Engine disassembly requires a systematic approach. Aside from having all the tools necessary at your disposal, you must also have a basic understanding of how the engine works, and a plan to disassemble and organize all of the components. Upon examination of the engine, we have so far determined that we will need Philips and flathead screwdrivers, as well as a basic socket set. We are unsure of the bolt sizes, so we will need a full set to get started. We also need open ended wrenches to get at bolts in tight spaces, as well as pliers to disconnect clamps and lines.
External Parts Disassembly
First, we must remove all of the external parts from the engine. This consists of the gas tank, the starter pulley assembly, the carburetor, the spark plug and wire, and the plastic cover over the engine. These parts are mounted to the engine with screws and bolts that look to be easily removable with hand tools. First, we will remove the plastic cover, then the gas tank, the carburetor, the starter assembly, and the spark plug assembly. Once the gas tank is removed we can disconnect any fuel lines that may be present. Once all of the external parts are removed from the engine we can begin removing the internals of the engine.
Internal Parts Disassembly
We have not yet seen the internals of our engine, but we have an understanding of how it works. This allows us to create a basic plan to disassemble the internals of the engine, which can be modified as the disassembly happens. We must disconnect the crankshaft from the connecting rod, and remove it. Then the piston and connecting rod can be removed as one. Once they are out of the engine, the connecting rod and piston can be disconnected. This will require the removal of bolts. Once these major components are removed we can determine if any other disassembly is necessary.
All but one of our group members don’t have any hands-on experience with engine disassembly. However, we all have a basic understanding of how the engine works, and how to use hand tools. This allows us to create a plan to systematically disassemble the engine, and learn as we do it. We estimated that it will take us 1-2 hours to properly disassemble the motor, and organize the components; a break down of the time we think it will take can be seen in the Gantt Chart in Figure 1 below. This is assuming we do not run into any snags in the form of frozen bolts, or hidden components. All of the group members are confident in our ability to disassemble the engine in a reasonable amount of time, but we do expect that we may develop some skills alone the way. Most of us feel we have some lack of skills when it comes to working as a group successfully, we all believe that this is one of our short comings and hope that we can develop those skills as we learn to work together with each other.
Group 13 2011 Management Proposal
We needed to set aside a normal time that we can all meet regularly throughout the semester to organize our thoughts and determine what each of us needs to do each week in order to complete the project. We have decided that we should meet 2 to 3 times a week and plan to have those meetings on Monday, Wednesday, and Friday after MAE 277 when we are all free. We will all attempt to meet together, but if this is not possible two or three of us could still meet and confirm our plan with the rest of the group via email or text message after the meeting. We each will be assigned roles to attempt to organize the work process. Those roles are as follows:
Technical Adviser - Dylan McCann
The technical adviser has previous knowledge of the product, in this case a lawn mower engine. He will use his knowledge to guide the group toward achieving better understanding of what they are dealing with. This basic knowledge will make it easier for the group to dissemble the product to learn the name of each part and what it's function is. The technical adviser will be in charge of writing technical assessments and models which will make the project more professional. He will coordinate with the editor to make sure final drafts are correct in respects to the technical aspects and will also ensure all mathematical calculations are without mistakes.
Project Manager - Tyler Lynn
The project manager's main goal is to keep the project on track to meet deadlines and to see to it that everyone knows what they should be doing. He will direct the group as to what the next step is for completing a certain task. He will decide what the most important aspect of the project is at any moment and prioritize it among the group. As project manager is in a sense in charge of the group it is up to him to make sure everything runs smoothly both within project and among fellow group members. To settle disputes about the project, the project manager will get the opinion of all members and together come up with a reasonable solution. It is also his job to coordinate with the communication liaison to figure out when certain deadlines should me made.
Communication Liaison - Timothy Li
It is the job of the communication liaison to keep the group informed of meeting times, project deadlines, and any other news the group may need to know. He is responsible for setting up meeting times and places that works best for the entire group. A key job for the communication liaison is to make sure everyone in the group knows when any part of the project is due. He will set deadlines to ensure that each project gate is finished by it's due date. The communication Liaison will also function as the main line of communication between the group and our professors for any questions or issues that we may have.
Editor - Garrett Lust
The editor's main responsibility is to look over all work done and make sure there are no errors or mistakes. The editor is to ensure that everything is presented in a finished, professional manner before the project gates are to be turned in. He will look for problems to fix and help solve those problems by providing constructive criticism when necessary. He will consult the entire group when fixing any errors found to produce the best possible result. The editor will also be responsible for putting information onto the group's wiki page and to keep the wiki presentable.
Group 13 2011 Product Archaeology
Our product is a Tecumseh TNT100 series engine that was used in a Toro lawn mower engine in 1984. Toro is an American based lawnmower and tractor manufacture that has been around since the early 1900's. Our engines fuel economy, at this time, was not a huge design factor as it would be today because the cost of gas was much cheaper in the US in the 1980 and there were less cry from the global community to be environmentally friendly. The development of the engine had one main goal, which was to produce enough power to mow a lawn with low production costs. This type of engine would have been designed typically to be sold in middle class to low suburban areas in first world nations, for the sole purpose of making the consumers property look more presentable as it was a mid-cost lawn mower at the time.
The intended use of this engine was to make mowing the lawn faster and easier then it would using a mechanical based cutting device, by having the engine do most of the mechanical work for you. It would have been marketed for personal use or possibly for a small business. The motors main function would have been to turn the blades and propel the self-propelled push mower that it was made for.
The engine uses many forms of energy including chemical energy, electrical energy, rotational energy, and mechanical translational energy. The engine was ignited when human energy is used to pull a cord to start the engine. Human energy pulls the cord, which is connected to a rotational crankshaft. This creates rotational energy is partially converted to electrical energy via a small electro magnetic generator and the remaining energy is used to help move the piston inside the piston-cylinder up and down. The electrical energy is used to generate a spark in the piston-cylinder. This spark ignites a chemical reaction that burns the gas in the cylinder using chemical energy and pressure that helps to continue to drive the piston up and down. The piston’s motion turns a crankshaft converting the piston’s translational energy to rotational energy on the crankshaft. This shaft drives the blades rotation and may be transferred to the wheels via some type of gear assembly. This process can be seen graphically in figure 2 below.
Less then 50 unique components, not counting individual bolts and screws, are used in this type of one cylinder engine. There is a piston connected to a rod and crankshaft, flywheel, gear train (could have several gears), oil pump and valves and valve springs which account for most of the internal moving parts. Since the engine does not achieve high revolutions per minute, it does not need to be overly complex and contain things like a separate camshaft or have high tolerances like a much larger engine would have.
The product is clearly made up of plastic, metal, and rubber. Most of the engine is made of what appears to be aluminum because it seem light and is mostly non-magnetic, but some components are made of iron or steel and are heavy and magnetic. The engine has many screws and bolts that hold the outer parts together. There is electrical wiring, most likely copper, that runs from under the flywheel to the spark plug. A plastic shell covers most of the visible parts. Parts that are not visible may be steel or aluminum or possibly rubber seals and plastic components.
The consumer pulls a cord that rotates a gear to start the engine. There is a cap for adding fuel and another for adding oil. An integrated dipstick in the oil cap is used to check the oil level and condition. The user can also interface with the carburetor by priming it and adjusting the choke. The interfaces are pretty standard and a user could figure out how to use this engine based on common knowledge of other engine's interfaces that most people have used before; a person with little to no knowledge of how and engine functions can still learn to use that product very quickly. Regular maintenance is required; however it is frequently needed. The oil needs to be changed and the spark plug eventually would be worn out both of which requires some knowledge of how these components should look and function. The air filter and the carburetor should be changed or cleaned regularly as well. While these maintenance steps may not be as intuitive as the engines usage, many companies exist around the country and globe that have the knowledge and skill to service and maintain this engine for reasonable cost for the user.
All lawn mowers use the rotation of blades to cut grass but what energy source you use is up to the designer. Alternatives for the lawn mower engine would be a manual or an electrical lawn mower. The manual lawn mower requires only human energy with a cost range of $100-$150, but it requires a person to push it, which rotates the blades through a gear train driven by the wheels contact with the ground. The electrical lawn mower uses an electrical source as its power. It could be powered by a battery or a cord connected to an outlet. For an electrical lawn mower, an electric motor would replace the internal combustion engine in our design. They can have a cost range of $100-$250. The mechanical lawn mower uses a fuel source to power the engine. Typically gasoline would be used as a combustion source. These lawn mowers can have a cost range of $200-$500. Each lawn mower has its own advantages and disadvantages. The manual lawn mower is the cheapest one. It requires little to no maintenance, and requires no fuel or electricity. However, it requires the most human energy, so one would be required to do the most work. An electrical lawn mower produces no pollution and requires little maintenance, but it may require a cord for an electrical source and that my limit the distance the lawn mower can go or if they are battery operated, they will have a limited range and less power. The gasoline driven mower is the most costly, but the most powerful, most hassle free and has the farthest range with least amount of human work input, which is why it is the most common type of lawn mower used.