TM 9-6115-729-24
FIELD LEVEL MAINTENANCE
TACTICAL QUIET GENERATOR 100 kW, 50/60 Hz MEP-807A/PU-807A
THEORY OF OPERATION
GENERAL
This work package contains functional descriptions of the generator set and explains how TQG functional
systems interact with one another.
ENGINE OVERVIEW
The 100 kW TQG is powered by an in-line six cylinder diesel engine. The firing order of the engine is 1-5-3-6-2-4.
The engine rotation is counterclockwise when the engine is viewed from the flywheel end (rear) of the engine.
The engine uses a turbocharger and an air-to-air aftercooler. The engine cylinders bore is 4.3 inch (110 mm) with
stroke of 5.0 inch (127 mm). Total displacement is 442 cu. in. (7.25L). The engine hydraulic electronic unit
injector system (HEUI) eliminates mechanical components that are used in a pump-and-line system. The HEUI
provides increased control of the timing and increased control of the fuel air mixture. The timing advance is
achieved by precise control of the unit injector timing. Adjusting the injection duration controls engine rpm. An
engine speed sensor provides information to the Engine Control Module (ECM) for detection of cylinder position
and engine rpm. The engine has built-in diagnostics to ensure that all of the components are operating properly.
In the event of a system component failure, the operator will be alerted via the Generator Set Control (GSC)
component of the TQG Electronic Modular Control Panel (EMCP). Numerical codes of the faulty component or
condition are displayed on the GSC. Intermittent faults are logged and stored in the ECM memory.
Engine Control Module
The Engine Control Module (ECM) automatically provides the correct amount of fuel in order to start the engine.
The engine control module is integrated with the engine fuel system and the engine air inlet and exhaust system
to control the fuel delivery and the injection timing electronically. The electronic control module provides timing
control and fuel air ratio control. Injection timing is achieved by the precise control of the injector firing time.
Adjusting the injection duration controls engine rpm. ECM energizes unit injector solenoids in order to start the
injection of fuel and de-energizes the unit injector solenoids to stop the injection of fuel.
Electronic Components
The engine uses three types of electronic components: input, control, and output. Input-components send
variable electrical signals (voltage, frequency, or pulse width (PW)) to the ECM. ECM interprets input signals
about the condition, environment, or operation of the TQG. ECM firmware evaluates input data to
ENGINE SENSORS
Boost Pressure
Boost is defined as the difference between the inlet and outlet pressures of the turbocharger. The atmospheric
pressure sensor on the air inlet to the turbocharger is used to reduce smoke emissions at high altitudes and as
the reference for calculating turbocharger boost pressure. Boost pressure measurements are used to reduce
smoke emissions during acceleration. The outlet pressure sensor is located at the turbocharger outlet and
measures pressure from 3 to 49 psi (20 to 340 kPa).
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