CAPSTONE DESIGN COURSE
MIM 1501-1502
Techanical Design Report
Development of an Automotive OH Filter Project# W98/S98-3
Final Report
Design Advisor: Prof.Yiannis A. Levendis
Design Team Christopher S. George, Babajide Odunayo, Gary Ng, Tommy Tran, Andrew T. Veneziano
June 1, 1998
Dept. of Mechanical Industrial and Manufacturing Engineering College of Engineering, Northeastern University Boston, MA 02115 Memo
Date: 6/1/98 To: Prof. Levendis, Prof. From: Oil Filter Design Team RE: Submission of Quarter
We would like to thank Prof. Yiannis Levendis, Ms. Deanne Harper, and Prof. Achille Messac for all their hard work and guidance that they have given our design team.
Please note several sections when reading this report. The first nineteen pages of the report are associated with the problem statement, financial analysis, patent and literature search, a.11d initial design concepts. Please also note the middle section of the report containing the torque, force and velocity calculations using centrifugal force. The last section of the report shows the highlights of designing the prototype and the test apparatus. The last section also has the most important part to the report, the conclusion.
During the process of designing the prototype, the team had several challenging design problems. First was the inefficient financial status, second was the lack of time for the machinist to machine parts needed to finish the prototype. Having these difficulties, the actual time of developing and designing will be longer than what has been anticipated.
Keeping this in mind, please read the enclosed report. We look forward to your comments and suggestions. Please feel free to direct this report to any of your colleagues that might be interested in it.
Once again thank you for your time and effort in this design project.
6/1/98 Confidential Table of Contents
Table of Contents ...... 1-v
1) Abstract ...... 1
2) Initial Problem Statement and Background Information ...... 2
3) Financial Analysis of the Mechanical Oil Filter ...... 4
4) Patent Search ...... 7
4.1) Introduction to Patent Search ...... 7
4.2) Patent#4,557,8 31 Inventor : Fredrick Lindsay ...... 7
4.3) Patent#5,203,999 Inventor : Michel G. Hugues ...... 8
4.4) Patent#4 ,871,458 #5,096,581 Inventor : Ronald J. Purvey ...... 8 & 4.5) Patent#4,253,953 Inventor : Zoltan L. Libertini ...... 9
4.6) Patent#4 ,492,631 Inventor : Martin H. Woods ...... 9
4.7) Conclusion of Patent Search ...... 12
5) Literature Search ...... 13
5.1) Initial Results of Literature Search ...... 13
5.2) Textbook ...... 13
5.3) Technical Papers ...... 13
5.4) Other Forms ofinformation ...... 14
5.5) Conclusion to Literature Search ...... 14
6) Initial Centrifugal Oil Filter Design Concepts ...... 16
6.1) Introduction oflnitial Design Concepts ...... 16
6.2) Initial Design#1 :Stamped Rotor Design ...... 16
6.3) Initial Design #2 : "Cheese Grater" Design ...... 17
6.4) Initial Design #3 : Impeller Design ...... 18
6.5) Conclusion and Choice of Initial Design Concept ...... 19
7) Initial Testing ofSAE lOW-30 Oil in a Centrifuge ...... 20
7.1) Introduction ...... 20
7.2) Initial Testing to Verify if a Centrifuge Could Clean Dirty Oil ...... 20
7.3) Initial Testing to Verify Angular Velocity (w) of the Centrifuge ...... 21
7.4) Conclusion and Future Testing ...... 22 Table of Contents
8) Centrifugal Force and RPM Calculation ...... 23
8.1) Introduction ...... 23
8.2) Determine of Laminar or Turbulent Flow ...... 23
8.3) Force and RPM Calculations ...... 23
8. 4) Conclusion ...... 27
9) Torque Calculations ...... 28
9.1) Introduction to Torque Calculations ...... 28
9.2) Torque Calculations ...... 28
9. 3) Conclusion ...... 30
1 0) Centrifugal Oil Filter Prototype Design ...... 32
0.1) Introduction to the Centrifugal Oil Filter Prototype ...... 32 1
1 0. 2) Design and Construction of Centrifugal Oil Filter Prototype ...... 32
10.3) Conclusion oflnitial Centrifugal Oil Filter Build ...... 33
11) Ceramic Oil Filter Prototype ...... 34
11.1) Introduction to the Development of a Ceramic Oil Filter ...... 34
11.2) Whywould you use a Ceramic Monolith? ...... 34
11.3) Description of Ceramic Monolith ...... 35
11.4) Description of Ceramic Monolith Holder ...... 35
11.5) Conclusion of the ceramic Oil Filter Design Section ...... 36
12) Testing Apparatus ...... 37
12.1) Introduction to the Development of the Oil Filter Test Fixture ...... 37
12.2) Development of an Oil Filter Testing Apparatus ...... 37
ii of Contents
13) Work Completed as of Report ...... 40
A. Mission Statement ...... 40
B. Financial Analysis ...... 40
C. Patent and Literature Search ...... 40
D. Initial Ideals ...... 40
E. Mathematical Verification of Centrifugal Idea ...... 41
F. Torque Calculations ...... 41
G. Centrifugal Oil Filter Prototype ...... 41
Ceramic Oil Filter Prototype ...... 41
I. Test Apparatus ...... 41
14) Work that Needs to be Completed ...... 42
15) Conclusion ...... 43
iii Table of Contents
Figures and Tables
Figure 2.1: Cost of Recycling Operations ...... 2
Figure 3.1: Cost Comparison of Conventional and New Mechanical Filter ...... 5
Figure 3.2: Decrease in Sales Price as a Function of Total Yearly Sales ...... 5
Figure 4. 1: Glacier Spinner II Unit ...... 10
Figure 4.2: Glacier GF 600 with Lever Control Base (LCB) ...... 11
Figure 4. 3: Engine Schematic (Glacier Parallel W/ Conventional Filter) . . . . . 11
Figure 6.1: Initial Design Matrix ...... 19
Figure 7. 1 Initial Centrifugal Variac Testing ...... 21 :
Figure 8.1: Laminar Flow Determination Chart ...... 23
Figure 8.2: Radial Velocity as a function of Dia_,oarticle and RPM ...... 25
Figure 8. 3: The Minimum Particle Dia. That will hit the Centrifuge Wall ..... 26
Figure 8.4: Oil Flow in Glacier Oil Filter ...... 27
Figure 9. 1: Torque vs. Temperature @2000,3 000,4000 RPM ...... 30
Figure 9.2: Power vs. Temperature @2000,3 000,4000 RPM ...... 30
Figure 10. 1: Prototype Filter Attached to Variac (Black Fluid) ...... 32
Figure 10.2: Prototype Top ...... 32
Figure 11.1: Panasonic FT 1168 Ceramic Monolith ...... 35
Figure 12.1: Testing Apparatus ...... 37
Figure 12.2: Pump and Pump Housing ...... 37
Figure 12.3: Mixing Chamber ...... 38
Figure 12.4: A Conventional Pram Oil Filter Pressure Gauge ...... 39 &
Figure 12.5: Efficiency Test Apparatus ...... 39
Figure 12.6: Light Source and Photocell ...... 39
IV Table Contents
Appendices
A. Financial Analysis of Oil Filter ...... A-1
B. Initial Oil Filter Designs ...... B-1
Angled Rotor Design ...... B-2
"Cheese Grater" Design ...... B-3
Impeller Design ·································································· B-4
Ceramic Filter ...... B-5
C. Patents and Literature ...... C-1
1. 4557831 Centrifugal Filter Assembly
2. 4871458 Centrifugal Filter
3. 4253953 Centrifugal Oil Filter
4. 5203999 Centrifugal Oil Filter W/ Particle Collection
5. 5096581 Centrifugal Oil Filter
6. 4492631 Centrifugal Separator
D. Centrifugal Force Calculation Data Tables Graphs ...... D=l &
E. Torque Calculation Graphs ...... E-1 & F. Gantt Chart House Quality ...... F-1 & G. Centrifugal Performance Variac Calculation test Results ...... G-1 &
v 1.) Abstract
The purpose of this report is to describe in detail the design of environmentally an friendly oil filter that is highly efficient and cost effective. It also defines what an environmentally friendly oil fi?9hy the conventional oil filter (ex: Fram®) is not an environmentally friendly oil filter. The problem statement put before our design team is clearly defined within the report as well as the individual parts of the problem statement.
Our design team has chosen to use the principle of centrifugal force in our oil filter design. As an alternative we will also pursue the use of a ceramic monolith as our filtering medium. The report will discuss in detail the mathematical limitations and principles of centrifugal forces. Existing oil tilters are bad for the environment and there are several reasons why. This report is intended to be an in-depth look at why the present day oil filter is bad for the environment and what are the factors that make up the design of a new and efficient environmentally oil filter. 2.) Initial Problem Statement and Back�:round Information
In 1996 there were 420,000,000 automobile oil filters sold in the United States [ 1]. Of those, 331 ,800,000 were used and then disposed of in a landfill.The EPA has deemed oil filter waste as toxic [ 1]. Consequently, this waste is an enormous environmental problem. The design problem placed before our team was quite simple, to design an automobile oil filter that is not only environmentally friendly, but also a high quality and cost effective oil filter. Presently 21% of the oil filters used in the United States are recycled. The oil filters are recycled in several different ways. The first and most widely used process is to simply crush the oil filters into small cubes. This method however has one large problem associated with it. During the crushing procedure, several mills around the United States have experienced fires. The residual oil left over in the oil filters is the cause of the fires. To eliminate this risk several other recycling companies have looked at different means to safeiy recycle oil filters. One method that was developed by Oil Wringers Inc. in Farmington, Minnesota is a process where the oil filter's top is removed, and the paper element is allowed to fall out [1]. Another method that was developed is to shred the oil filter casing and then separate the different Fmancia11 Analys1s of Oil1 Filter �- ITotal# of liters sold m - ---J parts. Other recyclers use a means of � 4 0,000,000 96 : -I _ 2 _ ost or a Fram 1 Filter: _ crushing that differs from the method $ _ 3.99 ::f1ts mosf\T-81i;merlcanEngmes 1 _ -- - - 1--- - -r --1------jl------1i mentioned ab stead they use ultra rcrtarspenco-ri-Oi1Tflferslnl996 ---- � @ r-· ir-T.67o-;soo,ooo high pressure to seal off the crushed oil IAssumptlon! s m Recyc mg I ------1 ------_ l - filters. Recycling, while sounding like a ; Used OlrFllteri31n 1.) iurums to get 1 tOn55 of 9ararum---;--steel : 26016 1I2-J good idea, is unfortunately not profitable for many companies. Across the United
States in 1996, the amount of money made Figure Cost ofRecycling Operations 2.1: industry wide only amounted to approximately 10 million dollars. Figure 2.1 shows a simple spreadsheet that predicts an estimation ofthe total amount of money made by oil filter recyclers 1996 (See Fig 2.1 or Appendix A.).
2 The only solution to decreasing the contamination of the environment from used oil filters is to eliminate the problem entirely. To eliminate the problem entirely, a new oil filter must be designed that is fr iendly to the environment. What is an environmentally friendly automobile oil filter? To answer this question, you firstmust determine why a used oil filter is considered by the EPA to be toxic waste. We found that due to the presence�sidual oil that remains trapped in the /JL , paper element, the oil filter is considered hazardous waste, even after proper drainage.t1/"' We then discussed and looked at several ideas as to how we could better remove the oil from the used oil filters. For an oil filterto be safer fo r the environment the team determined that we would either have to settle for a two part oil filter design, where the paper element would simply be discarded and the metal cap would be continually reused. Or a permanent mechanical oil filter would need to be developed that would separate the waste particles fromthe oil. The team decided on the latter as our primary choice. The mechanical principle of centrifugal fo rce will act as our filtering medium. Although more complex and significantly more expensive, we decided to pursue the idea of a mechanical oil filter since we could all but eliminate the harm caused to the environment by landfilling used oil filters. By utilizing a mechanical oil filter, the only waste that will be generated will be the particles that are separated from the oil. A mechanical oil filter will remain with the car over the car's life. As a back up to the mechanical oil filter,a two part oil filter will be designed that will utilize a ceramic monolith as its means of filtering. As with any new design once you understand the problem statement, you must first conduct a market survey and a background search of patents and literature to verify that there is in fact a market. You must verify that someone will buy your product for, in this case, what will ultimately be a more expensive oil filter. Once that is completed you can begin to create some initial designs that will either verify or negate what you initially saw as a solution to the design problem. Finally you must redesign and retest your prototypes, and make any future recommendations that need to be made. This report will describe those ver; things yet in greater detail as they pertain to the design of an environmentally friendlyoii filter.
3 3.) Financial Analysis of the Mechanical Oil Filter and Ceramic Oil Filter Designs
Having stated that the design would be mechanical in nature, and therefore much more complex than existing designs, the team had to determine whetherit was financially feasible to design and build a mechanical oil filter. To verify whether there would be a market for a more expensive yet permanent oil filter, and to get some understanding for what the target price would have to be, the team needed to speak with someone in the automotive industry. We spoke with Mr. Philip HarperJr. who is the owner and operator of Lumber St. Auto in Hopkinton, Massachusetts. Lumber St. Auto does approximately
20 oii changes a day, or over 5000 a year. According to Mr. Harper the average car owner is very interested in Lumber St. Auto's operations and how they affect the environment [2]. A permanent oil filter, Mr. Harper feels, could possible sell for between $50 and $100, since it would be permanent and environmentally friendly. In his opinion people are more likely to pay more for something if it will keep their car out of the shop for a longer period of time. An average car oil filter costs anywhere from $4 to $8. If the car owner has his/her oil changed every 3,000 miles, drives 15,000 miles a year, and owns the car for 8 years, the car owner will spend approximately $160 to $320 over the life of the car for oil filters. This is a substantial amount of money for such a small device. To counter this high cost the team looked at manufacturing, supplier, and material issues, and determined the target market price was $100. (See Figure 3.1) Figure 3.1 shows the significant amount of money a car owner would spend over the life of his/her vehicle on conventional oil filters. Figure 3.1 also shows the savings to the car owner if he/she utilizes our oil filter.
4 Cost Comparison of Existing Design to Mechanical Design Present Oil FifteTi 1 m $160.00 Design (yearly cost) I $140.00 PresentOil Fifter $120.00 ll!llDesign (Life of the I $100.00 i car cost $80.00 i 1ii0 Mechanical Oil Filter I 0 $60.00 I 0 Design (initial cost) $40.00 $20.00 .....,.,.,.,.,Oil " 1 .. Design (life of the"' $- 1 car cost) I j ....-1 Figure Cost Comparison of Conventional Filter to Mechanical Filter 3.1: Oil New
While the price of the mechanical oil filter is it will save the car owner over 50% on the amount of money he/she pays for conventional oil filters over iife of the car. Also as more more units are sold, the cost of supplies and manufacturing will significantly decrease, thereby price of the oil filter. future sales price of $90 is possible after 10,000 units are made, and then the filter would further decrease cost to $75 after 100,000 units are sold. After 1,000,000 units are sold annually the sales price would drop to $50 (See Figure 3.2).
Decrease in Sales Cost
,...... =:------., $100.00
$80.00
$60.00
$40.00
$20.00
$- 1000 10000 100000 1000000
Total Annual Production Units
Figure Decrease SalesPrice as a Function of Total YearlySales 3.2: in
5 4.) Patent Search
4.1: Introduction to Patent Search
Before we could begin to design the centrifugal oil filter, the team looked at what was already out on the market and/or patented. The team conducted a prior art search that concentrated on centrifugal oil filter design. It is crucial when any new product is designed that the design team first determines whathas already been designed so that they can save time in the overall design process. Too often engineers are so eager to begin the design phase that they start the product design before they have an understanding of what has already been designed. Our goal is to design an oil filter that is cost effective and safe for the environment. Time spent early on the patent search will allow us to design an original centrifugal oil filter in the shortest period of time and at the lowest cost to the customer. Upon conducting the initial patent and literature search, the team discovered that there has already been some work done on centrifugal oil filters. The idea of using the principles of centrifugal force to separate the waste particles from the oil stream is not a new idea. While not a new idea, the number of centrifugal oil filters are few. The team discovered a total of six patents concerning theirdesign.
4.2: Patent #4,557,831 Inventor : Fredrick Lindsay
The first patent for an oil filter that utilized the principle of centrifugal forces was a design that was invented by Frederick Lindsay. Mr. Lindsay's patent, #4,557,831, is for a centrifugaloil filter that utilizes a disposable rotor mounted on a reusable shaft. The filter is then fixed to an adapter on the engine block. His design utilizes a replaceable gasket to seal the oil filter. Fredrick Lindsay's design is a self-powered oil filterthat relies upon the pressure of the oil flow to induce the rotational motion of the oil filter. Mr. Lindsay's design is currently being used on Mack Trucks on all of their heavy rigs (See Appendix B Patent #4,557,831). There are several aspects of Mr. Lindsay's design that we hope to improve upon our design. The first is the attachment method to the engine block. In our design we intend to use the same attaching method as a present car. There are two reasons for this.
7 The first reason is that it costs significantly less to attach the oil filter directly to the engine, as opposed to designing an adapter for the oil filter. If we were to design and build an adapter, the time spent on the design and the adapter itself, would raise the cost of our filter. Second we want to keep the design as simple as possible for the car mechanic. Another aspect ofMr. Lindsay's design that we want to improve upon is the replaceable gasket. Every gasket that is thrown out hurts the environment. Our design will consist of only reusable gaskets.
4.3: Patent #S,20�.999 Inventor : Michel Hugues G.
The second patent, #5,203,999, concernsMichel G. Hugue's centrifugal oil filter design. Mr. Hugue's oil filter design centers around a bowl that rotates around the vertical axis of the oil filter. A groove within the spinning center bowl captures the waste particles of the oil as the oil flowsover the top of the bowl and is returnedto the engine through a hole in the bottom of the oil filter. Mr. Hugue' s oil filteris a good design. It is cost effective and simple. His use of a bowl, or rotor, as the containment method for the waste particles is effective. The biggest problem though with his design is the way in which it would be attached to the car's engine block. His design shows that the car's dirty oil stream would enter the oil filter in the top center. Given that we intend to use the present attachment method, his idea would not work. On any given car manufactured in the last 30 years, the oil enters from the circumference of the top and exits through the center. To utilize Mr. Hugue's idea would entail designing an adapter piece that would raise the cost and complexity of the oil filter.
4.4: Patent #4,871,458 and #5,096,581 Inventor : Ronald Purvev J.
The third and fourth patents concern centrifugal oil filters designed by Ronald J. Purvey. The first patent, #4,871 ,458, describes a centrifugal oil filter that uses an oil flow jet design as the means of propulsion for the rotor assembly, which acts to collect the waste particles fromthe oil. The second patent, #5,096,581, uses a disposable rotor cartridge as the means fo r removal of the waste particles. While both of these patents offer a solution to the problem, neither of them solves our design problem. The first design makes assumptions about the entrance ofthe
8 flow. The oil flow can not enter fr om the center. The second design uses a throwaway rotor. Both designs are good, but they do not meet our design specification that states that we will design an oil filter that will clean the oil while not requiring any part of it to be replaced on a regular basis. Mr. Purvey's second idea is better than what is out on the market. However the detrimental effect of the disposable rotor on the environment makes the design undesirable.
4.5: Patent #4,253,953 Inventor : Zoltan L. Libertini
The fifthdesign that was patented, #4,253,953, was a design by Zoltan Libertini. Mr. Libertini' s design utilizes an oil pump and an irregularly shaped rotor. The oil is pumped into the rotor, whereby the pressure induces a rotational motion of the irregular shaped rotor. The irregularity in the rotor then traps the particles of waste, while at the same time allowing the oil to pass out the other end of the oil filter. Mr. Libertini' s idea, while ingenious, is complex. The complexity of this design would make it difficult and expensive to manufacture. For a centrifugal oil filter to be practical it must have a simple design, be relatively cheap, and not difficultto manufacture. Mr. Libertini' s centrifugal oil filterdesign is none of these. Unfortunately this design will not help our design team out. Zoltan Libertini' s idea, while a good one, is a case of a good design that cannot be financialiy justified fo r manufacture.
4.6: Patent #4. 492,631 Inventor : Martin H. Woods
The sixth and final patent, #4,492,631, is the most complex. Martin H. Wood's centrifugal oil filter design uses the pressure of the oil to generate the rotational motion of the rotor assembly. Wnat makes it so complex, however, is the use of a sump in the bottom of the filter assembly. The sump is used in conjunction with a float-operated valve, to maintain the air/oil mixture within the rotor. Figure 4.1 and 4.2 are two pictures of Mr. Wood's design. The oil filter line is built by Glacier Metal Inc. in Somerset, England. Figure 4.1 clearly shows the oil sump located in the bottom of the oil filter.
9 The sump is used to control the amount of oil/air mixture that is in the rotor. As more oil enters the rotor the sump allows more air to enter the rotor. If this mixture is not precisely controlled, the oil filterwill either not work efficientlyor it will cause a back pressure in the oil flow that will decrease the power and efficiency of the automobile/truck engine. Figure 4. 1 also shows the cross section of the rotor. It should be noted here that the oil enters the rotor from the center of the rotor. Figure 4.2 is another example of a centrifugal oil filterthat Glacier Metal Incorporated sells. Figure Glacier @Spinner Unit 4.1: II Figure 4.2 dearly shows the rotor ht1p:iiourworld.compuserve.comthomepages/ glacier_filters/glacie r.htm assembly. Mr. Wood's design is the most complex of all the centrifugal oil filters. The oil filter attachment method of Wood's Mr. design is the same as a modern car oil filter. His design validates the fact that it is possible to attach a centrifugal oii filter to a car without the need for an adapter. Furthermore he has demonstrated that the proper design can in fact be manufactured and sold for a profit. must be noted that although Wood's design filters the oil, it must work in It Mr. parallel with a conventional filter [3]. Glacier's product is a bypass filter. was designed It to work on diesel engines where it can remove the soot particles are less than 111m in diameter.
10 Figure Engine Schematic of Glacier Filter Parallel a 4.3: in with
Conventional Filter Figure Glacier@ GF with Lever 4.2: 600
"A Method for Meaningfully Evaluating the Performance of Control Base(LCB) Source: a By-Pass CentrifugalOil Cleaner", Andrew Samways and Ian M. L. Source: Cox, SAE Tech Paper http://ou.•"'Horld.compuserve.com/homepages/ 980872 glacier_ftlters/glacier.htm
Figure 4.3 shows the Glacier Filter in parallel with a conventional oil filter. is our It desire as a design team to eliminate the full flowoil filterpic tured in Figure 4.3, by designing and constructing a fullflow cent rifugal oil filter.
11 4. 7: Conclusion o(Patent Search
Our design team has looked at several patents. We have looked at where the designs are strong and where they are weak. The patent search has indirectly highlighted why all but two of the above mentioned centrifugal oil filters have not made it to market. All of thedesigns are too complex and therefore will cost too much to manufacture. It is nice to care about the health of the environment, but when businesses look at these centrifugal oil filter designs they see products that are too expensive to manufacture. The previous oil filter designs have priced themselves right out of the market. The patent search has shown our team that for our centrifugal oil filterdesign to be a viable option on the market, the design must be simple and cost effective.
12 5.) Literature Search
5.1: Initial Results ofLiterature Search
Once the team had conducted its patent search, we proceeded to do some research on centrifuges and the principle by which they work. The amount ofliterature that the team discovered was small. The only book that the team discovered was entitled, Centrifugal and Axial Flow Pumps (Theory,Desig n, and Application), by Alexey J. Stepanoff. In his book, Mr. Stepanoff discusses the principles of pumping fluid by a centrifuge, but he does not go into great detail about the dynamics ofthe fluid in the centrifuge. Fluid flow within a centrifuge is an extremely complex problem since the fluid flow is most likely turbulent and in three directions. Alexey J. Stepanoffs book was of no real aid to the design team.
5.2: Textbooks
The team then concentrated its literature search on textbooks and other technical writings about the fluid dynamics of a rotating body of fluid. The most useful piece of literature we fo und was a book written by James P. Vanyo, Rotating Fluids in Engineering and Science. In it, the team fo und many useful pieces of information, such as the efficiency of a centrifuge.
effeciency(s) � (�m)(rcv)4L (Eq. 1)
The team also discovered two books on simple fluidmechani cs, Introduction to Fluid Mechanics (3rd Ed.), by James E. John and William L. Haberman, and Mechanics of Fluids, by Merle C. Potter and David C. Wiggert. In both of these books the authors give general examples of fluid flow in rotating bodies. These books gave the team a start on understanding the complexity of the fluid flowin a centrifuge.
5. 3: Technical Papers
The team also discovered two SAE papers of value to our design. first paper, SAE paper #980872, entitled, "A Method fo r Meaningfully Evaluating the Performance
13 of a By-Pass Centrifugal Oil Cleaner," by Andrew Samways and Ian M. Cox. This paper was helpful in that it educated the team on how Glacier tests the efficiency of their oil filters. Unfortunately in the paper they did not describe any great detail their design. It is also important to note here, as mentioned in the Patent Search section of this report, that Glacier's centrifugal filter is used in parallel with a conventional filter. It was designed to remove the finewaste particles (Diameter 5.4: Other Forms o(ln(ormation Other than textbooks and technical papers highlighting rotational fluid dynamics and centrifugal forces, the most useful piece ofliterature was Glacier Metals Inc's web page, 'http://ourworl d.compuserve.com/homepages/glacier_ filters/glacier.htm'. On this web page we discovered numerous schematics that were helpful in understanding how the Glacier oil filters work. 5.5: Conclusion to Literature Section Although the team was able to find several pieces of technical literature on the subj ect of centrifuges and fluid dynamics, we were not successful in finding literature pertaining to the specific nature of our design problem. The nature of our design problem could best be termed, "Time Dependant Centrifugal Fluid Dynamics." Most literature on centrifuges assumes that the fluid in themis independent of time. When a test tube filled with dirty spms a centrifuge, the required to separate the waste particles from 14 the clean oil is independent of time. The centrifugal load is assumed to be a static load. In the case of our centrifugal oil filter design this is not the case. The oil will only spend approximately 2 to 3 seconds in the oil filterbef ore it exits the filter. Therefore we can not rely upon the calculations and equations in the literature we fo und to determine the required rpmwe need to separate the waste particles from the clean oil. The information that the team has taken from the textbooks and technical papers is meant as a starting point for further researchand experimental discovery. 15 6.) Initial Centrifugal Oil Filter Design Concepts 6.1: Introduction o(Initial Design Concepts An important part of any design process is the time that the team uses to brainstorm onthe design problem. Our design problem was clear; we were to design an oil filter that was reusable and safe fo r the environment. It became clear in the early stages of the design process that the team was going to pursue a centrifugal oil filter design. There are a couple of advantages to the centrifugal idea, one it is already a proven mechanical idea, and two it is reusable. The design problem then became how to design the oil filter at a low cost. The next step the team faced was to visualize and document any initial design ideas. The team came up with over ten designs, but for the purposes of this paper we have decided to limit the number of concepts to three. Each design will be discussed in greater length later in this section, but they can brieflybe described as a "cheese grater" design, an impeller design, and a simple rotor design. Unlike all of the previous centrifugal oil filters that have been designed, our design will rely upon a motor to drive the rotor or impeller. An electric drive motor was chosen as the means of propulsion fo r the simple reason that it is simple and effective. The previous centrifugal oil filters designs relied upon the car oil, under pressure, passing throughje ts machined into the rotor assembly to act as the means for generating the spin of the rotor. The jets are complex to machine, and therefore the oil filter would cost more. An external electric drive motor is a simple and effective way of driving the rotorlimpelier. 6.2: Initial Design #1: Stamped Rotor Design Our first design, (See Appendix C Page 1) is quite simple due to the few number of parts needed for the complete assembly of the oil filter. This design involves a stamped cup made out of aluminum that is driven by an electrical motor. The key to this idea is the shape at the bottom of the metal cup, or rotor. this design to work, the base must be angled up and inward, toward the center of the oil filter. rotor spins the centrifugal forces acting on waste particles will drive 16 them to the outside of the rotor. The pressure of the oil entering the filter will then push the waste particles to the base of the rotor where they will be collected in a narrow groove. The inward angle of the base will then act to direct the clean oil, which is less dense than the entering oil, towards the center of the oil filter. At the center of the filter the clean oil enters a tube and exits to the engine. This design has many advantages. • It would be quite simple to manufacture the rotor. The rotor could simply be stamped out of sheet metal. • It has a small number of parts. • The filter would be able to fiton any modem car without any adapters or fixtures. • The center of a centrifuge and of our oil filter is the place of lowest pressure. For that reason the clean and less dense oil would flowtoward the center of the oil filter and away fr om the heavier and denser waste particles. • Fifth,the automobile mechanic can easily unscrew the outer casing and clean out the oil filter. • Sixth, it uses an electric motor as its primary means of rotational motion, and therefore does not rely upon the complex jets of previous designs. There are, however, possible areas of concernwith this design. The firstconcern arises during the initial starting of the car: whether the initial force of the moving oil might cause some of the deposited waste particles to be agitated and pulled into the clean oil stream. The other area of concern is designing the angle of the base to allow the clean oil to move up and toward the center of the oil filterwhile keeping the waste particles at the bottom. 6.3: Initial Design #2: "Cheese Grater" Design The second design is comprised of multiple rotors inside one another. (See Appendix C Page 2.) Each rotor has over one hundred holes in it. Each subsequent rotor's holes decrease size as they approach the outermost rotor of the oil filter. This design also utilizes an electric motor as the primary means of rotational motion. Shown in the 17 hand-drawn sketch, the motor is connected to the rotors by a gear system. This was drawn to highlight the different ways that the motor could be affixedto the oil filter if a space constraint arose with a given car engine. Unlike our previous design, where everything stayed within the rotor, in this design the clean oil will be able to escape the rotors. The basic principle of this design is that the waste particles will be trapped in the rotors, and the holes will act as a means for the oil to escape to the area between the outer most rotor and the casing of the oil filter. Once the oil has traveled to this area it will be pushed to the bottom of the oil filter, where it will then move towards the center of the oil filter and returnto the engine. Unfortunately, this design does not have many advantages. Its advantages are: • It would be easy for a mechanic to clean this oil filter. • The multiple rotor design would likely remove more of the waste particles fromthe oil. However both of these would come at a price. The multiple rotor design is just too complex to manufacture. Keeping in mind our original problem statement that our costs must be kept to a minimum, this design is not viable unless the cost to manufacture it can be decreased. The multiple rotor design would also create turbulence in the oil flowthat would decrease the filter's efficiency. 6.4: Initial Design #3: ImpellerDesi gn The third design utilizes impellers to generate the centrifugal forces. (See Appendix C Page 3.) Four impellers driven by an electrical motor would generate the required centrifugal force needed to separate the waste particles from the oil stream. The impellers would induce a rotational flow in the oiL Consequently the forces acting on the rotational flowwould force the heavier waste particles to the outside of the oil filter, where they would affixthemselves on the wall of the filter. The number ofblades is unknown at this time, but could theoretically be 4, 6, or 8. The biggest advantage of this design is the cost to manufacture it. The impellers could be bought for �ss a piece and electric motor could be bought off the shelf for �$35. The only design issue would be the center tube and the oil filter casing. both of the 18 previous designs we would mount the oil filterto the car engine the exact same way that present oil filters are mounted. Even though production costs for the impeller design would be on the low side, due to the large number of "off the shelf' components, the concernis whether or not the design could produce he required centrifugal fo rce. Another area of concern is how to design the impeller-mounting scheme. The impellers must be mounted in such a way that they are held in place, but at the same time, the oil must be allowed to flow through the center of the impeller's rotation. Finally this design would create a significant amount of turbulence in the oil stream and thereby would decrease the filter's efficiency. 6.5: Conclusion and Choice o(Initial Design Concept After our initial brainstorming session the team took a look at the three designs mentioned above and compared them to an existing Fram® oil filter. The team determinedthat our first design choice was the angled rotor design. Below is the design matrix the team used to come to that conclusion. I� I (j) i I I c i E I I I 4-> (/) Q) ro Ol '--c ...... £ .s::E 0 0 t:: > .� · · 0 � ::J ro (.) c ;;: c: (.) 4-0... ro E ro c ::J. . ::i.. tE - Q) Q) UJ £ 0'- ..,__<( ...... n::: (3'+- 0 c .. 0 :0 ...... c Q) 0 0 0 (/) (/) (/) ..0 ro - Ol Cl)(/) Cl)(/) (/)Cl) t5 ....n; � � ·u; E ::J Design 0 0 Q) ::J ro ro ro � Q) 0 ()++ ()-- 0 z UJ UJ UJ-- -- UJ n:::-- 1- 1Ex1stmg Des1gn (Fram, 0 0 0 0 -6 Angled Kotor + - - + I u u u 2 - + - -- + + + "Cheese Grater 0 0 0 Impeller - + - + + + u u u 2 Fig Initial Design Matrix 6.1: By utilizing a design matrix to analyze the different design choices and their attributes separately, it became obvious to the team that the Angled Rotor Design and Impeller Design were the best choices for our design problem. Both the ease of cleaning and the cost to the car owner over the life of the vehicle are significantly better when compared to the conventional oil filter. After some discussion we chose the Angel Rotor Design as the design we would pursue as a team due to fact that it met our design 19 requirements and the oil flowwould be less turbulent through it, thereby creating a more efficient filter. -,_.- /,.) Initial Testing of SAE lOW-30 Oil in a Centrifuge 7. 1: Introduction In order to verify the idea that the principles of a centrifuge could be utilized to clean dirty oil, the team conducted testing of dirty oil samples spun in a conventional bench top centrifuge. The initial testing that the team did was very informative. Centrifugal force was found to be a viable means of separating the waste particles fr om dirty oil. Three test samples were spun in a centrifuge. The three samples were carbon black, coal slurry, and diesel soot mixed with automobile oil. The carbon black and coal slurrywere both obtained fromthe lab. Some oil used in the test contained diesel soot, which was obtained from the preliminary test of a ceramic oil filter. 7.2: Initial Testing to Verifyif a Centrifuge Could Clean DirtyOil The carbon black was manufactured by Cabot Corporation. Unfortunately the particle size the carbon black could not be detennined. The test sample consisted of for 6.6 grams ofSAE lOW-30 motor oil with 0.12 grams carbon black added to it. Although it initially looked like the carbon black dissolved in the oil, this was not the case. The particles are so small that to the observer they seem to dissolve in the oil while the oil becomes black. The firsttest that we conducted, the centrifuge was spun to 3380 rpms for five minutes. There was no change at all in the appearance of the oil. We then allowed it to spin for 30 minutes. There was a substantial change in the clarity of the oil. The particles had separated from the oil and collected at the bottom of the test-tube. We did the same test with the coal slurrytest sample. The centrifuge was again spun to 3380 rpms for 5 minutes. The oil's appearance did not change at all. We tested it again fo r 30 minutes, and it did separate the particles. We also ran some coal slurry fo r 40 minutes and the resulting cleanliness of the oil was even better. The oil had almost turnedba ck to its original golden color. The size range of coal slurry particles is 3-5 microns. Unfortunately the cool slurry clumps together and is therefore hard to accurately determine the particle size from 20 the centrifuge testing. To combat the clumping of the cool slurry we placed the bottle containing the coal slurry in a mixer. This seemed to help break up some of the clumps. 7.3: Initial Testing to verifYAn gular Velocity(OJ) o(the Centrifuge To gain a better understanding of the importance of the rpm onthe ability of the centrifugeto remove the waste particles fr om the oil, we set a Variac series with our test centrifuge. A Variac was used because of its ability to decrease the number ofVolts supplied to the centrifuge motor, and thereby slow down the centrifuge. The team used a stroboscope to measure the rpmof the centrifuge. The rpm of the rotor was measured by placing a black line on the center of the inner rotor. Through a hole in the center of the centrifuge's cover, the strobe's light is allowed to pass and the rpm of the centrifuge can be accurately measured by adjusting the strobotachometer until the rotor seems to stop. The fr equency of the light flashesthat the strobotachometer displays is then equal to the rpm of the rotor. The Variac was set at various settings as we adjusted the stroboscope to determine the 1pm ofthe rotor. \Ve recorded the settings ofthe Variac and each ofthe associated rpm of the rotor. Figure 7.1 shows the various settings and rpms. 110 3300 100 3220 96 3180 90 3120 86 2800 80 2730 2080 1580 Figure Initial Variac Testing 7.1: 21 With this information we can set the centrifuge to any desired rpm. This will be helpful later when we wish to confirm theoretical calculations. We then used a digital voltmeter to measure the output voltage of the Variac at different settings. The team determined the function of the output voltage to the Variac setting. That will allow us to set the Variac at a specific setting and be able to findthe output voltage. With the output voltage and the current draw of the centrifuge,we will be able to calculate the amount of power used to spin the centrifuge. Output voltage as a function ofVariac setting is: Voltage = l.063*(Variac_setting) + 1.680 (Eq. 2) The initial testing verifiedthat a centrifuge is a viable option to clean automobile oil. Upon completion of the test apparatus, which will allow us to simulate a car engine by pumping dirty oil through the filter, testing will start with at least two conventional oil filters. The testing will fo llow the new SAE 11858 test procedure. The SAE 11858 test procedure offers more information than the previous SAE testing procedure, 1806, on what particle sizes pass though the filter. The new procedure takes into consideration the fact that modem cars have different materials in the engines, and are constructed differently than the older automobile engines were. SAE is in the process of sending the team a copy of 11858. 22 8.} Centrif11gal Force and RPM Calculations 8.1: Introduction As a waste particle gets larger and larger in diameter, it requires more and more force to push it through a viscous medium. In the case of our design problem, the viscous medium is lOW-30 automobile oil. The purposeof this section is to firstdetermine if the oil entering the filter from the pump of the car is turbulent or laminar. Once that is determinedthe required rpmand resulting centrifugal force can be calculated over a range of waste particle diameters. 8.2: Determination of Laminar or Turbulent Flow Before any calculations could begin the Oil Flow in Filter�> LAMINAR (Re<2000) team needed to determine if the oil flow within 1800 i the centrifugal filterwas Laminar/Turbulent. 1600 + 1400 1 The team determined that the oil flow was 1200 l! 1000 laminar. To do this the team relied upon 800 1 600 -.t equation 3 listed below: I I -�� ...... •uuaas•••••uuae 200400�.. ••••ssosuueuoou;a 1 1� Q � -! --l-1-L+-+-'--H---H+-++ 1---•-H-+·• -1---1---H I +++-H-;---1 +-t-t-+-t-h-++-f-<-+-H � � � m m � � ffi � � � � 2 � � � � * I (pVD) 0 0 Re = ' (Eq. 3) [4] � � � � � � � Radius � � (m) � � � � � � � Jl Figure Laminar flow determination chart The Reynolds Number is dependent on 4 8.1: variables. The first is the fluid's density (p), second, the fluid's Velocity (V), third, the diameter (D) or length (l) of the volume in which the fluid is moving, and fo urth, the dynamic viscosity of the fluid Figure 8.1 highlights the fact that a radius of 1 em (JL). from the center of rotation that the Reynolds Number is only 189.2. For a fluid to be considered turbulent the Reynolds Number must be over two thousand. The flow inside our oil filter can be considered laminar for all future calculations. 8.3: Force and RPM Calculations: oil filter medium fr om a Fram® filter, PH8A, was removed. It was then measured. The outer diameter, the diameter of the return port and length were 23 measured. The lengths were 9.4cm, 9.4cm, 1.7cm, respectively. Those measurements will be used throughout the theoretical calculations. Starting with the centrifugal force: (Eq. 4) [5] which is derived from Newton's 2nd Law of motion, Force equals mass times acceleration. Using the drag force equation fromStokes law, we found the radial velocity: (Eq. 5) [5] v = r 3 'lin� 1CfU-/ Particle Then we substituted the centrifugal fo rce equation (Eq. 4) into equation 5 and came up with the equation for radial velocity related to centrifugal fo rce: (Eq. 6) We then calculated the mass of the particle considering the buoyancy effect: (Eq. 7) Plugging equation 7 into equation 6 with V0 =(2m)ro, we get: V pPD;v� pPD;(21er(RPS))2 (Eq. 8) r = l8,ur 18,ur 24 A graph of the Radial Velocity (Vr) as a function of the Diameter of the Particle and the rpm of the centrifuge is shown below: Figure Radial velocity as a fu nction ofDia _parlicle and RPM 8.2: Figure 8.2 shows that as the waste particlesize is increased, the rpm must be increased in order to assure that the particle hits the wall of the oil filter. Any point that lies above the green surface in figure 8.2 would hit the wall of the oil filter. VI e calculated transverse velocity, Vt, by the flow rate of the 25 divided it by the area, 3.85 cm2• The flow rate is related to the displacement of the engine and the rpm: Q = 0.003(/iters)rpm (Eq. 9) [6] The area we used in equation 9 is the area of the annular space: (Eq. 10) [6] The resultant velocity is V, and it c�'lbe used to find the time at which a particle will transverse the length of the filter. The time needed for a waste particle to travel transversely is equal to equation 11: Length of oil filter t = ___;c _ _;;_ _ __;c __ (Eq. 11) [6] v We used time, t, to find the --;rm-1-les�-�::-te -Pa -rti-cle-t�at will hit thew all of the Oil filter the given @ horizontal distance that the �--- Dynanic Viscosity = kg/rn"3 RA\11: 0.0067 @ 120C particle vv ill travel, thus , '2 0 : determining wherever the 2 I 2.: ·.f D..� particle will hit the wall. We took "' 2iI � + the radial velocity, Vr, and "' 1.51 :5:1 "' + multiplied it by the time it takes i5 I 05 0 0 0 0 0 0 0 0 0 0. 0t 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 to transverse the oil filter. Figure N <:') LO <0 I'- 00 m ;: "'" 8.3 is a graph of the smallest RPM waste particle that will hit the Figure Th e Minimum Particie Dia. that will hit the wail of the 8.3: wall of the centrifuge at a given Centrifuge rpm. As the particle moves fromthe wall to the outer wall the radius increases, this causes Vr to increase. increasing Vr must be taken into consideration since the 26 particle will travel further along the horizontal axis, thus it will be closer to the outer wall than what was calculated. Given our method's lack of exactness, our method is an overall estimation of the rpm that the centrifugal oil filter will have to spm. The flow within a centrifugal oil filter is complex. Figure 8.4 shows a CFD (Computational Fluid Dynamics) model that was created to model a Glacier Figure Oil Flow in Glacier Oil Filter 8.4: Centrifugal Filter. This figure highlights the way in which the fluid moves in the Source : "A Method for Meaningfully Evaluating the Performance of a By-Pass Centrifugal Oil centrifuge. The oil enters the oil filter near Cleaner", Andrew Samways and Ian M. Cox, L. SAE Tech Paper 980872 the top, andexits at the bottom. Calculations have shown that the oil entering the oil filter is laminar. At the minimum rpm of 3000 rpm our calculations have shown that a 1-micron particle will hit the wan of the centrifugal oil filter. It should be stated here, that while these calculations give us a general understanding of the fluid dynamics and the fo rces required to separate the waste particles fromthe dirty oil, the calculations are not exact. The calculations in this section are based on the forces acting on the oil being independent of time. The exact solutions to these fluid dynamic problems are not independent oftime. For accurate calculations, a computer model would have to be done. For the purposes of our design we will rely upon these calculations and experimental discovery to determine the required rpm toclea n the oil in an automobile. 9.1 :Introduction to Torque Calculations Any or gaseous medium some amount of 27 torque is required to spin the object. Automobile oil is an extremely viscous medium. To design a centrifugal oil filter we must as a team determine the required torque needed to spin the rotor to the required rpm. As mentioned in the previous section, these calculations are independent of time and therefore are merely meant as a theoretical starting point for our design. The actual required torque will be higher thanthe torque that is calculated in this section. The calculated torque is meant as the starting point for subsequent experimental discovery. 9.2: Torque Calculations The fo llowing calculations are based on a model of a steady fully developed flow between two concentric cylinders. The outer cylinder is rotating and the inner (#2) cylinder is fixed. Both cylinders are oflength L. Since the pressure does not vary (#1) with 8, and we have an element of a thin cylindrical shell, the resulting torque acting on the element is zero since there is no angular acceleration. The resulting equation is: 0 (Eq. [7] r2rcrL*r - ( r + dr)2JT(r+ dr)L*(r + dr) = 12) The length of the cylinders (L) must be larger than the gap between the two cylinders. This is so the three-dimensional ends effects can be avoided. The resulting equation becomes: 0 (Eq. [7] dr = 2r+r 13) dr The shear stress equation for cylindrical coordinates: [ ] VB B (Eq. [7] T = ) _!_ 0v jlr !!_a- ( + oe 14) r r Using one-dimensional constitutive and the equation for shear stress becomes: 't=-'tre , (Eq. [7] 15) Plugging equation into equation we get: 14 12 28 (Eq. 16) [5] We divided equation 15 by �-tr and multiplied by dr, then integrated and rearrangedto get: dv8 v8 +-=A (Eq. 17) [7] -dr r We multiplied equation 16 by r dr and then integrated again to get: A B v8(r) =-r+- (Eq. 18) [7] 2 r The boundary conditions are v 8 = r1 OJ1 at r = r1 , and v 8 = r2 OJ 2 at r = r2 , so with the boundary conditions we get equations 19 and 20 fo r the constants, A, and B. (Eq. 19) [7] (Eq. 20) [7] Now evaluating equation 14 at r r2, we get the shear stress, and plugging that shear = stress into equation 20 The Surface area is equal to: Area = 277YL (Eq. 21) [8] Power = OJTorque (Eq. 22) [8] (Eq. 23) [8] 29 Oil's viscosity Two Cylinders, Outer is rotating and the Inner is Fixed, decreases significantly as the Oi! is in between the !'N o cylinders : SAE Automobile Oil 1 OW -30 oil's temperature increases. Due to this the torque 0.25000 E' ...... _ required to spin something e."' 0.20000 [ Torque ::> (Nm) : 2000 RPM � Torque (Nm) : 3000 RPM in oii decreases. Utilizing 0.15000 1·1 ·-�····•-·· Torque 1- (Nm) : 400 "C � � 0.10000 the mathematical model we lia. 0 0 0 0 0 torque curves for the model "' 0 "" "' � at 2000, 3000, and 4000 Oil Tern perature (deg C) rpms. Figure 9.1 shows the Figure Torque vs. Temperature @ RPM 9.1: 2000, 3000, 4000 three torque curves. It is important to note two things. The first is that at a Required Power (W) spin a cylinder in SAE to 10W-30 Mo1Dr Oil Over a Temperature Range -> deg C of 0 120 : fixed temperature, it takes and RPM @ 2000, 3000, 4000 more torque to spin the 120.00 outer cylinder to a higher 100.00 ··-+····· U):t: rpm. Second, at a fixed rpm, Pow er (Watt) : 2000 , 80.00 RPM I Power (Watt) : 3000 I it becomes easier to spin the �0 D. 60.00 RPM 'I � Power 1 outer cylinder, the higher i.... � (Watt) : 4000 40.00 I RPM ·s I J the temperature of the oil. l 20.00 Figure 9.2 is the resulting 0.00 0 0 0 ('J N � 8� &3 g � power th at would need to be Temperature (deg C) supplied in order to deliver Figure Power vs. Temperature @ RPM the required torque in figure 9.2: 2000, 3000, 4000 9.1. 9. 3: Conclusion Oil is an extremely viscous medium. For that reason the team needed to calculate the torque that is needed to spin the rotor automobile the opening paragraph calculations are independent of time. The exact 30 of the torque that is needed would require the team to create a computer model that would take up a significantly large amount of time. Although the numbers that were calculated are low, they are not as low as would first seem. The calculations arebased on the model of a smooth cylinder inside of another smooth cylinder with the viscous medium in between the two cylinders. Oil is not only viscous, but it is slippery, it is for this reason that it is used to lubricate a car's engine. The outer smooth spinning cylinder is not displacing any oil. If the outer cylinder as it moved displaced any oil, the required torque would then be significantly higher. Our design fo r a centrifugal oil filter consists of a smooth cylinder inside of another cylinder. For that reason the model the team used in this section is a good beginning to determine the torque that is needed to spin the oil filter to the rpmrequired. 31 10.) Centrifugal Oil Filter PrototypeDesig n 10.1: Introduction to the Centr�fugalOil Filter Prototype Once the team had completed the initial torque, rpm centrifugal force calculations. We constructed an initial centrifugal oil filterprotot ype. this section there are tvvo photos that highlight the centrifugal oil filter prototype. Also discussed in chapter is some of the initial design testing that we have completed on the prototype. This prototype is an extremely rough design. is only meant as an initial working It demonstrator of our theoretical design for centrifugal oil filter. This is not final design. 10.2: Design and Construction of Centrifugal Oil Filter Prototype The next step the team took designing an environmentally friendlyoil filterwas to create a crude working prototype. To do this we utilized an old kitchen blender as our base and motor supply. Figure 10.1 shows the prototype setup. To the blender's base and motor we affixed a clear Lexon tube that had previously had a bottom put on it. To act as a support and protection in case of any Figure PrototypeFilter attached to Variac (Black 10.1: fluid) leaks or mechanical failures, the team placed a thick protective Lexon tube around the outside of the rotating container that contained the dirty oil. The team then removed the check valve and attachment piece from a conventional oil filter and affixed it to the top of the prototype oil filter. This was Figure Prototype Top 10.2: 32 that the team would later be able to use the prototype oil filterwith the test apparatus (See Section 12 Photo 12.4 where the oil filter's mounting point is clearly shown). The team has conducted some initial testing of the prototype filter with promising results. First a small sample of dirty oil was poured over a small piece of filterpa per. Once the oil had fu lly drained, the filter paper was then examinedunder a microscope. The microscope allowed the team to gain some understanding as to what was in the oil, and how big the waste particles were. Once we knew what was in the dirty oil the team proceeded to run some initial tests with the prototype. Dirty oil was poured the oil filter. The prototypewas accelerated to 2000 rpms and allowed to run for 3 min. A sample of oil was then extracted from the center of the spinning prototype. The sample was then place on another piece of filter paper and allowed to drain. Once the sample had drained, the team looked at the filterpa per under the microscope. As we had anticipated the principle of centrifugal force had indeed separated some of the waste particles from the oil. The filter paper was by no means clean, but it did have significantly fewer waste particles then the first sample of filter naner- we --had examin-ed nn----der-- th-- e ----micms- --con- e � r r · · .L 10. 3: Conclusion of Initial Centrifugal Oil Filter Build This prototype is an extremely rough design. As a team we still have a significant amount of work ahead of us in the design of an environmentally friendly oil filter. This prototype and the results from the initial testing are encouraging. In principle the team had verifiedthat centrifugal force was a viable means of cleaning the dirty automobile oil, now the team has in practice, verified that the idea of centrifugal force. 33 11.) Ceramic Oil Filter Prototype 11.1: Introduction to the Development of a Ceramic Oil Filter As alternative to the centrifugal automobile oil filterthe team has decided to an develop an oil filter that utilizes a ceramic monolith as the filtering medium. It is unclear at this time if the ceramic oil filter will be an alternative to the centrifugal design or a better solution to our design problem. This section will describe in detail three things, why is the ceramic monolith a good design alternative,the ceramic monolith we have chosen to use, the Panasonic FT 1168, and the section will describe the holding apparatus that has been designed as the holder for the ceramic monolith. 11.2: Wh v Would You use a Ceramic Monolith ? Prof. Yiannis A. Levendis [10], proposed the idea that the team investigate the use of a ceramic monolith as an alternative to the centrifugal oil filter design. The ceramic monolith offers one large benefit, as a filter it has a significantly larger filtering surface area (GSA). Below are the equations used to compute the GSA of a 200/12 and a 100/17 Panasonic Ceramic Monolith. GSA(200/12) 23.7(Length)(Fronta!Area) = GSA(l00/17) l6.7(Length)(Fronta!Area) = The filtering surface area of a filteris the area within the filter that the medium comes in contact with. The ceramic monolith has a larger filtering surface area due to a series of cavities in the ceramic. The ceramic monolith picture on the next page, Figure 11.1, is a 200/12. The monolith has a filtering surface area of2,340.0 in/\2. A conventional Fram® oil filter has a filtering surface area of 186.2 in/\2. The monolith pictured in Figure 11.1 is slightly larger than a conventional automobile oil filter. For a ceramic monolith of the same dimensions as the Fram® oil filter, the GSA of the ceramic monolith is roughly ten times larger than the Fram® oil filter. As a by-product of this increased filtering surface area the car owner will theoretically to go an oil change for 30,000-50,000 miles. Although 34 12.) Testing Apparatus Our design problem is not as simple as it would first seem. Not only must we design an oil filterbut we must develop and build a test fixture to test them. The test fixture must simulate the oil system of a car. addition to that we determined that we must be able to measure the efficiencyof each filterdesign and compare it to that of a conventional automobile oil filter. section will describe thetest fixture as a whole, its individual parts, and the efficiencytesting of the overall testing apparatus. 12.2: Development of an Oil Filter Testing Apparatus The prototypes were designed in such a way that it would work with a testing apparatus. Although the method we used to initially test the prototypes was fine, a more permanentmethod was needed that would simulate a car's oil system. The team designed a testing apparatus that we could not only test the prototypes on, but also any existing oil filter on the market today. Figure 12.1 is a photo of the final oil filter testing apparatus. With this setupthe team will be able to not only test the prototype Fig 12. 1: Te sting Apparatus filters, but also as can be seen in the photo, test a conventional automobile oil filter. Key to the test setup is the pump. For our test setup to simulate a car there must be a circulating oil flow. To create the oil flow a simple oil pump and motor Fig 12.2: Pump and Pump Ho using 37 were needed to simulate a car engine's oil pump. The motor can spin to well over 3000 rpms so for safety reasons a protective housing was designed to protectthe user in case of any mechanical failure. The white Tupperware® container that is located in front of the pump is an oil reservoir. To better simulatea car, the oil reservoir was included so that we might place several liters of oil in the test setup. The mixing chamber, which is pictured to the right (Fig. 12.3) was included in the overall test fixture design to allow the team to place dirty particles in a place where they would encounter the filter before entering the reservoir, or more importantly the oil pump. The oil pump cost the team nearly $100, therefore anything we can do to Fig 12.3: }, 1ixing Chamber protect it will allow the pump to work for a longer time. The brass nut in the top of the mixing chamber is the place where the waste particles are introduced to the system. Prior to running a test the oil is drained from the mixing chamber by cranking the pump in the opposite direction to its normal rotational motion. The dirty oil is then poured in through the hole in the top of the mixing chamber. The pump is thenhand cranked in its normal direction to fill the mixing chamber with oil. Once these operations have been completed the pump is turned on and the system is allowed to run. 38 As was stated earlier, the test fixture was designed to allow both a conventional filter, and the prototype filter, to work on it. For the team to accurately determine the efficiency of our centrifugal design. The test apparatus must also be able to test our base filter. A Fram® Oil Filter was chosen as the base filter. Figure 12.4 Figure 12.4: Conventional Oil Fi lter shows a conventional Fram® oil filter on the test apparatus along with an oil pressure gauge. Figure 12.6: Light Source and Photocell Crucial to the design of a test apparatus for oil filters is the Efficiency Test. Figure 12.5: Effi ciency Test Apparatus How well does your design filterdirty oil? To accomplish this we decided to use a photocell our means of testing the filter's efficiency. The theory behind the use of the as photocell is quite simple. When a light source (See Figure 12.6) is shown through the oil, whether it be dirty or clean, the photocell registers some given voltage. As the opacity of the oil changes, that is, as it gets "darker" or "lighter," the voltage from the photocell changes. By using a photocell before after oil filter(See Figure 12.5) the of the two voltages. 39 13.) Work Completed as of Report A. Mission Statement Using existing oil filtersas our benchmark we will develop an oil filterthat is not only better for the environment, but will also act as a better oil filter. B. Financial Analysis • The design team determined that a centrifugal oil filter design was the most cost effective way of reaching our proj ect goal and mission statement. • The team determined the market price for a centrifugal oil filter based on 1,000 production units to be $100 e The initial target price of the centrifugal filter is $75 • We determined that the sales cost after 10,000 production units is $90. • We determined that the sales cost after 100,000 production units is $75. • We determined that the sales cost after 1,000,000 production units is $50. C. Patent and Literature Search • We researched and discovered six patents on centrifugal oil filters. • We discovered several textbooks on rotational fluid dynamics, such as, Rotating Fluids in Engineering Science by James P. Vanyo. • SAE Report # 980872 "A Method for Meaningfully Evaluating the : Performance of a By-Pass Centrifugal Oil Cleaner" by Andrew L. Samways and Ian M. Cox D. Initial Ideas • Three initial ideas were created by the team Angled Rotor Design + "Cheese Grater" Design + Impeller Design + e The design team constructed a design matrix and a "House of Quality". 40 • The team has chosen the Angled Rotor Design as its firstchoice. E. Mathematical Verification of Centrifugal Idea • The team determined that the oil flow is LAMINAR • Through mathematical computation, the Radial Velocity (Vr) was determined and graphed as a function of the diameter of the waste particles and the rpms of the centrifuge • The minimum particle size that will hit the wall of the centrifuge was graphed over a rpmrange of 1 000 to 10000 increments of 1000 rpms. F. Torque Calculations • The team utilized a simple model to compute the torque calculations. The mathematical model consisted of a fixed inner cylinder, a rotating outer cylinder, and a viscous material in between. The viscous material, in this case, was SAE 10W-30 Motor oil. • The Torque (Nm) required at 2000, 3000, and4000 rpms was graphed over a temperature range of0°C 120°C. -> • The Power (W) required at 2000, 3000, and 4000 rpms was graphed over a temperature range of l20°C. ooc -> G. Centrifugal Oil Filter Prototype • The first prototype was constructed out of a old blender. • Initial Testing was started, with promising results. • The prototype has verified that centrifugal forces are a viable means to filter dirty oil. Ceramic Oil Filter Prototype H. • Mathematical calculations completed. • Ceramic monolith container has been machined I. Test Apparatus • Test apparatus complete. • Testing conventional oil to that the testing apparatus works. • @3000 pressure system is approximately 15 psi. 41 14.) Work that needs to be completed • Ceramic Filter Design must be finalized. • Machining and material vendors must be contacted and catalogs purchased. • 3-D modeling and 2-D prints must be generated for Vendors. • Determination of whether or not future time and work should be put into the centrifugal oil filter design. Unfortunately the team has not been able to create an oil filter that meets our design requirements. We have investigated several design ideas that have looked promising, unfortunately we have confronted many problems. There is a significant amount of work that needs to be completed to design an environmentally friendly oil filter. The biggest problem is that of cost. Our research has shown that whatever design we decided to pursue it would have entailed a significant cost to the owner of the vehicle. At this point in the design process the best area of fo cus for the future efforts of the team would be to pursue the ceramic oil filteridea. 42 References [1] Mark Phillips, October 1996, "Filter Recycling Shifts Gears", Recycling Today [2] Interview : Philip Harper, Owner ofLumber Street Auto, Date : January 23, 1998, Subject : Discuss commercial viability of a more expensive permanent filter. [3] SAE Paper #980872: "AMethod for Meaningfully Evaluating the Performance of a By-Pass Centrifugal Oil Cleaner", Andrew Samways and Ian M. Cox [4] James P. Vanyo, 1993, Rotating Fluids in Engineering and Science (1st Ed), Butterworth-Heinemann (A member ofthe Reed Elsevier Group), Boston, pgs. 251-261 [5] James E.A. John and William L. Haberman, Introduction to Fluid Mechanics (3rd Ed), Prentice Hall, Englewood Cliffs , NJ. [6] Merle C. Potter and David C. Wiggert, 1991, Mechanics of Fluids (1st Ed), Prentice Hall, Englewood Cliffs , NJ. [7] Alexey J. Stepanoff, 1962, Centrifugal and Axial Flow Pumps (Theory, Design, and Application) (2nd Ed), John Wiley Sons, Inc., New York, Page 90-93 & [8] M.F. Spotts, 1985, Design ofMechanical Elements, Prentice Hall, Subj ect : Highlights some of the Mechanical Elements that will need to be designed for a new oil filter [9] Envirorunental Fact Sheet (#1303 a.1 1d #1304): "Properly Managing Used Oil Filters and Used Oil Filters Fact Sheet", Organization : Coordinating Committee for Automotive Repair ( CCAR - GreenLink ) , Subject : Toxic Characteristic Leaching Procedure (TCLP) and the way to properly dispose of used oil filters, Location ccar-greenlink. org/documents/ cat l 000 .html# 1300 : www. [ 1 0] SAE Paper #950370: " Diesel Vehicle Application of an Aerodynamically Regenerated Trap and EGR System", Fredrick Oey, Sandeep Mehta, and Yiannis A. Levendis 44 Appendix-A Financial Analysis of Oil Filter A-1 Rnancial 2/7/98 Total # of Filters sold in 96 : 420,000,000 Cost for a Fram Oil Fitter : 3.99 $ -fits most -8 American Engines V Total spent on Oil Filters in 1996 1,675,800,000 $ Assumptions in Recycling How much money can made in Recycling be ? 1.) Used Oil Alters in 55 gal drum 260 $ 10,096,153.85 2.) Drums to get 1 ton of steel 16 3.) #dollars /1 ton scrap 100.00 $ Environmental Issues Tons of Scrap Metal 100,961 .54 Average Individual Miles driven in a year (m) 15,000 Miles on 1 Oil Change 3,000 # of Oil Changes year 5.00 I Life of Car (years) 8 # of Oil Changes /life of Car 40.00 Cost to Car Owner Year I 19.95 Cost to Car Owner Life $ I $ 159.60 TargetCost for Oil Filter New fitter Paper Replacement 1.) Replacement Paper Element 15.00 2.00 $ $ Cost to Car Owner (1st)Year I $ Cost to Car Owner Year 23.00 I 10.00 Cost to Car Owner Life $ i $ 93.00 2.) Mechanical Design 100.00 $ - moving parts -availabilty to be left on car Cost to Car Owner Year I 100.00 Cost to Car Owner Life $ I $ 100.00 Page 1 Appendix-B Initial Oil Filter Designs B-1