JtspellS SuperDork
April 4, 2016 12:41 p.m.

So patent's are being taken out for new rotary designs, good read and makes me tingly inside!

Article link

Knurled MegaDork
April 4, 2016 12:49 p.m.

I'd argue that rotaries are really large for their size, not compact, but interesting news nonetheless. I wonder if this means the ports will be on the left side of the engine now instead of the right.

GameboyRMH MegaDork
April 4, 2016 1:16 p.m.

Rotaries are large for their displacement but small for their power.

The real nasty engine packaging lie is the boxer engine. They're hardly shorter in length or height than a similar inline engine, and they're very wide. The only advantage is the lower CoG because the top 1/3rd of the engine's height is just the intake, the heads sit at crank level, and the exhaust is at oil pan level.

NickD HalfDork
April 4, 2016 1:21 p.m.

In reply to GameboyRMH:

"Hardly shorter in length or height"? I have yet to see a 1.8L I-4 that is as short in length or height as the 1.8L Subaru EA82 I have. I will give you the very wide part though

JtspellS SuperDork
April 4, 2016 1:21 p.m.

In reply to Knurled:

I think that it would still be on the right from the looks of the diagrams, I'm wondering if sound would change because of the counterclockwise motion.

wvumtnbkr SuperDork
April 4, 2016 1:35 p.m.

The pictures in the patent show that the engine is just essentially upside down. The exhaust comes out the top drivers side. The intake goes in to the ports through the bottom drivers side.

Check out figure 4 in the patent.

Figure 2 shows the drivers side of the engine with a 4 port intake manifold.

Again, they basically turned the engine upside down and called it something new and different. I don't see it.

Why doesn't direct injection with the renesis style ports solve the emissions and MPG issues?

wvumtnbkr SuperDork
April 4, 2016 1:35 p.m.

In reply to JtspellS:

It still runs clockwise.

wvumtnbkr SuperDork
April 4, 2016 1:42 p.m.

yep, I read the patent...

This is not new. It is simply upside down for better packaging. That is even what the patent is titled to portray. "Rotary Piston Engine Mounted on Vehicle".

The better performance comes in because the intake runner length has the POTENTIAL to be longer given it needs to run down the length of the engine....

Nothing to see here. Move along....

Damn it... I hate it when they get my hopes up with Rotary piston Engine discussions.

alfadriver MegaDork
April 4, 2016 1:51 p.m.
wvumtnbkr wrote: Why doesn't direct injection with the renesis style ports solve the emissions and MPG issues?

Some of the benefits of DI would mean an injector next to the intake port AND an injector near the spark plug. So no net benefit.

The benefit of charge cooling can probably be gotten with cleverly located intake injectors- since there's not a poppet valve in a rotary engine anyway.

wvumtnbkr SuperDork
April 4, 2016 1:55 p.m.

In reply to alfadriver:

Wouldn't the benefit of the direct injection (in a rotary) be no "relatively" cool walls for the fuel stick to on its way past?

In other words, I thought the large amount of surface area is what causes all the rotaries issues. The fuel will turn back into a liquid on the large surface areas and then just basically be swept out of the chamber into the exhaust.

Wouldn't DI solve that issue?

alfadriver MegaDork
April 4, 2016 2:18 p.m.

In reply to wvumtnbkr:

Not really- I would think it would get worse. Instead of vapor condensing on the walls, you would get small drops of fuel just sticking to the walls. That's already a problem in DI systems.

The DI "advantage" is mostly charge cooling which allows higher compression. The second advantage is a very nice stratified charge from injecting late. In a piston engine, you can do that from the same location. But rotaries would put one injector near the port, and one near the plug (remember, near the plug and near the port are the same spot on a piston engine)

wvumtnbkr SuperDork
April 4, 2016 2:27 p.m.

ohhh. I didn't realize that was already an issue with DI.

Thanks for the info!

Appleseed MegaDork
April 4, 2016 3:30 p.m.

I say rotarys area dead end design that lost favor after WWI because of advances in...wait we're talking about this, right?

djsilver
djsilver Reader
April 4, 2016 3:42 p.m.

On DI engines there's no fuel contacting the intake port or the back of the intake valve, so the ports and intake valves tend to get caked up with EGR gunk. What I've heard (but not confirmed) is that dealers service them by using those cleaning systems that drip some type of strong solvent into the intake manifold while it's running, to dissolve the EGR gunk and let it run through/burn in the combustion chamber. Otherwise cleaning would require dis-assembly.

Trans_Maro PowerDork
April 4, 2016 3:52 p.m.

In reply to Appleseed:

That IS a rotary piston engine.

I believe the oddballs here are speaking about the evolutionary dead-end that is the Wankel engine.

JtspellS SuperDork
April 4, 2016 4:10 p.m.

In reply to wvumtnbkr:

Some reason I was looking at figure 4 as though it was from the firewall, but even so still would be clockwise, having a derp week so far.

Kreb UltraDork
April 4, 2016 4:19 p.m.
Trans_Maro wrote: I believe the oddballs here are speaking about the evolutionary dead-end that is the Wankel engine.

Just you wait, one of these days Mazda will work out the kinks, and guys with Corvettes will be jamming this board asking for advice of how to rid themselves of those sluggish LSXs!

Oops. gotta run. The men in the white coats are coming again.

alfadriver MegaDork
April 4, 2016 4:24 p.m.
djsilver wrote: On DI engines there's no fuel contacting the intake port or the back of the intake valve, so the ports and intake valves tend to get caked up with EGR gunk. What I've heard (but not confirmed) is that dealers service them by using those cleaning systems that drip some type of strong solvent into the intake manifold while it's running, to dissolve the EGR gunk and let it run through/burn in the combustion chamber. Otherwise cleaning would require dis-assembly.

Not all of them do it, and even they don't do it equally.

But a better solution is crushed nut casing.

Dusterbd13 PowerDork
April 4, 2016 5:09 p.m.
alfadriver wrote: But a better solution is crushed nut casing.

Sounds painful.

alfadriver MegaDork
April 4, 2016 5:36 p.m.
Dusterbd13 wrote:
alfadriver wrote: But a better solution is crushed nut casing.

Sounds painful.

Difficult to find donors, too.

Trackmouse Dork
April 4, 2016 5:41 p.m.

With the intake on the bottom I can see the variable intake manifold from lemans coming. Could even be used for emissions.

Knurled MegaDork
April 4, 2016 6:41 p.m.

In reply to Trackmouse:

Automakers already do infinitely variable intake length. I forget who did it, but someone had an intake with runners that tangentially entered a round plenum, and an inner sleeve that altered the effective length of those runners by simply rotating. Brilliantly simple. Probably also got gummed up rapidly which is why it's a footnote rather than current standard practice.

Now that I realized the article had pictures, and I looked at them, the main thing I'm seeing is the exhaust ports can exit at a significantly "downward" angle, something you can't really do on a normally oriented engine. With any kind of fuel injection the placement of the intake manifolds is moot, too. The automakers are finally taking advantage of injection with "hot V" engines where the turbos are in the middle and the intake plenums on the sides. Get the long runners you want for the intakes with no hood clearance issues, get the turbos close to the exhaust ports with no framerail clearance issues. Win-win.

My brain hurts when I try to figure out how direct injection could be useful to a rotary. I thought the majority of the benefit of DI was that you could inject the fuel close to the spark plug, and with a properly shaped piston (bottom of combustion chamber) you could realize really great efficiencies, Diesel-style. How are you going to do that with a rotary where the "chamber" is constantly swiping past the spark plug and there is only a maybe 40 degree window for spark timing because of this, let alone aiming fuel into a bowl to hold up to the spark plug.

Mind you, I say this as someone who keeps getting crazy time-waster project ideas like using an early TDI's injection pump for direct injection on a rotary. Put enough 2-cycle oil in the gasoline and it should be lubricious enough for an injection pump to work, right? I'd really only want to inject it into the chamber roughly were the current oil metering pump holes are, so I can be sure no fuel goes out the exhaust port.

But, y'know, I can also do that by running timed/phased injection pulses with the injectors in the OE spots. The way Mazda did it. Since 1986. (GSL-SE/Super Injection/12A Turbo were batch fire)

codrus Dork
April 4, 2016 8:31 p.m.
Knurled wrote: With any kind of fuel injection the placement of the intake manifolds is moot, too. The automakers are finally taking advantage of injection with "hot V" engines where the turbos are in the middle and the intake plenums on the sides. Get the long runners you want for the intakes with no hood clearance issues, get the turbos close to the exhaust ports with no framerail clearance issues. Win-win.

Win-win except that the "hot vee" is very hot indeed.

My brain hurts when I try to figure out how direct injection could be useful to a rotary.

Put the injectors in the rotors! :-)

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