Catalytic Converters CATS Flashcards
0
Q
How. 3 way cats work?
A
Metals washed on to honeycomb support of temperature stable alumina - silicate (cordie rite)
1
Q
What metals is 3 way cat based on?
A
Rh, Pt, Pd and CeO2
2
Q
What does CeO2 do?
A
Structural promoter, prevents metals and alumina from sintering and particle growth
3
Q
Compressing ignition engines (diesels)
A
Operate at low fuel/air ratio (20:1) - 100:1 than spark ignition (petrol) engines (10:1 - 20:1)
4
Q
Diesel mixture
A
Too lean to make 3 way cat work
5
Q
2 way Pt/Pd oxidation CAT needed
A
Particles not reduced so that traps are needed
6
Q
Emissions
A
Petrol, petrol+cat and diesel -> CO highest
7
Q
Emission levels
A
Petrol - highest, petrol +cat - lowest (12), diesel + oxidation cat (13)
