Chrysler 1997 Stratus Convertible RHD Service Manual page 1189

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EXHAUST GAS RECIRCULATION (EGR) SYSTEM
DESCRIPTION AND OPERATION
EXHAUST GAS RECIRCULATION (EGR)
SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
DIAGNOSIS AND TESTING
EGR GAS FLOW TEST
EGR SYSTEM ON-BOARD DIAGNOSTICS . . . . 24
EGR SYSTEM ON-BOARD DIAGNOSTICS . . . . 24
EGR SYSTEM TEST
EGR VALVE CONTROL (TRANSDUCER)
TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
DESCRIPTION AND OPERATION
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
Refer to Monitored Systems - EGR Monitor in this
group for more information.
The EGR system reduces oxides of nitrogen (NOx)
in engine exhaust and helps prevent detonation
(engine knock). Under normal operating conditions,
engine cylinder temperature can reach more than
3000°F. Formation of NOx increases proportionally
with combustion temperature. To reduce the emission
of these oxides, the cylinder temperature must be
lowered. The system allows a predetermined amount
of hot exhaust gas to recirculate and dilute the
incoming air/fuel mixture. The diluted air/fuel mix-
ture reduces peak flame temperature during combus-
tion.
The EGR system consists of (Fig. 1), (Fig. 2), and
(Fig. 3):
• EGR tube
• EGR valve
• Electric EGR Transducer
• Connecting hoses
The electric EGR transducer contains an electri-
cally operated solenoid and a back-pressure trans-
ducer (Fig. 4). The Powertrain Control Module (PCM)
operates the solenoid. The PCM determines when to
energize the solenoid. Exhaust system back-pressure
controls the transducer.
When the PCM energizes the solenoid, vacuum
does not reach the transducer. Vacuum flows to the
transducer when the PCM de-energizes the solenoid.
When exhaust system back-pressure becomes high
enough, it fully closes a bleed valve in the trans-
ducer. When the PCM de-energizes the solenoid and
back-pressure closes the transducer bleed valve, vac-
uum flows through the transducer to operate the
EGR valve.
. . . . . . . . . . . . . . . . . . 25
. . . . . . . . . . . . . . . . . . . . 25
VACUUM INLET EGR TUBE
EMISSION CONTROL SYSTEMS
INDEX
page
EGR VALVE LEAKAGE TEST . . . . . . . . . . . . . . 26
REMOVAL AND INSTALLATION
EGR TUBE—2.0L . . . . . . . . . . . . . . . . . . . . . . . 28
EGR TUBE—2.4L . . . . . . . . . . . . . . . . . . . . . . . 29
EGR TUBE—2.5L . . . . . . . . . . . . . . . . . . . . . . . 29
EGR VALVE AND TRANSDUCER—2.0L . . . . . . 27
EGR VALVE AND TRANSDUCER—2.4L . . . . . . 27
EGR VALVE AND TRANSDUCER—2.5L . . . . . . 27
SPECIFICATIONS
TORQUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Fig. 2 EGR Control Valve—2.5L
De-energizing the solenoid, but not fully closing the
transducer bleed hole (because of low back-pressure),
varies the strength of vacuum applied to the EGR
EGR SOLENOID PRESSURE EGR TRANSDUCER BACK
Fig. 1 EGR System—2.4L
EGR BACK VACUUM EGR VALVE SOLENOID TO EGR VALVE TRANSDUCER PRESSURE OUTLET HOSE AND
25 - 23
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