Modeling the Spark Ignition Engine Warm-Up Process to Predict Component Temperatures and Hydrocarbon Emissions

During port-fuel–injected (PFI) spark-ignition (SI) engine startup and warm-up fuel accounting continues to be a challenge. Excess fuel must be injected for a near stoichiometric combustion charge. The “extra” fuel that does not contribute to the combustion process may stay in the intake port or as liquid films on the combustion chamber walls. Some of this combustion chamber wall liquid fuel is transported to the engine’s oil sump and some of this liquid fuel escapes combustion and evolves during the expansion and exhaust strokes. Experiments were performed to investigate and quantify this emerging in-cylinder fuel vapor post-combustion cycle by cycle during engine startup. It is believed that this fuel vapor is evaporating from cylinder surfaces and emerging from cylinder crevices. A fast in-cylinder diagnostic, the fast flame ionization detector, was used to measure this behavior. Substantial post-combustion fuel vapor was measured during engine startup. The amount of post-combustion fuel vapor that develops relative to the in-cylinder precombustion fuel charge is on the order of one for cold starting (0 °C) and decreases to ∼13 for hot starting engine cycles. Fuel accounting suggests that the intake port puddle forms quickly, over the first few engine cranking cycles. Analysis suggests that sufficient charge temperature and crevice oxygen exists to at least partially oxidize the majority of this post-combustion fuel vapor such that engine out hydrocarbons are not excessive.

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The Effect of Using 30% Iso-Butanol-Gasoline Blend on Hydrocarbon Emissions from a Spark-Ignition Engine

Energy Sources ◽

10.1080/00908319950014704 ◽

1999 ◽

Vol 21 (5) ◽

pp. 379-394 ◽

Cited By ~ 44

Author(s):

F. N. Alasfour

Keyword(s):

Spark Ignition ◽

Spark Ignition Engine ◽

Hydrocarbon Emissions

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Effect of Fuel Parameters on Speciated Hydrocarbon Emissions from a Direct Injection Spark Ignition Engine

10.4271/2000-01-1908 ◽

2000 ◽

Cited By ~ 4

Author(s):

Chad Stovell ◽

Ronald D. Matthews ◽

Yiqun Huang ◽

B. E. Johnson ◽

Bob Larsen ◽

...

Keyword(s):

Direct Injection ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Hydrocarbon Emissions ◽

Direct Injection Spark Ignition

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Two-Stage Lean-Burn Combustion Inside a Natural-Gas Spark-Ignition Engine With a Bowl-in-Piston Chamber

ASME 2019 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2019-7181 ◽

2019 ◽

Author(s):

Jinlong Liu ◽

Cosmin E. Dumitrescu

Keyword(s):

Natural Gas ◽

Combustion Chamber ◽

Combustion Process ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Intake Manifold ◽

Hydrocarbon Emissions ◽

Fuel Injector ◽

Unburned Hydrocarbon ◽

Piston Chamber

Abstract The conversion of existing diesel engines to spark ignition (SI) operation by adding a low-pressure injector in the intake manifold for fuel delivery and replacing the original high-pressure fuel injector with a spark plug to initiate and control the combustion process can reduce U.S. dependence on petroleum imports and increase natural gas (NG) applications in heavy-duty transportation sectors. Since the conventional diesel combustion chamber (i.e., flat-head-and-bowl-in-piston-chamber) creates high turbulence, the converted NG SI engine can operate leaner with stable and repeatable combustion process. However, existing literatures point to a long late-combustion duration and increased unburned hydrocarbon emissions in such retrofitted engines that maintained the original combustion chamber. Consequently, the main objective of this paper was to report recent findings of NG combustion characteristics inside a bowl-in-piston combustion chamber that will add to the general understanding of the phenomena. The new results indicated that the premixed NG burn inside the bowl-in-piston combustion chamber will separate into a bowl-burn and a squish-burn processes in terms of burning location and timing. The slow burning event in the squish region explains the low slope of the burn rate towards the end of combustion in existing studies (hence the longer late-combustion period). In addition, the less-favorable conditions for the combustion in the squish region explained the increased carbon monoxide and unburned hydrocarbon emissions.

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