The name Minneapolis is attributed to Charles Hoag, the city's first schoolteacher, who combined mni, a Dakota Sioux word for water, and polis, the Greek word for city.
EGR valve on top of the inlet manifold of a Saab H engine in a 1987 Saab 90. In internal combustion engines, exhaust gas recirculation (EGR) is a nitrogen oxide (NOx) emissions reduction technique used in petrol/gasoline and diesel engines. EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders.
On the other hand, carbon monoxide is the result of incomplete combustion in the carâs engine which in turn can cause high levels of oxygen. Common Reasons. There are certain causes of gas related smog check failures for each of these gases. Common causes of high levels of NOx or Nitrogen Oxides include advance timing and a faulty EGR system. The EGR System or Exhaust Gas Recirculation System is the main component in the exhaust gas recirculation system.