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With the global competitiveness in automotive segment, vehicle manufacturers are facing steep competition in reducing the overall cost, development time without compromising the performance and quality. So the development of each aggregate, system and sub-system also need to be faster than ever before. Being an automotive AC manufacturer, it is quite obvious that the AC system should also be developed within short span of time. However it is quite imperative to meet or exceed the cooling requirement. Hence a novel approach of combining the 1-dimensional (1D) and 3-dimensional (3D) simulation is developed in order to evaluate and predict the cabin cool down before the actual prototypes are being made. The present study employs the combined approach of predicting the system level performance through 1-D simulation and predicting the airflow field inside the vehicle using 3D simulation. System level simulation was carried out in Kuli software.

Automotive heating ventilating and air conditioning (HVAC) noise is becoming a big concern area as the demand for acoustic comfort increases day by day. Vehicles are manufactured in recent years with quieter powertrain, reduced body leakage, better suspension. The other quieter technologies like electrification, hybridization of vehicle further complicate the whole subject of vehicle cabin noise issue. The HVAC noise is the major noise source inside the cabin. Hence designing a HVAC with very low sound pressure level is quite challenging and poses many difficulties in meeting other basic performances due to certain trade-off while meeting the noise requirement. However in recent years engineers have done extensive research and come up with various feasible and non-feasible solutions in order to reduce the HVAC noise significantly.

Heating, ventilation and air conditioning systems play a crucial role in our day-to-day activities. With rise in global warming, leading to climate change, HVAC unit is the need of the hour. With average temperatures on the rise, it is quite imperative that the unit provides better thermal comfort to the passengers. Off-road vehicles like tractor, is also no exclusion. Tractor drivers have to experience adverse weather conditions out in the open field. Thus it is quite fundamental that sufficient airflow reaches every point inside the driver cabin, ensuring proper cool-down. To ensure proper distribution of airflow inside the cabin, optimization of HVAC unit needs to be properly carried out. The present study shows how an HVAC of an off-road vehicle is properly optimized with the help of Computational Fluid Dynamics. STAR-CCM+ v2021.2.1 is used as solver for the simulation.

With the transition from Internal Combustion Engines Vehicles (ICEVs) to Electric or Hybrid Electric Vehicles (EVs/HEVs), most of the system aggregates and system parameters need to be redefined and recalibrated. This is mainly due to the change in power and transmission system. One of the critical system aggregates is heating ventilating and air-conditioning (HVAC) system as it directly impacts the car interior noise (other than passenger comfort) across all speed ranges. At low speed, interior noise becomes more annoying due to HVAC and electromagnetic noise from traction motor. However, at high speed other auxiliary noise sources are added up to the overall noise sources. Hence it becomes necessary to design and develop the HVAC system which should produce no abnormal noise and overall noise becomes low. The advancement of numerical simulation plays an important role in finalizing the HVAC design and also provides better insight of the products.

Vehicle air conditioning and heating system is one of the most important part of an automobile system. Computational fluid Dynamics (CFD) is widely used to predict air flow rates and distribution in such Heating Ventilation and Air Conditioning (HVAC). Commercial CFD codes such as FLUENT and STAR-CCM+ are widely used in simulation for industrial research. But usage of these software comes with a heavy cost. Cost is one such parameter which industries try to bring down, without compromising on the deliverables in product development. OpenFOAM is one such license free, open source code that can be used to modify and compile its code based on the needs and the physics of the problem in hand. This study assessed the performance of airflow magnitude and distribution in an HVAC using OpenFOAM. The results between STAR-CCM+ and OpenFOAM were compared in terms of grid-independent solutions using various scalar and vector plots.

As the automotive industry is transitioning from conventional engine driven to electric battery driven, many of the vehicle aggregates are getting re-engineered and changing accordingly. Being air-conditioning manufacturer one of the aggregates that needs attention and focused effort is the Heating Ventilation and Air Conditioning system (HVAC). Acoustic comfort of electric vehicle gets impacted due to the HVAC noise in absence of engine and hence other noise sources becomes prominent which were earlier masked by the engine noise. It is important to understand the HVAC noise sources for implementing right countermeasures for masking the noise. There are three methods of noise source identification namely acoustical duct method, cocooning or lead covering method and near field method. Out of these method, acoustical duct method and near field methods are used for minor and major noise identification in this study.

In order to ensure a comfortable space inside the cabin, it is very essential to design an efficient heating ventilating and air-conditioning (HVAC) system which can deliver uniform temperature distribution at the exit. There are several factors which impact on uniformity of temperature distribution. Airflow distribution is one of the key parameter in deciding the effectiveness of temperature distribution. Kinematics links and linkage system typically termed as ‘mechanism’ is one of the critical sub-systems which greatly affects the airflow distribution. It is not the temperature uniformity but also the HVAC temperature linearity also depends on airflow distribution. Hence the design of mechanism is incomparably of paramount importance to achieve the desired level of airflow distribution at HVAC exit. The present paper describes the design methodology of automotive HVAC mechanism system.

Adequate visibility through the vehicle windshield over the entire driving period is of paramount practical significance. Thin water film (fog) that forms on the windshield mainly during the winter season would reduce and disturb the driver’s visibility. This water film originates from condensing water vapor on inside surface of the windshield due to low outside temperatures. Primary source of this vapor is the passenger’s breath, which condenses on the windshield. Hot and dry air which impinges at certain velocity and angle relative to the windshield helps to remove the thin water film (defogging) and hence improves driver’s visibility. Hence a well-designed demisting device will help to eliminate this fog layer within very short span of time and brings an accepted level of visibility. An attempt is made here to design and develop a demisting device for a commercial vehicle with the help of numerical and analytical approach and later on validated with experimental results.

For an automotive exhaust system, noise level and back pressure are the most important parameters for passenger comfort and engine performance respectively. The sound quality perception of the existing silencer design was unacceptable, although the back pressure measured was below the target limit. To improve the existing design, few concepts were prepared by changing the internal elements of silencer only. The design constraints were the silencer shell dimensions, volume of silencer, inlet pipe and outlet tailpipe positions, which had to be kept same as that of the existing base design. The sound quality signal replaying and synthesizing was performed to define the desired sound quality. The numerical simulation involves 3D computational fluid dynamics (CFD) with appropriate boundary condition having less numerical diffusions to predict the back pressure. The various silencer concepts developed with this preliminary analysis, was then experimentally verified with the numerical data.

With the growing demand in passenger comfort and enhanced safety and high competitiveness in the automotive segment, automotive manufacturers are keen to launch the product flawlessly within short period of time. In that regard one of the areas related to safety of passengers which is windshield deicing, requires lot of attention and to be developed and certified well before the product launch. Computational fluid dynamics (CFD) helps in this regard to come up quickly with a feasible design solution. But with the conventional method of doing deicing requires lot of time and high cell count. Hence there is a requirement of developing a methodology which will shorten the simulation time and thus leading to shorter development time. One such development took place is in the multiphase models in CFD. The present study focuses in introducing a novel methodology for predicting the transient deicing pattern in an automotive windshield.

As the global warming due to carbon footprint is very alarming, vehicle emissions are getting stringent day by day. In such situation vehicle hybridization or fully electric vehicles are of obvious choices. However in any of the cases the battery cooling is a big concern area. As the heat produced by the battery need to be dissipated in the long run, it is of utmost need to develop and understand the battery cooling system. Present paper describes the experimental investigation of a battery cooling circuit. A complete bench comprising of both primary and secondary circuit is used for the testing. The primary circuit has a cooling unit with TXV, condenser and electric compressor run by high voltage. The secondary circuit consists of a chiller (integrated with TXV) unit responsible for battery cooling. The whole circuit typically resembles with one of dual air conditioning unit and uses one of known refrigerant used in vehicle AC system.

As the current market trend is emerging towards the compactness, better comfort and less emission, it is quite important that factors contributing to these aspects should be kept under control and maintained within the desired range. Heating ventilation and air conditioning (HVAC) noise is one such factor which significantly contributes in occupants’ acoustic comfort. It creates discomfort to the occupants while HVAC is in operation and eventually lead to fatigue. In a HVAC, there are several different types and sources of noise which cumulatively impacts the overall noise level. However, few of them are quite prominent and has maximum impacts on overall noise. It is very important to identify and measure these sources in order to take appropriate countermeasure to mask or eliminate them. In order to identify and measure the noise sources, various methods are used.

Vehicles wind shield are designed to provide a clear visibility in winter as its one of the most important requirement for the comfortable and safe journey. In extreme winters, wind shield of vehicle is covered with layer of ice and if frosted happened, results in reduces the visibility distance. To increase the visibility and providing the comfort to driving the vehicle, heater is used in vehicle as an integrated part of vehicle HVAC System. When the blower air passes through heater, air temperature gets increased. When the hot air is injected through grill at designed angle of injection and at selected air velocity on wind shield surface, ice on wind shield melting due to convection heat transfer phenomenon and thus achieved a clear windshield glass and clear visibility at driver and at co-driver area.

As HVAC noise is becoming one of the key factors to end users in terms of enhanced comfort, it is important to understand and evaluate various noise sources of HVAC in details. With detailed understanding of various sources, it becomes easier to take appropriate countermeasures in design and subsequently eliminate. There are many methods available in industry to investigate the noise sources in details however those options are expensive and time consuming and require deep understanding of the acoustic. Acoustical duct methods are one such method which proves to be very much helpful in identifying the noise sources from different aggregates like kinematics mechanism, door/damper, servomotors, heat exchangers etc. These sources are typically defined minor noise sources. The present paper describes the detailed investigation of those minor noise sources through the use of acoustical duct method. An existing HVAC from passenger car was considered for this study.

The aim of this paper is to optimize flow distribution on various ports of the ventilation unit. To improve the passenger comfort, ventilation unit need to be redesigned to get the uniform distribution in all ducts. There were challenges for the design modification on the unit to meet the distribution. The major challenge was to meet the distribution on the duct outlet without doing any design changes on the ducts. Hence the adapter which is the intermediate part between the blower and duct assembly is modified and simulation is done on the various design changes by changing the design of the adaptor part. CFD analysis is carried out on the ventilation unit with iterative design changes and achieved the target airflow and distribution. The analysis has been carried out on STAR CCM+ software.

For an efficient automotive AC system it is very essential to ensure uninterrupted and consistent airflow and temperature at the vent exit to help achieve the comfortable cabin space. This certainly requires temperature sensor to position at lowest possible temperature on heat exchanger and uniform flow distribution over it. However the uneven distribution of airflow on evaporator entry face leads to lowest temperature and sometimes goes undetected. This causes the condensate to get freezed and then frosting occurs at the core surface. Eventually a substantial portion of evaporator face gets choked and gradually airflow reduces and evaporator exit air temperature shoots up. Hence it is very important to prevent the frosting on evaporator core so to have uninterrupted airflow and adequate cooling in the passenger compartment. The present paper investigates the reasons for frosting occurring in one of the hatchback vehicle in bench test.

Maintaining thermal comfort is one of the key areas in vehicle HVAC design wherein airflow distribution inside the cabin is one of the important elements in deciding comfort sensation. However, the energy consumption of air conditioning system needs to stay within the efficient boundaries to efficiently cool down the passenger cabin otherwise the vehicle energy consumption may get worsened to a great extent. One approach to optimize this process is by using numerical methods while developing climate systems. The present paper focuses on the numerical study of cabin aiming and cabin cool-down of a passenger car by using computational fluid dynamics (CFD). The main goal is to investigate the cabin aiming with a view to figure out the minimum average velocity over the passengers at all vent positions. Cabin aiming ensures substantial amount of airflow reaches to the passengers as well as every corners of the cabin across the wide climatic range.

In the present study a numerical investigation is performed by using computational fluid dynamics (CFD) aiming to figure out and maximize the separation efficiency of an oil separator by changing the various design parameters. A typical automotive swash plate type compressor is chosen for this numerical investigation. Basically oil separation becomes very important where oil return is quite problematic due to the multiple constraints in piping layout design. Efficient oil separation makes the compressor lubrication easy and prevents from seizing during running. It also enhances the heat transfer from heat exchanger by reducing or separating oil from the refrigerant flowing in the air conditioning (AC) circuit. A computational method is proposed to analyze an oil separator fitted in a swash plate compressor. Eulerian multiphase model is employed to simulate the oil and refrigerant mixture model.

Indian Railways, often described as the “transport lifeline of the nation”, is the fourth largest railway network in the world, from suburbs to urban transit, the Indian rail network covers the length and breadth of the country. To make the journeys easier and memorable it is very much important to provide adequate comfort and easy access to every facilitates. For better comfort inside the coach as well as in the drivers’ cabin, air-conditioning system has to be quite effective and energy efficient. While it is too expensive to go with prototypes at the initial stage, numerical simulation comes very handy in helping and optimizing the unit and come out with viable design concept within very short time. The present study provides a methodology for the numerical simulation of a drivers’ cabin AC to determine the volumetric airflow rate. The unit is designed for the drivers’ cabin and it is mounted on roof.

Automotive heating ventilating and air conditioning (HVAC) noise is a very big concern for original equipment manufacturers (OEM) and suppliers. It turns out to be more challenging as the demand for acoustic comfort is increasing day by day. Many times an existing HVAC with some minor changes (mostly the vehicle fitment points) is proposed for face-lift vehicle but the performance expectation is far beyond the existing one due to market demand. One of the critical requirements is enhanced sound quality. To achieve that either experimental testing or numerical simulation is adopted. In either of these cases, it ends up with high number of experiments or increased simulation cost due to aero-acoustic simulation. Hence a combined approach is followed in order to investigate and improve the noise sources of an existing HVAC. The present paper describes this approach in details by doing numerical flow simulation followed by experimental investigation.