Scania Euro 6 – first engines ready for the market.
Scania is unveiling 440 and 480 hp 13-litre Euro 6 engines mainly intended for long-haulage, but also suitable for other types of applications. This will open the possibility for operators to invest in the latest emission technology. The engines combine a host of innovative technical solutions to cut emissions radically, while the consumption of fuel is as good as Scania's Euro 5 engines.
Martin Lundstedt, Executive Vice President in charge of sales and marketing:
“We are proud to be able to make this remarkable feat of engineering available to our customers now. The new engines are designed to give the same performance and fuel efficiency as their Euro 5 counterparts.
“These engines make it possible for keen operators to take the next step and invest in the greenest technology available in the market. They will be able to benefit from lower motorway charges and other incentives that may be introduced by authorities. Vehicles with the latest emission standard also command a higher value in the second-hand market.”
Euro 6 is a drastic downward step in emission levels compared to Euro 5. Emissions of nitrogen oxides and particulates are around one-fifth of those for Euro 5 engines. A new element in emission testing is that the particles also need to be counted, which in practice means that the actual particulate emissions will be around one-sixth of Euro 5.
Jonas Hofstedt, Senior Vice President Powertrain Development:
“All the development work has been performed in-house at Scania. We have combined all the new technologies that Scania has developed in recent years: exhaust gas recirculation, variable turbo geometry, common-rail high-pressure fuel injection, selective catalytic reduction and particulate filtering. Add to that our own engine and exhaust management technology, which has now been integrated into one system.
“We have spared no effort to avoid fuel penalties on these engines. Operators will find that fuel economy, driveability and engine response are fully on a par with our Euro 5 engines,” concludes Mr Hofstedt.
Euro 6 emission standards will enter into force in the European Union and certain neighbouring countries on 31 December 2012 for new vehicle models and one year later for all new vehicles sold.
The following emission levels apply.
• Nitrogen oxides: 0.4 g/kWh (2 g/kWh for Euro 5).
• Particulate matter: 0.01 g/kWh (0.02/0.03 depending on test cycle for Euro 5).
• Particulate count: 6.00 x 1011 particles/kWh (transient test cycle). 8.00 x 1011 particles/kWh (stationary test cycle). This amounts to 600 or 800 billion particles per kWh. One kWh corresponds to the energy consumed during approx. 30 s of driving for a 40-tonne combination at highway speed. There is no counting requirement for Euro 5, but the reduction in the number of particulates is likely to be around 99%.
Euro 6 is the first step towards the implementation of world harmonised emission standards, encompassing Europe, North America and Japan, and this will facilitate coordination and development for future standards. The Euro 6 levels are close to those applying in North America (EPA10) and Japan (Post NLT) starting in 2010. Euro 6 is the first time the new WHDC (world harmonised duty cycle) is stipulated for certification.
Performance up to Euro 5 standards in all respects
The new engines have been developed to correspond precisely to the high performance and characteristics expected by Scania customers. Performance is very similar to the Euro 5 EGR engines on which they are based, hence the torque-to-power ratio is around 5.2, which is the highest in the industry.
As on Scania's other Euro 5 engines, full torque is available already from 1,000 r/min, giving excellent driveability and the ability to specify vehicles for low-rev cruising at 1,100 r/min or even lower to optimise fuel economy. Transmissions include 12+2-speed range-splitter gearboxes with or without overdrive. Scania Opticruise is recommended to ensure maximum fuel efficiency and to facilitate gearchanging (also available with clutch pedal). Manual gearchanging can be specified. Scania Retarder is an option in all combinations.
Scania's extensive testing and customer trials have shown that the performance objectives have been achieved to the full and that there is no noticeable difference in the amount of fuel used. The consumption of AdBlue corresponds to 3-4% of the fuel consumption, compared to 5-6% for Scania's Euro 5 SCR engines.
Scania Euro 6 engines are currently approved for running on typical mixes of up to 8% approved biodiesel in normal diesel. Tests are ongoing to secure the long-term functioning of the aftertreatment system when running on up to 100% biodiesel.
The new 440 and 480 hp engines are based on Scania's latest modular engine platform with 130 mm cylinder bore introduced as Euro 5 with EGR in 2007. These engines feature common-rail fuel injection (Scania XPI), EGR and variable-geometry turbocharging (VGT). The first V8 engine on this platform (730 hp, 3500 Nm) was launched in 2010, also equipped with Scania XPI and VGT, but with SCR exhaust aftertreatment like the other Euro 5 V8 engines.
Scania’s own engine management system is used on the entire range. The fully modular design means that many parts and components are shared across the range, which facilitates servicing and promotes parts availability.
The cast-iron cylinder block is unchanged, being designed from the outset for high combustion pressures (in this case up to 200 bar). As on Scania's other 13-litre engines, a ladder frame between the block and the sump is used to stabilise the lower part of the engine and counteract noise and vibration. Low-friction plasma-coated cylinder liners are used to reduce fuel consumption. Steel pistons are used with a slightly reshaped bowl giving a 17.3:1 compression ratio.
Low-emitting open crankcase ventilation is standard and the new plastic oil sump increases oil capacity by 3 litres, while reducing noise and saving weight. The weight of the engine itself is similar to Euro 5 EGR. Overall vehicle weight is up by up to 200 kg due to the AdBlue system (75-litre tank) and the added complexity of the exhaust system.
Cooling capacity was upgraded for the needs of Euro 6 in conjunction with the launch of the new R-series in 2009. A smart cooling fan is used that interacts with the engine management system to save fuel and to optimise retarder performance. A high-speed cooling fan can be specified for exceptional conditions.
Engine management – including full aftertreatment control
The new Scania Engine Management system (same as on the 16.4-litre V8) controls all engine parameters as well as the exhaust aftertreatment system, without compro-mises on either and with full integration with other systems on the vehicle. An innovative solution with sensors in the silencer ensures precise control of exhaust temperature and NOx levels.
The Scania XPI (extra high pressure injection) common-rail fuel injection system is designed for injection pressures of up to 2,400 bar, with typically around 1,800 bar in normal operation. The eight-hole injectors provide up to three injection pulses per cycle to achieve optimum engine and emission performance.
When needed, post injection is used to maintain the optimum exhaust temperature for good SCR function and also to assist the regeneration of the particulate filter.
Intake air handling
Scania VGT (variable-geometry turbocharging) is combined with Scania EGR (exhaust gas recirculation) with single-stage cooling. VGT significantly boosts driveability and engine response and is also beneficial for the gearchanging speed with Scania Opticruise. EGR rates are somewhat lower than for Euro 5 (up to 25% vs. 30%) since the EGR and SCR systems can be balanced for optimum performance.
An intake air throttle with position sensor is used to finely control intake airflow. Restricting the flow through the engine when it is not pulling helps keeping up the temperature in the exhaust system to achieve maximum efficiency in the SCR system.
The integrated silencer is an exceptionally compact insulated unit containing an oxidation catalyst and a full-flow particulate filter, followed by two parallel SCR catalysts and ammonium slip catalysts.
Scania has developed a new electrically actuated AdBlue dosage system for higher precision, greater robustness and airless operation. AdBlue is injected into a mixer (patented by Scania) and evaporates into urea before entering the two parallel SCR catalysts.
Next in line is a compact and efficient ammonium-slip catalyst to remove any ammonium left in the exhaust flow. The evaporation route is extremely short, making it easy to maintain the required temperature. The system is monitored by new temperature, pressure and NOx sensors for optimum performance and control.
The EGR and SCR processes are continuously balanced to optimise emission performance. Typically, around 50% of NOx emissions are eliminated at source by the EGR system and another 95% in the SCR catalysts and the particulate filter reduces particulate emissions by 99%.
Integrated particulate filter
Via two sensors, the pressure differential is monitored across the integrated particulate filter to assess the degree of contamination and, hence, the need for regeneration. Regeneration takes place continuously during driving. If the filter still starts to clog with soot, the driver will get recommendations in the central instrument (see table). A switch is provided in case a stationary regeneration cycle should be required.
The particulate filter needs to be cleaned at regular intervals (see Maintenance requirements). It is detachable from the silencer unit, which is mounted on a swing-out attachment with two bolts for easy maintenance and replacement of the filter cartridge.
Maintenance intervals are the same as for Scania's 13-litre Euro 5 EGR engines, i.e. up to 90,000 km (120,000 km at max. 36 tonnes GVW), depending on application.
This requires the use of Scania LDF-3 long-drain lubrication oil, which has been specifically developed for Euro 6 engines and engines with particulate filters. The intervals for changing the particulate filter are dependent on the type of operation, but will typically be around 240,000 km in long-haulage. Scania recommends the use of Scania Service Exchange filters to minimise the time required in the workshop.
Chassis installation same as for Euro 5
The compact design of the silencer unit means that it does not take up more space on the frame than the Euro 5 design (EGR or SCR). The modular design makes it readily adaptable to suit different bodywork installations. The position of the outlet pipe has been chosen to enable customers at a later stage to specify a vertical exhaust system (exhaust stack) for example on eight-wheelers.
The same fuel tank alternatives are available as for Scania's Euro 5 SCR engines, with a choice of 50 or 75-litre AdBlue tanks. With rear-mounted batteries, up to 1,500 litres of fuel capacity can be specified on a 4x2 tractor unit, with standard batteries up to 1,370 litres.