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Browse AllThis SAE Aerospace Recommended Practice (ARP) discusses design philosophy, system and equipment requirements, environmental conditions, and design considerations for rotorcraft environmental control systems (ECS). The rotorcraft ECS comprises that arrangement of equipment, controls, and indicators which supply and distribute dehumidified conditioned air for ventilation, cooling and heating of the occupied compartments, and cooling of the avionics. The principal features of the system are: a A controlled fresh air supply b A means for cooling (air or vapor cycle units and heat exchangers) c A means for removing excess moisture from the air supply d A means for heating e A temperature control system f A conditioned air distribution system The ARP is applicable to both civil and military rotorcraft where an ECS is specified; however, certain requirements peculiar to military applications—such as nuclear, biological, and chemical (NBC) protection—are not covered. The integration of NBC
This SAE Aerospace Recommended Practice (ARP) defines recommended analysis and test procedures for qualification of pneumatically, electrically, manually, and hydraulically actuated air valves. They may be further defined as valves that function in response to externally applied forces or in response to variations in upstream and/or downstream duct air conditions in order to maintain a calibrated duct air condition (e.g., air flow, air pressure, air temperature, air pressure ratio, or air shutoff). Qualification testing performed on the airplane to verify compatibility of the valve function and stability as part of a complete system is outside the scope of this document. Refer to ARP1270 for design and certification requirements for cabin pressurization control system components. As this document is only a guide, it does not supersede or relieve any requirements contained in detailed Customer specifications.
This specification covers a corrosion-resistant steel in the form of investment castings homogenized and solution and precipitation heat treated to 180 ksi (1241 MPa) tensile strength.
In recent times, a standard driving cycle is an excellent way to measure the electric range of EVs. This process is standardized and repeatable; however, it has some drawbacks, such as low active functions being tested in a controlled environment. This sometimes causes huge variations in the range between driving cycles and actual on-road tests. This problem of variation can be solved by on-road testing and testing a vehicle for customer-based velocity cycles. On-road measurement may be high on active functions while testing, which may give an exact idea of real-world consumption, but the repeatability of these test procedures is low due to excessive randomness. The repeatability of these cycles is low due to external factors acting on the vehicle during on-road testing, such as ambient temperature, driver behavior, traffic, terrain, altitude, and load conditions. No two measurements can have the same consumption, even if they are done on the same road with the same vehicle, due to the
Rear-facing infant seats that are positioned behind front outboard vehicle seats are at risk of being compromised by the rearward yielding of occupied front seat seatbacks during rear-impact collisions. This movement can cause the plastic shell of the infant seat to collapse and deform, increasing the risk of head injuries to the infant. Current designs of rear-facing infant seats typically do not consider the loading effects from the front seatback during rear-impact situations, which results in weak and collapsible shell structures. Moreover, regulatory compliance tests, such as FMVSS 213, do not include assessments of rear-facing infant seats under realistic rear-impact conditions. as the bench used for the regulatory test lacks realistic vehicle interior components. This study emphasizes the need for revised testing methodologies that employ sled tests with realistic seatback intrusion conditions to facilitate the development of improved infant seat designs. Research shows that
In electric and hybrid vehicles, sound package optimization can follow a classical, proven, and structured approach for real-world loads, while also considering new transmission paths that might differ from those in traditional internal combustion engine vehicles. However, AVAS-induced interior noise is sometimes underestimated and therefore not taken into account during the optimization process. Nevertheless, especially at very low speeds, the presence of the AVAS can be perceived as unwanted noise inside the vehicle, potentially compromising interior comfort. In this study, a hybrid boundary element–statistical energy analysis (BEM – SEA) approach is applied to an SEA dual-motor electric vehicle demonstrator model equipped with a baseline, standard sound package to assess AVAS-induced interior noise. A standard AVAS actuator is modeled with a BEM model to compute the sound pressure levels on the exterior subsystems of the vehicle. These results are then transferred to the SEA model
The rapid evolution of modern automotive systems—powered by advancements in autonomous driving and connected vehicle technologies— pose fundamental challenges to design and integration. A specific challenge of these highly interconnected, software-driven systems is in ensuring their safety while avoiding spiralling costs and development times. This challenge calls for a more structured and rigorous approach to safety assurance than traditional methods. Traditional safety cases tend to take a linear, justification-focused approach that mainly focuses on positive assertions —compliance to safety —while giving limited attention to potential weaknesses, or gaps in supporting evidence. This practice may lead to criticism that such arguments are “too positive,” portraying an overly biased or optimistic view of system safety without sufficiently acknowledging areas of unresolved risk. As a result, conventional approaches for developing a safety case may overlook complex interactions
Quieter cabins in an automobile are the new era, they provide customers with pleasurable driving experience. Squeak and Rattle are spoil sport for any OEM that aim to improvise customer driving experience. Their nonlinear nature makes it difficult to formulate design frontloading methods. The issue of seals rubbing against the body & door interface is a clear sign of seal squeak & seal chucking. Seals are applied with anti-friction coatings to avoid stick slip phenomena between EPDM and painted panel. Primary root cause for seal squeak is coating erosion. The challenge lies in determining whether the body or the closure side contributes to the seal issue. This paper presents a distinctive approach for identifying the seal squeaking noise and enriches on the new modelling methods for seal interaction with door and body interfaces using FE software. The proposed method was able to highlight the locations along the door-body interface for squeak noise. The approach for reducing the
The customer perception of ride comfort with vehicle performance is the most important aspect in a vehicle design. The ride comfort and vehicle performance are influenced by driveline components i.e. propeller shaft phase angle, inclination angle and critical frequency of the driveline system. The optimization of the driveline system is essential to ensure the efficient and smooth power transfer. Propeller shaft is one of the critical components in the driveline to influence the vehicle performance. Propeller shaft characteristics influenced by several factors like vehicle max torque, propeller shaft joint type, materials properties, UJ phase and inclination angle and shaft unbalance value. The optimization of the above parameter within the tolerance limit enables to meet the required performance standard. Various methodologies are available to optimize these parameters to enhance the vehicle performance and comfort leads to customer satisfactions. This study focuses on the analytical
The design and improvement of electric motor and inverter systems is crucial for numerous industrial applications in electrical engineering. Accurately quantifying the amount of power lost during operation is a substantial challenge, despite the flexibility and widespread usage of these systems. Although it is typically used to assess the system’s efficiency, this does not adequately explain how or why power outages occur within these systems. This paper presents a new way to study power losses without focusing on efficiency. The goal is to explore and analyze the complex reasons behind power losses in both inverters and electric motors. The goal of this methodology is to systematically analyze the effect of the switching frequency on current ripple under varying operating conditions (i.e., different combinations of current and speed) and subsequently identify the optimum switching frequency for each case. In the end, the paper creates a complete model for understanding power losses
To conduct RDE (Real-Drive Emission) test on CEV (Construction Equipment Vehicle), the first step is to study the requirements set forth in the regulation [1, 2] for data collection, post-processing of data and emission calculation along with certain requirements for vehicle operation. Conducting tests on CEV machines poses a different set of challenges compared to on-road vehicles, the major one being the placement of PEMS (Portable Emission Measurement Equipment) on the machine under test. No singular method or mechanism can be specified to suit all types of machinery, although certain guidelines can be set for best practices. The requirement of running the machine on an actual duty cycle or a reference duty cycle requires a thorough study of the intended machine operation and also awareness on the multi-functionality setups offered for such machines by manufacturers, before deciding on a duty cycle to run during actual emission testing. Measurement of emission components such as