Volvo Introduces Two New 5-Cylinder Diesels; More Power, Less Fuel Consumption

17 February 2009

The single-turbo 2.4D. Click to enlarge.

Volvo Cars is introducing two entirely new five-cylinder, 2.4-liter turbo diesels: the high-performance, twin-turbo D5 with 205 hp (153 kW) and 420 Nm (310 lb-ft) of torque, and the medium-performance, single-turbo 2.4D with 175 hp (130 kW) and 420 Nm of torque.

The high-performance D5-engine has already been introduced in the Volvo S80. (Earlier post.) Both engines will be available in the Volvo S80, Volvo V70, Volvo XC60 and Volvo XC70 in select markets from the spring of 2009.

The twin turbo system. Click to enlarge.

The twin turbochargers are of different sizes and together deliver boost pressure of 180 kPa (1.8 bar), across a broad rev range. The smaller turbocharger is used primarily at lower revs. It reacts more alertly than the larger one and provides immediate response to quick throttle movements. At higher revs, the larger turbocharger takes over to provide more propulsion when accelerating at higher speeds.

This twin-turbo technology in the D5 has also made it possible to introduce higher levels of exhaust gas recirculation (EGR) across a wider rev range than before. This harnesses the two turbochargers’ different properties optimally to deliver a combination of high performance and low fuel consumption.

The fuel injection system uses piezoelectric fuel injectors, enabling precise distribution of the atomized fuel in the combustion chamber, resulting in efficient combustion and low emissions. At the same time, this technology and the efficient combustion create a sound bearing a closer resemblance to that of a six-cylinder gasoline engine.

Fuel consumption figures (EU combined) with CO₂ emissions for the D5 are:

• 6.2 L/100km (38 mpg US); 164 g/km in the S80
• 6.4 L/100km (37 mpg US); 169 g/km in the V70
• 7.0 L/100km (34 mpg US); 185 g/km in the XC60 (preliminary)
• 7.0 L/100km (34 mpg US); 185 g/km in the XC70 (preliminary)

The single-turbo 2.4D has been optimized for lower fuel consumption. The injection system features another type of piezoelectric fuel injectors than used in the D5, aiming to cut fuel consumption through extremely rapid and precise injection sequences. The high injection pressure results in effective combustion.

To promote the drivability, the single turbocharger has been optimized to produce high torque from low revs. The upgraded single-turbo 2.4D-engine gives a fuel consumption (EU Combined) of:

• 5.8 L/100km (41 mpg US); 154 g/km in the S80 (preliminary)
• 5.9 L/100km (40 mpg US); 157 g/km in the V70 (preliminary)
• 6.0 L/100km (39 mpg US); 159 g/km in the XC60
• 6.0 L/100km (39 mpg US); 159 g/km in the XC70

The two new diesel engines share a number of technology solutions. The engines have lower compression, more efficient combustion and the latest generation of engine management. Volvo engineers have reduced internal friction and pump losses in the diesel engines. The pressure drop in the intake and exhaust system has also been significantly reduced.

The new turbo diesels have also been equipped with ceramic glow plugs, which deliver excellent starting properties owing to very quick warming up. They reach a temperature of 1,000 °C in just two seconds, making the engine easy to start and cutting emissions. In certain driving conditions, such as at really low revs, the ceramic glow-plugs can also be used to increase the temperature in the cylinders, further improving combustion efficiency.