This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Development of a Detailed Friction Model to Predict Mechanical Losses at Elevated Maximum Combustion Pressures
ISSN: 0148-7191, e-ISSN: 2688-3627
Published March 05, 2001 by SAE International in United States
Annotation ability available
Event: SAE 2001 World Congress
Engineers use phenomenological simulation models to determine engine performance. Using these models, we can predict with reasonable accuracy the heat release rate mechanism inside the engine cylinder, which enables us to obtain a prediction of the pressure history inside the engine cylinder. Using this value and the volume change rate of the combustion chamber, we can then estimate the indicated power output of the engine. However, in order to obtain the brake engine power output we must have an indication for the mechanical losses, a great part of which are friction losses. Up to now various correlations have been proposed that provide the frictional mean effective pressure as a function mainly of engine speed and load. These correlations have been obtained from the processing of experimental data, i.e. experimental values for the indicated and brake power output of engines. Using these correlations we can get an acceptable prediction of the friction mean effective pressure and thus, estimate the engine brake power output from the corresponding indicated value. The process is especially important when analyzing the performance of engines on the field where the brake power output cannot be measured directly or when developing new engines. A serious problem associated with the use of these correlations is that in the relevant expressions exist coefficients that are usually unknown. For this reason, these models have to be calibrated using known values, which is a disadvantage. Another problem is that these models predict in a very rough manner the effect of the maximum combustion pressure which nowadays has been increased considerably in production DI diesel engines; in some cases values around 170 -180 bar have been reported. To overcome the previous problems and mainly to examine the effect of maximum combustion pressure on frictional losses, in the current work a detailed model for the estimation of all frictional forces from the moving elements of the engine is developed. Using the developed model, it is made possible to predict the history of the various forces during an engine operating cycle and mainly friction mean effective pressure and mechanical efficiency. The model has been applied on a modern diesel engine with high maximum combustion pressures at three different engine-operating speeds and two different loads. As revealed, the model predicts with good accuracy the frictional losses at all engine operating conditions examined and the effect of the maximum combustion pressure. The contribution of the last one is revealed not to be very significant at high values, despite initial expectations.
- D. A. Kouremenos - Mech. Eng. Dept., National Technical University of Athens
- C. D. Rakopoulos - Mech. Eng. Dept., National Technical University of Athens
- D. T. Hountalas - Mech. Eng. Dept., National Technical University of Athens
- T. K. Zannis - Mech. Eng. Dept., National Technical University of Athens
CitationKouremenos, D., Rakopoulos, C., Hountalas, D., and Zannis, T., "Development of a Detailed Friction Model to Predict Mechanical Losses at Elevated Maximum Combustion Pressures," SAE Technical Paper 2001-01-0333, 2001, https://doi.org/10.4271/2001-01-0333.
- Heywood J.B, “Internal Combustion Engine Fundamentals”, McGraw - Hill, New York, 1988.
- Gish R.E, McGullough J.D, Retzloff J.B and Mueller H.T, “Determination of engine friction”, SAE Transactions, Vol.66, pp. 649 - 661, 1958.
- Ricardo H.R. and Hempson J.G.G,“The High - Speed Internal Combustion Engine”, Blackie & Son, London, 1960.
- Bishop I.N., “Effect of design variables on friction and economy,” SAE Transactions, Vol.73, pp.334-358, 1965.
- Chen S.F. and Flynn P, “Development of a compression ignition research engine”, SAE paper No 650733, 1965.
- Millington B.W. and Hartles E.R, “Friction losses in diesel engines,” SAE paper No 680590, 1968.
- Ferguson C.R., “Internal Combustion Engines (Applied Thermosciences),” John Wiley & Sons, New York, 1986.
- Taylor C.F, “The Internal Combustion Engine in Theory and Practice Vol I,” MIT Press, Cambridge, M.A., 1985.
- Rezeka S.F. and Henein N.A, “A new approach to evaluate instantaneous friction and its components in internal combustion engines,” SAE paper No 840179, 1984.
- Gardner T.P. and Henein N.A, “Diesel starting: A mathematical model”, SAE Transactions, Vol. 97, Section 3, pp. 6728 - 6740, 1988.
- Tuccilo R., Arnone L., Bozza F., Nocera R. and Senatore A., “Experimental correlations for heat release and mechanical losses in turbocharged diesel engines, SAE Transactions, Vol. 102, Section 3, pp. 2073 - 2086, 1993.
- Marzouk M. and Watson N, “Load acceptance of turbocharged diesel engines”, Inst.Mech.Engrs. Conference on Turbocharging and Turbochargers, Paper C54/78, pp 45 - 57, 1978.
- Winterbone D.E. and Tennant D.W.H.,“The variation of friction and combustion rates during diesel engine transients,” SAE paper No 810339, 1981.
- Kovach J.T., Tsakiris E.A. and Wong L.T., “Engine friction reduction for improved fuel economy,” SAE paper No 820085, 1982.
- Giulli E., “A review of internal combustion engine losses”, Proc.Inst.Mech.Engrs., Vol.207, pp.229 - 240, 1993.
- Shiao Y.J and Moskwa J. J, “An investigation of load force and dynamic error magnitude using the lumped mass connecting rod model”, SAE paper No 930617, 1993.
- Hountalas D.T. and Kouremenos A.D., “Development and application of a fully automatic troubleshooting method for large marine diesel engines”, Appl.Therm.Engng, Vol.19, pp.299-324, 1999.
- Kouremenos D.A., Rakopoulos C.D. and Hountalas D.Ô, “Multi-zone combustion modeling for the prediction of pollutant emissions and performance of DI diesel engines”, SAE Transactions, J.of Engines, Vol.106, Section 3, pp.940-957, 1997.
- Kouremenos D.A., Rakopoulos C.D. and Hountalas D.T., “Thermodynamic analysis of indirect injection diesel engines by two-zone modeling of combustion,” ASME Transactions, J.Engng for Gas Turbines and Power, Vol. 112, pp.138-149, 1990.
- Rakopoulos C.D, Hountalas D.T., “Development and validation of a 3-D Multi-zone combustion model for the prediction of DI diesel engines performance and pollutants emissions”, SAE Transactions, J.of Engines, Vol.107, Section 3, pp.1413-1429, 1998.