TS-32
RESEARCH FOR ABNORMAL CONDITION DIAGNOSIS ON DIESEL ENGINE
Takaaki Shimizu*
ABSTRACT
The common theme of shipping, industry is to detect abnormal condition of the diesel engine in an early stage and to prevent it from vital accidents for increasing the Safety and the Operation rate of the ship. Although various abnormal condition diagnosis devices have been developed up to the present, in all cases, temperatures and pressures of various parts of the engine are detected and engine performance is estimated and the abnormal condition diagnosis is performed by the Artificial Intelligence (AI). Therefore, the accuracy of abnormal condition diagnos is not always satisfactory. For the analysis of engine operating performance, the combustion analysis system, etc., have also been developed. However, at present, these systems are not fit for actual circumstances from the point of view of sensor's durability, etc.
In case of the diesel engine, as Gas pressure in cylinder will act on the crankshaft via the piston and connecting rod and is converted into the rotary force.
In this paper, the author would like to introduce way of the abnormal condition diagnosis which by the observation of Torque fluctuations (Torsion angles) of the crankshaft. We put a detecting device for the crankshaft torsion angles to the test, and validated that approach.
Key Words: Abnormal Condition, Diagnosis, Diesel Engine, Safety, Torsion Angle
1.INTRODUCTION
Recently almost industries try every possible means to reduce the cost. Of course shipping industry too, and it is natural that reducing the cost depends on increasing the operation rate of the ship.
Therefore abnormal condition diagnosis (detected abnormal condition of the diesel engine in early stage and to prevent it from vital accidents) drew the attention. Although various abnormal condition diagnosis devices have been developed up to the present, in all cases, temperatures and pressures of various parts of engine are detected and engine performance is estimated and the abnormal condition diagnosis is performed by the Artificial Intelligence.
Therefore, the accuracy of abnormal condition diagnosis is not always satisfactory because of disturbance. For the analysis of engine operating performance, the combustion analysis system, etc., have also been developed. However, at present, these systems are not fit for actual circumstances from the point of view of sensor's durability, etc.
In case of diesel engine, as Gas pressure in cylinder is detected by the observation of Torque fluctuations (Torsion angles) of the crankshaft, the increased of accuracy of abnormal condition diagnosis of the diesel engine is intended to.
2. THEORETICAL BACKGROUND
2.1 Theoretical relation between the torque fluctuations and the gas pressure in cylinder
2.1.1 Torque wave of the crankshaft
As shown Fig. 1, the Torque action on the crankshaft can be obtained by the following formula.