Imagine a Mazda2 capable of 3.3 litres/100km in the combined cycle, about the same as a 150cc scooter.
Imagine no more - Mazda has released details of a new, direct-injection 1.3-litre petrol engine, on display for the first time at the Automotive Engineering Exposition being held at the Pacifico Yokohama convention centre near Tokyo.
The long-stroke (71 x 82mm) SkyActiv-G 1.3 uses a stratospheric, 14.1 compression ratio for high efficiency, especially under high load at low revs; Mazda quotes 62kW at 5400rpm and 112Nm at 4000.
To avoid knocking - an unavoidable problem with high-compression engines - it has piston cavities that create almost-spherical combustion chambers for consistent, even flame fronts, and multi-hole injectors for precise mixture control.
Dual-sequential valve timing, in combination with the high compression ratio, allows extremely delayed closure of the intake valves (called the Miller cycle) for improved cylinder filling, while narrower crankshaft journals, roller cam-followers and low-tension piston rings reduce internal friction by almost 30 percent compared to the current 1.3-litre Mazda2 engine.
But this isn't a pie-in-the-sky concept; Mazda plans to introduce the new engine to the Japanese market in the face-lifted Mazda Demio (known overseas as the Mazda2) by mid-2011. Driving through a continuously variable transmission with stop-start function, the company says it'll use only 3.3 litres/100km in Japan's 10-15 mode test cycle.
There's so much new technology here that Mazda has applied for more than 130 patents in relation to this engine.
SkyActiv is Mazda's umbrella term for new technology - including petrol and diesel engines, transmissions and new chassis - that improves driving dynamics as well as environmental and safety performance.