Mazda’s isn’t done with the diesel. No, even though demand for the powertrain dropped 34 percent last year and Euro 7 emissions rules are poised to make diesels more expensive than ever, the Japanese automaker is still committed.
It has promised that by next year it will offer a six-cylinder, 3.3-liter diesel in CX-60 flagship that is Euro 7 compliant, despite not knowing how stringent the rules will be.
“Mazda will fulfill the Euro 7 emission standards with the new diesel engine,” Joachim Kunz, senior manager of technical development at the Mazda Europe R&D center, said during a CX-60’s unveiling this month.
Kunz is aware that Mazda’s engineers face a moving target given that EU policy makers haven’t settled on how tough the targets will be, particularly for nitrogen oxide (NOx)
“This will be most likely be the last generation of internal combustion engines, so we will prepare for the toughest expected target and then adjust using after-treatment solutions,” he said.
Kunz said Mazda is prepared to invest more and forsake profits to offer the engine while the customer might have to accept a less power engine.
To leave its engineers more wiggle room to work with, Mazda purposely chose a large displacement for the engine. No other light vehicle manufacturer in Europe offers a diesel with a displacement topping 3.0 liters.
“Having a 3.3-liter engine means we want to be on the safe side for torque and power,” Kunz said adding the Mazda believes the forthcoming diesel will offer fuel economy figures comparable with a turbocharged four-cylinder engine with the same power output.
To achieve this Kunz said the diesel needs to have excellent combustion efficiency, so the more of the heat it produces is translated into power and less heat is lost to the cooling system.
“To get low NOx emissions we need low combustion temperatures,” Kunz said. “Having a bigger engine keeps temperatures lower, which is good both for reducing the heat loss and for cutting the raw NOx emissions. This in turn will enable us to have a simpler after-treatment system.”
Kunz said the diesel will include a selective catalytic reduction (SCR) system “to show the customers that we are making ever effort to reduce NOx.” The SCR, which converts NOx with the aid of a catalyst into diatomic nitrogen and water, will be smaller and require less frequent urea refills by the customer, Kunz said.
Kunz said Mazda plans to offer the CX-60 diesel to its sales companies throughout Europe, with the possible exception of Norway, where electric cars already account for the vast majority of car sales.
