Nonlinear modelling and control of a common rail injection system for diesel engines

Abstract

Modern trends in designing mechatronic systems call for a synergic design of the separated subsystems (mechanic, electronic parts, control modules, etc.) concurring to the overall performance. Following this point of view, this paper presents a control oriented model and a nonlinear control design for a Common Rail injection system. First a model is developed, which is tuned in a virtual simulation environment, representing the injection system in details in a reliable replication of reality. Then a sliding mode control is developed. Both the model of the injection process and of the control law are validated by a virtual detailed simulation environment. The prediction capability of the model and the control efficiency are clearly shown.

Multi-Domain Modelling and Control in Mechatronics: the Case of Common Rail Injection Systems

“…with β 0 > 0 coping with uncertainties (Lino et al, 2007). This ensures that 0 ≤ s s , so that all the trajectories starting off the sliding surface reach it in finite time and those on the surface cannot leave it.…”

“…To compensate the rail pressure drop Δp r caused by the injection occurring within the angular interval [180°, 360°] during regulator inactivity, a compensation term is introduced in the pressure reference which is derived from the injection flow equation. Thus, the new pressure reference becomes P r -Δp r (Lino et al, 2007).…”

“…In fact, considering too many details and a high number of adjustable parameters make the design of the control law quite difficult. Hence, to this aim, a lumped parameter nonlinear model is considered (Lino et al, 2007), which is suitable for control purposes and can be adapted to different injection systems with the same architecture. The model is validated by simulation, using the package AMESim.…”

“…The model is expressed in state space form, where the pump pressure p p and the common rail pressure p r are the state variables, while the camshaft angular position θ and speed ω rpm , the regulator exciting signal u and the injectors driving signal E T are the inputs. Assuming, without loss of generality, that no reversal flows occur, the state space representation is (Lino et al, 2007): …”

Research on the Common Rail Pressure Overshoot of Opposed-Piston Two-Stroke Diesel Engines

“…That is, research on control algorithms is influenced by the whole fuel injection system, so it is necessary to establish a control-oriented model of a common rail injection system. Paolo et al [23,24] built a flow nonlinear equilibrium model of common rail systems, and a simplified model of the internal rail flow from the perspective of engineering practice. They also came up with a simplified model of a sliding mode control method and figured that the method was appropriate for stability control of the common rail system nonlinear characteristics.…”