Originally Posted by JAG
Infineum's statement in the article is:
"The effect of calcium and magnesium based detergents on LSPI has already been the subject of Infineum studies. Calcium-based detergents have been shown to strongly promote LSPI while magnesium-based detergents appeared to have nearly no effect on LSPI. However, various calcium and magnesium concentrations have been observed to have no statistically measurable difference in the IQT for gaseous fuel/oil/air auto-ignition."
They don't define what the various concentrations were. Since we don't know and the second sentence says calcium strongly promotes LSPI, I think it's not prudent for us to think that we don't need to have much concern about how much calcium is in oils.
That's what I was saying earlier...they state that it's a strong correlation in the engine test, but that it doesn't show in their "cetane test" (which is what their test is based on, diesel engine cetane.
As a result, I think that their decision to test the cetane (autoignitability) of the oil is a poor proxy for LSPI, and not correct.
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The IQT-measurement, which is based on an ASTM method (D6890), required several repeat tests.
https://www.astm.org/DATABASE.CART/HISTORICAL/D6890-08.htm
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1.1 This automated laboratory test method covers the quantitative determination of the ignition characteristics of conventional diesel fuel oil, oil-sands based fuels, blends of fuel containing biodiesel material, diesel fuel oils containing cetane number improver additives, and is applicable to products typical of ASTM Specification D 975 grades No. 1-D and 2-D regular and low-sulfur diesel fuel oils, European standard EN 590, and Canadian standards CAN/CGSB-3.517 and 3.6-2000. The test method may also be applied to the quantitative determination of the ignition characteristics of diesel fuel blending components.
1.2 This test method measures the ignition delay and utilizes a constant volume combustion chamber with direct fuel injection into heated, compressed air. An equation correlates an ignition delay determination to cetane number by Test Method D 613, resulting in a derived cetane number (DCN).
1.3 This test method covers the ignition delay range from 3.3 to 6.4 ms (61 to 34 DCN). The combustion analyzer can measure shorter and longer ignition delays, but precision may be affected. For these shorter or longer ignition delays the correlation equation for DCN is given in Appendix X2. There is no information about how DCNs outside the 34 to 61 range compare to Test Method D 613 cetane numbers.
You can't claim both
* real world and test engine experience shows a strong correlation to Calcium
* that our (non engine test) refutes that, being insensitive to Calcium
* the findings of our (non engine tests) accurately reflects the effect of basestock on LSPI.