Product Archeology:Product Evaluation
Component Chart
| Material used | Manufacturing process | Thumbnail image | ||
|---|---|---|---|---|
| Air box | Takes in air which will be mixed with fuel, and be combusted | Plastic | Injection molding |  |
| Alternator | Source of DC electrical current in running engine | Copper, Aluminum | Turning |  |
| Bottom engine block | Houses many important components, such as the clutch and gear assembly | Aluminum | Forging, milling |  |
| Cam shaft | Mechanically opens and closes engine valves as it rotates | Cast Iron | Forging, Turning |  |
| Water pump | Circulates water and coolant throughout engine | Stainless steel | Stamping |  |
| Carburetors | Mixes fuel and air to be combusted in the cylinders | Cast iron, zinc, aluminium | Die casting |  |
| Chain | Transfers power from the crankshaft to the cam shaft | Stainless steel | Die casting |  |
| Chain tightener | Keeps the chain connected tightly to the cam shaft | Plastic | Injection molding |  |
| Clutch | Separates the crankshaft from transmission so the gears can be changed freely | Hard ceramic material | Injection molding |  |
| Crank case cover | Cover that provides access to the engine block for simple repairs | Aluminium | Die casting |  |
| Crank shaft | Accept energy from the pistons and transfer it to the cam shaft and transmission | Cast steel | Casting, forging |  |
| Cylinder head | Houses the valves involved in the flows of energy | Aluminium | Die casting and milling |  |
| Exhaust manifold | Collects exhaust gases and exports them out of the engine | Cast iron, stainless steel | Die casting |  |
| Gears | Transfer power from one shaft to another | Steel, aluminium, cast iron | Investment casting |  |
| Oil pan | Holding bay for oil which circulates throughout the engine | Aluminium | Die casting |  |
| Oil pump | Delivers oil to bearings, pistons and cam shaft | Aluminium | Die casting |  |
| Pistons | Harnesses the power of combustion into rotation of the cam shaft | Aluminium | Die casting |  |
| Top engine block | Houses cylinders and pistons | Aluminium | Forging, milling |  |
| Radiator hose | Passes coolant through the engine to keep it from overheating | Aluminium, silicon | Injection molding |  |
| Shifter cam | Translates rotational motion to linear motion | Aluminium | Forging, turning |  |
| Spark plugs | Ignite fuel in the cylinders to power the engine | Aluminium oxide ceramic, steel | Extrusion, knurling, reaming, injection molding |  |
| Starter motor | Initially powers the engine before the engine can function under its own power | Aluminium | Die casting |  |
Component Summary
Complexity Scale
Since there are multiple factors which go into the complexity of a component, we decided to account for all of them in our scale. The scale lists the number of functions a component performs, the level of difficulty that goes into manufacturing the part, the number of flows which interact with the part, and also any sub components that compose the part. The score of functions, flows and sub components is based solely upon the number of each factors that acts with the component. The manufacturing score is based upon the number of processes used to create this part, and also how difficult each manufacturing process is to complete. When they are totaled, the end product is an integer, with 1 being the lowest, and as it increases, so does the component complexity.
Air Box
This plastic box sits on top of the engine and is where the air is taken in. It contains a large filter to clean the air an ensure it enters at the correct angle and pressure. It is two halves tightly sealed together where the air enters through two tubes from either side and is then sucked through the filter. The borders of the chamber before the filter are entirely curved, to hold high pressures while still using plastic. It may also aid in fluid flow calculations. The top and bottom halves are symmetrical, but not to each other. Since it is not visible on the outside of the bike it has no aesthetic appeal. The factors impacting this part’s design are of all four. Plastic is cheap, and since the location of the air box is away from heat this can be used. It is also lighter, so this would make a societal impact on the riding quality of the bike, making it faster and more efficient. It is global in that this would determine the type of air filter used, namely, how environmentally safe is it’s construction and decomposition? This component appears to be injection molded. Since the design if split in two halves it is logical to attribute this to the required “draft” angle. The shape of the part cannot double back more than 180 degrees. Otherwise it can’t be removed from the mold. This would require that the many fastener hole be drilled afterward. I notices that for the high pressure seam fasteners there is a square hole with an internally threaded metal square sitting in it. This was done so that the weak plastic wouldn’t become stripped. This seems to be the easiest way because the mold can be reused and the holes are easy to make. Overall this is a simple component, consisting of only a hollow top half and a filter in the bottom. Simplicity is cheap as it reduces time to design and prepare for manufacturing, as well as easy any needed repairs to the bike.
Component complexity
Number of functions- 1, filter intake air
Flows associated- 1, air through filter
Sub components- 1, air filter
Manufacturing process- 1, die casting
Alternator
This is the source of the spark in each piston chamber. It’s job is to generate a consistent charge from a spinning shaft from the engine. It must endure large amounts of heat due to rapidly changing currents, and intense vibration. It is basically a 6 inch diameter metal ring with dense coils of wire pointing toward the center ;(right hand rule). It sits fixed inside a large metal wheel that has a raised axle and rim surrounding the ring in spinning metal. Not sure exactly how, but since there are charges moving relative to each other there will be electric and magnetic fields. The kinetic energy supplied by the wheel cause charge to flow with a voltage enough to create a spark. It is made out of conductive metal high in strength and weight. The wires are coated in a smooth polymer to prevent a short, though I am not sure it would matter. The two factor impacting the design here would be global and economic. This is an essential part of the engine and it cannot fail. Not only is it responsible for spark, but for the onboard electronics and charging the battery. Headlights, radio, and any other electronically controlled functions depend on this component. There must be requirements to be met here. Economic means meeting these requirements for minimal cost. Since this part is not visible there are no aesthetics, but the casing is exposed and has a logo on it. The core ring must be a perfect circle, this it is made by a turning process. Everything here has axial symmetry and is firmly connected to the center ring. The wire was extruded and pulled to it’s current size and it is tightly wound into a rectangles on the outside of the ring. The casing was likely injection molded due to it’s draft and “halved” design. The core ring has 4 holes drilled in to hold it firmly to the casing. Everything has to be highly conductive metal. The 4 holes in the alternator are drilled at right angles to increase strength and ease stress calculations. This is a simple part requiring very high precision. Though there is only one moving part it must perform predictably and consistently. This is done to ease repairs and construction.
Complexity:8
Flows:0
Energy:1
Electrical Energy
Manufacturing Prcesses:3
Casting, Machining, Drawing
Subcomponents:4
Bottom Engine Block
This holds the crankshaft and transmission components in place. The axles rest in hollow cylinders finished to an absolutely smooth and tight seal. Again the bottom and middle sections of the engine block are molded in halves. The bottom meets along a flat line around the edge. There are no fluid flows here, only dissipation of heat and force. The shapes are determined entirely by the locations of the axles. The crankshaft needs an empty cavity for motion, as do the gears in the transmission, but all available space is ribbed by solid metal to increase strength where needed. I noticed that under each half cylinder axle seat there is a hole and grove cut in to force lubricant between all contacts. There are channels cut behind heat sensitive components to circulate lubricant. This isn’t the only way lubricant and coolant are transported, but each instance is unique. It is as heavy 30 or 40 pounds and seals the space between engine and transmission because that component is “wet”. As the rest of the engine casing it is made of cast aluminum to optimize weight and strength. The primary process here is die casting. The component is cut in half before any shapes double back on themselves. Most of it is a rough finish. But where smoothness and precision are required, such as axle seats and lubricant channels, the finish is high quality. For the axle seats a spinning cutting tool may be used, and a cnc mill for the lubricant channels. Some channels are drilled straight in. Because of these the shaped had to be considered wherever these liquids are needed. This component is complex and precise, needing to hold the axles in place under any stresses. Even so it has likely been kept as simple as possible. All shapes are right angles, even if it would save weight and strength do use another. For instance, some lubricant channels turn suddenly twice instead of moving in a straight diagonal line. This is done to ease repairs and construction.
Component complexity
Number of functions- house other components, hold them in place
Flows associated-0, no flows
Sub components- 0, just engine block
Manufacturing process- 2, die casting, cnc milling
Cam Shaft
This is a pair of rotating shafts with precisely angled protrusions designed to press levers. Precisely, they opens and closes chambers at precise times. Each protrusion is the same size and shape, but differ in angle and location. There are 4 pairs of “triangular” protrusions on each cam shaft corresponding with the 4 cylinders. Between each pair is a smooth bearing it rests on. My guess is that one cam shaft opens chambers and the other closes, and that each shaft is the same but rotated a few degrees apart. One end of each shaft is geared to a chain that times the two shafts with the rpm of the crank shaft. It is about a foot and a half long and weighs 2/3 kilogram. It needs to take significant torque without deforming, thus it uses a heavy metal. The primary manufacturing process forging. Due to the rough finish it may have been heated and pounded into a shaft using two molds pressed together with extreme pressure. Then it could be turned to make smooth the surfaces it rests on. Then the protrusions would be machined to a smooth finish by grinding or milling. The biggest factor to influence the design here is economic. I see that some sections are thickened for no visible reason. This may mean this part is optimized to function at minimal weight and cost. Since it is all one piece of solid metal I’d say it is a simple, high precision part.
Complexity: 3
Flows:0
Energy: 1
Rotational Energy
Manufacturing Processes:2
Casting, Machining
Subcomponents: 0
Water pump
Component Function:
This is a water pump. The blade inside sucks in water and forces it out an exit pipe. That pipe then passes behind the walls of heat sensitive parts. Thermodynamics states that an isentropic process, one of constant heat and entropy, is the most efficient. The water absorbs heat energy from pistons and high friction processes to increase efficiency and prevent warping of the metal. Once the water has absorbed heat it passes through the radiator to cool down and be used again. The inside of the pump is flooded with coolant and it is placed right below the engine block.
Component form:
It is built in two halves and is roughly circular. The top half is the entrance tube that lets in the water directly over the fan blade. As the water spins clockwise and outward the radius of the cavity increases like a flat sea shell. The top half has a constant depth expanding groove cut in it to optimize water flow. The bottom meets the top at a flat border rimmed by a rubber seal. The bottom half houses the spinning blade and the exit tube tangent to the flow’s direction. The shaft sits very firmly in a high pressure rubber seal. There is no noticeable looseness to it. Everything here is sturdy and not aesthetic. The central cylinder has ribs connecting to the four holes that secure the halves together. The environment it functions in has extreme heat and vibration. The pressure within will be extreme. The metal is die cast aluminum- so therefore it is grey. This component helps keep the engine running at a constant temperature and extends the life of the engine. These factors would be economic. Ironically, they didn’t use a rust resistant metal for the shaft because there is rust covering the blades. The external finish is smooth so it can be handled, but the inside is very smooth to ease the flow of water. It all weighs about 1kg and is 14cm long and has a 5cm diameter.
Manufacturing Methods:
It appears to be primarily die cast metal. There are small raised circles on the inside. The outside shape is of considerably lower precision than the inside cavity. The protruding screw holes have a draft to them as do the ribs. There are four holes on the edges, two of them have been drilled straight through, and two are threaded. No shape curves back on itself since the general shape is a pile of cylinders of varying diameter. It only doubles back once, and so making a mold in two halves makes sense. It certainly is cheaper than milling the entire thing, thus this is the cheapest option. The mold can also be reused so this method is an economically based choice. The fan blade is a bent plate of metal bolted to a solid metal shaft with a groove in the end. The blade has some rust so it’s material is not the best for a wet environment. All this is done to save weight and money while maintaining function.
Complexity:4
Everything here is made as simple as possible. It’s function is to suck water in and push it back out and is able to do it with one moving part. This makes it’s complexity low, as low as possible really. It is economically and socially beneficial to make it simple. It is easy for anyone to open and close the shell for a repair. It is equally easy to manufacture due to simple design. It does appear to be a highly perfected design that works well.
Flows: 1
Liquid
Energy: 0
Manufacturing Proceses: 2
Subcomponents; 1
Impelor
Casting, Machining Water Pump Image
Carburetors
Component function:
The function of a carburetor is to mix air with fuel before it is injected into the combustion cylinders. The only other function that the carburetor has is that is allows the user to control the amount of fuel and air that is fed into the engine. There is only mass flow associated with the carburetor since the only thing that happens through it is the flow of gas and air. The environment that it functions is inside the air filter box where it is above room temperature and no other significant feature of notice.
Component form:
The general shape of the component is a mix of a cylinder and a cuboid, there are many smaller details that cannot be explained through writing. The carburetor does not have any notable geometric features, except that all 4 of them inside the engine were identical to each other. It is a relatively complicated three dimensional design. The dimensions of the carburetor can be given as 3.5 x 3 x 4 inches as L x W x H respectively. The overall shape of it is very rugged and complex but through careful observation it can be seen that the basic internal shape is just a curved cylinder for the air and fuel to pass through. The rough estimated weight of the carburetor would be between ¼ to ½ lb. It is made out of mostly metal (likely aluminum) and some plastic parts. Manufacturing decisions definitely did impact the decisions for the choice of materials because the metal had to be an easy to machine substance to be made into such a complex shape such as the carburetor. The function of the carburetor is not related to the material property of the substance that it is made out of. There are no global factors involved for the material used. The societal factors involved in deciding the material is that it is a very safe metal. The economic factors behind the metal choice would be that it is relatively inexpensive for the carburetor use. There are also no environmental reasons behind this choice. When the component is considered, it is very obvious that there are no aesthetic properties to it. It is also hidden away in the air box, so it is not important. The color of the carburetor is silver in nature, very likely because of the fact that aluminum was used to manufacture it. It has a moderate surface finish and it for functional purpose because it does not have a reason to have a finer finish while it still needs to be smooth to handle for repairs and such.
Manufacturing methods:
The carburetor is very likely to have made using die casting because of its complex shape, high level of consistency among all four carburetors, parting lines and the level of surface finish. Material choice definitely impacted this decision because aluminum is relatively easily melted and so it can be die casted easily. The shape impacted this decision for injection molding as well because the part geometry is so complex that it would take much more time and money to create this part in any of the other manufacturing processes. There were no global factors influencing this manufacturing process. There were no societal factors influencing this as well. Economic factors influenced the manufacturing process because die casting is relatively cheap for large scale manufacturing.
Component Complexity: 5
Flows: 1
Energy: 0
Manufacturing Processes: 2
Functions: 2
Subcomponents: 0
Chain
Component function:
The chain transfers force from crankshaft to camshaft to control the times release of valves. it is a very single functioned component so it’s only purpose is to transfer force over a distance. The flow associated with the chain is the flow of mechanical energy through each of the links onto a gear. The component functions in a well lubricated and closed off environment that is inside the engine casing.
Component form:
It is made of numerous identical links that are connected to each other with metal pins. The chain is symmetric in the x axis when it is attached to the gear system. It is a primarily 3 dimensional component because each of the links is made up of multiple 2 dimensional subcomponents and the way it is made to latch onto gears clearly makes it 3 dimensional. The dimensions of the chain can be given as 23 x .5 x .375 inches as L x W x H respectively. The chains basic shape is multiple links with indents in them to lock onto the teeth of gears. The component weights between the range of .25 to .5lbs. the component is likely made with steel or iron from looking at its color. Manufacturing decisions definitely did impact this because steel is very strong and would have a very long lifespan as the chain. The only material property needed for the chain to function is for it to have very good tensile strength. Global factor that impacted this decision would be that steel is very accessible for industries so they would have easy access to it so this component can be made anywhere easily. The strength and reliability of the steel makes it safer, which is a societal factor. The economic factor that had an impact is that steel is a relatively cheap substance so using it can lower cost. The environmental factor is that steel is a recyclable metal so once the engine is done with its operational life, it can be used to create something else. There are no aesthetic factors to the chain because
Manufacturing methods:
Multiple small parts were cut out using traditional machining and then put back together using pins to connect the multiple chain links. The evidence was from basic observation of the chain. Material choice has a small impact in this decision because steel is not too difficult to cut at an industrial level. The shape at which it needed to be cut was not too difficult to do with traditional machining. There were no global factors influencing this manufacturing process. There were no societal factors influencing this as well. Economic factors influenced the manufacturing process because machining is relatively cheap for cutting the chain parts.
Component Complexity: 4
Flows: 1
Energy: 0
Manufacturing Processes: 2
Functions: 1
Subcomponents: 0
Chain tightener
Component function:
The function of the chain tighter is to make sure that the chain that runs the camshaft is always perfectly tight so there is no energy loss in that process. The chain tightner is a very single functioned component and only has the ability to maintain the chain from getting loose off of the gear it is attached to. The flows associated with the component are the mechanical energy and the thermal energy that is transferred and created from its interaction with the fast moving chain. The component functions in a well lubricated and closed off environment inside the engine casing.
Component form:
The component is a long plastic device with tracks to maintain smooth gear movement. It is symmetrical on its x axis; this means that either side of the plastic tracks are identical to each other. It is definitely a 3 dimensional component because of the fact that it is shaped to allow another 3 dimensional component to pass through it. The dimensions of the chain tightner can be given as 6.5 x .625 x .5 inches as L x W x H respectively. The component is shaped as a hollow track and this allows for the gear that is moving at extremely fast speeds to not start to vibrate to much or come loose during operation. The component is very light and unlikely to be over 50 grams from a rough estimate. The makeup of the chain tightner is by a sort of plastic material. Manufacturing decisions definitely did impact this because this part had to be mass produced and they have to find an economic and efficient way to do that. The material properties that the plastic would need are to not overheat from friction easily as well as have the strength to not be damaged easily while in use. Global factors would have forced the engineers to design it to be work as it is supposed to regardless of the weather of the place that the engine would have to be constantly working in. Societal factor would require them that the chain tightner does not get damaged while in use and do damage to the engine while in use and put anyone in danger. Economic factor that influenced the component would be using the most cost efficient material to create the part necessary. The environmental factor that might have been considered is using a plastic material that could be more expensive but less likely to damage often so the company as a whole would not be creating more plastic parts in landfills. The chain tightner does not have any aesthetic properties because of how simple of a component it is and it is never seen by anyone unless for during very serious maintenance. The original color of the chain tightner seem to have been while but from all the oil it had been exposed to, its turned somewhat light brown. It has a moderate surface finish externally but a very smooth surface finish on the track where the chain would have to move through freely and so it is obvious that the reasons for that is functional.
Manufacturing methods:
It is very likely manufactured using injection molding because it is a plastic part with geometries that can be made with injection molding much quicker than any other processes. The likelihood of it being injection molding is concluded from the evidence that the whole part is one solid piece with a very unnoticeable riser mark. The choice of material definitely would have impacted this definition because injection molding is one the easiest ways to create mass produced plastic parts. The shape did impact the method selected because it has an intricate design that would take much longer to create with anything other than injection molding. There were no global factors influencing this manufacturing process. There were no societal factors influencing this as well. Economic factors influenced the manufacturing process because injection molding is relatively cheap for large scale manufacturing.
Component Complexity: 4
Flows: 1
Energy: 1
Manufacturing Processes: 1
Functions: 1
Subcomponents: 0 Chain Tightener image
Clutch
Component function:
The clutch detaches the crankshaft from the transmission so that gears can be changed freely. The only other function the clutch has is that it can act at a temporary way to run the bike as it would be in neutral. There are heat energy from friction and kinetic energy from it velocity so the only flow associated with this system is energy transfer. The component functions in a well lubricated closed environment inside the engine casing.
Component form:
The component is composed of multiple disks attached together with springs and screws. It is symmetric on the x, y, and z axis. It is definitely a 3 dimensional component because for it to work it needs to have motion in all three dimensions and also the component dimensions will explain this as well. . The dimensions of the clutch can be given as an estimated radius of 4 inches and height of 2.5 inches. It needs to have a circular shape because it is in constant rotational motion and the circular shape makes the most sense from the physics applications. The component roughly weights in the range of 5 to 10lb. the component seems to be made out of mostly aluminum and some steel parts. Manufacturing definitely had an impact in this decision making because aluminum could be cut and shaped into the parts necessary for the clutch much easier compared to other metals. There is no specific material property of aluminum that we could determine that would have made it significant for the functioning of the clutch. Since aluminum is a metal that does not rust, it can be put to use in an engine in any areas of the world, which is a global factor that would have impacted the clutch design. The metal is safe and a strong enough material to handle to strain from the engine torque which is a societal factor that influenced ts design. The economic factor that was considered was that aluminum costs more than iron or steel, but in the long run it is a better investment because it does not rust. The environmental factor involved in the decision is that aluminum is a very light metal which lowers the power that the engine has to produce which lowers greenhouse emissions. The component does not have any aesthetic purpose since it it hidden away to anyone but the designers or a mechanic. The color of the component is silver because that is the natural color or aluminum. The component has a smoother surface finish because of functional reasons such as the easiest method of manufacturing.
Manufacturing methods:
The clutch disks are very likely to have been die casted, and the smaller sub parts were made through the use of traditional machining. It is very hard to see evidence of die casting on the disks itself because it has been machined and given a very smooth finish. For smaller parts such as springs and screws it is very obvious that they were created using combinations of traditional machining processes. Material choice wouldn’t make much difference for theses manufacturing methods because they would have to use the same processes to make the parts the way they are, regardless of what metal it is. The shape of the parts involved in the clutch did impact the methods selected because the circular plates with a considerable width cannot be cut easily and so die casting would be the sensible option. The global factor that impacted the choice of manufacturing method is the ease at which this part can be made across any region of the globe through die casting. The societal factor involved would be that die casting gives a smooth finish which can make working with the component easier and safer, the economic factor is that for mass production, die casting is very cost efficient and fast. There are no environmental factors involved in die casting metals.
Component Complexity: 8
Flows: 2
Energy: 0
Manufacturing Processes: 2
Functions: 1
Subcomponents: 3
Crank case cover
Component Function:
The crank case cover is simply a cover that provides access to the engine block for assembly and maintenance of the engine. There are two covers, on over the alternator and one over the clutch. There are no flows associated with either of the two covers. It provides no functional purpose beyond this.
Component Form:
The cover is a three dimensional circular aluminum cover with no symmetry that is secured to the main engine block with bolts. It has a radius approximately of 4.2” and weighs about 3 pounds. It is made from aluminum in order to reduce weight but still be able to withstand the heat of the engine. The material decision was impacted by economic and societal concerns. Reducing the weight of the bike will increase its performance and reduce operating cost. Lower weight also makes for better handling as a lighter bike will respond better and quicker to the rider’s commands.
Manufacturing Methods:
The cover is manufactured through casting and then is finished with milling and drilling. This can be inferred because of the parts relatively low surface quality and because it is a solid piece with simple holes. Economic consideration influence the manufacturing processes because the optimal process is one that reduces both time and cost. Casting and milling would achieve this.
Component Complexity: 4
Flows: 1
Energy: 0
Manufacturing Processes: 2
Functions: 1
Subcomponents: 0
Crank shaft
Component Function: The function of the crankshaft is to accept energy from the pistons and transmit it into the transmission. The pistons are connected to the shaft with connecting rods. When the pistons are forced downwards due to combustion, the assembly creates rotational motion in the crankshaft. The crankshaft also powers the camshafts and the alternator. Power is transmitted to the camshafts and transmission through gears while power is generated in the alternator with a rotor magnet.
Component Form:
The single crankshaft is a steel shaft with no symmetry that has four fluid bearings at even intervals on the shaft. Each bearing has a diameter of 1 inch and are offset to the side of the central axis. These bearing provide the point of contact for the connecting rods. The crankshaft is composed of steel rather than lighter aluminum for durability. Due to its constant rotation, the crankshaft must be able to stand up to the wear associated with friction between parts, however minimal, at high velocities. The shaft also has a high degree of surface finish which minimizes friction and wear. In addition to the bearings, the shaft has gears on each end that transmit energy to the transmission and camshaft. The gear that is attached to the cam chain in 2’’ in diameter and the gear that provides power to the transmission is 5.3’’ in diameter. The shaft also has a large magnet on one end that fits over the alternator. The rotation of this magnet creates current in the coils of the alternator which charges the battery. The magnet has a depth of 1.5’’ and a diameter of 5.5’’.
Manufacturing Methods:
The crank shaft would be cast and then finished with some form of milling. The relatively large bearing parts can easily be made by casting so this backs up this manufacturing theory. While the whole part could be milled, that would not be economical and therefore the manufacturing process should be comprised of multiple stems in order to reduce cost and time.
Component Complexity:12
Flows: 0
Energy:1
Manufacturing Processes:3
Functions: 3
Subcomponents:5
Cylinder Head
Component Function: The cylinder head contains all of the valves that are involved the flow of materials in and out of the combustion chambers and also provides the “lid” for the chamber. This includes fuel/air mixture coming from the carburetors and exhaust gas leaving the combustion chamber. Each chamber has four valves. The valves in the cylinder head are actuated by the rotation of the cam shaft. The opening and closing of the valves is timed with the firing of the spark plugs so the valves extract and insert air/fuel and waste gas at the appropriate times.
Component Form: The head is a rectangular aluminum block with four circular air inlets on the front and four outlets on the back, for material flows in and out. It has a total of 16 valves which are located in 4’’ circular areas that provide the covers for the combustion chambers.
Manufacturing Methods: The cylinder head is manufactured through casting and machining.
Component Complexity: 12
Flows: 2
Air in, Exhaust Out
Energy:1 Heat Out
Manufacturing Processes:2
Functions: 3
Subcomponents: 2
Exhaust manifold
Component Function: The exhaust manifold has the simple function of collecting the exhaust gasses from each cylinder after combustion into one pipe. In doing so it transports mass (waste gas) and heat energy out of the system. The single manifold is attached to the front side of the engine block.
Component Form: The manifold is a grooved 3’’x 1.5’’ elliptical prism, with a flat surface and sides, which is connected to an exhaust pipe. The pipe takes a 90 degree turn immediately after its attachment to the actual manifold which would then connect to the rest of the exhaust system. The purpose of the grooves is likely to expel heat from the part.
Manufacturing Methods: The actual manifold would likely be made via die casting. Clues to this are that it is a relatively small, mostly solid part. Component Complexity: 5 Flows: 1
Waste Gas
Energy: 1
Heat
Manufacturing Processes: 2
Casting, Milling
Functions: 1
Expel Exhaust
Subcomponents: 0
Gears
Gears Component Function
The main function of the gears inside of the transmission of the CBR 600 engine is to transfer power from one shaft to another in a specified gear ratio. The gears are arranged to mesh in certain ratio and to step through these ratios in a predicable fashion as chosen by the user, who changes them with a foot pedal on the motorcycle. The component functions in the environment of the transmission assembly, which is submerged in a pool of transmission fluid, which lowers friction ad reduces the buildup of heat, and helps disperse any heat that is generated by the action of the rotating gears. The flow of mechanical energy from the crankshaft to the output shaft flows through the gears and allows for the torque and rotation speed of the output shaft to be manipulated.
Component Form
The Gears are shaped like cylinders of various diameters, from Dimensions to … the depth of the gears is uniform, at … there are … gears and each functions with another gear in the transmission to form a specific gear ratio. The gears weight from … to … and are made of steel. The material of the gears must be strong and durable, and steel is both of these. None of the four factors apply to the material choice of the gears, economic factors may have a small part to play, as they could be a more expensive and durable material, but this would be too expensive and would not benefit the performace of the engine or bike. There is no aesthetic value to the silver color or the design of the gears, as they should not be able to be seen on a working motorcycle.
Manufacturing Methods
The gears of the engine are manufactured by hobbing, which is a form of machining. Hobbing uses a special drill bit that cuts the teeth of the gear into cylindrical piece of metal. Hobbing is the industry standard for making gears and is the most economical way to make uniform gears. Economic factors influenced the decision to hob the gears, as the gears could have been machined by a milling machine, but that would be expensive and not viable for mass production.
Component Complexity: 3
Number of functions:1
-Transfer mechanical energy
Manufacturing processes required:1
-Hobbing
Subcomponents:0
Flows associated with component:1
-Mechanical Energy from crankshaft to output shaft
Oil pan
Component Function
The oil pan serves as a holding bay for the oil which circulates throughout the engine. This oil lubricates the internal moving parts inside the engine and prevents a buildup of friction, as well as regulating temperatures. Oil flows in and out of the oil pan very quickly. The oil pump keeps oil circulating throughout the engine block and through the oil filter. The oil pan is the end collecting place for the oil. And where oil is drawn from by the oil pump. The oil pan is also the botton confining surface for the engine, and keeps the lower par of the engine from being exposed to outside contaminants.
Component Form
The oil pan is shaped roughly like a square pan or bowl with a flat bottom The oil pan is three dimensional, as it holds a volume of oil and has height width and depth. The pan is approximately Dimensions. The pans shape has everything to do with its function. The pan is shaped this way to allow for it to be the gathering place for oil in the engine, and allows for the oil pump to constantly be submerged with oil in order for the engine to operate. The oil pan is made of aluminum, which was chosen because of its relatively light weight compared to other metals and for its resistance to corrosion. The finish of the oil pan is that of the metal which has presumably been forged. The color of the oil pan Is a silver metallic color, and has little aesthetic value. The design of the oil pan is most likely all about function and was designed with little regard to aesthetics.
Manufacturing Methods
The oil pan was most likely forged. The geometry of the pan and its finish both indicate that the component was forged. The material choice of aluminum did have an effect on the choice of manufacturing methods, as aluminum is a metal and can be forged. The shape of the pan, with its drafted faces and shape with no undercuts allows it to be easily forged. Economic factors are perhaps the only factors that lead to the oil pan being forged, as if it was machined it would be much more expensive to produce with no gain in functionality or performance.
Component Complexity: 3
Number of functions:1
-Oil reservoir
Manufacturing processes required:1
-Forging
Subcomponents:0
Flows associated with component:1
-Oil to and from oil pump
Oil pump
Component Function
The oil pump delivers oil to the bearings, pistons and the camshaft. The oil pump delivers the oil directly to the joint between the crankshaft and connecting rod. the oil forms a fluid bearing and allows the two parts to move with little friction and no ball bearing to wear and add complexity to the system. The oil pump makes it possible for other parts of the engine to operate efficiently and with as little wear friction as possible. The oil pump consists of two rotors and rotor housing, as well as the shaft which powers the pump. The outer rotor has five teeth and the inner has four. This arrangement is the same as all gerotors, which have an inner rotor of N teeth and an outer of N+1 teeth. The inner rotor is driven by a chain which connects to the crankshaft and spins the outer rotor, creating a vacuum which sucks oil in from the oil pan and forcing oil into critical areas of the engine which require forced lubrication.
Component Form
The oil pump is a gerotor, which is short for a generated rotor. A gerotor consists of two rotors that intermesh to create a change in volume. On one side a vacuum is created and forces oil into the pump, towards the other side the oil must be forced out at pressure into the various components which are lubricated by the pump. The component is three dimensional and pressurizes volumes of oil in three dimensions. The pump is approximately Dimensions. The shape of the component allows it to serve its function in an efficient way and does not have any ornament or other aesthetic features on the part. The pump is approximately two pounds, and is made of steel and aluminum. The choice of material allows for the pump to operate under high loads and to withstand high pressures, these material properties are central to the operation of the oil pump and for the engine itself to operate. The component is silver in color and is not decorated in any way, any coloring is the result of machining and the metals natural appearance. The finish of the pump is fine and relates to the manufacturing of the product. The finish is functional and has the property of allowing for the pump to operate with low friction and to strict tolerances.
Manufacturing Methods
The oil pump is most likely machined. The rotors of the pump are manufactured separately from the pump and are made of aluminum. The pump housing is also made of aluminum and is also machined. The odd various right angles in the housing and rotors shows that the component was machined, and not forged. Aluminum is relatively easy to machine, which also supports that the component was machined. Economic factors were probably the only factors which forced the oil pump to be machined. The individual parts of the pump could be built in rapid prototyping machines but this would be uneconomical for anything but prototype parts.
Component Complexity: 9
Number of functions:1 -Pump oil Manufacturing processes:1 -Machining Subcomponents:5
-Top holding piece
-Inner rotor
-Outer rotor
-Bottom Holing Piece
-Connecting rod to Crankshaft
Flows associated with component:2
-Mechanical Energy
-Oil Flow [[[File:Water Pump26.jpg]]]
Pistons
Component Function
The piston assembly serves to harness the pressure generated by the ignition of gasoline into rotational mechanical energy in the crankshaft. The piston is pressed downwards by the ignited gasoline and air mixture, and this motion is translated into rotational energy via the pivoting connecting rod. Along with the engine block and head the piston forms the expansion chamber, where combustion occurs and the engine performs its function of producing energy. There are various flows associated with the piston, including flows inside of the expansion chamber and flows associated with lubrication. Pistons are central to the operation of the engine and without them the engine would not be able to function under its own power. The flow of the air/fuel mixture and the resulting exhaust gasses produced by the combustion of the air/fuel mixture produced inside of the combustion chamber is facilitated by the movement of the piston, as is the flow of energy from the buildup of pressure inside of the expansion chamber to the rotational movement of the crankshaft.
Component Form
The piston has two parts, the head and the connecting rod. the head is a cylindrical shape with a diameter of approximately 6.5 cm and a height of approximately 4.5 cm. Inside of the cylinder is largely empty, creating a cavity where the connecting rod is able to connect to the head. The head connects to the connecting rod with a press fitted cylinder of a length of approximately 5cm and a diameter of 1.6 cm. The connecting rod is approximately 12 cm long and connects the head of the piston to the crankshaft. The connecting rod makes it possible for the linear reciprocating motion of the head of the piston to transfer its energy into a rotating shaft. In order for this to be possible the materials which make up the piston must be durable, strong and hard. The head of the piston is made of Aluminum, and the Connecting rod is made of steel. All together the piston weighs approximately 1 pound. The design of the piston is 100% functional and does not have any aesthetic value. The piston is not colored in any way and retains the color of its material. The color changes with different finishes, and is predominantly silver in color, the finish is brighter in the parts which have tighter tolerances, and more subdued on the unfinished forged surfaces. The top of the head of the piston is colored black from carbon deposition, which is a byproduct of incomplete combustion within the engine.
Manufacturing Methods
The head of the piston is made of Aluminum which is forged them machined. The outside surface of the piston head must be cut to very strict tolerances, so that surface was probably machined to these tight tolerances. The connecting rod was also forged but is made of steel, and the surface where it interfaces with other parts is machined also. These machined surfaces are easy to see, as they have a smooth finish as opposed to the rougher pitted finish of the forged surfaces. Economic factors are the main facrots that relate to the manufacturing processed that were chosen for this component. The component is manufactured in the way which offers the correct tolerances needed for the cheapest cost. The noncritical surfaces are left with their forged loosely tolerance surfaces, while the tight tolerances needed where components interact were machined to create the correct level of tolerance and finish.
Component Complexity: 8
Number of functions:2
-Energy transfer(pressure to linear motion)
-Energy transfer(Linear to rotational motion)
Manufacturing processes required:2
-Forging
-Machining
Subcomponents:2
-Head
-Connecting Rod
Flows associated with component:2
-Chemical Energy
-Mechanical energy
Top Engine Block
Component Function
The top engine connects the bottom engine block to the head of the engine. Inside of it the block has the cylinders in which the pistons reciprocate in and which comprise the side walls of the expansion chamber. The top engine block also houses many cooling lines, which transport heat away from the cylinder walls, as the combustion of the fual/gas mixture produces large amounts of heat. The top engine block allows the engine to work, without it the engine would be unable to perform its function of producing power. The top engine block shield the expansion chamber from the outside environment and allows for combustion to occur. Flows that are associated with the top engine block are the flow of the air/fuel mixture to the expansion chamber, where the cylinders are located in the top engine block, and the transportation of heat energy to the cooling system on the bike.
Component Form
The form of the top engine block of the engine is roughly a rectangular prism shape, with four holes extending through the block and numerous cavities for the flow of coolant and weight reduction around these four central holes, attached to the side of this part of the block is another roughly rectangular prism shaped cavity which serves as the top cover of the transmission. This part of the block is a separate cavity than the part which houses the cylinders. Overall the size of the engine block is approximately Dimensions. The dividing line between the top and bottom portions of the engine block is where the crankshaft runs, and the top part of the engine block would interact with the crankshaft as the pistons reciprocate by holding it in place and allowing for the translation of the reciprocating linear motion of the pistons to the rotational energy of the crankshaft. The top engine block is made of aluminum and is forged and machined. The choice of aluminum was made to reduce weight, being a motorcycle engine weight must be saved at each step of the manufacturing process. Aluminum is also strong and durable, making it the perfect choice for the material which the top engine block is made of. There are no aesthetic properties considered in the design of the top engine block the color of the component is silver and the finish visible to an outside observer is a smooth metal finish typical of forged parts. The design of the engine did not emphasisze aesthetics in the least bit, as the engine is designed to be as efficient and economical as possible.
Manufacturing Methods
The top engine blick is forged and machined. The overall shape of the block and most of the surfaces are forged, any surfaces that require tighter tolerances, such as the cylinders or the top and bottom surfaces of the block which connect to other parts of the engine were machined to create surfaces which are free of any major pitting or defects. The material of the top engine block is aluminum, this metal is light, strong and easy to machine. The choice of aluminum cuts down on weight and allows for easy machining, saving money and making the engine lighter. The shape of the top block was designed to be easily manufactured. The block is designed to have no undercuts and has shallow drafts on its vertical faces to make it easily forgeable. From there the tightly toleranced surfaces were then machined to exact specifications. Economic factors are central to the manufacturing of the top engine block. The choice of forging the component before machining it saves a large amount of money and material than if the top engine block were to be fully machined. Other factors were not considered when designing the top engine block of the engine.
Component Complexity: 8
Number of functions:3
-Houses expansion chamber
-Cooling
-Holds crankshaft in place
Manufacturing processes required:2
-Forging
-Machining
Subcomponents:
-
Flows associated with component:3
-Heat
-Mechanical energy
-Chemical energy
Radiator hose
Component function- The radiator hose is a small component of the radiator, which is used to cool an internal combustion engine. The radiator operates by passing a heated water based coolant throughout the engine block, via the radiator hose, which absorbs excess heat from the engine and expels it to the atmosphere. The radiator hose has a flow of coolant which passes through it, as well as the thermal energy which is transferred from the engine to the coolant.
Component form- The radiator hose is exactly what you would expect it to be, a long, thin tube, which fits its function perfectly, as it can pass coolant all through the engine, without being significantly sizable or massive. These hoses are generally made from a rubber polymer, which leads to one very important design consideration, which is that the material used can resist high temperatures, as the amount of heat the hose will encounter is substantial. This consideration would fall in the category of economic factors, as a rubber hose would be much easier to replace if it ruptures, and also would be a cheaper fix. The radiator as a whole is a major safety factor in the engine, as it keeps it from overheating, which can be very dangerous. This consideration can be labeled as societal, as it gives the bike a new level of safety, which makes it more appealing to consumers. The radiator does not serve any aesthetic purposes, but is rather primarily functional, as it is not seen throughout normal usage, unless the engine is taken apart. It is merely a black rubber hose, with a rough finish, but any improvements to the finish would be an unnecessary cost.
Manufacturing methods- Radiator hoses are made through the process of extrusion, where they are heated and then forced into a mold, and then taken out and cooled after the desired shape is acquired. Most wire and hose like products are made this way, as it is the easiest and most convenient way to create their shape, and to do it quickly. Obviously, the most important consideration in this process would be economic, as extrusion is a cheap manufacturing process for making small parts such as a hose.
Component complexity
# of functions- 1, move coolant
Manufacturing required- 1, simple extrusion
Flows associated- 2, mass of coolant, thermal energy
Subcomponents- 0, none
Shifter cam
Component function- The shifter cam in this engines main function is to turn rotational motion about its axis into linear movement of another component. In this case, the cam controls the intake and exhaust valves on the cylinders. This allows them to be operated without the use of a linear force, but rather uses the force from a rotating component that would exist anyway. The shifter cam translates the supplied shaft work to mechanical energy moving the valves. It is located alongside the gearshift assembly, near the clutch.
Component form- The shifter can is a 6 pointed shape, with axial symmetry, as it must spin about its axis on the driveshaft. The reason for its shape is to provide a perpetuating linear force on the valves, forcing them closed and then allowing them to open. It is a metal part, likely made by simple casting, which would give it its unique shape. As is with most components in the engine, the shifter cam has no aesthetic qualities, as it is not seen through regular use, but is hidden amidst the engine unless it is disassembled. Since it is made through casting, the surface finish is not very fine, but this is negligible in its function, making the part cheaper and therefore and economic consideration.
Manufacturing methods- As previously stated, the shifter cam is made through a die casting manufacturing process, which is essentially liquid metal forced into a cast, which is then allowed to cool and take its shape. Since the cam has a rather simple geometric shape, casting would be the ideal process, which allows a large quantity of products to be manufactured in the least amount of time.
Component complexity
# of functions- 1, open and close valves
Manufacturing required- 1, die casting
Flows associated- 1, shaft work to linear work
Subcomponents- None
Spark plugs
Component function- Spark plugs, which are housed in the cylinder head of the engine, is used to ignites the fuel and air mixture with an electric spark, and thereby burn the fuel. Although this is the only function a spark plug performs, it is quite crucial to the inner workings of an internal combustion engine, as without properly working spark plugs, the engine will not turn over. The only flow associated with the spark plugs is that of an electrical energy flow, which is turned into thermal energy, causing combustion of the fuel.
Component form- A general spark plug looks quite similar to a very small light bulb, the difference being that it is used to supply electricity, not turn it into light. Spark plugs are axially symmetric, which shows that they may be made through a turning process, and also aids the functionality, as the thread which turning creates allows the plug to be securely placed inside the head. The electrode of the spark plug is made primarily of copper, nickel or other noble metals, and the casing which acts as an insulator, surrounding the electrode is made of a ceramic material. The metal used for the electrode is actually a significant consideration during manufacturing, as metals which cannot take the amount of heat experienced are likely to melt, and those that run too cold will cause an engine to misfire, so it has been determined through much testing that copper was the best material to accomplish this task. This would be classified as an economic consideration, as faulty spark plugs which often misfired would become an inconvenient expense for owners. Once again, spark plugs are a component which are entirely functional, and do not have any significant aesthetics aspects. However, the surface finish on the thread of the spark plug is quite fine, as it needs to very accurate, or it would not mesh, and therefore not fit effectively within the cylinder head.
Manufacturing methods- Spark plugs are composed of three main parts, the shell, the insulator, and the electrode, and each require a specific process to manufacture. The shell is first extruded to acquire its general shape, and then is shaped through the process of knurling, which creates the contours on the outside of the shell. The insulators are molded and then attached to the shell, and a hole is bored in the top for the center electrode to be fitted. The electrode is welded to a basic steel terminal, and then attached to an ignition cable inside the plug, and the part is completely assembled. The processes of extruding and casting represent economic considerations, as they are generally cheap processes, which are best for mass production of products.
Component complexity
# of functions- 1, spark fuel
Manufacturing required- 3, extrusion, molding, knurling
Flows associated- 1, electric to thermal energy
Subcomponents- 3, shell, insulator, electrode
Starter motor
Component function- The main function of the starter motor is to aid the staring of an engine, so it can quickly begin functioning through the use of its own power. Essentially, the starter motor is initially connected to the driveshaft and flywheel, and gets them in motion. As soon as the engine starts, the motor is disconnected, and the engine begins to run on its own. If the motor were to stay connected, the speed of the driveshaft would destroy the motor, as it cannot take such torque. The motor uses a flow of electric energy to create shaft work about the driveshaft, impending motion and causing the engine to turn over. Starter motors are housed on top of the engine block, adjacent to the driveshaft.
Component form- The starter motor is a small, cylinder, with axial symmetry, which is quite heavy for its size, due to the fact that it in itself has many components. The motor is composed of a clutch, gear assembly, armature, coils, and solenoid, all inside its main housing. The materials used are mainly metallic, as the material needs to be able to take a substantial amount of strain from spinning of the driveshaft. The embedded solenoid carries a large current which is turned into mechanical energy, so the solenoid needs to be made of a strong conductor, preventing any extra power loss at this stage. This would be classified as a primarily economic consideration, as a poor conductor used in the solenoid would lose energy, and therefore would require more input to get the same amount of output. The starter motor is embedded in between the cylinder head and engine block, so it is not seen by a user unless they themselves disassemble the engine. Therefore, the starter motor does not have any aesthetic qualities, but is rather completely functional.
Manufacturing methods- The casing of the starter motor can be formed entirely from casting, which would be the most cheap and efficient process. However, the other components would require a more accurate manufacturing process, as they need to be very accurate to function properly. For this reason, the clutch and armature would require milling to make sure the finish is as accurate as possible. Clearly, these are both economic considerations as with the casing you are applying the cheapest process, and milling on the clutch and armature would prevent any simple errors due to incorrect dimensioning that could prove to be quite costly, most likely resulting in a total replacement of the motor.
Component complexity
# of functions- 1, begin turning of driveshaft
Manufacturing required- 4, molding, milling
Flows associated- 1, electric to shaft work
Subcomponents- 5, clutch, gear assembly, armature, solenoid, field coils
Product Analysis
Solid Model Assembly
3D modeling program: Google Sketchup
Our Choice to use Google Sketchup as our 3D modeling program was made upon surveying the group for a capable 3D modeler. One member of our group had extensive experience with Sketchup and was willing to model up the needed parts. Sketchup is also a free and easy to user program, which made it easy for each member of the group to look at the part files on their own computers and for the images to be exported to a format which is compatible with the wiki.
Camshaft
The camshaft was modeled to show the process of valve system. this shaft pushes the poppet valves of the engine open and closing using the humps on the shaft. These humps are called cams, and push the valves and precise intervals to run the engine properly.
Crankshaft
The crankshaft was modeled to show how the engine transfers the linear reciprocating motion of the pistons to the rotation motion of the output shaft. the crankshafts design allows for this to happen effienctly and with little vibration.
Water Pump
The water pump was modeled because of its complexity and importance in the engine. coolant is circulated throughout the engine by the water pump, and this transfer of heat energy allows for the engine to run at a safe and reliable temperature.
Engineering Analysis
An important factor that goes into the testing of any combustion engine is the efficiency of the engine. Especially under our current economic stance on usage of fossil fuels, the amount of fuel used in any engine is sought to be as low as possible. For this reason, engineers spend much of their time figuring out how to make any engine more efficient. However, even with all this research, internal combustion engines still experience massive power losses, the average efficiency only being 25-30%. Testing the exact efficiency at first seems like a difficult process, as there are many variables which come into play. One would start their analysis by finding any given values about the engine and its components that would be needed, like gear sizes, and also some specifics of the gasoline. You would then account for all flows going into the engine, and all flows exiting. When this is done, it can be seen that this comes down to a simple equation which relates input energy to output energy. The energy going into the engine is provided by the fuel, and that is converted to mechanical energy through the combustion process. The energy output, which is significantly less, is in the form of shaft work, which would the turn the engine, and begin its function. Next, the equations that will be used to solve the problem are listed, and they are as follows:
Ein=ṁgas*ρgas
Eout=Ẇshaft=2π*ω*τshaft
Eff=Eout/Ein*100
These equations encompass all values we would use or find throughout the calculations, and once we arrive at an answer, it is important to check it to make sure no errors were made, and the data is credible. The final step for any engineer would be to relay this information to those not as well fluent in the language of engineering, and explain the significance of this value.
Design Revisions
Fuel Injection
The first change would be to replace the carburetors with fuel injection. Instead of relying on small openings and pressure zones to mix the fuel and air, the injection system would atomize the fuel and “spray” in exact portions into the piston chamber using a computerized system. This would increase the cost of the engine but improve its performance, efficiency and reliability.
Advantages:
More complete fuel burn: A fuel injection system atomized the fuel as it injects it into the expansion chamber. This allows the fuel to more completely and efficiently burn. A fuel injection system allows for a more precise release of the gasoline into the chamber, and thus allows the engine to run a leaner mixture. using a leaner mixture means that less fuel is needed to run the engine while still producing the same amount of power. The increased efficiency would address both economic and environmental factors, as the engine would pollute less, and get better gas mileage which would lessen the amount of money the end user must spend on fuel.
Better throttle response: Fuel injected engines benefit from a more immediate throttle response than a carburated engine. The fuel injected engine would more readily and immediately respond to the users commands than a carburated engine. this addresses the societal factor of usability and product feel, as the user would feel a noticeable difference in response from the engine. This impacts societal conciderations because it affects the response of the bike to the user.
Easier starting: There is no choke in a fuel injected engine and they are nearly impossible to flood. A fuel injected engine would also be be much easier to start in all weather conditions than a carbeurated engine which inpacts the engine societal factors of the bike because it increases the user friendlines of the engine. This also related to overall better operation over a wider temperature range which impacts the engine design globally because the engine can work in a greater range of climates and geographic areas.
Disadvantages:
Ease of service: The downside to a computer controlled machine is that a breakdown can no longer be fixed with simple tools, and the ability to “tinker” with the bike is decreased. Carburators are much simpler than fuel injection systems and can be easily adjusted by an owner with a service manual.(economical because of repair costs)
Higher initial cost: A fuel injection system would be more expensive to include on an engine than carburetors. The advanced technology is built to stricter tolerances and uses computerized components that are more complex to make and require more manufacturing processes and more in depth development.
Five Valves per Cylinder
Adding an additional intake valve to each cylinder of the engine.
Advantages:
More Power: An additional intake valve would allow for additional fuel to be relseased into the expansion chamber, and would increase the amount of turbulence in the chamber, which increases the dispersion of the fuel. The additional fuel would provide the engine with additional cranking power. This advantage addresses the societal factor of the user experience. The additional power would be noticed by a rider and would make the bike more desirable than a similar four valve per cylinder engined bike.
Higher Max RPM: As each valve would be smaller than in a similar sized four valve engine the valves would be able to open and close more easily and would not be as susceptible to valve float and other limiting factors to high engine speeds that engines with fewer valves per cylinder are susceptible to. A higher maximum RPM would address the societal factor of user feel, as the end user would have a wider range of usable engine speeds which would be usable.
Disadvantages:
Cost: Additional manufacturing processes would need to be added to incorporate an additional valve to each cylinder, and additional parts would need to be machined, such as the extra valve and the port which it would be inserted into. This is an economic factor, as the engine would probably cost more initially for the end user.
Added Complexity: An additional valve in each cylinder could also be looked at as an additional component to fail in an engine, and would make repairs more expensive if something were to go wrong in the engine. Adding another level of complexity also increases the cost of rebuilding the engine, as replacing valves would cost more because of the additional parts. This addresses both the societal factor of serviceability and the economic factor of increased service cost, although service would not be needed as often as a similarly set up carburated engine.
Addition of Catalytic Converter
In its present state the engine does not have a catalytic converter, and exhaust gasses are released into the atmosphere untreated, full of noxious, polluting chemicals. Adding a catalytic converter would greatly reduce the negative emissions released by the bike.
Advantage:
Lower Emissions: Catalytic converters drastically reduce hydrocarbon, carbon monoxide and nitrous oxide emissions. Each of these is a pollutant that negatively impacts the environment. This addresses environmental factors, as the lowered emissions of the engine due to the catalytic converter would make the engine much more environmentally friendly.
Disadvantages:
Cost: Adding a catalytic converter would be an additional component on the engine, and would add additional manufacturing processes to its assembly. While it would be a one time investment, this cost would be transferred to the user, and would be considered as an additonal economic factor for this engine.
Reference url’s: http://www.cbrextreme.com/specs/1994/CBR600F2/ http://articles.latimes.com/
2008/jun/11/autos/hy-throttle11
