Study of the performance of a turbocharged engine of a ethanol using EGR to reduce NOx emissions and control knock

Author(s)

Ana Paula Mattos

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Mecânica
• Defense date: 2018-08-16

Examining board members

Waldyr Luiz Ribeiro Gallo; Rogério Gonçalves dos Santos; Pedro Teixeira Lacava; José Antonio Velázquez; Janito Vaqueiro Ferreira

• Advisor: Waldyr Luiz Ribeiro Gallo

Abstract

The use of the turbocharger with exhaust gases recirculation (EGR) in ignition engines has been a solution to increase power and at the same time to reduce the emission of NOx, and avoid knock. These two technologies are already widely used in diesel and gasoline engines, but in the ethanol engine there are few studies. A phenomenological model with two-zone was developed for the aspirated engine, which was calibrated with experimental values. The data to simulate the turbocharged with EGR engine were stipulated from studies, and typical values of the literature were used, which were adequate with the conditions analyzed. The model can simulate different engine types, as well as geometry and valve control and operating conditions. The turbocharger with EGR engine can simulate two heat exchanger configurations, the high and the low pressure. The study presented important results regarding the use of the intercooler of the turbocharger, for to reduce the tendency of detonation as in the emissions. It has also been shown that the type of EGR exchanger configuration also support in decreasing the formation of the pollutants, NOx and CO, and in engine power. The optimum amount of recirculation of gases and the amount of flow mass in waste gate depend on each operating regime. The engine using hydrous ethanol (5% water) presented better results, reconciling performance parameters with the lowest detonation rate compared to E27 (27% ethanol in the gasoline model), "Brazilian gasoline", E85 (15 % gasoline in ethanol), "US ethanol," and E100 (anhydrous ethanol). The most influential parameter to avoid detonation is to delay the ignition, but there is a significant loss of power. Reconciling the point delay of ignition with EGR and enriching the mixture obtained a better result, for a greater power and avoiding the knock. Brazilian gasoline had a later point delay of ignition so that it did not knock more in relation to the others, and the E95h was the fuel that had to delay less to leave the condition of knock of the engine. The mathematical model is a resource in studying the influence of technologies on engine performance, reducing the time and financial resources compared to experimental studies. In this work, presented optimistic results regarding the use of EGR to reduce NOx formation. And how to avoid knock of two factors that complicate the use of the turbocharged engine (AU)

• FAPESP's process: 15/03170-0 - Performance evaluation of an ethanol-fueled engine with EGR to reduce NOx emissions and to control knock
• Grantee: Ana Paula Mattos
• Support Opportunities: Scholarships in Brazil - Doctorate