For a Japanese manufacturer like Mazda, the bi-annual Tokyo Motor Show would ordinarily be a chance to flex its creative muscles
A production car world debut, a home market vehicle to excite the local media and a wacky concept to promote future styling plans – these are what we would normally expect to see. Instead, this year’s tighter budgets meant we were treated to a car previously seen at the Frankfurt expo and the launch of something called the Mazda Sky concept, which wasn’t even a vehicle.
On paper – because there was nothing to see – Sky was marketing puff, with messages about ‘providing driving pleasure for all our customers.’ But the devil, or in this case, the interesting stuff, was in the detail. Sky is actually three new advanced powertrain technologies, one of which is a clean-burn diesel engine. The other two focus on petrol powerplants and an automatic transmission. But together, the target is to achieve a 30 per cent boost in fuel economy for all Mazda vehicles sold globally by 2015, compared to 2008 levels. For diesels, the goal is extremely specific – bosses want a Mazda6 to deliver the fuel economy of a Mazda2. That means pushing the D-segment saloon’s combined figure skywards from 50mpg to nearer 70mpg.
The new diesel engine is currently known as the Sky-D, though it will be rechristened when production and sale begins in 2011. The focus is on improving the combustion process – also known as its thermal efficiency – so the vehicle travels further on the same amount of fuel. Mazda believes that it’s necessary to reduce energy losses in four areas – pumping, mechanical friction, cooling and exhaust gas. The key to this is getting closer to perfection in as many of the elements of engine function as possible. These include effective intake volume, combustion duration and timing, and the load and coefficient of friction.
Reducing NOx and soot emissions is also part of the SKY-D equation. In a conventional diesel, it’s difficult to start combustion with the best timing for thermal efficiency, while simultaneously suppressing NOx and soot. But by better management of the process, coupled with a host of component tweaks, Mazda believes it’s made a technological breakthrough. The company claims that the result is a 20 per cent improvement in fuel economy over the MZR-CD 2.2-litre turbodiesel that’s currently found in the Mazda6 and others. Torque across the rev range is also improved.
The Sky-D engine also incorporates new technology for efficient treatment of particulates in the exhaust gas. This includes a world-first catalyst activation mechanism. It means the DPF regeneration interval has been doubled, yet the regeneration process time is a third shorter.