Mazda is out to save the internal combustion engine with Skyactiv-X. As a core part of the company’s Sustainable Zoom-Zoom 2030 long-term vision, Skyactiv-X combines the best traits of gasoline and diesel engines. Here are answers to 10 questions that’ll get you geeked out with Skyactiv-X.

#1. Why is Mazda banking on the internal combustion engine?

The move towards Electric Vehicles (EVs) may have been grabbing the headlines, but the internal combustion engine is here to stay. It will still power a majority of motor vehicles at least until 2035. Even with globalization at full swing, the world’s progress isn’t homogeneous. Technology doesn’t roll out at the same pace around the world and this is a challenge when just banking on electric or fuel cell techlogy.

With costs of manufacturing an internal combustion engine seen to dip below electric vehicles, Mazda says that around 80 to 85 percent of vehicles globally will still run on some sort of internal combustion engine either by itself or as a part of an electric and/or hybrid set-up 20 years into the future.


#2. So, why is it called Skyactiv-X then?

Simply because Skyactiv-X combines the best traits of their Skyactiv-G gasoline engine (horsepower, thermal efficiency, cleaner exhausts) with that of their Skyactiv-D diesel engine (fuel economy, torque, response).

Mazda has done this by employing that’s considered to be the Holy Grail of internal combustion engines: Homogeneous Charge Compression Ignition (HCCI) technology. Like a typical gasoline engine, HCCI injects fuel during the intake stroke (typical diesels do it during the compression stroke), but rather than using an electric discharge or spark to ignite a portion of the mixture, HCCI raises density and temperature by compression until the entire mix reacts spontaneously.

#3. How did Mazda beat other car makers to this technology?

Expect nothing less from the carmaker who persevered and rolled out the world’s only production rotary (Wankel) engine.

But seriously, Mazda has figured out a way around HCCI’s inherent problems (ignition problems at low temperature and engine knock at high temperatures) by using the spark plug to act as a control factor. This allows Skyactiv-X to switch between Spark Ignition (SI) and Compression Ignition (CI) seamlessly. Mazda calls this technology SPCCI or Spark Plug Controlled Compression Ignition. Instead of using the ignition to simply combust the air and fuel mixture like in a typical gasoline engine, the spark in SPCCI creates an “expanding fire ball” that acts as a piston that increases the pressure and the temperature thereby combusting the air/fuel mixture inside the cylinder.


#4. What are the advantages over typical gasoline and diesel engines?

Mazda has identified 2 obvious advantages: performance and fuel economy.

The most obvious advantage of Skyactiv-X is the improved performance, specifically responsiveness. In a typical gasoline engine, the throttle body is closed when idling. Yet, Skyactiv-X behaves like a diesel where the throttle body is always open. This allows for a more immediate response when hitting the accelerator. In their internal tests, Skyactiv-X reaches 40 km/h in less distance (1.7 meters) compared to a typical 1.5-liter turbocharged engine.

Another performance advantage of Skyactiv-X is that its power delivery is far more usable over a wider engine rpm range compared to a gasoline or diesel engine. While a diesel may have good low-end grunt and a gasoline may have good peak power, Skyactiv-X combines these two providing a flat torque curve from as low as 3,000 to around 6,000 rpm.

Next up, Skyactiv-X drastically improves fuel consumption because it remains efficient over a wider rpm range. Whereas other carmakers simply promote their engine’s peak thermal efficiency, Skyactiv-X remains thermally efficient across a wider range of loads. It also has a flatter fuel consumption curve as well. Mazda says it’ll be 20-30 percent more fuel efficient than the Skyactiv-G.

#5. How will it drive?

Mazda says that Skyactiv-X is just as responsive as the MX-5 equipped with the 2.0-liter Skyactiv-G motor (0-100 km/h in 7 seconds). Apart from its performance from a standstill, Skyactiv-X also has excellent in-gear acceleration.

And thanks to Skyactiv-X being more powerful yet more efficient over a wider rpm band, it reduces the need for a complex and (usually) heavier 8-, 9-, or 10-speed gearbox. In Mazda’s internal tests for example, the Skyactiv-X engine is just as fuel efficient at 100 km/h as it is at 80 km/h. If ever Mazda’s going to employ more forward gears than the current 6-speed AT, it’s all to give a more fun-to-drive feel.

Now, there are worries that Skyactiv-X may emit a diesel-like clatter given that it’s compression ignition. However, Mazda says that NVH will always be a top priority in their cars as well as providing for a “pleasing sound.”


#6. Will this mean the end of Skyactiv-G and Skyactiv-D?

No. Skyactiv-X will join as a third member of the Skyactiv engine family. As a matter of fact, Mazda says that Skyactiv-X doesn’t require any fancy new engine factory to manufacture. It can be built and assembled alongside the Skyactiv-G and Skyactiv-D engines all as part of their Monotsukuri operation. Also, they’re working on further improving their Skyactiv-G and Skyactiv-D as part of their Ideal Combustion Road Map. An upgrade to Skyactiv-G is expected to come in later this year or early next year, while the second-generation Skyactiv-D bows in around 2020.

#7. Will it cost more?

Yes it will. Mazda hasn’t given any ballpark figure yet, but expect Skyactiv-X to cost a bit more than their Skyactiv-G or Skyactiv-D engines.

Mazda has clarified though that it’s not going to be more complex in terms of design or maintenance. Since it won’t run on an extremely high compression ratio needed in a typical HCCI setup (36.8:1), the engine construction and even weight won’t differ too much from the current Skyactiv-G family (reports say Skyactiv-X will run on something like 18.0:1). Plus, it’s been tested on both 91 and 95 octane gasoline fuels so there’s no need to be picky with whatever fuel you’re loading.


#8. Is it future proof?

The nature of compression ignition itself promotes a very lean burn resulting in it passing stringent emission regulations such as Euro 6 probably without the need of a catalytic converter. Mazda says that its emissions can even be made cleaner if legislation requires it.

#9. When will it come out?

Real soon. Everything points towards the 2017 Tokyo Motor Show at the end of October when Mazda is expected to unveil Skyactiv-X alongside the all-new Mazda3.

#10. Is Mazda turning their head away from EVs or hybrids?

No. As part of their “Sustainable Zoom-Zoom 2030” initiative, Mazda will also roll out hybrid and EVs. However, they want to look at each market or region specifically. Looking at it through a “Well-to-Wheel” perspective, Mazda will not only look at a vehicle’s day to day usage, but everything from the source of electricity, to the vehicle’s material manufacture, assembly, and disposal.

Thus, they will only roll out hybrid or electric vehicles in markets where energy is generated via renewable sources and where a full lifecycle assessment is made. This includes the proper disposal of batteries and other hazardous components that are inherent with EVs or hybrids.