charlie_pank Posted April 5, 2005 Share Posted April 5, 2005 I know that these things are basically "on" or "off" so no good for giving accurate readings, but what I want to do is gather a large amount of data in order to use an average reading for each point in the emerald injection map to determine whether the engine is running rich or lean at each point. I've written the parser to do this working off the excel output from the emerald software, but what I need to know, is what is the ideal mV reading I should be looking for? - I'm thinking about 0.3 for low load sites and .65 for high load ones - anyone got any views on this? (Currently running with most of them averaging above .8) Edited by - charlie_pank on 5 Apr 2005 12:03:18 Link to comment Share on other sites More sharing options...
Myles Posted April 5, 2005 Share Posted April 5, 2005 mV - milivolts? We normally talk in terms of AFR don't we? Project Scope-Creep is underway... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
charlie_pank Posted April 5, 2005 Author Share Posted April 5, 2005 sorry, you've lost me already! Link to comment Share on other sites More sharing options...
Bob Corb Posted April 5, 2005 Share Posted April 5, 2005 Volts, typically ranges from 0.8V (Rich) to 0.3V (lean) but is very sensitive around stoichiometric. I doubt you'l be able to get it to set at 0.65V for very long. Try and borrow an Innovate box which has a comparatively linear measurement range / voltage output which you can use to determine how rich/lean you want to run and also enable your PID control to stand a chance of working. Also you might not need to run lambda = 1 or stoichiometric of you dont have a cat, you could run slightly lean and save a bit of fuel consumption although you need to get your transient fuelling spot on if you intend to do this. Most aftermarket maps (and even std ones from some small car manufacturers) run rich almost evrywhere in order to prevent misfires during transients. Link to comment Share on other sites More sharing options...
Myles Posted April 5, 2005 Share Posted April 5, 2005 AFR - Air Fuel Ratio. My Emerald is currently set to display the lambda readings in these terms - the AFR=14.6 when lambda = 1 IIRC (and anything of AFR>14.6 is lean, anything less is rich) - I'd assume that the datalog also records it in these terms if set correctly. Project Scope-Creep is underway... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
charlie_pank Posted April 5, 2005 Author Share Posted April 5, 2005 The only info the lambda probe provides is mV, so I guess I could rephrase the question to ask what factor do you use to convert mV to AFR, and then what AFR should I aim for during light load and what AFR should I aim for during power loads? BTW - I don't need to get it to SIT at .65, what I'm aiming for is an average reading of .65 over many samplings. Edited by - charlie_pank on 5 Apr 2005 13:07:51 Link to comment Share on other sites More sharing options...
Bob Corb Posted April 5, 2005 Share Posted April 5, 2005 It's a non linear sensor so it will read so it will read around 0.3V whenever its rich of stoich and 0.8v when lean. When the AFR goes past 14.6 there is almost a step change in output. It won tell you how lean or how rich with any real accuracy, sorry. Normal car EMS uses a type strategy to nudge the fueling richer and richer until it sees the output shift and then it starts nudging the other way. If you plot fueling vs time at steady state it looks liek a sawtooth pattern. Link to comment Share on other sites More sharing options...
charlie_pank Posted April 5, 2005 Author Share Posted April 5, 2005 Bob, it looks like it's the other way round (ie .8mv = rich not lean) Link to comment Share on other sites More sharing options...
Bob Corb Posted April 5, 2005 Share Posted April 5, 2005 Oops, I got my Bosch book out and everyfink, I always get it mixed up. I must have been looked at equivalence ratio (1/lambda). But it is volts not mV. Adam Mann did something similar to you using a LSU lambda sensor and a bit of datalogging software and then used it to log AFR whilst he drove. With the MBE 967 (R300 etc) I think you can patch an Etas LA3 (box which reads wide band lambda sensors) into the ECU and switch on the adaptive mapping to get a target AFR vs speed and load. I've been meaning to give it a try for ages. If I ever get my car working I'm going to give it a try. BC Edited by - Bob Corb on 5 Apr 2005 22:24:18 Link to comment Share on other sites More sharing options...
Lawrence_Z Posted April 5, 2005 Share Posted April 5, 2005 Charlie Why not try borrowing one of Bill's original wide band lambda's from you local AO Lawrence Link to comment Share on other sites More sharing options...
Tom White Posted April 6, 2005 Share Posted April 6, 2005 If you want an idea of what the Lambda output looks like on an Oscilloscope, I measured mine here (you will have to scroll down a bit to find it) you will see that the output varies between about 0.1V (100mV) and 0.8V and cycles at about 150mS. Tom Link to comment Share on other sites More sharing options...
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