Mohammad Haghgooie

Modeling and Control of Electromechanical Valve Actuator

In this paper recent control developments for an electromechanical valve actuator will be presented. The model-based control methodology utilizes position feedback, a nonlinear observer that provides virtual sensing of the armature velocity and current, and cycleto-cycle learning. The controller is based on a nonlinear state-space description of the actuator that is derived based on physical principles and parameter identification. A bench-top experimental setup and a rapid control prototyping system are used to quantify the actuator performance. Experiments are conducted to measure valve release timing, transition times, and contact velocities for open- and closed-loop control schemes. Simulation results are presented for a feedforward cycle-to-cycle learning controller.

Output observer based feedback for soft landing of electromechanical camless valvetrain actuator

Electromechanical valvetrain (EMV) actuators can replace the camshaft allowing for electronically controlled variable valve timing (VVT) on a new generation of engines. Before EMV actuators can be used in production vehicles two critical problems need to be resolved. First, impact velocities between the valve, valve seat, and the actuator itself need to be small to avoid excessive wear on the system and ensure acceptable levels of noise. Second, the opening and closing of the valve needs to be both fast and consistent to avoid collision with the piston and to reduce variability in trapped mass. This paper presents an observer based output feedback controller designed to achieve these goals. Theoretical analysis and experimental results of the controller are provided. The experimental results show a factor of six reduction in impact velocity and consistent and quick valve timing.

Modeling and control of a spark ignition engine with variable cam timing

A control scheme is designed to minimize emissions and respond to rapid throttle changes in a fuel injected, spark ignition engine equipped with variable cam timing. The model is derived from engine mapping data for an eight cylinder experimental engine mounted in a dynamometer test cell; it is fundamentally a nonlinear and multivariable model. The control scheme jointly manages fuel and cam position.

Nonlinear Self-Tuning Control for Soft Landing of an Electromechanical Valve Actuator

Abstract Electromechanical valve actuators (EVA) can be used for electronic control of the engine valves. Their operation requires fast and precise motion of an armature between two stiff springs and two voltage-controlled electromagnets. Low contact velocities or “soft landing᾿ of the actuator on the solenoid faces and between the actuator and the valve is also necessary in order to maintain similar noise and wear levels with conventional camshaft-driven engines. We analyze the control difficulties, review the actuator model and extend our previous work by introducing impact dynamics. We then design a self-tuning nonlinear controller using extremum seeking that achieves impact velocities below 0.1 m/s and maximum transition time of 4.0 ms.

The intensity of knock in an internal combustion engine: An experimental and modeling study

Experimental data have been obtained that characterize knock occurrence times and knock intensities in a spark ignition engine operating on indolene and 91 primary reference fuel, as spark timing and inlet temperature were varied. Individual, in-cylinder pressure histories measured under knocking conditions were conditioned and averaged to obtain representative pressure traces. These averaged pressure histories were used as input to a reduced and detailed chemical kinetic model. The time derivative of CO concentration and temperature were correlated with the measured knock intensity and percent cycles knocking. The goal was to evaluate the potential of using homogeneous, chemical kinetic models as predictive tools for knock intensity.

Effects of Intake Port Design and Valve Lift on In-Cylinder Flow and Burnrate

LDA measurements of the flow in a motored engine near TDC of compression have been obtained, along with burnrate data in a firing engine having a near-central spark plug location. Results are reported for two different intake ports and four intake valve lifts varying from 25% to 100% of full lift. Opposite trends of swirl vs valve lift were found for the two ports, and the rms velocity fluctuation was found to be relatively insensitive to changes in valve lift. Regression analysis of the burn duration data was conducted, with swirl ratio and rms as independent variables. The analysis indicated that burn duration decreases with an increase in swirl ratio and/or rms velocity fluctuation. In light of the experimental findings, a new conceptual model is proposed regarding the effect of valve lift on the dissipation of turbulent velocity via changes in the length scale. And combustion-induced shear in the unburned gas resulting from conservation of angular momentum is hypothesized as a possible mechanism for increased burnrate due to swirl for the case of central ignition.

Optimization Techniques and Results for the Operating Modes of a Camless Engine

Electronic control of valve timing and event duration in a camless engine enables the optimization of fuel economy, performance, and emissions at each engine operating condition. This flexible engine technology can offer significant benefits to each of these areas, but optimization techniques become crucial to achieving these benefits and understanding the principles behind them. Optimization techniques for an 14 - 2.0L camless ZETEC dynamometer engine have been developed for a variety of areas including: Cold Starts Cylinder Deactivation Full Load Idle Transient A/F control The procedure for the optimization of each of these areas will be presented in detail, utilizing both steady state and transient dynamometer testing. Experimental data will be discussed and the principles governing the response of the engine will be explained. Selection criteria for determining an optimum strategy for the different modes will be presented and recommendations Will be discussed. Conclusions will show that a camless engine improves performance, offers significant fuel consumption benefits, improves transient control, and is beneficial in reducing emissions during the cold start and warmed up conditions.