1. Fault definition of Marine diesel engine

Marine diesel engine is a kind of complicated thermal machinery.The working condition is complex and the working condition is bad.Therefore, the use of failure is inevitable.The loss of the specified function of Marine diesel engine is the fault of Marine diesel engine.

The fault of Marine diesel engine includes two aspects:

After the failure of ship diesel engine immediately loss of function of the destructive failure.Such as ship diesel engine burning tile, cylinder and so on.

The performance of the ship diesel engine to reduce the performance of the fault.Such as ship diesel engine smoke, fuel consumption increased.

2. Classification of Marine diesel engine faults

Marine diesel engines can be classified in different ways.

(1) under the specified conditions of use, due to the ship diesel engine and its parts and components of the province's inherent factors or defects caused by the fault becomes an essential fault.Such as Marine diesel engine cylinder liner cavitation corrosion, link fracture.

The misuse fault is known as the misuse fault, which is not used in accordance with the specified conditions or is caused by external factors.As a result of insufficient lubricating oil surface caused by burning tile.

A derivative fault that is caused by a fault with which we are dependent.Also known as related faults.Such as connecting rod bolt fracture caused by the body cracks.

2.1 classification of Marine diesel engine faults according to their severity and harm can be divided into four categories: nominal fault, serious fault, general fault and mild fault.

(1) fatal failure caused by important parts scrapped, resulting in casualties or major economic losses of the fault is known as fatal failure.Also known as hazardous failure.Such as connecting rod bolt fracture, body fracture, etc.

The serious fault where the main performance index of the Marine diesel engine exceeds the limit, the main parts of the damage or disintegration to be able to eliminate the fault is called a serious fault.For example, the oil consumption of Marine diesel engine is too high and piston ring is broken.

(3) general fault ship diesel engine needs to stop maintenance, need to replace the non-main parts, with random tools can be eliminated by the fault is generally known as mild fault.Such as three leakage (leakage, leakage, leakage), cover plate damage.

(4) mild faults generally do not cause ship diesel engine shutdown, do not need to change parts, with random tools in a short time can be removed of the fault is called mild fault.Such as Marine diesel engine seal parts leakage, cover plate screw loose and so on.

2.2 classification of Marine diesel engine according to the speed of fault occurrence according to the speed of fault occurrence, it can be divided into sudden fault and gradual fault.

After the sudden failure of the fault in a short period of time, can not rely on early diagnosis to predict.Such as connecting rod bolt fracture, valve spring fracture.

The occurrence of this fault has a gradual process that can be predicted through early diagnosis.Such as cylinder liner wear, valve leakage, etc.

2.3 classification of Marine diesel engines according to the parts where faults occur, they can be divided into two types: whole-engine faults and parts faults.

Complete machine fault is also known as comprehensive fault.It affects the performance of the whole machine, the reasons are comprehensive.For example, starting difficulty, insufficient power, flying car, unstable speed, abnormal pressure, etc.

The fault for a part is a fault for a part.Such as gear fracture, pump volume is too small.

2.4 classification of Marine diesel engine faults according to their causes and phenomena, they can be divided into three categories: abrasion fault, misuse fault and weakness fault.

After wear fault due to friction pair wear is too large and caused by the fault is called wear fault.This kind of fault can be predicted during normal wear and tear under normal service conditions.Such as piston ring excessive wear, resulting in serious air leakage, power shortage, such as this kind of failure will not cause serious consequences.

The essay misuse fault in actual use, the load is more than the original design ability caused by the fault is known as the misuse fault.Such as overload use of Marine diesel engine caused by black smoke, shafting fracture, etc.

Weak fault in actual use, the load produced by the load does not exceed the design ability, but the design error caused by some weak links, resulting in the failure of parts to lose the ability to work is called weak fault.This kind of failure mostly happens on newly developed models.It is generally manifested as parts damage, shaft system and support fracture.