With the increasing stringency of environmental protection regulations, the construction machinery industry is confronted with substantial pressure to reduce emissions. The pollutants emitted by traditional fuel-powered equipment have exerted a severe impact on the environment, while range-extended technology offers an effective solution to this problem. During operation, range-extended construction machinery is primarily powered by electricity, and the internal combustion engine is only activated to generate electricity when the battery charge is insufficient. Consequently, it can significantly reduce fuel consumption and exhaust emissions. Relevant data indicate that, compared with traditional fuel-powered construction machinery, range-extended construction machinery can reduce energy consumption by over 30%, nitrogen oxide emissions by 13% - 45%, and particulate matter emissions by 50% - 94%, thus better meeting the increasingly stringent environmental protection standards.
The R & D of dedicated range - extenders has entered the technologically challenging stage.
The operating environment of construction machinery is complex and changeable, and the working conditions are extremely harsh, which poses extremely high requirements for the R & D of dedicated range - extenders. During the R & D process, there are integration difficulties in multiple aspects such as the engine, electric motor, and electronic control system. Among them, the compactness of the spatial layout is one of the primary challenges. Due to the limited internal space of construction machinery, it is necessary to reasonably arrange numerous components such as the engine, electric motor, and electronic control system in a narrow space. This not only requires that the volume of each component be as small as possible but also demands a skillful design of the installation positions and connection methods among them to achieve compact and efficient space utilization.
The smoothness of power output is also a crucial issue. In the actual operation of construction machinery, the equipment needs to start, stop, accelerate, and decelerate frequently, with significant fluctuations in load. This requires the power output of the range-extender to respond promptly to changes in working conditions, maintaining stability and smoothness, and avoiding phenomena such as power interruption, jitter, or impact to ensure the operation accuracy and efficiency of construction machinery while reducing damage to the equipment structure.
The development of precise control algorithms is equally important. The electronic control system needs to accurately control the operating states of the engine and the motor based on real - time working conditions of construction machinery, such as load magnitude, driving speed, and battery charge, to achieve efficient collaboration between the two. For example, when the battery charge is sufficient and the load is small, the motor drive should be prioritized to reduce energy consumption; when the battery charge is insufficient or the load is large, the engine should be started promptly to generate electricity, and the output power of the engine and the motor should be reasonably allocated to ensure the normal operation of the equipment. This requires the development of highly intelligent and precise control algorithms that can quickly and accurately process a large amount of working condition data and make optimal control decisions.
Electromagnetic interference suppression is also a technical challenge that cannot be ignored. During the operation of engines and motors, strong electromagnetic interference is generated, which may affect the normal operation of the electronic control system, leading to problems such as distorted control signals and equipment failures. Therefore, advanced technical measures such as electromagnetic shielding and filtering need to be adopted to effectively suppress electromagnetic interference and ensure the stability and reliability of the electronic control system.
XCMG has been actively exploring in the research and development of dedicated range-extenders. They have taken the lead in collaborating with research institutions to conduct technological research, aiming to create a high-power density range extension system suitable for construction machinery. They have made significant progress in promoting the deep coupling design of dedicated engines and generators. By optimizing the structural design of the engines and generators, they have made the physical connection and working coordination between the two more closely, reducing energy loss during the transmission process and improving the overall efficiency of the system. For example, by adopting a new coupling device, a flexible connection between the engine and the generator was achieved, effectively reducing vibration and noise, and improving the stability and reliability of power transmission.
Intelligent control strategy achieves self-adaptive performance in all operating conditions
Drawing on the advanced experience from the passenger vehicle sector, the engineering machinery range-extended system is actively developing multi-mode intelligent control strategies to achieve adaptive operation in all working conditions. The core of this strategy lies in using over 130 condition-adaptation algorithms to dynamically optimize the start-stop of the range-extended engine, power distribution, and charging and discharging of the battery, enabling engineering machinery to maintain efficient operation in various complex working conditions.
The energy management system based on neural networks is an important innovation in this field. This system can accurately and real-timely identify the operating load of construction machinery, whether it is the powerful soil-breaking during excavation or the heavy lifting during hoisting, and can respond promptly. While ensuring that the power output meets the operational requirements, it effectively reduces energy consumption by 15% - 20%, significantly improving the overall efficiency of the system. For example, at a large construction site, an range-extended excavator equipped with a neural network energy management system can, during high-intensity excavation operations, adjust the power output of the generator and the discharge strategy of the battery in real-time according to the changes in excavation resistance.
When encountering softer soil layers, the system automatically reduces the power of the booster and prioritizes using battery power, thereby reducing fuel consumption. However, when digging hard rocks, it promptly increases the power of the booster to ensure sufficient power, while reasonably controlling the battery discharge depth to avoid excessive discharge that would damage the battery lifespan. Through this intelligent control, this excavator, during a one-month construction period, saves approximately 20% of fuel consumption compared to traditional fuel-powered excavators. At the same time, it reduces exhaust emissions and lowers pollution to the surrounding environment.
Furthermore, this intelligent control strategy can also be flexibly adjusted according to different working scenarios. When conducting indoor operations, due to the strict requirements for noise and emissions, the system will preferentially adopt the pure electric mode to meet the needs of environmental protection and quietness; while in long-term outdoor operations where charging is inconvenient, it will optimize the collaborative work of the range extender and the battery to ensure the continuous operation capability of the equipment.
The weakness in low-temperature performance can be addressed through multiple technological breakthroughs.
In the field of construction machinery, the issue of battery endurance in low-temperature environments has always been one of the key factors restricting its development. Especially in cold regions, such as Northeast China and Inner Mongolia, the winter temperatures often drop to minus several degrees or even lower. This poses a severe challenge to the battery performance and endurance of construction machinery. According to relevant data, in low-temperature conditions, the endurance range of traditional batteries may decline by more than 50%, seriously affecting the operation efficiency and application scope of construction machinery.
To solve this problem, the industry is actively exploring various technical means to achieve the coordinated optimization of thermal management and battery technology. Waste heat recovery technology is one of the key technologies among them. By ingeniously designing heat exchangers and other equipment, it is possible to effectively collect a large amount of waste heat generated during the engine's operation. This waste heat would otherwise be directly discharged into the atmosphere, causing energy waste. Now, it can be used to heat the battery. For example, a certain brand of construction machinery has adopted an advanced waste heat recovery system, introducing the engine's waste heat into the battery heating device, enabling the battery to maintain a more suitable working temperature in low-temperature environments, effectively reducing the degradation of battery capacity and thereby extending the range. Through actual testing, in an environment of -20℃, the range of this construction machinery has increased by about 20% compared to when the waste heat recovery technology was not used.
Pulse heating technology is also constantly evolving, providing new solutions for improving low-temperature performance. The pulse heating technology developed by Tsinghua University has performed exceptionally well. In an extreme environment of -30℃, it only takes a mere 5 minutes to heat the battery to room temperature, with a heating rate of up to 8℃/min. The principle of this technology is to utilize the characteristic of increased internal resistance of the battery at low temperatures, generating Joule heat through high-frequency charging and discharging to achieve rapid self-heating of the battery. Taking an electric loader that applied this pulse heating technology as an example, during winter low-temperature operations, it can quickly raise the battery temperature, enabling it to quickly reach the optimal working condition, significantly improving the startup speed and operational efficiency of the equipment, and effectively solving the problems of equipment difficulty in starting and low efficiency in low-temperature environments in the past.
Sodium-ion batteries, with their unique advantages, are gradually making their mark in the field of construction machinery. CATL's Xiongyao battery, which uses a lithium-sodium hybrid technology, has successfully achieved discharge at -40℃ and charging at -30℃, breaking the limitations of traditional batteries in low-temperature environments. In some special operation scenarios with extremely high requirements for low-temperature performance, such as polar scientific research and infrastructure construction in cold regions, sodium-ion batteries have demonstrated significant application potential. Compared with traditional lithium-ion batteries, sodium-ion batteries exhibit better ion conductivity and electrode reaction activity in low-temperature conditions, maintaining a high discharge capacity and charge-discharge efficiency, providing a strong guarantee for the stable operation of construction machinery under extreme low-temperature conditions.
The integration of heat pump systems is also a crucial measure to enhance low-temperature performance. Kelvin's Three-Source Heat Pump technology integrates air-source, motor-source and battery-source heat pumps, achieving efficient heat transfer and improved thermal quality, which can reduce winter energy consumption by 50%. During the road test in Tangshan, the three-source heat pump saved 40.5 kWh of electricity throughout the day, with an energy-saving rate as high as 15.9%. By combining the heat pump system with the battery thermal management system, the heat in the environment and the waste heat generated during equipment operation can be fully utilized to provide a warm heat source for the battery and the cab. This not only meets the heating needs of the equipment but also reduces additional energy consumption, further enhancing the equipment's endurance and operational performance in low-temperature environments.