Engine idle speed control using actuator saturation

Presented in this paper is the design and experimental validation of a saturating engine idle speed controller for a Ford V-8 fuel injected engine. The nonmeasurable external torque disturbance perturbing engine speed is delivered from the power steering pump. The performance specification is an allowable engine speed tolerance of 140 r/min about a desired set speed of 600 r/min. The controlled input is a voltage to the bypass air valve (BPAV) which regulates the air ingested into the engine. The BPAV voltage available for engine speed regulation is bounded by 0.8 V. A frequency domain controller design methodology is used to design the controller. The performance objective is satisfied using saturation control during large engine speed transients. During steady-state operation, the controlled input is not saturated.