Mi-04 Electronic Throttle - Daewoo G420E Service Manual

MI-04 Electronic Throttle

Conventional throttle systems rely on mechanical
linkage to control the throttle valve. To meet
fluctuating engine demands a conventional system
will typically include throttle valve actuators designed
to readjust the throttle valve opening in response to
engine demand, together with idle control actuators or
idle air bypass valves.
Figure 20
In contrast, the MI-04 system uses electronic throttle
control (ETC). The SECM controls the throttle valve
based on engine RPM, engine load, and information
received from the Acceleration Pedal. Two mutually
opposed potentiometers on the Acceleration Pedal
assembly monitor accelerator pedal travel. The
electronic throttle used in the MI-04 system is a
Bosch 32mm Electronic Throttle Body DV-E5 (Figure
20). The DV-E5 is a single unit assembly, which
includes the throttle valve, throttle-valve actuator (DC
motor) and the throttle position sensor (TPS) (Figure
21).
Figure 21
Tier
G420E/G424E
Gear Drive
Bosch 32mm Electronic Throttle Body DV-E5
Picture courtesy of Robert Bosch GmbH
LP Engine
The SECM calculates the correct throttle valve
opening that corresponds to the driver's demand,
makes any adjustments needed for adaptation to the
engine's current operating conditions and then
generates a corresponding electrical (driver) signal to
the throttle-valve actuator.
There are multiple limp-home modes available with
ETC. 1. If the throttle itself is suspected of being
inoperable, the SECM will remove the power to the
throttle motor. When the power is removed, the
throttle blade returns to its "default" position,
approximately 7% open. 2. If the SECM can still
control the throttle but some other part of the system
is suspected of failure, the SECM will enter a
"Reduced Power" mode. In this mode, the power
output of the engine is limited by reducing the
maximum throttle position allowed. 3. In some cases,
the SECM will shut the engine down. This is
accomplished by stopping ignition, turning off the fuel,
and disabling the throttle.
In place of a dual TPS design (TPS1 and TPS2), the
SECM calculates correct throttle position (Predicted
TPS) based on RPM and MAP and compares this to
the actual throttle position, based on TPS1. The
SECM continuously checks and monitors all sensors
and calculations that effect throttle valve position
whenever the engine is running. If any malfunctions
are encountered, the SECM's initial response is to
revert to redundant sensors and calculated data. If no
redundant signal is available or calculated data
cannot solve the malfunction, the SECM will drive the
system into one of it's limp-home modes or shut the
engine down, storing the appropriate fault information
in the SECM.
Throttle Plate
DC Drive Motor
22 System Operational Overview