HYDRAULIC STARTING SYSTEM (HYDROSTARTER)
pressure is forced out of the accumulator, by the
The Hydrostarter System schematically illustrated in Fig.
expanding nitrogen gas, and flows into the starting
6 is a complete hydraulic system for starting internal
motor which rapidly accelerates the engine to a high
The system is automatically
cranking speed. The used fluid returns directly to the
recharged after each start, and can be manually
reservoir from the starter.
recharged. The starting potential remains during long
periods of inactivity, and continuous exposure to hot or
The engine-driven charging pump runs continuously
cold climates has no detrimental effect upon the
during engine operation and automatically recharges the
Hydrostarter system. Also, the Hydrostarter torque for a
accumulator. When the required pressure is attained in
given pressure remains substantially the same
the accumulator, a valve within the pump body opens
regardless of the ambient temperature.
and the fluid discharged by the pump is by-passed to the
reservoir. The system can be shut down and the
The Hydrostarter system consists of a reservoir, an
pressure in the accumulator will be maintained.
engine-driven charging pump, a hand pump, a piston
type accumulator, a starting motor and connecting
The precharge pressure of the accumulator is the
hoses and fittings.
pressure of the nitrogen gas with which the accumulator
is initially charged. This pressure must be checked
before the system pressure is raised for the initial
engine start. To check the precharge pressure, open
Hydraulic fluid flows by gravity, or a slight vacuum, from
the relief valve, on the side of the hand pump,
the reservoir to either the engine-driven pump or the
approximately 1/2 turn, allowing the pressure gage to
return to zero. Close the relief valve and pump several
outlet at high pressure flows into the accumulator and is
strokes on the hand pump. The gage should show a
stored at 3250 psi under the pressure of compressed
rapid pressure rise from zero to the nitrogen precharge
pressure, where it will remain without change for several
additional strokes of the pump.
When the starter is engaged with the engine flywheel
ring gear and the control valve is opened, fluid under
Fig. 6. Schematic Diagram of Hydrostarter System Showing Oil Flow