Ion sensors have been shown to be a low-cost and robust method of measuring start of combustion (SOC) in Homogeneous Charge Compression Ignition (HCCI) engines. The combustion event in an HCCI engine is governed by temperature sensitive chemical-kinetics and is highly fuel dependent. Autoignition variability between various fuels can also affect emissions, efficiency, and overall operating range of the HCCI engine. Ion sensors (i.e. modified spark-plugs) can be used pragmatically to detect the combustion event for various fuels in HCCI engines over a wide range of operating conditions. An investigation of the ion currents produced from the combustion of gasoline, ethanol, and n-heptane in a 1.9L 4-cylinder VW TDI diesel engine (converted to run in HCCI mode) is conducted over a range of equivalence ratios, intake temperatures, and intake pressures. Gasoline, ethanol and n-heptane have diverse autoignition characteristics which affect the overall operation of the HCCI engine. Experiments show that detecting ions during combustion is a sufficient and reliable technique used in measuring SOC for various fuels in a HCCI engine. The ion currents for gasoline and ethanol are comparable, while n-heptane produces a much weaker ion current. The fact that gasoline and ethanol have comparable ion currents has huge implications in regards to the use of fuel blends consisting of 85% ethanol and 15% gasoline (E85) in HCCI engines. Additionally, the ability to measure ion currents using n-heptane fuel suggests ions may be measurable in diesel fueled HCCI engines.
Homogeneous Charge Compression Ignition (HCCI) Engine
Sae Int. J. Fuels Lubr
Sae International Journal of Fuels and Lubricants
Powertrains, Fuels and Lubricants Meeting ; 2009
Sae International Journal of Fuels and Lubricants ; 2 , 1 ; 817-826
2009-06-15
10 pages
Conference paper
English
Homogeneous charge compression ignition ( HCCI ) engine
Automotive engineering | 2009
|Homogeneous-Charge Compression-Ignition (HCCI) Engines
SAE Technical Papers | 1989
|Homogeneous-charge compression-ignition ( HCCI ) engines
Automotive engineering | 1989
|Axial fuel stratification of homogeneous charge compression ignition ( HCCI ) engine
Automotive engineering | 2007
|