Group 11 -GM V-6 Engine Gate3

Cause For Corrective Action

The completion of this gate went very smoothly for the group. The only real major issue that arose on this gate was the time at which this gate was completed. Portions of this gate were completed well in advance of the due date but other portions were not completed until the night before it was due. This was different from the previous gates in which everything was completed, at least for the most part, well in advance of the impending due date. In terms of correcting this, the group and the project manager discussed the issue and decided it was a onetime thing due to the overloaded schedule each group member has been dealing with in the past two weeks. For the next gate, the only major change that will be made to the plan is that the group will sit down and discuss their schedules two weeks before the project is due. This will allow the team to distribute portions of the project accordingly and assure that the gate is completed in a timely manner.

From last gate, the major issue was the communication between Group 10 and Group 11. This issue has been discussed by the two groups. Communication between the two groups in this gate went well with minimal issues. The discussion of the communication issue went well and hopefully that will be evident in the next gate. The next gate requires the engine be reassembled, which will require a great deal of interaction between the two groups.

Component Summary

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Table 1:Component Summary

Component Name	Image of Component	Quantity Used	Function	Material	Manufacturing Process	Fastener Used
Throttle body		1	Regulates the amount of air taken into the engine.	Aluminum	The throttle body is not one single piece. It's an assembly of 3 smaller pieces, all of which have been cast, finished and then assembled.	3 10mm bolts that are 4.4375in long
Intake Manifold Cover		1	Protects the Intake Manifold and provides an airtight seal between the throttle body and the intake manifold. Prevents unwanted substances from entering the engine.	Molded Plastic with a rubber seal	Injection molded.	6 10mm Bolts that are 2.25in long
Fuel Injector		1	Injects gasoline into the engine to allow combustion to take place	Plastic and rubber	The plastic was injection molded and the rubber hoses were	2 1/4in Allen Screws
Distributor		1	Fires the spark plugs located on the cylinder heads in the proper order.	Bakelite (a nonconductive heat resistant plastic) and Inner shaft of cold rolled Steel	High heat and pressure process of several layers to process bakelite and Low Temperature Rolling	One 1/2in bolt
Intake Manifold		1	Diverts optimal amounts of air into the cylinders. Also contains piping for fuel to flow.	Aluminum	Casting and Finishing	8 1/2in bolts that are two inches long and the threads extend from the bottom up 3/4in
Valve Cover		2	Seals the cylinder heads from outside material and protects the valve springs and rockers.	Plastic	Injection Molding	3 1/2 bolts
Exhaust Manifold		2	Connects to engine block at exhaust port. Removes exhaust gases from the cylinders and sends them through the cat converter and eventually out of the muffler.	Iron	Casting	6 9/16in bolts
Cylinder Head		2	Housing for multiple components including the rockers, valves, and valve springs.	Steel	Casting and finishing	6 1/2in bolts that are 2in long are located towards the outside edge of the head. 7 1/2in bolts that are 3.25in long are located towards the center of the motor.
Rocker Arm		12	Opens and closes the valves via the motion of the rotating camshafts allowing fuel and air into the cylinders for combustion.	Carbon Steel	Forging	1 1/2in nut and 1 1/2 in bolt.
Pushrod		12	Transfers motion from the lifters on the cam to the rockers and valve springs which in turns opens the valves.	Carbon Steel	Rolled	No fastener used, it is held in place by the lifters and the rocker arms.
Valve Spring		12	Returns the valves back to their closed position after the spark plug ignites the fuel air mixture in the cylinders. Assists pushrods in transferring motion to the valves.	Carbon Steel	Coiling and hardening	No fastener used, it is tightly attached to the valve.
Valve		12	Regulates the entry and exit of the Fuel-air mix and exhaust from with in the cylinders.	Carbon steel	Rolling	No fastener used, it is held in place by the valve spring.
Lifter		12	Converts the horizontal movement of the camshafts to vertical motion that gets transferred to the rockers and valves.	Carbon steel	Casting and machining	No fastener used, it is held in place by the camshaft and the push rods.
Water Pump		1	Pumps coolant through the engine block in order to cool the engine.	Alluminum body containing mostly plastic and cast iron components	Casting and machining	4 9/16in bolts that are 2.375in long
Oil Pan		1	The oil pan acts as a reservoir for oil. The oil pump will take oil from the reservoir to lubricate engine internals.	Aluminum	Casting and forging	10 1/2in bolts
Oil Pump		1	Takes oil from bottom of oil pan and pumps it through the engine in order to lubricate engine internals and components.	Aluminum	Casting and forging	2 5/8in bolts
Piston		6	Transfers the energy produced by the combustion of the fuel air mix into rotational energy at the crankshaft.	Aluminum	Machining	It is attached to the connecting rods via a roller which allows it to spin.
Connecting Rod		6	The connecting rod connects the piston to the crankshaft. The connecting rod in conjunction with the crankshaft converts linear energy into rotational energy.	Steel	Forging	2 9/16in bolts that attach to the retainers which wrap around the crank.
Piston Ring		12	Provides a tight seal between the combustion chamber and the pistons.	Aluminum	Stamping	No fastener is used, it is held in place by the cylinder wall.
Serpentine Pulley		1	Connects to crank and uses a belt so that the crank can turn outer engine components such as the power steering pump and alternator.	Steel	Casting	3 9/16 in bolts
Timing Cover		1	Protects the timing chain and timing gears from unwanted materials and substances.	Plastic	Injection Molding	6 3/8in bolts of varying lengths
Timing Chain		1	Connects both timing gears in order to turn them in conjunction with one another.	Steel	Stamping	No fastener is used, it is held in place by two sprockets.
Camshaft		1	Raises and lowers the lifters which in turn raises and lowers the pushrods which pivots the rocker arms thus opening and closing the valves.	Iron	Machining and casting	No fastener is used, it is held in place by the holes in the block
Harmonic Balancer		1	The harmonic balancer reduces most of the torsional vibration caused by the crankshaft. It also serves as a pulley.	Steel	Stamping	It is held on to the crankshaft by a keyway.
Retainer		1	Holds the crankshaft safely inside the engine block.	Steel	Stamping	It is attached by two 9/16in bolts.
Balancing shaft		1	Offsets engine vibrations due to unbalanced engine designs.	Iron	Casting	It is held in place by the holes in the block.
Flex Plate		1	Stores large amounts of rotational energy caused by it's large rotational inertia. It transfers rotational energy received from the crankshaft and applies it through the clutch and transmission into the drive shaft.	Steel	Casting	7 3/4in bolts of the flywheel
Crankshaft		1	Connects pistons via connecting rods. The crankshaft converts linear motion from the pistons into rotational energy. That energy is transferred to the flywheel which passes it on to the drive shaft.	Iron	Casting	No fasteners are used, the crankshaft is held in place by bearings, the holes in the block, and a system of pulleys.

Figure a. Summary of Major Components in the Engine

Product Analysis

Complexity Definition

Complexity of a component can be divided into two categories, complexity of the shape and complexity of the function. These two categories will effectively cover the complexity of each component. A component can have a very complex task to complete, but that does not necessarily mean that it has a complex shape. The complexity of the shape and function of each individual component will be rated on a scale of 1-5. The table below shows the meaning of each rating.

Table 1: Scale of Complexity

Complexity of	Meaning of a 1	Meaning of a 2	Meaning of a 3	Meaning of a 4	Meaning of a 5
Shape	Very basic uniform shape	Very basic shape but not entirely uniform	Shape is not basic and not uniform	Shape is complex in geometry	Shape is very complex in geometry
Function	Simple function	Simple function of lesser importance	Simple function of higher importance	Complex function of lesser importance	Complex function of higher importance

Pushrods

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Figure 1. Pushrod

Component Function

The push rods connect the camshaft, through the lifters, to the valve train. By connecting these two parts of the motor, the push rods assure the proper intake of oxygen and the proper exhaustion of the byproducts.

• The push rods really only serve one function, to connect the camshaft to the rockers.
• The main flows associated with this component are the flow of oxygen into the motor and the flow of reaction byproducts out of the motor.

This component is located inside of the engine block. It extends down from the head all the way down through the engine block to the camshaft. Obviously, this will be an environment with very high temperatures and many different applied forces.

Component Form (Geometry, Material, and Appearance)

The general shape of this component is a rod. The ends of the rod are rounded off. This shape allows easy interface with the lifters and rockers. The shape is cylindrical in order to achieve smooth motion. It allows a slight margin of error in the movement of the pushrod. It allows a slight twisting motion while still operating smoothly.

• The most notable thing about this component is its’ symmetrical nature. It has rotational symmetry if it is rotated about its longest axis, and it is symmetrical along its x axis, y axis, and z axis.
• The push rods are 3-dimensional having a length, width, and height in all locations.
• The push rods are 7.125in long and have a .25in diameter

It is a steel component and the main reason for this is the fact that it needs to be fairly lightweight, yet strong and fairly cheap. Steel was deemed the most effective in order to address the economic issues of cost to manufacture, and fuel economy because the heavier the push rod, the worse the fuel economy will be.

This component is exceedingly light; it is not even a pound.

The pushrods are made from carbon steel.

• Manufacturing processes didn't effect the material selection nearly as much as functionality did. The pushrods need to be very strong and durable to reliably serve their function
• The carbon steel is a good choice because it's fairly light weight but very strong.
• The main factor involved in this design is economics. A lighter push rod means better fuel efficiency, while a heavier push rods means worse fuel mileage. Also, more friction on the push rods mean worse fuel economy.

The aesthetic properties are actually quite impressive to view. The rod is extremely lustrous and is chrome in color.

• The reason it is chrome is due to the highly polished nature of the part. It is so highly polished because it needs to maintain a low coefficient of friction inside the motor. By being so well polished, and with the addition of oil, the push rods can easily slide up and down in the block.
• The surface finishes of the pushrods are very smooth. This causes a small friction coefficient inside the engine.

The finish is for functional purposes only and not for aesthetics. The pushrods were never intended to be seen by the operator, therefore having no aesthetic purpose. The surface finish is purely for functional purposes, reducing the coefficient of friction, thus reducing the amount of force needed to make them move.

Manufacturing Methods

The push rods were made through the shaping and forming process of rolling.

• The most obvious evidence is the fact that it was clearly shaped and formed in order to get the shape since there are no cutting marks on the component. Since it was shaped and formed, it still could be die cast, however, the absence of draft angles indicate it was not cast. The shape of the rod is indicative of rolling the steel into that shape.
• If it were cast or machined, there would be imperfections in the shape of the rods which could lead to the push rods breaking or being severely damaged. By rolling it, the rod shape will be much more smooth and precise than with die casting or machining.

The decision to roll the push rods took into account the economic concern of long-term durability of component. If the component breaks down fairly early into the product’s lifetime, General Motors will likely have to recall the motors of these vehicles potentially costing them millions of dollars. Therefore it is vitally necessary for the part to be durable enough to last a longtime.

Component Complexity

The pushrods are not overly complex. We rated the complexity of shape as a 1 on our scale. The shapes are very basic. The shape of the pushrods are cylindrical rods which are all identical. The pushrods are rated as a 3 on our complexity of function scale. The function of the pushrods is fairly simple, but it is integral to the function of the engine. The pushrods are constantly moving while the engine is on. They are constantly receiving motion from the lifters, and are constantly transferring that motion to the rockers.

Throttle Body

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Figure 1b. Throttle Body

Component Function

The throttle body performs the function of allowing air into the engine through the manifolds to take parts in the combustion of the fuel. Depending on how far open the throttle is, determines how much power the engine is able to produce. The only other functions that the throttle body takes part in is the relaying of information back to the computer to help make sure that the engine runs smoothly. When it comes to flows, the initial input is user interaction, which leads to the intake of air into the engine resulting in combustion and the overall functioning of the engine. For this motor and almost all other motors, the throttle body functions on the top of the engine, exposed to the environment and not internally located in the motor like many other parts crucial to its functioning.

Component Form (Geometry, Material, and Appearance)

The general shape of the throttle body is a three dimensional rectangle with a cylinder located at the center in which the air flows through. The dimensions of this rectangle are 4 5/8 inch long, 4 3/8 inch wide and 2 9/16 high with a 3 1/2 inch circular hole in the center. The rectangular shape of the throttle body only plays a role in its’ fastening to the intake manifold but the circular passage in the center is key to smooth airflow into the engine. Roughly, the throttle body weighs 5 pounds and is made mainly of aluminum with some steel components. Overall, the choice of producing it from aluminum is due to the metals’ light weight and the very little contact that the throttle body will have with heat. When it comes to how manufacturing impacted the material choice, the only factor may have been how easy it is to machine and form aluminum. Where there is steel used in the component is anywhere that might see some kind of mechanical movement, especially where the throttle cable links to the throttle body. The only reason for this use of materials is due to is strength of aluminum. Otherwise, no global, societal, economic or environmental concerns could have been influential in the production of the throttle body. Aesthetically, the throttle body has no roles and as long as it functions it could be made to look like anything. It is gray in color, which is the natural color of aluminum and the steel used and has a rough finish on the outside and a smooth one where the air passes through. The smooth finish is to allow air to flow easier and faster to the motor. Aesthetically, there is no reason for the type of finish.

Manufacturing Methods

When taking a look at the throttle body the overall aluminum body is cast and some machining was done on the inside and bottom where precision is needed for fitment. Evidence to support this are the lines left on the sides from the forms used in the casting process and the overall rough exterior of the component. Where the aluminum was machined, there is a highly polished surface that is much smoother than those that are cast. The reasons for casting and machining the throttle body were most likely because they were the simplest and cheapest ways of producing the part. Almost any material can be cast and machined along with any shape, so the aluminum body and rectangular shape did not have a large impact on the production methods.

Component Complexity

The throttle body is not a very complex component; with its main job as regulating the flow of air it may be an important task but one that can be done simply. When looking at he three categories above, all together they are meant to make the throttle body as simple, reliable and cheaply produced as possible. This simplicity is carried into the interactions with the throttle cable being pulled and the specified amount of air entering the throttle body and engine.

Camshaft

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Figure 1c. Camshaft

Component Function

The function of the camshaft is to ultimately open and close the valves and turn the distributor shaft. The cam first transfers its “elliptical” motion via the lobes of the shaft to the lifter/pushrod assembly. That motion is then transferred to the rockers, which pivot pushing the valves down. There is a lobe for each cylinder. They are offset from each other causing the valves to open at the proper time to let air in, or let exhaust gases out.

• The cam overall has one major task, to open and close the valves. It is however part of an important system. It connects via timing gears to the crankshaft. When the crankshaft turns, it turns the cam, opening and closing the valves in the proper order and timing. The cam also turns the distributor shaft, causing the proper firing order.
• There are several flows dealing with the camshaft. The camshaft converts elliptical rotational motion into linear motion. The actual shaft moves rotationally, while the lobes move elliptically. That motion gets transferred to the lifters, which convert it to linear motion.

The camshaft operates in a high heat location. The nature of the cams movement, and the amount of movement it incurs, causes it to heat up greatly. There are many points of contact on the cam, which need to stay cool and lubricated to properly function. Oil and lubricants help to keep the camshaft cool and rotating smoothly.

Component Form (Geometry, Material, and Appearance)

The inner shape of the camshaft is cylindrical while the lobes are elliptical (tear drop shaped). The inner shape could be square if it was well balanced and still operate smoothly. However being cylindrical is preferred as it wouldn't have to be as exact and precise to operate smoothly.

• The camshaft is axis-symmetric while it rotates. The lobes move in an off-axis, offset fashion. The cam is very notable by it’s teardrop shaped lobes.
• The cam is 3-dimensional having a length, width, and height in all locations.

The camshaft is cylindrical because it needs to properly rotate at its’ points of contact. The lobes are shaped elliptically and are offset from each other in order to open and close valves at different times. If the lobes were shaped cylindrically, or had the point of the lobe in the same location, all of the valves would open at the same time, causing all cylinders to fire at the same time, which would not properly function.

The camshaft weighs roughly 6-7 pounds.

The camshaft is made of iron.

• The manufacturing processes did not influence the material chosen. The cam needs to be relatively light weight, but above all very hard, strong, and durable.
• Hardness is the most important property for the camshaft to have.

Aesthetically, the camshaft is very smooth and shiny due to being heavily machined in order to maintain low friction at points of contact.

• These properties serve a very important purpose. Since the cam rotates constantly and pushes the lifters, it needs to be very smooth on all surfaces in order to turn smoothly.
• The heavy machining of this component caused a very shiny, smooth, metal surface. The machining achieved a much higher surface quality then if it were to be cast or another similar process. Machining was the best choice for manufacturing.
• The surface finish of the camshaft is very smooth. This causes a small friction coefficient between the lobes and lifters as well as the cam and its’ mounting points.

The finish is for functional purposes only and not for aesthetics. The cam is never intended to be seen by the operator, therefore having no aesthetic purpose. The surface finish is purely for functional purposes, reducing the coefficient of friction, thus reducing the amount of force needed to make it rotate.

Manufacturing Methods

The cam was made using machining and casting.

• The very smooth even finish shows that the cam was machined. Before it was machined it was likely cast. There is some evidence of draft towards the center of the cam.
• The material was picked for functionality of ease of manufacturing.
• The fairly simple shape impacted the manufacturing methods. The shape was able to be cast fairly easily. Since the cast left a lower quality surface finish, machining was necessary. The machining left the cam with a high luster, metallic like surface finish.

Component Complexity

The cam is a fairly complex component. We rated it a 2 on our complexity of shape scale. The shapes are very basic but are not necessarily uniform. The overall shape is a simple cylinder. The most complex shapes are those of the lobes, which are tear drop shaped. They are all the same shape, but are offset in their angles from each other, making them slightly more complex. We rated it a 3 on our complexity of function scale. The function of the camshaft isn't overly convoluted, but it is a very important function where everything needs to function correctly. The cam is constantly receiving motion from the crank shaft and constantly inputting motion to the lifters. It is part of a very complex system.

Distributor

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Figure 1d. Distributor

Component Function

The function of the distributor is to transfer electricity from the ignition coil to the spark plugs in the proper firing order. A gear on the camshaft drives the distributor shaft. The metal on the rotor makes contact with a spring loaded carbon brush that is connected to the high voltage cable. The metal on the rotor arm than passes just close enough to the output contact of the spark plugs for the electrical current to jump the gap and ignite the spark plug.

• The distributor shaft drives the oil pump.

• There is a flow of electrical energy within the distributor. There is also a flow of rotational energy along the distributor shaft.

It operates on the exterior of the engine, allowing for greater airflow to reach this part. It being on the outside of the motor is one of the reasons that plastic can be used in this case. Due to the large number of components operating in it's vicinity, this is a high heat environment in which the component functions.

Component Form (Geometry, Material, and Appearance)

The shape of this component is a disk at the top with a shaft extending down into the motor.

• It is rotationally symmetrical however this is its only symmetry.
• The component is three dimensional. It needs to be three dimensional in order to properly extend down into the motor to drive the oil pump and distribute electrical charge to the spark plugs.
• It extends down six inches into the motor and it has a diameter of four inches.

The components shape is coupled with the job it most performs because the spark needs to be distributed to the spark plugs at precise timings. Therefore, a circular head allows the spark to be distributed at regular intervals. This is why it has that axis of symmetry.

The component is very light, weighing about a pound or so.

The component is made of Bakelite, which is a plastic, and steel. The steel extends down into the motor and interfaces with the oil pump. The bakelite stays outside the motor.

• Manufacturing decision did not really influence the material it was made out of in this case. The bakelite is a heat resistant and non-conductive. This was already a highly suitable material for the component and manufacturing processes did not come into play in the decision to use it.

The main factor considered here was the societal factor of safety. If the distributor was made of something conductive, the vehicle would run the risk of catching the oil on fire. The distributor is black on the top. The colors may be driven purely by aesthetic since the distributor is a visible part of the motor. There is no real surface finish to speak of, it is just regular molded plastic. this is most likely because the distributor already looks good and does not need a surface finish.

Manufacturing Methods

The manufacturing method used to make this part was injection molding.

• The main evidence for this comes from the fact that the material is plastic. Also, the marks from a mold can clearly be viewed on the completed distributor.
• The use of plastic meant that injection molding was an option, had the distributor been entirely metal, this would not have been an option.

The main reason for this method is due to economic factor. Mainly because injection molded plastic is quite cheap to make.

Component Complexity

The shape of the component is rated as a two in complexity. This is because the shape is very basic, but it is not uniform. The complexity of the function of the component is rated as a three. Just from looking at the distributor on the motor, it is not at all clear what the function is supposed to be. However, there are a few clues that indicate its function, such as its connection to the oil pump and the presence of wires. If the distributor still had its spark plug wires connected to it, the function may be a bit more intuitive. The three categories above impact complexity because the shape can be complex and the function can be complex, but they are not necessarily related. A component can have a complex form with a basic function or vice versa.

Intake Manifold

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Figure 1e. Intake Manifold

Component Function

The primary function of the intake manifold is to supply the air/fuel mixture to the cylinders. It is essential for the fuel mixture to be evenly distributed between the cylinder heads in order to optimize efficiency and performance for the engine.

• A partial vacuum exists within the intake manifold that can be used to help drive auxiliary systems such as power assisted breaks, emission control devices, cruise control, power windows, and other various systems.
• The primary flow of this component is a material flow that consists of the injection of the fuel mixture into the cylinders.

The intake manifold sits on top of the engine block allowing it to maintain a high airflow to combine with the fuel mixture. The engine block gives off a large amount of heat from the various components and processes contained within, making this a high heat area.

Component Form (Geometry, Material, and Appearance)

The intake manifold has a very complex overall shape. It has a spot for the fuel injector to sit near the center the center of the component. It also contains piping for the fuel to flow.

• There is a basic symmetry down the center of the component, and has a distinctive appearance from the rest of the components.
• It is primarily 3-dimensional, with a length, height, and depth.

The shape of the intake manifold is essential for the air/fuel mixture to be evenly distributed between the cylinders. Its shape allows the fuel injector lines to properly reach the cylinders, while still providing room for other components in the engine block.

The intake manifold weighs around ten pounds.

The piston is made of cast aluminum.

• Manufacturing decisions most likely affected the decision to use aluminum, because aluminum is a relatively easy material to shape and finish. Since the component has such a complex shape, it would be safe to assume that the manufacturers decided that aluminum would be the best choice in casting and finishing this component.
• A specific material property is not needed for it to function, because only the shape of the component is necessary for it to function.
• One of the Global factors influencing this decision are that aluminum is widely available. Another factor is that this component is not exposed to any external elements besides the air which moves through the filter into the cylinder. Even with the passing air, aluminum would be a good choice of material due to good resistance to corrosion versus other metals such as steel which have high corrosion factors
• Economic factors which influence this component are those such that aluminum is widely available and fairly inexpensive. It also has a decent life length before breaking down and corroding, which provides a longer life of the compressor and less maintenance cost for the owner.
• Environmental factors were likely not heavily considered in the deciding aluminum to be a material due to the fact that aluminum is not a heavy metal and that there is no intended disposal of the component after a specific amount of time.
• Societal factors were likely also not heavily weighted.

The aesthetic properties of the component are shiny on the inner surface due to being finished after casting. The outside is left as is after casting.

• There is no purpose aesthetically for this component.
• The component is a shiny silver color on the inside, likely caused by the machining during the manufacturing process. On the outside it is a flat gray color, since the finish was not
• The surface finish of the intake manifold is smooth on the inside. This is so there is little problem with the flow of the air/fuel mixture.

The finish is for functional purpose only. The consumer is not meant to see the inside of the intake manifold.

Manufacturing Methods

The intake manifold was first cast and then machined for smoothness.

• Casting is evident due to parting lines down the middle of the intake manifold. These parting lines are clear indications of an initial process of casting to create the overall shape. The inside surface then went through a machining process to smooth out the inside.
• The process was not chosen because of the material. The material was most likely chosen because of the the low cost and ease of going through this process.
• The shape likely affected the process, because casting would be the most efficient way to create such a complex shape.

Global factors taken into consideration may have been that aluminum casting is available everywhere, not limited to one area.

Societal factors were most likely not taken into account for the decision to cast the aluminum.

Economic factors were very important in the decision to cast the part due to the fact that casting is faster and cheaper then using machining techniques alone to create the aluminum part. A combination of casting and machining was used to achieve the best economic outcome for manufacturing.

Environmental factors taken into account are the ability to make the part a significant number of times without wasting any resources.

Component Complexity

The complexity of the shape of the intake manifold is a 5, because of the complexity of the overall design. The complexity of the function however is only a 2, because it only guides the air/fuel mixture to the cylinders.

Solid Modeled Assembly

Figure 2. Solid Modeled Assembly

• The components shown here are the camshaft, lifters, push rods, rockers, valve springs, and valves. The group choose this assembly because this is what controls the chemical reactions taking place in the motor. Without the proper intake stroke and exhaust stroke, the motor can not function. Really, without this assembly, the motor ceases to generate power. The valvetrain assembly was modeled using Autodesk Inventor Pro 2010.

Figure 2b. Throttle Body Assembly

• The group also did the throttle body. The group did this because this controls the amount of power the engine is outputting. This assembly was modeled using Solidworks 2010.

Engineering Analysis

Figure b. Combustion Process

One of the major components of almost any type of motor is the piston. The piston is what causes the crankshaft to be turned and is therefore where an engine really gets its power. Since this component is vitally necessary to the functioning of the engine, it would be of the utmost importance to perform a full and complete engineering analysis on the piston. The major question regarding a piston is how light can the piston be made while ensuring it does not break down? Clearly the piston should be as light as possible in order to reduce rotational resistance, however, the piston also needs to be able to withstand the forces from the reaction of the gasoline and oxygen, the upward force from the connecting rod, and the forces from the cylinder wall. In order to complete this analysis, first the engineer would have to state the problem. The problem here, as stated previously, is how light can the piston be made while ensuring it does not break down? Then, the engineer would have to diagram the problem. Then he would have to make assumptions. There are several assumptions that would be fairly obvious to make. First off, the individual would have to assume that only oxygen and octane were being combusted. Also in this combustion, the engineer would probably be safe to assume that oxygen is the limiting reagent in the reaction since if gasoline was the limiting reagent, gasoline would be wasted which is clearly not preferable. This assumption allows the engineer to approximate the amount of heat the piston is being exposed to in the system. The engineer would also probably assume an evenly divided force across the top of the piston. This assumption makes it far easier to calculate how the strong the piston needs to be. He would also have to make an assumption regarding the amount of upward force the connecting rod can apply. It would not be too difficult to find the maximum amount of force the connecting rod could apply. The connecting rod is connected to the crankshaft at a certain distance from it. This means the connecting rod provides a torque force to the crankshaft. All that needs to be done is to find the amount of force that is needed to turn the crankshaft. Since the pistons fire one at a time, one piston would have to exceed this force. After making these assumptions, the engineer would be ready to figure out what equations are governing this problem.

First off, Octane reacts with oxygen in the following equation:

2C8H18 +25O2-----16CO2+H20

From there, we can figure out what the amount of heat released per mole of Octane would be using Hess’s Law.

H(reaction)=Hf(products)-Hf(reactants)

Both the Hf(products) and the Hf(reactants) can easily be looked up by an engineer in any sort of chemistry reference material. The

The change in maximum temperature that the piston could be exposed to could be found by using the following equation:

H(reaction)=Cm(change in temperature) C= specific heat of reactants

This equation will give you the maximum temperature that the piston will be exposed to inside the motor.

The maximum force on the piston could be found using the following equations:

Torque required to turn the crank=(Force)*(Radius)

Here, the force would be equivalent to the amount of force the connecting rod exerts on the piston.

Then by using these equations to perform the calculations, the engineer can figure out an approximate temperature the piston will be exposed to in the system. After the engineer performs a check on his calculations, he can then start analyzing the data. In the analysis, the individual can rule out materials which will melt at a temperature lower than the temperature that the engineer just found will be present in the motor. Other materials will then be ruled out due to the amount of force imparted on the piston by the connecting rod. This will leave the engineer with a list of possible materials that should be able to with stand the heat and forces inside the motor. From there, the engineer would need to further eliminate materials based on cost. If a material is too expensive for the product to be profitable, it obviously would need to be eliminated. From this point, the engineer would probably have the list of materials whittled down to only a few and he potentially could begin testing pistons made of different materials. Obviously, this would depend on the company’s economic standing. If this was a smaller company, creating several piston prototype pistons may not be economically possible, so the engineer may have to pick only one for further testing. However if it is a larger company with the resources for testing multiple prototypes, this should be done by simply placing them in a motor and running the motor in order to see how well they endure the stresses inside the engine. This would be done for a short period of time and then check to see if the piston has been damaged or if any components around it show signs of abuse. Also, it would be done for long term wear in order to see if the pistons had the durability to survive say fifty thousand miles or one hundred thousand miles. Clearly, these would be highly expensive tests and only a company with a large amount of resources would be able to afford such testing, however, such testing could prove to be invaluable to a company if a new lighter material was found to be safe for use in a motor.

So, the engineering analysis would look something like this:

Problem Statement: How light can a piston be made while ensuring it does not fail?

Diagram: See figure b.

Assumptions: Octane is being combusted. Evenly distributed force from the reaction on the top of the piston. Oxygen is the limiting reagent The connecting rod provides a maximum force to the piston when the crankshaft is just about to begin turning

Governing Equations:

2C8H18 +25O2-----16CO2+H20

H(reaction)=Hf(products)-Hf(reactants)

H(reaction)=Cm(change in temperature) C= specific heat of reactants

Torque required to turn the crank=(Force)*(Radius)

Design Revisions

Titanium Flexplate

The first proposed design revision is to replace the current flex plate with one made of titanium. Currently, the flex plate is made of steel. The change in material from steel to titanium would address one major concern. It would address long term economic concerns for the vehicle due to improved fuel mileage. The titanium flex plate would decrease rotational weight on the motor leading to less resistance. This decreased resistance would increase the gas mileage of the vehicle and allow for more power to be transferred to the wheels. Since one of the main purposes of the Vortec 4300 LG3 is to be fuel efficient, the decreased rotational inertia would most certainly be appealing to General Motors. The improved power would also improve the vehicles power to weight ratio and allow the operator to haul more material. This would also address an economic concern, because that consumer could now haul more work materials per trip than previously, potentially allowing the individual to save time and money in having to make multiple trips.

This change would only have one notable adverse impact, the increased initial cost. As of November 12th, titanium was trading for about eleven dollars and twelve cents per pound, while cold rolled steel was trading for about 34 cents per pound. Over the past two years, titanium has been as expensive as thirteen dollars and seventy five cents per pound and as inexpensive as eight dollars and fifty cents per pound. In the past three years, steel has been as expensive as fifty seven cents per pound and as cheap as twenty five cents per pound. These prices clearly demonstrate steel’s initial cost superiority over titanium. Steel is not only cheaper, but its price is much more consistent. The more consistent price is obviously more preferable since an inconsistent price could lead to wild swings in the profitability of the product. Still, the current steel flywheel is only about five pounds. Since titanium is sixty percent the weight of steel, the titanium flywheel would only be about an additional thirty two dollars and sixty four cents. Of course, this is assuming comparable forming costs for the two materials.

Another potential concern is the change in durability for the backing plate due to the material change. Without heat treating or any other hardening process, titanium has a hardness of approximately 160 VHN. Steel on the other hand, when fully hardened can have a hardness of 900VHN. Clearly the steel used for this flywheel is not fully hardened and is most likely an alloy of some sort, however, it is still harder than the titanium flywheel will be without heat treating. This means that there is a possibility of long term durability concern due to the force of the torque converter on the flex plate. This concern clearly necessitates testing to ascertain if a flex plate made out of titanium could with stand the load from the engine.

Still, despite these potential issues, the titanium flex plate should be examined further. The main purpose of Vortec 4300 LG3 is to provide smaller trucks and SUVs with enough power to haul materials and tow vehicles, while providing the consumer with decent fuel economy. The titanium flex plate can further that aim on both accounts.

Supercharger

Figure 3. Supercharger model

The second proposed design revision is the addition of a supercharger. A supercharger in its basic form is an air compressor that is run off of a pulley attached to the crankshaft. A supercharger uses the rotational inertia of the crank to rotate two helical shaped shafts that mesh together and compress air. The compressed air is then forced down into the cylinders. Superchargers force more air into each cylinder than they can normally intake by means of atmospheric pressure alone. This is called “boost” and typically a supercharger will create about 10-12 psi of boost. This results in more oxygen to catalyst the combustion of gasoline creating a larger and more evenly distributed explosion across the top of the piston thus creating more horsepower. Because superchargers increase the power of the engine by utilizing more oxygen, they do not require a larger engine superchargers condense incoming air so the requisite mass fits in the relatively small volume of the engine, therefore fuel efficiency is increased and cars can be made lighter by reducing the need for extra cylinders to create power.

The addition of the supercharger would allow this motor to be used in a much greater variety of vehicles. Originally, this motor was designed for use specifically in small trucks and SUVs. The exact model, the LG3 was only used in Blazer's and S10s. The extra horsepower generated by the addition of a supercharger would lead to greater fuel efficiency in smaller cars and provided extra power needed to increase hauling capacity in larger trucks. This addition could potentially allow the GM V6 to be used in larger trucks such as a Silverado where extra power is needed for towing or hauling. The addition of this supercharger would likely add about $3000 dollars to the current price. The ability to use this engine in a wider selection of vehicles however, could potentially lower the overall cost.

An image of the proposed supercharger can be viewed below. This assembly was modeled using Autodesk Inventor Pro 2010.

Active Fuel Management

As gas prices continue to rise, fuel efficient vehicles become more and more appealing to consumers. The price of gasoline and the instability of that price is a serious economic concern for most Americans. The addition of Active Fuel Management to the motor would significantly improve its fuel economy. This would help address the economic concerns of the consumer over gas prices. Active Fuel Management is the General Motors technology that allows a V-6 or a V-8 motor to operate as an Inline three cylinder or Inline four cylinder motor under certain driving conditions. According to the Environmental Protection Agency, the vehicle equipped with this Active Fuel Management can expect to improve its fuel mileage by about six to eight percent. Clearly, this is a large improvement in fuel mileage and it is applicable to trucks and has been used in truck and SUV motors. The 2010 Yukon XL, the 2010 Cadillac Escalade, and the 2011 Chevrolet Tahoe come equipped with Active Fuel Management. Also, the Chevrolet Suburban, Silverado, and Avalanche come available with this option. The addition of this technology also addresses the large societal factor of the United States’ consumption of oil. Congress has enacted legislation mandating that all companies making vehicles that are “manufactured for sale in the United States” meet the Corporate Average Fuel Economy of thirty five miles to the gallon. Previously, small trucks and SUVs have been exempt from the Corporate Average Fuel Efficiency (CAFÉ) legislation; however as of 2016, they are included. Therefore it is vitally important for a small truck motor like the Vortec 4300 LG3 to meet the new standards and to address the societal concern of over consumption of gasoline.

Active Fuel Management works on the premise that a powerful motor is inefficient under normal driving circumstances. Therefore, it is possible to reduce the number of cylinders that are functioning and still keep the vehicle operating at an acceptable level. The vehicle still can operate the electrical devices it is equipped with and it can still maintain its speed. The only real notable change is the amount of fuel being consumed. If more power is needed, the inactive cylinders readily reactivate to provide the additional power. This is the major advantage of this technology, since the motor still would have a six cylinders, it would still have the torque necessary to haul large loads.

This technology effectively shuts cylinders off by keeping the exhausting valve closed. This is done through a solenoid control valve assembly. This assembly receives a signal from pressurized oil on when to activate and deactivate the hydraulic lifters. Since the lifters control the exhausting of byproducts and in-taking of reactants, the cylinder well will be filled with the byproducts of the combustion reaction and no more intake of reactants will take place. The gaseous byproducts in the cylinder act as a gas spring that keep the piston from contacting the head. Obviously a great number of sensors and electronic controls would be necessary in order to maintain a seemingly seamless transition from cylinder being inactive to being active and vice versa. This would necessitate the altering of several components on the motor. First and most obviously, hydraulic lifters would need to replace the current ones. Secondly, the solenoid control valve assembly would need to be installed in the motor. Thirdly, the current throttle body would need to be replaced by an electronic throttle controlling device. This would greatly assist in ensuring that the shutting on and off of the cylinders is very difficult for the operator to notice.

Despite the advanced electronic and design, there are some draw backs to this device. First off, it is expensive. All the electronics needed for this make for a more expensive vehicle. Still, the 2011 Chevrolet Tahoe with Active Fuel Management starts at $37,750, while the hybrid starts at $50,735. So despite the increased cost to install this device, it is still quite a bit cheaper than a hybrid. Also, another potential drawback is the durability of the technology. Although General Motors first used the technology in 1981, the current system using the well developed electronic controls debuted in 2005. This means that vehicles using this technology have only been on the road for five years and therefore it is possible that unforeseen failures occur in the system due to the wear and tear of everyday use.

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