The combination of a growing number of complex technologies in internal combustion engines (ICE) is commonplace, due to the need of complying with the tight pollutant regulations and achieving high efficiencies. Hence the work of calibration engineers is led by a constant increase in degrees of freedom in ICE design. In this research work, a wide analysis on the optimization of combined variable valve timing (VVT) and exhaust gases recirculation (EGR) strategies is developed, in order to reduce fuel consumption in a EURO 6 1.3l 4-stroke 4-cylinder, gasoline, turbocharged, direct-injection engine, also equipped with a variable nozzle turbine (VNT). For that purpose, a methodology which combines 1D engine simulations with limited experimental work was applied. First, the data from 25 experimental tests distributed into three steady engine operating conditions was used to calibrate a 1D model. Then, modeling parametric studies were performed to optimize VVT and EGR parameters. A total of 150 cases were simulated for each operating point, in which VVT settings and EGR rate were varied at iso-air mass flow and iso-intake manifold temperature. The optimization was based on finding the configuration of VVT and EGR systems which maximizes the indicated efficiency. All different cases modeled were also evaluated in terms of pumping and heat losses. Moreover, a deep assessment of instantaneous pressure traces and mass flows in intake and exhaust valves was given, to provide insights about the optimization procedure. Finally, the findings obtained by simulation were compared with the results from a design of experiments (DOE) composed of more than 300 tests, and the impact on engine fuel consumption was analyzed.

由于需要遵守严格的污染物法规并实现高效率，内燃机（ICE）中越来越多的复杂技术相结合是司空见惯的。因此，校准工程师的工作是在ICE设计中不断增加的自由度的带领下进行的。在这项研究工作中，针对混合可变气门正时（VVT）和废气再循环（EGR）策略的优化进行了广泛的分析，以减少EURO 6 1.3l四冲程4缸汽油的燃料消耗，涡轮增压直喷发动机，还配备了可变喷嘴涡轮（VNT）。为此，应用了将一维引擎模拟与有限的实验工作相结合的方法。第一的，来自25个实验测试的数据（分布到三个稳定的发动机工况中）用于校准一维模型。然后，进行建模参数研究以优化VVT和EGR参数。对于每个工作点，总共模拟了150种情况，其中在等空气质量流量和等进气歧管温度下，VVT设置和EGR率发生了变化。优化是基于找到使指示效率最大化的VVT和EGR系统的配置而进行的。还对泵送和热量损失方面的所有不同情况进行了评估。此外，还对进气门和排气门中的瞬时压力曲线和质量流量进行了深入评估，以提供有关优化程序的见解。最后，