The Importance of Accurate Dilution Calculation in Engine Diagnostics

When we look for wear we want to measure the concentration of iron (and other elements) in the cylinder lubricating oil dripping from the rim of the liner (allowing for contamination by unburnt fuel).

Diagram of dilution of PPM in the underpiston space

Once the cylinder oil reaches the underpiston space, it becomes mixed with system oil, unburnt fuel and water amongst other materials. The original proportion of cylinder oil can be diluted many times (see above) giving a highly misleading picture of the value of the elements from the cylinder oil. Exactly the same situation occurs to system oil carrying copper wear debris from the stuffing box.

Fundamentally, dilution means that you cannot trust the drain oil measurements that you read in the laboratory test results, or onboard test kits, have any relation to the cylinder lubricator oil dripping from the rim of the liner. In order to make any sense of the drain oil measurements, you must calculate the various proportions; and this is complex.

FlameADT (Advanced Dilution Theory) is a unique and sophisticated software model that has been developed over the last 7 years by Flame Marine and has been validated in Flame Diagnostic since 2007 (and latterly FOBAS Engine). FlameADT calculates and corrects for these dilutions by running tens of thousands of simulations to model the impact of the various factors.

Knowing the proportions of the individual components of the drain oil gives essential information about the operating condition of the engine;

  • Wear conditions and type of wear
  • Reliable estimation of the amount of acid being produced by the burning of the fuel
  • Quality & Cleanliness of combustion
  • Environmental Compliance
  • Condition of Piston and Rings
  • Correct cylinder lubricant feed rate
  • Fuel efficiency

Within Flame Diagnostic and FOBAS Engine, this information is used either directly to report on a phenomenon such as wear or in combination with other assessments to reach the conclusions in the report. In many cases, the conclusions reached are supported by other independent measurements or assessments and thereby validate the overall conclusions using the principle of 'dual-phenomena'.

FlameADT is one of a suite of advanced software algorithms used by Flame Diagnostic and FOBAS Engine to give you the most accurate diagnosis of the operation of your engine available today.

Cylinder Lubrication Oil Feed and Measurement location
Cut away diagram depicting a cylinder in a 2 stroke marine engine. The small red arrow refers to the direction of lubrication oil from injection to measurement.