| Selective Catalytic Reduction (SCR) |
NOx Storage Reduction (NSR) Catalyst |
Advantages:
- High conversion rate up to 90%
- Technology already developed and used in stationary applications
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Advantages:
- Using HC and CO exhaust emissions as reducing agents
- Oxidation of SOF, HC, CO emissions possible due to the use of specially coated zeolite catalysts
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Disadvantages:
- Costly and large space requirements
- Injections of another substance i.e., urea/ammonia as reductant
- Dynamic dosage control of reducing agent needed
- Extra oxidation catalyst for excess ammonia and SOF necessary
- Additional urea distribution network required
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Disadvantages:
- Lower conversion rates (up to about 35% only)
- Engine/Fuel system development for providing higher HC emissions needed in order to avoid additional HC injection before catalyst
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