No abstract

This paper is concerned with the control of turbocharged automotive diesel engines fitted with variable geometry turbines, in particular, for the case where a feedback loop is used to control the boost pressure. Interaction between the loops governing speed and controlling boost will affect the stability of the overall system. The effect of this interaction is considered for the case of automotive diesel engines in the 200–250 kW class at peak torque speed, both with and without engine speed governing, and for the cases of idle and maximum speed governing. The effects of vehicle load, turbo-charger rotor inertia and actuator response are also considered. The analysis uses the characteristic equation of the control system to determine lines of system instability in the gain plane.