I thought this guy did a good job explaining how VVTI works. Just in case you are interested in knowing...
How VVTI works
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That was very interesting. Thanks for sharing. One interesting question would be, did the engineers who designed the oil control valve have any preference on the viscosity of the oil or does the feedback system adjust the amount of advance regardless of the viscosity.
Originally Posted by Snagglefoot
That was very interesting. Thanks for sharing. One interesting question would be, did the engineers who designed the oil control valve have any preference on the viscosity of the oil or does the feedback system adjust the amount of advance regardless of the viscosity.
I'm sure they took this into account, besides they can tell where the camshaft is at all times with the cam sensor so even if the viscosity affected it, it would know shortly thereafter.
That was very interesting. Thanks for sharing. One interesting question would be, did the engineers who designed the oil control valve have any preference on the viscosity of the oil or does the feedback system adjust the amount of advance regardless of the viscosity.
I'm sure they took this into account, besides they can tell where the camshaft is at all times with the cam sensor so even if the viscosity affected it, it would know shortly thereafter.
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Seem to remember that the cam phraser is only on the intake or exhaust cam ? Not both .
Our little red 2015 Chevy Sonic 1.8l has , I think , VVTI . I have tried to use only full synthetic DEXOS 5W-30 oil in it . I did not want th take the chance on the little oil passages sludgeing / stopping up . Or it or the phaser wearing out .
It has a timing belt , so no chains or chain guides to worry about .
Our little red 2015 Chevy Sonic 1.8l has , I think , VVTI . I have tried to use only full synthetic DEXOS 5W-30 oil in it . I did not want th take the chance on the little oil passages sludgeing / stopping up . Or it or the phaser wearing out .
It has a timing belt , so no chains or chain guides to worry about .
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Originally Posted by Snagglefoot
That was very interesting. Thanks for sharing. One interesting question would be, did the engineers who designed the oil control valve have any preference on the viscosity of the oil or does the feedback system adjust the amount of advance regardless of the viscosity.
I know in the case of the system Chrysler uses, which, on the HEMI, is only phasing the single camshaft, that temperature is a component factored into the fuzzy logic for determining rough viscosity (as is oil pressure) and so a gross departure from what the system expects can result in a code.
BMW's dual phasing system VANOS, which uses electronic solenoids and oil pressure, does not seem to be overly sensitive as they've spec'd everything from a fuel saving ILSAC 5w-20 to a 10w-60 in the same systems.
Given the wild variance in viscosity due to temperature, which is significantly more than what's observed between grades, these system simply cannot be intolerant in terms of absolute viscosity in operation. What they can be is sensitive to relative viscosity. That is, at say 180 degrees the system expects between 40-45psi and it sees 70, that could potentially cause issues or trigger a code if that's part of its program.
That was very interesting. Thanks for sharing. One interesting question would be, did the engineers who designed the oil control valve have any preference on the viscosity of the oil or does the feedback system adjust the amount of advance regardless of the viscosity.
I know in the case of the system Chrysler uses, which, on the HEMI, is only phasing the single camshaft, that temperature is a component factored into the fuzzy logic for determining rough viscosity (as is oil pressure) and so a gross departure from what the system expects can result in a code.
BMW's dual phasing system VANOS, which uses electronic solenoids and oil pressure, does not seem to be overly sensitive as they've spec'd everything from a fuel saving ILSAC 5w-20 to a 10w-60 in the same systems.
Given the wild variance in viscosity due to temperature, which is significantly more than what's observed between grades, these system simply cannot be intolerant in terms of absolute viscosity in operation. What they can be is sensitive to relative viscosity. That is, at say 180 degrees the system expects between 40-45psi and it sees 70, that could potentially cause issues or trigger a code if that's part of its program.
Depends on the engine.
My 2001 and 2002 Volvos have a VVTi phaser on the exhaust cam only.
In 2005, Volvo added a phaser to the intake cam, too.
The engines are otherwise the same, same parts fit all of them, but the HP went up a bit with the intake cam phaser, and the ECU and wiring harness have some differences.
My 2001 and 2002 Volvos have a VVTi phaser on the exhaust cam only.
In 2005, Volvo added a phaser to the intake cam, too.
The engines are otherwise the same, same parts fit all of them, but the HP went up a bit with the intake cam phaser, and the ECU and wiring harness have some differences.
I wonder how much information the phaser algorithm monitors ?
Originally Posted by WyrTwister
I wonder how much information the phaser algorithm monitors ?
With how much information the PCM has today in total from all the other modules in a vehicle and all the sensors in the engine / transmission I would imagine it has to have some serious computational power and has to be monitoring a ton of different things all at once. I have often wondered what the speed of the CPU and all the memory it requires to do such tasks. It must be a nightmare for folks that have to update code when there is a recall or improvements that need to be made.
I wonder how much information the phaser algorithm monitors ?
With how much information the PCM has today in total from all the other modules in a vehicle and all the sensors in the engine / transmission I would imagine it has to have some serious computational power and has to be monitoring a ton of different things all at once. I have often wondered what the speed of the CPU and all the memory it requires to do such tasks. It must be a nightmare for folks that have to update code when there is a recall or improvements that need to be made.
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Originally Posted by Snagglefoot
That was very interesting. Thanks for sharing. One interesting question would be, did the engineers who designed the oil control valve have any preference on the viscosity of the oil or does the feedback system adjust the amount of advance regardless of the viscosity.
Maybe not viscosity but other attributes. For example BMW (VANOS/VALVETRONIC) system requires that the oil be free of air bubbles and of course the system requires relatively clean oil. The BMW system has little filters in the solenoids which usually end up getting replaced at least once during the life time of the vehicle.
That was very interesting. Thanks for sharing. One interesting question would be, did the engineers who designed the oil control valve have any preference on the viscosity of the oil or does the feedback system adjust the amount of advance regardless of the viscosity.
Maybe not viscosity but other attributes. For example BMW (VANOS/VALVETRONIC) system requires that the oil be free of air bubbles and of course the system requires relatively clean oil. The BMW system has little filters in the solenoids which usually end up getting replaced at least once during the life time of the vehicle.
There are screens (coarse filters) in each of the Volvo VVTi solenoids as well. I imagine that's an industry standard, to preclude actuation problems from dirty/neglected oil.
Originally Posted by StevieC
Originally Posted by WyrTwister
I wonder how much information the phaser algorithm monitors ?
With how much information the PCM has today in total from all the other modules in a vehicle and all the sensors in the engine / transmission I would imagine it has to have some serious computational power and has to be monitoring a ton of different things all at once. I have often wondered what the speed of the CPU and all the memory it requires to do such tasks. It must be a nightmare for folks that have to update code when there is a recall or improvements that need to be made.
Maybe not as much memory and computational power as you might suppose . It is a dedicated build , single purpose computer . Where as your PC is a general purpose computer . And it does not have to have all the overhead of a Graphics Interface Unit .
For example , Windows consumes a large amount of overhead . Add to that , many of the functions do not have to be monitored every nano second . Those functions may be polled ever so often .
Add to that , computational power and memory seem to drop in price every year .
Originally Posted by WyrTwister
I wonder how much information the phaser algorithm monitors ?
With how much information the PCM has today in total from all the other modules in a vehicle and all the sensors in the engine / transmission I would imagine it has to have some serious computational power and has to be monitoring a ton of different things all at once. I have often wondered what the speed of the CPU and all the memory it requires to do such tasks. It must be a nightmare for folks that have to update code when there is a recall or improvements that need to be made.
Maybe not as much memory and computational power as you might suppose . It is a dedicated build , single purpose computer . Where as your PC is a general purpose computer . And it does not have to have all the overhead of a Graphics Interface Unit .
For example , Windows consumes a large amount of overhead . Add to that , many of the functions do not have to be monitored every nano second . Those functions may be polled ever so often .
Add to that , computational power and memory seem to drop in price every year .
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