ANALYSIS OF VIBRATION ON AN ENGINE BLOCK CAUSED BY COMBUSTION IN A DIESEL ENGINE |
Yoonwoo Lee1, Seunghyun Lee1, Hoimyung Choi2, Kyoungdoug Min1 |
1Seoul National University 2Gachon University |
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ABSTRACT |
An accelerometer replaced an in-cylinder pressure sensor to detect the combustion status. The correlation
between the vibration on an engine block caused by direct combustion as well as the combustion status was analyzed. The
direct combustion vibration was determined. The direct combustion vibration on an engine block was blended with indirect
combustion vibrations and other accessories. In addition, the combustion status was specified among several combustion
status parameters, namely, RoHR, MPRR, and the peak pressure. There were two distinct vibrations in the motoring state. The
frequency range of 2.5−8 kHz and 0−10oCA aTDC was assumed to be a crankshaft vibration. The other vibration, 1−3 kHz
and 20−30oCA aTDC, was estimated as a slap motion of the piston. The combustion vibration frequency was 0.1−8 kHz after
combustion. As an injector vibration (3−8 kHz) disrupted the search for combustion noise, a 0.1−2 kHz vibration range was
appropriate for finding the correlation with the direct combustion state and the peak of the RoHR. As the peak of the RoHR
was proportional to the combustion noise, the estimated peak of the RoHR can be used to control the diesel engine’s
combustion noise. Estimation was possible in the transient and steady states. |
Key Words:
Compressed ignition combustion control, Combustion noise, Combustion vibration, Rate of heat release rate,
Max pressure rise rate |
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