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How Mazda got Skyactiv-X to work is incredible

"Take everything you know about engines and turn it around," Mazda North America Vehicle Development Engineer Dave Coleman says, patiently and with a look of benevolent pity, as he's quizzed about the particulars of the company's new engine. The Skyactiv-X engine is enigmatic — and deceptively simple in operation. And the bottom line for American consumers is that they'll be able to buy a car (or crossover; we don't know yet what vehicle will first get it) by late 2019 that provides diesel-like fuel economy but runs on regular old gasoline. In between diesel and spark ignition, but it's neither To truly understand it, you have to dive into the contradictions. Take that regular old gasoline: Contrary to common sense, the lower the octane, the better it works. In the lab, the Skyactiv-X engine loves 80 octane. The lowest Americans get is 87, so the engine is tuned for that octane. Go higher and you lose some low-end torque. Coleman was right. It's hard to wrap your head around an engine that thrives just at the point when most gas engines would aggressively self-destruct. It uses a supercharger to pump additional air — but not additional fuel. It uses spark plugs to start a combustion cycle that normally doesn't need a spark. And, quixotically, it's not displacing Mazda's own American-market diesel engine, currently languishing in a seemingly endless hell of regulatory approval. More bizarre: Mazda is a tiny automaker facing real existential headwinds, and gasoline compression ignition is a massive challenge. GM and Hyundai announced compression ignition, or HCCI, projects (full name, homogeneous charge compression ignition) to great fanfare, but they never amounted to a production hill of beans, crippled by reliability issues or horrible vibrations. Worse, they only worked at an unusably narrow range — low RPMs and low loads. HCCI research improved direct-injection gas and diesel engine technologies for these companies, but HCCI itself remains untamed. The benefits of lean combustion Why even try to tame HCCI? The answer is much better fuel economy and lower emissions. Less burned carbon-based fuel, less carbon dioxide released. That's simple. But there are some thermodynamic reasons for the lean combustion you can achieve with compression ignition that are worth explaining. The ideal amount of fuel for a conventional engine to burn is about a 14:1 air-to-fuel ratio. That lets every molecule burn nicely, in theory.

Jay Leno celebrates Mazda Miata's 25th birthday

Ask a car enthusiast what the best driver's car on the road is, and the Mazda MX-5 Miata is very likely to come up rather quickly. Unjustly saddled with a reputation as a "chick's car," the Miata has been, over its three generations, one of the finest driving instruments ever built - it's light, agile and rear-wheel drive with direct, snappy steering, an engine that revels in being revved and a precise, smooth-shifting transmission. The fact that it's ridiculously affordable and reliable is simply a bonus.
It should come as no surprise then, that a car with these traits has endured for 25 years, a milestone reached only by some of the most famous nameplates in the auto industry - Corvette, Mustang, F-150, SL, M3 and so on. To celebrate its 25th anniversary, Jay Leno spent some time with the little roadster that could, while also chatting with two of the Mazda employees that were central to the MX-5's arrival on the world's automotive scene, Bob Hall and Tom Matano.
Take a look below for the latest video from Jay Leno's Garage on the excellent Mazda MX-5 Miata.

10 of 18 midsize SUVs earn 'good' IIHS side impact safety rating

It's not terribly surprising that midsize SUVs earned better safety ratings than small SUVs in the latest side-impact tests performed by the Insurance Institute for Highway Safety (IIHS). Just how much better they scored, on the other hand, certainly raises an eyebrow. Ten out of 18 midsize SUVs earned the highest rating of 'good' in the stringent new test, altered for vehicles starting with the 2020 model year with a heavier barrier (4,200 pounds) that moves at a higher speed (37 miles per hour) and is fitted with a hard honeycomb frontal structure. By way of contrast, just one out of of 20 small SUVs earned a 'good' score.  SUVs that receiving 'good' scores were the Ford Explorer, Infiniti QX60, Lincoln Aviator, Mazda CX-9, Nissan Pathfinder, Subaru Ascent, Toyota Highlander, Volkswagen Atlas, Volkswagen Atlas Cross Sport and Volkswagen ID.4. For EV fans, it's worth noting the ID.4 was the only electric vehicle included in the test. The Buick Enclave and Chevrolet Traverse scraped away with 'acceptable' ratings while the Honda Passport, Honda Pilot, Hyundai Palisade, Jeep Wrangler 4-door, Kia Telluride and Nissan Murano were deemed merely 'marginal' in the tough new test. Only two models — the Mazda CX-9 and Volkswagen ID.4 — earned a "Good" rating in every test category.  Interestingly, the Jeep Wrangler would have scored a 'good' rating if it were equipped with side airbags for the rear seating positions. It would likely be an engineering challenge to equip its removable top and/or doors with airbags, but the lack of that safety feature allowed the head of the rear passenger dummy to hit the vertical support of the top. Otherwise, the Wrangler scored good ratings across the board. The new Ford Bronco, which makes more allowances for side-impact safety, has not yet been tested.  The popular Hyundai Palisade and Kia Telluride SUVs stand out in the test with 'poor' ratings for driver pelvis injuries. The Nissan Murano, a vehicle last redesigned for the 2015 model year, was the only vehicle tested that received a 'poor' rating for its structure and safety cage. Videos of the tests of 12 of these 18 SUVs can be found on the IIHS' YouTube page. Related video: Green Buick Chevrolet Ford Honda Hyundai Infiniti Jeep Kia Mazda Nissan Subaru Toyota Volkswagen Safety Crossover SUV IIHS Insurance Institute for Highway Safety