Engine Strip and Build - Lab Report Example

Engine Strip & Build Assignment MP1532 Manufacturing Engineering 5th may PART Honda GX160 Engine is a 5.5 h.p engine with oil alert and electronic ignition and has one piston. It can be used in many areas which includes pumps, cement trowels, construction equipment air compressors and generators. Below are the pictures of this type of engine. The following is the procedure to be followed when striping, inspection, measurement and re-build of a functioning of Honda engine Before the start of the disassembly procedure, both fuel and engine oil should be emptied because fuels is highly flammable hence dangerous while the engine oil can stain anything it comes in contact with Removal of fuel Tanks 2 pieces of M6 nuts and 1 piece of M6 bolt that are in between exhaust box and airfilter were removed. The tank eased up and rubber was also removed. Finally bolts and nuts was replaced on the tank fittings. The tools that were used are 10mm spanner, extension and 10mm socket Removal of throttle handle and Carburettor Air cleaner and housing was removed by loosening the wing nuts. Then throttle handle was removed by loosening 2 *M6 nuts holding the lever and, 2 bolts on the linkages was also removed. The spring that withdraws lever was also removed. Breather was then disconnected. Carburettor was removed from the studs, rods and small spring was also removed .The position of the governor was also marked. Gaskets and Plastic spacer was removed at the same time noting their orientation and position. Bolts and nuts were replaced. The tools that was used for this procedure were; 10mm socket, ratchet, extension and 10mm spanner Removal of heat shield and exhaust silencer 3 pieces of M6 bolts holding the heat shield to the silencer were removed and the cover lifted. 2 pieces of M8 nuts was removed from exhaust pipe so in order to loosen and release it from the cylinder head. Tools that were used was 10mm spanner, extension and ratchet and 10mm and 12mm socket Removal of Spark Plug and rocker cover 4pieces of M6 bolts was and the cover was the lifted careful to ensure that the gasket is not damaged. The plug head was pulled off and the spark plug using spark plug socket and unscrewed using hand. The tools that was used in this procedure were sparkplug socket, (21mm), 10mm socket and 10 mm Ratchet extension Removal of cylinder Head 4 pieces of M8 bolts are removed whereby 2 are located at rocker box, the procedure undoing the bolts was done in diagonal manner. The cylinder head and gasket was removed carefully, watching the push roads and dowels. Finally the bucket shim on the exhaust valve was removed and parts set aside carefully. The following tools was used Extension socket and Tommy bar MEASUREMENTS Cylinder bore =68mm or6.8cm Piston stroke= 45mm or 4.5cm Deck height volume= 0.03 head gasket volume= 0.1= 3.6317 combustion chamber volume= 18.1 ASSEMBLYING Assembly is the reverse of dis-assembly. This means that the last part to be removed from the engine assembly was the first one to be assembled. Cylinder head was replaced and bolts tightened. Push rod, exhaust valve rotator and pushrod under the rockets were replaced. Piston was fitted Rocker box were and spark plug was fitted Governor linkage was reassembled Others was also re assembled were followed were carburetor, fuel pipes, air filter, exhaust and heat shield. Fuel tank was filled with fuel and the engine was now ready for use Calculation Compression ration = (swept volume Deck + Deck height Volume +Head gasket Volume + combustion chamber volume)/(Deck height volume + Head gasket volume +combustion chamber volume) Deck height volume= 6.8^2 * 0.7854 * 0.03= 1.0895 head gasket volume= 6.8^2 * 0.7854 * 0.1= 3.6317 swept volume= 6.8^2 * 4.5 * 0.7854= 163.4260 combustion chamber volume= 18.1 Compression Ratio= (163.4260 +1.0895+3.6317+18.1)/( 1.0895+3.6317+18.1) 186.2472/22.8212 =8.1611 Part 2 (A) - Detailed Component Investigation Part 1 – ALTERNATOR BRACKET The material that is used to make alternator bracket is an alloy of cast iron. Cast iron is preferred because of its strength, cost and the ease of casting it. Alternator bracket should be made of very strong materials because it’s carrying alternator that is connected to the engine pulley by a highly tension v-belts, the bracket is also subjected to vibration because when the belt is in use, its elastic properties cause the bracket to vibrate. Two processes are used to produce the part, namely; casting and machining. Metal Casting is a process whereby liquid material is poured into a mold, of the desired shape and left to solidify. Solidified part is knocked out of the mold or ejected to complete the process. This method is used to make complex shapes that are Uneconomical or difficult to make by using other methods (Degarmo, et al. 2003). The first process is to design a mould that is in the shape of the alternator bracket and should be made from ceramics because they are not affected by high temperate of hot metal. The cast iron alloy is heated in vessel or furnace until it is melted and form a liquid, and then poured into the mould and left to solidified and removed from the mould. The next process is machining some parts that will be in contact with other parts of the machine, like the surface that will be in contact with the engine block and parts of the holes which are in contacted with the head of the bolts. The best machining process is milling and is done while the part is secured on the bench with the vice. Another alternative method for producing this part is using the process called joining, whereby different parts are cut from metal sheet and welded to form this part. Part 5 – CRANKSHAFT The crankshaft is the part of the engine that is rotated by the pistons, and it runs along the length of the engine. The main bearings are used to support the crankshaft. The main materials that are used to manufacture crankshaft is steel alloys which is commonly used in high strength crankshafts and is selected for what each designer perceives as the most desirable combination of properties. The following is the normal properties of crankshaft materials;Figure 6 shows the nominal chemistries of the crankshaft alloys The main parts of the Crankshaft are; crank nose, mount for crankshaft, main bearing journal, oil way, counterweight, crankpin journals, The following are the calculation on how to determine the amplitude of the crankpin journals. The amplitude of the crankpin is achieved from the stroke distance from bottom (stroke) 45mm; this will be the distance between main journals and crankpin journal. Also, since the crankshaft will be used for 4 pistons engine the angle between crankpin journal is obtained by; =360O/4 =90o The crank shaft undergoes three manufacturing process, namely Forging, drilling and machining The die for forging is designed taking into consideration the shape of the crankshaft, which includes pockets for the counterweights, main journal, and crankpin journal, the hammer is also prepared to take the shape of the crankshaft. The advantage of forged crankshaft is in its strength that is far much better as compared to other methods. A steel ingot is heated in a furnace to about 2,200 degrees F at this point the steel is easily formable, but it is not in liquid form, this is very easy to move around and shaped (Castro, Antonio, & Sousa, 2004).A Very hot ingot is placed in the die that is used for forging and squeezed into the nearly desired shape of the crank profile. This act of squeezing is achieved by either pressing or hammering process. This process is used to increase the strength by compacting the molecules, strengthen and the grain structure, it is also to compress the alloy mix to fill precisely the die. During the compacting process, Materials that are excess is forced out of the die at its joining lines that are later sheared off in a trimming die. After trimming, the forged shape is quenched and tempered followed by Heat-treatment whereby the crank is deep into a glycol solution. The next process after forging is drilling whereby the flywheel mounting holes, main journal oil holes and crankpin oil hole are made using a drill. Drilling is the process of cutting holes using a drill bit to enlarge or cut a hole with a cross-section that is circular. The drill bit pressed on the work piece, and as it rotates, it cuts away some unwanted materials. The work piece is secured in bench using vice; the holes on the flywheel flange are drilled perpendicular to the surface and equidistance to one another. The holes are then threaded or tapped in order to hold the bolt. The oil hole connecting both main journal and crank pin journal are drilled diagonally connecting the two centers and coming to the surface; this is to provide oil for lubricating the bearing. Diagonal hole for oil. The last process after drilling is machining in order to achieve very précised and smooth surfaces. The tools that are usually used are lathe machines or CNC. Two methods can be used Turning or milling, whereby in Turning the cutting tool is stationary and does not rotate while the part being machine is rotated. In milling, the cutting bit rotates while the part being machines can be rotated or remain stationary. Milling is the most preferred method, and during this process, a very thin layer of materials is removed from the crankshaft. Another alternative method for making Crankshaft is fully machining it using CNC machine, this method is slower, incurs a lot of wastage though it’s very easy to automate the process. The last method that can be used to manufacture the crankshaft is producing in small parts then assembling them as shown below Part 7 – FUEL INJECTOR RAIL Fuel injector rail is also known as common rail and is used to deliver fuel to individual fuel injectors and in our case we have four injector nozzles. It has three parts namely, Main rail, connection to the main fuel pump and four connection to the injectors nozzles. The material that is used to make this part must be able to withstand the high pressure of the fuel. This is probably an alloy of brass because brass is easily to machine, and it can withstand high pressure. The manufacturing processes for this part are machining and joining. The main rail is manufactured from a pipe that is either square or round that was made either through cold or hot rolling. The pipe is trimmed to the required size and the threads are made on one side by process called tapping using thread cutter, the threads should be the same as for the fitting that connects it to the pipe deliver fuel to it from fuel pump. The next step is to measure the location of the pipes feeding nozzles with fuel; they are four location that are equal or as per the location of the pistons. After location, the holes are drilled, and this process is called drilling and is done using bench drilling machine. Fittings that are compatible to the nozzles are then welded onto the holes that are already drilled, and this process is called joining. The fittings will enable easy connection of the main rail to the nozzle. When doing this manufacturing process the part is secured on the bench with vice. An alternative method to produce fuel injector rail is to machine using an advanced CNC machine whereby the materials is fed into the machine and programmed to machine it precisely. Part 9 – PISTON A piston is the engine component that is cylindrical and slides back and forth in the cylinder bore. It produces linear motion due to combustion, and the linear motion is converted into a circular motion in the crankshaft. The widely used material for the manufacture of the piston is a cast aluminum alloy because of its light weight and has good thermal conductivity. Thermal conductivity is the ability to conduct and transfer heat; this is very important because of a lot of heat that is produced during combustion. Small clearance should be allowed because aluminum expands when subjected to a lot of heat. The following is the calculation used to design the piston; Combustion chamber volume= deck height volume + head gasket volume +the volume of the dome hole in the piston 18.1=1.0895+3.6317+ the volume of the dome hole in the piston The volume of the dome hole in the piston=18.1-1.0895-3.6317 =13.3788 .This volume should be considered when making the piston. Diameter of the bore=diameter of the piston = 68mm Two process are used to produces the piston, namely; Casting and machining. The features that are produced include head, piston pin bore, ring grooves. Pistons rings that are used on this engine are compression ring, oil ring, and wiper ring. The mould which is in the shape of the piston head, with provision for dome hole in the head with a volume of 13.3788, and the piston pin bore is designed and produced using ceramics. Aluminum alloy is heated in a vessel or furnace until it melts or form liquid, it is then poured into the mould and left to solidify. Then removed and moved to the next stage of machining. The molded part is transferred to the milling machine and secured in the jaws.The outer surfaces of the molded piston are milled so that its diameter is nearly equal to the diameter of the bore, but it should have very small clearance. The depression or the dome in the piston head is spot faced to the required volume of 13.3788 cubic millimeters. Spot facing is the machining process whereby materials are removed from certain regions especially in forged or casted work. Reaming process is used to enlarge the pin hole to the required dimension. Reaming is the process of cutting a precise hole using a tool called reamer which a rotating cutting tool (Todd, Allen & Alting, 1994). Reamer can be used as hand tool or used on other machines like milling. Finally, the grooves for the rings are machined using the milling process The grove for the oil ring is slightly bigger as compared to the other two grooves. Summary of manufacturing processes that were used Conclusion The aims of the engine practical workshop was obtained and we were able to achieve the cumbustion ratio for honda Engine that is 8.1611. We also managed to come up with the materials and manufacturing process that can be used to produce the ford engine Reference Castro C.F. António C.A.C.and Sousa L.C, (2004) Optimisation of shape and process parameters in metal forging using genetic algorithms, Journal of Materials Processing Technology, 146(3), pp. 356–364. Degarmo, E. Paul; Black, J T.; Kohser, Ronald A (2003) Materials and Processes in Manufacturing, 9 edn.,: Wiley. Todd, R. H.; Allen, D. K.; Alting, L. (1994) Manufacturing Processes Reference Guide, : Industrial Press Inc. Read More