Homogeneous Charge Compression Ignition (HCCI) Using Isooctane, Ethanol and Natural Gas - A Comparison with Spark Ignition Operation 972874
The Homogeneous Charge Compression Ignition (HCCI) is the third alternative for combustion in the Internal Combustion (IC) engines. Here, a homogeneous charge is used as in a spark ignited engine but the charge is compressed to auto-ignition as in a diesel. The characteristics of HCCI were compared to SI using a 1.6 liter single cylinder engine with compression ratio 21:1 in HCCI mode and 12:1 in SI mode. Three different fuels were used; isooctane, ethanol and natural gas.
Some remarkable results were noted in the experiments: The indicated efficiency of HCCI was much better than for SI operation. Very little NOx was generated with HCCI, eliminating the need for a LeanNOx catalyst. However, HCCI generated more HC and CO than SI operation. Stable and efficient operation with HCCI could be obtained with λ=3 to λ=9 using isooctane or ethanol. Natural gas, with a higher octane number, required a richer mixture to run in HCCI mode.
Citation: Christensen, M., Johansson, B., and Einewall, P., "Homogeneous Charge Compression Ignition (HCCI) Using Isooctane, Ethanol and Natural Gas - A Comparison with Spark Ignition Operation," SAE Technical Paper 972874, 1997, https://doi.org/10.4271/972874. Download Citation
Magnus Christensen, Bengt Johansson, Patrik Einewall
Lund Institute of Technology
International Fuels & Lubricants Meeting & Exposition
SAE 1997 Transactions - Journal of Fuels and Lubricants-V106-4