The D13A is 20 kg lighter than its 12-liter predecessor, the D12D, but is also more powerful and efficient.

An increased stroke length delivers greater cylinder volume and higher torque. The result is faster acceleration, better driveability with fewer gear changes and lower diesel consumption than the D12D (up to 5%). The engine is also more powerful, allowing a higher average speed and more cost-effective driving.

Both the D13A and the D9B have their timing gears at the rear of the engine, making it possible to extract higher torque for power take-off. The D13A offers up to 900 Nm torque at standstill.

The D13A is the first Volvo engine that supports closed crankcase ventilation (CCV). The gases from the cylinder head cover are recirculated to the turbo unit via an oil separator with a centrifuge, keeping the engine clean and leak-free. The centrifuge system requires no maintenance whatsoever. CCV is available on the D9B as an option.

The D13A is available in four power levels: 400 hp (294 kW), 440 hp (324 kW), 480 hp (353 kW) and 520 hp (382 kW) (only for the Volvo FH).

Volvo upgraded its D9 engine to provide greater power and torque across a wider range of revs. The D9B is available in three power levels: 300 hp (220 kW), 340 hp (250 kW) and 380 hp (280 kW).

Selective Catalytic Reduction (SCR) is Volvo’s designated technology for achieving Euro 4 and Euro 5 compliance. (Compare Scania’s EGR approach here.)

The basic versions of the D13A and D9B meet Euro 3 emission standards. Exhaust gas aftertreatment with AdBlue and SCR catalyst cleaning allow both Euro 4 and Euro 5 standards to be met.

The main difference between the solutions for the two standards is the proportion of AdBlue to fuel: 3-4% AdBlue is required for Euro 4 compared to 5-7% for Euro 5.

Selective Catalytic Reduction

An SCR system injects urea (AdBlue) into the hot exhaust gas where the urea decomposes into ammonia (NH₃). NO_x reacts with NH₃ on the surface of the catalyst to produce nitrogen (N₂) and water vapour (H₂O).

Volvo also offers EGR (Exhaust Gas Recirculation) options. All Volvo trucks manufactured in the US as of 2002 are equipped with the EGR system, and Volvo will be offering EGR-equipped trucks in Europe during the second quarter of 2006. But SCR is the company’s main NO_x reduction technology.

We see SCR as by far the best choice for meeting Euro 4. Furthermore, according to our evaluations, it is the only alternative that directly meets Euro 5 standards. We believe that it may be wise to choose Euro 5 already since this is the solution most highly recommended by the authorities and it saves having to upgrade the system later.

—Roar Isaksen, President Europe Division

(As a side note, even Scania, with its strategic focus on EGR, uses SCR in its newly introduced Euro 5 high-power engines. The company is working on EGR solutions for engines with that level of performance.)