A hybrid electric vehicle energy optimization strategy by using fueling control in diesel engines

This paper addresses a control scheme for a parallel hybrid vehicle powertrain by introducing fueling control techniques. Since a diesel engine is involved in the proposed configuration, the control of fuel injection mass and timing becomes a crucial issue. In this study, these two variables are selected as control inputs for the hybrid powertrain system. Meanwhile, an optimization-based control strategy is designed to solve the hybrid electric vehicle power management problem by incorporating engine brake specific fuel consumption characteristics with regard to fuel injection control variables. To show the advantages of the proposed control scheme, another optimization-based strategy with fixed fuel injection timing is developed and implemented for comparison. The influence of NOx emission is also considered in control strategy and simulation results to show that the proposed fuel control technique has limited impact on NOx emission but imposes a considerable improvement on fuel saving.

Modeling and Analysis of Fuel Injection Split for Diesel Engine Active Fueling Control

With the improvements in Diesel engine injection systems, the fueling-path, which is more accurate, flexible, and faster than the air-path, can be actively utilized in conventional and advanced combustion mode controls, especially for enhancing the combustion transient performance. In this paper, fuel injection split models are proposed to describe the relationship between fuel split ratio and two combustion outputs, i.e., the crank angle at 50% heat released (CA50) and the indicated mean effective pressure (IMEP). The model parameters are related to the engine in-cylinder thermal boundary conditions, referred to as the in-cylinder conditions (ICCs). The models were verified by engine experimental data with identical and different ICCs under different engine operating conditions. Such models can be potentially utilized in active fueling control for Diesel engine combustion control, and therefore benefit engine fuel efficiency and reduce engine-out emissions.

Transient Fueling Controller Identification for Spark Ignition Engines

Presented in this paper is a feedforward fueling controller identification methodology for the transient fueling control of spark ignition (SI) engines. The hypothesis of this work is that the feedforward fueling control of SI engines can be separated into steady state and transient phenomena and that the majority of the nonlinear behavior associated with engine fueling can be captured with nonlinear steady state models. The proposed transient controller identification process is built from standard nonparametric identification techniques followed by parametric model recovery. Crank angle serves as the independent variable for these models. Two separate system identification problems are solved to identify the air path dynamics and the fueling path dynamics. The transient feedforward controller is then calculated as the ratio of the air path-over-the fueling path dynamics thereby coordinating the engine fueling with the air path dynamics. It will be shown that a linear transient feedforward-fueling controller operating in tandem with a nonlinear steady state fueling controller can achieve air-fuel ratio regulation comparable to the production fueling controller without the extensive controller calibration process. The engine used in this investigation is a 1999 Ford 4.6L V-8 fuel injected engine.

Data Driven Feedforward Transient Fueling Controller Identification for Spark Ignition Engines

Presented in this paper is a feedforward fueling controller identification methodology for the transient fueling control of spark ignition (SI) engines. The proposed transient feedforward controller is identified and executed in the crank angle domain, and operates in tandem with a steady state fueling controller. The hypothesis is that the feedforward fueling control of SI engines can be separated into steady state and transient phenomena, and that the majority of the nonlinear behavior associated with engine fueling can be captured with nonlinear steady state compensation. The proposed transient controller identification process is built from standard nonparametric identification techniques using spectral density functions where crank angle serves as the independent variable. Two separate system identification problems are solved to identify the air path dynamics and the fuel path dynamics. The transient feedforward controller is then calculated as the ratio of the air path-over-the fuel path dynamics so that the fuel path dynamics match the air path dynamics. Consequently fueling is coordinated with the fresh air charge during transient conditions. It will be shown that a linear transient feedforward-fueling controller operating in tandem with a nonlinear steady state fueling controller can achieve air-fuel ratio (AFR) regulation comparable to a production controller without the extensive controller calibration process. The engine used in this investigation is a 1999 Ford 4.6L V-8 fuel injected engine.

Transient Air/Fuel Ratio Controller Identification Using Repetitive Control

Presented in this paper is a feedforward controller identification process for the transient fueling control of spark ignition (SI) engines. The objective of an SI fueling control system is to guarantee a prespecified air–fuel (A/F) ratio, despite changing driver demands commanded through the throttle. The controller identification process is based on standard system identification tools and is comprised of three steps. The first step involves the design and implementation of a repetitive feedback controller. Next, the engine is subjected to a prespecified periodic throttle motion for which the repetitive controller achieves precise A/F control as t→∞. Finally, using the engine speed, the mass air flow, and the fuel pulsewidth information during precise fueling conditions, the feedforward fueling controller is identified using standard parametric system identification tools. This identification process can be performed during engine warm-up, thereby enabling a rapid determination of the fueling requirements as a function of temperature. Experimental validation is provided on a 1999 Ford 4.6L V-8 fuel injected engine with sequential port injection.