Wednesday, July 1, 2020

Overheating of Main Engine Piston

Reasons: 
  • Inadequate circulation of cooling media and or supply not sufficient
  • Excessive deposit in cooling space (scale or carbon)
  • Lubrication not sufficient
  • Faulty piston ring : clearance inadequate. 
  • Too high temperature 
  • top ring groove area – blow by.
  • Distorted cylinder liner
  • Misalignment of piston
  • Overloading of unit – excessive fuel
  • Excessive water content in fuel
  • Insufficient air from turbocharger or manifold
  • Late injection of fuel – timing or fault injectors
  • Engine running slow speed – full flow of coolant not maintained
Action:
  • Slow down the engine to a very low speed but NOT complete shutdown. This results in considerable reduction of heat in the relevant piston.
  • Since not all pistons would likely develop this fault simultaneously (unless you are totally out of luck that day) so first identify the particular cylinder in which the problem has occurred using parameters such as temperatures, sound etc.
  • The fuel supply to the affected cylinder should be cut-down from the fuel pump
  • Lubrication to that cylinder should be increased from the appropriate arrangement depending on the specific engine under consideration
  • Only stop the engine when it is sufficiently cooled to avoid any thermal stresses. Even after stopping the turning gear should be used to keep it moving for some time while cooling and lubrication is continued.
  • Finally the piston needs to be dismantled and checked and this is a detailed procedure which we might take up in future

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