Any of you have information or know about vibration monitoring on mining haul trucks ? If so, are you using standard FFT technology or using some reciprocating analysis tool like Windrock or Dynalco ? If have some papers or links, please let me know.

Which parts of the truck do you want to monitor? The diesel engine?

Yes, Diesel engines on mechanical driven haul trucks.

Perhaps, you may want to search for ISO standard for evaluating vibration of diesel engines on mobile equipment.

PDM,

The size/type of diesel engines of large haul trucks do not appear to be very friendly for combustion pressure analysis. You should check the feasibility of making measurements before wasting time on recip-analysis.
Torsional vibration analysis is not a conventional method, but I would explore this because a single sensor can reveal a lot about all of the cylinders at the same time. Vibration measurements and ultrasound can also provide good fault detection. You have to decide what type of monitor situation you want to implement: permanent on every vehicle, portable for a ride on vehicle, test vehicle stationary with engine unloaded, or test in shop with chassis dyno or other load method. This is not an easy project if you want to do it well.

Hint on vibration: you need a tach signal for synchronous waveform as well as FFT spectrum measurements.

Walt

Hello PdM Doctor,
There are a couple of other issues in vibration monitoring for large diesel engines in haul trucks.
1. The conditions on-board (temperature, dust, vibration) require hardened electronics if your tooling is going to live,
2. Loading on mobile plant engines is highly variable as opposed to a generator or pump engine or other application that runs at constant load.

There are other useful techniques for determining the condition of these sorts of engines. What are you hoping to achieve with vibration monitoring?

Regards, Matt.

Thanks for your comments. I´m trying to find the way to measure vibration and ultrasound on haul truck diesel engines with FFT and recip analysis (windrock, dynalco).

I know pressure measurement is not viable, but think taking some vibration and ultrasound data could be useful, maybe with the truck unloaded and in a controlled environment (not on the road or on board).

Do you know about a similar experience in other mining operation ? Have you see this kind of monitoring in other place ? Have you tried this in the past ? How useful an unloaded data could be for this type of motor ?

PDM,

Several years ago I was working at a gold mine in Nevada that had a vibration program on their large diesel-generator electric drive haul trucks. I don't know if the program is still going.

If dynamic pressure measurements are not feasible, then why consider Windrock or Dynalco recip analysis products? Do you have a list of faults that you expect to detect by vibration or ultrasound? Do you have good training and experience with both vibration and ultrasound technologies? If not, then you are starting with a very difficult application for these technologies. These comments are based on many years experience with diesel engines in marine, industrial and utility applications.

Walt
w_f_strong [at] msn [dot] com

It is not feasible to measure pressure on cylinders, but it is possible to take phased vibration and ultrasound data with a Windrock or Dynalco tool. This will give me the chance to take care of integrity (main bearings, connecting rods, ..) and a litte bit of performance (valves). However, I´m not sure about the data quality with an unloaded truck and I would like to know about a similar program in other place. Don´t worry, I have the "know how" in recips. Thanks for your comments.

This message has been edited. Last edited by: Machine Doc,

PDM,

You must know that engine vibrations and ultrasound change with load. In general faults are more often revealed at full load than at no load. What has been your experience with other Recips? What are the engines mfg and model for the trucks under consideration?

Walt

Yes we agree, when I talk about "data quality" I´m thinking about load and the chances of getting good information from this testing. I have experience with stationary recips analysis(Superior, Waukesha, up to 16 cylinders). These trucks are CAT 793 with 3516 engines.

I have have visited many mines running this truck model, and have some experience with the engine in question.

I have not met anyone doing vibration analysis in the manner you described, so I can't offer any specific information.

If you wanted to attempt to do so, you would need to control as many variables as possible to ensure your results are repeatable. With that in mind, data collection "on the fly" on while loaded (with payloads that change every few minutes) on haul roads (that change daily) does not really meet this criteria. About the best thing you could try is taking measurements during a torque converter stall test, which is described in the OEM service manual. No idea if this will work, but I can't think of anything more repeatable (or safer).

May I respectfully suggest you revisit your oil analysis program (I've yet to visit a site that doesn't run such a program, but not many programs provide the value they possibly could). Additionally, the later versions of this model truck generate lots of data from the onboard monitoring system. There are guidelines available from your Cat dealer on which parameters provide good value and hence the ones to monitor closely. The performance and integrity issues you mentioned can clearly be identified using these two condition-monitoring techniques.

Good luck with your vibration monitoring, it would be interesting to hear some feedback on this board on your progress.

Matt.

Matt,

How long can a torque converter test be conducted before overheating occurs? I assume this test refers to the truck either pulling or pushing against a fixed anchor to load engine. My concern would be that there would not be enough time to measure vibrations on a cylinder by cylinder survey with a portable engine/vibration analyzer.

Walt

Hi Walt,
Yes, this test loads the engine in first gear against the parking and service brakes. Since the oil has to start at operating temperature, you do not have a lot of time before the transmission/torque converter oil temperature sensors detect an overheat and you need to stop (10's of seconds, not minutes).

Perhaps you might take one overall vibration level, but I can't see the practicalities of measuring each cylinder. This would require a few minutes (at high idle speed with no load) between each measurement to cool the oil circuit. Unless you could instrument each cylinder beforehand, you would then need to enter the engine compartment between tests to shift your accelerometers, which is quite hazardous due to radiated heat and numerous hot surfaces.

In reality this might take a couple of hours to complete per machine. I would envisage a very co-operative operations department that released each hauling unit for this duration on a regular basis.

Matt.

It would seam that the only practical approach is to scan/measure ultrasound/vibrations with engine at high idle and then install speed sensor and several accelerometers with a multi-channel DAQ system for one loaded test.

I have done several diagnostic tests on CAT 3516 marine engines, but it is a lot easier to work on than in a monster truck. I don't have any of these trucks in my back yard to play with! I have used torsional vibration sensors at engine flywheel and damper. I recommend including torsional measurements to detect abnormal cylinder firing along with other accelerometer or ultrasound measurments. A custom system is probably needed to minimize test time and to normalize data to repeatable operating conditions. My preference is for the instruments to accomodate the test rather than the test be forced to fit the instruments. Obviously one tries to use what's available until it becomes unsuitable.

Walt

MachDoc :

To answer your original question : yes I have monitored diesel engines using Gated Analysis and mechanical (and diesel electric drive) haul truck drive trains using Order Analysis.

Contact me direct if you have any specific questions.

Regards

Rob