[Wbo2] Bosch LSU4 with the DIY-WB

[allen brown]

Blah,blah,blah, what a whiner. I have to get a new keyboard as I puked all over it reading this drivel.
 
Al.


Peter Gargano <peter at techedge.com.au> wrote:
allen brown wrote:
> Considering the source not a surprising response. The
> Bosch sensor has been made to work with the DIY-WB
> design years ago.

One of the first things we (Tech Edge) did when we decided the L1H1 
was way overpriced was to connect the LSU up in much the same DIY-WB 
circuit as the NTK. Sure, we got it to work, and it gave some sort of 
readings that we could have worked out a new Vout Vs. AFR table for. 
But I couldn't see the point of people spending time and money 
building something that was going to give just an "indication of AFR" 
- I mean, that's just what a zero-extra-cost narrowband sensor will do 
for you - or, for a little more accuracy, a fairly expensive NTK 
sensor and an inexpensive DIY-WB circuit.

At the time the NTK sensor jumped in price, I decided Tech Edge had 
come to a junction, so I asked the question : do we drop DIY-WB, or 
make AFR sensing a "proper" business? So, finding some local people 
who had a similar interest, I put a lot of development dollars into 
producing a professional quality microprocessor controlled WB unit 
primarily for the LSU. And shortly after we released that unit, we 
made it available as a DIY kit. We have sold thousands of these 
version 2A0 kits (as kits, and many more as "prebuilt" units). I have 
published the schematics for the 2A0 design, (but we retain the 
unpublished firmware) and it is a very popular device. But ...

It's important to realise that the Bosch LSU is designed to be 
different to the Honda-NTK UEGO device. It really needs to be 
controlled better to give similar results to the NTK. But, if it's 
controlled properly, it has the potential to be more accurate than the 
NTK.

> IIRC (it's in the archives) the
> gentleman that did this lowered the heater voltage and
> it worked. He was in Greece (help for a search).

In early 2003 I was in contact with the "Greek guy" (Giannoulis 
Kafetzis) that did this, and provided him with a little information to 
get him going. I can provide an email address if it's not readily 
available in the archives.

> Also, why not a junkyard sensor? For the price it is
> well worth trying out. Absolute accuracy isn't always
> a requirement. Much tuning can be accomplished with a
> WB.

Sure, if you can get a junkyard part for a few tens of dollars, but if 
we're talking around the $100 mark then I can't see that the 
cost/benefit ratio is good. I'd stick with the NB sensor or go with a 
field proven low cost design with a low cost sensor. But if you want 
to go NTK ...

I'd suggest that Steve Nichols (see previous email from Jurgen) is the 
person to get the sensor from if you really want to use the "old" 
circuit. I believe he sells them for US$120. (we sell a connector kit 
for AU$9 that mates to it).

Final point: I'm not writing this in order to drum up sales, but to 
provide an alternative view point on the cost benefit ratio of the 
original DIY-WB design.

And, to those who, after all these years, think I did something wrong 
in making the original OZ-DIY-WB design readily available, and at a 
small cost - please don't put that forward as an argument to otherwise 
unbiased people who couldn't give a damn, and are just after honest 
accurate advice on how to get a low cost WB instrument.


Peter.

PS. I don't intend to get into any discussions that are otherwise 
ancient history, but I will respond to technical questions about using 
the LSU sensor.









te.
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