Direct Petrol Injection System with Bosch Motronic MED 7 - Volkspage

Engine management
Closed-loop starter catalyst
This is located in the exhaust manifold.
Due to its position close to the engine, it quickly
reaches its operating temperature and
commences exhaust gas treatment. As a result,
the strict exhaust emission limits can be met.
Closed-loop catalyst
Task
The closed-loop starter catalyst catalytically
converts the pollutants produced by combustion
into non-toxic substances.
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This is how it works
Homogeneous charge operation
at lambda = 1
The hydrocarbons (HC) and the carbon
monoxides (CO) react with oxygen (O) to oxidise
the nitrogen oxides (NOx) to form water (H 2 O)
and carbon dioxide (CO 2 ).
The nitrogen oxides are simultaneously reduced
to nitrogen (N 2 ) by this reaction.
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In stratified charge mode and in homogeneous
lean charge mode at lambda > 1
The hydrocarbons and the carbon dioxides
preferably oxidise with the oxygen which is
present in abundance in the exhaust gas, and
not with the oxygen present in the nitrogen
oxides. For this reason, the nitrogen oxides are
not converted to nitrogen by a closed-loop
catalyst during lean charge operation. They flow
through the closed-loop catalyst to the NOx
storage catalyst.
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