• May 31st 2007 at 11:02AM
  • 16
In order to qualify its new Mazda2/Demio for Japan's Green Tax exemptions, Mazda has developed a trick new 1.3L Miller-cycle powerplant that's naturally-aspirated, of all things. Normally a supercharger is required in a Miller-cycle engine, which makes Mazda's new mill particularly intriguing. It will be combined with Mazda's first CVT, and thanks to a 222 lb. diet, the new Demio is expected to return 54 mpg. In the press release after the jump, Mazda makes a big deal about how efficient its new Miller engine is, but fails to mention how much power it makes. That's not surprising, since it's generally accepted that, compared to our traditional Otto-cycle engines, a Miller trades off power for increased efficiency (that's what the supercharger's usually for). With this new engine, however, Mazda further cements its reputation as an automaker with a penchant for alternative forms of internal combustion.

[Source: 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.

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    • 1 Second Ago
      • 8 Years Ago
      With about half the HP of fit/Jazz how could it possibly manage comparably performance? It certainly won't weigh half as much.

      The standard 1.3l is about 65 HP, the Atkinson cycle probably knocks that down to 50 HP. Ok for a hybrid engine, but pitiful standalone.

      Performance will be comparable to the Smart and nowhere near Fit/Yaris. At least in North American trim where they have over 100HP.
      • 8 Years Ago
      This car looks pretty cool as it is, and that color is awesome. This could be a great car if it had triple-digit horsepower.
      • 8 Years Ago

      screw ford.
      • 8 Years Ago
      Hopefully its flex fuel. E-100 would be nice.
      • 8 Years Ago
      I'd agree with calling this an Atkinson cycle engine.

      Rick, what's with the "screw Ford?" This car is the basis for the Ford of Europe B-car which is also coming to America. What, did you forget that Ford owns a majority stake in Mazda?
        • 8 Years Ago
        Because Ford will not keep this body, it will look like a baby Focus. I dislike Ford's body panels, lights, an overall styling. The interior is OK, but then you also realize that Mazda provides owners with a rental and Ford does not, while the car is being serviced. Ford might own a portion of Mazda, but that in no way reflects on Ford's design or costumer relations. I don't want the Ford Fiesta or whatever, I want the car exactly above, the Mazda2.
      • 8 Years Ago
      "It will be combined with Mazda's first CVT"


      • 8 Years Ago
      the performance will be nowhere near Fit levels. Not with a atkinson 1.3. this thing is going to be like 60 hp at most
      • 8 Years Ago
      "However, in practice, the actual compression ratio is determined by the valve timing"

      I dont know about anyone else but I read "variable compression ratio".
      • 8 Years Ago
      Toyota gets 76 HP out of the 1.5L in the Prius. I think that is in line with expectations. That would yield 65 hp.

      Which is probably high, given that the standard 1.3 this is based off is 65hp and this one will sacrifice HP for economy.

      My guess is 50-55 HP.

      • 8 Years Ago
      Bring it to North America sure, but they can keep the 55 HP engine and give me the 1.5l it was shown with before.

      40mpg and 100hp is fine by me. 55HP will present more danger than I would want to face while merging.
      • 8 Years Ago
      I expect Mazda to do for this engine as they did with the Wankel engine. It will be an achiever.
      • 8 Years Ago
      Um, correct me if I'm wrong here, but the Miller cycle engine uses forced induction (not necessarily a supercharger) to help with the compression. The intake valve remains open during part of the compression stroke, and therefore the compressor (be it turbo or super) accomplishes the first part of the intake charge compression. If you do not use a forced induction system, this is called an Atkinson cycle, like the Prius uses. So isn't this car really just using an Atkinson cycle?
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