EC/Emission Control Systems — Exhaust Gas Recirculation (EGR) System (7M-GTE), page 16

EC-16     EMISSION CONTROL SYSTEMS — Exhaust Gas Recirculation (EGR) System (7M-GTE)

EXHAUST GAS RECIRCULATION (EGR) SYSTEM (7M-GTE)

(1)
EGR Vacuum
Modulator
                                                                                      EGR Port
EGR Valve
                                                                                      VSV
                                                                                      E···E
                                                                     ECU
                                                                                      EGR
VSV                                                                                   Vacuum
                                                                                      Modulator
                                                      EGR Cooler                      EGR
                                                                                      Valve

EC3330                                                                                EG2283

(2)
                            EGR Port

                            VSV
                            E···E
              ECU

              EGR
              Vacuum
              Modulator
EGR Cooler                                EGR
                                          Valve

                                                                                      EG2380

To reduce NOx emissions, part of the exhaust gases are recirculated through the EGR valve to the intake manifold to lower
the maximum combustion temperature.

Coolant          VSV          Throttle Valve      Pressure in the EGR     EGR Vacuum        EGR           Exhaust Gas
Temp.                         Opening Angle       Valve Pressure Chamber  Modulator         Valve

Below 57°C       CLOSED
(135°F)          (E—G)                            —                       —                 CLOSED        Not
                                                                                                           recirculated

Above 63°C       OPEN         Positioned below
(145°F)          (E—G)        EGR port            (1)                     —                 CLOSED        Not
                                                                                                           recirculated
                              Positioned above
                              EGR port            (2)                     *                 CLOSES passage OPEN         Recirculated
                                                                                            to atmosphere               (Increase)

* When the throttle valve is positioned above the EGR port, the EGR vacuum modulator will close the atmosphere
  passage and open the EGR valve to increase the EGR gas, even if the exhaust pressure is insufficiently low.