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Engine Idle Stability Analysis and Control
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English
Abstract
Periodic engine speed fluctuations of an Electronic Fuel Injection (EFI) engine system at idle conditions are analyzed by examining the two engine dynamics, filling dynamics and rotational dynamics of the engine. Utilizing simple models of engine dynamics linearized around the nominal operating point, it was predicted that the periodic engine speed fluctuations were caused by the instability of the derived vibration system.
These predictions are verified by the engine test, utilizing the frequency response method. The low frequency vibration at idle is confirmed to correspond to the idle hunting phenomenon, and its characteristics such as the resonant frequency and the stability depend on the control system as well as the engine mechanical structure.
Among the practical EFI system, the L-J (Mass-Flow) system is shown to be more stable than the D-J (Speed-Density) system.
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Citation
Nishimura, Y. and Ishii, K., "Engine Idle Stability Analysis and Control," SAE Technical Paper 860415, 1986, https://doi.org/10.4271/860415.Also In
References
- Morris R. L. Warlick M. V. Borcherts R. H. “Engine Idle Dynamics and Control: A 5,8 L Application” SAE Paper 820778 1982
- Coats, F. E. Jr. Fruechte R. D. “Dynamic Engine Models for Control Development Part II: Application to Idle Speed Control” Int'l J. of Veh. Des.. Special Issue: Application of Control Theory in the Auto Industry 1982
- Takahashi T. Ueno T. Yamamoto A. Sanbuichi H. “A Simple Engine Model for Idle Speed Control” SAE Paper 850291 1985
- Mihelc W. P. Citron S. J. “An Adaptive Idle Mode Control System” SAE Paper 840443 1984
- Morris R. L. Hapkins M. G. Borcherts R. H. “An Identification Approach to Throttle-Torque Modeling” SAE Paper 810448 1981
- Dobner D. J. “Dynamic Engine Models for Control Development Part I; Nonlinear and Linear Model Formulation” Int'l J. of Veh. Des., Special Issue: Application of Control Theory in the Auto Industry 1982