The aerodynamics and heat transfer performance in the rear-mounted automobile cabin have an important influence on the engine’s safety and the operational stability of the automobile.The article uses STARCCM and GT-C...The aerodynamics and heat transfer performance in the rear-mounted automobile cabin have an important influence on the engine’s safety and the operational stability of the automobile.The article uses STARCCM and GT-COOL software to establish the 3D wind tunnel model and engine cooling system model of the internal combustion engine.At the same time,we established a 3D artificial coupling model through parameter transfer.The research results show that the heat transfer coefficient decreases with the increase of the comprehensive drag coefficient of the nacelle.This shows that the cabin flow field has an important influence on the heat transfer coefficient.Themainstream temperature rise of the engine room increases with the increase of the engine load.It is proved that vehicle speed affects the amount of heat dissipation of the engine room internal combustion engine under certain load conditions.The article provides a more effective and fast calculation method for the research on the heat dissipation of the internal combustion engine and the optimization of the cooling system equipment.展开更多
The reported discrepancy between theory and experiment for external combustion Stirling engines is explained by the addition of thermal resistance of the combustion gasses to the standard Carnot model. In these cases,...The reported discrepancy between theory and experiment for external combustion Stirling engines is explained by the addition of thermal resistance of the combustion gasses to the standard Carnot model. In these cases, the Stirling engine ideal efficiency is not as is normally reported equal to the Carnot cycle efficiency but is significantly lower. A new equation for ideal Stirling engine efficiency when the heat is obtained through external combustion without pre-heating the air, is presented and results for various fuels tabulated. The results show that petrol and diesel, internal combustion engines (Otto cycle) have a higher ideal efficiency than the Stirling engine. When comparing thermoacoustic engines heated by wood, efficiency should not be quoted as a percentage of the Carnot efficiency, but against a figure 48% lower than Carnot. The effect is not seen with electrically heated rigs, solar or nuclear fission heated engines.展开更多
Design of internal combustion engine (ICE) components is one of the earliest and also the most active areas in which computer aided modeling techniques are applied. Computer aided modeling techniques could provide req...Design of internal combustion engine (ICE) components is one of the earliest and also the most active areas in which computer aided modeling techniques are applied. Computer aided modeling techniques could provide requisite information for follow up designing segments such as structural analysis, design of technological process and manufacturing etc, and thereby lead to the reduction of product design period and the quality and reliability improvement of ICE components. So the developing situations of ICE components' 2 D drafting, 3 D modeling of ICE, overall CAD of ICE as well as component design expert system etc. are surveyed, which are the typical applications of computer aided modeling techniques in ICE component design process, and some existent problems and tasks are pointed out so as to make some references for the further research work.展开更多
Waste heat recovery is one of the possible solutions to improve the efficiency of internal combustion engines.Instead of wasting the exhaust stream of an energy conversion system into the environment,its residual ener...Waste heat recovery is one of the possible solutions to improve the efficiency of internal combustion engines.Instead of wasting the exhaust stream of an energy conversion system into the environment,its residual energy content can be usefully recovered,for example in Organic Rankine Cycles(ORC).This technology has been largely consolidated in stationary power plants but not yet for mobile applications,such as road transport,due to the limitations in the layout and to the constraints on the size and weight of the ORC system.An ORC system installed on the exhaust line of a bus powered by a natural gas spark ignition engine has been investigated.The thermal power available at engine exhaust has been evaluated by measuring gas temperature and mass flow rate during real driving operation.The waste thermal power has been considered as heat input for the ORC plant simulation.A detailed heat exchanger model has been developed because it is a crucial component for the ORC performance.The exergy analysis of the ORC was performed comparing different working fluids:R601,R1233zd(E)and two zeotropic blends of the two organic pure fluids.The model allowed the evaluation of the ORC produced energy over the driving cycle and the potential benefit on the engine efficiency.展开更多
This study is an optimized extension based on the authors’previous research on the tribo-chemical reaction under constant temperature field of two-stroke internal combustion engines(ICEs).It establishes a coupled ana...This study is an optimized extension based on the authors’previous research on the tribo-chemical reaction under constant temperature field of two-stroke internal combustion engines(ICEs).It establishes a coupled analysis model that considers the tribo-chemical reactions,dynamic contact,and interface lubrication of the piston ring-cylinder liner(PRCL)system under transient temperature conditions.In this study,for the first time,the prediction of the tribofilm thickness and its influence on the surface micro-topography(the comprehensive roughness)are coupled in the working temperature field of the PRCL system,forming an effective model framework and providing a model basis and analytical basis for subsequent research.This study findings reveal that by incorporating temperature and tribofilm into the simulation model,the average friction deviation throughout the stroke decreases from 8.92%to 0.93%when compared to experimental results.Moreover,the deviation during the combustion regime reduces from 39.56%to 7.34%.The proposed coupled model provides a valuable tool for the evaluation of lubrication performance of the PRCL system and supports the analysis software forward design in two-stroke ICEs.展开更多
At present,the dual-loop organic Rankine cycle(DORC)is regarded as an important solution to engine waste heat recovery(WHR).Compared with the conventional exergy analysis,the advanced exergy analysis can better descri...At present,the dual-loop organic Rankine cycle(DORC)is regarded as an important solution to engine waste heat recovery(WHR).Compared with the conventional exergy analysis,the advanced exergy analysis can better describe the interactions between system components and the irreversibility caused by economic or technical limitations.In order to systematically study the thermodynamic performance of DORC,the conventional and advanced exergy analyses are compared using an inline 6-cylinder 4-stroke turbocharged diesel engine.Meanwhile,the sensitivity analysis is implemented to further investigate the influence of operating parameters on avoidable-endogenous exergy destruction.The analysis result of conventional exergy analysis demonstrates that the priorities for the components that should be improved are in order of the high-temperature evaporator,the low-temperature turbine,the first low-temperature evaporator and the high-temperature condenser.The advanced exergy analysis result suggests that the avoidable exergy destruction values are the highest in the low-temperature turbine,the high-temperature evaporator and the high-temperature turbine because they have considerable endogenous-avoidable exergy destruction.The sensitivity analysis indicates that reducing the evaporation pinch point and raising the turbine efficiency can decrease the avoidable exergy destruction.展开更多
Enhancing distribution system resilience is a new challenge for researchers.Supplying distribution loads,especially the residential customers and high-priority loads after disasters,is vital for this purpose.In this p...Enhancing distribution system resilience is a new challenge for researchers.Supplying distribution loads,especially the residential customers and high-priority loads after disasters,is vital for this purpose.In this paper,the internal combustion engine(ICE)vehicles are firstly introduced as valuable backup energy sources in the aftermath of disasters and the use of this technology is explained.Then,the improvement of distribution system resilience is investigated through supplying smart residential customers and injecting extra power to the main grid.In this method,it is assumed that the infrastructure of distribution system is partially damaged(common cases)and it can be restored in less than one day.The extra power of residential customer can be delivered to other loads.A novel formulation for increasing the injected power of the smart home to the main grid using ICE vehicles is proposed.Moreover,the maximum backup duration in case of extensive damages in the distribution system is calculated for some commercial ICE vehicles.In this case,the smart home cannot deliver extra energy to the main grid because of its survivability.Simulation results demonstrate the effectiveness of the proposed method for increasing backup power during power outages.It is also shown that ICE vehicles can supply residential customers for a reasonable amount of time during a power outage.展开更多
基金The study was partly supported by the Grant SC2021ZX05A0013 of the Heilongjiang Province“hundred,thousand,thousand”Engineering Science and Technology Major Special Project.
文摘The aerodynamics and heat transfer performance in the rear-mounted automobile cabin have an important influence on the engine’s safety and the operational stability of the automobile.The article uses STARCCM and GT-COOL software to establish the 3D wind tunnel model and engine cooling system model of the internal combustion engine.At the same time,we established a 3D artificial coupling model through parameter transfer.The research results show that the heat transfer coefficient decreases with the increase of the comprehensive drag coefficient of the nacelle.This shows that the cabin flow field has an important influence on the heat transfer coefficient.Themainstream temperature rise of the engine room increases with the increase of the engine load.It is proved that vehicle speed affects the amount of heat dissipation of the engine room internal combustion engine under certain load conditions.The article provides a more effective and fast calculation method for the research on the heat dissipation of the internal combustion engine and the optimization of the cooling system equipment.
文摘The reported discrepancy between theory and experiment for external combustion Stirling engines is explained by the addition of thermal resistance of the combustion gasses to the standard Carnot model. In these cases, the Stirling engine ideal efficiency is not as is normally reported equal to the Carnot cycle efficiency but is significantly lower. A new equation for ideal Stirling engine efficiency when the heat is obtained through external combustion without pre-heating the air, is presented and results for various fuels tabulated. The results show that petrol and diesel, internal combustion engines (Otto cycle) have a higher ideal efficiency than the Stirling engine. When comparing thermoacoustic engines heated by wood, efficiency should not be quoted as a percentage of the Carnot efficiency, but against a figure 48% lower than Carnot. The effect is not seen with electrically heated rigs, solar or nuclear fission heated engines.
文摘Design of internal combustion engine (ICE) components is one of the earliest and also the most active areas in which computer aided modeling techniques are applied. Computer aided modeling techniques could provide requisite information for follow up designing segments such as structural analysis, design of technological process and manufacturing etc, and thereby lead to the reduction of product design period and the quality and reliability improvement of ICE components. So the developing situations of ICE components' 2 D drafting, 3 D modeling of ICE, overall CAD of ICE as well as component design expert system etc. are surveyed, which are the typical applications of computer aided modeling techniques in ICE component design process, and some existent problems and tasks are pointed out so as to make some references for the further research work.
基金The authors gratefully acknowledge Universitàdegli studi della Campania“L.Vanvitelli”for funding the research project CHIMERA with V:ALERE 2019 grant。
文摘Waste heat recovery is one of the possible solutions to improve the efficiency of internal combustion engines.Instead of wasting the exhaust stream of an energy conversion system into the environment,its residual energy content can be usefully recovered,for example in Organic Rankine Cycles(ORC).This technology has been largely consolidated in stationary power plants but not yet for mobile applications,such as road transport,due to the limitations in the layout and to the constraints on the size and weight of the ORC system.An ORC system installed on the exhaust line of a bus powered by a natural gas spark ignition engine has been investigated.The thermal power available at engine exhaust has been evaluated by measuring gas temperature and mass flow rate during real driving operation.The waste thermal power has been considered as heat input for the ORC plant simulation.A detailed heat exchanger model has been developed because it is a crucial component for the ORC performance.The exergy analysis of the ORC was performed comparing different working fluids:R601,R1233zd(E)and two zeotropic blends of the two organic pure fluids.The model allowed the evaluation of the ORC produced energy over the driving cycle and the potential benefit on the engine efficiency.
基金supported by the Shandong Provincial Natural Science Foundation(No.ZR2022QE183).
文摘This study is an optimized extension based on the authors’previous research on the tribo-chemical reaction under constant temperature field of two-stroke internal combustion engines(ICEs).It establishes a coupled analysis model that considers the tribo-chemical reactions,dynamic contact,and interface lubrication of the piston ring-cylinder liner(PRCL)system under transient temperature conditions.In this study,for the first time,the prediction of the tribofilm thickness and its influence on the surface micro-topography(the comprehensive roughness)are coupled in the working temperature field of the PRCL system,forming an effective model framework and providing a model basis and analytical basis for subsequent research.This study findings reveal that by incorporating temperature and tribofilm into the simulation model,the average friction deviation throughout the stroke decreases from 8.92%to 0.93%when compared to experimental results.Moreover,the deviation during the combustion regime reduces from 39.56%to 7.34%.The proposed coupled model provides a valuable tool for the evaluation of lubrication performance of the PRCL system and supports the analysis software forward design in two-stroke ICEs.
基金supported by the Science and Technology Major Project of Tibet of China(Grant No.XZ201801-GA-03)the Natural Science Foundation of Hunan Province,China(Grant No.2018JJ2399)。
文摘At present,the dual-loop organic Rankine cycle(DORC)is regarded as an important solution to engine waste heat recovery(WHR).Compared with the conventional exergy analysis,the advanced exergy analysis can better describe the interactions between system components and the irreversibility caused by economic or technical limitations.In order to systematically study the thermodynamic performance of DORC,the conventional and advanced exergy analyses are compared using an inline 6-cylinder 4-stroke turbocharged diesel engine.Meanwhile,the sensitivity analysis is implemented to further investigate the influence of operating parameters on avoidable-endogenous exergy destruction.The analysis result of conventional exergy analysis demonstrates that the priorities for the components that should be improved are in order of the high-temperature evaporator,the low-temperature turbine,the first low-temperature evaporator and the high-temperature condenser.The advanced exergy analysis result suggests that the avoidable exergy destruction values are the highest in the low-temperature turbine,the high-temperature evaporator and the high-temperature turbine because they have considerable endogenous-avoidable exergy destruction.The sensitivity analysis indicates that reducing the evaporation pinch point and raising the turbine efficiency can decrease the avoidable exergy destruction.
文摘Enhancing distribution system resilience is a new challenge for researchers.Supplying distribution loads,especially the residential customers and high-priority loads after disasters,is vital for this purpose.In this paper,the internal combustion engine(ICE)vehicles are firstly introduced as valuable backup energy sources in the aftermath of disasters and the use of this technology is explained.Then,the improvement of distribution system resilience is investigated through supplying smart residential customers and injecting extra power to the main grid.In this method,it is assumed that the infrastructure of distribution system is partially damaged(common cases)and it can be restored in less than one day.The extra power of residential customer can be delivered to other loads.A novel formulation for increasing the injected power of the smart home to the main grid using ICE vehicles is proposed.Moreover,the maximum backup duration in case of extensive damages in the distribution system is calculated for some commercial ICE vehicles.In this case,the smart home cannot deliver extra energy to the main grid because of its survivability.Simulation results demonstrate the effectiveness of the proposed method for increasing backup power during power outages.It is also shown that ICE vehicles can supply residential customers for a reasonable amount of time during a power outage.
