Fault Diagnosis of Internal Combustion Engine Valve Clearance Using the Impact Commencement Detection Method.

Zhinong Jiang,Jinjie Zhang,Zijia Wang,Zhiwei Mao

doi:10.3390/s17122916

Zhinong Jiang, Jinjie Zhang + Show 2 more

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https://doi.org/10.3390/s17122916

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Abstract

Internal combustion engines (ICEs) are widely used in many important fields. The valve train clearance of an ICE usually exceeds the normal value due to wear or faulty adjustment. This work aims at diagnosing the valve clearance fault based on the vibration signals measured on the engine cylinder heads. The non-stationarity of the ICE operating condition makes it difficult to obtain the nominal baseline, which is always an awkward problem for fault diagnosis. This paper overcomes the problem by inspecting the timing of valve closing impacts, of which the referenced baseline can be obtained by referencing design parameters rather than extraction during healthy conditions. To accurately detect the timing of valve closing impact from vibration signals, we carry out a new method to detect and extract the commencement of the impacts. The results of experiments conducted on a twelve-cylinder ICE test rig show that the approach is capable of extracting the commencement of valve closing impact accurately and using only one feature can give a superior monitoring of valve clearance. With the help of this technique, the valve clearance fault becomes detectable even without the comparison to the baseline, and the changing trend of the clearance could be trackable.

Highlights

Internal combustion engines (ICEs), as a power source, are widely used in the automobile industry, ship and power equipment
We study the detection approach of the ICE valve clearance fault using vibration analysis
The valve clearance refers to the distance between the valve cap and rocker as illustrated in where θ is the crank angle, lCAM (θ ) is the lifting of cam, λ RA is the arm length ratio of the rocker, cVT

Summary

Introduction

Internal combustion engines (ICEs), as a power source, are widely used in the automobile industry, ship and power equipment. The techniques for ICE fault detection mainly include vibration [4], acoustic emission [5], in-cylinder pressure [6] and the crank angular velocity [7]. The valve clearance refers to the distance between the valve cap and rocker as illustrated in lVAL (θ ) = lCAM (θ )·λ RA − cVT − Fpre KVT (1). Where θ is the crank angle, lCAM (θ ) is the lifting of cam, λ RA is the arm length ratio of the rocker, cVT represents the valve clearance, Fpre is the pretension force of valve springs, and KVT represents the stiffness of the valve train. For a given ICE, the structural parameters, including the cam profile, λ RA , Fpre , and KVT , have been determined.

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