Variable Intake w/ VVT
Variable Intake w/ VVT
(OP)
Hello, as a final school project i would like to design a system that uses both constant variable valve timing along with constantly variable intake. This would be for a race engine setup. Basically telescoping intake runners, that are synced to the cam variation as well. Change in both is based on engine load and throttle position.
1) is factoring engine load necessery for this to work effectively, or is throttle position enough?
2) What kind of setup would be best for the motorization of the telescoping intact tracts?
3) Im thinking electro magnetic magnets for the VVT system, (unless the project scope allows me to use a current manufactureres VVT system, and then i just integrate the variable intake..)
1) is factoring engine load necessery for this to work effectively, or is throttle position enough?
2) What kind of setup would be best for the motorization of the telescoping intact tracts?
3) Im thinking electro magnetic magnets for the VVT system, (unless the project scope allows me to use a current manufactureres VVT system, and then i just integrate the variable intake..)





RE: Variable Intake w/ VVT
Regards
Pat
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RE: Variable Intake w/ VVT
Or would it be easier to simply have both controlled exclusively by RPM?
RE: Variable Intake w/ VVT
If you want more power available at wide open throttle, you adjust inlet manifold runner length and camshaft timing to optimum for that rpm and have it automatically adjust to changing rpm. It can be by a simple bob weight system.
Cam timing is relatively easy re indexing. Changing duration and lift seamlessly is a whole other ball game. Computer controlled pneumatics, electrical/magnetic or a 3D camshaft are all I can think of as possible. I doubt it can be done to be durable with existing technology at a budget a mere mortal could contemplate.
On the fly seamless adjustment to intake runner length also has issues, mainly re friction air leaks and speed of change required.
The air leaks could be resolved by placing it in a box or by placing it upstream of the throttles.
Regards
Pat
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RE: Variable Intake w/ VVT
- Steve
RE: Variable Intake w/ VVT
Mikah B.
www.allanglesdesign.com
RE: Variable Intake w/ VVT
I forgot what I was going to say
RE: Variable Intake w/ VVT
Regards
Pat
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RE: Variable Intake w/ VVT
Greg50H - I am not quite sure what you are doing but it sounds interesting.
You may be also interested to see the following:
http://www.helicalcamshaft.com/
http://en.wikipedia.org/wiki/Helical_camshaft
This is one of the very few (maybe the only?) mechanical varible duration system that exists. Note that the website shows a short video showing a basic control and actuation arrangement by centrifugal means.
RE: Variable Intake w/ VVT
thinking back, you are right in that length only needs to be influenced by RPM, no matter what the engine load is, is you need 100% power at 2000 rpom or 7000 rpm (coming out of a corner-lifftle throttle, then roll onto it quick)-engine will still produce its best torque when the intake is at its helmholtz resonance.
Now, will the intake adjustment process have to be synced in time with the constantly variable cam adjustment to work to its fullest capacity? (i will be sticking with a conventional camshaft-3d and helicals are cool-but that is a project to deal with on its own accord), as in-will the length of the runner have to compensate for the advancement/ratardation of the cam?
RE: Variable Intake w/ VVT
Regards
Pat
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RE: Variable Intake w/ VVT
RE: Variable Intake w/ VVT
The centrifugal advance mechanism on a diesel injector pump camshaft may give you a few ideas.
I have read that the "Varicam" (or whatever it was called) did operate OK but had little or no measureable effect on the engine output.
I think if you are going to work with conventional camshafts you are not going to get any real results that could be applied to a racing engine. A lot (maybe most) of manufacturers already have continuously variable valve phasing - BMW's Vanos being a notable example.
To get worthwhile improvements in performance I think you need to work with variable duration. Honda's variable duration VTEC (although stepped and not continuous) demonstrates how effective variable duration can be.
RE: Variable Intake w/ VVT
BMW also had a variable lift system by simply moving the fulcrum on the rocker arm thereby changing rocker ratio.
Regards
Pat
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RE: Variable Intake w/ VVT
RE: Variable Intake w/ VVT
PP - BMW's Valvetronic (if that is the system you are referring to) is not just variable fulcrum but an "oscillating cam" system of linked variable duration and variable lift.
Greg - Just what do you mean by "variable intake"? variable lift, duration or length of the intake tracts?
RE: Variable Intake w/ VVT
www.pattakon.com
RE: Variable Intake w/ VVT
Nice find.
Regards
Pat
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RE: Variable Intake w/ VVT
RE: Variable Intake w/ VVT
You could however just set the cam phasing first and then adjust your runer length based on rpm only.
I always looked at this project to - and I just looked at using a DC motor controlled ball and screw setup.