What is a Tire Pressure Monitoring System?
If you buy a modern vehicle from the last few years, they are full of high tech safety equipment and systems, and
one of the most important, yet often overlooked by us as drivers, is the Tire Pressure Monitor System. Also known as
the TPMS, it provides real-time information about the air pressure in each tire.
This allows us as drivers to know if a tire is over or underinflated, which helps spot potential leaks or punctures
early, but in today’s vehicles, it is also important for overall performance. The latest vehicles, especially those
powered by electric motors , and finely tuned to
deliver maximum efficiency, and that includes tire compounds and the
pressures they are used with. Over or underinflated tires can knock significant miles off the range of an electric
car due to less efficient operations, and so the system is often integral to proper vehicle operations.
How does the Tire pressure Monitoring System work?
This depends on the type of PMS in use. There are two, direct or indirect tire pressure monitoring, and they wok in
slightly different ways.
Here is how the Direct TPMS functions:
Sensor Activation: Each tire is equipped with a pressure sensor. When the vehicle is started or in
motion, these sensors activate.
Pressure Measurement: The sensors in each tire measure the actual air pressure inside the tire.
Data Transmission: Measured pressure data is transmitted wirelessly from each sensor to the vehicle’s
onboard computer system .
Analysis: The vehicle's computer system analyzes the data, comparing it against
manufacturer-recommended pressure levels.
Alerting the Driver: If any tire's pressure is below or above the recommended level, the system
alerts the driver via a dashboard indicator light or message.
However, this is the process for an Indirect TPMS:
Wheel Speed Sensors Activation: Indirect TPMS utilizes the vehicle's Antilock Braking System (ABS)
wheel speed sensors.
Speed Analysis: As the vehicle moves, the ABS sensors monitor the rotational speed of each wheel.
Pressure Inference: The system calculates the relative air pressure in each tire based on the
assumption that under-inflated tires will rotate at a different speed compared to properly inflated tires
due to their smaller diameter.
Comparison and Calculation: The computer system compares rotational speeds of the tires to infer
which might be under or over-inflated.
Driver Notification: If the system detects an anomaly suggesting under-inflation, it triggers an
alert to the driver through the dashboard display.
While they take a different approach, as a driver, they both offer the same functionality, providing warnings if the
tire pressure is higher or lower than it should be for the best performance. While direct systems use data taken
from each tire individually, indirect systems give readings based on other factors instead. But which is better?
They both have pros and cons, with cost and functionality being the main ones.
Pros and Cons of TPMS
Pros
Increased Safety - With real time information about tire pressures, as drivers we have
immediate warnings if a tire has an issue, avoiding failures while moving.
Better Fuel Efficiency - Both under and over-inflating tires can mess with vehicle efficiency,
increasing fuel consumption. With TPMS, we can keep tires within the recommended levels.
Less Tire Wear - By keeping to the expected pressures, tires wear less than they do if left
with less or more air than they should have, lowering running costs.
Cons
Cost - TPMS adds cost to vehicle production, although indirect TPMS systems are much cheaper
than the direct ones. This is also true for maintenance, where replacement sensors can be an expensive
purchase.
False Alarms - TPMS can sometimes deliver a false reading, especially the indirect systems, and
that can mean we as drivers are left unsure and require further assistance to know we are safe.
Maintenance - Like all systems, TPMS need maintenance from time to time. Sensor replacements
will eventually be required, which can add to overall maintenance costs for any vehicle.
Conclusion
Not only do the latest Tire Pressure Monitor Systems make driving a vehicle safer, but they can aid with efficiency too, reducing fuel consumption for ICE vehicles, and helping maximize range for electric ones.
That combination of greater efficiency and lower wear on tires also makes the TPMS a factor in improving the
environmental impact of vehicle use. Moving forward, as
EVs seek to find every fraction of an efficiency advantage
that can find, the TPMS will be even more important, and likely to develop more accurate and reliable approaches to
real-time monitoring as a result.
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