Cold-start hydrocarbon emissions in port-injected gasoline engines

Henein, Naeim A.; Tagomori, Mauro K.

doi:10.1016/s0360-1285(99)00003-9

Cited by 78 publications

(31 citation statements)

References 88 publications

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“…In fact, characteristic time of the flame for HOQ are smaller than characteristic time of engine. Thus HOQ cannot be an important HC source for normal operating engine condition although in the case of cold start engine, HOQ produces important HC quantities [25]. Many authors agree to the fact that the main source of HC in engine are the crevices.…”

Section: Head-on Quenchingmentioning

confidence: 99%

Flame/Wall Interactions: Laminar Study of Unburnt HC Formation

Chauvy

Delhom

Réveillon

et al. 2010

Flow Turbulence Combust

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This work presents a numerical study dedicated to the formation of unburnt hydrocarbon. Two configurations: head-on quenching (HOQ) on a planar wall and in crevices, are considered. It is well known that they contribute for an important part to the sources of hydrocarbon (HC) emission in a combustion chamber. The aim of this work is to use laminar flame simulations (LFS) to understand how the unburnt HC are produced near walls in gasoline engine. A skeletal mechanism (29 species and 48 reactions) mimicking iso-octane combustion is used. In the HOQ configuration, the flame front propagates toward the cold wall where quenching occurs. The numerical procedure and the chemical scheme used in this study are first validated by comparisons with literature results for the 1D case. Several aspects of flame wall quenching such as oxidation of unburnt HC, wall heat flux, quench distances as well as HC families are investigated by varying parameters like wall temperature and equivalence ratio. In a second part, crevices are considered to study the impact of wall imperfections in combustion chambers. Configurations with different geometrical and thermodynamic properties are tested. It leads to a wide range of flame properties and HC production modes. When incomplete combustion occurs, total HC (fuel + HC) concentration can reach very high levels at the wall. When the crevice is not wide enough, the flame cannot propagate and the quantity of HC is smaller than in the case where the flame can propagate (but the fuel is not oxidizing). If the crevice is wide enough for the flame to propagate, HOQ occurs at 1 the bottom of the crevice and HC accumulate in the corners. The computational results obtained in this work demonstrate the ability of LFS to reproduce incomplete combustion mechanisms that are responsible for a major part of HC production in gasoline engines.

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Section: Head-on Quenchingmentioning

confidence: 99%

Flame/Wall Interactions: Laminar Study of Unburnt HC Formation

Chauvy

Delhom

Réveillon

et al. 2010

Flow Turbulence Combust

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“…Therefore, HC emissions increase. Meanwhile, unburned mixture trapped in the clearance gap around the piston during compression stroke returns to the burned mixture during the expansion stroke; however, the temperature of burned mixture is not high enough and oxidation effect becomes weak, which also contribute large amounts of unburned HC [5][6][7][8][9]. Figure 7 shows the curves of HC and CO emissions, the AFR (a), the speed (n) and the exhaust gas temperature (T e ) within the first 200 s after cold start.…”

Section: Cold-start Emission Characteristicsmentioning

confidence: 99%

Combustion characteristics of SI engine fueled with methanol-gasoline blends during cold start

Song

Hu²,

Liu

et al. 2008

Front. Energy Power Eng. China

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A 3-cylinder port fuel injection (PFI) engine fueled with methanol-gasoline blends was used to study combustion and emission characteristics. Cylinder pressure analysis indicates that engine combustion is improved when methanol is added to gasoline. With the increase of methanol, the flame developing period and the rapid combustion period are shortened, and the indicated mean effective pressure increases during the first 50 cycles. Meanwhile, a novel quasi-instantaneous sampling system was designed to measure engine emissions during cold start and warm-up. The results at 5uC show that unburned hydrocarbon (UHC) and carbon monoxide (CO) decrease remarkably. Hydrocarbon (HC) reduces by 40% and CO by 70% when fueled with M30 (30% methanol in volume). The exhaust gas temperature is about 140uC higher at 200 s after operation compared with that of gasoline.

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“…The effect of the initial startup position of the piston and valves in the cycle on combustion and HC emissions were examined. The mass of fuel injected, burned and emitted was calculated for each of the first 120 cycles and different approaches to reduce engine-out and tailpipe HC emissions during cold-start were also studied [16]. Tao Li suggests that the partial-heating of the intake port is an efficient and effective method to improve the mixture preparation and combustion of the first cranking cycle during the cold-start stage of port fuel injection engine.…”

Section: Introductionmentioning

confidence: 99%

Research of some operating parameters and the emissions level variation in a spark ignited engine through on-board investigation methods in different loading conditions

Ferenţi

Baldean

2014

Open Engineering

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The present paper shows research made on a spark ignited engine with port fuel injection in different operation conditions in order to improve the comprehension about the cold start sequence, acceleration when changing the gear ratios, quality of combustion process and also any measures to be taken for pollutant reduction in such cases. The engineering endeavor encompasses the pollutants investigation during the operation time of gasoline supplied engine with four inline cylinders in different conditions. The temperature and any other parameters were measured with specific sensors installed on the engine or in the exhaust pipes. All the data collected has been evaluated using electronic investigation systems and highly developed equipment. In this manner it has enabled the outline of the idea of how pollutants of engine vary in different operating conditions. Air quality in the everyday environment is very important for the human health, and thus the ambient air quality has a well-known importance in the European pollution standards and legislation. The high level of attention directed to the pollution problem in the European lifestyle is a driving force for all kinds of studies in the field of the reduction of engine emission.

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Cold-start hydrocarbon emissions in port-injected gasoline engines

Cited by 78 publications

References 88 publications

Flame/Wall Interactions: Laminar Study of Unburnt HC Formation

Flame/Wall Interactions: Laminar Study of Unburnt HC Formation

Combustion characteristics of SI engine fueled with methanol-gasoline blends during cold start

Research of some operating parameters and the emissions level variation in a spark ignited engine through on-board investigation methods in different loading conditions

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