Expo presenters talk fuel tanks, batteries

Novi, MI. The Automotive Testing Expo got underway here Tuesday with presentations on various aspects of automotive technology, from tires to fuel injectors. Of course, critical to any automobile is an energy source—and a way to store that energy. If your car is powered electrically, you’ll need a battery, and if it's powered by gasoline or diesel, you’ll need a fuel tank. 

Test of the latter was the topic addressed by Nick Jaksa, managing director, BIA North America. His company builds a multi-axis simulation table that mimics real road conditions so the tank can be evaluated in the lab. In addition to vibration, the 6-DoF table can tilt to simulate lateral acceleration, which otherwise would require a great deal of space in a lab setting.

The system helps evaluate sloshing and vapor pressure control and validate fuel-gauge algorithms. It also pumps fuel from the tank under test to simulate fuel consumption, recovering all fuel used in the test. It complies with the European ATEX directive.

The system includes a controller incorporating modular I/O boards that can communicate via CAN, LIN, and FlexRay. Jaksa said similar turnkey systems can serve agricultural, aerospace, marine, and rail applications.

Precision battery test was the topic of Alvaro Masias, a research engineer at Ford Motor Co. Batteries, he said, are an important part of increasingly electrified vehicles—including cars with start-stop capability, mild-hybrid vehicles, and strong-hybrid and plug-in electric vehicles. Vehicle batteries, he said, have evolved from lead-acid through NiMH and on to Li-ion, which is the battery technology of choice today.

Batteries for consumer products, Masias said, typically operate for about 500 cycles, or one or two years. Vehicle batteries require much longer life. He also said levels of charge depletion affect battery life—a hybrid vehicle battery may often operate in a state between depletion and fully charged, while an all-electric vehicle’s battery may experience more depletion.

In any event, he said, an effective way to test batteries is required to determine how much capacity will remain after 10 or 15 years of operation. An accurate prediction of end-of-service capacity, ha added, can make it unnecessary to build in extra capacity up front.

He explained that designers of computer battery systems can measure decay in units of 500 ppm. What’s required for vehicle batteries, he said, is a 200-A tester that can measure decay at 50 ppm. A research project conducted in conjunction with Sandia National Laboratories and Arbin Instruments, he said, has resulted in a tester that achieves 150 ppm—“We need to walk before we run,” he said—and more work needs to be done. Ford, he concluded, does not want to be in the business of building battery testers, and he expects companies like Arbin to build commercial battery-test products.

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