Study On Wireless Intelligent Crankshaft Deflection Gauge

Crankshaft deflection which could reflect the state of diesel engine crankshaft is animportant parameter, which could understand and grasp the deformation of the crankshaft andwear of main bearing. The ship is required to measure the crankshaft deflection regularly duringthe operational process, using the result to decide whether to continue to run or to be repaired tothe diesel engine, so that to ensure the safe operation of the ship. In view of the currentconditions that mechanical gauge and the wired digital display crankshaft deflection gauge ofdiesel engine measure the crankshaft deflection, a wireless intelligent crankshaft deflectiongauge of the diesel engine was designed. Existing crankshaft deflection gauge of the dieselengine could be replaced by this measuring instrument, it was more convenient for the engineersto measure the crankshaft deflection.Based on the functions of the wireless intelligent crankshaft deflection gauge, systemoverall design scheme was given in this paper. Designed a hall displacement sensor by a hallelement of AH3503and one pair of magnets which had a diameter of6mm; The wireless moduleof nRF24L01which was low-power and low-cost was used to transfer the signal of crankshaftdeflection; In order to achieve to measure5points of crankshaft deflection values of a cylinderin one measurement, the crank angle detection module was designed by single polarity hallswitch of CS3144.This paper introduced the hardware of crankshaft deflection gauge, including signalconditioning, AD data acquiring, signal wireless transmission, human-computer interactioninterface, the USB interface and the power supply, and the circuit schematic of every modulewas designed, integrating all modules to form the measuring instrument hardware system. ThePCB of crankshaft deflection gauge was given.This paper introduced the software of each module, including crankshaft deflectionacquisition subprogram, human-computer interaction interface subprogram, AD data collectingsubprogram, signal wireless transmission subprogram and software filtering subprogram, etc.Then a complete software program was formed for supportting the hardware to measure thecrankshaft deflection.Finally, the sensor calibration was carried out. The linear fitting of data was carried out bythe least squares method in software of Oringin8.0, and the fitting formula of voltage anddisplacement of the transducer was calculated. The fitting formula was imported into measuringinstrument of the controller to realize the crankshaft deflection measurement. The field test was conducted in the college of automation engine laboratory, and collected experimental data. Inthis paper, the accurate and reliability of the instrument measurement were verified bycomparing the collected data of the designed crankshaft deflection gauge and the actualdisplacement data of micrometer caliper.