Mitigating Air Flow Sensor Signal Variability to Optimize Engine Operation in Passenger Cars

The need for advanced engine control systems has grown significantly in response to stricter emission regulations and increasing consumer demand for fuel-efficient passenger vehicles. Accurate estimation of intake air flow, coupled with precise fuel control, is essential to overcoming the challenges associated with modern gasoline engine performance. Hot-wire type mass air flow (MAF) sensors are commonly used for measuring intake air flow and are typically mounted on the clean side of the air intake system to protect them from contamination and extend their operational life. Reliable air flow measurement depends on maintaining a consistent and uniform flow across various engine speeds and load conditions. However, the optimal placement of the MAF sensor is often limited by engine packaging constraints, making sensor positioning a critical factor. Incorrect installation can result in inaccurate air flow readings, which negatively impact engine performance and emissions. During the development of a new air intake system for a passenger vehicle, torque oscillations were identified across a range of engine operating conditions. These fluctuations were linked to inconsistencies in the air flow signal. To address this issue, an in-depth analysis was conducted to study air flow signal behavior across different engine speeds, using several clean-side ducting layout trials. This paper presents an extensive investigation into the influence of air flow signal variation. Various intake system designs and sensor installation strategies were assessed to minimize signal disturbances and improve the precision of air flow measurement.