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Numerical Investigation of Narrow-Band Noise Generation by Automotive Cooling Fans

Chalmers University of Technology-Omar Fares, Huadong Yao
Volvo Car Group-Chenyang Weng, Linus Zackrisson, Magnus Knutsson
  • Technical Paper
  • 2020-01-1513
To be published on 2020-06-03 by SAE International in United States
Axial cooling fans are commonly used in electric vehicles to cool batteries with high heating load. One drawback of the cooling fans is the high aeroacoustic noise level resulting from the fan blades and the obstacles facing the airflow. To create a comfortable cabin environment in the vehicle, and to reduce exterior noise emission, a low-noise installation design of the axial fan is required. The purpose of the project is to develop an efficient computational aeroacoustics (CAA) simulation process to assist the cooling-fan installation design. This paper reports the current progress of the development, where the narrow-band components of the fan noise is focused on. Two methods are used to compute the noise source. In the first method the source is computed from the flow field obtained using the unsteady Reynolds-averaged Navier-Stokes equations (unsteady RANS, or URANS) model. In the second method, the azimuthal modes of the flow field obtained using the steady RANS with the moving reference frame model are treated as the sound source. While the first method is able to resolve any…
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Installation Effects on the Flow Generated Noise From Automotive Electrical Cooling Fans

KTH CCGEx-Mikael Karlsson
Volvo Technology & Chalmers-Sassan Etemad
  • Technical Paper
  • 2020-01-1516
To be published on 2020-06-03 by SAE International in United States
With the electrification of road vehicles comes new demands on the cooling system. Not the least when it comes to noise. Less masking from the driveline and new features, as for example, cooling when charging the batteries drives the need for silent cooling fans. In this work a novel e-fan is studied in different generalized installations and operating conditions. The fans (a cluster configuration) are installed in a test rig where the operation could be controlled varying the speed, flow rate and pressure difference over the fan. On the vehicle side of the fan a generalized packaging space (similar to an engine bay for conventional vehicles) is placed. In this packaging space different obstruction can be placed to simulate the components and radiators used in the vehicle. Here generalized simple blocks in different configuration are used to provide well defined and distinct test cases. Of special interest are cases with poor inlet flow profile and the influence of this on the sound generation. The tests are currently in progress and results will be provided on…
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Innovative Rear Air Blower Design Application for Improving Cabin Thermal Comfort with improved Air Distribution and Air Quality.

Subros Ltd-Ravi Garg, Suraj maske, Yogendra Singh Kushwah
  • Technical Paper
  • 2020-28-0034
To be published on 2020-04-30 by SAE International in United States
In recent times, overall thermal comfort and air quality requirement have increased for vehicle cabin by multifold. To achieve increased thermal comfort requirements, multiple design innovation has happened to improve HVAC performance. Most of the advance and add on features like Multizone HVAC, dedicated rear HVAC, Automatic climate control, Advance Air filters, and Ionizers etc lead to increase in cost, power consumption, weight, and integration issues. Besides this in the vehicle with only front HVAC, airflow is not enough to meet rear side comfort for many cars in the B/C/SUV segment. This study aims to analyze the various parameters responsible for human thermal comfort inside a car with the focus on lightweight, low power consumption, compact Rear Blower to make passengers more comfortable by providing optimum airflow inline of mean radiant temperatures and cabin air temperature. The new design of Rear blower external surfaces has a set of air modifier surfaces in the direction of flow outlet. The second set of air modifier surfaces & an air deflator portion provided just upstream of outlet portion.…
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Methodology to quantify the undesirable effects of the localized inefficiency of heat pick-up in suction line on an automotive air-conditioning system

Y.S.Sarath Reddy
Tata Motors Ltd-Suresh Tadigadapa, Santosh Ghorpade, Ankit Shukla
  • Technical Paper
  • 2020-28-0036
To be published on 2020-04-30 by SAE International in United States
The automotive application places very special demands on the air conditioning system. As is the case with any other process, system efficiency is very important and the automotive air-conditioning application is no exception. While the characteristics of all the major components in the air conditioning system like compressor, condenser, evaporator and blower contribute to overall system efficiency, localized inefficiencies do play a part and so must be kept to a minimum, especially in this day and age when extra emphasis is being paid on sustainability. One such phenomenon that contributes to the system inefficiency is heat pick-up in suction line. Since the temperature at the evaporator-outlet is quite lower than ambient and also its surroundings (steering system pipes and hoses, engine, air intake pipes and so on), the refrigerant picks up heat as it moves along the suction line up to the compressor inlet. This heat pick-up is detrimental to the overall system performance. Even though most of the automotive HVAC engineers are fairly aware of the undesirable effects of heat pick-up in suction line,…
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Numerical Investigations on Heat Transfer and Flow Characteristics of Climate Control Systems in Electric Vehicles

Pranav Vikas India Pvt Ltd-Vijayaraghavan S, Govindaraj D
Pranav Vikas India Pvt Ltd.-Mahendravarman Radha
  • Technical Paper
  • 2020-28-0010
To be published on 2020-04-30 by SAE International in United States
Earth's surface temperatures would increase from 2.90 C to 3.40 C by the year 2100 due to global warming, leads to conceivable calamitous effects on human livelihoods, livestock, ecosystems and biodiversity. Overall globally several policies were made to reduce the carbon dioxide emission and other greenhouse gases. The transportation sector is one of the prominent sources of carbon dioxide emissions. On account of the significant emissions caused by conventional buses, migrating to electric buses which have zero tailpipe emissions for public transport fleets is essential. Taken into consideration of the energy density of traction batteries, and cost, energy utilized for HVAC applications should be optimized. Heat transfer and flow characteristics in the condenser and the evaporator zone of climate control system for electric buses were numerically studied and compared with experimental results. Grid independence and turbulence studies were carried out to develop the CFD methodology for this analysis. Air velocity and temperature was measured at different locations in the climate control system to calculate the flow and thermal performance. Fluid flow and heat transfer characteristics…
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Use of Partial Recirculation to Limit Build-Up of Cabin Carbon Dioxide Concentrations to Safe Limits per ASHRAE Standard-62

Calsonic Kansei North America Inc.-Gursaran Mathur
  • Technical Paper
  • 2020-01-1245
To be published on 2020-04-14 by SAE International in United States
Carbon dioxide exhaled by occupants remains within the cabin during operation of HVAC unit in recirculation mode. The CO2 inhaled by the occupants goes into their blood stream that negatively affects occupant’s health. ASHRAE Standard-62 (1999) specifies the safe levels of carbon dioxide in conditioned space for humans. The CO2 concentration limit per ASHRAE is 700 ppm over ambient conditions on a continuous basis. Based on the test data, at worst case scenario (idle condition where body leakage will be a minimal) results in CO2 concentrations of 1601, 2846, 4845 and 6587 ppm respective for 1 to 4 occupants in 30 minutes.Author has also conducted test by imposing ASHRAE standard-62. A controller was programmed for operating the blower unit’s intake door to go from recirculation to OSA mode when the measured carbon dioxide ppm level goes above 1100 ppm. The door stays in OSA mode until the cabin carbon dioxide falls to approximately 500ppm. By imposing these limits, the blower unit’s intake door cycles between 3 minutes to 6.5 minutes with four to one occupants…
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Development of Cooling Fan Model and Heat Exchange Model of Condenser to Predict the Cooling and the Heat Resistance Performance of Vehicle

Honda R&D Co., Ltd.-Yuichi Fukuchi, Kunihiko Yoshitake, Kazutaka Yokota
  • Technical Paper
  • 2020-01-0157
To be published on 2020-04-14 by SAE International in United States
The cooling performance and the heat resistance performance of commercial vehicle are balanced with aerodynamic performance, output power of power train, styling, the location of sensors, cost and many other parameters. Therefore, it is desired to predict the cooling performance and the heat resistance performance with high accuracy at the early stage of development. Three forms of heat transfer consist of conduction, convection and radiation. Among of these components, it is sometimes difficult to solve the thermal conduction accurately, because to prepare accurate shape and properties needs lots of time and efforts at the early stage of development. Therefore, the cooling performance of heat exchangers and the air temperature distribution in the engine compartment are predicted to access the cooling and the heat resistance performance of vehicle at the preliminary design stage. The air temperature distribution is dominated by the distribution of heat radiation on heat exchangers, the flow distribution which is produced by fans and thermal convection at the surface of parts in the engine compartment. For the case of middle or high vehicle…
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Probing Spark Discharge Behavior in High-speed Cross-flows through Modeling and Experimentation

Michigan Technological University-Mary P. Zadeh, Henry Schmidt, Seong-Young Lee, Jeffrey Naber
  • Technical Paper
  • 2020-01-1120
To be published on 2020-04-14 by SAE International in United States
This paper presents a combined numerical and experimental investigation of the characteristics of spark discharge in a spark-ignition engine. The main objective of this work is to gain insights into the spark discharge process and early flame kernel development. Experiments were conducted in an inert medium within an optically accessible constant-volume combustion vessel. The cross-flow motion in the vessel was generated using a previously developed shrouded fan. Numerical modeling was based on an existing discharge model in the literature developed by Kim and Anderson. However, this model is applicable to a limited range of gas pressures and flow fields. Therefore, the original model was evaluated and improved to predict the behavior of spark discharge at pressurized conditions up to 45 bar and high-speed cross-flows up to 32 m/s. To accomplish this goal, a parametric study on the spark channel resistance was conducted. Then, the parameters that best fit the experimental data were obtained using the least-squares fit technique. Results show that the model captured the spark discharge characteristics including the occurrence of the spark blowouts…
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Optimization of Control Parameters of Vehicle Air-Conditioning System for Maximum Efficiency

University of Zagreb-Ivan Cvok, Igor Ratkovic, Josko Deur
  • Technical Paper
  • 2020-01-1242
To be published on 2020-04-14 by SAE International in United States
Modern automotive heating, ventilation, and air-conditioning (HVAC) systems have multiple and often redundant actuators. In order to maximize HVAC efficiency, it is necessary to design a control system that optimally synthesizes multiple control actions while satisfying control set points and system hardware-related constraints. To this end, an optimization approach to control system design is proposed in this paper and demonstrated for a generic HVAC system. The paper first outlines a nonlinear 12th-order HVAC dynamics model that is based on the moving-boundary method. Then, the HVAC control system is defined, which combines proportional-integral (PI) feedback controllers commanding the compressor speed and expansion valve setpoints, and open-loop actions of condenser and blower fans. Next, a three-stage optimization approach is proposed consisting of the following steps: (i) rough optimization of all the aforementioned control inputs in an open-loop manner, (ii) feedback controllers’ parameter optimization, and (iii) refined optimization of the two open-loop control inputs while having the closed-loop controllers running. The first-stage optimization is aimed at finding a rough estimate of control vector containing all control inputs, which…
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CAE Cooling Module Noise and Vibration Prediction Methodology and Challenges

FCA US LLC-Ahmad ABBAS, Wael Elwali, Syed Haider, Suneel Dsouza, Michael Sanderson, Yoginder Segan
  • Technical Paper
  • 2020-01-1262
To be published on 2020-04-14 by SAE International in United States
In NVH domain, cooling module is an important subsystem in ground vehicles. Recently, with the development of small high output turbocharged internal combustion (IC) engines, cooling module noise and vibration has become more challenging. Furthermore, with plug-in hybrid electric vehicle (PHEV), in some cases the cooling fan could be operational while the IC engine is not running. This poses a significant challenge for cabin noise enhancement. Small turbocharged IC engines typically require higher cooling capacity resulting in larger fan size designs with higher speed. Accurate prediction of the imbalance loads generated by cooling fan and loads transferred to the body are critical for NVH performance of the vehicle. If NVH risk of cooling module operation is not well quantified and addressed early in the program, attempts to find solutions in post launch stage could be very expensive and not as effective. In this paper the static imbalance of the fan and motor assembly was studied and influence of couple imbalance was investigated. The results of static imbalance loading, coupled imbalance loading and combination of both…