A clean sweep! Gary Cundliffe shows how to deal with the problem of a clogged-up EGR valve on the Mk 4 Golf TDI engine

摘要

TO MEET EMISSIONS targets on modern diesel engines, most manufacturers use an Exhaust Gas Recirculation (EGR) valve to redirects quantity of exhaust gas back into the inlet manifold to be mixed with the incoming air and fuel mixture. Because exhaust gases have already been through the combustion process, they don't burn again when they are recirculated, so they displace some of the normal intake charge, effectively diluting the ainfuel mixture. This slows and cools the combustion process by several hundred degrees, which has a direct effect on the amount of NOx (nitrous oxide) produced, reducing emissions.