ASTM D7156 Standard Test Method for Evaluation of Diesel Engine Oils in the T-11 Exhaust Gas Recirculation Diesel Engine
11. Laboratory and Engine Test Stand Calibration /Non-Reference Oil Test Requirements
11.1 Calibration Frequency - To maintain test consistency and severity levels, calibrate the engine and test stand at regular intervals.
11.2 Calibration Reference Oils - The reference oils used to calibrate T-11 test stands have been formulated or selected to represent specific chemical types or performance levels, or both. Obtain the reference oils from the TMC. The TMC will assign reference oils for calibration tests. These oils are supplied under code numbers (blind reference oils).
11.2.1 Reference Oils Analysis - Do not submit reference oils to physical or chemical analyses for identification purposes. Identifying the oils by analyses could undermine the confidentiality required to operate an effective blind reference oil system. Therefore, reference oils are supplied with the explicit understanding that they will not be subjected to analyses other than those specified within this procedure unless specifically authorized by the TMC. In such cases where analyses are authorized, supply written confirmation of the circumstances involved, the data obtained, and the name of the person authorizing the analysis to the TMC.
11.3 Test Numbering - Number each T-11 test to identify the test stand number, the test stand run number, engine serial number, and engine hours at the start of the test. The sequential stand run number remains unchanged for reruns of aborted, invalid, or unacceptable calibration tests. However, follow the sequential stand run number by the letter A for the first rerun, B for the second, and so forth. For calibration tests, engine hours shall be zero. For non-reference oil tests, engine hours are the test hours accumulated since last calibration. For example, 58-12A-2H0380-0 defines a test on stand 58 and stand run 12 as a calibration test that was run twice on engine 2H0380 (serial number). A test number of 58-14-2H0380-252 defines a test on stand 58 and stand run 14 as a non-reference oil test on engine 2H0380, which has run 252 h since the last reference.
11.4 New Laboratories and New Test Stands:
11.4.1 A new laboratory is any laboratory that has never previously calibrated a test stand under this test method, or has not calibrated a test stand within one year from the expiration of the last calibration period at that laboratory. All stands at a new laboratory are considered new stands.
11.4.2 A new stand is a test cell and support hardware that has never previously been calibrated under this test method, or has not been calibrated within a year from the expiration of the last calibration period on that stand.
11.4.3 Calibrate a new test stand in accordance with the Lubricant Test Monitoring System (LTMS). Generally, new test stands require two successful calibration tests. However, provisions do exist within the LTMS to allow new stands to calibrate with one test, based upon previous test experience within the laboratory.
11.5 Test Stand Calibration:
11.5.1 Test Stand Calibration - Perform a calibration test on a reference oil assigned by the TMC after 1512 non-reference oil test hours or after six months have elapsed since the completion of the last successful calibration test. An unsuccessful calibration test voids any current calibration on the test stand. A non-reference oil test may be started in a test stand provided at least 1 h remains in its calibration period.
11.5.2 Test Engine Rebuild - A newly rebuilt test engine does not require a calibration test. Run a break-in after a rebuild. The timing and frequency of engine rebuilds is left to the discretion of the laboratory.
11.5.3 If non-standard tests are conducted on a calibrated test stand, the TMC may require the test stand to be recalibrated prior to running standard tests.
11.5.4 The TMC may shorten or extend calibrations at their discretion.
11.6 Test Results - The test results are Soot Content at 4 mm2/s Viscosity Increase (percent), Soot Content at 12 mm2/s Viscosity Increase (percent), Soot Content at 15 mm2/s Viscosity Increase (percent), and MRV Viscosity (pascals seconds).
11.6.1 Use linear interpolation for calculating soot contents (at a given viscosity increase), using new oil 90-pass DIN shear viscosity result as the minimum viscosity (see 10.1.1 and 10.1.5).
11.6.2 Correction Factors:
11.6.2.1 Soot Content at 12 mm2/s Viscosity Increase - For all tests using top ring Part Number 349GC3107 and finishing from September 14, 2005 through December 5, 2005, add a correction factor of -0.39 % to the original test result. For all tests finishing from December 6, 2005 through March 23,2006, add a correction factor of -0.36 % to the original test result. For all tests finishing on or after March 24, 2006, add a correction factor of -0.35 % to the original test result. Report both the correction factor and the final result on the appropriate form.
11.6.2.2 MRV Viscosity - For all tests using top ring Part Number 349GC3107 and finishing from September 14,2005 through December 5, 2005, add a correction factor of 1274 Pa·s to the original test result. For all tests finishing from December 6,2005 through March 23, 2006, add a correction factor of 0.713 Pa·s to the original test result. For all tests finishing on or after March 24, 2006, add a correction factor of 0.956 Pa·s to the original test result. Report both the correction factor and the final result on the appropriate form.
11.7 Reference and Non-Reference Oil Test Requirements:
11.7.1 All operationally valid tests shall produce a TGA soot level of (2.75 +/- 0.25) % at 96 h, (5.50 +/- 0.35) % at 192 h, and (6.53 +/- 0.44) % at 228 h. Any test which misses any of these soot windows is considered operationally invalid. A laboratory should terminate a test that has missed any soot windows. Additionally, all operationally valid tests shall not exceed an oil consumption of 65.0 g/h.
11.7.1.1 Adjust injection timing anytime to meet the three soot windows. Do not change injection timing after 228 h. As a guideline, do not change injection timing more than +/- 3° from the initial injection timing.
11.7.2 Calibration acceptance is determined in accordance with the Lubricant Test Monitoring System (LTMS) as administered by the TMC.
11.8 Non-Reference Oil Test Result Severity Adjustments - This test method incorporates the use of a Severity Adjustment (SA) for non-reference oil test results. A control chart technique, described in the LTMS, has been selected for identifying when a bias becomes significant for any of the following test results: Soot Content at 4 mm2/s Viscosity Increase (percent), Soot Content at 12 mm2/s Viscosity Increase (percent), Soot Content at 15 mm2/s Viscosity Increase (percent), and MRV Viscosity (pascal seconds). When calibration test results identify a significant bias, determine a SA according to LTMS. Report the SA value on the appropriate form. Add this SA value to non-reference oil test results, and enter the adjusted result in the appropriate space. The SA remains in effect until a new SAis determined from subsequent calibration test results, or the test results indicate the bias is no longer significant. Calculate and apply SAs on a laboratory basis.
