Internal combustion engine is either gasoline or diesel design. They are different because of the...
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Internal combustion engine is either gasoline or diesel design. They are different because of the method used for burning the fuel. The mechanical operation
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.
Slide 2
Cylinder block assembly Exhaust system Valve train Lubrication
system Intake system Cooling system
Slide 3
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.
Slide 4
The air/fuel ratio is the amount of air compared to the amount
of fuel. The ideal air/fuel ratio when using gasoline is 14.7 to 1.
This means there are 14.7 parts of air to one part of fuel.
Slide 5
Slide 6
The ratio will fluctuate between 12 to 1 as a rich mixture and
18 to 1 which is a lean mixture. A rich mixture means there is more
fuel in the combustion chamber. A lean mixture means there is less
fuel
Slide 7
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
Slide 8
Internal combustion engines can be powered by different fuels.
Gasoline is the fuel designed for spark- ignition. All of the
necessary gasoline additives are added during the manufacturing
process ; no additional aftermarket additives are necessary The
result is a carefully blended fuel that is adjusted
seasonally.
Slide 9
the fuel system Is designed to break the liquid fuel into a
vapor and mix them with air.
Slide 10
When combustion occurs, the high pressure pushes the piston
down in the cylinder. 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.
Slide 11
Slide 12
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.
Slide 13
Slide 14
1 How would you summarize the fuel system? 2What would result
if we used fuel additives in the fuel system ? 3Explain what pushes
the piston down in the cylinder? 4How would you explain the part,
that converts up and down motion to rotary motion?
Slide 15
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
Slide 16
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
Slide 17
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.
Slide 18
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
Slide 19
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
Slide 20
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
Slide 21
The engine must rotate two complete revolutions to complete the
four stroke cycle, the crankshaft rotates 720 degrees.
Slide 22
Slide 23
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.
Slide 24
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
Slide 25
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
Slide 26
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
Slide 27
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
Slide 28
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
Slide 29
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
Slide 30
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?
Slide 31
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
Slide 32
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
Slide 33
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
Slide 34
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
Slide 35
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
Slide 36
The bearing is made slightly larger in diameter than the
bearing bore This helps prevent the bearing from spinning inside
the bore
Slide 37
STANDARD BEARINGUNDERSIZE BEARING Has the original dimensions
specified by the manufacturer For a new, unworn, or unmachined
crankshaft 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
Slide 38
Slide 39
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
Slide 40
1. What material can be used on the bearing surface? 2. 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)
Slide 41
It fastens the piston to the crankshaft It transfers piston
movement and combustion pressure to the crankshaft rod
journals.
Slide 42
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
Slide 43
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
Slide 44
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
Slide 45
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
Slide 46
It allows the piston to swing on the connecting rod The pin
fits into the small end of the connecting rod
Slide 47
They seal the clearance between the outer side of the piston
and the cylinder wall They must keep combustion pressure from
entering the crankcase
Slide 48
Combustion pressure pushes the compression rings down in their
grooves and out against the cylinder wall This produces an almost
leak proof seal
Slide 49
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
Slide 50
1. What gives the connecting rod its strength? 2. What are ring
grooves? 3. What is the piston skirt? 4. What are the two different
rings used on the piston? 5. What function does the wrist pin
perform?
Slide 51
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
Slide 52
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
Slide 53
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
Slide 54
Are round machined surfaces in the combustion chamber port
openings. When the valve is closed, it seals against the valve
seat
Slide 55
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
Slide 56
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
Slide 57
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
Slide 58
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
Slide 59
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
Slide 60
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?
Slide 61
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
Slide 62
It controls the flow of air fuel mixture into the combustion
chamber Its the larger of the two valves
Slide 63
Controls the flow of exhaust gases out of the cylinder The
valve closes the port leading to the exhaust manifold
Slide 64
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
Slide 65
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.
Slide 66
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
Slide 67
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.
Slide 68
Also called the rocker cover its a cover over the top of the
cylinder head. It simply keeps valve train oil spray from leaking
out of the engine.