Oxidation in Diesel engines 1

[mtmcall]

Why am I seeing oxidation levels rise in our new EGR-DPF engines. Levels have risen about 6%-8% versus just an EGR engine. We are using the new CJ4 oils from a major supplier. Any advice is welcome and Happy Holidays

 

[romke]

how have you reached the conclusion that oxidation levels have gone up? when you use a new engine with a new engine oil the values you will find when doing a used oil analysis will differ somewhat from the igures you were used to.

 

[mtmcall]

Romke,

Through Oil Analysis. We sample every 12K. Our units with the DPF have 200K on them. We did not se this using CI 4plus engine oils. Since we have 120 units on CJ 4 we made the move over to the whole fleet. No other levels have increased. My concern is what effects is oxidation or increased oxidation going to have on engine life

 

[Demon3]

Hello. It is not clear to me how you are quantifying the oxidation level. How does the method work? There are many ways to do say and they could give you varying results.

FTIR can be used to quantify oxidation by looking at the carbonyl peak that grows as oxidation increases

Differential scanning calorimetry (DSC) can be used whereby you heat the oil under oxygen at high temperature and wait for an exotherm (heat output).

What the previous poster is getting at is that you need to understand how the method works before you can say whether the results between two oils can be compared fairly.


Chris DeArmitt

 

[romke]

as i understand it you have changed two things at once - new engines with a DPF and a new (lowSAPS) engine oil. both can have an influence on what you find carrying out an analysis. to make things more complex still, the fact that you find higher values for oxidation now does not necessarily mean that the life expectancy of oil and/or engine has to be lowered. what you should be aware of is that the oil you use now is quite different in composition as the previous one, not only in additive chemistry (lowSAPS) but also most likely in the baseoil used. also the engines have problably changed somewhat to accomodate the DPF, which may have lead to higher internal temperatures in some areas and may have increased the tendency of an oil to get oxidized. did you talk to the engine manufacturer or the lubricant supplier about your indings? they know what has changed in their respective components and might be able to give some useful comments.