Optimization of an Automotive Grade Stepper Motor Idle Air Control Valve for the Small Engine Market

摘要

This paper is an insight to the challenges and technical solutions chosen for design implementation of the Gen_VII permanent magnet stepper motor. Its primary function is to be used as an Idle Air Control Valve [IACV] in a small gasoline engine with a Mechanical Throttle Body [MTB] and Electronic Fuel Injection [EFI]. Stepper motors can also be referred to as Digital Linear Actuator [DLA]. The Gen_VII DLA is a 2-phase, fixed frequency, bipolar permanent magnet style stepper motor. There is discrete mechanical rotation every time one phase polarity reversal occurs. The output shaft has a moveable insert that translates this angular rotation into discrete linear movement. The Gen_I DLA is an automotive grade stepper motor that was designed to operate as an IACV in an automotive under hood environment. It has been in production for over 20 years. It is a robust design but too large in both size and mass for use on smaller engines. The newly designed Gen_VII is targeted for IACV needs of small EFI engines. The intended application field is motorbikes of 250cc or less. The Gen_VII hooded connector shown in figure 1 is for MTB with an external electrical harness. The Gen_VII with terminals for MTB internal mounting with a printed circuit board [PCB] is shown in figure 2. There are also high potentials for use of Gen_VII designs in other applications in need of a light DLA. The development of the smaller Gen_VII stepper motor was collaborative effort from Continental locations in North America, Europe, and Asia.