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Measurement Errors in Real-Time IMEP and ROHR Evaluation
Technical Paper
2008-01-0980
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Combustion control is one of the key factors to obtain better performance and lower pollutants emissions, for diesel, spark ignition and HCCI engines. This paper describes a real-time indicating system based on commercially available hardware and software, which allows the real-time evaluation of Indicated Mean Effective Pressure (IMEP) and Rate of Heat Release (ROHR) related parameters, such as 50%MFB, cylinder by cylinder, cycle by cycle. This kind of information is crucial for engine mapping and can be very important also for rapid control prototyping purposes.
The project objective is to create a system able to process in-cylinder pressure signals in the angular domain without the need for crankshaft encoder, for example using as angular reference the signal coming from a standard equipment sensor wheel. This feature can be useful both for test bench and on-board tests. In order to gain reliable results or acceptable precision on ROHR-related parameters (ROHR peak & 50%MFB, for example) a high sampling rate is required for the in-cylinder pressure. Since the angular reference signal can have low angular resolution (6 degrees with a typical sensor wheel), the in-cylinder pressure signal sampling rate must be higher than the crankshaft signal frequency. The choice for this application has been to use a high sample rate on a time base for the cylinder pressure signal, performing the transformation from the time domain to the angular domain (necessary in order to evaluate the indicating parameters) by means of an interpolation algorithm.
The use of standard automotive crankshaft position referencing sensors (and sensor wheels), however, increases the risk of angular errors in the conversion from the time to the angular domain: transducers intrinsic delay, analog filters delay, TDC referencing error could cause large errors on RHOR and IMEP. Furthermore, if the in-cylinder pressure signal mean value is reconstructed by means of the Polytropic Index Pressure Referencing methodology, errors on the pressure samples angular position would lead to a wrong estimation of the pressure signal mean value. This would introduce an offset in the pressure trace, affecting ROHR results.
The paper shows how these considerations can be taken into account in the implementation of the algorithm of IMEP and RHOR evaluation. In order to correct IMEP and ROHR calculations, some parameters need to be identified: the position sensor delay, the TDC actual position and the sensor wheel teeth unevenness. Algorithms implementing these functions have been integrated within the main application. Once the correction-parameters are estimated, they are directly used for IMEP and RHOR evaluation.
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Corti, E., Moro, D., and Solieri, L., "Measurement Errors in Real-Time IMEP and ROHR Evaluation," SAE Technical Paper 2008-01-0980, 2008, https://doi.org/10.4271/2008-01-0980.Also In
References
- Hata Y. Ikuera K. Morita T. Abo T. Engine Control System using a Cylinder Pressure Sensor SAE Technical Paper, IEEE Proceedings 136 2 March 1989
- Gassenfeit E.H. Powell J. D. Algorithms for Air-Fuel Ratio Estimation Using Internal Combustion Engine Cylinder Pressure SAE Technical Paper 8903001
- Watanabe S. Machida K. Iijima K. Tomisawa N. A sophisticated Engine Control System Using Combustion Pressure Detection SAE Technical Paper 960042
- Tunestal P. Wilcutts M. In-Cylinder Measurements for Engine Cold-Start Control International Conference on Control Applications August 22-27 1999
- Muller R. Hart M. Truscott A. Noble A. Krotz G. Eickhoff M. Cavalloni C. Gnielka M. Combustion Pressure Based Engine Management System SAE Technical Paper 2000-01-0928
- Sellnau M. C. Matekunas A. F. Cylinder Pressure Based Engine Control Using Pressure-Ratio-Management and Low-Cost Non-Intrusive Cylinder Pressure Sensors SAE Technical Paper 2000-01-0932
- Muller N. Isermann R. Control of Mixture Using Cylinder Pressure Sensors SAE Technical Paper 2001-01-3382
- Tunestal P. Wilcutts M. Lee A. T. Hedrick J. K. A Method of Lean Air-Fuel Ratio Control Using Combustion Pressure Measurements JSAE Review 389 393 2001
- Schiefer D. Maennel R. Advantages of Diesel Engine Control Using In-Cylinder Pressure Information for Closed Loop Control SAE Technical Paper 2003-01-0364
- Helmantel A. Denbratt I. HCCI Operation of a Passenger Car Common-Rail Di Diesel Engine With Early Injection of Conventional Diesel Fuel SAE Technical Paper 2004-01-0935
- Kumar R. Zheng M. Asad U. Reader G. T. Heat Release Based Adaptive Control to Improve Low Temperature Diesel Engine Combustion SAE Technical Paper 2007-01-0771
- Yoon M. Lee K. Sunwoo M. Oh B. Cylinder Pressure Based Combustion Phasing Control of a CRDI Diesel Engine SAE Technical Paper 2007-01-0772
- Husted H. Kruger D. Fattic G. Ripley G. Kelly E. Cylinder Pressure Based Control of Pre-Mixed Diesel Combustion SAE Technical Paper 2007-01-0773
- Schten K. Ripley G. Punater A. Erikson C. Design of an Automotive Grade Controller for In-Cylinder Pressure Based Engine Control Development SAE Technical Paper 2007-01-0774
- Ponti F. In-Cylinder Pressure Measurements: requirements for On-Board Engine Control ASME Proceedings, ICES 2003-666
- Corti E. Moro D. Solieri L. Real-Time Evaluation of IMEP and ROHR-Related Parameters SAE Technical Paper 2007-24-0068
- Corti E. Solieri L. Rapid Control Prototyping System for Combustion Control SAE Technical Paper 2005-01-3754
- Corti E. Moro D. Minelli G. Solieri L. Advantages of using FPGA components for innovative control systems implementation on automotive engines Modena-Motori, High Tech Engines and Cars, 11 th International Conference 2005
- Kearney M. J. Knock Signal Conditioning Using the Discrete Fourier Transform and Variable Detection Window Length SAE Technical Paper 2007-01-1509
- Randolph A. L. Methods of Processing Cylinder Pressure Transducer Signals to Maximize Data Accuracy SAE Technical Paper 900170 1990
- Brunt M. F. J. Pond C. R. Evaluation of Techniques for Absolute Cylinder Pressure Correction SAE Technical Paper 1997, 970036
- Fleming W. J. Overview of Automotive Sensors, IEEE sensors Journal 1 4 December 2001
- Ponti F. Development of a Torsional Behavior Powertrain Model for Multiple Misfire Detection ASME Proceedings, ICES2005-1035
- Ponti F. Indicated Torque Estimation Using a Torsional Behavior Model of the Engine SAE Technical Paper, 2005-01-3761
- Tazerout m. LeCorre O. Rousseau S. Tdc Determination in IC Engines Based on the Thermodynamic Analysis of the Temperature-Entropy Diagram SAE Technical Paper 1999-01-1489
- Nilsson Y. Eriksson L. Determining Tdc Position Using Symmetry and Other Methods SAE Technical Paper 2004-01-1458
- Pipitone E. Beccari A. Beccari S. The Experimental Validation of a New Thermodynamic Method for TDC Determination SAE Technical Paper 2007-24-0052