Direct TPMS methods use pressure sensors to measure pressure in each of the four tires. Then these sensors transmit the pressure data via a wireless RF transmitter to a central receiver. The receiver communicates to a display that informs the driver which tire is underinflated. The tag in each wheel is designed to send a warning signal when a tire's pressure drops below its specified safety level. Tire-mounted pressure sensor is shown in Figure 1. Under-inflation has been cited as a cause of tire failures such as tread separation or tire blowouts. It is also responsible for shortening tire life and reducing fuel economy.
Indirect systems employ wheel speed sensors on a vehicle's anti-lock brake (ABS) system to track each tire's rotation. The premise is that under-inflated tires have a smaller radius, resulting in a higher rotational speed compared with a fully inflated tire. The sensor is supposed to detect the faster rotation, and the system alerts the driver. In practice, this change in radius is small, making indirect measurement less reliable than direct pressure measurement.
Constant monitoring of inflation pressure, tire temperature, tire sensor identification and battery life while driving and when standing still
Prevents the consequences of low tire pressure through early detection:
Punctures (approx. 80% of punctures are caused by inadequate tire pressure)
Increased tire wear due to added flexing work
Increased fuel consumption due to higher rolling resistance
Always provides optimum driving comfort
Driver is informed immediately of deviations from setpoint
In a typical temperature profile functionally reliable up to 120C, temperature-resistant up to 170C
Reliable up to 2000 g acceleration (static) and approved for numerous high-speed vehicles
Vibration resistant and even suitable for use with snow chains
Flexible design for almost all rim applications
Tire inflation pressure can be individually specified and therefore tailored exactly to the loading of the vehicle
Self-learning system with automatic individual wheel detection, leading to faster and more efficient wheel changes
Saves the troublesome, inconvenient and inaccurate testing at gas stations (the tires warm up while driving to the gas station, while the specified values apply to cold tires)
Reduces fuel consumption and the release of CO2 into the atmosphere
How to keep your tires properly inflated:
1: Check tire pressure at least once a month and before going on long trips. Since temperature affects tire pressure, it is best to check tires when they are cold, i.e. haven't been driven on for at least three hours.
2: Fill your tires with the pressure recommended on the tire label, located on the drivers door frame, sill or edge.
3: If you have any questions about your tires or maintenance, check your owners manual or consult your dealer.
Questions and answers:
Q: WHY IS PROPER TIRE INFLATION IMPORTANT:
A: Keeping your tires at the recommended pressure is essential for the safe and efficient operation of your vehicle. Safety experts estimate that 25 percent of automobiles are running on tires with lower than recommended pressure. Properly inflated tires run cooler, last longer, and improve fuel economy.
Q: WHY DOES TIRE PRESSURE CHANGE:
A: Many factors affect tire pressure, and that is why it is so important to check your tires at least once a month and before going on long trips. Tire pressure can decrease due to tire damage, slow leaks, or changes in outside temperature. For example, when the weather changes, your tire pressure changes too. For every drop of 10 degrees Fahrenheit in temperature, your tires lose 1 psi. Tires also deflate naturally over time, as much as 1.5 psi per month.
Q: HOW DOES THE NEW TIRE PRESSURE MONITORING SYSTEM WORK?:
A: Sophisticated sensors in the automobile continuously monitor tire pressure, and the warning light goes on when a tire is 25 percent or more below the appropriate tire pressure.
Q: WHEN WILL THE NEW TIRE PRESSURE MONITORING SYSTEM BE AVAILALBLE?:
A: The U.S. government, through the National Highway Traffic Safety Administration (NHTSA), requires Tire Pressure Monitoring Systems on all passenger cars and light trucks by the 2008 vehicle model year. Check your owners manual to see if your vehicle is equipped with a Tire Pressure Monitoring System. Many models have already been equipped with a system.
Q: IF THE WARNING LIGHT GOES ON AND OFF, WHAT DOES THAT MEAN?:
A: On cold mornings, the warning light may illuminate and then extinguish as tire pressure increases due to driving or outside air temperature increases. Additionally, if the warning light goes on and off, a malfunction in the system is indicated by a blinking light (for a period of 60 seconds to 90 seconds). After blinking for the brief time, the warning light can remain on. You should then contact your dealer for a system inspection.
Q: HOW SOON DO I NEED TO FILL MY TIRES IF THE LIGHT GOES ON?:
A: Please heed the warning light and check your tires as soon as possible.
Q: DOES THE WARNING LIGHT ALWAYS MEAN THAT THE TIRE PRESSURE IS LOW?:
A: The warning light may indicate a system malfunction requiring a dealers attention. If the warning light flashes before it is continuously on, but the tire pressure is found to be within the appropriate range, contact your dealer for a system inspection.
Q: WHAT ELSE DO I NEED TO DO FOR TIRE SAFETY?:
A: The Tire Pressure Monitoring System is a tool to keep you informed about low tire pressure, but it is no substitute for regular tire maintenance. Check your tire pressure at least once a month and before going on long trips. Consult your owners manual on replacing a tire or using a spare tire.