Mazda has spent most of the last decade arguing that the petrol engine still has a lot left to give. Its first big bet, Skyactiv-X, was meant to bring diesel-like economy to a petrol engine. Its next one, the Mazda Skyactiv-Z engine, is meant to make a petrol hybrid clean enough for the toughest emissions rules coming in Europe and North America 5.
This refreshed article looks at what Skyactiv-X promised and delivered, how other carmakers have tried to save combustion, and what Mazda has said about Skyactiv-Z so far. It also covers what the timing means for buyers here, because the first car to get the new engine is a model many Australians already drive.
What Skyactiv-X promised
Mazda announced Skyactiv-X in August 2017 as part of a long-term technology plan it called Sustainable Zoom-Zoom 2030 1. The engine used a combustion method Mazda named Spark Controlled Compression Ignition, or SPCCI 1.
Compression ignition is how a diesel works: the fuel and air mixture is squeezed until it lights by itself, with no spark. Doing that reliably with petrol is hard, because the moment of ignition is difficult to control. Mazda's answer was to keep a spark plug and use it to trigger and time compression ignition, switching between the two modes as conditions changed 4.
The claims were bold. Mazda said engine efficiency would improve by up to 20 to 30 per cent over its existing Skyactiv-G petrol engine, with 10 to 30 per cent more torque, and it planned to introduce the engine in 2019 1. The release was careful to say the engine was still under development and the figures could change 1.
How it reached Australian showrooms
Skyactiv-X went into production in 2019 and was offered in the Mazda3 and the CX-30 2. To make compression ignition work across more of the rev range, the engine runs a very high compression ratio, listed as 16.3:1, and uses a small Roots-type supercharger to push in extra air 2.
In Australia the engine arrived in mid-2020 in a single top grade of each car: the Mazda3 X20 Astina, with a manual or automatic gearbox, and the CX-30 X20 Astina with all-wheel drive 3. It came with a mild-hybrid system that used a belt-driven starter generator and a 24-volt lithium-ion battery to assist the engine and recover energy when slowing down 3.
Overseas the 2.0-litre engine was rated at 132 kW and 224 Nm, with a Mazda3 fuel figure of 5.4 L/100 km on the WLTP test 3. GoAuto compared that with 6.6 L/100 km for the automatic 2.5-litre Skyactiv-G hatch in the same grade 3.
Why Skyactiv-X never became the default
On paper it was a breakthrough. In practice it stayed a niche choice. Motor1 summed it up in 2025 by saying Skyactiv-X had not been the roaring success Mazda had hoped for 4.
The reasons are easy to see from the hardware. A supercharger, a very high compression ratio and a combustion system that switches modes add parts and cost to a small petrol engine 2. In Australia it was only ever offered in the most expensive grades of two models, which kept volumes low 3. A buyer could also get close to its economy from a conventional hybrid.
Mazda has not abandoned the idea. Its stated plan is to expand the area in which SPCCI combustion can work, and to carry what it learned into the next engine 4. The aim, as Mazda UK's press office described SPCCI, was diesel-like economy and pulling power low in the rev range with the high revs and cleaner exhaust of a petrol engine 4. That goal has not changed. What has changed is the plan to reach it, which now leans on a hybrid system rather than on combustion alone.
Other attempts to reinvent combustion
Mazda is not the only maker trying to give the combustion engine a longer life. Two other approaches show how hard the problem is.
Burning hydrogen instead of petrol
Toyota announced in April 2021 that it was developing a hydrogen engine as a step towards carbon neutral mobility, and fitted it to a race car based on the Corolla hatch 7. The car's first race was the Fuji 24 Hours in May 2021 7. Toyota said a hydrogen engine emits no carbon dioxide in use, apart from minute amounts of engine oil burned during driving, as a petrol engine also does 7.
Burning hydrogen in air still produces oxides of nitrogen, so hydrogen combustion engines are not counted as zero emission 8. Storage is the other problem. BMW built 100 of its dual-fuel Hydrogen 7 between 2005 and 2007 9. It kept liquid hydrogen in an insulated tank of nearly 170 litres that had to stay at cryogenic temperatures, and a car left unused could lose its whole hydrogen load over 10 to 12 days 9. On hydrogen alone it could travel about 201 km 9.
Mazda has its own history here: it has developed rotary engines that burn hydrogen, including the RX-8 Hydrogen RE 8.
Getting rid of the camshaft
Swedish maker Koenigsegg took a different route. The Gemera, unveiled on 3 March 2020, was shown with a twin-turbocharged 2.0-litre three-cylinder engine that used a Freevalve system, meaning it had no camshaft 10. In July 2024 the company said that three-cylinder option would not be offered because of a lack of customer demand, and the production car uses a 5.0-litre twin-turbo V8 instead 10.
Each experiment moved the technology on. None has yet changed what most people drive.
Enter the Mazda Skyactiv-Z engine
Mazda first disclosed Skyactiv-Z in late 2024, and in March 2025 it set out where the engine fits in its plans 4. Mazda's own release calls Skyactiv-Z the core engine of its line-up in the era of electrification 5.
Here is what Mazda has said about it 5:
- it is designed to meet strict emissions rules such as Euro 7 5;
- it will be paired with a hybrid system Mazda has developed itself;
- the first car to use it will be the next Mazda CX-5, by the end of 2027 5;
- its combustion work will also be used to develop emissions control for the rotary engine;
- with it, the number of engine units in Mazda's range will be cut to less than half.
Motor1 reported that it is a 2.5-litre four-cylinder petrol engine, built to meet Euro 7 and the North American LEV IV and Tier 4 standards 4. Mazda's claim, as reported, is that simply modifying its existing engines to meet those rules would have cut their output by as much as 30 per cent, while Skyactiv-Z is meant to comply without that loss 4. Mazda also plans to carry the same combustion know-how into its larger six-cylinder engines 4.
The engine is said to rely on lambda one combustion. Lambda is the ratio between the air actually supplied and the air needed to burn the fuel completely, and a lambda of one means the mixture is exactly balanced 4. Mazda has not published the full detail of how it will reach its efficiency targets, so treat the claims as goals until cars are on sale.
Where the rotary fits
The rotary engine is still part of the story. Mazda reinstated a rotary engineering team, and it plans to keep developing the rotary as a range extender, as in the MX-30 e-Skyactiv R-EV, which uses an 830 cc single-rotor engine as a generator 4. Motor1 also reported that a more powerful two-rotor setup is being worked on, previewed by the Iconic SP concept 4.
Mazda's broader plan, announced at the same time, includes an in-house battery electric car due in 2027, built in Japan for global sale 5. Mazda describes the years up to 2030 as the dawn of electrification, and it intends to keep offering petrol, hybrid and electric options side by side through that period 5.
What it means for drivers in Australia
Mazda still sells a lot of cars here. It finished third in the 2025 new car market with 91,923 sales, and the CX-5 alone accounted for 22,742 of them 11.
The third generation CX-5 was due in Australia in mid-2026 with a revised, carried-over 2.5-litre petrol engine without a hybrid system, rated at 132 kW and 244 Nm 6. The Skyactiv-Z hybrid version was expected in late 2027 or early 2028, and Mazda Australia's managing director said the local business had asked for it earlier rather than later 6.
The timing matters because of the New Vehicle Efficiency Standard. Penalties under the scheme began accruing on 1 July 2025, and the carbon dioxide limits tighten each year, which makes thirsty turbocharged engines harder for brands to justify 6. Mazda's turbocharged CX-5 engine was dropped from the new model, largely because of its emissions 6.
If you are weighing up an engine choice now, our guide to when to buy and when to lease and our look at reliable hybrid cars in Australia are good places to start. Mazda's own story goes back more than a century, and our history of Mazda in Australia covers how the brand got here. When you are ready to look at what is on the market, you can browse cars for sale on Car Domain.
Until the Skyactiv-Z engine is on sale and tested, it remains a promise. You can read Mazda's own outline of the plan in its Lean Asset Strategy release, and its original Skyactiv-X announcement shows how big the last promise was.
Sources
- Mazda Motor Corporation, Mazda Announces Long-Term Vision for Technology Development, 'Sustainable Zoom-Zoom 2030', accessed 2 November 2026
- Wikipedia, Skyactiv, accessed 2 November 2026
- GoAuto, Mazda Skyactiv-X hybrid grades touch down, accessed 2 November 2026
- Motor1, Mazda's Skyactiv-Z Will Be 'The Ideal Internal Combustion Engine', accessed 2 November 2026
- Mazda Motor Corporation, Mazda Announces "Lean Asset Strategy" that Realizes Electrification of Multi-Solution, accessed 2 November 2026
- GoAuto, Mazda Australia asks for CX-5 hybrid ASAP, accessed 2 November 2026
- Toyota Motor North America, Toyota Developing Hydrogen Engine Technologies Through Motorsports, accessed 2 November 2026
- Wikipedia, Hydrogen internal combustion engine vehicle, accessed 2 November 2026
- Wikipedia, BMW Hydrogen 7, accessed 2 November 2026
- Wikipedia, Koenigsegg Gemera, accessed 2 November 2026
- NRMA, New car sales 2025: Australia's best-selling vehicles revealed, accessed 2 November 2026
