Analysis Of Influence Factors On Marine Diesel Engine Crankshaft Deflection And Study Of Digital Measuring Instrument

The crankshaft of marine diesel engine is one of the important moving components. In the crankshaft installation and operation management, the crankshaft alignment of the diesel engine is crucial to its safe operation. Especially, diesel engine as ship propulsion device, its role is irreplaceable. Once the crankshaft out of order, that will be likely to endanger the ship the safety of navigation. Crankshaft deflection reflects the state of the shaft alignment. The inaccuracy in crankshaft alignment causes the crankshaft uneven wear and leads to a fatigue crack damage, or even crankshaft fracture. The marine engineers know about the working condition of the crankshaft by measuring crankshaft deflection, so as to ensure safe and reliable operation of diesel engines as well as avoid or reduce shaft accidents.Crankshaft of marine diesel engine was taken as research object in this article. Introduce the mechanism of crankshaft deflection development, the significance of measuring it, and measuring tools and methods. Study all kinds of influence factor of the crankshaft deflection difference various in the diesel engine crankshaft in the process of installation and operation. And put forward the relevant countermeasures in the maintenance of diesel engine crankshaft deflection in the range of a reasonable extent.On the basis of the analysis of the measuring tools and methods of marine diesel engine crankshaft deflection,study the feasibility on the use of microcontroller as a core processor to take crankshaft deflection, that digital display all the figures. This instrument needn't enter into crankcase except for mount and remove it. It makes measurement of simple, convenient and secure, reduced the human error, the measurement accuracy greatly improved. Overcome the shortcomings that engineer need enter into the crankcase to read the data when take the crankshaft deflection in the traditional measurement methods.On the aspect of designing the measuring instrument hardware, the differential transformer displacement sensor, the AD698, measurement amplifier and microcontroller were respectively selected as the sensor part of the measurement instrument, differential transformer sensor signal conditioning circuit, signal amplification circuit and the core data-processing circuit. Additionally, a low-pass filter circuit and Analog-Digital conversion circuit were introduced into the main circuit. PROTEL software platform was used to draw a circuit schematic diagram and print circuit board diagram. In the design of the software, the C51 language was developed to compile programs for all modules, the main program can reasonably call the subroutine, and store figure images, display, communicate, print, etc. Finally, the programmer was used to debug and modify the software and hardware and proves to be fast, accurate, and reliable.