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Mazda patents show rotary engine for range-extended EV

Two years ago, Mazda introduced a fascinating range-extended electric car called the Mazda2 RE Range-Extender. It took an electric Mazda2, and dropped in an itty-bitty 330cc rotary engine. It wasn't the rotary-powered sports car we had hoped for, but it seemed like a unique way to keep the quirky engine alive and kicking. But not long after the car's reveal, it seemed to disappear. Now the basic idea has resurfaced with a few modern updates in a couple of US patents. The first patent is pretty straightforward and describes a range-extended EV similar to the BMW i3. At the front is an electric motor driving the front wheels. At the back is an internal combustion engine that powers an electric generator. In the middle is a lithium-ion battery for storing and delivering electricity. It's the same set-up as that Mazda2. The second patent is for an engine start-and-stop system, but specifically for rotary engines. The system is designed to shut off a rotary engine when not needed, much as modern piston engines do. It also stops the rotor in a position that closes the intake port to ensure no fuel or exhaust emissions slip out through the intake tract. This is necessary since there are no valves in a rotary, and air and exhaust come through ports that are "opened" and "closed" by the rotor itself. The patent also describes the possibility of firing a spark plug after the fuel has been cut to eliminate any leftover fuel emissions. This system would theoretically improve a rotary engine's fuel economy and emissions significantly, which would be a boon as those are two of the rotary's major weaknesses. The rotary-engine patent also includes the same range-extended powertrain drawing as the first patent. It's there as a description of a possible application. And in such an application, where the rotary wouldn't have to run all the time, the system could take advantage of the rotary's inherent strengths. Weight can be kept low thanks to the engine's small dimensions, which should help in keeping the car sprightly and efficient. Rotaries are renowned for smoothness, too, so it shouldn't need too much refining and sound deadening, the latter of which adds more weight. The small size would also help with packaging, leaving more space for people, cargo, or possibly batteries. And since it has been patented, the company may be looking to bring the system to market.

Lexus tops Consumer Reports reliability rankings, unseating Mazda

Lexus is back on top of Consumer Reports' annual reliability rankings. Toyota Motor Corp's luxury division dethrones last year's winner, upstart Mazda, to second place, while the Toyota brand itself rounds out the podium in third place. In general, while Asian brands topped the list, Europeans ranked second, and domestics brought up the rear.  Lexus' high marks stem from the Land Cruiser Prado-based GX SUV, which got a perfect score of 100. Mazda's second place finish was the result of strong showings by the Miata, CX-9, CX-5, and CX-30, but dragged down by the Mazda 3's mid-pack score. Likewise, nearly all of Toyota's lineup, from Prius to Avalon, all had very high marks, but the RAV4 and Corolla Hatchback brought down the class average. Like last year, the only American brand to break into the top ten was Buick, which ranked 5th thanks to good scores for the Envision and Encore (though the Enclave ranked sub-par). Eight of the top 10 brands were Japanese, with Infiniti in 4th, and Honda, Subaru, Acura and Nissan following Buick in that order. Mini, in 10th place, was the only European brand in the top 10. The bottom spots went to Jeep, Tesla, and once again Lincoln in dead last. While all Lincolns received poor scores, the Aviator was notable for getting only 3 points out of 100. Similarly, last year's lowest-scoring vehicle was the Ford Explorer, with which the Aviator shares a platform. It wasn't all gloom from the domestics, however. The Chevrolet Trailblazer tied the Lexus GX with a perfect score, but overall Chevy brand ranked 14th, pulled down by the Corvette, Silverado 1500 and Tahoe. The Tahoe tied with the GMC Yukon with the lowest scores this year, just 2 points each. Both the Silverado 2500HD and the nearly identical GMC Sierra 2500HD were among to top scoring American vehicles, along with the Ford Bronco Sport, Mustang Mach E, Ranger and Chrysler 300. Consumer Reports also points out that the oft-said line that electric vehicles are less prone to problems due to fewer moving parts isn't necessarily true. The Audi E-Tron and Tesla Model X each got a score of 5, the lowest of their respective brands, due to more and more technology being crammed into these higher-priced EVs. For a complete list of rankings by company and of individual models, check out the full study at Consumer Reports. Related Video: This content is hosted by a third party. To view it, please update your privacy preferences. Manage Settings.

Mazda Skyactiv-X Review | The revolution begins with a squeeze-bang

The matte black Skyactiv-X prototype looks like a rough Mazda3, perhaps reconstructed after a bad wreck by an over-enthusiastic owner of a spot welder and lots of gaffers' tape. Ribbed ducts poke out of the dash sending two breaths of conditioned air to no one in particular. Even its revolutionary engine, the thing we're here to experience, is entombed in a massive, nondescript cover to mask its unseemly noises. It's a wild, strange way to meet a very unconventional vehicle that promises diesel-like fuel economy, a wide torque band, and an exotic method for burning less gas than ever before. It takes a few hours for Mazda's engineers to explain the fundamental principles of operation. For more detail, read our Skyactiv-X Spark Controlled Compression Ignition explainer, but here's a very brief overview. Skyactiv-X marries some traditional gasoline engine characteristics with a novel form of compression ignition called SPCCI. The key for Skyactiv-X is to use very high compression in the cylinder and an extremely lean fuel-air mixture. Squeezed right to the cusp of getting hot enough to blow up all on its own (which is very hard to predict), a squirt of extra gas and a spark interject to cross that compression-ignition threshold in a controlled and predictable manner. See the animation below: That takes a few essential components to get just right. One is a massive amount of computer processing power and some pressure sensors in the individual cylinders, because the ambient conditions change how and when these things happen. Skyactiv-X uses a clutched supercharger to pump in additional air when needed to nail the mixture precisely, and high-pressure injectors to get the low ratios of fuel to disperse properly in the chamber. And since it operates like a conventional gasoline engine sometimes, it uses valve timing to lower the very high compression ratio so it doesn't reach combustion ignition in that mode. In practice, the Skyactiv-X runs in compression ignition mode most of the time. In practical terms, that means it drives like a torquey gasoline Skyactiv engine. The torque curve is broad and flat — diesel-like in that respect. That also means it can get away with using a six-speed transmission and a lower final drive for better response. There's enough grunt and economy together that Mazda can let the engine spin faster — at 60 mph, it's running at roughly 1,000 more RPM than a similar gas engine, with greater efficiency.