Accu-pressure sensor

Objective

The objective of tire pressure monitoring systems is to improve commercial motor vehicle safety by assisting drivers and fleet managers in efficiently monitoring proper tire pressure. By automatically measuring and indicating air pressure information to fleet operators and drivers, tire pressure monitoring systems can be valuable aids for proper tire maintenance that will enhance the safe operation of commercial motor vehicles.

Description

Tire pressure monitoring systems automatically detect and relay tire air pressure information with sensors attached to the tire, wheel, or valve stem. Some tire pressure monitoring systems may be integrated with tire pressure equalizer or maintenance systems that monitor and automatically inflate tires to a specific tire pressure.

Tire air pressure information can be indicated by different means. The interface for some tire monitoring systems provides information in the form of alerts from on-vehicle wheel-mounted or dash-mounted display units when tire pressure changes have occurred. Other systems involve the use of hand-held or drive-by readers to capture and instantly report tire pressure and possibly other maintenance information. The information from these systems can also be reported in a fleet-specific manner via an internet server to maintenance managers for tire monitoring and tracking purposes. Some systems utilize wireless communications to monitor air pressure.

One tire pressure monitoring system installed over the tire valve stem provides a color-coded indicator of green for normal tire pressure, yellow for slightly under-inflation, and red for severely under-inflation. Another tire valve stem system provides a digital tire pressure reading. These systems are installed on individual tires; therefore, a walk-around inspection is required to check the tire pressure indications.

Other tire pressure monitoring systems use wireless radio frequency signal technology to provide low tire pressure warnings through audible or visual warnings (i.e., lights, graphical displays) on a dash-mounted display or hand-held reader. Some of the digital or graphical vehicle interfaces show the current air pressure within each tire along with the tire temperature. One system provides a graphic that indicates suggested maintenance action. In the event of multiple warnings, this system cycles through information about each affected tire. Another system reads and transmits tire pressure and temperature data at set time intervals, such as every four minutes. However, if the tire pressure changes by 3 psi, the sensor transmits the information immediately to a receiver which sends the information along with an alert to the driver display unit. Using the display unit, the driver can read information relating to tire pressure, temperature, and pressure at each wheel position.

Tire pressure monitoring systems are subject to several limitations. One limitation of tire pressure monitoring systems that are attached to the tire stem or wheel rim is the sensor could be damaged by contact with objects such as curbs, during turning, parking, and other maneuvers. Valve-mounted systems are also susceptible to loss because they must be removed as wheels are mounted or dismounted during vehicle maintenance or inspection activities. Reinstalling these systems on the proper wheel is critical for maintaining proper programming in the display units since swapped sensor locations lead to swapped sensor readings. Furthermore, tire pressure monitoring systems that utilize radio frequency communications to transmit data between sensors and the display unit or electronic control unit may require additional on-board antennas to receive the sensor signals from trailer or tag axle tires due to the long length of the truck. In addition, a loss of signal from the sensors may result from damaged or disconnected antennas.

SmarTire Pressure Alert

Application

Tire pressure monitoring systems let the driver know when tires are under inflated so that corrective measures can be taken to protect the tires and possibly prevent crashes than can occur due to low pressure tires.

Commercial motor vehicle tires can lose air pressure for several reasons. Air can escape between the bead (edge of a tire that sits on the wheel) and wheel, as well as through improperly tightened valves, torn rubber grommets, or blocked valve cores. Tires that are improperly inflated can run hot, damaging the casings and sidewalls and lead to serious tire problems that can cause crashes due to poor handling, hydroplaning, tire blow-outs, and vehicles that are stranded on the roadway.

As of November 2006, the Transportation Recall Enhancement, Accountability and Documentation (TREAD) Act mandated that all newly manufactured light vehicles be equipped with tire pressure monitoring systems.

Operations and Benefits

Properly maintained tires can provide safety, operational reliability, and economic benefits. Vehicle tires that are improperly inflated can impact the life of the tire and lead to catastrophic tire failures. Through the aid of tire pressure monitors, tires can be properly maintained, and crashes caused by tire blowouts, vehicle handling characteristics, hydroplaning, and other tire-related issues can be prevented resulting in savings of life, property damage, time, and congestion.

One of the largest maintenance costs for commercial vehicle fleet operators are tire-related expenses that include tire maintenance and replacement. Under-inflation reduces the useable life of tires due to overloading, which causes deformation of the tire sidewalls, and to heat generation inside the tire, which weakens the adhesion between rubber and steel cords. In addition to impacting the tire’s useful life, both under-inflation and over-inflation cause irregular and accelerated wear patterns that impacts tread wear. Increased heat and overloading can increase a tire’s susceptibility to punctures and cuts, cause the loss of tire tread, and reduce the number of times that a tire can be safely re-treaded. Furthermore, fuel economy can be impacted by inadequate tire inflation, because additional power is required to move the vehicle due to the increased rolling resistance. Economic benefits from tire pressure monitoring systems include increased tire life and reduced tread wear through proper tire inflation.

Tire pressure monitoring systems for commercial motor vehicles can specifically aid drivers and fleet operators in easily and economically maintaining normal tire pressure in all tires for optimum safety and operation of the vehicle. Maintaining proper tire pressure for commercial vehicle tires can be time-intensive, especially for large fleets. For each 18-wheeler pre-trip inspection, it takes approximately 25 minutes to check all of the tires and inflate low-pressure tires to the recommended target pressure level.

Cost

The installed cost of tire monitoring systems depends upon the type of system purchased and how they are purchased.

Easily installed tire pressure sensors over tire stem valves that display color-coded results cost approximately $12 to $15 per stem valve. The costs of systems that include a driver-interface and tire stem valve sensors range from approximately $500 for a six-wheel system to $1,800 for an eighteen-wheel system. These systems can be purchased on-line or directly from the manufacturer and specified distributors.

Advanced systems that include the driver-interface and sensors attached either to the stem valves through the wheel into the tire well or within the tire well cost approximately $1,200 to $2,100, depending upon the type of system, number of tires, and installation requirements. These systems are available directly through the product manufacturers or original equipment truck manufacturers. Systems that require the use of handheld readers cost approximately $6,000 for each reader, and gate readers range from $10,000 to $12,000.

Vendors

ArvinMeritor
3023 Interstate Drive
San Antonio, TX 78219
Phone: 210-222-1926
Fax: 210-222-2013
www.arvinmeritor.com

Accu-Pressure Safety Caps, Inc.
150 E. Sample Road, Suite #100
Pompano Beach, FL 33064
Phone: 954-782-9866
Toll Free: 1-800-914-5003
Toll Free Fax: 1-800-914-4899
http://www.accu-pressure.com

Advantage PressurePro, LLC
205 W. Wall Street
Harrisonville, MO 64701
Phone: 816-887-3505
Toll Free: 800-959-3505
Fax: 816-887-3705
www.advantagepressurepro.com

Dana Corporation
Commercial Vehicle Systems
P.O. Box 4097
Kalamazoo, MI 49003-4097
Phone: 1-800-826-4357
www.roadranger.com

Doran Manufacturing, LLC
2851 Massachusetts Avenue
Cincinnati, OH 45225
Phone: 513-699-6237
Toll Free: 866-816-7233
http://www.doranmfg.com

Fleet Specialties Company
Tire Sentry Division
31328 Via Colinas
Westlake Village, CA
P.O. Box 4575
Thousand Oaks, CA. 91359
Phone: 818-889-716
Fax: 818-889-3982
www.tiresentry.com

HCI Corporation
11245 183rd Street
Cerritos, CA 90703
Phone: 562-926-7123
www.tiresafeguard.com

Meritor Heavy Vehicle Systems, LLC
2135 West Maple Road
Troy, MI 48084
Toll Free: 800-535-5560
www.meritorhvs.com

Michelin North America,Inc.
P.O. Box 19011
Greenville, SC 29602
Phone: 864-458-5476
www.michelintruck.com

Prime Time Solutions, Inc.
23 Garfield Street
Torrington, CT 06790
Toll Free: 800-333-9325 ext. 204
www.accupressurecaps.com

Pressure Systems International
3023 Interstate Drive
San Antonio, TX 78219
Phone: 210-222-1926
www.psi-atis.com

SmarTire Systems, Inc.
13151 Vanier Place
Richmond, BC, Canada V6V 2J1
Phone: 604-276-9884 ext. 308
www.smartire.com

Safer Corporation
750 Grant Avenue, Suite 150
Novato, CA 94945
Phone: 415-898-2000
Toll Free: 877-777-2337
www.saferco.com

STEMCO LP
300 Industrial Blvd.
P.O Box 1989
Longview, TX 75606-1989
Phone: 903-758-9981Toll
Free: 800-527-8492
Fax: 903-232-3508
www.stemco.com

WABCO North America
2550 South Telegraph Road, Suite 105
Bloomfield Hills, MI 48302
Phone: 248-451-0416
Fax: 248-451-0222
www.wabco-auto.com