The following is an excerpt from an interview conducted by Robert Pell of International Mining Magazine with Rob Kalwarowsky of Fluid Life regarding Fluid Life’s research project dealing with effect of Tier 4 Engine design on Oil Analysis Flagging Limits.
Since 1996, off-road diesel engine applications have been regulated under tighter emission standards from the US Environmental Protection Agency, Environment Canada, and the European Union which has led manufacturers to force emission particulates into the engine oil. The emission standards have gotten tighter over the years and have culminated, in January 2015, in the Tier 4 Final emission standards being enforced across North America in all newly manufactured diesel engines.
Robert Kalwarowsky, Senior Reliability Specialist at Fluid Life led a study that examined how new Tier 4 engines require different considerations when choosing oil and told IM about the results obtained by Fluid Life on this topic. For this preliminary study, Fluid Life analyzed over 22,000 oil samples from the two models of engines with the highest populations of Tier 4 classifications.
Why did you decide to investigate Tier 4 diesel engines?
In order to reduce emission particulate (because of the environmental regulations), some manufacturers redesigned their engines to add a portion of the exhaust gas back into the combustion chamber. After learning about the redesign, Fluid Life’s primary concern was an increase in soot in the engine oil, causing damage to the engine. Our analysis shows that, in some cases, soot is indeed increasing in these models of engine, although not to exceedingly high values.
What is Fluid Life doing to combat these issues?
Fluid Life has introduced tiered flagging limits for its diesel engines in order to account for the engine design changes.
Why is that an improvement?
In the case of these particular models, using non-tiered limits would flag Tier 4 Interim engines too often and may miss potential issues in the other models.
Were there any changes in wear metal generation?
In general, the Tier 4 engines generate less wear metal than their counterparts. Outside of copper, all 99th percentiles show a decrease from non-tiered groupings. The increase in copper is potentially caused by rocker arm wear, break-in wear on new engines or from cooler core leaching, as most of the Tier 4 engines in the analysis are relatively new. Potential reasons for the improved cleanliness are stringent oil and filter changes at 250-300 hours and the additions of spinner filters.
Silicon is often associated with dirt & dust entry, did you notice any changes with the Tier 4 models?
With one of the models analyzed, the data displayed a small increase in the amount of silicon in the Tier 4 Interim engines. This may be residual impact from the sealant used during manufacturing, silicon leaching from the seals and gasket in the factory fill oil or other sources but it is unlikely to be from dirt. However, from an overall perspective, there is minimal impact on the 99th percentile.
Did you notice any problems with engine reliability?
Yes, for one of the models in both Tier 4 Interim and Final engines, there were a number of top end coolant leaks which caused a large amount of sodium and potassium to be found in the oil samples. A possible cause for the increased risk of coolant leaks is the addition of an EGR cooler (which is also glycol cooled), adding more area for damage (and therefore leaks). For both potassium and sodium, Fluid Life says it will not be limiting its alarm limits.
After your study, do you have any conclusions or recommendations for sites operating Tier 4 diesel engines?
- Ensure oil and filter changes (including the DPF filter) occur at or before OEM recommended intervals. Doing so will prevent the buildup of soot, dirt, dust or wear metals.
- If possible, idling should be limited to prevent buildup of soot
- Ensure the regeneration of DPFs is performed when needed to reduce the buildup of soot
- Check oil analysis results for potassium and sodium without glycol. If this is the case, in addition to regular troubleshooting practices, check the EGR cooler system for leaks.
- Ensure all engines have tier information in myLab.
Download complete study here: How Tighter Emissions Regulations Are Changing Your Oil & What You Can Do About It