  A significant challenge in the development of control systems for diesel
airpath applications is to tune the controller parameters to achieve
satisfactory output performance, especially whilst adhering to input and safety
constraints in the presence of unknown system disturbances. Model-based control
techniques, such as model predictive control (MPC), have been successfully
applied to multivariable and highly nonlinear systems, such as diesel engines,
while considering operational constraints. However, efficient calibration of
typical implementations of MPC is hindered by the high number of tuning
parameters and their non-intuitive correlation with the output response. In
this paper, the number of effective tuning parameters is reduced through
suitable structural modifications to the controller formulation and an
appropriate redesign of the MPC cost function to aid rapid calibration.
Furthermore, a constraint tightening-like approach is augmented to the control
architecture to provide robustness guarantees in the face of uncertainties. A
switched linear time-varying MPC strategy with recursive feasibility guarantees
during controller switching is proposed to handle transient operation of the
engine. The robust controller is first implemented on a high fidelity
simulation environment, with a comprehensive investigation of its calibration
to achieve desired transient response under step changes in the fuelling rate.
An experimental study then validates and highlights the performance of the
proposed controller architecture for selected tunings of the calibration
parameters for fuelling steps and over drive cycles.
