly, there is a growing body of theoretical literature on the topic within this context as a crucial strategy to accelerate the development of the circular economy (CE). However, consumers' participation in EOL returns of heavy-duty machinery is immature in developing nations due to barriers, and studies are scarce on the analysis of the barriers. To fill this gap, this study aims to identify and analyze the barriers that hinder consumers' participation in EOL returns of heavy-duty machinery within a developing nation-Nigeria. Barriers were identified from published literature and experts' inputs and then, classified under technological, organizational, and environmental (supply chain) categories. Then, analysis was done via a methodology integrating interval-valued neutrosophic analytical hierarchy process (IVN-AHP) with multi-objective optimization on the basis of a ratio analysis plus the full multiplicative form (MULTIMOORA). Findings indicate that the environmental(supply chain) barriers rank the highest, followed by technological barriers. Specifically, consumers participation in EOL returns of heavy-duty machinery in Nigeria is mostly hindered by lack of regulations, lack of financial incentives, lack of skills, undeveloped reverse logistics system and poor access to facilities for recovery operations. Furthermore, we proposed some strategies to support stakeholders to mitigate the barriers. Thus, this study gives valuable guidelines to decision-makers to enable the transition to a CE paradigm in the heavy-duty sector within developing nations for utmost sustainability.

Finite element analysis & topology optimization of excavator bucket teeth for optimal performance

In the realm of heavy-duty machinery, excavators hold pivotal roles in construction, mining, and various large-scale projects. The excavator's efficacy relies significantly on its bucket teeth, crafted from robust materials like steel, crucial for soil and rock excavation. However, inadequacies in tooth shape and composition can lead to wear which in turn leads to diminished productivity. Employing finite element analysis, the present research delves into the influence of cantilever profile on TATA Hitachi Ex70 and JCB JS81 bucket teeth, using AISI 4340 and AISI 4140 materials, respectively. Analysing von Mises stress and deformation through Altair HyperMesh, subsequent Altair OptiStruct facilitates topology optimisation aims to reduce tooth mass. It appears that Tooth I (TATA Hitachi Ex70) experienced a decrease in mass, yet an elevation in von Mises stress compared to its initial mass of 2.81 kg and stress level of 1.74 E + 02 MPa. Similarly, Tooth II (JCB JS81) showcased a reduction in mass and a rise in von Mises stress from its original mass of 2.03 kg and stress of 1.038 E + 02 MPa. Validation of optimised designs through the graphs depicting the Factor of Safety (FOS) for both teeth ensures compliance with specified requirements, confirming that optimised excavator bucket teeth designs are safe.

Structure optimization design approach of friction pairs for low-temperature rise wet brake in hydraulic motor

Cam-lobe radial-piston hydraulic motors are widely used in large heavy-duty machinery as direct-drive components of hydraulic systems. Due to their extremely high output torque and power density, the wet brake equipped with the hydraulic motors are necessary to achieve ultra-high braking torque in a compact space. However, due to a large number of internal friction pairs and small fit clearance between multiple friction pairs in wet brake, the rotation of the friction pairs in non-braking state will cause large friction torque loss and obvious temperature rise, thereby leading to the thermal failure of wet brake. How to optimize the structure of friction pairs to reduce the temperature rise of wet brake in non-braking state is a persistent challenge. Existing structure optimization design approaches of friction pairs in brakes mainly focus on the structure of each friction pair, which ignore the effect of fit clearance between the friction pairs on the temperature rise of brakes. Nevertheless, the fit clearance between friction pairs is an important factor that affect the temperature rise. For that, this study proposes a two-step structure optimization design approach of friction pairs for low-temperature rise wet brake in hydraculic motor, which simultaneously considers the fit clearance between the friction pairs and the structure of each friction pair. In this approach, the design process could be divided into two steps: firstly, the influence of fit clearance between multiple friction pairs on the temperature rise of wet brake in non-braking state is analyzed and optimized by the temperature rise theoretical model; secondly, in order to further reduce the temperature rise of wet brake, the oil groove structure of each friction plate are introduced and optimized by fluid-solid-thermal coupling simulation method. By this approach, the low-temperature rise structure of friction pairs with the optimized fit clearance between multiple friction pairs and oil grooves of each friction plate. Finally, a series of experiments are conducted to verify the effectiveness of the design approach. The result show that the temperature rise of wet brake could be effectively reduced 12 % by optimizing the structure of wet brake, demonstrating that the structure optimization design approach could provide a theoretical guidance to design low-temperature rise wet brake for large torque hydraulic motors.

Assessment of Mine Plans for Production and Variations at Ibese Limestone Mines

This research investigated the mine plans used for the production target and annual production of limestone for the past seven (7) years. The actual amount of limestone produced per year in tons was computed to determine the variations in the mine's production and the life span of the reserve of limestone deposits. A new mine plan was proposed, and a targeted amount of limestone production per year was suggested. The mine plans for the mine's production were generated from 2014 to 2020 using a complete data collection system for Real Time (RTK) GPS and Total Stations with in-field coordinate geometry called SurCE by Carlson Software. The total production target for the seven (7) years was 87,017,146 tons and the actual production was 76,313,056 tons. The total variations for the years under this assessment were -10,704,090 tons except for the year 2018 when the actual production was higher than the production target of 511,179 tons. The volumetric reserve estimation revealed that the total volume of the limestone reserve is 5,052,236,090.186 tons. The expected production per week was computed to be 356,400 tons/week, expected monthly production, (EMP) was estimated to be 1,425,600 tons/month. The expected production year, (EPY) was 17,107,200 tons/year and the life span of the limestone deposit, (LS) was computed to be 295.34 years. It can be suggested that the company should target a production rate of 1,425,200 monthly and 17,104,200 per year. This suggestion can be achieved if there is enough investment in terms of skilled labour, heavy-duty machinery, and equipment which will cost-effectively boost production.

Occupational Safety Risk Assessment for Wola Heavy-Duty Machinery Operator in a Romanian Diabase Open –Pit Mine

Abstract Occupational safety risk assessment is always the basic stage of the systematic approach of reducing the impact of undesired events (work injuries and occupational illnesses), by decreasing both their likelihood of occurrence and the gravity/severity of the generated impact. Eighteen years ago, when, as a consequence of the regulatory changes induced by our country’s accession into the European Union, the risk assessment became mandatory/compulsory. Since then some progress was factually realized in the spirit of applying different risk analysis techniques in all Romanian organizations. Even if there are many aspects that are requiring further improvement, an effectively validated and nationally accepted indigenous tool is nowadays available. This method was put in practice in this research paper, in order to analyse, evaluate and assess the safety risks related to several of the main activities/jobs in a diabase open pit mine exploiting construction stone in a certain province of the country. Based on the results obtained, it has become feasible to propose realistic measures aimed at preventing the identified and quantified risks located in the field of unacceptable risks and protecting exposed workers to their effects. The case study developed and synthesized in this article confirms the capability of the risk assessment process to facilitate the substantiation of the decisions regarding the allocation of resources towards the minimization of the risks encountered in the work processes by different categories of workers in the mining companies.

An Energy-Efficient Adaptive Speed-Regulating Method for Pump-Controlled Motor Hydrostatic Drive Powertrains

In this paper, a closed hydrostatic drive powertrain (HSDP) composed of an engine, a variable pump, a variable motor, and an energy-efficient adaptive speed-regulating controller (ADC) based on power following is proposed and investigated. The controller can more than guarantee accurate regulation of motor speed through online efficiency estimation based on established loss models of the pump and the motor. It also facilitates the optimal efficiency control of the engine and hydrostatic system through two redundant control freedoms of the HSDP system, making an energy-saving adjustment of the motor speed. At the same time, the controller can prevent engine overload stall and high system pressure by limiting the displacement of the pumps and motors in real time based on the system loads to improve the automatic adaptability of the system to varying loads. Field testing experiments performed by means of a heavy transportation vehicle under different conditions were conducted to verify the efficacy of the proposed controller. The results showed that the average errors of motor speed were 3.3% under empty load conditions and 9.6% under heavy load conditions. In terms of energy saving, comparison tests involving a rule-based controller (RBC) and the ADC were carried out, and the results showed that the energy-saving ratio of the ADC was at least 11.5% and up to 25.8% under empty load conditions and at least 2.8% and up to 9% under heavy load conditions. The ADC controller showed good performance in terms of speed control, load adaptability, and energy saving and a superior advantage due to its simple structure and ease of implementation. Therefore, the proposed controller is an excellent choice for the real-time control of machinery with an HSDP system, especially heavy-duty machinery.

ZnFe2O4@C/graphene oxide nanocomposites designed for enhancing the friction reduction property of lubricants

Improving the friction reduction property of lubricant to ensure the efficient operation of advanced heavy-duty machinery has been taken seriously. Herein, as a novel additive with a distinctive sphere-on-sheet structure, ZnFe2O4@C/graphene oxide (ZnFe2O4@C/GO) nanocomposites were designed via the response surface method to drastically enhance the friction reduction property of the polyalphaolefin oil. The particular lubrication mechanism of the ZnFe2O4@C/GO nanocomposites was simultaneously revealed. Results showed that the friction coefficient could be reduced by an order of magnitude (less than 0.05) at several frictional moments under the contact stress of 1.20 GPa when the ZnFe2O4@C/GO nanocomposites were added to polyalphaolefin oil. Specifically, the largest decrease in friction coefficient during the friction process was from 0.24 to 0.025 (approximately 90 %). According to the molecular dynamics simulations, the outstanding friction reduction property of the ZnFe2O4@C/GO nanocomposites was determined by the sliding structures with low shear force between the bent graphite in the ZnFe2O4@C microspheres and the graphene tribofilms at the friction interface. These findings reveal the application prospects of the ZnFe2O4@C/GO nanocomposites as a superior lubricant additive for advanced heavy-duty machinery in the future.

Hyperconnected Logistic Platform for Heavy-Duty Machinery: Leveraging Physical Internet Principles to Drive the Composting Industry

The Physical Internet (PI) envisions a global logistics system that integrates physical, digital and operational connections. This study aims to develop a hyperconnected logistic platform for heavy-duty machinery (HDM) in the composting industry by utilizing a systematic methodology. The proposed architecture consists of four layers: the Domain Model, the MBSE Model, the Information Sharing Model and the Agent-based Simulation Platform. The Domain Model analyzes the current situation and investigates stakeholder viewpoints, and the MBSE Model reduces complexity and describes mutual interactions between requirements and needs. The Information Sharing Model focuses on the information exchange among the main components, and the Agent-based Simulation Platform implements the proposed platform. The feasibility of the proposed architecture is demonstrated through a use case in Styria, Austria. Three simulation-based scenarios are analyzed, starting from the semi-hyperconnected approach up to the hyperconnected approach with PI vision integration. The results indicate that the hyperconnected platform is successful in serving all composting facilities, leveraging underutilized resources and promoting high-quality compost production. Thus, the platform provides support in a local, communal setting, resulting in enhancing the circular economy within the composting sector. Our efforts aim to contribute to the realization of the Physical Internet vision and promote composting to ultimately achieve a more sustainable future.

Case study of vibration in a mobile milling machine

Many industries rely on heavy-duty machinery such as cranes, pipelines, motors, which are subject to wear and tear. Milling of such parts using conventional machine tools presents many drawbacks and is impossible in some cases. In such situations, mobile machine tools can be used to machine directly on site. However, mobile machines are flexible, and are prone to detrimental vibrations during cutting operations. Vibrational stability in the surfacing process has been extensively studied in conventional milling. However, the focus of this article is an original study on a mobile milling machine used for on-site surfacing operations. An experimental investigation into the vibrational behavior of the machine is carried out and a sensorless method is used to detect the onset of chatter. Machine flexibility is discussed using a tool-point frequency response function and references from the literature. Milling operations are carried out over a range machining parameter to determine an experimental stability limit. Internal sensors for spindle motor consumption and spindle motor encoder are monitored during the machining process. A threshold is established for determining the appearance of chatter using only the machine’s internal sensors.

A monosurfactant-stabilized dual-responsive and versatile emulsion lubricant

Emulsions consisting of lubricating base oil and water have extensive applications in the fields of metalworking and heavy-duty machinery. Due to the compositional complexity that confines an effective recycling of emulsion constituents and the frequent use of toxic, non-biodegradable mineral base oil, an industrial emulsion lubricant is usually easy to produce severe environmental burdens and health issues. Here we report a dual-responsive and versatile lubricating emulsion solely consisting of water, an eco-friendly ester base oil and a synthetic cationic emulsifier. Taking advantage of the inclusion of azobenzene moiety, [CeCl3Br]- anion and methylimidazole head-group, the surfactant can not only undergo tribochemical reactions to function as a lubricant additive to achieve very low interfacial friction, but also endow the resulting emulsion efficient anticorrosion, antibiosis and both light- and magneto-responsiveness. Based on a reversibly photo-triggered variation in the hydrophobicity of surfactant, an on-demand separation and recycling of emulsion component followed by a nearly one order of magnitude conversion in the friction can be realized. Together with its magneto-controlled migration and adaptivity to high normal loads, we envision that the emulsion lubricant may find potential applications in a broad range of industrial systems requiring lubrication and heat dissipation as well as smart devices needing control over the friction between two contacting surfaces.

An IIoT-Based Approach to the Integrated Management of Machinery in the Construction Industry

In recent years, considerable advances in connecting industrial equipment to the Internet allowed a higher level of operational efficiency, productivity, and automation. Nevertheless, the construction industry still presents challenging requirements, like long-distance wireless communication, interconnection of out-of- coverage areas, constant mobility of machinery, and support for legacy and proprietary systems. All these requirements pose different challenges when compared with traditional smart factory Industry 4.0 solutions. This paper discusses some of the current key questions regarding fleet management in the construction industry, identifies requirements for heavy-duty machinery, and proposes an Industrial Internet of Things (IIoT)-based solution for the integrated monitoring of such machinery. Also, it proposes and presents an open, innovative solution for the integrated management of non-standardized civil construction vehicle technologies. The developed prototype uses the J1939 protous and protocol to collect machinery status and Long-Range Wide Area Network (LoRaWAN) to communicate the monitored data. The solution was assessed at the construction site of the new port of Sines in Portugal. A detailed description of the proposed system is provided, along with information on trials and evaluation results regarding its performance. Additionally, the paper provides insights into open issues and challenges in this field and how our solution can contribute to overcoming them.

A study on the chemical profile and the derived health effects of heavy-duty machinery aerosol with a focus on the impact of alternative fuels

The combustion of petroleum-based fossil fuels is associated with a high environmental burden. Several alternative fuels, including synthetic fuels (e.g., gas-to-liquid, GTL) and biofuels (e.g., rapeseed methyl ester, RME) have been studied in the last few years. While the advantages for the environment (sustainability of biofuels) are well known, research on the resulting health effects from combustion aerosols of these alternative fuels is still scarce. Consequently, we investigated the chemical combustion profile from three distinct fuel types, including a petroleum-based fossil fuel (B0) and two alternative fuels (GTL, RME) under real exposure conditions. We sampled particulate matter (PM2.5, PM0.25) and the gas phase from heavy-duty machinery and evaluated the general pattern of volatile and semi-volatile organic compounds, elemental and organic carbon as well as a range of transition metals in the size segregated PM and/or gas phase. The use of comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry enabled us to classify distinct methylated PAHs in the PM samples and its high abundance, especially in the fine fraction of PM. We found that (methylated) PAHs were highly abundant in the PM of B0 compared to GTL and RME. Highest concentrations of targeted aromatic species in the gas phase were released from B0. In summary, we demonstrated that GTL and RME combustion released lower amounts of chemical compounds related to adverse health effects, thus, the substitution of petroleum-based fuels could improve air quality for human and the environment.

Can the long-term effects of beach cleaning heavy duty machinery on aeolian sedimentary dynamics be detected by monitoring of vehicle tracks? An applied and methodological approach

Beach-dune systems are fragile ecosystems vulnerable to changes, especially those associated to human activities. This study focuses on El Inglés beach (Canary Islands, Spain), which is located on the eastern limit of the Maspalomas dunefield. This is the sediment input to the dunefield, and vehicles that provide urban-touristic services circulate every day, most notably heavy duty machinery responsible for beach cleaning. The aim of this study is to make a first methodological approach and a quantitative and empirical analysis of the long-term environmental effects, especially on the topography and geomorphology, that mechanical beach cleaning services could have on the aeolian dynamics, using as an indicator the vehicles tracks mapping.The methodology is divided into four sections: i) a spatiotemporal study of vehicle tracks on the beach; ii) a field campaign to observe beach cleaning activities in situ and compile data; iii) an interview with the local team responsible for beach cleaning; and iv) a general analysis of the aeolian dynamics over the almost last two decades.Results shown not only a high correlation between vehicle tracks and heavy duty machinery tracks, but also the variation in vehicle track density was proven to follow changes in the management process and the number of tourists. Different track densities varied depending on the intensity of the presence of visitors and hence the intensity of beach use, which is not homogeneous throughout the beach. A study of the deflation surfaces as erosion process found that they not only remain steady but even increase in some areas with high vehicle track densities, with no sedimentary gain. Although management activities like cleaning and levelling may not have a direct impact on the dunefield, they were positively correlated to deflation surfaces, increasing sediment loss in the beach area. These activities could be leading an artificially-maintained steady beach contrary to documented sedimentary loss in the dunefield. In conclusion, the pioneer approach of analysing the vehicle traffic through tracks monitoring, especially beach cleaning activities, has shown the viability to detect long-term effects on the sedimentary dynamics, including sediment loss to the foredune and, therefore, inside the system.

Maintenance management of large-size rolling bearings in heavy-duty machinery

Slewing bearings are one of the most important elements in the vast majority of large-size machines. They are widely used in the mining industry: tunnel cutters, bucket excavators and many other devices. In a Bucket-wheel excavator, continuous rotation of the body is most advantageous due to the technique of digging the input or coal. The rotational movement of the machine is then the basic cutting movement, and the delivery movement, carried out by driving the machine, is only an auxiliary movement. A similar kinematics occurs in tunnel cutters. Therefore, these bearings have played such a significant role and have been the subject of extensive research and continuous improvement over the years. High demands are placed on them in terms of load capacity, friction, accuracy, durability and reliability. It happens, however, that despite careful design and manufacture, the bearings do not achieve the required durability. Failures usually result in economic losses due to loss of production, damage to adjacent parts and repair costs. Premature bearing failure can occur for a variety of reasons. Each failure leaves its own special mark on the bearing. Consequently, by examining the damaged bearing, it is in most cases possible to find the root cause and define corrective actions, thus preventing further failures. This publication aims to provide basic knowledge about the factors determining the load capacity and durability of large-size slewing ring bearings and the analysis of their damage. The result of the considerations is finding the sources of errors in determining the load-bearing capacity characteristics of roller slewing bearings. For this purpose, the ISHIKAWA and FMEA methods were used and the risk level for errors was determined. Moreover, the article presents some forms of damage to raceways of slewing bearings and indicates their causes. Changes in the so-called angle of action of the rolling elements in the ball bearing due to the transferred loads. The influence of changes in this angle on the geometry of the contact zone of the rolling elements and raceways was investigated. It has been shown that the contact angles of some rolling elements increase significantly. This can damage the raceway by chipping or rolling the edge of the bearing ring. With the knowledge presented in this article, it is possible to evaluate various emergency situations and start their proper analysis.

Rocky-CenterNet: Detecting rocks using convolutional neural networks and ellipses

<h2>Abstract</h2> Rocky-CenterNet is an algorithm based on convolutional networks, aimed at detecting rocks and other ellipse-shaped objects. Instead of representing rocks as bounding boxes or segmentation masks, Rocky-CenterNet models rocks as ellipses. Rocky-CenterNet provides a rich description of the shape of the rocks, while running as fast as object detectors based on bounding boxes. The original implementation of Rocky-CenterNet is made available online. It is built on the original implementation of CenterNet, which is itself implemented in Pytorch. Rocky-CenterNet is useful for automation of heavy-duty machinery in mining related tasks, like autonomous loading of material with LHDs and autonomous rock-breaking hammers.

Detecting rocks in challenging mining environments using convolutional neural networks and ellipses as an alternative to bounding boxes

The automation of heavy-duty machinery and vehicles used in underground mines is a growing tendency which requires addressing several challenges, such as the robust detection of rocks in the production areas of mines. For instance, human assistance must be requested when using autonomous LHD (Load-Haul-Dump) loaders in case rocks are too big to be loaded into the bucket. Also, in the case of autonomous rock breaking hammers, oversized rocks need to be identified and located, to then be broken in smaller sections. In this work, a novel approach called Rocky-CenterNet is proposed for detecting rocks. Unlike other object detectors, Rocky-CenterNet uses ellipses to enclose a rock’s bounds, enabling a better description of the shape of the rocks than the classical approach based on bounding boxes. The performance of Rocky-CenterNet is compared with the one of CenterNet and Mask R-CNN, which use bounding boxes and segmentation masks, respectively. The comparisons were performed on two datasets: the Hammer-Rocks dataset (introduced in this work) and the Scaled Front View dataset. The Hammer-Rocks dataset was captured in an underground ore pass, while a rock-breaking hammer was operating. This dataset includes challenging conditions such as the presence of dust in the air and occluded rocks. The metrics considered are related to the quality of the detections and the processing times involved. From the results, it is shown that ellipses provide a better approximation of the rocks shapes’ than bounding boxes. Moreover, when rocks are annotated using ellipses, Rocky-CenterNet offers the best performance while requiring shorter processing times than Mask-RCNN (4x faster). Thus, using ellipses to describe rocks is a reliable alternative. Both the datasets and the code are available for research purposes.

Robustness Analysis of an Electrohydraulic Steering Control System Based on the Estimated Uncertainty Model

The impossibility of replacing hydraulic drives with other type drives in heavy duty machinery is the main reason for the development of a system for controlling hydraulic power steering. Moreover, the need for remote automatic control of the steering in specific types of mobile machinery leads to significant scientific interest in the design of embedded systems for controlling electro-hydraulic steering units. This article introduces an approach, which has been developed by authors, for robust stability and robust performance analysis of two embedded systems for controlling electro-hydraulic power steering in mobile machinery. It is based on the suggested new more realistic “black box” SIMO model with output multiplicative uncertainty. The uncertainty is obtained by parameters confidence interval and Gauss approximation formula. The embedded control systems used a linear-quadratic Gaussian (LQG) controller and H∞ controller. The synthesis of the controllers was performed on the basis of a nominal part of an uncertainty model. Robust stability and robust performance analyses were performed in the framework of a so-called structured singular value, μ. The obtained theoretical results were experimentally approved by real experiments with both of the developed control systems, which were physically realized as a laboratory test rig.

Study of heat generation and dissipation mechanism for an exciter shaft and its impact

Compactor is a heavy-duty machinery that uses compaction to reduce the size of waste materials or biomass or compaction of load. A bearing is a machine element that restricts relative motion to only the desired motion, and decreases friction between moving parts. It is an essential component in a compactor and is used for supporting the exciter shaft. Compaction is achieved by vibration of roller drum, which in turn is achieved by means of generated at the exciter shaft with an eccentric mass. During this process of generation of forced excitation, heat is generated at shaft to bearing interface. The current heat generation and dissipation paths for the bearing on the exciter shaft of the compactor were studied and calculated. Suggestions for heat dissipation optimization are provided. Various optimization methods were devised for heat dissipation to improve the wear as well as efficiency of the bearing and further testing is required for implementation of same.

The combustion and emission characteristics of a common-rail diesel engine fueled with diesel, propanol, and pentanol blends under low intake pressures

Due to the expansion of the global population and rapid economic growth, human activities at high-altitude regions are expected to grow. However, diesel engines are the main power sources for heavy-duty machinery, which can experience low combustion efficiency and high emissions due to the reduction of intake air mass. Adopting oxygenated fuels, such as alcohols, can be a possible solution to overcome these issues. Therefore, the study of the performance and emission characteristics of diesel engines fueled with diesel/alcohol blends under high-altitude conditions are necessary. To investigate the effects of low intake pressure and alcohol additives on the performance of diesel engines, the combustion and emission characteristics of a common-rail diesel engine fueled with diesel, propanol, and pentanol blends under different intake pressures were tested. Five intake pressures (1.2, 1.0, 0.8, 0.7 and 0.6 atm) were selected in this work. Propanol and pentanol (20% and 40% by volume) were added into diesel to achieve blends of Pr20, Pr40, Pe20, and Pe40. As compared to diesel, diesel/propanol and diesel/pentanol blends had longer ignition delays and shorter combustion durations. This means Pe20 and Pe40 can extend the operating range of diesel engines under low intake pressure conditions. Diesel/alcohol blends had higher NOx emissions but reduced soot emissions compared to pure diesel. With the same blend content, a higher blend ratio resulted in increased NOx emissions and lower soot emissions. The CO emissions of the tested fuels remained low (about 3 g/kWh) under higher intake pressures, while increasing dramatically when the intake pressure was lower than 0.8 atm. The HC emissions of the tested fuels also stayed low (around 0.2 g/kWh) when the intake pressure was over 0.7 atm.