Numerical Investigation of Homogeneous Charge Compression Ignition (HCCI) Combustion with Detailed Chemical Kinetics Using On-the-Fly Reduction

2011 ◽  
Vol 25 (8) ◽  
pp. 3369-3376 ◽  
Author(s):  
Kaiyuan He ◽  
Ioannis P. Androulakis ◽  
Marianthi G. Ierapetritou
Keyword(s):  
Numerical Investigation ◽  
Chemical Kinetics ◽  
Homogeneous Charge Compression Ignition ◽  
Compression Ignition ◽  
Detailed Chemical Kinetics ◽  
Hcci Combustion ◽  
Detailed Chemical ◽  
Homogeneous Charge

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.

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.

Active valvetrain for homogeneous charge compression ignition

2005 ◽  
Vol 6 (4) ◽  
pp. 377-397 ◽  
Author(s):  
N Milovanovic ◽  
J G W Turner ◽  
S A Kenchington ◽  
G Pitcher ◽  
D W Blundell
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Cold Start ◽  
Smooth Transition ◽  
Engine Management System ◽  
Compression Ignition ◽  
Load Range ◽  
Hcci Combustion ◽  
Particulate Matter Emissions ◽  
Mode Transitions ◽  
Homogeneous Charge

Homogeneous charge compression ignition (HCCI), also known as controlled autoignition (CAI) or the premixed charge compression ignition (PCCI) engine concept, has the potential to be highly efficient and to produce low NOx, carbon dioxide, and particulate matter emissions. However, it experiences problems with cold start in a gasoline HCCI engine, running at idle and at high loads, which, together with controlling the combustion over the entire speed/load range, limits its practical application. A way to overcome these problems is to operate the engine in ‘hybrid mode’, where the engine operates in HCCI mode at low, medium, and cruising loads and can switch to or from spark ignition (SI) or diesel (CI) mode for a cold start, idle, and higher loads. Such an engine will have frequent changes in engine load and speeds and therefore frequent transitions between HCCI and SI combustion modes. The valvetrain and engine management system (EMS) have to provide a successful control of HCCI mode and a fast and smooth transition keeping all relevant engine parameters within an acceptable range. Consequently, this leads to high demands on the valvetrain and therefore a need for a very high degree of flexibility. The aim of this paper is to present the potential of a fully variable valvetrain (FVVT) system, the Lotus active valvetrain (AVT™), for controlling HCCI combustion and enabling fast and smooth mode transitions in a HCCI/SI engine fuelled with commercially available gasoline (95 RON) and in a HCCI/DI engine fuelled with diesel (50 CN) fuel.

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