Mazda's new fuel efficient engine..
 

They claim it will get comparable mileage to a same sized diesel.

Mazda introducing breakthrough 'spark-less' gasoline engine in 2019 | Fox News

It's great to see a small manufacturer such as Mazda come out with this new technology. I'm just wondering if Mazda should have invested in electric cars or hybrids than this technology. Time will tell.

Sounds promising, but will it deliver up to 30% better economy in real world conditions I wonder? They also plan to roll out their electric cars by 2019 too,

Mazda reveals electric vehicles are due in 2019 | Next Green Car

Homogeneous charge compression ignition have been getting worked on for a number of years now. Honda have been doing a lot of work with them for use in hybrids.
Their disadvantages include difficult cold starting and poor emissions (just what you need for a hybrid). They also have considerably greater wear. The main advantage is a 30% increase in efficiency.
It will be interesting to see what Mazda have achieved.

The Skyactiv gas engines ran 14 to 1 compression, direct injection at 200 atmospheres, high volume cooled EGR, turbocharging, multi event injection during each combustion stroke(5 individual injections).

True HCCI means the mixture must be very consistent (thus the homogenous term) when compression ignition occurs, which seems to follow the evolution of the design.

The end result is a 25% increase in thermal efficiency, providing diesel like MPG on gasoline, which has a lower energy density, thus more efficient.

True HCCI produces virtually no emissions requiring any after treatment of exhaust byproducts.

Here's a good video on the topic: https://www.youtube.com/watch?v=WBkfOUaEcWM&t=4s

If the engine delivers on its promise, without any drawbacks, then this will be a game-changer for ICE. Hopefully, it'll runs on regular unleaded, rather than the much more expensive (in Canada, where I live) Super.

Just as a data point, the pump price of diesel where I live has been about 5%-6% lower than regular for the past 2 years. I'm still enamored with my diesel engine. Not only do I save at the pump with lower fuel prices (17% lower than premium), I also get much better MPG. Double win for diesel.

Here in the UK the price of diesel is at least the same as petrol, and usually higher. Add to that the way the government and the BBC (some say one and the same) are stigmatising diesels, the bottom is about to fall out of the used diesel market, or at least that's what I feel.

Too much demonising of diesels in the Motor press sadly, and our easily influenced gullible public audience will go along with anything the government says. When you study the facts, modern diesels are far cleaner than petrol engines, the problem lies with commercial and older diesels. BMW for example have launched a "scrappage scheme" for older diesels but defended modern diesel tech too.

"The BMW Group says modern, efficient diesel engines ensure lower CO2 emissions and therefore make an important contribution to protecting the environment. In addition, when it comes to many unwanted emissions, diesels are just as clean or even cleaner than petrol engines. This can certainly be said of particulate, hydrocarbon and carbon monoxide emissions, meaning that three of the four major diesel pollutant issues have been resolved and no longer have any adverse effect on air quality. This is why the BMW Group is calling for objective discussions based on facts and scientific evidence"

More information here: https://www.greencarguide.co.uk/2017...appage-scheme/

Draigflag: People tend to be lazy and prone to confirmation bias. One example is the issue of emissions and pollution.

The narrative is that diesels pollute more than gasoline engines. Most folks remember, or are seeing, diesels belching black smoke. That's bad. Meanwhile, gasoline cars don't belch black smoke. Diesel, "dirty"; gasoline, "clean". It's easy for most people to swallow that story.

One problem is that "pollution" isn't one thing. It's any number of undesired things. In the previous example, we were looking solely at carbon nanoparticles, or "soot". That's easily addressed with a Diesel Particulate Filter, or DPF. Diesels emit more oxides of nitrogen, commonly called NOx, compared to a similar gasoline engine. That's bad. But gasoline engines emit a lot more CO2, or Carbon Dioxide. And that's bad, too... right? Except if you believe it's harmless, does not contribute to global climate change, and is actually good. It's plant food, so the more CO2 we produce, the better it is for greening the planet (say mouthpieces of the coal and oil industries, which have profound influence in governments).

Most folks don't know that CO2 is poison to us humans. They don't know that because they think binarily: Does a tiny bit of CO2 kill you? No? Then it's harmless. Just some facts about CO2:

• In concentrations as low as 1,000 parts per million (PPM), that's just 0.1%, humans get drowsy and complain of "bad air"
  .
• In concentrations as low as 2,000 PPM, or 0.2%, humans can get headaches and find it difficult to concentrate
  .
• At just 5,000 PPM, or 0.5% (that's one half of one percent), it's considered a workplace hazard, and there are exposure time limits for safety reasons.
  .
• At 40,000 PPM, or just 4% concentration of the air we breath, people lose consciousness and die.

You won't hear these numbers from the "CO2 is perfectly safe" crowd. Lazy humans are easily fooled, easily manipulated, often by appealing to their fears and uncertainties.

Getting back on topic: I hope Mazda can pull it off. They did a great job with the rotary engine; maybe they can do the same with this concept.