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Technical Paper

Development of the Methodology for Quantifying the 3D PM Distribution in a Catalyzed Particulate Filter with a Terahertz Wave Scanner

2014-04-01
2014-01-1573
Optimizing the performance of the aftertreatment system used on heavy duty diesel engines requires a thorough understanding of the operational characteristics of the individual components. Within this, understanding the performance of the catalyzed particulate filter (CPF), and the development of an accurate CPF model, requires knowledge of the particulate matter (PM) distribution throughout the substrate. Experimental measurements of the PM distribution provide the detailed interactions of PM loading, passive oxidation, and active regeneration. Recently, a terahertz wave scanner has been developed that can non-destructively measure the three dimensional (3D) PM distribution. To enable quantitative comparisons of the PM distributions collected under different operational conditions, it is beneficial if the results can be discussed in terms of the axial, radial, and angular directions.
Technical Paper

An Experimental Investigation into Particulate Matter Oxidation in a Catalyzed Particulate Filter with Biodiesel Blends on an Engine during Active Regeneration

2013-04-08
2013-01-0521
Active regeneration experiments were carried out on a production 2007 Cummins 8.9L ISL engine and associated diesel oxidation catalyst (DOC) and catalyzed particulate filter (CPF) aftertreatment system. The effects of SME biodiesel blends were investigated to determine the particulate matter (PM) oxidation reaction rates for active regeneration. The experimental data from this study will also be used to calibrate the MTU-1D CPF model [1]. The experiments covered a range of CPF inlet temperatures using ULSD, B10, and B20 blends of biodiesel. The majority of the tests were performed at a CPF PM loading of 2.2 g/L with in-cylinder dosing, although 4.1 g/L and a post-turbo dosing injector were also investigated. The PM reaction rate was shown to increase with increasing percent biodiesel in the test fuel as well as increasing CPF temperature.
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Catalyzed Particulate Filter Passive Oxidation Study with ULSD and Biodiesel Blended Fuel

2012-06-18
A 2007 Cummins ISL 8.9L direct-injection common rail diesel engine rated at 272 kW (365 hp) was used to load the filter to 2.2 g/L and passively oxidize particulate matter (PM) within a 2007 OEM aftertreatment system consisting of a diesel oxidation catalyst (DOC) and catalyzed particulate filter (CPF). Having a better understanding of the passive NO2 oxidation kinetics of PM within the CPF allows for reducing the frequency of active regenerations (hydrocarbon injection) and the associated fuel penalties. Being able to model the passive oxidation of accumulated PM in the CPF is critical to creating accurate state estimation strategies. The MTU 1-D CPF model will be used to simulate data collected from this study to examine differences in the PM oxidation kinetics when soy methyl ester (SME) biodiesel is used as the source of fuel for the engine.
Technical Paper

Catalyzed Particulate Filter Passive Oxidation Study with ULSD and Biodiesel Blended Fuel

2012-04-16
2012-01-0837
A 2007 Cummins ISL 8.9L direct-injection common rail diesel engine rated at 272 kW (365 hp) was used to load the filter to 2.2 g/L and passively oxidize particulate matter (PM) within a 2007 OEM aftertreatment system consisting of a diesel oxidation catalyst (DOC) and catalyzed particulate filter (CPF). Having a better understanding of the passive NO₂ oxidation kinetics of PM within the CPF allows for reducing the frequency of active regenerations (hydrocarbon injection) and the associated fuel penalties. Being able to model the passive oxidation of accumulated PM in the CPF is critical to creating accurate state estimation strategies. The MTU 1-D CPF model will be used to simulate data collected from this study to examine differences in the PM oxidation kinetics when soy methyl ester (SME) biodiesel is used as the source of fuel for the engine.
Technical Paper

Experimental Study Comparing Particle Size and Mass Concentration Data for a Cracked and Un-Cracked Diesel Particulate Filter

2009-04-20
2009-01-0629
Steady state loading characterization experiments were conducted at three different engine load conditions and rated speed on the cracked catalyzed particulate filter (CPF). The experiments were performed using a 10.8 L 2002 Cummins ISM-330 heavy duty diesel engine. The CPF underwent a ring off failure, commonly seen in particulate filters, due to high radial and axial temperature gradients. The filters were cracked during baking in an oven which was done to regenerate PM collected after every loading characterization experiment. Two different configurations i.e. with and without a diesel oxidation catalyst (DOC) upstream of the CPF were studied. The data were compared with that on an un-cracked CPF at similar engine conditions and configurations. Pressure drop, transient filtration efficiency by particle size and PM mass and gaseous emissions measurements were made during each experiment.
Technical Paper

An Experimental Study of Particulate Thermal Oxidation in a Catalyzed Filter During Active Regeneration

2009-04-20
2009-01-1474
Active regeneration experiments were performed on a Cummins 2007 aftertreatment system by hydrocarbon dosing with injection of diesel fuel downstream of the turbocharger. The main objective was to characterize the thermal oxidation rate as a function of temperature and particulate matter (PM) loading of the catalyzed particulate filter (CPF). Partial regeneration tests were carried out to ensure measureable masses are retained in the CPF in order to model the oxidation kinetics. The CPF was subsequently re-loaded to determine the effects of partial regeneration during post-loading. A methodology for gathering particulate data for analysis and determination of thermal oxidation in a CPF system operating in the engine exhaust was developed. Durations of the active regeneration experiments were estimated using previous active regeneration work by Singh et al. 2006 [1] and were adjusted as the experiments progressed using a lumped oxidation model [2, 3].
Technical Paper

The Filtration, Oxidation and Pressure Drop Characteristics of a Catalyzed Particulate Filter during Active Regeneration – A 1D Modeling Study

2009-04-20
2009-01-1274
Active regeneration of a catalyzed particulate filter (CPF) is affected by a number of parameters specifically particulate matter loading and inlet temperature. The MTU 1-D 2-Layer CPF model [1] was used to analyze these effects on the pressure drop, oxidation and filtration characteristics of a CPF during active regeneration. In addition, modeling results for post loading experiments were analyzed to understand the difference between loading a clean filter as compared to a partially regenerated filter. Experimental data obtained with a production Cummins regenerative particulate filter for loading, active regenerations and post loading experiments were used to calibrate the MTU 1-D 2-Layer CPF model. The model predicted results are compared with the experimental data and were analyzed to understand the CPF characteristics during active regeneration at 1.1, 2.2 and 4.1 g/L particulate matter (PM) loading and CPF inlet temperatures of 525, 550 and 600°C.
Technical Paper

Development of a 1-D CPF Model to Simulate Active Regeneration of a Diesel Particulate Filter

2009-04-20
2009-01-1283
A quasi-steady 1-dimensional computer model of a catalyzed particulate filter (CPF) capable of simulating active regeneration of the CPF via diesel fuel injection upstream of a diesel oxidation catalyst (DOC) or other means to increase the exhaust gas temperature has been developed. This model is capable of predicting gaseous species concentrations (HC's, CO, NO and NO2) and exhaust gas temperatures within and after the CPF, for given input values of gaseous species and PM concentrations before the CPF and other inlet variables such as time-varying temperature of the exhaust gas at the inlet of the CPF and volumetric flow rate of exhaust gas.
Technical Paper

Experimental Studies of an Advanced Ceramic Diesel Particulate Filter

2008-04-14
2008-01-0622
A Cummins ISB 5.9 liter medium-duty engine with cooled EGR has been used to study an early extrusion of an advanced ceramic uncatalyzed diesel particulate filter (DPF). Data for the advanced ceramic material (ACM) and an uncatalyzed cordierite filter of similar dimensions are presented. Pressure drop data as a function of mass loadings (0, 4, and 6 grams of particulate matter (PM) per liter of filter volume) for various flow rate/temperature combinations (0.115 - 0.187 kg/sec and 240 - 375 °C) based upon loads of 15, 25, 40 and 60% of full engine load (684 N-m) at 2300 rpm are presented. The data obtained from these experiments were used to calibrate the MTU 1-D 2-Layer computer model developed previously at MTU. Clean wall permeability determined from the model calibration for the ACM was 5.0e-13 m2 as compared to 3.0e-13 m2 for cordierite.
Technical Paper

A Methodology to Estimate the Mass of Particulate Matter Retained in a Catalyzed Particulate Filter as Applied to Active Regeneration and On-Board Diagnostics to Detect Filter Failures

2008-04-14
2008-01-0764
A methodology to estimate the mass of particulate retained in a catalyzed particulate filter as a function of measured total pressure drop, volumetric flow rate, exhaust temperature, exhaust gas viscosity and cake and wall permeability applicable to real-time computation is discussed. This methodology is discussed from the view point of using it to indicate when to initiate active regeneration and as an On-Board Diagnostic tool to detect filter failures. Steady-state loading characterization experiments were conducted on a catalyzed diesel particulate filter (CPF) in a Johnson Matthey CCRT® (catalyzed continuously regenerating trap) system. The experiments were performed using a 10.8 L 2002 Cummins ISM heavy-duty diesel engine. Experiments were conducted at 20, 60 and 75% of full engine load (1120 Nm) and rated speed (2100 rpm) to measure the pressure drop, transient filtration efficiency, particulate mass balance, and gaseous emissions.
Technical Paper

Experimental and Modeling Results Comparing Two Diesel Oxidation Catalyst - Catalyzed Particulate Filter Systems

2008-04-14
2008-01-0484
Steady-state particulate loading experiments were conducted on an advanced production catalyzed particulate filter (CPF), both with and without a diesel oxidation catalyst (DOC). A heavy-duty diesel engine was used for this study with the experiments conducted at 20, 40, 60 and 75 % of full load (1120 Nm) at rated speed (2100 rpm). The data obtained from these experiments were used and are necessary for calibrating the MTU 1-D 2-Layer CPF model. These experimental and modeling results were compared to previous research conducted at MTU that used the same engine but an earlier development version of the combination of DOC and CPF. The motivation for the comparison of the two systems was to determine whether the reformulated production catalysts performed as good or better than the early development catalysts. The results were compared to understand the filtration and oxidation differences between the two DOC+CPF and the CPF-only aftertreatment systems.
Technical Paper

A Study of the Filtration and Oxidation Characteristics of a Diesel Oxidation Catalyst and a Catalyzed Particulate Filter

2007-04-16
2007-01-1123
An experimental and modeling study was conducted to study the passive regeneration of a catalyzed particulate filter (CPF) by the oxidation of particulate matter (PM) via thermal and Nitrogen dioxide/temperature-assisted means. Emissions data in the exhaust of a John Deere 6.8 liter, turbocharged and after-cooled engine with a low-pressure loop EGR and a diesel oxidation catalyst (DOC) - catalyzed particulate filter (CPF) in the exhaust system was measured and used for this study. A series of experiments was conducted to evaluate the performance of the DOC, CPF and DOC+CPF configurations at various engine speeds and loads.
Technical Paper

An Experimental Study of Active Regeneration of an Advanced Catalyzed Particulate Filter by Diesel Fuel Injection Upstream of an Oxidation Catalyst

2006-04-03
2006-01-0879
Passive regeneration (oxidation of particulate matter without using an external energy source) of particulate filters in combination with active regeneration is necessary for low load engine operating conditions. For low load conditions, the exhaust gas temperatures are less than 250°C and the PM oxidation rate due to passive regeneration is less than the PM accumulation rate. The objective of this research was to experimentally investigate active regeneration of a catalyzed particulate filter (CPF) using diesel fuel injection in the exhaust gas after the turbocharger and before a diesel oxidation catalyst (DOC) and to collect data for extending the MTU 1-D 2-layer model to include the simulation of active regeneration. The engine used in this study was a 2002 Cummins ISM turbo charged 10.8 L heavy duty diesel engine with cooled EGR. The exhaust after-treatment system consisted of a Johnson Matthey DOC and CPF (a CCRT®).
Technical Paper

The Effect of a Diesel Oxidation Catalyst and a Catalyzed Particulate Filter on Particle Size Distribution from a Heavy Duty Diesel Engine

2006-04-03
2006-01-0877
The effect of a Johnson Matthey catalyzed continuously regenerating technology™ (CCRT®) filter on the particle size distribution in the raw exhaust from a 2002 Cummins ISM-2002 heavy duty diesel engine (HDDE) is reported at four loads. A CCRT® (henceforth called DOC-CPF) has a diesel oxidation catalyst (DOC) upstream (UP) of a catalyzed particulate filter (CPF). The particle size data were taken at three locations of UP DOC, downstream (DN) DOC and DN CPF in the raw exhaust in order to study the individual effect of the DOC and the CPF of the DOC-CPF on the particle size distribution. The four loads of 20, 40, 60 and 75% loads at rated speed were chosen for this study. Emissions measurements were made in the raw exhaust chosen to study the effect of nitrogen dioxide and temperature on particulate matter (PM) oxidation in the CPF at different engine conditions, exhaust and carbonaceous particulate matter (CPM) flow rates.
Technical Paper

The Effect of a Diesel Oxidation Catalyst and a Catalyzed Particulate Filter on the Emissions from a Heavy Duty Diesel Engine

2006-04-03
2006-01-0875
The objective of this research was to study the effects of a CCRT®, henceforth called Diesel Oxidation Catalyst - Catalyzed Particulate Filter (DOC-CPF) system on particulate and gaseous emissions from a heavy-duty diesel engine (HDDE) operated at Modes 11 and 9 of the old Environmental Protection Agency (EPA) 13-mode test cycle Emissions characterized included: total particulate matter (TPM) and components of carbonaceous solids (SOL), soluble organic fraction (SOF) and sulfates (SO4); vapor phase organics (XOC); gaseous emissions of total hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOx), nitric oxide (NO) and nitrogen dioxide (NO2), oxygen (O2) and carbon dioxide (CO2); and particle size distributions at normal dilution ratio (NDR) and higher dilution ratio (HDR). Significant reductions were observed for TPM and SOL (>90%), SOF (>80%) and XOC (>70%) across the DOC-CPF at both modes.
Technical Paper

An Experimental and Computational Study of the Pressure Drop and Regeneration Characteristics of a Diesel Oxidation Catalyst and a Particulate Filter

2006-04-03
2006-01-0266
An experimental and computational study was performed to evaluate the performance of the CRT™ technology with an off-highway engine with a cooled low pressure loop EGR system. The MTU-Filter 1D DPF code predicts the particulate mass evolution (deposition and oxidation) in a diesel particulate filter (DPF) during simultaneous loading and during thermal and NO2-assisted regeneration conditions. It also predicts the pressure drop across the DPF, the flow and temperature fields, the solid filtration efficiency and the particle number distribution downstream of the DPF. A DOC model was also used to predict the NO2 upstream of the DPF. The DPF model was calibrated to experimental data at temperatures from 230°C to 550°C, and volumetric flow rates from 9 to 39 actual m3/min.
Technical Paper

An Advanced 1D 2-Layer Catalyzed Diesel Particulate Filter Model to Simulate: Filtration by the Wall and Particulate Cake, Oxidation in the Wall and Particulate Cake by NO2 and O2, and Regeneration by Heat Addition

2006-04-03
2006-01-0467
A numerical model to simulate the filtration and regeneration performance of catalyzed diesel particulate filters (CPFs) was developed at Michigan Technological University (MTU). The mathematical formulation of the model and some results are described. The model is a single channel (inlet and outlet) representation of the flow while the thermal and catalytic regeneration framework is based on a 2-layer approach. The 2-layer model can simulate particulate matter (PM) oxidation by thermal and ‘catalytic’ means of oxidation with O2. Several improvements were made to this basic model and are described in this paper. A model to simulate PM oxidation by NO2/Temperature entering the particulate filter and oxidizing the PM in the two layers of the PM cake was developed. This model can be used to simulate the performance of filters with catalyst washcoats and uncatalyzed filters placed downstream of diesel oxidation catalysts (DOCs), as in the continuously regenerating traps, CRT's®.
Technical Paper

An Experimental and Modeling Study of a Diesel Oxidation Catalyst and a Catalyzed Diesel Particulate Filter Using a 1-D 2-Layer Model

2006-04-03
2006-01-0466
Modeling of diesel exhaust after-treatment devices is a valuable tool in the development and performance evaluation of these devices in a cost effective manner. Results from steady state loading experiments on a catalyzed particulate filter (CPF) in a Johnson Matthey CCRT®, performed with and without the upstream diesel oxidation catalyst (DOC) are described in this paper. The experiments were performed at 20, 40, 60 and 75% of full load (1120 Nm) at rated speed (2100 rpm) on a Cummins ISM 2002 heavy duty diesel engine. The data obtained were used to calibrate one dimensional (1-D) DOC and CPF models developed at Michigan Technological University (MTU). The 1-D 2-layer single channel CPF model helped evaluate the filtration and passive oxidation performance of the CPF. DOC modeling results of the pressure drop and gaseous emission oxidation performance using a previously developed model are also presented.
Technical Paper

The Effects of Two Catalyzed Particulate Filters on Exhaust Emissions from a Heavy Duty Diesel Engine: Filtration and Particulate Matter Oxidation Characteristics Studied Experimentally and Using a 1- D 2- Layer Model

2005-04-11
2005-01-0950
A 1-D 2-layer model developed previously at MTU was used in this research to predict the pressure drop, filtration characteristics and various properties of the particulate filter and the particulate deposit layer. The model was used along with dilute emission data to characterize two catalyzed particulate filters (CPFs) having different catalyst loading and catalyst application processes. The model was calibrated and validated with data obtained from steady state experiments conducted using a 1995 Cummins M11-330E heavy-duty diesel engine with manual EGR with different fuels for the two different CPFs. The two different catalyzed particulate filters were CPF III (5 gms/ft3 Pt) and CPF V (50 gms/ft3 Pt). Both the CPFs had cordierite substrates with CPF III and CPF V had MEX and NEX catalyst type formulation respectively. The CPF III filter was catalyzed using a solution-impregnated process while the CPF V filter was catalyzed using a wash coat process.
Technical Paper

The Filtration and Particulate Matter Oxidation Characteristics of a Catalyzed Wall-Flow Diesel Particulate Filter: Experimental and 1-D 2-Layer Model Results

2005-04-11
2005-01-0949
A 1-D 2-layer model developed previously at MTU was used in this research to predict the pressure drop, filtration characteristics and various properties of the particulate filter and the particulate deposit layer. The model was calibrated and validated for this CPF with data obtained from steady state experiments conducted using a 1995 Cummins M11-330E heavy-duty diesel engine with manual EGR and using ULSF. The CPF used is a NGK filter having a cordierite substrate with NEX catalyst type formulation (54% porosity, 15.0 μm mean pore diameter and 50 gms/ft3 Pt). The filter was catalyzed using a wash coat process. The model was used to predict the pressure drop, particulate mass retained inside the CPF, particulate mass filtration efficiency and concentration downstream of the CPF with agreement between the experimental and simulated data.
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