Miniature free-piston homogeneous charge compression ignition engine-compressor concept—Part II: modeling HCCI combustion in small scales with detailed homogeneous gas phase chemical kinetics

2002 ◽  
Vol 57 (19) ◽  
pp. 4173-4186 ◽  
Author(s):  
H. T. Aichlmayr ◽  
D. B. Kittelson ◽  
M. R. Zachariah
Keyword(s):  
Gas Phase ◽  
Chemical Kinetics ◽  
Homogeneous Charge Compression Ignition ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Free Piston ◽  
Hcci Combustion ◽  
Small Scales ◽  
Engine Compressor ◽  
Phase Chemical

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.

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.

Time-resolved IR chemiluminescence in gas-phase chemical kinetics

1999 ◽  
Vol 68 (3) ◽  
pp. 171-181 ◽  
Author(s):  
Evgenii N Chesnokov ◽  
Viktor N Panfilov
Keyword(s):  
Gas Phase ◽  
Chemical Kinetics ◽  
Time Resolved ◽  
Phase Chemical

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.

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