Browse Topic: Leak tests
This recommended practice (RP) establishes nondestructive in-line production test methods for evaluating the water leak tightness of propulsion battery packs. It aims to achieve results equivalent to the IEC 60529 standard’s IPX7 level using the Selected Equivalent Channel (EC) method defined in SAE J3277. This RP provides guidance for system setup, tooling design, validation, and leak test procedures. It acknowledges the limitations of certain battery pack designs and recommends appropriate air or tracer gas leak tightness technologies. Specifically, this RP covers nondestructive end-of-line leak testing for: Battery pack assembly: Ensuring protection against water ingress into the battery pack. Coolant system: Verifying the integrity of the coolant system and preventing coolant leaks into the battery pack.
This specification provides requirements and procedures for gas-pressure leak testing of parts.
Lithium-ion battery systems are an energy source for a variety of electric-vehicle applications due to their high energy density and low discharge rates. Battery packs, whether made of prismatic, cylindrical, or pouch cells, are cooled by common automotive thermal management systems.
In current competitive environment automobile industry is under heavy pressure to reduce time to market. First time right design is an important aspect to achieve the time and cost targets. CAE is a tool which helps designer to come up with first time right design. This also calls for high degree of confidence in CAE simulation results which can only be achieved by undertaking correlation exercises. Fuel tank is one of the important system in vehicle. At the validation stage leak test is carried out to find the leakage in the tank. This test is regulatory requirement which also ensures that the spot weld joineries have sufficient strength. Same test was mapped in CAE and high stress locations were identified. In test, strain gauging was done at the three selected locations. Paper highlights the test vs. CAE strain correlation and its finding. The effect of thinning is also discussed for the strain correlation of fuel tank.
Thin films and vacuum technology are used frequently throughout advanced, environmentally friendly automobile manufacturing. From automotive light-weighting of conventional ICE automobiles, to hybrid and EV manufacturing, thin films deposited in vacuum systems, vacuum heat-treating, and vacuum leak testing are a major part of automotive device, component and sub-assembly manufacturing. Starting with new applications of polycarbonate glazing by plasma coating, which provides lower CO₂ emissions, greater design freedom and cost reduction through parts consolidation. For high-strength, light-weight automotive steel stampings used in chassis and body parts, wear-resistant coatings are applied in vacuum systems to provide wear protection and to extend the stamping die lifetimes. Thin film vacuum equipment is also used for the manufacturing of: control circuits, film capacitors (EVs, PHEVs and HEVs), power ICs (hybrids), sensors (air bag, tire pressure, etc.), secondary batteries (EVs), coatings for mirrors, interior lighting, lamps (LEDs and reflectors), front grilles, touch-screen displays used in navigations systems, and gauges. Vacuum brazing is used to fabricate automobile radiators and air conditioners. Vacuum leak-testing is used to test the integrity of a wide-array of components, from tire rims and heat exchangers, to transmissions, braking systems, airbag inflators, and torque converters. This paper will elaborate on the vacuum equipment and processes used in advanced, in-vehicle product solutions.
O-rings are regularly utilized as a means of creating a seal between two components. Since the introduction of mini-concentric fuel pressure regulators, several issues have arisen related to assembly. In many cases, severe leaks are masked by lubricants used to aid in assembly. A lubricant is required which will not mask such leaks. The purpose of this study is to determine the impact on assembly between alcohol and oil based lubricants and to determine the optimum assembly parameters when using alcohol lubricants. Several variables were identified as being major contributors to the assembly process. A total of 6 variables were chosen to be examined as well as 2 noise factors. Each variable, or factor, was assigned several levels for this experiment. Several measurables were defined outputs from the experiment. To maximize the efficiency of testing, an orthogonal array was used to structure the experiment. An L18 orthogonal array was chosen composed of 72 trials. When conducting a trial, the CNC press was used to control insertion rate. Insertion force data was collected electronically by the CNC press controller. After assembly each sample was leak tested using an air pressure test. Samples were then disassembled to search for and examined O-ring damage. Upon completing the study, only one assembly process parameter was found to be significant for successful assembly. The dominant process parameter was found to be the assembly lubricant with a 70% alcohol based 30% water mixture being the optimum.
This SAE Standard applies to electronic probe-type leak detectors used to service motor vehicle passenger compartment air-conditioning systems. This document does not address any safety issues concerning their design or use.
Determination of appropriate leak tightness specifications for production leak testing of fuel system components has challenged the automotive industry for many years. This process has become more complicated as hydrocarbon emission regulations have been lowered (US-EPA, CARB LEVII, Euro5, etc.). Application of the equivalent channel (EC) concept can significantly simplify the process of determining leak tightness specifications. This paper describes the test procedure and results of a hydrocarbon emission study designed to define a critical geometry (known as Equivalent Channel-EC) that will plug after exposure to gasoline, resulting in no HC emission due to leaks during Vehicle SHED (Sealed Housing for Evaporative Determination) tests. This critical geometry will stop any measurable hydrocarbon leakage after enough time has elapsed for the channel to plug. Micro-channels of several diameters and lengths were tested in a Micro-SHED at 40 degrees Celsius for 24 hours. SHED tests were performed on EC's with direct liquid gasoline contact at 345 kPa-Gage (50 psig). These test parameters were selected to match typical automotive operating conditions of gasoline fuel system components. Gasoline used was per EPA Tier 2 EEE specification as required for standard emission tests. Nitrogen and flow rates of all micro-channels were measured to establish minimum production leak test tightness specifications required to ensure defects larger than the critical geometry (Equivalent Channel) are detected during a leak test. EC flow rates were measured at several pressures to facilitate establishing a flow curve. The flow curves can be used to calculate flow rate at any test pressure between 68.9 and 1034.2 kPa-Gage (10 and 150 psig). This method of establishing leak tightness specifications effectively ensures no hydrocarbon Vehicle SHED contribution due to component leaks as is independent of specific production leak test methods and test parameters.
Herschel is the fourth cornerstone mission in the European Space Agency (ESA) science programme. It will perform imaging photometry and spectroscopy in the far infrared and submillimetre part of the spectrum, covering the 57-670 µm wavelength range. This successor of the Infrared Space Observatory (ISO) is scheduled to be launched by an Ariane 5 in 2007. Once operational Herschel will offer a minimum of three years of routine observations. EADS-ASTRIUM, in charge of the Extended Payload Module, has involved AIR LIQUIDE in the design and manufacturing of major components of the spacecraft cryostat: the two Helium Tanks, all Thermal Links [1.6 K - 9 K], the Optical Bench Helium Cooling Loop, the three Thermal Shields and all the Helium System Tubing from the tanks to the Cryostat Vacuum Vessel. All these elements contribute to the final aim of the system to provide the required cold environment to the Herschel Focal Plane Units. This paper presents the items provided by AIR LIQUIDE, from design to qualification. Particular emphasis is given to the leak test with superfluid Helium of the main tank equipped with its tubing.
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