Online oil condition monitoring has been proven to detect short term events and abnormal patterns in oil quality degradation. However, online oil condition monitoring is also extremely useful in the long term to extend oil life and maximize the equipment’s useful operating life. Read this case study to hear more about life maximization in a diesel truck engine.
One of Poseidon’s online oil quality sensors was installed in an on-highway diesel engine from which oil lab samples were also collected. Throughout the application, the engine components were subject to various abnormally high loads and temperatures. These high loads and temperatures resulted in rapid oil degradation and several oil changes over the duration of installation.
One raw sensor output from the sensor is Bulk Resistance. The Bulk Resistance is sensitive to oil polar additives, oxidation products, and other contaminants. Bulk Resistance shows a rise in value as during oil break-in and a downward trend of is indicative of decreasing additive health as the oil naturally degrades with use. The Bulk Resistance measurements for this sensor can be seen in the graph below, as compared to total base number (TBN) measurements via standard lab analysis:
As the graph clearly shows, the bulk resistance showed very good correlation with lab nitration, oxidation and TBN measurements, as shown by the green dots on the secondary (right) axes. The downward trends of the sensor mirrored the lab TBN measurements, indicating the sensor can accurately reflect the results from the more labor-intensive lab sampling. This engine logged more upwards of 1400 operating hours and the online sensors consistently and reliably provided accurate measurements. If the Bulk Resistance trended below its limit, it would indicate need to change the oil due to depleted additives or aged oil. When using online oil condition monitoring sensors, the alarm indicator would be provided in real time during operation, as the asset is generating revenue, versus traditional lab sampling that would occur days if not weeks after the engine was subjected to the harmful conditions.
Not only does on-line real time monitoring expediate the oil monitoring process, it can help reduce costs by removing some of the conservatism in condemning criteria necessary in a lab sampling paradigm. Since the lab sampling inherently has a lag between measurement and remedial action, the condemning levels of used necessarily must be lower, more conservative, than a method that monitors the oil in real time. In other words, any actions taken based on lab sampling must take in to account the time between sample and action, since the asset continues to operate with that oil. It must be assumed the oil will continue to degrade during the time it takes to conduct the sampling, time during which the oil condition continues to worsen. Therefore, recommendations based on lab sampling are necessarily more conservative to reduce the risk to the asset. However, if monitoring the oil in real time, one could reduce the conservatism because there is no measurement lag time, and thereby reduce costs associated with replacing oil too soon.
In most applications, an oil quality sensor alone cannot replace a high quality, lab-based oil sampling protocol since it cannot provide all the same level of detailed analysis. Instead, an online EIS-type oil quality sensor can help reduce the amount and frequency of lab sampling that is needed, while affording protection against both normal and abnormal degradation modes. Lab sampling can be conducted as needed, when needed, based on the measured condition of the oil and not based on calendar or operating time. Thus, converting the costly lab sampling from time-based periodic maintenance to condition based maintenance. This means that in the long term, you can save even more money by implementing online oil sensors and saving money through decreases unnecessary waste with each and every oil change.
To read more about eliminating period fluid sampling, download our white paper on the subject here!