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posted by Fnord666 on Wednesday January 31 2018, @12:50AM   Printer-friendly
from the under-pressure dept.

Submitted via IRC for AndyTheAbsurd

It's called Spark Controlled Compression Ignition, and Mazda made it work.

Despite rumors to the contrary, the internal combustion engine is far from dead. Recently we've seen several technological advances that will significantly boost the efficiency of gasoline-powered engines. One of these, first reported back in August 2017, is Mazda's breakthrough with compression ignition. On Tuesday, Mazda invited us to its R&D facility in California to learn more about this clever new Skyactiv-X engine, but more importantly we actually got to drive it on the road.

The idea behind Skyactiv-X is to be able to run the engine with as lean a fuel-air mixture (known as λ) as possible. Because very lean combustion is cooler than a stoichiometric reaction (where λ=1 and there is exactly enough air to completely burn each molecule of fuel but no more), less energy is wasted as heat. What's more, the exhaust gases contain fewer nasty nitrogen oxides, and the unused air gets put to work. It absorbs the combustion heat and then expands and pushes down on the piston. The result is a cleaner, more efficient, and more powerful engine. And Skyactiv-X uses a very lean mix: a λ up to 2.5.

Source: https://arstechnica.com/cars/2018/01/mazdas-skyactiv-x-shows-the-internal-combustion-engine-has-a-future/


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  • (Score: 2) by turgid on Wednesday January 31 2018, @09:15AM (2 children)

    by turgid (4318) Subscriber Badge on Wednesday January 31 2018, @09:15AM (#630880) Journal

    Only the first lot. I had one of the old RX-7s with the 12A engine and it did over 127k miles before the rotor seals went.

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  • (Score: 0) by Anonymous Coward on Wednesday January 31 2018, @09:24AM (1 child)

    by Anonymous Coward on Wednesday January 31 2018, @09:24AM (#630883)

    Unfortunately the old engines set the reputation for the decades to follow. Sort of the "Java is slow" of the car industry. And Mazda had another run of bad engines in the mid-90s. But from about 1976 to 1990, some of the best engines ever made. Make sure they have a supply of something resembling oil and coolant and they'll last 200,000 miles every time.

    • (Score: 0) by Anonymous Coward on Wednesday January 31 2018, @03:08PM

      by Anonymous Coward on Wednesday January 31 2018, @03:08PM (#630974)

      I used to tune those early wankels that had 2 distributors w/points. If they weren't set up exactly right you'd get blown mufflers from exhaust backfires. The apex seals on the early engines were failing at 30k miles, and later turbo-wankels were having problems with cracking cases and manifolds.