Could this be an engine to build ???

[Owen_N]

I have been a big fan of the Wankel rotary engine now for half my life. I have owned and driven a couple of Mazda RX7s and plan on cutting a 13B I have, in half to put in my late 70's Suzuki truck. For probably 2 decades I was on a fabulous news group dedicated to the development of rotary engines for use in aircraft. There are a lot of myths out there about the rotary. Initially there were problems getting the rotor apex seals to last an acceptable length of time but Mazda spent millions on the problem and solved the issues in the early seventies. But the myth lives on. A rotary will indeed run without seals but you won't realistically be able start it without them. If a rotary sits for an extended period an apex seal can stick making for a hard or non start, but it's easily dealt with by removing a couple of spark, squirting in a little transmission fluid and poking the apex seal.
A few of the main attractions of the Wankel for aircraft use are small size, power to weight ratio, high duty cycle, high power potential, stackability, incredibly smooth operation, very low parts count, no reciprocating forces and no valves. The time to climb record from a standing start to 15000' is held by a modified Mazda based rotary. One of the biggest hurdles to a successful implementation is the cooling system, it's not difficult but it has to be done correctly.
Just after the second war, aircraft engine builders looked at improving their large radial engines. Wright led the pack and went after the heat and pressure coming out the exhausts which is by far the greatest point of waste energy. They incorporated blow down turbines into this energy stream, 4 per engine I believe and they recovered 1200 hp if my memory serves me correctly. They used these engines in several military applications and on the Constellations which basically made the Atlantic a viable opportunity. The Achilles heel of this engine was, as with most aircraft engines the exhaust valve. It was a very common occurrence to arrive on the other side of the pond with at least one engine shut down. Then came jets. Of course the Wankel doesn't have valves.
Chevrolet, Ford, John Deere, Rolls Royce amongst others have all made Wankels and Rotax, Norton, OMC, Suzuki, Sachs, NSU have all had production models and of course Mazda has produced millions. If Mazda had mastered the Wankel at the same time that Otto developed the four stroke ICE then we would all, without a doubt, be driving rotary engines and scoffing at the idea of building reciprocating engines.

Rotary engines still have problems that Mazda seems to have felt to be uneconomic to fix:

1) generally less durable than modern piston engines.

2) Unhelpful combustion chamber shape. High surface to volume ratio, and the petrol versions seem to suffer from delayed burn.
Possibly a diesel version would work better. Is maximum CR a limitation for this?
The LP X-engine at least addresses the combustion chamber shape problem.

3) Burning standard engine oil with all its additives, at the rate it does can't be good for sparkplug life.
- a portion of the sump oil is sprayed into the combustion chamber to lubricate the tip seals.
A separate oiling system with two-stroke oil would be sensible, if not a "good look" for the buyers.

Mind you , all engines used to drink a fair bit of oil at one stage.
Oil economy is a bit of a new thing, since the 1960's?

4) difficulty of development for emissions control.

It could possibly be done, but it would be a huge research effort.

Over the many years of production, they didn't seem to make a lot of progress on economy and emissions.

Getting reasonable fuel economy and lower nitrogen oxides at the same time would be tricky.

 

[Steamchick]

Owen, you have hit the nail on the head. It is not the mechanics that have "killed" this engine as a main type, but economy and cleanliness. As with 2-strokes! (both cylinder ported and 4 strokes made to run a 2-stroke cycle -e.g. Atkinson, Toyota, et al..).
And as NOx and CO2 are killing most infernal combustion engines, we are trying to become a modern energy hungry society that does not use fossil fuel. I was taught at school that we would run out of food due to overpopulation of the planet (100 years) before we would run out of coal (300 years)... But that was before people realised that converting all that coal to CO2 would kill us all anyway! And that was in the days when it was thought that we would make coal obsolete due to nuclear fusion - later fission - power. Well, we are on that path by using the nuclear fusion in the sun as the "safe and reliable" source of all our power - wind and solar.... (at the moment). And who would have thought we are trying to fill or roads with cars full of the most volatile products in the universe, Hydrogen and lithium!? Ask the Japanese how to blow up 4 nuclear fission power stations? Fill them with sea water, and the lithium and hydrogen will blow them up for you!
Still, I reckon I'll be dead, or past riding - when the petrol runs out for my ageing Moto Guzzi... (1970s nostagia). I think of that as the start of the end for fossil fuel Bikes. Designed for economy (Heron head) rather than power.... following the 1974~'76 "fuel crisis" where fuel prices became exorbitant - and we nearly brought in ration books in the UK! - Inflation at 26% in June '74 as I recall? - Expect the same when they "ban petrol cars"...?
K2

K2

 

[Owen_N]

Owen, you have hit the nail on the head. It is not the mechanics that have "killed" this engine as a main type, but economy and cleanliness. As with 2-strokes! (both cylinder ported and 4 strokes made to run a 2-stroke cycle -e.g. Atkinson, Toyota, et al..).
And as NOx and CO2 are killing most infernal combustion engines, we are trying to become a modern energy hungry society that does not use fossil fuel. I was taught at school that we would run out of food due to overpopulation of the planet (100 years) before we would run out of coal (300 years)... But that was before people realised that converting all that coal to CO2 would kill us all anyway! And that was in the days when it was thought that we would make coal obsolete due to nuclear fusion - later fission - power. Well, we are on that path by using the nuclear fusion in the sun as the "safe and reliable" source of all our power - wind and solar.... (at the moment). And who would have thought we are trying to fill or roads with cars full of the most volatile products in the universe, Hydrogen and lithium!? Ask the Japanese how to blow up 4 nuclear fission power stations? Fill them with sea water, and the lithium and hydrogen will blow them up for you!
Still, I reckon I'll be dead, or past riding - when the petrol runs out for my ageing Moto Guzzi... (1970s nostagia). I think of that as the start of the end for fossil fuel Bikes. Designed for economy (Heron head) rather than power.... following the 1974~'76 "fuel crisis" where fuel prices became exorbitant - and we nearly brought in ration books in the UK! - Inflation at 26% in June '74 as I recall? - Expect the same when they "ban petrol cars"...?

I don't think internal combustion cars will be banned outright, but there may be "mandatory scrapping" at a certain age or "mileage", except for some preserved classics.
That could be a bit hard on retired people, or others who can't afford to upgrade.

Japan seems to be heading this way.
Older cars or damaged cars have a very stringent recertification process, that most owners don't bother with.

Also, new petrol/gasoline cars will be banned outright in 5-10 years at the most,
- which seems to be the case in the UK and most of Europe-
-no gasoline/petrol vehicles in city centers-
and possibly some special category vehicles will still be allowed, but not many.

Some people live well away from "civilisation" and may still have some range issues.

Service stations may die out if only 10 percent of remaining vehicles use them, which could start happening in 10-15 years?

Some people keep cars for 30+ years, but most cars made in the 1990s are now scrap.

Quite a few from 2000 - 2015 have been scrapped as well.

You then buy fuel in drums, and fill up yourself- no good if you park on the road and have no garage.

$100+ of fuel makes for a pretty heavy drum at say $2.40 NZD per litre.

Lower distribution will definitely also put the price up!

 

[ajoeiam]

I have been a big fan of the Wankel rotary engine now for half my life. I have owned and driven a couple of Mazda RX7s and plan on cutting a 13B I have, in half to put in my late 70's Suzuki truck. For probably 2 decades I was on a fabulous news group dedicated to the development of rotary engines for use in aircraft. There are a lot of myths out there about the rotary. Initially there were problems getting the rotor apex seals to last an acceptable length of time but Mazda spent millions on the problem and solved the issues in the early seventies. But the myth lives on. A rotary will indeed run without seals but you won't realistically be able start it without them. If a rotary sits for an extended period an apex seal can stick making for a hard or non start, but it's easily dealt with by removing a couple of spark, squirting in a little transmission fluid and poking the apex seal.
A few of the main attractions of the Wankel for aircraft use are small size, power to weight ratio, high duty cycle, high power potential, stackability, incredibly smooth operation, very low parts count, no reciprocating forces and no valves. The time to climb record from a standing start to 15000' is held by a modified Mazda based rotary. One of the biggest hurdles to a successful implementation is the cooling system, it's not difficult but it has to be done correctly.
Just after the second war, aircraft engine builders looked at improving their large radial engines. Wright led the pack and went after the heat and pressure coming out the exhausts which is by far the greatest point of waste energy. They incorporated blow down turbines into this energy stream, 4 per engine I believe and they recovered 1200 hp if my memory serves me correctly. They used these engines in several military applications and on the Constellations which basically made the Atlantic a viable opportunity. The Achilles heel of this engine was, as with most aircraft engines the exhaust valve. It was a very common occurrence to arrive on the other side of the pond with at least one engine shut down. Then came jets. Of course the Wankel doesn't have valves.
Chevrolet, Ford, John Deere, Rolls Royce amongst others have all made Wankels and Rotax, Norton, OMC, Suzuki, Sachs, NSU have all had production models and of course Mazda has produced millions. If Mazda had mastered the Wankel at the same time that Otto developed the four stroke ICE then we would all, without a doubt, be driving rotary engines and scoffing at the idea of building reciprocating engines.

Hmmmmmm - - - Knew a guy who had an RX-9 (IIRC - - bought in about 2006 or so brand new - - - -14k rpm - - - serious get up and go too!!!).

I've wondered about using 2 or 3 stages of a 'rotary engine' for steam power generation.

What say you?

(Lower T and likely less P on the seals - - - dunno about oil fouling of the steam though.)

 

[William May]

Sorry, but I read all the publicity data on this engine, and it is what I consider a "******** Engine". Lots of tech talk that means nothing, no prototype running, and if you look at the physics involved, it probably won't work anyway. They say they have a lot of patents on it. Just what SPECIFICALLY is patented? I would want to know what all the patents cover. I sincerely doubt they actually have found anything new.
GM, Ford, Chrysler, Packard, and even the Franklin Automobile Co, with their air-cooled engines, have spent BILLIONS over the years, with some of the most genuinely BRILLIANT engineers spending their entire careers on IC engines.

I don't care how brilliant this guy is, this engine, as an IC engine has no future.

Ford has already stopped production of IC engines. GM will not be building any more within 2 years. Jaguar is no longer building any IC engines as of this model year.

NO MODERN IC ENGINE IS GOING ANYWHERE AS OF RIGHT NOW.

You might as well have come up with a new, brilliant, patented buggy wheel for horse drawn vehicles.

But maybe, if they ACTUALLY get it to work, they can sell plans and casting kits on this forum, for the eccentric experimenters who will actually have an interest in building an obscure and impractical new breed of IC engine. I don't think any large manufacturing company has any interest in developing a new design of IC engine.
But I bet they WILL sell at least 50 sets of plans, and 10 casting kits to members here. That will probably be enough to cover the cost of ONE of their blurb ads in some publication.

This thing is 60 years too late.

 

[vederstein]

Ford hasn't stopped production of IC engines. They've stopped research and design on IC engines. Their current crop of engine designs is their last (unless market forces push otherwise).

I didn't watch the entire video, but I did watch the animations. Forget about this concept being practical. There's just too many surfaces to seal. You have the face of the rotors to the end plates. You have the rotor boss to the case bore. You have the sealing of the two interlocking rotors. You have heat expansion gradients all throughout this.

You also need to lubricate all these surfaces.

Technically possible? Yeah, probably so.

Economical to do? Hell no.

I believe sleeve valve engines dies because of excess oil consumption and they only need two sliding surfaces to seal. This thing has what looks like seven.

I always thought the six stroke diesel/steam scavenging engine had promise. It uses strokes five as a water injected flash steam power stroke and stroke six to exhaust the steam. No need for a cooling system because the steam cycle takes away the excess heat.

Old ideas become new again. Another company had a three cylinder gas engine. The exhaust from cylinders one and three are fed to cylinder two to create an additional power stroke in what would otherwise be waste heat. This is nothing more than a compound steam engine, but running a four stroke gas cycle.

There's also a company with a turbo & supercharged three cylinder opposed piston two cycle diesel that claim upwards of 60% thermal efficiency. (A typical gas engine is around 25-30%). They claim the opposed piston design optimizes the combustion chamber. It has no need for valves. Some of the thermal efficiency comes from not having heat loss though a cylinder head because this type of engine doesn't have one. Unlike these other designs, I think this one has a chance of success, particularly in off-grid power generation and heavy industry where opposed piston engines already have a foothold (e.g. locomotives).

There's all sorts of rotary/piston engine designs out there. Nearly all fail because our current crop of gas and diesel engines are quite effecient, reliable, and robust. There's simply too much risk out there to try a new engine design when as William May said, the internal combustion engine is nearing the end of it's 200 year life.

Yet, the steam engine, in the form of the steam turbine for electrical generation will continue to endure.

...Ved.

 

[William May]

Ford hasn't stopped production of IC engines. They've stopped research and design on IC engines. Their current crop of engine designs is their last (unless market forces push otherwise).

I didn't watch the entire video, but I did watch the animations. Forget about this concept being practical. There's just too many surfaces to seal. You have the face of the rotors to the end plates. You have the rotor boss to the case bore. You have the sealing of the two interlocking rotors. You have heat expansion gradients all throughout this.

You also need to lubricate all these surfaces.

Technically possible? Yeah, probably so.

Economical to do? Hell no.

I believe sleeve valve engines dies because of excess oil consumption and they only need two sliding surfaces to seal. This thing has what looks like seven.

I always thought the six stroke diesel/steam scavenging engine had promise. It uses strokes five as a water injected flash steam power stroke and stroke six to exhaust the steam. No need for a cooling system because the steam cycle takes away the excess heat.

Old ideas become new again. Another company had a three cylinder gas engine. The exhaust from cylinders one and three are fed to cylinder two to create an additional power stroke in what would otherwise be waste heat. This is nothing more than a compound steam engine, but running a four stroke gas cycle.

There's also a company with a turbo & supercharged three cylinder opposed piston two cycle diesel that claim upwards of 60% thermal efficiency. (A typical gas engine is around 25-30%). They claim the opposed piston design optimizes the combustion chamber. It has no need for valves. Some of the thermal efficiency comes from not having heat loss though a cylinder head because this type of engine doesn't have one. Unlike these other designs, I think this one has a chance of success, particularly in off-grid power generation and heavy industry where opposed piston engines already have a foothold (e.g. locomotives).

There's all sorts of rotary/piston engine designs out there. Nearly all fail because our current crop of gas and diesel engines are quite effecient, reliable, and robust. There's simply too much risk out there to try a new engine design when as William May said, the internal combustion engine is nearing the end of it's 200 year life.

Yet, the steam engine, in the form of the steam turbine for electrical generation will continue to endure.

...Ved.

I agree with most of your points. However, the sleeve valve engine is really an excellent engine. I am a member of the Willys-Knight registry, and until I joined that group (because I have two early Overlands, but they are NOT sleeve valve engines) I never even knew how a sleeve valve engine worked. However, there are members who have cutaway engines that you can crank and watch everything move, and it becomes abundantly clear why they are such a good engine. Because all the wear is spread over the entire sleeve assemblies (two sleeves for each cylinder, one intake and one exhaust) Their wear rate is EXTREMELY slow. Whereas other early engines suffered from carbon buildup and accumulations, the sleeve-valve engine actually seals better and runs quieter once it has some miles on it. According to the people who have these cars, the engines don't wear out, they wear in, better and better, for thousands of miles beyond what a normal engine would have as a lifetime. After I saw some of the vehicles, heard them run, and talked to the owners of the cars, I finally had a grasp of how good sleeve-valve engines are.
People were just unfamiliar with them, didn't understand how they could possibly work or be reliable, and so they only sold in small numbers. Also, unlike a Model T, the average owner could not tinker with their Willys-Knight engine. Timing of the sleeves was fairly critical.
As engine enthusiasts, if you ever are at a car show, and there is a Willys-Knight Sleeve Valve engine car there, be sure to talk to the owners. They are always very proud of their engines, and will talk your ear off about how good they are. (I had Industrial Heavy Duty Ears installed years ago when I knew my wife, so I have no problem handling Willys-Knight aficionados.) They may even have one of the cutaway engines that you can crank, as the factory produced several thousand of these demonstrators for dealers, and they are greatly sought after by Willys-Knight car owners. It is not a complete engine, but a section that can stand on a counter and show how sleeve-valves work, so they could be explained to customers.

 

[Richard Hed]

I agree with most of your points. However, the sleeve valve engine is really an excellent engine. I am a member of the Willys-Knight registry, and until I joined that group (because I have two early Overlands, but they are NOT sleeve valve engines) I never even knew how a sleeve valve engine worked. However, there are members who have cutaway engines that you can crank and watch everything move, and it becomes abundantly clear why they are such a good engine. Because all the wear is spread over the entire sleeve assemblies (two sleeves for each cylinder, one intake and one exhaust) Their wear rate is EXTREMELY slow. Whereas other early engines suffered from carbon buildup and accumulations, the sleeve-valve engine actually seals better and runs quieter once it has some miles on it. According to the people who have these cars, the engines don't wear out, they wear in, better and better, for thousands of miles beyond what a normal engine would have as a lifetime. After I saw some of the vehicles, heard them run, and talked to the owners of the cars, I finally had a grasp of how good sleeve-valve engines are.
People were just unfamiliar with them, didn't understand how they could possibly work or be reliable, and so they only sold in small numbers. Also, unlike a Model T, the average owner could not tinker with their Willys-Knight engine. Timing of the sleeves was fairly critical.
As engine enthusiasts, if you ever are at a car show, and there is a Willys-Knight Sleeve Valve engine car there, be sure to talk to the owners. They are always very proud of their engines, and will talk your ear off about how good they are. (I had Industrial Heavy Duty Ears installed years ago when I knew my wife, so I have no problem handling Willys-Knight aficionados.) They may even have one of the cutaway engines that you can crank, as the factory produced several thousand of these demonstrators for dealers, and they are greatly sought after by Willys-Knight car owners. It is not a complete engine, but a section that can stand on a counter and show how sleeve-valves work, so they could be explained to customers.

Well, I lookt up this sleeve valve stuff and now only have a rudimentary understanding of how it works. I would like to know more but it seems to be rather obscure. I did, however, manage to download a copy of H. Ricardo's 1950s book. Will look into it more. Thanx for pointing this out.


For others, I might point out that an egine canbe made from a Roots Blower when reversed. I have been trying to make on e for years. A "rotary piston", actually two, can be made with any number of lobes, the usual being two lobes. I prefer steam over ICE but either is possible. There are only 13 parts, extremely easy to assemble and disassemble. Two bearings, two identical gears, two rotary pistons, one crank, the body housing, two end caps. Well, that's 10 so I must have misst some parts.

 

[William May]

Well, I lookt up this sleeve valve stuff and now only have a rudimentary understanding of how it works. I would like to know more but it seems to be rather obscure. I did, however, manage to download a copy of H. Ricardo's 1950s book. Will look into it more. Thanx for pointing this out.


For others, I might point out that an egine canbe made from a Roots Blower when reversed. I have been trying to make on e for years. A "rotary piston", actually two, can be made with any number of lobes, the usual being two lobes. I prefer steam over ICE but either is possible. There are only 13 parts, extremely easy to assemble and disassemble. Two bearings, two identical gears, two rotary pistons, one crank, the body housing, two end caps. Well, that's 10 so I must have misst some parts.

Well, the only thing with sleeve-valve engines is they do smoke more than a regular IC engine, and they do it throughout their life. If you have a Model A Ford, and the engine smokes, you are getting close to needing an overhaul.
If you have a Willys-Knight, it just means you have a Willys-Knight, and you can expect to overhaul it sometime in the next 20 or 30 years or so, because it's been doing that since it was a new car.

Kind of like at Steam Car Meets, where the normal greeting for the steam car guys is "Hey, your cars on fire!", to which the proper response is "Yeah, thanks!"

 

[Joe]

Rotary engines still have problems that Mazda seems to have felt to be uneconomic to fix:

1) generally less durable than modern piston engines.

2) Unhelpful combustion chamber shape. High surface to volume ratio, and the petrol versions seem to suffer from delayed burn.
Possibly a diesel version would work better. Is maximum CR a limitation for this?
The LP X-engine at least addresses the combustion chamber shape problem.

3) Burning standard engine oil with all its additives, at the rate it does can't be good for sparkplug life.
- a portion of the sump oil is sprayed into the combustion chamber to lubricate the tip seals.
A separate oiling system with two-stroke oil would be sensible, if not a "good look" for the buyers.

Mind you , all engines used to drink a fair bit of oil at one stage.
Oil economy is a bit of a new thing, since the 1960's?

4) difficulty of development for emissions control.

It could possibly be done, but it would be a huge research effort.

Over the many years of production, they didn't seem to make a lot of progress on economy and emissions.

Getting reasonable fuel economy and lower nitrogen oxides at the same time would be tricky.

Owen,
In my experience I would respectfully disagree with your comments. I have owned four Mazdas, two of which were rotaries. Both would have been twelve or so years old when I got them. They were ridden very hard and put away wet, so to speak and other than a new exhaust on the first one I had 400,000 trouble free kilometers from the two. It was very easy to humiliate 5.0 litre Mustang owners. Fuel costs weren't great but they were better than V8s performing in the same manner. My other two Mazdas were a 3 year and a five year old V6 powered model. By this point I had grown up a bit, drove like I should and exceeded the maintenance recommendations. In the three years I had them I had no end of trouble with them. Spark plug change out required the intake manifold to come off. Three hundred dollars to change the rear three at the dealership. Computers and pollution control issues were continuous and one engine self destructed in 18 months. After 3 years I sold them for their catalytic converter value.
Changing the plugs on the rotaries was a 10 minute job, but as I had the correct plugs, I never had to change them.
Teams racing rotaries compete against big V8 which will be rebuilt every race whereas the rotaries will go a season. There is a chain of rotary powered pumps that run on sour gas. They are configured to have there oil changed whilst running and they will run 24-7 for 20000 hours at continuous high power settings. So in my experience and that of several people I know with similar experiences I would have to say point 1 is not my experience.

Point two, wether or not the combustion chamber shape is optimized or not, as it is in the Mazda end product it is a very effective design. A reciprocating model is certainly not optimal either yet it has proven to be effective. Beta was better than VHS but who won there ? Two features of the rotary design I would concede is that the shape is complex making it harder and more expensive to design and develop. And although a lot of effort has been put into developing a heavy fuel version I don't think anyone has managed to develop a practical version yet.

Point 3. Injecting sump oil is not ideal. There are aftermarket kits that use a separate oil reservoirs and inject two stroke oil. Some owners and most if not all aircraft applications simply mix the 2 stroke oil directly into the fuel. Anyone I knew of that ran the correct heat range of NGK spark plug, as did I, never had any issues. People who did run other plugs could find issues. Mazda went with sump oil because they didn't want be perceived as two-strokes and they didn't want to introduce another check or add item.

Item 4. They were California legal so they could obviously meet the same standards as everyone else selling cars did. Mazda listed there later engines as a 1.3 liter engine where as they were effectively the same as a four stroke V6 and 2.6 liter. This of course led to the idea that they were small fuel pigs. In fact if they were driven to perform like a 350 or 400 ci engine you got comparable efficiency, wide open the volumetric efficiency of a rotary is far better than a V, with its more convoluted flow and its valves in the way.

By the time Mazda got stuff figured out all the other manufacturers had established lines that they had sold to consumers as the best. To then retool and and convince your loyal customers you now have something better just makes no sense. This and the future of fossil fuels is why there is no hope for the for the engine idea that started this thread even if they could actually build one and prove their claims.