PSI - Issue 42

Ricardo Pires et al. / Procedia Structural Integrity 42 (2022) 639–646 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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1. Introduction Nowadays, car manufacturers are facing adaptations to the designs of their vehicles to meet the stringent limits of particle and NOx emissions. In fact, regulations are becoming increasingly strict to combat the amount of greenhouse gas emissions emitted from road transport and recent news revealed the intention of the European Commission and the European Parliament to forbid the sailing of cars with internal combustion engines beyond 2035. Notwithstanding, the internal combustion engine (ICE) is one of the most prominent technologies created by man, as it is present in a variety of applications; however, the burning of fossil fuels is responsible for the production of greenhouse gases, including nitrogen oxides ( NO x ), which contribute to pollution levels daily. Therefore, the Exhaust Gas Recirculation (EGR) Cooler (Fig. 1a) is an efficient component used to combat the NO x levels produced during combustion without jeopardizing fuel consumption, Nies and Stolz (2001). In fact, the formation of nitrogen oxides is associated with the high temperatures reached within the combustion chamber together with the abundance of oxygen (O 2 ) and nitrogen (N 2 ) , Zheng et al. (2004). Hence, the principle of an EGR consists of recirculating a portion of the exhaust gas to the intake manifold of an engine, as exemplified in Fig. 1b, to reduce the oxygen content in the air mixture, the combustion temperature, and, therefore, the NO x formation inside the cylinders. Ladommatos et al. (1996a, 1996b, 1997a, 1997b) explain the different effects that result from applying an EGR, namely the dilution, the thermal and the chemical effects. The EGR cooler is an air-to-liquid heat exchanger that cools exhaust gas using engine coolant fluid. a b Exhaust gases

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Fig. 1. (a) EGR cooler under study; (b) Schematic representation of a High Pressure (HP) EGR cooler: ICE – Internal Combustion Engine, T Turbine, C- Compressor. Hence, the main objective of the research herein presented was to assess the impact that the distance, D, from the inner fin of the hybrid tube to the base of the baffle, Fig. 2, may cause to an EGR. As Grande et al. (2017) explain, the operating conditions it may be subjected to can be extreme due to factors such as pressure fluctuations, vibration, and, mainly, thermal cycles. These conditions have repercussions on its performance and endurance and were considered in this investigation.

Fig. 2 Section view of the EGR understudy. Values of D considered in the analyses carried out.