A Novel Device for Cycle-Resolved Air-to-Fuel Ratio Control to Effectively Reduce Transient Engine-Out NOx Emissions

  • Harmful NOx emissions generated during rapid changes in engine’s speed and load (such as acceleration or deceleration) are strongly linked to deviations in air-to-fuel ratio (λ) from its optimal setpoint. These deviations arise under transient conditions due to several factors, including sensor resolution limitations, time delays between actuators and sensors, and inaccurate air mass estimation within the engine management system. While fuel mass control has significantly improved over the past three decades - achieving superior performance in terms of both dynamics and accuracy through the use of multiple injections per engine cycle - the primary challenge remains the precise control of air mass, particularly under transient conditions. Nonlinear wave dynamics and the inertia of the engine’s air path make traditional solutions, such as slow and inefficient actuators like the butterfly valve, inadequate. This paper introduces a novel methodology to address these limitations by developing a device that is an order of magnitude fasterHarmful NOx emissions generated during rapid changes in engine’s speed and load (such as acceleration or deceleration) are strongly linked to deviations in air-to-fuel ratio (λ) from its optimal setpoint. These deviations arise under transient conditions due to several factors, including sensor resolution limitations, time delays between actuators and sensors, and inaccurate air mass estimation within the engine management system. While fuel mass control has significantly improved over the past three decades - achieving superior performance in terms of both dynamics and accuracy through the use of multiple injections per engine cycle - the primary challenge remains the precise control of air mass, particularly under transient conditions. Nonlinear wave dynamics and the inertia of the engine’s air path make traditional solutions, such as slow and inefficient actuators like the butterfly valve, inadequate. This paper introduces a novel methodology to address these limitations by developing a device that is an order of magnitude faster than a butterfly valve while minimizing flow losses. The design philosophy is outlined, and the flow bench setup used to evaluate the performance of an instrumented prototype is presented. High-frequency data collected during testing are analyzed, and the extracted flow structure and turbulence parameters are discussed. Finally, the dynamic performance of the newly developed device is incorporated into a transient gas exchange engine model, where its capability to control λ on a cycle-resolved basis is evaluated against a conventional throttle body. Numerous studies have proven that NOx spikes during engine’s accelerations and decelerations are well correlated to λ deviations from its setpoint. The assessment of the emissions reduction strategy under transient conditions is based on the device's precision in managing λ during each engine cycle, as derived from the transient model output.show moreshow less

Export metadata

Additional Services

Search Google Scholar
Metadaten
Author:Orpheas Bikas, Fabian Großmann, Jonas Oswald, Georgios BikasORCiD
Document Type:conference proceeding (proceeding)
Language:English
Reviewed:Begutachtet/Reviewed
Release Date:2025/06/25
Konferenzangabe:13th Mediterranean Combustion Symposium MCS-13
institutes:Institut für Angewandte Wasserstoffforschung, Elektro- und Thermochemische Energiesysteme (H2Ohm)
Institut für Fahrzeugtechnik
Research Themes:Energie & Ressourcen
Verstanden ✔
Diese Webseite verwendet technisch erforderliche Session-Cookies. Durch die weitere Nutzung der Webseite stimmen Sie diesem zu. Unsere Datenschutzerklärung finden Sie hier.