INTRODUCTION TO THE HMMWV - OD1615 - LESSON 4/TASK 1
vacuum-actuated diaphragm that receives its vacuum supply from the engine.
(2) Heater Control Knobs and Valves.
The heater tore on the HMMWV
has a mechanically actuated, mechanically controlled butterfly valve that is
opened, adjusted, and closed by the operator pulling a control knob. This
control knob is connected to one end of a cable; the other end is connected
to the butterfly valve. When the operator pulls the knob, the cable pulls
the valve actuating lever, opening the valve.
There is also a cable
operated flapper valve that allows the operator to direct the air to either
the windshield vents or to the cab outlet.
(3) Blower Motor. The blower motor is a simple electric motor that
drives a circular fan, commonly referred to as a squirrel cage. The blower
motor on the HMMWV is controlled by a three-position switch which allows the
operator to select the fan speed. The fan speed selections are OFF-LOW-HI.
The switch, in conjunction with a multiple element resistor, provides the
circuitry to make these motor selections possible.
m. Trailer Receptacle.
The HMMWV trailer receptacle, mounted on the
rear of the vehicle body, is protected by a spring-loaded door and is
compatible with all standard military trailer wiring circuits.
n. Slave Receptacle. A slave receptacle, located on the front side of
the battery box, provides for inter-vehicle cable-starting.
The slave
receptacle is compatible with all NATO vehicles.
o. Glow Plugs.
Diesel engines of the prechamber design, like the
HMMWV, require a preheating glow plug extending into the prechamber to aid
in starting when cold. The plugs are located in the cylinder head, below
each injector nozzle.
When the RUN/START switch is placed in the RUN
position, the glow plugs are energized and air in the prechamber is heated
to approximately 1400 F. In 0 F weather, the glow plugs will preheat the
prechamber in six seconds; the engine will then be easier to start.
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