Wankel Rotary w/base/Atkinson/Miller cycle modes.

Toyota introduced the technology right at the time of the global auto recession. It does add complexity and cost, but can benefit most engines, but the higher compression the more it can help, it has the smallest benefit on an atkinson engine like the one in our prius.

Here is fiats interpretation

Fiat's Multiair Valve-Lift System Explained - Tech Dept. - Car Reviews - Car and Driver

The systems can do early closing for higher low rpm torque, and valve opening in losing to give better motion in the intake charge.

This looks like less expensive and better control technology than the toyota system, but I don't know. BMW is on their second system. I expect toyota to refine their system and use it on more cars. Mazda has a similar system as part of skyactive.

AFAIK the problem with lean burn gasoline is it does not do well with the current catalytic converters. This is one advantage that diesel engines still have the ability to do lean burn. Toyota's answer is agressive egr so that low levels of power can still be produced while working with todays cat technology.

 

The I4 has the same set up as the N55 but with 2 less cylinders.
BMW 3-series Review: 2011 BMW 335i Sedan Test – Car and Driver

For 2011, BMW dropped the N54 twin-turbocharged 3.0-liter inline-six and replaced it with the N55 single-turbo 3.0-liter. With direct fuel injection, a twin-scroll turbocharger, and BMW’s Valvetronic variable-valve-lift system—the N54 covered its turbo and direct-injection bases but lacked Valvetronic—the new engine bests its predecessor’s EPA-estimated fuel economy, 19 mpg city and 28 highway versus 17 and 26, respectively. Power remains the same: 300 hp and 300 lb-ft of torque. Peak horsepower still arrives at 5800 rpm, but the new motor delivers its torque punch at 1200 rpm, 200 revs earlier.[/QUOTE]
Note valvetronic is what controls valve timing and the single twin scroll turbo reduces turbo lag and allows the boost to come on early. In the I4 its at 1250rpm, or on all the time except idle and extremely low power levels, but air is restricted by the valves instead of a throttle plate. The valve timing/lower rpm boost leads to 2mpg gain. The normally aspirated engine gets 18 city - 28 hwy. BMW is replacing it with the turbo 4 for fuel economy.
2012 BMW 328i / 3-series Sedan First Drive – Review – Car and Driver

The higher estimates are with the automatic. This is 6mpg better than the outgoing 6 cyclinder of the same power. We can't compare to an atkinson right now, since none is in stand alone operation. I hope bmw adds the activehybrid system to this, and then we can compare it to the lexus gsh, which has similar hp in an atkinson configuration.

 

I'm not doubting you,but my googlefu wasn't up to finding why that would be. Most sources discussing products from crude don't go into detail beyond gasoline. Gasoline's reported density does vary. If regular is the less dense, there would be a higher volume for given mass. In which case, it would technically be more made, but we don't use mass, or even temperature adjusted volume, for retail purchases and fuel economy.

A seperate thought experiment is if we make just regular from crude, and use outside, hopefully renewable, octane boosters, such as alcohols, will we keep the fuel efficiency advantage of the premium fueled engine?

Which is why I've been saying a Turbo can be used in the same manner as a hybrid for improved fuel economy. It lets engine output be matched to the majority of driving for fuel efficiency. The turbo/hybrid just gives the boost for what would be a slow, possibly unsafe car, to acceptable performance to be able to sell.

The Chevy Cruze has a 1.4L turbo in most of its line up. It gets better economy than the base 1.8L. It even does slightly better than its replacee, the Cobalt with 2.2L, which I think might be lighter.

Being able to from Otto to Atkinson would be a improvement in any engine. I don't see it being accepted here in a standard fuel injected engine because of octanism. Has Toyota combined it with DI, and put that into a production model?

There is work going on with Atkinson rotaries. Most manufacturers are just invested in the piston. Even Mazda seems to be abandoning, or at least putting on hold, rotary development.

I think they have a future, either on board or as add-on, for electrical generation with plug ins do to packaging. Their smaller size and lighter weight negates some of the penalties of having an on board generator. Its comparable smoothness also helps. The weight and size savings also makes a trailer generator more managable. The Long Ranger trailer available during the time of EV1 used a 500cc motorcycle engine. The rotary in the Audi A1 E-tron is only 125cc. A rotary genset might even fit onto a hitch haul platform, so there won't be the downsides of a trailer.

If batteries and EV range advance as many hope, I think the rotary's comparable fuel inefficiency will be overlooked for its packaging advantages. With a rated EV range of 35 miles, the Volt's ICE is only used a third of the time. While it disappointed some, the Volt's gas fuel economy isn't abysmal. As long as the rotary genset's economy isn't worse, I think it can successful for the fewer and fewer times it would be needed.

An atkinsonized one may help if it doesn't negate the packaging. Just running at a constant load in a genset will help with efficiency. An Otto/Atkinson model isn't needed in such case. Perhaps for hybrid with parallel operation. In a straight ICE, I don't see it being successful. While a rotary produces lots of power, it makes less torque. Which is what people really want when they speak of power. Though, the transmission in this hypothetical car has its input.

Lucky bastard.

It's around a 50/50 mix I believe. Either way, my point was that Otto/Atkinson valve timing on a non-DI engine has a chance of success because most of the world's regular gas is premium to us.

This has a chart comparing the octane of some regional fuels and other fuels:
[ame=http://en.wikipedia.org/wiki/Octane_rating]Octane rating - Wikipedia, the free encyclopedia[/ame]
Germany's premium has a higher rating than ours.
Australia and New Zealand have octane ratings in the range the US uses, I wonder if they have octanism also. Actually, is it prevalent everywhere there's an option in fueling?

As long as you aren't driving your Porsche Africa, you should be fine on lead front. Even Nascar stopped using leaded fuel here.

 

I'm wondering at what point it will make sense to drop the mechanical linkages for valves and go to some sort of direct computer control?

Tom

 

Considering the amount of power and precision control required to operate ICE valves in small hot confines , probably not in out lifetime.

 

Siemens and BMW did build a prototype about 10 years ago of a camless engine, but it was more expensive and noisier than the system bmw eventually went with. Fiat's multiair hydrolic system comes close to the abilities for low costs, so it may be awhile before camless systems. There is one company pushing it though, and the idea of getting rid of all that hardware brings up lots of possibilities.

Valeo has customers for camless engine with "smart valve actuation"

Valeo also has made many components for a 42V autosystem, and I would expect that to be implemented before camless engines. I personally favor the ball valve design over the popet if these things get implemented.

Not to leave Mazda out, their new skyactiv has valves that does this trick too, and along with the bmw turbo 4 is one of ward's auto world's 10 best engines.
SKYACTIV-G (Petrol Engine) | Mazda Motor Europe

The exhaust manifold can't fit in the mazda 3, so mazda's US regular gas version will only go to 12:1. When they do a redesign to fit the bigger manifold they will sell one at 13:1 for the lower octane regular gas in the NA market. I'm sure someone will be able to tell us the effects of these different engines. That 12:1 version would be great to turbo charge and use premium gas for maximum performance, say in a redesigned mazdaspeed3 or rx-8. Someone will be able to test efficiency of regular/premium compression changes with 2 different engines

Mazda is working on a new rotary with different geometry, aluminum block, and DI to close the efficiency gap with piston engines. With their work on skyactiv I don't know whether they will build a car to put it in. Maybe a 0.5L version in a PHEV:rockon:

 

No, there is no DI engine available in the Cruze, or Volt, at this time. At least in the states. Europe always gets a wider range engine sizes and fuel types.

I posted a link to a summation on one prototype earlier in the thread. IIRC, it was diesel fueled, but two to three other designs were mentioned. It was early stage work, mostly computer modeling, and may not have advanced father.

Audi put a rotary half that size in a PHV. I misremembered it as 125cc here and likely elsewhere on the boards. I think I once was trying to picture its size in relation to my lawnmower.
Here's a quick summation of it.

http://en.wikipedia.org/wiki/Audi_A1#A1_e-tron
Dropping the rotary for piston might happen in the production model since VW doesn't want to put out the costs for a production rotary. I'm hoping for a Mazda partnership. It should be good for both with Mazda getting a better deal on hybrid tech over what they have now with Toyota.

 

You made me curious, so only google, no real knowledge - has a cut way picture of the alternator/wankel design
How Audi Hybrids Could Keep the Wankel Rotary Alive - Feature - Car and Driver

How Audi Hybrids Could Keep the Wankel Rotary Alive - Feature - Car and Driver

That includes the generator. 15KW also is underpowered for the car, which means the wankel-generator would probably grow, but not that much.

There are interesting facts on the link.

 

About a steady 60 mph for that class of car assuming no adverse wind, grades, or AC or other significant loads like major battery charging.

Small Wankels are also thirsty buggers

FTA

155 miles - 30 on battery = 125 miles.
125 Miles/3.2 gallons = 39 mpg which actually looks pretty good for a Wankel.

If you bumped it up to 35 hp it would start to be a practical cross country car except for long mountain grades and headwinds.

36 HP VW bugs weight about 60% as much, had a much smaller frontal area and a relly bad Cd. Probably took a similar amount of power to move down a leval road at a steady speed. Their 20 second 0-60 times, 70 mph top speeds and miserable highway grade performance wouldn't be acceptable today so it would need enough power to assure it almost never ran out of battery power. Still, it would be doable if you could put up with occasionally being reduced to 1957 VW performance levels and a relatively inefficient Wankel engine for long trips.

Still, it has place as a city car with occasional long trips.

 

This A1 is only intended for Europe, maybe Asia, where things tend to be more centered around a city, and the cities less spread out. I would love one, but people here will find it tedious stopping every 120 miles for fuel tedious on a trip. They really won't, but 155 compared to the 500 that is advertized for several vehicles will make them think it.

They also kept the interior space the same to the straight ICE model. Which may be part of the reason for the small fuel tank.

We here always jump too the Prius for a fuel efficiency comparison. We need to keep mind the Prius is the outlier in available vehicles' fuel efficiency. The current next best are nearly 20% worse than the Prius.

Considering that, and that burning gas should only be a sometime thing with it, 39mpg is pretty good.

 

That swivel wheel pod might be perfect for an EV range extender.