Turbocharger Map Reduction for Control-Oriented Modeling

2011 ◽  
Author(s):  
Karla Stricker ◽  
Lyle Kocher ◽  
Ed Koeberlein ◽  
D. G. Van Alstine ◽  
Greg Shaver
Keyword(s):  
Control Systems ◽  
Exchange Process ◽  
Variable Geometry ◽  
Shaft Speed ◽  
Analytical Functions ◽  
Nozzle Position ◽  
Mass Flows ◽  
Estimation And Control ◽  
Gas Exchange Process ◽  
And Control

The gas exchange process in a modern diesel engine is generally modeled using manufacturer-provided performance maps that describe mass flows through, and efficiencies of, the turbine and compressor. These maps are typically implemented as look-up tables requiring multiple interpolations based on pressure ratios across the turbine and compressor, as well as the turbocharger shaft speed. In the case of variable-geometry turbochargers, the nozzle position is also an input to these maps. This method of interpolating or extrapolating data is undesirable when modeling for estimation and control, and though there have been several previous efforts to reduce dependence on turbomachinery maps, many of these approaches are complex and not easily implemented in engine control systems. As such, the aim of this paper is to reduce turbocharger maps to analytical functions for models amenable to estimation and control.

Turbocharger Map Reduction for Control-Oriented Modeling

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Karla Stricker ◽  
Lyle Kocher ◽  
Ed Koeberlein ◽  
D. G. Van Alstine ◽  
Gregory M. Shaver
Keyword(s):  
Control Systems ◽  
Exchange Process ◽  
Shaft Speed ◽  
Analytical Functions ◽  
Nozzle Position ◽  
Mass Flows ◽  
Estimation And Control ◽  
Gas Exchange Process ◽  
And Control ◽  
General Success

Models of the gas exchange process in modern diesel engines typically use manufacturer-provided maps to describe mass flows through, and efficiencies of, the turbine and compressor based on pressure ratios across the turbine and compressor, as well as the turbocharger shaft speed, and in the case of variable-geometry turbochargers, the nozzle position. These look-up maps require multiple interpolations to produce the necessary information for turbocharger performance, and are undesirable when modeling for estimation and control. There have been several previous efforts to reduce dependence on maps with general success, yet many of these approaches remain complex and are not easily integrated into engine control systems. The focus of this paper is the reduction of turbomachinery maps to analytical functions that are amenable to estimator and control design, and have been validated against manufacturer-provided turbomachinery data.

Control-Oriented Gas Exchange Model for Diesel Engines Utilizing Variable Intake Valve Actuation

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Lyle Kocher ◽  
Ed Koeberlein ◽  
Karla Stricker ◽  
D. G. Van Alstine ◽  
Greg Shaver
Keyword(s):  
Gas Exchange ◽  
Diesel Engines ◽  
Exchange Process ◽  
Exhaust Gas ◽  
Intake Valve ◽  
Physically Based ◽  
Valve Position ◽  
Gas Exchange Process ◽  
And Control ◽  
Valve Actuation

Modeling and control of the gas exchange process in modern diesel engines is critical for the promotion and control of advanced combustion strategies. However, most modeling efforts to date use complex stand-alone simulation packages that are not easily integrated into, or amenable for the synthesis of, engine control systems. Simpler control-oriented models have been developed; however, in many cases, they do not directly capture the complete dynamic interaction of air handling system components and flows in multicylinder diesel engines with variable geometry turbocharging (VGT), high pressure exhaust gas recirculation (EGR), and flexible intake valve actuation. Flexibility in the valvetrain directly impacts the gas exchange process not only through the effect on volumetric efficiency but also through the combustion process and resulting exhaust gas enthalpy utilized to drive the turbomachinery. This paper describes a low-order, five state model of the air handling system for a multicylinder variable geometry turbocharged diesel engine with cooled EGR and flexible intake valve actuation, validated against 286 steady state and 62 transient engine operating points. The model utilizes engine speed, engine fueling, EGR valve position, VGT nozzle position, and intake valve closing (IVC) time as inputs to the model. The model outputs include calculation of the engine flows as well as the exhaust temperature exiting the cylinders. The gas exchange model captures the dynamic effects of the not only the standard air handling actuators (EGR valve position and VGT position) but also IVC timing, exercised over their useful operating ranges. The model's capabilities are enabled through the use of analytical functions to describe the performance of the turbocharger, eliminating the need to use look-up maps; a physically based control-oriented exhaust gas enthalpy submodel and a physically based volumetric efficiency submodel.

Modeling and Control of a Hybrid Opposed Piston Engine

2021 ◽  
Author(s):  
Joseph Drallmeier ◽  
Jason B. Siegel ◽  
Robert Middleton ◽  
Anna G. Stefanopoulou ◽  
Ashwin Salvi ◽  
...  
Keyword(s):  
Exchange Process ◽  
Tracking Error ◽  
Control Input ◽  
Hybrid Architecture ◽  
Electric Motors ◽  
Linear Quadratic ◽  
Modeling And Control ◽  
1D Model ◽  
Gas Exchange Process ◽  
And Control

Abstract This paper presents the modeling and control of an opposed piston (OP) engine in a novel hybrid architecture. The OP engine was selected for this work due to the inherent thermody-namic benefits and the balanced nature of the engine. The typical geartrain required on an OP engine was exchanged for two electric motors, significantly reducing friction and decoupling the crankshafts. By using the motors to control the crankshaft motion profiles, this configuration introduces capabilities to dynamically vary compression ratio, combustion volume, and scavenging dynamics. To realize these opportunities, a model of the system capturing the instantaneous engine dynamics is essential along with methodology to regulate the crankshaft’s rotational dynamics utilizing the electric motors. The modeling presented here couples a 1D model capturing the gas exchange process during scavenging and a 0D model of the crankshaft dynamics and the heat release profile due to combustion. With the use of this model, a linear quadratic controller with reference feedforward was designed to track the crankshaft motion trajectory. Experimental results are used to validate the model and controller performance. These results highlight the sensitivity to model uncertainty at points with high cylinder pressure, leading to large differences in control input near minimum volume. The proposed controller is, however, still able to maintain tracking error for crankshaft position below ± 1 degree.

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