MBE4000 APPLICATION AND INSTALLATION
6.3
EGR CONTROL VALVES
There are two EGR valves on the MBE4000 – the EGR shutoff valve and the modulated EGR
valve. The EGR valves regulate the
fl
ow of exhaust gases through the EGR system. The EGR
shutoff valve is a pneumatically driven butter
fl
y valve, located at the inlet to the EGR cooler.
The modulated EGR valve is an electronically actuated butter
fl
y valve located on the EGR cold
pipe, after the EGR cooler.
6.4
REED VALVES
The pressure in the exhaust manifold must be higher than the charge air pressure to drive exhaust
gas transport to the engine. The pressure of gases in the exhaust manifold changes over time,
peaking when exhaust valves open. Exhaust gases pass through the reed valves during these
pressure peaks. The reed valves permit transport of exhaust gases only during the time when the
exhaust gases pressure is greater than the charge air pressure.
6.5
EGR MIXER
The purpose of the mixer is to ensure good mixing of the cooled EGR gases with
fi
ltered charge
air. Once the exhaust gases are cooled and have completed their cycle through the EGR system,
they are released into the EGR mixer. The recycled exhaust gases are combined with the charged
air and directed to the cylinders.
All information subject to change without notice.
(Rev. 03/06)
6-5
7SA250 0603
Copyright © 2006 DETROIT DIESEL CORPORATION