Internal Residual vs. Elevated Intake Temperature: How the Method of Charge Preheating Affects the Phasing Limitations of HCCI Combustion

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21220%2F12%3A00229502" target="_blank" >RIV/68407700:21220/12:00229502 - isvavai.cz</a>

Výsledek na webu

<a href="http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1716461&resultClick=1" target="_blank" >http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1716461&resultClick=1</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1115/ICES2012-81127" target="_blank" >10.1115/ICES2012-81127</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Internal Residual vs. Elevated Intake Temperature: How the Method of Charge Preheating Affects the Phasing Limitations of HCCI Combustion

Popis výsledku v původním jazyce

Homogeneous charge compression ignition (HCCI) has the potential to reduce both fuel consumption and NOx emissons compared to normal spark-ignited (SI) combustion. For a relatively low compression ratio engine, high unburned temperatures are needed to initiate HCCI combustion, which is achieved with large amounts of internal residual or by heating the intake charge. The amount of residual in the combustion chamber is controlled by a recompression valve strategy, which relies on negative valve overlap (NVO) to trap residual gases in the cylinder. A single-cylinder research engine with fully-flexible valve actuation is used to explore the limits of HCCI combustion phasing at a constant load of ~3 bar IMEPg. This is done by performing two individual sweeps of a) internal residual fraction (via NVO) and b) intake air temperature to control combustion phasing. It is found that increasing both variables advances the phasing of HCCI combustion, which leads to increased NOx emissions and a higher ringing intensity. On the other hand, a reduction in these variables leads to greater emissions of CO and HC, as well as a decrease in combustion stability. A direct comparison of the two sweeps suggests that the points with elevated intake temperatures are more prone to ringing as combustion is advanced and less prone to instability and misfire as combustion is retarded. This behavior can be explained by compositional differences (air vs. EGR dilution) which lead to variations in burn rate and peak temperature. As a final study, two additional NVO sweeps are performed while holding intake temperature constant at 30°C and 90°C. Again, it is seen that at higher intake temperatures, combustion is more susceptible to ringing at advanced timings and more resistant to instability/misfire at retarded timings.

Název v anglickém jazyce

Internal Residual vs. Elevated Intake Temperature: How the Method of Charge Preheating Affects the Phasing Limitations of HCCI Combustion

Popis výsledku anglicky

Homogeneous charge compression ignition (HCCI) has the potential to reduce both fuel consumption and NOx emissons compared to normal spark-ignited (SI) combustion. For a relatively low compression ratio engine, high unburned temperatures are needed to initiate HCCI combustion, which is achieved with large amounts of internal residual or by heating the intake charge. The amount of residual in the combustion chamber is controlled by a recompression valve strategy, which relies on negative valve overlap (NVO) to trap residual gases in the cylinder. A single-cylinder research engine with fully-flexible valve actuation is used to explore the limits of HCCI combustion phasing at a constant load of ~3 bar IMEPg. This is done by performing two individual sweeps of a) internal residual fraction (via NVO) and b) intake air temperature to control combustion phasing. It is found that increasing both variables advances the phasing of HCCI combustion, which leads to increased NOx emissions and a higher ringing intensity. On the other hand, a reduction in these variables leads to greater emissions of CO and HC, as well as a decrease in combustion stability. A direct comparison of the two sweeps suggests that the points with elevated intake temperatures are more prone to ringing as combustion is advanced and less prone to instability and misfire as combustion is retarded. This behavior can be explained by compositional differences (air vs. EGR dilution) which lead to variations in burn rate and peak temperature. As a final study, two additional NVO sweeps are performed while holding intake temperature constant at 30°C and 90°C. Again, it is seen that at higher intake temperatures, combustion is more susceptible to ringing at advanced timings and more resistant to instability/misfire at retarded timings.

Druh

D - Stať ve sborníku

CEP obor

JT - Pohon, motory a paliva

OECD FORD obor

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Projekt

<a href="/cs/project/ED2.1.00%2F03.0125" target="_blank" >ED2.1.00/03.0125: Pořízení technologie pro Centrum vozidel udržitelné mobility</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2012

Kód důvěrnosti údajů

C - Předmět řešení projektu podléhá obchodnímu tajemství (§ 504 Občanského zákoníku), ale název projektu, cíle projektu a u ukončeného nebo zastaveného projektu zhodnocení výsledku řešení projektu (údaje P03, P04, P15, P19, P29, PN8) dodané do CEP, jsou upraveny tak, aby byly zveřejnitelné.

Název statě ve sborníku

Proceedings of the ASME 2012 Internal Combustion Engine Division Spring Technical Conference ICES2012

ISBN

9780791844663

ISSN

1529-6598

e-ISSN

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Počet stran výsledku

12

Strana od-do

307-318

Název nakladatele

American Society of Mechanical Engineers - ASME

Místo vydání

New York

Místo konání akce

Torino

Datum konání akce

6. 5. 2012

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

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