Seals were a major problem in Wankel rotaries in 1970's-1980's. In the Mazda rotaries, a great running , fun engine, at peak of development in the early 1980's when I fooled with them, they still had to inject lube oil into the combustion chambers to keep the tip and side seals alive. The resulting oil smoke emissions were causing the Wankels problems meeting ever more stringent emission laws in the USA. That is ultimately what killed rotaries for production cars.

Seals for the engine in the article will have exactly the same issues, and will probably have the same emission problems from the need for oil injection.

Cost of special machining for the cycloidal / epitrochoidal combustion chambers during manufacturing and the special coatings/platings in the combustion chambers increased costs to the point for Mazda where a tuned 4 cyl or 6 cyl conventional engine was cheaper to make.

The two lobed rotor and three lobed chambers shown in the article are nothing new. NSU and Wankel developed many odd chamber geometries in the 1950's and 1960's . There is nothing new under the sun.

I suspect the article is hype for something that will not ultimately be any kind of breakthrough, just a sink for investors' money.

If I were investing in car development (I'm not, by the way) I would look to developers of better battery technology for electric cars. Motor designs are now mature enough (see Tesla cars) but range and life of batteries are the major limiting factors in acceptance of electric cars in USA. The company that can make a battery/car with 1500 km range at 100 km/h vehicle speed and sell it for $25000 USD will be a big success.

Would like to see a computer animation of how it works – are there any out there? I haven't found one yet.

John

There is a link to there site which has this video animation

**LINK**

Watching full screen the chamber seems to change size but if they have cracked that aspect I doubt if they would want every one to know how. It gives the impression that the "tips" are stationary.These look a bit weird in the video too.

Mazda when they were selling them just kept repairing the engines for customers. I did know some figures but they have departed my grey matter probably because they were nothing short of mad.

I worked on electric vehicles for some time. The volume and weight energy density Jeff wants would need Dr Who's Tardis technology and if it's still heavy zero energy anti gravity. I'm not sure about the weight of the Tardis. What might happen is quick change battery packs but somehow I don't think any current battery technology could work that well even then. All forms tend to be a pain if they are flattened too much for one thing and they can't be got going again with a 5L can of fuel. One of the problems is voltage. To keep the current levels low the volts need to be high which in turn needs loads of cells in series which mean oh dear and all sorts of problems keeping each cell perfectly topped up – that's what they need because if some aren't they will flatten before the others do. Some charging up before others tends to prevent the flatter ones from fully charging too – an electronic/electrical nightmare when I saw solutions and probably still is.

Hybrids are more feasible really and gain because the engine runs over a much more restricted regime so can be a lot more efficient. Talking to some one who owns one it seems that they don't own the battery pack. Interesting if true. As I am also a bit of a software buff I spent some time modelling hybrids for Fiat and others. They did seem to offer a gain even what, 20 odd years ago. Electric vehicles going from production of the electricity to the results on the road was not so clear – dubious really.

I have seen some spectacular batteries. One of instance would replace a car battery and could easily be held in one hand. Cost of the materials was pretty extreme and in terms of deeply discharging them torpedoes and ballistic missiles etc are a bit one shot.

Fuel cells might be the answer one day – they need fuel.

John

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Edited By Ajohnw on 12/01/2016 17:37:54

Out of curiosity and to put what seems to be the latest wonder couple for use in batteries diesel gives over 13,000 wh/kg.

Liquid hydrogen or the gas which has it's problems around 3 times as much. Metal hydrides are much safer and no figures for those.

Numbers from the wiki via a web converter as they were in Mj. Joules are an unknown for me as never used them for this anyway.

John

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When I worked at a major automotive consultancy, we saw loads of these fantastically efficient new engines coming from all corers of the earth. Every possible concept, all claiming to be THE breakthrough. Generally the concept needs to promise be slightly more efficient than what is currently on the market but of course the same laws of thermo continue to apply (despite their claims).

But the laws of fund raising also apply – oversell, exaggerate, prise endless rounds of funding from investors, spend some of that on smoke and mirrors – and don't forget to make a few demo engines and vehicles that appear to show progress towards the end goal. Finally, find an even bigger set of mugs to sell the company too. That's the end goal that the investors are excited about. They know that the returns would be very big IF it all comes off. They also know that many of these speculative investments will fail. And nobody who is part of it will admit readily that perhaps it was never going to work.

Whether or not you make it to that last stage and whether or not you find said mugs, it pays you along the way. And you develop a reputation as a safe pair of hands in this "innovation" space. So you can start all over again.

It's a well-trodden path!

The downfall of the Wankel, and probably of any similar design, is that the combustion shape is very poor. This means that there is a lot of loss of heat directly into the metal, giving poor fuel economy. So they end up being a bit like the two stroke engines in motorbikes…compact, powerful, smooth, and very thirsty.

Swash plate engines like Vic shows are certainly workable, but there tends to be more friction in the swash plate arrangement than in a crank, so unless space is at a premium like in a torpedo, they are not likely to offer any advantage.

The really successful rotary engine is the gas turbine.

John

The skill is to trumpet some astounding number taken from a best case condition on a sunny day with the wind behind, with significant experimental error conveniently (and possibly cynically) on your side. Then allow the audience to think that it will achieve this under all conditions.

I wasn't even working directly in engines – I was responsible for helping clients to develop electric and hybrid vehicle systems and components. As you might expect, there are plenty of charlatans there too, claiming to have astounding battery / motor / converter concepts. However, as ever the laws of physics tend to prevail. For instance, the torque and power a motor can produce are a fairly simple function of the flux generated across a gap between two surfaces. Given the saturation flux of steel and the available active surface, no number of genii and PhDs will produce any dramatically superior motor. Similarly, even the cleverest battery chemistry can't get around the limit to the amount of chemical energy you can store in a battery. But venture capitalists aren't technical.

The US seems to be a particularly good place for people like this to operate. Partly due to the lax, almost non-existent concern for advertising standards and the thrusting MBA culture that is so often prevalent in businesses there. Makes the world a more interesting place though!