TPM Article: 50%+ Growth through 2004!
From ZDNet this article on the sensor market for Temperature and Pressure Monitors for motor vehicles...
Later...Klingerg
FROM THE EDITOR: SENSORS FOR TIRE MONITORING HAVE KEY GROWTH OPPORTUNITIES. 12/01/00
Sensor Business Digest
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SBD notes that sensors for continuously monitoring vehicle tire pressure and temperature have keen opportunities over the near-term in both OEM an after market applications, driven by vital driver safety concerns, as well as by fuel economy and environmental issues. To optimally exploit the market for sensors in automotive tire pressure monitoring systems (TPMS), sensor manufacturers should ensure that they will be capable of efficiently producing TPMS sensors in high volumes with high yields and decent margins.
Low tire pressure can lead to significant tire and road ware, and results in lower mileage and greater expenditures for gasoline. Run-flat (or extended mobility) tires, which are designed to survive a tire puncture long enough for the car to be driven to a convenient location for repair or replacement, require a tire pressure monitoring system. Such tires, which can free up trunk space by eliminating the need for a spare tire, could become more prevalent in the future.
Opportunities in the U.S. for sensors that provide real-time information about vehicle tire pressure and temperature have been spurred by the recall of 6.5 million Firestone tires in August. The tires have been linked to 119 deaths in the U.S., involving rollover accidents mainly on Ford Explorer SUVs. The performance issues with respect to the recalled tires (particularly the ATXs) have been attributed to such factors as tire design, tire components, and the interaction of the tire with the vehicle. Heat generated in the tire appears to be a key factor affecting its performance.
As noted in The Wall Street Journal (November 7, 2000), a tire expert has stated that the treads on certain of the recalled tires are too wide and the corners are too squared off. Due to the wider tread, more rubber comes in contact with the pavement, which tends to heat up the tire. If the corners are squared off, there is greater stress (and heat) on the edges of the steel belts. Heat accelerates the breakdown of the bond between the steel belts.
Along with scrutinizing the design, Firestone has been focusing on whether the material between the two steel belts can resist the heat generated by the tire during normal operation without losing strength. Tread separations tend to occur in the interbelt area, which includes the steel cords that are made into two belts coated with rubber and a strip of rubber between the edges of the two belts.
Firestone has determined that a preponderance of the claims on the recalled tires involve the left rear tire, engendering questions about how a vehicle's design puts greater load or stress on that tire. Moreover, Firestone has found that lower tire inflation generated excessive heat; and they have recommended that the tires should be inflated to 30 psi.
To strengthen the U.S.'s motor vehicle safety laws and ensure more timely information about potential safety defects, H.R. 5164, the Transportation Recall Enhancement, Accountability, and Documentation (TREAD) Act was signed into law on November 1st. Section 13 states: "Not later than 1 year after the date of the enactment of this Act, the Secretary of Transportation shall complete a rule making for a regulation to require a warning system in new motor vehicles to indicate to the operator when a tire is significantly under inflated. Such requirement shall become effective not later than two years after the date of the completion of such rule making."
H.R. 5164, essentially, asks the National Highway Traffic Safety Administration (NHTSA) to, within one year of the Act's passage, set a standard for a dashboard warning about tire inflation levels. Within three years of the enactment of the Act, NHTSA must implement the low tire pressure warning rule.
SensoNor asa (Horten, Norway, ++47-33-03-5000/San Francisco, CA, 415-986-6059)(www.sensonor.com)--which is publicly traded on the Oslo Stock Exchange, and manufactures silicon micromachined MEMS (microeelctromechanical sysstems) accelerometers and pressure sensors for automotive, aerospace, and medical applications--is finding burgeoning opportunities for its tire pressure monitoring sensors.
Hans R. Petersen, SensoNor's manager of business development for North America expects tire pressure monitoring sensors to eventually become as ubiquitous as air bag accelerometers on vehicles. A tire pressure monitoring system uses four sensors, one in each tire.
SensoNor established a sales and service office in the U.S. in 1998 to exploit key markets for their sensors, especially the North American market for tire pressure monitoring systems. During calendar 2001, SensoNor expects to produce tire pressure sensors in high volumes (on the order of millions of units); and their tire pressure sensors are expected to begin to appear in North American vehicles during calendar 2001. SensoNor--which is a key provider of micromachined accelerometers with integrated signal conditioning ASICs, and has reportedly suppliied on the order of 40 million crash sensors for vehicle air bag systems since 1987--has the capability to produce about 30 million pressure sensors annually.
SensoNor began work on tire pressure sensors about five years ago. The initial proof-of-concept systems were discrete designs based on aerospace-quality sensors. In collaboration with Doduco, SensoNor designed a low-cost cost pressure sensor with high media compatibility. Such sensors became part of SensoNor's SP10 family of tire pressure monitoring sensors, which are able to survive in the tire monitoring environment and include a customized ASIC and a temperature sensor. Doduco was subsequently acquired by Beru (Ludwigsburg, Germany), a tier 1 supplier of tire pressure monitoring systems that use SensoNor's sensors.
SensoNor's tire pressure monitoring sensor went into production in 1997, and since that time millions of units have been produced. In 1997, SensoNor's tire pressure sensors were introduced in BMW European 7-series cars; and in 1998 such sensors were adapted to the BMW 5-series. SensoNor's patented feed-through method of simultaneously forming the sealed vacuum cavity and the electrical connections passing the anodic bonding area provides a hermetically sealed sensor. There has not been a single field failure during the three years that the German programs have been underway.
SensoNor has been informed that their tire pressure sensors will be available in the BMW 3-series vehicles in 2001. During calendar 2001, SensoNor's tire pressure sensors will also be implemented in tire pressure monitoring systems on Volkswagen, Mercedes, Porsche, and Audi vehicles. In Japan, their tire pressure sensors will be available on some Toyota 2001 models. An Italian car manufacturer is expected to begin releasing vehicles in early 2001 that incorporate SensoNor's tire pressure sensor chip.
Under an agreement with Siemens Automotive S.A., SensoNor will develop and produce tire pressure sensors for Siemens' system, which will be delivered as standard equipment on several European mid-size vehicles, beginning in MY2003. SensoNor will begin production in early 2002. The value of the agreement was initially estimated at NOK 200 million (about $21.4 million at the current exchange rate) over four years. With demand for the systems expected to increase, the value of the agreement could exceed NOK 400 million (about $42.8 million) over four years.
SenosoNor developed its ASIS (application specific integrated sensor) for use in SmarTire Systems' (Richmond, BC, Canada) next-generation SmarTire(tm) monitoring system for the after-market and in TRW Automotive Electronics' (Farmington Hills, MI) TireWatch(tm) system for OEMs. Such tire pressure monitoring systems were developed under a strategic alliance announced in 1998, whereby TRW has a license to use SmarTire technology to serve original equipment manufacturers in passenger car and truck markets. SmarTire has rights to the after-market (including dealer-installed options and special edition foreign-made vehicles).
The SmarTire monitoring system, equipped with SensoNor's sensors, is in the final stages of testing and is not yet available in the marketplace. The system, which provides an early warning of a potential tire problem, uses wheel mounted sensor/transmitters inside each tire to monitor contained air pressure and temperature. Data is transmitted via radio frequency to a receiver located near the driver.
TRW's TireWatch system, which will use SensoNor's sensors, is expected to be in production for automotive OEMs, beginning around the first quarter of next year.
Last September, TRW and Michelin announced an agreement to spearhead advanced tire pressure monitoring technology and a new generation of tire and wheel systems. Treating the tire, wheel, and sensor as a single system will allow for optimizing the entire package for performance, reliability, weight, and cost. Michelin's special predictive algorithms will use vehicle operating condition information and TRW's tire condition data to alert drivers to marginal operating conditions. The technology will identify which tire has potential problems.
TRW and Michelin will work on developing advanced warning strategies. Moreover, they will develop improved tire pressure monitoring systems for Michelin's Pax system (a tire/wheel assembly that prevents the tire from coming off the wheel when it goes flat) and conventional radial tires.
In October at the Convergence 2000 International Congress on Transportation Electronics, TRW displayed its tire pressure monitoring technology and Michelin's PAX system technology. The TireWatch system uses a sensor mounted on the tire valve stem to monitor air pressure and temperature inside the tire. Information is transmitted via radio signal to a control unit in the vehicle, which provides warning messages to a driver information display.
SensoNor notes that its tire pressure sensor technology offers a proven, reliable solution for tire pressure monitoring. Moreover, they note that an alternative approach--which uses ABS wheel speed sensors to compare the effective rolling radius of one tire to that of other tires in order to deetermine tire deflation--cannot detect temperature build-up in the tire and is incompatible with run-flat or low-profile tires.
Over the longer-term, surface acoustic wave (SAW) technology may have potential for offering advantages in tire pressure monitoring. The SAW system would not require battery power (thereby eliminating any environmental issues pertaining to battery disposal). It transmits data without the need for additional electronics inside the tire; and is capable of monitoring varied tire performance characteristics (not just pressure and temperature). The size advantage of having the sensor and transmitter in a single device would facilitate packaging and mounting options. SmarTire Systems has obtained rights to Transense Technologies' (Bicester, Oxfordshire, England) SAW technology for use in future tire monitoring systems for the automotive industry.
The triple-stack sensor element used in SensoNor's pressure sensors consists of single-crystal silicon sandwiched between two glass layers. When exposed to external pressure, the four piezoresistors forming a Wheatstone bridge sense mechanical stress in the silicon diaphragm. The resistance value will change according to the piezoresistive effect in doped silicon. The sensor's sealed vacuum cavity is made by anodically bonding (joining) the borosilicate glass wafer to the silicon wafer.
By using diffused and buried conductors, the piezoresistors and interconnection leads are placed on the same side of the sensor element as the vacuum cavity. The sensor element offers excellent media compatibility, since the pressure inlet port is toward the backside of the silicon diaphragm, and the front side--containing metal conductors, piezoresistors, and the electrical interconnections that are more sensitive to corrosion and mooisture--is protected inside the sealed vacuum cavity.
In addition to the sensor chip, the SP10 tire pressure monitoring sensor includes a VLSI ASIC with a digital core design that ensures high accuracy over a temperature range of -40[degree sign] to +125[degree sign]C, and provides continuous status verification during operation and intelligent calibration routines. Designed to be configured into a battery-powered wheel module, the SP10 is able to handle input from a roll switch to detect if the wheel is rolling. The pressure voltage signal, together with the voltage signal from the proportional-to-ambient temperature sensor (PTAT), is converted to a digital signal by an 11-bit charge-balancing A/D converter. The digital core uses fixed algorithms for calculating the accurate pressure over the temperature and pressure ranges.
Next year, SensoNor plans to ship a version of the SP10 that uses even less power and has enhanced accuracy. In the future, SensoNor plans to integrate the microcontroller into the tire pressure sensor chip to provide a readily programmable sensor chip, affording greater flexibility for the designer of the tire pressure monitoring system. Further down the road, SensoNor plans to integrate the RF transmitter into the pressure sensor chip with an on-board microcontroller.
The automotive market for on-board tire pressure sensing systems that use pressure sensors totaled $38 million in 1999 and is projected to reach $291 million in 2004, representing a compound annual growth rate of about 50.3%, according to Strategy Analytics (Boston, MA, 781-235-6550). Unit volume for the automotive market for tire pressure sensing systems totaled 541,000 in 1999 and is predicted to reach 5,500,000 in 2004, representing a compound annual growth rate of about 59%. One tire pressure sensor is used in each tire, with some automakers using a sensor for the spare tire.
From January-October 2000, 7,062,063 cars and 7,704,717 light trucks were produced in North America, according to Ward's AutoInfoBank (Southfield, MI, 248-357-0800).
Sincerely,
Peter Adrian, Editor
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