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Quick instructions

Long story short get a suitable sized jar that can withstand heat, oil, and vibration (preferably heat resistant plastic). Feed your pcv hose into the jar and then feed from the jar to the intake. For those of you that want more detailed instructions and specifications continue reading.

I am taking part in an Auto-CAD course in Highschool. For our culminating project each of us were given the task of designing and building an oil catch can. We tested a total of ten different designs. The following is a detailed description of how to build your own catch can, the concepts behind our designs and how well they performed during testing. P.S. This catch can is not meant to be pretty it is designed to work and be extremely cheap








 
How to Make

Tools/safety equipment
Drill
Hot glue gun
Safety glasses

Materials
Large jar at least 2” diameter preferably 4” (calculations for finding jar size at end)
Tubes ¾” ID (internal diameter)
Glue

How to make
1 First clean the jar making sure to remove all materials from the inside of the jar.
2 Second remove the lid and drill holes just large enough to get the tube into.
3 Then feed the tubes through the holes keeping one tube higher than the other but make sure to not push the tubes farther than 1” into the lid. This helps prevent the air coming into the can and then immediately leaving the can. The higher tube is where the clean air will leave the jar and the lower tube is where the oil filled air will be coming into the can.
4 Next glue the tubes in place both inside and outside of the lid.
5 Reattach the lid and you are done making the can.

Can attachment
To attach this can all you need to do is cut your pcv hose and feed your pcv hose into the jar and then feed from the jar to the intake.
Also make sure that the lid is securely fastened down.
You may want to add a dab of glue to make sure the lid does not come loose.

How we made and picked the best design



Safety equipment:
The first thing we must do is ensure we have all of the proper safety equipment. This should include the following.
Protective Glasses
Gloves if necessary
Long Sleeve shirt

Test Equipment:
Airline Lubricator
Model: Mettle Air AL 2000-02
Rated Flow: 800 L/min variable flow rate
Port Size: 1/4" NPT
Bowl Capacity: 〖25cm〗^3

Air Pump
150 psig 50 gallon air compressor

Connectors Tubes and Clamps
quick connecter

Weigh Scale
Acculab Vicon - accurate to within one one-hundredth of a gram

Procedures

Throttling

Air throttling
The air was throttled to approximately one-quarter maximum flow rate.

Oil throttling
The oil inlet was throttled to allow only partial flow of oil. This can be adjusted as needed in testing as long as all cans are tested with the same throttle rate.

Pressure used
150 psig

Duration of the test
1 min per can

Measuring oil caught
We measured the weight of the cans before and after the test. We then used the weight differential to determine the total amount of oil caught by the can.

Different designs

Tim’s Catch Can
The idea behind this catch can was that it would enable the catching of liquids in general and not be limited to oil.



Kendra’s Catch Can
The idea behind this catch can was that it is simple to make and extremely compact.


Jared’s Empty Big Catch Can
The idea behind this catch can is that it will slow the air below 1m/s which will allow gravity to remove the oil from the air.
To make this design I calculated the amount of blow by that would be coming from the engine. I then designed a can that would slow the air below the minimum m/s in a worst case scenario. (calculations at end)


Jared’s Electrostatic filter Catch Can
The idea behind this catch can was that it would filter the air by collecting the small particles of oil.


Jared’s Empty Small Catch Can
The idea behind this catch can was to provide a base to compare all the other catch cans too.


Jared’s steel wool Catch Can
The idea behind this catch can was to cause air turbulence which would increase the condensation rate.


Evan’s Catch Can
The idea behind this can is that the wire wool and other materials will act as a filtration system that prevents oil from escaping the can.


Sam’s Catch Can
The idea behind this catch can is that it will slow the air below 1m/s which will allow gravity to remove the oil from the air. It was also assumed that by adding an absorbing material in the bottom of the can that it would promote the collection of oil.



Results

Different cans and statistics

Tim’s Catch Can
Starting Weight - 265.7 g
Ending Weight – 267.1 g
Total amount of oil caught – 1.4 g


Kendra’s Catch Can
Starting Weight – 217.4 g
Ending Weight – 218.5 g
Total amount of oil caught – 1.1 g


Jared’s Empty Big Catch Can
Starting Weight – 217.1 g
Ending Weight – 223.6 g
Total amount of oil caught – 6.5


Jared’s Electrostatic filter Catch Can
Starting Weight – 134.6 g
Ending Weight – 136.8 g
Total amount of oil caught – 2.2 g


Jared’s Empty Small Catch Can
Starting Weight – 128.3 g
Ending Weight – 133.5 g
Total amount of oil caught – 5.2 g


Jared’s steel wool Catch Can
Starting Weight – 154.51 g
Ending Weight – 156 g
Total amount of oil caught – 1.49 g


Evan’s Catch Can
Starting Weight – 94.5 g
Ending Weight – 99.7 g
Total amount of oil caught – 5.2 g


Sam’s Catch Can
Starting Weight – 101.92 g
Ending Weight – 103.56
Total amount of oil caught – 1.64 g



Compare

Best Design
Jared’s Empty Big Catch Can is the can that caught the most oil during the testing.


Reasons why it worked better
The reason it worked the best is likely because of its size. I found that in a worst case scenario that I would need a can that was two inches in diameter to allow the oil to drop out of the air naturally. I then designed this can to be twice the height and width. This gave the can seven times the volume of the other cans tested. I also used larger tubes to slow the entry speed of the air and reduce turbulence further slowing the air. Thus giving the oil more time to be pulled of the air due to gravity.


Conclusion

Does the can lower the amount of oil residue buildup in the engine.
yes

Were we successful in finding the best design for an oil catch can?
yes

Does the oil catch can meet all expectations?
yes

What are some ways that the design could be improved?
We could improve the design by angling the tubes to give a cyclonic effect thus utilizing not only gravity but also centrifugal force.

Recommendation

My recommendation is to obtain an oil catch can that does not contain any filter medium but rather has a larger interior space.
I would also recommend that the connecting tubing be of the largest diameter convenient so as to slow the air down before it reaches the oil catch can.





Calculations

These are the equations to find out the size of catch can you need for gravity induced oil collection.

In my case I have a 2.4 Liter engine. I am assuming 4000 rpm running speed. With 90 percent Volumetric efficiency which means although I have a 2.4 Liter engine I am assuming it is only taking in 2.16 Liters of air. I am assuming a worst case scenario of 3% blow by (air escaping into the crank case). The equations for this scenario are a rough estimate to determine what size of catch can you will need. Feel free to change the numbers in the equations to fit your particular car.


S=Engine Displacement (in liters)
N=engine speed (in RPM)
VE=volumetric efficiency
V=volume of blow by (in liters per minute)

S=2.4 L
N=4000 rpm
VE=90%
Blowby rate=3% (0.03)

V=(N*S*VE)/2*Blowby rate
V=(2.4*4000* .90)/2* 0.03
V=129.6 Liters per minute



A=cross sectional area of catch can (in m^2) Vb=blow-by volume (in liters per minute) Vc=Critical speed for oil drop out (in meters per second)

A=(Vb*0.0000167)/Vc
A= (129.6*0.0000167)/1
A= 0.00216432 m^2





A=cross sectional area of catch can (in m^2)
D=diameter of circular volume (in mm)

D=1000* √(4 *A)/π
D=1000* √(4 *0.00216432)/π
D=1000* √(0.00865728)/π
D=1000* √0.00275569781146120730489048405394
D=1000* 0.05249474079811431267117455923545
D=52.5 mm


I then made my catch can with double the diameter just for good measure.

... Wait, what? Why would you do this?

I still really want to make a catch can, but I'll have to make something that looks nice under the hood. I realize I'm being very picky, but I hate pulling my intake manifold and sticking my fingers into the runners and getting oil all over my fingers. And I mean $30 catch can hate it, too. I've worked on a lot of oily cars and like my personal ride to be as different as customers' as possible.

Neat!
Was this a class room engineering project?

kumquat The reason for doing this is to prevent the blow-by (oily air) from getting into your intake. This is because when it does it lowers your fuel efficiency and can generally gunk up the works. hope this helps

SeattleJeremy This was actually the second semester of an auto-cad course in high school. We had learned much of how to use auto-cad and so the teacher wanted us to become more familiar with the process of making a formal report. We however were told instead of submitting it to the teacher we had to post it online for others to use. yup we be nerds

lannvouivre Its fine if you do not want to use this particular design however the calculations at the end should help you decide what catch can would be best for your car. Hope you find one that works for you

For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. John 3:16

Nicely done! Have you tested it on your car yet?

What do you mean when you say oily air reduces fuel efficiency? I don't quite get it, if you were to vent the crankcase into the atmosphere you would get the same mpg. Besides the EGR valve gunks up the intake much worse than the crankcase ventilation.

gtv237 wrote:What do you mean when you say oily air reduces fuel efficiency? I don't quite get it, if you were to vent the crankcase into the atmosphere you would get the same mpg. Besides the EGR valve gunks up the intake much worse than the crankcase ventilation.

Seems kinda dubious to me. If a $10 can could improve fuel efficiency it's a pretty safe bet that Toyota and every other manufacturer would be using them to meet those tough CAFE standards.

kumquat
I will concede that the catch can does not immediately increase efficiency however not using one decreases efficiency over time. Take into consideration the following, "For an engine to produce the maximum amount of energy per explosion (of the A/F in the combustion chamber) you want air & fuel only….any amount of oil in this mix will hamper the explosion resulting in less energy released, detonation, and carbon buildup. Trapping and removing this oil before it gets into the combustion chamber is the ONLY solution to maintaining the maximum efficiency and prevent excess carbon buildup. A correctly designed and installed Oil Catch Can solves this problem." The reason that car manufacturers do not include a catch can is because it is a maintenance item and takes up space. Further more even a $10 catch can adds cost. It may seem insignificant when said it only costs $10 but $10 x 100,000 is a lot of money. Then take into account that they would have to make it out of better material than what I used. This would drive the cost up even further. Imagine $25 x 100,000. I must also point out that there have been problems in newer cars with direct injection due to carbon build up now that fuel is no longer washing the intake valves. Furthermore in regards to how dubious the fact of the merits of using a oil catch can is I would suggest reading the following. Hope this helps



sources:

http://oilcatchcan.com/" onclick="window.open(this.href);return false;

http://auto.howstuffworks.com/positive- ... system.htm" onclick="window.open(this.href);return false;

http://www.edmunds.com/autoobserver-arc ... pters.html" onclick="window.open(this.href);return false;

http://www.z28.com/threads/oil-catch-ca ... d=noscript" onclick="window.open(this.href);return false;



gtv237
I beg to differ the EGR valve opens mostly near idling speed and as such is not running constantly. The practice of using the EGR valve also has been shown to increase fuel efficiency at low rpm which is the main reason they are used. Also in regards to catch cans increasing efficiency it mainly is concerning efficiency lost over time and reduced engine life. References above. Hope this helps


Chiadog
No I have not.

For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. John 3:16

The OP should also realize that the $10.00 can when purchased in huge quantities the per unit cost would likely drop to less than a $1.00 each.