Browse Topic: Passenger compartments
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
Passenger expectations for quiet and acoustically comfortable vehicle interiors have increased significantly, driven by advancements in electric vehicles and premium audio systems. Acoustic comfort affects perceived quality, communication ease, and overall driving experience. This paper presents a simulation-driven methodology to predict and optimize interior noise performance during the early design phase, focusing on high-frequency acoustic transfer functions and trim material absorption properties. Traditional NVH development relies heavily on physical testing, which is time-consuming and costly. Early-stage predictive tools are essential to evaluate acoustic performance before prototype availability. High-frequency noise (1kHz–12kHz) is particularly challenging due to complex reflections and absorption behavior. Acoustic trims play a critical role in shaping the cabin’s sound field, and their properties must be optimized to achieve desired sound quality. A novel simulation approach
The Audio system is an important part of the design of a vehicle cabin. In the vehicle development process, the audio system needs to be tuned for optimal acoustic performance. Traditionally, this process is performed physically on vehicles. In this paper, a methodology is developed to numerically simulate the acoustic performance of the audio system across the full audible frequency range. To provide validation of the method, the p/v acoustic transfer functions (ie., the sound pressure p at the passengers’ ears divided by the voltage inputs v) are measured for different speakers in a production vehicle. As the sound perceived by the passengers depends on both the source and the path, the method development is split into two parts: (a) characterization of parameters that describe the loudspeaker as a source and (b) representation of the vehicle cabin as a path. The speaker parameters are characterized from sound radiation data measured in a 2pi chamber. To represent the vehicle cabin
As already well-understood/enormous engineering practices, the inverter AC-side NVH phenomena/mechanisms/measures for motor-equipped vehicle, are already pretty clear. In addition to inverter AC side–induced NVH issues, DC ripple induced by PE switching leads to NVH issues manifesting on the capacitor, inductor, and conductor in terms of reverse piezoelectricity, electrostriction, magnetostriction, Laplace force, and so forth. These DC-side NVH issues are already literally analyzed by a couple of literatures, and mechanisms/measures are explored/applied to electric drive development. And yet, the phenomenon that a pulsating magnetic field inside a battery pack induced by DC current ripple off PE switching brings noise at switching frequency inside the vehicle cabin is newly captured/analyzed by our research, and that has been barely searched during the literature survey. This newly discovered phenomenon is the pivotal point in this paper. Although the noise features like the
Side crashes are generally hazardous because there is no room for large deformation to protect an occupant from the crash forces. A crucial point in side impacts is the rapid intrusion of the side structure into the passenger compartment which need sufficient space between occupants and door trim to enable a proper unfolding of the side airbag. This problem can be alleviated by using the rising air pressure inside the door as an additional input for crash sensing. With improvements in the crash sensor technology, pressure sensors that detect pressure changes in door cavities have been developed recently for vehicle crash safety applications. The crash pulses recorded by the acceleration based crash sensors usually exhibit high frequency and noisy responses. The data obtained from the pressure sensors exhibit lower frequency and less noisy responses. Due to its ability to discriminate crash severities and allow the restraint devices to deploy earlier, the pressure sensor technology has
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
In pursuit of a distinct sporty interior sound character, the present study explores an innovative strategy for designing intake systems in passenger vehicles. While most existing literature primarily emphasizes exhaust system tuning for enhancing vehicle sound quality, the current work shifts the focus toward the intake system’s critical role in shaping the perceived acoustic signature within the vehicle cabin. In this research work, target cascading and settings were derived through a combination of benchmark and structured subjective evaluation study and aligning with literature review. Quantitative targets for intake orifice noise was defined to achieve the desired sporty character inside cabin. Intake orifice targets were engineered based on signature and sound quality parameter required at cabin. Systems were designed by using advanced NVH techniques, Specific identified acoustic orders were enhanced in the intake system to reinforce the required signature in acceleration as well
This SAE Aerospace Standard (AS) provides design criteria for onboard stairways intended for use by passengers aboard multi-deck transport category airplanes. It is not intended for stairways designed for use only by crewmembers, supernumeries, or maintenance personnel. Additionally, this AS does not apply to fuselage mounted or external stairways used for boarding passengers, which are covered by ARP836.
Wind noise is one of the largest sources to interior noise of modern vehicles. This noise is encountered when driving on roads and freeways from medium speed and generates considerable fatigue for passengers on long journeys. Aero-acoustic noise is the result of turbulent and acoustic pressure fluctuations created within the flow. They are transmitted to the passenger compartment via the vibro-acoustic excitation of vehicle surfaces and underbody cavities. Generally, this is the dominant flow-induced source at low frequencies. The transmission mechanism through the vehicle floor and underbody is a complex phenomenon as the paths to the cavity can be both airborne and structure-borne. This study is focused on the simulation of the floor contribution to wind noise of two types of vehicles (SUV and Sports car), whose underbody structure are largely different. Aero-Vibro-acoustic simulations are performed to identify the transmission mechanism of the underbody wind noise and contribution
High-frequency whine noise in electric vehicles (EVs) is a significant issue that impacts customer perception and alters their overall view of the vehicle. This undesirable acoustic environment arises from the interaction between motor polar resonance and the resonance of the engine mount rubber. To address this challenge, the proposal introduces an innovative approach to predicting and tuning the frequency response by precisely adjusting the shape of rubber flaps, specifically their length and width. The approach includes the cumulation of two solutions: a precise adjustment of rubber flap dimensions and the integration of ML. The ML model is trained on historical data, derived from a mixture of physical testing conducted over the years and CAE simulations, to predict the effects of different flap dimensions on frequency response, providing a data-driven basis for optimization. This predictive capability is further enhanced by a Python program that automates the optimization of flap
Noise transmission through the vehicle dash panel plays a critical role in isolating passengers from noise sources within the motor bay of the vehicle. Grommets that contain electrical harness routing as well as HVAC lines are examples of dash panel pass-throughs that should be selected with care. Acoustic performance of these components is generally characterized in terms of measured quantities such as noise reduction (NR), sound transmission loss (STL), and insertion loss (IL). These measurements need to be carried out per SAE or ASTM standards in appropriate anechoic or reverberant chambers as this is important for consistency. This work explores an in-situ measurement of the grommet STL performance in the vehicle environment. It utilizes a repurposed vehicle with its cabin retrofitted to serve as an anechoic chamber and its frunk acting as a reverberant chamber. Results of this in-situ measurement are then compared to measurements following industry standards to discuss the
Airworthiness certification of aircraft requires an Airworthiness Security Process (AWSP) to ensure safe operation under potential unauthorized interactions, particularly in the context of growing cyber threats. Regulatory authorities mandate the consideration of Intentional Unauthorized Electronic Interactions (IUEI) in the development of aircraft, airborne software, and equipment. As the industry increasingly adopts Model-Based Systems Engineering (MBSE) to accelerate development, we aim to enhance this effort by focusing on security scope definitions – a critical step within the AWSP for security risk assessment that establishes the boundaries and extent of security measures. However, our findings indicate that, despite the increasing use of model-based tools in development, these security scope definitions often remain either document-based or, when modeled, are presented at overly abstract levels, both of which limit their utility. Furthermore, we found that these definitions
Increasing digitalization of the aircraft cabin, driven by the need for improved operational efficiency and an enhanced passenger experience, has led to the development of data-driven services. In order to implement these services, information from different systems is often required, which leads to a multi-system architecture. When designing a network that interconnects these systems, it is important to consider the heterogeneous device and supplier landscape as well as variations in the network architecture resulting from airline customization or cabin upgrades. The novel ARINC 853 Cabin Secure Media-Independent Messaging (CSMIM) standard addresses this challenge by specifying a communication protocol that relies on a data model to encode provided and consumed information. This paper presents an approach to integrate CSMIM-specific communication concepts into a Model-Based Systems Engineering (MBSE) framework using the Systems Modeling Language (SysML). This enables a streamlined
This ARP provides design and performance recommendations for emergency exits in the passenger cabin. This ARP does not apply to Crew Emergency Exits.
This SAE Aerospace Recommended Practice (ARP) establishes safety recommendations for lavatories in transport category airplanes.
This SAE Aerospace Recommended Practice (ARP) contains guidelines and recommendations for subsonic airplane air conditioning systems and components, including requirements, design philosophy, testing, and ambient conditions. The airplane air conditioning system comprises that arrangement of equipment, controls, and indicators that supply and distribute air to the occupied compartments for ventilation, pressurization, and temperature and moisture control. The principal features of the system are: a A supply of outside air with independent control valve(s). b A means for heating. c A means for cooling (air or vapor cycle units and heat exchangers). d A means for removing excess moisture from the air supply. e A ventilation subsystem. f A temperature control subsystem. g A pressure control subsystem. Other system components for treating cabin air, such as filtration and humidification, are included, as are the ancillary functions of equipment cooling and cargo compartment conditioning
This ARP provides the definition of terms commonly used in aircraft environmental control system (ECS) design and analysis. Many of the terms may be used as guidelines for establishing standard ECS nomenclature. Some general thermodynamic terms are included that are frequently used in ECS analysis, but this document is not meant to be an inclusive list of such terms.
From a Noise Vibration Harshness (NVH) perspective, electric vehicles represent a great opportunity since the noise of the combustion engine, dominant in many driving conditions, is no longer present. On the other hand, drivers accustomed to driving cars with a strong personality (for example typically sporty ones) may perceive "silence" as a lack of character. Our internal study, conducted with a jury of people, has in fact already shown that for half of customers silence should characterize (Battery Electric Vehicle - BEV) vehicle; but, at the same time, the other half of the jury expects feedback from the vehicle while driving. The silence inside the passenger compartment, from an NVH point of view, can therefore be compared to a blank sheet of paper, on which, if desired, sounds designed to satisfy the driving pleasure expected by the customer can be introduced. Starting from this scenario, the paper describes: the approach adopted to define how many and what are the levers to
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