Final Grade: __ (10%)
ENME221 Engine Tear Down Assignment
Attending the lab and completing this assignment is a
course requirement
This is an individual report
Name: Ned Hancox
Student ID:83485828
Due 9:00am 14th October
13/10/2022
Submission
• Upload to the Learn drop box this document, use PowerPoint or the
Apple equivalent.
• Upload a PDF version.
• Due: 9:00 am Friday the 14th of October..
• Where sketches are required, sketch on paper then photograph or
scan and paste it on the page. DO NOT PASTE COPIED FIGURES FROM
THE WEB or similar
• Grades shown on each sheet are % of your final course grade.
Late penalties shall apply.
•-10% of your achieved assignment grade for up to 1 hour late
•-20% of your achieved assignment grade 1-24 hours late
•-20% of your achieved assignment grade for each 24 hours thereafter
We try to accommodate unforeseen issues. If you think you have a valid reason for late submission please contact the course
coordinator before it is due.
Show how a 4 stroke spark ignition internal combustion engine works (use your own sketches): (1%)
/1%
Two typical applications are: petrol cars, motorbikes
Name three primary fuels it can use? Petrol, LPG, Ethanol
Generally, how is it lubricated? Oil within crankcase
Show how a 2 stroke spark ignition internal combustion engine works (use your own sketches): (1%)
/1%
A two stroke engine does not have an oil sump, how is it lubricated? Oil is mixed with the fuel. When this fuel oil
mixture enters the crank case the oil deposits on surfaces and lubricates them
What fuel is typically used? Petrol mixed with oil
Two typical applications: chainsaws, weed eaters
Why? Because the engine Is lubricated by the fuel/oil/air mixture it can be run in any orientation as long as the
carburettor allows and will always have adequate lubrication as apposed to a 4 stroke where if it is on an angle may
be starved of oil. 2 stroke engines are also light compared to there 4 stroke counterparts and have fewer moving parts
so are easier to manufacture.
Show how a 4 stroke compression ignition internal combustion engine works (use your own sketches): (1%)
/1%
What fuel is used? diesel
Two typical applications are: Tractors , Trucks Why? Compression ignition engines provide more torque then spark
ignition engines so are better for slow speed application where large amounts of power are required.
The lab engine uses a carburettor to control the flow and mix the air and fuel in the correct ratio. Show
the basic principals of a carburettor (Use your own sketches): (0.5%)
Modern cars don’t use a carburettor, how do they introduce the fuel? (Use your own sketches): (0.5%)
/1%
What materials and manufacturing processes were used for the following?
• Crank case (0.25%)
• Material cast iron
• Primary manufacturing methods casting machining
• Camshaft (0.25%)
• Material cast iron
• Primary manufacturing methods: casting then machining
• Fuel Tank (0.25%)
• Material steel
• Primary manufacturing methods. Stamping, welding
• Air Cleaner Cover (0.25%)
• Material: Plastic
• Primary manufacturing method: injection moulding
/1%
Engine Details
Stroke: 42mm
Bore Diameter: 62mm
Connecting Rod Length: 63.5mm
Cylinder head clearance volume: 9cc
Gasket thickness: 1mm
/1%
What is the swept volume (Show working): 126.8 cc
Calculate the compression ratio (Show working): 11.55 : 1 (0.5%)
What is the typical compression ratio for a compression ignition engine? 16 : 1 (0.5%)
Create a graph similar to the one on the next page that shows the actual piston motion compared to simple
harmonic motion and slider crank (Show the equations used)
The line on the graph represents simple harmonic motion.
Recreate the graph and add the piston motion you measured and calculated.
Starting with the intake stroke, show when the valves open and close and when the spark fires.
Replace this graph with your version.
/1%
Piston Position and Engine Timing
TDC
0
0
100
200
300
400
500
600
exhaust open
exhaust close
700
-5
Piston Position (mm)
-10
-15
-20
-25
-30
-35
-40
-45
BDC
simple Harmonic
Piston distance (mm)
Crank Angle (deg)
intake open
intake close
spark
The spark fires before or after top dead centre (TDC)? before Why? When ignited it takes a while for the air fuel mixture to
burn. By igniting it before TDC it gives time for the mixture to completely combust after TDC
Section 3.
/0.5%
Treasure Hunt
In the lab, engines are dismantled for you to view the parts. Take and paste photos
of these engine components. Place a marker by the part with your user code.
Example:
Place Photo Here
Nylock Nut:
Helical Gear:
Treasure Hunt
In the lab, engines are dismantled for you to view the parts. Take and paste
photos of these components. Place a marker by the part with your name.
Sleeve Dowel:
Cylinder Head Gasket:
/0.5%
Treasure Hunt
/0.5%
Engines are dismantled for you to view the parts. Take and paste photos of
these components. Place a marker by the part with your user code.
Flange Nut:
Choke Valve:
Treasure Hunt
/0.5%
In the lab, engines are dismantled for you to view parts. Take and paste photos
of these components. Place a marker by the part with your user code.
Camshaft:
Decompression mechanism:
Treasure Hunt
In the lab, engines are dismantled for you to view the parts. Take and paste
photos of these components. Place a marker by the part with your user code.
Rolling Element Bearing:
Hydrodynamic Bearing:
/0.5%
Treasure Hunt
In the lab, engines are dismantled for you to view the parts. Take and paste
photos of these components. Place a marker by the part with your user code.
Pull Starter Sprag Clutch:
Magneto Coil:
/0.5%