Detailed chemical kinetic simulations of homogeneous charge compression ignition engine transients

2008 ◽  
Vol 9 (2) ◽  
pp. 149-164 ◽  
Author(s):  
J P Angelos ◽  
M Puignou ◽  
M M Andreae ◽  
W K Cheng ◽  
W H Green ◽  
...  
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Chemical Kinetic ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Detailed Chemical ◽  
Homogeneous Charge

scholarly journals Aqueous solution of ammonia as marine fuel

2020 ◽  
pp. 147509022093715
Author(s):  
Alessandro Schönborn
Keyword(s):  
Aqueous Solution ◽  
Compression Ratio ◽  
Homogeneous Charge Compression Ignition ◽  
Aqueous Ammonia ◽  
Chemical Kinetic ◽  
Diesel Combustion ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Marine Fuel ◽  
Homogeneous Charge

The ignition of ammonia in aqueous solution was simulated in a two-stroke compression ignition engine model. Zero-dimensional chemical kinetic calculations were used to estimate the ignition timing of fuel air mixtures in homogeneous charge compression ignition and diesel combustion modes. The fuel consisted of a 25% m/m aqueous solution of ammonia and pure ammonia for comparison. Ignition was studied by varying the geometric compression ratio of the engine. To ignite ammonia in aqueous solution a minimum compression ratio of 25 was necessary under homogeneous charge compression ignition combustion conditions, whereas under diesel combustion conditions a minimum compression ratio of 27 was required. Ammonia containing ammonium nitrite or hydrogen were two potential ammonia derivatives that were shown to enhance aqueous ammonia ignition in the simulations, and allowed ignition to take place at a compression ratio of 24 for diesel combustion. When comparing the ignition of aqueous ammonia solution to pure ammonia, the minimum compression ratio necessary to ignite pure ammonia was approximately 24.8 and that for aqueous ammonia 26.7 in diesel combustion. This led to the conclusion that aqueous ammonia is not prohibitively more difficult to ignite than pure ammonia. Ammonia containing ammonium nitrite or hydrogen were found to be potential pilot fuels.

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.

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