18 replies to this topic

[TDIMeister]

So there's yet another engine startup who claims to have the next big thing - this being a big displacement I4 engine that solves the bane of this type of engine: secondary imbalance as one gets bigger.

 

The below videos and patents by the company show their concept to be a variation of the Scotch Yoke or "Bourque" engine done as in inline 4..

 

(I like this channel, BTW, it's one of the better ones IMO).

 

https://patents.goog...US10012145B1/en

https://patents.goog...US10378578B1/en

https://patents.goog...US11098750B2/en

https://patentimages...020014698A1.pdf

 

The CEO wisely and astutely said that they won't disclose their secret sauce, otherwise everyone will copy it - patents or not. So, I think the patents and reference to the Scotch Yoke / Bourque engine are all a ruse - a red-herring - a canard - from what they're actually doing because the Scotch Yoke / Bourque engine has intractable issues with the sliding line contact at the crank journal. It is my speculation that they are working much more like something like the below. I showed a video by this creator before. He's been making a few new videos since that time making minor modifications and refinements since.

 

Discuss!

 

PS: For full disclosure, I have been working for a number of years separately on a type of sinusoidal mechanism engine, a new prechamber design, and a non-air-breathing engine (submitted a WPT patent application in 2020 for the last) but that's all I'm willing to disclose.

 

Edit: There's a funny line from the movie The Departed (2006) starring Jack Nicholson, Matt Damon and others that I think is fitting: "My theory on feds is that they're like mushrooms; Feed 'em sh!t and keep 'em in the dark." 

Edited by TDIMeister, 21 November 2022 - 03:02.

[Greg Locock]

I think you mean the Bourke engine.I had a bit of correspondence with a couple of entertaining enthusiasts , one of whom assured me he'd have it in production within 2 years. 

 

In a Bourke engine how do the piston rings get lubricated?

Edited by Greg Locock, 21 November 2022 - 05:03.

[TDIMeister]

Yes, sorry, my typo error. I am indeed referring to the Bourke engine.

[GreenMachine]

I am quite sure this has been discussed here in the not-so-distant past, but putting 'alfadan' in the search box produced a nil result 

[desmo]

Color me cynical but nobody who has access to enough money will in a million years be stupid enough to throw resources into the money pit of trying to develop this "mystery" design with no (even claimed!) efficiency upsides. You know they've pitched this to the OEMs and they didn't take the bait. By the time something like this is in the open public on the internet "looking for individual investors" phase (keeping the actual concept secret and unpatented is a particularly cynically bold and flagrant red flag) , it means all the smart money has already run screaming away and they are desperately chasing easy, stupid money before they inevitably throw in the towel permanently. This is therefore a dead concept walking, in its terminal phase, at this point only looking for naïve marks to fleece before they move on to the next "investor" scam. No I didn't watch the pitches, they are essentially all the same. There will be no further major design developments in piston ICEs again, the design has already reached its logical and developmental endpoints.

[TDIMeister]

Color me cynical but nobody who has access to enough money will in a million years be stupid enough to throw resources into the money pit of trying to develop this "mystery" design with no (even claimed!) efficiency upsides. You know they've pitched this to the OEMs and they didn't take the bait. By the time something like this is in the open public on the internet "looking for individual investors" phase (keeping the actual concept secret and unpatented is a particularly cynically bold and flagrant red flag) , it means all the smart money has already run screaming away and they are desperately chasing easy, stupid money before they inevitably throw in the towel permanently. This is therefore a dead concept walking, in its terminal phase, at this point only looking for naïve marks to fleece before they move on to the next "investor" scam. No I didn't watch the pitches, they are essentially all the same. There will be no further major design developments in piston ICEs again, the design has already reached its logical and developmental endpoints.

Yeesh - cynical indeed!

[GregThomas]

Yeesh - cynical indeed!

But probably true - as it relates to fourstrokes.

[PJGD]

"There will be no further major design developments in piston ICEs again, the design has already reached its logical and developmental endpoints".

 

 

This may be true for light duty vehicles, but is not true for commercial applications.  For example, Cummins and Daimler have recently joined forces to develop a new medium duty commercial vehicle engine.  Also, there are plenty of off-road applications that will be difficult to electrify and a lot of thought is being given to how they might be adapted to operate on various low carbon fuels in the future.  This is likely to lead to some unique or less common solutions such as VCR and other relatively novel features.  Note: I am not expecting the Alfadan engine to be among the future commercial engines.

[Greg Locock]

Agricultural tractors seem to me to be a biggish problem. When you are ploughing you often have a bowser at the side of the field, 200 hp continuous is a big electrical load for 12 hours a day. Especially if you are out in the sticks.

[GregThomas]

Amazingly we had electric tractors local to me in NZ in the 1930's  Google Samson Grip Electric tractors if you're interested. The guy who developed them was Chief Engineer for the local Electric Power Board in rural South Canterbury.

[Greg Locock]

I am interested but my google-fu fails me. The best i can find is An electric tractor works alongside a horse team in Canterbury in the 1930s. The electric tractor was developed in Ashburton to increase local demand for electricity. Although the machine looked cumbersome, with its pivoted turret through which the feeder cable was passed from a transformer on a nearby truck, it worked quite well. The eight machines built managed over 8,000 hours work between them. However, tractors driven by oil fuels proved cheaper to run.

https://teara.govt.nz/en/photograph/18408/electric-tractor

[Greg Locock]

https://www.stuff.co...wer-to-the-land

 

Not an official Samson though, they were gone by 1930

[GregThomas]

I'd been told about them as a kid. But that link is about all there is on line I think.

[manolis]

Hello all.

 

TDiMeister wrote in another discussion:

“On another note, I would appreciate your input in this thread: https://forums.autos...adan-i4-engine/”.

 

 

The Alfadan 4-in-line engine does balance the second order inertia forces of the conventional 4-in-line.

 

The question is: at what cost?

 

It multiplies the unbalanced inertia toque on the casing and the shear stress of the crankshaft,

it needs extra “linear” bearings at the bottom of the casing,

its piston assemblies cannot be as stiff as necessary at high revs,

it increases the thrust load and the friction loss,

it is based on unconventional and untested (or unsuccessfully tested: CMC etc) technology.

 

 

In the Alfadan engine the conventional piston – wrist pin – connecting rod assembly is replaced by the cyan and orange parts:

 

 

The cyan part cannot help being a few times heavier than the set of the conventional piston / wrist pin / “upper” connecting rod (“upper” meaning about 1/3 of the weight of the connecting rod; to get an idea for these weights, in the Honda 1600cc V-tec (B15A2) sport engine, the piston weighs 300gr, the wrist pin 100gr and the connecting rod 600gr).

 

Why the piston of the Alfadan cannot help being so heavy?

 

Because it needs to be quite inflexible, despite its big opening (the opening inside which the orange part is trapped and slides).

 

Consider the piston of the Alfadan engine is at the overlap-TDC (no pressure in the cylinder) at high revs.

Who keeps the piston from hitting the cylinder head?

The long horizontal beam (1008 – 1012) which, supported at its middle point on the orange part, is keeping - by its ends - the upper piston structure.

 

 

At high revs, at the overlap-TDC (note: the other TDC is the combustion-TDC) a conventional connecting rod is so heavily loaded that it extends dangerously with the piston approaching the cylinder head. In some cases this puts the limit for the rev limiter.

 

If a connecting rod loaded in tension extends, say, by 0.5mm at top revs, imagine how much the horizontal beam (1008 – 1012) will bend.

And when it bends, the orange part looses contact with the top slider of the big opening and later it lands (or strikes) on it.

 

 

Unbalanced inertia torque:

 

The necessarily heavy piston assembly of the Alfadan engine increases proportionally the unbalanced inertia torque on the engine casing and on the gearbox.

 

The thinking is simple: all the four pistons of the Alfadan stop together (the two at TDC, the other two at the BDC, all with zero velocity) and after 90 crankshaft degrees all the four pistons move with their maximum speeds at middle stroke.

 

Somebody (the crankshaft, the flywheel, the gearbox and the rest vehicle) has to provide kinetic energy to the four heavy pistons when they accelerate, and absorb kinetic energy from the four pistons when they decelerate. All this idle energy (and idle power) reciprocates between the crankshaft and the pistons. The crankshaft with the flywheel tries to keep constant angular velocity while the pistons try to keep their velocities and to accelerate / decelerate the crankshaft with the flywheel, with the crankshaft undergoing heavy to extreme shear loads.

 

For more, there is the discussion https://forums.autos...que-and-patvra/

 

 

Vibration free? And the free inertia torque?

 

As compared to a similar conventional 4-stroke even-firing 4-in-line engine (say: same bore, same stroke, same rpm) which suffers from a heavy 2^nd order unbalanced inertia force and a heavy 2^nd order unbalanced inertia torque, the Alfadan engine is free of 2^nd order unbalanced inertia force, but suffers from a several times heavier 2^nd order unbalanced inertia torque (which may require a pair of balance shafts in order to be cancelled out . . .)

 

 

Thrust loads:

 

The old CMC Scotch-Yoke prototype engine is the boxer version of the Alfadan engine:

 

 

As compared to its boxer version, the Alfadan suffers from two times heavier thrust loads between the piston skirt and the cylinder liner. Easy to think why.

 

 

So,is there a simple / conventional way (without external balance shafts) to achieve the same?

 

Start with a V8-90 degrees engine with flat crankshaft, say like the engine of the new GM corvette:

 

 

Remove the cylinder head from the one bank of cylinders and turn it 90 degrees to form a V180 engine, then turn the engine 45 degrees, say like:

 

 

What you get is a four-in-line 4-stroke even-firing full balanced (as regards its inertia forces) engine.

 

Optionally the lower cylinders can be removed, the lower pistons can be replaced by weights/sliders, and the lower connecting rods can be substantially shorter, and yet the engine be perfectly balanced as regards its 1^st and 2^nd free inertia forces.

And the solution is completely conventional.

 

Drawback is the increase of the inertia torque as compared to a similar conventional 4-in-line.

 

Optionally, the “bottom” cylinders and pistons (or bottom weights and sliders) can be replaced by side connecting-rod-weights like those in the BMW 800S twin:

 

 

 

Conclusion

 

The Alfadan design solves a problem creating several other problems which are way more difficult to be solved.

 

 

If something is confusing please let me know to further expain.   

 

Thanks

Manolis Pattakos

[TDIMeister]

Once again, thanks very much for the thorough comment, Manolis!

 

Can you also comment about the variant simple harmonic design in this and other videos made by the same content creator Craig Laycock?

 

https://www.youtube....rcraigpl/videos

 

Thanks!

Edited by TDIMeister, 07 December 2022 - 17:46.

[manolis]

Hello all.

 

TdiMeister wrote: “Can you also comment about the variant simple harmonic design in this and other videos made by the same content creator Craig Laycock?”

 

 

 

Problems I see:

 

Each piston comprises a more than heavy ring-gearwheel. Why so heavy? Because it has to be stiff (and not flex) despite the strong forces it deals with.

 

For 100mm piston stroke, the pitch cycle diameter of the gearwheels on the crankshaft is 50mm and the cuts from the teeth go deep into the crankpin of the crankshaft.

The pitch cycle diameter of the ring gearwheel is 100mm.

The eccentricity of the crankpins halves as compared to a conventional engine having the same piston stroke.

 

With the crankshaft not having balance webs (there is no space for them: the piston at BDC almost touches the crankshaft journals), the overall free inertia force is zero, however the inertia force on the crankshaft bearings is too heavy. The crankcase has to be way stronger than conventional. If there were balance webs, the peak load on the crankshaft journals would half (it would still be too heavy, but at least they would halve) .

 

For each piston there is a brown-red bearing part (a kind of “connecting rod”). This part has a big diameter external bearing (not good at high revs), and a small diameter inner bearing by which it abuts on the respective crankpin and rotates at double speed there on (if the engine revs at 6,000rpm, the brown-red part “rotates” around its crankpin at 12,000rpm).

 

The cylinder liner receives heavy thrust loads.

 

Inertia torque:

 

As the revs increase, the crankshaft will soon fall apart.

With the four extra-heavy pistons stopping together (two at TDC and two at BDC), and maximizing their speeds simultaneously at middle stroke, the inertia torque on the casing and on the crankshaft can be several times heavier than in a similar conventional engine.

The long crankshaft "connects" the flywheel (that tends to keep constant angular velocity) with the four heavy pistons that stop and accelerate simultaneously two times per crankshaft rotation.

The crankshaft besides being loaded by extra heavy torsional inertia loads (2^nd order inertia torque), it cannot help having thin crankpins (less than half piston stroke) located at halh eccentricity relative to a conventional crankshaft for same piston stroke.

 

The long crankshaft with the thin, and of small eccentricity, crankpins seems as the weakest point of the design.   

 

The previous were for the ability of the engine to rev reliably at high rpm.

 

Balance quality:

 

The balance quality of the engine is not better than a conventional four in line. The 2^nd order free inertia force is completely cancelled, however the 2^nd order free inertia torque is several times heavier. The vehicle will vibrate in a different way.

 

 

 

 

Here is an alternative:

 

 

Besides being PERFECTLY BALANCED (as perfectly as the Wankel Rotary engines and as perfectly as the best V-12 conventional engines: zero free inertia force, zero free inertia torque and zero free inertia moment), the engine is also compact (no offset between the two banks of cylinders, short distance from cylinder gasket to cylinder gasket) and lightweight: the mass of each double piston (i.e. the reciprocating mass per two cylinders) is close to the reciprocating mass per cylinder (piston mass, plus wrist pin mass, plus about 1/3 of connecting rod mass) of a conventional 4-cylinder engine having similar bore and stroke.

 

Here is a prototype made a few decades ago (the balance webs of the animation are missing):

 

 

The half-block shown at bottom is from an Alfa Romeo 1200cc boxer engine, from where they are also the four piston :”heads”.

 

 

And the kinematic mechanism exploded:

 

 

 

For more: https://www.pattakon...PE.htm#harmonic

 

Thanks

Manolis Pattakos

 

[TDIMeister]

This article is germane here:

Huge 3.6L Four-Cylinder Claims 500 LB-FT With LS Head and a Turbo

https://www.thedrive...ead-and-a-turbo

 

Note that this is not a running engine but purely a concept. There's no doubt why. The secondary imbalance would be quite insane. No balance shafts are visible in the photographed mule and none are indicated.

Edited by TDIMeister, 19 December 2022 - 18:15.

[gruntguru]

Couldn't find a power rating or max rpm anywhere. The secondary imbalance won't be an issue if the revs are kept low enough.

[TDIMeister]

True. After all, the Cummins 4BT and successor displace 3.9 and 4.5 L with heavier reciprocating components, but they're not expected to rev above 2500 RPM.