Group 5 - Kawasaki Compressor 2 Gate 2

Introduction

Referring to the Gantt Chart as shown in Gate 1, the submission of Gate 2 marks the completion of the dissection of the Kawasaki Air Compressor. This gate can be divided into three general parts: the cause for corrective action (which falls under group and project management), the physical dissection procedure, and the subsequent analysis of the subsystems found to compose the air compressor. Please use the contents to navigate through various parts of the page.

Cause for Corrective Action

Thus far, we have found our work and management plans to be quite successful in fulfilling their task. During the dissection, we followed the steps that we outlined in our work plan almost exactly, although there was obviously a little more detail involved within the parts that we could not examine without the dissection of at least a portion of the system. The only additions to our tool list were two Flathead screwdrivers, which were used assist us in overcoming one challenge that we encountered, prying the protective metal cover off of the motor. This task was crucial to the completion of the product's dissection because it allowed us to separate the motor from the crank case. Please refer to the Product Dissection section for further detail on the process. As for the management plan, we have found that our group roles were assigned to meet our strengths and weaknesses appropriately. Each member settled into their role quite quickly and has been fulfilling their corresponding responsibilities. Our conflict resolution plan has been in place but has yet to be utilized, most likely due to the high level of respect that we have for the given parameters and the seriousness with which we are treating it. Because of the success of said plan, we have avoided any potential challenges regarding the teamwork of our group or our ability to complete our given tasks in a timely fashion.

One aspect of our work plan that could potentially pose a problem for us is our designated times for meeting. We currently have a flexible scheduling plan in place, by which we schedule meetings on a week by week basis. Our meetings fall on different days and times based on the schedules of each individual in our group for each given week. So far, this has worked fairly well considering that on only one occasion was a single member not able to attend a group meeting. However, communication among the group as a whole has not always been the easiest thing to accomplish. Some of our group seems to rely heavily on email as the main medium of communication, but others prefer cell phone calls and texts because they do not regularly check their email. This inconsistency has, on occasion, led to a slight delay in the finalization of plans and an adjustment of the expected deadlines for the completion of some subtasks. To address this potential problem, our group will, at our next meeting, discuss how we will adjust our current communication methods to better suit the group as a whole.

Product Archeology

Product Dissection

The dissection of the eight gallon Kawasaki air compressor took approximately two and a half hours to complete. In order to quantify each step of the disassembly process, a subjectively determined ordinal scale ranging from one to five was created. One represents a task requiring the minimum amount of effort and time to complete. Two corresponds to the parts that make up this component being fairly simple however; disassembly may require tools or machinery. Three represents individual parts that require more detail to remove. The component may be difficult to disassemble and requires some experience, Four is equivalent to involved steps and proper techniques that are necessary to remove this component. This may require a considerably greater amount of time than the previous steps. While five represents the most complex task requiring a majority of the time of the total dissection as well as a wide array of tools.

Table 1: Product Dissection

Picture	Steps	Difficulty Rating
Removal of Shell	Step One: Remove plastic shell which covers the piston housing and motor. -This task required removal of four screws with one Philips head screw driver. -Once screws were removed the shell has to be lifted from the unit to complete this step.	-(1)The difficulty rating for this step is a one because of the simplicity of the required actions. This step took no more than five minutes to complete.
Separation of Metal Housing from Air Tank	Step Two: Separation of the metal housing from the air tank. -First the copper hose, connecting the piston housing to the air tank, was removed with a three-quarter inch wrench. The wrench was placed around the nut and rotated counter clockwise with a substantial force. -Next we disconnected the smaller copper tube that connected the pressure regulator to the crank case. This required a rotational force exerted on the nut through the use of a thirteen millimeter wrench. -Then, the pressure regulator was disconnected from the tank. Once again rotational force was required through means of a seven-eighths inch wrench. - Finally, the last component connecting the metal housing was four bolts attached at the bottom of the housing above the tank. These bolts were removed using a thirteen millimeter wrench holding the nut and a twelve millimeter socket wrench to unscrew the bolt.	-(3)This step is a three on our difficulty scale. This rating is appropriate for this task because the components were easy to remove but required a decent portion of time (about 30 minutes).
Removal of Rubber Stoppers, Wheels, and Handle Bars	Step Three: Removal of rubber stoppers, wheels, and handle bars. -To take off the rubber stoppers we used a fourteen millimeter wrench in counterclockwise rotational motion to separate the bolt, nut, and washer. -Next we disassembled the wheels using an eleven-sixteenth inch wrench removing the same components found in the rubber stoppers from the bracket on the bottom of the tank. As stated earlier this process also utilized rotational force. -Finally, we detached the handle bars from the tank using a four millimeter allenwrench to unscrew four hex screws.	-(1)These tasks correspond to a difficulty rating of one as a result of the minimal work and five minutes needed to complete this stage of disassembly.
Disassembly of Piston Housing	Step Four: Disassembly of the piston housing and fan. -Four bolts located on the top of the piston housing connected to the crank case were extracted using a twelve millimeter socket wrench. The socket wrench was turned counterclockwise to free the top plate of the housing. -The fan located at the rear of the motor was detached via a five millimeter allenwrench and flathead screw drivers to pry off a small malleable clip.	-(4)The difficulty rating of this step is a four because we experienced a problem removing the fan from the motor. We had to reevaluate our method and devise another solution. This step ended up taking about 35 minutes instead of the 20 it should have taken without complications.
Exposing the Crankshaft	Step Five: Exposing the crankshaft and removing the piston. -We used a four millimeter allenwrench to remove six hex screws from the back of the crank case. This section of the crank case would normally be filled with oil but it had already been drained. We know this because this section contained a gasket to prevent leaks. This exposed the crankshaft. After further analysis and input from the T.A. we arrived at the conclusion that the crankshaft did not need to be further deconstructed because all components were visible. Since this part of the crankshaft case was removed the piston was slid off the crankshaft.	-(3)This phase of deconstruction required a more elaborate analysis of which parts were necessary to remove from the system as opposed to inessential decomposition. This increased the time for the task to 30 minutes, but they were still simplistic so the difficulty rating for this stage is a three.
Motor	Step Six: Motor and capacitor separation and motor analysis. -First we used a Philips head screwdriver to remove small screw from the capacitor, and then removed the capacitor itself from the crank case. -Then we utilized an eight millimeter wrench to disconnect the four rods going through the motor housing to the crank case. -Lastly, we used two flat head screwdrivers to pry the protective cover off of the motor, allowing the motor to then slide off of the crank case. -From this complete separation of the motor from the crank case we established that we could not breakdown the motor any further while still being able to reconstruct it. It was not necessary to deconstruct any further because all components of the motor were visible.	-(4)This difficulty rating is a four because of the multiple approaches that failed to disconnect the motor from the crank case. This step consumed about 45 minutes of our dissection time.

Products Not Intended for Disassembly

The components of the air compressor that can be conclusively determined to have been manufactured with the intent that they never see disassembly by the consumer are the pressure gauges, the motor’s electrical wiring, all connections to and from the storage tank, and the storage tank itself. The gauges are delicate, but their function is integral to the proper operation of the product. The gauge housing is intentionally difficult to remove. The motor’s electrical wiring is too complex for most consumers to properly service. All connections to and from the storage tank are either welded in place or sealed with a compound. The tank itself is welded together and any whole or partial disassembly would impact the potential integrity upon reassembly.

Subsystems Analysis

In the following section, the subsystems of the air compressor are defined, along with the nature of their interactions and other important details. The goal of this section is to understand how the subsystems are connected, why they are connected, how these connections are implemented, and why they are arranged in any particular manner.

Definition of Subsystems

Figure 1: Placement of Subsystems

Before entering a detailed discussion on the air compressor’s subsystems, it would help to first define them. Each numbered arrow on the picture corresponds to the system defined below:

1. The first subsystem is the air intake system. This is defined by the externally placed air filter, which has a direct connection to the inside of the piston chamber.
2. The piston chamber is another subsystem defined by the piston, the piston cylinder, and the air inlet and air discharge ports.
3. Another subsystem is the crankshaft (as a single entity).
4. Then there is the electric motor, which in it of itself is an independent subsystem.
5. The electric motor is closely associated to the power input subsystem, which entails the wall outlet plug, the start capacitor, the circuit breaker and reset switch, and all electrical wiring connecting these parts and the electric motor.
6. The air storage subsystem is defined by the air storage tank. Attached to said tank is the appendages subsystem, consisting of the handlebar, the wheels, and the rubber supports beneath the tank.
7. Next is the air transport subsystem, which includes the metal hoses which connect the piston chamber to the air storage tank and the air storage tank to the pressure regulator (also referred to as “the regulator”), and the black synthetic tubing which exports the final pressurized air product to be used.
8. Finally, the regulator (8) and the fan (9) are each two independent subsystems, which will be referred to in the ensuing discussion.

Subsystem Pairs

In the ensuing discussion, the subsystems as defined above are analyzed in pairs to address the questions of how subsystems are connected, why they are connected, how such connections are implemented, and related questions. Now that definition of each subsystem has been established, the types of connections between each of the subsystems can be further discussed.

Air Intake and Piston Chamber Subsystem Connection

The air intake system is connected to the piston chamber subsystem by physical and mass means. The air filter is screwed into the piston housing which defines their physical connection. The mass connection is embodied by the air that flows through the air filter, which then enters the piston housing via the opening of the air inlet valve. The reason for this connection should be evident, as the piston chamber requires air to be input into the system that will be compressed and ultimately helps make the final output of the product (highly pressurized air). As alluded to above, the connection between the air intake and piston chamber subsystems is implemented by a threaded hole in the piston chamber, into which the air filter is screwed. Performance characteristics here are important, as the air filter should be screwed into the piston chamber tightly enough that it is secure at all times during operation (the stress and strain demands on the connection will significantly increase when the piston is in peak operation), but it should be loose enough that it can be unscrewed by hand in order to replace the air filter. As is the case with many subsystem interactions in the air compressor, the most important factor considered for this connection is economic, as the usage of higher performing yet ultimately unnecessary parts for this particular product envelope will adversely affect cost—a major consideration in the design of this or any product. Reinforcing the economic concern in addition to societal and environmental, synthetic materials are used in the air filter piece, as using metal would be more expensive, more abusive to the earth, and puts the labor behind creating that piece at a relatively higher risk (i.e. mining for metal vs. creating chemical composites at a factory).

Piston Chamber and Crankshaft Subsystem Connection

The next connection pair to analyze is the piston chamber subsystem and the crankshaft subsystem. This is a physical and energy connection. The physical connection is provided by the connecting rod, which on one end slips onto the crankshaft and on the other end is attached to the piston head. The energy connection is more abstract. The crankshaft carries kinetic energy by virtue of its rotational motion, which is transmitted to the piston by the connecting rod, allowing for its vertical motion. This connection is vital to the higher function of compressing air, because in order for air to be imported into the system and compressed, the piston must be moved along its linear path within the piston cylinder. The only way that this can feasibly be accomplished is via the kinetic energy of the crankshaft. However, because the crankshaft moves in a rotational motion, the connecting rod must be implemented to translate it to the linear motion required by the piston head. This connection is actually influenced by the global and societal concern of utilizing energy. A huge percentage of societies on Earth utilize energy, whether it is chemical or electrical, via a connection similar to this one because this type of connection is frequently used to harness the power of engines. Economic and environmental concerns are considered as well, as this connection is one of the most efficient ways known to translate energy that is rotational to linear, or vice versa, when converting electrical (or chemical) energy to kinetic mechanical energy in a mobile unit. As with every subsystem connection, this one is crucial to the higher function of the system. When performance is considered, there is not much flexibility in terms of what materials can be used for the connection. They obviously must be highly reliable, durable, stiff, and able to handle fast, forceful motion. This is why a metal alloy fitting all of these characteristics was chosen for the crankshaft, connecting rod, and the piston itself.

Crankshaft and Electric Motor Subsystem Connection

To describe the connection between the electric motor and the crankshaft subsystems, it is helpful to analyze how these subsystems interact while in operation. Current passes through the coiled electrical wiring in the motor, which then produces a moving magnetic field that causes the crankshaft to rotate. Though there is no physical connection, the net effect is to convert electrical energy to the kinetic energy in the crankshaft. The connection is made in this way due to the fact that the continuous motion of the piston is dependent upon a maintained motion of the crankshaft as facilitated by the motor. This is unlike a gasoline engine in which the combustion in the piston chamber facilitates the rotation of the crankshaft. There is still more that can be said concerning the connection’s implementation. The electrical power is sent to the coated wires in the motor and, through a method of induction, causes the shaft to which the crankshaft is connected to rotate. The crankshaft then translates this rotation into a reciprocating linear motion. Conforming to societal, economic, and environmental pressures, this part of the product is assembled from relatively inexpensive and abundant substances which bear little burden on the consumer’s conscience or wallet. Performance demands are such that the necessary power requirements of the crankshaft subsystem and piston subsystem can be sufficiently met by an electrical supply instead of a conventional belt system.

Electric Motor and Power Input Subsystem Connection

The electric motor is connected to the power input subsystem by one fundamental connection type that embodies a physical, signal, and energy connection. Essentially, the power input system is connected to the electric motor system via copper wiring, that carries electric current from a wall outlet (and the start capacitor—if the motor is in the process of starting up) to the electric motor. The wiring is an evident physical connection, but the current that the wiring carries while active also describes a signal connection (the current itself) and an energy connection (the electrical energy embodied by the current that allows the motor to output its electrical input into the rotational kinetic energy of the crankshaft). The reason for this connection is obvious—the electric motor needs some sort of electric power input in the form of electric current in order to serve its function (discussed in the electric motor and crankshaft subsystems paragraph). As for how these connections are implemented, the physical wiring is of copper metal that is tightly wrapped in synthetic insulation. This insulation varies in grade, as a thicker and tougher composite material is used in the wiring directly surrounding the electric motor (as opposed to the relatively thinner insulation that is used for the wiring surrounding the capacitor). The reason why copper is used as the medium for the wiring is clear. Copper is highly conductive material that is in relatively abundant supply (from mining and recycling of old appliances, etc), and is relatively cheaper than some of the other conductive materials used in other electronic devices. The low resistivity address performance concerns, while the relatively low prices and recyclability addresses economic and environmental concerns. Since the wiring is buried beneath the surrounding structure of the air compressor, the choice of wiring material is not heavily affected by societal concerns (although it should be noted that copper is readily available domestically, unlike some rare-earth metals required for higher-end devices such as cell phones and laptops, which must be obtained from politically unstable parts of the world). Synthetic material is utilized for insulation for equally evident reasons, as the name “synthetic” implies the advantages—that is, it is man-made, and thus it can be created in a cheap manner that meets desired performance needs, as opposed mining natural materials, which can be expensive, and not yield desired performance specifications. Cognizant of performance demands, the insulation becomes thicker and more durable in the area surrounding the electric motor, due to the moving parts in the motor and the need to keep the rest of the metallic structure protected from the electric input current (otherwise poor consumer reviews should be expected). If this thicker, more durable insulation was used for all wiring in the air compressor, it would cause material costs to increase. In engineering, one is always looking for the most economic solution to meeting minimum required performance demands, and that is evident in the case of the air compressor’s electrical wiring.

Air Transport and Pressure Regulator Subsystem Connection

The connections between the air transport and pressure regulator subsystems are physical as made clear by the observation of the metal tubing of the air transport subsystem entering and exiting the plastic housing in which the regulator is contained. This connection also consists of a transfer of energy, mass, and signal, which can be inferred from some knowledge of how the overall system (the air compressor) functions. The mass aspect of the connection is simply the mass of the air that is passing though the tubing, into, and out of the regulator. The air is moving quickly and is compressed at a high level, which implies that it is rich in both kinetic and potential energy. As the air is transported, the energy is transported as well, and once it reaches the regulator this energy is monitored, to some extent, by the measurement of pressure. Since the regulator subsystem essentially controls whether or not the overall system continues to compress air, a signal is, in a way, transmitted from to air transport system to the regulator. This signal is quite simple in nature: the pressure of the air in the tubes is at the desired level, or is below the desired level. The transmission of said signal is the main reason these two subsystems are connected because without it, the overall system would have to operate in a manner that was either highly inefficient, unsafe, or both. Lacking the connection and transmitting signal encompassed in the connection would result in the motor constantly running, since the regulator would essentially have no function due to the fact that it would not know when to make the motor cease action. This would be incredibly energy inefficient, especially if the compressed air was being utilized in a manner that was intermittent or slow. In addition, the constant functioning of the motor would likely lead to a large buildup in air pressure within the air storage tank, creating an unsafe situation for the user. It is also important to note that the connection between these subsystems must be the air transport subsystem’s final connection prior to being utilized. This specific arrangement allows the regulator to assess the air pressure that is being stored in the tank, and gives the user the ability to limit the pressure of the air being output. The air transport and regulator subsystem connection is designed with economic concerns in mind because it not only is composed of widely available materials such as plastic and copper alloy, but the connection’s overall function allows the regulator to know when a sufficient level of pressure has been reached within the storage tank. As a result, the regulator can stop the engine from consuming high levels of electricity when it is unnecessary, effectively saving the consumer money. This point is further discussed in the power input and regulator subsystems connection. In addition, the signal portion of the connection between the air tubing and the regulator allows the overall system (the air compressor) to abide by safety standards, a concern that is very much global. As already discussed, if the system was unable to limit the pressure of the air in its storage tank, it would propose a large safety hazard to the user and anyone else in the vicinity of the system. While the performance of this is connection is very important to the higher system, it can be accomplished in a way that is relatively inexpensive, using materials that are widely produced. One important thing to note is that metal tubing is used for the transport of the air to the regulator. This is most likely more than just due to the fact that the air is compressed at a high pressure, but also because the use of metal helps to protect and ensure longevity of the connection. On the other hand, plastic was chosen as the regulator housing, probably because it is capable of sufficiently protecting the regulator and is cheaper than metal.

Energy Input and Pressure Regulator Subsystem Connection

Yet another clear connection between subsystems is that of the pressure regulator and the power input subsystems, as the black insulated wire of the power supply passes directly through the plastic regulator housing. This is a connection of physical, energy, and signal means. Once the inside of the housing is observed, it can be seen that the wiring is physically hooked up directly to and from the regulator. This connection gives the regulator the functional ability and the electric power necessary to control whether or not the power input system continues to supply energy to the electric motor, effectively dictating when the compressor is actually compressing air. The supply of energy to the regulator itself, and the flow of energy into and out of the regulator (providing that the pressure in the tank is such that the regulator is allowing power to continue flowing out of it) constitute the energy portion of the connection. In terms of a signal connection, simply plugging the outlet plug into a socket sends a signal to the regulator “telling” it to evaluate the pressure within the tank and “decide” whether or not to forward the electric energy onward to begin powering the motor. The placement of this connection prior to the power input and electric motor subsystems’ connection, in the order of the flow of electric power, is essential for this reason. The decision made by the regulator is in correspondence to the signal relayed by the air transport and regulator subsystem connection. If the signal is that the pressure is below the desired pressure, the regulator senses this and continues to allow the electric power to flow to the motor. If the signal is that the pressure is at the desired level, then the regulator will sense this and react by impeding the flow of electricity to the motor. This connection is crucial in preventing the potential problems assessed in the Air Transport and Pressure Regulator Subsystem Connection (motor running constantly, energy inefficiency, and overall safety), and presents a convenient means of doing so. The prevention of said problems is done with the three following concerns in mind: the global concern of safety (for explanation see the Air Transport and Pressure Regulator Subsystem Connection section), the economic concern of saving money by decreasing electricity use, and the environment concern of conserving the resources used to produce electricity. Also, because a majority of the means by which electricity is produced is harmful to the environment, the connection’s ability to limit the amount of electricity needed for the system to perform its function is also environmentally friendly. The performance of this connection is absolutely necessary for reasons already discussed, but in order for a high level of performance to be reached, there is not much of a resulting increase in price. Copper alloy is most likely what is used throughout the power input subsystem, which is widely available and reasonably priced. This material is also used to constitute the physical connection between the two subsystems. As far as the regulator is concerned, its material makeup is cheap as well, consisting of a plastic protective shell, and a metal alloy lever and gears.

Piston Chamber and Air Transport Subsystem Connection

The piston subsystem shares two connections with the air transport subsystem. The first being the physical connection of the tubes, and the second being the flowing mass of air between the two subsystems. The connection between these two subsystems is necessitated by the need to export the compressed air from the piston chamber and eventually into the storage tank. Air that has been imported into the piston chamber is compressed by the moving piston that acts to decrease the volume of the chamber while it contains a constant mass of air. A valve is then open allowing the compressed air to leave the chamber through the discharge port. From there, it is directed through the tubes that comprise the air transport subsystem and towards the storage tank. From environmental and economic perspectives on the construction of the compressor, the use of copper and other alloys that are in abundant supply both lowers expected cost to the consumer and poses the least possible impact on the environment. The intended performance constraints of the compressor have the greatest influence on the choice of valve system in the piston chamber. The valves used are plate-like and are engaged by either positive or negative pressure in the piston chamber relative to the pressure outside the chamber. This is unlike the valve and cam designs of larger or more sophisticated engines.

Air Transport and Air Storage Subsystem Connection

The air transport and air storage subsystems share a physical, mass, and energy connection. The part of the air transport system involved here is the metal hosing that originates from the piston chamber (explained in further detail in the piston chamber and air transport connection paragraph) that leads to metal elbow connector with three connections—one with the metal hose from piston chamber, one directly with the air storage tank, and a final connection with the metal hose that leads to the regulator. This elbow connector (in particular the cross-sectional boundaries between the metal hose and connector and the connector and air storage tank) is what forms the connection between this part of the air transport subsystem and the air storage subsystem. The elbow connector itself is mounted on the air storage tank in a way that, given access only to most common tools, is impossible to remove. The connection between air transport system (from the piston chamber) to the elbow connector is a tight sliding fit, where the end of the air transport metal tube goes into the elbow connector until it hits a rib on the end of the metal tube. Then, a hexagonal bolt is tightly screwed onto the threaded exterior of the elbow connector, securing the physical connection between the metal pipe and the elbow connector. When the air compressor is active, it also reflects a mass and energy connection. That is, with pressurized air coming from the piston chamber, the air, embodying mass with kinetic energy, passes through the elbow connector and enters the lower pressure environment of the air storage tank. The reason for this connection should be evident, as the air storage tank (which is required to build up pressure in the air compressor) needs to be provided pressurized air from the piston chamber, and part of the air transport system performs this function. This connection is implemented by a connector that is made of a strong, un-malleable metal that is most likely an alloy, as this would noticeably enhance its strength properties (as a mixture of metals often has higher allowable limits for stress and strain) and reduce its final cost relative to any pure metal (aside from being weaker than mixtures, larger amounts of pure metal are more difficult to obtain in order to create custom shaped pieces like this elbow connector—driving up cost). The economic concern here is evident, as are environmental concerns, as the requirement for large amounts of pure metal are more deleterious to the environment than mixtures that can be formed from recycled products. Possible societal concerns exist, as a product that requires heavy mining may be unpopular with the public, as mining is a dangerous activity that takes the lives of many each year.

Fan and Crankshaft Subsystem Connection

Finally, the connection between the cooling fan and the crankshaft is one of simplicity and convenience. The fan and crankshaft share a rigid physical connection that allows the fan to rotate at the same speed as the crankshaft. With this rotation, the fan moves the air around it. To answer the question why, this method seems to be the easiest engineering solution to a cooling problem. The connection is by a screw placed through the center ring of the fan causing pressure against the rotating shaft to which it is connected. In respect to an environmental and economic standpoint, the fan is made of a common alloy and is cast instead of being machined, thereby being cheaper to manufacture. Furthermore, performance needs of the compressor are such that the energy expended to operate the fan does not hinder the performance of the compressor enough to warrant a separate cooling mechanism.

Appendages and Energy Storage Subsystem Connection

The only remaining connection to mention is that which is constituted by the physical connection between the appendages and air storage subsystems. The handlebar is connected by being slid into two cylindrical rings that are soldered to the upper sides of the tank, and then is secured there by four small screws, two on either side of the U-shaped handlebar. The next individual connection is that of the wheels to the tank, which is accomplished via two nuts and bolts, one of each for each wheel. Each bolt passes through the center of a wheel and one of two metal legs that are soldered to either side of the rear end of the storage tank. The third and final connection is the one which encompasses the two rubber supports’ connection to the air storage tank. A simple screw through the center of each support is used to secure them. All three of these connections are part of the “wheelbarrow” model by which the air compressor is designed. The handlebar connection is designed to accommodate the moment that would be produced when the product is lifted up onto its back wheels, and the applied forces that would be present during the compressor’s transportation. The bolt and nut system that is used to secure the wheels to the tank is a sufficient way to support the load of the compressor, while still allowing the wheels to rotate so that the product can be moved in a convenient fashion. Finally, the screw by which the rubber supports are attached is necessary to keep them in place when lifting the compressor up onto its rear wheels. In analyzing these connections, it is apparent that the global, societal, economic, and environmental concerns are fairly simple, like the connections themselves. The materials used to make these connections possible are abundant and inexpensive. Therefore, they have a low impact on the consumer and the environment. The performance demands of the appendages system are fundamental, and a system of little sophistication is required. As long as the connections are able to support the force that will be applied by the user and the weight of the compressor itself during basic movement of the product, they will be sufficient.

Subsystem Arrangement Analysis

In this final section, the arrangement and reasoning for arrangement of the subsystems is analyzed. The analysis begins with the air intake subsystem, of which the air filter should be clearly visible to the user as it is placed on an upper corner of the black hard plastic protective covering. After removing the hard plastic cover, it is evident that the external air filter is directly connected to the piston housing (as discussed above). The reasoning for such placement of subsystems is obvious. Defining the air compressor in itself as the higher system, for air to be taken into the system, negative internal pressure must be created within the system (air compressor). The piston provides such negative pressure during its descent down the cylinder, which is why the piston chamber subsystem must be directly connected to the air intake system.

Providing for the vertical displacement of the piston is the crankshaft system, which explains why these two subsystems must be directly adjacent to each other. There is no other evident method to transfer kinetic energy to the piston within our given higher system (the air compressor). Of course, in order for the crankshaft subsystem to acquire rotational kinetic energy, one end of it must be directly surrounded by the electric motor subsystem (refer to above discussion as to why). The placement of these three subsystems (piston chamber, crankshaft, and electric motor) form a line, which is essential to their sub-functions of transferring energy, which is useful to the higher function of ultimately providing compressed air. At the motor end of this line (the end opposite the piston chamber), the fan subsystem is conveniently placed on tip of the crankshaft. The fan subsystem must rotate to perform its function of cooling down the entire system during operation (particularly the motor). Since the crankshaft is always rotating during the operation of the electric motor, this allows for the fan to be always active in step with the motor. Although powering this fan does reduce the potential for work by the piston, it does not make sense to provide the fan with its own independent power source (since the fan does not take away that much energy from the potential of the piston to perform work).

The next two subsystem placements to be explored are the regulator and the air storage tank. First to be analyzed is the placement of regulator. One important consideration to be made here is that the regulator, with its electronic parts, should be protected from the varying magnetic fields created by the electric motor. Protection from the electric motor can be provided by either shielding the regulator from the potential of electromagnetic interference, or by simply placing it far enough away from the motor that this is not an issue. As the area surrounding the motor in this air compressor is fairly occupied, it makes sense to simply place the regulator at the opposite end of the storage tank (refer to pictures).

Given the specifications of this compressor’s product envelope (i.e. the 8 gallon air storage capacity), the air storage tank, relative to the rest of the structure, requires a special layout. When choosing the shape and dimensions of the air storage tank, one must consider a few factors. For instance, as the storage tank fills with air, it will become increasingly heavy with time. Also, given the weight increase of the entire structure, one must take into account the relative ease by which the air compressor can be transported. For these reasons, the air storage tank forms the foundation and the base of the structure. This way, as the tank gets heavier, the weight does not bear upon other components (since it is the base of the structure). Also, this configuration allows for the structure to be transported like a wheelbarrow, where one can essentially pull on the handlebar, allowing the structure to roll.

Finally, the placement of the power input and the air transport subsystems is analyzed. These two subsystems are somewhat similar in the sense that, physically speaking, they have flexible components (wiring for the first, tubing for the latter). Unlike how the piston chamber, crankshaft, and electric motor must be placed in a line, there is no specific requirement for the physical arrangement of these components. All that is required is that these subsystems be connected in a way that allows them to perform their required serial sub-functions (for instance, the power input system must connect to the electric motor in order for it operate, and it must be done in a fashion that allows for this serial process of power input to electric motor). For the most part, wiring for the power input system and metal hosing for the air transport system is done in physically arranged in a way that is space efficient. That is, the wiring and the metal hosing straddle existing structures so that space taken, along with material required for these subsystem (e.g. copper wiring, etc) is minimized. The economic concerns here are evident (refer to discussion above on how connections are implemented for further detail).

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