Meritor unveils inflation system for tractor tires

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NASHVILLE-The Meritor booth at the Technology & Maintenance Council’s 2015 Annual Meeting & Transportation Technology Exhibition has been humming this week with word of a new inflation system for tractors.

The MTIS Tire Inflation System for trucks automatically monitors tire pressure while the vehicle is in motion and will inflate an underinflated tire. If there are issues requiring continuous inflation, the MTIS system alerts the driver to check the tire or find service as soon as possible.

Joe ElBehairy, vice president, Engineering & Quality at Meritor, said that the MTIS is a two part system consisting of an electronic control module and up to six proprietary wheel-end seals.

“The two parts work hand in hand,” he said. “You can’t get the seals to work without the brains that control the air flow. Every time you pressurize the seal, it wears a little. Through our internal testing we have developed the logic and the algorithms around how to make it work while minimizing the time the seal is inflated.”

ElBehairy said Meritor had to develop a proprietary seal that rides on the polished surface of the axle spindle.

“We run air through that seal to get it out to the wheel end,” he explained. “It’s a little different with a trailer axle. On a trailer, you can pressurize the axle tube and run the air through a very small ‘pin seal’ out at the wheel end. It’s very easy to make those last, whereas with a drive axle, first of all you have an axle shaft running through it, and second, you can’t pressurize it because it has oil in it.”

The system is said to be fully automatic, with no driver intervention required. If the system cannot keep up with the air loss rate in the tire, it will alert the driver that service is required.

“The system is designed to last for the first-owner life of the vehicle, or 500,000 miles,” said ElBehairy, which is at about the same time you’d be servicing your wheel ends. “Our test truck now has 300,000 miles on it, and we have 15 fleet trucks running at five customers that have various generation of the product on them, some with upwards of 50,000 miles.”

“Maintaining proper pressure requires constant attention,” said Ken Hogan, general manager, Rear Drivetrain for Meritor. “In addition to reducing tire and fuel costs, the MTIS system enhances performance. Tire companies have stated that up to 80 percent of roadside tire failures are a direct result of creeping air loss.”

Although pressure leakage up to two percent per week is common for tire systems, additional pressure loss can be expected with puncture wounds from nails, a contaminated rim flange or bad valve stem.

ElBehairy said the system is expected to pay for itself within a year, based on estimates that it could prevent two tire failures per year. “It’s less about the cost of the tire, but the unplanned downtime,” he noted.

Validation testing with several fleets began in 2014 and will conclude in 2015. Chris Villavarayan, president of Meritor Americas, said that in addition to the five fleets already signed up for testing, a large number of fleets at TMC expressed interest in being in the test as well.

“Right now we have 15 trucks out there that we’re testing,” he said. “We had a bunch of other folks ask us, ‘Why not us?’, so we’re looking at doubling our fleet test out there.”

The company expects the MTIS system to be available to OEMs in North America on a limited basis in 2016. The system also has global application in the future.

Pressure Systems International, Meritor’s partner in the popular trailer inflation system, will supply some components for MTIS. All the engineering, validation and testing has been done at Meritor’s Troy, Mich., headquarters.

This story originally appeared on and was written with files from Deborah Lockridge, editor in chief of HDT magazine.

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Jim Park was a CDL driver and owner-operator from 1978 until 1998, when he began his second career as a trucking journalist. During that career transition, he hosted an overnight radio show on a Hamilton, Ontario radio station and later went on to anchor the trucking news in SiriusXM's Road Dog Trucking channel. Jim is a regular contributor to Today's Trucking and, and produces Focus On and On the Spot test drive videos.

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