Berg, I must confess, I don't get your point. What are you asking me to say about 14 - 15 to 1 AFR for diesel engines, i.e stoichiometric combustion? If you don't think it can be done then you better tell the John Deere Company that. Their John Deere model 6090 diesel engine runs with stoichiometric combustion. I'm sure a John Deere representative would be more than happy to explain their product to you. Let me be specific on this next point. Go to this link which I already suggested:http://franzh.home.texas.net/lean.html
You'll have to use the scroll function on this site but it was an article put out by a Mr. Franz Hoffman. Mr. Hoffman's credentials as an expert on diesel engine technology is impressive, at least to me. And if you have any question regarding his article he is available online and may answer your questions. Possibly for a fee however. Please note, so don't ask, I will not answer for Mr. Hoffman on anything in his article, for his expertise, I admit, is greater than mine. I only have an academic interest in the subject. Moving along, go to the link and scroll down to the graph under the Diesel Engine
portion of the article. Now look at the concentrations of O2, CO2 and CO for the various values of lamba (where a lamba of 1 = stoichiometric mixture). Now, go to any authoritative source on the toxicity of these molecules and look up the lethal concentrations for these molecules. Go back to the graph and please tell me, or maybe Grenadier can chime in, where on that graph, i.e, for what lamba value, will a person not be killed? I can't make it any simpler and easier than that.