Bosch LSM11 Resistance (Ri) Curve Data? (was RE: DIY_EFI Digest V5 #595)

[Glenn & Debbie Woodhouse]

Thanks for the reply Eric.  I too saw this post a couple of months ago when
surfing the archives.  I tried to locate Mike Licht and Modern Muscle in
Detroit with no luck.  I have a scanned Bosch data sheet from the archives
but it only provides me with A/F ratio to voltage and temperature (in the
rich range).  I could have easily missed something in the archives though.
If you find anything it would be appreciated.

Does anyone know if Frank Parker is still at the fparker at umich.edu address??
I haven't seen him posting in recent times.  I'll give that address a whirl.

Glenn.

------------------------------

Date: Mon, 30 Apr 2001 07:56:29 -0400
From: Eric Fahlgren <efahl at adams.com>
Subject: Re: DIY_EFI Digest V5 #591

Glenn & Debbie Woodhouse wrote:
>
> Eric,
>
> I have dug through the archives and found the Bosch LSM11 curves that
relate
> A/F ratio to voltage and temperature (in the rich range) but I have not
seen
> the curves for probe resistance vs. temperature, which is the key to using
> this sensor as a wide band meter without incorporating an EGT into the
> system.  If you have this data or know where to get it I would be very
> interested.

Glenn,

A quick scan of the '96 archives gives me this in a post from
Frank Parker <fparker at umich.edu> dated 27 Nov 1996:

> BUT there appears to be another solution- the Bosch LSM-11 sensor as used
> in their LA-2 $5000 air fuel meter. The sensor alone is about $190. I just
> purchased 3 more at that price from a Bosch distributor. I have the cal
> tables on this sensor and I also gave copy to Jim. We started to design
> an interface for this sensor as it is much simpler. This sensor has the
> BIG ADVANTAGE that its voltage curve is a very close match to a std sensor
> as thus you can just replace the std sensor in your car with the LSM-11
> and then car will run fine on it. Then can hook up your a/f interface box
> in parallal and read out a/f ratio. The main thing to solve with this
sensor
> is the large temperature correction. The idea was to use a PIC as a
> controller. Figure out a math function ( 3rd order or so) to match the
> std S shaped curve, then use the temp as an offset function in the
> controller. The internal resistance of the sensor changes from about
> 10 ohms to over 100 ohms and is a indication of the temperature.
> To give you an idea of the shift with temp, note the following:
>           OUTPUT      650 deg       750 deg        900  deg
> 	830 mv	      13.94        13.23           12.02
> As you can see if you are tuning for max power, there is a big difference
> between 13.9 and 12.0 air/fuel at a fixed 0.83 volts.
> All is not lost, Mike Licht @ Modern Muscle here in Detroit(810-754-0261)
> is in final test stages of a a/f meter that uses this sensor. Will sell
> for $800 including the sensor. That is why Jim and I stopped work on our
> design and are waiting for the MM meter. Interested parties can call
> Mike @ above #

I seem to remember seeing a post in the '96 or '97 archives where
someone had scanned and posted the actual Bosch datasheets.  If I
find that I'll let you know.

Eric
- --
Eric Fahlgren                            Mechanical Dynamics, Inc
efahl at adams.com                          Ann Arbor, Michigan, USA
- --------------------------------------------------------------------------
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