Mobility & Automotive
Reliable leak testing in an evolving industry
Changes in the automotive industry make leak testing even more important
You are already familiar with a wide variety of leak testing tasks in the production of automotive components, such as fuel tanks, injection systems, airbag gas generators. Now, electric cars (EVs) and fuel cell cars (FCVs) add similar and often even more stringent leak tightness requirements. Whether it's individual Lithium-ion battery cells or battery packs, the bipolar plates of hydrogen fuel cells or the ADAS sensors of autonomous vehicles - INFICON offers you the optimal leak detection solution for all automotive testing tasks.
As automobile manufacturing evolves, leak testing will continue to be an indispensable element of quality assurance in the production of more and more automotive components. Our experts will be happy to advise you on the ideal solution for your specific application combining maximum reliability, high throughput and moderate costs.
With the increasing success of electric cars (BEVs / PHEVs) demand for traction batteries is also increasing. For you, it is important to ensure at every stage of production that the electrolyte does not leak out of the lithium-ion battery cells or come into contact with water or humidity - so that it does not react to form hydrofluoric acid. Of course, water must not be allowed to penetrate battery packs and modules, if only because of the risk of short circuits.
With INFICON, you can ensure compliance with sealing requirements. For example, our ELT3000 leak detector is the first device ever that can test already filled lithium-ion battery cells for leaks of just a few micrometers in diameter - because it directly detects escaping electrolyte solvent. This enables you to achieve the targeted ten-year service life. Devices such as our LDS3000 or LDS3000 AQ are suitable for your leak tests on housings, cooling lines or electric motors. And their high gas flow makes the XL3000flex and Protec® P3000XL ideal for automated robotic sniffing leak detection of assembled battery packs.
The hydrogen technology of fuel cell vehicles (FCVs)brings its own leak testing requirements - for hydrogen tanks and lines, for hydrogen recirculation, and for the bipolar plates and membrane electrode assemblies (MEAs) that you later assemble into fuel cell stacks. Typical fuel cell failure modes include crossover leaks between anode and cathode or overboard leaks at seals, through which hydrogen reacts uncontrollably with oxygen.
Hydrogen should also not be allowed to leak into the cooling circuit. For all hydrogen carrying components, use the smallest possible reject leak rate in the range of 10-5 mbar∙ l/s, very similar to the settings for CNG / LNG components. There is hardly any way around test gas-based methods when hydrogen is used. Some fuel cell components are best tested with short cycle times in a vacuum chamber. For sub-assembled FCV systems like hydrogen tank systems, automated robotic sniffer leak testing is recommended.
In the powertrain of vehicles with internal combustion engines (ICEs), there are a wide variety of components that you must leak test during the production process. Whether it's a matter of pre-testing gear box housings that are still empty or the oil-tightness of the automatic torque converter. You also have to leak test a dual-mass flywheel, as well as an intercooler.
For all these leak testing tasks, traditional methods such as pressure drop tests reach their limits. Intercoolers are sensitive to temperature fluctuations by their very nature. Temperature changes, however, can render the results of a pressure test completely unusable. A much more reliable solution are the tracer gas-based leak testing methods from INFICON - such as the LDS3000 in combination with a vacuum chamber or the LDS3000 AQ for the cost-effective accumulation chamber.
Due to stricter standards to prevent hydrocarbon emissions, the leak rate specifications for fuel tanks and fuel injection systems have steadily tightened worldwide in recent years. Fuel tanks and fuel lines are therefore often tested against leakage rates of 10-4 to 10-6 mbar∙l/s. Water bath and pressure methods cannot test to such low leak rates. Only tracer gas-based methods can do this job.
Accurate leak testing is also indispensable if you manufacture fuel injection valves or fuel pumps. For common-rail injection systems, the requirements are often even stricter because of the high operating pressures. Components used in common-rail systems are leak tested against leak rates in the range of 10-4 to 10-6 mbar∙l/s. Leak detectors like the INFICON LDS3000 and LDS3000 AQ have proven themselves time and again in industrial use for these applications.
R1234yf has now replaced the climate-harmful R134a in almost all car air conditioners. The new refrigerant can be operated in AC systems at the usual pressure of 10 to 15 bar. Some manufacturers in the luxury segment avoid any potential problems with the flammable R1234yf by using CO2 (a.k.a. R744) at higher pressures, and also with greater design complexity. In any case, follow the established rule of thumb of a maximum leak rate of 2-5 g of refrigerant per year.
This refrigerant leak rate is equivalent to testing against a helium leak rate of 2∙10-5 mbar∙l/s. During production, most air conditioning components are tested against leak rates in the range of 10-5 mbar∙l/s. When leak testing with the INFICON LDS3000 in the vacuum chamber, you achieve particularly short cycle times. Evaporators, condensers, hoses or filling valves can also be leak tested with the more cost-effective accumulation method and the LDS3000 AQ.
Aftermarket MAC repair must be performed thoroughly and properly the first time to avoid repeat repair work and unsatisfied customers. With INFICON Automotive Service Tools (AST), repair technicians can be confident they will find small leaks that would have caused big problems. This line of handheld tools is designed specifically for the automotive aftermarket repair industry, and can be trusted for any application, from standard refrigerants such as R134a and R1234yf, to CO2 and hydrogen forming gas.
All vehicle components that are directly relevant to safety have special quality requirements - with corresponding demands on leak tightness. Brake hoses, brake fluid reservoirs and brake boosters, for example, should typically be tested against leakage rates in the range of 10-3 to 10-4 mbar∙l/s, often executed by helium testing in the accumulation chamber.
Airbag gas generators are tested by bombing. First the airbag igniter is subjected to helium overpressure, then it is tested in a vacuum chamber to measure how much helium escapes from the test part again. Pyrotechnic airbag gas generators must be protected against intake of humidity - corresponding to a reject leak rate in the 10-6 mbar∙l/s range.
The leak rate specifications for airbag cold gas generators are somewhat higher. Their helium-argon mixture must maintain its overpressure for more than 10 or 15 years. To test for this against the even smaller helium leak rate of 10-7 mbar∙l/s, vacuum leak testing with the LDS3000 or the Modul1000 is the established method of testing.
Autonomous or semi-autonomous vehicles with Advanced Driver Assistance Systems (ADAS) use an array of sensors. Fail-safety is a key criterion for safety-critical ADAS sensor technology. That's why, for most manufacturers, a Six Sigma approach with 3.4 failures in a million is inconceivable - a “zero-defect” strategy is often applied here, with less than one failure in a billion parts.
For LIDAR as well as RADAR sensors, for example, fogging must be avoided. So to eliminate the possibility of moisture ingress, and thus fogging, these sensors must be gas-tight equaling a leak reject leak rate in the range of 10-6 to 10-7 mbar∙l/s in quality control during manufacturing. Helium vacuum leak testing with an instrument like the INFICON LDS3000 is the method of choice for many manufacturers.
After final assembly, all connections between pretested subsystems and components need to be leak tested. INFICON offers you a variety of sniffer leak detectors for this purpose. The procedure: You fill the component with the test gas and then guide the sniffer tip of the device either manually or automatically with the help of robots over the critical areas. Helium or forming gas are suitable test gases, as are gaseous operating media such as R1234yf or CO2.
INFICON refrigerant leak detectors, like the HLD6000 and the Ecotec E3000, are recommended for the connectors of air conditioning systems, fuel injection systems or battery thermal management systems. The Sensistor Sentrac® sniffer leak detector, which uses low-cost forming gas, is used for testing oil and water circuits of combustion engines. Tracer gas sniffer leak detectors, such as the INFICON XL3000flex and the Protec® P3000XL are suitable for dynamic robotic sniffing leak detection because of their high gas flow.
The need to improve AC repair skills is now more important than ever, and solid leak detection is an imperative part of repair best practices. This is driven by several factors affecting the automotive aftermarket including the rising cost of R1234yf, the RRR leak test misconception, and the connection between climate control and battery operation of electric vehicles.
With the increasing price of refrigerant, technicians need to be able to make repairs correctly the first time. When a leak is missed due to faulty or insufficient leak testing, the result will be a customer comeback, with likely all of the expensive refrigerant drained from the system. INFICON Automotive Service Tools (AST) offers a full line of electronic leak detectors that help technicians catch leaks and avoid customer comebacks.
The RRR machine, an equipment requirement for shops that perform AC repair in the U.S., has a leak testing function that checks for large, gross leaks. The idea that this equipment can detect all problematic leaks provides a false sense of security that will result in costly re-repairs. In order to eliminate customer comebacks, technicians should use a dedicated electronic leak detector that can find small leaks that can cause large issues, such as AST300PPM or AST200IR.
The growth in the electronic vehicle market presents yet another reason to use an electronic leak detector. The climate control system in an EV also controls the battery compartment. If the AC is not working, the vehicle will shut off for safety reasons. Because of this, it is crucial that leak testing best practices are followed for EV AC repair.
From AST100, perfect for everyday RAC maintenance, to the intrinsically safe AST100FG that makes it safe to find leaks with hydrogen forming gas, INFICON has a leak testing solution for your application.