Browse Topic: Air conditioning

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Optimization of Engine Cooling System for Improved Fuel Efficiency and Vehicle Marketability2026-01-0297To be published on 04/07/2026
Effective thermal management in internal combustion engines is essential for meeting increasingly stringent global emissions regulations and fuel efficiency standards. This paper presents a comprehensive solution to enhance engine thermal management performance by addressing key system aspects, including coolant circuit architecture, Integrated Thermal Management Module (ITM) control strategies, port-specific flow management, zero-flow operation, and standardization of HVAC (Heating, Ventilation, and Air Conditioning) settings. The research was conducted on a newly developed engine platform, where a suite of advanced thermal management measures was applied and verified through both vehicle and bench testing. Key improvements included reducing the thermal mass of the coolant circuit to enable faster warm-up of the engine and major components, as well as refining ITM control logic through linear mapping and signal filtering for more precise target coolant temperature regulation. Enhanced
Lee, ChangJoo, LEE, KyuMin, Kim, Seonyeong, Nam, Choonho, YOO, JiHun
Investigation of the Blockage Phenomenon in Closed Wall Wind Tunnels During the Testing of Bluff Automotive Bodies with Small Wakes in Yawed Configurations2026-01-0607To be published on 04/07/2026
The difficulties of testing a bluff automotive body of sufficient scale to match the on-road vehicle Reynolds number in a closed wall wind tunnel has led to many approaches being taken to adjust the resulting data for the inherent interference effects. But it has been very difficult to experimentally analyze the effects that are occurring on and around the vehicle when these blockage interferences are taking place. The present study is an extension of earlier works by the author and similarly to those studies uses the computational fluid dynamics analysis of five bodies that generate relatively small wakes to examine the interference phenomena in solid wall wind tunnels and the effects that they have on the pressures, and forces experienced by the vehicle model when it is in yawed conditions up to 20 degrees. This is accomplished by executing a series of CFD configurations with varying sized cross sections from 0.4% to 14% blockage enabling an approximation of free air conditions as a
Gleason, Mark, Riegel, Eugen
Methodology for Shower Water Management in Electric Car Applications2026-28-0068To be published on 02/12/2026
All automotive vehicles with enclosed compartments must pass the shower test standard - IS 11865 (2006). One of the most severe and critical areas of water leakage is “water entry into HVAC (heating, ventilation, and air conditioning) opening”. Excess water flow at high-pressure conditions and seepage during long-time low-pressure conditions could potentially have a significant impact on water entry inside the HVAC suction cutout given on BIW (body in white) and subsequently into the cabin. The present study clearly indicates that for making leak proof HVAC opening (suction interface), it is crucial for the structure of BIW plenum, plenum applique, and its sealing components to be robust enough to effectively collect and divert the water during rainy seasons.
Gunasekaran, Mohanraj, Namani, Prasad, Ramaraj, Rajasekar, Junankar, Ashish, Raju, Kumar
Development of Smart Climate Control with Multiple Level Auto Calibrations2026-28-0008To be published on 02/12/2026
Electric Vehicles (EVs) are rapidly transforming the automotive landscape, offering a cleaner and more sustainable alternative to internal combustion engine vehicles. As EV adoption grows, optimizing energy consumption becomes critical to enhancing vehicle efficiency and extending driving range. One of the most significant auxiliary loads in EVs is the climate control system, commonly referred to as HVAC (Heating, Ventilation, and Air Conditioning). HVAC systems can consume a substantial portion of the battery's energy—especially under extreme weather conditions—leading to a noticeable reduction in vehicle range. This energy demand poses a challenge for EV manufacturers and users alike, as range anxiety remains a key barrier to widespread EV acceptance. Consequently, developing intelligent climate control strategies is essential to minimize HVAC power consumption without compromising passenger comfort. These strategies may include predictive thermal management, cabin pre-conditioning
Mulamalla, Sarveshwar Reddy, SV, Master Eniyan, M, Nisshok, Anugu, Anil, E A, Muhammed, Guturu, Sravankumar
Environmental Control Systems for RotorcraftARP292D (Current)1/21/2026
This SAE Aerospace Recommended Practice (ARP) discusses design philosophy, system and equipment requirements, environmental conditions, and design considerations for rotorcraft environmental control systems (ECS). The rotorcraft ECS comprises that arrangement of equipment, controls, and indicators which supply and distribute dehumidified conditioned air for ventilation, cooling and heating of the occupied compartments, and cooling of the avionics. The principal features of the system are: a A controlled fresh air supply b A means for cooling (air or vapor cycle units and heat exchangers) c A means for removing excess moisture from the air supply d A means for heating e A temperature control system f A conditioned air distribution system The ARP is applicable to both civil and military rotorcraft where an ECS is specified; however, certain requirements peculiar to military applications—such as nuclear, biological, and chemical (NBC) protection—are not covered. The integration of NBC
AC-9 Aircraft Environmental Systems Committee
Driving Thermal Intelligence – Pioneering Digital Twin-Driven Hardware-In-Loop for Smart Climate Control Modules2026-26-03801/16/2026
Thermal comfort is increasingly recognized as a vital component of the in-vehicle user experience, influencing both occupant satisfaction and perceived vehicle quality. At the core of this functionality is the Climate Control Module (CCM), a dedicated embedded Electronic Control Unit (ECU) within automotive HVAC system [6]. The CCM orchestrates temperature regulation, airflow distribution, and dynamic environmental adaptation based on sensor inputs and user preferences. This paper introduces a comprehensive Hardware-in-the-Loop (HIL) [3] testing framework to validate CCM performance under realistic and repeatable conditions. The framework eliminates the dependencies on physical input devices—such as the Climate Control Head (CCH) and Infotainment Head Unit (HU)—by implementing virtual interfaces using real-time controller, and Dynamic System modelling framework for plant models. These virtual components replicate the behaviour of physical systems, enabling closed loop testing with high
More, Shweta, Shinde, Vivek, Turankar, Darshana, Patel, Dafiya, Gosavi, Santosh, Ghanwat, Hemant
Improve the Electric Vehicle Range by Using the Climate Control Setting in Economy Mode at Hot Climatic Conditions2026-26-01721/16/2026
Electric vehicles (EVs) have surged in popularity in recent years due to their environmental benefits. The influence of range on air conditioning (AC) power consumption is a critical concern for electric vehicle (EV) owners, particularly in warmer climates. Overcoming obstacles such as a limited vehicle range is necessary for the increased use of electric-powered automobiles. Cabin heating and cooling demand for climate control consumes more energy from the main battery and has been revealed to significantly reduce vehicle range. During peak cooling or heating, the overall power consumption of the AC system takes almost 50% of the energy used for traction. The average reduction in driving range caused by air conditioning (heating and cooling) approximates 33%. The energy usage of an electric vehicle can be considerably decreased by switching the climate control setting to economy mode. The AC system will operate more effectively, enabling the vehicle to save energy and extend its range
Mulamalla, Sarveshwar Reddy, Anugu, Anil, E A, Muhammed, Ummiti, Kumar, M, Nisshok, Choudhary, Ankit
Cabin Modelling Approach in 1D Simulation for Studying the Impact of Partial Recirculation in Warmup for BEV at Extreme Cold Ambient Conditions2026-26-04501/16/2026
The inclusion of the cabin in HVAC simulations gained more importance with the introduction of BEV’s. Thermal management and efficiency being in the forefront, exploration for the possible opportunities to reduce the energy consumption for meeting the comfort of passengers gained importance. The energy consumed by the Electric coolant or air heaters for heating the cabin at extreme cold ambient temperatures to deliver similar comfort to that of an ICE version is 2 to 3 times that of the energy required for cooling the cabin in a high ambient condition. Even during the sizing of HVAC system, if traditional method of ambient or fresh air conditions is considered for calculating the requirements, the result is we would require a product which will have unrealistic performance demand. Hence to explore different possibilities for studying the system, usage of recirculation air was considered as one of the options. This paper talks about the approach followed in creating the cabin model in
Veerla, Eswar, Subramanian, Karthik
Quantifying the Energy Consumption of HVAC Operation and Its Impact on the Range of Electric Buses Across Diverse Climatic Conditions2026-26-02041/16/2026
Electric buses (e-buses) are essential to sustainable public transport, but their real-world efficiency and range are heavily affected by auxiliary systems, particularly the Heating, Ventilation, and Air Conditioning (HVAC) system. This study investigates how ambient temperature variations and HVAC loads influence energy consumption, range, and efficiency in e-buses operating under diverse climatic conditions. The methodology combines field data collection from urban e-buses across seasons—including extreme summer and winter—with controlled laboratory testing. Field measurements included ambient temperature, HVAC demand, vehicle speed, state of charge (SOC) variation, and energy consumption. These inputs were used to develop real-world duty cycles, replicating actual thermal loads, passenger profiles, idling periods, and driving patterns. In the laboratory, these cycles were simulated using a chassis dynamometer and environmental chamber, with HVAC systems tested at controlled ambient
Vishe, Prashant, Dalela, Saurabh, Saraswat, Shubham, Joshi, Madhusudan
Cabin Heat-Up Thermal Assessment for Human Comfort in Passenger Car2026-26-04081/16/2026
The HVAC (Heating, Ventilation, and Air conditioning) system is designed to fulfil the thermal comfort requirement inside a vehicle cabin. Human thermal comfort primarily depends upon an occupant’s physiological and environmental condition. Vehicle AC performance is evaluated by mapping air velocity and local air temperature at various places inside the cabin. There is a need to have simulation methodology for cabin heating applications for cold climate to assess ventilation system effectiveness considering thermal comfort. Thermal comfort modelling involves human manikin modeling, cabin thermal model considering material details and environmental conditions using transient CAE simulation. Present study employed with LBM (Lattice-Boltzmann Method) based PowerFLOW solver coupled with finite element based PowerTHERM solver to simulate the cabin heat up. Human thermal comfort needs physiological modelling; thus, the in-built Berkeley human comfort library is used in simulation. Human
Baghel, Devesh Kumar, Kandekar, Ambadas, Kumar, Ravi, Dimble, Nilesh
Real-Time Range Optimization for Selected Destinations by Dynamic Energy Management Strategy (DEMS) in BEVs2026-26-01681/16/2026
The automotive industry has undergone significant transformation with the adoption of electric vehicles (EVs). However, the inadequate driving range is still a major limitation and to tackle range anxiety, the focus has shifted to energy management strategies for optimal range under different driving conditions. Developing an optimal energy management algorithm is crucial for overcoming range anxiety and gaining a competitive edge in the market. This paper introduces Dynamic Energy Management Strategy (DEMS) for electric vehicles (EVs), designed to optimize battery usage and extend the driving range. Utilizing vehicle digital twin model, DEMS estimates energy consumption across Eco, Normal, and Sports driving modes by analyzing vehicle velocity profiles and pedal inputs. By calculating actual battery consumption and identifying excess power usage, DEMS operates in a closed loop to periodically assess the power gap based on real-time vehicle conditions, including HV components like the
Dey, Supriyo, Venugopal, Karthick Babu, Penta, Amar, Kumar, Rohit, Arya, Harshita
Resolution of Automotive Air Compressor Noise in Low Powered ICE Vehicles2026-26-03141/16/2026
The interior noise and thermal performance of the passenger compartment are critical criteria for ensuring driving comfort [1]. This paper presents the optimization of air conditioning (AC) compressor noise, specifically for the low-powered 1.0 L - ICE engine paired with a 120 cc IVDC compressor. This combination is quite challenging due to the high operational load & higher operating pressure. To enhance better in-cabin cooling efficiency, compressor’s operating efficiency must be improved, which necessitates a higher displacement of the compressor. However, increased displacement results in greater internal forces which leads to more structure-borne induced noise inside the cabin. For this specific configuration, the compressor operating pressure reached up to 25 bars under most driving conditions. During dynamic driving scenario, a metallic tonal noise from the compressor was reported in a compact vehicle segment. It is reported as very annoying to passengers inside. A comprehensive
John Britto, Vijay Antony, Maluganahalli-Dharmappa Madhusoodan Sr, Madhusoodan, Natarajasundaram, Balasubramanian
Research on Adaptation and Reliability Testing Methods for Electric Vehicles under Southeast Asian Climatic Conditions2025-99-024012/23/2025
This paper explores the adaptability and reliability testing methods of electric vehicles under the unique high-temperature and high-humidity climate conditions in Southeast Asia. The focus of the research here is on five key performance evaluation contents, namely reliability driving test, charging performance test, range assessment, air conditioning cooling efficiency, and in-vehicle air quality monitoring. Relying on a meticulously designed experimental plan, standardized testing procedures, and comprehensive data analysis, this paper assesses the performance of electric vehicles under extreme environmental conditions. The research results show that the climate in Southeast Asia poses significant challenges to the battery systems, powertrains, and thermal management systems of electric vehicles. Based on empirical results, some improvement suggestions are made to support the deployment and application of electric vehicles in this region.
Wang, Weijie, Deng, Tianhao, Wu, Yilong, Zang, Haonan
Alternative to PFAS Ban: Impact on the Systems and Implementation Challenges2025-36-010212/18/2025
In early of 2023 the European Union began the process of banning the so-called Per- and polyfluoroalkyl substances, with a total elimination forecast for 2035. Currently, the refrigerant gas used by automakers is the R1234yf, a substitute for the R134a as a refrigerant with zero degree of ozone layer destruction, developed to meet the European directive 2006/40/EC that came into force in 2011. It requires all new car platforms for sale on the continent to use a refrigerant in their air-conditioning system with a Global Warming Potential below 150. The alternatives studies for the replacement of R1234yf are R744 (CO2) and R290 (Propane). The first is characterized by being a non-flammable gas and has a working pressure of 6 to 12 times higher than the current one. The second has the characteristic of having working pressure similar to R1234yf, but it is a highly flammable gas. This work focuses on the analysis of the two alternative gases to R1234yf, exploring their characteristics
Ariza, Valquíria Rezende, Erberelli, Diego Pivatto, Silva, Pedro Henrique Moraes da, Miyauchi, Edison Tsutomu
Refrigerants Selection for Automotive Air Conditioning System in Tropical Climates2025-36-014312/18/2025
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Oliveira Dias, Vinícius José de, Barbieri, Paulo Eduardo Lopes, Moreira, Thiago Augusto Araújo, Santos, Alex Henrique, Freitas Paulino, Tiago de
Prediction of Compressor Torque due to Swash Angle Change by Using Multi Body Simulation2025-28-040110/30/2025
Compressor is one of rotating component in AC system and function of the compressor is to increase the pressure of refrigerant and circulate the refrigerant across the system. Swash plate compressor is generally used in automotive AC application due to its light weight and compact size. Torque required to operate the compressor is very important and Compressor torque for specific capacity need to be evaluated based on simulation result. For this, simulation tools are effectively used. Modeling and simulation are the key enablers to improve the design and development process. They are extensively used throughout the development cycle. MBD based simulation is more commonly used which gives better understanding of the movement of kinematic part. Reaction forces from the result will help in providing information for the CAE analysis. Many parameters like reaction forces, torque and power varying with shaft angle of rotation is predicted using MBD and result is analyzed. Rigid and Flexible
Parayil, Paulson
Design and Analysis on Integrated Thermal Management Solution for Electric Vehicles2025-28-041810/30/2025
Thermal Management System (TMS) for Battery Electric Vehicles (BEV) incorporates maintaining optimum temperature for cabin, battery and e-powertrain subsystems under different charging and discharging conditions at various ambient temperatures. Current methods of thermal management are inefficient, complex and lead to wastage of energy and battery capacity loss due to inability of energy transfer between subsystems. In this paper, the energy consumption of an electric vehicle's thermal management system is reduced by a novel approach for integration of various subsystems. Integrated Thermal Management System (ITMS) integrates air conditioning system, battery thermal management and e-powertrain system. Characteristics of existing integration strategies are studied, compared, and classified based on their energy efficiency for different operating conditions. A new integrated system is proposed with a heat pump system for cabin and waste heat recovery from e-powertrain. Various cooling
K, Muthukrishnan, S, Saikrishna, Mahobia, Tanmay, Vijayaraj, Jayanth Murali
IHX Technology and Its Effectiveness in Automotive AC Performance2025-28-043010/30/2025
The Internal Heat Exchanger (IHX) is an important component in modern car air conditioning (AC) systems, particularly in AC lines. It increases cooling efficiency by transferring heat from the high-pressure liquid refrigerant to the low-pressure vapor. By using this technology, refrigerant sub-cooling and superheating improve, resulting in higher cooling performance, lower energy usage, and less strain on the compressor. It improves vehicle fuel economy and a longer lifespan of AC components. Also, IHX prevents liquid refrigerant from entering the compressor, reducing the danger of damage and increasing system reliability. This optimization helps to maintain consistent refrigerant flow, reduces energy consumption, and improves the overall Coefficient of Performance (COP). The implementation of an IHX technology in AC lines results in more compact, streamlined system designs, which allow for better temperature management, faster response times, and lower cooling loads. An IHX can boost
Dudeja, Kailash, Singh, Saniya
Performance Investigation of Air Conditioning System in Electric Vehicle by Fault Detection and Diagnosis2025-28-035310/30/2025
The study emphasizes on detection of different faults and refrigerant leakage as well as performance investigation of automobile air conditioning system for an electric vehicle by varying various operating conditions. A refrigerant leak in an EV isn't just an inconvenience; it's a potential threat to vehicle range and usability, lifespan and health of the expensive battery pack, overall vehicle performance, passenger safety and comfort, component longevity (motor, power electronics), environmental responsibility. Due to the refrigerant leakage, the cooling system performance degrades, and components tend to fail. Because of that this study is focusing on deriving an algorithm to have an early detection of fault and leakage in the vehicle. The performance of the system is predicted for actual conditions of operation encountered by the automobile air conditioning system. The objective of the present work includes predicting the causes and effects of refrigerant leakage in AC system of
Bezbaruah, Puja, Yadav, Ankit, Pilakkattu, Deepak
Maximizing Range with Advanced Air Conditioning Optimization and Energy Management2025-28-036410/30/2025
Widespread adoption of electric vehicles (EVs) is hindered by "range anxiety," a major concern for consumers. A primary contributor to this issue is the significant energy consumption of the Heating, Ventilation, and Air Conditioning (HVAC) system, which can account for 15-40% of a vehicle's total energy demand, directly reducing its practical driving range. Using the 1D simulation tool GT-SUITE, this research provides a comparative analysis of two distinct HVAC architectures: a conventional air-cooled condenser (ACC) and a proposed liquid-cooled condenser (LCC). The performance of both hardware systems was evaluated under two control strategies a Proportional-Integral (PI) controller and a basic On/Off controller—to identify the optimal configuration. The results advocate that optimizing the system's architecture and control logic yields a substantial improvement in the Coefficient of Performance (COP) ranging from 47% to 128% compared to the baseline ACC/On-Off configuration, with a
T R, Rakshith, Yadav, Ankit
Simulation-Driven Improvement of Temperature Linearity in Dual Layer HVAC Systems2025-28-038810/30/2025
The Heating, ventilation, and air conditioning (HVAC) industry is rapidly growing, particularly in the automotive sector since they are integral to maintaining passenger comfort in vehicles by regulating the internal temperature. This growth has led to an increased demand for highly optimized and efficient HVAC systems for a uniform temperature distribution in vehicles. However, achieving this in the cabin remains a challenge due to the complex airflow dynamics within the HVAC system. A critical factor in ensuring uniform temperature distribution for year-round performance is maintaining temperature linearity within specified limits, which is essential for user comfort. Temperature linearity refers to the temperature differential between duct outlets when air is distributed through multiple vents, such as those aimed at the face and feet. This differential typically ranges from 15°C to 20°C, varying based on customer and manufacturer specifications. The flap angle significantly
Madaan, Ashish, Kumar, Ravi, Dangwal, Raj
Integrated Topology, Shape and Size Optimization-Application in Automotive Design and Manufacturing2025-28-037510/30/2025
CAE (Computer Aided Engineering) optimization plays a pivotal role in various industries to gain a competitive edge. CAE optimization is essential in several industries, such as automotive, aerospace and consumer electronics, etc., concentrating on enhancing component structural design. The process helps in addressing complex design challenges, including weight reduction, material usage efficiency and operational effectiveness. This paper presents applications for an integrated form shape, size and topology optimization approach of structural systems by using CAE tools. For the present study, CAD (Computer Aided Design) was prepared using CATIA V5 followed by meshing in Hyper-mesh 2022.3 version software. Optistruct was used as a solver tool. Modal analysis was performed to extract the natural frequencies of vibration and respective mode shapes. According to the results of the frequency response function study performed on the automobile air conditioning condenser, based on low-stress
Mehra, Akanksha, Parayil, Paulson
Noise Mitigation Techniques Off-Highway Vehicle HVAC Unit2025-28-037810/30/2025
Noise generated by a vehicle’s HVAC (Heating, Ventilation, and Air Conditioning) system can significantly affect passenger comfort and the overall driving experience. One of the main causes of this noise is resonance, which happens when the operating speed of rotating parts, such as fans or compressors, matches the natural frequency of the ducts or housing. This leads to unwanted noise inside the cabin. A Campbell diagram provides a systematic approach to identifying and analyzing resonance issues. By plotting natural frequencies of system components against their operating speeds, Test engineers can determine the specific points where resonance occurs. Once these points are known, design changes can be made to avoid them—for example, adjusting the blower speed, modifying duct stiffness, or adding damping materials such as foam. In our study, resonance was observed in the HVAC duct at a specific blower speed on the Campbell diagram. To address this, we opted to optimize the duct design
Trivedi, Arpita, Kumar, Ravi, Madaan, Ashish, Shrivastava, Pawan
A Novel Approach to Enhance Compressor Life in Passenger Vehicle MAC Systems2025-28-040910/30/2025
Compressor durability is a critical factor for ensuring the long-term reliability of Mobile Air Conditioning (MAC) systems in passenger vehicles. This study presents a software based strategy for enhancing compressor life using Smart Fully Automatic Temperature Control (FATC), requiring no additional hardware. The proposed approach leverages existing inputs from the FATC and Engine Management System (EMS) to intelligently manage compressor operation, with a focus on addressing challenges related to prolonged non-usage. In extended inactivity scenarios such as during cold weather, vehicle exportation, storage, or breakdowns, lubrication oil tends to settle in the compressor sump, leaving internal parts dry. Sudden reactivation at high engine speeds under such conditions can cause increased friction, wear and even compressor seizure. To mitigate this, an intelligent reactivation protocol has been developed and integrated into the Climate Control Module (CCM). This protocol continuously
Deshmukh, Ganesh, Chotaliya, Bhavy, Kulkarni, Shridhar, KHAIRE, DATTATRAY, Jaybhay, Sambhaji, Joshi, Gaurav, Shah, Geet
Study of Impact of Bumper Opening, Radiator Fan Capacity and Shroud Sealing on the Cabin Cooling Performance and MAC Power Consumption in ICE Vehicle2025-28-039210/30/2025
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
Nayak, Akash, lingampelly, Rajaprasad, Neupane, Manoj, Mittal, Sachin, Kumar, Mukesh, Umbarkar, Shriganesh
Design Strategies for Integrating a Quieter Refrigeration Handling System in Automotive HVAC2025-28-043210/30/2025
In both internal combustion engine (ICE) and electric vehicles, Heating, Ventilation, and Air Conditioning (HVAC) systems have become significant contributors to in-cabin noise. Although significant efforts have been made across the industry to reduce noise from airflow handling systems, especially blower noise. Nowadays, original equipment manufacture’s (OEMs) are increasingly focusing on mitigating noise generated by refrigeration handling systems. Since the integration of refrigeration components is vital for the overall Noise Vibrations and Harshness (NVH) refinement of a vehicle, analysing the impact of each HVAC component during vehicle-level integration is essential. This study focused on optimizing the NVH performance of key refrigeration components, including the AC compressor, thermal expansion valve (TXV), suction pipe, and discharge line. The research began with a theoretical investigation of the primary noise and vibration sources, particularly the compressor and TXV
Titave, Uttam Vasant, Kalsule, Shrikant, Naidu, Sudhakara
Automated Air Filter Clog Detection in Passenger Vehicles- Enhancing Cabin Air Quality2025-28-042010/30/2025
Air filters are critical to vehicle Heating, Ventilation, and Air Conditioning (HVAC) systems, ensuring cabin air quality by trapping dust particles that accumulate over time. However, conventional clogging diagnostics—such as physics-based simulations, empirical models or manual inspection—are often too complex or impractical for in-vehicle deployment. To address this, we present a simple and practical diagnostic approach for real-time detection of cabin filter clogging by continuously monitoring the pressure drop across the filter–evaporator assembly at five blower speed settings. Baseline pressure drop values were established for a clean filter in a production-spec Passenger car and the clogged filter threshold was defined by a 10% reduction in airflow. This corresponded to calibrated pressure drop values of 83, 108, 169, 212 and 256 Pa for blower speeds 1 to 5, respectively. These thresholds were programmed into the vehicle’s climate control ECU. During operation, when the measured
Raj, Rohit, Mohite, Yashwant, Naik, Niranjan, Ghate, Pravin
A Method to Enhance Cabin Air Quality with Energy Efficiency in parallel for AC System in Electric Vehicle2025-28-042810/30/2025
During air conditioning operation in automobiles (ICE and EVs), cabin air is predominantly recirculated to reduce heating and cooling loads of occupant space. However, prolonged recirculation of air leads to deteriorated cabin air quality. Simply introducing fresh air to improve air quality is inefficient, as external air conditions are unpredictable and may negatively affect energy consumption as well as cabin interior air quality. Moreover, even in recirculation mode under low ambient conditions where de-humidified air is available outside, energy usage increases due to the dual operation of the electric compressor (e-Compressor) and the Positive Temperature Coefficient (PTC) heater especially in case of Electric Vehicle. In this dual-mode scenario, the e-Compressor maintains a low evaporator temperature for effective air dehumidification, while the PTC heater supplies sensible heating to achieve the desired cabin comfort. In case of ICE vehicle the heater is coolant based and free
Kumar, Sunny, Venu, Santosh, Raj, Shivam, Khan, Farhan
Study of Possibility of Deletion of Side Demister by Optimization of Nozzle Defroster Shape to Secure the Outside Rear View Mirror Visibility2025-28-038310/30/2025
Efficient clearing of frost formed on automotive side window glass during cold conditions is crucial for maintaining visibility and ensuring passenger safety. Conventional systems often employ dedicated side demisters, which increase system complexity, production costs and vehicle weight. This study explores an alternative approach to defrosting side window glass by optimizing airflow from the defroster, thus eliminating the need for separate side demisters. The Study leverages optimized airflow dynamics and strategic design of defroster to direct a portion of the air towards the side glass. Computational Fluid Dynamics (CFD) simulations and actual Tests to analyze the airflow patterns, temperature gradients, and defrosting efficiency of this configuration. Results indicate that the front defroster airflow can effectively clear frost from the side windows, achieving comparable performance to conventional side demisters. Key design parameters, including defroster geometry and airflow
Kushwaha, Mayank, Bhangale, Shekhar, Mittal, Sachin, Kumar, Mukesh, Umbarkar, Shriganesh
A Smart Multi-Disciplinary Approach to Evaluate Thermal Insulation Impact on Automobile Mobile Air Conditioning System Performance2025-28-042510/30/2025
Automotive mobile air conditioning (MAC) systems rely on effective thermal insulation to maintain cabin comfort and energy efficiency. However, insulation materials degrade over time due to thermal cycling and environmental exposure, impacting overall system performance. This study investigates the effects of reducing insulation material density (GSM) in critical areas such as the engine firewall, plenum, roof and door panels on MAC system efficiency. A multi-disciplinary approach combining basic engineering calculations, frontloading CAE simulations and targeted experimental testing was employed. Initial calculations provided directional input for cabin heat load analysis, guiding early-stage design decisions. Simulation models were used to predict the impact of insulation reduction on cooling performance, energy consumption and component durability, reducing reliance on iterative physical testing. Experimental validation was then conducted selectively, focusing on critical areas to
Kulkarni, Shridhar, Deshmukh, Ganesh, Joshi, Gaurav, Nayakawadi, Uttam, Shah, Geet, Jaybhay, Sambhaji
Risk Assessment of Delayed MAC Compressor Engagement on Occupant Thermal Comfort2025-28-039910/30/2025
Mobile air conditioning (MAC) systems play a critical role in ensuring occupant thermal comfort, particularly under extreme ambient conditions. Any delay in compressor engagement directly affects cabin cooldown performance, impacting both perceived and measured comfort levels. This study assesses the thermal comfort risks associated with compressor engagement delays of 6.5 seconds and 13 seconds under varying ambient conditions. A comprehensive frontloading approach was employed, integrating 1D CAE simulations with objective and subjective experimental testing. Initial simulations provided insights into transient cabin heat load behavior and air distribution effectiveness, enabling efficient test case selection. Physical testing was conducted in a controlled climatic chamber under severe (>40°C) ambient condition, replicating real-world scenarios. Objective metrics, including cabin air temperature, vent temperature and cooldown rates, were measured to quantify thermal performance
Kulkarni, Shridhar, Deshmukh, Ganesh, Joshi, Gaurav, Shah, Geet, Jaybhay, Sambhaji
Research on the Control Method of Electric Vehicle Air-Conditioning System Based on Human Thermal Comfort2025-01-506510/2/2025
For electric vehicles (EVs), the automotive air-conditioning system is the most energy-consuming auxiliary system and the key to the thermal comfort of the passenger compartment. How to reduce the energy consumption of EVs’ air-conditioning system and improve passenger comfort is one of the focuses of EVs’ air-conditioning system research. This article proposes a method to integrate the passenger cabin thermal comfort into the control of electric vehicle air-conditioning system. A coupled thermal model of the passenger compartment, air-conditioning system and battery thermal management system of EVs is established for the control of the air-conditioning system, and the effects of the air supply parameters of the air-conditioning system and the zonal air supply control strategy of the air-conditioning system on the thermal comfort of the passenger compartment are analyzed. Based on this coupled thermal model, an air-conditioning control strategy is established with the thermal comfort
Xu, Xiang, Yan, FuWu, Wang, Wei, Liu, Shuqi, Wang, Yuan
Effect of Pressure Losses and Reynolds Number on Active Grille Shutter Characteristics and Its Prediction2025-01-50599/10/2025
In the present article it is investigated why active grille shutters (AGS) can have very different aerodynamic characteristics, ranging from progressive to strongly degressive, and which factors influence them. For this purpose, the authority concept known from the field of heating, ventilation, and air-conditioning (HVAC) is referred to. According to this theory, the control characteristics of dampers depend primarily on the ratio of the pressure losses at the fully open damper to the pressure losses of the rest of the system. The adaptation of the concept to the automotive field shows that, in addition to the pressure losses, the geometry of the cooling air ducting plays a decisive role in motor vehicles. The effect of driving speed and fan operation on the characteristic curves is also being investigated. In addition, authority theory can also be used to derive the conditions under which the opening characteristic curve of an AGS provides a good prediction of the real characteristic
Wolf, Thomas
Research on Validation and Research Platform for Automotive Air-Conditioning Control Strategy2025-01-50589/10/2025
In order to improve the efficiency of verification and optimization of control strategies for air-conditioning systems, a thermal management platform is established based on a rapid control prototyping (RCP) approach in the article. The platform is composed of a HVAC hardware bench, a real-time control system, and a control software model. This article describes the overall architecture of the platform, the control strategy, and an efficient method for development and optimization of air-conditioning control strategies. The cooling and heating modes of the air conditioner are tested. The results show that the control strategy can be directly modified via the platform to improve the performance of the whole system. The experimental results show that after modifying the control strategy, the cooling effect of the air conditioner is optimized and the cooling time is reduced by 10.6%. The CLTC cycle is also tested in this work to verify the dynamic control performance of the air
Liu, Shuqi, Yu, Yilong, Wang, Wei, Wang, Yuan, Zhang, Yilun, Xu, Xiang
Simulation Based Dynamic Thermal Emulation Unit for Thermal Preconditioning and Emulation of Hardware Components on the Thermal Testbed2025-24-01379/7/2025
Electrification of vehicles plays an important role in the transformation process towards sustainable mobility in the individual and transport sector. As a result, new challenges must be met during the development process regarding the vehicles overall energy management system. A key challenge is the development of thermal management systems to optimize overall vehicle efficiency and to minimize ageing effects of the powertrain components while maintaining passenger comfort. Efficiency and ageing effects are highly dependent on the conditioning state of the powertrain components due to their high thermal sensitivity with simultaneously narrow thermal operating limits. Comfort functions like cabin air conditioning must be fulfilled as well, which must be considered by the thermal management system. To develop innovative solutions for thermal management systems at an early stage of the development process, thermal emulation can be used to substitute hardware components. Therefore
Weimer, Niko, Hohenberg, Günter, Beidl, Christian, Fiore, Luis, Stenger, Erik, Seib, Rico
Simulation-Based Investigation and its Experimental Validation of the Thermal Behaviour of a Battery Electric City Bus2025-01-02667/2/2025
Electrification of city busses is an important factor for decarbonisation of the public transport sector. Due to its strictly scheduled routes and regular idle times, the public transport sector is an ideal use case for battery electric vehicles (BEV). In this context, the thermal management has a high potential to decrease the energy demand or to increase the vehicles range. The thermal management of an electric city bus controls the thermal behaviour of the components of the powertrain, such as motor and inverters, as well as the conditioning of the battery system and the heating, ventilation, and air conditioning (HVAC) of the drivers’ front box and the passenger room. The focus of the research is the modelling of the thermal behaviour of the important components of an electric city bus in MATLAB/Simscape including real-world driving cycles and the thermal management. The heating of the components, geometry and behaviour of the cooling circuits as well as the different mechanisms of
Schäfer, Henrik, Meywerk, Martin, Hellberg, Tobias
R-1234yf (HFO-1234yf) Recovery/Recycling/Recharging Equipment for Mobile Air-Conditioning SystemsJ2843_202506 (Current)6/17/2025
This SAE Standard applies to equipment to be used with R-1234yf refrigerant only. It establishes requirements for equipment used to recharge R-1234yf to an accuracy level that meets Section 9 of this document and purity levels defined in SAE J2099. Refrigerant service equipment is required to ensure adequate refrigerant recovery to reduce emissions and provide for accurate recharging of mobile air-conditioning systems. Equipment shall be certified to meet all performance requirements outlined in this document and international/regional construction and safety requirements as outlined in this document.
Interior Climate Control Service Committee
HFC-134a Refrigerant Electronic Leak Detectors, Minimum Performance CriteriaJ2791_202505 (Current)5/16/2025
This SAE Standard provides testing and functional requirements to meet specified minimum performance criteria for electronic probe-type leak detectors, so they will identify smaller refrigerant leaks when servicing all motor vehicle air conditioning systems, including those engineered with improved sealing and smaller refrigerant charges to address environmental concerns and increase system efficiency. This document does not address any safety issues concerning their design or use.
Interior Climate Control Service Committee
Tonal Noise Investigation of Automotive HVAC Systems: A Hybrid Method2025-01-00275/5/2025
There is no need to recall how the electrification trend of transport facilities has tightened the requirements around acoustic comfort. Within the automotive industry, these targets are more challenging for Heating, Ventilation and Air Conditioning systems for which passengers are in the frontline of noise emissions inside the car cabin. The complexity of the requirements and specifications set by car manufacturers and suppliers stems from a dual aspect. First is quantitative based on the sound pressure level, whether it's the overall level or 1/3 octave band spectra. The second is purely subjective, based on the perceived noise quality by stakeholders and final customers worldwide. During development phases, low tonal noises are frequently encountered on these systems which might induce discomfort to the passengers. The experimental investigations usually point to an aerodynamic origin, which prompted this research activity. The purpose of this work is to analyze and understand the
Bennouna, Saad, Alaoui, Mohamed, Henner, Manuel
Method for Removal of Refrigerant from Mobile Air-Conditioning System to Quantify Charge AmountJ2762_202505 (Current)5/3/2025
This standard provides an overview of results and requirements needed to remove refrigerant from a mobile air-conditioning system for determining refrigerant emissions (leakage). This reclaim procedure for use on fleet vehicles in a field service environment should produce an accuracy and repeatability sufficient to determine refrigerant loss within 2 g.
Interior Climate Control Service Committee
Air Conditioning Service Procedures for Off-Road Work Machines and Agricultural Tractors Using HFC-134a or HFO-1234yf RefrigerantJ3126_202504 (Historical)4/14/2025
This SAE Recommended Practice is intended to provide technicians with safe and efficient techniques and general equipment recommendations for servicing mobile air conditioning systems in off-road, self-propelled work machines as defined in SAE J1116 and tractors and machinery for agriculture and forestry as defined in ASABE standard ANSI/ASAE S390. Both refrigerants HFC-134a (R-134a) and HFO-1234yf (R-1234yf) are covered. Many service procedures are similar for both refrigerants, but recovery, recycling, charging, and electronic leak detection tools can be unique to each refrigerant.
HFTC6, Operator Accommodation
Investigation of the Blockage Phenomenon in Closed Wall Wind Tunnels During the Testing of Bluff Automotive Bodies with Large Wakes in Yawed Configurations2025-01-87864/1/2025
The difficulties of testing a bluff automotive body of sufficient scale to match the on-road vehicle Reynolds number in a closed wall wind tunnel has led to many approaches being taken to adjust the resulting data for the inherent interference effects. But it has been very difficult to experimentally analyze the effects that are occurring on and around the vehicle when these blockage interferences are taking place. The present study is an extension of earlier works by the author and similarly to those studies uses the computational fluid dynamics analysis of three bodies that generate large wakes to examine the interference phenomena in solid wall wind tunnels and the effects that they have on the pressures, and forces experienced by the vehicle model when it is in yawed conditions up to 20 degrees. This is accomplished by executing a series of CFD configurations with varying sized cross sections from 0.4% to 14% blockage enabling an approximation of free air conditions as a reference
Gleason, Mark, Riegel, Eugen
Control Trajectory Optimization of Electric Vehicle Heat Pump-Based Cabin Heating System2025-01-81444/1/2025
Optimal control of battery electric vehicle thermal management systems is essential for maximizing the driving range in extreme weather conditions. Vehicles equipped with advanced heating, ventilation and air-conditioning (HVAC) systems based on heat pumps with secondary coolant loops are more challenging to control due to actuator redundancy and increased thermal inertia. This paper presents the dynamic programming (DP)-based offline control trajectory optimization of heat pump-based HVAC aimed at maximizing thermal comfort and energy efficiency. Besides deriving benchmark results, the goal of trajectory optimization is to gain insights for practical hierarchical control strategy modifications to further improve real-time controllers’ performance. DP optimizes cabin inlet air temperature and flow rate to set the trade-off between thermal comfort and energy efficiency while considering the nonlinear dynamics and operating limits of HVAC system in addition to typically considered cabin
Cvok, Ivan, Deur, Josko
Battery Thermal Management System for PHEV by using Air Conditioning Heater System2025-01-81724/1/2025
Toyota Motor Corporation pursuing an omnidirectional strategy that includes battery electric vehicle (BEV), plug-in hybrid electric vehicle (PHEV), and fuel cell electric vehicle (FCEV) to accelerate electrification. One of the technical challenges with our xEV batteries which feature good degradation resistance and long battery life, is that regenerative braking cannot be fully effective due to the decrease in regenerative power in some situations, such as low battery temperature. For the electrified vehicles with an internal combustion engine such as PHEVs, the solution has been running the engine to increase deceleration through engine braking during coasting. PHEVs are expected to extend their cruising range and enhance EV driving experience as "Practical BEVs". While increasing battery capacity and enhancing convenience, the restrictions on EV driving opportunity due to low battery temperature may negatively affect PHEV’s appealing. As an alternative, introducing a battery heater
Hoshino, Yu
Power Loss Estimation in Poly-V Belts for Micro and Mild Hybrid Powertrains Using the Generalized Maxwell Model2025-01-83164/1/2025
In modern automotive powertrains, the front-end accessory drive represents a crucial subsystem that guarantees the proper functioning of micro and mild hybrid configurations and auxiliary vehicle functionalities. The motor/generator (12 V or 48 V), the air conditioning compressor and other accessories rely on this subsystem. Therein, the poly-V belt is the main transmission mechanism. From an efficiency standpoint, its behavior is usually represented through slip and elastic shear phenomena. However, the viscoelastic nature of the compounds that constitute the belt layers demand a more detailed approximation of the loss mechanisms. The quantification of such losses allows evaluating the performance of the e-machine integrated in the powertrain. This work models the belt through a lumped-parameter time-domain model, where domains are discretized into multiple elements and represented through the generalized Maxwell model. Loss contributions due to bending, stretching, compression and
Galluzzi, Renato, Amati, Nicola, Bonfitto, Angelo, Hegde, Shailesh, Zenerino, Enrico, Pennazza, Mario, Staniscia, Emiliano
Emissions Savings from Efficient Mobile Air-Conditioning (MAC) Systems in Passenger Vehicles2025-01-81564/1/2025
Mobile Air-Conditioning (MAC) systems are a substantial source of energy consumption and CO₂ emissions in passenger vehicles, particularly for electrified vehicles under real-world operating conditions. Enhancing the efficiency of such systems is imperative to achieving greater energy efficiency and maintaining occupants’ comfort. In recognition of their significance, MAC systems can be classified as eco-innovative technologies under EU Regulation 2019/631, effective from 2025. This study lays the groundwork for a methodology to calculate CO₂ savings from eco-innovative MAC systems in passenger cars. The approach compares CO₂ emissions between baseline and eco-innovative vehicles under active and inactive MAC systems. Literature-derived indicative ambient conditions are applied to reflect realistic MAC usage scenarios in Europe. The testing protocol follows the WLTP procedure under controlled ambient conditions, including temperature, humidity, and solar irradiation, which can either
Di Pierro, Giuseppe, Currò, Davide, Gil-Sayas, Susana, Fontaras, Georgios
Development of Ceramic Humidity Regulator (CHR) Using Honeycomb Type PTC Heater to Improve Electric Vehicle Driving Range in Winter2025-01-81774/1/2025
With Rapid growth of Electric Vehicles (EVs) in the market challenges such as driving range, charging infrastructure, and reducing charging time needs to be addressed. Unlike traditional Internal combustion vehicles, EVs have limited heating sources and primarily uses electricity from the running battery, which reduces driving range. Additionally, during winter operation, it is necessary to prevent window fogging to ensure better visibility, which requires introducing cold outside air into the cabin. This significantly increases the energy consumption for heating and the driving range can be reduced to half of the normal range. This study introduces the Ceramic Humidity Regulator (CHR), a compact and energy-efficient device developed to address driving range improvement. The CHR uses a desiccant system to dehumidify the cabin, which can prevent window fogging without introducing cold outside air, thereby reducing heating energy consumption. A desiccant system typically consists of two
Hamada, Takafumi, Shinoda, Narimasa, Konno, Yoshiki, Ihara, Yukio, Ito, Masaki
Research on the Thermal Performance of Thick Film Heater for Electric Vehicle Battery2025-01-81544/1/2025
A specific thick film heater (TFH) for electric vehicles is investigaed in this study, and its three dimensional heat tansfer analysis model is estab-lished. The heat transfer and fluid performance of the TFH is analyzed using a computational fluid dynamics soft-ware. The performance of TFH is measured on a test bench, and the measured data is used to validate the developed model. Using the established model, the heating efficiency of TFH is studied for different inlet temperatures and flow rates, and the influence of the fin spoiler structure on TFH heating efficiency and the heating board temperature is investigated. The result indicates that the spoiler structure has a large effect on the board heating temperature, but has little effect on the heating efficiency. An orthogonal experimental design method is used to optimize the design of the fins and water channels, and the purpose is to reduce the board heating temperature for preventing over burning. Under the 25°C inlet
Guan, Wenzhe, Guo, Yiming, Wu, Xiaoyong, Wang, Dongdong, Shangguan, Wen-Bin
Automatic Generation of HVAC Ducting System Designs Using Topology and Shape Optimization2025-01-86564/1/2025
In this paper, the topology and shape optimization of a vehicle Heating, Ventilation, and Air Conditioning (HVAC) system is presented. The CFD and optimization methodologies are implemented within AcuSolve™ software. The topology optimization algorithm computes the geometry, where the design domain is parameterized with a field of porosity design variables which indicates the material, fluid or solid, throughout the domain. The optimization is performed using the continuous adjoint approach by the Galerkin Least Squares solver on which the AcuSolve™ solver is based. The design is further improved by using shape optimization. To optimize the geometrical shape, a combination of smooth perturbations, in terms of so called morph shapes, are used to deform the geometrical shape in the optimization algorithm. To this end, a parameterization of the design space is done using a moderate number of design variables, each associated with a morph shape. The two optimization phases are connected by
Papadimitriou, Dimitrios, Sandboge, Robert
Modeling and Control Strategies of the Thermal Management System for Electric Vehicles2025-01-81904/1/2025
The electric vehicle thermal management system is a critical sub-systems of electric vehicles, and has a substantial impact on the driving range. The objective of this paper is to optimize the performance of the heat pump air conditioning system, battery, and motor thermal management system by adopting an integrated design. This approach is expected to effectively improve the COP (Coefficient of Performance) of cabin heating. An integrated thermal management system model of the heat pump air conditioning system, battery, and motor thermal management system is established using AMEsim. Key parameters, such as refrigerant temperature, pressure, and flow rate at the outlet of each component of the system are compared with the measured data to verify the correctness of the model established in this paper. Using the established model, the impact of compressor speed on the heating comfort of the cabin under high-temperature conditions in summer was studied, and a control strategy for rapid
Zhang, Min, Li, Liping, Zhou, Jianhua, Huang, Yu, Zhen, Ran, Shangguan, Wen-Bin
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