DIESEL engines have long been the choice of buyers of Volvo’s flagship XC90, but with customers moving away to petrol and electric powered vehicles there’s a new powertrain for this evergreen giant of the SUV market.

Volvo call it the B5, and the diesel version of the XC90 is the first model to offer the company’s new mild-hybrid engine.

The B5 combines Volvo’s established 2.0-litre 235hp diesel engine with a 48-volt battery, a kinetic energy recovery system and an integrated starter generator.

The result is that this system improves fuel economy – by up to 15 per cent in real-world driving to more than 40mpg – and produces lower NOx emissions than the outgoing D5 XC90 it replaces.

It’s clever stuff and a welcome alternative to the petrol/electric/plug-in hybrids currently on trend.

In simple terms, energy captured by the system when the car brakes or decelerates is stored as electricity in the battery. This is used to supplement the engine’s performance when accelerating and to power ancillary functions such as the headlights and audio system.

The same technology is being applied to petrol engines in the XC90 line-up.

The B5 also gets an updated eight-speed automatic transmission, which brings improved fuel efficiency and superior gearshift quality. Acceleration from a standstill is sharper, too, thanks to a greater torque capacity in the lower gears. How does 0 to 62mph in 7.6 seconds sound?

The beauty of this system is that you, the motorist, do not have to do anything but drive it like a conventional D5. There are no switches to press, no graphics to read, and no plugs to mount.

For what is a heavy car, the B5 engine does an impressive job in responding to inputs, and rides in a sedate, quiet fashion. Comfort comes as a given.

There’s no doubt that the B5 is greener than the D5, and it is also more powerful. It is also smoother and the ideal next purchase for those fans of the XC90 reluctant to switch away from a diesel engine.

What’s more, the B5 arrives with some styling changes focusing on detailing to the seven-seat XC90. There’s a new grille and lower front bumper designs. The air intakes also have a fresh look and new alloy wheel designs have been introduced. All XC90 versions also now come with integrated roof rails and dual integrated exhaust tailpipes as standard.

R-Design variants have been given an even more purposeful look with a new black high-gloss finish for the exterior trim, including the door mirror casings, window frames and roof rails. Inscription-grade XC90s feature a new chrome strip that runs the full width of the rear bumper. There are also new exterior paint options.

Across the board, the XC90 is now fitted with two USB ports in the cabin as standard. Momentum-grade models add power adjustment for the front passenger seat and the T8 Twin Engine versions are now supplied with a purpose-designed bag to store the recharging cable.

The XC90 has an impressive standard specification. Key features include the Sensus nine-inch multimedia touchscreen with voice-activated control, navigation system and access to the Volvo On Call connected services platform. Extensive systems warn of and help avoid many common accident risks, and provide optimum protection if a collision does happen. Other equipment fitted as standard includes a power-operated tailgate, LED headlights, a rear parking camera and keyless entry and start

The XC90 range is available in Momentum, R-Design and Inscription versions – each also available in more highly specified ‘Pro’ form. Every XC90 comes with all-wheel drive.

AT A GLANCE

Volvo XC90 B5 diesel AWD Inscription

Price: £66,550 (XC90 range from £52,235)

Engine: 2.0-litre turbocharged diesel producing 235hp

Transmission: Eight-speed automatic driving all wheels

Performance: 0 to 62mph in 7.6 seconds; top speed 137mph

Economy: 37.7 to 44.1mpg

CO2 emissions: 154 g/km

RATINGS

Performance: ****

Economy: ****

Ride/Handling: *****

Space/Practicality: *****

Equipment: *****

Security/Safety: *****

Value For Money: ***

OVERALL: ****