ASH8

WoW...This has come out of the Blue from Mazda...
The ALL New Mazda 2 released this July is to have a 1.3L Miller-Cycle Engine last seen in the Euno's (Millenia) in the late 1990's...


From Mazda....

Mazda Develops New Naturally-Aspirated MZR 1.3L Miller-cycle Engine

- The new MZR 1.3L engine powers the all-new Mazda Demio to achieve a fuel economy of 23.0 km/L and qualify for Japan's Green Tax exemptions -
HIROSHIMA, Japan—Mazda Motor Corporation has developed a new, naturally aspirated MZR 1.3L Miller-cycle engine, which will power the all-new Demio (known as the all-new Mazda2 in overseas markets) when it goes on sale in Japan in July 2007. In combination with Mazda’s first continuously variable transmission (CVT), the engine will assist the new Demio to achieve a 10-15 mode fuel economy of 23.0 km/L, an improvement of approximately 20 percent over the 19.2 km/L rating of the current model.



Newly developed from the current MZR 1.3L DOHC aluminum engine, the naturally-aspirated MZR 1.3L Miller-cycle engine employs delayed closing of the intake valves in order to reduce pumping losses and improve thermal efficiency through a higher expansion ratio. Intake valve timing is optimized by the Sequential Valve Timing System to provide improved fuel efficiency over the current MZR 1.3L engine when cruising and accelerating. In conjunction with the CVT, which transfers torque at low speeds without power loss and eliminates gear-shift shock, the setup achieves excellent fuel efficiency as well as a smooth and exhilarating ride.



In addition to this new, highly efficient powertrain, the all-new Demio has been made approximately 100 kg lighter than its predecessor through weight reduction techniques, which have resulted in nimble handling and significantly improved fuel economy.



The Demio model with the naturally aspirated MZR 1.3L Miller-cycle engine combined with the CVT transmission achieves a fuel economy that is rated as 20 percent or better than the level specified by Japan’s 2010 fuel economy standards. Exhaust emissions are also at least 75 percent lower than 2005 standards, which conforms to Japan’s Super Ultra-Low Emissions Vehicle (SU-LEV) standard and qualifies the Demio for Green Tax exemptions.



Through its Sustainable Zoom-Zoom plan that was announced in March 2007, Mazda declared its intention to pursue the harmony felt between driving pleasure and environmental and safety features, and its quest for an advanced Zoom-Zoom world. This includes the ongoing desire to create captivating design, to provide our customers with continual driving pleasure and to develop improved safety and environmental technologies

ASH8

I think we will now possibly see the Miller-Cycle hardware technology used in Mazda's other MZR Engines in the ALL New Mazda 6, the next gen Mazda 3 and the MX-5.

MP3Guy

Not a bad idea- the thing actually WORKS, and it places no hardships on anyone- car, mechanic, etc....

rotarygod

Someone double check my math but 23km/l works out to 54 mpg. Is that right?

dynamho

Sounds about right. Hahaha!
Way to go Mazda!

Mech_head

What is this Miller-Cycle stuff any way? I think i remember Mazda having it in another of their cars in the past but i can remember which one.

mtrevino

Interesting, so after looking it up on How Stuff Works-
http://auto.howstuffworks.com/question132.htm

Does that mean that there's a supercharger as well? And is the engine, essentially the same as the otto engine, but with just different valve timing? Basically, can anyone please explain in laymans terms?

michael

BOOSTD 7

54mpg! I'm speechless.

PoorCollegeKid

Just to clarify, the mileage given is the 10-15 mode mpg. For comparison's sake, the current Prius achieves 35.5 km/L (83.5 mpg) in this test and only 46 mpg on the new EPA test. So, if this car makes it to our shores, it'll probably be rated in the mid to high 30s, which is still decent, but not as impressive as an honest 54 mpg would have been.

As a side note, the rumored 96 mpg next-gen Prius is likely tested on this cycle. So, it'll achieve a 15% increase from its current fuel economy (up to ~53 mpg by the new EPA test) rather than the 100% increase in economy many people assume.

Gambit

I got 55mpg, but i might have my liters-to-gallons off a little

still....

Rootski

iTrader: (1)

Yes, but the manufacturing process of the Prius greatly offsets any environmental benefit, with this Mazda2 makes no pollution while being built than any other car.

Gambit

I says Euno's (Millennium) in the article

i think it meant the Millennia

rotarygod

Technically this isn't a Miller cycle engine. It is an Atkinson cycle engine. The only difference is that the Miller cycle uses some form of supercharging and the Atkinson cycle does not.

zoom44

yes the are making a point of saying "naturally aspirated" 1.3/ miller cycle . which is atkinson cycle. The Prius actually uses Atkinson cycle in its IC engine also.

PoorCollegeKid

It was in the Millenia S back in the 90s.

A Miller cycle engine is almost identical to an Otto cycle engine, except for its valve timing. The intake valve closes well into the compression stroke, so piston compresses the intake charge against the S/C induced boost. So, if the S/C is providing 6 psig of boost, then your in-cylinder pressure will be 6 psig until the intake valve closes. This means that your peak cylinder pressures and temperatures will be lower for a given compression ratio (since the actual compression ratio is much less than the quoted compression ratio), which means that you can run higher compression ratios and still avoid knock. The higher intake pressures also reduces pumping losses, which are related to the difference in exhaust and intake pressure. A high intake pressure means that air will more easily flow into the cylinder, which means that less work is needed to pull it in, while a high exhaust pressure means that exhaust gases will less easily flow out of the cylinder, meaning that more work is required to move then out. So, higher intake pressures and constant exhaust pressures means that less work is needed to pump gases into and out of the cylinder, a term that is referred to as "pumping losses". For a high enough boost pressure, then, these losses can even become pumping gains and increase the output of the cycle. However, a supercharger is driven off the crank of the engine, so some of the engine's power must go toward running this device. This somewhat offsets the lower pumping losses.

An increase in compression ratio might seem disingenuous, seeing as how the air is still only compressed approximately the same amount as in a normal, lower compression ratio Otto cycle engine due to the late intake valve closing. If you look at the compression ratio as the expansion ratio for the power stroke, however, then it starts making more sense. A higher expansion ratio allows the burned gases to be expanded more, which, in turn, increases the amount of energy that is extracted from these gases. So, you use more of your fuel's energy, your mileage goes up, and your EGT go down. This, along with the decreased pumping losses, result in an efficiency increase of a few percentage points over a conventional Otto cycle engine.

Summary: A Miller cycle engine is supercharged, so the intake pressure is always higher than ambient while the exhaust pressure is always fairly close to ambient (though a little higher). This means that pumping losses are reduced (since pumping losses depend on [Pe - Pi]), which helps increase engine efficiency. Unfortunately, the work done by the compressor isn't free and so saps some power from the engine. The key to this cycle is that the intake valve is closed very late and so the air and gasoline mixture can only be compressed to the supercharger's boost pressure for as long as the valve is open. Once the intake valve closes, it operates like any other piston engine. This results in the unburned gases being compressed less for a given compression ratio, thus allowing higher compression ratios to be used while keeping the final peak pressures and temperatures of the unburned gases the same. This is important because these values control the onset of knock. An increase in compression ratio increases the efficiency of an engine not because it compresses the intake charge more (since this clearly is not the case in a Miller cycle engine, where the air is still compressed about the same as a normal, lower compression ratio Otto cycle engine), but because it expands the burned gases more. Looking at this number as an expansion ratio makes everything a little more clear.

MazdaMonkey

Autoblog confirms the 54mpg.

http://www.autoblog.com/2007/05/31/m...-mazda2-demio/


But, CVT=LAME!!

My parents told me that had a Mazda2 as a rental car last week and loved it.

CarAndDriver

As others posted, Mazda used in the Millenia S here in the states and elsewhere.

A great car that did not sell nearly as well as it should as should have been continued so Mazda could have a nice sedan in the entry-level luxury class.

Gotta love Mazda engineers!

CarAndDriver

Article on the Miller Cycle Millenia engine: http://www.rx7uknet.dircon.co.uk/binhist/miller.html

I hear the CVT in the new Altima is pretty good.

ASH8

I agree with RG, if it has no supercharger (which it appears it has not) then it is not a true Miller-Cycle Engine.

I now have my doubts that this engine will make it outside of Japan in this car.

Australia has the new 2 here later this year with the NA 1.5l engine option,
with the MC Engine???.."Computer says NO"

CarAndDriver

Lucky Australia....20 million people and gets more interesting cars lately than the US.

ASH8

Yes, I can not understand either C&D why MNAO have not given (yet) the green light for a LHD version for the States, I think it would be a great little seller for the young college girl or guy very economical and ZIPPY!!!
Or for a second family car for the wife that's cheap.

There is a Mazda 121 (Mazda 2 was the replacement) here in Sydney who has done over 350,000KMS in her 1992 series Mazda. She loves it and still going strong, just oil and petrol, tyres, brakes and one timing belt!..

The Miller_cycle announcement by Mazda just goes to show how tight lipped MMC Japan are when it comes to any changes.
I am still hopefully we will see upgrades on the RX-8 at this years TMS.

Jedi54

iTrader: (7)

i'm confused as to why they're calling it a miller-cycle engine... I'm just not buying this whole "naturally aspirated miller-cylcle". Why not simply call it an Atkinson?

Is it because Mazda wants to claim that they're stillusing a miller-cycle engine? Or because they have the first "non- SC" Miller-cycle?

dynamho

Don't know if this is a repost, but since we're on the subject....
An Atkinson Cycle Rotary...
http://white-smoke.wetpaint.com/page...+Engine?t=anon
... now if you supercharge it....

Jedi54

iTrader: (7)

is it me or does it look like it's got a fish in there...

CarAndDriver

lol