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Understanding Catalyst Overheating Protection (COP) as a Source of Post-TWC Ammonia Emissions from Petrol Vehicle Beijing Institute of Technology
- Format:
- Book
- Conference/Event
- Author/Creator:
- Wang, Xin, author.
- Conference Name:
- SAE Powertrains, Fuels & Lubricants Conference & Exhibition (2022-09-06 : Krakow, Poland)
- Language:
- English
- Physical Description:
- 1 online resource cm
- Place of Publication:
- Warrendale, PA SAE International 2022
- Summary:
- TWC exposure to extreme temperature could result in irreversible damage or thermal failure. Thus, a strategy embedded in the engine control unit (ECU) called catalyst overheating protection (COP) will be activated to prevent TWC overheating. When COP is activated, the command air-fuel ratio will be enriched to cool the catalyst monolith down.Fuel enrichment has been proven a main prerequisite for ammonia formation in hot TWCs as a by-product of NOx reduction. Hence, COP events could theoretically be a source of post-catalyst ammonia from petrol vehicles, but this theory is yet to be confirmed in published literature. This paper validated this hypothesis using a self-programmed chassis-level test. The speed of the test vehicle was set to constant while the TWC temperature was raised stepwise until a COP event was activated. It is observed that at both testing speeds, the ammonia spike identified by a Fourier-transformation infrared analyzer (FTIR) spectrometer accorded well with the COP fuel enrichment command obtained with an OBD scan tool and downstream CO/THC concentrations once the TWC temperature exceeded a certain threshold. This confirms that COP events could result in excessive ammonia emission from petrol vehicles. In addition, a non-negligible impact of the presence of condensed water in the sample line on the quantification of ammonia (particularly on the decay side) was noticed, which could challenge the forthcoming legislation
- Notes:
- Vendor supplied data
- Publisher Number:
- 2022-01-1032
- Access Restriction:
- Restricted for use by site license
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