Vacuum Spark Delay Valve: Description and Operation

Fig. 64 Vacuum Delay Valve:

For some applications a vacuum delay valve, Fig. 64, is used in the vacuum line between the vacuum source and the distributor. The valve delays the operation of the vacuum advance for a specified period of time, depending on the color of the valve (Brown 1-3 seconds; White 4-8 seconds; Green 16-24 seconds). This results in a reduction of the emission of NOx.