[QUOTE=henk4]yes, 5.5 litre is enough, and the engine is already there....[/QUOTE]
PSA and Diesel... this must be heaven for you... ;)
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[QUOTE=henk4]yes, 5.5 litre is enough, and the engine is already there....[/QUOTE]
PSA and Diesel... this must be heaven for you... ;)
[QUOTE=Ferrer]PSA and Diesel... this must be heaven for you... ;)[/QUOTE]
not only for me...
[QUOTE=Ferrer]PSA and Diesel... this must be heaven for you... ;)[/QUOTE]
psa fanboy (haha. kidding. please dont ban me)
in all seriousness i applied to work for for PSA and they didnt like me because i couldnt speak french. I also applied to delphi and Ford in that respect but they didn't like my degree sylabus:(
So no comments what-so-ever about my two variable compression ideas?
So everyone thinks they are perfect?
I guess I will have to keep thinking about both. That and the idea of combining both to half the travel distance of each solution.
So Jediali: When are you going to post some pic/sketches of your valve control design? I need something to help me picture it. Will it be able to control the lift enough to throttle the engine?
Right I agree that dimensions like bore/stroke, total displacement and the like are to be decided later but that shouldn't stop us from thinking about the systems that are going to be a part of the engine. We know that the engine will be biggish and that it will be a V or W configuration.
Hey Lets talk configuration for a minute:
I for one am hooked on W12 configuration. Using two banks of cylinders arranged like a VR6 it wouldn't be much longer than an inline 4 (shorter than an inline 5) but it would be taller and sowhat wider than a V12. Mass is more centralised in a W12. My ideas for VC work on either configuration.
Jediali: Do you think your valve control could be made to work like the DOHC system currently employed in VR engines? i.e can you get the cams to control a set of valves underneth themselves and off to the side?
I vote W configuration (whether it be a W8, W12, or W16)
[QUOTE=hightower99]So no comments what-so-ever about my two variable compression ideas?
So everyone thinks they are perfect?
I guess I will have to keep thinking about both. That and the idea of combining both to half the travel distance of each solution.
So Jediali: When are you going to post some pic/sketches of your valve control design? I need something to help me picture it. Will it be able to control the lift enough to throttle the engine?
Right I agree that dimensions like bore/stroke, total displacement and the like are to be decided later but that shouldn't stop us from thinking about the systems that are going to be a part of the engine. We know that the engine will be biggish and that it will be a V or W configuration.
Hey Lets talk configuration for a minute:
I for one am hooked on W12 configuration. Using two banks of cylinders arranged like a VR6 it wouldn't be much longer than an inline 4 (shorter than an inline 5) but it would be taller and sowhat wider than a V12. Mass is more centralised in a W12. My ideas for VC work on either configuration.
Jediali: Do you think your valve control could be made to work like the DOHC system currently employed in VR engines? i.e can you get the cams to control a set of valves underneth themselves and off to the side?
I vote W configuration (whether it be a W8, W12, or W16)[/QUOTE]
why do I see no W-configuration in any racing engine?
Do you take it for granted that the engine should run on gasoline?
[QUOTE=henk4]why do I see no W-configuration in any racing engine?
Do you take it for granted that the engine should run on gasoline?[/QUOTE]
Look at what the W engines are in: the fastest supercars and some of the most powerfull luxury cars. I would think that you don't see them in racing because cooling can be a problem as well as the fact that they have to have thin connecting rods. The main advantages of the W configuration is almost a moot point for racing.
But when you want to stuff more engine into a GT that might end up being Mid-engined then you need to make the thing more compact.
We haven't taken it for granted to run on gasoline. We have decided that we are going to design a gas burning engine with some exciting technology that will increase efficiency and produce a better power curve. So far we are thinking of running it as a DICI engine. We are also going to incorperate learn-burn technology into it.
Aren't W engines only used by VAG?
I am pretty sure they still hold the rights on VR and W style engines that are based on VR design.
[QUOTE=Matra et Alpine]See Alpine A610 :)
( OK technically rear engine .... but a 50/50 weight distribution :) )
Put the RX8 doors on an A610 ---- 4 seat, 4 door, performance GT[/QUOTE]
I didn't know that they got anywhere near 50/50 distribution with the big engine hanging off the back and not much up front...?
But I think it would be a really ugly mishap if someone put suicide back doors on it.
Still a good car to take after what with the world record making low drag (0.28 right?) but methinks we are aiming for something abit more powerfull, abit more exotic.
Also: I think we should decide if we are going for FI or NA...
I vote for FI because turboes will increase efficiency and I have always wanted to design a pulse intake for a FI engine.
[QUOTE=hightower99]I am pretty sure they still hold the rights on VR and W style engines that are based on VR design.
[/QUOTE]
they go back to history and study some of the engine designs made by the Lancia factory and you will see that a copyright is hardly applicable...
well that is interesting info...
[QUOTE=hightower99]
Also: I think we should decide if we are going for FI or NA...
I vote for FI because turboes will increase efficiency and I have always wanted to design a pulse intake for a FI engine.[/QUOTE]
In my opinion it has to be naturally aspirated all the way.
the sound, the delivery, no turbo/super charger can match it
FI = sledgehammer
NA = scalpel
[QUOTE=derekthetree]In my opinion it has to be naturally aspirated all the way.
the sound, the delivery, no turbo/super charger can match it
FI = sledgehammer
NA = scalpel[/QUOTE]
FI would allow us to have a much smaller engine in terms of displacement, which would make it more compact.
[QUOTE=Ferrer]FI would allow us to have a much smaller engine in terms of displacement, which would make it more compact.[/QUOTE]
let's use the Radical V8 then, 2.6 litres...
[QUOTE=hightower99]I am working on two ideas.
One: Similar to Saab's idea only because we will be designing either a V or W12 it doesn't seem smart to have the massive cylinders and heads moving around arcing in relation to the crankcase. Instead I am thinking of a worm gear mechanism (pretty simple one really) that will push the cylinders and heads out or pull them closer. That way we will only need a flexible connection to the intake and two simple sliding joints in the exhaust (one each side) and of course the cam chains will run with some extra chain with the slack taken up by a single tension gear for each bank of cylinders. relatively simple the only problem being that how the hell do I cool the exposed cylinder wall when it is fully extended? I figure I will have to lift the water jacket with the cylinders instead of just the liners.
Two: More complicated. The pistons have a cylinder hole in the middle and a metal cup with its bottom completing the pistons face. The cup can be raised or lowered by pumping oil underneth it. The oil would come from a high pressure line built into the engine. More problems, sealing the cup to stop by-products of combustion from contaminating the oil, chance for increased reciprocating weight, Also I am not entirely sure that the suction of the oil chamber is enough to hold the cup in the piston when the piston stops at TDC. Also changing the shape of the piston will complicate the swirl dynamics that we want to achieve to help DI detonation mode combustion. On the other hand it should be a lighter solution in total, it will also get rid of the need to have moving links in the exhaust, intake, and slack in the cam chains. I could also make the cup have a hollow in it to help keep some more heat in the combustion chamber instead of flowing through the piston, that is if it doesn't weaken the cup enough that it fails suring the pressure of combustion.
Actually when I think about it I could make the entire piston face into a cup that fits over the piston "body"... solving some of the problems with changing the face shape... Still have to seal it properly....[/QUOTE]
Its good you can see the flaws in these suggestions and i think they are just too complicated. Great imagination though. helps me think too:). For #1 you never considered the effect on the timing chain/belt. No 2 seems a little comlicated but will help you understrand how my valve lift idea works. The small spring (blue one) is in a sealed oil/air filled resevoir and as a diaphram (serving all intake or exhaust valves) connected to this resevoir by a pipe is moved back or forth the oil volume inside the resevoir changes meaning the cam lobes either compress the free air in the resevoir and then cause valve lift (low lift ) or move the valve as if the blue spring didn't exist (full lift). The red parts follow the cam lobes. Of course there are 1 or 2 minor flaws. This engine model is 3 years old and i know the details are innacurate but this is an old picture, only showing ideas not final models by any means. Over and out:rolleyes:
[QUOTE=jediali]Its good you can see the flaws in these suggestions and i think they are just too complicated. Great imagination though. helps me think too:). For #1 you never considered the effect on the timing chain/belt. No 2 seems a little comlicated but will help you understrand how my valve lift idea works. The small spring (blue one) is in a sealed oil/air filled resevoir and as a diaphram (serving all intake or exhaust valves) connected to this resevoir by a pipe is moved back or forth the oil volume inside the resevoir changes meaning the cam lobes either compress the free air in the resevoir and then cause valve lift (low lift ) or move the valve as if the blue spring didn't exist (full lift). The red parts follow the cam lobes. Of course there are 1 or 2 minor flaws. This engine model is 3 years old and i know the details are innacurate but this is an old picture, only showing ideas not final models by any means. Over and out:rolleyes:[/QUOTE]
VC idea 1: I am not sure what you mean I have considered what happens when the cam gears are further away or closer to the crankshaft. The main problem is how to maintain a set distance in three locations, from crank to first cam gear, between the two cam gears, and lastly between the last cam gear and the crank. As long as the length of chain is maintained in those areas then the timing isn't affected at all by being closer or farther from the crankshaft. I made a mistake I meant to say that two tension gears are needed per pair of cam gears. Basically extra slack is run between the crank and the first and last cam gear. When the system is set for high compression (i.e. the cam gears are close to the crank) then the tension gear have to take up all the slack. As the head moves up and the cam gears travel further from the crank then the tension gears take up less slack and the timing is unchanged.
VC idea 2: Yes it sounds complicated but I have already simplified the total system somewhat. I plan on the top faces of the pistons being the cup that fits over the piston body which is directly connected to the connecting rod conventionaly. I have tried to minimise the volume of oil needed to move the piston face without reducing the working surface area too much. I have also been thinking of combining both systems because this will allow me to half the distance traveled by both systems and therefore make the total solution more realiable, efficient, safer, and possibly lighter. I am looking at an operating range stretching from 16:1 down to 9:1 compression ratio.
Jediali: I do like your system. I hope that as you refine it you strive to make it as light as possible (judging from the pictures they look really heavy) Also wouldn't it be great if we could control intake and exhaust lift seperatly? and what about being able to control the lift of each intake valve in relation to each other (i.e. in one cylinder one of the two intake valves opens with medium lift but the other only lifts abit), this would help achieve the swirl we will need to get good combustion with lean fueling. I hope that you can get a good operating range (I was thinking from 0mm to something like 10-12mm). I can't wait to see what you get once you have refined it. I think you might want to consider where the air is going to go if you try filling the whole thing with oil to get max lift.