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

[pneumatic]

So the question becomes, why are the power and torque figures from the revetec so crap?

I'm guessing the horrible mechanical inefficiencies of the design.

One problem is the balancing as you've already been told but won't listen to. The opposing pistons are tied together. They move as one in the same direction, so will make horrible vibrations.

And people that say a conventional boxer engine is perfectly balanced is on drugs. Their cylinders do not directly oppose, they are offset. So they don't balance each other.

And people say it's a simple design??? It's got more parts than a conventional engine. Look below;


The shaft through the center is the output shaft. The first and last tri-lobe is fixed to the output shaft, and so is the helical gear on the end (on the left in the pic).

The center gear is connected to another shaft, which is a sleeved outer shaft that fits over the inner main output shaft. But it isn't even a direct connection, there is planetary gears hiding in the middle there. This is because the gear on the left drives the shaft down the bottom, which then drives the gear in the center. But you want the inner two lobes (which are connected to the inner planetary gears and therefore center gear) to be going the opposite way to the outer lobes. So the planetaries are required to reverse that rotation direction. You might need to think about this a bit to understand.

So in order to get the crank mechanism to work, you need two big gears, two little gears, and an unspecified number of planetary gears. This is rather complex, and I am sure quite inefficient from a friction loss point of view. This is sure a lot more complicated than a conventional engine which has only a crankshaft and a conrod to do the same thing.

[pneumatic]

Originally Posted by clutch-monkey

so basically it's competitive against similar sized car engines but redundant because bike engines do the same thing but much better?

No, it's not competitive against similar sized car engines, because it has to work 3 times harder to do the same thing, and use 3 times as much air, and therefore 3 times as much fuel.

[fpv_gtho]

Why does your argument sound like its coming from an industrial competitor?

[pneumatic]

oh, and if you look at this;


and then look at this;


Now I am sure there are better pics out there, but that shows that the revetec engine is in fact running Subaru EJ20 / EJ25 cylinder heads, complete with factory oil filler.

So their 1.38L engine is running cylinder heads from a 2L conventional engine, but is supposed to be much smaller than conventional engines??? Doesn't look like it from that picture.

[pneumatic]

I'm by no means an industrial competitor.

I did however write this spreadsheet;
http://autos.groups.yahoo.com/group/exceldyno/

and therefore am probably more qualified than most to talk about torque, horsepower, rpm and the effects on acceleration.

[kigango123]

there have been so many concepts, quasiturbine, carnot cycle engines even the wankel this is just another trial and a poor one i might add

with this engine, the size or the surface area or volume to area ratio is inadequate, that means the engine will be heating the atmosphere not expanding
and what is this about increasing rpm to produce more power, sure it is done in f1 but it is extremely difficult to produce the same result in real life despite engine size, cbr motor at 600cc goes to 16,000 rpm, thats the best i have seen. this engine is better of being used as an oil pump or a personal vibrator rather than the current use

[pneumatic]

Originally Posted by pneumatic

Now they compare their relatively high performance engine (Haltech injection, custom made everything, probably individual throttle bodies) to a low performance production toyota engine.

I'll correct myself here, as I found the video of their 57kW 1.38L engine. It's not only using the 2-2.5L Subaru heads, it's also using the subaru intake manifold!



So that means their 1.38L is as wide as a 2L subaru motor.

The revetec is probably as tall as the subaru, maybe taller because they need the balance shaft below. The only space saving they could make is maybe in engine length, as they don't need to offset the cylinders like in a traditional boxer motor, but then they need the big gear on the back so it increases the length again anyway.

But then it gets stranger. You see the subaru intake is offset, for the offset cylinders. And the cylinder head cam gear is offset for the same reason. They appear to be using the offset intake and cylinder head drives, then they also must have offset pistons. So at the moment their prototype doesn't have directly opposing pistons, and therefore cannot be any shorter than the subaru motor anyway! In fact with the big gear in the way their motor must be longer.

Below is a pic from an EJ20T which I think they are probably using the manifold and head from. You'll notice revetec are just using the intake bolted on backwards to the throttle body sticks out the opposite end of the engine.


and don't get me started on a normal crank wasting all it's power at the start of the stroke where the crank angle is inefficient. Don't these people realise you have ignition timing that gets adjusted to ensure the cylinder pressures from combustion occur at the most efficient crank angles???

[pneumatic]

Originally Posted by richy33

You talk alot of crap for a person who knows nothing about revetec or its engines.

Not a particularly professional comment.

If you can explain the test data better than I have, and show me where I have made the incorrect assumptions, then please do so.

I didn't say the engine was doing 12,000rpm. I am saying the when the revetec engine is doing ~4,000rpm, the valve train and pistons were doing equivalent speeds to a conventional engine doing ~12,000rpm.

Therefore any torque and power figures from a revetec engine should be compared to a convential engine that is geared down 3:1.

If I am wrong than explain it to me. My observations on the pulley ratio's for the camshafts will be pretty hard to argue against. It's quite obvious what I say is true from simply looking at the photos.

[pneumatic]

My 3:1 observation is confirmed by the "let's torque theory.pdf" which is incorrectly linked on the Revetec website. They clearly stated;

When the power take off point is taken from the Primary shaft, power strokes occurring every 240degrees of driveshaft revolution as compared to a conventional RICE which has a power stroke every 720degrees, the CCE has 3 smaller power strokes per 2 revolutions equating to a conventional RICE having 1 large power stroke per 2 revolutions.

Where CCE is the revetec and RICE is a regular internal combustion engine.

That is what I and Stian have been saying. On a normal engine you make power every 2 turns of the crank, the piston goes up and down every turn. But with the Revetec has 3 lobes, so the piston goes up and down every 1/3 turn. It therefore makes power every 2/3 of a turn. Therefore it's internals (piston and valve train) are running 3 x faster than those of a normal engine.

So don't try to argue that, the revetec website even says it.

Even the leap report says the engine produces 6 power strokes per revolution. This compares to 2 power strokes per revolution for an equivalent conventional 4 cylinder engine. This is more proof the internals are running 3:1.

[pneumatic]

Originally Posted by richy33

You do not times the rpm by three, the gearing is made so that the output shaft runs 3:2 so if the output shaft is running 4120rpm, the internals are running about 2746rpm.

If this is true than it explains how your getting the subaru valve train to survive such relatively high revs.

If it is true, then Revetec is gearing it up 3:2 to try to get a usable rev range out of it. This means the internals will be effectively geared 2:1 rather than 3:1.

So at an output shaft speed of 4120rpm, the main trilobe shaft is doing 2746rpm (as you have stated). But the pistons are going up and down 3 times more than a conventional engine, so the valve train and pistons are effectively seeing 8240rpm.

So if what you say is true I should be comparing this engine to a conventional engine geared down 2:1. Fine, let's look at that.

First you could compare the 1.38L Revetec vs a 1.3L Suzuki Hayabusa engine as is;

[pneumatic]

As you can see comparing them with the Hayabusa "ungeared" is not very far due to the much much higher rev range.

So if you add a 2:1 gear reduction to the Hayabusa then the rev ranges become comparible, and the power strokes per revolution of each engine should become the same. As you can see on the attached graph, the Hayabusa engine is so much better, there is no comparison at all. It has nearly double the power and double the torque.

[pneumatic]

I think this quote says it all;

"The first thing I did was go to Queensland Institute of Technology. I'd come up with the concept but I wanted someone else to verify what I was doing. I presented (the idea) to them and, first off, I said that I was going to increase the level of thermodynamic efficiency beyond 50 percent. They laughed at me. They laughed, so I said 'well, I'll prove it to you.'"

I went to QUT, and I know they get people come in there every year claiming they've got a new fantastic idea, so it's not surprising they laugh. No-one has "proved it to them" yet.

The revetec does have some interesting aspects to it's design, but it is also surrounded by intentionally misleading marketing.

[clutch-monkey]

Originally Posted by pneumatic

I went to QUT

UQ represent!

[revetec]

Revetec has ben under development for about ten years. At the moment we have not been interested in performance engines so let's refer our engine design to performance in regards to fuel economy. We have produced a very flat torque curve which provides great acceleration right through the range. Our engines have been tested by automotive companies overses and we have replicated this . Another thing is that the fuel consumption remains constant under full load right through the rev range which is not seen in any other engine in the world.

I'll get one thing straight right now. We do not release most of the information about our engine as we protect our technology. We have not disclosed our actual design and guiding system for the pistons. We have almost perfected the design and are currently building our next model which all engines in the future will be based on. We have drastically reduced the size of our engine and reduced the amount of components. We have had no problem with gearing. Because of our new piston guiding system, we have no problem with piston twist.

Our engines in the past have been strictly development engines. Every time we change the Trlobe cam design the balancing changes. This is why up to date we have not balanced any of our engines as it has not been required for the type of development work we have been carrying out. Our new engine is fully balanced. Our reciprocating mass is smaller than other engines of the same capacity, and our stroke is shorter reducing the mass required for balancing. We used the subaru heads on our last engine purely because they roughly suited our last engine layout and our next engine will use heads developed in-house.

I think that most people don't understand our engine due to the fact we have not released certain information. I'll tell everyone now that the cylinder heads are operating at the same speed as a conventional engine. ie. The pistons stroke 2 times (1Xup and 1Xdown) per output shaft revolution (the same as a conventional engine), so there is no overspeeding of the engine's top end. Please remember we have not released all engine features and operation information. You will all have to be a bit patient.

I'll also state now that the formulas that work out power and torque do not work on our engine so all of you engineers that are trying to work out figures for our engine, your standard engine calculations will not work. We have proved this to several large automotive manufacturers and the like plus the figures we get in actual testing verify this.

A development program is just that. Trialling different engine layouts to evaluate different design features. Trialling a new design always creates unforseen problems and failures which then steer the design into the correct layout. Failures are normal for a development program, as with every new design longer endurance testing takes place. We are now in a postion that our next engine is ready for the testing required by engine manufacturers to evaluate in performance, fuel economy and initial endurance testing. Every automotive manufacturer in each region has different operating enviroments. So each engine has to be tested and modified to reach those standards in each region. Say for instance that an engine in Australia is different from one in another country even though the car model is the same. This is why the final endurance testing is not done by us rather an by the automotive company evaluating the engine technology for production.

What I can say is that we are nearing the end of development that is required before production of our engine is performed.

Stay tuned to our website www.revetec.com over the coming months as soon we are going to release info about our new engine. We are very excited about it and it will suprise everone in the engine field. We have now lodged a new patent world wide on the new design.

I will check this forum time to time so if you have any questions please post them as I will try to answer them when I have time.

Cheers
Brad Howell-Smith

[revetec]

The comment about misleading marketing is incorrect. All marketing the company has released is acurate. We are not bound to release all information about our engine and for security of our technology we reserve the right to hold back information. I have just returned from overseas where I presented to a board of about 8 senior engineers from a leading automotive supplier and the statement from them was "this is a step up technology".

We have proven in actual testing our flat torque curve and a flat fuel usage over a varying rev range. This has been done by a leading automtive company in their facility, fully independantly. I know many of you out there have a lot of questions because you don't have the full picture about what we are doing and I hope to disclose the rest of the information soon. I can say that we have presented to many of the world's top engine manufacturers including 2 Japanese car manufacturers and we have been able to satisfy all their questions posed to us. This technology is hard for them to comprehend so I don't expect you all here to understand what we are doing from the limited information.

As regards to the 1.3L Suzuki Hayabusa engine. Outright performance is not what this is all about. This engine is all about saving fuel by providing consistant torque throughout the rev range reducing the need to rev an engine into the higher power and rev range. By doing this fuel consumption is reduced dramatically. No doubt performance models will evolve to exceed conventional engines in the performance area. I know most of you are interested in the perforance area but I'll tell you now that that is not where most of the market sits. The current engines are directed at markets where fuel usage and pollution problems exist.

Regards
Brad Howell-Smith