Application of Energy Flow Analysis into Vehicle Fuel Economy Optimization Using 1-D Simulation

【摘要】：Usually,vehicle fuel economy simulation model can be just used in simply analysis under relatively stable operating conditions.However,the operating boundary of the vehicle fuel consumption test cycle is a transient process.In order to improve the simulation model's accuracy on predicting and analyzing the vehicle fuel economy performance,a model that can realize the simulation under complex operating boundaries is necessary.What's more,the increasingly stringent fuel consumption regulation requires an efficient and economical vehicle fuel economy development solution.This paper proposes a vehicle fuel economy optimization platfor,(VFEOP) with the application of "Energy Flow Analysis"in GTSUITE.VFEOP is composed of multiple sub models:engine thermodynamic model,engine block,cooling circuit,lubricating circuit,engine mechanical friction model,underhood model,transmission and vehicle model,electric model,ECU,TCU(lock-up control,shifting control),driver,gearbox lubricating model,signal,monitor,data output.VFEOP considers detailed physical parameters,control strategies and couple connects of different systems.This makes it possible to carry out fuel optimizing simulation with Energy Flow Analysis concept.Besides,VFEOP can also study warming up characteristics and performances of thermodynamics,engine block,cooling circuit,lubricating circuit,engine mechanical friction and so on.Above all,these sub models are mainly physical models and they are integrated together to provide multi-system coupling fuel consumption performance analysis.To ensure the precision of the integrated model,at least 100 parameters measured in the whole vehicle condition are necessary for the model calibration,and the results output by the integrated model are in a good agreement with the test data.The integrated model has been used to study transient performance of the vehicle under the cold-start NEDC cycle.Also,a benchmark analysis of strategies optimization(e.g.DFCO,catalyst light-off,VVT,etc.),flow adjustment of cooling and lubricating circuit,thermal management optimization(e.g.High efficiency engine oil cooler,electronic thermostat,switchable water pump,etc.) between a basic vehicle and a benchmark vehicle is carried out based on VFEOP,the conclusions are the catalyst light-off strategy with its corresponding shifting strategy affect up to 3.86% fuel consumption,DFCO strategy affects up to 2%,the AT gearbox energy loss under idling condition affects above 1%,increasing heating-up speed of heat exchanger components without increase upper temperature levels affects negligible.Based on the VFEOP,we can predict a vehicle's fuel performance under the cold-start NEDC cycle directly,and from the application case in this paper we can know that:controlling strategies optimization has the potential to reduce fuel consumption as much as 7.25% without increasing costs,thermal management solutions should be considered comprehensively to reduce fuel consumption.