New Volvo S80 and V70 DRIVe with 1.6-liter Diesel Return 4.5lt/100km - 52.3 mpg US with 119g/km CO2

Thanks to a few minor tweaks, Volvo has managed to further reduce CO2 emissions and improve fuel efficiency on its S80 and V70 DRIVe models from the 2009MYs 129 g/km and 4.9 lt/100 km (48mpg US) to 119 g/km and 4.5 lt/100 km (52.3mpg US) on the 2010MYs respectively.

Both cars continue to use a 1.6-liter diesel with 109HP and 240Nm of peak torque that's hooked up to a five-speed manual gearbox.

However, Volvo's engineers employed a smart battery recharging system that 'forces' the alternator to charge the battery only when the engine is operating at low load (e.g. when driving downhill), while they also redesigned the tensioner and alternator pulleys.

"Smart battery recharging is the most important measure," says Ulf Nordström, Technical Project manager at Volvo Cars.

"It is primarily thanks to this that we have dipped below the 120-gram level that gives car owners tax breaks and other benefits in a number of European countries. What is more, one might say that we offer the normal driver one free tank of fuel a year," Nordström added.

The Swedish automaker said that the reduction in fuel consumption from a combined 4.9 lt/100 km to 4.5 l/100 km means that someone driving 15,000 km a year will save 60 liters of diesel or as Nordström put it, one fuel tank.

Volvo did not disclose any performance figures for the updated 2010MY S80 and V70 DRIVe, but just to get an idea, the 2009MY S80 DRIVe accelerates from standstill to 100km/h in a claimed 12.4 seconds and reaches a top speed of 118mph or 189 km/h.

We say that, while any efforts to improve CO2 emissions and fuel consumption are more than welcome, fitting a puny 1.6-liter diesel engine in cars of the size and weight of the S80 and V70, isn't exactly pioneering anything new...