MANAGING EXECUTIVE OFFICER; POWERTRAIN DEVELOPMENT, VEHICLE DEVELOPMENT AND PRODUCT PLANNING MAZDA MOTOR CORPORATION
FOR enthusiasts, the engine or “heart” of a car is just as important as its design, if not more important. After all, a car’s powertrain exerts enormous influence on the car’s overall character and performance. Powertrains are something that Ichiro Hirose knows well. The 57-year-old, who marked his 34th year with Mazda last month, has spent most of his career working in the carmaker’s engine-related divisions. Although Hirose-san joined Mazda in 1984, his first significant appointment only came in 2009, when he was made general manager of the Engine Design Engineering Department. In 2011, he became the deputy general manager of the Powertrain Development Division.
The following year, he was sent to Germany where he assumed the post of vice-president at Mazda Motor Europe. After a two-year stint, he returned to Powertrain Development, a division he has stayed in for the past four years.
Hirose-san’s division is certainly making waves for Mazda. At the 2017 Tokyo Motor Show, the manufacturer announced Skyactiv-X, a new petrol engine that promises huge gains in performance and efficiency through the use of very high compression ratios. Torque had a quick chat with the veteran engineer, who not only explained the technology to us, but also mentioned the return of rotary engines to future models.
How does Skyactiv-X work?
It is the first commercial petrol engine that primarily utilises high compression to ignite the fuel-air mixture (like a diesel engine) in the cylinders. In effect, it combines the benefits of a petrol
engine and a diesel motor. Petrol engines have smoother delivery and greater horsepower, whereas diesel units offer higher efficiency and more low-end torque.
Mazda’s current Skyactiv-G petrol engines have a compression ratio of 13:1. The new Skyactiv-X engine will exceed this ratio. Unfortunately, due to confidentiality issues, I cannot provide the figures.
What sort of efficiency gains can Skyactiv-X offer?
Compared to a current Skyactiv-G engine of similar displacement, a Skyactiv-X engine will improve fuel economy by 20 to 30 percent, while producing 10 to 30 percent more torque, too.
How long has Skyactiv-X been in development?
It has been three years since we started. But we will only launch it in 2019, so the total development time is four years.
Since Skyactiv-X uses higher compression ratios compared to Skyactiv-G, will the engine need high-octane petrol? Is there a minimum RON requirement?
Usually, high-compression engines require higher octane to prevent premature detonation, which is known as “knock”. However, we designed Skyactiv-X to take advantage of this “knock”. Therefore, lower RON means better fuel economy.
That said, we engineered Skyactiv-X to use a minimum of 91 RON. The advantage is that this grade of fuel is more widely available not just in the ASEAN region, but globally, too.
After 2025, all new Mazda models will either be petrolelectric hybrids or fully electric. Will the latter models have range-extenders?
Our first full electric vehicle will be introduced in 2019, and it will have a rangeextender, which will be a rotary engine.
How big will this rotary engine be?
[Laughs] Right now it is a secret. But it will be a rotary engine.
What’s the minimum expected range from Mazda’s pure electric vehicle?
We’re still considering this. The range will also depend on how advanced battery technology will be then.
Having driven various electric cars, you must have found that no matter the brand, the power delivery is similar. How will Mazda differentiate its models?
We will ensure that our electric car follows the Jinba Ittai (“horse and rider are one”) handling philosophy, so that it stands out.
SKYACTIV-X IS DESIGNED TO TAKE ADVANTAGE OF “KNOCK” AND LOWER-OCTANE FUEL.
The Kai concept previews the nextgeneration Mazda 3 hatchback, which will be powered by a Skyactiv-X engine.