1、TPMS(轮胎压力监视系统)尹智海2008.4TPMS: The Tire Pressure Monitoring SystemTire pressure nominal pressure valid for cold tires gas-law:p * V = n * R * T Advantages:conserve fuel and long life expectancyTire failures natural pressure loss punctures from screwsTire pressure warning algorithmInputsTire pressureTi
2、re temperatureWarning algorithmPlausibility checksThreshold supervisionTemperature compensationLeak rate identificationOptional inputsVehicle loadVehicle speedAmbient temperatureAmbient pressureOutputsWarningAlertDriver informationFor internal use only!160kPA200kPa200kPa200kPa前装市场后装市场TPMS法律规定2005年4月
3、8号NHTSA(美国国家高速公路交通安全管理局)规定：1）轻型汽车安装率2005.10.5前安装率20% (第一阶段)2006.9.1前安装率70% (第二阶段)2007.9.1前安装率100%新车出厂注册登记之后180天内TPMS安装到位.2）市场端要求(2004.9.16)轻型车前端市场：2004.9.16-2005.4.8间生产的车必须在2007.9.1前TPMS 完成安装。对汽车厂商而言的后端市场：在第一阶段生产的汽车必须部分或全部符合规定要求。TPMS系统组成分类1)基于ABS/ESP系统：+ use of existing wires（使用ABS/ESP总线传输）+ 一个中央处理单
4、元/无需外部其他电路-不能实现NHTSA规定25%的测量精度2) 主动式直接胎压检测系统(Battery-based)：主流市场+ ISM-Bands (315/434 MHz) (2.4 GHz, 5.8 GHz)+ 仅需要RF TX (Transmitter), 使用RKE系统中RX(Receiver)+ 需要管理轮胎转速+ 系统独立于轮胎厂商- lifetime受电池使用寿命决定(5-10年)3)被动式直接胎压检测系统(Battery-less)+ 无源Transponder, Energy Harvesting(能源自感应)+ 使用周期无时间限制-每个轮胎附件转速感应器-与轮胎厂商需建
5、立通用数据协议TPMS系统主要要求Lifetime 10年应用温度范围-40C-+125C高介质兼容性可靠的测量精度高速行驶(240km/h)的信号接收灵敏度TPMS市场预测TPMS系统发展趋势当前直接式主动TPMS系统占据市场主流欧洲和美国市场TPMS有各自的特点成本依然是TPMS市场推广的一个主要瓶颈TPMS的发展趋向于“智能轮胎”以及无源式系统Market stimuliUSA all new light vehicles from 2007, Sep 1Europe / Japan safety and comfort featureForces driving TPMSTPMS pr
6、oduct roadmapBlind“ fulfilling of regulations (NHTSA, Run-Flat) at lowest priceIncreased Safety by detecting pressure loss and preventing from accidentsIncreased Safety by optimizing active safety (VSC)Fancy feature- end customer is spending moneyReduced fuel consumption -pollution(CO2)Warranty issu
7、es (logging distance driving at low pressure or high speed)Indirect systemsFL .RRrFL.rRR= _ = _FR .RLrFR.rRLDirect TPMS - Non Auto LocalizationDirect system with LF-based LocalizationRKE ECUDirect system with LF-based LocalizationFord (L,SV)GM (SV)Toyota (TRW)Hyundai (L)Example of LOW END Indictor D
8、isplay(Typical of NAFTA Vehicles)Distinguishing Characteristics: Simple indicator light for deflated tire(s) Possibly reduced battery lifeTPMS System I: LOW-END TPMS SystemDCX (SV)Honda (TRW)Hyundai (L,TRW)Toyota (TRW)Example of MEDIUM LEVEL Indictor Display(DaimlerChrysler Truck/SUV)Distinguishing
9、Characteristics: Indicators for deflated tire position(s) No display of current P valuesTPMS System II: MEDIUM-LEVEL TPMS SystemMY09 DCX (Schrader)GM (SV, Schrader)DCX (SV)Honda (TRW)Hyundai (L,TRW)Example of HIGH END Indictor Display(Acura RL)Distinguishing Characteristics: Real-time data display a
10、vailable to driver Frequent RF updates (at least 1/minute) Pressure-on-Demand possible w/LF Tie-in to Vehicle Dynamics possible Some form of localization requiredTPMS System III: HIGH-END TPMS SystemMY09 DCX (Schrader)GM (SV, Schrader)Application Features versus Product FeaturesDash board displaySin
11、gle Warning LightOne warning light per wheelNumerical pressure per wheelno localizationLocalization in warning mode only(post-alarm)Continuous localization during driving(prior to alarm)Localization by indirect techniques2-axis-g auto-localizationLF based auto-localizationPermanent localization even
12、 in park mode(prior to alarm)Localization Feature Localization TechniqueMeasurement point in timeAfter 20 minutes latestImmediately after vehicle speed 30km/hAnytime (even during parking)Activation TechniqueIn-wheel accelerometerLF triggerNo activation (permanent send every 520 minutes)TPMStechnique
13、indirectdirect200kPa200kPa 160kPa200kPalowendmidendhigh endTyre Pressure Monitoring ModuleTPM SensorSystem ComponentsTPMS ModulPressure SensorTemperature SensorAcceleration SensorSupply Volt. SensorSensor DiePressureSensorAccelerationSensorIntegration of sensors and microchipASICSensor Die:Pressure Sensor +AccelerationSensorASICExample for a typical battery based moduleBATTERYTPM SENSORSP30(T) Key FeaturesSP30SP30PADCASICALF InterfaceRISC PCH7970 C128B EEPROM128B RAMTV4kB (E)ROMTimerDig. PeripheralsSensor die
