Characterizing the cyclic variability of ignition timing in a homogeneous charge compression ignition engine fuelled with n-heptane/iso-octane blend fuels

2008 ◽  
Vol 9 (5) ◽  
pp. 361-397 ◽  
Author(s):  
M Shahbakhti ◽  
C R Koch
Keyword(s):  
Equivalence Ratio ◽  
Homogeneous Charge Compression Ignition ◽  
Coolant Temperature ◽  
Cyclic Variation ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Compression Ignition Engine ◽  
Hcci Combustion ◽  
Cyclic Variations ◽  
Homogeneous Charge

The cyclic variations of homogeneous charge compression ignition (HCCI) ignition timing is studied for a range of charge properties by varying the equivalence ratio, intake temperature, intake pressure, exhaust gas recirculation (EGR) rate, engine speed, and coolant temperature. Characterization of cyclic variations of ignition timing in HCCI at over 430 operating points on two single-cylinder engines for five different blends of primary reference fuel (PRF), (iso-octane and n-heptane) is performed. Three distinct patterns of cyclic variation for the start of combustion (SOC), combustion peak pressure ( Pmax), and indicated mean effective pressure (i.m.e.p.) are observed. These patterns are normal cyclic variations, periodic cyclic variations, and cyclic variations with weak/misfired ignitions. Results also show that the position of SOC plays an important role in cyclic variations of HCCI combustion with less variation observed when SOC occurs immediately after top dead centre (TDC). Higher levels of cyclic variations are observed in the main (second) stage of HCCI combustion compared with that of the first stage for the PRF fuels studied. The sensitivity of SOC to different charge properties varies. Cyclic variation of SOC increases with an increase in the EGR rate, but it decreases with an increase in equivalence ratio, intake temperature, and coolant temperature.

Residual-effected homogeneous charge compression ignition at a low compression ratio using exhaust reinduction

2003 ◽  
Vol 4 (3) ◽  
pp. 163-177 ◽  
Author(s):  
P. A. Caton ◽  
A. J. Simon ◽  
J. C. Gerdes ◽  
C. F. Edwards
Keyword(s):  
Compression Ratio ◽  
Equivalence Ratio ◽  
Homogeneous Charge Compression Ignition ◽  
Compression Ignition ◽  
Single Digit ◽  
Hcci Combustion ◽  
Actuation System ◽  
Order Of Magnitude ◽  
No Emissions ◽  
Homogeneous Charge

Studies have been conducted to assess the performance of homogeneous charge compression ignition (HCCI) combustion initiated by exhaust reinduction from the previous engine cycle. Reinduction is achieved using a fully flexible electrohydraulic variable-valve actuation system. In this way, HCCI is implemented at low compression ratio without throttling the intake or exhaust, and without preheating the intake charge. By using late exhaust valve closing and late intake valve opening strategies, steady HCCI combustion was achieved over a range of engine conditions. By varying the timing of both valve events, control can be exerted over both work output (load) and combustion phasing. In comparison with throttled spark ignition (SI) operation on the same engine, HCCI achieved 25–55 per cent of the peak SI indicated work, and did so at uniformly higher thermal efficiency. This was accompanied by a two order of magnitude reduction in NO emissions. In fact, single-digit (ppm) NO emissions were realized under many load conditions. In contrast, hydrocarbon emissions proved to be significantly higher in HCCI combustion under almost all conditions. Varying the equivalence ratio showed a wider equivalence ratio tolerance at low loads for HCCI.

Experimental Investigation of Homogeneous Charge Compression Ignition Engine of Ethanol and Diesel Blends

2013 ◽  
Vol 440 ◽  
pp. 254-259 ◽  
Author(s):  
S. Natarajan ◽  
N.V. Mahalakshmi ◽  
S. Sundarraj
Keyword(s):  
Experimental Investigation ◽  
Homogeneous Charge Compression Ignition ◽  
Fuel Injection ◽  
Research Work ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Ignition Timing ◽  
Compression Ignition Engine ◽  
Reduction Of Oxides ◽  
Homogeneous Charge

This paper deals with the experimental investigation of a Homogeneous Charge Compression Ignition (HCCI) Engine system. The main objective of this research work is to study the effects of a premixed fuel ratio on the performance, combustion characteristics and reduction of oxides of nitrogen and smoke intensity, using the HCCI concept. The engine used for the experiments was of a Kirloskar TAF-I series. The engine is a four stroke, single cylinder air cooled diesel engine, of a rated power of 4.4 kW loaded with an electrical dynamometer. An electronic fuel injection circuit was developed to control the ignition timing and duration of the premixed charge. Ethanol was premixed, and a part injected before ignition, whereas the diesel fuel was injected by the conventional injector directly into the cylinder. The part injected ethanol and direct injected diesel were tested in various proportions, to optimize the operating range, and the same setup was tested with various % of EGR.The obtained results include data plots illustrating the performance, combustion and emission characteristics. The results indicate that the concentration of the oxides of nitrogen species rapidly decreased, and the smoke emissions were reduced simultaneously at 20% Rp and 20% EGR in 75% load and full load conditions.

A Spectroscopic Analysis of Combustion in Homogeneous Charge Compression Ignition Engine

2007 ◽  
Author(s):  
Akira Iijima ◽  
Hideo Shoji
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Light Emission ◽  
Emission Spectra ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Strong Light ◽  
Fuel Ratio ◽  
Hcci Combustion ◽  
Ignition And Combustion ◽  
Homogeneous Charge

The principal issues of Homogeneous Charge Compression Ignition (HCCI) combustion that must be addressed include ignition timing control and expansion of the stable operation region. Detailed analyses of ignition and combustion mechanisms must be undertaken to resolve these issues. In this study, spectroscopic technique was used to investigate the effects of the air-fuel ratio (AFR) and residual gas state on ignition and combustion characteristics. Spectroscopic measurement was made of light emission spectra. The results revealed that the distribution profile of the light emission intensity of the hot flame differed substantially depending on the air-fuel ratio (AFR). In high AFR condition, a continuous spectrum attributed to carbon monoxide-oxygen (CO-O) glow is seen between 300–500 nm, but there is no strong light emission such as that from the OH radical. However, decreasing the AFR, a strong light emission is seen a little after the CO-O glow in a wavelength range from visible light to the near-infrared region (500–850 nm). It is also clear that increasing the internal EGR declined the cool flame magnitude, which substantially altered the ignition characteristics of HCCI combustion. Specifically, when a low-octane fuel was used, the heat release rate waveform for HCCI combustion showed two-stage ignition, which was clearly observed in the light emission spectra.

scholarly journals The research and analysis of Homogeneous Charge Compression Ignition Engine

2021 ◽  
Vol 2125 (1) ◽  
pp. 012016
Author(s):  
Binzhi Sun ◽  
Hexu Wang ◽  
Keming Yan ◽  
Renyi Zhang
Keyword(s):  
Mass Production ◽  
Homogeneous Charge Compression Ignition ◽  
Fuel Efficiency ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Compression Ignition Engine ◽  
Gasoline Engines ◽  
Combustion Technology ◽  
Homogeneous Charge

Abstract HCCI represents homogeneous charge compression ignition. It is a cleaner, higher thermal efficiency, and higher fuel efficiency alternative combustion technology. This engine combines the advantages of diesel and gasoline engines so that the compression ratio of diesel engines can be achieved even when gasoline is used as fuel, and there is basically no NOx and soot emissions. However, the HCCI still has some problems such as ignition timing unstable, bad load and speed variation, and cold start capacity. Today, due to the above shortcomings, HCCI is still mainly researched and developed in the laboratory without mass production. The purpose of this paper is discussing the advantage and disadvantage of HCCI technique and analyse the operating principle to provide possible solution that will improve the quality of HCCI engine before the mass production of HCCI.

A Stand-Alone Multi-Zone Model for Combustion in HCCI Engines

2005 ◽  
Author(s):  
Paitoon Kongsereeparp ◽  
Behzad Kashani ◽  
M. David Checkel
Keyword(s):  
Equivalence Ratio ◽  
Homogeneous Charge Compression Ignition ◽  
Residual Fraction ◽  
Zone Model ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Operating Variables ◽  
Hcci Combustion ◽  
Combustion Duration ◽  
Hcci Engines

Because they have the potential for ultra low NOx emissions and high efficiency, Homogeneous Charge Compression Ignition (HCCI) engines have the potential to develop a significant niche. However, a narrow operating range, (bracketed by severe knock and misfire problems), presents a formidable obstacle to developing usable HCCI combustion systems. HCCI combustion is influenced by a complex array of operating variables including fuel octane quality, intake preheating temperature, compression ratio, equivalence ratio, exhaust gas recirculation and engine component temperature. These variables affect the two critical combustion parameters: ignition timing and combustion duration. If these two parameters can be controlled by appropriate settings of the operating variables, a good HCCI combustion scheme could be achieved. Therefore, the theoretical prediction of these two combustion parameters as a function of the key operating variables is necessary for development of HCCI combustion. This paper describes a stand-alone, single-zone and multi-zone combustion model which have been developed for the specific purpose of investigating HCCI combustion control. In the multi-zone model, temperature and composition in each zone were adjusted in order to study the effect of in-homogeneity which is critical to understanding ignition timing and combustion duration in real HCCI engines. The models simulated HCCI combustion using two fuels: hydrogen, (11 species, 23 reactions- from CHEMKIN library), and natural gas, (53 species, 325 reactions- from GRI mech). The capabilities of the two models to predict ignition timing, combustion duration and peak pressure were verified against experimental and simulation results of Fiveland et al [2, 11]. The models were then used to study the effect of different in-homogeneity levels of equivalence ratio, intake temperature and residual fraction. The single zone model could only predict ignition timing while the multi-zone model shows the capability to mimic realistic HCCI combustion phenomena. The study showed that some degree of in-homogeneity is critical to predicting performance of the homogeneous charge compression ignition engine. Further, stratification of equivalence ratio was relatively ineffective at changing combustion while stratification of mixture temperature was very effective. Stratification of the residual fraction proved to be the most promising method of controlling combustion parameters and the mechanism was primarily thermal.

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