Development of a Zeolite-Based (HC/NOx Trap Type) Cold-Start Catalyst (CSC) for Meeting Tier4/LEV IV Tailpipe Emission Standards, Part IV

Format:

Book

Conference/Event

Author/Creator:

Xu, Lifeng, author.

Wei, Hong, author.

Zhao, Pengfei, author.

Ma, Ruibo, author.

Wang, Lin, author.

Qian, Wangmu, author.

Qian, Menghan, author.

Conference Name:

WCX SAE World Congress Experience (2026-04-14 : Detroit, Michigan, United States)

Language:

English

Subjects (All):

Exhaust emissions.

Environmental regulations and standards.

Low emission vehicles (LEV) and zero emission vehicles (ZEV).

Exhaust systems.

Nitrogen oxides.

Emissions.

Hybrid electric vehicles.

Exhaust pipes.

Local Subjects:

Exhaust emissions.

Environmental regulations and standards.

Low emission vehicles (LEV) and zero emission vehicles (ZEV).

Exhaust systems.

Nitrogen oxides.

Emissions.

Hybrid electric vehicles.

Exhaust pipes.

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2026

Summary:

This paper is a follow-up study to three preceding reports [1,2,3] that focus on the development of a β-zeolite-based hydrocarbon/nitrogen oxide (HC/NO) trap-type cold-start catalyst (CSC) a cost-efficient technical strategy for meeting the increasingly stringent vehicle tailpipe emission standards for automotive exhaust systems, including Tier 4 and LEV IV, which are to be enforced in the near future. A core challenge in meeting Tier 4 and LEV IV exhaust emission standards lies in the fact that both the SC03 and US06 test cycles commence from ambient (cold) temperatures, as opposed to the elevated (hot) starting temperatures mandated for the preceding Tier 3 and LEV III standards.In the present study, a hybrid electric vehicle (HEV) fitted with two distinct Tier 3-certified exhaust aftertreatment systemsone officially certified to Bin 30 standards and the other a Bin 20-equivalent system (non-officially certified)was subjected to testing under the cold SC03, cold US06, hot SC03, and hot US06 test cycles for the purpose of comparative analysis. To meet the Tier 4/LEV IV Bin 30 engineering target of 13.13 mg/mile for combined NO+NMHC tailpipe emissions, the HEV with the Tier 3 Bin 30 system required an approximate 64% reduction in tailpipe emissions during cold SC03 tests, while the HEV with the Tier 3 Bin 20 system needed a 52% reduction. For cold US06 tests, these two HEVs required emission reductions of 50% and 38%, respectively, to achieve the same target.The higher tailpipe emissions observed in cold tests (relative to hot tests of the same cycles) are attributed to elevated cold-start emissions. The CSCs developed in this work were applied to modify the Tier 3 Bin 20 aftertreatment system, and vehicle tests were conducted with the CSC-modified systems under both cold SC03 and cold US06 cycles. Notably, the CSCs effectively reduced cold-start tailpipe emissions (NO+NMHC) in both test cycles, enabling the HEV to meet the Tier 4/LEV IV Bin 30 engineering target of 13.13 mg/mile for NO+NMHC tailpipe emissions. Detailed emission results, along with the effects of zeolite loading and Pd loading on CSC performance, were also investigated and are discussed in this manuscript

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