TY - GEN
T1 - Theoretical study of the effect of speed, load and fuel injection timing on a heavy-duty dl diesel engine friction losses
AU - Zannis, Theodoros
AU - Hountalas, Dimitrios
AU - Yfantis, Elias
AU - Papagiannakis, Roussos
AU - Katsanis, Ioannis
AU - Xenis, Nikolaos
PY - 2014
Y1 - 2014
N2 - In the present study a novel detailed friction model was developed and used to examine the generation of instantaneous friction losses in a heavy-duty (HD) direct-injection (Dl) diesel engine. The developed friction model captures effectively the physical context behind frictional losses generation in piston rings, piston skirt, loaded bearings of connecting rod and crankshaft, valve train mechanism and engine auxiliaries. The newly developed friction model was incorporated into existing diesel engine diagnostic software and upon a comprehensive calibration procedure its predictive ability was evaluated against measured data at various engine speeds and loads. Having ensured that the developed friction model predicts with sufficient accuracy the cycle-averaged friction losses of the HD Dl diesel engine examined in this study, the friction model was used to assess the individual effect of engine speed and load on the instantaneous and cycle-averaged engine friction losses. The analysis of the predictions showed that the increase of engine speed results in the increase of the percentage contribution of piston rings and valve train to total mechanical losses whereas, results in reduction of the percentage contribution of loaded bearings to total friction losses and it has imperceptible influence on piston skirt and fuel injection system mechanical losses variation. The increase of engine load results in a considerable increase of the percentage contribution of piston rings to total mechanical losses whereas, results in reduction of the percentage contribution of piston skirt, loaded bearings and valve train mechanism to total friction losses. Finally, it was examined the effect of fuel injection timing (i.e. peak combustion pressure) on indicated, mechanical and brake efficiency at three different diesel engine operating conditions since the HD Dl diesel engine examined in this study has been manufactured for operating at elevated peak cylinder pressures. The most important conclusion come up from the analysis regarding peak cylinder pressure effect on diesel engine frictional losses is that the increase of brake efficiency of a HD Dl diesel engine through high advancement of fuel injection timing (i.e. increase of peak combustion pressure) is feasible up to a certain limit of peak cylinder pressure increase (in the present study up to 220 bar). For peak pressure values higher than the aforementioned limit either the invariance or the reduction of mechanical efficiency prevents the reflection of thermal efficiency increase to corresponding brake efficiency improvement.
AB - In the present study a novel detailed friction model was developed and used to examine the generation of instantaneous friction losses in a heavy-duty (HD) direct-injection (Dl) diesel engine. The developed friction model captures effectively the physical context behind frictional losses generation in piston rings, piston skirt, loaded bearings of connecting rod and crankshaft, valve train mechanism and engine auxiliaries. The newly developed friction model was incorporated into existing diesel engine diagnostic software and upon a comprehensive calibration procedure its predictive ability was evaluated against measured data at various engine speeds and loads. Having ensured that the developed friction model predicts with sufficient accuracy the cycle-averaged friction losses of the HD Dl diesel engine examined in this study, the friction model was used to assess the individual effect of engine speed and load on the instantaneous and cycle-averaged engine friction losses. The analysis of the predictions showed that the increase of engine speed results in the increase of the percentage contribution of piston rings and valve train to total mechanical losses whereas, results in reduction of the percentage contribution of loaded bearings to total friction losses and it has imperceptible influence on piston skirt and fuel injection system mechanical losses variation. The increase of engine load results in a considerable increase of the percentage contribution of piston rings to total mechanical losses whereas, results in reduction of the percentage contribution of piston skirt, loaded bearings and valve train mechanism to total friction losses. Finally, it was examined the effect of fuel injection timing (i.e. peak combustion pressure) on indicated, mechanical and brake efficiency at three different diesel engine operating conditions since the HD Dl diesel engine examined in this study has been manufactured for operating at elevated peak cylinder pressures. The most important conclusion come up from the analysis regarding peak cylinder pressure effect on diesel engine frictional losses is that the increase of brake efficiency of a HD Dl diesel engine through high advancement of fuel injection timing (i.e. increase of peak combustion pressure) is feasible up to a certain limit of peak cylinder pressure increase (in the present study up to 220 bar). For peak pressure values higher than the aforementioned limit either the invariance or the reduction of mechanical efficiency prevents the reflection of thermal efficiency increase to corresponding brake efficiency improvement.
KW - Crankcase assembly friction
KW - Diesel efficiency
KW - Friction losses
KW - Piston assembly friction
UR - http://www.scopus.com/inward/record.url?scp=84915820456&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:84915820456
T3 - Proceedings of the 27th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2014
BT - Proceedings of the 27th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2014
A2 - Zevenhoven, Ron
PB - Aabo Akademi University
T2 - 27th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2014
Y2 - 15 June 2014 through 19 June 2014
ER -