Diploma In Mechanical Engineering - Final Year Project

PROJECT REPORT ON
MAINTENANCE OF DIESEL AND PETROL ENGINE

SUBMITTED IN THE PARTIAL FULFILLMENT OF THE REQUIREMENT
FOR THE AWARD OF DIPLOMA
IN
MECHANICAL ENGINEERING
FROM
GOVERNMENT POLYTECHNIC KANGRA

UNDER THE SUPERVISION OF
ER. D.R. SHARMA
(H.O.D MECHANICAL ENGINEERING)
SUBMITTED BY

S.No.	Name	S. No.	Name
1.	Pankaj	7.	Rohit
2.	Punnet	8.	Sajan Lakhanpal
3.	Rajat Dhiman	9.	Santosh
4.	Rajnesh Kumar	10.	Shantanu Rana
5.	Reshav	11.	Shubham Awasthi
6.	Robin Bhardwaj	12.	Shubham Chaudhary

GOVT. POLYTECHNIC KANGRA
(AS ISO 9001 : 2008 CERTIFIED INSTITUTE)

DEPARTMENT OF MECHANICAL ENGINEERING

CERTIFICATE

            Certified that the project entitled “MAINTENANCE OF DIESEL AND PETROL ENGINE” submitted by Pankaj Dheer, Punnet, Rajat Dhiman, Rajneesh Kumar, Reshav, Robin Bhardwaj, Rohit, Sajan Lakhanpal, Santosh Kumar, Shantanu Rana, Shubham Awasthi, Shubham Chaudhary in the partial fulfilment of the requirement for the award of DIPLOMA in MECHANICAL ENGINEERING of HIMACHAL PRADESH TAKNIKI SHIKSHA BOARD DARI, DHARAMSHALA is record of student’s practice work carried out under our supervision and guidance. It is further understood that by this certificate the undersigned do not endorse or approve any statement made, opinion expressed or conclusion drawn there in but approve the report only for the purpose for which it is submitted.

Supervisor	Head of Department
Er. D.R. Sharma	Er. D.R. Sharma
Er. Parul Dhiman

ACKNOWLEDGEMENT

No volumes of words are enough to express our gratitude toward our guides Er. PARUL DHIMAN, LECTURER in Department of Mechanical Engineering, Government Polytechnic Kangra who have been very concerned and have guided for all the ideas and solved our quires in the preparation of this project. They have been very co – operative and sincere to guide us through to see our hard works become fruitful.

                        We are thankful to ER. D.R. SHARMA, Head of Department, Mechanical Engineering, Government Polytechnic, Kangra and also our project coordinator, for giving us the opportunity to carry out this project.

                        Most importantly we would like to thank almighty for showing use the right path, to help us stay calm in the oddest of the time and keep moving even the times when there was no hope.

                        Lastly we thank our friends and persons who were involved directly or indirectly and spared time to cite valuable suggestions without which this work would not have casted in to present form.

TABLE OF CONTENTS
S.NO.	DESCRIPTION	PAGE NO.
1.	Certificate	2
2.	Acknowledge	3
3.	Introduction (Diesel Engine)	5
4.	Objective And Aim	7
5.	Specification of Diesel Engine	8
6.	Various Parts of Diesel Engine	9
7.	Dismantling Procedure (Diesel Engine)	14
8.	Common fault and solution of Diesel Engine	15
9.	How to Diagnose Fuel Injector Problem	18
10.	Maintenance of Petrol Engine	23
11.	Technical Specification (Petrol Engine)	24
12.	Tool and Equipment Used	25
13.	Dismantling Procedure  (Petrol Engine)	26
14.	Main Parts (Petrol Engine)	27
15.	Common Faults (Petrol Engine)	29
16.	How to Diagnose Carburetor Problem	30
17.	Symptoms of bad or failing spark plug	33
18.	Symptoms of bad or failing distributor rotar and cap	36
19.	Proper Firing order of a 4 Cylinder Petrol Engine	38
20.	Cost Estimation	39
21.	Conclusion	41
22.	Reference	42

INTRODUCTION (DIESEL ENGINE)

The diesel engine (also known as a compression-ignition or CI engine) is an internal combustion engine in which ignition of the fuel that has been injected into the combustion chamber is caused by the high temperature which a gas achieves (i.e. the air) when greatly compressed (adiabatic compression). Diesel engines work by compressing only the air. This increases the air temperature inside the cylinder to such a high degree that it ignites atomized diesel fuel that is injected into the combustion chamber. This contrasts with spark-ignition engines such as a petrol engine (gasoline engine) or gas engine (using a gaseous fuel as opposed to petrol), which use a spark plug to ignite an air-fuel mixture. In diesel engines, glow plugs (combustion chamber pre-warmers) may be used to aid starting in cold weather, or when the engine uses a lower compression-ratio, or both. The original diesel engine operates on the "constant pressure" cycle of gradual combustion and produces no audible knock.

            The diesel engine has the highest thermal efficiency (engine efficiency) of any practical internal or external combustion engine due to its very high expansion ratio and inherent lean burn which enables heat dissipation by the excess air. A small efficiency loss is also avoided compared to two-stroke non-direct-injection gasoline engines since unburned fuel is not present at valve overlap and therefore no fuel goes directly from the intake/injection to the exhaust. Low-speed diesel engines (as used in ships and other applications where overall engine weight is relatively unimportant) can have a thermal efficiency that exceeds 50%.

            Diesel engines may be designed as either two-stroke or four-stroke cycles. They were originally used as a more efficient replacement for stationary steam engines. Since the 1910s they have been used in submarines and ships. Use in locomotives, trucks, heavy equipment and electricity generation plants followed later. In the 1930s, they slowly began to be used in a few automobiles. Since the 1970s, the use of diesel engines in larger on-road and off-road vehicles in the US increased. According to the British Society of Motor Manufacturing and Traders, the EU average for diesel cars accounts for 50% of the total sold, including 70% in France and 38% in the UK.

            The world's largest Diesel engine put in service in 2006 is currently a Wärtsilä-Sulzer RTA96-C Common Rail marine diesel, which produces a peak power output of 84.42 MW (113,210 hp) at 102 rpm.

OBJECTIVE AND AIM

OBJECTIVE:

To learn the proper technique of dismantling a single cylinder diesel engine to study the function, material and serviceability of each part. Reassembly of serviceable parts for proper function of the engine.

GENERAL AIM:

Ø develop logical processes of faultfinding

Ø learn the correct use and care of the tools and equipment associated with this module

Ø be familiar with the function of the various components associated with diesel engines

Ø develop safe working practices and be aware of the hazards of their workplace or location

Ø perform a range of maintenance procedures associated with diesel engines

SPECIFICATIONS OF DIESEL ENGINE

Technical Specifications for high speed air cooled Single cylinder diesel Engine (OMA -2)

Rating	4 – 8 KW/6.5 HP)
Governing	Class – BI
Fuel	H.S. DIESEL
Type	OMA – 2
R.P.M	1500
SFC.	252g./kwh.
LUB. Oil	SAE 30/40
Manufacture	OPEX Engineering Corporation – Pahgwara

VARIOUS PARTS OF DIESEL ENGINE (OMA -2)

Ø CYLINDER BLOCK: Cylinder block or Cylinder are main part of an engine. It is a part in which combustion of fuel takes place. All other parts like piston, connecting rod, crankshaft, water jacket etc. are bolted on it.

Ø  PISTON: Piston is placed in the cylinder and transmits thrust to the connecting rod. It is free to move. It compresses the air fuel mixture and convert the fuel energy into mechanical energy. It transmits the power to the crankshaft.

Ø CYLINDER HEAD: Cylinder head is fitted on the top of cylinder block and the function of the cylinder head is to seal the working end of cylinder and not to permit entry and exit of gases on cover head valves of the engine. The valves, spark plug, camshaft etc. are fitted on it.

Ø CONNECTING RODS: It connect piston to the crank shaft and transmit the motion and thrust of piston to crank shaft. The lower end of connecting rod is connected to the piston and the bigger is connected to the crank shaft.

Ø  CRANKSHAFT: It is located in the bottom end of cylinder block. It transmits the reciprocating motion of piston into rotary motion. This rotary motion used to rotate wheels of the vehicle.

Ø CAM SHAFT: It is fitted either in the cylinder head or at the bottom of the cylinder block. It is use to open or close valves at proper timing in multi-cylinder engine.

Ø VALVES: It is fitted on the cylinder head. It regulates the flow of air fuel mixture inside the cylinder and exhaust gas outside the cylinder block.

When both inlet and exhaust valves are closed no pressure can go inside or outside of cylinder block.

Ø INJECTOR: It is used in Diesel engine (Compression Ignition Engine). It is fitted on the cylinder head. It is used to inject fuel in spray form inside the cylinder at the end of compression stroke.

Ø PUSH ROD: It is used when the camshaft is situated in the bottom of the cylinder head.

It regulates the timing of valves open and close through rocker arm and camshaft.

Ø MANIFOLD: It is bolted on the cylinder head one each for intake and exhaust. Its function is to evenly distribute air-fuel mixture for intake & collects the exhaust gases from all cylinders.

Ø PISTON RINGS: It provides the good sealing fit and less friction resistance between piston and cylinder. It is split at one point so it can be easily installed into the grooves cut in the piston.

Ø ENGINE BEARING: Bearings are used to support the moving parts. The purpose of bearings is to reduce friction. The crankshaft is supported by bearing. In engine two types of bearing are used sliding bearing and rolling bearing.

DISMANTLING PROCEDURE:

Ø Drain oil from the sump.

Ø Remove the rocker box and rocker assembly.

Ø Remove the push rods.

Ø Remove the air cleaner and silencer along with elbow pipes from the cylinder head. Disconnect the high pressure line to the injector and take out injector.

Ø Remove the inlet valve, exhaust valve, valve springs and valve cotters.

Ø Remove the side cover and loosen the big end of the connecting rod and take out the piston along with connecting rod.

Ø Use ring expander to remove the oil and compression rings.

Ø Remove the circlips from the piston using circlip plier. Push out the gudgeon pin and separate the connecting rod from the piston.

Ø Remove the cylinder block.

Ø Remove the timing cover and take out camshaft and crankshaft gears.

Ø Remove the fuel injection pump.

Ø Remove the side cover of the fuel injection pump.

Ø While removing the cam shaft, make sure that tappet rollers for inlet valve, exhaust valve and fuel injection pump do not fall in the sump.

Ø Remove the fly wheel with puller.

Ø Remove the front and rear covers housing ball bearing for the journals.

Ø Remove the oil filter and plunger type oil pump and take out the crank shaft from the crank case. Thus the engine parts are almost dismantled. Clean all the parts for review to replace or service for assembly.

Common Faults and Solutions of Diesel Engine

DIESEL ENGINE CANNOT START SEVERAL REASONS

Prerequisite for normal diesel engine operation is atomized diesel accurate and timely sprayed into the combustion chamber and the combustion chamber of compressed air to reach a sufficient temperature in order to fire outbreak. To meet these two conditions, it must have a high enough speed and a certain temperature within the cylinder diesel engine starting. Diesel engine cannot start from the start of work, look for the causes of diesel engine fuel supply system and compression.

·     The ambient temperature is too low. In the case of low temperatures, the engine warm-up should be prepared, otherwise difficult to start.

·     Starting speed. Hand start diesel engine, you should gradually increase the speed, and then pull the decompression lever to the non-decompression position, so that normal compression cylinder. If the decompression agency improperly adjusted or valve withstood piston, tend to feel the shaking car is very laborious. Which is characterized by the crankshaft to go to a site on the turn no more, but it can be returned to. At this point, in addition to check the decompression institutions should also check the timing gear meshing relationship wrong.

EXHAUST BLACK SMOKE FOR THE FOLLOWING REASONS:

·        Uneven pressure fuel supply to the excessive or cylinder fuel supply

·        Valve sealing leakage, resulting in leakage, low cylinder compression pressure

·        Air filter inlet obstruction, resistance of the inlet into the gas

·        Cylinder, piston, piston rings severe wear

·        Injector bad work

·         Engine overload

·        The fuel injection pump fuel delivery advance angle is too small, the combustion process to the exhaust process

·        Gasoline fuel injection system control failure

The black smoke of the engine through the high pressure oil pump adjustment, fuel injector spray test to check the cylinder compression pressure measurement, inlet cleaning, fuel supply advance angle adjustment, gasoline fuel injection system failure diagnostic work to be inspected and excluded.

KNOCKING SOUND

Knock, refers to a piston working stroke of the moment, or piston row, issued by the piston in the cylinder of the swing, the head and skirt and cylinder wall collision "Dangdang" or "blah" abnormal sound. "Blah" sound, the exhaust pipe to take the blue smoke, generally due to the piston and cylinder wall clearance is too big reason. The main reason for these are the following:

·    If only after the cold start of this phenomenon. Running up to the normal water temperature when away on its own, because the piston and cylinder wall with the gap is too large, cold car piston another contraction, both with the gap is further increased, thereby percussion. Machine temperature rise after the piston expansion, the gap tends to normal, it is abnormal sound disappeared. This case no major problems in the short term.

·    Oil grade and requirements does not match the engine flameout a long time, started again, the oil viscosity, poor liquidity, the short period of time the cylinder wall cannot form a good film, piston and cylinder wall, directly resulting from collisions knock. In operation for some time, the lubricating oil viscosity is normal, the formation of a layer of film on the cylinder wall, abnormal sound is diminished or disappeared. Reasonable selection of lubricants, to warm up before starting the engine crankcase, mixed with oil lubrication, before the start of multi-step a few times to start the rod, so that mechanical adhesion more lubricants, such a situation that is, can be avoided.

·    Gas mixture in the cylinder cannot be normal combustion, resulting in the moment of early burning or deflagration, or engine no load fierce fuel door, will produce the sound of crashing by the piston and cylinder wall. Should keep the engine at normal temperature, to meet the octane requirements for gasoline, and appropriate adjustments to ignition timing.

·    the piston skirt wear, cylindricity error is too large, the piston line, the top will hit the cylinder walls, pistons and cylinder serious wear and tear, the gap between the two?? Wall. The biodegradable check, under the circumstances to take the appropriate repair measures.

·     due to rod bending and torsion, piston pin and the pin hole deflection, crank pins and piston pin two axis lines not parallel, will cause the piston in the cylinder skew run and hit the cylinder wall. This situation can only decompose to check and replace the corresponding parts in the diagnosis.

HOW TO DIAGNOSE FUEL INJECTOR PROBLEMS

Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector.

All diesel engines use fuel injection by design. Petrol engines can use gasoline direct injection, where the fuel is directly delivered into the combustion chamber, or indirect injection where the fuel is mixed with air before the intake stroke.

UNDERSTAND FUEL INJECTORS

Before setting to work diagnosing fuel injector problems, it helps to understand what fuel injectors are. This section describes the basic process of how a fuel injection system works and the role that fuel injectors play in this process.

FUEL INJECTION SYSTEM BASICS

A car's engine uses an internal combustion process to generate power, with the two key ingredients to this process being oxygen and fuel. The engine takes oxygen from the air surrounding it and fuel from the reservoir that holds the car's gasoline. An air intake system delivers the air to the engine and a fuel injection system delivers the gasoline. The engine's gas supply is limited, so in order to use it efficiently the engine must apply the right amount of gasoline to mix with the oxygen that it is receiving. Since the oxygen supply fluctuates, the fuel injection system must constantly change the amount of gasoline that it delivers, and it must deliver the gasoline in a precise manner so as not to waste any of it.

THE ROLE OF FUEL INJECTORS

Fuel injectors play a very important role in the engine's fuel delivery system in that they deliver the exact amount of gasoline that the engine needs, even as the requirements shift quickly and constantly. An injector is a valve with electronic controls that receives signals from the engine control unit. A gas pump delivers pressurized gasoline into the fuel injectors and the engine control unit tells the fuel injectors to open a valve to let the pressurized gas pass through an atomizing nozzle. The fuel injectors thereby spray a fine gasoline mist into the engine's intake manifold, which then delivers it to the engine for combustion with the oxygen that the engine is receiving. This mist makes for more efficient burning of the gas in combustion than if it were in droplet form. The more gasoline that the engine requests, the longer the valves in the fuel injectors stay open. Pulse width describes the amount of time that the valves stay open.

BECOMING FAMILIAR WITH COMMON FUEL INJECTOR PROBLEMS AND THEIR SYMPTOMS

This section describes the problems and symptoms that are related to fuel injector problems. It is important for readers to be familiar with these problems and symptoms if they plan to diagnose the fuel injectors on their own, as this will help them to accurately diagnose problems.

COMMON PROBLEMS

This section lists the most common problems that are associated with fuel injectors. Some problems are easy to correct, while others require replacement of the fuel injectors.

Dirty Fuel Injectors

Fuel additives that do not spray into the intake manifold can leave a residue on the fuel injectors. These can burn and form a crust because fuel injectors run very hot due to the friction that is produced from rapid and repetitive movement. The crust on the fuel injectors can result in a weak spray and an uneven pattern.

Clogged Fuel Injectors

Fuel injectors can also clog from the buildup of microscopic foreign objects, which are usually in the form of rust. This is typically introduced from a source upstream in the gasoline supply, such as the fuel supply line or the fuel rail, and it can result from a car sitting idle without maintenance for a long time. A clogged fuel injector will not be able to supply gasoline to the intake manifold.

Fuel Injector Does Not Open

The valve in the fuel injector might not open as the result of faulty windings or as the result of a rusted fuel injector. The windings might overheat, short out, or break, and rust can cause the valve to stick. In any of these instances, the valve will not open and the fuel injector will be unable to deliver gasoline through its nozzle.

Fuel Injector Does Not Close

The valve in the fuel injector might also be unable to close due to a faulty spring or due to a buildup of rust or fuel additives. If the valve is unable to close properly, the fuel injector will leak gasoline.

Fuel Injector Leaks

The fuel injector may also leak gasoline if other parts of the system fail, such as the mechanism that cools the injector. The fuel injector can then overheat and fail, resulting in a leak. It is also possible that the injector has a faulty part that does not enable it to function properly.

Symptoms That Can Signify a Problem

The table below describes the various symptoms that can signify a possible problem with fuel injectors. It also associates the problems detailed above with these symptoms.

Symptom	Description	Associated Problems
Inconsistent Engine Power	An inconsistent fuel supply can cause the engine to rev high and low, with the RPM gauge fluctuating.	Dirty fuel injector
Misfiring Engine	When the fuel supply is inadequate upon ignition, the engine might misfire. An 8 to 10 percent reduction in one fuel injector can cause this to occur.	Dirty fuel injector Clogged fuel injector Fuel injector does not open
Uneven Engine Idling	An engine should idle smoothly, but an uneven fuel supply will cause idling disturbances.	Dirty fuel injector
Fuel Scent	Leaking fuel from a faulty fuel injector will create a strong gasoline smell.	Fuel injector does not close Fuel injector leaks
Diminished Gas Mileage	A fuel injector that delivers drops of gasoline instead of a mist will make for inefficient use of the gas, reducing the car's gas mileage.	Fuel injector does not close Fuel injector leaks

Being able to observe these symptoms is an important aspect of realizing that there is a problem with a car, and being able to associate these symptoms with specific fuel injector problems will help car owners to resolve the issues with their injectors quickly.

RUN DIAGNOSTIC TESTS

This section describes a few tests that owners can run to help them to diagnose fuel injector problems. These tests are relatively simple, though they do require accessories to complete them.

·         Measure Exhaust Manifold Temperatures

If a fuel injector will not close, it will dump gasoline on the catalyst that opens and closes the valve, causing it to overheat and burn out. This will produce high temperatures at the exhaust manifold while the engine is warm. If the valve will not open, an excessive amount of oxygen will disable the catalyst, producing excessively low temperatures at the exhaust manifold. To determine whether this is an issue, point a laser thermometer at the pipes of the exhaust manifold while the engine is warm. A normal reading on each cylinder will be within 30 degrees of 450 degrees Fahrenheit. An injector that will not open will yield a temperature of 200 to 250 degrees and an injector that will not close will show temperatures of 600 degrees or more.

·         Listen to the Fuel Injectors

Another helpful diagnostic tool is an engine stethoscope. This tool enables a car owner to listen for any problems with the fuel injectors by placing the tip of the stethoscope on each injector. Fuel injectors make a sharp clicking sound when they are functioning properly, so the absence of this sound can indicate a problem with an injector.

 

·        Inspect the Fuel Injectors

A third way that car owners can diagnose their cars' fuel injectors at home is by removing the fuel injectors and inspecting them. Start by detaching the fuel rails to which the injectors are likely attached. After removing the rails, detach each fuel injector from each rail. Fuel will flow from the rails as each injector is removed, so be sure to wear gloves during this process. After removing all of the fuel injectors, inspect each one for signs of cracks or damage to any of the parts within the injectors.

MAINTENANCE OF PETROL ENGINE

A petrol engine (known as a gasoline engine in American English) is an internal combustion engine with spark-ignition, designed to run on petrol (gasoline) and similar volatile fuels.

In most petrol engines, the fuel and air are usually pre-mixed before compression (although some modern petrol engines now use cylinder-direct petrol injection). The pre-mixing was formerly done in a carburetor, but now it is done by electronically controlled fuel injection, except in small engines where the cost/complication of electronics does not justify the added engine efficiency. The process differs from a diesel engine in the method of mixing the fuel and air, and in using spark plugs to initiate the combustion process. In a diesel engine, only air is compressed (and therefore heated), and the fuel is injected into very hot air at the end of the compression stroke, and self-ignites.

TECHNICAL SPECIFICATIONS

TYPE	4 CYLINDER, VERTICAL, INLINE
BORE X STROKE IN MM	78  X 17.5
TOTAL DISPLACEMENT	1366 CC
MAX POWER (GROSS)	43.4@ 4600 RPM (AS PER SAE-J-1391)
MAX TORQUE (GROSS)	7 KG.MK. @ 2800 RPM (AS PER SAE – J – 1391)

TOOLS AND EQUIPMENT:

·       A kit of tools consisting socket

·       Spanner Set

·       Ring Spanners

·       Double ended spanners

·       Spark Plug Spanners

·       Feller Gauge

·       Combination Plier

·       Nose Plier

·       Circlip plier

·       Piston ring clamp

·       Bearing puller

·       Screw Driver

·       Mallet

·       Steel Tray

·       Brush

·       Diesel Oil

·       Cotton waster

·       Clean rags

·       Lubricating oil

·       Grease etc.

DISMANTLING PROCEDURE:

·        Drain oil from the gear box.

·        Remove the carburetor and put it in a clean tray.

·        Loosen the spark plug with the spark plug spanner and keep it aside.

·        Remove the cylinder head and cylinder block.

·        Remove the magnet assembly with a special puller.

·        Remove the clutch assembly.

·        Remove the gear shifter.

·        Remove the crankcase bolts, to have access to the crankshaft, connecting rod and piston.

·        Remove the circlips of the gudgeon pin and separate the piston from the connecting rod small end.

·        Remove the compression rings using ring expander.

·        Remove the crank shaft bearing with the puller and remove the connecting rod.

MAIN PARTS

S.No.	Name of Part	Function	Material
1.	Cylinder Head	It is a cover for closing one end of cylinder and accommodates the spark plug.	Aluminum Alloy
2.	Cylinder	It acts as an enclosure for the air fuel mixture for compression and ignition, to liberate heat form mechanical energy.	Aluminum Alloy
3.	Piston	It is the reciprocating part in the cylinder to suck, compress and exhaust the charge and converts pressure energy of the ignited charge into mechanical energy of the crankcase.	Aluminum Alloy
4.	Piston Rings	These prevent the leakage past the piston and cylinder wall.	Cast Iron
5.	Gudgeon pin	It acts an inter link between piston and small end of connecting rod.	Case Hardened steel or Alloy Steel
6.	Connecting Rod	It acts an inter link between piston and crankshaft to transmit the mechanical energy of the piston to the crankshaft.	Alloy Steel
7.	Crankshaft	It converts the reciprocating motion of the piston received by the connecting rod into rotary motion.	Alloy Steel
8.	Flywheel cum Fan	It provides energy to the piston to perform power consuming operations i.e. suction, compression and exhaust.	Aluminum Alloy
9.	Main Bearings	These act as a support for the crankshaft between the crankshaft and the crank case by providing needle bearing or ball bearing.	Steel
10.	Spark Plug	It ignites the compressed charge of air fuel mixture with the help of spark produced between the electrodes.	Central electrode enclose with porcelain insulation and steel body.
11.	Ignition System	It consists of magnet assembly having primary coil, secondary coil, CB Points, ignition coil and permanent magnet to produce the high tension current to ignite the mixture of air fuel.	Steel magnet copper winding of coils with aluminum condenser
12.	Carburetor	It is a device to mix air and fuel in proper ratio and supply to the cylinder at proper time.	Aluminum body gun metal
13	Air Cleaner	It removes dust and dirt from the incoming air.	Jets Perorated paper
14.	Gear Box	It consists of clutch assembly shaft, main shaft and cluster assembly for power transmission to the wheel.	Steel

COMMON FAULTS IN PETROL ENGINE

ENGINE DOES NOT START: It may be due to:

·        Discharged battery

·        Cracked distributor cap

·        Pitted and dirty contact breaker points

·        Insufficient gap of contact breaker

Rapidly burning of the breaker points: It may be due to:

·        Condenser not earthed properly

·        Condenser defective

·        Oily breaker points

·        Points gap too small

·        Weak breaker arm spring

·        Excessive generator voltage

SPARK PLUG FAILURE: It may be due to:

·        Incorrect plug – gap

·        Poor ignition and too much carbon deposited in the plug.

·        Burned plug electrodes

·        Plug produces poor spark

ENGINE MISFIRES AT HIGH SPEEDS: It may be due to:

·        Coil or condenser defective

·        Point gap too little

·        Worn – out breaker plate assembly

·        Breaker points bounce

HOW TO DIAGNOSE CARBURETOR PROBLEMS

Before attempting to fix a carburetor problem, it is very important to come up with the correct diagnosis.

Carburetors are relatively simple devices. Their primary function is to deliver the correct amount of fuel/air mixture at a given throttle opening (as selected by the rider). However, as with all mechanical devices, carburetors will wear over time and will also require periodic tuning and service.

Carburetor problems generally fall into three areas: rich mixture, lean mixture, and incorrect adjustment. Diagnosing carburetor problems is relatively easy and follows some telltale symptoms.

THREE CARBURETOR PROBLEMS

v ​RICH MIXTURE means the carburetor is delivering too much gasoline. Typical symptoms of a rich mixture are:

Ø Poor fuel economy

Ø Sluggish acceleration

Ø Choke not needed from cold starts

Ø Sooty or black spark plugs

Ø Sooty or black muffler end pipes

Ø Strong smell of gasoline when machine is at idle

Ø Uneven running (will often slow from regular idle rpm's and stop)

v LEAN MIXTURES means the carburetor is delivering too much air. Typical symptoms of a lean mixture are:

Ø Backfires as the throttle is closed (primarily during coast-downs)

Ø Lurching acceleration

Ø White or light grey spark plugs

Ø Requires excessive amounts of choke to run/start

Ø White or light grey muffler end pipes

Ø Bluing (on chrome systems) of the exhaust header down-pipes

v INCORRECT ADJUSTMENT applies to carburetors that have incorrect adjustment of the air/fuel screw and the balance between two or more carburetors - where fitted. Incorrect adjustment can produce any of the previously noted symptoms. On multi-cylinder machines, with separate carburetors for each cylinder, the following symptoms are typical of an adjustment problem:

Ø Poor overall performance

Ø Rattling sounds from the clutch

Ø Engine tends to stall easily

Ø Erratic acceleration

Ø Poor fuel economy

Ø Misfires and/or backfires

CORRECTING CARBURETOR PROBLEMS

LEAN MIXTURES: This condition is generally caused by the owner fitting after-market accessories such as exhaust systems, air filter systems or replacement carburetors of a different type or size. In addition, if the fuel level in the float chamber is set too low, insufficient fuel will be drawn through the main jet. Some carburetors have a slow speed fuel adjusting screw that regulates the fuel/air mixture in the lower rpm range.

RICH MIXTURES: This condition is primarily caused by dirty air filters, but it could also result from the owner fitting replacement exhausts and/or carburetor systems. If the fuel level is set too high in the float chamber, a rich mixture will result.

Incorrect Carburetor Adjustment: This situation is mostly caused by poor maintenance. With the inherent vibration of all engines, carburetor parts (primarily adjusting screws) tend to rotate, and therefore change their positions. Low-speed running jets and multi-cylinder balancing screws are the items most prone to self-adjust during normal operation and often require periodic corrections.

SYMPTOMS OF BAD OR FAILING SPARK PLUGS

Common signs of faulty spark plugs include slow acceleration, loss of power, poor fuel economy, engine misfires, and difficulty starting the car.

Without a spark, there would be no way for fuel to ignite in the combustion chamber. Spark plugs have been a critical component of the internal combustion engine for years. Spark plugs are designed to transmit an electrical signal sent from the ignition coil at a predetermined time to create a spark that ignites the air-fuel mixture inside the combustion chamber. Each vehicle requires a particular type of spark plug made from specific materials and with a designated spark plug gap that is set by a mechanic during installation. Good spark plugs will burn fuel efficiently, while bad or failing spark plugs can cause the motor not to start at all.

v SLOW ACCELERATION

The most common cause of poor acceleration on most vehicles is a problem in the ignition system. Today's modern engines have multiple sensors that tell the onboard computer and ignition system when to send electric pulses to fire the spark plug, so the issue may be with a faulty sensor. However, sometimes the issue is just as simple as a worn out spark plug. A spark plug is composed of materials that work together in order to produce a spark hot enough to ignite the air-fuel mixture. When those materials wear out, the effectiveness of the spark plug is reduced, which can significantly reduce the acceleration of the vehicle. If you notice that your car is running sluggishly or does not accelerate as quickly as it used to, it may be attributed to a spark plug that needs to be replaced.

v POOR FUEL ECONOMY

When a spark plug works correctly, it helps burn fuel efficiently in the combustion cycle. When this occurs, your car can achieve better than average fuel economy. When the plug is not functioning optimally, it is frequently due to the fact that the gap between the spark plug electrodes is either too close or too far apart. In fact, many mechanics will take out spark plugs, examine them, and adjust the gap to factory settings as opposed to replacing the spark plug entirely. If your vehicle has a reduction in fuel economy, it very well could be attributed to a worn out spark plug.

v ENGINE IS MISFIRING

If the engine misfires, it's typically due to an issue in the ignition system. Most of the time in modern cars it's due to a sensor malfunction. However, it may also be caused by a spark plug wire or the tip of the spark plug that connects to the wire being damaged. An engine misfire can be noticed by intermittent stumbling or sputtering sounds from the engine. If the engine is allowed to keep misfiring, exhaust emissions will increase, engine power will decrease, and fuel economy will drop. Because of all the potential problems associated with engine misfiring issues, you should contact a mechanic as soon as you notice an engine misfire.

v DIFFICULTY STARTING THE VEHICLE

If you have trouble starting your vehicle, it could be a sign your spark plugs are worn. However as noted above, the engine's ignition system is comprised of multiple individual components that must work cohesively in order to function properly. At the first sign of problems starting your car, truck or SUV, it's a good idea to contact a certified mechanic to take a look at the cause.

Regardless of what the issue might be, the reality is that spark plugs will eventually wear out. Being proactive about spark plug maintenance can extend the life of your engine by hundreds of thousands of miles.

SYMPTOMS OF A BAD OR FAILING DISTRIBUTOR ROTOR AND CAP

Common signs include engine misfires, car not starting, the Check Engine Light coming on, and excessive or unusual engine noises.

A running engine sends a large amount of electricity through the ignition coils to the rotor, which turns inside the distributor. The rotor routes the energy in a specific through the spark plug wires ultimately to the engine’s cylinders in the correct firing order.

The distributor rotor and cap keep the distributor’s contents separate from the engine and keep the distributor’s working parts clean and tidy – while supporting the incredibly high volts of energy and delivering them to the appropriate spark plugs. The spark plugs utilize the spark from the distributor to ignite the fuel mixture, which is what keeps the engine running.

High voltage runs through this entire distributor system during the operation of your vehicle, but if there's an issue this voltage won’t get distributed to the correct spark plugs to ensure that your engine will run. Usually a faulty distributor rotor and cap will produce a few symptoms that alert the driver that service may be required.

v ENGINE MISFIRES

Engine misfires can occur for a number of reasons. Checking your distributor rotor and cap to see if they need to be replaced is one way to ensure that everything is in solid working order.

v CAR DOESN’T START

When the distributor cap isn’t on tightly or is malfunctioning, the engine is unable to send the spark through the entire circuit required to move the cylinders – which ultimately make the car run.

v EXCESSIVE OR UNUSUAL ENGINE NOISES

Your vehicle may make some very strange noises if the distributor rotor and cap are malfunctioning – specifically because the cylinders will try to fire but fail. You might hear a tapping, clicking, or sputtering sound when the distributor rotor and cap are failing.

Any time you have routine service performed on your vehicle, ask that the ignition system be checked for defects or problems.

PROPER FIRING ORDER OF A 4 CYLINDER ENGINE

The typical firing order of Inline four cylinder engine is 1-3-4-2. Firing order in a multi-cylinder engine is arranged so that the torsional moment is even and the load is uniformly distributed on longitudinal direction of the crankshaft. An even firing order will increase the balance of engine.

A 4-stroke engine completes four strokes while crankshaft rotates 2 times. For a four cylinder engine hence an even firing should happen every 180 degree rotation of crank.

The following principle should be considered, in spacing out the firing

·        The combustion should not occur simultaneously in two or more cylinders;

·        Successive combustion in the cylinders that standing side by side should be avoided so that the force transmitted to the crankshaft does not become one-sided.

COST ESTIMATION

Diesel Engine
Sr. No.	Component Name	Cost (INR)
1.	Diesel	150
2.	Injector	50
3.	Oil Pump	100
4.	Fuel Pipe	50
5.	Rocker Box	380
6.	Diesel Filter	225
7.	Gaskets	20
8.	Injector Washer	5
10.	Exhaust Elbow	70
11.	Oil Paint Varnish	40
12.	Thread	10
13.	Flexible Exhaust Pipe	150
14.	M-seal	20
	Total	₹1270

	PETROL ENGINE
Sr. No.	Component Name	Cost (INR)
1.	Petrol	250
2.	Spark Plug	200
3.	Plug Cap	80
4.	Battery Water	30
5.	Air Filter	10
6.	Engine Oil (3.5L)	700
7.	Battery Terminals	60
8.	Petrol Oil Filter Service	50
9.	Self-Start	400
10.	PVC Tape	10
11.	Clamps for cooling	75
12.	Professional Help	900
13.	Gear Oil (3L)	670
	Total	₹3435

	Transportation Cost	₹300

	General Utilizing Material
Sr. No.	Item	Cost (INR)
1.	Soap	20
2.	Fevi Quick	20
3.	Electrodes	30
	Total	₹70

	Total Cost
1.	Diesel Engine	1270
2.	Petrol Engine	3435
3.	Transportation Cost	300
4.	General Utilizing Material	70
	Total	₹5075

CONCLUSION

Our project “Maintenance of Diesel and Petrol Engine” has been successfully completed.  The deep maintenance project brought together resources from every corner to participate in some way however large or small. This in itself could be seen as the greatest success factor in the project. Every person who participated in the project gained valuable knowledge on the issue of diesel and Petrol engine maintenance that so many continue to believe to be a non-issue. At the end of the project it is clear to all of us who participated that improved maintenance practices on diesel engines is the first line of control to reductions in emissions. To simply re-state the objectives of the project and how the work has achieved success on each point would be further repetition of what would by now be obvious. The final judgement should be left to those who actually did the work with this project and continue to carry on with the monitoring of emissions and practicing improved engine maintenance long after the project has been completed. During the case studies in the project the mechanics were asked to provide feedback as to their thoughts on the new maintenance practices and the future.

REFERENCES

The Project Idea
Project Queries	Er. Parul Dhiman

Others:

·        www.google.com

·        www.mechprix.com

·        www.wikipedia.com

·        Encyclopedia

·        V. Ganeshan (2007). Internal Combustion Engines. New Delhi: The Mc Graw Hill

·        Willard W. Pulkrabeck. Engineering Fundamental Of The Internal Combustion Engines. New Jersey: Prentice Hall.

·        John B. Heywood (1998). Internal Combustion Engine Fundamentals. The Mc Graw Hill Series.