maintenance or any extended idle periods. This unit
Jacket Water Cooling System
consists of an electric motor directly connected to a
The jacket water cooling system uses fresh water,
pump. It has local start/stop controls and remote start
circulated by a centrifugal pump, to keep the engine
controls and monitoring adjacent to the EPCC.
cool. The jacket water system also cools the lube oil and
Resistance Temperature Detectors. RTDs are
gives up heat to the waste heat system.
provided at both the engine inlet (cooler outlet) and the
COMPONENTS. The Detroit Diesel's jacket
pump discharge. The inlet RTD provides a signal to the
water cooling system contains both engine-mounted and
EPCC to actuate an audible and visual alarm if the oil
off-engine components. Let's take a look at these
temperature exceeds 225F. The signal also allows
components and how they work together.
demand display or data logger printout. The pump
Engine-Mounted Components. The engine-
discharge RTD provides a continuous display at the
mounted components include the following units:
EPCC.
Water pump and inlet adapter
Pressure Transucers. Pressure transducers are
Water inlet and outlet manifolds
located at the engine inlet, the oil manifold, and the
pump discharge. The manifold transducer provides
Jacket water outlet
continuous display and actuates an audible and visual
These components are mounted on or to the engine
alarm at the EPCC when the oil pressure drops to 48
itself.
psig. The discharge transducer gives a demand display
Off-Engine Components. The off-engine
only. The engine inlet transducer provides a gauge
components include the following units:
readout on the local control panel.
Level and Pressure Switches. A level switch
A 30-gallon jacket water expansion tank
mounted in the oil sump provides an audible and visual
A 5-gallon water treatment tank
alarm when the sump level drops 9.5 inches below the
Cooler
full mark.
Two pressure switches are provided on the system.
Waste heat exchanger
One switch actuates an audible and visual alarm. The
Temperature regulating valve
other switch automatically shuts the engine down when
Lube oil cooler
oil pressure drops below 42 psig.
These components are mounted off the engine and are
Ventilation System. The crankcase ventilation
located in the ship's piping system.
system removes harmful vapors from the crankcase,
gear train, and valve compartments. The crankcase is
OPERATION. The water pump is mounted on the
vented through four breather assemblies. These
engine front cover and is driven by the front
assemblies are mounted on the rocker covers to an
crankshaft gear through two idler gears. It draws a
suction from the off-engine system and pumps water
electrostatic vent fog precipitator. The breather
into the cylinder block, around the cylinder liners, and
assemblies are connected to the precipitator by four
through the cylinder heads, to the water outlet
rubber hoses.
manifolds. The flow divides in the water outlet
The precipitator is a two-stage device that removes
manifolds with approximately 60 gallons per minute,
oil fog and particulate matter from the airstream flowing
discharging to the exhaust manifolds at 30 gallons per
from the breather vents. It is designed for continuous
minute per side.
operation in a maximum ambient air temperature of
A flow of approximately 400 gallons per minute
225F and a maximum flow rate of 150 cubic feet per
discharges into the jacket water outlet. From the jacket
minute (cfm). It is most efficient in the 50 to 100 cfm
water outlet, the water then returns to the off-engine
range.
system for cooling.
Now that you have taken a look at the components
Monitoring, Control, and Regulating
of the lube oil system, let's look at the Detroit Diesel's
Components. Two RTDs are provided in the jacket
water outlet line. One RTD sends a signal to the EPCC
cooling system.
