1. A PROJECT REPORT ON
FOR
DIESEL LOCO SHED, KRISHNARAJAPURAM
IN PARTIAL FULFILLMENT OF INTERNSHIP PROGRAM FOR CAREER DEVELOPMENT
DURING THE PERIOD 20TH JUNE TO 6TH JULY 2013
BY
MONISH U R
M S RAMAIAH INSTITUTE OF TECHNOLOGY

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ACKNOWLEDMENTS
A summer internship is a golden opportunity for learning and self-development. I
consider myself very lucky and honored to have so many wonderful people lead me
through the completion of my summer internship.
My grateful thanks to Mr. Srinivasulu, Sr DME/DLS/KJM for providing me with this
opportunity to undertake an internship program in Fuel Injection System of HHP
Locomotives at the Diesel Loco Shed, KJM, SWR.
I would also like to thank Mr. Madhusudan, JE/DLS/KJM who in spite of being
extraordinarily busy with his duties, took time to hear, guide and keep me on the
correct path. I would not know where I would have been without him. A humble
Thank You Sir.
Mr. Eldo, SSE/DLS/KJM monitored my progress and arranged all the facilities to make
life easier. I would like to take this moment to acknowledge his help gratefully.
Last but not least, I would like to thank the staff DLS/KJM who shared valuable
information that helped in the successful completion of this project.
MONISH UR

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CONTENTS
SL. NO. TITLE PAGE NO.
1. Introduction to Fuel Injection Systems 03
2. General Motors ElectroMotive Diesel Engine Fuel System 04
3. Mechanical Unit Injector 08
4. Fuel System Troubleshooting 11
5. Scheduled Maintenance 13
6. Calibration of Injectors 14
7. Bibliography 15

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Diesel Loco Shed, Krishnarajapuram
Diesel Loco Shed, Krishnarajapuram is a prime maintenance facility of South Western Railway, for
maintenance of Main line and Shunting Diesel Electric Locomotives. The locomotives maintained by
this shed are powering Passenger and Goods trains and running as far as Ahmedabad. The Shed is
awarded ISO 9001:2000 Quality Management System, and is known for its excellent work culture.
Diesel Loco Shed, Krishnarajapuram was established in the year 1983. During the last 20 years, the
Shed has been catering to the needs of the Broad Gauge system of Southern, South Central, Central
and South Western Railways. The shed is known for its excellent quality of workmanship and work
culture all over the railway system. It has well designed and well laid out facilities to undertake
maintenance of Broad Gauge Main Line and shunting locomotives. Presently, the activities in Diesel
Loco Shed, Krishnarajapuram are supported by about 500 employees directly.
With the Master Plan of Railway Board, KJM shed will ultimately hold 150 locos. With this
proposed plan the facilities got further more added up with the project cost of Rs.12.66 Crores
during 1999-2000. Under this project, the covered area is further increased by 2090 sqm leading to
the total of 11080 Sqm. Similarly Loco holding also got improved up to the present level of 97
Locos (July 2004).

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Introduction to Fuel injection Systems
Fuel injection is a system for admitting fuel into an internal combustion engine. It has become the
primary fuel delivery system used in automotive engines, having replaced carburetors during the
1980s and 1990s. A variety of injection systems have existed since the earliest usage of the internal
combustion engine.
The primary difference between carburetors and fuel injection is that fuel injection atomizes the
fuel by forcibly pumping it through a small nozzle under high pressure, while a carburetor relies
on suction created by intake air accelerated through a Venturi tube to draw the fuel into the
airstream.
Modern fuel injection systems are designed specifically for the type of fuel being used. Some
systems are designed for multiple grades of fuel (using sensors to adapt the tuning for the fuel
currently used). Most fuel injection systems are for gasoline or diesel applications.
Objectives
The functional objectives for fuel injection systems can vary. All share the central task of supplying
fuel to the combustion process, but it is a design decision how a particular system is optimized.
There are several competing objectives such as:
 Power output
 Fuel efficiency
 Emissions performance
 Ability to accommodate alternative fuels
 Reliability
 Drivability and smooth operation
 Initial cost
 Maintenance cost
 Diagnostic capability
 Range of environmental operation
 Engine tuning
The modern digital electronic fuel injection system is more capable at optimizing these competing
objectives consistently than earlier fuel delivery systems (such as carburetors).
Environmental benefits
Fuel injection generally increases engine fuel efficiency. With the improved cylinder-to-cylinder fuel
distribution of multi-point fuel injection, less fuel is needed for the same power output (when
cylinder-to-cylinder distribution varies significantly, some cylinders receive excess fuel as a side
effect of ensuring that all cylinders receive sufficient fuel).
Exhaust emissions are cleaner because the more precise and accurate fuel metering reduces the
concentration of toxic combustion byproducts leaving the engine, and because exhaust cleanup
devices such as the catalytic converter can be optimized to operate more efficiently since the
exhaust is of consistent and predictable composition.

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General Motors Electro Motive Diesel Engine Fuel System
The fuel System in responsible for supplying fuel to the diesel engine in the correct quantity at the
required time according to engine requirements. To do this, the fuel must be supplied, filtered,
pressurized, metered and injected.
The system may be divided into two parts Supply side and
delivery side.
Supply
The supply side of the fuel system consists of the fuel tank, fuel
pump, filters and piping. Fuel is drawn from the tank through a
suction strainer by the fuel pump. The strainer has a screen type
element that removes large debris from the fuel. This protects
the pump against damage from foreign material.
The gear type fuel pump may be driven by a DC or AC motor.
The pump is designed to ensure adequate fuel supply at all
engine speeds.
The Primary fuel filters typically consist of one or two 13 micron filters located in canister type
housings. These filters come with a bypass valve, should the filters become plugged, and the back

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pressure to the fuel pump will increase. When the
pressure difference across the bypass valve reaches 30
psi, the valve will open diverting the fuel around the
filters. The valve is equipped with a gauge to indicate
filter condition.
The secondary or engine mounted fuel filters are 13
micron elements located on the front left corner of the
diesel engine. As with the primary filters, these filters
are equipped with a bypass valve.
The bypass valve is located under a sight glass to
provide a visual indication of the plugged filters. Should
the filters begin to plug, the back pressure to the
primary filters will increase. When the pressure reaches
70 psi, the valve will open to divert the fuel flow. In this
case however, the fuel is returned directly to the fuel
tank instead of passing around the filters. As filter
condition worsens, more and more fuel is directed back
to the tank.
As fuel is diverted, engine performance decreases also.
If the filters become severly plugged, the engine will die
of fuel starvation, to avoid this kind of problem, the filters should be changed regularly.
From the secondary filters the fuel is diverted to the injectors by the fuel rails( supply fuel
manifolds) located inside the top deck area of the engine. Jumper lines connect each injector to the
fuel rail and fuel circulates freely through each injector before exiting out another jumper line to
the fuel return rail( return fuel manifold). The injectors use what fuel is necessary for engine
demands, the rest serves to cool and lubricate the injectors.
The fuel returning from the injectors passes through a return fuel check valve and return fuel sight
glass before returning to the fuel tank. The return fuel check holds a certain amount of pressure in
the engine to ensure proper injector operation. This valve is set for 15 psi. the return fuel sight glass
provides a visual indication of fuel system condition. If the system is operating properly, the sight
glass will be full of clean clear fuel. Air bubbles may indicate filter problem, suction leaks or faulty
injectors.

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Delivery
The delivery side of the system consists of the fuel injectors, the layshaft mechanism and the
control device or governor. The measuring and timing of the fuel must be carried out
simultaneously, or in the proper sequence and in the simplest manner by every fuel injection
system regardless of type.
 The fuel must be delivered by the injection mechanism
 The pressure of the fuel delivered by the injection mechanism must be sufficient to
overcome the pressure of compression
 The rate of fuel injection must be controlled
 The fuel must be broken up or atomized into fine particles
 The fuel must be properly distributed in the combustion chamber

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Mechanical Unit Injector
The unit injector system, shown in the figure is a development of the individual pump injection system.
Instead of as individual pump connected to an injection nozzle by a high pressure fuel line, the pump and
nozzle are combinedinasingle injectorunitwhichperformsall the injection functions. Eliminating the high
pressure fuel piping permits extremely high injection pressures - up to 20,000 or even 30,000 psi.
Each cylinder head carries a unit injector, which is actuated by a rocker arm from the camshaft. Within the
unitisa pumpplunger,whichraisesthe fuel pressure,metersthe charge and times the injection, a delivery
valve and a nozzle tip to give the desired spray pattern.

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Injector Operation
The unit injector, on being depressed by the rocker arm, takes fuel from the supply system and
meters, times, pressurizes and atomizes the fuel into the engine cylinder. The figure below
illustrates the operation of injector at approximately a half load position.
In the above figure, the plunger is at the top of its stroke. Note that both the upper and lower ports
are open and fuel is allowed to enter the chamber below the plunger. The plunger has a machined
recess called a helix. Fuel flows from the upper port into the helix, and through a drilled passage in
the plunger.
As the plunger begins to move down by the rocker arm, the lower port is blocked by the plunger.
Fuel is allowed to escape back through the drilled passage, helix, and upper port.
Next, the plunger has moved down far enough to close both ports. At this point, as the fuel is
trapped below the plunger, further downward movement of the plunger generates higher fuel
pressure. The pressure lifts the needle valve and injection begins.
As the plunger continues downwards, the lower port starts to open, allowing fuel to move up
through the drilled passage, escaping through the lower port, injection ends.
The plunger travel continues until the bottom of its stroke, however, the lower port is fully open
and no injection can take place.

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Injection control
The quantityof fuel injectediscontrolledbyrotatingthe plungerwith the rack. The amount of fuel injected
increases as the rack moves in. As the plunger rotates, the change in the helix in relation to the ports
changesthe effectivestroke length. The figure below illustratesthe effectiveinjectionstroke withthe rackin
different positions.
Position of the rack is set by the Woodward governor in response to engine speed requests. The
governor compares actual engine speed with desired speed and adjusts the fuel rate accordingly.
GM has made a significant contribution to the reduction of exhaust smoke and gaseous emissions
with the introduction of a new low smoke fuel injector. The key to the low smoke injector is the
new design low sac spray tip. The spray tip features a 53% reduction in the fuel sac below the
needle valve seat. Significantly less fuel remains below the needle valve after it has seated, thereby
reducing the potential after-dribble of fuel which causes smoke and undesirable emissions.

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Fuel System Troubleshooting
Before attempting to determine the cause of a fuel system problem, verify that there is fuel in the
fuel tank. Occasionally a struck or broken fuel level gauge will show fuel in the tank when it is
empty. Some of the common fuel system problems are given below:
Low Fuel or no Fuel pressure
 Ensure that the fuel pump breaker is in the on position and is not tripping out. With the
start switch in prime, verify that the pump and motor are both turning.
 Observe the 60 psi bypass sight glass, if fuel is present check to make sure the relief valve is
not struck open.
 Remove and clean the suction strainer and change all fuel filters.
 Visually examine all piping for leakage, restriction and partially closed valves
Internal Fuel Leaks
Fuel leaking inside of the engine can be detected by observing a high or rising engine lube oil level,
or by lube oil analysis. Large enough quantities of fuel will dilute the lube oil and reduce its
lubricating ability. Inspect the top deck area for leakage from injectors, top deck manifolds and
jumper lines, paying particular attention to jumper line seats on the injectors and the fuel manifold.
Do not stop looking after one leak is found, but continue until all cylinders have been checked.
If no leaks are found, it is possible that the injectors are leaking internally. Worn out or physically
damaged injectors can leak fuel into the cylinders, past the rings, and into the lube oil.
Bubbles in Return Fuel Sight Glass
The return fuel sight glass should be normally clear and free from bubbles when the engine is
running. Is the bubbles are observed, then shut down the engine, hold the engine start switch in full
prime position and observe the sight glass. If the bubbles stop the probable cause was an injector
tip leakage.
Fuel in bypass sight Glass
Normally the bypass sight glass is empty. Fuel in this sight glass indicates that the bypass relief is
open as a result of the back pressure caused by clogged engine mounted fuel filters. If fuel is still
present after changing the fuel filters, the relief valve should be inspected for a broken spring or
stuck plunger.
Intermittent fuel starvation
Foreign material in the fuel tank that is too large to go through the fuel suction line can block the
intake and cause starvation. When the engine is shut down, or expires from lack of fuel, the
material may be released when the suction from the fuel pump stops. When the engine is started

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again, it will run properly, until the material is picked up
again by the fuel pump suction. The fuel tank should be
drained to remove the objects, and if the problem continues,
the tank will have to be cleaned.
Locating a Misfiring Injector
Individual injectors can be checked for proper operation
while installed in the engine by two methods, the injector
pressure test and the clunk test.
 Clunk Test: With the engine at idle speed, remove
the spring clip and clevis pin from each injector
control lever one cylinder at a time. Slowly open the
rack by pulling outward on the injector control lever,
and then return it to idle position. If injector is
operating properly the cylinder will fire with a
pronounced clunk.
 Injector pressure test or pop test: A special tool is required to perform this test. Figure
illustrates it.

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Scheduled Maintenance
Daily or Trip
The fuel level should be checked frequently to ensure that the engine has an adequate supply for
operation. Running the engine frequently with a low fuel supply can lead to early filter failure due
to the buildup of condensation and other contaminants in the tank. It can also lead to early injector
failure since injectors rely on the fuel for cooling. A low fuel level will allow temperature to rise
dramatically. The fuel tank gauge is visually checked to ensure adequate fuel is present.
90 Day Inspection
At 90 days the primary fuel filters should be renewed. With the engine shut down, open the fuel
filter access doors. Remove the filter elements, thoroughly clean the tanks and renew the 2 paper
elements. Apply the new seals and secure the access doors. The secondary or spin on filters are also
renewed on the 90 day inspection. Both elements are pre-filled with clean fuel before applying to
the engine.
180 Day Inspection
On 180 day inspection, the suction strainer is removed and inspected for debris and contaminants.
3 Year Inspection
On the 3 year inspection, all fuel injectors are removed and replaced with new replacements.
6 Year Inspection
The 6 year inspection is the major inspection interval. Fuel pump and motor is removed and
reconditioned. The drive spider between the motor and pump is renewed. Fuel filters and injectors
are also inspected and replaced if required.

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Overhauling and Calibration of Mechanical Unit injectors
Overhauling refers to the process of making major repairs, renovations or revisions. Overhauling is
a very important process as it allows parts to be reused and ensures conservation of resources. The
process of overhauling of Mechanical Unit injectors is as follows:
 The injectors are first removed from the loco and dummy injectors are provided for the
cylinder head.
 The injectors are then cleaned externally using HSD.
 Next the injectors are opened and thoroughly cleaned with diesel and dry air. The injector is
next checked for the following parameters-
o Scoring on the plunger and barrel surface
o Seating surface of the spring cage
The process of overhauling may divided into the following stages-
 Stripping – the injector is disassembled and all parts are arranged properly
 Cleaning – all the components are cleaned with HSD
 Lapping – it involves polishing of all mating surfaces, after this the components are cleaned
in an ultrasonic cleaner
 Inspection – control rack teeth is to be checked for damage/bend, gear retainer and gear
are also to be inspected. After this the components are cleaned using diesel oil and all
components are immersed in injector calibration oil.
 Assembly – the injector is then assembled by replacing the body seal ‘o’ ring, copper
washers and filters.
Calibration
Calibration is a comparison between measurements – one of known magnitude or correctness
made or set with one device and another measurement made in as similar a way as possible with a
second device. It is an important process in overhauling an injector as it ensures that once the
injector is assembled after overhauling, the injector functions properly. The following are important
parameters for the injector –
 The valve opening pressure must be checked and recorded. It should be a maximum of 3400
psi.
 The injector nut should be tightened to a torque value of 120 lbs. and filler cap to 40 lbs.
 The freeness of the rack should be tested.
 The injector should be tested for leakage in leak off test; time for pressure drop 2000 psi to
1500 psi should be above 1 minute.
 The output of the injector is tested on the calibration stand, it should be around 332-344 cc.

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Bibliography
The above report has been prepared with the following references:
 ITS locomotive training Series – Student text
 Wikipedia.org
 Presentation on HHP Fuel oil System by Mr. S M Rahman