automotive technology assignment

7/31/2019 Automotive Technology Assignment

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Automotive Technology Assignment#1

The Schematic Diagram, Parts and Functions of the Fuel, Exhaust, Lubrication,

Cooling, Charging and Ignition System

Submitted By:

Prince Leonard R. Vergara

8:30-9:30, TTHS

Submitted to:

Engr. Doniam Jose M. Billote


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I. Fuel System

The Engine Fuel System Components

Fuel TankAs the name would indicate, a fuel tank is a container that stores a vehicle's fuel.

Fuel tanks have a filler tube with an opening on the side of the vehicle for adding fuel to the

tank. The tank also has an electronic "trigger" that relays information to the gas gauge

regarding the amount of fuel in the tank.

Fuel PumpModern automobiles have a fuel pump attached directly to or inside the fuel tank.

Older vehicles generally have one attached to the engine. Pumps mounted near the fuel

tank use electricity to pull fuel from the tank toward the engine. Automobiles with fuel

pumps attached near the engine use gravity to pull fuel into the engine.

Fuel FilterFuel filters are critical for optimal performance and long engine life. These

components are usually installed at both ends of the fuel pump to filter particles that would

otherwise inhibit combustion and clog engine components. Regular inspection of fuel

filters is necessary to keep a fuel system performing at a high level.


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Fuel InjectorsFuel systems built after 1986 have fuel injectors. These electronic valves open and

close to send a computer-controlled mixture of air and fuel into the engine block. This

speeds up the combustion process, allows for faster engine response during acceleration,

improves fuel economy and lowers vehicle emissions. Fuel injectors depend greatly on

properly functioning fuel filters to maintain peak performance levels.Fuel Delivery Pipe (fuel Rail)

The fuel delivery pipe, commonly referred to as a fuel rail, is designed to hold the

injector in place on the intake manifold. Mounted to the fuel delivery pipe are the pulsation

damper and the fuels pressure regulator. The fuel delivery pipe acts as a reservoir for fuel

which is held under pressure prior to delivery by the fuel injector.

CarburetorsA carburetor is the predecessor of fuel injection. This component uses gravity to

create the appropriate mixture of air and fuel before sending it into the engine block. The

device is relatively simple in construction but requires frequent maintenance and is less

efficient than fuel injection.

Fuel Pressure regulatorThe fuel pressure regulator is a diaphragm operated pressure relief valve. To

maintain precise fuel metering, the fuel pressure regulator maintains a constant pressure

differential across the fuel injector. This means that the pressure in the fuel rail will always

be at a constant value above manifold absolute pressure.

Pulsation DamperAlthough fuel pressure is maintained at a constant value by the pressure regulator,

the pulsing of the injectors causes minor fluctuations in rail pressure. The pulsation

damper acts as an accumulator to smooth out these pulsations, ensuring accurate fuel

metering. The fuel pulsation damper is not used on all engines but can be used as a fuel

pressure quick check on those engines which it is used.


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II. Exhaust System

The Engine Exhaust System Components

Exhaust ManifoldThe exhaust manifold moves gases from the combustion chambers of the engine to

the exhaust pipe. It is usually cast iron and its smooth curves improve the flow of exhaust.

Catalytic ConverterAs stated above, the catalytic converter helps reduce harmful emissions from engine

exhaust. It uses a combination of heat and metals that act as catalysts. A catalyst is a metal

(or chemical) that causes other chemicals to go through a reaction without being affected

itself. The inside of the catalytic converter consists of metals such as aluminum oxide,

platinum palladium. These metals cause the carbon monoxide and hydrocarbons to react

and produce water vapor and carbon dioxide which are much less harmful to theatmosphere.

ResonatorThe muffler alone cannot totally quiet engine noise. Many exhaust systems also

include a resonator which acts as a mini muffler. They are usually straight pipes filled with

sound muffling materials. The resonator can be either before or after the muffler in the

exhaust system.

Exhaust PipeExhaust pipe connects all the other parts of the exhaust system.

MufflerThe muffler quiets the noise of the engine. There are two sorts of mufflers. Those with

baffled chambers to reduce noise; as sound waves move through this type of muffler, they

bounce off the baffles and expend their energy inside the muffler, losing force and volume.

The other type the exhaust is forced straight through a perforated pipe that contains metal,
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fiberglass, or other sorts of sound-absorbing material. This muffler is designed to reduce

back pressure (exhaust going back up the pipes) and consequently makes a little more

noise.

Tail PipeThe tail pipe comes out of the muffler, past the rear bumper of the vehicle, directing

exhaust gases away from the vehicle. On many newer cars it will also serve as a decorative

function and is tipped in chrome.

III. Lubrication System

Engine Lubrication System Components

Engine sumpThe sump is normally bolted to the lower part of the engine, and is used as a

reservoir to hold the lubrication oil. It is from here that oil is picked up, pumped around theengine and returned when it has performed its function.

Oil Pump and StrainerAs the sump sits at the bottom of the engine, oil must be pumped upwards and

around the engine and pressure. An oil strainer (a basic filter made from wire mesh) is

fitted in the lowest part of the sump, and is attached to a tube which joints I tot the oil


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pump. The oil pump, driven by the engine, draws up oil through the strainer and pickup

pipe, and forces it around the engine.

Oil GalleriesOil galleries are passageways that are cast in the cylinder block and head during

manufacture. They direct oil to vital engine components and return it to the sump when

finished.

Positive Crankcase Ventilation (PCV)In PCV, a series of pipes and valves are connected to the crankcase. These are able to

vent pressure and fumes into the engines inlet manifold, where they become involved in

the normal combustion process. This reduces emissions released to the atmosphere.

Pressure relief ValveAn oil pump is capable of providing sufficient quantities and oil pressure, even when

the engine is running slowly. As the engine speeds up, oil flow and pressure rise. To

prevent this becoming to much, an oil pressure relief valve is fitted. This consists of a

spring-loaded plunger, which is normally fitted near the output of the oil pump. As the

engine runs and the oil pump operate, spring pressure holds the plunger closed. As engine

speed increase and oil pressure rises, the plunger is lifted off its seal and any excess oil or

pressure is returned to the sump/ this allows a constant oil pressure to be maintained

under all engine operating conditions.

Oil Filter

The job of the filter is to maintain a clean flow of oil to the engines mechanical parts.

The oil filter is a replaceable pleated paper element, designed to strain small particles of

dirt and debris from the lubrication oil. It is fitted in line with the oil pump. It is usually

contained in a housing designed to allow easy access, so it can be replaced during routine

maintenance.


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IV. Cooling System

The Engine Cooling System Components

The RadiatorThe radiator core is usually made of flattened aluminum tubes with aluminum strips

that zigzag between the tubes. These fins transfer the heat in the tubes into the air streamto be carried away from the vehicle. On each end of the radiator core is a tank, usually

made of plastic that covers the ends of the radiator, On most modern radiators, the tubes

run horizontally with the plastic tank on either side. On other cars, the tubes run vertically

with the tank on the top and bottom. On older vehicles, the core was made of copper and

the tanks were brass. The new aluminum-plastic system is much more efficient, not to

mention cheaper to produce. On radiators with plastic end caps, there are gaskets between

the aluminum core and the plastic tanks to seal the system and keep the fluid from leaking

out. On older copper and brass radiators, the tanks were brazed (a form of welding) in

order to seal the radiator The tanks, whether plastic or brass, each have a large hose

connection, one mounted towards the top of the radiator to let the coolant in, the other

mounted at the bottom of the radiator on the other tank to let the coolant back out. On thetop of the radiator is an additional opening that is capped off by the radiator cap. Another

component in the radiator for vehicles with an automatic transmission is a separate tank

mounted inside one of the tanks.
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Radiator Cooling FansMounted on the back of the radiator on the side closest to the engine is one or two

electric fans inside a housing that is designed to protect fingers and to direct the air

flow. These fans are there to keep the air flow going through the radiator while the vehicleis going slow or is stopped with the engine running. If these fans stopped working, every

time you came to a stop, the engine temperature would begin rising. On older systems, the

fan was connected to the front of the water pump and would spin whenever the engine was

running because it was driven by a fan belt instead of an electric motor. In these cases, if a

driver would notice the engine begin to run hot in stop and go driving, the driver might put

the car in neutral and rev the engine to turn the fan faster which helped cool the engine.

Racing the engine on a car with a malfunctioning electric fan would only make things worse

because you are producing more heat in the radiator with no fan to cool it off.

The electric fans are controlled by the vehicle's computer. A temperature sensor monitors

engine temperature and sends this information to the computer. The computer determines

if the fan should be turned on and actuates the fan relay if additional air flow through theradiator is necessary.If the car has air conditioning, there is an additional radiator mounted

in front of the normal radiator. This "radiator" is called the air conditioner condenser,

which also needs to be cooled by the air flow entering the engine compartment.

Pressure Cap & Reserve TankThe radiator pressure cap is a simple device that will maintain pressure in the

cooling system up to a certain point. If the pressure builds up higher than the set pressure

point, there is a spring loaded valve, calibrated to the correct Pounds per Square Inch (psi),

to release the pressure.

When the cooling system pressure reaches the point where the cap needs to release this

excess pressure, a small amount of coolant is bled off. It could happen during stop and gotraffic on an extremely hot day, or if the cooling system is malfunctioning. If it does release

pressure under these conditions, there is a system in place to capture the released coolant

and store it in a plastic tank that is usually not pressurized. Since there is now less coolant

in the system, as the engine cools down a partial vacuum is formed. The radiator cap on

these closed systems has a secondary valve to allow the vacuum in the cooling system to

draw the coolant back into the radiator from the reserve tank (like pulling the plunger back

on a hypodermic needle) There are usually markings on the side of the plastic tank marked

Full-Cold, and Full Hot. When the engine is at normal operating temperature, the coolant in

the translucent reserve tank should be up to the Full-Hot line. After the engine has been

sitting for several hours and is cold to the touch, the coolant should be at the Full-Cold line.

Water PumpA water pump is a simple device that will keep the coolant moving as long as the

engine is running. It is usually mounted on the front of the engine and turns whenever the

engine is running. The water pump is driven by the engine through one of the following:

A fan belt that will also be responsible for driving an additional componentlike an alternator or power steering pump
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A serpentine belt, which also drives the alternator, power steering pump andAC compressor among other things.

The timing belt that is also responsible for driving one or more camshafts.The water pump is made up of a housing, usually made of cast iron or cast aluminum and

an impeller mounted on a spinning shaft with a pulley attached to the shaft on the outside

of the pump body. A seal keeps fluid from leaking out of the pump housing past thespinning shaft. The impeller uses centrifugal force to draw the coolant in from the lower

radiator hose and send it under pressure into the engine block. There is a gasket to seal the

water pump to the engine block and prevent the flowing coolant from leaking out where

the pump is attached to the block..

ThermostatThe thermostat is simply a valve that measures the temperature of the coolant and,

if it is hot enough, opens to allow the coolant to flow through the radiator. If the coolant is

not hot enough, the flow to the radiator is blocked and fluid is directed to a bypass system

that allows the coolant to return directly back to the engine. The bypass system allows the

coolant to keep moving through the engine to balance the temperature and avoid hotspots. Because flow to the radiator is blocked, the engine will reach operating temperature

sooner and, on a cold day, will allow the heater to begin supplying hot air to the interior

more quickly.

Bypass SystemThis is a passage that allows the coolant to bypass the radiator and return directly

back to the engine. Some engines use a rubber hose, or a fixed steel tube. In other engines,

there is a cast in passage built into the water pump or front housing. In any case, when the

thermostat is closed, coolant is directed to this bypass and channeled back to the water

pump, which sends the coolant back into the engine without being cooled by the radiator.

Freeze PlugsWhen an engine block is manufactured, a special sand is molded to the shape of the

coolant passages in the engine block. This sand sculpture is positioned inside a mold and

molten iron or aluminum is poured to form the engine block. When the casting is cooled,

the sand is loosened and removed through holes in the engine block casting leaving the

passages that the coolant flows through. Obviously, if we don't plug up these holes, the

coolant will pour right out.

Plugging these holes is the job of the freeze-out plug.

Head Gaskets & Intake Manifold GasketsA typical head gasket is usually made of soft sheet metal that is stamped with ridges

that surround all leak points. When the head is placed on the block, the head gasket is

sandwiched between them. Many bolts, called head bolts are screwed in and tightened

down causing the head gasket to crush and form a tight seal between the block and head.

Head gaskets usually fail if the engine overheats for a sustained period of time causing the

cylinder head to warp and release pressure on the head gasket. This is most common on

engines with cast aluminum heads, which are now on just about all modern engines. Once

coolant or combustion gases leak past the head gasket, the gasket material is usually
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damaged to a point where it will no longer hold the seal. This causes leaks in several

possible areas.

Heater CoreThe hot coolant is also used to provide heat to the interior of the vehicle when needed.

This is a simple and straight forward system that includes a heater core, which looks like asmall version of a radiator, connected to the cooling system with a pair of rubber hoses.

One hose brings hot coolant from the water pump to the heater core and the other hose

returns the coolant to the top of the engine. There is usually a heater control valve in one

of the hoses to block the flow of coolant into the heater core when maximum air

conditioning is called for. A fan, called a blower, draws air through the heater core and

directs it through the heater ducts to the interior of the car. Temperature of the heat is

regulated by a blend door that mixes cool outside air, or sometimes air conditioned air with

the heated air coming through the heater core. This blend door allows you to control the

temperature of the air coming into the interior. Other doors allow you to direct the warm

air through the ducts on the floor, the defroster ducts at the base of the windshield, and the

air conditioning ducts located in the instrument panel.

HosesThere are several rubber hoses that make up the plumbing to connect the components

of the cooling system. The main hoses are called the upper and lower radiator hoses.

These two hoses are approximately 2 inches in diameter and direct coolant between the

engine and the radiator. Two additional hoses, called heater hoses, supply hot coolant from

the engine to the heater core. These hoses are approximately 1 inch in diameter. One of

these hoses may have a heater control valve mounted in-line to block the hot coolant from

entering the heater core when the air conditioner is set to max-cool. A fifth hose, called the

bypass hose, is used to circulate the coolant through the engine, bypassing the radiator,

when the thermostat is closed. Some engines do not use a rubber hose. Instead, they mightuse a metal tube or have a built-in passage in the front housing.

These hoses are designed to withstand the pressure inside the cooling system. Because of

this, they are subject to wear and tear and eventually may require replacing as part of

routine maintenance. If the rubber is beginning to look dry and cracked, or becomes soft

and spongy, or you notice some ballooning at the ends, it is time to replace them. The main

radiator hoses are usually molded to a shape that is designed to rout the hose around

obstacles without kinking.
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V. Charging System

The Engine Charging System Components

AlternatorAn alternator is a generator that produces an AC voltage. The alternator is driven bythe rotation of the engine crankshaft. Thus, it only produces an electrical output when the

engine is running. The output from the alternator varies with the speed of the engine. The

alternator provides the electrical Power source for the Charging System.

RectifierA rectifier is used in order to convert the AC output of the alternator to direct

current (DC), which is needed by the battery.

Voltage RegulatorThe voltage regulator maintained the voltage from the charging system to the

battery within the certain limits. The regulator prevents the undercharging or overcharging

of the battery.

BatteryThe battery supplies current to energize the alternator field coil. The battery also acts

as a voltage stabilizer. The battery must always retain attached to the electrical system

while the engine is running.


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VI. Ignition System

The Engine Ignition System Components

The Ignition switchThere are two separate circuits that go from the ignition switch to the coil. One

circuit runs through a resistor in order to step down the voltage about 15% in order to

protect the points from premature wear. The other circuit sends full battery voltage to the

coil. The only time this circuit is used is during cranking. Since the starter draws aconsiderable amount of current to crank the engine, additional voltage is needed to power

the coil. So when the key is turned to the spring-loaded start position, full battery voltage is

used. As soon as the engine is running, the driver releases the key to the run position

which directs current through the primary resistor to the coil.

The DistributorDistributor, device that sends a high-voltage electric current to spark plugs in an

internal-combustion engine. The distributor conducts electric current to spark plugs in the

correct sequence and at the right times. The current makes the spark plug discharge an

electric spark into the engines combustion chamber. The electrical spark ignites a mixture

of fuel and air, creating heat energy that the engine converts to mechanical energy. Thesparkplugs must discharge, or fire, in a certain order and at exact moments in the engines

cycle. Otherwise, fuel will burn at the wrong times or not at all. Many older vehicles still in

use have distributors. In newer vehicles, distributors have been replaced with computer-

operated ignition systems.


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Ignition CoilThe ignition coil is nothing more that an electrical transformer. It contains both

primary and secondary winding circuits. The coil primary winding contains 100 to 150

turns of heavy copper wire. This wire must be insulated so that the voltage does not jump

from loop to loop, shorting it out. If this happened, it could not create the primary

magnetic field that is required. The primary circuit wire goes into the coil through thepositive terminal, loops around the primary windings, then exits through the negative

terminal. The coil secondary winding circuit contains 15,000 to 30,000 turns of fine copper

wire, which also must be insulated from each other. The secondary windings sit inside the

loops of the primary windings. To further increase the coils magnetic field the windings

are wrapped around a soft iron core. To withstand the heat of the current flow, the coil is

filled with oil which helps keep it cool. The ignition coil is the heart of the ignition system.

As current flows through the coil a strong magnetic field is built up. When the current is

shut off, the collapse of this magnetic field to the secondary windings induces a high voltage

which is released through the large center terminal. This voltage is then directed to the

spark plugs through the distributor.

Ignition WiresThese cables are designed to handle 20,000 to more than 50,000 volts, enough

voltage to toss you across the room if you were to be exposed to it. The job of the spark

plug wires is to get that enormous power to the spark plug without leaking out. Spark plug

wires have to endure the heat of a running engine as well as the extreme changes in the

weather. In order to do their job, spark plug wires are fairly thick, with most of that

thickness devoted to insulation with a very thin conductor running down the center.

Spark PlugsThe ignition system's sole reason for being is to service the spark plug. It must

provide sufficient voltage to jump the gap at the tip of the spark plug and do it at the exactright time, reliably on the order of thousands of times per minute for each spark plug in the

engine. The modern spark plug is designed to last many thousands of miles before it

requires replacement. These electrical wonders come in many configurations and heat

ranges to work properly in a given engine.

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