Mazda brings a new CX-5 diesel SUV to the US – but why?

When Mazda invited us to a roundtable on powertrain technology at the New York auto show this year, it was easy to say yes. After all, the company is behind a recent breakthrough in internal combustion engine technology. So you can imagine my surprise when the subject that preoccupied Mazda was the introduction of its Skyactiv-D diesel engine in the North American market, under the hood of the (excellent) CX-5 SUV. Intrigued, I had to find out why the Japanese manufacturer was taking this step.

The fall of Diesel

You can be forgiven for thinking that "diesel" was now a dirty word. For a while, this liquid hydrocarbon fuel has seemed to be an important tool in the fight against climate change. After all, diesel engines are much more efficient than gasoline engines, so you can move further between gas stations and emit less CO.₂ by doing it. But CO₂ It's not the only problematic component of diesel exhaust gases. A more immediate danger posed by diesel exhaust gases is the soup of nitrogen oxides (NOx) and particles resulting from combustion. While CO₂ our climate will ruin our climate in the coming decades, NOx damage people's lungs today. And it's the NOx that is responsible for the diesel drop.

Or, more specifically, the industry has largely lied to regulators regarding the exact amounts of NOx emissions from their cars. The most famous culprit was the Volkswagen group. In 2015, he was caught lying to the federal regulatory authorities in the United States and the penalties were severe. The executives were continued. Hundreds of thousands of cars had to be redeemed from their owners, fines rising to billions of dollars and an entirely new business plan were created to quickly electrify one of the three more major auto companies of the world from here the middle of the year. next decade.

VW however was not the only bad actor; Other builders in Europe and Japan have also been the subject of investigations. But Mazda has not been among them. Its Skyactiv-D engines have been on sale in Japan, other Asian markets and in Europe for quite some time, in various sizes, but the 2.2-liter diesel engine is only bringing to these shores. To comply with US emissions rules, the engines feature an urea exhaust (adblue) as well as a NOx storage catalyst.

Work with regulators

According to Ichiro Hirose, Mazda's general manager and powertrain development manager, when the company originally planned to introduce the engine to the United States, it would be without this post-processing. But the tests conducted by the company in the field have proved that it was a necessary addition.

"We thought that VW had to have a technology that no one knew existed to respond to NOx emissions without advertising," he said. As we know, this was not the case. "We had to think about all the possible driving conditions and cover the real cases of NOx emission increases, so we had to add these devices." At first we did not have the same understanding with the authorities. but we have worked with them to look at different modes of conduct, which is a very time-consuming process, "he said.

It is certainly possible to make a diesel engine compliant with emissions regulations – it only costs a little more. A more important question – at least in my mind – is: why bother? After all, Mazda already has the highest average fuel efficiency of its fleet compared to automakers selling their vehicles in the US, and has done so without diesels, hybrid vehicles or battery-powered electric vehicles. Its new Skyactiv-X engine uses diesel-type tricks to increase the efficiency by 20%, but the US approval for this powerplant is not yet complete. But that's not the reason, according to Hirose.

"We believe that in the United States, some customers still want a unique diesel-fueled sensation." With Skyactiv-G [the current gasoline direct injection engine], Skyactiv-D [the diesel]and Skyactiv-X, we have selected the right powertrain for the market and the right use, "said Hirose. With an SUV [like the CX-5]it requires a lot of low-end torque. Customers tend to need a large towing capacity. Diesel is therefore still very suitable for these applications. On the other hand, the Skyactiv-G turbocharger version is suitable for customers who want maximum power.

"With Skyactiv-X, we want to capitalize on uniqueness.This engine also uses a forced induction, but the boost is not used to generate a significant torque, it improves efficiency," he said. he continued. "During the development process of Skyactiv-X, we also learned things that we can also apply to -G and -D Our vision is that there will be a synergy between the three powertrains of the range. . "

Some of the lessons learned during this development process saw the Skyacticv-D engine's compression ratio increase from 14: 1 to 14.4: 1.

Nevertheless, Mazda does not expect to sell as many CX-5 diesels. Globally, this represents about nine percent; Here in the United States, Mazda targets a participation rate of 10%.

Eventually, the speech turned to electrification, but only briefly. Hirose revealed that Mazda plans to introduce a BEV next year. It will be a vehicle developed by Mazda, not a product of the partnership with Toyota, and the company is still in the process of deciding which markets it will or will not be for sale. "We will not announce anything until the end of the year," he told us.