Treading into new areas of excellence

THE COMMERCIAL Vehicle Systems group of Dana Corp has added three new features to its Dana Spicer Tire Maintenance System (TMS) for trailers.

“We've redesigned our electronic control unit (ECU), improved the wire harness, and added the option of selecting additional protection from outside abuse,” said Jim Beverly, chief engineer for advanced chassis control systems at Dana.

Beverly said the ECU update provides the convenience to reprogram, or re-flash, the ECU through the serial data-link connector to incorporate new features in the future.

Meanwhile, a new wiring harness has been “bullet-proofed,” said Beverly. New over-molds at key connection points better protect all splices and breakout points. Additional protection of the tire hose connection to the hubcap may be specified with an optional guard, which helps prevent damage that might result from operators stepping on the wheel end to secure cargo and/or during tie-downs.

Spicer TMS units are manufactured and assembled at Dana's plant in Henderson KY and are available for factory and off-line installation on all makes and models of trailers manufactured in North America.

“The key to reduced operating costs with respect to tires is maintaining proper inflation pressure throughout the life of a trailer,” said Beverly. “We accomplish this by actually measuring tire pressure, maintaining tire pressure automatically, and signaling a warning only when an adjustment is necessary.”

Beverly said Spicer TMS relies on the success of an ECU to ensure robust, yet simple to use, performance. Vehicle operators are only notified if tire pressure falls below a pre-determined level, which is typically set at 10% below the desired cold-tire pressure setting. Additional system reliability is achieved through certain design features.

With a patented two-solenoid manifold design, Spicer TMS allows for non-pressurized seals and lines. Other systems, where seals and lines are subject to constant pressurization, are far more likely to result in premature failures while being continuously pressurized for hundreds of thousands of road miles when inflation is not required.

A checkup every 10 minutes

Spicer TMS checks tire pressure on power-up, and after that, every 10 minutes of operation. When a low tire is detected, the system directs air to the underinflated tire until proper inflation pressure is achieved. Meanwhile, a built-in fault tolerance in the control strategy ensures fail-safe operation. In-line check-valves provide tire isolation in the case of a damaged tire or hose.

Another design feature, said Beverly, is the elimination of any requirements for venting at the wheel end. “Other systems must have large vents at the wheel end so that the hub is not pressurized in the event of an air seal or line leak,” said Beverly. “Even a tiny leak of the high air supply pressure in the wheel end can cause catastrophic consequences, especially in continuously pressurized inflation style systems. On top of that, these high-flow hubcap vents are susceptible to contamination and water ingestion.”

Conversely, wheel end venting on Spicer TMS is provided back through the axle tube to virtually eliminate any potential problems. Vent lines routed from the axle to the frame rail provide additional product integrity.

Air routed by sealed conduits

Dedicated hoses in the trailer axle tube improve integrity. Dana's design permits the air to be routed via sealed conduits that results in no presence of pressurization in the axle tube, thereby preventing contamination in the hub, air seal, and check-valve.

This system is backed by a three-year, unlimited mile warranty. No special maintenance is required for the life of the product, though periodic inspections are suggested.

Dana's experience with tire pressure management technology began with the military, which has been spec'ing Dana Spicer Central Tire Inflation Systems (CTIS) for two decades. Despite the name, these systems are noted for their ability to deflate tires to provide enhanced mobility in soft soil terrain.

The military now requires new medium and heavy tactical trucks to use CTIS as an ally. In answering the call, Dana has supplied the vast majority of these systems.

Those military vehicles went on to provide Dana with the ammunition it needed to further expand their marketing of CTIS. Today, it has virtually displaced all-wheel drive (AWD) in vocational applications where soft soil is prevalent. Every major commercial vehicle OEM in North America now offers Dana's Tire Pressure Control System (TPCS), Dana's commercial version of CTIS as an option.

In case of future governmental legislation that may someday result in new rules regarding low tire pressure warning systems on commercial vehicles, Dana will be well prepared to answer the call. “Dana Spicer TMS does not just inflate the tires, but actually measures the tire pressure,” says Beverly.

Mark Holley, product manager, trailer and advanced chassis control systems for Dana, also envisions Spicer TMS eventually serving as the foundation to bring about better, overall vehicle well-being. “We see future opportunities where our system interfaces with other vehicle sensors, such as those associated with brake wear and wheel end temperature,” said Holley.

For more information, visit www.roadranger.com or contact Roadranger Marketing, PO Box 4013, Kalamazoo MI 49003.

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