Specifications
EPA04 MBE 4000 ENGINE OPERATOR'S GUIDE
The constant-throttle valves u se the
air that escapes through them o n the
compression stroke to provide braking
force. The constant throttles are small
valves which are bu ilt into t h e cylinder
heads. W hen open, a link is created
between the combustion chamber and
the exhaust po rt.
The engine brake is activated by the
DDEC-VCU. In engine braking m ode,
an engine rpm range of up to 2,500
rpm can be used by the operator.
2,500 rpm, however, may never be
exceeded. The engine is turned off
automatically when the engine rpm is:
□ Below 900 rpm for Allison
Automatic Transmissions
□ Below 1100 rpm for all other
transmissions
Also, the engine brake is automatically
turned off when the accelerator pedal
is pressed.
NOTE:
When in emergency running mode
(constant rpm), the engine brake can
be activated only w hen the engine is
in overrun. When constant rpm has
been attained, the engine brake is
automatically turned off.
Turbo B rake, Optional
For high braking ou tpu t, the MBE
4000 engine can be equ ipp ed with an
optional turbo brake. The turbo b rake
increases the air mass flow throug h the
engine to provide very high braking
horsepower.
The turbo brake can be operated either
manually or automatically, through
the cruise control function .
Because the charge air pressure is
maintained at a high level during
braking, full throt tle respon se is
available immediately, if the operator
desires it, without any turbo lag.
The turbo brake is m aintenance-free,
highly reliable, and adds virtually no
weight to the engine.
Exhaust Gas Recirculation
The purpose of the Exhaust Gas
Recirculation (EGR) System is to
reduce en gin e exhaust gas emissions
in accordance with EPA regulations.
The MB E 4000 engines for
on-highway EPA 2004 regulation
applications use a cooled EGR system
consisting of an EGR cooler, EGR
control valves, reed valves, and an
EGR mixer.
In the co oled EGR system, part of the
exhaust gasses from the front three
cylinders are routed from the exhaust
manifold through the EGR cooler, past
control and reed valves, and are mixed
with the in take manifold charge air.
All information subject to change without notice. (Rev. 04/08) 17
DDC-SVC-MAN-0056 04/0 8 Copyright © 2008 DETROIT DIESEL CORPORATION