Browse Topic: Radiators
In automotive systems, efficient thermal management is essential for refining vehicle performance, enhancing passenger comfort, and reducing MAC Power Consumption. The performance of an air conditioning system is linked to the performance of its condenser, which in turn depends on critical parameters such as the opening area, radiator fan ability and shroud design sealing. The opening area decides the airflow rate through the condenser, directly affecting the heat exchange efficiency. A larger opening area typically allows for greater airflow, enhancing the condenser's ability to dissipate heat. The shroud, which guides the airflow through the condenser, plays a vital role in minimizing warm air recirculation. An optimally designed shroud can significantly improve the condenser's thermal performance by directing the airflow more effectively. Higher fan capacity can increase the airflow through the condenser, improving heat transfer rates. However, it is essential to balance fan capacity with energy consumption to achieve optimal performance. This study investigates the impact of varying these parameters on vehicle-level A/C performance and MAC Power Consumption. By systematically altering the condenser opening area, changing the shroud configuration, and adjusting the radiator fan capacity, we aim to find best conditions that enhance A/C performance and effect MAC Power Consumption. Experimental data were collected through a series of controlled tests, the results were analysed to decide the correlation between these variables A/C performance metrics such as average grill temperatures, refrigerant pressure and MAC Power Consumption. The findings provide valuable insights for automotive engineers and designers, highlighting the importance of these factors in achieving efficient as well as effective A/C systems in passenger vehicles.
This paper presents an advanced control system design for an engine cooling system in an internal combustion engine (ICE) vehicle. Building upon our previous work, we have derived models for crucial temperatures within the engine, including combustion wall temperature, coolant-out temperature, block temperature, as well as temperatures in external components such as heat exchangers and radiator. To accurately predict these temperatures in a rapid manner, we have utilized a lumped parameter concept with a mean-value approach. This approach allows for precise temperature estimation while maintaining computational efficiency. Given the complexity of the cooling system, we have proposed a linear time-varying (LTV) model predictive control (MPC) system to regulate the temperatures. This control system linearizes the model at each time step and applies linear MPC over the control and prediction horizons. By doing so, we effectively control the highly nonlinear and time-delayed system. Simulation results demonstrate the superiority and effectiveness of the proposed advanced engine cooling system. The control system can successfully regulate the temperatures within their desired range, showcasing its capability to optimize engine performance and ensure efficient cooling.
Cooling system for an IC engine, consisting of the Water pump (WP), Radiator and Fan, plays an important role in maintaining thermal efficiency of the engine and protects the engine from overheating. Based on the vehicle application requirement, Fan will be mounted directly either on Crankshaft or WP pulley. But wherever increase in Fan speed ratio are in demand, it is preferred to mount the Fan on WP pulley. So it important to understand the WP housing structural strength with respect to vibration loads contributed from Radiator Fan assembly. This paper presents investigation of Failure of WP Housing during engine validation at engine test bed with Electronic Viscous Fan, based on the different operating conditions of the engine and fan as per the validation cycle. While the accessories are loading and the corresponding stresses are high when the fan is engaged. But in the current case, the failure of WP housing happened only during Fan clutch disengaged condition. Experimental Frequency Response Function (FRF) were carried out to identify the mode shapes and resonant frequencies. Vibration on WP housing were compared with Fan engaged and disengaged condition to identify the critical frequency ranges that minimize vibrational impacts on the WP housing. The results indicate a significant correlation between Fan Blade Pass Frequency (FBPF) and vibrational amplitude on WP housing. By optimizing FBPF, it is successfully mitigated high vibration levels, thereby enhancing the structural integrity and operational reliability of the WP housing. In addition, the results of crack initiation points, strain gauge measurements, structural and modal analyses are examined to enhance the WP housing strength.
Customers expect more advanced features and comfort in electric vehicles. It is challenging for NVH engineers to reduce the vibration levels to a great extent in the vehicle without adding cost and weight. This paper focuses on reducing the tactile vibration in electric vehicle when AC is switched ON. Vibration levels were not acceptable and modulating in nature on the test vehicle. Electric compressor is used for cabin cooling and battery cooling in the vehicle. Compressor is connected to body with the help of isolators. Depending upon cooling load, the compressor operates between 1000 rpm and 8000 rpm. The 1st order vibration of compressor was dominant on tactile locations at all the compressor speeds. Vibration levels on steering wheel were improved by 10 dB on reducing the dynamic stiffness of isolators. To reduce the transfer of compressor vibration further, isolators are provided on HVAC line connection on body and mufflers are provided in suction and discharge line. With the above modifications, steering wheel vibration levels were reduced by ~ 2 dB. It is identified that radiator fan Pulse Width Modulation (PWM) frequency is also contributing to higher tactile vibration. Shifting PWM frequency to high frequency and stiffness increase on the fan motor casing has reduced the vibration levels by ~ 16 dB and cabin noise by ~ 2 dB (A). Alternative solutions like reducing of fan isolator stiffness is also explored. Blower vibrations contributing to steering wheel vibrations were reduced by controlling the unbalance on the blower. With all the modifications, tactile vibration levels are reduced considerably by ~ 20 dB. Modal criteria during design of compressor bushes and the NVH requirements during selection of fan PWM frequency to avoid higher levels of vibration during AC ON condition are explained.
Radiator is one of critical component used in automobiles which is used to cool engine under operating conditions. To cool down engine, a coolant is passed through engine block, where it absorbs heat from the engine. The hot coolant is then fed into inlet tank of radiator located either on top of radiator, or along one side from which it is distributed across radiator core through tubes to another tank on opposite end of radiator. As coolant passes through radiator tubes on its way to opposite tank, it transfers much of its heat to tubes which, in turn, transfer heat to fins that are lodged between each row of tubes. The fins then release heat to ambient air. Fins are used to greatly increase contact surface of tubes to air, thus increasing exchange efficiency. The cooled liquid is fed back to engine, and the cycle repeats. Due to the temperature gradient across the radiator, there will be thermal stress on the radiator especially on header joints. Another important area is header crimped location where high stress due to pressure load may occur. The present study involves study of radiator design by using coupled thermal-structural analysis. The analysis is carried out to check the structural integrity of radiator under thermal load as well as structural load conditions. The stress mainly is due to thermal gradient as well as pressure load which is effectively predicted using linear static coupled thermal-structural analysis and design modification based on the analysis reduced the stress on the radiator header part and increases the fatigue life of radiator. Neuber correction method predicted the nonlinear stress from the linear structural analysis result which predicts actual and life prediction also correctly. Dynamic analysis also carried out to check the strength of the assembly under dynamic load conditions which predict the stress on mounting locations. Hyper mesh used for the preprocessing of the analysis and ABAQUS used for the solver run and Hyper view for result visualization. The analysis result were validated with actual test result and found OK.
Vehicle thermal management system (VTMS) is a means of monitoring and controlling temperatures of vehicular components and aggregates to within optimum limits, thereby ensuring the proper functioning of the component or aggregate in an automobile. An integrated approach is required for developing VTMS, to satisfy the complex requirements of performance, reliability, fuel economy and human thermal comfort in modern vehicles. Fan motors and blowers play a crucial role in vehicle thermal management. These fan motors/ blower systems need to be designed in a manner such that there is minimum parasitic load on the prime mover. This work comprises performing Transient Powertrain Cooling (T-PTC) and Transient Air-conditioning (T-AC) simulation on a vehicle for prediction of parameters affecting fan operation of Condenser Radiator Fan Module (CRFM) during simulated city drive cycles. T-PTC model is built with addition of engine point mass, thermostat and heat conduction components to an existing steady state model. Dynamic solver is used to simultaneously solve for advection, convection and conduction within the fluid. T-AC model is built with a simple cabin model which helps to predict the average cabin temperature and average vent temperature along with the AC refrigerant discharge and suction pressures. T-PTC and T-AC models are integrated with fan logic sub-system and simulation is performed using 1-Dimensional Computer Aided Engineering (1D CAE) tool. Correlation of >96% accuracy is achieved with the physical test data for Fan Duty Cycle (FDC). Further, to check robustness of the 1D CAE model, FDC is predicted for the same vehicle program with a different CRFM. In this case, it is observed that, the predicted result correlates well with the physical test data with >96% accuracy. In this work, a robust simulation methodology is demonstrated, which can reduce cost and time in intensive physical test iterations and enable validation of different fan strategies for optimizing FDC in the early stages of vehicle development.
The automotive industry is a gigantic industry as millions of vehicles are running on the road and it’s growing at a rapid rate. The emissions are causing various global problems such as global warming, green house effects, air pollutions etc. due to the use of fossil fuels in abundance. This drives to think for alternative solutions, which are eco-friendly and having less or no emissions. The electric vehicles (EVs) are the most reliable solution as it is having high performance and efficiency with zero emissions. The evolution of EVs has fuelled the two-wheeler EVs industry to flourish at a fast pace. Li-ion battery and traction motor are the most important components in two-wheeler EVs and the thermal management for battery is more important for higher efficiency with longer life and better reliability along with the traction motor to have long range and better durability. This paper elaborates the radiator based thermal management solutions for the battery pack and the traction motor. It describes various technologies, which are being used for the thermal management of the battery pack and the traction motor. The cost and the packaging space are the bigger concerns for the OEMs (Original Equipment Manufactures) to not to go for heavier solutions, that’s why this paper discusses the integrated thermal management solutions, which is compact in size, light-weight and reliable for two-wheeler EVs for various vehicle-ranges. The liquid-based solutions have been taken into consideration to mitigate the thermal management issues in the battery pack and the traction motor in this paper. The recent incidents of the two-wheeler EVs catching fire on the road or during charging has put up the industry at the forefront to think for the reliable thermal management solutions, that’s why this research study has a very important role to play in eradicating the battery thermal issues as well as the traction motor thermal management issues.
Electric radiator fan is a vital component within IC and EV passenger vehicle cooling system. However, due to its operation, it induces noise and in-cab vibration affecting human comfort level. This paper primarily focus on FMS (Fan Motor Shroud) assembly induced steering wheel vibrations in a vehicle under idle + AC ON condition. The entire NVH performance was cascaded from vehicle level to component level to evaluate for high steering wheel vibration and its transfer path analysis. Unit level vibrations study was also carried out using a rigid rig under controlled conditions. Based on FMS vibration analysis, it was observed that fan blade rotating imbalance leads the high vibrations within system. Thus, a balancing method with higher precision and accuracy was used to measure and balance the fan under all operating conditions. Sensitivity analysis had been carried out for fan imbalanced boundary conditions and operating speeds. FMS assembly standalone imbalanced value and steering wheel vibration objective data and subjectively co-relation was established with the help of universal testing buck. Based on this methodology, a robust radiator fan imbalance target was set which in turn induces acceptable steering wheel vibration and thus, eventually maintains brand image and customer comfort associated with a particular model.
The dischargeable heat output and the cooling drag of motor vehicles are largely determined by the radiator size and the cooling air mass flow rate. In the present work, the effect of varying the radiator size on the cooling air requirement and the cooling drag of a motor vehicle is investigated. The starting point is the assumption that the transferred cooling power remains constant when the radiator size is changed. Based on the physical principles of heat and momentum transfer, a simple mathematical representation of the relationship between the radiator size, cooling air demand, and cooling drag is developed for this case, enabling an overall representation in clear diagrams. The results are validated by an experimental example from the literature. In addition, the application of the new equations is demonstrated in a real vehicle project where the aerothermodynamic challenge was a reduction in radiator size. The developed equations and diagrams allow a quick overview of the relationships and dependencies and enable rapid estimation of the effects on cooling-air demand and drag resulting from a change in radiator size.
GT-POWER and Simulink software are used to explore the influence of factors such as external temperature and radiator layout on the battery thermal management system, and prepare for the subsequent exploration of the joint simulation of the battery thermal management system under low temperature radiator threshold control and fuzzy control. The cooling and energy-saving effects of the fan and compressor using fuzzy control are analyzed. The results show that cooling the power battery with refrigerant is not affected by the external temperature. Under the condition of good temperature consistency of battery pack, compared with the threshold control, the fuzzy control strategy for fan and compressor speed can save about 23.1% and 14% of energy consumption respectively, which helps to improve the driving range of the vehicle.
The radiator as heat exchanger plays a very significant role in an engine cooling system by maintaining the coolant at an optimum temperature. The present study aims at improving the performance of an automobile radiator by using nano-coolants. Nano-scale particles have been tested and proven to have enhanced thermal conductivity than their bulk counterparts due to their increased surface area-to-volume ratio. Thus the nanoparticles dispersed in the base fluids called nanofluids are used as a radiator coolant to improve the performance of the radiator. Aluminum oxide (Al2O3)-based nanofluid at 0.04%, 0.08%, 0.15% by volume concentrations is used in two different base fluids, one being water and the other ethylene glycol (30%) (EG)-water mixture. Coolant is supplied at three different inlet temperatures at 40°C, 50°C, and 60°C and at five different flow rates ranging from 2 L/min to 6 L/min at an interval of 1 L/min. For all the experiments, the air velocity is maintained constant using a radiator fan (running at 1500 rpm). The experimental results showed that the overall heat transfer coefficient and coolant side heat transfer rate in the nanofluids can be enhanced considerably when compared to current-generation coolants like pure water and EG-water mixture. It has been observed that the addition of 0.08% volume fraction of alumina particles at all coolant flow rates and at all coolant inlet temperatures provided substantial enhancement in the overall heat transfer coefficient.
The purpose of the article is to evaluate the cooling performance efficiency of a Compressed Natural Gas (CNG) medium commercial vehicle with a viscous fan, fresh air cleaner, and choked air cleaner in comparison with limits prescribed in the Indian Standard (IS) 14557. Due to the increase in CNG availability, a shift is observed in the market demand for CNG vehicles. The earlier CNG vehicle duty cycle was limited to plain roads and some limited cities, but now vehicles are being used for a short trip to nearby hilly routes thereby shifting the application of the use of a CNG vehicle. CNG vehicles can now be operated in hilly areas where power and torque demand is maximum and operates at lower vehicle speeds and in lower gears. The subjected vehicles are designed for haulage applications to operate with conventional fixed fans, which are permanently engaged, and smaller radiators. The subjected vehicle was previously designed as per the requirements of the existing road application with a fixed fan and small radiator. Vehicle configuration was modified to the viscous fan and bigger radiator available as off-the-shelf components from the component suppliers. Viscous fans operate only when the coolant temperature goes beyond certain limits for better cooling performance of the engine, lower cabin noise, and higher fuel efficiencies. The main objective of this article is to compare the thermal behavior in different vehicle configurations by data acquisition and thereby establish the fact that subjected CNG vehicles can be used in difficult terrains due to broad CNG availability with maximum performance. The results obtained during the experiment with a smaller fixed fan and bigger viscous fan are at an ambient temperature above 35°C and, for a time, more than 5 minutes as specified in IS 14557. Base data is collected with the existing configuration of a vehicle with a small fixed fan and small radiator. Afterward vehicle configuration is changed to the viscous fan and bigger radiator and tested at conditions worse than as specified in the test standard, i.e., ambient temperature more than 35°C and, for a time, more than 5 minutes to ensure driveability in all terrains. Then the experiment is conducted at maximum power condition with fresh air cleaner and choked air cleaner. Another experiment is conducted to check the worst-case running in maximum torque condition with fresh air cleaner and choked air cleaner. After establishing the results in the first and second experiments, another two experiments were conducted to check the actual performance of the vehicle in plains and hilly route simulation as well.
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