Chapter 1 Dual Fuel System Component Modules
The dual fuel system is
composed of a number of modules shown on the schematic
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The Diesel Module comprises
the Diesel Actuator that limits the diesel delivery
during dual fuel engine operation. The Diesel Actuator
consists of a stepping motor driven lead screw mounted
on the end of the injector pump to restrict the movement
of the control rack. It also includes a rack stop switch
mounted in the end of the bios spring housing to allow
accurate initialisation.
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Figure 1 Diesel actuator |
Part
2 Gas Module
The gas module comprises
all the hardware components used to control the delivery
of gas when the engine is operating in dual fuel mode.
The module consists of the components listed below.
The gas valve receives 1 MPa regulated gas pressure
and delivers a variable gas pressure, controlled by
a pressure feed back servo, to the engine. The gas flow
has been corrected for temperature variation and is
delivered into the inlet air via the injector orifice
that is mounted on the air throttle housing.
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Figure 2 Gas module |
| Components
included: |
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Gas valve |
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Delivery Pressure sensor |
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Delivery Temperature sensor |
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Gas valve clamp |
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Gas injector |
Part
3 Regulator Module
This takes gas from the
storage cylinders and regulates the pressure to approx
1 Mpa.
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Part 3 Regulator Module |
| Components
included: |
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Primary regulator |
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Lock-off solenoid |
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Regulated pressure gas hose |
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Coolant hoses |
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Storage pressure sensor |
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Gas filter |
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Relief valve |
A sensor measures the storage pressure and the pressure
is displayed on the driver’s console. The storage
pressure (up to 20 MPa) is reduced to 1 MPa by the primary
regulator and a lock off solenoid is included with the
regulator.
Part
4 Air Throttle Module
The air throttle module
is mounted between the after cooler radiator and the
inlet manifold and reduces the air flow so as to maintain
the best air/fuel ratio for low emissions and high fuel
efficiency.
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Part 4 Air Throttle Module |
| Components
included: |
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Air throttle housing |
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Stepping motor driving through a toothed belt |
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Throttle plate |
The air throttle housing
is also used to mount the Gas Module and the IMAT and
IMAP sensors.
The status module consists
of all the other sensors fitted to the engine that provide
the information required to control the engine performance.
| Components
included: |
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Demand sensor |
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The Demand sensor supplies the driver requirements
to the controller |
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Demand
Sensor consists of: |
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Mount |
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Activator |
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Hub |
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Sensor |
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Figure 5 Demand
Sensor |
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RPM Sensor |
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RPM sensor supplies the engine speed in revolution
per mints |
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Figure 6 RPM Sensor |
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IMAT (Inlet Manifold Air Temperature)
sensor |
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The IMAT sensor allows the correct air and
fuel value appropriate for engine |
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Figure 7 IMAT sensor |
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IMAP (Inlet Manifold
Air Pressure) sensor |
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The IMAP sensor provides data for
the correct gas and air appropriate for engine.
The sensor is mounted on the ECU printed circuit
board and is connected to the manifold by a hose
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Coolant temperature sensor |
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The coolant sensor is mounted on
the engine and allows the engine to operate on
diesel until the coolant reaches the minimum temperature
for gas operation. |
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Figure 8 Coolant
sensor |
This module provides interface
with the DieselGas control system for Drivers, Engineers,
Technicians and Mechanics.
The “on gas” light is on when the system
is using gas. The “fault” light is on when
a system fault occurs and the operating system then
switches to diesel operation. The fault light flashes
a “fault code” when a fault has occurred
and the ignition is switched off and on. The RS232 communications
port allows the use of DGTech to monitor the engine
operation, retrieve logs, analyse faults, set calibrations
and modify settings.
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Figure 9 Drivers display |
| Components
included: |
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Two warning lights mounted in the drivers’
console - “on gas” and “Fault”
lights |
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Substitution/storage LCD gauge to indicate either
substitution percentage or the pressure of gas
remaining in the Storage cylinders |
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A gas/diesel selection switch to select the
engine operating mode |
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An RS232 communication port for the laptop computer
using DGTech interface software that consists
of the DieselGas technician interface programme
and a laptop (note book) computer |
Part 7 Control
Module ECU
This is the electronic
controller hardware and include the embedded software,
fuelling tables, setting and calibrations that set the
performance of the engine.
Components included.
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Figure 10 Diesel
Gas Controller [DGC] |
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Printed circuit board |
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Controller box |
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IMAP sensor |
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Wiring loom plug |
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Heat sink box |
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Wiring loom with plug and socket |
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The microprocessor |
Part 8 Harness
Module
The harness module provides
power supply and sensor connection to the controller.
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Figure 11 Harness
Module |
(Not supplied by DieselGas)
| The storage module
includes : |
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Storage cylinders on the vehicle |
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Figure 12 Gas Cylinders |
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Fill valve and master
shut off valve |
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