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Time-Resolved Diagnostic of Electrode Erosion in Spark Plugs

Bi, Ruike LU (2019) FYSM60 20191
Department of Physics
Combustion Physics
Abstract
The short lifetime of spark plugs in heavy-duty truck and stationary engines has been a major concern in the relevant industry. In this thesis work a time-resolved approach to detect the evaporation erosion of Ni electrodes in electrical discharges was proposed, and multiple detection methods were used to study the spark discharge. Spectroscopic study of the discharge's emission illustrated the existence of the Ni atomic lines in the spectral range of 338 nm to 355 nm. Spectra also reported randomness in both the appearance of the Ni signal and the position where the signal is recorded. Based on the spectral measurement, it was proposed that a photomultiplier tube and a 10-nm-bandwidth band-pass filter centered at 343 nm can be used to... (More)
The short lifetime of spark plugs in heavy-duty truck and stationary engines has been a major concern in the relevant industry. In this thesis work a time-resolved approach to detect the evaporation erosion of Ni electrodes in electrical discharges was proposed, and multiple detection methods were used to study the spark discharge. Spectroscopic study of the discharge's emission illustrated the existence of the Ni atomic lines in the spectral range of 338 nm to 355 nm. Spectra also reported randomness in both the appearance of the Ni signal and the position where the signal is recorded. Based on the spectral measurement, it was proposed that a photomultiplier tube and a 10-nm-bandwidth band-pass filter centered at 343 nm can be used to investigate the temporal behavior of the Ni emission during one discharge, which can in principle reflect the erosion rate of the Ni electrode. The results reported a rapid rise in Ni emission at the beginning of the discharge. In the photomultiplier tube signal profiles, a stochastic behavior was also observed, in both the temporal width and the timing of the emission peaks. The effect of different parameters and spark modes on the erosion rate of Ni electrodes was studied statically. It was found that the erosion of the electrodes scales up almost linearly with the coil charging time; no clear correlation was observed between electrode erosion and cross flow speed or repetition rate of the discharge. In a capacitive system, it was found that the Ni electrode suffers more erosion when acting as the anode and that AC discharges do less erosion than DC ones. Finally, the morphology of new and worn electrodes was compared using a self-built macro imaging system. (Less)
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author
Bi, Ruike LU
supervisor
organization
course
FYSM60 20191
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8981220
date added to LUP
2019-06-12 09:19:19
date last changed
2019-06-12 09:19:19
@misc{8981220,
  abstract     = {The short lifetime of spark plugs in heavy-duty truck and stationary engines has been a major concern in the relevant industry. In this thesis work a time-resolved approach to detect the evaporation erosion of Ni electrodes in electrical discharges was proposed, and multiple detection methods were used to study the spark discharge. Spectroscopic study of the discharge's emission illustrated the existence of the Ni atomic lines in the spectral range of 338 nm to 355 nm. Spectra also reported randomness in both the appearance of the Ni signal and the position where the signal is recorded. Based on the spectral measurement, it was proposed that a photomultiplier tube and a 10-nm-bandwidth band-pass filter centered at 343 nm can be used to investigate the temporal behavior of the Ni emission during one discharge, which can in principle reflect the erosion rate of the Ni electrode. The results reported a rapid rise in Ni emission at the beginning of the discharge. In the photomultiplier tube signal profiles, a stochastic behavior was also observed, in both the temporal width and the timing of the emission peaks. The effect of different parameters and spark modes on the erosion rate of Ni electrodes was studied statically. It was found that the erosion of the electrodes scales up almost linearly with the coil charging time; no clear correlation was observed between electrode erosion and cross flow speed or repetition rate of the discharge. In a capacitive system, it was found that the Ni electrode suffers more erosion when acting as the anode and that AC discharges do less erosion than DC ones. Finally, the morphology of new and worn electrodes was compared using a self-built macro imaging system.},
  author       = {Bi, Ruike},
  language     = {eng},
  note         = {Student Paper},
  title        = {Time-Resolved Diagnostic of Electrode Erosion in Spark Plugs},
  year         = {2019},
}