A tire pressure monitoring system ( TPMS ) is an electronic system designed to monitor air pressure inside pneumatic tires in different types of vehicles. TPMS reports real-time tire pressure information to the driver of the vehicle, either through a meter, a pictogram screen, or a simple low-pressure warning light. TPMS can be divided into two different types - direct (dTPMS) and indirect (iTPMS). TPMS is provided both at the OEM (factory) level and aftermarket solutions. Targets of the TPMS are to avoid traffic accidents, poor fuel economy, and increased tire wear because tires are under pressure through early recognition of dangerous tire conditions.
Video Tire-pressure monitoring system
History
Initial implementation
Due to the influence of tire pressure on vehicle safety and efficiency, tire pressure monitoring (TPM) was first adopted by the European market as an optional feature for luxury passenger vehicles in the 1980s. The first passenger vehicle to adopt TPM was Porsche 959 in 1986, using a hollow spoke wheel system developed by PSK. In 1996 Renault used the Michelin PAX system for Scenic and in 1999 PSA Peugeot CitroÃÆ'Â nn decided to adopt TPM as a standard feature on the Peugeot 607. The next year (2000), Renault launched Laguna II, the first high volume medium-sized passenger vehicle in world to be equipped with TPM as a standard feature. In the United States, TPM was introduced by General Motors for the 1991 model for the Corvette along with Goodyear run-flat tires. The system uses sensors on wheels and display drivers that can show tire pressure on any wheel, plus warnings for high and low pressures. It has been standard on the Corvette ever since.
Firestone Withdrawal and legal mandate
Firestone's legacy in the late 1990s (linked to over 100 deaths due to rollovers after tire separation), prompted the United States Congress to pass the TREAD Act. The law mandates the use of appropriate TPMS technology in all light motor vehicles (under 10,000 pounds), to assist drivers who are wary of events below inflation. This action affected all light motor vehicles sold after September 1, 2007. Phase-in started in October 2005 by 20%, and reached 100% for models produced after September 2007. In the United States, in 2008 and the EU, as of November 1 2012, all new passenger car models (M1) released should be equipped with TPMS. From 1 November 2014, all new passenger cars sold in the EU must be equipped with TPMS. For N1 vehicles, TPMS is not mandatory, but if TPMS is installed, it must comply with the rules.
On July 13, 2010, the South Korean Ministry of Land, Transport and Maritime announced a delayed partial revision to the Korean Automobile Safety Standards (KMVSS), which stipulates that "TPMS will be installed into passenger vehicles and 3.5 GVW of vehicles.. [effective] on January 1, 2013 for new models and on 30 June 2014 for existing models. " Japan is expected to adopt EU legislation about one year after the implementation of the European Union. Other countries to make the TPMS shall include Russia, Indonesia, the Philippines, Israel, Malaysia and Turkey.
After the TREAD Act was passed, many companies responded to market opportunities by releasing TPMS products using battery-powered radio transmitter modules.
Average tire
The introduction of run-flat tires and emergency backup tires by some tire and vehicle manufacturers has been motivating to make at least some basic TPMS mandatory when using run-flat tires. With run-flat tires, drivers are unlikely to notice that the tires are moving, so the so-called "run-flat warning system" is introduced. This is the first generation of the most frequent, pure iTPMS-based roll-radius, which ensures that run-flat tires are not used beyond their limitations, typically 80 km/h (49.7 mph) and 80 km (49.7 miles) driving. The iTPMS market has grown as well. The indirect TPMS can detect below inflation through a combination of the use of roll radius and spectrum analysis and hence four wheel monitoring becomes feasible. With this breakthrough, meeting legal requirements is also possible with iTPMS.
Maps Tire-pressure monitoring system
Instant vs. not directly
Indirect TPMS
The indirect TPMS does not use a physical pressure sensor but measures air pressure by monitoring the rotation speed of individual wheels and other signals available outside the tire itself. The first generation iTPMS system is based on the principle that tires under inflation have slightly smaller diameters (and hence higher angular velocities) than are pumped properly. These differences can be measured through the ABS/ESC system wheel speed sensor. The second generation iTPMS can also detect simultaneous under-inflation across up to four tires using individual wheel-spectrum analysis, which can be realized in software using advanced signal processing techniques.
iTPMS can not measure or display absolute pressure value; they are relatively natural and must be rearranged by the driver once the tires are checked and all the pressure is adjusted properly. This reset is usually done by a physical key or in the on-board computer menu. iTPMS is, compared to dTPMS, more sensitive to the influence of different tires and external influences such as road surface and speed or driving style. The reset procedure, followed by an automatic learning phase typically 20 to 60 minutes of driving in which the iTPMS learns and stores the reference parameters before it becomes fully active, cancels a lot, but not all of this. Because iTPMS does not involve additional hardware, spare parts, electronic or toxic waste and any service (beyond the usual redeployment), they are considered easy to handle and very customer friendly.
Since the installation of the TPMS plant becomes mandatory in November 2014 for all new passenger vehicles in the EU, various iTPMS have been approved in accordance with UN R64 Regulations. Examples for this are most of the VW group models, but also many models of Volvo, Opel, Ford, Mazda, PSA, FIAT and Renault. iTPMS is rapidly gaining market share in the EU and is expected to become the dominant TPMS technology in the near future.
The iTPMS is considered inaccurate by some in part because of its nature, but given that a simple ambient temperature variation can cause pressure variations that are as large as the legal detection threshold, many vehicle manufacturers and customers appreciate the higher ease of use and tire changes. of theoretical accuracy of dTPMS.
Direct TPMS
TPMS directly uses pressure sensors on each wheel, both internal and external. The sensor physically measures the tire pressure on each tire and reports it to the vehicle instrument cluster or the corresponding monitor. Some units also measure and warn the tire temperature as well. This system can identify inflation below in any combination, be it one tire or all, simultaneously. Although the system varies in transmission options, many TPMS products (both OEM and aftermarket) can display real time tire pressure at each monitored location whether the vehicle is moving or parking. There are many different solutions, but they all face the problem of unfriendly environmental exposure. The majority are supported by batteries that limit their useful life. Some sensors use a wireless power system similar to that used in RFID tag readings that solve the problem of limited battery life by electromagnetic induction. It also increases the frequency of data transmission up to 40 Hz and reduces the weight of sensors that can be important in motorsport applications. If the sensor is installed on the outside of the wheel, such as some aftermarket systems, the sensor is subjected to mechanical damage, aggressive fluid, and theft. When mounted on the inside of the circle, they are no longer easily accessible to replace the battery and the RF link must overcome the effects of tire weakening that increases energy demand.
The direct TPMS sensor consists of the following major functions that require only a few external components - for example. battery, housing, PCB - to get the sensor module fitted to the valve rod inside the tire:
- pressure sensors;
- analog-digital converter;
- microcontroller;
- system controller;
- oscillator ;?
- radio frequency transmitter;
- low frequency receiver, and
- voltage regulator (battery management).
Most dTPMS installed initially have sensors mounted on the inside of the rim and the battery can not be redeemed. This means that when the battery reaches the end of its useful life, all sensors must be replaced. And even if it is possible to insert a new battery into the old sensor, it will not make much difference, because the sensor is equipped with sensitive electronic elements, which also wear out with time and is affected by pressure and vibration. When used in low-profile wheels, TPMS sensors wear out faster, and when used in poor road conditions. With a battery change it means that the entire sensor must be replaced and the exchange becomes possible only with the tire down, battery life becomes a very important parameter. To save energy and extend battery life, many DTPMS sensors do not transmit information when it is not spinning (which removes the monitoring of the spare tire) or implements complicated and expensive two-way communication that allows for sensor awakening. For OEM auto dTPMS units to function properly, they need to recognize the position of the sensor and must ignore the signal from other vehicles. There are many tools and procedures to make dTPMS "learn" or "relearn" this information, some riders implement, others are done by the workshop. The cost and variety of parts, procedures, and equipment has caused problems and confusion for customers and workshops.
The aftermarket DTPMS units not only transmit when the vehicle is moving or parking, but also provide users with various advanced monitoring options including data recording, remote monitoring options and more. They are available for all types of vehicles, from motorcycles to heavy equipment, and can monitor up to 64 tires at a time, which is important for commercial vehicles. Many aftermarket dTPMS units do not require special tools to program or reset, making them easier to use.
Maintenance issues
Parent-valve corrosion
The first generation TPMS sensor integrated with the valve stem has been corroded. The metal valve seal can be seized to the valve rod due to the galvanic corrosion of different metals, and attempts to remove it can break the rod, destroying the sensor. A similar fate may befall the core of the brass valve after a market inside the rod that may have been installed by an unwary technician, replacing the original core of the original nickel. (They can be distinguished by yellowish color from brass.) Valve sealing can complicate the repair of tire leakage, may require replacement of all sensors.
Compatibility tire sealant
There is controversy over the compatibility of after-market tire sealants with dTPMS using sensors mounted inside the tire. Some sealant manufacturers claim that their product is compatible, but others warn that "sealants may come into contact with the sensor in a way that makes the sensor unable to operate until it is thoroughly cleaned, checked and reinstalled by professional tire care." Such doubts are also reported by others. Use of the sealant may void the TPMS sensor warranty.
Benefits of TPMS
The dynamic behavior of pneumatic tires is closely related to the inflation pressure. Major factors such as braking distances and lateral stability require inflation pressures to be adjusted and maintained as determined by the vehicle manufacturer. Extreme extreme inflation can even lead to thermal and mechanical overload caused by overheating and subsequently, the sudden destruction of the tire itself. In addition, fuel efficiency and tire wear are strongly influenced by low inflation. Tires not only leak air if punctured, they also emit air naturally, and over a year, even properly installed new tires can lose 20 to 60 kPa (3 to 9 psi), about 10% or even more. initial pressure.
The significant advantages of TPMS are summarized as follows:
Fuel savings: According to GITI, for every 10% of under inflation on every tire on a vehicle, a 1% reduction in fuel economy will occur. In the United States alone, the Department of Transportation estimates that under inflated tires spend 2 billion gallons of US (7,600,000 m 3 ) of fuel each year.
Long life tires: Inflated tires are the cause of tire failure # 1 and contribute to tire disintegration, heat buildup, ply separation and side walls/casing damage. Furthermore, a difference of 10 pounds per square inch (69 kPa; 0.69 bar) in pressure on a set of duals literally drags a lower pressure tire 2.5 meters per kilometer (13 feet per mile). In addition, running the tires even briefly at inadequate pressure breaks the casing and prevents the ability to retread. It is important to note that not all sudden tire failures are caused by lack of inflation. The structural damage caused, for example, by hitting sharp or perforated curbs, can also lead to sudden tire failures, even certain times after damaging incidents. This can not be proactively detected by any TPMS.
Decrease in rest and maintenance time: Installing a TPMS for a vehicle will cut the expensive time off caused by non-inflation tires. This will also reduce the complexity of the treatment because you will not have to bother checking the tire pressure with the manual meter.
Better Security: Overheated tires lead to site separation and tire failure, resulting in 40,000 accidents, 33,000 injuries, and 650 deaths per year. Furthermore, well-pumped tires add better stability, handling, and braking efficiency and provide better security for drivers, vehicles, loads and others on the road.
Environmental efficiency: inflated tires, as predicted by the Transport Ministry, release more than 26 billion kilograms (57.5 billion pounds) of unnecessary carbon monoxide pollutants into the atmosphere each year in the United States alone.
Further statistics include:
The French SÃ © Ã © curitÃÆ'ÂÂ © RoutiÃÆ'¨re, a road safety organization, estimates that 9% of all road accidents involving casualties are caused by a lack of inflation, and DEKRA Germany, a product security organization, estimates that 41% Physical injuries related to tire problems.
The EU reported that average inflation below 40 kPa resulted in a 2% increase in fuel consumption and a 25% tire life decline. The EU concludes that tires under inflation are currently responsible for more than 20 million liters of unnecessary fuel burned, dumping more than 2 million tonnes of CO 2 into the atmosphere, and for 200 million wasted tires prematurely around the world.
Privacy issues with TPMS directly
Because each tire transmits a unique identifier, the vehicle can be easily tracked using existing sensors along the way. This concern can be overcome by encrypting radio communications from sensors but such privacy provisions are not fixed by NHTSA.
Heavy duty vehicles
The US National Road Traffic Safety Regulation applies only to vehicles under 10,000 pounds. For heavy duty vehicles (Class 7 and 8, gross vehicle weight [GVW] over 26,000 pounds), most of the above mentioned systems are not functioning properly, requiring the development of other systems.
The US Department of Transportation has commissioned several studies to find systems that work in the heavy duty market that determines some of the goals required in this market.
SAE has tried to disseminate best practices, because the legal regulations for heavy vehicles have been left behind.
One problem is the lack of standardization. Tires are often purchased in large quantities and transferred between tractors over time, so a given TPMS system can only work with compatible sensors in the tires, creating logistical problems. RF systems for these units should also work longer, which can force the repeater system to be mounted on a tractor or trailer. It is expected that the battery life on this system should be in the range of five to seven years, because the cost to break the tires can be much more expensive. The maximum loading requirement of the US Department of Transport forces the manufacturer of the trailer to spread the load through multiple axles, resulting in a trailer with typically 8 to 12 tires, but as many as 96 tires on a special hauler.
The tire casing can have a typical life span of ten years or more, through some retreading processes. It has spawned a special industry that focuses solely on the problems found in the trucking industry.
The central inflation system originally claimed eliminated the need for pressure monitoring systems. Some of the major inflation systems are Meritor PSI, Hendrickson International, Stemco AERIS, and Vagia (mostly used in South America). They have not yet produced a complete solution, as they do not solve all the problems (ie, no support for the steering shaft), and they bring new problems with the maintenance of the rotary clutch in the hub cap. The inflation system can sometimes shorten the life of a tire by hiding the slow leak caused by embedded objects, which the rider will lose after checking the tire problem.
In order for the tire pressure sensor to be truly effective, it must have some ability to allow various groups of maintenance personnel to use it.
First, every driver should check before the trip, so this is beneficial if the tire pressure monitor has a readable indicator without the tool.
Secondly, it usually should have the ability to cover dual sets of tires in a certain way. This is also useful if the filling point can be centered so that inflation can be achieved easily without going through a small hand hole in the rim.
Third, it is necessary to have a wireless communications system that has a suitable range and battery life. It is important that the sensors regularly communicate the condition of "I live", because having a dead sensor could be worse than not having a sensor at all.
Fourth, the system must have the ability to adapt to changes in tires and trailers with minimal operator intervention. It is important to use systems that have a longer range, because repeaters increase costs.
These requirements can be met by systems with external pressure sensors connected to the valve rod on each tire. When the tire is replaced, the sensor is moved to a new tire.
Although this system can alert drivers about dangerous explosive conditions, they can not help the fleet tackle leaking tires, unless the driver reports them to fleet maintenance personnel before it is too late. It has spawned in recent years to monitor solutions that track tire conditions and send warnings to fleet maintenance personnel. This allows them to schedule leak maintenance on an exclusion basis, rather than having to manually check each tire. Many fleets today recognize that tire pressure checks are a major problem in law enforcement. Most have policies in place that require regular checks of each tire, however, this practice is not very effective due to the narrow scope of the problem, and the fact that it is difficult to get a full record of all the tire inspections.
Currently, the best system uses automated data collection. Some of them use a gateway reader that automates tire data collection to a database, or to a web portal, allowing maintenance operators to view data for the entire fleet in an instant. For long-distance fleets that may not see their vehicles for long periods of time, centralized reading systems may not work, but there are emerging systems that combine the tire pressure sensor data back into the asset tracking system so that alerts can be sent back to the main office when an issue appear. For small fleets, there is a handheld device that lets one check the tires to simply drive around the vehicle and collect data for download to a central database, enabling law enforcement and trends to be made without errors.
Some automotive manufacturers have tried to extend their scope to a heavily marketed market, some manufacturers concentrating only on this market.
Icons
See also
- Central tire inflation system
- Cold inflation pressures
- Nira Dynamics AB
- Tire pressure gauge
References
External links
- Media related to Ban pressure monitoring system on Wikimedia Commons
Source of the article : Wikipedia
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