Low Cost Gas Engine Innovation Doubles Fuel Economy
Revetec, a little known company from the Gold Coast region of Australia, may be on to something huge: they’ve created an engine that is 50% smaller, 50% lighter, has 50% lower emissions and is cheaper to manufacture than a conventional internal combustion engine of the same horsepower. Oh yeah, did I mention that it doubles the fuel economy too.
What that means is a car like the 2007 Toyota Yaris, which is rated at 40 mpg on the highway, would get 80 mpg with a Revetec engine.
This isn’t some hoax… They have a prototype which has been attached to an actual vehicle and independently tested to substantiate their claims.
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In personal communication with Mr. Brad Howell-Smith, the Chairman, Inventor and CAD Designer for Revetec, he says “road tests have estimated that [the engine] uses around 50% less fuel than a conventional engine” and if it were converted to run on diesel, that performance gain could be much higher.
Also, because the engine delivers higher torque, and can perform and operate well at much lower rpm’s than a conventional one, the noise levels are lower.
To illustrate how serious he is, Mr. Howell-Smith said that since 2001 his company has been in touch with the US Military Head of R&D for the Southern Hemisphere on a “regular basis” for the purpose of developing one of their engines for light aircraft.
The current prototype engine, the X4v2, is what Revetec calls a “controlled combustion engine.” The meat of the engine comprises two counter rotating multilobate cams, which are acted upon by two pairs of diametrically opposed pistons which are rigidly interlinked by connecting rods.
If that sounds like complete gibberish to you, you’re not alone. Which is why I included an animation of the process to the left. A more simplified animation of the general motion of an engine of this sort is also included below.
Mr. Howell-Smith said that “if [the engine] uses 50% less fuel given that it has the same top end as a conventional engine, emissions would be reduced by 50% if the bottom end was utilized.”
What does all that stuff about “bottom end” and “top end” mean? The X4v2 has a huge amount of torque over a much larger range of rpm’s than a conventional internal combustion engine.
If a person were to drive a vehicle fitted with this engine in a non-aggressive fashion and keep the rpm’s at the “bottom end” (meaning no “jack-rabbit” starts) they could expect to see a 50% reduction in emissions.
Alternatively, according to Mr. Howell-Smith, a person could see a 30% reduction in fuel use and a 30% reduction in emissions if they used the full acceleration power of the X4v2 all the time. This would provide a 20% increase in acceleration capabilities.
We could debate about whether or not the internal combustion engine has a place in the future of transportation or whether it’s going to be all-electric or fuel cell or whatever… but in the meantime, Revetec has a product that could revolutionize the the transportation industry now, and provide a much needed large reduction in fuel consumption and emissions.
Just imagine a bunch of 80 mpg Toyota Yarises (Yarisi??) running around all over the place. A little scary, I know, but… an 80 mpg conventional automobile? I must be dreaming, wake me up before I get too excited.
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Image Credits: Revetec
It’s mechanically fascinating, but, thermodynamically, where’s the claimed efficiency to come from?
Gober,
I think Ronald Orr said “In place of the usual crankshaft” not camshaft
2/10
Must try harder. Pay attention at the back please!
If it has increased dwell at TDC, it could be better than a crank and rod.
The Orbital test report was very surprising, the Revetec
seems to be much better than I would have thought.
I coined the trademarked name “Revtech” for Custom Chrome’s answer to Harley’s “Screamin’ Eagle” line ‘91.
To me this engine looks like it follows the principle of the Bourke engine. The idea there was to hold the piston at TDC longer and utilizing the hydrogen component of the fuel. This is where the efficiency of the engine can go from 30% to 60+%. I didn’t see anything said about the operating temperature either engine cooling or EGT. The Bourke engine runs cool, thus less wasted energy. The cam profile operating the connecting rod provides much more control over the combustion cycle, thus providing a way to optimize the engines performance. This looks like it would be more robust than the English Yoke of the Bourke Engine.
@sanjosemike - Ever heard of electrolysis? Look it up in Wikipedia…nuklear reactors are hardly required to generate hydrogen.
And for all those hydrogen nay-sayers…it may indeed take more electricity to generate hydrogen then what may be considered “efficient”. However, a hydrogen-powered engine is MUCH lighter then a comperable battery-powered engine would be(taking fuel tanks vs batteries into consideration. Not only that, but electric motors have VERY poor torque and poor performance at high speeds, often generating damaging sparks/arcs of electricity between components and generating a lot of unusable/wasted heat in the process.
Now actually on-topic…this engine looks interesting to me. Interesting, but worrisome. I also have engineering degrees(yes, as in plural), and mechanically/thermodynamically speaking this engine does not look very efficient. As has been stated before, there is a lot of mass moving around–which would cause a lot of vibration with just 4 cylinders…vibrations and gyroscopic twisting, putting added stress on the driveshaft. A V8 or V12 configuration it might be more efficient in this aspect. Additionally, I’m sceptical of this engines ability to perform over prolonged periods of time. The counter-rotating cam concept is interesting, but as with Rotary Engines, there is a lot of unnecessary surface contact. Surface contact = greater friction and wear/tear on components. Sure it looks good in theory, and on paper should be more efficient…but I doubt its realistic performing ability.
If the VW Luppo can get 80 mpg, this Revetec engine in a Luppo can get 160 mpg.
The design is sound in eliminating the heavy, space consuming, power sapping crankshaft. The engine is light and small and the power/weight ratio of a vehicle engine is very important as the vehicle has to cart around its own weight.
The piston is double ended with a normal 4-stoke combustion chamber/valves at each end, with the power take-off in the centre of the piston - in effect a two-stroke. But as these cam lobes can be three or five, or whatever, shaped, meaning the stroking per rev of the output shaft can be designed to suit applications. Put a 2-stroke arrangement at the end of each piston and this design is a real winner. 2-stroke inefficiencies have virtually gone to what they were 20 years ago. Orbital in Australia and Chrysler did some intensive research into this and came out wit the goods with major makers ready to produce with factories tooled up ready - but never when they found the Japanese were not going to introduce a 2-stoke for cars - sop back to the status quo. The Chrysler Neon car was designed to take a 2-stoke engine and 2-stoke prototypes run in the car before launch.
What does all this mean? It is the knock-on effects that makes this engine a winner. It means a vehicle:
1. Need not have a power sapping, heavy transmission as torque can be given at the require levels.
2. Can have a smaller engine lower bay.
3. Can be lighter.
4. Better air resistance as the car body designer has a freer hand in air resistance.
5. More passenger/luggage carrying capacity for no larger a vehicle.
6. Using a 2-stoke arrangement at the piston top-ends, the efficiency, which cascades into mpg and emissions, rises substantially.
7. Less moving parts in the engine mean more reliability.
8. Less moving parts means longer service intervals.
These people are going the right way. Look at the electric Mini:
http://www.treehugger.com/files/2006/08/the_hybrid_mini.php
http://www.pmlflightlink.com/archive/news_mini.html
Put one of these small, light, efficient Revetec engines as the genny for the electric Mini and maybe a real winner.
They can clearly be used in hybrids to great success, say using the Toyota hybrid system, which is clearly the best of the bunch.
The main auto makers will not take up the Revetec as they would need to pay royalties. If they did not have too, they may be looking into the this design. If it takes off by a small manufacturers and may a Malaysia company uses it, then the others will have to follow, if they have not introduced electric by then, as battery technology improves.
The Revetec may keep the Internal combustion engine going for longer - a design that should have been cast into history over 50 years ago.
Thats cool, sort of like a combination of Wankel/rotary and conventional engines. The wankel is a neat design but fuel consumption is a problem.
an X8 (or X4v2 in the diagram).. good marketing, I mean an X8 is gotta be better than a V8…dude !
Over more recent years nobody has really changed the bottom end arrangements, in mass production (Wankel excepted) but there are variations going back a few more years, eg; a cut-away swash plate engine was in the London science museum back in 1962 or 4 when I saw it .. my dad was impressed anyway. this is an angled disk/plate on the crank that the piston pushes up against; its like when a screwdriver is pressed hard on a dinner plate and the thing whizzes off to the side or spins (or breaks) http://en.wikipedia.org/wiki/Swashplate_engine
A nice feature of the swash plate engine is that its all in-line, very good for aircraft engines.
There was a model aircraft engine that used a sort of dogleg conrod to connect a piston/cylinder in line and over the crankshaft, it was practical, mass produced but expensive; circa 1960, Aero35 I think.
I dont know how the X4v2 can be made cheaper, I see a lot of bearings and precision machined parts replacing the humble conrod + I dont get that the bearing under the piston would be a ball bearing (I think that it would be a plain bearing ?).
I think wear could be a problem, all those precision bearings and cams, recip weight, so any play or ignition error (pinking etc) would blow the thing up….
Low revs makes sense, there is quite a lot of reciprocating weight (but balanced). They could save costs by not having such extream/expensive emmision control stuff.
The thing that is puzzling is the reason for it getting 50% better fuel economy with the same top end as a conventional engine. I guess that the power from the piston going down is much better matched to the crank than a simple conrod linkage; because of that drive cam. Still… if one can better control the combustion to match the conventional conrod-crank load then that would be nice; but thats probably what everyone has been doing the past x years….
It would look cool on a Harley tho, would that be an X2 ?? (ok I2) rubber mounted of course !
“Thats cool, sort of like a combination of Wankel/rotary and conventional engines.”
It is a reciprocating piston engine and nothing like a rotary Wankel.
“I think wear could be a problem, all those precision bearings and cams,”
Two cam lobes and few rollers that’s all. High quality hardened metal can be used on the cam lobes and rollers. The cylinder bores will last and last as there is no piston side thrust
“there is quite a lot of reciprocating weight ”
Not so. The opposed pistons are all one unit (a double ended piston) with a cut out in the middle for the take off to the cam lobe. The cam lobes are not reciprocating.
The conventional con-rod swivels at both ends which is far from ideal - in fact a liability. The Revetec has cracked it. Once introduced, many years after much fine tuning would be done improving the unit substantially. Many variations would emerge too.
However I am glad eclectic cars will push it into the background for vehicles as a genny or whatever. It has uses other than vehicles: pumps, portable gennys, marine, etc.
The cam lobe mechanism shows much promise in a Stirling engine unit.
Highly tuned to power in-wheel hub electric motors with a battery buffer in between. A hybrid. Powerful enough to drive the vehicle normally via the electric motors, when the battery does not have enough charge. Cutting out when the battery is charged enough going onto full electric drive. That means when not on full power driving the car, the engine can be revving higher to charge the batteries as well. Using the fast charge Toshiba batteries would be a good match.
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HOW DO I CONTACT THIS COMPANY REVTEC ??
MAHALO