Seven Common Turbocharger Failures & Their causes.
- Abnormal vibration and noise of Turbocharger
The Turbocharger produces abnormal vibration and noise, which directly affects the service life of the Turbocharger. The main reasons are: the Turbocharger rotor shaft is bent and deformed or the blades are deformed, and the bearing is damaged, causing the gap between the outer arc of the impeller and the casing to disappear, causing friction. Carbon deposits on the rotor lead to a decrease in dynamic balance accuracy and partial leakage in the pipeline connected to the Turbocharger.
- Poor boosting effect
The main manifestations are reduced power, black smoke, blue smoke, poor fuel economy, and significantly excessive fuel consumption. There are three reasons for this: The air filter is too dirty and cannot provide high-density clean air to the engine. The impeller is damaged, causing insufficient air intake. There is too much dust in the intake air, and there is sludge at the joint between the impeller and the Turbocharger housing, which affects the speed of the Turbocharger impeller and causes insufficient air intake.
- Turbocharger surge
In addition to compressor surge caused by improper matching between the Turbocharger and the diesel engine, a well-matched Turbocharger may still experience surge when operating conditions change. The root cause is reduced air flow from the compressor.
- Oil leakage from one or both ends of the Turbocharger
This is a relatively common fault and the main reason that affects the service life of the Turbocharger. The Turbocharger rotates at high speed, and its floating bearings are lubricated by lubricating oil in the oil pan. After the oil that enters the bearing gap at normal pressure passes through the bearing working surface, the oil pressure becomes zero and flows back to the oil pan by its own gravity and will not flow out from both ends of the Turbocharger. During normal operation, there is a certain pressure between the two impellers of the Turbocharger, and the oil will not flow from the low-pressure bearing area to the high-pressure areas at both ends. There are sealing rings and floating bearings between the two impellers. Oil leakage may occur, but may occur from both ends of the Turbocharger under the following conditions.
① The air filter is too dirty or clogged
When the air supply to the air filter is poor due to excessive dust or other reasons, the negative pressure at the air inlet of the compressor will be too high, causing the internal pressure at one end of the compressor to be higher than the external pressure, and the oil will flow from the inlet under the action of the pressure difference. Tracheal outflow. One end flows out.
② Floating bearing wear
If the oil is not changed for a long time or the air filter fails, too much dust will enter the Turbocharger, and the floating bearing will be severely worn, resulting in excessive bearing clearance and unstable oil film. At highway speeds, a Turbocharger can quickly become unbalanced. The vibration of the rotor shaft system intensifies, destroying the seals at both ends, causing lubricating oil to leak.
③ Long-term idling of the engine will also cause oil leakage from the Turbocharger
When the engine idles for a long time, negative pressure will be generated behind the turbocharger turbine and compressor impeller, causing the oil flowing out of the floating bearing to leak out under the action of the pressure difference.
④ Poor oil return
When the oil flows out of the floating bearing of the Turbocharger, it flows back to the oil pan by its own gravity. But when the oil return pipe is deformed or clogged, or the exhaust pressure in the crankcase is too high, causing pressure in the oil return pipe, the oil flowing out from the floating bearing will not flow back to the oil pan smoothly, and will flow out along the rotor shaft. The sealing rings at both ends flow out, causing oil leakage.
- Turbocharger speed is too high
The reason for the high speed of the Turbocharger is that the energy at the turbine inlet is relatively high or the load of the compressor is relatively low.
- Exhaust temperature is too high
Excessive exhaust temperature will affect the life of the turbine. The reason is serious cylinder afterburning. It may be that the boost pressure is too low and there is insufficient air in the cylinder. Too big to wait.
- Low boost pressure
Low boost refers to compared to normal (pressure is less than 90% of normal). Low boost pressure will reduce the amount of air charge in the cylinder, which will not only reduce the power of the diesel engine, but also worsen the combustion process in the cylinder and increase fuel consumption and exhaust temperature.
As the requirements for automobile exhaust emissions become more and more stringent, automobiles have become polarized. Some are developing in the direction of new energy, including electric and hybrid vehicles; the other is developing in the direction of small-displacement vehicles, but small-displacement vehicles Volume means power difference, so a turbocharger is installed on the engine to achieve small displacement and high power.
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Carlpillar Turbo
