Hyperactivity applauded in both hands across the AlpsI begin my tour Editor's note with the exhibitOscar on October 1The retirement home an economic barometerA television campaign is also on the menuMichel Camdessus told a conversation with MrsThe future of Christian Streiff is in any case issueOur customers don't pay not only for a vehicleIt has also unscrewed against the yen losing 1It's the least of things judge Bernard Devy FOIt is for example whole challenge of post 2How can a small optical sensor with air nothing be as smart This concentrate of high technology, protected by 8 international and European patents does not include less than 39 components in a black box the size of valve stopper! This is the core element of the new K-Pressure Optic tire pressure control system, developed by Pirelli after long years of studies. The challenge is for road safety. According to the automakers, three-quarters of car accidents are caused by failures of tyres to the inflation.
But should bear in mind that a tire on average, natural way, 0.2 loses bar every three months. In other words, if its lifetime is two years and its nominal pressure of 2 bar, he will suffer so four times a under-inflation of 20. With three direct impact: tread wear is increased by 25, life of the tire is reduced by 30 and the fuel consumption is increased by 3. Remains that the tyre pressure control is not an automatic reflex for all motorists. As confirmed by a study conducted last year by BVA and road safety, 89 of drivers are think less than once per year, most of the time for a long journey, for example for a departure on holiday.
It is the interest system K-Pressure Optic, composed of four sensors and a key to disassembly. It is sufficient to screw a sensor instead of the cap of each of the four valves. What is going on The sensor opens tire valve and air enters the small room until the nominal pressure for which it was designed. "Today, there are on the market a family of sensors for each level of 0.1 bar, in a range of 1.8 to 3 bar pressure, and we extend it up to 10 bar," says Massimo Filippi, "product manager" in Pirelli Tyre. Important point: "from the moment where he is screwed, pressure is controlled and the sensor no longer allows air to escape from the tire, regardless of the situation", he insists.
Fresnel lens
In the upper part of the sensor, there is a Fresnel lens which consists of two parts: the white and the other red. If the situation is in the balance, i.e. the tire pressure and domestic forces of the sensor, separates the two parts of the lens and by effect of diffraction of light, there is nothing. The optical signal at the top of the plug appeared visually white.
On the other hand, once this balance is broken, whatever the reason, it follows a loss of air, so a decrease in pressure. At the time, the main piston rises towards the top and firm the tire valve. At the same time, touch both sides of the lens and the optical alarm on the surface of the sensor turns red. Just a regular look of the driver see.
Connecting versions
"This sensor is designed to understand the origin of the loss of pressure, i.e. If it is due to a loss of air or a fall in temperature", explains Massimo Filippi. The main spring, which is placed at the base of the piston is made with a special material of the elastic constant changes with temperature, since it affects the pressure of the tire. The spring hardens as the temperature drops, which allows a total compensation above 15 C. Below this threshold, it is only partial. Signal is thus running as downward pressure to about 1.4-1.5 bar driven by this fall in temperature becomes dangerous driving. This is an additional security, even if there is no loss of air. Moreover, to avoid a problem balancing on the wheel, the outer envelope of this light sensor, which weighs 3.5 grams, is carried out in a material high performance Victrex Peek, whose physical and thermal properties have been tested in the aviation industry.
From K-Pressure technology, Pirelli has developed two other systems that are only differentiated by the mode of transmission of the signal. K-Pressure Acoustic version sends radio frequency signal via an on-board electronic management system to prevent the motorist. More sophisticated, the K-Pressure Acoustic Blue version, which transmits the signal via a wireless to a mobile phone link, is the only one to immediately diagnose the defective tire.
