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DEVAS Digital Electro-hydraulic Valve Actuation System


Guest TeamNissan

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Guest TeamNissan

I know I am not the only one interested in learning more about this system and info online is a bit sketchy so I thought it would be nice to have a thread were we could all share or knowledge on it.

 

Sadly I'm not qualified to do a write up on this although I do know the theory of operation and benefits this system holds.

 

Here is a basic description of the system for anyone know doesn't know what I am referring to.

 

http://www.hibeamauto.com/hightech.htm

 

The thread is here now though so I hope we can get the ball rolling.

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Guest TeamNissan

Thank you Tony.

 

I'm curious has anyone on here been experimenting at all with this kind of set up or even planning to? I know I have seen some mention of it here and there. It seems the ground work is even already laid. There are stock motors using it like the ford 6.0 diesel, for years now. Just seems so amazingly beneficial to me I suspected more people would be into it. Am I missing something? Only 1 reply in 4 days :-(.

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From what I can read in the link you posted, the POWERSTROKE uses the INJECTERS only.

 

Very interesting idea, Looks extremely expensive though

I guess that once you eliminated all the timing hardware, cams and oil passages internal to the head, it might compensate for the cost. Plus, once the technology comes out and more and more parts are produced, the prices are going to go down, electronic components are getting cheaper to produce by the minute.

 

I know for sure that we are anxiously waiting for this to come out, here at BMW, but the mother company is a bit shy about details. I heard they`re waiting to bring this out at the same time as the 48V. charging systems, we already have, on some models, the starter/alternator combined in a single unit though. From what very little I've seen so far though, the valves they are experimenting seem to be sliding valves, a bit like old motorcycle slide throttle carburetors, where the valve, instead of moving axially, would swing radially to a predetermined angle depending on the amount of opening needed. The head is diminished to the thickness of a valve cover and there's no more intake plenum, air would be contained in the head itself and fuel would be supplemented trough direct injection, no more oil needed in the head, no more timing apparatus hanging from the front and it makes for a surprisingly small engine...

 

I don't know much details for now, but I'll be sure to follow this tread, as it's immensely interesting and as soon as I have more info, I'll make sure to let you guys know. It's coming one drop at a time though, as all I know, I learned by poking the field engineers, whenever they drop by.

 

Thanks for starting this good tread.:mparty:

Alex.

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Guest TeamNissan
A single bad waveform from a sensor and the engine is done.

 

Point? There are a host of simple things that could ruin a CURRENT engine. At least with electrical you can work out a redundancy system to prevent it.

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Guest TeamNissan
From what I can read in the link you posted, the POWERSTROKE uses the INJECTERS only.

 

 

I guess that once you eliminated all the timing hardware, cams and oil passages internal to the head, it might compensate for the cost. Plus, once the technology comes out and more and more parts are produced, the prices are going to go down, electronic components are getting cheaper to produce by the minute.

 

I know for sure that we are anxiously waiting for this to come out, here at BMW, but the mother company is a bit shy about details. I heard they`re waiting to bring this out at the same time as the 48V. charging systems, we already have, on some models, the starter/alternator combined in a single unit though. From what very little I've seen so far though, the valves they are experimenting seem to be sliding valves, a bit like old motorcycle slide throttle carburetors, where the valve, instead of moving axially, would swing radially to a predetermined angle depending on the amount of opening needed. The head is diminished to the thickness of a valve cover and there's no more intake plenum, air would be contained in the head itself and fuel would be supplemented trough direct injection, no more oil needed in the head, no more timing apparatus hanging from the front and it makes for a surprisingly small engine...

 

I don't know much details for now, but I'll be sure to follow this tread, as it's immensely interesting and as soon as I have more info, I'll make sure to let you guys know. It's coming one drop at a time though, as all I know, I learned by poking the field engineers, whenever they drop by.

 

Thanks for starting this good tread.:mparty:

Alex.

 

 

Actually all the research I have done on that engine suggests its a full set up and truely camless. Maybe I'm wrong?

 

I have been watching bimmer VERY closely too. I know they have some very interesting set ups coming.

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"Currently.........I know of no engine that will be mechanically ruined by a bad sensor input."

 

As an engineer for standard motor products ECU division, I can personally vouch for the fact that the most common sensor malfunction pertains to sensors that measure crank and cam angle..............regardless of manufacturer.

 

Any unusual waveform from a failing sensor can easily net you piston meeting valve in the setup being discussed here.

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Any unusual waveform from a failing sensor can easily net you piston meeting valve in the setup being discussed here.

 

That would not be as bad as it used to be...

 

If there's no cam above the valve stem, holding it open, if the piston was to touch the valve, the valve would go back in its hole pretty quickly.

 

And if any damage occurred to the valve, you'd just open the cover, remove the damaged valve "unit", drop a new one in...

 

As a bonus, in the system I'm referring to, the valves swing aside instead of being pushed in the chamber, so there's absolutely no chance of contact.

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Guest TeamNissan
That would not be as bad as it used to be...

 

If there's no cam above the valve stem, holding it open, if the piston was to touch the valve, the valve would go back in its hole pretty quickly.

 

And if any damage occurred to the valve, you'd just open the cover, remove the damaged valve "unit", drop a new one in...

 

As a bonus, in the system I'm referring to, the valves swing aside instead of being pushed in the chamber, so there's absolutely no chance of contact.

 

I was typing that and quoting your previous post, went to eat and got beat lol.

 

Do you know in what category bimmer will be 1st implementing this? I know some other European companies have sim designs coming but only for economy and industrial applications.

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Any unusual waveform from a failing sensor can easily net you piston meeting valve in the setup being discussed here.

 

Loss of signal is a 'failsafe' mode for the DEVAS system, and the engine shuts down.

 

The processors are two 140mhz CPUs and one 'abnormal' waveform would not do it. It would have to be a sensor that came loose or slipped position. It checks and crosschecks the relative positions of each sensor so quickly that any abnormality will cause a 'safe mode' operation, or valve shutdown.

 

Remember that these valves are not MECHANICALLY opened, so an impact of a piston to valve would likely 'bounce' the valve off the head, as oppose to 'squash' it between two immovable, mechanical items.

 

The dominant paradigm will get you in trouble when you apply your thinking to how the system operates. The hydraulic system only needs enough pressure in it to open the valve, a simply relief valve will allow this 'bounce' by immediately bleeding off hydraulic pressure should impact occur....

 

This is not your typical 100+ year old "Cam and Tappet" arrangement.

 

If F1 can use Desmodromic Valves (same technology, different actuation motive force) without incident, I'm thinking DEVAS is not as susceptible to 'abnormal waveforms' as you may think...

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I engineer engine management systems for a living and my experience in engine management systems design tells me this idea is not ready for prime time.

 

Believe me, I know the failure rates for sensors and what engine management systems do when fed the wrong information from said sensors.

 

Also...........the inertia of the valves and pistons moving in opposite directions at a pretty good rate is enough to bend the valves if they contact. They don't need a cam behind them to bend.

 

Formula one is not a good example as they suffer failures directly related to the valve actuation mechanism more than any other failure in recent years.

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I have been reading about people working on this idea for over 30 years. The physics of the problem hasn't changed much since then. :wc:

 

Anyone who thinks a piston in an engine spinning at 6000 RPM is just going to "tap" the valve closed has been drinking too much kool aid. Think of the forces involved. The electronic actuator will need to be just as strong as the mechanical one. The exact reason why this method has never gone into production.

 

Guess I don't need to worry about that nut I droped down my intake. The piston will just tap it back out again on the exhaust stroke. :icon44:

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