0D/1D Thermo-Fluid Dynamic Modeling Tools for the Simulation of Driving Cycles and the Optimization of IC Engine Performances and Emissions

Andrea Marinoni,Tarcisio Cerri,Emanuele Piatti,Enrico Ernesto Pisoni,Matteo Tamborski,Gianluca Montenegro,Angelo Onorati,Gianluca D’Errico

doi:10.3390/app11178125

Abstract

The prediction of internal combustion engine performance and emissions in real driving conditions is getting more and more important due to the upcoming stricter regulations. This work aims at introducing and validating a new transient simulation methodology of an ICE coupled to a hybrid architecture vehicle, getting closer to real-time calculations. A one-dimensional computational fluid dynamic software has been used and suitably coupled to a vehicle dynamics model in a user function framework integrated within a Simulink® environment. A six-cylinder diesel engine has been modeled by means of the 1D tool and cylinder-out emissions have been compared to experimental data. The measurements available have been used also to calibrate the combustion model. The developed 1D engine model has been then used to perform driving cycle simulations considering the vehicle dynamics and the coupling with the energy storage unit in the hybrid mode. The map-based approach along with the vehicle simulation tool has also been used to perform the same simulation and the two results are compared to evaluate the accuracy of each approach. In this framework, to achieve the best simulation performance in terms of computational time over simulated time ratio, the 1D engine model has been used in a configuration with a very coarse mesh. Results have shown that despite the high mesh spacing used the accuracy of the wave dynamics prediction was not affected in a significant way, whereas a remarkable speed-up factor was achieved. This means that a crank angle resolution approach to the vehicle simulation is a viable and accurate strategy to predict the engine emission during any driving cycle with a computation effort compatible with the tight schedule of a design process.

Highlights

Nowadays internal combustion engines play a crucial role in worldwide mobility.A general concern about climate change imposes the adoption of an environmentally sustainable policy, as well relevant efforts towards a reduction of fuel consumption and compliance with strict emission regulations [1,2]
This research work focused on the prediction of fuel consumption of a Diesel heavyduty engine in real driving cycles, by means of computer simulations
As investigated in previous works, the map-based approach, to represent the IC engine characteristics within a vehicle model, can be very fast but it could provide poor results in terms of fuel consumption and pollutants emissions, especially with new and demanding test cycles

Summary

Introduction

Nowadays internal combustion engines play a crucial role in worldwide mobility.A general concern about climate change imposes the adoption of an environmentally sustainable policy, as well relevant efforts towards a reduction of fuel consumption and compliance with strict emission regulations [1,2]. Cylinder pressure, fuel consumption and emissions), being able to represent every operating condition just starting from a few operating points analyzed in the experimental laboratory (map-based approach) [5,6]. State of the art 1D simulation models can calculate the steady-state engine maps This is a very powerful and fast simulation approach, but the hypothesis of steady state working condition represents a major limitation. A robust simulation method is required to account for the transient conditions of the IC engine coupled to the vehicle and its components, to obtain more realistic results in terms of fuel consumption and emissions [7]

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