Volvo unveils new five-pot diesel

Anxious not to get left behind by its German rivals in the diesel race, Volvo has unveiled a new five-cylinder oiler that's due to debut in its S80 flagship sedan.

Although the 2.4-litre engine wears the 'D5' designation, it's not to be confused with the similarly badged unit that's currently offered here in the S80 (and C30, S40 and V50).

Whereas the existing S80's D5 unit ekes out 136kW and 400Nm, the new-gen powerplant puts out 151kW and 420Nm.

Due to debut here in the second half of 2009, the new D5 features sequential twin turbochargers, ceramic glow plugs and piezoelectric fuel injectors.

At lower rev ranges, the smaller turbocharger ensures rapid acceleration without any perceptible lag, says Volvo, while at higher ranges, the larger turbocharger delivers the high levels of power and torque not available with a single unit.

Volvo claims this power means there are always ample resources for quick overtaking, particularly between 80 and 120km/h.

The company also boasts of a refined engine note that supposedly bears "a closer resemblance to the noise of a six-cylinder petrol engine".

Volvo claims its boffins have cut fuel consumption to class-leading levels for a car of the S80's size, and the company quotes a consumption figure of 6.2 litres/100km and CO2 emissions of only 164g/km.

In addition to piezoelectric fuel injectors and improved EGR control, the new D5 engine uses ceramic glow plugs, said to deliver excellent cold-starting properties thanks to a quick warm-up period.

They reach a temperature of 1000 degrees Celsius in just two seconds, making the engine easy to start and thus cutting emissions, claims Volvo.

"Our brief was to develop a modern performance diesel engine that meets the Euro 5 standard," says Volvo's boss of Powertrain Engineering, Derek Crabb.

"The previous engine has undergone constant development but has now reached the end of its potential. We therefore decided to start with a clean sheet of paper and harness the advanced technology that we have access to today."