Matt Kimberley, PA motoring writer, says a new turbo diesel engine boosts the appeal of Nissan's popular crossover.

The Qashqai has been one of the great recent success stories. Crossovers – half-hatchback, half-sport utility vehicle – are now everywhere but the Qashqai set the ball in motion for what has proved to be one of the most popular types of new car in the UK.

It had fallen behind in some ways though, chiefly efficiency – that catch-all quality that includes fuel economy, road tax costs and general environmentally friendliness. The range lacked a real star efficiency performer while newer rival cars had got their eco-acts together.

So what Nissan needed to do was give the Qashqai – and the seven-seat Qashqai +2 – a new engine, one that could compete with the best in class. What it's actually done is to build an engine that in some important ways is better than the competition.

The only caveat with most modern eco-friendly diesels in affordable family cars is that they're relatively low power, and therefore a bit of a compromise on the road. Nissan, with 'alliance' partner Renault, has designed a 1.6 turbo diesel with the exact same amount of torque as the old 2.0-litre it replaces.

It's lighter, more cleverly packaged and incorporates significant – if simple-sounding – technologies that help reduce overall CO2 output to 119g/km – enough to drop it into the �35 a year road tax band.

To look at and sit in, the Qashqai hasn't changed much so all the qualities that made it the best-selling crossover in its class are still there. The Sunderland plant that builds them has produced more than a million already, operating 24 hours a day to keep up with demand.

What's so significant about the new engine is that it's much better for drivers than some other eco-diesels. There's useful acceleration in the first five gears, and sixth acts as an overdrive to keep revs – and fuel consumption – as low as possible.

The one compromise with smaller-capacity engines is that they have less natural urge when the turbo isn't active, meaning that off boost the 1.6 dCi is more easily stalled. It just asks for a minor recalibration in driving style – a gentler right foot or keeping the engine over 1,500rpm.

Nissan has also tried to quieten the typical diesel rattles – at low speeds there's no hiding the diesel noise, at speed it all quietens down nicely.

It's then that you notice some wind noise around the wing mirrors.

On rough roads the car rides as well as ever, biased towards a soft set-up which is good news for UK drivers. The suspension seems quiet and well damped, and overall it's a comfortable drive.

The cabin is one of the less adventurous in the class in terms of styling. There's nothing wrong with it at all and the quality seems quite high, but it's more sober in demeanour than you might expect.

Potential customers will be happy to see that the new, and generally excellent 1.6-litre diesel engine will be available in its most economical Pure Drive guise – two-wheel-drive with stop/start technology – in all four trims from Visia up to Tekna.

There's also the option to link the engine with four-wheel-drive, which gives the car a little extra ability in low-grip situations but pushes the road tax back up to �120 and dents fuel economy a bit.

Although the 2.0-litre dCi diesel has been replaced in the main, it will carry on for now as the powerplant for the four-wheel-drive automatic Qashqai, due to its inherent extra off-boost torque being a better fit for the gearbox.

Also worth a note in the revised cars is the Around View Monitor. Four cameras, one on each side and end of the car, create a bird's eye view of the car's surroundings, allowing you to navigate and park at very slow speed even with the windows completely obscured – I tried it but probably best not to have a go yourself at the supermarket!

Although you might find people summing up the changes as 'just a new engine', in the context of our extortionate fuel prices the revised Qashqai makes more sense than ever in a marketplace where it ruled the roost. It had been in danger of being knocked off its perch, but the new engine puts it at the top of the tree.