Posted by : sanjay swain Saturday, August 15, 2015

Diesel Engine Exhaust Turbocharger Failure 

Turbochargers are among the foremost technologically advanced engine element aboard ship. impeller blades of a medium sized turbocharger often rotate at the maximum amount as 400 revolutions per second. The outer edges of the rotor blades therefore move at 1.5 times the speed of sound.

In the method, the turbocharger digests contaminated exhaust gases of up to 700 degrees centigrade. Thus, the turbocharger may be a terribly sensitive piece of high-speed machinery incessantly serving in harsh conditions and underneath extreme strain. Being on the receiving end of gas flows, turbocharger damages are typically caused by the failure of varied upstream elements.

(1) Diesel engine inlet pressure to reduce main reasons:
(a) the compressor of the filter contamination.
(b) the impeller and vanes diffuser contamination.
(c) the supercharger turbo memory have more carbon deposit, spin resistance increase.
(d) the inter-cooler contamination, increased intake resistance.
(e) turbine exhaust not clear, this is because the pipe blockage, deformation caused by rotor speed rise is  not high.
(f)supercharger outlet pressure drop suddenly, it is because of bearing damage caused by.

(2) Compressor surge main reasons:
(a) diesel engine emergency cut-off or sudden unloading (urgent throttle back).
(b) the atmospheric temperature changes cause surge. In the summer of the supercharger with test, in winter could happen surge, this is because the temperature change make working point change and cause.
(c) compressor contamination, especially vanes diffuser contamination.
(d) a engine plant 2 sets of supercharger, Shared a piece of inlet manifold, when a cylinder does not work, can lead compressor surge.

(3) Diesel engine inlet pressure is too high. Generally speaking, the inlet pressure is too high in the supercharger itself is not the problem, but by the engine of the cause, the main reasons are:
(a) the vent valve leakage.
(b) because of engine fuel injection timing inappropriate or other causes for combustion period is too long, to drive a turbine heat increase, speed up, inlet pressure increase.

(4) Produce continuous abnormal sound: this kind of failure is due to the majority of rotor and shell as a result of the collision. Due to the rotor and shell assembly clearance is small, if installation misadjustment or bearing serious damage, then hitting.

(5) The lubricating oil temperature is too high (above 105 ℃) of the main reasons:
(a) the turbine oil, gas seal damage, high temperature gas into the oil chamber.
(b) the bearing damage.

(6) Oil leakage: compressor seal close to the edge of the impeller is low pressure area, easy to produce the oil leakage fault. Main reasons are:
(a) the lubricating oil return not free. The reason has return line congestion, return line sectional area is too small, pipe joint gasket inner hole diameter less than return line; Diesel engine in the crankcase oil level higher than standard, cause oil return difficult; Diesel engine crankcase ventilation blocking or cylinder seal bad, gas expell, make the crankcase internal pressure rise.
(b) the compressor end O ring damage or material ageing and lose sealing effect.

(c) turbocharger oil inlet pressure is too high. Normal pressure is 0.25 ~ 0400000 mpa, if pressure is higher than 0.6 million mpa, from exhaust muffler nozzle will find from the supercharger turbo end leakage oil.
(d) ring not installed correctly or damage.


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