Simulink Control Design™ - MathWorks

MIMO Control of Diesel Engine

This example uses systune to design and tune a MIMO controller for a Diesel engine.

The controller is tuned in discrete time for a single operating condition.

Diesel Engine Model

Modern Diesel engines use a variable geometry turbocharger (VGT) and exhaust gas

recirculation (EGR) to reduce emissions. Tight control of the VGT boost pressure and EGR

massflow is necessary to meet strict emission targets. This example shows how to design

and tune a MIMO controller that regulates these two variables when the engine operates

at 2100 rpm with a fuel mass of 12 mg per injection-cylinder.

open_system('rct_diesel')

The VGT/EGR control system is modeled in Simulink. The controller adjusts the positions

EGRLIFT and VGTPOS of the EGR and VGT valves. It has access to the boost pressure and

EGR massflow targets and measured values, as well as fuel mass and engine speed

measurements. Both valves have rate and saturation limits. The plant model is sampled

every 0.1 seconds and the control signals EGRLIFT and VGTPOS are refreshed every 0.2

seconds. This example considers step changes of +10 KPa in boost pressure and +3 g/s in

EGR massflow, and disturbances of +5 mg in fuel mass and -200 rpm in speed.

13 Control System Tuning Examples