I know your an emissions inspector, and I was wondering if you had any good sources of information about ICE emissions? I have to do a presentation this week for a class and could use the help you(or anyone else) could give me. Thanks.
I have to give a report about minimizing emissions by whatever means possible. I'm on the Michigan Tech clean snowmobile team. Basically, we have a Honda CBR 954 streetbike engine in a polaris RMK chassis. We modify the drivetrain to make it work, and then we use a haltec standalone to tune the engine for lowest emissions. We're running three cats, an EGR system, an EGR cooler, and ceramic coatings. We're going to run extremely lean, like ~16-18:1 A/F ratio (The ceramic coatings help control detonation). This lowers the hydrocarbon and carbon monoxide levels to near nothing but causes the nitrous oxides to rise exponentially. I need to find information on how to control the NO levels, and the relationship betwteen heat, A/F ratio, and CO, HC, and NO levels.
I'm doing the BAHA challange. Check out the SAE book store. They have lots of info in there. It'll cost a bit of money, but it's worth it.
HC and CO are byproducts of incomplete combustion, thus why when you lean it out they drop. NO is caused by hot combustion. Since lean is hot, this is why you see the incrase is NO emissions. The high temperature in the cylinder causes the Nitrogen in the air to breakdown and form NO. Basically you need to know at what temperature this occurs, and keep the combustion temp below this point. EGR lowers the combustion temperature by slowing it down and reducing the burn rate, but if you put too much exhaust in there your engine won't run because there won't be enough oxygen to support combustion.
If you find your HC and CO contents are too high, you may want to look at a an air injection system.