As diesel emissions regulations have become more and more stringent, diesel particulate filters (DPF) have become possibly the most important and complex diesel aftertreatment device. This seminar covers many DPF-related topics using fundamentals from various branches of applied sciences such as porous media, filtration and materials sciences and will provide the student with both a theoretical as well as an applications-oriented approach to enhance the design and reliability of aftertreatment platforms. Structure, geometry, composition, performance, applications and optimizations of DPFs are some of the main topics covered in this advanced level seminar. Computer simulation techniques for analysis and optimization of DPF performance are also demonstrated.

• Discuss fundamental, moderate and advanced topics on DPF structure, geometry, composition, performance, applications and optimizations
• Formulate porosity, permeability, inertial loss coefficient, flow resistance descriptors, different particulate transport modes (diffusional, interceptive), etc. to develop models for predicting backpressure of DPF
• Recognize different modes of particulate filtration regimes in DPF
• Select, design, utilize and optimize DPF for various light duty and heavy duty aftertreatment applications
• Predict, via modeling and simulations, various important DPF performance features (backpressure, peak regeneration temperature, etc.) as well as to analyze their failure modes and thus enhance the reliability of diesel exhaust aftertreatment platform designs

• Pore space and structure definitions (definitions of relevant length scales, derivation of "pore metrics" such as correlation lengths, lineal path distributions.)
• Simplified representations of structures (unit cell models based on granular, cylindrical and composite collectors.)
• Flow resistance descriptors (Darcy permeability, Forchheimer coefficient, inertial loss coefficient as functions of wall micro-geometry, cell density, wall thickness, plug length)

• Particle transport and deposition phenomena -- Condensed vs. vapor phases in diesel exhaust; Diesel fractal soot aggregate basics; Diffusional transport; Thermophoretic transport; Direct interception mechanism; Inertial transport mechanism; Other phenomena (electrical effects, sticking, entrainment by exhaust flow)
• Continuum filtration theory -- Deep-bed filtration regime; Cake filtration regime reconstruction of filter media
• True-to-the-geometry representations (digital reconstruction of filter media, micro-flow simulation with Lattice-based techniques and discrete particle dynamics. Examples applied to granular ceramic extruded filters, sintered metal filters, foam filters and fibrous textile filters.)

• Materials aspects
  • Ceramics -- Oxide based: Cordierite, Mullite, other (Tialite/Aluminum Titanate, etc.); Non-oxide based: Recrystalized Silicon Carbide (R-SiC), Siliconized Silicon Carbide (Si-SiC), Silicon Nitride
  • Metallics (high temperature alloys) -- Sintered grains and fibers

• Configurations
  • Wall-flow honeycombs (square, triangular, symmetric vs. asymmetric channels.)
  • Pleated, foiled (sheet-based) designs
  • Fibrous, textile cartridges
  • Foam-based designs
  • Flow-through particulate collectors

• Filter backpressure/particulate loading -- Porosity, permeability, pore structure issues; Role of catalyst coatings; Filter size effects (length, diameter, cell density, wall thickness); Microstructure of soot deposits (physical and chemical properties); Soot deposition conditions and role on soot structure: Steady state, transients, cycles; Modeling aspects

• Filter Regeneration
  • Soot reactivity and structure -- Oxidation mechanisms (thermal, catalytic, NO2); Kinetic descriptions
  • Types of regeneration technologies -- Raising exhaust temperature by post-injection and/or by exhaust-port injection in combination with DOxC; Fuel borne additive-assisted regeneration; Catalyst coating-assisted regeneration; Reactive species-assisted regeneration (NO2-assisted, non-thermal plasma, etc.)
  • Simulation Techniques for Diesel Particulate Filters -- Brief history of DPF performance modeling; Backpressure -- Theory, insights and lessons; Modeling: demonstrations, validations; Regeneration -- Theory, insights and lessons; Modeling: demonstrations, validations
  • Ash Effects -- Ash production, transport, deposition and thermal history; Ash effects on filter thermal management, catalyst activities, and filter sizing

Dr. Mansour Masoudi is Manager, Advanced Powertrain Technology, at Paccar Technical Center. Throughout his career, he has carried out various engineering responsibilities working on gasoline and Diesel emission control components and systems, spray injection (fuel, DEF, ...), thermodynamic processes, engine testing, simulation and math modeling of emission reduction components and energy systems. He formerly held product Research and Development responsibilities at Corning Inc., Delphi Corp. and at Bosch Diesel Systems. Dr. Masoudi holds a M.S. in Mechanical Engineering, M.S. in Management and a Ph.D. in Mechanical and Aerospace Engineering.