When the age of the internal combustion engine comes to an end, what do you think history will look back on as the pinnacle of its development?

An extravagant supercar with a thousand horsepower, perhaps?

I’d like to suggest that future scholars should set their sights on something more humble.  And they need only look as far as the new Mazda range for a couple of worthy candidates.

The crown is likely to be taken by the company’s new Skyactiv-X spark-controlled compression ignition engine that we’ll cover in a few weeks, but the remaining Skyactiv-G petrol engine is hardly short of innovations itself.

From its 2.0-litres, Mazda extracts a rather modest-sounding 122ps and 213Nm of torque.  But performance isn’t the primary goal, as its 10.4 second 0-62mph time can perhaps attest.

More telling is a CO2 emissions figure of 117 g/km and WLTP-certified economy of 44.8 – 45.6 mpg, although at the end of a week’s testing we’d averaged nearly 51 mpg from our car.

These numbers would be commendable from a diesel, but from a 2.0-litre petrol that we didn’t drive particularly economically, we can’t help but be impressed.

To achieve this, Mazda’s engineers have deployed a number of interesting technologies.

To start with, there’s the conventional stuff like revised pistons, higher pressure fuel atomisation, and an improved cooling system for faster warm-up.  But the big news is reserved for a pair of systems that make their debut on this latest Mazda3.

The first of these, cylinder deactivation, is something you’ll never notice.  During periods of light engine load such as cruising at a constant speed, the two outermost cylinders are shut down, effectively halving the size of the engine.

It happens completely imperceptibly, although a neat graphic on the dash-top display offers a clue, as does the jump in the instant mpg gauge.  At 1,500rpm or so, a slight vibration can just about be detected to indicate you’re being propelled by only two cylinders, but beyond this there’s no clue whatsoever.

Joining this is a 24-volt mild-hybrid set-up that uses a 600kJ lithium-ion battery to store energy captured during braking and deceleration, which can then power the car’s electrical systems or drive a small electric motor to assist the petrol engine.

The motor can’t drive the car by itself, but can provide additional torque during acceleration.  It also adjusts engine speed during upshifts to make gearchanges smoother, but perhaps the most obvious side-effect is the new stop/start system.

Most systems restart the engine when you depress the clutch, but Mazda’s system is cleverer – it waits until you lift off the brake pedal, at which point the electric motor spins the engine up to speed and restarts it, immediately and silently.

And then you’re off, free to sample the typically engaging handling and slick gearshift action, although spirited drivers will probably come away feeling a little underwhelmed by the power on offer.

Still, let the Mazda3 settle into its rather more relaxed groove and you’ll discover noise insulation levels that would be impressive for a car from the segment above, so quietly does the new 3 make its way down the road.

That’s a feeling backed up by the new cabin design, a model of calm serenity and simplicity.

A new widescreen display takes up station atop the dashboard, from which it provides a window into a new infotainment set-up that impresses with its ease of use and appealing graphics.

Personally I preferred the previous rotary controller, its smaller size felt more comfortable to use while its heavier weight offered a greater sense of quality.  It’s a shame, too, that the new wider display is no longer touch-sensitive, making inputting post codes something of a chore.

The new part-digital instrument cluster is about as clear as it’s possible to be, although I’m still a little baffled by the need for two fuel gauges.  The choice of trip computer information seems oddly limited, too, although Mazda more than makes up for it by including their excellent head-up display as standard across the entire Mazda3 range.

In fact, equipment levels are incredibly generous, with every model featuring automatic LED headlights (adaptive from the mid-range Sport onwards) with high-beam control, power-folding door mirrors, rain-sensing wipers, head-up display, electronic parking brake, satellite navigation with European mapping and five years of updates, Android Auto and Apple CarPlay, radar cruise control, blind spot monitoring, rear cross traffic alert, lane-keep assist, intelligent speed assist, and automatic SOS call assist.  Phew.

And I’ve not even mentioned the fact it looks fabulous.

New Mazda3 Prices

Prices or the new Mazda3 start at £20,595 for the entry-level SE-L, while a mid-range Sport Lux can be yours for £22,795.  A 1.8-litre diesel is available for £1,800 more, while the 180ps Skyactiv-X is a roughly £2,000 uplift.  A Saloon model is also offered, although not with the 2.0-litre petrol engine.

Entry-level Price£20,595Price as tested£25,145
Engine1998cc 4-cyl petrolTransmission6-speed manual
Power122ps @ 6,000rpmTorque213Nm @ 4,000rpm
0-6210.4 secsTop speed122 mph
Economy (WLTP)44.8-45.6 mpgCO2119 g/km
Dimensions4460 x 1795 x 1435 (LxWxH)Kerb Weight1439 kg