EFFECTS OF FILTERING THE ANGULAR MOTION OF THE CRANKSHAFT ON THE ESTIMATION OF THE INSTANTANEOUS ENGINE FRICTION TORQUE

✍ Scribed by H.K. NEHME; N.G. CHALHOUB; N.A. HENEIN

• Book ID: 102606393
• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 246 KB
• Volume: 236
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.2000.3038

✦ Synopsis

The focus of this study is to investigate the e!ects of "ltering the actual angular displacement, velocity and acceleration of the crankshaft on the computation of the instantaneous engine friction torque. These e!ects are isolated from those of measurement errors and/or noise by relying on a detailed model of the crank-slider mechanism to generate the rigid and #exible motions of the piston/connecting-rod/crankshaft mechanism along with the engine friction torque. The (P! ) method is used herein to estimate the instantaneous engine friction torque based on the actual and the "ltered angular displacement, velocity and acceleration of the crankshaft. The digital simulation results have demonstrated that the (P! ) method cannot produce an acceptable estimation of the instantaneous engine friction torque in spite of "ltering the actual angular motion of the crankshaft. It should be mentioned that the low-pass "lter is commonly implemented to attenuate the measurement noise and the e!ects of structural deformations on the measured angular velocity of the crankshaft. However, the ine!ectiveness of the low-pass "lter stems from the non-linearities of the crank-slider mechanism that induced superharmonic and combination resonance frequencies in the angular displacement, velocity and acceleration of the crankshaft. The "lter has severely attenuated some of the superharmonic resonance frequencies, which constitute an important part of the rigid-body behavior of the crankshaft that is needed by the (P! ) method to accurately predict the engine friction torque. Moreover, the "ltered signals would still be contaminated by the combination resonance frequencies that may appear in the low-frequency range commonly assumed to be dominated by the frequency components of the rigid-body motion of the crankshaft.