320mm an 460mm bore diesel engine turbo charger issue

[redlinej]

Hi guys,

working with diesel engine of 320 mm and 460 mm, I observed that after doing maintenance on the turbo(replace cartridge and new nozzle ring and cleaning) the outlet temperature(stack) of turbo is very high.The problem goes away after a week of running the engine at maybe 60 to 100 percentage load.

The explanation I got for this, from a turbo specialist, is that the blade is too clean and the exhaust gases is escaping because of the smoothness of the blade.This make sense to me, but was wondering if the is more physics to it.

 

[MikeHalloran]

i.e., it takes a while for turbo gas passages to get coked up enough to reduce the blade/volute clearance to some optimal dimension so the gas is forced to travel along the blades, and only a little goes around them.

... and maybe it takes that long for the cartridge bearing to 'wear in' and reduce its friction torque.

Either way, the high stack temp suggests that the turbo is turning too slowly for best performance.

Turbos work by extracting heat from the exhaust gas flow.
When they're running right, the stack temperature is a lot lower than the exhaust manifold temperature.




Mike Halloran
Pembroke Pines, FL, USA