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phaser Oil control valve square wave or?

1K views 8 replies 2 participants last post by  charosenz 
#1 ·
Can someone tell me if the Oil Control Valves are simply opened - and kept open - at a designated condition......Or.....are they opened and closed rapily many times a minute using a square wave impulse.


I am building up an off road racer and I am not going to use the OEM ECU, but I certainly could open and close them at a specific RPM. I am just not sure if they are typically operated that way. I.E. Open and kept open above a certain RPM, and closed and kept closed below a certain RPM.


I saw something somewhere that suggested it was operated with a square wave that opened and close many times a minute. But I am very doubtful that is needed, or desired. It would seem really weird to be changing the intake or exhaust cam timing rapidly.


I am hoping some will know the answer and not guess at it.


I appreciate the help.


Charlie
 
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#2 ·
Well since vvt isn't just a simple on/off operation it would mean that the solenoids aren't just on/off. Many stand alone EMU's have VVT capability these days, just pick one that does and you're good to go!

VVT is varying continually based on multiple inputs, it's not like vtec where it's on at X rpm. Going full one way or the other with the cam won't really be beneficial except to make a very lumpy narrow power band with harsh peaks at certain RPM and dead spots at others, it's designed to vary timing across a rpm range and can be very effectively exploited to keep torque pretty flat.
 
#3 ·
Sorry, I must not have made myself clear. Yes, the valve is adjusted by the ECU primarily based on RPM based on data from the cam and crank sensor. Water temp and load (MP) are also secondary criteria the system looks at.


I was really looking for more detail on the Pulse Width Modulation Signal and whether or not that was used to open and close the valve frequently only varying the time open or closed when condition change, or if the PWM simply was the method used by the ECU to open and close the valve only when conditions change.
 
#4 ·
the position of the valve is not steady, it varies based on ECM inputs. The gear has a spring loaded mechanism which locks it for starting when no oil pressure is present. If you want the engine to run properly you'll need a EMU that does VVT, there's plenty of them out there like the PFC, Hydra, Pro EFI, AEM, etc. You just plug in the advance/retard to a table like you would fuel and ignition values, most come with a base map preloaded to get the engine up and running.
 
#6 ·
You asked if it's an on/off or PWM. It's PWM, probably square wave, but it doesn't really matter since there's at least half dozen stand alone a piggy back units that'll run VVT right off the shelf. I think even the DIY system has that capability now or has an add on card for it.

The valve itself is spring loaded and has oil pressure pushing on it when the engine is running so it needs a constant amount of drive to maintain any one position and then a change in drive to change position.

Is that what you were looking for? It sounds like you're trying to reverse engineer something that's already been addressed and resolved for about 10 years now. Just get a piggy back or standalone for the vehicle application that engine is used it and take it to a tuner familiar with that system for some dyno pulls and tuning. The VVT will work properly and enhance the power output when properly massaged by a good tuner.
 
#9 ·
If you stick to providing answers that relate to the question you'll be fine.

The problem is your seemingly inate desire to tell people what they should or should not do. It's unwanted. Not helpful. Especially when you really have no knowledge of the project. You come across as "I know better".

Don't drag the thread off topic, with your own ideas that are OT (off topic) like you did with this thread - again!

Unless someone specifically asks for your "opinion" - save it.

Now let's move on to bigger and better stuff. No offense intended but if I could stop you for posting on threads I create, I would.
 
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