Direct fuzzy control of idle speed in an internal combustion engine

Idle speed control is currently an important problem in production vehicles. Increasing government regulations for vehicle efficiency motivates improvements to current systems. This paper explores the idle speed control problem with a goal of lowering idle speed, rejecting torque disturbances and reducing steady state variations in engine speed at idle. The distinguishing factor in this experimental study is that modeling and control design are carried out in the crank angle domain (as opposed to the time domain). Control schemes are designed and implemented on a Ford V8 engine. The approaches compared are PID, direct fuzzy control and fuzzy model reference learning control (FMRLC). The variable being controlled is the mass air flow through the idle bypass valve. The effect of reducing sampling rate is investigated for the PID and the direct fuzzy designs. Copyright (C) 1998 IFAC.