Higher efficiency cylinder head by grooving?

[mutantZ]

Has anyone seen this before? Sounds too good to be true. Grooving a combusted chamber netting that much?

 

http://pesn.com/2005/10/13/9600187_Design_to_Improve_Turbulence_in_Combustion_Chambers/

Edited June 22, 2011 by mutantZ

[cockerstar]

It's been discussed before

A quick search should bring it up.

[mutantZ]

Thanks! I guess this will be my first thread that's off to the tool shed.

[Tony D]

I'd say so!

 

"Singh Grooves"

[cygnusx1]

I glued vortex generators to mine.

[JMortensen]

I glued vortex generators to mine.

Pics?

[rejracer]

His point was that a turbulent combustion chamber causes the same effect as multi point ignition. I would agree with this. Anything that will speed up the burn rate in a combustion chamber is better for power, assuming the engine is tuned for it. If we can get the burn rate up, timing can be delayed the proper amount and we are left with greater mechanical leverage as the crank is closer to 90* when peak cylinder pressure is achieved. Not to mention less cylinder pressure while compressing. This nets out to an increase in power. In my opinion 20% is not unrealistic. Keep in mind that the engine he was working on it's basic design is roughly a century old.

 

Do note, that just cutting grooves in a set of heads and running it without tuning it accordingly is not the right approach as it's not complete. He also stated that the compression was raised. There is efficiency increase with just the compression gain.

 

So removing your cylinder head and taking your die grinder to it will get 20%? I don't think so. Raise the compression, modify the combustion chambers, and re-tune it? Now your talking.

[johnc]

In my opinion 20% is not unrealistic.

 

Dang! I'm surprised that Miller, Offenhauser, Chevrolet, Ford, Cosworth, Rolls Royce, Jaguar, Ferrari, Maserati, Porsche, Bugatti, Mercedes, Lamborghini, BMW, Audi, Oldsmobile, Toyota, Buick, Nissan, Mazda, and Pontiac never sold their production or race engines with grooved combustion chambers in the 100+ years the car has been around. Image getting 20% from just a casting change. How dumb can their engineers be? Can i really take my old 325hp N42 head L6, groove the combustion chambers and now make 390hp? No. Never. Not in a million years.

 

Now if I add a Vornado and magnets to my fuel line...

[Tony D]

I could comment, but I would then be caught in the vortex...

[rsicard]

Swirl and quench have just as much or more to do with combustion efficiency in a Wedge design cylinder head. A lot depends upon the design of the cylinder head combustion chamber and a piston to complement same. Adding the groove will likely aid in flame front travel speed. It may NOT aid swirl. GM has done a considerable amount of work on the newest Corvette cylinder heads to enhance swirl. Quench is easier to achieve. Both work together to atomize the fuel mixture for a more complete burn and therefore better efficiency. Automobile manufacturers may tweak combustion chamber design with CFD software but even that is hard to validate its benefit in the design.

[260DET]

Was thinking the other day that a VG33 head may benefit from a groove in the squish area at about ten oclock, pointing directly at the spark plug. Can't see it would do any harm anyway.

 

[rejracer]

I think there is a wee bit of misunderstanding here. My 20% comment was misunderstood.

 

So removing your cylinder head and taking your die grinder to it will get 20%? I don't think so. Raise the compression, modify the combustion chambers, and re-tune it? Now your talking.

 

The 20% I am referring to is basically the power to be had without changing the intake or exhaust manifolds or porting the head. 20% is doable without porting or manifolds. That was my point.

 

Image getting 20% from just a casting change. How dumb can their engineers be? Can i really take my old 325hp N42 head L6, groove the combustion chambers and now make 390hp? No. Never. Not in a million years.

 

Are you reading what I wrote? How did you get 325hp from an engine that was originally designed for 170 or so hp? I am assuming you modified the airflow of the engine, combustion chambers, timing and fuel system. This guy is just talking about modifying the combustion chambers and fuel system. If you are approaching a 100% increase, why do you doubt if this guy is doing a few mods and gaining what he describes as increased torque, lower temperatures, and smoother running. I'm scratching my head as to why this is unbelievable.

 

In my opinion 20% is not unrealistic. Keep in mind that the engine he was working on it's basic design is roughly a century old.

Perhaps I should have elaborated. I was reading up on this before I posted and here is a quote from his website: (and other websites)

 

"After this simple design change ~ Obsolete Side Valve Engines which feature large quench areas have shown reductions of up to 42.5 % in fuel consumption"

 

"I undertook to carry out modifications on a side valve Briggs and Stratton engine - as side valves display the largest squish areas in comparison to over head valve OHV designs"

-Somender Singh

 

He is saying 20-42.5% reduction in fuel consumption, but gives no numbers that I have seen concerning a % power increase. Side Valve Engines are more commonly known as flat heads here in the US. Getting 20% more efficiency out of engine design that is approximately 100 years old is not an impressive feat. Thus my comment above. Now my bad, I said gain 20% right after increase in power. I did not mean to imply a 20% increase in power from the Singh groves. I meant 20% increase in power is attainable by increasing combustion efficiency, which includes introducing turbulence, raising compression and retuning. In the real world this could mean welding up the chambers (or using a P90/P79/MN47/E31 or early E88), fitting flatop pistons, and running Megasquirt, Wolf, Haltec, and tuning it. If doing that many mods on an otherwise stock engine then 20% is not unrealistic.

 

Dang! I'm surprised that Miller, Offenhauser, Chevrolet, Ford, Cosworth, Rolls Royce, Jaguar, Ferrari, Maserati, Porsche, Bugatti, Mercedes, Lamborghini, BMW, Audi, Oldsmobile, Toyota, Buick, Nissan, Mazda, and Pontiac never sold their production or race engines with grooved combustion chambers in the 100+ years the car has been around.

 

While that's a lengthy list of car manufactures, the relevant engine manufacturer has been omitted: Briggs & Stratton. If you've read up on Singh's work, then it's clear that he came to his conclusions by modifying what we consider a lawn mower engine. Some of my comments were in context to his work, others were applying what he was doing to a more modern engine design. Realize he lives in India. When I was there in 2007 it was explained to me "keep in mind when dealing with us (Indian workers) that 20 years ago, we did not know what a color television was". This was told to us by one of the more educated and affluent managers there. He was part of a higher caste. Mr. Singh is modifying engines that they actually use over there in transportation. Makes me want to modify my 8hp briggs that's on my Tote Goat.

 

I never stated or implied that if you cut grooves in your L-series head that you will get 20% more power. I did however say that if you modify the chambers, increase compression, and tune it, 20% is not unrealistic. Since you are already at nearly 100% increase, you've accomplished what Mr. Singh was aiming at concerning combustion efficiency and then some. Albeit the comparison is apples to oranges, regardless, principles applied. My quotes above stand.

 

So to restate my original intent: Any design change that increases the rate of burn in the chamber will yield more power when properly tuned for. Singh grooves may be one means of achieving that, as is quench, as is swirl, as is multipoint ignition, as is getting the ideal fuel mixture for the chamber it's being burned in.

 

Lastly the OP's link had the quote:

"He claims that his invention makes an engine cleaner, quieter and colder than its internal-combustion cousins around the world—while using up to 20 percent less gas." -- (Popular Science; Sep 24, 2004)

 

I've never seen a claim where he states a % increase in power, rather a % reduction in fuel consumption. I said 20% power, but that was not related directly to Singh's work, nor was it the grooves alone. So to restate what I've restated: This discussion is focused on combustion efficiency, how it affects power, and how Singh Groves can be used to increase it.

 

 

Leon / 74Adam,

Do you have anything to add concerning the topic at hand?

 

I could comment, but I would then be caught in the vortex...

 

I did get a laugh out of that one, but do get sucked into the vortex! Just come with understanding of what the originator is and is not claiming, and how it relates to a "modern" engine. Did I just call an L-series modern? Most of the skepticism in this thread is caused from assuming Mr. Singh is claiming the grooves increase power by themselves, or assuming (and not understanding) what I actually wrote.

 

 

rsicard,

Thank you for posting thoughtful content. You are right, ideal grove placement would be dependent on chamber design and layout.

 

260DET,

In a non turbulent open chamber the flame front expands outward from the spark plug in a more or less spherical shape. This is not exactly true due to the result of the compression stroke, it's more like a disc. The gas inside this sphere is in process of or has already combusted. The pressure inside the sphere is the same or very close to the pressure in the rest of the chamber, but the density is far less due to the increase in temperature. This means that the area outside the flame front is slightly gaining in temperature (as a result in the pressure increase), but greatly increasing in density. Turbulence is attempting to deform the natural spherical flame front. When the flame front is deformed the ratio of flame front surface area to volume unburnt gasses in the chamber increases. Simply stated this is just an attempt to expose unburnt gasses to the flame front. This is why multiple grooves are being reported as yielding results. I think what is happening is the groves make a column of gas and thrust it into the flame front, which causes an equal volume of the burnt gasses to be thrust in an opposite direction away from the groove. Instead of a standard quench area expelling a flat sheet of gas, the groves are attempting to expel a column of gas. This column of gas having a bit more volume and mass is able to penetrate the flame front further than a more consistent sheet.

 

If I could get a dual plug head with one spark plug where it is in the L series, and another located at the opposite side of the chamber, I think that would be an ideal physical layout. For an experiment I have been thinking about for a few years. I would do a splayed timing offset between the two plugs. I would ignite the open side of the chamber first. As the piston is moving up the flame front is expanding and compressing the unburnt gasses to the opposite side of the chamber. The gasses think they are safe, but little to they know the other plug is about to fire, and it does, say 5* BTDC. This second ignition event increases the turbulence by rapidly propelling the unburnt gasses in the quench area. Groves or not I believe this would be increasing turbulence in the chamber. But with the grooves the velocity of the gasses in the groove area is greater as the quench effect is forcing the gasses to lesser pressure areas of the chamber. Where I disagree with Mr. Singh is the 70 thousandths rule. Make the piston to deck clearance as small as possible overall, but do more elaborate grooves to channel as much of the mass of gas to increase the flow from the quench area to open portion of the chamber. The goal is:

1. Force as much of the gas to the other side of the chamber as possible

2. Evacuate as much of the gas from the quench area.

3. Increase the flame front surface area to unburnt gas volume ratio

 

So now another event happens, we reach TDC. As much of the gas that is going to get evacuated from the quench area has been evacuated, and the piston starts it's downward travel. The quench area's volume delta is increasing much more rapidly than the rest of the chamber, as a result it's localized pressure is dropping faster. Remember when we forced out the gasses through the grooves. That action caused unburnt gasses to flow in the opposite direction. I would place the grooves so that these unburnt gasses would be as close to the quench pads. Now that the volume of the quench pad area is increasing and the pressure dropping, the hope is that it would pull the unburnt gasses into this area, and hopefully there is still a remainder of the combustion process to support the burning of these gasses. The goal is to have the largest flame front surface area in relation to the volume of unburnt gasses, so the combustion process completes in less degrees of crankshaft rotation.

 

Anyhow that's my theory on how this would work based on my understanding of what's happening in a combustion chamber. If any of you wish to refute it, please do so intelligently. I'd like to learn so I can more more fully understand how design affects the combustion process.

[260DET]

"... Turbulence is attempting to deform the natural spherical flame front. When the flame front is deformed the ratio of flame front surface area to volume unburnt gasses in the chamber increases. Simply stated this is just an attempt to expose unburnt gasses to the flame front. This is why multiple grooves are being reported as yielding results. I think what is happening is the groves make a column of gas and thrust it into the flame front, which causes an equal volume of the burnt gasses to be thrust in an opposite direction away from the groove. Instead of a standard quench area expelling a flat sheet of gas, the groves are attempting to expel a column of gas. This column of gas having a bit more volume and mass is able to penetrate the flame front further than a more consistent sheet..."

 

Yeh, that was my thought, it improves the efficiency of the existing squish/quench effect. VG33 engine has a large squish area so it might respond well to such mods.

[rejracer]

I don't know how well it will, it looked somewhat small. But the VG chamber design looks like it may respond better to this than an L series. I do think it will help the burn rate, but I just want to be clear this mod alone is not going to yield a 20% power increase. I would be pleased if it got 1.5% more power over a well set up high quench design. A tad more over a open chamber head, assuming you swapped to a closed chamber head, yet left CR the same. I would also like to make clear I am not trying to step on anyone's toes on this, I'm just making the point that the idea has merit, just like a standard wedge head and turbulence.

[Tony D]

Knowing someone who works at Briggs & Stratton, when mentioning the aforementioned experimenter...they did do some testing, but there was more they needed, and his development didn't get them where they needed to be so it was left with him.

 

Which goes to John C's comment about all the other engine manufacturers...

 

S. Singh has some interesting developments. But they are ONLY applicable to areas of the world where advanced engine control and emissions are not a concern.

 

20% increase on a Flathead, that IS something, and I'd not dismiss it. But what works on one engine design doesn't necessarily prove beneficial on another design. Not a lot of advantage for the claims put forth in the end.

[johnc]

If we're here to discuss flatheads and side valve engines then I concede that there might be some benefit to cutting grooves in the cylinder head. I still doubt it, but hey, those engines were designed for 70 octane fuel and, with today's fuel, its hard to a compression ratio much above 10 to 1 without a lot of detonation. Maybe cutting grooves will help. Either way, IMHO, its of no benefit to any of the engines that are installed in the HybridZ member cars, unless someone I don't know is running a flathead.

[Tony D]

Never Say Never John!

 

Our El Mirage competition the year we took the points championship was an XO/BFCC combination running a blower and Hilborn Injection on a Flathead IN A PINTO!

 

We are the automotive anachronisms: Land Speed.

 

Where else can you see a Buick Straight-8 and Offy Indy from 1929 still in active competition?

 

No, we DON'T have anything better to do, come to think of it...

 

But even at that level of competition, I don't know any of the flathead guys who are doing Singh-Grooved Cylinder Heads.

[260DET]

What would be helpful is educated comment on the proposition that a groove cut in the squish/quench area of an OHV engine would create combustion assisting turbulence. It's proven that squish areas assist combustion, it seems reasonable to me to consider if the surface shape of such areas may be relevant as well.

[rejracer]

Here is some test data:

 

Click here for test data

 

In summary at part throttle or lower RPM there is a net loss of torque.

 

At higher loads and RPM's there is a gain. Now get this: The largest improvement I found in the document was a 17% increase in torque output. There may be higher.

 

This was tested on a Geo Metro engine, 2 heads were re-manufactured to stock specs, one of them modfied with the Singh Grooves.

 

Does this qualify as legit test data?

 

 

260Det,

Yes it's very reasonable to consider it. I've seen some of the pics on the net, all I can say is I'm surprised some of those cars run after they are done. One thing concerning the testing is that even the above test data, the compression on the engine is lower than on the stock head. I would like to see another test where the chambers are welded up a bit in an area that is not going to alter the turbulence at all, just even up the compression ratio. I think the loss of compression may be lowering the torque output at lower RPM's. To what degree remains the question.

 

 

-Robert

Edited June 28, 2011 by rejracer

[rsicard]

Good combustion is a combination of aspects. Using the Small Block Chev as a baseline, the best pistons for combustion flame travel are flat tops. Admittedly there needs to be valve reliefs cut into them for valve clearance. For real good squish an all forged bottom end is necessary as it provides the least flexing of reciprocating components. Then the block can be decked to near zero wherein the piston is flush with the top of the block. Then the cylinder head flat face of the combustion chamber can be torqued to within 0.025 to 0.030 inches of the top of the piston with thin head gaskets. When this gap is reduced the resistance to detonation is significantly reduced. Additionally, swirl is enhanced also. With good squish and swirl the incoming fuel and air mixture is homogenized more thoroughly and therefore the flame front will migrate much faster through a homogenized mixture than a richer mixture portion of the combustion chamber. Adding grooves directs the mixture on the opposite side of the chamber towards the flame front caused by the spark plug thereby speeding up the burning of the total combustion chamber mixture of air and fuel.

 

The LT-1 Small Block Chevrolet (Gen II SBC) engines were 10.0 to 1 compression from the factory and ran very well on 87 octane fuel. I had one of these in a 1994 Buick Roadmaster and went to emissions and there was so little of it that emissions equipment reported zero zero. Best running engine I have every had and kept it that way well past 100K miles and still running strong passing most everything in sight. From Tucson to Phoenix and return at 80 MPH it got 24 MPG and it was a HEAVY vehicle! When the tune is right, the emissions will be exceptional! It is really hard to beat a good design engine that has a good Electronic Fuel Injection (EFI) with a very precise Ignition System.

 

Now I have an even better (more tunable) EFI system for my 240Z which is getting a 383 SBC.