GATE 3

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Complexity Scale/ Categories



In this case complexity is not necessarily defined not only on a scale but also in categories. The last 3 levels pertain only to assemblies which are in this case more complex than highly machined and accurate single parts.

Complexity: 1

  • Single Piece with minimal manufacturing processes requiring no assembly. Size is, in this case, irrelevant to the complexity scale. In this case finishing might be extensive but accuracy is low.

Complexity: 2

  • Single piece with extensive machining and finishing required. In this case, the part is detailed with attention to weight, balance and other specific details. Higher accuracy is required in this case.

Complexity: 3

  • Assembly with few parts which can be assembled entirely by automation. In most cases the part is small. Size is small.

Complexity: 4

  • Assembly with more parts that requires either machining and/or assembly by hand.

Complexity: 5

  • Assembly with many parts that require both machining and assembly by hand. In this case, size is larger than levels 3 or 4.

Given that we have very little information on the exact machining that occurs on specific parts, the description of complexity may consist of 2 levels where information is insufficient.

Component Summary


Throttle body

  • Quantity: 1.
  • Material: Aluminum.
  • Function: To regulate the air intake into the engine.
  • Manufacturing Process: The throttle body is not one single piece but instead an assembly of 3 smaller pieces, each of which have been cast, finished and then assembled.
  • Shape: In this case, a butterfly valve is used. In this case it seems practical given that very little movement is required to change the airflow into the engine and unlike a ball valve, there is much less friction.
  • Why manufacturing process was chosen: Given the large scale of the automobile industry, massive quantities demand fast and automatable manufacturing processes for as many parts as possible. Thus the use of casting and automated machining are necessary.
  • Complexity: 4. It is an assembly with a retracting butterfly valve. In some cases a sensor that feeds information to the ECU is included.

'Upper Intake Manifold

  • Quantity: 1
  • Material: Molded Plastic with a rubber seal
  • Function: To cover the Intake Manifold and provide an airtight seal between the throttle body and the intake manifold preventing other substances from entering the engine.
  • Manufacturing Process: Injection molded
  • Notes on Shape: The part is shaped to cover the top of the intake manifold itself.
  • Why manufacturing process was chosen: Low accuracy mean automation is viable for the large quantities.
  • Complexity: 2

MAF Sensor

  • Quantity: 1
  • Material: Plastic, Aluminum (may also include rubber in tubing).
  • Function: To pump fuel into the cylinders depending on the amount of air coming in (through the throttle body)
  • Manufacturing Process: Injection molded plastic parts and machined aluminum parts.
  • Notes on Shape: No notes on the shape except that the cylinder numbers are imprinted on the body of the injector
  • Why manufacturing process was chosen: number of parts probably require machine assembly
  • Complexity: 3.5

Distributor

  • Quantity: 1
  • Material: Molded plastic exterior and Inner shaft of cold rolled Steel
  • Function: to fire the spark plugs located on the cylinder heads in order so as to maintain the engine.
  • Manufacturing Process: (likely) Injection Molding and Low Temperature Rolling
  • Notes on Shape: [none]
  • Why manufacturing process was chosen: Cold Rolling introduces deformities in the crystal structures of the steel making it stronger. Steel is used in this case as the function requires that it be magnetic.
  • Complexity: 4:
    • The distributor cap contains an assembly of parts that allow the ignition coil to transfer charge to the spark plugs.

Intake Manifold

  • Quantity: 1
  • Material: Aluminum
  • Function: to divert air to the cylinders. Also contains routes for fuel to flow.
  • Manufacturing Process: Casting and Finishing.
  • Notes on Shape: Hollowed out in places to ensure minimum weight
  • Why manufacturing process was chosen: To allow easy automation with low accuracy
  • Complexity: 2

Valve Cover

  • Quantity: 2
  • Material: Aluminum
  • Function: To seal the cylinder heads from outside material.
  • Manufacturing Process: Forging
  • Notes on Shape: [None]
  • Why manufacturing process was chosen: Easiest method given shape and necessity.
  • Complexity: 1

Exhaust Manifold

  • Quantity: 2
  • Material: Iron
  • Function: To remove exhaust air from the cylinders to the car exhaust
  • Manufacturing Process: Casting
  • Notes on Shape: [none]
  • Why manufacturing process was chosen: Not a high level of accuracy required in this case thus casting can be used with minimal machining.
  • Complexity: 1

Cylinder Head

  • Quantity: 2
  • Material: Iron
  • Function: Acts as a housing for multiple components including the rockers, connecting rods, rockers, valves, and valve springs.
  • Manufacturing Process: Casting and finishing
  • Notes on Shape: [None]
  • Why manufacturing process was chosen: The processes were chosen to make the part automatable.
  • Complexity: 2. This part has extensive detail in the shape and cannot easily be shaped after casting, it is difficult to gauge the complexity level.

Rocker Arm

  • Quantity: 12
  • Material: Carbon Steel
  • Function: To open and close the valves through the motion of the rotating camshafts to allow fuel and air into the cylinders for combustion.
  • Manufacturing Process: Forging
  • Notes on Shape: The shape of the rocker has been altered over many years to provide ideal transmission and timing of motion from the camshafts to the valves.
  • Why manufacturing process was chosen: High rate of output of products.
  • Complexity: 1


Pushrod

  • Quantity: 12
  • Material: Carbon Steel
  • Function: To convey motion from the lifters to the rockers.
  • Manufacturing Process: Rolled
  • Notes on Shape: The shape of the head varies widely and can be changed depending on the type of rockers used.
  • Why manufacturing process was chosen: Easiest method for shape.
  • Complexity: 1

Valve Spring

  • Quantity: 12
  • Material: Carbon Steel
  • Function: To return the valves back to their closed position when the spark plug ignites the fuel air mixture in the cylinders.
  • Manufacturing Processes: Coiling, Hardening and Finishing
  • Notes on Shape: The spring is a compression spring that keeps the valve closed at all times (except when the rockers push down)
  • Why manufacturing process was chosen: There are no alternatives to these basic spring manufacturing processes.
  • Complexity: 1

Valve

  • Quantity: 12
  • Material: Carbon Steel
  • Function: To regulate the entry and exit of the Fuel-air mix and exhaust from the cylinders.
  • Manufacturing Process: Rolling
  • Notes on Shape: [None]
  • Why manufacturing process was chosen: Easiest method for given shape.
  • Complexity: 1

Lifter

  • Quantity: 12
  • Material: Carbon Steel
  • Function: To negate the horizontal movement of the camshafts and transfer the vertical motion to the rockers
  • Manufacturing Process: Casting, Machining, and Assembled
  • Notes on Shape: They are cylindrical with a horizontal roller on them to negate the horizontal movement.
  • Why manufacturing process was chosen: Moderate level of accuracy needed.
  • Complexity: 3

Water Pump

  • Quantity: 1
  • Material: Aluminum body with plastic and Cast Iron components.
  • Function: To pump coolant through the engine block to cool the engine.
  • Manufacturing Process: Casting and Machining
  • Notes on Shape: [None]
  • Why manufacturing process was chosen: Multiple parts inside and moderate to high level of accuracy required
  • Complexity: 4. Since we did not disassemble the pump, we cannot determine exactly how complex it really is.

Oil Pickup/Pump Assembly

  • Quantity: 1
  • Material: Aluminum and Iron
  • Function: To take oil from bottom of oil pan and send it to the top of the engine for internal lubrication of the block and components.
  • Manufacturing Process: Casting, Machining, and Forging
  • Notes on Shape: [None]
  • Why manufacturing process was chosen: The high level of accuracy needed due to internal oil flow.
  • Complexity: 3

Piston Assembly

  • Quantity: 6
  • Material: Aluminum
  • Function: To transfer the mechanical energy produced by the combustion of the fuel air mix to the crankshaft.
  • Manufacturing Process: Casting, Machining, and Assembly
  • Notes on Shape: Cylindrical to fit inside combustion chambers.
  • Why manufacturing process was chosen: High accuracy required.
  • Complexity: 2

Piston Ring

  • Quantity: 12
  • Material: Aluminum
  • Function: Seal the combustion chamber around the pistons.
  • Manufacturing Process: Stamping
  • Notes on Shape: Flat and round to fit around piston head.
  • Why manufacturing process was chosen: Many parts can be stamped simultaneously from one sheet of metal.
  • Complexity: 1

Outer Crank Pulley

  • Quantity: 1
  • Material: Steel
  • Function: Connects to crank and has belt so crank can turn outer engine components such as power steering pump and alternator.
  • Manufacturing Process: Casting
  • Notes on Shape: Round to accommodate belt travel around its outside.
  • Why manufacturing process was chosen: Low level of accuracy needed.
  • Complexity: 1

Timing Cover

  • Quantity: 1
  • Material: Plastic
  • Function: To cover the timing chain and timing gears from dirt and water.
  • Manufacturing Process: Injection Molding
  • Notes on Shape: [None]
  • Why manufacturing process was chosen: Best option for thin plastic. Can make parts fast.
  • Complexity: 1

Timing Gear

  • Quantity: 2
  • Material: Steel
  • Function: To connect timing chain to camshaft and timing chain to crank so they can turn.
  • Manufacturing Process: Casting and Machining
  • Notes on Shape: Round to accommodate timing chain travel around its outside.
  • Why manufacturing process was chosen: Basic shape can come from cast but machining is needed for high level of accuracy required.
  • Complexity: 1

Timing Chain

  • Quantity: 1
  • Material: Steel
  • Function: To turn timing gears simultaneously.
  • Manufacturing Process: Stamping and Assembly
  • Notes on Shape: [None]
  • Why manufacturing process was chosen: Stamping can make the small pieces quickly but it needs to be flexible so they can ride around the timing gears. Therefore, assembly is needed to put in the dowels that hold the small pieces together.
  • Complexity: 2

Camshaft

  • Quantity: 1
  • Material: Iron
  • Function: The raise and lower the lifters, which in turn raises and lowers the pushrods, which pivots the rocker arms, which opens and closes the valves.
  • Manufacturing Process: Casting and Machining
  • Notes on Shape: Cylindrical with ‘bumps’ that the lifters ride on.
  • Why manufacturing process was chosen: The basic cylinder shape is casted easily but the ‘bumps’ have to be machined due to the very high accuracy required.
  • Complexity: 4

Timing Gear Retainer

  • Quantity: 1
  • Material: Steel
  • Function: To hold the timing gear in place.
  • Manufacturing Process: Stamping
  • Notes on Shape: [None]
  • Why manufacturing process was chosen: Easy to make many parts simultaneously.
  • Complexity: 1

Outer Crank Retainer

  • Quantity: 1
  • Material: Steel
  • Function: To hold the crank inside the block.
  • Manufacturing Process: Stamping
  • Notes on Shape: [None]
  • Why manufacturing process was chosen: easy to make many parts simultaneously.
  • Complexity: 1

Oiler Rod

  • Quantity: 1
  • Material: Iron
  • Function: To assist in internal lubrication by “throwing” oil around inside the engine.
  • Manufacturing Process: Casting
  • Notes on Shape: Cylindrical with “wings” to help “throw” oil in multiple directions.
  • Why manufacturing process was chosen: Easiest for shape and low level of accuracy required.
  • Complexity: 1

Design Changes and Analysis


After discussion with our technical experts, we have decided that any engine improvements can come in three different ways.

The first (and probably the most important) to improve the efficiency is to improve its Weight to horsepower ratio by reducing the weight of the heavy, cast iron components (i.e. the heads, the block and the flywheel). The Cast Iron engine block and cylinder heads, when replaced with aluminum, are approximately 50% lighter and reduce the weight of (just) the engine block from approximately 163 lbs to 74 lbs. From a viability point of view, many high performance cars use cast aluminum engine blocks and cylinder heads and the basic procedures of finishing are very similar albeit costlier. Furthermore, in case of damage to the block itself, aluminum blocks are easier to fix.

The drawbacks of this conversion however are that and aluminum block leads to more wear and tear on the engine block. The aluminum flywheel also does not provide enough rotational inertia for a quick start, however, given that the Vortec V6 is not used for drag racing or in sports cars, these factors do not affect the functionality of the engine for the end user.

Further improvement can come from the addition of roller rockers in the cylinder heads. Roller rockers reduce the friction between the connecting rods and the rockers, thus reducing the wastage of energy in the form of heat dissipated. However, given that the difference is not substantial, it would not necessarily be value for money.

Increasing the size of the valves and ports would allow more of the fuel-air mixture into the chambers thus increasing the speed at which the pistons move, thus providing a greater torque to the crankshaft. This is a very viable option to improve the torque of the engine with very few drawbacks. The biggest drawback in this case would be greater wear and tear on the engine block.

Solid Model's of Piston and Rod Assembly'


We appointed Keith Billanti as the group's expert on solid modeling. Keith has experience creating solid models from his own personal hobbies and had many ideas on how to make our models stand out.

Keith used a modeling software called Rhinoceros to create our images. He chose this program because it is has all of the features of the more well known software packages and unlike other companies that will give a 1 year license to students, Mcneel (the company that designed the program)- allows students to purchase the full program at a fraction of the actual retail price.

While working on our project, Keith discovered and purchased an add on for Rhinoceros called Brazil. Brazil is an advanced rendering program that allowed him to apply realistic textures and material finishes to our drawings, making them look real. For more info on these programs go to www.rhino3d.com

Finally, Keith chose the piston and rod assembly because he felt that there were not too many other parts of the engine that would provide interesting models and at the same time- be a reasonable amount of work.

These are the final solid models of the piston and rod assembly.

Builtpiston.jpg
Explodedghost.png
Explodedpistonfullrender.jpg
Ghostedringset.png
Ghostedrod.png
Ghostpiston.png
Fullrenfinal.jpg