Emissions Performance of Bi-fuel CNG and Bi-fuel LPG Passenger Cars Using Sequential Multi-point Injection Systems

Stodart, Andy; Aitchison, I. J. R.; Lapetz, John

doi:10.4271/2001-01-1195

Cited by 6 publications

(1 citation statement)

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“…Several investigations and engine developments have shown that compressed natural gas (CNG) is a cleaner fuel. Several manufacturers offer vehicle versions with CNG, mostly as dual-fuel design [1,2,3,4,5,6]* ) .…”

Section: Introductionmentioning

confidence: 99%

Unregulated Emissions with TWC, Gasoline & amp; CNG

Czerwiński¹,

Heeb

Zimmerli³

et al. 2010

SAE Int. J. Engines

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Analysis of non-legislated engine-emission components, with different exhaust-gas after-treatment techniques, is an important air quality objective. This paper reports the results for various nitrogen oxides, ammonia and differentiated hydrocarbons emitted at part load from a small 4-S SI-engine. It was operated with gasoline, with CNG *) and with two different three-way catalytic converters. CNG produces less HC and less aromatics. But the HC conversion rate is insufficient. This is due to the lower exhaust gas temperatures, at part load with CNG, and due to the higher stability of light HCs. CNG affects the λ-regulation window, of the investigated system, such that the NO x conversion rate is lowered. In the rich domain of the λ-regulation window, the NO & NO x emissions after catalyst were lowest, while the NH 3 formation was most intense, and vice versa. The catalyst type: precious metal, and its content, influences the conversion rates and emissions of the investigated components during light-off.

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Section: Introductionmentioning

confidence: 99%