Idle air control valves, more popularly known as IAC valves, are located in the throttle body of an automobile. IAC valves are electronic motors that control the idle speed of the engine by adjusting the volume of air that enters the throttle valves through the opening and closing of an air bypass passage in the throttle body. An electronic control module (the computer in the car) controls the idle air control valves through the information it receives from various sensors by determining how far in or out the valve is to adjust the engine idle speed. By comparing the information of the valves and the current idle speed of the engine, the electronic control module will either increase or decrease the idle engine speed. The IAC valve consists of a movable pintle, which is a funnel shaped tip that protrudes into an air passage. The amount of air in the pintle affects the idle speed of the engine. The pintle is driven by a gear attached to an electric stepper motor that moves the pintle and a rod connected to the pintle in and out of a passageway. If the rod and pintle are pulled into the passageway, then the airflow increases, raising the engine's idle speed; when it's pushed out, the airflow decreases, reducing the engine's idle speed.
Stepper motors are capable of highly accurate movements, enabling the positioning of the idle air control valve into one of its 125 possible steps to vary the airflow in the bypass passage. The stepper motor, also known as a step motor, in the idle air control valve divides a full rotary motion into short, incremental steps resulting in small, limited movements that are ideal for IAC valves. The short steps of the stepper motors in IAC valves occur whenever a digital pulse of electrical power is applied, making them rotate in short and steady angular movements. These types of motors are made up of four coils that have stator cups formed around each coil, magnetic rotor, valve, and seat. The electronic control module energizes each of the four coils sequentially, and with each coil that is pulsed a displacement in the pole pitch occurs where the pole pairs are repositioned mechanically, thus causing the rotor to move a single step with every electronic pulse input. These graduated positions caused by electrical windings, in turn, change the valve position slightly. The electronic control module repeats the process and keeps energizing the coils until the desired position is reached. The higher the number of the steps, the larger the opening of the valve, which allows a greater volume of air to bypass the throttle body. If the electronic control module is inoperative, then the stepper motors in IAC valves remain fixed in the step count where it last failed.
NMB motors offer numerous benefits for automotive applications like IAC valves. Stepper motors from NMB offer highly accurate positioning, which is essential for the optimal performance of idle air control valves. NMB motors are also low maintenance and extremely cost effective.
If you're looking for motors for idle control valves or other automotive applications, then look no further than NMB for reliability, low noise, long life, high efficiency. NMB can also help you create customized solutions for your applications. Want to know more? Contact NMB today!