US 12,436,064 B2
Method and device for detecting misfiring cylinder of reciprocating internal-combustion engine using torsional vibration signal
Jeonggeun Park, Changwon-si (KR)
Assigned to EONC CO., LTD., Changwon-si (KR)
Appl. No. 18/269,764
Filed by EONC CO., LTD., Changwon-si (KR)
PCT Filed Dec. 28, 2021, PCT No. PCT/KR2021/020096
§ 371(c)(1), (2) Date Jun. 27, 2023,
PCT Pub. No. WO2022/146001, PCT Pub. Date Jul. 7, 2022.
Claims priority of application No. 10-2020-0184079 (KR), filed on Dec. 28, 2020.
Prior Publication US 2024/0068909 A1, Feb. 29, 2024
Int. Cl. G01M 15/05 (2006.01); F02D 41/00 (2006.01); F02D 41/14 (2006.01); F02D 41/22 (2006.01); F02D 41/28 (2006.01); G01M 15/11 (2006.01)
CPC G01M 15/05 (2013.01) [F02D 41/009 (2013.01); F02D 41/1498 (2013.01); F02D 41/22 (2013.01); G01M 15/11 (2013.01); F02D 2041/228 (2013.01); F02D 2041/286 (2013.01); F02D 2200/101 (2013.01); F02D 2200/1012 (2013.01); F02D 2200/1015 (2013.01); Y02T 10/40 (2013.01)] 2 Claims
OG exemplary drawing
 
1. A misfire detection apparatus for a reciprocating internal-combustion engine, comprising:
a torsional vibration sensor arranged at a shaft line of the engine for detecting rotational speed fluctuations, the torsional vibration sensor outputting a torsional vibration signal;
a camshaft position sensor, optionally included for a 4-stroke engine, arranged at a camshaft of the engine for detecting a reference signal indicative of a top dead center of a reference cylinder, the camshaft positon sensor outputting a camshaft position signal;
a signal processing unit configured to obtain amplitudes and phases of a fundamental frequency component and harmonic components by performing a Fast Fourier Transform (FFT) on the torsional vibration signal;
an application processing unit configured to detect a misfiring event and determine a misfiring cylinder position by;
detecting the misfiring event when the amplitude of the fundamental frequency component exceeds a preset threshold; and
identifying the misfiring cylinder position by calculating an explosion angle (FAi) of the misfiring cylinder according to the relation;
FAi=ixmax·dx−(1/k)(3π/2−β(k)),
wherein ixmax·dx is a crank-angle value obtained by multiplying ixmax, an index corresponding to a sample at which the amplitude of the fundamental frequency component of the torsional vibration signal reaches a maximum while a fundamental frequency component of the excitation force attains a minimum having a phase angle β(k), by dx, a fixed crank-angle increment between successive torsional vibration signal samples;
wherein ρ(k) is calculated from torque harmonic coefficients and an explosion order supplied by an engine manufacturer;
wherein, k is 1.0 for a 2-stroke engine and 0.5 for a 4-stroke engine; and
wherein, for the 4-stroke engine, a crank-angle reference is synchronized to the top dead center of a reference cylinder using the camshaft position signal;
a transmission unit connected the application processing unit and configured to transmit the result of the detected misfiring cylinder; and
a display device configured to receive and display the detected misfiring cylinder.