Its still a lot of wear. Ducatti still has trouble getting it to last past 50,000km.Originally Posted by jediali
Its still a lot of wear. Ducatti still has trouble getting it to last past 50,000km.Originally Posted by jediali
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The problem with them is that they have to run at VERY exact clearances, and so need quite regular servicing, and aparently at 60,000km, they have a major service on the Desmo system that basically involves replacing a lot of the sysetm. However, they are continuously working on it to make it less and less sensitive and increasing the service intervals.Originally Posted by jediali
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There is still the increased mass that will hurt acceleration and because of the lower leverage when the cams press the air springs there is a significant (probably larger than the amount lowered from bearing friction) increase in friction. Also trying to fit gears or pulleys that can get the 4:1 ratio on a DOHC head will be twice as difficult as trying to fit the normal gears or pulleys. I have never heard nor seen anything that even hints that F1 engines have double lobed cams and I have heard and seen lots that shows them having normal single lobe cams.Originally Posted by stian1979
Good idea with thinking about desmodronic systems they are great for valve activation but as you have heard they have high wear and tear. Are you considering air springs for the valves? like current F1 cars use.
Power, whether measured as HP, PS, or KW is what accelerates cars and gets it up to top speed. Power also determines how far you take a wall when you hit it
Engine torque is an illusion.
don't air springs need a lot of attention too?Originally Posted by hightower99
autozine.org
Hey JediAli, I'm looking at switching from MiningEng. to Autoeng. next year, what are you enrolled in?
I graduated this July form a degree of Masters of mechanical engineering (+diploma in management). Aberdeen university is primarily an oil/gas type faculty so there is no automotive option, otherwise i would have took it.Originally Posted by P4g4nite
autozine.org
Air springs is crap.Originally Posted by jediali
If the seal fail the spring fail.
It is used on large two stroke diesels but there you can have a compresor that make shure you at all times have enough air to replace the one that leak out. and they nead to be overhauled all the time because off the bad fuel they runn on so replacing the seal at the same time is not a real problem.
F1 engines don't nead to last forever and sometime they refill air on pit stops. MS a few years ago I remember.
For street car's it has no real world relevance since it is going to runn for maybe 10 years and 200 000km
Air springs aren't crap they can make sure that there is absolutely no valve float at all up to 19 000 rpm.Originally Posted by stian1979
F1 current airspring systems use an airpressure bleed from the cylinders and therefore don't need to be filled up with air. I haven't heard of the airvalve system failing on a F1 car in the last 7-8 years... F1 engines are also designed to basically only last one race. If you built the airspring system into a more mundane engine you could easily have it last for a good long while.
On a high revving V10 it would be a great idea as it is lighter, self adjusting, and ensures no valve float to whatever you want your redline to be.
Jediali: With current automotive computer control it is possible to make a totally self-adjusting system, and it is possible to make an air-spring system that will last for a long time (obviously it will need an overhaul at some point)
What are the basic design parameters that you are considering to at least make a CAD drawing of...?
Power, whether measured as HP, PS, or KW is what accelerates cars and gets it up to top speed. Power also determines how far you take a wall when you hit it
Engine torque is an illusion.
Wouldn't airsprings be a vital part of the newer valve actuation systems that do away with cams and use electrohydraulic systems instead?
precision air valves or mahnetic solenoid actuators could arrange the timing but i'd hate to be the engineer trying that one out, seems like the way forward though.Originally Posted by 2ndclasscitizen
autozine.org
Returning to the valve phasing interesting idea, I just found in the Matt's hideout a high res BMW Vanos diagram of the E46 M3. It's very similar to your design, so you can pick some ideas for improvements...think that this design actualy is running on a real performance car
Also there are many M3 technical pics and diagrams that may interest you in the same thread, I hope you enjoy them as I do, I really like this kind of stuff.
http://www.ultimatecarpage.com/forum...2&highlight=m3
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thanks very much. ace engine pics there - its like bender and his circuit diagrams!
we sort of said a cylinder inside a cylinder is the way to go for phasing and thats what i will do! Tell you what, once i sort the engine out into a final proposition i might license it to the ucp supercarII
autozine.org
I am aware of a few things to be done on this model and i decided to start again. This time a simpler engine with more detail to reflect more functional dimensions. I think I am about 1/3 of the way there, now working on cylinder heads, ancilaries and intake/exhaust. I still think the block is the most time consuming but its pretty much done.
A few tasters:
autozine.org
hmm, have you calculated the forces on the piston walls with the crank and v angles ?
Those look VERY thin walls .... and not a lot of support in the base of the V either. Can't see how you'll stop that twisting and having nasty harmonics capable of shaking the engine to destruction.
Don't see you casting that block like that. Planning to machine it or to use wet liners ?
If machining are you workign within cutting tolerances ?
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Just out of curiosity....is this program available for free anywhere? I know a lot of software groups give out the old versions for free.
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