Gasoline Engine Idle Speed Control Method;gasoline Engine Idle Speed Control Method

Gasoline engine idle condition is one of the important conditions, about 30% of gasoline fuel was consumed in the idle condition, so gasoline engine idle condition of the control has been a hot spot. The main purpose of idle speed control is to meet the emissions of gasoline engine idle speed based on engine speed to stabilize at the desired speed. Engine idle condition is affected by a variety of external torque, which is the main four: air conditioning, power steering, transmission gear and alternator. These changes in the external torque could cause the engine speed fluctuation, even lead to engine stalling, so when the engine idle speed on the interference rejection capability is particularly important.In this paper, a gasoline engine of the average model of four-cylinder engine is as the research object. It will use the German engine simulation software enDYNA to verify the validity of change model. Then throttle angle and spark advance are selected as the control inputs, engine speed and intake manifold pressure as state variables, engine speed as output, the model is two-input single-output system state equation. The non-linear mathematical model of the engine will be linearized in the reference point, and use the nonlinear model to verify the validity of the linear model.This linear model of the engine, was designed based on LMI's input constrains state feedback controller. As in the design of the controller, there is conservative, makes the interference suppression system is also deficient. Therefore, this article also designed for MIMO system disturbance observer (DOB) of the controller, the system is designed so that the H_∞state feedback control and disturbance observer composite controller. Simulation experiment considered four disturbance torques, respectively, in the open-loop, input constraints state feedback controller, input constraints H_∞state feedback control with disturbanceobserver under the conditions of the composite controller, the simulation results show that the H_∞control and DOBC can effectively suppress the interference effects on system performance, improve the robustness of the system.