Transense Technologies plc – 26/01/05 – Issue 21

SAW based TPMS the Next Revolution for Tires

tire technology EXPO 2005

Dr R Lohr and P Vickery

Cologne, Germany 22-24 February 2005

Transense Technologies plc

Transense Technologies plc – 26/01/05 – Issue 22

Business Model

§ Transense is a technology transfer company

§ Develops IPR in surface acoustic wave (SAW) based wireless, batteryless, sensors for the automotive market

§ Two current business streams:

Tyre Pressure Sensor (TPS) Systems: In-Tyre and On-Valve

Torque Sensor (TQS) Systems: Powertrain and EPAS

§ Licenses Application companies (Tier 1s and Tier 2s) and Supplier companies to create virtuous supply chains

§ Provides engineering support to licensees through:

Provision of prototype systems

Assistance in manufacturing process development

§ Derives revenue from licences, engineering support and ongoing royalties

Transense Technologies plc – 26/01/05 – Issue 23

Tyre Pressure – Regulation

Run-flat tyres

- Technology is becoming increasingly popular dominated by Michelin and licensees

- Dash board low pressure warning mandatory

US TREAD Act – November 2000

- Transportation Recall Enhancement, Accountability and Documentation Actpassed following a spate of SUV rollovers attributed to tire condition

- 2003 Federal court ruling that indirect systems cannot comply with TREAD Act

- The National Highway Traffic Safety Administration (NHTSA) have mandated that: from Sept 2005 a 4 tire TPMS, capable of detecting more than 25% under-inflation and warning the driver, be progressively introduced on all vehicles up to 10,000lbs

Europe and Japan

- have been introducing TPMS for several years especially on up-market vehicles

- implementation driven by safety and quality considerations

Transense Technologies plc – 26/01/05 – Issue 24

Technical Collaboration

§ Universities:Oxford Brookes University (SAW design)

Manchester University (Microsystems & Thin Film)

Cranfield University (Gyro & Thin Film)

Sheffield University (Electric Motors & Vehicles)

Oxford University (Control & Nanotechnology)

Nottingham University (Gyro)

Leuven University – Belgium (Antennae)

St. Petersburg University – Russia (SAW Research)

§ Institutions:

National Physical Laboratory (Microscopy)

Instron (Materials testing)

Transense Technologies plc – 26/01/05 – Issue 25

§ Protection of Intellectual Property

Essential where potential application customers is numbered in 100s of millions

§ 20 Granted Patents

Exclusive automotive rights worldwide including Europe, US and Japan

Core Patent covers concept of using SAW sensors for non-contact measurement

§ Over 40 new Patent Applications filed by Transense

SAW sensor design and packaging

Interrogation electronics including ASIC

Antennas and Couplers for RF transmission

Intellectual Property

Transense Technologies plc – 26/01/05 – Issue 26

Existing Licences

SmarTire Sep 1999 Appl On-wheel tyre pressure

3DMl Dec 2000 App In-wheel tyre pressure

Michelin Jun ’01 Sept ‘04 Appl In-tyre tyre pressure

TT electronics Oct 2001 Appl Steering torque transducer

Temex Microsonics Aug 2002 Manu SAW devices

TAI-SAW Technology Oct 2002 Manu SAW devices

Melexis Nov 2003 Manu ASIC

Stack Oct ‘04 Appl / Manu Special Applications Motorsport

Honeywell Apr ’02 Nov ‘04 Appl / Manu Pressure & Torque sensors &

Interrogation electronics.

Licensee Date Type Description

Transense Technologies plc – 26/01/05 – Issue 27

Transense has licences in place with all parts of the supplier chain

Transense Licence Chain

OEMs & Dealers

ManufacturingComponents

ManufacturingIntegration

ApplicationsLicensees

Technology

Technology

Technology

Transense Technologies plc – 26/01/05 – Issue 28

Surface Acoustic Wave Sensors

§ In 1887, Lord Rayleigh discovered the SAW propagation mode and in a classic paper predicted the wave properties.

§ SAW devices are low cost products, manufactured in large volume approx – 4.5 million / day - mainly for mobile telephones and television.

§ SAW sensors typically operate between 100MHz and 1GHz

§ SAW resonant sensors can act as strain gauges with their natural frequency dependent on strain and temperature

§ Transense SAW pressure and Torque sensors utilise standard manufacturing equipment and production techniques.

SURFACE

SAW SUBSTRATE

STRAIN ENERGY

DE

PT

H

YZ

λ

λ

Transense Technologies plc – 26/01/05 – Issue 29

§ Inter-digitaltransducer

§ Reflecting array of metal strips:number ~ 200period λ/2 ~ 2 micron

§ Single crystal quartzsubstrate

§ Al metallisation layer thickness ~0.1 micron

SAW – single port resonator

Transense Technologies plc – 26/01/05 – Issue 210

Interrogation Method – typical resonator response

Oscilloscope waveform Sampling strategy

Transense Technologies plc – 26/01/05 – Issue 211

Tyre Pressure / Temperature Sensor

QuartzSubstrate P SAW

T1 SAW T2 SAW

Dimple positionLedges

Separation of variables

• All 3 SAW resonators respond to temperature

• Only the P SAW responds to pressureThus ∆F (P – T1) is proportional to pressure

• Single crystal quartz is anisotropic, so thatT1 and T2 respond differently to temperatureAnd ∆F (T1 – T2) is proportional to temperature

Transense Technologies plc – 26/01/05 – Issue 212

Simulation of TPMS Sensor under Pressure

Transense Technologies plc – 26/01/05 – Issue 213

Tyre Pressure – SAW sensors

Sensors may be:

§ Attached to Wheel or back of valve

§ Embedded in Wheel

§ Embedded/attached to Tyre

Transense SAW systems measure tyre pressure with temperature compensation

Transense Technologies plc – 26/01/05 – Issue 214

Tyre Pressure – Embedded SAW Sensors

Snap-In rubber valve for cars

Screw-in metal valve for cars

Long reach truck valve

Transense Technologies plc – 26/01/05 – Issue 215

TPMS System

4 passenger car sensors

Interrogation Electronicsincorporating:

Custom RF ASIC and DSP

Transense Technologies plc – 26/01/05 – Issue 216

Tyre Pressure – sensor comparisons

TPMS Sensor - 2 gm mass (12mm x 2.5mm)

Competition – typically 30gm mass

In Motorsport, the typical mass of competitive systems necessitates a counterweight.

The requirement for continuous data in Motorsport severely restricts battery life.

Transense Technologies plc – 26/01/05 – Issue 217

Competitive Technologies in TPMS

§ ABS-Indirect measurement: Low cost but many drawbacks, e.g bendy roads,slippery road surfaces, more than one tyre deflating at once. In 2003 this method effectively rejected in a US Court of Appeals judgement for TREAD Act purposes.

§ Piezo-resistive or Capacitive, battery powered: current technology, relatively expensive. Requirement for 10 year battery life and disposal are real limiting issues.

§ Piezo-resistive or Capacitive, inductively powered (125 kHz): one or two systems are being launched, somewhat bulky, cost still an issue.

§ Resonant Crystal + Capacitive Sensor (modulated 2.45 GHz carrier), batteryless:one system near market, relatively complex, cost?

§ Giant Magnetic Impedance, batteryless: one system known to be in development, temperature stability may be an issue, cost?

Transense Technologies plc – 26/01/05 – Issue 218

TPMS Sensor Parameters

0.05m to 0.5m0.05m to 0.5mRead Range (typical)

0.5mW to 10mW0.5mW to 10mWInterrogation power

0.1Hz to 10Hz0.1Hz to 10HzUpdate rate

<1.5°C<1.5°CTemperature - combined error

<0.03bar (0.5psi)<0.1bar (1.5psi)Pressure - combined error

0.01bar (0.15psi)0.03 bar (0.5psi)Resolution

-40°C to +125°C-40°C to +125°C Operating temperature range

0 – 3bar (45psi)0 – 10bar (150psi)

Transense Technologies plc – 26/01/05 – Issue 219

Tyre Pressure – TPMS Applications

Transense has ongoing advanced TPMS programs in the following sectors:

Truck & Bus

Passenger Car

Motorsport – Formula 1, GT Endurance, Motorcycle

Aircraft

Military & Up-armoured

Run Flat Systems

Transense Technologies plc – 26/01/05 – Issue 220

Torque Sensors – other applications

Transense has ongoing TORQUE programs for the following applications:

Engine Management

Automatic Transmission

4 Wheel Drive Torque Splitters

Electric Power Steering (EPAS)

Agricultural Power Take Off

Transense Technologies plc – 26/01/05 – Issue 221

SAW Technology Summary

Sensor: Surface Acoustic Wave (SAW) single port resonator

§ SAWs sense pressure, temperature and torque by detecting minute strain changes

§ Wireless operation enables continuous interrogation and display

§ SAW sensors operate at high frequency - typically 433MHz

§ SAW offers high bandwidth and high resolution measurement

§ SAW Interrogation using digital techniques with direct interface with customer electronics

§ SAW devices are small, light weight, robust, environmentally friendly (no batteries) and offer low costs in volume manufacture

§ Applications include tyre pressure, EPAS and driveline torque measurement

Double SAW

Torque Device

Triple SAW

Pressure Device

Transense Technologies plc – 26/01/05 – Issue 222

For further information please contact:

TransenseTechnologies plc

66 Heyford Park, Upper Heyford, Bicester, Oxon. OX25 5HD. UKTel: +44 (0) 1869 238380 Fax: +44 (0) 1869 238381

Website: www.transense.co.uk