TPMS(轮胎压力监视系统)尹智海 2008.4TPMS: The Tire Pressure Monitoring SystemTire pressurenominal pressure valid for cold tires gas-law:p*V=n*R*TAdvantages: conserve fuel and long life expectancyTire failuresnatural pressure losspunctures from screwsTire pressure warning algorithmOptional inputsVehicle load Vehicle speed Ambient temperature Ambient pressureInputsTire pressure Tire temperatureWarning algorithm OutputsPlausibility checks Threshold supervision Temperature compensation Leak rate identification Warning AlertFor internal use only!Driver information前装市场200kPa160kPA200kPa200kPa后装市场TPMS法律规定 2005年4月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 - - 与轮胎厂商需建立通用数据协议TPMS系统主要要求 ■ Lifetime >10年 ■ 应用温度范围-40°C--+125°C ■ 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 stimuliEurope / Japan safety and comfort featureUSA all new light vehicles from 2007, Sep 1Forces driving TPMSTPMS product roadmap …Blind“fulfilling of regulations (NHTSA, Run-Flat) at lowest price Increased Safety by detecting pressure loss and preventing from accidents Increased Safety by optimizing active safety (VSC)Fancy feature-end customer is spending money Reduced fuel consumption -pollution(CO 2)Warranty issues (logging distance driving at low pressure or high speed)`RKE ECUDirect system with LF-based LocalizationTPMS System I: LOW-END TPMS SystemDistinguishing Characteristics: • Simple indicator light for deflated tire(s) • Possibly reduced battery lifeExample of LOW END Indictor Display (Typical of NAFTA Vehicles)Ford (L,SV) GM (SV) Toyota (TRW) Hyundai (L)TPMS System II: MEDIUM-LEVEL TPMS SystemDistinguishing Characteristics: • Indicators for deflated tire position(s) • No display of current P valuesExample of MEDIUM LEVEL Indictor Display (DaimlerChrysler Truck/SUV)DCX (SV) Honda (TRW) Hyundai (L,TRW) Toyota (TRW) MY09 DCX (Schrader)GM (SV, Schrader)TPMS System III: HIGH-END TPMS SystemDistinguishing Characteristics: • Real-time data display available 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 requiredExample of HIGH END Indictor Display (Acura RL)DCX (SV) Honda (TRW) Hyundai (L,TRW) MY09 DCX (Schrader)GM (SV, Schrader)Application Features versus Product FeaturesDash board display TPMS technique Activation Technique Measurement point in timeLocalization Feature Single Warning LightLocalization Techniquelow endno localization indirectNo activation (permanent send every 5…20 minutes)After 20 minutes latestmid endOne warning light per wheelLocalization in warning mode only (post-alarm)Localization by indirect techniques directhigh endNumerical pressure per wheelContinuous localization during driving (prior to alarm)2-axis-g autolocalizatio nIn-wheel accelerome ter LF based autolocalizati onImmediately after vehicle speed >30km/h200kPa 200kPa160kPa 200kPaPermanent localization even in park mode (prior to alarm)LF triggerAnytime (even during parking)Tyre Pressure Monitoring ModuleTPM SensorSystem Components TPMS ModulPressure Sensor Temperature Sensor Acceleration Sensor Supply Volt. SensorSensor DieAcceleration SensorPressure SensorIntegration of sensors and microchipSensor Die:Pressure Sensor + Acceleration SensorASICASICExample for a typical battery based moduleBATTERYTPM SENSORSP30(T) Key FeaturesSP30 SP30 Sensor die RISC PCH7970 µC ADC PASIC128B RAM 128B EEPROMAT V4kB (E)ROM Timer Dig. Peripherals LF InterfaceTire Pressure Monitoring System (TPMS)SP30 SP30P ADC Signal Conditioning Compensation.ASICTDK5100TX_Data RF TxµC A LF InterfaceBenefit of Bulk Micro Machining Technology: Robustness & Media CompatibilityA triple stack sensor solution provides the media compatibility required for automotive applications.• Pressure Cook • Auto transmission fluid • Salt fog • Degreaser / Car waxes • Sea water • Keystones / Chlorine bleach • Dust • Anti-burst spray • Boiling water • Temperature Shock • Gas fumes • Diesel fumes • Brake fluid • Engine coolant • Tire mounting soap + mounting grease • Alloy wheel cleaner • Alcohol based cleaner • Vinyl plasticizers / Hand cleaner • Engine oil / Unleaded gasoline • Power steering fluidConfidentialTire Localization with LF Trigger AntennasLF & RF CCU/CRU LF & RF LF LF LF & RF LF & RF LF LFTire Localization: Signal Propagation – Decentral RF CRU(LF) & RF CCU/CRU (LF) & RF (LF) & RF (LF) & RFTPMS系统构成： 发射器(transmitter)： 由压力传感器、MCU、射频发射芯片、电池、和天线组成。