mazda needs to stop with this tease and get on the ball with this car.the more it waits,the more potential buyers it lose to the competion(i.e. frs/brz 370/g37 camaros n ponies)

 

anyone planning/wanting one of these next gen miatas?

 

if you flip through this a little, R&D spending goes up this year http://www.mazda.com/investors/libra...azdaAr13_e.pdf

 

That document looks like it was released one year ago. Actual FY2014 results are out, and they do indeed report an increase in the R&D budget from 89.9 to 99.4 billion yens. With a projection of 100 billions for FY2015.

The bad (and good) part is that, in the document you linked, the term "rotary" appears only once, in the "principal products" section, page 56. It seems like, after all, Mazda still considers the rotary as one of its core products.

Andrea.

 

Just looking back on the last few years of sae papers seems to me like mazda is releasing a few reports every 6 month or so. I just seen one from 2012 on liquid fuel vaporization. Obviously they are still developing and improving on the wankel. Although dosent sound like it will be what we know the rotary as now.

 

The number of papers published on rotary engines (in English at least) has slowed to a trickle in the past 15 years, compared to the early days when a bunch of companies were working on it. However back in April Mazda released a couple papers on oil consumption. Basically they partnered with researchers at MIT to figure out how oil moves around inside a 2009-spec Renesis engine using lab experiments and simulation.

The main conclusions for oil consumption were:

1) Even though rotary engines inject oil to lubricate seals, lots of oil is actually leaking past gaps in these seals and being wasted. It's sort of like oil going past the rings in a piston engine.





2) Part of the problem is distortion in the side housings that cause the oil control rings to make uneven contact as the rotor moves. In a piston engine it would be sort of like gaps forming between the lower piston ring (the oil control ring on a piston engine) and the bore wall.



So it sounds like there's hope Mazda can reduce oil consumption without harming the life of the engine. If they can design it so less oil leaks past seals, less oil will need to be injected.

 

more confusing news



" It is believed Mazda's engineers will manage to fix the Wankel engine's well-known problems related to high oil and fuel consumption and they will also increase torque without having to resort to a turbocharger. Expect an array of SkyActiv technologies and a power output somewhere in the region of 300 bhp (224 kW) sent to the rear wheels.

As a method to shave off weight, the model could adopt a two-door configuration like the RX-7 rather than RX-8's special four-door body style. It will ride on an extended platform of the new MX-5 and will be offered with a 6-speed manual gearbox and an optional 5-speed automatic. "

Mazda RX-8 successor with rotary engine planned for 2017 - report

Mazda RX-8 set to return in 2017 | Auto Express

 

The oil consumption improvement is from fixing the oil leakage as I described. The emissions and fuel economy improvement comes from adopting direct injection, redesigning the dimensions of the combustion chamber, reducing gas leakage across the seals, and adopting things like throttled water pumps and variable displacement oil pumps. Couple that with dual clutch tranny instead of a slush box for those who want only 2 pedals.

Much of that technology is in use in piston engines already, it just needs to be adapted to a rotary. And if the vehicle doesn't get lighter the real world economy will probably not improve enough.

 

I don't think that was posted here, but there has been another small hint at the possibility of a new Rx-7 from Mazda's next chairman Seita Kanai, as reported by motoring.com.au

Why would they answer with what is, essentially, a "no comment" if they werent't working on anything rotary related? Wouldn't it be simpler to just say "no" in that case?

Andrea.

 

OK lately Mazda has been coming out with some gay *** commercials... But this one isn't too bad. It feels like they are preparing the market for the new rotary

Conviction. Creativity. Courage. — The Mazda Way …:

 

Wow, much question, very rotary, such vague.

 

Direct injection could be pretty cool. Hopefully the fuel system will have as much head room as the N54 powered bmw's. They can take quite big increase in power on the stock fuel system, often upgrading only the low pressure fuel pump.

 

One thing's for sure, a rotary won't have the typical DI problem of carbon buildup on the valves. I wonder if it will be a problem elsewhere like around the intake port. Probably not the same extent as the back of a valve that used to be washed by the injections.

 

The auxiliary ports in the renesis do not have fuel injectors, so they experience a situation similar to the intake ports of a DI engine.
In the Renesis, most carbon buildup problems (usually resulting in stuck SSV or APV) happen when engines are babied. Just use the upper rev range and carbon buildup should not be a problem.

In addition, a DI rotary would have another unique advantage when compared to a DI piston engine: the fuel injectors in a rotary would never be exposed directly to the burning flame inside the engine, unlike what happens in a piston engine. This assumes that injector placement is similar to the one seen in the 16x.
That should make injectors failure very unlikely.

Andrea.

 

This assumes that injector placement is similar to the one seen in the 16x.

Mazda has called this arrangement "semi direct injection", ie injected directly into the engine, but not into the correct area of the engine.

The newest rotary shown for the generator seems to be "direct injection" where the injectors are immediately adjacent to the leading and trailing spark plugs allowing for a very localized pocket of ignitable mixture (allowing lean burn).

Similar to what is shown in the pic I posted from the '60s but to one side of the L/T plugs.

 

Well, I saw those tiny holes near each spark plug, but in the several videos depicting the RE generator they were never connected. It's likely that they are indeed fuel injectors though.

What puzzles me is that in one of the older Mazda papers about direct injection in a rotary (SAE 930677, if I'm not mistaken), that arrangement was compared to the semi-direct injector placement and found to be inferior. That was due to the early collision of the fuel stream with the nearby rotor face, which is not a problem with the semi-direct (called "upstream" in the paper) placement.
Perhaps I misunderstood the paper, or they solved the problem in the meantime.

Andrea.

 

What puzzles me is that in one of the older Mazda papers about direct injection in a rotary (SAE 930677, if I'm not mistaken), that arrangement was compared to the semi-direct injector placement and found to be inferior. That was due to the early collision of the fuel stream with the nearby rotor face, which is not a problem with the semi-direct (called "upstream" in the paper) placement.
Perhaps I misunderstood the paper, or they solved the problem in the meantime.


I would believe "direct injection" could be found to be "inferior" to "semi direct injection" if the operational parameters and system components were in some way limited.

Operation parameters-
Previous lean burn engines didn't run that lean as earlier NOx reducing cats could only do so much. Stratified charge with "semi direct injection" probably produced acceptable lean burn AFRs with much less costs involved.

Perhaps the "semi DI" stratified charge produced less NOx as with "DI" there is a dense rich pocket to ignite into the larger final lean burn area, where stratified has a dense pocket and a gradation into the leaner final burn area.

Components-
We have seen direct injection become mainstream with improved components. If the fuel delivery window is short enough and is precisely ignited as it streams from the injector there perhaps isn't a problem with liquid/gas fuel stream colliding with the rotor face.

Note-
Mazda has stated their next phase of skyactive gasoline engines they are working on will be direct injection compression ignition (no spark plugs).

I can only guess that this is enabled by the new lean burn cat technology and injector metering (volume and time) that actually dictates the flame front propagation speed.

 

Mazda claims to have solved the carbon problem in intake valves for their skyactiv DI engines, at least compared to the MZR, by changing the location and direction of injection to make sure the intake valves reach an optimal self cleaning temperature.

Also, they could have both the semi direct top-of-the-engine injector and the direct near-sparkplug injector. This will allow to have an homogeneous lean mixture and richened pockets near the spark plug for better combustion

 

This is likely the case, as I said things have likely progressed from where they were when the paper I mentioned was written.

The direct injection compression ignition (HCCI) approach should give quite a big efficiency boost, but I don't see Mazda introducing such a technology in the rotary. Sure, having two unique Mazda technologies in a single product (the rotary and the HCCI tech) could be a good marketing tool, but there's just too much that can go wrong. Much better to introduce such a new technology in a proven piston engine.
By the way, most likely the first HCCI engines will retain spark plugs and run in HCCI mode only at light loads, switching back to spark ignition at high loads. That way you only need to ensure proper HCCI operation in a narrower operating range.

This is another possibility. But would it make sense to move the main injectors from the intake ports to the engine core? Wouldn't a port injection system work just as well in that role? Who knows (well, Mazda knows )

Andrea.

 

Well, the further away from the combustion chamber the injectors are the more undesirable wall-wetting occurs. Having them near the primary locations or further in the intake side of the combustion chamber reduces this while increasing chamber cooling by the fuel. Now there could be increased rotor face wetting and carbon deposits to deal with though.

 

The direct injection compression ignition (HCCI) approach should give quite a big efficiency boost, but I don't see Mazda introducing such a technology in the rotary.

I don't know that it is possible to raise the rotary compression ratio high enough as the in a rotary the air charge has to have some space in the rotor to pass across the minor axis in the rotor housing.

Maybe in a DKM as it has no K factor (stroke).

I pointed out this technology Mazda is working on to show how much more precise direct injection fuel delivery has become since the older SAE paper you mentioned.

Wouldn't a port injection system work just as well in that role? Who knows (well, Mazda knows )

Well, we know because Mazda found out back in the '80s. The Mazda stratified charge engine placed the injectors on top of the rotor housings to inject into the stratified mass of counter rotating air charge.

 

Looks like I'll be eating bread every day for a long time! Cause I'll have to have it!!

 

7 things the Mazda Skyactiv Chassis tells us about the next Miata - CNET

so now that we have had a few weeks to stare at the Mx5 chassis, we can come to a few conclusions.

1. the front suspension looks like the Rx8/NC miata.
2. the transmission looks sorta like the old M type, but it looks heavily revised. i would assume it has grown another gear
3. the ppf/diff setup looks like we expect, the mounting points are beefier. hard to say, but in some pics the ppf looks more C shaped than it has
4. the rear suspension is new.

 

New Mazda2 to plug in - motoring.com.au

This comes from an interview with Mazda Australia Managing Director Martin Benders. If true, that would be the restart of rotary engine production by Mazda.

Andrea.

 

New RX-7 to get 335kW turbo rotary

Uhhh, so now they're toying around with the idea of a 450hp twin-scroll turbo Porsche-killer…

Thoughts? Obviously to be taken with a grain of salt without any official notice.

Cheers,
-Matt