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Cummins ISM Reference Data Review for Cummins Surveillance Panel

Cummins ISM Reference Data Review for Cummins Surveillance Panel. August 26, 2009 Jim Rutherford. Introduction. At the August 13 Cummins Surveillance Panel conference call several questions were raised about ISM severity. Here is an attempt to address the following questions.

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Cummins ISM Reference Data Review for Cummins Surveillance Panel

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  1. Cummins ISM Reference Data ReviewforCummins Surveillance Panel August 26, 2009 Jim Rutherford

  2. Introduction • At the August 13 Cummins Surveillance Panel conference call several questions were raised about ISM severity. Here is an attempt to address the following questions. • Are the soot adjustments right? • Are the industry correction factors right? • Are the cross cylinder σ’s changing? • Should we update targets? • Should we use severity adjustments?

  3. 1. Are the soot adjustments right? • Background – According to the ISM Timeline March 22, 2005 marked “COMPLETION OF MINI-MATRIX ANALYSES AND IMPLEMENTATION OF SOOT ADJUSTMENTS FOR WEAR PARAMETERS” To the best of my memory, this mini-matrix consisted of 15 tests from four labs on three oils. Although I can’t find that analysis or notes from the meeting we had in Columbus and each time I have gone back to recreate what we did I get confused about which data are correct, the analyses looked something like this. So although we couldn’t get exactly the same numbers to many decimal places, we rounded to 3 and 1.7 and used the TGA average from 830-2 of 3.9

  4. 1. Are the soot adjustments right? (CWL) For crossheads, there was clearly more slope for the other two oils (1004-3 and ISMA) than for 830-2.

  5. 1. Are the soot adjustments right? (CWL) Since the implementation of soot adjustments, slope has maybe increased for CWL on 830-2. This chart shows industry corrected, outlier screened CWL without soot adjustment versus soot for the original seven tests with 830-2 and all references since then. The slope before is about 0.5 and for later a bit over 1.

  6. 1. Are the soot adjustments right? (CWL) This chart shows industry corrected, outlier screened, soot adjusted CWL versus soot for the original seven tests with 830-2 and all references since then. The negative slope over the soot range could be an indication that the soot adjustment is overcompensating for 830-2. This could make sense based on original data. But what is it doing for other oils?

  7. 2. Are the industry correction factors right? (CWL) This chart shows outlier screened, soot adjusted CWL versus date for all 36 chartable 830-2 results with and without industry correction. On the average, the correction looks not bad; maybe a little too much for more recent tests. Industry Correction Before After

  8. 1. Are the soot adjustments right? (CWL)2. Are the industry correction factors right? (CWL) This chart shows industry corrected, outlier screened, soot adjusted CWL versus date for all 36 chartable 830-2 results. Over the life of the test final results for 830-2 might have increased an average of 0.5 mg. Soot Adjustment Calc Before After Industry Correction Before After

  9. 1. Are the soot adjustments right? (IAS) For injector adjusting screws in the original mini-matrix data, 830-2 and 1004-3 had similar slope. ISMA had greater slope but only two results.

  10. 1. Are the soot adjustments right? (IAS) Since the implementation of soot adjustments, slope has apparently decreased for IAS on 830-2. This chart shows industry corrected, outlier screened ln(IAS) without soot adjustment versus soot for the original seven tests with 830-2 and all references since then. The slope before is over 1 and for later under 0.

  11. 1. Are the soot adjustments right? (IAS) This chart shows industry corrected, outlier screened, soot adjusted IAS versus soot for the original seven tests with 830-2 and all references since then. The negative slope over the soot range could be an indication that the soot adjustment is overcompensating for 830-2. This overcompensation contradicts mini-matrix conclusions for 830-2. But what is it doing for other oils? However, since later tests tend to have higher soot, it would be hard to say whether soot adjustment or industry correction or both contribute to the trend.

  12. 2. Are the industry correction factors right? (CWL) This chart shows outlier screened, soot adjusted IAS versus date for all 36 chartable 830-2 results with and without industry correction. On the average, the correction looks not bad; maybe not enough for more recent tests. Industry Correction Before After

  13. Are the soot adjustments right? (IAS)2. Are the industry correction factors right? (IAS) This chart shows industry corrected, outlier screened, soot adjusted IAS versus date for all 36 chartable 830-2 results. Over the life of the test final results for 830-2 might have decreased an average of 4 mg. Soot Adjustment Calc Before After Industry Correction Before After

  14. 3. Are the cross cylinder σ’s changing? This chart shows original measurement and outlier screened CWL standard deviations across the six cylinders for exhaust and intake by date. I don’t know what to say about it. No simple trends.

  15. 3. Are the cross cylinder σ’s changing? This chart shows original measurement and outlier screened IAS standard deviations across the six cylinders for exhaust and intake by date. Maybe the trend is downward?

  16. 4. Should we update targets? This chart shows previous three sets of targets. It seems that they were simple averages of all 830-2 tests available at each time. A possible update with current tests is shown.

  17. 4. Should we update targets? Actual target w/o industry correction 24.5 OFDP transformed back from ln(OFDP+1)

  18. 4. Should we update targets? Industrty didn’t believe this number. Used 0.20 instead. Actual sd w/o industry correction 10.7

  19. 4. Should we update targets?5. Should we use severity adjustments? • My opinion on these last two questions: • Yes, we should update targets. But not as shown above. They should be part of the revised LTMS for ISM. • Yes, we should allow severity adjustments. • As most of you know, we have an LTMS Task Force and an active LTMS TF Statistics Subgroup. Our next LTMS TF SS meeting is September 1. I hope to suggest a new LTMS for ISM for consideration at that meeting based on revised LTMS concepts and framework. The LTMS TF could eventually propose new LTMS to this Surveillance Panel.

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