1. Diesel Particulate Filter
COMBUSTION FUNDAMENTALS
MAE 5310
Florida Institute of Technology
Mechanical & Aerospace Department
Fall 2005
Presented by: Julien APELOIG

2. Why do we need a DPF? Diesel is use in engine combustion
Pollutant NOx is released from this combustion
Government Laws on environmental issues required reduction of these particles exhaust.

3. Diesel Fuel Properties
Gasoline
C-Range
C10H8 - C20H42
C7H16 - C9H20
Boiling Temperature (K)
>447
<373
Density (kg/m3)
850
735
Net Heating Value (MJ/L)
36.2
32.4
Compression Ratio
14:1 - 25:1
8:1 - 12:2
Injection Type
Direct
(into cylinder)
Premixed
(just before intake stroke)
Ignition Type
483 K
Spark

4. Diesel Combustion Using Decane (C10H22) Freezing Point: 243 K
Boiling Point: K
Flammable Limits in Air:
Lean: 0.75% by 326 K (F=0.56)
Lean: 5.6% by 359 K (F=4.2)
Ideal Stoichiometric Combustion:
C10H *(O2+4.76N2)  10CO2+11H2O+73.78N2

5. Principles of the DPF
Step 1: Particulate Matter-laden exhaust enters open channels.
Step 2: Ends of channels are blocked, forcing the exhaust through the porous walls.
Step 3: As gasses pass through the porous filter walls, the Particulate Matter is captured on the walls.

6. How DPF works?
The natural burning temperature of the particulate matter is around 550°C but the exhausting gas is usually at 150°C.
Using a post-injection, a post-combustion is generated in the engine, increasing the temperature by °C.
Another combustion occurs in the oxidation catalyser in front of the filter, permit an increase of 100°C .
An additive is added to the fuel to reduce the burning temperature of the particulate matter to 450°C.
All the stocked particulate matter is burn to produce only CO2, H2O, O2 and N2.

7. Questions?