Doosan D20S-5 Operation & Maintenance Manual page 86

Operation Section Operation Section
Electronic c Controlled Spark-Ignition Engines Electroni
G420FE Engine and G424FE Engine G420FE Engine and G424FE Engine
EMS (Engine management system) of G420FE EMS (Engine management system) of G420FE
engine and G424FE engine is a closed loop system engine and G424FE engine is a closed loop system
utilizing a 3-way catalytic muffler to reduce the utilizing a 3-way catalytic muffler to reduce the
emission level in the exhaust gas. In o emission level in the exhaust gas. In order to obtain
maximum effect from the catalyst, an accurate maximum effect from the catalyst, an accurate
control of the air fuel ratio is required. A small control of the air fuel ratio is required. A small
The SECM makes any necessary corrections to the The SECM makes any necessary corrections to the
air fuel ratio by controlling the inlet fuel pressure to air fuel ratio by controlling the inlet fuel pressure to
the air/fuel mixer by modulating the dual fuel trim the air/fuel mixer by modulating the dual fuel trim
valves (FTV) connected to the regulator. Reducing valves (FTV) connected to the regulator. Reducing
the fuel pressure leans the air/fuel mixture and the fuel pressure leans the air/fuel mixture and
increasing the fuel pressure enriches the air/fuel increasing the fuel pressure enriches the air/fuel
mixture. To calculate any necessary corrections to mixture. To calculate any necessary corrections to
the air fuel ratio, the SECM uses a number of the air fuel ratio, the SECM uses a number of
different sensors to gain information about the different sensors to gain information about the
engine's performance. Engine speed is monitored engine's performance. Engine speed is monitored
by the SECM through a variable reluctance (VR) or by the SECM through a variable reluctance (VR) or
Hall Effect sensor. Intake manifold air temperature Hall Effect sensor. Intake manifold air temperature
and absolute pressure are monitored with a TMAP and absolute pressure are monitored with a TMAP
sensor. MI-07 is a drive-by-wire (DBW) system sensor. MI-07 is a drive-by-wire (DBW) system
connecting the accelerator pedal to the electronic connecting the accelerator pedal to the electronic
throttle through the electrical harness; mechanical throttle through the electrical harness; mechanical
cables are not used. A throttle position sensor cables are not used. A throttle position sensor
(TPS) monitors throttle position in relation to the (TPS) monitors throttle position in relation to the
accelerator pedal position sensor (APP) command. accelerator pedal position sensor (APP) command.
Controlled Spark-Ignition Engines
rder to obtain
EMS schematic of G420FE Dual fuel engine EMS schematic of G420FE Dual fuel engine
-83- -83-
engine control module (SECM) uses two heated engine control module (SECM) uses two heated
exhaust gas oxygen sensors (HEGO) in the exhaust gas oxygen sensors (HEGO) in the
exhaust system to monitor exhaust gas content. exhaust system to monitor exhaust gas content.
One HEGO is installed in front of the catalytic One HEGO is installed in front of the catalytic
muffler and one is installed after the catalytic muffler and one is installed after the catalytic
muffler. muffler.
Even engine coolant temperature and adequate oil Even engine coolant temperature and adequate oil
pressure are monitored by the SECM. The SECM pressure are monitored by the SECM. The SECM
controller has full adaptive learning capabilities, controller has full adaptive learning capabilities,
allowing it to adapt control function as operating allowing it to adapt control function as operating
conditions change. Factors such as ambient conditions change. Factors such as ambient
temperature, fuel variations, ignition component temperature, fuel variations, ignition component
wear, clogged air filter, and other operating wear, clogged air filter, and other operating
variables are compensated. variables are compensated.
MPI (multi-point injection) is used for this system. MPI (multi-point injection) is used for this system.
Fuel injection pressure and flow rate depend on Fuel injection pressure and flow rate depend on
engine-specific fuel injection requirements. A engine-specific fuel injection requirements. A
variety of regulators and injectors can be used to fit variety of regulators and injectors can be used to fit
individual needs. The gasoline fuel pressure individual needs. The gasoline fuel pressure
regulator is a one-way, non-return configuration. All regulator is a one-way, non-return configuration. All
gasoline specific components are automotive gasoline specific components are automotive
production parts and validated to strict automotive production parts and validated to strict automotive
standards. Four (4) sequential injection channels standards. Four (4) sequential injection channels
are supported. are supported.