Development of a Simplified Diesel Particulate Filter Model Intended for an Engine Control Unit

Author(s):  
Christopher Depcik ◽  
Chenaniah Langness ◽  
Jonathan Mattson
Author(s):  
Christopher Depcik

This paper enhances an earlier publication by including the concentration equations of motion into the area-conserved one-dimensional based diesel particulate filter model. A brief historical review of the species equations is accomplished to describe this model and the pertinent physics involved. In the species equations through the wall and soot layers, the diffusion constants are modified to account for the close proximity of the porous walls and the particulate matter to the gas flowing through the accompanying layers. In addition, a review of potential options involving the diffusion velocity is accomplished to determine the effect of pressure gradients on this phenomenon. In the previous paper, the model formulation illustrated that a common assumption to make for an enthalpy difference is the use of constant pressure specific heat times a temperature difference. Because of the different heats of formation and sensible enthalpies associated with the chemical species, this assumption reviewed is found to have a related error. Finally, because each channel is treated as an open system, making the common assumption of dilute mixture simplification is reviewed and found to have an associated error.


Author(s):  
Charles E. Sprouse ◽  
Michael D. Mangus ◽  
Christopher D. Depcik

Recent legislation of engine exhaust Particulate Matter (PM) emission levels cannot be met with in-cylinder PM reduction techniques, thus resulting in the need for a Diesel Particulate Filter (DPF). Modern DPFs use a honeycomb of long channels with porous walls in order to filter PM with near 100% efficiency. They must be designed to balance trapping efficiency and pressure drop, as flow restriction decreases engine efficiency. This paper describes the construction of two Matlab models in order to predict properties within the filter. Two methods for simultaneously solving the differential conservation equations along with the algebraic ideal gas law in the inlet and outlet channels have been developed. The first method solves the channel equations by transforming the differential algebraic equations (DAEs) into an ordinary differential equation (ODE) system. In addition, a second method is developed that directly solves DAE systems of index-one. In order to link the inlet and outlet channel profiles, modeling of the wall flow is necessary. Four permeability models from different disciplines are used in Darcy’s law to determine their applicability in calculating DPF wall velocity profiles. The resulting inlet, wall, and outlet parameters are compared with published results to demonstrate each model’s accuracy.


2016 ◽  
Vol 26 (3) ◽  
pp. 325-335
Author(s):  
Dmitriy A. Galin ◽  
◽  
Pavel A. Ionov ◽  
Aleksey S. Nazarkin

CIM Journal ◽  
2015 ◽  
Vol 6 (4) ◽  
pp. 227-232 ◽  
Author(s):  
J. S. Stachulak ◽  
C. Allen ◽  
V. Hensel

2018 ◽  
Author(s):  
Z. Gerald Liu ◽  
Devin R. Berg ◽  
Thaddeus A. Swor ◽  
James J. Schauer‡

Two methods, diesel particulate filter (DPF) and selective catalytic reduction (SCR) systems, for controlling diesel emissions have become widely used, either independently or together, for meeting increasingly stringent emissions regulations world-wide. Each of these systems is designed for the reduction of primary pollutant emissions including particulate matter (PM) for the DPF and nitrogen oxides (NOx) for the SCR. However, there have been growing concerns regarding the secondary reactions that these aftertreatment systems may promote involving unregulated species emissions. This study was performed to gain an understanding of the effects that these aftertreatment systems may have on the emission levels of a wide spectrum of chemical species found in diesel engine exhaust. Samples were extracted using a source dilution sampling system designed to collect exhaust samples representative of real-world emissions. Testing was conducted on a heavy-duty diesel engine with no aftertreatment devices to establish a baseline measurement and also on the same engine equipped first with a DPF system and then a SCR system. Each of the samples was analyzed for a wide variety of chemical species, including elemental and organic carbon, metals, ions, n-alkanes, aldehydes, and polycyclic aromatic hydrocarbons, in addition to the primary pollutants, due to the potential risks they pose to the environment and public health. The results show that the DPF and SCR systems were capable of substantially reducing PM and NOx emissions, respectively. Further, each of the systems significantly reduced the emission levels of the unregulated chemical species, while the notable formation of new chemical species was not observed. It is expected that a combination of the two systems in some future engine applications would reduce both primary and secondary emissions significantly.


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