== EGR vacuum switching valve == Despite the rather lengthy name the EGR-VSV (exhaust gas recirculation vacuum switching valve) does little more than allow vacuum to flow through the system depending on engine coolant temperature.
A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. The most common double bond, that is between two carbon atoms, can be found in alkenes. Many types of double bonds exist between two different elements. For example, in a carbonyl group with a carbon atom and an oxygen atom. Other common double bonds are found in azo compounds (N=N), imines (C=N) and sulfoxides (S=O).
Definition of DOUBLET. 1. : a man's close-fitting jacket worn in Europe especially during the Renaissance.edical Definition of DOUBLET. 1. : something consisting of two identical or similar parts: as a: a lens consisting of two components b: a spectrum line having two close components. 2. : a set of two identical or similar things; especially: one of nine pairs of microtubules found in cilia and flagella.