Internal combustion engine is
either gasoline or diesel design.
They are different because of
the method used for burning the
fuel.
The mechanical operation of
each style of engine is nearly
identical.
In an engine, fuel is burned to
create mechanical motion.
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Cylinder block
assembly
Exhaust system
Valve train
Lubrication system
Intake system
Cooling system
Combustion is the process of
igniting a mixture of air and
fuel at the correct time.
In the combustion process a
mixture of air and fuel is
drawn into a cylinder.
The compressed mixture is
ignited to create energy for
vehicle motion.
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The air/fuel ratio is the amount of air compared to
the amount of fuel.
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The ideal air/fuel ratio when using gasoline is 14.7
to 1.
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This means there are 14.7 parts of air to one part of
fuel.
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The ratio will fluctuate
between 12 to 1 as a
rich mixture
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and 18 to 1 which is a
lean mixture.
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A rich mixture means
there is more fuel in
the combustion
chamber.

A lean mixture means
there is less fuel
1. What two designs can a internal combustion engine
be?
Gasoline and Diesel
2. Summarize 4 major components of the engine?
Lubrication system, Valve train, Exhaust system, Engine block, Intake
system, Cooling system
3. Combustion is the process of igniting a mixture of
--------- and ------------ .
Air and Fuel
4. 12:1 Air /Fuel ratio is an example of a ---------mixture
Rich mixture
5. Why do you think we burn fuel in a engine?
To create energy motion to move the vehicle
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Internal combustion engines can be powered by
different fuels. Gasoline is the fuel designed for sparkignition.

All of the necessary gasoline additives are added
during the manufacturing process;

no additional aftermarket additives are
necessary
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The result is a carefully blended fuel that is adjusted
seasonally.

the fuel system Is
designed to break
the liquid fuel into
a vapor and mix
them with air.
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When combustion occurs, the high pressure
pushes the piston down in the cylinder.
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The piston is connected to a connecting rod,
which is connected to the crankshaft.

The connecting rod and crankshaft convert the
up and down motion of the piston into rotary
motion.
As combustion occurs in each cylinder, pulses of
energy are transferred from the pistons to the
crankshaft.
The flywheel, which is a heavy round metal plate
attached to one end of the crankshaft.
1
How would you summarize the fuel system?
2
What would result if we used fuel additives in the
fuel system ?
3
Explain what pushes the piston down in the
cylinder?
4
How would you explain the part, that converts up
and down motion to rotary motion?
It is the distance the
piston slides up or down
from TDC to BDC
This takes half a turn of
the crankshaft, 180
degrees for one stroke
TDC - Top Dead Centre
BDC - Bottom Dead
Centre
Requires 4 piston strokes to complete one cycle
or (series of event)
For every four strokes the engine produces one
power stroke (useful energy)
Almost all automobiles use the four stroke cycle
engine
The intake valve is open
and the exhaust valve is
closed
The piston slides down
and forms a low-pressure
area or vacuum in the
cylinder
Outside Air pressure pushes
the fuel and air into the
engine combustion
chamber.
Squeezes the air-fuel
mixture to prepare it for
combustion (controlled
burning)
The mixture is more
combustible when
pressurized
During this stroke the
piston slides up the cylinder
while both of the valves are
closed in the combustion
chamber
The spark plug ignites
and burns the air/fuel
charge driving the piston
downward with
tremendous force.
Since both valves are
closed, pressure forms
on the top of the piston
This is the only stroke
that does not consume
energy
Removes the burnt gases
from the engine and
readies the cylinder for a
fresh charge of air/fuel
mixture
During this stroke the
piston moves up the
cylinder, the intake valve is
closed the exhaust valve is
open
The burnt gases are
pushed out the exhaust
port into the exhaust pipes
The engine must rotate two complete revolutions to
complete the four stroke cycle, the crankshaft rotates
720 degrees.
Bottom end refers to the block, crankshaft,
connecting rods, pistons and related parts.
Another name for this is the Short Block. It
is an assembled block without cylinder heads
and manifolds.
It forms the main
body of the engine.
Other parts bolt to or
fit inside the block
Cylinder are large
round holes machined
through the block from
the top to bottom
The deck
Is the top of the block
surrounding the
cylinders
It is machined perfectly
flat
The cylinder head bolts
to the deck
Water Jackets
Are coolant passages
through the block.
They allow a solution of
water and antifreeze to
cool the cylinders
Are round metal plugs
on the outside of the
block.
They seal holes left in
the block after casting
(manufacturing)
They prevent coolant
from leaking out the
water jackets
Main Bearing Bores
are holes machined in
the bottom end to hold
the crankshaft
Main Caps Bolt to the
bottom of the block
and hold the crank
shaft in place
Harness the tremendous
force produced by the
downward thrust of the
pistons.
It changes up and down
motion of the piston into
rotating motion
The crank fits into the
engine block journals
Counterweights are formed on the crankshaft to
prevent vibration they counter act the weight of the rods and
pistons
Crank snout sticks through the front of the block it
provides a mounting point for the chain, damper and fan
pulley
Crankshaft Flange holds the flywheel
the flywheel
bolts to the flange
*The journals are arranged so 1 cylinder is always on the
power stroke
1.
What is the 4 strokes of the engine?
2.
What is the short block?
3.
What is the deck?
4.
What is the purpose of the core plugs ?
5.
What does the crankshaft do?
Are removable inserts
that fit between the
block main bore and
the crankshaft main
journals
The other half fits into
the block main caps
Oil holes on the upper
bearing line up with
holes on the block
Limits how far the
crankshaft can slide
forward or rearward in
the block
This limits the
crankshaft endplay
Normally one of the
main bearing serves
as a thrust bearing
Steel is normally used for the bearing body or
backing which is in contact with the stationary
part of the engine
Softer alloys are bonded over the backing to
form the bearing surface (plating)
They use Babbitt- lead tin alloy
copper or aluminum
Bearings operate under tremendous loads,
severe temperature variations and abrasive
conditions
Bearing load strength : bearings ability to withstand the
pounding and crushing during engine operation this
can be several tons of force
Bearing conformability: is the bearings ability to adjust
to imperfections in the journal surface
Bearing embedability: the bearings ability to
absorb dirt, metal or other hard particles they
should be able to sink into the bearing material
Bearing Corrosion resistance: the bearings
ability to withstand being acted on by acids,
water and other contaminates in the oil
The bearing is made
slightly larger in
diameter than the
bearing bore
This helps prevent the
bearing from spinning
inside the bore
STANDARD BEARING
Has the original
dimensions specified by
the manufacturer
For a new, unworn, or
unmachined crankshaft
UNDERSIZE BEARING
Designed to be used on
crankshafts that have
been machined to a
smaller diameter
A machine shop can
grind down the journals
if they have been
damaged
It is the space
between the
crankshaft main
journal and the main
bearing insert
The clearance allows
lubricating oil to enter
and separate the
journal and bearing
2.
What material can be used on the bearing
surface?
What are the two types of crank bearings?
3.
What is bearing crush?
4.
What are the sizes of a bearing? (hint if we
have the crankshaft machined)
1.
It fastens the piston to
the crankshaft
It transfers piston
movement and
combustion pressure
to the crankshaft rod
journals.
I Beam is the centre
section of the rod
The shape provides
very high strength to
weight ratio
The rod cap bolts to
the bottom of the rod
body
The rod has a Lower
end, and a Top end
It transfers pressure of
the combustion
(expending gases) to the
connecting rod
Piston Head must be
shaped to match and
work with the shape of
the combustion chamber
Are slots machined in
the piston for the rings
The upper two
grooves hold the
compression rings
The lower piston
groove holds the oil
rings
Piston ring lands: is
the area between and
above the ring
grooves
Piston Skirt: is the
side of the piston
below the last ring, it
keeps the piston from
tipping in the cylinder
It allows the piston to
swing on the
connecting rod
The pin fits into the
small end of the
connecting rod
They seal the
clearance between
the outer side of the
piston and the
cylinder wall
They must keep
combustion pressure
from entering the
crankcase
Combustion pressure
pushes the
compression rings
down in their grooves
and out against the
cylinder wall
This produces an
almost leak proof seal
They prevent engine oil
from entering the
combustion chamber
They scrap excess oil off
the cylinder wall
If too much oil entered
the combustion chamber
blue smoke would
appear in the exhaust
1.
What gives the connecting rod it’s strength?
2.
What are ring grooves?
3.
What is the piston skirt?
4.
What are the two different rings used on the
piston?
What function does the wrist pin perform?
5.
Refers to the cylinder
heads, valves camshaft
and other related
components
These parts work
together to control the
flow of air/fuel into the
engine cylinders
They also control the
flow of exhaust out of the
engine
Bolts to the deck of
the cylinder block
It covers and
encloses the top of
the cylinders
Combustion
chambers are small
pockets formed in the
cylinder heads
The intake and exhaust
ports are cast into the
heads
Intake routes air and fuel
into the combustion
chamber
Exhaust ports routes
burned gases out of the
engine
Are round machined
surfaces in the
combustion chamber port
openings.
When the valve is closed,
it seals against the valve
seat
It consists of the
valves and the parts
that operate them e.g.
camshaft, lifters,
rocker arm , and
pushrods
The valve train must
open and close the
valves at the correct
time
Has lobes that open each
valve
It can be located in the
engine block or in the
cylinder head
Cam Lobes: Are egg
shaped protrusions
(bumps) machined on the
camshaft
Also called a Tappet
usually rides on the
camshaft lobes and
transfers motion to the
rest of the valve train
They fit in the lifter
bores which are
machined holes In the
block or heads
They transfer motion
between the lifter and
the rocker arm
They are used when
the camshaft is
located in the block
A push rod is a hollow
metal tube with a ball
formed on each end
Are used to change
direction and transfer
motion to the valves
They mount on top of
the cylinder head
They are a pivot
mechanism allowing
them to rock back and
forth
1.
What does the word top end refer to?
2.
What are cylinder heads?
3.
What is the valve trains job?
4.
What rides on top of the camshaft?
5.
What is the rocker arms function?
Engine valves open and
close the ports in the
cylinder head
There use to be only 2
valves per cylinder 1
Intake and 1 exhaust
valve
The Intake valve is bigger
then the exhaust valve
It controls the flow of air
fuel mixture into the
combustion chamber
It’s the larger of the two
valves
Controls the flow of
exhaust gases out of
the cylinder
The valve closes the
port leading to the
exhaust manifold
Prevents oil from
entering the combustion
chamber through the
valve guides
Without valve seals, oil
could be drawn into the
engine cylinders and
burned causing blue
smoke
It is used to close the
valves.
It has keepers that fit
into grooves cut in the
valve stem, this locks
and retains the spring.
Bolts to the side of the
side of the cylinder head
or heads. On newer
engines the fuel injectors
and throttle body mount
on the intake
Older engines the
carburetor mounts on it
Also bolts to the cylinder
head.
It fastens over the
exhaust ports to carry
burned gases into the
exhaust system.
Can be made out of cast
iron or light weight
aluminum.
Also called the rocker
cover it’s a cover over
the top of the cylinder
head.
It simply keeps valve
train oil spray from
leaking out of the
engine.