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Accuracy Limits of IMEP Determination from Crankshaft Speed Mesurements
ISSN: 0148-7191, e-ISSN: 2688-3627
Published March 4, 2002 by SAE International in United States
Annotation ability available
The paper presents a method of determining the Indicated Mean Effective Pressure (IMEP) and the gas pressure torque of a multi-cylinder engine using data obtained from the measurement of the crankshaft's speed variation. At steady state operating conditions a Fourier series describe the gas pressure torque of a cylinder and the resultant torque may be obtained by adding the harmonic components corresponding to all cylinders. Only the major harmonic orders, having the same phase for all cylinders add algebraically appearing with large contributions in the spectrum of the resultant torque. The lowest major component has a low frequency and, at this frequency, the crankshaft behaves dynamically like a rigid body. In this situation it is possible to correlate the amplitude of this harmonic order of the gas pressure torque to the same harmonic order of the crankshaft speed. The statistical nature of the cycle-to-cycle variation in the engine operation determines limits of the accuracy by which the IMEP and the gas pressure torque may be calculated by this method. The errors are fairly low at high and medium engine loads but increase at low loads.
CitationTaraza, D., "Accuracy Limits of IMEP Determination from Crankshaft Speed Mesurements," SAE Technical Paper 2002-01-0331, 2002, https://doi.org/10.4271/2002-01-0331.
- Rizzoni G., Estimate of Indicated Torque from Crankshaft Speed Fluctuations: A Model for the Dynamics of the I.C. Engine, IEEE Transactions on Vehicular Technology, Vol. 38, No. 3, 1989
- Citron S.J., O'Higgins J.E., Chen L.Y. Cylinder by Cylinder Engine Pressure and Pressure Torque Waveform Determination Utilizing Speed Fluctuation. SAE Paper 890486.
- Champoussin J.C., Ginoux S. Engine Torque Determination by Crank Angle Measurements: State of the Art, Future Prospects. SAE Paper 970532.
- Connoly F., Rizzoni G., Real Time Estimation of Engine Torque for the detection of Engine Misfires, Transactions of ASME, Journal of Dynamic Systems Measurements and Control, Vol.116, No. 2, 1994.
- Guezenec Y.G., Gyan Ph., A novel Approach to Real- Time Estimation of the Individual Cylinder Combustion Pressure for S.I. Engine Control, SAE Paper 1999-01-0209.
- Gyan Ph., Ginoux St., Champoussin J.C., Guezennec Y., Crankangle Based Torque Estimation: Mechanistic/Stochastic, SAE Paper 2000-01-0559
- 10. Iida K., Akishino K., Kido K., IMEP Estimation from Instantaneous Crankshaft Torque Variation, SAE Paper 900617.
- Chen K.S., Chen S. Engine Diagnostics by Dynamic Shaft Measurement: A Progress Report. SAE Paper 932412.
- Taraza D. Possibilities to Reconstruct Indicator Diagrams by Analysis of the Angular Motion of the Crankshaft. SAE Paper 932414.
- Taraza D., Henein A.N., Bryzik W. Determination of the Gas-Pressure Torque of a Multicylinder Engine from Measurements of the Crankshaft's Speed Variation. SAE Paper 980164.
- Taraza D., Henein N.A., Bryzik W., The Frequency Analysis of the Crankshaft's Speed Variation: A Reliable Tool for Diesel Engine Diagnosis, ASME Transactions, Journal of Engineering for Gas Turbines and Power, Vol 123, No. 2, 2001.
- Hafner K.E., Maass H. Torsionsschwingungen in der Verbrennungskraftmaschine. Springer Verlag, Wien, New-York, 1985.
- Taraza D., Statistical correlation Between the Crankshaft's Speed Variation and the Contribution of Individual Cylinders to the Total Engine Output, ICE-Vol. 35, ICE Fall Technical Conference, ASME 2000.
- Taraza D., Quantifying Relationships Between the Crankshaft's Speed Variation and the Gas Pressure Torque, SAE Paper 2001-01-1007
- Taraza D., A Probabilistic Approach to Engine Balance, ASME Transactions, Journal of Engineering for Gas Turbines and Power, Vol 122, No. 4, 2000.