Loya Chandreshkumar, Joshi Pranav, Chaudhari Hemraj, Prof. Gayatri Bokade / InternationalJournal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.345-348345 | P a g eITire Pressure Monitoring System And Fuel Leak DetectionLoya Chandreshkumar,1Joshi Pranav,2Chaudhari Hemraj,3Prof. GayatriBokade4Department of electronics & telecommunicationNutan Maharashtra Institute of Engineering & Technology University Of Pune Pune, IndiaAbstractImproper tire pressure & temperatureis a safety issue that is often overlooked orignored. A drop in tire pressure by just a fewpounds per square inch (psi) can result in thereduction of fuel mileage, tire life, safety, andvehicle performance. This paper presents a kindof Tire pressure monitoring system (TPMS) withfuel leak detection, introduces the main chipsand the principle of system. Key issue of systemare discussed: Installation of master and slavesection, Wireless signal transmission, Low powerstrategies. To address these problems, anautomated system that will alleviate the need foractively maintaining tire pressure was designed.Keywords—tire pressure, TPMS temperature,wireless communication,I. INTRODUCTIONN a super highway, tire fault is very hardto prevent and a severe problem to drivers. It is oneof main reasons of the sudden traffic accidents.Statistics shows that the number of the trafficaccidents happened owing to tire break is about70% of the whole. In the India, the proportion isnearly up to 37% .major accidents also happendue to gas leakage.Researches indicates that the key measureof avoiding tire-break is to keep the tire pressurenear to its standard value and discover tire pressurerelease in time. Thus, tire pressure monitoringsystem (TPMS) has been drawing attention ofmany researchers and engineers.The majority of automobile drivers do notadequately maintain their tire pressure, even thoughtire loses approximately one to two pounds persquare inch (PSI) of air pressure a month.Underinflated tires cause a greater contact surfacearea with the road, resulting in higher frictionbetween the road and tire. This significantlydecreases tire life and fuel economy. According toDoran Manufacturing, when tires are 20%underinflated, tire life and fuel economy can bereduced by 30% and 3% respectively . Vehiclehandling characteristics are also adversely affecteddue to low tire pressures. Stopping distancesincrease and the driver experiences a loss ofsteering precision and cornering stability. With allthese undesirable effects, proper tire pressureshould be of greater concern. The NationalHighway Traffic Safety Administration (NHTSA)statistics show that 660 fatalities and 33,000injuries occur every year as a result of low-tirepressure-related crashes .II. TYPES OF TPMSA. Direct TPMSTPMSs are classified into two categories,namely, direct and indirect. In direct TPMSs, thepressure drop is calculated based on actual pressuremeasurements through sensors. In contrast,measurements such as wheel speed are used inindirect TPMSs. A direct TPMS can inform thedriver about pressure deviations as low as ±0.1 bar,that is, ±1.45 psi. The following sections explainthese types of TPMS in detail. Tire inflation isidentified through pressure sensors in a directTPMS. A low-cost, direct TPMS consists of asensor fitted on the tire valve stem, which changesits color when the pressure drops. This sensor haslow accuracy and cannot communicate data to thedriver. Alternatively, a more sophisticated versionof a direct TPMS consists of sensors, radiofrequency transmitters and receiver, and a warningsystem. Each tire’s pressure is measured andtransmitted through its sensor and transmitter. Thetransmitted signals are received, decoded, andprocessed by the receiver to trigger the warningsystem through an alarm lamp, audible alarm,voice, or pressure display. The proposed systemuses the direct tpms scheme for our system.B. Indirect TPMSAn indirect TPMS predicts tire pressuredrop using an observer coded in software and thusdoes not require tire pressure sensors. Availableindirect TPMSs are based on wheel speedmeasurements. When the tire pressure decreases,the vehicle’s weight causes the tire’s diameter todecrease, which causes the tire to rotate at adifferent rate than when it is at full pressure.Therefore, only software is needed to implement anindirect TPMS. However, several shortcomings areassociated with indirect TPMS. First, the systemdoes not provide the actual pressure of each tire andworks only when the vehicle is in motion. It warnsthe driver only when the pressure drop is more than25% and, moreover, may generate false warningswhen the vehicle is moving on a curved road orduring tire slip on snowy roads.
Loya Chandreshkumar, Joshi Pranav, Chaudhari Hemraj, Prof. Gayatri Bokade / InternationalJournal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.345-348346 | P a g eIII. SYSTEM ARCHITECTUREThe general scheme of TPMS and fuelleak detection is shown in figure1: Sensor, MCU,RF Transmitter, RF Receiver , Sensor, MCU, LCD.From this configuration, we can see that the generalconfiguration can be divided into two parts first oneis Master and second is slave.Figure 1: Block diagram of systemIn master section two sensors and receiverare connected to LCD consisting of microcontrollerunit. The slave section consists of two sensors andtransmission module. The sensors are connected totransmission module consisting of amicrocontroller unit.A. SensorIn the presented system we are using threetypes of sensor.1) Pressure sensor: We choose a MPXH6400Aprovided by FREESCALE as a pressure sensor.It is a absolute voltage output sensor whichworks for pressure range 20 to 400 Kpa.2) Temperature sensor: The temperature sensorof range -55° to +150°C used is LM35 byNational Instrument.3) Gas sensor: The gas sensor MQ6 is used todetect the gas leakage after 200ppm of LPG inair.B. Radio frequency transmitter and receiverIn the system, how to effectively transmitand receive the wireless radio frequency signal is akey technique and this costs most of power. Whenchoosing a wireless radio frequency module. Wemust consider power consumption, bandwidth,speed and capability as well. So we choose CC2500as the radio frequency module which is provided byTEXAS INSTRUMENTS. It has large ranges offrequency bandwidth, operation voltage andtemperature, high speed data transreceivecapability. The module also has many advantagessuch as low power consumption, high accuracy andwide range of communication up to 30 meters. Itsupports various modulation formats such as OOK,2-FSK, GFSK, and MSK and has a configurabledata rate from 1.2 to 500 kBauds.C. Circuit sketch map and working principleThe sketch map of transmission circuit isshown in figure.2: in which working principle oftransmission module is illustrated. In normalworking state after power on both sensors sendsdata to MCU in analog form. The MCU’s inbuiltADC converts the analog data in digital form. Thenthe data is given to transmission module CC2500and so the data is spread out in the form of RFwaves by using modulation.Figure 2: sketch map of transmission circuitThe sketch map of master circuit is shownin figure3. The working principle of receivingmodule is illustrated. After receiving the data fromslave circuit and demodulating it the receivingmodule sends data to AVR. AVR is alsoaccompanied with two sensors. The AVR gathersall the data and compare it with preset values.CC2500AVRATMega16LM35MPXH6400CC2500LM35MQ6AVRATMega16LCD
Loya Chandreshkumar, Joshi Pranav, Chaudhari Hemraj, Prof. Gayatri Bokade / InternationalJournal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.345-348347 | P a g eFigure 3: sketch map of master circuitThe system displays 4 pressure and temperaturevalues on LCD circularly according to a certaininterval, then judge whether temperature value orpressure value is normal so as to decide whetherstart warning function or not. The warning functionincludes pressure-too-high warning, pressure-too-low warning, tire-flat warning and temperature-too-high warning with the current values of pressureand temperature of the respective tire. When sensordetects the gas leakage, microcontroller switchesthe buzzer and if the gas leakage goes above acertain limit then power window will automaticallyopens and gas leakage warning is displayed.IV. KEY ISSUESA. Installation of the Master and Slave section1) Slave section: Slave circuit is fitted on the ring& pressure sensor will be connected to the valve asshown in figure.4.Figure 4: Slave section installationThere is some modification on the ring & tubeis required. The tube which is required should havetwo valves & in ring there is only one more hole isrequired. In this system the breaking possibilities isvery low & the tube changing will not waste thecircuit. The slave circuit is water-proofed.2) Master section : The master circuit is fittednearer to the dashboard as shown in figure 5.1.Figure 5.1: Master section installationThe display is below to the steering so it willeasily draw the attention of driver as shown infigure 5.2.Figure.5.2 LCD placementThe Gas leak detector would be nearer to gastank so it is possible to detect faster. The enginetemperature sensor should connect on the engineheat shield.B. Wireless signal transmissionA key technique in TPMS is the stabilityand reliability of the wireless signal transmission,especially in super highway. Many factors, such asdisadvantageous working environment in highspeed and signal-shielding, may producedisturbances to signals. Besides, when we usehandset and electronic devices in the car, signalswill interfere with each other, and the stability ofthe signal transmission will also be affected. Thus,when choosing wireless signal transmissionmodule, we choose the chips CC2500. In themeantime, in order to improve the disturbance-rejecting capability, we choose the Manchestercoding, the FSK (frequency-shift keying) mode.Further it has high sensitivity (type -104dBm) &also programmable output power -20dBm~1dBm.These measures can ensure the stability andreliability of the wireless signal transmission.C. Low power strategiesSince the battery on the transmissionmodule should work for 10 to 12 months,decreasing power consumption is a very importanttask for the system. Thus, only if we make the