Misfire Detection Index for Four-Stroke Single-Cylinder Motorcycle Engines—Part I: Detrended Engine rpm Amplitude
Journal Article
03-14-01-0001
ISSN: 1946-3936, e-ISSN: 1946-3944
Sector:
Topic:
Citation:
Han, P. and An, J., "Misfire Detection Index for Four-Stroke Single-Cylinder Motorcycle Engines—Part I: Detrended Engine rpm Amplitude," SAE Int. J. Engines 14(1):3-14, 2021, https://doi.org/10.4271/03-14-01-0001.
Language:
English
Abstract:
This article presents a misfire detection index for motorcycles with a
single-cylinder engine. Compared with automobiles with multicylinder engines,
attempts to diagnose single-cylinder motorcycle engine misfires have been rare.
Therefore, a new index, detrended engine rpm amplitude (DERA), is proposed to
detect misfires using tooth time measured by the crankshaft position sensor;
thus, there is no additional cost for the DERA index. This index is defined as
the difference between the squares of the maximum and minimum values of engine
speed (rpm) detrended by the engine speed trend line, instead of the linear
regression method. Thus calculating the DERA index becomes simple and fast, and
it is advantageous to reduce the computation time. Here the engine speed trend
line is a line connecting the engine speeds at the first teeth of the current
and subsequent cycles. The analysis of the optimal threshold for detecting
misfires reveals that DERA yields a good misfire detection rate of more than 98%
for an engine speed range of 3,000-8,000 rpm in load conditions of over 50%. If
the lower boundary limit for the load over which misfires can be accurately
detected is clearly defined, a good detection rate can be achieved even under
load conditions below 50%. If only two teeth among the entire teeth can be
specified optimally that best demonstrate the changes of the detrended engine
speed (DRPM) due to misfire, the DERA index could be used to diagnose misfires
even for motorcycles with a small number of teeth on the target wheel.