Featured Mazda competes for thermal efficiency against Toyota with Skyactiv-Z

I like that companies like Mazda are trying to make engines more efficient. But I do like that Toyota makes a very aerodynamic car, the Prius. Their sedans are pretty sleek too. Too bad they don't offer an aerodynamic cargo-carrying design anymore.

People seem to think that you can take any shape and make it aerodynamic. But I remember all too well when Mazda killed their Mazda 6 Wagon in favor of the CX-5, yet the CX-5 got worse fuel mileage even being tuned down to produce less horsepower and was smaller, having less passenger and cargo space.

My thoughts are, first, get rid of the boxy crossover design if you want fuel efficiency and replace it with something that makes more aerodynamic sense (Drag = Frontal Area x Cd x Fluid Density x V^2). Then worry about engine efficiency.

 

Mazda has been willing to tolerate more risk on advanced engine technology for decades.

Their rotary engines, the Miller-cycle engine they used in the late 80s, direct-injection, gasoline compression engines, and their "starterless" engine are all examples.

Not always successful in these endeavors, but I give them a lot of points for trying.

Our other car is a Mazda 6 Sedan. I would've camped out overnight for the station wagon if they'd still offered it. But sadly now the sedan is discontinued as well, which probably means it's our first and last Mazda- we just don't buy crossovers or SUVs.

 

How efficient something is turns on what the need is. Grocery getter? Pulling a trailer? Traveling just a couple blocks?
Putting the same displacement in an internal combustion engine though?



Isn't that why Volkswagen put a diesel in the car rated with the highest efficiency ever? Even over the past 1½ decades?

Volkswagen 1-litre car - Wikipedia

Plug-in hooked up to turbo diesel wins. Gets over 200mpg. 250 units sold. Oh! too expensive? There you go, not accounting for cost. Here's to hoping Mazda is successful, but again, how it's packaged comes into the equation. Yet it isn't going to beat a bicycle when it comes to efficiency

 

Seems to be the next gen of the Skyactiv-X. That was a hybrid spark and compression ignition gasoline engine. Like a diesel, it was lean burning; as high as 29.4:1.(2020 Mazda3 Skyactiv-x v Mazda3 Skyactiv-G comparison test) Mazda never released a thermal efficiency to the public, but there are estimates.

This has it at 41% to 42%. Mazda Skyactiv-X Market and Technology Analysis
EPA modeling in only at 34% to 37%, the efficiency island is large(page 27).https://www.epa.gov/sites/default/files/2018-10/documents/high-efficiency-ic-engine-sae-2018-04.pdf

 

The devil is in the details.

 

Can't tell if that's tongue & cheek are not but a diesel or gasoline engine can be just as dirty or clean as the other - modernly.
.

 

There's more energy in diesel than there is in gasoline, but the diesel cycle is also slightly more efficient than the gasoline engine. It's not as though any of them don't have plenty of room for improvement, though.

Engine efficiency - Wikipedia

 

someone hasn't been keeping up with current events it would seem. Yes, over the past decade things have changed & both types of fuel burners continue to get better.

Are Diesels Cleaner than Gasoline Engines? - Achates Power

... but who knows, in a few more years maybe gasoline will close in on diesel cleanliness & efficiency again.

.

 

Using spark assisted compression ignition in the X and Z Skyactivs is Mazda's attempt to get the efficiency of the diesel cycle with gasoline.

Diesel cars have been meeting gasoline emission regulation levels for years in the US. Those with working exhaust filters likely emit less particulate pollution than gasoline cars on our roads now. Other markets are requiring such filters on gasoline cars today. The pursuit of efficiency through lean burn could be tomorrow's gasoline engines need the same pollution controls as diesels.