A Study of Efficiency and Emissions for a 4-Stroke SI and a CAI Engine with EEGR and Light Boost

Gaynor, John A.; Fleck, Robert; Kee, Robert J.; Kenny, R. G.; Cathcart, Geoffrey

doi:10.4271/2006-32-0042

Cited by 9 publications

(10 citation statements)

References 22 publications

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“…However, fast heat release and large amounts of fuel at higher engine loads can result with excessive pressure rate rise. According to Gaynor et al [1] and Yap et al [8] application of boost and increase of in cylinder charge mass allows substantial reduction of NO X emission and pressure rate rise simultaneously. In contrast, Scaringe, Wildman an Cheng [4,6] reported that in order to reduce pressure rise rate intake pressure should be minimized.…”

Section: Introductionmentioning

confidence: 99%

Increase of High Load Limit in a Gasoline Hcci Engine

Hunicz¹,

Kordos²,

Gęca³

2015

Journal of KONES. Powertrain and Transport

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Engine operation in HCCI mode allows for improvement of thermal efficiency and substantial reduction NOX emission. The most production feasible solution for gasoline HCCI engine is application of exhaust gas trapping using a negative valve overlap. This technique increases thermal energy of a mixture, thus allowing for auto-ignition at moderate compression ratios. However, high exhaust gas re-circulation rate decreases volumetric efficiency. As a result, achievable engine loads are also reduced. Supercharging can be applied in order to improve volumetric efficiency and extend high load limit. However, increase of amount of intake air can lead to reduction of start of compression temperature via decrease of residuals in a mixture. In order achieve HCCI mode of combustion, temperature of start of compression must be kept within narrow limits. In this study experimental and modeling investigations were presented. Experiments were carried out using single cylinder research engine. The engine was equipped with fully variable valvetrain and direct gasoline injection. Application of mechanical boosting allowed for widening achievable load range in HCCI mode of operation. Numerical calculations allowed for determination of admissible valvetrain settings and intake pressure, which guarantee proper temperature of start of compression.

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Section: Introductionmentioning

confidence: 99%

Increase of High Load Limit in a Gasoline Hcci Engine

Hunicz¹,

Kordos²,

Gęca³

2015

Journal of KONES. Powertrain and Transport

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“…Smaller amount of internally recirculated exhaust can be applied at increased intake pressure without drop of compression temperature. Boost pressure can also be applied in order to control amount of internal exhaust gas recirculation (EGR) without the necessity of valves timings variation [2]. Another limitation of an engine high load limit is engine noise and harshness.…”

Section: Introductionmentioning

confidence: 99%

“…Increase of fuel amount at short combustion duration results in dramatic increase of heat release rate (HRR). According to Gaynor et al [2] and Yap et al [14] application of boost and increase of in cylinder charge mass allows substantial reduction of NO x emission and pressure rate rise (PRR) simultaneously. In contrast, Scaringe, Wildman an Cheng [9,12] reported that in order to reduce PRR intake pressure should be minimized.…”

Section: Introductionmentioning

confidence: 99%

An investigation of supercharged CAI engine with internal gas recirculation and direct gasoline injection

Hunicz¹,

Gęca²

2012

Combustion Engines

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Influence of boost pressure on combustion process and exhaust emission in controlled auto-ignition (CAI) engine was studied. The examinations were carried out using single-cylinder engine with fully variable valvetrain and gasoline direct injection. In order to achieve auto-ignition in-cylinder temperature was elevated with the use of internal gas recirculation (EGR) obtained via the negative valve overlap (NVO) technique. Fuel dilution obtained via increase of intake pressure resulted in substantial reduction of cylinder-out nitrogen oxides emission. However application of boosting resulted in excessive advance of auto-ignition timing and increase of pressure rate rise (PRR) at higher engine loads.

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“…HCCI has been researched for some thirty years. It was first identified by Noguchi et al and Onishi et al as a method to reduce emissions and fuel consumption of two-stroke engines at part-load conditions [7].The main concepts of HCCI are breathing premixed air/fuel mixture, as in conventional spark ignition (SI) engines, and ignition without a spark plug, as in conventional compression ignition (CI) engines [8,9]. In HCCI engine the fuel and air are premixed to form a homogeneous mixture before the compression stroke.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study on the Effects of Egr and Equivalence Ratio on Co and Soot Emissions of Dual Fuel Hcci Engine

Kalateh¹,

Ghazikhani²

2009

Chemical, Biological and Environmental Engineering

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HCCI engines improvements are challenged with high CO emissions. In this study, effects of EGR and equivalence ratio on CO and soot emissions of a dual fuel HCCI engine are investigated. The experiments were conducted on a variable compression ratio(VCR) single-cylinder research engine with compression ratio of 17.5:1. Premixed gasoline is provided by a carburetor connected to intake manifold and equipped with a screw to adjust premixed air-fuel ratio, and diesel fuel is injected directly into the cylinder through an injector at pressure of 250 bars. Intake charge temperature was increased up to 110-115ºC by using an electrical heater. The higher advanced injection timing (35 BTDC) was used to initiate the gasoline auto-ignition in the HCCI dual fuel engine. The results show that increasing EGR rate increases CO emissions due to dilution effect which reduces combustion temperature, also addition of EGR increases soot emission as a result of decreases the inlet air and its oxygen, which create rich points in the cylinder mixture. Results also show that the CO emission decreases by increasing the equivalence ratio due to formation of more OH radicals in the cylinder and increasing the overall reactivity.

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A Study of Efficiency and Emissions for a 4-Stroke SI and a CAI Engine with EEGR and Light Boost

Cited by 9 publications

References 22 publications

Increase of High Load Limit in a Gasoline Hcci Engine

Increase of High Load Limit in a Gasoline Hcci Engine

An investigation of supercharged CAI engine with internal gas recirculation and direct gasoline injection

An Experimental Study on the Effects of Egr and Equivalence Ratio on Co and Soot Emissions of Dual Fuel Hcci Engine

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