Wastegate control strategy in electrically assisted turbochargers: A formula student car case study

Abstract

The pursuit of reduced carbon emissions has spurred powertrain innovations, especially in the automotive sector. This study aims to numerically analyze the electrically assisted turbocharging (eTurbo) on internal combustion engines (ICEs) with a specific focus on optimizing wastegate control across diverse engine speeds. Results highlight the significant influence of wastegate settings on critical parameters such as brake-specific fuel consumption (BSFC), power, and torque. Through meticulous simulations and validation, the study identifies optimal wastegate configurations for different engine speeds. Precision control is shown to have a profound impact on BSFC, power, torque, and overall efficiency. Additionally, findings underscore the dynamic nature of eTurbo performance, emphasizing the importance of customized control strategies. The naturally aspirated model is validated with real-world data from a Honda CBR600RR engine integrated into a Formula Student vehicle powertrain, meeting competition regulations. Torque measurements obtained from a chassis dynamometer reveal a maximum relative error of 8%. A dynamic control strategy is proposed to adapt wastegate adjustments in real-time based on engine conditions, aiming to enhance system efficiency and performance, contributing to improved engine efficiency and sustainable transportation solutions. The steady state simulation results demonstrate that wastegate adjustments significantly improve performance, enhancing engine brake power, volumetric efficiency, Engine Brake Specific Fuel Consumption (BSFC), and Equivalent Brake Specific Fuel Consumption (EBSFC). EBSFC exhibits nuanced changes based on wastegate configurations and engine speeds. At a turbocharger speed of 140,000 rpm, the EBSFC drops by 2.8% at 40% wastegate opening and 10,000 rpm engine speed, while it drops by 2.5% at 20% wastegate opening and 12,000 rpm.