Operating Conditions Using Spark Assisted HCCI Combustion During Combustion Mode Transfer to SI in a Multi-Cylinder VCR-HCCI Engine

Hyvönen, Jari; Haraldsson, Göran; Johansson, Bengt

doi:10.4271/2005-01-0109

Cited by 103 publications

(46 citation statements)

References 22 publications

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“…In the HCCI-SI strategy, a rapid and smooth transition process between operation modes is a key factor. Hyvönen et al [20] realized the transition process between the SI and HCCI combustion on a variable compression ratio (VCR) engine with a rapid thermal management system, but misfire was frequently observed during this process. Tian et al [21] also studied the transition process from SI to HCCI modes, during which the valve timing and injection strategy were first changed and the throttle valve position was then adjusted.…”

Section: Introductionmentioning

confidence: 99%

Active fuel design—A way to manage the right fuel for HCCI engines

Huang

Zhang

et al. 2016

Front. Energy

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Homogenous charge compression ignition (HCCI) engines feature high thermal efficiency and ultralow emissions compared to gasoline engines. However, unlike SI engines, HCCI combustion does not have a direct way to trigger the in-cylinder combustion. Therefore, gasoline HCCI combustion is facing challenges in the control of ignition and, combustion, and operational range extension. In this paper, an active fuel design concept was proposed to explore a potential pathway to optimize the HCCI engine combustion and broaden its operational range. The active fuel design concept was realized by real time control of dual-fuel (gasoline and n-heptane) port injection, with exhaust gas recirculation (EGR) rate and intake temperature adjusted. It was found that the cylinderto-cylinder variation in HCCI combustion could be effectively reduced by the optimization in fuel injection proportion, and that the rapid transition process from SI to HCCI could be realized. The active fuel design technology could significantly increase the adaptability of HCCI combustion to increased EGR rate and reduced intake temperature. Active fuel design was shown to broaden the operational HCCI load to 9.3 bar indicated mean effective pressure (IMEP). HCCI operation was used by up to 70% of the SI mode load while reducing fuel consumption and nitrogen oxides emissions. Therefore, the active fuel design technology could manage the right fuel for clean engine combustion, and provide a potential pathway for engine fuel diversification and future engine concept.

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Section: Introductionmentioning

confidence: 99%

Active fuel design—A way to manage the right fuel for HCCI engines

Huang

Zhang

et al. 2016

Front. Energy

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“…Johansson et al [11] in Lund Institute of Technology also investigated the effects of spark ignition on the gasoline SI/HCCI combustion mode transition in a multi-cylinder variable compression ratio HCCI engine. The SI/HCCI combustion mode transition was achieved through adjusting the compression ratio and intake charge temperature.…”

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confidence: 97%

Study the ethanol SI/HCCI combustion mode transition by using the fast thermal management system

et al. 2007

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In this paper the ethanol homogeneous charge compression ignition (HCCI) is achieved in a modified single cylinder engine by means of a self-developed fast thermal management system (FTMS), and the ethanol SI/HCCI operation regions are defined. It can be concluded that the thermal efficiency is higher and the NO x emission is lower in the HCCI operation region. In addition, the maximum NO x emission drops by 98%. The ethanol SI/HCCI combustion mode transition is conducted in different conditions near the SI/HCCI operation boundaries. It is likely to realize the transition by the utilization of FTMS. However, it is impossible to complete the transition within one operating cycle under current operation conditions. There are fluctuations in engine speed and brake mean effective pressure during the transition process. In order to reduce the fluctuations during the transition, the initial work concerning the effects of the spark ignition on the transition smoothness is carried out and the investigation indicates that the engine speed and brake mean effective pressure fluctuations cannot be eradicated only through spark ignition. Therefore, the control strategies combined with other factors should be further optimized.ethanol, homogeneous charge compression ignition (HCCI), combustion mode transition, spark ignition (SI), fast thermal management system (FTMS) With the advantages of high thermal efficiency and extra low NO x and soot emissions, homogeneous charge compression ignition (HCCI) combustion has become a promising combustion method and attracted much attention in internal combustion engine research all over the world since it was put forward in 1970s [1] . However, before putting this new combustion concept into practice, there are still many challenges such as ignition timing control [2] , combustion rate control [3] , limited operation region [4] and relatively high CO and HC emissions [5] , etc.When the engine operates in HCCI combustion mode, the fuel/air mixture is enriched as the engine load increases. By this, the peak in-cylinder temperature will raise, ignition will advance, and combustion rate will accelerate, so combustion phasing is hard to control. Too high combustion rate will result in the occurrence of knocking in the cylinder and this is the HCCI upper boundary. When the engine operates in light load, the peak in-cylinder temperature is a little bit lower, the lean fuel/air mixture is hard to ignite and combust and this is the HCCI lower boundary. In order to fully utilize the HCCI advantages of high thermal efficiency and extra low NO x and soot emission, it is highly recommended that the engine operates in SI with light and heavy load and transits to HCCI in medium load. In doing so, the requirement of the engine power output in heavy load can be satisfied, and the fuel consumption and emission in the medium load can be improved.The engine combustion mode transition concept between SI and HCCI was put forward by Thring [6] in 1989 with the aim of utilizing the high thermal efficiency to ...

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“…misfiring, maximum cylinder pressure, maximum rate of pressure rise, etc., are also included in the control system. Combustion phasing, which is the main control parameter, is calculated as the crank angle of 50% burnt (CA50) and controlled mainly by the inlet air temperature, but also to some extent with cylinder individual air-fuel ratio and spark assistance [11,12,13]. The CA50 is calculated on-line based on a simple heat release analysis.…”

Section: Measurement and Engine Control Systemmentioning

confidence: 99%

“…The original pistons have been changed in the test engine to increase the compression ratio from 9.5:1 to 18:1. The choice of compression ratio is based on the HCCI tests done with the Saab Variable Compression Ratio engine [7][8][9][10][11][12][13][14] and is also about the same as in the truck engine. The engine has a Variable Nozzle Turbine (VNT) turbocharger to control the amount of dilution if needed.…”

Section: The Test Enginesmentioning

confidence: 99%

See 1 more Smart Citation

The Effect of Displacement on Air-Diluted Multi-Cylinder HCCI Engine Performance

Hyvönen¹,

Wilhelmsson²,

Johansson³

2006

SAE Technical Paper Series

Self Cite

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The main benefit of HCCI engines compared to SI engines is improved fuel economy. The drawback is the diluted combustion with a substantially smaller operating range if not some kind of supercharging is used. The reasons for the higher brake efficiency in HCCI engines can be summarized in lower pumping losses and higher thermodynamic efficiency, due to higher compression ratio and higher ratio of specific heats if air is used as dilution. In the low load operating range, where HCCI today is mainly used, other parameters as friction losses, and cooling losses have a large impact on the achieved brake efficiency.To initiate the auto ignition of the in-cylinder charge a certain temperature and pressure have to be reached for a specific fuel. In an engine with high in-cylinder cooling losses the initial charge temperature before compression has to be higher than on an engine with less heat transfer. The heat transfer to the combustion chamber walls is affected by parameters such as area-to-volume ratio and in-cylinder gas motion, i.e. turbulence.In this paper the performance of three multi-cylinder HCCI engines with different displacements are compared. The engines are a five-cylinder 1.6dm 3 VCR engine, a four-cylinder 2.0dm 3 engine, and a six-cylinder 11.7dm 3 truck engine. All engines are port fuel injected and run with a RON91/MON82 gasoline. Combustion phasing is mainly controlled with inlet air temperature. The engines have about the same indicated efficiency but different brake efficiency. The truck engine has 32.3% brake efficiency at 2bar BMEP, followed by the 2.0dm 3 engine with 29.8%, and the 1.6dm 3 VCR engine with only 24.4%.

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Operating Conditions Using Spark Assisted HCCI Combustion During Combustion Mode Transfer to SI in a Multi-Cylinder VCR-HCCI Engine

Cited by 103 publications

References 22 publications

Active fuel design—A way to manage the right fuel for HCCI engines

Active fuel design—A way to manage the right fuel for HCCI engines

Study the ethanol SI/HCCI combustion mode transition by using the fast thermal management system

The Effect of Displacement on Air-Diluted Multi-Cylinder HCCI Engine Performance

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