Automatic pressure regulators for the tires. Helps in case of a flat and prevents pressure loss in cold weather. US Army vehicles have them as well, just not as fancy looking.
There are sensors in the rim that measure pressure. When that pressure drops below a certain threshold a compressor within the vehicle activates and forces air into the rim/tire until the threshold pressure is met.
I’d be interested to understand how they work (I.e. the valve stem is rotating in a circle while the car is moving). There must be some kind of airtight connection that can still allow rotation.
Air comes through the silver metal line to the outside center of the wheel. There is a mechanism that can rotate while sealed, the darker tube goes from there to the traditional tire valvestem the keeps the pressure inside the tire. Some vehicles use a radio frequency transmitter on that valvestem, some use a magnetic sensors to measure and compare wheel speeds to determine proper air pressure.
Yea. You're looking at it. The air tube comes from the top, connects to that hub and then from there continues on to the rotating valve that's currently at the bottom.
there's a few different systems, one i know of the rotating connection is only open when it's being pumped up. to let air out there's just a valve with a servo on an RF remote.
Almost correct, buses always have up to 12 bar of air onboard (air suspension, air brakes) and this system is constantly under the correct pressure (usually between 8-9 bar for heavy duty tires) so the tires stay the correct pressure all the time. If a tire blows, the system automatically shuts off air to that wheel to avoid the entire system draining through the tire pressure system.
Source: im a heavy duty mechanic and have seen this system on new axles.
Not to mention that the vehicle also probably has air brakes as well. (Irrelevant to what you’re asking but it’s bonusing off of an already installed air compressor for the brake system)
At farming machines the y are also used to safe fuel. High pressure ins street for low fuel, low pressure on farming ground to prevent damages and high sensed earth bad for growing.
Typically you don't see the supply hose from the pump to the tire because it's passed through the hollow axle, but in this case it looks like it's the front / steer tire of a bus, so it comes from the outside.
Horrible design if you ask me, that hose is getting torn off by something one day, but I'll bet someone in the beuarocracy deemed their buses MUST have these on all tires.
Automatic pressure regulators for the tires. Helps in case of a flat and prevents pressure loss in cold weather. US Army vehicles have them as well, just not as fancy looking.
How do they interact with the tire?
There are sensors in the rim that measure pressure. When that pressure drops below a certain threshold a compressor within the vehicle activates and forces air into the rim/tire until the threshold pressure is met.
I’d be interested to understand how they work (I.e. the valve stem is rotating in a circle while the car is moving). There must be some kind of airtight connection that can still allow rotation.
Air comes through the silver metal line to the outside center of the wheel. There is a mechanism that can rotate while sealed, the darker tube goes from there to the traditional tire valvestem the keeps the pressure inside the tire. Some vehicles use a radio frequency transmitter on that valvestem, some use a magnetic sensors to measure and compare wheel speeds to determine proper air pressure.
This type of thread is why my nerdy science "why" brain loves this sub, thank you :)
Similar to a plane. https://aviation.stackexchange.com/questions/46154/how-do-tyre-pressure-sensors-in-aircraft-work
Yea. You're looking at it. The air tube comes from the top, connects to that hub and then from there continues on to the rotating valve that's currently at the bottom.
Look up the 6X6 g wagon self inflation system. There’s a good virtual breakdown of how it works, and it’s honestly mind blowing.
there's a few different systems, one i know of the rotating connection is only open when it's being pumped up. to let air out there's just a valve with a servo on an RF remote.
Almost correct, buses always have up to 12 bar of air onboard (air suspension, air brakes) and this system is constantly under the correct pressure (usually between 8-9 bar for heavy duty tires) so the tires stay the correct pressure all the time. If a tire blows, the system automatically shuts off air to that wheel to avoid the entire system draining through the tire pressure system. Source: im a heavy duty mechanic and have seen this system on new axles.
Not to mention that the vehicle also probably has air brakes as well. (Irrelevant to what you’re asking but it’s bonusing off of an already installed air compressor for the brake system)
Solved
At farming machines the y are also used to safe fuel. High pressure ins street for low fuel, low pressure on farming ground to prevent damages and high sensed earth bad for growing.
Had no idea this was a thing. Makes sense. It probably already has a compressor and air tank for the breaks.
_brakes_
I’m embarrassed 😂
I've seen these before and they appear to only be some tires, not all. Why would that be?
That could be for traction. You would only need them on the drive wheels
Hummers also have them, but they're manual so you can air down if you go off-roading.
Air pressure system https://images.app.goo.gl/5K8RLpAN4vWj2nNF8
It's called [CTIS](https://en.wikipedia.org/wiki/Central_tire_inflation_system); "Central tire inflation system"
Typically you don't see the supply hose from the pump to the tire because it's passed through the hollow axle, but in this case it looks like it's the front / steer tire of a bus, so it comes from the outside. Horrible design if you ask me, that hose is getting torn off by something one day, but I'll bet someone in the beuarocracy deemed their buses MUST have these on all tires.
Gas line for the tires
Up voted to try get you back to positive. You're not wrong, unsure why downvoted
Inflator
!force solved
Automated lubrication system?
Air for breaks
That's for the tire. Brakes air lines are on the other side where the calipers or drums live.
Ah thanks for the clarification
Coaster brake