Nitration - Lubricating Oil Analysis
Nitration products are formed during the fuel combustion process when combustion by-products enter the engine oil during normal operation or as a result of abnormal "blow-by" past the compression rings. These products, which are more common in oils used to lubricate natural gas- and propane- fueled engines, are highly acidic, create deposits, and accelerate oil oxidation. Infrared analysis represents the only method of accurately measuring nitration products in oil. Results are reported on an absorbance scale.
Cause
• Improper crankcase scavenge
• Low operating temperature
• Defective seals
• Improper air/fuel ratio
• Abnormal blow-by
Effect
• Accelerated oxidation
• Nitrous oxides introduced into environment
• Acidic by-products formed
• Increased cylinder and valve train wear
• Oil thickening
• Combustion chamber deposits
• Increased acid no.
Solution
• Increase operating temperature
• Check crankcase venting hoses and valves
• Ensure proper air/fuel mixture
• Perform compression check or cylinder leak-down test
