Gadgetory

for ages derided as slow and more noticeably filthy automotive diesel engines went in for a big makeover over the last couple of decades the common rail injection is a form of fuel injection that can spritz diesel into the cylinders at very high psi and very precisely controlled bursts that kind of control of the amount of fuel and how often it sprays into the cylinder combined with turbo charging revolutionize both the power output and co2 emissions coming out of diesel engines starting in the late 90s around 2006 ultra-low sulfur diesel fuel became the norm in the UK Europe and us it reduced the dirty sulphur content in diesel fuel from 500 parts per million to 15 taking that out reduces the energy content in a gallon of fuel slightly but primarily sets the stage for a key pair of cleaning technologies to kick in selective catalytic reduction puts a special catalytic converter in a diesel cars exhaust system inside that can is sprayed a mist of urea fluid that combines with heat and the special metal surfaces in the catalytic converter for a reaction that scrubs diesel emissions way down in several key areas the downside of SCR is that you have to add this expensive plumbing to the car's underside and refill the card supply of urea fluid from time to time typically at 10 to 15,000 mile intervals some dealers will do it for you as a courtesy during routine service or you can do it yourself with a bottle of the stuff from Amazon or an auto parts store it's like adding washer fluid but it's one more thing to fiddle with the TV we love right about now we should have smelled something fishy VW is meeting stringent new u.s. diesel emission standards from 2009 on without SCR on most of its diesels which seemed like a trick no other car maker could pull off as we now know they weren't pulling it off either these events are deeply troubling retrofitting one of these bulky complex scr exhaust systems and urea tank to the affected TDI VW s and Audi's out there is one way VW may have to address the current cars that are on the road and violating emissions standards but what if diesel exhaust could be cleaned up before it's even exhaust that's what they're working on at the Oak Ridge National Labs where they're developing diesel engine tech that injects fuel into the cylinder early in the combustion cycle something which almost defies the definition of a diesel that along with a new breed of sensors to manage the fuel timing precisely based on nuanced real-time measurement of cylinder pressure could be a big break for the diesel engine is by its nature a dirty beast but it's fuel flexibility lovely torque and high MPG keep it an important player in combustion auto engines even if keeping it there requires a constant stream of new cleaning tech or car tech demystified right now at CNN on cars comm click on car tech 101