air compressor monitoring

This topic contains 6 replies and was last updated by geoff-finlay 9 years 1 month ago
July 24th, 2012 5:27pm
Hi All,

I,m new to your forum, so please be gentle. I'm looking for information regarding any monitoring of an air compressor's activity via a scan tool. Can anyone tell me if any of the major Truck OEs control or monitor the air compressor via either the "PCM" or other form.

Also are there any makes that provide bi-directional control of the air compressor's activity.

So far it looks as if none of the types of trucks I've looked at have any "interest" in the air brake system being integrated with the PCM. If that is correct, I wonder why not.

Thanks for any help

Geoff Finlay
July 25th, 2012 7:35am
Interesting thoughts and interesting conceptualizations. Do progress it.

The majority of compressor systems work with pressure oil lubrication and are water cooled. Failures are typically the result of overheating due to lack of water or lack of lubrication. Companies that work with Predictive Maintenance usually replace air compressors around 8,000 to 10,000 hrs of service, based on average life expectation.

But an air compressor is largely built like an engine, and when properly maintained, should last like an engine. Everything wears out, but with better monitoring and controls, it should be able to last much longer. What these companies do not want is a truck coming in on a hook because of a eight hundred dollar part.

Testing and monitoring compressor outflow is not done except if the driver conducts his pressure and pressure drop tests. Most mechanics these days have never been exposed to orifice testing, but it is a test that should be done more to ensure the compressor has the capability to supply volume.

Integrating sensors on the compressor is definitely possible and logical. Flow monitoring would be more difficult but necessary if companies are to be persuaded that this would have a cost benefit over time.
July 25th, 2012 1:37pm
Hi Jim,

Thanks for that input. There is a reason I'm trying to get all of the info I can in this area. I've done quite a lot of field work prior to designing the Air Brake Solution. I was looking at how many heavy trucks leaked air. I was also looking at how a Tech goes about finding & fixing those leaks.

About a year ago I had the chance to test some brand new Volvos during their PDI. None of them leaked air at all, they were perfectly tight. I then went to the used Volvo shop (end of lease/trade ins etc) and tested some 2,3 & 4 year old Volvos. They all leaked, some pretty badly.

I was also asked by a number of shops to help them find leaks that were problematic. These were large leaks that the tech couldn't locate (no noise) despite putting in many hours trying to find them. In each case I located the leak or leaks inside 30 minutes, using our equipment.

What was surprising to me was the percentage of trucks that leak and the relative size of those leaks. That led me to begin calculating the energy being used to replace the leaking compressed air and it's not insignificant in some cases, but alarming in many.

Even though we have the equipment to find & fix any leak quickly, it has still led me to research the possibility of monitoring air pressure and compressor activity. As you point out, overheating is one of the main causes of compressor failure, and a compressor that is constantly cycling is being set up for that possibility. That said, in many cases, the additional cost in fuel to support this type of operation would pay for that compressor before it finally fails.

I have lots of info that may be useful to an HD Tech involved in air leaks. I don't want to wear out my welcome. If there's any interest, let me know. = Geoff

July 29th, 2012 10:06pm
Wow that's a cool thought,integrated with the ECM.I think it would be great to be able to show the flow rate,it would take a lot of guess work out of annual inspections.Currently I have to time the air compressor build-up to get an idea if the compressor is good enough to be road worthy.Most of the compressors I change are due to excessive oil blow-by,just plain worn out.

I recently had one of those large air leaks without an audible leak.The air dryer was constantly purgeing,shut the engine off and no audible air leaks.I suspected the purge valve to be the trouble.So in with a new dryer cartridge and purge valve.Still had the same problem and to make a long story short the new purge valve was faulty.The air was leaking from the wet tank and I didn't see it till I put a gauge into the air line to the govonor from the wet tank.The trucks own gauges didn't show it either because they are piped into the dry tanks.I do like the quick connect air fittings when trouble shooting because the job is just so much faster.

What is this Air Brake Solution you are talking about?I am interested now.
July 30th, 2012 12:43am
Hi Will,

Thanks for the interesting response. I can sympathize with you trying to fix multiple large leaks when you can't hear any of them. That's one of the issues I'm trying to get across to the trade, that they miss many leaks because they don't always make a noise inside our hearing limits.

We're looking at developing a system that would monitor all of the parameters that you would need to do your job in just a few minutes, without the frustration of having to either fix it in 2 or three stages or just plain guess based on your experience. Just a caution about quick disconnects. We've rejected a number of standard disconnects just because they leak. Not necessarily out of the box, but you really get what you pay for in the disconnect business and the better ones (obviously more money) just plain last longer. We buy a lot of them and have to warrant them too.

Most shops don't know it, but some spend literally thousands of dollars a year paying for air leaks from air lines & quick connects. Compressed air is really expensive to replace.

The idea of developing an air brake monitoring system is something we're seriously looking at. We have the ability to do it, it's just a question of how to approach it and would it be a popular product. That's why I'm asking techs from different manufacturers to let me know if it's possible to "break" into the data stream that already monitors these parameters. So far it doesn't look like any OE has linked any of the air systems to the on-board computer. Frankly that's what we expected, since trucks are really about 15 years behind cars in terms of scan tool info.

I don't want this to be an advertisement, so re the Air Brake Solution, I absolutely guarantee you that using our combination if you had 2 leaks as described, you could measure their size, locate them, fix them and confirm your results in less than 60 minutes, 100% every time. Go to our website and look for yourself. We're just introducing it in Canada and we'll be in the US before long. Email me any questions you have at [email protected] I'll call you if you leave a number.

Everyone else, I hope this is acceptable, I'm just responding to a member. - Geoff

October 15th, 2012 1:03pm
I know Volvo trucks monitor the lifespan of their compressors, after changing them we had to "reset" that parameter that calculates the amount of air its pumped. How it does this I'm not sure. We changed them out at 500 000km/once a year.
October 15th, 2012 2:38pm
Mitchell, That's very interesting. For the information to be accurate there would have to be an air flow meter in line after the compressor, but I doubt that's the case, I've looked at a few Volvos. If I had to guess I'd think that Volvo have an algorithm based on engine run time plus maps of the type of driving such as speed, distance, idle time etc and calculate from those inputs... just a guess though.

Unless there's an actual air flow meter, it would be very difficult to account for air that was pumped and escaped through leakage. New Volvos leak very little, if at all, but once they have a little time on them, they leak like every othe truck.


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