Direct TPMS

Direct TPMS, or direct tire pressure monitoring systems (direct sensor TPMS) refers to the use of a pressure sensor directly mounted on the wheels or tires of a vehicle. The pressure inside the tire is measured using a pressure transducer with the pressure information being subsequently sent to the vehicle to warn the driver of under or over inflation of a tire. The pressure information is commonly transmitted to the vehicle using radio frequency (RF) technology, though systems using mechanical, electrical or magnetic methods have been used over recent years. Typical system direct TPM sensor fitted in valve system, manufacturer VDO In most current designs of direct TPMS, a small electronic assembly which is rugged enough to be mounted inside a tire, measures the pressure using a microelectromechanical system (MEMS) pressure sensor and then transmits this and other information to one or more vehicle receivers. Other information can include a serial number, temperature, acceleration and the status of the complete tire pressure monitoring system. The purpose of the serial number is to allow the vehicle to ignore transmissions from other vehicles and operate with a unique data field. A typical direct TPMS (e.g. Ford, BMW or Toyota) comprises the following components on a vehicle: A direct TPM sensor fitted to the back of the valve stem on each wheel A TPM Warning Light Unique identifier (ID's) for which tire is providing the data including speed and the direction of rotation A tire pressure monitor electronic control unit (ECU) Antenna(s) Controller for periodic measurements Source of power Diagnostics and wake up system Most direct TPMS systems use ultra high frequency (UHF) radio in one of the 'unlicensed' ISM bands (industrial, scientific and medical) for transmitting the data, often around 434 MHz in Europe and 315 MHz in much of the rest of the world. On some systems there is a separate receiver or antenna near each wheel whilst more commonly there is a single receiver which receives data from all of the wheels on the vehicle. Commonly this receiver is also used for remote keyless entry system (RKE) as this also usually uses UHF radio transmissions. TPM sensors can be fitted to the wheels in a number of ways. They can be mounted on the back of the tire's valve stem or attached using adhesive or to a band which is then securely wrapped around the rim inside the tire, usually in the drop zone. Direct tire pressure monitor system warning light When the direct TPMS warning light comes on, either one of the tires is under-inflated, severely over-inflated, or there is a fault with the system. If the light is constant then inflating to the correct placard pressure should turn it off. If this is not the case then this indicates a puncture. If...

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Tire-pressure gauge

A tire-pressure gauge, or tyre-pressure gauge, is a pressure gauge used to measure the pressure of tires on a vehicle. Since tires are rated for specific loads at certain pressure, it is important to keep the pressure of the tire at the optimal amount. Tires are rated for their optimal pressure when cold, meaning before the tire has been driven on for the day and allowed to heat up, which ultimately changes the internal pressure of the tire due to the expansion of gases. The precision of a typical mechanical gauge as shown is ±3 psi (21 kPa). Higher precision gauges with ±1 psi (6.9 kPa) uncertainty can also be obtained. A tire-pressure gauge in use. The example in this image is a Bourdon tube gauge. Built-in tire pressure sensors Many modern cars now come with built-in tire pressure sensors that allow all four tire pressures to be read simultaneously from inside the car. In 2005, most on-board Tire Pressure Monitoring Systems (TPMS) used indirect pressure monitoring. The anti-lock brake sensors detect one tire rotating faster than the rest and indicate a low tire pressure to the driver. The problem with this method was that if tires all lost the same pressure then none would show up against the others to indicate a problem. Regulations on tire pressure Since September 2007 all new automobiles below 10,000 lb (4,500 kg) in weight sold in the United States are required to incorporate a Tire Pressure Monitoring System, which is capable of monitoring all four tires and simultaneously reporting under-inflation of 25 percent of cold placard pressures in any combination of all four tires. TPMS known as Direct TPMS are capable of TREAD Act legislation requiring simultaneous pressure measurement for each tire pressure. Early TPMS sensors required batteries, but the latest TPMS technology eliminates all sensor batteries. References http://www.nhtsa.dot.gov/cars/testing/ncap/Tyres/pages/TPandLoading.htm http://etv.com.au

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Central tire inflation system

A central tire inflation system (CTIS) is a system to provide control over the air pressure in each tire of a vehicle as a way to improve performance on different surfaces. For example, lowering the air pressure in a tire creates a larger area of contact between the tire and the ground and makes driving on softer ground much easier. It also does less damage to the surface. This is important on work sites and in agricultural fields. By giving the driver direct control over the air pressure in each tire, maneuverability is greatly improved. Another function of the CTIS is to maintain pressure in the tires if there is a slow leak or puncture. In this case, the system controls inflation automatically based on the selected pressure the driver has set. Tractor-drawn trailer with CTIS Tatra T813 prototype had CTIS already in 1960, it later became standard for all Tatra military trucks CTIS is extensively used in many off-road transport operations. In many countries, especially Australia, New Zealand and South Africa, CTIS is used in logging, in mining, and in power line maintenance. CTIS significantly reduces environmental impact when transporting logs, or travelling on gravel or dirt roads. Benefits include ironing out ruts and previous road damage, like washboards or corrugations. Reducing the tire pressure also reduces the grinding action on the gravel, significantly reducing dust and silt. CTIS also extends truck, tire, and drive train life, by significantly reducing vibration and shock loading. Feedback from Australian logging contractors show a doubling of transmission and differential life. Tire life can double, with drive tire life increasing from 27,000 km to 45,000 regularly shown . Even in flatter areas, drive tire life increased from 90,000 to 135,000 . There have been attempts at employing central tire inflation system on aircraft landing wheels (notably on the Soviet Antonov An-22 military transport) to improve their preparedness for unpaved runways. Use CTIS was first used in production on the American DUKW amphibious truck which was introduced in 1942. The Czech heavy military 8x8 truck Tatra T813's central inflation and deflation system was designed to maintain pressure even after multiple bullet punctures. Military Tatra trucks are equipped with CTIS as standard. From 1984, GM offered CTIS for the Chevrolet Blazer and various pick-ups. Several trucks used by the U.S. military also have CTIS (e.g. the HMMWV and its civilian counterpart, the Hummer H1). The feature is also common in Soviet and Russian military trucks. References  "Central tire inflation system". Retrieved 2010-05-13.

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Uniform Tire Quality Grading

Uniform Tire Quality Grading, commonly abbreviated as UTQG, is the term encompassing a set of standards for passenger car tires that measures a tire's treadwear, temperature resistance and traction. The UTQG was created by the National Highway Traffic Safety Administration in 1978, a branch of the United States Department of Transportation (DOT). All tires manufactured for sale in the United States since March 31, 1979 are federally mandated to have the UTQG ratings on their sidewall as part of the DOT approval process, in which non-DOT approved tires are not legal for street use in the United States. It is not to be confused with the tire code, a supplemental and global standard measuring tire dimensions, load-bearing ability and maximum speed, maintained by tire industry trade organizations and the International Organization for Standardization. The National Highway Traffic Safety Administration (NHTSA) established the Uniform Tire Quality Grading Standards (UTQGS) in 49 CFR 575.104. When looking at UTQG ratings it is important to realize that the Department of Transportation does not conduct the tests. The grades are assigned by the tire manufacturers based on their test results or those conducted by an independent testing company they have hired. The NHTSA has the right to inspect the tire manufacturer's data and can fine them if inconsistencies are found.  Dedicated winter tires, also known as snow tires, are not required to have a UTQG rating. Non-passenger car tires, such as those for motorcycles, buses, medium trucks and above along with trailers are also not required to have a UTQG rating, although FMVSS Standard 109 requires the following to be listed on the tire's sidewall: speed restriction if less than 55 mph, regroovable if designed for regrooving, and a letter designating load range rating. UTQG ratings (top) and tire code(bottom) on sidewall of Continental ContiProContact tire Components The UTQG rating is made up of three components, treadwear, traction and temperature. Treadwear The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test track. A tire graded 200 would last twice as long on the government test course under specified test conditions as one graded 100. In theory, this means that a tire with a 200 grade will wear twice as long as a tire with a 100 grade. However, tire manufacturers are not under any obligation to grade a tire based on the test results, except to say that they cannot overstate the grade. This is enforced by NHTSA requiring documentation to justify any assignment of a grade on a tire, "These treadwear grades are no...

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Tire-pressure monitoring system

A tire-pressure monitoring system (TPMS) is an electronic system designed to monitor the air pressure inside the pneumatic tires on various types of vehicles. TPMS report real-time tire-pressure information to the driver of the vehicle, either via a gauge, a pictogram display, or a simple low-pressure warning light. TPMS can be divided into two different types – direct (dTPMS) and indirect (iTPMS). TPMS are provided both at an OEM (factory) level as well as an aftermarket solution. The target of a TPMS is avoiding traffic accidents, poor fuel economy, and increased tire wear due to under-inflated tires through early recognition of a hazardous state of the tires. History Initial adoption Due to the influence tire pressure has on vehicle safety and efficiency, tire-pressure monitoring (TPM) was first adopted by the European market as an optional feature for luxurypassenger vehicles in the 1980s. The first passenger vehicle to adopt TPM was the Porsche 959 in 1986, using a hollow spoke wheel system developed by PSK. In 1996 Renault used the Michelin PAX system for the Scenic and in 1999 the PSA Peugeot Citroën decided to adopt TPM as a standard feature on the Peugeot 607. The following year (2000), Renault launched the Laguna II, the first high volume mid-size passenger vehicle in the world to be equipped with TPM as a standard feature. In the United States, TPM was introduced by General Motors for the 1991 model year for the Corvette in conjunction with Goodyear run-flat tires. The system uses sensors in the wheels and a driver display which can show tire pressure at any wheel, plus warnings for both high and low pressure. It has been standard on Corvettes ever since. Firestone recall and legal mandates The Firestone recall in the late 1990s (which was linked to more than 100 deaths from rollovers following tire tread-separation), pushed the United States Congress to legislate the TREAD Act. The Act mandated the use of a suitable TPMS technology in all light motor vehicles (under 10,000 pounds), to help alert drivers of under-inflation events. This act affects all light motor vehicles sold after September 1, 2007. Phase-in started in October 2005 at 20%, and reached 100% for models produced after September 2007. In the United States, as of 2008 and the European Union, as of November 1, 2012, all new passenger car models (M1) released must be equipped with a TPMS. From November 1, 2014, all new passenger cars sold in the European Union must be equipped with a TPMS. For N1 vehicles, TPMS are not mandatory, but if a TPMS is fitted, it must comply with the regulation. On July 13, 2010,...

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Run-flat tire

A run-flat tire is a pneumatic vehicle tire that is designed to resist the effects of deflation when punctured, and to enable the vehicle to continue to be driven at reduced speeds - under 56 mph (90 km/h) - and for limited distances - generally between 10 mi (16 km) to 50 mi (80 km), depending on the type of tire. Cutaway model of MOWAG Piranha tire Technologies There are three basic technologies currently available, described below. Self-supporting The origins of the commercial self-supporting run-flat tire started in 1935 with a tire that had a fabric inner tire. The tire was advertised as a protection against blow outs, a common and dangerous occurrence in the 1930s. In 1934, Michelin introduced a tire that was based on technology developed for local commuter trains and trolleys. It had a safety rim inside the tire which if punctured would run on a special foam lining. The tire was sold for military use and for specialized vehicles like bank armoured cars. It was advertised as "semi-bullet proof". While the tire performed as advertised it was far too expensive to be a feasible option for most private automobile users. In 1958, Chrysler teamed with Goodyear Tire and Rubber Company to offer Captive Air run-flat tires using an interlining to carry the weight. In 1972 Dunlop launched the Total Mobility Tyre (later Denovo) "fail-safe" wheel and tire system that became optional equipment on the Rover P6 3500 in 1973, and by 1983 evolved into the TD/Denloc which became standard equipment across the whole Austin Metro range. Most recently, Bridgestone and Pirelli run-flat tires are supplied on some new model BMW cars. The automaker promoted these as a safety feature and as an alternative to carrying a spare tire. Self-supporting run-flat tires are now common on light trucks and passenger cars and typically provide for the vehicle to drive for 50 miles (80 km) at around 50 miles per hour (80 km/h). However, if the tires are subject to this kind of misuse, wheels may become damaged in the process, and repair may be impossible or unsafe, especially if the tire is punctured in the sidewall or at the edge of the tread. These tires carry a 20 to 40 percent weight penalty over similar standard tires. The thicker sidewall also means higher rolling resistance, which reduces the vehicle's fuel economy. Self-sealing These tires contain an extra lining within the tire that self-seals in the event of a small hole due to a nail or screw. In this way, the loss of air is prevented from the outset such that the tire is either permanently self-repairing or at least loses air very slowly. There are also a number of retrofitted tire sealants which act in...

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Airless tire

Airless tires, or non-pneumatic tires (NPT), are tires that are not supported by air pressure. They are used on some small vehicles such as riding lawn mowers and motorized golf carts. They are also used on heavy equipment such as backhoes, which are required to operate on sites such as building demolition, where risk of tire punctures is high. Tires composed of closed-cell polyurethane foam are also made for bicycles and wheelchairs.   12-16.5 Mk1 Croc Tyre with rim center fitted Advantages The main advantage of airless tires is that they cannot go flat. Other advantages are that airless tires will need to be replaced less often resulting in a savings. Heavy equipment outfitted with airless tires will be able to carry more weight and engage in more rugged activities. Airless bicycle tires can be easy to install. Airless lawn mower tires come in several varieties. Disadvantages Airless tires generally have higher rolling resistance and provide somewhat less suspension than similarly shaped and sized pneumatic tires. Other problems for airless heavy equipment tires include dissipating the heat buildup that occurs when they are driven. Airless tires are often filled with compressed polymers (plastic), rather than air or can be a solid molded product. Airless tires are attractive to cyclists, as bicycle tires are much more vulnerable to punctures than motor vehicle tires. The drawbacks to airless tires depend on the use. Heavy equipment operators who use machinery with solid tires will complain of fatigue whereas lawn mowers that use solid or airless tires have no drawbacks. Bicycle riders who use airless tires may complain that the tire is harder than a comparable pneumatic tire. Only anecdotal evidence exists that airless tires may cause broken spokes on a bicycle wheel. Any airless tire will be heavier than the rubber tire it is meant to replace; however, many rubber pneumatic tires are also heavy. Rubber tires vary in rolling resistance and an airless tire or solid insert may only marginally increase rolling resistance if at all. Installation of airless tires depends on the use. Heavy equipment will need special equipment to mount but an airless bicycle tire can be mounted with little or no effort. Solid airless lawnmower tires come pre-installed on the wheel allowing quick installation. Examples Mobike tire Many bicycle-sharing systems use these tires to reduce maintenance. In 2005, Michelin started developing an integrated tire and wheel combination, the "Tweel" (derived from "tire" and "wheel," which, as the name "Tweel" suggests, are combined into one new, fused part), which operates entirely without air. Michelin claims its "Tweel" has load carrying, shock absorbing, and handling characteristics that...

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