Case 14284

Detection of Ethanol Emission From a Spark Ignition Engine Operating on Gasohols


Ethanol emission, mass spectrometry, gasohol

  • Ethanol emission detection instrument to be used by car manufacturers, research laboratories and emission certification laboratories.
  • Apply to existing mass spectrometers using software based on this new method.
  • Ethanol gas detection in refinery and other process plants where ethanol gas is present.


Interference between gas species limits the accuracy of ethanol measurement by existing photo-acoustic sensors in car exhaust gas. Conventional detection using sampling and HPLC requires lengthy analysis time.


The purpose of this invention is to detect and quantify the ethanol concentration in exhaust gas using mass spectrometry. Ethanol measurement from flexfuel vehicles is required in order to meet the US Environmental Protection Agency and California Air Resources Board regulations. Most car manufacturers use the photoacoustic sensor, which is subject to interference from other gas species in the exhaust gas. Careful calibration has to be performed in order to remove this interference. This proposed technology will eliminate the interference problem by detecting mass number 31 in the mass spectrum of the exhaust species, which measures the ethanol concentration selectively in the presence of other exhaust gas species.

  • Accurate and rapid ethanol detection free of interference.

  • Professor Wai K. Cheng (Department of Mechanical Engineering, MIT)
  • PKenneth Kar (Department of Mechanical Engineering, MIT)

Intellectual Property:

US Patent Application 12/901029 filed on Oct 8, 2010


Kar, K. and Cheng, W.K. (2011) Using Mass Spectrometry to Detect Ethanol and Acetaldehyde Emissions from a Direct Injection Spark Ignition Engine Operating on Ethanol/Gasoline Blends. SAE Technical Paper No. 2011-01-1159. SAE World Congress 2011, Detroit, April 12-14. DOI: 10.4271/2011-01-1159.

Last revised: June 2, 2011

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