Gate 1 - Request for Proposal
Our group has been assigned a General Motors six cylinder engine, shown in Figure 1. In order to reverse engineer our motor we plan to start by taking photos and recording the position of everything on the motor, as is. We will start by removing any subsystems such as electrical wiring harness, air intake system, exhaust systems, starter motors, charging systems, and the ignition system if they are present. This will be done by loosening any bolts that connect the subsystems to each other or to the engine block and heads. Also some sensors, like those on the intake manifold, will have clip connectors. These connectors and other sensors will have to be taken apart with extreme care as not to break them. With all bolts loosened and sensors removed, we should be left with the engine block with rotating assembly inside, and the cylinder heads, complete with valve train intact.
From only inspection of the exterior we plan to next, take apart the valve train. This will first consist of the removal of the cylinder heads from the engine block. After having loosened the bolts on the head studs, the entire cylinder head assembly can be removed and put on a work bench area in order for easier dissection. With the cylinder head right side up, the rocker arms must be removed to get into the rest of the valve train, this will be done with either a socket wrench or Allen wrench depending on the bolt. The next step is to use the valve spring compressor to compress to valve springs, allowing for removal of the valve seats and retainers depending upon the valve train design.
In order to successfully dissect our automobile engine, we have decided to give certain positions to each person in our group. With these positions well be able to identify the specific roles of each person in our group. But even though a specific role is given to a person, we will all try to work an equal amount on the project so that we produce a report of high quality. The roles of each person are as follows.
and Tanner Kahn
|Matthew Egan||Technical Report Editor||
|Samuel Kim||Communication Liason||
- E-mail- firstname.lastname@example.org
- Phone number- 845- 645- 0702
|Jasmine Lawrence||Project Manager||
In order to complete the project in a timely fashion we have decided to meet twice a week on Tuesday and Thursday in the Capen Library or in the lab located at Furnas 621. If more meetings are needed we will schedule them accordingly with everyone’s schedule. The plan during the labs is to dissect the engine as efficiently as possible while learning about each subsystem noted in the Product Proposal (rotating assembly, valve train, energy transformation systems, engine control systems). We will be starting with the top of the engine taking apart each section of the head and then the block so we can view the inner parts of the engine. First, we will look at the main rotating assembly and how the crankshaft works with the connecting rods, pistons. After this, we will move to the valve train and look at the camshafts, valves and several other components in this system. And then we will move on to observe the energy manipulation components of the engine like the water and oil pumps and alternator. During our meetings and time in labs, we will complete the dissection of the engine while learning about each system and subsystems as well as re- assembling the engine in the state given to us. If there is a conflict within the group, we will all come together and discuss the issue that is at hand and we will handle it in a fair, democratic way that would hopefully do away with the problem within the group.
The following outline is a schedule of our planned meetings:
Gate 2: Due 10/26/11
- October 11th , 13th , 18th and 21st
Gate 3: Due 11/14/11
- November 1st , 3rd and 10th
Gate 4: Due 12/2/11
- November 17th (21st if necessary) and 29th
Gate 5: Due 12/16/11
- December 6th and 8th
At each of these meetings we will work to accomplish as much as possible, especially in the lab, so that we can meet the requirements of each gate in a timely fashion. We will continue to communicate effectively via email, text messaging and phone calls to solve any possible conflicts as well as answering any questions that may arise in the whole project.
The Vortec 4300 which was based off the Chevrolet small-block v8, was developed by General Motors in the 1980’s. During the 1960’s, American vehicle manufacturers had a large focus in their performance cars, or muscle cars. Their goal was to create as much power as possible in light weight, two-door cars. This resulted in the three major car corporations, designing engines with large displacements. These engines not very fuel efficient, but this was not much of a concern at this time. During the 1980’s the car manufactures began focusing on producing more fuel efficient engines. This can be done by decreasing the number of cylinders, and with that, the displacement. GM designed a 4.3 Liter, six cylinder engine for use in light duty trucks and SUV’s. This engine produced enough horsepower and torque to be a feasible option for use, but also increased the fuel efficiency. This allowed consumers to continue their usual usage, but use less fuel. The 4.3 Liter, six cylinder, or Vortec 4300, was also cheaper to manufacture than a larger eight cylinder engine due to less material needed, as well as less internal parts. Because of these characteristics, it was offered in more than ten vehicles available in North America. Through its lifespan of more than 15 years, it went through a few minor design alterations but the same design remained the same.
The General Motors Vortec 4300 engine was typically an engine design for small to medium sized trucks, sport utility vehicles, and vans but also made some appearances in large passenger sedans. The wide range of vehicles it was used in portrays the engine's versatility in the automobile market. Being put into generally larger vehicles, the engine has a higher output (around 200 horsepower depending on the model) than smaller four cylinder engines. This shows that the intended use of the engine was to provide sufficient power to these larger vehicles. The engine also had a high specific torque in order to haul loads in the given vehicle as well as to provide an acceptable rate of acceleration in heavier consumer vehicles. This engine was designed for use in typical consumer automobiles, but also had some usage in different professional machinery. This is evident in the tasks it can perform better than some other engines, such as towing or hauling loads. Due to the Vortec's high torque, along with its' wide torque band, the engine can handle extended periods of high load such as those experienced during towing. The engine also does this while being more economical than a typical eight cylinder engine.
In the Vortec 4300, the electrical system is a major contributor to the overall operation as shown in Figure 2. Most modern engines have very technologically advanced systems to control and monitor various operations of the engine. These are all controlled by electricity which is provided by the battery. Electrical energy is used to communicate different conditions to the engine's computer, also known as an engine control unit or power train control module. Communication is essential for the engine's computer to monitor and then adjust different systems of the engine accordingly for optimal operation. The electrical system includes the engine control unit, all of the sensors used to monitor engine operation (knock, air fuel ratio, camshaft, crankshaft, mass air flow, manifold air pressure, and temperature sensors) as well as the alternator. As a whole the electrical system is responsible for complete control and monitoring of the engine. The overall function of an engine is to create rotational energy. The system directly involved in this conversion would be the rotating assembly of an engine. The rotating assembly consists of the pistons, piston rings, connecting rods, pins, crankshaft, and bearings. In this subsystem the energy of the gasoline is released along with the heat energy of the ignition and energy of the air in the form of a combustion. Called the Otto Cycle, the combustion phase causes the piston to then have linear motion, which is converted to the rotational energy of the crankshaft. Along with the rotational energy created, heat energy is also created but not for any use of the engine. The rotational energy of the crankshaft that is created is used by other subsystems as shown in Figure 2. The amount of rotational energy created depends on a number of factors within the rotating assembly of an engine. For energy to enter the rotating assembly system, it must first pass through the valve train. The valve train includes all of the mechanical systems of the cylinder head, which are the camshafts, , rocker arms, intake valves, exhaust valves, valve springs, seats, and seals. Before the chemical energy of the gasoline can enter the combustion chamber, it mixes with air to form an air fuel mixture, which then is sucked through a vacuum into the cylinder before it combusts to form the rotating assembly’s rotational energy. To control the air fuel mixture’s entrance into the cylinder, a camshaft is used to trigger the opening of an intake valve. The camshafts operate by chain from the rotational energy of the crankshaft as referenced in Figure 2. While energy flows through all of the subsystems of an engine, there are many output energies that are byproducts of the intended use, to create rotational energy. A main byproduct of an engine's energy flow is the heat produced by the Otto Cycle. This heat energy takes a few forms, including the heat energy of the exhaust gases exiting the cylinder after combustion, and the heat energy of the cylinder after combustion. With heat energy being such a large byproduct of an engine's entire process, there are multiple subsystems associated with the dissipation of this unwanted heat. The heat energy produced is dissipated through the cooling subsystem which includes the coolant, oil, water pump, oil pump, coolant passages, oil passages and radiator. Heat energy is transferred to the coolant via the water passages in the engine block. The coolant is then cycled through to the radiator by flow energy of the water pump, and the heat energy is then transferred to the outside air via a radiator. The heat energy is transferred by the oil in the same manner.
A majority of this engine is made out of cast iron. This includes the block and cylinder heads which are visible from the outside. The intake manifold is made of cast aluminum and composite metal. The internal parts that are not currently visible include the crankshaft, which is also cast iron, and the connecting rods are made of powder metal. Cast iron is a heavy material which is a drawback when considering the rotational mass, but it is quite durable. This will allow the engine to run for a long period of time, assuming it is maintained well.
User Interaction Profile
The user of the Vortec 4300, could also be referred to as a consumer who purchased a vehicle containing the engine, interacts with the engine in a few unique ways. The first would be in the actual use of the vehicle for transportation. The engine is used for the rotational energy it produces which is converted to translations energy by the car's other systems. Therefore the user is interacting with the engine through starting cycles, throttle inputs, dashboard gauges and other translational aspects. The user also experiences other operational effects of the engines such as noise, exhaust gases, and heat. The product is relatively easy to use in a automobile, not having any other inputs besides throttle and only consuming oil and fuel. This makes operation easy for the average consumer. Regular maintenance consists of changing the oil, changing spark plugs, changing the air, oil and fuel filters. Being fuel injected, there are no carburetors to maintain which makes the Vortec much more user-friendly than other engines. Most of these jobs are able to be done by the average consumer with a small amount of written assistance.
Product Alternative Profile
The engine was originally introduced in 1985 in the Chevy Astro van and C/K pickup trucks. In the Astro, it was a larger alternative to a 2.5 Liter inline four cylinder. In the pickup, it was the smallest engine available with options being a 5.0L, 5.7L, and 7.4L gasoline engines. In each application, it offers different advantages and disadvantages. In the Astro van, as the larger alternative, it was less fuel efficient, thus more expensive to run. As an additional optional, it cost more to purchase a van with the Vortec 4300 as opposed to the inline four. Since it was a larger engine, it did produce more power, which may have been a necessity for some. On the other hand, Chevrolet did not offer a smaller engine in the C/K pickup. The Vortec 4300 was the base model engine, which means the customer did not have to pay to have this engine as an option. It provided better fuel efficiency than the other engine options, but the smaller displacement resulted in the least amount of power offered for the C/K trucks. This may have been optimal for those who did not need to haul or tow anything, but others may have needed more power for their intended use. The consumer would have to evaluate their needs and decided if the Vortec 4300 would fit their demands.