Trivia Question - Could gas engines get electronic valvegear?
John Bond
Posts: 369
Automotive engines are becoming very complex. Consider for example the soon to be released Audi 3 Litre engine that has a multi-lobe camshaft in addition to variable valve timing, variable boost supercharging and direct injection. ·The age of automotive complexity is upon us,,,
http://www.atz-online.de/index.php;do=show/alloc=1/lng=en/id=8076/site=a4e/sid=4eaede7964db3a4f75924c8c46523676
Most of this development is about the engine intake or “breathing”. Getting the charge and fuel into the cylinders has always been a problem. Valves and cams, as we know them, are very inefficient. They do not open at the right time, they bounce and then they do not close appropriately. Trouble is you need a different cam profile for each combination of acceleration, load and RPM (and probably many more variables).
What about opening the valves electronically?
Sounds far-fetched but piezo fuel injectors are becoming more common. They use a piezo stack to open the injector nozzle. Because this is quicker than either mechanical or solenoid valves and they are not cam controlled, the injection is much more efficient.
http://www.theautochannel.com/news/2008/04/16/084329.html
The questions are - How would one do it? Do you use a huge stack of piezo eliments or is there some other technology? Would you change how the valves work?
By the way, a Microchip engineer told me that Bosch, Microchip and BMW did·a little·research on Piezo Valves about 5 years ago but it appears to have been "Top Secret", no media releases nothing. I heard the engine sounded like a tractor and they couldn't suppress the "valve bang".
Just an offbeat question straight out of Darkest Africa to tax your brain.
John Bond··- Kwa Dukuza - South Africa
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http://www.atz-online.de/index.php;do=show/alloc=1/lng=en/id=8076/site=a4e/sid=4eaede7964db3a4f75924c8c46523676
Most of this development is about the engine intake or “breathing”. Getting the charge and fuel into the cylinders has always been a problem. Valves and cams, as we know them, are very inefficient. They do not open at the right time, they bounce and then they do not close appropriately. Trouble is you need a different cam profile for each combination of acceleration, load and RPM (and probably many more variables).
What about opening the valves electronically?
Sounds far-fetched but piezo fuel injectors are becoming more common. They use a piezo stack to open the injector nozzle. Because this is quicker than either mechanical or solenoid valves and they are not cam controlled, the injection is much more efficient.
http://www.theautochannel.com/news/2008/04/16/084329.html
The questions are - How would one do it? Do you use a huge stack of piezo eliments or is there some other technology? Would you change how the valves work?
By the way, a Microchip engineer told me that Bosch, Microchip and BMW did·a little·research on Piezo Valves about 5 years ago but it appears to have been "Top Secret", no media releases nothing. I heard the engine sounded like a tractor and they couldn't suppress the "valve bang".
Just an offbeat question straight out of Darkest Africa to tax your brain.
John Bond··- Kwa Dukuza - South Africa
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Comments
Leon
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Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
It uses highly pressurized engine oil acting on an intensifier piston of between 5 and 7 times the surface area of the plunger acting on the fuel to be injected. So with oil pressure in the 3000+psi range it can easily produce force in excess of 20k psi.
You could use this technology and substitute the valvestem for the fuel plunger and let the hydraulic force from the intensifier piston force the valve open against a typical valve spring.
They are relatively quick (very quick relative to valvetrain speeds). They can actuate and de-energize in around 1ms. They are obviously quick and consistent as they are used for fuel injection on direct injected diesels.
I have often thought about using one of such an actuator for each valve.
Back in college I was in the SAE program. Every year, SAE holds an event in Detroit called "Congress". Everybody in the industry comes in and sets up a booth, including all the major makers, and suppliers. If one ever gets a chance to attend, it is well worth it, even if it is only once.
Anyway, one of the booths one year included a head with electronic valves. Basically following the same concept as the electromagnet. I recall the major limitation being the speed at which they needed to be actuated. I don't think they were able to get much more than a few thousand RPM's out of the system before hitting the wall. But, the demo was working, and sounded wicked cool. This was back around 1997-1998ish. So, the concept has been around for some time now.
Leon hit it in the head. Pneumatic valves are the future of high revving, custom timed valve applications. This has been used extensively on Formula one for years now. And, I learned this weekend that they are applying the concept to MotoGP bikes as well. That kinda shocked me, but makes complete sense due to the high rpms.
The reason they work so well is because you can create as high of a pressure as you want, and this directly translates in more opening/closing force, and faster opening and closing times, which is needed in high rpm apps. In the case you site, timing, pneumatic valves also solve the problem.
But, I think the cost is prohibitive, along with the fact that if there is a leak, your engine won't run. Same goes with electric valves, no electricity, no runny.
-Luke
PS - Attached is a pic where the spring is replaced with a pneumatic valve, which I think is what is currently used in F1 and MotoGP, and includes a cam. I think you propose losing the cam, which I do not know of a system where that exists. Maybe it's what is used in F1 and MotoGP, but I can't confirm.
Leon
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Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
...for the owner!!! You're right, that system is quite elegant, but simple. But, I think it's heavier (if you're counting beans). Again, failsafe compared to fluid/gas/electric valves.
If we're pushing our cars/trucks to 300,000 miles, I'd prefer the old system, ultimately!
Everyone has looked at the cam and the spring!
- The amazing Harry Ricardo (Sir Harold of Norton Motorcycle fame) went for 4 carefully positioned valves per cylinder and overhead cam in 1932.
- In about 1950 GM brought out the hydraulic valve lifter to improve cam to valve clearances
- In the early 1950s Mercedes developed the Desmodic valve where two lobes are used, one to open the valve and the other to close it, replacing the spring. This is secret behind the current racing Ducati Motorcycles and some Formula 1 and Indi engines (FAR better than air).
- Dished spring washers were the rage when I was a kid (1970)
But you still have all the limitations of cam, cam drive gear etc etc
It’s time to come up with a solid state breakthrough rather than continuing to perfect the existing cumbersome mechanical system.
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One must always add an altenator, regulation, and a battery. These are really a secondary system that is quite unnecessary for fuel injection to function. And they are prone to independent failures that add an additional layer of maintenance and control to an all mechanical solution. It can be done, but should it be done is another question. These days, jet propulsion engines rely heavily on sensors and electronic control, but I suspect all the failsafe features revert to relying on a purely mechanic mode to protect the engine.
If electronic injection or timing is off, fuel may be ignited at the wrong time and either ignite an open intake manifold or drive a valve through a piston. These things do happen sometimes with mechanical failures during assembly, but once the system is put together right - they don't occur.
Most of these new electronic additions to engines are very much about pollution control tweaking the ignition to an unusual power curve. By eliminating these electronic sub-systems, cam shafts, vacumn sensors, and direct drives do extremely well at producing optimal power for fuel economy without electronics. But not for clean air.
Added to this is the problems of maintaining electrical insulation under oily and hot conditions and I suspect that an piezo-electric injector will have to struggle greatly to gain the loyalty of mechanics and automotive engineers. It must do more than be equal to the mechanical option, it must excell far beyond it.
Still, the automotive industry is always talking about possible new innovations that never come about because they want the buzz to encourge people to consider buying new product. That's why we see all these concept cars at automotive shows and never see them on the street.
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PLEASE CONSIDER the following:
Do you want a quickly operational black box solution or the knowledge included therein?······
Do HEUI's employ pilot shuttle valves?
Thank you, Tom Perkins
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We all make mistakes when we are young………That’s why paste is edible!
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Thank's Brian
·"Imagination is more important than knowledge..." ·· Albert Einstein
www.PropelX.com
www.NorthStarMachining.com
Power steering and power brakes are now electromechanical on some cars.
Transmissions are all becoming electronic, yes even the normal stick shift (I don't think many Americans drive H shift vehicles).
As Bond 007 says “NEVER say never…”
We have a bit of a stupid saying in South Africa. It goes like this.
The world consists of three types of people, those that make things happen, those that watch what’s happening and those that wonder “what the SH#& just happened!!!”.
I think most readers of this blog, yourself included belong to the “make things happen” group so we may want to keep our minds open to opportunities.
Kind regards from Darkest Africa
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Electronic ignition, like the alternator, is an improvement of the electrical systems. Points and generators were really inferior due to heavy wear and tear.
Fuel injectors, valve trains, and carburators have evolved primarily as mechanical devices because they really did the job best. I just don't see how they can easily and suddenly cross over to electronics and be as reliable or improve performance.
On the other hand, fuel cells and lithium batteries are making headway into the automotive to create new modalities of transport. Toyota has heavily committed to hybrids this year by building lithium battery factories and hybrid production lines.
Some lines of innovation are fruitful, but others - many others - end up duds. Mostly because product development always unveils details that are previously unknown or unseen. After all, the Mazda rotary and the Stanley Steamer were once fleetingly thought of as optimal technology; but neither are to be found outside the annals of history.
Admittedly, I may not fully understand the advantages of piezo-electric injector stacks. They may last longer and wear better than mechanical fuel injectors.
But valves are generally opened and closed by a cam shaft that is directly geared to the engines crankshaft. It seems to take a great deal of force to open and close the valves. The cam shaft is as much a major component of the 4 cycle engine as the piston or the crankshaft. It is difficult for me to envision an electronic solution that would hold reliably together under the heat and abuse.
I just feel some things work better with a mechanically driven solution and others work better with an electrically driven. After all, it the timing wander merely a bit off, flames are shooting out the intake and exhaust manifolds or a piston is driven through a valve.
I suspect most of the automotive complexity of today is driven by marketing trying to make cars obsolete due to changes in design. These days, automotive electronics forces use to visit a shop just to turn off an indicator light that may mean nothing.
I'm more interested in real conceptual advancement of generic engineering principles.
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PLEASE CONSIDER the following:
Do you want a quickly operational black box solution or the knowledge included therein?······
Post Edited (Kramer) : 7/7/2008 1:11:02 PM GMT
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We all make mistakes when we are young………That’s why paste is edible!
– You may be right about an imminent change in technology. The reciprocal steam engine went through its biggest changes between 1880 and 1910, when its replacement, Parson’s very simple steam turbine was already gaining popularity.
Will the replacement be electric, Hydrogen, Atkins Cycle engines (or Wankle or something else)?
In the early 1990’s I the amazing good fortune to listen to a talk by the World Bank’s Director on Energy. This Frenchman with the unfortunate name of Dr James Bond made three important points.
1 The world have always paid too little for petrol (gas). He was a renowned economist before he got his World Bank Directorship so he used charts to demonstrate how much the low fuel price in the US were cross-subsidised by the rest of the world. (Before you jump down my throat, he was appointed by the US because he was very supportive of US Multinationals…[noparse];)[/noparse]
2 Electric cars still need power generation. Substantial improvement in storage cells was (and still is) needed before electric cars would be economical.
3 So much research has gone into the petrol engine that it was far ahead of its existing competitors on the development cycle. It is only likely to be replaced by technology that is very different and a lot more efficient than anything we now use.
@ TC
– OOPS sorry guy, its too late. I can’t stop the current manufacturers, particularly in the East. The express train called “drive by wire” is blasting down the tunnel towards us.
I am reminded of my grandfather, a school inspector in rural South Africa who used to travel between country schools in his two horse “Cape-cart” because he could write his reports and do his paperwork while the horses trudged faithfully on to the next school. He seldom covered more than 30 miles in a 9-hour day, which even in those days was under an hour’s drive time in a motor car.
Accepting new ideas often requires a paradigm shift in our thinking. Many commentators, Alan Greenspan being the most recent, suggest that this ability to adapt to new concepts is why the Americans bounce back while other nations particularly the Japanese recover from calamity more slowly.
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What I am interested in is the actual design breakthroughs, like those thermoplastic safety plugs. We have neodium magnets and lithium batteries that are offering to change the fortunes of electric cars by reducing the overall weight.
On the other hand, a fully functional diesel engine doesn't require any electricity if it can be started by other means. Ocean transports uses huge diesels are are very efficent. Electronics merely senses and relays control in such contexts.
Brake-by-wire and drive-by-wire are already realities if you are flying Airbus and Boeing. And tractor-trailer rigs are doing the same, but they need the air power to assist is stopping the large 40ton loads they carry. This is all being done with microprocessor networks like Canbus, from Bosch.
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PLEASE CONSIDER the following:
Do you want a quickly operational black box solution or the knowledge included therein?······
Post Edited (Kramer) : 7/7/2008 6:21:54 PM GMT
Now you’ve hit both of my favourite topics, Reciprocal steam Engines and motor cars. Stanleys and White Steamers were characterised by poor sustained performance. They could accelerate quickly to 20 MPH but literally “ran out of steam”. If you tried to travel at 40 mph for more than a half mile, they died and you had to stop to build up steam. They were much smoother than many petrol (gas) vehicles of the period but VERY heavy on fuel, I think the figure was less than 4 miles per English gallon (say 3.5Mpg US).
My brother was an organiser at an annual motor show and I once got to travel in three pre-1914 cars, a White, a Silver Ghost (RR's last model designed by Royce) and a Crossley. I also had a ride in a later Model T ford though mechanically, it wasn’t much different to the 1913 Tin Lizzy.
The White was running on Power paraffin (Jet Fuel) and it stank. As you know, Stanleys and Whites could run on a variety of different fuels, the owner even used sunflower oil. The quiet roar of the fire was the only noise. There was glorious steam everywhere (quite a road safety hazard because other drivers couldn’t see past the vehicle). It still wasn’t as quiet, as refined or as economical and the Ghost. The Honerable Mr Rolls, the man who sold these cars, used to say of the Ghost, “The quality will be remembered long after the price has been forgotten” and some 25 years after riding in it, I still remember that trip with nostalgia.
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http://rbowes1.11net.com/dbowes/
One thing I haven't seen mentioned yet in this thread is one of the motors GM had in the early 80's. It was their 8-6-4 V8 engine. They would run on all 8 cylinders when extra power was needed but under lighter load would shut down cylinders to conserve fuel. Although the engines had a bad reputation I do know a couple people who had very good luck with them and swore by them (instead of at them) and they got very good mileage for the time compared to a straight V8. A page that talks about it is here:
http://www.mcsmk8.com/8-6-4/8-6-4.HTM
Robert
You were right!!! IH has done some work on this. They must have had some problems because they promised to release it in 2007 and have missed their deadline. The valves aren’t completelysolid state though but electro-hydraulic.
http://eetimes.com/story/OEG20000414S0050
@Robert
Interesting Motor. “I gonna buy me a Cadillac”, well maybe not, our roads are too crowded.
@RC30Fan
hanks for that link
Well you may not be able to buy cars with electronic valves yet but you can buy the ICs to run them from Freescale! Very Interesting…
http://www.freescale.com/webapp/sps/site/application.jsp?nodeId=02Wcbf56hRCrcd
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As we have 3 vehicles in our household - i've started maintaning them myself - they are old ish (1994/1995 N/M plates) so you still can for most stuff. The newer cars are too complex for the amater and require a laptop to diagnose / repair.
What worries me is the complete lack of basic understanding of technology in the world. Physics & sciences not really taught anymore. People in the office - unable to wire a plug (and also not allowed to under the banner of "health and safety")
Still. Imagine servicing that beast (the Audi engine at the top of the thread!) Ouch.
J