Browse Topic: Heating, ventilation, and air conditioning systems (HVAC)
The automotive air-conditioning service ports task force conducted a field survey with MACS (Mobile Air Climate Systems Association) in June 2021. The scope of this survey was to determine the types of failures reported primarily at member service shops related to automotive air-conditioning service ports.
The increasing electrification of vehicles means that heating, ventilation and air conditioning systems have a broader range of tasks and a different priority assessment. In electric cars, air conditioning systems are not only responsible for cooling the passenger compartment, but also for controlling the battery temperature, particularly during rapid charging, which represents a high-load operating point. Furthermore, achieving high thermodynamic efficiency is desirable, as this directly impacts the range of electric cars. The elimination of the combustion engine as a major source of noise prioritizes the noise, vibration and harshness behavior of the refrigerant compressor for product selection. To investigate the vibration and acoustic behavior, as well as the fluid dynamic forces resulting from the cyclic compression principle of an electric refrigerant compressor, a test rig was developed that allows compressors to be operated and measured in isolation in an anechoic chamber under various defined operating conditions. This test rig has been expanded in two ways within the scope of this work. Firstly, the compressor can be either rigidly attached to a dead mass using a VDA mount or measured while suspended freely. Secondly, a new R744-compatible refrigeration circuit has been added to the test rig, enabling compressors operating with the environmentally friendly refrigerant CO₂, which has so far only been used by a few manufacturers in selected models, to be tested. Measurement results obtained using this test rig provide valuable insight into the vibration behavior and sound spectra of the refrigerant compressor's fluid, structural, and airborne noise when operating at different points.
The design, testing, and analysis of a Guided Autorotative Delivery System (GADS) for suppression of incipient wildfires is described. The GADS consists of an unpowered 1 m diameter rotor, a control unit, and a payload of 2.2 kg of fire suppressant powder. On release from a fixed-wing UAV, the rotor passively deploys and enters autorotation, decelerating the payload and allowing precise delivery of the suppressant using cyclic pitch control. A numerical model of the system was developed to calculate the trajectory of the GADS during rotor deployment and descent, in the presence of ambient wind and cyclic pitch inputs. A reduced-scale model of the rotor was tested in a wind tunnel, and an uncontrolled full-scale, 1.5 kg prototype of the GADS was fabricated and tested by dropping from a hovering quadcopter as well as a fixed-wing UAV. The full-scale drop experiments validated the deployment and autorotation stability of the system, and demonstrated that the GADS maintains descent velocities suitable for incipient fire suppression (≈ 5 m/s). Numerical predictions indicate that the GADS descent trajectory can be controlled with cyclic pitch in an ambient crosswind of at least 5 m/s (10 kts). Measurements captured during the drop tests using onboard instrumentation show good qualitative agreement with numerical predictions. Future work will include drop tests with remotely controlled cyclic pitch, followed by fully autonomous controlled descent. The study establishes design guidelines for guided autorotative systems and illustrates their potential for scalable UAV-based wildfire suppression or emergency response.
Climate control systems in Battery Electric Vehicles (BEVs), Plug-in Hybrid Electric Vehicles (PHEVs), and Extended Range Electric Vehicles (EREVs) rely on electrical energy to provide cabin heating. In winter conditions, the absence of waste heat from internal combustion engines necessitates increased energy consumption for thermal comfort, which directly impacts vehicle range. Conventional HVAC systems typically operate with a mixture of cold ambient air and recirculated cabin air. However, the proportion of recirculated air is limited due to windshield fogging risks, constraining energy-saving potential. To address this, MAHLE has developed the MAHLE HeatX Range+ that utilizes the thermal energy of exhaust cabin air, that would normally leave the passenger compartment through vehicle body vents, to precondition incoming fresh air, thereby reducing the heating load. This solution is engineered for scalable integration into existing HVAC architectures, allowing adaptation to varying vehicle packaging constraints and performance requirements. The concept is compatible with both direct and indirect refrigerant systems, including R1234yf, R744 and R290 ensuring broad applicability across future vehicle platforms. Experimental validation has been conducted at component, module and vehicle levels. Results confirm substantial heat recovery potential, leading to measurable reductions in HVAC energy demand and corresponding increases in driving range. This measure contributes to improved thermal efficiency and supports the broader objectives of sustainable mobility by enhancing energy utilization and passenger comfort in electrified vehicles.
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, zonal climate control, and integration with renewable energy sources. By implementing such energy-efficient solutions, EVs can achieve better range performance, improved user satisfaction, and greater environmental benefits. Modern EV climate control systems increasingly rely on intelligent features such as Auto mode, which dynamically adjusts fan speed, airflow direction, and temperature settings based on real-time cabin and ambient conditions. By leveraging sensor data and adaptive control algorithms, Auto mode optimizes thermal comfort while minimizing unnecessary energy expenditure. This automated regulation plays a crucial role in reducing HVAC-related power consumption, thereby contributing to overall range improvement and enhancing system efficiency without compromising passenger comfort. This study focuses on the development of three distinct Auto mode calibration levels for each set condition, designed to achieve the same cabin temperature with varying dynamic responses and energy consumption profiles. In Auto mode, the cabin temperature is regulated through intelligent control of compressor speed, blower speed, and evaporator temperature. While all Auto levels can maintain the desired setpoint, the time required to reach this temperature and the system’s responsiveness to sudden thermal loads can vary significantly. This study introduces three distinct calibration profiles, each engineered to achieve the same cabin temperature under different dynamic conditions and energy consumption levels. These profiles allow users to choose between faster thermal response or reduced power usage, effectively enabling a trade-off between immediate comfort and extended driving range
This paper explains the method of precooling of electric vehicle from grid connected charger reduce load on HVAC and improve the range. HVAC systems are integral part of a commercial EV bus. With the rise of ambient temperatures during various seasons, the load on HVAC System is increasing. Once an Electric vehicle is released from a depot for service, with an initial soaked up ambient vehicle, the HVAC system demands peak power for cooling the interiors which consumes a lot of battery power thus affecting the range. That cause the additional energy consumption required for precooling, which cannot be estimated as it is highly dependent on ambient temperature and range of the vehicle is also dependent on HVAC consumption during summer and peak loads. This paper is proposing a method that uses a special precooling mode which is activated depending on the selection of the vehicle route based on backend application running on cloud. The Application in the cloud checks if the vehicle is charging and also collects all the information about the SOC. This method will help in reduction in power demand from HVAC unit also helps in increasing the range of the vehicle.
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 Electric Drive system, DCDC, E-compressor and E-Heater; and intelligently allocates energy to each component, ensuring optimal performance. DEMS automatically selects the best drive mode and strategically manages energy distribution, prioritizing essential functions such as the drivetrain, followed by comfort features like heating or air conditioning, and luxury features like ambient lighting or seat massagers. This dynamic energy allocation is continuously adjusted to maximize efficiency, making EVs more efficient and extending their range. Simulations demonstrate that this approach can extend battery life and driving range, offering a promising solution for commercial EVs with existing battery technology. This strategy advances the sustainability and functionality of battery electric vehicles in modern transportation ecosystems.
This research analyzes the significance of air extractor on car door closing effort, especially within the context of highly sealed cabins. The goal is to measure their effectiveness in lowering pressure-induced resistance, study how the cut-out cross section and location affect performance, and its contribution to vehicle premium feel. Current vehicle design trends prioritize airtight cabin sealing for improving aerodynamic efficiency, NVH performance. This causes a problem in door closing operation. Air trapped while closing door creates transient pressure pulses. This pressure surge creates immediate discomfort to user i.e., Popping in Ears and requires high door closing force, and long-term durability problems in hinges and seals. In properly sealed cabins, air pressure resistance can contribute to 25% to 40% of total door closing force. Air extractors, usually installed in the rear quarter panels or behind rear bumpers, serve as pressure relief valves, allowing for a smoother airflow out of the cabin during such incidents. This passive system lowers door-closing effort, improves occupant experience, and safeguard structural components. A combination of CFD simulations, and real-world validations was employed to assess various air extractor configurations. Extractor size, location, flap design, and sealing levels of the vehicle were varied. Cabin pressure behavior and door closing force were evaluated under controlled and dynamic conditions. Comparative studies were also conducted across vehicle segments, including electric vehicles with high sealing requirements. Through these factors, this paper gives a holistic view to improve overall user experience as well as help to align with industry standards. The results have been backed with case studies as well as with simulation analysis to properly optimize the extractor design for new vehicles.
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 thermal modelling includes metabolic rate of heat production with effects of clothing in external ambient conditions. Once human thermal modelling in a controlled environment stabilized, LBM-based solver used to predict the convective heat transfer phenomenon. Thereafter, conduction and radiation effects were solved using a coupling approach in PowerTHERM. Physical tests conducted in a controlled environment of climate chambers. Simulation results obtained correlated with experimental data. Occupants’ thermal comfort evaluated using the Berkeley comfort model. The current process further highlights the impact of heater capacity variation on in-cabin air temperature and passenger comfort level. The proposed method is helpful in thermal comfort prediction for passenger vehicles at cold ambient comfort requirements, heater capacity, and airflow delivery system effectiveness. Current process is found more effective where heater capacity and thermal comfort balance prediction are sensitive to two heaters, discussed in this paper.
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 root cause analysis was conducted, including Transfer Path Analysis (TPA), evaluation of compressor fixation points stiffness, and dynamic noise signature analysis. The investigation revealed that the metallic noise was a combination of moaning and whining sounds, primarily caused by internal excitation forces within the compressor. These forces generated dominant excitations at high operating pressures, resulting in the observed tonal noise. Several countermeasures were explored, including changes to the compressor pulley ratio to decouple engine firing frequency excitations, modifications to the AC pipe bends to reduce excitation forces, and optimization of acoustic mass and compressor mounting stiffness. Collaboration work has been done with the supplier focused on fine-tuning the Mass Flow Control Valve (MFCV) settings [6] and adjusting compressor shaft tolerance. The most effective solutions were the compressor pulley ratio change and the modification of the compressor’s planetary plate angle, which together achieved an improvement of approximately 6 dB(A) in compressor order noise, significantly reducing customer-perceived annoyance. As a result, key NVH (Noise, Vibration, and Harshness) design rules have been established and implemented
The integration of Advanced Driver Assistance Systems (ADAS) into modern vehicles necessitates innovative solutions for interior packaging that balance out safety, performance, and ergonomic considerations. This paper introduces an inverted U-shaped steel tube cross car beam (CCB) as a superior alternative to traditional straight tube designs, tailored for premium vehicle instrument panels. The U-shaped geometry overcomes the limitations of straight tube beams by creating additional packaging space for components such as AR-HUDs, steering columns, HVAC systems, and electronic control units (ECUs). This geometry supports efficient crunch packaging while accommodating ergonomic requirements like H-point, eyeball trajectory, and cockpit depth for optimal ADAS component placement. The vertical alignment of the steering column within the U-shaped design further enhances space utilization and structural integrity. This study demonstrates that the inverted U-shaped CCB is a transformative solution for ADAS packaging, providing superior durability, crash performance, and knee injury mitigation compared to traditional straight tube designs. By addressing challenges such as crunch packaging, structural stiffness, and manufacturing efficiency, the U-shaped beam sets a new standard for global automotive platforms. The findings underscore its potential to revolutionize vehicle interiors, enabling advanced technology integration while maintaining safety and efficiency.
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