1A-8 Engine Control System EGR (Exhaust Gas Recirculation) Valve In order to decrease NOx (nitrogen oxide) in the exhaust gas, an EGR system is employed. The EGR valve is vacuum control type. Legend 1. Diaphragm 2. Valve 3. Exhaust gas 4. Vacuum LNW21ASF000101 1 2 3 3 4 LNW21ASF000201