A Misfire Detection Index for Four-Stroke Single-Cylinder Motorcycle Engines—Part II: Gap Distance and Gap Slope
Journal Article
03-14-01-0002
ISSN: 1946-3936, e-ISSN: 1946-3944
Sector:
Citation:
Han, P. and Lee, J., "A Misfire Detection Index for Four-Stroke Single-Cylinder Motorcycle Engines—Part II: Gap Distance and Gap Slope," SAE Int. J. Engines 14(1):15-27, 2021, https://doi.org/10.4271/03-14-01-0002.
Language:
English
Abstract:
Two new misfire detection indexes for single-cylinder motorcycle engines—dubbed
gap distance (GD) and gap slope (GS)—are proposed in this study. GD and GS
quantify the change in engine angular acceleration using the tooth time measured
by the crankshaft position sensor (CKPS). GD is defined as the product of the
spacing distance I (the distance from the top dead center at the explosion
stroke [TDC2] to the engine speed trend line parallel to the engine speed axis)
and spacing distance II (the distance from the bottom dead center at the
expansion stroke [BDC2] to the engine speed trend line parallel to the engine
speed axis). GS is defined as the difference between the two slopes between the
engine speed inclination line and the engine speed trend line. Here the engine
speed trend line connects two engine speeds at the top dead center at the intake
stroke (TDC1) of the current and subsequent cycles. The GD and GS indexes can
detect misfires using the engine speeds at only four teeth. The location of
these four teeth could be changed to best simulate the change in engine angular
acceleration for engines. The threshold range for GD and GS lies between the
point where the misfire detection rate reaches 100% and the point where both the
ratio of misfire detection to misfire signal (Mdtn/Msig) and the ratio of
misfire signal to misfire detection (Msig/Mdtn) begin to deviate from 100%. Both
GD and GS show a good misfire detection rate of approximately 99% and a perfect
detection fault rate of 0% for an engine speed range of 3,000-8,000 under 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%.