第34卷，第6期 2014年6月
光谱学与光谱
告分
析
Spectroscopy and Spectral Analysis
ApplicationofMicrowaveDigestion/AASin
DetectingCrankshaftBearingKnock
CHENLi-dan',ZHAO Yan-ru?
1. Zhejiang Technology Institute of Economy, Hangzhou 310018, China
Vol.34,No, 6,pp1683-1687
June,2014
2. College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310028, China
The present study was carried out to detect crankshaft bearing knock using atomic absorption spec-
Abstract
trometry (AAS) in an innovative way. Lubricating oil of MAGOTAN 2. 0 with mileage of 1000 ~ 28000Km and sampling interval of 1oooKm changed into atomic vapor in the heat after digesting with microwave. Hollow cathode lamp made of the same element with metal content under test would radiate characteristic radiation with certain wavelength. A part of atomic vapor was launched with ground state atom after heating with graphite furnace. Concentration-absorbance working curve was finished with standard series sample after ab sorbance was measured. Finally, element content under test in oil was obtained based on the work curve. Da tabase of primary element (Cu and Pb) content of lubricating oil in the same engine with different mileage was established. Results showed that Cu, Pb content fluctuates with different mileage in a certain range. In practi cal engineering applications, primary metal content in lubricating oil of engine crankshaft bearing was measured and compared with content variation trend chart. This new method not only helps automobile maintenance per-sonnel to diagnose crankshaft bearing knock under no-disintegration situation but also is benefit for reducing
the maintenance cost of automobile greatly and improving diagnostic accuracy of crankshaft bearing knock Keywords
Microwave digestion; Atomic absorption spectrometry; Crankshaft bearing knock; Fault detection
中图分类号：0657.3
Introduction
文献标识码：A
D0I: 10. 3964/j. issn. 10000593( 2014)06168305
and reliability. In order to ensure the stability of engine, it is necessary to make early prediction of crankshaft bearing crack and maintain the engine depending on the engine circum
Clearance oversize between crankshaft journal and crank-shaft bearing of engine could cause impact load increased, thereby resulted in vibration strengthens and power coast-downs. Especially during the acceleration, the engine even would make continuous and rhythmic metal rapping sound like*boom, boom, boom". The heavy and nausea sound increased with the increase in engine load. Meanwhile, the oil pressure decreased obviously, the engine body produces large vibration when the phenomenon was serious. The crankshaft bearing knock easily causes severe damage like bearing burning and cracking, which affect the dynamic performance, economy
Received: 2013-09-17; aecepted: 2013-12-15
stances timely.
Engine crack mainly includes knock of piston knocking, piston pins, crankshaft bearing- and air valve, There are two major methods to detect engine crankshaft bearing knock, one method is artificial auscultation diagnostic and the other is in struments diagnostic. Artificial auscultation diagnostic named knock of engine was recurred by changing working condition of engine in order to detect kind of abnormal sound based on the characteristics and discipline of the knock. Automobile maintenance personnel would distinguish different abnormal sound based on relationship between different abnormal sound
Foundation item: The National Natural Science Foundation of China (50975258) , Public Welfare Project of Technology Department of Zhejiang
Province of China(2013C37078)
Biography: CHEN Li-dan, (1968—), teacher of Zhejiang Technology Institute of Economy
e-mail:CLD1121@126.com