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does this exist?
does this exist? I was just thinking about how to make an engine more efficient and effectively put that power to the ground. Something may already exist, im not sure, but its definitely something Ive been thinking about!
First off the transmission would have to be continuously variable (CVT), so the engine would always be in its power band. Next the engine would have to have some sort of forced induction so it would be more efficient.
I was mainly thinking about the valve train. I know Variable valve timing exists, but what about eliminating the camshaft(s) all together? Why cant you just have all of the valves controlled directly by solenoids? It doesn't seem that far-fetched to me. Has this been thought of before? Any reason it wouldnt work? - V
First off the transmission would have to be continuously variable (CVT), so the engine would always be in its power band. Next the engine would have to have some sort of forced induction so it would be more efficient.
I was mainly thinking about the valve train. I know Variable valve timing exists, but what about eliminating the camshaft(s) all together? Why cant you just have all of the valves controlled directly by solenoids? It doesn't seem that far-fetched to me. Has this been thought of before? Any reason it wouldnt work? - V
Last edited by IamSam; Jul 4, 2011 at 03:38 AM.
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From: Australia
i think some F1 teams use air actuated valves off an air compressor this give you a million different durations lift everything for you to play with you can get some camshafts that have good bottom end good mid range bad top end.
and cams that have good mid good top and bad bottom, with air valves it is good all over.
and cams that have good mid good top and bad bottom, with air valves it is good all over.
BMW uses solenoids in some engines to control valve events but they are only capable of doing like 5k RPM. Some companies like Toyota control intake valves by means other than camshaft to control compression and improve efficiency at different times.
Lots of interesting things going on behind closed doors in the auto industry right now. Yes, camless engines. cams with two lobes per valve. Of course the direct injection.
That's damn impressive that they're good to 5K. I looked into this a while back and finding a solenoid capable of handling ~54 Hz @ 6500 RPM that can also handle the environment is a tall order.
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TECH Enthusiast
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If you want to see something different in valve train, look at Ducati's Desmo system - no valve springs.
A solenoid might have issues moving valves quick enough without overheating at highe engine speeds. One cannot instantly open or close a valve that has mass - you have laws of physics that are hard to get around. Split lobe cams that allow changes in duration are an interesting concept, I believe Porsche tried this a few years back.
A solenoid might have issues moving valves quick enough without overheating at highe engine speeds. One cannot instantly open or close a valve that has mass - you have laws of physics that are hard to get around. Split lobe cams that allow changes in duration are an interesting concept, I believe Porsche tried this a few years back.
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Launching!
Joined: Aug 2006
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From: Lewisville, TX
[/QUOTE] Split lobe cams that allow changes in duration are an interesting concept, I believe Porsche tried this a few years back.[/QUOTE]
sounds like honda's vtec to me, a more aggressive lobe design that's actuated over a certain RPM for a broader powerband. and we all know that's been around for over 20 years.
then BMW has a system that can actually change valve lift throughout the RPM range instead of like the vtec on/off switch but duration remains relatively the same, i believe
sounds like honda's vtec to me, a more aggressive lobe design that's actuated over a certain RPM for a broader powerband. and we all know that's been around for over 20 years.
then BMW has a system that can actually change valve lift throughout the RPM range instead of like the vtec on/off switch but duration remains relatively the same, i believe
ducati's desmo valve system is nice, although a bit finicky on adjustments and can cost alot of money if its not set up correctly. openers, closers, shims and cams cost ALOT of money, even for a bike with 8 valves.
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I was just thinking about how to make an engine more efficient and effectively put that power to the ground. Something may already exist, im not sure, but its definitely something Ive been thinking about!
First off the transmission would have to be continuously variable (CVT), so the engine would always be in its power band. Next the engine would have to have some sort of forced induction so it would be more efficient.
I was mainly thinking about the valve train. I know Variable valve timing exists, but what about eliminating the camshaft(s) all together? Why cant you just have all of the valves controlled directly by solenoids? It doesn't seem that far-fetched to me. Has this been thought of before? Any reason it wouldnt work? - V
First off the transmission would have to be continuously variable (CVT), so the engine would always be in its power band. Next the engine would have to have some sort of forced induction so it would be more efficient.
I was mainly thinking about the valve train. I know Variable valve timing exists, but what about eliminating the camshaft(s) all together? Why cant you just have all of the valves controlled directly by solenoids? It doesn't seem that far-fetched to me. Has this been thought of before? Any reason it wouldnt work? - V
I think it was the Williams F1 team that used a form of CVT transmition in F1, right before it was band for being TOO effective! So it dose work. lol Basically the idea is you can hold the engine at a constant rpm to devilver the most power. In a really world senario as you accelerate the engine would automaticely blip to peak power rpm and you would accelerate away. Then once the required spped was reached the engines RPM would fall away but maintain a contact road speed. Big engines would not be needed as much smaller unit could provide the power required ofor short periods during acceleration. Also oyu wouldn't need the broad exspance of torque as the engine would hold a fixed RPM while accelerating. Plus the engines could be designed to work most effectively at fixed engine speeds (a bit like aero piston engines).
F1 has and still dose use pneumatic valve springs. This effectilve means you can run MUCH harder acceleration on the cams than you can with a spring. role on greater cylinder filling and thus more power.
Lotus has done a lot of testing on electronic valves and variable comp. ratio engines. nothing really come to life on these though.
CHris.
Siemens has also been working on some solenoids for doing this. The hard part is initial start up timing and long term reliability. There is a lot of heat in a small space and alot of repetitive wear surfaces.
there's an Alfa Romeo production car with a primitive version of this... Google the Alfa Romeo MiTo Multiair.
Camless has been sort a holy grail for a while... I mean, PERFECT valve lift and duration for EVERY combustion event is CRAZY... The torque curve on an LS1, for example, would look INSANE. And then you get into the tuning aspects of it. If the system was run off of tables in the PCM, you could do all sorts of crazy things like change lift and duration for load and throttle percentage, as well as RPM. With a properly engineered and tuned setup, you could have a street/strip MONSTER that could get 35-40mpg on the ride home. All with no idling problems.
Camless has been sort a holy grail for a while... I mean, PERFECT valve lift and duration for EVERY combustion event is CRAZY... The torque curve on an LS1, for example, would look INSANE. And then you get into the tuning aspects of it. If the system was run off of tables in the PCM, you could do all sorts of crazy things like change lift and duration for load and throttle percentage, as well as RPM. With a properly engineered and tuned setup, you could have a street/strip MONSTER that could get 35-40mpg on the ride home. All with no idling problems.
There is a continuously variable desmodromic design too. I don't remember the exact name but the throttle cable went to the valvetrain and it has no throttle body. It changes duration and lift in accordance to throttle input.
Sturman Industries is a real heavy hitter in the camless engine world. Their Digital Hydraulic valve actuation looks promising:
http://www.sturmanindustries.com/mai...eActuation.htm
http://www.sturmanindustries.com/mai...eActuation.htm
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Isn't something similar fitted to some BMW engines?.....
Or you could get rid of the poppet valve altogether and use this...
http://www.coatesengine.com/
This is awesome because you dont have a mass going up and down. Also the valve doesnt protrude into the chamber so PTV clearance isnt an issue.
http://www.coatesengine.com/
This is awesome because you dont have a mass going up and down. Also the valve doesnt protrude into the chamber so PTV clearance isnt an issue.
TECH Addict
Joined: Aug 2004
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Or you could get rid of the poppet valve altogether and use this...
http://www.coatesengine.com/
This is awesome because you dont have a mass going up and down. Also the valve doesnt protrude into the chamber so PTV clearance isnt an issue.
http://www.coatesengine.com/
This is awesome because you dont have a mass going up and down. Also the valve doesnt protrude into the chamber so PTV clearance isnt an issue.
FormerVendor
Joined: Jul 2008
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Most Nissan Vehicles have a CVT instead of a 5 or 6 speed auto these days. My best friend worked at Nissan HQ and I got to try out the prototype a few years back. Pretty wild watching the rpms stay pegged at 6K.
http://www.nissan-global.com/EN/TECH...RVIEW/cvt.html
http://www.nissan-global.com/EN/TECH...RVIEW/cvt.html