HUMANISTA MATEMÁTICAS

Before being added to the fuel tank, it is recommended that diesel fuel be processed through an effective fuel filtration facility that removes soft and hard contaminants 2 microns in size and larger. Using unfiltered fuel can result in suction strainer plugging, loss of performance, and over time, serious damage to injectors.

Soft contaminants include water, bacteria, algae, fungi, and waxes. Water must be removed or kept at the lowest possible level, as it is very destructive to fuel system

components. Bacteria, algae, and fungi of the fuel storage tank will show

up as slime on the facilities fuel may with algicide or

fungicide to remove it. Waxes are generally kept in suspension and do not cause problems unless there is an excessively high level of them in the fuel or extremely cold temperatures.

Hard contaminants such as rust, scale, cracking catalyst fines, dirt, and wear metals will be removed by the filters as long as they are changed at regular intervals, (usually monthly).

,

G

G

G

G

G

G

G

G

--

I I I I I I I I I I I I I I I I I I I

G

G

G

G

Cooling System

Introduction

T h e engine cooling system consists of engine driven centrifugal water pumps, replaceable inlet water manifolds an individual jumper line to each liner, cylinder head discharge elbows, and an outlet manifold through which cooling water is

circulated. The centrifugal water pumps (one on an 8 cylinder engine) are mounted on

the accessory drive housing and are driven by the governor drive gear. A representative illustration of the engine cooling system is shown in Figures and

Figure Cooling System Pictorial Diagram

Coolant is drawn from the expansion tank through an aspirator by the water pumps. Pump outlet elbows conduct the water from the pumps to the water inlet manifolds located in each air box. Each manifold is connected at the rear end plate to an aftercooler water inlet pipe.

Radiators Water

Water Detect

Turbocharger

Manifold

Figure Cooling System Schematic Diagram

Each cylinder liner is individually supplied with coolant from the water manifold through a water inlet tube assembly. A deflector is used at each liner water inlet to divert the water and prevent direct impingement on the inner liner wall. The coolant flows upward in the cylinder liner water jacket and enters the cylinder head through 12 discharge holes at the top of the liner. A counter-bore around each hole accommodates a heat dam and a water seal. A water discharge elbow is

to each cylinder head to provide a water passage to the water discharge manifold which extends along the top of the crankcase. The crankcase has two “built-in” siphon tubes inside the water discharge manifold to provide for engine cooling water draining in the

event the level.

3

Figure Coolant Flow

through Power Assembly

,

I '

. . . . . . . . .

In addition to the engine cylinder assemblies, on turbo engines, coolant is also circulated through the aftercooler cores. One condition that has a dramatic effect on

engine performance is the temperature of incoming air for inlet air

temperature is reduced, engine performance is increased. Past

EMD

engines used 2

pass aftercoolers as illustrated in Figure to cool intake air after it had been

compressed by the turbocharger. The coolant was taken off the rear of the main cooling manifolds after the power assemblies.

Figure Two Pass Figure Four Puss

Coolant temperature for the after coolers therefore was limited to the same level as required for the power assemblies. Because the cores were equipped with only two

flanged connections, the coolant flow patterns were different from side to side of the engine resulting in an temperature imbalance between the two banks,

EMD

in partnership with Young Radiator has developed a four pass aftercooler which recycles the water through the cooler before discharge to provide a higher cooling capacity. The cores have been equipped with four connection flanges to allow for the application of any four pass core to either the right or left engine bank and keep the coolant pattern the same between banks.

Coolant from the power assemblies and the aftercoolers is collected in the main water chamber in the top center of the engine. From the engine, water is directed out the 'Y" pipe to the radiator assemblies. Electrically driven cooling fans move air

through the radiators, which absorbs heat from the coolant. Water temperature control is facilitated by the use of temperature switches that control fan and shutter operation. Newer systems use temperature sensors, and fan shutter control is handled by

a microprocessor.

The coolant returns from the radiators to the lube oil cooler where it absorbs some of the excess heat from the lube oil. The cooler consists of a radiator section mounted in a steel tank.

3

From the cooler, the coolant goes back to the aspirators to repeat the cycle. When the engine is first started, coolant is drawn from the expansion tank as there is no return from the radiators at this point. When there is sufficient return flow, the water level in the tank stabilizes.

Note that part of the water from the engine mounted pumps is piped to the air compressor. There are no valves in the line, thus cooling will be provided whenever the engine is running. Upon leaving the air compressor, water is piped back to the water tank for re-circulation

In document Reporte de Investigación presentado a la Facultad de Educación para optar al Grado de Magíster en Educación (página 61-66)