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A Multi-Cylinder Airflow & Residual Gas Estimation Tool Applied to a Vehicle Demonstrator
Technical Paper
2010-01-0169
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
In a gasoline engine, the cycle-by-cycle fresh trapped charge, and corresponding unswept residual gas fraction (RGF) are critical parameters of interest for maintaining the desired air-fuel ratio (AFR). Accurate fueling is a key precursor to improved engine fuel economy, and reduced engine out emissions. Asymmetric flow paths to cylinders in certain engines can cause differences in the gas exchange process, which in turn cause imbalances in trapped fresh charge and RGF. Variable cam timing (VCT) can make the gas exchange process even more complex. Due to the reasons stated above, simplified models can result in significant estimation errors for fresh trapped charge and RGF if they are not gas dynamics-based or detailed enough to handle features such as variable valve timing, duration, or lift. In this paper, a new air flow and RGF measurement tool is introduced. The tool is a combination of 1-D gas dynamics modeling and imposed, measured dynamic pressure signals in the intake and exhaust manifolds. With this method, the components to be modeled in the gas exchange system are reduced to a minimum, making it possible to model the gas exchange process with adequate detail and still maintain reasonable tool execution time. In this approach, the accuracy of the air flow and RGF estimation are not influenced by the location of pressure transducers and it is possible to “track” EGR flow from the exhaust to the intake system. The tool is demonstrated on a 4-cylinder gasoline engine powered vehicle with dual intake and exhaust cam phasing. Predictions from the tool are compared to AFR and other real-time signals measured during a variety of different real-world transient drive cycles. The instantaneous fresh trapped charge, RGF across all cylinders, as well as the influence of VCT actuation is discussed.
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Citation
Subramaniam, M., Kleeberg, H., Bhattacharyya, A., Chomic, N. et al., "A Multi-Cylinder Airflow & Residual Gas Estimation Tool Applied to a Vehicle Demonstrator," SAE Technical Paper 2010-01-0169, 2010, https://doi.org/10.4271/2010-01-0169.Also In
References
- Liu, J. Kleeberg, H. Tomazic, D. Ciaravino J. Amer, A. “A Model for On-Line Monitoring of In-Cylinder Residual Gas Fraction (RGF) and Mass Flowrate in Gasoline Engines,” SAE Technical Paper 2006-01-0656 2006
- Liu, J. Schorn, N. Schernus C. Peng, L. “Comparison of Method of Characteristics with Finite Difference Methods on One-Dimensional Gas Flow in IC Engine Manifold,” SAE Technical Paper 960078 1996
- Ford R. Collings, N. “Measurement of Residual Gas Fraction using a Fast Response NO Sensor,” SAE Technical Paper 1999-01-0208 1999
- Alger T. Wooldridge, S. “Measurement and Analysis of the Residual Gas Fraction in an SI Engine with Variable Cam Timing,” SAE Technical Paper 2004-01-1356 2004
- Jang, J. Yeom K. Bae, C. “Effects of Exhaust Throttling on Engine Performance and Residual Gas in an SI engine,” SAE Technical Paper 2004-01-2974 2004
- Shayler, P. Winborn, L. Hill M. Eade, D. “The Influence of Gas/Fuel Ratio on Combustion Stability and Misfire Limits of Spark- Ignition Engines,” SAE Technical Paper 2000-01-1208 2000
- Giansetti, P. Chamaillard, Y. Charlet, A. Higelin P. Couet, S. “A Model for Residual Gas Fraction Prediction in Spark Ignition Engines,” SAE Technical Paper 2002-01-1735 2002
- Cavina, N. Siviero, C. Suglia, R. “Residual Gas Fraction Estimation: Application to a GDI Engine With Variable Valve Timing and EGR,” SAE Technical Paper 2004-01-2943 2004
- Schwarz F. Spicher, U. “Determination of Residual Gas Fraction in IC Engines,” SAE Technical Paper 2003-01-3148 2003
- Koehler, U. Bargende, M. “A Model for a Fast Prediction of the In-Cylinder Residual Gas Mass,” SAE Technical Paper 2004-01-3053 2004