Video describing Inline Four cyl. vibrations and 7.5 litre experimental engine

[husky drvr]

The first half of the video describes Inline Four cylinder vibrations and causes - primary and secondary.

The second half is about an engine development program for a large displacement Inline Four with a different kind of connecting rod design that supposedly modifies the secondary vibrations to allow large displacement L4's.

Any thoughts about the design difference that would allow reduced secondary vibrations? The only thing I can think of would probably not be readily adaptable to a physically small engine.

 

[spmdr]

Reality, at least in the peoples republic of California, USA, is that Combustion engines

have been Dis-invited in the Land...

But, Maybe NOT the Water?? ;-)

Sounds like that engine should be well developed in time to be BANNED.

in CA.

DW

 

[Bill Blue]

It's hard to imagine a redesigned connecting rod that is not multiple pieces operating together. If so, the simplicity of the four banger goes out the window. Would a scotch yoke count? Its certainly not simple, nor is it new.
Bill

 

[spmdr]

This subject reminds me of stories of cars with BIG CID Offy 4s,

You knew when it was time to up shift when the Engine Vibration was so Bad

it was a challenge to keep a Hold of the Steering Wheel!

DW

 

[husky drvr]

Bill,

Don't think it's a Scotch yoke, at least the CEO says it's not in a follow-up interview video. And definitely not the patent number that many seem to think is applicable.

I was thinking maybe a sliding shaft style two piece rod, but that doesn't actually change the piston speed changes.

Have fun,

 

[Bill Blue]

I think the sliding shaft makes the situation worse as it increases con rod angle. Interesting that he never looked at the Queen of the big displacement fours, the 1910 Alfa, dubbed the Monster of Milan. Something like 1350 cu. in. I do remember that each cylinder was about the same as a Chevy 350!

All in all, I'm finding the current discussion on building a racing 1725 fascinating, makes me want to "do" one, detuned for the street. A lot info there.

Bill

 

[spmdr]

...Not that I have spent much time thinking about it,

But, I'm thinking No Rod, per say.

The piston is directly connected to the "Crankshaft"

And the "crankshaft" does not have a Round or radius "throw"....??

...he says without even looking at the above links...

DW

 

[Bill Blue]

So thinking along the lines of a cam roller following a groove in the crankshaft counter weight?
Bill

 

[spmdr]

Back about 10 years ago, I did some Patent searches about

I concept I had in High school And I wondered if anyone

had patented it, because I had not seen anything like it in use.

I found a patent that was so vague and All covering, I was amazed

it was granted.

I had always thought Patents needed to be quite specific,

I found that is not always the way it is.

And defending a patent is likely an Art form.


....so, Bill, your question is WAY too specific..... ;-)

DW

 

[Bill Blue]

Back about 10 years ago, I did some Patent searches about

I concept I had in High school And I wondered if anyone

had patented it, because I had not seen anything like it in use.

I found a patent that was so vague and All covering, I was amazed

it was granted.

I had always thought Patents needed to be quite specific,

I found that is not always the way it is.

And defending a patent is likely an Art form.


....so, Bill, your question is WAY too specific..... ;-)

DW

Especially since engines have been built around the concept. Usually in configurations that are way more interesting than inline fours.
Bill

 

[husky drvr]

Some observations -

>Two cylinder prototype possibly is the minimum size cylinder bank to allow this system to operate.

>Production goals 7.5L (~458 cu. in.) L4 - 654 HP @ 5500 RPM gives 1.875L/cyl(~ 114.5 cu. in. per cyl) with 163.5 HP/cyl ~ approximately 87.2 HP/L
--four valves per cylinder will probably be a bit over-square bore to stroke - GUESSTIMATION about 5.47 bore with 5.0 stroke

> Marine engines are usually designed around the criteria > High power and torque at max RPM for use as a constant speed power source. They are run at, or near, max power production for extended periods - cruise to max - similar to aircraft engine power usage. Marine engines require extreme durability compared to automotive usage.

>The linkage between the crankshaft and piston must be capable of transferring power in both directions without excess tolerance or over-center lock-up - compression stroke versus power stroke.

> Crankshaft must be capable of connecting and delivering the power output of four cylinders into a single output for connection to the gearbox.

>Pistons must be driven without connecting rod angularity, or by linkage that counteracts angularity with an opposing angularity.

> don't loose sight of the KISS principle

My thoughts are tending towards the Commer "knocker" diesel engine and its piston linkages. Not the correct answer but a different direction with possibilities.

Then again, with hydraulically actuated valves - why not hydraulically driven pistons?

Don

 

[Bill Blue]

Then again, with hydraulically actuated valves - why not hydraulically driven pistons?
The thought crossed my mind, but but was drowned out by the Niagra Falls of oil flow. Each cylinder would be an oil pump. Zero head, but huge flow. Hard to think that would be simpler and lower power loss than rotating mass.

Bill

 

[husky drvr]

The thought crossed my mind, but but was drowned out by the Niagara Falls of oil flow. Each cylinder would be an oil pump. Zero head, but huge flow. Hard to think that would be simpler and lower power loss than rotating mass.

Bill,

Think I agree with your assessment on hydraulic drivers - that was actually a bit tongue in cheek.

Is there a possibility of using a device similar to a variable cam timing motor programmed to modify the motion between con rod angularity and piston drive rod in the slider crank configuration? The angularity of the crank connecting rod gives a very small imbalance, compared to engine mass, if it is decoupled from the mass of the pistons.

 

[Bill Blue]

Having a hard time wrapping my brain around the variable cam timer with the slider configuration. But if you are going to introduce "wasted stroke", why not do it with the traditional con rod, so that 90 degree of crank rotation = 50% stroke?
Bill

 

[husky drvr]

Having a hard time wrapping my brain around the variable cam timer with the slider configuration. But if you are going to introduce "wasted stroke", why not do it with the traditional con rod, so that 90 degree of crank rotation = 50% stroke?
Bill

No wasted stroke. Only adjusting timing of piston position during stroke - slow piston travel first half of down stroke and speed up second half of down stroke. Need only to adjust piston travel by amount of stroke difference caused by rod angularity. The adjustment happens twice in each cycle of rotation- starting at TDC and reversing at BDC. Adjustment is reversed on up stroke.

The only way to achieve 50% stroke at 90* crank angle is to have the crank pin center aligned with the piston pin. The issue there is the crank pin can't be aligned with the piston pin at the 270* crank position. It wont be aligned at TDC or BDC either. A much worse case for engine durability.

Hope this helps,

 

[Bill Blue]

Slow piston, then accelerate piston. Hydraulicly. What happens to the oil? What powers the extension in the second 50% of stroke and the up stroke adjustment?
Bill

 

[husky drvr]

Bill,

I think I'm at a point where I can't/wont further explain verbally. Actually as I ruminate this idea, I think I've determined a way to achieve the desired results strictly mechanically - sinusoidal piston reciprocation. This is also the point where I'm reluctant to discuss this further on an open forum because of Alfadan's intellectual properties that haven't come on the market yet.

For me this was just a mental exercise to see if a way to achieve sinusoidal piston reciprocation, in a possibly marketable form, could be determined. I have no interest in unveiling this info, possibly to Alfadan's detriment, or exploiting the possibility that I know what I'm talking about. It was just a mental exercise.

I will state this, if you wish to gamble an investment, I think Alfadan has at least a 50-50 chance of delivering a drive train very close to their claims.

If our paths ever cross again, and you are interested in discussing this topic, I'll try to draw an understandable sketch which we can discuss.

Have fun,

 

[Bill Blue]

Don, how can you compromise something you've never seen or been informed of? It seems quite a bit of work has been done to generate sinusoidal piston reciprocation, so it is not a totally new field.
Bill

 

[husky drvr]

Don, how can you compromise something you've never seen or been informed of? It seems quite a bit of work has been done to generate sinusoidal piston reciprocation, so it is not a totally new field.
Bill

Bill,

I probably can't compromise anything. Information that is presented publicly might allow someone else to do so, though.

Although a lot of work has been done in the field, has any system been brought to market successfully for an ICE? The problem is there isn't much of a need to develop sinusoidal piston reciprocation in an ICE because the rod angularity usually gives a small performance gain for NA engines. Alfadan has to overcome that drawback as well. The stated goals for ~ 1.4 HP/cu. in. indicates the designers think they can. Time will tell.

If Alfadan can, I see no reason to even partially diminish their achievement, even unintentionally.

This might be influenced by the confidentiality agreement I once worked under, and the impression that left with me.

Or maybe just the fact I attended engineering classes long enough to just appreciate what Alfadan might achieve.

Lastly, it was just my exercise, with you in the role of "Devil's advocate," no other real participation.

Time will tell,