2012 Mazda 6 I Sedan 4-door 2.5l Black On Black on 2040-cars

Auto blog

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.

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.

A pair of Mitsubishis, the Mazda CX-30 and electric incentives | Autoblog Podcast #673

This week's Autoblog Podcast features Editor-in-Chief Greg Migliore and Consumer Editor Jeremy Korzeniewski as they debate the merits of the redesigned Subaru BRZ and Toyota 86 coupes and whether or not they are distinctive and powerful enough to attract buyers. The duo spends some time discussing ongoing EV and infrastructure legislation before turning their attention to a trio of crossovers. Greg muses about the 2021 Mazda CX-30 before Jeremy talks about the refreshed 2022 Mitsubishi Eclipse Cross and completely redesigned Outlander. We get nostalgic as we remember the dearly departed Pontiac GTO before wrapping the podcast up by making one more suggestion to a longtime listener who is shopping for a vehicle to replace her aging Honda Pilot. Autoblog Podcast #673 Get The Podcast iTunes – Subscribe to the Autoblog Podcast in iTunes RSS – Add the Autoblog Podcast feed to your RSS aggregator MP3 – Download the MP3 directly Rundown Cars We're Driving 2021 Mazda CX-30 2022 Mitsubishi Eclipse Cross 2022 Mitsubishi Outlander News 2022 Subaru BRZ revealed with 228 horsepower New Toyota GR 86 breaks cover as the Subaru BRZ's friendly rival Toyota 86, Subaru BRZ stay the course ... thatÂ’s OK. Biden aims to juice EV sales with tax credits, rebates: Will it work? 2004-2006 Pontiac GTO | Used vehicle spotlight Spend My Money Feedback Email – Podcast@Autoblog.com Review the show on iTunes Autoblog is now live on your smart speakers and voice assistants with the audio Autoblog Daily Digest. Say “Hey Google, play the news from Autoblog” or "Alexa, open Autoblog" to get your favorite car website in audio form every day. A narrator will take you through the biggest stories or break down one of our comprehensive test drives. Related Video: This content is hosted by a third party. To view it, please update your privacy preferences. Manage Settings.