Polyalkylene Glycol - piston ring cleanliness

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JAG

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This is from Castrol around year 2000.

http://www.wipo.int/pctdb/en/wo.jsp?IA=WO2000023544&DISPLAY=DESC
Quote:
Two of the criteria measured in the Voikswagen TDi test are piston cleanliness and ring sticking. Piston cleanliness and ring sticking are measured in accordance with industry approved rating methods such as CEC M-02-A-78 for ring sticking and DIN 51 361 Part 2 for piston cleanliness.

The VW TDi test first became available in late 1996. It was included in the 1998 update of the ACEA specification to compliment the existing indirect injection diesel test based on the VW 1.6 litre intercooled turbo diesel engine (PV1431 or CEC L-46-T-93). The new test is significantly more severe than the PV1431 test in the areas of increased overall oil temperature (+15°C) and top piston ring zone temperature (+40°C).

Oils developed for the PV1431 test may not be robust enough for the new test.

Standard engine oils run in the TDi test often give poor piston cleanliness and severe ring sticking results as they are not designed to protect these parts at these elevated temperatures. Severe ring sticking often leads to increased blow-by rates which in turn leads to increased oil consumption. In some cases almost 100% of the sump fill can be consumed during the test, resulting in complete engine failure.

An oil that is suitable for a direct injection engine will be suitable for an indirect injection engine. The reverse is not always true.

There are well-known methods for improving diesel engine performance in terms of piston cleanliness; however, the need to adhere to other industry specifications often limits the extensive use of these methods. For example, one method is to increase the level of sulphated ash in an oil formulation. However, ACEA and Volkswagen specifications allow only a maximum amount of 1.5% mass sulphated ash in passenger car motor oils.

A further method for improving diesel engine performance is to increase the level of ashless dispersant additive used in the oil. Unfortunately, increasing the level of ashless dispersant additive in the oil can lead to a significant derating of performance in the Volkswagen elastomer test, which is part of the current Volkswagen PCMO (Passenger Car Motor Oil) specifications. Increasing the level of ashless dispersant additive can also lead to poor cold-temperature performance, which will make it more difficult to blend low viscosity oils.

It doesn't take much PAG:
Quote:
he polyalkylene glycol is preferably used in an amount less than 3% by mass, more preferably in an amount less than 1% by mass, and most preferably in an amount between 0.1% to 0.5% by mass.

The results at the end have terrible format. If someone can translate it into understandable format, please do!
 
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