Tire Monitoring Systems

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Tire Monitoring Systems
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Why ?

• Run flat tires
• People are lazy
• Safe braking
• Safe steering
• Tire failures
• Tire wear
• Fuel economy

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Who Needs It?
All manufacturers have some systems in place
because upcoming legislation requires it.
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When ?
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Summary of FMVSS No. 138 -Final Rule - Phase I
has a compliance date of November 1, 2003 - Final
Rule Phase I is applicable to 2-axle, 4-wheel
motor vehicles under 10,000 lbs GVWR - Does not
apply to o Vehicles with dual wheels on
an axle o Trailers Motorcycles
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Final Rule - Phase I - Requires the TPMS
telltale, mounted in the vehicles instrument
panel, to be illuminated within 10 minutes after
the inflation pressure falls below the acceptable
level - Permits the use of the following a)
Direct systems b) Indirect systems - Performance
options allowed 1) 4 tires _at_ 25
underinflation 2) 1 tire _at_ 30 underinflation
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Final Rule Phase II Effective date for Final
Rule - Phase II is November 1, 2006 Conduct TPMS
effectiveness survey (Direct/Indirect TPMS
vs. without TPMS) Based on survey
results, determine whether TPMS Phase I
requirements should be revised Publish Final Rule
- Phase II by March 2005
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Costs

• Aftermarket installed
• 400 and up !
• For factory to install
• The "direct" systems cost 66.33 per vehicle
• for "indirect" systems, 30.54 per vehicle

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How?

• There are two main types
• Direct
• Indirect
• There are variations of each , and hybrid systems

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Two Main Types

• Direct.
• Each wheel has a sensor built in to monitor
  the tire pressure directly
• Some monitor temperature.

• Indirect
• Vehicle uses ABS components while vehicle is
  moving to calculate mismatched wheel speeds.

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Direct

• Tire pressures are monitored at each wheel
• Pressures sent to processor using wireless
  technology
• Processor calculates and signals display

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Direct

• 3 Types of Alerts
• Pressure Status
• Low Pressure alert
• Low Pressure warning

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Direct System Comparisons

• Cons
• Price
• Sensors need batteries
• Complete new system
• Added weight
• Severe drops in temperature reduce battery
  capacity

• Pros
• Accurate within 1 psi
• Fast updates every 30 seconds
• Actual pressure reading

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Indirect

• ABS hardware utilized
• Wheel speeds sent to processor using existing
  hardware
• Processor calculates and signals display

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Indirect System Comparisons

• Pros
• Price
• Uses existing hardware
• Needs only software and display

• Cons
• Lower accuracy
• Not all vehicles have ABS
• Only works with vehicle in motion
• Will not tell if all 4 tires go down

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Display Types

• Individual tire monitoring
• Individual LED go / no go
• System failure light

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Direct Sensor Types

• Electronics in cap
• Ease of installation
• Lightweight so no re-balancing
• Easy to steal

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Direct Sensor Types

• Internal mounted
• Part of valve stem
• PACIFICLexusstandard on SC430

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Direct Sensor Types

• Internal mounted
• Part of valve stem
• SCHRADERFordChryslerGMNissan/Infiniti

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Direct Sensor Types

• Part of valve stem
• Internal mounted
• BERUAudi/VolkswagenBMWLand RoverMercedes-Benz
  Porsche

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Direct Sensor Types

• Strapped to wheel
• Requires counter balance
• Requires tire to be removed for installation

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Indirect Sensing

• Uses the vehicles ABS sensors
• 75 of cars manufactured have ABS
• Many entry level cars do not have ABS

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Power Supplies
Some direct sensors use batteries Some use Piezo
electric generators Some use transponders
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Batteries

• Direct monitoring transmitters need power
• Lightweight batteries are required
• Long life is expected

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Batteryless TPMS
The central unit thus transmits signals as well
as receives, and a transponder (which replaces
the transmitter) uses the energy of the signals
received from the central transceiver to send a
return signal to the central transceiver.
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Service Notes
Caution must be used when using tire machines
! Tire can be ruined by mechanical contact with
the machine or contact with the bead

• Processor must be reset manually after inflation
  for GM or BMW indirect TPMS

Different manufacturers have different
procedures and tools for resetting the
processors.
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Service Tips
Stay clear of wheel sensor to prevent damage
With tire removed, check condition of wheel
sensor - no need to remove sensor from wheel to
do this! Before mounting tire, check date stamp
on sensor Replace sensor if over 5 years old
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Service Tips

• If the battery is disconnected or run down the
  processor must be re-programmed
• If tires are rotated, the processor must be
  re-programmed
• If the sensor is replaced the processor must be
  programmed
• Some batteries are not serviceable , replace
  sensor

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Other Products
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Valve Cap Gauge

• No battery power
• Low cost
• At wheel monitoring

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Cycloid

• Continuously operates as a "trickle charger" for
  tires, keeping them at their proper pressure.
• Hub mounted and easily installed in minutes
  Light weight, tough and virtually
  indestructible.
• Centrally located tire valves on each pump for
  easy tire pressure monitoring.