Operation Section
-89-
G424E/G430E Electronic Controlled LP and Dual Fuel Engines
(If Equipped)
General Description
The MI-04 is a closed loop system utilizing a
catalytic muffler to reduce the emission level in the
exhaust gas. In order to obtain maximum effect
from the catalyst, an accurate control of the air fuel
ratio is required. A small engine control module
(SECM) uses a heated exhaust gas oxygen sensor
(HEGO) in the exhaust system to monitor exhaust
gas content.
MI-04 LP System
The SECM makes any necessary corrections to the
air fuel ratio by controlling the inlet fuel pressure to
the air/fuel mixer by modulating the fuel trim valve
(FTV) connected to the regulator. Reducing the fuel
pressure leans the air/fuel mixture and increasing
the fuel pressure enriches the air/fuel mixture. To
calculate any necessary corrections to the air fuel
ratio, the SECM uses a number of different sensors
to gain information about the engines performance.
Engine speed is monitored by the SECM through a
variable reluctance (VR) sensor. Intake manifold air
temperature and absolute pressure is monitored
with a (TMAP) sensor. The MI-04 is a drive by wire
(DBW) system connecting the accelerator pedal to
the electronic throttle through the electrical harness,
mechanical cables are not used. A throttle position
sensor (TPS) monitors throttle position in relation to
the accelerator pedal position sensor (APP)
feedback. Even engine coolant temperature and
adequate oil pressure is monitored by the SECM.
The SECM controller has full adaptive learning
capabilities, allowing it to adapt control function as
operating conditions change. Factors such as
ambient temperature, fuel variations, ignition
component wear, clogged air filter, and other
operating variables are compensated.
Smart Coil
Key switch
Foot Pedal
Fuel Filter
Fuel Lock
Converter
SECM
Fuel Trim Valve
Mixer
Distributor
Engine
VR Sensor
Coolant Temp Sensor
Catalytic
Muffler
Oxygen
TMAP
DBW Throttle
Fault Light
Air Cleaner
LP Fuel Line
Coolant Line
TPS
APP
Main
PWR
Relay
VacuumLine
