spec needed

[beastfromeast]

Hi everyone. I'm studying in mechanical engeneering and I'm doing a project at school about engines. Is it possible for somebody to give me some infos that could help me on my project. I need informations sbout pistons, connecting rods and crankshaft. Also, if you have infos on anything else like turbos, superchargers or other mechanical parts, please email me : Raph_sicard@hotmail.com

Thank you very much, I will reply to any post.

Raph...

[jimmyfunk]

your question is WAY to broad...I wouldn't even know where to begin. You're going to have to be a little more specific. What exactly do you want to know?

[b16b bomber]

go to this site: http://www.howstuffworks.com
it should answer alot of your questions

[beastfromeast]

Thanks guys, but I speak to my project director and he told me that it wasn't really what he was asking me. So I choose to built a brand new type of engine, because anyone who study in mechanical engeneering know that our type of engine is a big mistake in mechanic. So I start to think of new kind of engine.

If anyone have an idea, I'm WIDE open, even if my idea is almost fixed. Thanks again, you're a lovely bunch of buddies.

Peace y'all, Raph...

[b16a3sol]

i dont you even know what you are talking about anymore beast.

[fritz_269]

Originally posted by beastfromeast
So I choose to built a brand new type of engine, because anyone who study in mechanical engeneering know that our type of engine is a big mistake in mechanic.

And exactly why is that? I think the internal combustion engine is a pretty darn good way to get mechanical energy. They're somewhere around 35% efficient, and the energy density of fossil fuels is fantastic (i.e. you can go a long way on a small tank). Where is the "big mistake"???

I think maybe the only other reasonable (though not yet fully developed) technology is inertial energy storage running electric motors. It has the potential to be vastly more efficient; but the flywheels are just too expensive, too unsafe, and still don't quite have the energy density needed for a modern automobile.

[beastfromeast]

What I meant by a mistake is not that internal combustion engines are not efficient, I mean that the type of power transmission is very not the best if you analyse it this way: the up and down displacement of the pistons is create by the explosion. The explosion is like a Force apply vertically on the piston, but when the connecting rods pushes the crankshaft, it apply the Force of the piston with an angle tangeant to the rotation of the crankshaft. In other words, you lost a lot of energy to transfer a lateral (or vertical) displacement into a rotary movement.

That's why I think that those type of engines are mechanically not the best engines, that we could designed more direct power transmission engines.

If you don't agree, reply me, we'll talk again, I love this stuff.

Peace y'all, Raph...

[fritz_269]

Originally posted by beastfromeast
...In other words, you lost a lot of energy to transfer a lateral (or vertical) displacement into a rotary movement.

Perhaps you should check your physics book on that one. Energy is conserved, no energy is lost in any direct mechanical linkage (except through heat from friction). The main loss of energy (inefficiency) comes from the loss of heat. The the heat in the gas that is expanding to push against the piston bleeds off through the cylinder block, heads, piston, and oil - meaning that there is less heat energy in the gas to expand against the piston.

So why don't we just insulate the cylinder better to keep the heat inside? Because it has to be cool enough not to detonate the next incoming air/fuel mixture. So we end up having to make a compromise. This is the exact reason that engines specifically built for high octane gasoline can make more power - they can hold more heat in the combustion chamber without detonation on the next stroke.

That's why I think that those type of engines are mechanically not the best engines, that we could designed more direct power transmission engines.

Again, there is no energy lost in the mechanical linkage (except friction). But you might be interested in the Wankel engine if you haven't seen one before, it has a different type of linkage.
http://www.automotiveforums.com/vbulletin/t25814.html

You might also be interested in the Stirling engine. This is a heat engine with a theoretical efficiency of 100% (and it uses pistons & crankshafts).
http://www.howstuffworks.com/stirling-engine.htm

[beastfromeast]

Thanks Fritz, I appreciate your comment. I have to admit that u're right about the lose of energy that is created only by the heat reaction, as u say, I check my physic books, or rather in my dynamic and material strengh books. But whatever, when u take a step back, u have to admit on your side that it's not the ideal engine design.

By the way, thank you for the links, especially the how stuff works one, it's very interesting, as much as this thread instead of many useless thread on AF.

Peace y'all, Raph...

[fritz_269]

Originally posted by beastfromeast
....But whatever, when u take a step back, u have to admit on your side that it's not the ideal engine design...

Sure it has its problems, but at the moment, nobody has come up with anything better overall. If you do, please let us know!

In all honesty, the Otto-cycle and Miller-cycle engines are pretty darn good at what they do; particularly with modern technology in materials, design, and computer control.

[beastfromeast]

You got me there, I have NO idea what's an Otto-cycle and a Miller-cycle is. I'm curious what is it? You seem to know a lots of things in automobile mechanic. I like it.

Peace y'all, Raph...

[fritz_269]

Originally posted by beastfromeast
You got me there, I have NO idea what's an Otto-cycle and a Miller-cycle is. I'm curious what is it?

Go back to www.howstuffworks.com!

Otto cycle - typical four stroke engine -
http://www.howstuffworks.com/engine1.htm

Miller cycle - more efficient four stroke w/ forced induction -
http://www.howstuffworks.com/question132.htm

[Someguy]

Here's a couple links by way of Texan which may be interesting for your project:

http://www.sciam.com/1097issue/1097rosenbox2.html
http://www.awl.com/englishpages/tech...g_hardware.htm

Also look into turbine engines. They solve the problem of the pistons having to move through their stroke 4 times for every power stroke they make, while not having some of the limitations of 2-stroke engines as described by howstuffworks, but add a whole new set of limitations. Look into the M1 Abrams family of tanks for a real life example.