Group 6 - GM 4 Cylinder Engine - 1
The consumer product that was assigned to our group is the GM four cylinder 2.2 liter engine, which we found was manufactured at the GM Tonawanda Engine Plant. The purpose of this project is to gain a better understanding, through the disassembly, analysis, and reassembly, of the product. By dissecting the engine each component could be seen individually as well as how the parts interact and work together as a system.
The first main step was disassembling the engine. During this process, we carefully recorded each step, including the tools used and the difficulty of each step. As the parts list was being compiled each component was analyzed, documenting what material each component was made of, how each was manufactured, and what the function of each component was.
After the disassembly, certain components were selected and modeled digitally using various software packages including Autodesk Inventor, Pro-E, and Solidworks. Some of the parts that were modeled included the Piston/Connecting Rod system, Camshaft, and Oil Pump Drive Gear.
After all the necessary information was collected the engine was reassembled. The process for reassembly was basically the same as disassembly, with a few minor changes. Following reassembly normally the engine would be tested to make sure that it still worked, but it could not be tested for functionality because certain parts had cutouts, to show the functionality for those components. If it had been required to have the engine be functional, gaskets would have had to been replaced, all bolts would have had to been tightened to the proper torque, and the cutout parts would have had to be replaced with new components.
After we had learned about how the engine worked, and how the components related to one another, we were able to make recommendations on what components/systems could be improved upon. Improvements focused in on having the engine being able to generate more power, as well as having parts be more effective in their function.
Overall, this was a very valuable experience, working hands-on learning about the product, as well as working in a group towards the goal of obtaining a better understanding of how the product functioned.
Group Members and Responsibilities
- Brian Dolan - 3D Modeling, Disassembly, Reassembly, Presenting
- Rob Jones - Disassembly, Reassembly, Report Writing
- Dave Brookes - Disassembly, Reassembly, Report Writing
- John Scheda - 3D Modeling, Disassembly, Reassembly, Report Writing
- Eric Malinowski - Disassembly, Reassembly, Report Writing
- John Schiavone - Disassembly, Reassembly, Report Writing, Presenting
- Jerad Henderson - Disassembly, Reassembly, Report Writing
- Jung Lee - 3D Modeling
- Keelan Chufor - Report Writing, Disassembly
- Ryan Lee - Reassembly, Report Writing
- Manufacturer: General Motors
- Class: Inline Four Cylinder
- Displacement: 2.2 Liters
- Serial Number: 24576035
- Assembled in Tonawanda GM Engine Plant
- Condition: Non-working, multiple parts have been cut open to show functionality.
The purpose of the GM 2.2 Liter 4 Cylinder Engine is to generate the power needed to drive a small automobile. It is an internal combustion engine, which takes the potential and chemical energy stored in gasoline and turns it into the mechanical energy necessary to power a vehicle. This is done by combusting the air and fuel mixture in a cylinder, which in turn forces a piston downward. That piston is connected to a crankshaft and flywheel, which connect the transmission, the drivetrain and the wheels. There are four steps to the combustion process. The first is the intake, in which the piston moves down in the cylinder, drawing fuel and air into the cylinder. The next step is the actual compression of the fuel and air mixture, in which the piston moves upward towards the top of the stroke, and the spark plug ignites the fuel/air mixture. This ignition of the mixture is known as the combustion stroke, in which the piston moves back down in the cylinder due to the force of the explosion. The final stroke in the process is the exhaust stroke, in which the exhaust valves open, allowing the result of the combustion to exit the cylinder. This four step process can be repeated thousands of times in a minute, creating energy for the transmission to harness, which will in turn power the drive wheels of the vehicle.
The engine was not operating when we received it, and is believed to be made of roughly 1000 components. We anticipated the engine to be made up of the following materials; Cast Iron, Steel, Aluminum, Brass, Alloys, Plastic, and Rubber.
1. Removed (3) plug wires from spark plugs with hands. (Easy)
2. Removed (2) bolts holding plug wires to valve cover. (Easy) (10 mm socket)
3. Removed (2) bolts with distributor. (Easy) (10mm socket)
4. Removed (5) bolts with distributor bracket. (Easy) (8 mm socket)
5. Removed (8) bolts with valve cover. (Moderate) (10 mm socket)
6. Removed (12) oil pan bolts. (Easy) (10 mm socket)
7. Removed oil pan by hand. (Easy)
8. Removed (4) nuts with exhaust. (Moderate) (13 mm socket)
9. Removed (1) bolt oil filler/dipstick. (Easy) (15 mm socket)
10. Removed (2) with coolant tube. (Easy) (13 mm socket front, 15 mm socket back)
11. Removed oil filter by hand. (Easy)
12. Removed throttle body cover by hand. (Easy)
13. Removed (2) bolts with fuel rail. (Easy) (10 mm socket)
14. Removed (2) nuts and (1) bolt from intake. (Easy) (13 mm socket)
15. Removed (4) bolts with throttle body. (Easy) (10 mm socket)
16. Removed (2) bolts with coolant thermostat. (Easy) (13 mm socket)
17. Removed (4) bolts with front motor mount and gasket. (Moderate) (13 mm socket)
18. Removed (3) bolts with water pump pulley. (Easy) (13 mm socket)
19. Removed (3) bolts with water pump. (Easy) (13 mm socket)
20. Removed (1) bolt with part 31, sensor. (Easy) (16 mm socket)
21. Removed (4) bolts with crankshaft pulley. (Easy) (Three 16 mm sockets, One 18 mm socket)
22. Removed (6) bolts from timing chain cover. (Moderate) (8 mm socket)
23. Removed (8) rocker arms, (1) bolt each. (Easy) (10 mm socket)
24. Loosened (10) head bolts. (Easy) (15 mm socket)
25. Removed head from block by hand. (Easy)
26. Removed 8 pushrods by hand. (Easy)
27. Removed head gasket by hand. (Easy)
28. Removed (1) bolt with serpentine belt tensioner. (Moderate) (15 mm bolt)
29. Removed (1) bolt with oil pump. (Easy) (15 mm socket)
30. Removed (2) bolts from bottom of connecting the rod and then the piston from cylinder #2. (Moderate) (14 mm socket)
31. Removed (2) bolts from bottom of the connecting rod and then the piston from cylinder #3. (Moderate) (14 mm socket)
32. Removed (2) bolts from bottom of the connecting rod and then the piston from cylinder #1. (Moderate) (14 mm socket)
33. Removed (2) bolts from bottom of the connecting rod and then the piston from cylinder #4. (Hard) (14 mm socket)
34. Removed (4) journal bearing housings, (2) bolts. (Moderate) (15 mm socket)
35. Removed timing chain sprocket and bolt. (Hard) (1 inch socket)
36. Removed crankshaft, timing chain cover and chain by hand. (Hard)
37. Removed gasket (holding cam) and two torque heads. (Moderate) (T30)
38. Removed oil pump timer and (1) bolt. (Moderate) (10 mm socket)
39. Removed (2) plastic lifter trays, (1) bolt each. (Easy) (10 mm socket)
40. Removed (8) lifters by hand (turned camshaft to lift them). (Moderate)
41. Removed camshaft by hand. (Easy)
The CAD files can be downloaded here. Note that this archive does not contain all of the CAD files used in this project.
Engine Parts List
|Part #||Part Name||Qty||Material||Manufacturing Process||Function||Why the Material Composition||Image|
|1||Spark Plug Wires||1||Rubber/Carbon-impregnated fibers||Injection Molded||Sends the electricity from the coil packs to the spark plugs, which in turn ignites the air/fuel mixture.||Rubber insulates the wire fibers so electricity doesn't jump to the other metal components under the hood; fibers are capable of conducting pulses of high voltage electricity.|
|1a||Bolts (10 mm)||2||Steel||Machined||Keeps component in place.||Steel has high tensile strength for fastening and high resistance to corrosion for infinite cycles of use.|
|1b||Spark Plug||1||Porcelain/Steel||Formed||Ignites the air/fuel mixture.|
|2||Distributor||1||Thermoset Plastic||Molded||Sends the electricity to the spark plugs in the correct sequence and timing.||Plastic insulates the plug contacts and the rotor and from the car body; inexpensive.|
|2a||Distributor Bracket||1||Aluminum||Die Cast/Machined||Holds the distributor.||Lightweight and strong.|
|2b||Distributor Gasket||1||Treated Fiber Sheet||Die Cut||Helps hold the distributor off of the block.||Treating results in strong ILSS for resisting any abrasion from the block and the distributor.|
|2c||Coil Packs||2||Material||Cast and Machined||Spin inside distributor to hit contacts and complete electric flow to spark plugs.|
|2d||Bolts (7/32 in)||4||Steel||Extruded and Machined||Keep component in place.||Steel has high tensile strength for fastening and high resistance to corrosion for infinite cycles of use.|
|3||Valve Cover||1||Aluminum||Die Cast/Machined||Seals the top of the engine and the vacuum in the engine.||Lightweight and strong.|
|3a||Bolts (10 mm)||8||Steel||Extruded and Machined||Keep component in place||Steel has high tensile strength for fastening and high resistance to corrosion for infinite cycles of use.|
|3b||Head Gasket||1||Mulitple Layered Steel||Stamped||Fits between block and head to help seal cylinders.|
|4||Oil Pan||1||Steel||Stamped/Welded/Painted||Acts a reservoir for the engine oil.||For durability.|
|4a||Bolts (10 mm)||12||Steel||Extruded and Machined||Keep component in place.|
|5||Exhaust Manifold||1||Cast Iron||Cast/Machined||Guides the exhaust gases out of the cylinders and into the exhaust pipe.||Easily machined; wear resistant.|
|5a||Nuts (13 mm)||4||Steel||Machined||Keeps the component in place.|
|5b||Oxygen Sensor||1||Plastic/Aluminum/Electronics||Machined and Assembled||Emissions test for the exhaust gases.|
|6||Oil Fill Tube||1||Steel||Rolled/Stamped/Welded||Pipe to oil reserve to fill oil when oil becomes old.||Durability.|
|6a||Dip Stick||1||Steel/Plastic||Molded/Stamped||Used to check the level of oil within the oil pan.||Cheap, used only as a measuring device.|
|6b||Bolt (15 mm)||1||Steel||Extruded and Machined||Keep component in place.|
|7||Crankcase Vent Tube||1||Steel||Extruded/Formed/Welded||Used to manage gases/vapors in the crank case.||Steel is a good thermal conductor, moisture doesn't condense once the tube heats up.|
|7a||Nut (13 mm)||1||Steel||Machined||Keeps the component in place.|
|7b||Nut (15 mm)||1||Steel||Machined||Keeps the component in place.|
|7c||Coolant Temperature Sensor||1||Plastic/Aluminum/Electronics||Molded/Machined/Assembled||Checks temperature of the engine.|
|8||Fuel Rail||1||Stainless Steel||Extruded/Formed/Welded||Takes the fuel from the fuel lines and distributes the fuel to the injectors.||Withstands corrosion and high pressures.|
|8a||Bolts (10 mm)||2||Steel||Machined||Keep component in place.|
|8b||Injectors||4||Steel/Plastic||Molded/Machined||Takes the fuel from the fuel rail and sprays it into the cylinders at the correct time.|
|9||Throttle Body||1||Aluminum/Brass/Plastic/Plated Steel||Die Cast/Molded/Machined/Stamped/Extruded/Pressed||Regulates the amount of air entering the intake manifold.||Aluminum valve is lightweight, and has fast response time; plastic insulates throttle position sensor + wiring; steel body withstands high pressure and corrosion.|
|9a||Bolts (10 mm)||4||Steel||Machined||Keeps component in place.|
|10||Thermostat Housing/Coolant Line||1||Aluminum||Sand Cast/Machined||Delivers coolant to the engine and monitors the temperature.||Strong, Cheap, and Lightweight.|
|10a||Bolt (13 mm)||2||Steel||Machined||Keeps component in place.|
|10b||Thermostat Housing Gasket||1||Treated Fiber Sheet||Die Cut||Treating results in strong ILSS for resisting any abrasion from the block and the distributor.|
|10d||Water outlet||1||Steel||Formed Welded||Lets water and coolant mixture out of sensor.|
|11||Water Pump Pulley||1||Steel||Stamped/Painted||Drives the water pump.||Easy to manufacture; Strong; Long life.|
|11a||Bolts (13 mm)||2||Steel||Machined||Keeps component in place.|
|12||Water Pump||1||Aluminum/Steel||Die Cast/Machined/Stamped/Pressed||Pump water/coolant mixture throughout the motor.||Easy to Manufacture; Strong; Long Life.|
|12a||Bolts (13 mm)||3||Steel||Machined||Keeps component in place.|
|13||Front Motor Mount||1||Cast Iron||Sand Cast/Painted/Machined||Attaches the motor into the engine bay of the car.||Easily cast and machined; Long Life.|
|13a||Bolts (13 mm)||4||Steel||Machined||Keeps component in place.|
|13b||Idler Pulley||1||Steel||Molded||Keeps the tension in the serpentine system.|
|14||Vacuum Sensor||1||Plastic/Steel||Molded/Stamped||Monitors/controls vacuum distribution.||Plastic insulates electronic parts; steel strong durable and holds the sensor.|
|14a||Bolt (15 mm)||1||Steel||Machined||Keeps the component in place.|
|15||Timing Chain Cover||1||Aluminum||Die Cast/Machined||Protects the timing chain from debris.||Cheap, lightweight, and cast to fit.|
|15a||Bolts (8 mm)||6||Steel||Machined||Keeps the component in place.|
|15b||Timing Chain Cover Gasket||1||Treated Fiber Sheet||Die Cut||Seals the cover to the block.||Treating results in strong ILSS for resisting any abrasion from the block and the distributor.|
|16||Timing Chain||1||Steel||Stamped/Pressed/Riveted||Keeps the crankshaft and camshaft in time.||Stamped to increase strength and durability, high life cycle.|
|17||Rocker Arms||8||Steel||Forged||Open and close the valves based on the input from the pushrods via the camshaft.||Forged is stronger than cast steel, reciprocating weight, and more durable for high life cycle; good balance of cost and weight.|
|17a||Rocker Arm Bolts (10 mm)||8||Steel||Machined||Keeps component in place.||Durable.|
|17b||Rocker Arm Bearings||16||Steel||Machined/Ground||Keeps component in place.||Durable.|
|17c||Rocker Arm Bracket||8||Steel||Machined/Sand Cast||Keeps component in place.||Easily cast and machined, durable.|
|17d||Rocker Arm Shaft||8||Steel||Machined/Ground||Shaft.|
|18||Cylinder Head||1||Aluminum||Cast/Machined||Contains the entire rocker arm valve assembly and top of the cylinder where the combustion takes place.||Strong, lightweight, and durable; Cast to specific engine model.|
|18a||Head Bolts (15 mm)||10||Steel||Machined||Keeps the components in place.|
|18b||Valve Springs||8||Steel||Formed/Heat Treated/Plated/Ground||Keeps tension on the valves to keep them closed until opened by timing assembly from camshaft.||Strong, and durable.|
|18c||Valve Spring Cap||8||Steel||Machined||Keeps the components in place.||Strong, easy shape to manufacture.|
|18d||Valve Spring Retainers||16||Steel||Machined||Keeps the components in place.||Strong and durable.|
|18e||Inlet Valve||4||Steel||Forged/Spun/Machined||Opens to let fuel and air mixture into cylinder.||Strong, and durable.|
|18f||Exhaust Valve||4||Steel||Forged/Spun/Machined||Opens so that exhaust can exit cylinder.|
|19||Push Rods||8||Steel||Extruded/Ground/Welded||Connects the camshaft to the rocker arms.||Strong, and durable.|
|20||Serpentine Belt Tensioner||1||Plastic/Aluminum/Steel||Die Cast/Molded/Machined||Keeps tension on the serpentine system.||Strong, cheap, and lightweight.|
|20a||Bolt (15 mm)||1||Steel||Machined||Keeps component in place.|
|21||Journal Bearings||5||Metal Alloy (Babbit)||Extruded/Bent/Machined||Keeps the crankshaft, bearing housings, and the block from wear while allowing rotation in the crankshaft.||Easily cast and machined; durable.|
|21a||Bearing Bolts (15 mm)||10||Steel||Machined||Keeps the component in place.|
|21b||Journal Housing||5||Steel||Cast/Machined||Holds journal bearings and supports crankshaft.|
|22||Piston||4||Aluminum||Die Cast/Machined||Movement is controlled by the crank shaft, allowing the cylinders to perform the combustion process.||Strong, durable, and lightweight for fast reciprocating motion; machined to specific size and shape.|
|23||Piston Assembly||4||Aluminum||Die Cast/Machined||Converts the power of the combustion to the crankshaft, converting heat to mechanical energy.|
|23a||Connecting Rod Cap||4||Iron||Sand Cast/Machined||Fits around crankshaft, keeping the connecting rod on crankshaft while allowing rotation.|
|23b||Connecting Rod||4||Steel||Forged/Bead Blasted/Machined||Connects the piston to the crank shaft.|
|23c||Connecting Rod Bolts||8||Steel||Machined/Plated||Holds the component in place.|
|23d||Connecting Rod Nuts||8||Steel||Machined/Plated||Holds the component in place.|
|23e||Connecting Rod Bearing Halves||8||Steel/Bronze/Babbit||Formed/Plated||Provides smooth surface for low friction and repetitive motion.|
|23f||Wrist Pin||4||Steel||Extruded/Ground/Pressed||Connects the piston and Connecting Rod.||Durability for constant motion.|
|23g||Oil Ring||4||Steel||Stamped||Keeps the cylinder lubricated for a low friction environment.||Durability and strength from constant use.|
|23h||Compression Rings||8||Iron||Cast/Machined||Keeps compression in the cylinder.||Durability for constant use.|
|24||Timing Chain Sprocket||1||Iron||Cast/Machined||Connects the timing chain to the camshaft.||Easily cast and machined.|
|24a||Bolt (15/16 in)||1||Steel||Machined||Keeps component in place.|
|25||Crank Shaft||1||Iron||Cast/Machined||Takes the mechanical energy from the pistons and transfers it to the transmission.||Easily cast and machined; Durable.|
|26||Gasket (holding Camshaft)||1||Steel||Machined||Hold the camshaft in the engine and helps to seal it.|
|26a||Torqueheads (30)||2||Steel||Machined||Fastens gasket to block.|
|27||Oil Pump Drive Gear||1||Aluminum/Steel/Rubber||Cast/Extruded/Machined/Molded||Drives the oil pump based on input from the camshaft.||Strong, lightweight, and ease of manufacture.|
|27a||Bolt (10 mm)||1||Steel||Machined||Keeps the component in place.|
|28||Lifter Trays||2||Plastic||Molded||Holds the lifters in place under the push rods.||Cheap, durable.|
|28a||Bolts (10 mm)||2||Steel||Machined||Keeps the component in place.|
|29||Lifters||8||Steel||Cast/Machined/Hardened||Lifted by lobes on the camshaft to deliver energy to pushrods.||Strong; Durable; Machine shaped to articulate accurately with pushrods and camshaft.|
|30||Camshaft||1||Iron||Cast/Machined/Hardened||Rotates in the engine block, controlling the pushrods and the opening and closing of the valves. Also
controls other aspects of timing in the engine.
|Easily cast and machined. Material is durable because of constant use.|
|31||Intake Manifold||1||Plastic/Brass||Molded/Machined/Pressed||Takes the air let in by the throttle body and delivers it to the cylinders when the valves are open.||Cheap and lightweight; brass threads are machined to fasten strongly to engine.|
|31a||Nuts (13 mm)||2||Steel||Machined||Keeps the component in place.|
|31b||Bolts (13 mm)||2||Steel||Machined||Keeps the component in place.|
|31c||Bolts (13 mm)||3||Steel||Machined||Keeps the component in place.|
|31d||Spacers||3||Steel||Machined||Holds the intake away from the engine head.|
|32||Oil Filter||1||Steel/Paper||Stamped/Rolled/Welded/Machined/Painted||Filters the oil to prevent debris from getting moved through the engine.||Vast materials used to ensure debris doesn't enter the engine.|
|32a||Oil Pressure Sensor||1||Steel/Plastic/Electronics||Molded/Machined/Pressed||Makes sure engine is running with the proper oil pressure.|
|33||Belt Drive Wheel||1||Steel||Cast||Pulley that connects to the crankshaft.||Ease of manufacture.|
|34||Engine Block||1||Iron||Cast/Machined||Holds everything together, and forms the majority of the cylinders.||Easily cast and machined. Very durable.|
The engine is made out of many different materials including, but not limited to, steel, aluminum, iron, rubber and plastic. Over the course of an engine’s life, it is subjected to high temperatures, high stress, and for some parts, continuous motion and work while the engine is running. Steel (fasteners) and iron (engine block, exhaust manifold, crankshaft, and camshaft) were used for many parts because they are easy to cast and machine. They are also durable metals that can withstand stress and high temperatures. Aluminum (cylinder head, valve cover, piston, and timing chain cover) was used for many parts because it is lightweight while still being durable and strong. No major parts were made out of plastic, but there were a few pieces that used plastic away from the high engine stresses and temperatures. Plastic is cheap to use and easy to mold. Rubber (spark plug wires and gaskets) is used because it can be easily molded, is flexible and is a good insulator for wires. Rubber used for gaskets and other seals is able to effectively seal two pieces together.
|Part Name||CAD Image|
|Connecting Rod Part 1|
|Connecting Rod Part 2|
|Air Pump Pulley|
|Oil Pump Drive Gear|
Piston Assembly Video
This is a video of the Piston/Connecting Rod system being assembled in Autodesk Inventor.
1. Replaced camshaft by hand. (Easy)
2. Replaced (8) lifters by hand. (Easy)
3. Replaced (2) plastic lifter trays, (1) bolt each. (Easy) (10 mm socket)
4. Replaced oil pump timer with (1) bolt. (Easy) (10 mm socket)
5. Replaced gasket (holding cam) and two torque heads. (Moderate) (T30)
6. Replaced crankshaft, timing chain cover and chain by hand. (Hard)
7. Replaced timing chain sprocket and bolt. (Hard) (1 inch socket)
8. Turned cam, then replaced the four pistons/connecting rods using the ring compressor. (Moderate)
9. Replaced (2) bolts with bottom of connecting rod to cylinder #2. (Moderate) (14 mm socket)
10. Replaced (2) bolts with bottom of connecting rod to cylinder #3. (Moderate) (14 mm socket)
11. Replaced (2) bolts with bottom of connecting rod to cylinder #1. (Moderate) (14 mm socket)
12. Replaced (2) bolts with bottom of connecting rod to cylinder #4. (Hard) (14 mm socket)
13. Replaced (4) journal bearing housings, with (2) bolts each. (Moderate) (15 mm socket)
14. Replaced the oil pump, with (1) bolt. (Easy) (15 mm socket)
15. Replaced the head gasket by hand. (Easy)
16. Replaced head with (10) bolts. (Easy) (15 mm socket)
17. Replaced (8) pushrods by hand. (Easy)
18. Replaced (8) rocker arms, (1) bolt each. (Easy) (10 mm socket)
19. Replaced the motor mount gasket by hand. (Easy)
20. Replaced front motor mount with (4) bolts. (Easy) (13 mm socket)
21. Replaced (2) nuts and (1) bolt from intake. (Easy) (13 mm socket)
22. Replaced (4) bolts with throttle body. (Easy) (10 mm socket)
23. Replaced the pulley tensioner with 1 bolt. (Easy) (15 mm socket)
24. Replaced (5) bolts with distributor bracket. (Easy) (8 mm socket)
25. Replaced (2) bolts with distributor. (Easy) (10 mm socket)
26. Replaced crankshaft pulley and (4) bolts. (Easy) (Three 16 mm socket) (One 18 mm socket)
27. Replaced water pump and pulley together, (3) bolts each. (Easy) (13 mm socket)
28. Replaced the valve cover with (8) bolts. (Easy) (10 mm socket)
29. Replaced coolant thermostat with (2) bolts. (Easy) (13 mm socket)
30. Replaced part 31, sensor, with (1) bolt. (Easy) (13 mm socket)
31. Replaced fuel rail with (2) bolts. (Easy) (10 mm socket)
32. Replaced oil filter by hand. (Easy)
33. Replaced (2) nuts and coolant tube. (Easy) (13 mm socket front) (15 mm socket back)
34. Replaced (4) nuts with attach exhaust. (Easy) (13 mm socket)
35. Replaced oil filler / dipstick with (1) bolt. (Easy) (15 mm socket)
36. Replaced oil pan with (12) bolts. (Easy) (10 mm socket)
37. Replaced (3) plug wires from spark plugs and coil, replaced (2) bolts holding plug wires to valve cover. (Easy) (10 mm socket)
How It Works
- The engine block is physically the iron body that an engine is built around. It consists of networks for oil and anti-freeze and houses all pistons, cylinders, crankshaft, camshaft and push rods. This particular engine block has four cylinders in a linear pattern, hence "in-line 4" but other engines come in "V or W" patterns. The head and oil pan bolt directly onto the engine block. Any amount of friction dramatically reduces the efficiency of the engine thus the engine block is lubricated with motor oil.
- Pistons- Within each of the four cylinders, there is a piston fitted precisely to the dimensions of the cylinder. The fit needs to be precise so that no energy is lost through a bad seal. The combustion of the fuel and air mixture occurs here and creates a force that sends the piston down the cylinder, thus continuing the rotational motion of the crankshaft.
- Crankshaft- The crankshaft is attached in four separate locations to each of the four pistons by long connecting rods. It is designed so that 2 cylinders are moving in unison, and vary with the other two. A further look reveals that although two are moving in unison, they are functioning oppositely in the four step combustion process. This is done so that each cylinder "fires" without a break in timing. When done thousands of times a minute, you cannot hear each individual fire. At one end, the crankshaft connects to the flywheel and the other end connects to the camshaft through what is called the timing chain.
- Camshaft- The camshaft is similar in design and function to the crankshaft. For each cylinder the camshaft has two connections, opposite each other. This engine utilizes a pushrod cam system, but other systems commonly used are the double overhead cam and single overhead cam. Pushrods link the camshaft to valves (two per cylinder) via valve lifters. It is responsible for the opening and closing of the valves to each cylinder. Valve lifters lift or open one set of valves when the intake stroke begins and close when it ends. The fuel is then combusted, when the power stroke ends, and the exhaust stroke begins, the second set of valves open in order to release the combusted gas. The timing chain connects the camshaft to the crankshaft so that the valves and pistons always operate in sync.
- The intake manifold has the job of drawing in the air, which in turn is mixed with fuel and combusted in the cylinders. As more or less acceleration is desired, the intake opens/closes respectively, in order to provide this change in speed. In plain English, when the driver steps on the accelerator, the throttle body opens wider to let in more air. Earlier versions of the engine incorporated a carburetor which mixes the fuel and air before entry into the cylinder. They were phased out because of their bad fuel efficiency.
- Superchargers use power from the serpentine belt system to turn a compressor which compresses the air before it enters the engine. This allows for a higher compression in the engine cylinder which allows for greater power.
- Turbochargers take air from the exhaust gas and send it back to the engine thus giving the same result as a supercharger.
- Every engine needs an exhaust system to get rid of the combustion products as they are pumped out of the cylinder. This particular engine was built with an exhaust manifold, meaning all four cylinders drain exhaust gas to a common chamber, where an exhaust pipe then transports it to the surrounding environment. Manifolds are extremely common but another exhaust design called headers are more beneficial to performance and customizing. Not all of these products are harmless, which is why all modern exhaust systems incorporate a catalytic converter. This is a chamber containing highly reactive metals in a honeycomb pattern designed to catch these products as they pass through, thus burning off any unwanted chemicals left from combustion.
- The head, which bolts directly on the top of the engine block, is an extremely complicated assembly of components. It houses the springs, pushrods, valves, and rocker arms. As the camshaft spins, one valve lifter will be raised, raising a pushrod, thus raising one side of the rocker and consequently opening the corresponding valve. The lifter then falls back into place as the camshaft continues to spin. The rocker is now flat and the spring closes the previously opened valve. Now the opposite valve lifter is raised, as well as the corresponding pushrod and rocker arm. This opens the opposite valve temporarily, allowing combustion products to escape, until the lifter falls and the spring forces the valve shut. This process is done for all four cylinders and timed so they perform the correct task when necessary.
Analyses For Design and Testing
There are many different types of models that can be used to analyze the engine and its components. The following is an example of a model that could be used to analyze the efficiency of the engine.
When analyzing efficiency, the first thing that needs to be looked at is the energy input as compared to the energy output. Say 10,000 Joules of energy is created through the combustion of gasoline, and 4000 Joules of that initial ten thousand is transformed into mechanical energy. That means the engine is only 40% efficient. The other 6000 Joules is transformed into heat energy, and needs to be disposed of so the engine doesn’t overheat while in use.
The analysis of the engine and how much heat is given off is then used in the calculations of how to remove the heat from the engine/car system. There needs to be a heat transfer process to cool the engine back down. Initially, coolant flows through the engine block, and is heated up. The heat still needs to be disposed of, so this is where the radiator becomes important. The radiator is composed of very thin aluminum sheets, placed close together. The sheets are formed into tubes or channels, through which the coolant flows through. In order to maintain an efficient system, the surface area for the aluminum sheets needs to be maximized so that all of the heat that was transferred to the coolant is disposed of, and that the coolant is a lower temperature when it flows back into the engine block. The radiator is placed in the front of the car, behind a grill so it doesn’t take any damage, but so that the air passing over the tubes/channels removes heat from the coolant.
This is an example of a basic engineering model. To fully analyze a system as complex as an engine, sophisticated equipment is needed. The best models are created through actual testing of the engine. Mathematical models are only fully accurate in an ideal setting, and do not account for stresses and strains of the real life system. Some examples of practical models include component testing, full system testing, engine life test, and efficiency tests.
The disassembly and reassembly processes were similar but not exactly reversible. For example during disassembly we started at the top of the engine and moved downward. However during reassembly we were making an effort to put components back on that did not obstruct the assembly of other components. The oil pan was step six of the disassembly procedure, but was the second last step of reassembly. The same sets of tools were used during both processes. Reassembling the product was more difficult than the disassembling process because we made deviations from the disassembly procedure. After counting the parts after disassembly and before reassembly, we found our estimate of 1000 parts to be very high. The actual amount of parts was 240.
The design changes we would recommend on the product level would be to switch the material of the engine from cast iron to cast aluminum because it would weigh less and reduce corrosion concerns. Cast iron was chosen because it's the least costly among rigid metals but as far as functionality aluminum is more desirable. Additional design changes are listed and explained in detail below.
Camshaft Lobe Design
The lobes on the camshaft control how long the valves are open for, so if the lobe size was changed, thus would the performance of the engine. If the valves were open longer, more power would be generated.
Variable Camshaft Timing
Ultimately, rather than change the camshaft, the best design change would come from changing the timing of the camshaft with the crankshaft. This camshaft in this particular engine was designed so that it works in time with the crankshaft, the timing being controlled by the timing chain. Variable camshaft timing may require some redesign of the engine and its components, but it offers a wide range of possibilities. The timing could be computer controlled, allowing for the valves to be open for a longer period of time when accelerating, to provide more power. The valves would then go back to being closed for a set period of time when driving at a constant speed.
The main change that we would suggest GM look into would be switching the engine from an in-block cam to an overhead cam system.
Pushrods vs. Overhead Cam
This is an animation of the pushrods opening and closing the valves using input from the camshaft
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Animation of single overhead cam
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-Pushrods and overhead cams (OHC) are two different valve trains, ways of transferring the motion of the cam shaft to the rocker arms to open and close the valves.
-Pushrod engines add more parts to the system that opens and closes the valves, lifters and pushrods. If one were to move the camshaft to the top of the cylinder head, they could use the lobes on the camshaft to push the rocker, which would in turn open and close the valves.
-An OHC design decreases play, or “float”, in the system and allows for a lighter and more precise valve train.
-The lighter and more precise valve train in an OHC configuration decreases power lost due to the valve train.
-OHCs can be simpler to design in future redesigns of the engine.
-An OHC system would require a redesign of, or modification to, the cylinder head, block, timing system, oil pump power system, and possibly camshaft.
SOHC vs DOHC vs Pushrod Engines: Camshaft Issues. Retrieved November 30, 2008, from Web site:
HowStuffWorks - Learn How Everything Works!. Retrieved November 16, 2008, from Web site: