This content is not included in your SAE MOBILUS subscription, or you are not logged in.
An Onboard Ethanol Concentration Sensor for the Brazilian Market
ISSN: 0148-7191, e-ISSN: 2688-3627
Published October 02, 2012 by SAE International in United States
Annotation ability available
A flex fuel engine is capable of operating efficiently on any combination of gasoline and ethanol. However, an engine combustion strategy must adapt quickly to a change in ethanol concentration after a refueling event in order to achieve optimum engine combustion. Typical control systems rely on an exhaust gas oxygen sensor (lambda) to measure changes in oxygen concentration following combustion. This feedback control approach can take five to ten minutes to detect the fuel change and correct the combustion strategy. This relatively long lag time could result in suboptimal engine performance such as a loss of engine power, engine knocking, poor cold start performance, unburned hydrocarbons, and high pollutant emissions. To counter this shortcoming, an on-board flex fuel sensor (FFS) was developed to enable a feed-forward control strategy. The FFS may be installed inline between the fuel tank and fuel injector and measure the fuel prior to it reaching the injector. The FFS sensor estimates the concentration of ethanol in the fuel in real-time using a correlation based on permittivity, conductivity, and temperature of the fuel flowing through the sensor. The FFS is specifically designed for the Brazilian market and is calibrated to measure the anhydrous ethanol and hydrous ethanol contained in gasohol and alcohol respectively. The sensor can accurately estimate the total ethanol concentration (anhydrous plus hydrous) within +/− five volume percent for any combination of gasohol and alcohol. The sensor can operate with a fuel temperature range of −40°C to 95°C. In addition, the FFS provides diagnostic capability and is able to identify and report water contamination to the engine control module.
CitationMcKay, B., VanVelzen, I., Guth, C., Achleitner, E. et al., "An Onboard Ethanol Concentration Sensor for the Brazilian Market," SAE Technical Paper 2012-36-0249, 2012, https://doi.org/10.4271/2012-36-0249.
- Agência Nacional Do Petróleo, Gás Natural E Biocombustíveis Resolução Anp N° 7 9 2 2011 10 2 2011 14 4 2011 Rio de Janeiro, Brasil
- Theunissen, F. “Percent Ethanol Estimation on Sensorless Multi-Fuel Systems; Advantages and Limitations” SAE Paper No. 2001-01-3562 Warrendale, PA
- Wang, S. Lin, Y. Resendiz, N. Granados, L. Rodriguez, H. “Ethanol Concentration Sensor” SAE Paper No. 2008-01-2452 Warrendale, PA
- Wallner, T. Miers, S. A. “Combustion Behavior of Gasoline and Gasoline/Ethanol Blends in a Modern Direct-Injection 4-Cylinder Engine,” SAE Paper No. 2008-01-0077 2008
- Teulings, W. Zapf, S. Weigl, M. “Identification of Ethanol-based Fuels-blends with - and without an Electrochemical Fuel Sensor,” SENSACT 2007:Sensors and Actuators for Advanced Powertrain Applications Oct. 4 2007
- Rocha, M. S. Simoes-Moreira, J. R. “A Simple Impedance Method for Determining Ethanol and Regular Gasoline Mixtures Mass Content,” FUEL 84 447 2005
- Continental Automotive Group “Flex Fuel Sensor High Integration Generic Specification” 14 APR 2011 Auburn Hills, MI 48326
- Jenkins, C. Mastbergen, D. Standglmaier, R. “Measurement of the Percentage of Biodiesel Blends with a Commercial Dielectric Fuel Sensor” Paper No. ICEF2006-1539. Proceedings of the ASME Internal Combustion Engine Division 2006