Phosphorus Emission Index (PEI) Studies Of ZDDP in Engine Oils

1. Phosphorus Emission Index (PEI) Studies Of ZDDP in Engine Oils ESCIT Meeting, 2006 August 8 At Toyota Technical Center Ann Arbor, Michigan Presented by: Ted Selby, Savant, Inc.

2. Air Inlet Air Inlet Vacuum Monitor Vacuum Temperature Sensor Temperature Sensor and Controller and Controller Reaction Flask Top & Bottom Test Oil Test Oil Noble Metal Heater & Insulation Volatiles Collection Vessel Filter & Drain PEI as a measure of phosphorus volatility and catalyst response Background of Present Work The PEI technique was developed from analysis of the volatiles from engine oils containing ZDDP using an instrument developed by Savant Labs and designed by the Tannas Co. Vacuum Monitor Vacuum Reaction Flask Top & Bottom Noble Metal Heater & Insulation Volatiles Collection Vessel Filter & Drain

3. PEI as a measure of phosphorus volatility and catalyst response Background of Present Work (cont.) The Phosphorus Emission Index or PEI is a measure of phosphorus volatility from engine oil in milligrams/Liter. PEI = mgP / Loil In first studies, the PEI protocol was applied for one hour at 250°C (approximately ring belt temperatures). Using data from the Institute of Materials database on several thousand engine oils, it was found that there was no correlation between phosphorus volatility and 1. Volatility of the engine oil in the Noack test, or 2. Initial concentration of phosphorus

4. PEI as a measure of phosphorus volatility and catalyst response Background of Present Work (cont.) Following these initial studies, the question was raised by Ford Motor Co. as to whether PEI250 would correlate with catalyst deposition and exhaust gas characteristics. Limited information from taxi fleet tests by Ford and Afton Chemical Co. showed such correlation ….

5. PEI as a measure of phosphorus volatility and catalyst response Background of Present Work (cont.) Correlation was based on four values and also showed effects of other additives in the oils …. …. as well as the effects on emissions ….

6. PEI as a measure of phosphorus volatility and catalyst response Background of Present Work (cont.) Correlation of PEI with NOx / Mile.

7. PEI as a measure of phosphorus volatility and catalyst response Background of Present Work (cont.) Following these initial studies, the question was raised by Ford Motor Co. as to whether the PEI would correlate with catalyst deposition and exhaust gas characteristics. Limited information from taxi fleet tests by Ford and Afton Chemical Co. showed such correlation. More recently, cooperative work between the Savant Labs and ICL-PPLP has also shown information on the mechanism of ZDDP decomposition particularly for ….

8. PEI as a measure of phosphorus volatility and catalyst response Background of Present Work (cont.) 1. Different ZDDP chemistries using PEI250

9. PEI as a measure of phosphorus volatility and catalyst response Background of Present Work (cont.) 2. Different temperatures (one hour exposure time)

10. PEI as a measure of phosphorus volatility and catalyst response Background of Present Work (cont.) 3. Different exposure time at a given temperature.

11. PEI as a measure of phosphorus volatility and catalyst response Recent Work On the basis of the foregoing time exposure work, PEI165 values were determined at 16 hours using a co-volatile SN75 base oil and this became an experimental protocol. Since past information gathered with PEI250 had shown literally no correlation with base oil volatility, it was considered that the use of a co-volatile should not influence the volatilization of phosphorus. However, to meet any questions regarding this approach, PEI165-16 values of two GF-4 engine oils were determined with and without use of a co-volatile. Results confirmed expectations that a co-volatile would not influence the value of PEI165-16 obtained ….

12. PEI as a measure of phosphorus volatility and catalyst response Recent Work (cont.) No significant effect of a co-volatile on PEI165 values.

13. PEI as a measure of phosphorus volatility and catalyst response Summary of Background Lack of correlation between phosphorus content of the engine oil and phosphorus volatility was shown by a bench test (PEI250) which, in contrast, showed interesting correlation with catalyst deposition of limited field tests. Later, studies of different types of ZDDP showed clear differences between their decomposition mechanisms. Versatility of the PEI method permitted extending these studies to other temperatures and volatilization exposure intervals with the result that other characteristics of phosphorus volatility became evident using NMR methods. More data was requested in applying this test method to engine, catalyst, and emission studies to further develop correlation and understanding of the causes and control of phosphorus volatility using engine operating temperatures.

14. PEI as a measure of phosphorus volatility and catalyst response Present Work As temperature is reduced at which information is sought from the PEI protocol, more attention must be paid to the assurance of gathering sufficient sample in the instrument’s Collector. Considerable interest has developed in applying higher and lower PEI temperatures, especially in the normal to hard engine operating range. For the lower range, a PEI120 protocol was very recently developed and applied. For such lower temperature, it was anticipated that a fairly light hydrocarbon co-volatile would be required and analytical-grade kerosene was chosen.

15. PEI as a measure of phosphorus volatility and catalyst response Present Work (cont.) First work at 120°C used the 16-hour protocol (PEI120-16), and gave sufficient sample for analysis., also led to a more extended 48-hour, 120°C technique. It was thought to be of value to apply an extended 48-hour, 120°C technique (PEI120-48) that would provide opportunity to gain more information about phosphorus volatility. The 48-hour technique was periodically interrupted for small, half-gram samples on which PEI120 values at several exposure periods could also be determined thus giving a PEI ‘time and decomposition scan’ at the temperature chosen. Both techniques worked well and will be again part of the effort to develop correlation with field tests. Very preliminary information is promising but requires study of precision of the new techniques.

16. PEI as a measure of phosphorus volatility and catalyst response Future Work Such preliminary work at 120°C may provide a higher level of PEI precision than at higher temperatures. However, this precision remains to be shown with replicate studies. The same may be said of coming work at temperatures of 150° to 165°C and the study of the decomposition products of such PEI analyses through NMR techniques. Correlation of the PEI protocols with engine data both on the dynamometer as well as in the field remains at a high level of interest for OEMs and additive suppliers. Promising cooperative work with both OEMs and others is underway with correlative data that will, with hope, be soon available and directive regarding a bench test for phosphorus volatility. From very recent studies the two temperatures of 120° and 150°-165°C have emerged as being of interest and specific PEI protocols developed for application to engine studies.