It may sound gross, just as doctor advise to pay attention to your poop as bowel movements are a pretty good indicator of your digestive health. The same goes for the exhaust temperatures of the engine. It is one of the most important parameters to observe during rounds and especially before putting the vessel to UMS mode. Any abnormal deviation is a sure indication of any abnormalities in the system, best practice would be to investigate and rectify the issue before putting the engine in use.
The exhaust temperature of the different units may be slightly varying due to design factors, distance from the turbocharger inlet, exhaust grouping, design of inlet air manifold, etc.
The acceptable difference between cylinder may be less than 40deg cel or the value specified by the manufacturer.
Generally, there are two types of abnormality that may occur
The exhaust temperature of the different units may be slightly varying due to design factors, distance from the turbocharger inlet, exhaust grouping, design of inlet air manifold, etc.
The acceptable difference between cylinder may be less than 40deg cel or the value specified by the manufacturer.
Generally, there are two types of abnormality that may occur
- All cylinders abnormal.
- Any-one or some cylinders abnormal.
Note always check thermometer are not faulty and the indicator valve is not clogged
High exhaust temperature in all units
- Increase in engine load due to hull fouling, bad weather, damage to propeller blades,,etc.
- Improper fuel qualities, fuel viscosity decrease in fuel temperature.
- Fouling of scavenging air side due to oil mist, clogged air coolers.
- Fouling of exhaust air passage, due to build up in turbocharger nozzles and increase in exhaust gas backpressure restricting the efficient removal of exhaust gas.
- Inefficient blower due to clogged suction filters.
- Leakage of scavenging air between the blower seal leading to inefficient scavenging.
- Fire in scavenge space and under piston area.
- Exhaust valve timing problem.
- Problems in the governor.
High exhaust temperature in any one unit/some units
- Excessive large fuel injection due to improper fuel rack setting or fuel rack stuck in a position.
- Defective fuel injection valve due to a defective nozzle or improper opening pressure.
- Leaks in the exhaust valve due to damage in the exhaust valve seat due to wire drawing effect.
- Improper tappet clearance.
- Piston blow past leading to a decrease in peak pressure, hence improper combustion which may lead to higher exhaust temperatures.
Safeties
Some engine may /may not have the following safties depending on the manufacturer
- Alarm for hight exhaust gas deviation
- Slow down for high exhaust temperature
In an emergency situation-cancel slow down can be activated to bypass the slowdown
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