A work of pure genius! - Brilliant "Revetec" Engine

[Bob]

Originally Posted by hightower99

I have no idea what you are on about I did not directly compare the X4 to another engine. I didn't say it had poor performance either. I was merely commenting on the low specific output.

THe phrase "low specific output" implies comparison. Unless you are comparing to something else, the word "low" is null. So yes, by saying it has "low specific output" you were comparing it to other engines. And a completely worthless comparison at that, since it was only tested very low in the rev range.

[hightower99]

Originally Posted by Bob

THe phrase "low specific output" implies comparison. Unless you are comparing to something else, the word "low" is null. So yes, by saying it has "low specific output" you were comparing it to other engines. And a completely worthless comparison at that, since it was only tested very low in the rev range.

My point was not to directly compare it to another engine and especially not an automotive one like the 2.4L from a toyota.

I commented on the low specific output.

I consider it low specific output because there are engines that could be compared to it fairly.

Take this engine for example: ULPower UL260i - Wikipedia, the free encyclopedia

A few notes:
It produces a very slightly higher specific power but:
Note the CR
note the fully operational installed weight
note the power to weight ratio
Finally note the BSFC (roughly 241g/kWh - 268g/kWh)

You could also look at something like a Rotax 912ULS (100HP) or even the Jabiru 2200 (85hp)

I am interested in engines that are fuel efficient aswell as producing high specific outputs as those two values normally trade off each other (higher specific output normally means less fuel efficiency, while greater fuel efficiency normally requires lower specific output). An engine that is able to do both is better than either the high specific output engine or a high fuel efficiency engine IMO.

[revetec]

Hightower99:
Our output will increase greatly with further top end development. We haven't even tried another camshaft in the engine yet, and the cylinder head has had little development (took me two weeks to fully design with no CFD or flow testing) This will all come to fruition with development with involved manufacturers and our own development.

Note in the report that we tested up to 3,500rpm at which point the power and torque were still on the rise. The testing we did was on the fuel efficiency side which we proved without a doubt that our bottom end is more efficient than a conventional engine. We had low BMEP which tells us that the top end is not doing an optimum job, but then our output at the target BMEP was good providing unparalleled fuel efficiency. The next stage is to sign with automotive manufacturers and develop an efficient top end for each manufacturers requirements and then produce.

You can go on and on like you have been and I have proved the efficiency to everyone without a doubt. I didn't state that we were going to produce the best power figures in the test, rather than the best efficiency, and I have.

Now just imagine what we will do with an optimum combustion chamber design, 4 valves per cylinder, variable valve timing, variable length intake, direct fuel injection etc.

All this will all come and the figures will get even better as we go. Also remember that this engine was designed by one person (me) in 3 months and the two of us made the engine to running stage in just over 3 months. We have made only one modification to the engine and was sent to Orbital after 15minutes of running time.

So I've proved time and time again your arguments against the engine and now we have top BSFC figures you've decided to now argue outright performance? Well we will prove you wrong once again soon. You'll then argue reliability, which then we will prove. What are you going to argue about then?

below is a dyno chart of the 1.35litre engine and the X4 aircraft engine.



BTW: our 1.35litre engine produced 52kW with 4 valves per cylinder and a CR of 8.5:1 (low as well)
The engine you are talking about (ULPower UL260i) is a 2.6litre (about double) which produces 71kW.
Our last series engine was half the capacity, so let's double the output and we get 104kW.
At 3,300rpm which is their peak of 71kw, our RHL4 engine produced 42kW, it's half the capacity.
So let's look at kW per litre at the same RPM...
ULPower UL260i 2.6 litre has 27.3kW@3,300rpm per litre
Revetec RHL4 1.35 litre has 31.1kW@3,300rpm per litre.

And we did it probably using far less fuel.

So now your argument is?

[Matra et Alpine]

Originally Posted by revetec

So now your argument is?

Size of his member ?

[hightower99]

Originally Posted by revetec

Our output will increase greatly with further top end development. We haven't even tried another camshaft in the engine yet, and the cylinder head has had little development (took me two weeks to fully design with no CFD or flow testing) This will all come to fruition with development with involved manufacturers and our own development.

If you read what I posted I said I know that this particular engine is not designed for producing great power figures and has been optimized for fuel efficiency. I fully believe that you can do better with better top end technology.

Originally Posted by revetec

Note in the report that we tested up to 3,500rpm at which point the power and torque were still on the rise. The testing we did was on the fuel efficiency side which we proved without a doubt that our bottom end is more efficient than a conventional engine.

If this is the aviation version of the engine then why would you want more than 3500RPM?

Without a doubt? really? I don't see how this single report conclusively proves that your bottom-end technology is more efficient than current designs. You only tested a single RPM point at a single load point which showed (IMO great) BSFC values. You are going to have to make a full BSFC map for the whole operational RPM range and load range. Not that there is an abundance of BSFC maps to compare it to that are publically available. Does anybody know what the currently most efficient petrol engine is?

Originally Posted by revetec

We had low BMEP which tells us that the top end is not doing an optimum job, but then our output at the target BMEP was good providing unparalleled fuel efficiency.

I will agree that part of the lower BMEP was top end design but didn't you achieve better than this in another test? Also how can your output at your target BMEP be good? (as compared to bad?) there is a direct relation between BMEP and output for any given RPM, the higher the RPM that your target BMEP occurs at, the greater output you will produce at that BMEP. Also the statement "providing unparalleled fuel efficiency" would imply that you have compared your results to another engine. Would you show us what engine you are comparing your results with?

Originally Posted by revetec

You can go on and on like you have been and I have proved the efficiency to everyone without a doubt. I didn't state that we were going to produce the best power figures in the test, rather than the best efficiency, and I have.

I am fully aware that this engine was not designed with high specific output in mind, also this report is not conclusive proof of revetec fuel efficiency superiority.

Originally Posted by revetec

So I've proved time and time again your arguments against the engine and now we have top BSFC figures you've decided to now argue outright performance? Well we will prove you wrong once again soon. You'll then argue reliability, which then we will prove. What are you going to argue about then?

I think you meant to write "disproved" but maybe that was a freudian slip Who said I was finished arguing BSFC? as of yet you have data for a single RPM point and a single load (that where any good)... so what? Show me a full RPM and load range graph and that would be closer to proving any gains.

Originally Posted by revetec

Our 1.35litre engine produced 52kW with 4 valves per cylinder and a CR of 8.5:1 (low as well)
The engine you are talking about (ULPower UL260i) is a 2.6litre (about double) which produces 71kW.
Our last series engine was half the capacity, so let's double the output and we get 104kW.

There you go again completely missing the point... Why are you suddenly comparing an aviation engine to your previous design? I thought the RHL4 was designed for automotive use (you put it in a car remember?) Also where is this "double the output" coming from. The UL260i is comparable to the X4 because it is a 2VPC 4 cylinder aviation engine of roughly the same displacement. It is one of the engines that the X4V2 will be competing with if it comes out on the market. As far as I can see it doesn't have that much to offer (a single highly efficient operating point is about it).

Originally Posted by revetec

At 3,300rpm which is their peak of 71kw, our RHL4 engine produced 42kW, it's half the capacity.
So let's look at kW per litre at the same RPM...
ULPower UL260i 2.6 litre has 27.3kW@3,300rpm per litre
Revetec RHL4 1.35 litre has 31.1kW@3,300rpm per litre.

So your previous design got better specific power... Does that mean you are going backwards? or maybe this comparison is just flawed.

Originally Posted by revetec

So now your argument is?

When the X4V2 comes out on the market for aviation engines what exactly is it going to offer over the alternatives?

Don't just say it is more efficient and point out the single point that was tested. You need at the very least a part-throttle full RPM range average to make any big claims (increased bottom end efficiency).

[hightower99]

Originally Posted by Matra et Alpine

Size of his member ?

a dick joke?

at my expense?




For shame!

[Matra et Alpine]

Originally Posted by hightower99

a dick joke?

at my expense?




For shame!

Not really ... for humour

Originally Posted by ht

I think you meant to write "disproved" but maybe that was a freudian slip

Brain slip on you. Brad said he'll PROVE reliability

(it would be disprove of UNreliability, but that's very bad English )

Put the can of pterol on the ground and step away .......

BTW, how are your engine design/builds going ? Keep looking for the thread on it so it can be discussed ......

[revetec]

Originally Posted by hightower99

If you read what I posted I said I know that this particular engine is not designed for producing great power figures and has been optimized for fuel efficiency. I fully believe that you can do better with better top end technology.

Thank you.

Originally Posted by hightower99

If this is the aviation version of the engine then why would you want more than 3500RPM?

Exactly,

Originally Posted by hightower99

Without a doubt? really? I don't see how this single report conclusively proves that your bottom-end technology is more efficient than current designs.

2,000rpm, 450kpa BMEP, best BSFC 207g/kW-h
So how did we get such good fuel efficiency figures? It didn't come from the top end.
I'll tell you something. If we were to put the X4 cylinder heads on a conventional engine we would be lucky to get a BSFC figure of 315g/kW-h or 26% efficiency. So let's rule out the top end as far as a contributor to the higher efficiency. The engine is port fuel injected like most vehicles so we can rule out the fuel system. Our intake and exhaust system is nothing special so we can rule that out. What is left? The bottom end which is our technology.

Originally Posted by hightower99

I will agree that part of the lower BMEP was top end design but didn't you achieve better than this in another test? Also how can your output at your target BMEP be good?

If you can achieve a lower BMEP at any RPM range at a given output then the efficiency is greater. Let's say, If you are able to lower the average pressure in a cylinder and increase the transfer of that force to the output shaft then the output of the engine will be the same. Lower pressure in the cylinder is a result of less throttle opening and less fuel used.

Originally Posted by hightower99

I am fully aware that this engine was not designed with high specific output in mind, also this report is not conclusive proof of revetec fuel efficiency superiority.

Well before you enter further into this view, post a BSFC figure of the most efficient petrol engine you can find on the internet or any other source and quote where you got the figure from. The best conventional engine I could find has a BSFC figure of 245g/kW-h and the best I could find on any engine was a non-certified figure on the quasi turbine engine which they stated was tested at a BSFC of 225g/kW-h. A good automotive engine can have a BSFC figure of around 270g/kW-h or 30.3% efficiency.

Originally Posted by hightower99

I think you meant to write "disproved" but maybe that was a freudian slip Who said I was finished arguing BSFC? as of yet you have data for a single RPM point and a single load (that where any good)... so what? Show me a full RPM and load range graph and that would be closer to proving any gains.

The 2,000rpm point was measured as it is an RPM point that most engine manufacturers test at. The reason...This is the point that most of the time an engine operates in/through. Cruising on the highway and accelerating economically in city driving.

Originally Posted by hightower99

There you go again completely missing the point... Why are you suddenly comparing an aviation engine to your previous design? I thought the RHL4 was designed for automotive use (you put it in a car remember?) Also where is this "double the output" coming from. The UL260i is comparable to the X4 because it is a 2VPC 4 cylinder aviation engine of roughly the same displacement. It is one of the engines that the X4V2 will be competing with if it comes out on the market. As far as I can see it doesn't have that much to offer (a single highly efficient operating point is about it).

You were talking about outright performance. I was just showing you that by adopting an already developed cylinder head that we can produce more power. At 3,300rpm the four valves do little in the breathing area, rather than it increases performance in the higher RPM ranges.

Originally Posted by hightower99

So your previous design got better specific power... Does that mean you are going backwards? or maybe this comparison is just flawed.

Hahahha...God you go on....We had limited time/budget to build the X4 engine and we do not have rapid prototyping and/or could source single cylinder heads with a bore of 108mm to adapt to our X4 design. The only solution in the 4 week time frame was to spend two weeks designing and two weeks to manufacture the two piece water cooled heads out of billet. This results in design limitations which did not allow us to design an optimum head. Again, no CFD or flow testing was performed due to time constraints and we know the cylinder heads are no where near optimal.

Originally Posted by hightower99

When the X4V2 comes out on the market for aviation engines what exactly is it going to offer over the alternatives?

Mainly the features that the aviation market are looking for is a compact/light liquid cooled (less cold shock to cylinder on decent) engine that is more efficient at 75% loading, providing greater travel distance per tank fill.

Originally Posted by hightower99

Don't just say it is more efficient and point out the single point that was tested. You need at the very least a part-throttle full RPM range average to make any big claims (increased bottom end efficiency).

Part throttle efficiency will increase with combustion chamber design including the correct amount of squish and combustion turbulence. This also includes some degree of swirl porting on the intake. This will be our next round of testing with Orbital. The current tests were performed to evaluate two things. Firstly the efficiency at the 2,000rpm 75% loading point, and to analyze other operational range data, to evaluated the level of top end development required from now on. This is our base line data to work from.

You're not going to say a BSFC of 207g/kW-h is good are you?

[hightower99]

Originally Posted by Matra et Alpine

Brain slip on you. Brad said he'll PROVE reliability

(it would be disprove of UNreliability, but that's very bad English )

Actually I was refering to the word "proved" from this quote from revetec:

Originally Posted by revetec

So I've proved time and time again your arguments against the engine and now we have top BSFC figures you've decided to now argue outright performance?

That is where I think he meant to write "disproved" hence the reference to a freudian slip.

Originally Posted by Matra

BTW, how are your engine design/builds going ? Keep looking for the thread on it so it can be discussed ......

Still in the design phase trying to get everything to work together the way I want it to as well as trying to simplify things. I have started looking at different materials and tools that I could use to make my first prototype of the engine. I have already said that I am not going to discuss the design much on the internet until after I have a good patent protecting it.

[revetec]

hightower99:

Remember, this is only our first independent certified test. A BSFC of 207g/kW-h will only be improved on from this point and we will increase efficiency in other operational ranges for our next test. Also I can remember you saying that a BSFC figure of 213g/kW-h would be good. We beat that in our first repeatable test.

You are right...I did meant "disproved" This is probably due to the fact that I have been reading/responding to you mainly at 5-6am "my time". This is why I go back at a later time and edit my responses due to typo errors. Sorry everyone. My brain is not up to full speed this early in the morning.

[revetec]

Originally Posted by hightower99

I have already said that I am not going to discuss the design much on the internet until after I have a good patent protecting it.

Good move. Too many people try to steal ideas these days. Apply for your patent before showing anyone or even discussing it.

If you need to discuss the patent procedure and schedule of payments and the capital required PM me. Your patent attorney will not give you the full picture of expenses, as they want you to apply ASAP so they have you nailed. You need to know how much money and when you need it so you can make sure you have it.

[hightower99]

Originally Posted by revetec

2,000rpm, 450kpa BMEP, best BSFC 207g/kW-h
So how did we get such good fuel efficiency figures? It didn't come from the top end.

With only that single point it could be almost anything. Maybe at 2000RPM and 450kPa BMEP several variables come together to achieve the great BSFC. You can't tell me that it could have only been the bottom end design.

Originally Posted by revetec

I'll tell you something. If we were to put the X4 cylinder heads on a conventional engine we would be lucky to get a BSFC figure of 315g/kW-h or 26% efficiency.

How do you know? have you tried? If you did something like that it would be going in the right direction towards proving any advantage from your bottom end.

Originally Posted by revetec

The engine is port fuel injected like most vehicles so we can rule out the fuel system. Our intake and exhaust system is nothing special so we can rule that out. What is left? The bottom end which is our technology.

That is a highly simplistic list of variables. What about any synergy that exists in the system? What about all the variables like bore:stroke ratio, cam characteristics, oiling system, maybe the clearances in all the bearings in the engine approach absolutely perfect? My point is that because you only have the single point you cannot make any conclusions other than it is possible to achieve that efficiency with that engine under those very specific circumstances. If the bottom end is the major contributer to the fuel efficiency then your engine should be more efficient all the time. This is what you have to prove.

Originally Posted by revetec

If you can achieve a lower BMEP at any RPM range at a given output then the efficiency is greater. Let's say, If you are able to lower the average pressure in a cylinder and increase the transfer of that force to the output shaft then the output of the engine will be the same. Lower pressure in the cylinder is a result of less throttle opening and less fuel used.

BMEP =/= Avg. cyl. pressure. BMEP is normally calculated from torque being a function of torque and displacement. Therefore if you have a lower BMEP value and the displacement is the same then output must also be lower(for any given RPM because the torque is lower). Maybe you are actually talking about average cylinder pressure and not BMEP.

Originally Posted by revetec

Well before you enter further into this view, post a BSFC figure of the most efficient petrol engine you can find on the internet or any other source and quote where you got the figure from. The best conventional engine I could find has a BSFC figure of 245g/kW-h and the best I could find on any engine was a non-certified figure on the quasi turbine engine which they stated was tested at a BSFC of 225g/kW-h. A good automotive engine can have a BSFC figure of around 270g/kW-h or 30.3% efficiency.

I haven't been able to find much but there isn't much out there anyways. What I need to counter you is a single point where an engine produces similar (Gasp! maybe even better) BSFC ratings and I can't find that on the www.

Originally Posted by revete

The 2,000rpm point was measured as it is an RPM point that most engine manufacturers test at. The reason...This is the point that most of the time an engine operates in/through. Cruising on the highway and accelerating economically in city driving.

I certainly don't spend the majority of time at 2000RPM, besides isn't this an aviation engine? My point was you should make a full BSFC map for the whole rev range and most loads. This allows everyone to see that the engine is always going to be more efficient and that it isn't just a lucky setup.

[hightower99]

Originally Posted by revetec

Remember, this is only our first independent certified test. A BSFC of 207g/kW-h will only be improved on from this point and we will increase efficiency in other operational ranges for our next test. Also I can remember you saying that a BSFC figure of 213g/kW-h would be good. We beat that in our first repeatable test.

Maybe I am being too subtle?


Congratulations on producing the extremely excellent figure of 207g/kWh and doing so in repeated testing!

[revetec]

Originally Posted by hightower99

With only that single point it could be almost anything. Maybe at 2000RPM and 450kPa BMEP several variables come together to achieve the great BSFC. You can't tell me that it could have only been the bottom end design.

No one quotes their worst BSFC, only their best.

From comments made by the test engineer. I also took a blank head in to show them the design. He then brought in a head to show me how it should be done.

Originally Posted by hightower99

That is a highly simplistic list of variables. What about any synergy that exists in the system? What about all the variables like bore:stroke ratio, cam characteristics, oiling system, maybe the clearances in all the bearings in the engine approach absolutely perfect?

Are you saying that all engine manufacturers have got it so wrong in the areas you have identified?

Originally Posted by hightower99

BMEP =/= Avg. cyl. pressure. BMEP is normally calculated from torque being a function of torque and displacement. Therefore if you have a lower BMEP value and the displacement is the same then output must also be lower(for any given RPM because the torque is lower). Maybe you are actually talking about average cylinder pressure and not BMEP.

This is what I thought and conveyed this to Orbital. I was looking for a higher BMEP. They said that at any given output, the lower the figure the better.

Originally Posted by hightower99

I haven't been able to find much but there isn't much out there anyways. What I need to counter you is a single point where an engine produces similar (Gasp! maybe even better) BSFC ratings and I can't find that on the www.

I certainly don't spend the majority of time at 2000RPM, besides isn't this an aviation engine? My point was you should make a full BSFC map for the whole rev range and most loads. This allows everyone to see that the engine is always going to be more efficient and that it isn't just a lucky setup.

A lucky set up? hehehehe. You don't think after 100 years of conventional engine development that if it was a lucky set up that it would have been done before?

It is an aviation engine, but this doesn't mean that we are not pitching to auto manufacturers. We are. Automotive is our biggest potential market. Everyone we have talked to in this market state they are looking for lower BSFC figures. The full BSFC map will be done during final optimization of the top end. I'm sorry but this is a bit of a process to optimize and you'll have to wait until our next independent testing procedure occurs.

So you don't drive on the freeway often?

[revetec]

Originally Posted by hightower99

Maybe I am being too subtle?

Congratulations on producing the extremely excellent figure of 207g/kWh and doing so in repeated testing!

Well in repeated testing we averaged 212g/kW-h, 207g/kW-h was our best, but thanks for the comment and recognition.

Cheers