## 1 Introduction
Their results show that NO\({}_{x}\) emissions increase and CO emissions decrease when the O\({}_{2}\) percentage changes from 21% to 60%, at the same time that the N\({}_{2}\) concentration moves from 79% to 40%. Even with low concentrations of N\({}_{2}\), they show that the trade-off trend between NO\({}_{x}\) and soot is not easy to overcome. When the engine runs with volume proportions of 50% O\({}_{2}\) and 50% CO\({}_{2}\), without N\({}_{2}\), it is possible to solve the NO\({}_{x}\)-soot problems. The NO\({}_{x}\) emissions reach nearly zero levels in a CI engine; moreover, the study shows that the increase of O\({}_{2}\) concentration can improve the combustion performance of the engine. However, in the previous studies, the combustion system used is not specifically developed for the oxy-fuel combustion process. Consequently, a specific combustion configuration to the oxy-fuel combustion application can help to further reduce soot emissions and also compensate efficiency through the correct design of the combustion system. To apply the oxy-fuel combustion concept in combination with the MIEC in ICE, the engine must meet the operating conditions of the membrane [16]. That is, the exhaust gases of the engine, which are used to heat up the membrane, should reach the pressure and temperature requirements for optimal operation of the MIEC. [PERSON] et al. [17] studied the potential of oxy-fuel combustion in ICE to eliminate NO\({}_{x}\), CO, HC, and soot emissions. Additionally, their concept is synergistic with CO\({}_{2}\)-capture technology approaches. They proposed a 1D ICE model by using two EGR control strategies with different heat-exchanger and turbocharger disposals to recover the exhaust gas energy for the oxygen production. The oxygen production was obtained by implementing the BSCF MIEC model of [PERSON] et al. [9]. In comparison with a conventional CI engine, at high engine speeds they found that the oxy-fuel combustion system provides similar brake power and indicated efficiency. For the low engine speeds, it was noticed that the specific break fuel consumption increases. Other studies show the use of computational fluid dynamics (CFD) techniques to study oxy-fuel combustion, analyzing the combustion system performance when air is replaced by oxygen diluted in CO\({}_{2}\)[18; 19]. [PERSON] et al. [20] did a research focused on the improvement of the cycle efficiency in a CI by using the oxy-fuel combustion concept. They used CFD simulations to analyze the effect of the water injection through the injection temperature, timing and water amount on the cycle efficiency obtaining some relevant conclusions. They found that an oxy-fuel diesel engine has great potential in powertrains with high compression ratios, simultaneously delivering high efficiencies and, theoretically, zero emissions. This potential was compared against oxy-fuel HCCI and spark ignition engines performance. Moreover, the cycle efficiency and combustion process of the oxy-fuel engine can be optimized combining injection technology with waste heat recovery. Another study presented by [PERSON] et al. [21] was focused on the evaluation of the combustion characteristics of a CI engine using CFD simulations. In this work, a commercial high pressure bottle is used to supply the O\({}_{2}\), while the CO\({}_{2}\) is captured by condensation and separation of the water vapor from the exhaust gases. The gas that was introduced to the cylinder was a mixture of CO\({}_{2}\) and pure O\({}_{2}\), which was prepared in a premixing chamber. The other gases and the rest of CO\({}_{2}\) from the exhaust were compressed and stored in tanks designed for that purpose. From their simulations, they obtained a reduction in the engine power and in the thermal efficiency when the CO\({}_{2}\) concentration was increased. They attributed that behaviour to the increase of the of the heat capacity in the intake gas, decreasing the cylinder pressure and temperature.