flex fuel sensors

[bkibbe]

Where can I find info on how flex fuel sensors work?
thanks

 

[Ron07663]

Not sure how detailed or technical an explanation you need, but this web site has a general overview of the sensor operation:

http://www.megamanual.com/flexfuel.htm

 

[WGJ]

I couldn't say about 'modern' sensors (per the MegaSquirt site) but, some years back, AC Rochester (now part of Delphi) marketed a flex-fuel/alcohol sensor which worked on the capacitive principle, using the fuel as the dielectric and refering the capacitance measured to some table of alcohol/gasoline blend values.
Might be worth trawling around

http://www using

that.

 

[Fabrico]

Capacitive fuel level sensors are used extensively on military aircraft.

 

[WGJ]

Yes --- Level Sensors, however, I think the original question was aimed at sensing the gasoline/alcohol blend percentages in a fuel, rather than the level of fuel in a tank.
There must be modern sensor technology for support of 'flexfuel' and E85 vehicles.

This site refering to flexfuel in Brazil is interesting:

http://www.italiaspeed.com/2006/car...tti_marelli_challenge_bibendum/flex_fuel.html

Magneti Marelli refer to their method as SFS (Software Flexfuel Sensor). A quick read suggests that exhaust gas oxygen (per the EGO/HEGO/Lambda sensor) is primarily used to set the fueling where varying levels of alcohols are encountered, rather than trying to work out what's in the feed fuel. Maybe they are using wideband/universal EGO sensors.

 

[trevorrus]

Software based systems for flex-fuel vehicles (vehicles able to operate on alcohol / gasoline blends with greater than 10% alcohol) do indeed use O2 sensor feedback. Several systems are available using binary sensors as well as wideband O2 sensors. Binary systems evaluate the required fuelling correction to achieve stoichiometric operation and infer the shift in stoichiometry from this, the assumption being that the fuelling correction is entirely attributed to a change in fuel composition. Wideband sensor based systems use a combination of the shift in fuelling correction and the AFR response to load transients to calculate the % alcohol present in the tank.

 

[TDLin]

Siemens supplied a capacitance based flex fuel sensor to GM up until a couple years ago. They are likely to be continuing its production for some European or other customers. Involved 2 electrode cells in casting with glass to metal seals. As noted earlier, the electronics measured dielectric constant of fuel mixture flowing through defined plate area. You might attempt to contact them.

 

[Darren3]

See this webpage for some details of one type of sensor

http://www.energy.state.md.us/programs/transportation/biodiesel/presentations/van_gerpen.pdf

 

[pasmetrique]

Hello,

you can find out more here:

http://www.sae.org/technical/papers/910498

Measurement of refractive index technology is used for new FCS (fuel composition sensors)