Control-Oriented Model for Camless Intake Process—Part I1

Abstract

The improvement of internal combustion engine is largely accomplished though the introduction of innovative actuators that allow optimization and control of the flow, mixing, and combustion processes. The realization of such a novel system depends on the existence of an operational controller that will stabilize the engine and allow experimental testing which, consequently, leads to further development of the actuator and the engine controller. This iterative process requires a starting point which is the development of a control-oriented model. Although not fully validated, the control-oriented model reveals issues associated with uncertainties, nonlinearities, and limitation of different subsystems. Moreover, it aides in defining the controller structure and the necessary parameters for the calibration of the closed loop system. In this paper (Part I) we describe the development process of a control-oriented model for a camless intake process. We first model the multicylinder crankangle-based breathing dynamics and validate it against experimental data of a conventional engine with cam-driven valve profile during unthrottled operation. We then employ the assumption of uniform air pulses during the intake duration and derive a simple input-output representation of the cylinder air charge, pumping losses and associated uncertainties that can be used for designing an electronic valvetrain controller (Part II). [S0022-0434(00)02901-4]

Control of 12-Cylinder Camless Engine with Neural Networks

“…The thermodynamic equations that describe the intake process of internal combustion engines including the 12-cyliner camless engine are based on the principles of the conservation of mass and the ideal gas law [3]. More specifically, the following relations hold for the engine cylinders .…”

“…A simulation model in Matlab software was built for the engine based on Equations (1) and (2) and implementing the implicit relations of the terms within the equations [3]. The various implicit relations include parameters that needs to be selected by comparison with real experimental engine data available from the dynamometer test at an automotive company.…”

“…The camless engine model was initiated in [3] as a result of collaboration between academia and industry. Furthermore, the basic control system of such an engine was designed in [1].…”

Inherent limitations and control design for camless engine idle speed dynamics

“…From t to t # t, the valve moves with constant acceleration, hence, t controls the peak lift of the valve. By simplifying the trapezoidal valve pro"le with an ideal rectangular pro"le, it is clear that the intake valve duration is controlled by the di!erence in the pulse timing v"t !t # t. The cylinder air charge is more sensitive to the duration rather than the lift, especially, if the lift is above 3 mm [6]. For this reason, we choose IVD as the e!ective control signal of the camless breathing process.…”

Modeling positive intake value overlap air charge response in camless engines

“…al.. 2001), and a dynamic characterization based on a Helmholtz resonator intake runner pressure model, (Moraal, 1994, Ashhab, et. al., 2000.…”