5 stroke engine

[gg89220]

hello
distributor interrupter ignition and valve cams

 

[gg89220]

hello
here is the finished engine

 

[awake]

Very nice! Do you have a video of it running?

 

[LSEW]

In the years leading up tp 1888, a French engine builder, Fernand Forest, resarched and
built a similar engine. It was a standard 4 cylinder, but with a 5'th larger cylinder
for exhaust expansion.It was ported so the exhaust from one of each of the cylinders
would enter the expansion cylinder, either on top or bottom of the piston, for each 180
deg. stroke.Porting also allowed exhaust to exit from the other side of the piston from
the expansion cylinder on the same stroke.Thus each stroke had an expansion cycle and
an exhaust cycle from the expansion cylinder.

It is speculated that the idea was borrowed from the triple expansion steam engine.
Unfortunately the expansion of steam and gas from combustion are very different. So it seems from the disappearance of this type IC engine cycle, it was a bad idea. The engine was built by Fernand Forest and his partner George Gallice in 1888 according to an entry in book 2 of the C.H. Wendle series. There is also a wonderful picture of an etching of this engine There.

Very nice work on the model, I hope it runs well, waiting for the video

maury

 

[gg89220]

hello
here is the video

 

[Steamchick]

JUST MAGIC! Well done Sir!
It idles better than my V50 Moto Guzzi.... You have made a smashing model.
Just one small detail, before it wears out, how is the lubrication managed? No sign of oil splash anywhere. How so?
Do the bearings stay cool enough because it is all in the open air?
Also, I know that air cooled motorcycles with in-line twins could overheat the rear cylinder... furthest from the draught of fresh cool air. (Longitudinal crankshaft for convenience for shaft drive as with the Sunbeam twins).
Do you have any way of knowing if the expansion cylinder is able to do any work? E.g. by pressure and temperature measurements of the gases into and out of the centre cylinder? Or pressure measurements within the cylinder? It would probably need a high speed pressure transducer and data capture to gather that info to really understand if it is useful.
Again - well done!
K

 

[Peter Twissell]

An easier way to assess the value of the middle cylinder would be to run the engine with the two short link manifolds removed.
If it can drive a moderate load (e.g. a prop) at a measured RPM and a known throttle setting, then compare RPM with the manifolds replaced.
If a suitable RPM meter (e.g. optical type) is not available, just record the sound for comparison.

 

[Cogsy]

An easier way to assess the value of the middle cylinder would be to run the engine with the two short link manifolds removed.
If it can drive a moderate load (e.g. a prop) at a measured RPM and a known throttle setting, then compare RPM with the manifolds replaced.
If a suitable RPM meter (e.g. optical type) is not available, just record the sound for comparison.

I'm not sure about this method. Exhaust tuning can have a lot of impact on power production so changing the exhaust so much by removing the manifolds might make a lot of difference to power output and might not show the true effect of the middle cylinder. I'm certainly curious about how much power it's salvaging also.

 

[Peter Twissell]

I agree that changing the exhaust will change the engines performance. In this case, the middle cylinder is the exhaust tuning and that is exactly what we are interested in.

 

[coulsea]

If an engine design was economically efficient you would be able to go out and buy one. This one is a huge success because you found a design that interested you and built one that runs, with a great background story for interested viewers. I am always amazed at the endless possibilities of this hobby. keep up the good work.

 

[Steamchick]

Stupid me. A simple comparison using a propeller - must get a propeller! I estimate relative performance of different steam engines by comparing speed against a constant load. (Bicycle Dynamo). But I like the theory as well as the top models and simple toys. I am interested to know how much difference the extra cylinder makes, however that is determined. The Institute of Model Engineering does conduct engine testing on dynos, and temperature and pressure recording , from what I have read, but few individual model makers do that. Yet, to me at least , it seems a natural development of the hobby. And while this thread is meant to be about "model engine machining" I have been an engineer for too long just to focus on machining the bits. One of my "round-tuit" notions is to make a dyno... does anyone have plans? (2 spring balances and a leather belt on a pulley?).

 

[awake]

Beautiful! Sounds great!

 

[coulsea]

One of my "round-tuit" notions is to make a dyno... does anyone have plans? (2 spring balances and a leather belt on a pulley?).

google Prony brake, it would seem to be a fairly easy way to measure horsepower, I think that there may be posts on this forum somewhere.

 

[Canyonman]

Hello Maybe I missed it but are there plans available? Thanks Ken

 

[gg89220]

hello
I made the engine without a plan

 

[NapierDeltic]

Hi gg89220.
I very much appreciate your project. I think you are only at the middle of it. There's no doubt that an IC linked with a compressor will work, especially if mechanical chain is reduced to a minimum. Please go further!
I know you want to prove yourself something and I'm preety sure we are some who would like to see this proof (I mean we are interested in technical aspect and we also appreciate your personal /emotional involvement in it).
In my honest (and modest) opinion you should increase valves diameter. As small as they are now they are strangling the IC side and maybe also the central cylinder. I think the power recovered by third piston has to be quite less compared to the others and gas flow efficiency affects this smaller percentage. Every effort to use otherwise wasted energy is worthed. If efficency testing you intend -and we wait -will show 1.00 per cent gain you'll hear a lot of "told you it's meaningless"! I think modifications are not that substantial and I have seen a lot of skill in your already built parts.

 

[Steamchick]

hello
here is the video

Just watched it again... Made me smile - again! I had a thought about checking to see what effect the middle cylinder has....? Maybe if you removed the exhaust valve push-rods from the middle cylinder, then wedged the exhaust valves of the middle cylinder so they are fixed open, and then checked the speed at the throttle setting for a known speed when "as designed". If using something like an aero-prop as engine load while doing this, especially if you record the comparison on video and analyse the enginer speed, then you should be able to get a reasonable estimate of the increase of efficiency when the centre cylinder has exhaust valves operating. Speed versus aero-prop is a simple square function. (Air-drag is proportional to the square of the speed). The musical "note" from a 2-bladed prop in hertz relates to twice the rpm. I'm sure between us we can help if you need it.
Keep on experimenting - maybe even publish results on Wiki - is some success? Having worked on Engine design in Nissan, the big engine makers are all working flat-out to improve efficiency, low emissions and cost of engines, and their relatively vast resources will always win (just look at Toyota, Daimler or GM!!). But nothing to stop you doing a study on your engine and publishing - if you choose!
Well done!
K2

 

[vederstein]

The five stroke engine is an old idea made new again.

In the steam era, it was called compounding with high and low pressure cylinders.

Also in the steam era, it was done with a single cylinder and called early cut off. Corliss engines did this.

Early cut off was also used in the internal combustion era. The atkinsons cycle which has a short intake stoke, but a long power stroke.

The whole reason is to extract as much energy from the expanding gasses before dumping them out of the engine.

Thermodynamics doesn't change.

...Ved.

 

[Steamchick]

The five stroke engine is an old idea made new again.

In the steam era, it was called compounding with high and low pressure cylinders.

Also in the steam era, it was done with a single cylinder and called early cut off. Corliss engines did this.

Early cut off was also used in the internal combustion era. The atkinsons cycle which has a short intake stoke, but a long power stroke.

The whole reason is to extract as much energy from the expanding gasses before dumping them out of the engine.

Thermodynamics doesn't change.

...Ved.

And Toyota et al are trying to utilise this effect in today's designs of engines....
But turbo-chargers utilise some of the "spare energy" in the exhaust gases to improve the intake (by boosting) - and Turbo-manufacturers have exploited exhaust gas "energy" with alternators as well....
I had a discussion with a Doctor of Mech. Eng. from Sunderland Uni who was investigating fitting a steam boiler just downstream of the catalytic converter of a car engine to see how much power he could derive from hot low-pressure exhaust to power a steam engine driving an alternator - as a project for a post-graduate. This system could also be used to extract energy from the hot, low pressure exhaust from Fuel cells. I think the post-grad was expected to produce a numerical model for computing all of this, and then compare his model to a real set-up.
But it is a distraction from the real "5-stroke' engine here.
K2

 

[NapierDeltic]

There are various methods to extract wasted energy from an engine both from gas pressure and thermal gradient. The recovered energy is quite low compared to already existing output.
Of course I don't expect big engine manufacturers to go in all directions, considering price increase and engine complexity, but engine lovers are allowed to release the dogs of their imagination.
For instance new Peltier semiconductor elements become cheaper, widespread available and more effective and they can recover a lot of waisted heat. Well, Peltier cells are not something to atract machining lovers... , but their output is certain.