Rotary engine maker looks for clean-tech traction

By Lou Whiteman
The Deal.com
Published: December 7, 2006, 11:34 AM PST

John Robertson has spent more than a decade perfecting an engine his boosters claim could mark the death of the piston. He will know soon whether it was time well spent.

Robertson's Reg Technologies is building a lightweight, clean-burning new engine technology capable of running on fuels ranging from diesel to hydrogen.

The engine is an offshoot of the rotary design, which replaces the reciprocating motion of the piston with a single rotor that moves around an oval chamber. The design is significantly smaller and more lightweight than a typical piston engine, giving it more push per pound. And because it has fewer moving parts (13, compared with 40 on a piston) and operates in a smooth motion, advocates claim it causes less strain and vibration and is therefore easier to maintain and repair.


Reg Tech's current design, dubbed RadMax, is the result of $11 million worth of research. The company plans to begin tests on its prototype 125 horsepower engine before year's end and hopes to have it ready for commercial use soon after.

Robertson is targeting military applications such as unmanned aerial vehicles first, confident that his lightweight design will allow craft to carry more fuel and stay aloft longer. The plan is to license the engine to truckmakers and then later perhaps to automakers.

"Change will not happen overnight," Robertson admits.

German engineer Felix Wankel introduced the engine concept in the mid-1950s, but despite drawing rave reviews for its power and simplicity, several drawbacks have relegated it to the fringes. Among automakers, Japan's Mazda has been the engine's principal champion, but today in the U.S., only the manufacturer's RX-8 sports car operates using the design. That car highlights the rotary's weaknesses: Mazda recommends owners check the oil frequently due to the engine's tendency to burn it.

Robertson asserts that his company's design makes major improvements that should solve many problems. If it works as promised, the RadMax would run on nearly any fuel, burn with little to no emissions and provide a new lighter-weight engine alternative for recharging battery cells on hybrid cars. Soon it may have its day in the sun.

Don't Mazda Wankel engines intentional burn some of their oil?

This is simply a new take on the 19th century swash-plate engine,except with flat vane seals instead of circular ones.

I predict the reciprocating mass of the seal vanes combined with diagonal stresses and sealing issues will be it's downfall.

http://www.regtech.com/directcharge.html

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Thanks for the link.

It looks like the thing could be ganged inline?

Issues of seals and thrust vectors have been haunting recip engines since their original design and it has taken a century of evolution to get to where we are -- perhaps approaching the end of recip evolution, given the constraints of fuel efficiency and pollution.

In the long run this (and other) rotary designs may offer no advantage to reciprocating engines. It's nice to see alternative designs still entering the market of ideas.

B

That Gif is a little off with combustion flashes but shows the basics of operation. Brilliant design.

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Satan creates nothing: he only ruins everything. He does not invent: he tampers. And his followers are no different ~ Archbishop Carlo Maria Vigaṇ

Yup. Some oil is constantly injected through the intake to lubricate the apex seals at the tips of the rotor(s).

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1985 380SE Blue/Blue - 230,000 miles
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i too am sceptical of its actual potential.

the seals sealing aginst the ramps have to seal at constantly varying angles. all seals i have seen seal with the seal (like a ring on a piston) perpendicular to the sealed surface at all times.

i just don't see how this will work.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

One great advantage of a rotary is its compatability with a wide range of fuels with unimpressive octane and cetane ratings. One great disadvantage of the rotary is fuel efficiency. A 1975 Mazda RX-4, tipping the scales at 2,800 lbs. and putting out a romping, stomping 140 HP, got 11 MPG City according to the EPA.

Thanks for explaining the seal issue. That makes a lot of sense.

What I like about the rotary idea (whether Wankel, turbine, or this creature) is that the mass is not in constant acceleration or deceleration. I admit it sounds silly, but the reciprocating mass thing just seems an inelegant solution to a problem requiring rotation.

This design appears to have more rotating mass than does either a turbine or a Wankel and delivers more ignitions per rotation than a Wankel? That looks to me like it should have better power/wt and better torque than a Wankel.

B

I just wonder why nobody has come up with a Wankel diesel engine...

Ive heard of wankel diesels. Let me see if I can find the website. The company is/was called Rotary Power International.



Edit: it seems the page no longer exists. All I could find is a pic of a Rolls Royce/wankel diesel

http://commons.wikimedia.org/wiki/Image:RR-R-6.jpg

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Satan creates nothing: he only ruins everything. He does not invent: he tampers. And his followers are no different ~ Archbishop Carlo Maria Vigaṇ

From wiki:
"Perhaps the most exotic use of the Wankel design is in the seat belt pretensioner system of the Volkswagen New Beetle. In this car, when deceleration sensors sense a potential crash, small explosive cartridges are triggered electrically and the resulting pressurized gas feeds into tiny Wankel engines which rotate to take up the slack in the seat belt systems, anchoring the driver and passengers firmly in the seat before any collision."

Mercedes also uses it (See pictures).

From the patent description:
"The motor 40 is not an internal combustion motor, although it is similar in construction to the known "Wankel" engine. Rather, the pressure of the fluid supplied by the pyrotechnic device 80 into the pressure chamber 48 results in movement of the rotor 42 and consequent rotation of the output shaft 66. There is no combustion or ignition within the motor 40, other than occurs upon the actuation of the pyrotechnic device 80. A passage 88, similar to the inlet port 85 and the exhaust port 86, enables fluid flow between the chamber portion marked 48a in FIG. 5D and the ambient atmosphere. Thus, there is no drag-inducing compression of fluid in the chamber portion 48a."

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