The blog began with me leaving a job, so it makes sense to relay a bit about the work I've ventured into. My new employer is called Tenneco, and they are an auto parts supplier conglomerate of sorts. They have two main businesses: exhausts (tailpipe to mufflers up to the engine) and suspension components (shocks and struts). For each business they're the top American supplier and thus the bottom line is heavily tied to the Big 3. I work with the exhaust side, which is all based in two buildings in Jackson County, MI. My job is in Grass Lake, a tiny town right off of I-94 between Ann Arbor and Jackson. 25-minute door-to-door travel time for me, but a fair amount of miles every day. Here's the as-the-car-drives-it commute for perspective:
View Commute TO Grass Lake in a larger map
So it's in the country. Anyway, I still work on "diesel aftertreatment". That's the specialized niche I've been in since I left locomotives and worked at International Truck. The premise is that diesel engines are under a steady tightening of regulations that are bringing all of their emissions in-line with modern gasoline cars by 2013. The first big new technology to enable this are "Diesel Particulate Filters" which are ceramic bricks that fit in the exhaust where the muffler would be and trap 100% of the black soot that diesel engines make. For cars and trucks, these were mandated in 2007 and I've now worked on the first and second generations of this technology at my prior two employers. The second new technology is called "NOx aftertreatment" which is a slightly-less-standardized technology to remove Nitrogen oxides from the engine exhaust. Cars have had catalytic converters for decades to do this, but that technology will not work with diesels. NOx causes smog in major cities and is poisonous in high-risk exposure. So new systems were invented that use liquid urea sprayed into the exhaust to convert the NOx to harmless nitrogen. These systems are just hitting the road now with cars and trucks and all engines must be all the way up to the regulations in the next couple of years.
So what's different than at GM? Well, Tenneco is entering the business of selling complete aftertreatment systems to diesel engine makers to handle compliance with regulations. While a huge company like GM develops the controls of system on it's own in it's own trucks, a smaller company that makes, say diesel forklifts or construction equipment doesn't have those resources. So what I work on is intended to be a "bolt-on" system. Right now I'm just working with the soot filters, but I have a project lined up later in the year for a NOx customer.
The technology is a little different at Tenneco. With the soot filters the major challenge is how the soot is periodically cleaned out of the filter to prevent clogging. This is called a "regen" and involves very high heat in the exhaust pipes, up to 1200 degrees. Where GM uses extra fuel in the exhaust being oxidized in a ceramic catalyst to make the controlled heat while driving, Tenneco is offering a diesel fuel burner for the exhaust. With an actual flame that I have to control - actually quite similar to that within a jet engine. The advantage is that a burner can make heat without any changes to the operation of the engine. So we keep our hands off of our customers engines and just work with the exhaust.
Here's a picture of the system, without any particular labeling, on the back of my Japanese forklift (counterweight removed). It has new challenges to me and I think it's interesting work. The way we're implementing a burner, it is the first of it's kind in the industry.
Work is boring, so enough for now... More to come