Board logo

Really silly engine idea..
akumabito - 20/4/07 at 02:04 PM

I just had a brain-spasm, and I'm sorry for bothering you guys with it..

I was thinking, what if you use two engines, mounted transversely, side by side, connected together by a differential which in turn is connected to a short gearbox, which drives another diff which drives the wheels.

Sortof like this: 

code:
 

ENGINE 1            ENGINE 2 

ENGINE 1-(DIFF)-ENGINE 2 

ENGINE 1    [T]    ENGINE 2 

                   [R] 

                   [A] 

                   [N] 

WHEEL        [S]       WHEEL  

WHEEL----(DIFF)----WHEEL 

WHEEL                    WHEEL


As it was just a brainfart, I haven't actually though about whether or not it is possible to combine the power of two engines through a diff.. I guess it would speed up the input a lot... hmm, the second diff steps it down again, but I guess not enough. Unless you could somehow factor in an additional final ratio...

Oh well.. I guess my 'birlliant' idea failed right away.

Sorry to have wasted your time!

(I bet my ascii art is getting all messed up, too!)

EDIT: Yup, as expected, the ASCII art got screwed up.. oh well.. I hope you can still make out my stupid idea..

[Edited on 20/4/07 by akumabito]

DIY Si - 20/4/07 at 02:13 PM

Only problem is you'd need two 1-1 diffs, which no one makes. I looked into something similar for a 205 T16 (4 x 4, mid engined) type car. The option is chains.

rav - 20/4/07 at 02:15 PM

Is that not similar to what Z-cars (and probably lots of other before them) did with thier twin bike engined tiger?

That had engines in line though, which is probably better cos you wouldn't need to turn the drive through 90 degrees before it goes to the gearbox. Oh and they didn't need a gearbox cos the engines had one each, er so not very similar at all then.

Maybe I should stop putting it off and go and build something....

akumabito - 20/4/07 at 02:30 PM

quote:
Originally posted by DIY Si
Only problem is you'd need two 1-1 diffs, which no one makes. I looked into something similar for a 205 T16 (4 x 4, mid engined) type car. The option is chains.


Why would you need 1:1 diffs? The first diff (unfortunately) speeds up the engine output, the last diff steps it back down again. In essence, wouldn't this be the same as fitting 1:1 ratio diffs? (Well, besides the point that you'd probably destroy most transmissions with such high speeds, lol..)

I guess the biggest problem I see is the final ratio, as with this design, there really isn't one. Don't most cars have a 1:1.2 to 1:1.4-ish final drive ratio?

02GF74 - 20/4/07 at 02:40 PM

hhmmmm, I can't seem to get my brain round this but my reaction is will the prop turn the right way?

i.e. if engine 1 is running and engine 2 is not, prop truns one way but other way if engine 2 is running but engine 1 is stopped.

DavidM - 20/4/07 at 02:48 PM

If the engines are transverse with the flywheels facing each other, they will effectively be rotating in opposite directions. This effectively means no drive from the first diff.

David

akumabito - 20/4/07 at 03:01 PM

D'oh! Can't believe I hadn't thought of that, lol! Hmmm... any (easy) way around that?

Agriv8 - 20/4/07 at 03:46 PM

Asci art that takes me back to my computer room days.

we had a few 164 char impact printers.

We had the naked lady that used to get printed out for special ocasions.

.

Simple days before Viruses and Microshaft ( funny how they turned up just about togeteher !!!! ) Anyway back to payroll running on good ols AIX !!!.

regards

Agriv8

speedyxjs - 20/4/07 at 06:32 PM

quote:
Originally posted by akumabito
D'oh! Can't believe I hadn't thought of that, lol! Hmmm... any (easy) way around that?


Doesn't the honda s2000 spin the opposite direction to most engines? The down side is if it does, you would have to have two different engines. Great idea though

nick205 - 20/4/07 at 07:35 PM

I've been thinking about this too (in a similar vein to DIY Si with the 205 4x4).

My thoughts recently have been on whether you could realistically run without a centre diff (?)

What I'm thinking is to use a front and rear diff (e.g. Sierra XR 4x4 or similar) with a propshaft running the length of the car connecting the inputs of the diffs together (not sure if the rotation direction works out rigtht).

Next up, mount your engine and gearbox (CEC or BEC) North/South in the middle of the car parallel to the propshaft. Then use a chain drive between the gearbox output shaft and the propshaft.

Could this work?

Would the lack of centre diff make it undriveable?

greggors84 - 20/4/07 at 07:52 PM

Im sure the Honda S2000 engine spins the right way, whereas some other Hondas B16, B20 etc spin the wrong way.

I think...

akumabito - 21/4/07 at 05:36 AM

I don't think having two different engines is an option, unless they hav the same RPM range, the same output-per-RPM, etc., etc. if not, the whole thing is kindof pointless as it would just be run by the faster-turning engine...

I'm thinking about a home-made transfer case.. this could also solve the problem of the final ratio.

In essence, it would just be a small, rectangular box. Inside, there would be two gears (salvaged from old transmission?) which give a 1:1.3 overall reduction. This transfer case reverses output direction and give a reduction.

The other engine would get a similar transfer case, only here it would consist of two cogs connected by a chain that would also give an exact 1:1.3 reduction, but not reverse the drive.

One goes on the left engine, the other on the right engine, the engines are connected through the TC's to the diffs, then to the transmission, the other diff and finally the wheels.

I guess that would solve the problems, right? Final ratio and reverse drive on one engine..

CaptainJosh - 21/4/07 at 12:20 PM

http://www.aerotwinmotors.com/

Someone posted this in another thread^ thought it might be of use for an engine idea, you can swap the starter and cams around so you can run the engine in the other direction.

Looks pretty good.


Although it is a plane engine... But as you said, its a silly idea anyway so pretty much all ideas are probably welcome.

[Edited on 21/4/07 by CaptainJosh]

akumabito - 21/4/07 at 12:39 PM

Twin 65Hp engines, now THAT is just plain silly..

kb58 - 21/4/07 at 12:57 PM

quote:
Originally posted by CaptainJosh
http://www.aerotwinmotors.com/

Someone posted this in another thread^ thought it might be of use for an engine idea, you can swap the starter and cams around so you can run the engine in the other direction.
[Edited on 21/4/07 by CaptainJosh]


And oil pump!

kb58 - 21/4/07 at 01:01 PM

quote:
Originally posted by akumabito
I don't think having two different engines is an option, unless they hav the same RPM range, the same output-per-RPM, etc., etc. if not, the whole thing is kindof pointless as it would just be run by the faster-turning engine...


No, it really would work. Both engines add their share. Think of them both being in neutral, running at, oh, 3000rpm. Let the clutch out on the first engine, and the car will go some speed, with the first engine slowing down to perhaps 2000rpm. Now let the clutch out on the second. It does in fact add its share of "effort" to the mix.

As counter-intuitive as it sounds, you can have a 200hp engine and a 5hp engine to a common shaft, and it really does put out 205hp.

One other way to think of it is by fuel consumption (energy in). The work of both has to go somewhere.

akumabito - 21/4/07 at 01:17 PM

There's no way an engine could run in reverse direction, right?

Doug68 - 21/4/07 at 01:58 PM

How about this?

Have your 2 chosen engines face for aft in the normal fashion. Then fabricate a primary drive case like those on old motorcycles or (cough) Harley (cough) Davidson's (vomit). The two engines are joined by a wide continuous belt or duplex chain that drives the output shaft in the middle which has the clutch mounted on it.

Go this way and there's only one diff and relatively normal gearbox required. But there is a bespoke primary drive to make.

It would make a fairly wide car though. I'm sure that this has been done before for some movies at least.

akumabito - 21/4/07 at 02:11 PM

Well, as the thread title suggested, it was a silly idea to bein with, so don't worry about it not being entirely realistic.

Hmm... they should do some more Mad Max type movies.. I'm sure we could all chip in some bizarre ideas...

kb58 - 21/4/07 at 03:15 PM

quote:
Originally posted by akumabito
There's no way an engine could run in reverse direction, right?


Sure it can, and it has been done, but it's a bit of a pain, plus the expense of getting it done.

[Edited on 4/21/07 by kb58]

Simon - 23/4/07 at 11:46 PM

Wolfrace did the twin engine thing nearly 30 years ago with the Sonic (http://www.supercarworld.com/cgi-bin/prototypes.cgi?startfrom=61&sortby=atoz) - 2nd one down.

Engine will run any way you like (you have two choices) so long as cam(s) opens/closes valves in right order, the mix goes bang at the right time and your oil is pumped.

Is this the kind of thing you have in mind:



ATB

Simon

[Edited on 23/4/07 by Simon]