GATE 2: Product Dissection

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Contents

Product Dissection

Ease of Disassembly

\'\'\'Difficulty Scale\'\'\'

\'\'\'Table 1\'\'\' below shows the difficulty level of each step of the dissection.

\'\'\'Level of Difficulty\'\'\' \'\'\'Description\'\'\'
1 Parts were quickly removed by hand
2 Parts were easily removed by one person with a simple tool, minimal effort required
3 Parts required some effort and skill to remove; repetitive jobs
4 The parts required personal tools not supplied in the lab, two people to remove and some strenuous work
5 Time consuming and very difficult to remove, maybe causing some challenges

The dissection of the engine involved many steps to take apart different systems. There was much time and effort spent to disassemble the Honda Engine.


\'\'\'Dissection Plan\'\'\' The dissection of the engine was completed by two groups, Group 13 and Group 23. A joint effort was done taking apart subsystems and then were broken up between the two groups. The following is how Group 23 proceeded to take apart the Honda engine.

Dissection Process

\'\'\'1.) Air Box\'\'\'

\'\'Tools:\'\'

Philips head screwdriver used to loosen screws.

\'\'Difficulty:\'\' 2

\'\'Procedure:\'\'

- 5x16 screws and their washers were removed that connected the top and bottom halves of the air box. The top halve was then removed.

- This opened up the box so the filter can be removed.

- The bottom half of the air box covering was removed by loosening the clamps on the carburetor using a Philips head screwdriver and then it was pulled of.

\'\'Intention of Disassembly\'\' This part was clearly intended to be disassembled when necessary. It is the most accessible, being on top of the engine, and fairly simple to disassemble. With only a few screws to remove any average man or woman can take apart the Air Box and change the air filter.

IMG 0015.jpg

\'\'\'Figure 1.\'\'\' Picture of the Air Box on top of the Honda Engine

\'\'\'2.) Carburetors:\'\'\'

\'\'Tools:\'\'

Philips head and flat head screwdrivers used to loosen screws and push on an arm. 10 mm and 8 mm socket wrenches to loosen corresponding nuts and/or bolts.

\'\'Difficulty:\'\' 3

\'\'Procedure:\'\' A group of two Carburetors was taken home by one group member so he can disassemble it there. The other group of carburetors was left in the Lab.

-After the clamps were removed, in the previous step, the Carburetors were simply pulled off by hand.

\'\'Further Dissection:\'\'

- The four Carburetors were separated into groups of two using a 10 mm and 8 mm socket wrench to loosen several nuts.

- Several screws are loosened using a Philips head screwdriver to remove a chamber cover and a flat head screwdriver.

- The Jet was released using a Philips head screwdriver.

- Using the point on a screwdriver the Float was removed by pushing on the Float Arm.

\'\'Challenge(s)\'\'

One of the Carburetors had some stripped bolts which are difficult to take out without a special tools. This was not an extreme problem considering all of the Carburetors are the same and therefore only one of them was needed to understand how to dissect.

\'\'Intention of Disassembly\'\' This part is not intended to be dissected by just any average man. It should be handled only by professionally trained mechanics because of the importance and sophistication of the processes that occur during use.

IMG 0017.jpg

\'\'\'Figure 2.\'\'\' Picture of the Carburetors fully assembled but detached from the Honda Engine

\'\'\'3.) Valve Cover\'\'\'

\'\'Tools:\'\'

10 mm socket wrench to loosen corresponding nuts and/or bolts.

\'\'Difficulty:\'\' 2

\'\'Procedure:\'\'

- Loosen bolts and washers using a 10 mm washer.

- The cover was then lifted off by hand.

\'\'Intention of Disassembly\'\' The dissection of this product is not needed unless to get to other systems within the engine, therefore the intention of disassembly of this product depends on where the laborer is heading from this point.

IMG 0035.jpg

\'\'\'Figure 3.\'\'\' Progress of detaching the Valve Cover

\'\'\'4.) Camshaft\'\'\'

\'\'Tools:\'\'

10 mm socket wrench to loosen corresponding nuts and/or bolts. Flat head screwdriver to produce leverage.

\'\'Difficulty:\'\' 3

\'\'Procedure:\'\' Camshaft covers hold camshafts in place along with a timing chain on the gear ends of the camshafts.

-2 nearly identical covers had 10 mm bolts that were loosened by the corresponding socket wrench.

- The covers were firmly attached to the head and required two members to simultaneously pull on the cover and separate the covers with a flat head screwdriver.

- The Camshafts were removed by first loosening and removing the timing belt, shown in the next step, and then just lifting them off with little effort completely removed them.

\'\'Intention of Disassembly\'\' The dissection of this subsystem should only be done by professionals. This is another important and sophisticated system with the processes of the engines to run perfectly.

IMG 0023.jpg

\'\'\'Figure 4.\'\'\' Picture of the Camshaft with one covered, one open, and the timing belt still attached.


\'\'\'5.) Timing Chain\'\'\'

\'\'Tools:\'\'

- 8 mm, 10 mm, and 14 mm socket wrenches to loosen corresponding nuts and/or bolts.

\'\'Difficulty:\'\' 4

\'\'Procedure:\'\'

- The cover on the side of the crankcase was detached using a 10 mm socket wrench to loosen the bolts.

- Loosened and removed the tensioner by loosening the bolts that connected it to the crankcase using an 8 mm socket wrench.

- Plastic guides that guide the Timing Chain were removed by using both 14 mm and 10 mm socket wrenches.

- The gear was then removed and the chain became loose enough to be pulled through the top.

\'\'Intention of Disassembly\'\' The dissection of this system is not recommended unless dire. Timing is everything with the overall process of the engine and should not be worked on.


IMG 0028.jpg

\'\'\'Figure 5.\'\'\' Timing Chain being removed from the engine

\'\'\'6.) Engine Head\'\'\'

\'\'Tools:\'\'

- 8 mm, 10 mm, and 16 mm socket wrenches to loosen bolts and pressure gauge - 16 mm socket wrench that was attached to \'Spinner Handle\' drive tool instead of the traditional ratchet handle. - 8 mm and 13 mm wrenches to remove bolts. - Rubber mallet used for striking objects attached by no nuts, bolts, or screws but instead by grooves at the connection points.

\'\'Difficulty:\'\' 5

\'\'Procedure:\'\'

- 8 mm bolts were loosened between Camshaft cavities and 10 mm bolts on one end of the Head towards where the Timing Chain was located.

- A rubber mallet was used to strike the Engine Head while the rest of the engine was supported by another member until it was loosened. The Head could then be lifted of the rest of the engine and the gasket that was present would just slip right off without any use of tools.

-\'\'Further Dissection\'\'

- Four Spark Plugs were removed by:

-(1) initially loosening them with a 16 mm socket wrench with the traditional ratchet handle

-(2) then loosening them even more with the same socket wrench bit but instead using the Spinner Handle drive tool.

- Three bolts were removed using an 8 mm wrench to remove an external pipe (shown in figure 7).

- The Pressure gauge was removed using a 13 mm wrench.

\'\'Challenge(s):\'\'

(1) We initially loosened the Spark Plugs with the 16 mm socket wrench attached to the traditional ratchet handle. After one quarter turn, the ratchet appeared to be not loosening the Spark Plugs anymore. We had no idea why and did not know what to do until we just tried other tools. We then attached the 16 mm socket to the Spinner Handle and it loosened the Plugs until you just tipped over the head and the plugs just fell right out.

(2) When we removed the external pipe on the engine head we observed that it was broken. Surrounding the screws there is large crevice that bends the part completely backwards but is not large enough to break completely. There is no other fix to this than getting a brand new part for this section of the engine.

\'\'Intention of Disassembly\'\' Will the difficulty of assembly and importance of certain parts within the head (i.e. the spark plugs) this system should not be attempted to take apart unless there is a verifiable fact that there is a problem with it.

IMG 0032.jpg

\'\'\'Figure 6.\'\'\' The Engine Head after disassembled.




EngineOuterPipe.jpg \'\'\'Figure 7.\'\'\' The external pipe (not shown: damage).

\'\'\'7.) Stater System\'\'\'

\'\'Tools:\'\'

- 8 mm and 10 mm socket wrenches to loosen bolts. - 7 mm and 10 mm wrenches used to loosen bolts and gauges.

\'\'Difficulty:\'\' 2

\'\'Procedure:\'\'

- Bolts that connected the Starter to the crankcase were loosened using 10 mm and 8 mm socket wrenches.

- The Starter was then pulled out of the crankcase.

\'\'Further Dissection:\'\'

- Ignition bolts that held the casing together were removed using a 7 mm wrench and the end caps were then pulled off.

-The gauge on top of the ignition was then removed with a 10 mm wrench.

- The inside magnetic component was then removed from the outer casing, concluding the dissection of the ignition system.

\'\'Challenges:\'\'

- The gauge was attached through the casing to a ring and in order to remove the gauge, you had to push it through the casing. This was difficult because the inside component was getting in way of the ring and therefore the gauge could not be removed. To overcome this, the ring and gauge had to be maneuvered so they could both come out of the ignition system.

\'\'Intention of Disassembly\'\' This product should not be disassembled, if there is a problem, it should be replaced completely with kits that they sell.

Ignition.jpg

\'\'\'Figure 8.\'\'\' Ignition System completely disassembled.

\'\'\'8.) Piston Removal\'\'\'

\'\'Tools:\'\'

-10 mm socket wrench to remove nuts -Rubber Mallet to loosen Pistons -Needle nose pliers to reach down and grab piston ring

\'\'Difficulty:\'\' 5

\'\'Procedure:\'\'

- 10 mm socket wrench loosened nuts that held them to the connecting rods.

- The Pistons were then removed using a rubber mallet to forcibly remove them.

\'\'Challenge\'\'

- One of the piston rings was getting caught during the removal, probably due to previous dissections and rebuilding from other groups before. This required the use of needle nose pliers to remove the ring.

\'\'Intention of Disassembly\'\' The pistons should not be removed unless they need to be fixed. Usually a problem with the piston is caused by an overall problem with the engine.

IMG 0054.jpg

\'\'\'Figure 9.\'\'\' Shown is the bottom of one piston.

Subsystems that are connected

\'

This is a basic overview of the subsystems connected in the top, middle and lower part of the engine:

(1) Top of the engine: Intake valve, (rocker arm & spring), valve cover, intake port, head, camshaft, exhaust valve (rocker arm & spring), spark plug and exhaust port

(2)Middle of the engine: Coolant, piston, and connecting rod

(3)Bottom of the engine: Engine block, rod bearing, crankshaft, oil pan, and oil sump

\'\'\'Physical Connections of the Subsystems: Table 2\'\'\'

GATE2table2.pdf


Table 2 shows how the subsystems are connected. As seen in Table 2, most parts of the engine are connected by bolts. However, the important thing is what the physical relationship is between subsystems when the engine generates power. The intake valve and exhaust valve are connected to the camshaft. When the camshaft rotates one time, it pushes the intake valve. Thus, air comes to intake port and combines with fuel to move pistons. The pistons move up down by rotation of crankshaft. The pistons are connected to the crankshaft by connection rods. When the crankshaft rotates, it gets oil from the oil sump. The crankshaft is connected to camshaft by the timing chain. The chain provides causes the camshaft and crankshaft to work together in sync. When the air and fuel combust, the camshaft pushes exhaust valve and the combusted air goes to out of the system.

The flywheel is connected to crankshaft by a flywheel bolt. When the crankshaft moves, the flywheel turns in a circular motion. Notches in the flywheel attach it to other vehicle components that spin the wheels.

\'\'\'Table 3: Flowchart of the subsystem (Four stroke Engine)\'\'\'

GATE2table3.pdf


\'\'\'Signals\'\'\'

• Spark from sparkplug ignites fuel/air mixture causing combustion • Electrical impulse from alternator powers time chain • Stepping on gas petal causes throttle to open/close in direct correlation • Time chain allows camshaft to rotate precisely in order that intake and exhaust valves open and close properly


\'\'\'Energy\'\'\'

The pistons are connected to crankshaft by connection rods. Thermal energy produces pressure in the combustion chamber, and the pressure boosts mechanical energy. The mechanical energy pushes the pistons down. When the crankshaft rotates, it gets oil from the oil sump. Crankshaft is connected to camshaft by timing chain. The chain provides camshaft and crankshaft work together in sync. After the combustion of the air-fuel mixture, the camshaft pushes exhaust valve and release the mixture out of the system. (2)(3) Flywheel is connected to crankshaft by flywheel bolt. When the crankshaft moves, flywheel turns in a circular motion. Notches in the flywheel attach it to other vehicle components that spin the wheels. (3)

Why are they Connected?

All of the subsystems that create the engine are connected because their connected continuity allows the engine to flow as one working mega system. If any part of the subsystem were to be disconnected from the mega system then we would have a failure somewhere within the engine that would cause the product to not function correctly.

\'\'\'Subsystem Design Factors\'\'\'

With any product ever made there are four major factors that must be considered before production. Two very similar factors are the global and environmental concerns. In the past decade the rising concern of global warming and the environmental impact has rapidly become important during the process of designing and making new products. However, during the early nineties when the motor was designed and mass produced the concerns of global and environmental impact were not major. There was more of a push for the performance that the engine could output, rather than the amount of harmful emissions it released into the atmosphere. People would rather the motor have more performance output than to have it get an insane mpg rating. Another factor in design is the societal impact. In the early nineties society was taking a turn for the sports bike opposed to the typical touring bike. They were looking for a bike that was fast, light and sporty looking. This is why Honda made the CBR 600, to supply the demand of society. They made the engine along with its subsystems to output peak performance for the consumers. The motor was made to “red-line” at higher RPMS so that more performance and torque could be given to the consumer. In order for this to work the subsystems such as the crankcase, transmission and even the pistons were made to withstand more than ever before. One of the best selling aspects of any product is the cost and quality of the item. Economically the world was doing fairly well and cost was less of a factor as longs as if the motor lived up to the performance hype. Of course cost was took into account during the design and selling process so that consumers would purchase the motorcycle, however, people were willing to pay for the performance of the CBR 600 sports bike.

Our engine is an internal combustion engine. This type of engine is commonly used in motorcycles, airplanes, automobiles and is more efficient than external combustion engines (i.e. steam engines from old fashioned trains and steamboats) in that they need less fuel per mile. Also, internal combustion engines are much smaller in total mass and volume than external combustion engines. This adds to the internal combustion’s efficiency in that it uses less space and takes less building materials per volume to manufacture. Said reasons imply that the internal combustion engine is cheaper to manufacture, therefore can be purchased at a cheaper price. Also, since the internal combustion engines need less fuel per mile, this implies that fewer emissions are exhausted into the atmosphere, making the internal combustion engine more eco friendly.


Subsystem Arrangement

All of the subsystems work together in an orderly fashion to ensure the best possible overall performance of the engine. There is a specific arrangement in the engine that allows the motor to work properly. In almost every engine gravity intake because it is used in the process of the carburetors combining the air and fuel mixture into head. This is where there are several thousands of explosions that occur allowing energy to make the engine run. The engine is a process of converting energy through several different subsystems like mentioned above. If any of these subsystems arrangements is changed then the ability for the engine to run would be hindered. This is the reason the every subsystem has a specific placement.

References

(1) Spark plugs (NGK spark plugs). Retrieved October 26,2010 from http://www.ngkspark.com.au/sparkplug.php#

(2) Crankshaft.(n.d). Retrieved October 25, 2010, from http://www.wisegeek.com/what-is-a-crankshaft.htm

(3) Flywheel. (n.d.). In Wikipedia, The Free Encyclopedia. Retrieved October 25, 2010, from http://en.wikipedia.org/wiki/Cylinder_(engine)