A NEW diesel engine has been developed by Volvo and it has the potential to make the Swedish car firm's large cars as economical as a family hatch.
The four cylinder, two-litre diesel is the first of a family of Drive-E engines which by 2017 will be powering the entire Volvo line up.
With a variety of power outputs ranging from 120 to 300bhp the new technology will become the bedrock of all Volvo engines, both petrol and diesel.
It is being introduced in diesel form on all but the V40 hatch and the larger XC90 SUV and in the case of the S60 saloons and V60 estates it makes them the most economical medium sized executive cars on the market.
Volvo claims the new S60 and V60 D4 models can achieve 74.3mpg with class leading emissions of 99g/km.
For company car drivers the savings are significant and add up to a reduction in monthly tax bills of almost 40 per cent when compared to the likes of a BMW 320d SE which has a CO2 figure of 120g/km.
The new Volvo can also out-perform its German rival and despite its eco credentials has a sub-seven second 0 to 60 time and a top speed of 143mph.
On the road the new engine has considerable muscle and with a six speed manual gearbox the new S60 has become a genuine sports saloon.
The previous D4 engine mustered 161bhp, the new one has 181bhp yet despite being quicker its official fuel consumption has improved by almost 10mpg and the emissions are down by 20g/km.
In mid-range SE Nav trim it's priced from £29,395, an increase of £250 over the previous D4 model and a difference which will take only a few tanks of fuel to cancel out.
The power of the new engine is obvious at the touch of the accelerator. It is lively and feels potent but sounds smooth and refined.
The car we tried was six speed manual and mid-range pull is very impressive. Across the Peak District there are plenty of steep conditions to test a car to the full yet even so the S60 managed to return an average close on 55mpg.
Of the new breed of super-efficient diesel engines this is one of the best and even in the larger V70 and XC70 estates it was not overtly thirsty.
Volvo claims fuel returns of in the low to mid-60s for both although on the XC70 the new engine is only available in front-wheel-drive form at the moment. We saw mid-40s over similar routes.
One of the secrets of the new engine is a high pressure injection system developed in conjunction with Japanese automotive specialist Denso which controls the fuel burn for optimum power and economy.
It's impressive equipment which at the moment is top of the class.
The Drive-E project began while Volvo was under Ford ownership back in 2007 and was only given the green light in 2011 after the company had been sold to Chinese car makers Geely.
All the new Drive-E engines have been designed to integrate hybrid electronics on future models and in the case of the petrol engines Volvo says the four cylinder blocks will out-perform current V6 and even some V8s while being up to 35 per cent more fuel efficient.
For Volvo this is gamechanging technology which not only transforms its current big car line up but gives it one of the best diesels around.