7 September 2005

During the Scania EuroDrive 2005 event, Scania has unveiled a new line-up of Euro IV and Euro V heavy-duty truck engines. The Euro IV emission standards (NOx = 3.5 g/kWh, PM = 0.02 g/kWh) become effective from October 2005 for new type approvals, and from October 2006 for new registrations of vehicles with previously type-approved engines. The respective dates for Euro V standards (NOx = 2.0 g/kWh) are October 2008 and October 2009, but early introduction of compliant engines is encouraged by incentive programs.

The preferred NOx emission control technology is cooled exhaust gas recirculation (EGR), as it was the case in the bus engine strategy unveiled in June. The use of selective catalytic reduction with urea (urea-SCR) is limited to larger engines, which may be facing more challenging EGR heat release problems.

The following is a summary of the emission technologies on the new engine line-up. The Euro IV engines will be available this fall, the first Euro V engines will be available in 2006.

  • Euro IV engines:
    • Cooled EGR: 9-liter (230, 270, 310 hp) and 12-liter (340, 380, 420, 470 hp)
    • Urea-SCR: 16-liter (500, 560, 620 hp)
  • Euro V engines:
    • Cooled EGR: 9-liter (270 hp)
    • Urea-SCR: 12-liter (420 hp) and 16-liter (500 hp)

Future development is focused on implementing of EGR, in conjunction with the new XPI injection system, on increasing number of Euro V models. In the longer term, Scania is also considering the use of HCCI combustion engines.

The EGR rates are up to 18% in Euro IV engines, and up to 25% in Euro V engines. In non-turbocompounded engines—up to 380 hp—the EGR flow is driven by a venturi installed in the intake manifold. The venturi has two positions to accommodate different EGR flow requirements at different engine conditions. No venturi is needed in engines with turbocompounding—420 and 470 hp—as the exhaust manifold pressure is higher due to the additional turbine. An oxidation catalyst, integrated into the silencer, is used on EGR-based engines for the control of PM and the diesel smell.

Reduced engine weight is one of the advantages of EGR, compared to urea-SCR, according to Scania. The weight increase with Scania EGR and venturi is around 20 kg, and the weight of the turbocompounding unit and EGR system is around 80 kg, compared to around 200 kg for SCR-based systems, said Scania.

Fuel economy and operating costs of the new Euro IV engines are similar to those in existing Euro III engines, said Scania.

Source: Scania (EuroDrive press kit)