Fall 1998
|
Fall 1998 |
|
| [ Back ] [ Next ] |
Tannas and Chrysler Develop new TEOST protocol
The Chrysler/Tannas TEOST (Thermo-oxidation Engine Oil Simulation Test) was developed to evaluate engine oils for deposit forming tendencies in high-temperature areas of the engine, especially in the turbocharger. Protocol 33C of the test is currently included in the GF-2 international oil standard.
In preparation for the new GF-3 engine oil category, TEOST developers Ted Selby, R&D Director of Savant, Inc., and Dennis Florkowski of Chrysler Corporation have been focusing their efforts on modifying the 33C protocol to evaluate engine oils at the temperatures found in the piston-ring belt area (around 300°C). As a result of their work during the past five years a new method, TEOSTMHT (moderately high temperature), has been developed.
The TEOST MHT test can be run on TEOST 33C bench test units already in the field, with retrofit hardware and modified test conditions. The primary hardware differences are 1) a glass depositor rod casing instead of steel, allowing for viewing of the oxidation/deposit process, 2) wire-wound depositor rods to permit thin-film oil flow over the heated rod, and 3) collection of volatilized material generated in the depositor rod casing during the test.
The TEOST MHT was developed to correlate with reference oils established for the European deposit test, TU3MH, a Peugeot engine test selected by the ASTM Passenger Car Engine Oil Classification Task Force as the target for evaluating potential GF-3 deposit tests.
After much preliminary work during 1997 and early 1998, a Beta-Test of the near-final TEOST MHT protocol was conducted during May and June. Test conditions are shown in Table 1.
| Tannas and Chrysler Develop new TEOST protocol | |
| Test time | 24 hours |
| Temperature | 285°C |
| Sample size | 10 mL |
| Flow rate (sample) | 0.25 g/min |
| Flow rate (dry air) | 12 mL/min |
| Catalyst | Fe + Pb + Sn |
Six labs using seven different operators and units participated in the Beta-Test to determine preliminary precision of the method and correlation with TU3MH reference oils. The three oils used in the Beta-Test were characterized on the TU3MH test as Pass Plus (Oil A), Borderline (Oil B) and Fail (Oil C). Labs were asked to report the weight of deposits on the rod and in the combined washing residue from the rod, mantle and end caps.
As shown in Table 2, there was good separation and ranking of the reference oils and surprisingly good repeatability and reproducibility in this early round of interlaboratory testing.
| Results of TEOST Protocol MHT Beta-Test | ||||||
| Lab | Rod and Filtered Rod Washings Weight (mg) | |||||
| Oil A | Oil B | Oil C | ||||
| Run 1 | Run 2 | Run 1 | Run 2 | Run 1 | Run 2 | |
| 1 | 14.4 | 11.70 | 53.70 | 56.2 | 112.60 | 120.20 |
| 2 | 12.5 | 10.80 | 56.60 | 59.6 | 106.80 | 113.60 |
| 3 | 12.0 | 12.50 | 68.50 | 71.0 | 106.80 | 101.50 |
| 4 | 6.3 | 5.60 | 50.40 | 51.4 | 123.10 | 119.10 |
| 5 | 13.7 | 14.10 | 62.60 | 56.5 | 120.30 | 125.80 |
| 6 | 11.9 | 19.20 | 61.90 | 55.9 | 121.50 | 120.50 |
| 7 | 7.8 | 13.7 | 61.9 | 53.30 | 123.20 | 115.70 |
| Average | 11.87 mg | 58.49 mg | 116.48 mg | |||
| Standard Deviation | 3.52 mg | 6.08 mg | 7.28 mg | |||
| % Standard Deviation | 29.62 | 10.39 | 6.25 | |||
During August and September ASTM is conducting a precision matrix study, running nine industry oils on both the TEOST 33C and TEOST MHT protocols. Results of the matrix testing will be used to further evaluate the precision of the tests and their applicability to the new engine oil category.
| [ Back ] | [ Next ] |