Browse Topic: Passenger compartments

Items (227)
Location of Crew and Passenger Oxygen Masks, Portable Oxygen System, and Protective Breathing EquipmentARP6390 (Current)8/10/2021
Various emergency situations may require the dispensing of oxygen to all occupants of aircraft during flight. During an emergency event, depending on the aircraft operational flight capability, all cabin occupants must be serviced by a mask presentation system connected to an operational oxygen source. Several regulations specify the functional characteristics and requirements of the oxygen systems for aircraft in support of different missions. These should be referred to for the exact functional performance requirements. It is not the intent of this document to ensure conformance with these regulations, but only to recommend general concepts for the location of the oxygen masks and oxygen system outlets for proper accessibility by the aircraft occupants, whether cabin occupants or crew members. Different requirements may apply when the mission of the pressurized aircraft or the operational altitude of the aircraft is not in excess of FL250. When the aircraft is operating above FL100, oxygen masks, either distributed to each cabin occupant or stowed and readily accessible, must be available in the event of a pressurization failure. Oxygen masks must also be connected to an operational source, available and within easy reach of each seated flight deck crew member and observer. For unpressurized aircraft, during flight operations above FL125, oxygen masks connected to an operational oxygen source must be available to all occupants. This document defines the accessibility requirements that should be considered in the placement of oxygen masks for presentation to the user and the connections for such oxygen masks to the operational oxygen systems. This is of interest when designing the interior of the aircraft, placing the seats in relationship to such outlets and mask connections, or placing oxygen mask outlets in relation to the seats. The accessibility requirements contained in this document are applicable to installation and arrangement of such equipment in different locations in the aircraft as shown on typical examples of installation areas as shown in Figures 3 through 15. Furthermore, this document does not discuss operational needs with respect to oxygen supply duration, nor the detail design of portable oxygen system or protective breathing equipment. Please refer to other SAE documents for such information. Portable Oxygen System and Protective Breathing Equipment are to be installed to meet the requirements of 25.1447(c) and 25.1439. Also, if portable oxygen equipment is installed, they need to meet the requirements of 14 CFR Part 25, Section 25.1443(d)& (e).
A-10 Aircraft Oxygen Equipment Committee
This document provides information applicable to the design and development of portable and aircraft mounted cabin air contaminant sensors. This AIR complements any future portable or aircraft-mounted cabin air sensor standards.
AC-9M Cabin Air Measurement Committee
Heavy commercial vehicles play an important role in creating the trade and economic balance of countries. Also, the durability and safety of heavy commercial vehicles come to the fore. Heavy commercial vehicles consist of two parts. These are the chassis area with the equipment that allows the vehicle to move and the cabin section where the driver is located. The cabin area is the most important area that ensures the highest level of driver safety. Considering that the production of trucks is increasing day by day, it is inevitable for companies to increase their R&D activities in the field of cabin and cabin suspension systems for much safer, durable, and comfortable trucks. This study aims to determine the safe torque value of the fasteners and their assembly sequence of the Cab Suspension Console, which is one of the most important connection parts in a truck and which can cause a fatal accident by breaking. In this study, the safe torque value of the fasteners of the cabin suspension console has been determined as 180 ± 15 Nm/180 ± 10 Grad for the outer fasteners and 225 ± 18 Nm/180 ± 10 Grad for the inner fasteners. In addition, two different assembly sequences are determined and permanent strains on the part are measured. At the end of the assembly test, permanent strains on the part and other factors affecting the strain are simulated. According to the results obtained, the assembly sequence with a low permanent strain value is chosen and commissioned in production.
Yildirim, BariscanÖztürk, Dogan
Investigate Partial Cabin Air Recirculation Strategy to Improve HVAC System’s Heating Performance Using 1D Simulation2020-01-01594/14/2020
In cold weather conditions, cabin heating performance is critical for retaining the thermal comfort. Heat is absorbed from the engine by circulating coolant through the engine water jacket and same will be rejected by the heater core. A variable speed blower is used to transfer heat from the heater core to the passenger compartment through floor ducts. The time taken to achieve comfortable cabin temperature determines the performance and capacity of heating ventilating and air conditioning (HVAC) system. In current automotive field, the engine options are provided to customers to meet their needs on the same vehicle platforms. Hence few engine variants cannot warm the cabin up to customer satisfaction. To improve the existing warm up performance of system, Positive thermal coefficient heater (PTC), electric coolant PTC heater, auxiliary pump etc. can be used which increases the overall cost of the vehicle. During warmup, HVAC system operates in 100% fresh mode. In this study, Partial cabin recirculation is investigated to understand the effect on the cabin warmup. In order to demonstrate this phenomenon, a one dimensional (1D) modelling approach is used for simulation and predicted the performance of different percentage of partial cabin air recirculation. Baseline correlation simulation is done with vehicle test data to reproduce the same test conditions in 1D software. Model output parameters such as floor duct outlet air temperature, Cabin warmup temperature are correlated at 0% partial recirculation in other words 100% fresh mode. By increasing the partial recirculation at each simulation run, increase in the floor duct outlet air temperatures is observed and witnessed through 1D model. This strategy can be applied to upcoming vehicle to improve the cabin warmup performance without any additional cost.
Belsare, SaurabhDanapalan, PrakashbabujiSambandan, SaravananGovindarajalu, Murali
Determination of Vehicle Interior Noise due to Electric Motor2019-01-14576/5/2019
This paper introduces an approach that uses a statistical energy analysis (SEA) method for prediction of noise in the vehicle cabin from an electric motor sound source placed in the engine compartment. The study integrates three different physics, namely, electromagnetics, harmonics, and acoustics. A 2004 Prius permanent magnet synchronous motor with an interior permanent magnet was used for performing the integrated CAE analysis, as the motor’s design details were readily available. The Maxwell forces on the stator teeth were first calculated by an electromagnetic software package. These forces were then mapped into a finite element model of the motor stator to predict the velocity profiles on the stator frame. Velocity profiles were considered as boundary conditions to calculate sound pressure levels and the equivalent radiated sound power level in the acoustic environment. The calculated sound power was used as an input sound source to perform SEA simulation to determine sound pressure level at the driver’s right ear in the passenger compartment. A sensitivity analysis of the motor design was performed on the sound power level generation and the sound noise level at the driver’s right ear in the passenger component. It was found that the air gap of the motor created significant effects on the radiated sound power.
Joshi, SanketCherng, John G.Salvekar, PinakRaveendra, Ravi
Development of Impact Force 1D Model for Powertrain Component2019-01-15496/5/2019
Electromagnetic valves excellent in sealing properties and resistant to sliding are often used in powertrain equipment installed in gasoline- or diesel-engine vehicles. An electromagnetic valve has the function of moving internal valve members by means of electromagnetic force generated by the application of a voltage and thereby changing the flow path. When an electromagnetic valve operates, however, the valve members impact with one another, emitting impact noise caused by it. With the requirement for low noise in electromagnetic valves having become stricter recently from the viewpoint of comfort in the passenger compartment, predicting the noise is needed at the design stage. With this background, this paper describes the development of a 1D model of impact force that will enable the noise and the product performance to be examined simultaneously for a GDI (gasoline direct injection) high pressure pump. In contrast to the conventional model in which a movable member is taken as a mass point with a spring and a damper placed at the impact section, this paper proposes a technique in which a spring-mass model with plural mass points is defined a basis on an eigenvalue of the movable member, verifying both models using measurement. In comparison with the conventional model, the proposed model can more exactly calculate the eigenvalues each of the three impact states in the opening operation of an electromagnetic valve. This allows one to improve that the accuracy in calculating the time characteristics of the force. This paper, in addition, gives cases of use of the developed model in studying the reduction of the force. Reducing the stiffness of the member exposed to impact force enabled the reduction in the high-frequency components of the force to be calculated with high precision, and the accompanying reduction in impact noise was confirmed on the actual machine.
Yoshimaru, YumaKondo, MakotoOmuro, YukieInaba, Masashi
Towards a Quiet Vehicle Cabin Through Digitalization of HVAC Systems and Subsystems Aeroacoustics Testing and Design2019-01-14766/5/2019
With the rise of electric autonomous vehicles, it has become clear that the cabin of tomorrow will drastically evolve to both improve ride experience and reduce energy consumption. In addition, autonomy will change the transportation paradigm, leading to a reinvention of the cabin seating layout which will offer the opportunity to climate systems team to design quiet and even more energy efficient systems. Consequently, Heat and Ventilation Air Conditioning (HVAC) systems designers have to deliver products which perform acoustically better than before, but often with less development time. To success under such constraints, designers need access to methods providing both assessment of the system (or subsystems) acoustic performance, and identification of where the designs need to be improved to reduce noise levels. Such methods are often needed before a physical prototype is requested, and thus can only be achieved in a timely manner through digital testing. Previous studies have demonstrated the ability of a CFD/CAA approach based on the Lattice Boltzmann Method (LBM) to predict HVAC system noise including real and complex ducts, registers, mixing unit and blower geometries. This LBM low dissipative numerical approach has indeed been shown to accurately capture turbulent and convective mechanisms and to propagate acoustic waves in ducted systems and in free-field. Combined with a noise source identification strategy, these methods provide the ability to visualize the noise sources inside the system, as well as to identify and rank noise-generating design features - a unique design methodology not available with physical testing. In this paper, such an approach is presented based on two HVAC systems layout, targeting two different vehicles. To answer the need for systems and subsystems predictions, simulation results are correlated to experiment for configurations with blower alone, blower + air intake, and for full HVAC system (blower + air intake + mixing unit). Finally, an in-depth analysis of the flow noise sources contributions to a microphone location is performed, and countermeasures are discussed.
Vidal, VincentMann, AdrienVerriere, JonasKim, MinsukAilloud, FabriceHenner, ManuelCheriaux, Olivier
CAE Based Head Form Impact Simulations for Development of Vehicle Interiors2019-26-02371/9/2019
The interior components of a passenger vehicle are designed to provide comfort and safety to its occupants. In the event of accident, vehicle interiors are primary source of injuries when occupants interact with them. Vehicle interiors consists of Instrument panel (IP), center console, seats and controls in front of seating position etc. Severity of the injuries depends on the energy dissipating characteristics, profiles, projections of different interior components. These are assessed by ECE R21 and IS12553 head form impact tests. To evaluate the Head form impact performance on Interior components, Computer Aided Engineering (CAE) simulations are extensively used during the vehicle development. In order to predict failure of plastic components and snap joints which might lead to expose sharp edges, it is critical to model plastic material and snap joint. Vehicle interiors are certified for head form impact requirements based on physical testing where dashboard samples from productions tools are used. At this stage of development, if any failure occurs then changes in interior design becomes very expensive and time consuming. To avoid this situation, CAE based failure predictions and injury performance evaluations are done during initial design phase of product development when changes are easily implemented without time and cost penalties. This paper describes the development of vehicle interior using CAE based head form impact simulations and predicting the failures like sharp edges exposure, structural integrity or joint failures. For accurate prediction of these failures in CAE based vehicle interior development, plastic material characterization and snap joint failure characterization are done.
Suryawanshi, YuvrajJoshi, KedarLambate, SachinJadhav, Vilas
Power Dissipation Optimization for Solid State Power Control Modules in the Aircraft Secondary Power Distribution System2018-01-193010/30/2018
In the last two decades, an aerospace industry trend in the secondary power distribution concept has been dominated by power electronics technology which includes power converters and Power Control Modules based on Solid State Power Control (SSPC) switching elements. These Power Control Modules, grouped around microprocessor based controllers and combined in a single electronic chassis, have become a backbone of electrical power distribution systems on all major commercial and military transport aircraft. Due to the resistive properties of the semiconductor-based SSPC devices, whose behaviors can be described as nonlinear functions of ambient operating temperature, power distribution system integration with SSPCs is challenged and heavily affected by operating temperatures and power dissipation limits. Although aircraft compartments where Power Control Modules are located are considered temperature and pressure controlled, high ambient operating temperatures are possible and expected. For that reason, Power Control Modules with multiple SSPC channels, at room ambient operating temperature, cannot utilize maximum power capacity, which means that a certain number of power control channels cannot be used for power distribution. As a result of that, to accommodate power dissipation potential growth over extended ambient operating temperature range, additional hardware has to be used. With the emergence of more electric aircraft, where a significant number of AC and DC type aircraft electrical loads have been connected to Power Control Modules, total power dissipation limitation with additional hardware has been creating significant impact on total equipment weight and cost. In an attempt to increase power density of the Power Control Modules and to mitigate the risk of permanent damage caused by excessive power dissipation at high ambient operating temperatures, this article presents a unique systems integration concept based on power management and electrical load shed as a function of critical ambient operating temperatures. The presented concept is scalable and can be implemented with no effect on aircraft performances and critical system functions.
Novakovic, NenoManojlovic, Milorad
Evaluation Method of Thermal Sensation and Comfort for Air Conditioning Performance Reduction2018-01-07754/3/2018
As a method of maintaining thermal sensation and comfort inside a passenger compartment, not only a conventional HVAC system but also a combination of a HVAC system and other devices such as seat heaters, a steering wheel heater, ventilation seats are increasing. This research developed a method to evaluate thermal sensation of a human body when using these various thermal control devices. This method can evaluate the heat balance of the human body by calculating the amount of heat exchange between a human body and the external environment, and it takes into consideration the influence of heat exchange by heat conduction with seats or a steering wheel. The human thermal model is made by dividing a human body into various segments, and it is the model that considers heat transport by blood flow for each segment. As a result of a heat balance of a human body, it is possible to derive the standard environmental temperature which is named the local-body standard new effective temperature (local SET*) for each part of a human body. Local thermal sensation is defined by a model equation that takes into consideration transient changes of a heat balance and an influence of heat storage by a whole body. Therefore, it is possible to evaluate thermal comfort of occupants in a vehicle cabin in transient and non-uniform situation. The authors conducted the experiment using actual vehicles and evaluated how much thermal sensation changes when an air conditioning system is different, using this evaluation method. Energy measurements for maintaining vehicle cabin environment and thermal sensation in the vehicle cabin were simultaneously carried out and the results of thermal sensation evaluation were shown.
ITO, YusukeSakoi, TomonoriMiyamoto, Takeshi
In recent years, start-stop systems have been implemented by many OEMs for improvement of fuel economy. When the engine stops, the occupant comfort typically deteriorates. Hence, the climate and fuel economy engineers are struggling to combine the passenger comfort and fuel economy. Especially in a vehicle cabin where the thermal environment becomes unsteady and highly non-uniform due to a start-stop. It is difficult to adapt any comfort evaluation index that have already been well established for a stationary/uniform space in building type environment in comparison to a vehicle cabin interior. The existing standard of ISO-14505-2 does not consider this for vehicle cabin interior condition. Hence, the authors have developed the occupant’s comfort prediction method under highly non-uniform condition and unsteady conditions and have established a new methodology [1].
Morishita, MasahiroUchida, ToshiyaMathur, Gursaran D.Kato, TakenaoMatsunaga, Kazuhiko
Studies on Impact Performance of Gradient Lattice Structure Applied to Crash Box2018-01-01194/3/2018
The conventional crash box with thin-walled column conceals some limitations on pedestrian protection and lightweight. The metallic NPR metamaterials designed in this study are based on re-entrant lattice structures. Re-entrant structures are known to be one main class of axenic structures that display negative Poisson’s ratio (NPR), which can be manufactured by 3D printing technology. This kind of metamaterial has good designability and can be used as the filling structure of the crash box to improve the crashworthiness of the car. This paper starts from the relations between geometric parameters of the metamaterial. Considering the deformation characteristics of the crash box, the structure were designed into some gradient types. The mechanical properties of different gradient structures under the same impact conditions were compared to find the proper gradient structures. Based on the studies, the gradient lattice structure is applied to the automobile crash box. We made some simulation by the finite element software LS-DYNA of vehicle head-on collision. We compared the crashworthiness of the cars which have different crash boxes. The accelerations of some key points in the crew compartment were measured. Also, we compared the energy absorption efficiency of the boxes. We came to the conclusion that the gradient lattice structure can efficiently improve the structural crashworthiness criteria of the thin-walled column and also achieve better pedestrian protection of the vehicle structure. Because the lattice structure has good impact performance, some other vehicle structures which need to have a good impact behavior can also be replaced by it .
Wu, XianZhang, ShuxianShao, Jianwang
The thermal comfort for the passenger inside the cabin is maintained by the HVAC system. To ensure a comfort for the 2nd row passengers in the cabin, it is very essential to design an efficient HVAC and rear console duct system which can deliver sufficient airflow with less pressure drop. The primary focus of the study is to assess existing airflow of the center console duct using CFD and propose improvement in its duct shape to meet the passenger comfort sitting in the rear seat. In this study, the vehicle cabin model, HVAC system and duct design was modeled using the design software UG. To analyze and estimate the behavior of the air flow of the system, a steady state simulation was performed using STAR CCM CFD software. The performance of the console duct system is judged by parameters like distribution of airflow, velocity at console duct outlet, pressure drop through the duct and the uniformity of the air flow at the passenger locations. Robust assessment methodology is followed for optimization of console duct to reduce the simulation iterations and arrive at the combination of appropriate design factors which influences the airflow, pressure drop within the duct and velocity at second row passenger locations within the short span of time. The impacts of each design factors on the output results have been analyzed extensively and best combination of design factors have been found out quickly through this methodology. Robust assessment methodology significantly aids in reducing the CFD simulation iterations by 40% and much faster than conventional optimization process. Vehicle testing was carried out for the existing and optimized console duct design to measure the improvement in airflow and velocity at passenger locations. There is a good correlation agreement between simulation and test results for the optimized design within the error of 10%. This methodology is very useful in reducing the number of prototypes, minimize the testing cost and reduce the simulation iterations during design and development stages of the program.
Vasanth, B.Khan, MohsinS, Sathish KumarGarikipati, NagababuNARAYANA, SathyaGovindarajalu, Murali
This document is a tool for the certifying authority, cockpit designers, instrument suppliers, lighting suppliers, and component suppliers. It is an aid to understanding and meeting relavant regulatory requirements, particularly those relating to pilot compartment view {CFR 25.773(a)(2)} and instrument lights {25.1381(a)(2)} for glare arising from visible eletromagnetic radiation.
A-20A Crew Station Lighting Committee
Exploitation Strategies of Cabin and Galley Thermal Dynamics2017-01-20379/19/2017
The thermal inertia of aircraft cabins and galleys is significant for commercial aircraft. The aircraft cabin is controlled by the Environment Control System (ECS) to reach, among other targets, a prescribed temperature. By allowing a temperature band of ± 2 K instead of a fixed temperature, it is possible to use this thermal dynamic of the cabin as energy storage. This storage can then be used to reduce electrical peak power, increase efficiency of the ECS, reduce thermal cooling peak power, or reduce engine offtake if it is costly or not sufficiently available. In the same way, also the aircraft galleys can be exploited. Since ECS and galleys are among the largest consumers of electrical power or bleed air, there is a large potential on improving energy efficiency or reducing system mass to reduce fuel consumption of aircraft. This paper investigates different exploitation strategies of cabin and galley dynamics using modelling and simulation. Modelica models of the thermal and the electrical system are used to assess and compare these different strategies. Potential impacts on passenger comfort are discussed. Additionally, the gained performance is compared to more conventional storage elements like electrical batteries. Finally, the potential of fuel reduction will be quantified using a reference aircraft model and the optimal strategy is selected.
Schlabe, DanielZimmer, DirkPollok, Alexander
Error Microphone Placement Optimization for Concurrent MIMO Feedback ANC Systems2017-01-18286/5/2017
The use of active noise control (ANC) systems in automotive applications has been common practice for well over a decade. Many of these systems utilize at least one error microphone that is placed inside the vehicle cabin and provides feedback to the algorithm in order to assess the effectiveness of the anti-noise signal as it attempts to cancel primary noise. Prior work pertaining to optimal error microphone placement has not provided any objective metrics that correlate to the noise reduction experienced inside the vehicle cabin. The goal of this paper is to establish empirically-based metrics which can be used to quantitatively describe why one microphone position in the vehicle is superior or less favorable when compared to another. These metrics are used when considering concurrent multiple-input multiple-output (MIMO) ANC systems that utilize the same error microphones but are trying to attenuate both broadband and narrowband noise. Empirical correlation of these metrics with respect to the noise reduction achieved is shown with in-vehicle acoustic measurements. Cross-correlation effects were observed between error microphones in different quadrants of the vehicle; however, an average of the metrics and the noise reduction across all quadrants of the vehicle showed a meaningful correlation that can be used as the basis for further development of this methodology.
Christian, JonathanStafford, Dylan
A Desktop Procedure for Measuring the Transmission Loss of Automotive Door Seals2017-01-17606/5/2017
Due the increasing concern with the acoustic environment within automotive vehicles, there is an interest in measuring the acoustical properties of automotive door seals. These systems play an important role in blocking external noise sources, such as aerodynamic noise and tire noise, from entering the passenger compartment. Thus, it is important to be able to conveniently measure their acoustic performance. Previous methods of measuring the ability of seals to block sound required the use of either a reverberation chamber, or a wind tunnel with a special purpose chamber attached to it. That is, these methods required the use of large and expensive facilities. A simpler and more economical desktop procedure is thus needed to allow easy and fast acoustic measurement of automotive door seals. In the present work, a desktop, four-microphone, square cross-section standing wave tube was modified by the addition of a new sample holder to make it possible to measure the transmission loss of door seals under various states of compression. In this new procedure, the sample is clamped between a sliding piston and one wall of the standing wave tube. Since the clamp partially blocks the channel, thus impacting the measured transmission loss, a correction is necessary to determine the transmission loss of the seal by itself. Therefore, an initial set of measurements was performed to identify the correction factor required to adjust the measured transmission loss of the clamp plus seal to eliminate the contribution of the clamp itself. Once the accuracy of the correction procedure was verified, a number of typical door seals were tested at various degrees of compression. The transmission losses of the seals were generally in excess of 30 dB, and the transmission loss was found to increase significantly as the seals were compressed. The latter point, in particular, indicates that careful design of the seal mounting arrangements in the vehicle is crucial to ensuring their optimal performance.
Thor, WeiminBolton, J. Stuart
Audio Synthesis and Sound Quality of Automotive Air-Conditioning Systems2017-01-18876/5/2017
While electric and hybrid vehicles are becoming increasingly common, the issue of engine noise is becoming less important, because it does not dominate the overall noise perceived in the passenger compartment in such vehicles anymore. However, at the same time, other sound sources such as air conditioning, start to emerge, which can also cause annoyance. The CEVAS project, involving VALEO, CETIM, University of Technology of Compiègne, ESI GROUP and GENESIS, deals with the acoustic simulation and perception of automotive air-conditioning (HVAC) and electric battery cooling (BTM) systems. While the other partners focused their work on the aeroacoustic characterization, modeling and simulation, GENESIS’ part in the project is dedicated to HVAC sound synthesis and perception. In order to do the synthesis of the acoustic spectra provided by the partners of the project, an additive model was used. Its ability to reliably reproduce sound recordings was addressed through a listening experiment, which also helped in defining the necessary resolution of the input spectra in order to produce convincing sounds. Finally, various HVAC sounds, including different models, operating modes and airflow rates, were assessed by means of a psychoacoustic method involving two listening experiments: a verbalization task, and a semantic differential task. The results were statistically analyzed and a robust sound quality model based on loudness and tonality metrics was proposed.
Minard, AntoineLambourg, ChristopheBoussard, PatrickCheriaux, Olivier
Energy Consumption of Passenger Compartment Auxiliary Cooling System Based on Peltier Effect2017-01-01553/28/2017
The closed cabin temperature is anticipated to be cooled down when it is a bit hot inside the driving car. The traditional air-condition lowers the cabin temperature by frequently switching the status of the compressor, which increases the engine’s parasitic power and shortens the compressor’s service-life. The semiconductor auxiliary cooling system with the properties of no moving parts, high control precision and quick response has the potential to assist the on-board air-condition in modulating the cabin temperature with relative small ranges. Little temperature differences between the cabin and the outside environment means that the system energy consumption to ensure the occupant comfort is relatively low and the inefficiency could be made up by the renewable energy source. This research focuses on the influence of the vehicle speed and the ambient temperature over the cooling energy consumption considering occupant heat dissipation in order to maximize the system energy utilization. Firstly, the occupant heat dissipation model is established and the system refrigerating capacity is confirmed for occupant comfort. Secondly, the temperature and the heat flux density at both ends of the semiconductor are studied. Finally, the energy consumption regulations of the auxiliary cooling system are clarified for different vehicle speeds and ambient temperatures. The results show that the vehicle speed is a key factor affecting the supplied current, especially for the vehicle speed less than 40km/h. The system current variation is within 0.4A corresponding to the ambient temperature changes. The occupant heat dissipation changes the current range. The system energy utilization could be improved by controlling the supplied current in a relatively small range at various vehicle speeds and ambient temperatures.
Xu, YongbingTan, GangfengGuo, XuexunPing, Xianyao
Investigation of a Dual HVAC MAC System with Three Row Ducts Using 1D Modeling2017-01-01643/28/2017
In an automotive air-conditioning (AC) system, upfront prediction of the cabin cool down rate in the initial design stage will help in reducing the overall product development (PD) time. Vehicle having higher seating capacity will have higher thermal load and providing thermal comfort to all passengers uniformly is a challenging task for the automotive HVAC (Heating Ventilation and Air conditioning) industry. Dual HVAC unit is generally used to provide uniform cooling to a large cabin volume. One dimensional (1D) simulation is being extensively used to predict the HVAC performance during the initial stage of PD. The refrigerant loop with components such as compressor, condenser, TXV and evaporator was modeled. The complicated vehicle cabin including the glazing surfaces and enclosures were modeled as a three row duct system using 1D tool AMESim®. The material type, density, specific heat capacity and thermal conductivity of the material were specified. The actual vehicle driving conditions as per test standard were used to validate the transient 1D HVAC performance simulations. The heat gain values of the panel ducts were adjusted to reduce the deviation from test. The simulated results for average cabin temperature and grill outlet temperature were compared against a surrogate vehicle test data. The detailed comparison of test data and simulation results were plotted and identified the simulation parameter which affects the correlation. Studies were carried out to understand the influence of thermal parameters on the performance of dual HVAC system and optimal values were arrived for the system under study.
Muthusamy, VenkatesanSathish Kumar, S.Sambandan, Saravanan
Robust 1D Modelling for Automotive HVAC Warmup Prediction Using DFSS Approach2017-01-01793/28/2017
In an automotive air-conditioning (AC) system, the heater system plays a major role during winter condition to provide passenger comforts as well as to clear windshield defogging and defrost. In order to meet the customer satisfaction the heater system shall be tested physically in severe cold conditions to meet the objective performance in wind tunnel and also subjective performance in cold weather regions by conducting on road trials. This performance test is conducted in later stage of the program development, since the prototype or tooled up parts will not be available at initial program stage. The significance of conducting the virtual simulation is to predict the performance of the HVAC (Heating ventilating air-conditioning) system at early design stage. In this paper the development of 1D (One dimensional) model with floor duct systems and vehicle cabin model is studied to predict the performance. Analysis is carried out using commercial 1D simulation tool KULI®. All the simulation parameter which affects the correlation process has been studied carefully by using DFSS (Design for six sigma) methodology. L18 orthogonal array developed to understand the influence of each simulation parameters. Data analysis is carried out from DFSS study output and identified the importance of each simulation parameters which is being adjusted for correlation. This methodology helps to predicts accurately for any change in the HVAC heater systems circuit components like heater core, heater core inlet coolant flows, heater core inlet coolant temperatures, heater core airflow etc. This study enhances to reduce the number of physical tests, prototypes and cost involved in it.
Sambandan, SaravananValencia, ManuelS, Sathish Kumar
Risks of Lightning to Automotive Occupants and Electrical/Electronic Systems2017-01-00613/28/2017
Lightning strikes on automobiles are usually rare, though they can be fatal to occupants and hazardous to electronic control systems. Vehicles’ metal bodies are normally considered to be an effective shield against lightning. Modern body designs, however, often have wide window openings, and plastic body parts have become popular. Lightning can enter the cabin of vehicles through their radio antennas. In the near future, automobiles may be integrated into the electric power grid, which will cause issues related to the smart grid and the vehicle-to-grid concept. Even today, electric vehicles (EVs) and plug-in hybrid vehicles (PHEVs) are charged at home or in parking lots. Such automobiles are no longer isolated from the power grid and thus are subject to electric surges caused by lightning strikes on the power grid. A charging system connected to an EV or PHEV should absorb the surge, but powerful lightning strikes can overwhelm the surge protection and intrude into the electric and electronic (E/E) systems of the vehicles, as often happens with household electrical equipment. This paper discusses the increasing risks of lightning to automotive occupants and E/E systems. To demonstrate the risk to vehicle systems, artificial lightning was generated by a 3 MV-impulse voltage source and supplied to a test vehicle. Arcing at the vehicle’s metal joints was then observed; the electronic system of the instrument panel was destroyed in the experiment. The induced surge voltage and lightning current in the metal body were both measured to determine the impact on the vehicle’s electronic systems. In order to develop a theoretical model for vehicle lightning, a NiCr metal box was also examined under artificial lightning conditions. In these experiments, neither the vehicle’s metal body nor the NiCr box shielded the lightning well. During lightning strikes, significant voltage differences were observed in the metals, and the vehicle body did not work as a common ground. The voltage difference also suggested the generation of an electromagnetic field in the vehicle cabin that can be harmful to vehicle systems.
Alkhteeb, Sultan A.MOho, ShigeruNagashima, YukiNishimura, SeisukeShimizu, Hiroyuki
Thermal Storage System for Electric Vehicle Cabin Heating - Component and System Analysis2016-01-02444/5/2016
Cabin heating of current electric vehicle (EV) designs is typically provided using electrical energy from the traction battery, since waste heat is not available from an engine as in the case of a conventional automobile. In very cold climatic conditions, the power required for space heating of an EV can be of a similar magnitude to that required for propulsion of the vehicle. As a result, its driving range can be reduced very significantly during the winter season, which limits consumer acceptance of EVs and results in increased battery costs to achieve a minimum range while ensuring comfort to the EV driver. To minimize the range penalty associated with EV cabin heating, a novel climate control system that includes thermal energy storage from an advanced phase change material (PCM) has been designed for use in EVs and plug-in hybrid electric vehicles (PHEVs). The present paper focuses on the modeling and analysis of this electrical PCM-Assisted Thermal Heating System (ePATHS) and is a companion to the paper “Design and Testing of a Thermal Storage System for Electric Vehicle Cabin Heating.” A detailed heat transfer model was developed to simulate the PCM heat exchanger that is at the heart of the ePATHS and was subsequently used to analyze and optimize its design. The results from this analysis were integrated into a MATLAB Simulink system model to simulate the fluid flow, pressure drop and heat transfer in all components of the ePATHS. The system model was then used to predict the performance of the climate control system in the vehicle and to evaluate control strategies needed to achieve the desired temperature control in the cabin. The analysis performed to design the ePATHS is described in detail and the system’s predicted performance in a vehicle HVAC system is presented.
LaClair, Tim J.Gao, ZhimingAbdelaziz, OmarWang, MingyuWolfe, EdwardCraig, Timothy
Solar Heat Load on the Vehicle Occupants2016-01-02464/5/2016
Vehicle occupants, unlike building occupants, are exposed to continuously varying, non-uniform solar heat load. Automotive manufacturers use photovoltaic cells based solar sensor to measure intensity and direction of the direct-beam solar radiation. Use of the time of the day and the position - latitude and longitude - of a vehicle is also common to calculate direction of the direct-beam solar radiation. Two angles - azimuth and elevation - are used to completely define the direction of solar radiation with respect to the vehicle coordinate system. Although the use of solar sensor is common in today’s vehicles, the solar heat load on the occupants, because of their exposure to the direct-beam solar radiation remains the area of in-car subjective evaluation and tuning. Since the solar rays travel in parallel paths, application of the ray tracing method to determine solar insolation of the vehicle occupants is possible. Calculating the solar exposure however requires the knowledge of geometry of the passenger compartment of a vehicle in addition to the direction of the direct-beam solar radiation. Geometry information includes 3D coordinates of the vehicle glasses and the passenger seating location. Planar surface approximation is used to represent both the glasses and the seats. Further the seat coordinates are shifted to obtain exposure of the occupants than the seats. Shifting of the seat coordinates is performed according to the thickness of chest and lap of an average adult. The solar exposure calculation also requires correction to the measured solar intensity. The correction is to account for attenuation of the solar radiation by the transmittance of the vehicle glasses. The solar heat load is then obtained by multiplying the occupant’s solar exposure area in m2 and the transmitted solar intensity in W/m2 for the given solar angles and vehicle geometry. The results of solar heat load so obtained are compared with the CFD Fluent data for a compact SUV.
Kakade, Rupesh SonuMer, Prashant
A Novel Approach to Predict HVAC Noise Using 1D Simulation2016-01-02494/5/2016
In recent years reducing the automobile HVAC (Heating Ventilation and automobile conditioning) noise inside the vehicle cabin is one of the main criterions for all OEMs to provide comfort level to the passengers. The primary function of the HVAC is to deliver more air to the cabin with less noise generation for various blower speeds. Designing the optimum HVAC with less noise is one of the major challenges for all automotive manufacturers and HVAC suppliers. During the design stage, physical parts are not available and hence the simulation technique helps to evaluate the noise level of HVAC. In this study, a computational 1D (one dimensional) analysis is carried out to compute the airflow noise originated from the HVAC unit and propagated to the passenger cabin. Modeling has been done using unigraphics and the analysis is carried out using the commercial 1D software GT suite. The inner volume of the 3D HVAC model comprising of blower fan, evaporator, heater, housing and dampers are extracted and discretized in to 1D model using the GT suite volume extraction technique. The inputs for the analysis are the airflow at HVAC Inlet, blower speed, fan performance characteristics and the pressure drop characteristics of evaporator, filter and heater core. Imposed mass flow rate method is used to predict the airflow noise generated by flow through the HVAC. The result predicted is the sound pressure level in dBA measured at 50 cm away from HVAC outlet in defrost and panel mode for different air flow rates covering a frequency range of 0Hz to 5000 Hz. Bench level test is done by placing the HVAC unit in the anechoic chamber with the different air flow rates and the sound pressure levels are measured using a microphone. Simulation results are compared with the bench test results and the error is within 7 %. The validated model can be used to assess the HVAC noise during early design stages of the program and design can be optimized based on the simulation results. The above 1D methodology has an edge compared to 3D analysis as the simulation is faster and the results are well correlated. This 1D model significantly aids in reducing the physical tests and time required to predict the noise level.
Vasanth, BalashunmuganathanSathish, KumarGovindarajalu, MuraliKhan, Mohsin
Reduction of Energy Used for Vehicle Interior Climate2016-01-02504/5/2016
In recent years fuel consumption of passenger vehicles has received increasing attention by customers, the automotive industry, regulatory agencies and academia. However, some areas which affect the fuel consumption have received relatively small interest. One of these areas is the total energy used for vehicle interior climate which can have a large effect on real-world fuel consumption. Realistic combinations of energy saving measures were evaluated regarding the total energy use for vehicle interior climate using a one dimensional (1D) simulation model. The 1D simulation model included sub models of the passenger compartment, the air-handling unit, the Air Conditioning (AC) system, engine and engine cooling system. A test cycle representative for real-world conditions was developed. The test cycle included tests in cold, intermediate and warm conditions and the results were weighted with the estimated use in each condition. In the investigated case the average electrical power was decreased with 50%, primarily through a new blower control unit. The mechanical compressor power was decreased with 45%, primarily through less engaged AC-system. In addition the energy flow into the passenger compartment, for cooling and heating, was decreased with almost 20%, largely through increased insulation of windows, shell, ducts, and decreased interior mass. All these savings were made without decreasing the potential of thermal comfort for the passengers. When the most beneficial energy saving measures have been implemented further reductions of energy use for the climate control system will become very challenging. To achieve additional energy reductions, with this type of system, the airflow has to be reduced or more energy must be recovered from the air. Many challenges with these measures can be expected.
Nielsen, FilipUddheim, ÅsaDalenbäck, Jan-Olof
Climate Control Load Reduction Strategies for Electric Drive Vehicles in Cold Weather2016-01-02624/5/2016
When operated, the cabin climate control system is the largest auxiliary load on a vehicle. This load has significant impact on fuel economy for conventional and hybrid vehicles, and it drastically reduces the driving range of all-electric vehicles (EVs). Heating is even more detrimental to EV range than cooling because no engine waste heat is available. Reducing the thermal loads on the vehicle climate control system will extend driving range and increase the market penetration of EVs. Researchers at the National Renewable Energy Laboratory have evaluated strategies for vehicle climate control load reduction with special attention toward grid-connected electric vehicles. Outdoor vehicle thermal testing and computational modeling were used to assess potential strategies for improved thermal management and to evaluate the effectiveness of thermal load reduction technologies. A human physiology model was also used to evaluate the impact on occupant thermal comfort. Experimental evaluations of zonal heating strategies demonstrated a 5.5% to 28.5% reduction in cabin heating energy over a 20-minute warm-up. Vehicle simulations over various drive cycles show a 6.9% to 18.7% improvement in EV range over baseline heating using the most promising zonal heating strategy investigated. A national-level analysis was conducted to determine the overall national impact. If all vehicles used the best zonal strategy, the range would be improved by 7.1% over the baseline heating range. This is a 33% reduction in the range penalty for heating.
Jeffers, Matthew A.Chaney, LarryRugh, John P.
Internal Pressure Characteristics when Evaluating Dynamic Door Blow Out Deflection2015-01-23276/15/2015
Wind noise is one of the most influential NVH attributes that impact customer sensation of vehicle interior quietness. Among many factors that influence wind noise performance, the amount of dynamic door deflection under the pressure load due to fast movement of a vehicle plays a key roll. Excessive deflection could potentially lead to loss of sealing contact, causing aspiration leakage, which creates an effectual path through which the exterior aerodynamically induced noise propagates into the vehicle cabin. The dynamic door deflection can be predicted using CFD and CAE approaches which, in addition to modeling the structure correctly, require a correct pressure loading composed of external and internal pressure distributions. The determination of external pressure distributions can be fulfilled fairly straightforward by using commercial CFD codes such as Fluent, Star CCM+, Powerflow and others. However, the capability of predicting the internal pressure due to high wind speed outside of a vehicle has not been developed. This work looks into the internal pressure characteristics associated with the dynamic loading setup that is required for analytical efforts. The work is based on the wind tunnel measurement data involving several vehicles. By comparing the measured internal pressure data, along with CAE results, the issues are summarized and a conservative internal pressure load value is recommended.
Hou, HangshengZhao, WeiHou, Jian
Vibro-Acoustic Properties of a Very Long Flax Fibers Reinforced Thermoset “Flaxpreg” Light Sandwich2015-01-23456/15/2015
The Flaxpreg is a green and light very long flax fibers thermoset reinforced sandwich, which can be effectively used as multi-position trunk loadfloor or structural floor in the passenger compartment of a vehicle. The prepreg FlaxTapes of about 120 g/m2 constituting the skins of the sandwich, are unidirectionally aligned flax fibers tapes, with acrylic resin here, easily manipulable without requiring any spinning or weaving step and thus without any negative out of plane crimping of the almost continuous flax fibers. Thanks to their very low 1.45 kg/dm3 density combined with an adaptive 0°/90°/0° orientation of the FlaxTapes (for each skin) depending on the loading boundary conditions, the resulting excellent mechanical properties allow a - 35% weight reduction compared to petro-sourced Glass mat/PUR sandwich solutions (like the Baypreg). The vibro-acoustic damping properties of these FlaxTape skins are remarkable with an almost 2 % Damping Loss Factor, whereas glass/resin or carbon/resin composites lie at around 0.15%. This study presents a comprehensive measurement and simulation correlation campaign of the vibro-acoustic properties of the Flaxpreg sandwich, namely its Damping Loss Factor and its airborne Transmission Loss with and without necessary noise treatments to ensure a good NVH comfort. Various simulation methods from the simplest models to the most complex ones will be compared to one another and to measurements: namely analytical sandwich models implemented in SEA softwares, Transfer Matrix Methods sandwich formulations as well as Finite Element/Boundary Element detailed or homogenized models including poroelastic materials…
Duval, ArnaudMarcel, ValérieDejaeger, LudovicLhuillier, FrancisKhalfallah, Moussa
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