The engine cooling fan drive is crucial for an engine as it ensures safe and efficient engine operation. In heavy-duty mobile machine, the engine cooling fan consumes a considerable amount of engine ...power. To meet high cooling demand a hydraulic fan drive is usually employed. A simple and cost-effective way is to use two fixed displacement hydrostatic units and a pressure relief valve where it has severe valve throttling losses. A more efficient way is to use a variable displacement pump to drive a fixed displacement motor. It eliminates valve throttling however the drive efficiency is still relatively low due to variable pump displacement control. Therefore, an engine cooling fan drive system with a power split hydraulic transmission was proposed in the previous study. The hydraulic transmission is a compact unit with both pumping and motoring functions. The fan speed is controlled by adjusting the transmission outlet pressure. Although previous results showed the system has relatively higher drive efficiency than conventional hydraulic fan drive at different fan speeds, the control design, and system dynamic performance have not yet been studied. Therefore, in this article, the control design of the cooling fan drive system with power split hydraulic transmission is studied. A feedforward controller based on transmission characteristics is designed to achieve better system performance. A hydraulic fan drive test bench is developed to evaluate system control design. The system dynamic performance with feedforward and feedback controls are compared through both simulation and experimental studies.
In order to support the development of the Geared turbofan （GTF） engine in China， the five-branch-power-split herringbone star gearbox for Fan drive gear system（FDGS） is studied. The manufacturing ...and assembling errors that affects the load sharing coefficient of the star gear system are analyzed. The calculation model for static load sharing coefficient of the star gear system is established. By calculating and analyzing the static load sharing coefficient of a star gear system test piece， the sensitivity of the manufacturing and assembling errors is obtained， the method of reducing the static load sharing coefficient by adjusting offset phase of star gears is proposed， and how to synchronize the eccentricity phase of planetary gear during assembly process illustrated by a star gear system test piece.
With the development of modern cities, the demand for cleaning glass curtain walls in urban skyscrapers is increasing, and therefore, many researches on facade cleaning robots have been carried out ...in the past few decades. In this article, a novel type of facade cleaning robot based on four-ducted fan is proposed. To improve the load capacity of the robot, the lifting and horizontal movement are, respectively, supported by an independent lifting mechanism and a lateral movement mechanism. Unlike the previous passive and active suction, the powerful suction power of the robot is provided by the four-ducted fan. Meanwhile, the obstacle-climbing force is caused by the forward of the four-ducted fan that improves the crossing obstacle ability. In addition, an incremental sliding mode algorithm is applied for controlling the posture when the robot crosses obstacles, which can ensure the stable performance of the cleaning robot under disturbance. Some simulations and experiments are conducted and the results demonstrate the effectiveness and robustness of the designed facade cleaning robot.
Abstract
The Electronic Viscous Fan Drive Clutch is one of the key components of cooling system in automotive sectors. It is more efficient than the current traditional bimetal operated Mechanical ...Viscous Fan Drive Clutch in terms of fan power consumption. The comparative change in fan power with both fan drives is studied and it is observed that with electronic fan clutch 86% reduction in fan power is achieved. In the current study an attempt is made to demonstrate the improvement in the cooling system in terms of ambient temperature of air and the coolant temperature. This is achieved through the complete driving cycles by maintaining unvarying temperature. Standard rise over ambient vehicle test with support of Vector CANape is utilized for testing and data recording. With use of electronic viscous fan drive there is direct proportional relation between coolant temperature and fan rpm. It also indicates that the system level temperatures are optimized to achieve higher efficiency in terms of thermal and fuel economy.
An efficient fan drive system based on a novel pressure-controlled hydraulic transmission (PCT) is studied in this paper. The new transmission uses a double-acting vane pump with a floating ring. By ...coupling the floating ring to an output shaft, the vane pump becomes a hydraulic transmission. The new transmission combines pumping and motoring functions in one unit, making it much simpler than a conventional hydrostatic transmission (HST). By controlling the pressure in the PCT, the output shaft torque and speed can be adjusted. In this paper, the fundamental principle of the new transmission is studied, with the focus on how the output shaft torque is influenced by the control pressure. To demonstrate its advantages, the new transmission is applied to a fan drive system, and the transmission efficiency is compared to an HST. Experimental results show that the input power of the fan drive system with the PCT is lower than that with an HST. By feeding the control flow to a hydraulic motor coupled to the output shaft of the PCT, a pressure-controlled hydromechanical transmission is constituted and the test result shows higher transmission efficiency than a PCT.
•A startup algorithm is design for AC synchronous machine.•The algorithm is implemented with a custom VHDL design.•The FPGA-based solution yields to a smooth acceleration ramp for the rotor velocity ...in the motor.•The AC synchronous machine is applied as a fan drive in a greenhouse.•The AC synchronous machine presents smooth transient currents.
In this work, a simplified startup method for AC synchronous machines is solved by means of a simplified algorithm based only in feeding the AC synchronous machine with stator voltages with a ramp frequency. The implementation of the algorithm along with the Space Vector Pulse Width Modulation technique is carried out by means of a Field Programmable Gate Array (FPGA) device, where Very High Speed Integrated Circuit, Hardware Description Language (VHDL) modules are custom designed. Experimental results were carried out for the ventilation of a greenhouse. The fan drive is turned on according to an existing control strategy designed for an optimal ventilation of the greenhouse. The designed algorithm with custom VHDL modules yields to a great performance for the fan drive in terms of smooth transient currents. The proposed algorithm was also implemented with an embedded microprocessor or softcore in an FPGA device for comparison purposes, yielding to same results. But in the case of optimal utilization of FPGA resources and the speed of execution of the algorithm, the VHDL modules custom design showed the best results.
In IRAQ, the air conditioners are the principal cause of high electrical demand. In summer, the outer temperature sometimes exceeds 500C which significantly effects on the A/C system performance and ...power consumed. In the present work, the improvement in mechanical and electrical performance of split A/C system is investigated experimentally and analytically. In this paper, performance and energy saving enhancement of a split-A/C system was experimentally investigated to be efficiently compatible with elevated temperature weathers. This improvement is accomplished via Smart Control System integrate with Proportional-Integral- Differential PID algorithm. The PIC16F877A micro-controller has been programmed with the PID and PWM codes to control the speed of the proposed DC condenser fan over wide range of speed, also it has been programmed to have a smart characteristics to protect the A/C system parts as the ability to detect a refrigerant leakage, condenser fan stop, and any obstacles for the fan air flow. A comparative study between the conventional and enhanced A/C system is performed. The results show that the proposed system exhibits better performance and saves more energy than the conventional one. The Coefficient of Performance (COP) of the split- A/C system are improved by about 20.56%.
Magnetorheological Fluid Fan Drive for Trucks Smith, Anthony L.; Ulicny, John C.; Kennedy, Lawrence C.
Journal of intelligent material systems and structures,
12/2007, Letnik:
18, Številka:
12
Journal Article, Conference Proceeding
Recenzirano
A magnetorheological fluid (MRF) fan drive prototype for automotive truck application is designed and tested for both performance and durability. A dual concentric gap with drum rotor design is ...chosen to meet the required torque capacity, packaging, and mass constraints. Finite element magnetostatic modeling is performed to size the electromagnetic circuit and achieve the desired flux density levels in the MR fluid gaps. The clutch is filled with a custom-formulated MR fluid. Performance testing shows excellent speed control and response. The required 40 N-m torque capacity is achieved along with low drag speed, which is a key design characteristic of the fan drive. The clutch successfully passed several 500 h durability tests in a test cell environment. Performance testing indicates that the MRF clutch maintains its required torque capacity with very little increase in drag speed over the duration of the tests indicating no fluid thickening issues. The total dissipated energy in these tests is about 3.8 GJ. The total specific dissipated energy for these tests is more than seven times higher than the 107 J/cm3 upper limit previously suggested in the literature.
This study proposes a closed‐loop fan drive system without using an encoder or current sensors. The cost and size of the fan drive system, therefore, are significantly reduced. By using ...low‐resolution three‐phase Hall‐effect position sensors, three‐phase sinusoidal pulse‐width modulation voltages are generated to control a permanent magnet synchronous motor (PMSM) that a fan is connected to. Two methods, including the back‐EMF estimation method and the impedance‐phase estimation method, are proposed to determine the input voltage amplitude and phase of the PMSM. A digital signal processor, TMS 320F28335, is used to execute the control algorithms. The proposed impedance‐phase estimation method is 25% more efficient than the back‐EMF estimation method at low‐speed operating range – below 1000 r/min. A detailed sensitivity analysis of the motor parameter variations is discussed. The implemented drive circuit, which is very compact, can be attached at the back of the PMSM and fan. Several experimental results are provided.
This paper presents static tests of a new unconventional propulsion unit for small aviation airplanes. Our laboratory stand – a fan drive demonstrator – enables us to compare various design options. ...We performed experiments to verify the propulsion functionality and a measurement procedure to determine the available thrust of the propulsion unit and its dependence on engine speed. The results used for subsequent optimization include the operating parameters of the propulsion unit, and the temperature and velocity fields in parts of the air duct.
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