Design and Control of a Shape Memory Alloy-Based Idle Air Control Actuator for a Mid-Size Passenger Vehicle Application

Abstract

The idle air control actuator is an important device in automotive engine management systems to reduce fuel consumption by controlling the engine's idling operation. This research proposes an innovative idle air control (IAC) actuator for vehicle applications utilizing shape memory alloy (SMA) technology. The proposed actuator leverages the unique properties of SMAs, such as the ability to undergo large deformations upon thermal activation, to achieve precise and rapid controls in the air intake of automotive engines during idle conditions. The actuator structure mechanism consists of an SMA spring and an antagonistic spring made from steel. The design process utilizes both numerical and analytical approaches. The SMA spring is electrically supplied to activate the opening process of the actuator, and its closing state does not need electricity. However, the PID controller is used to control the applied current, which reduces the time taken by the actuator to achieve the actuation strokes. It shows good operability within multiple numbers of operation cycles. Additionally, the performance of the designed actuator is evaluated through mathematical algorithms by integrating it into the engine's air intake system during idle operating conditions. The results demonstrate the effectiveness of the SMA-based actuator in achieving rapid control of the air intake through bypass, thereby improving engine idle conditions.