PRESS info P07901EN / Per-Erik Nordström 5 September 2007 Technological breakthrough for Scania: Euro 5 without aftertreatment or fuel penalty As the first heavy vehicle manufacturer, Scania achieves Euro 5 without exhaust aftertreatment, thus maximising user convenience. Several new technologies, including a new fuel injection system, are employed to secure performance and fuel efficiency. Two of the new engines intended for urban applications also comply with EEV. After five years development at the Scania Technical Centre in Södertälje, Sweden, Scania's new Euro 5 engine platform is ready for the market, starting with the 5- and 6-cylinder inline engines. It will gradually replace the current platform over the next few years. Euro 5 becomes mandatory within the European Union in October 2009. From the outset the new engine platform has been optimised for EGR, exhaust gas recirculation, and for Scania XPI, the new injection system developed jointly with Cummins. This decision was steered by demands and targets for performance and fuel economy, as well as for consistent environmental performance, robustness and convenient operation. With EGR, emissions are lowered already during combustion, eliminating the need for aftertreatment equipment and tanks to carry additives onboard the vehicle. Scania has secured control of all strategic steps in engine development and performance control: basic engine development and manufacturing, engine management, fuel injection and emission control. Scania Euro 5 and EEV inline engines with EGR Power 230 hp 270 hp* 280 hp 320 hp 360 hp 400 hp 440 hp 480 hp Torque 1050 Nm 1200 Nm 1400 Nm 1600 Nm 1900 Nm 2100 Nm 2300 Nm 2500 Nm Swept volume 9.3 8.9 9.3 9.3 Bore 130 mm 127 mm 130 mm 130 mm 130 mm 130 mm 130 mm 130 mm Stroke 140 mm 140 mm 140 mm 140 mm 160 mm 160 mm 160 mm 160 mm Emissions Euro 5 Euro 5 Euro 5 and EEV and EEV and EEV Euro 5 Euro 5 Euro 5 Euro 5 Euro 5 * Ethanol engine. See separate releases about engine range and technical data. Scania Corporate Relations Telephone +46-8 5538 1000 S-151 87 Södertälje Telefax +46-8 5538 5559 Sweden www.scania.com
2 (6) More performance, no fuel penalty In terms of fuel economy, the new engine range has been developed to fully match Scania's range of Euro 3 and Euro 4 engines. 6.0 5.0 Torque/power ratio The high torque delivery at low revs opens the possibility to save additional fuel by specifying a faster rear axle ratio. Nm/hp 4.0 3.0 2.0 All engines have been tuned to give maximum torque from 1000 r/min for extra low-speed power and driveability. Maximum torque extends to 1350 r/min (230 hp: 1000-1500 r/min) for 9-litre and to 1300 r/min for 13-litre engines. 1.0 0.0 Competitors Scania Euro 5 EGR The average torque-to-power ratio (Nm/hp) in the 300-500 hp range of 5- and 6- cylinder engines (Euro 4 and 5) is higher than for competitors (see figure). The ratio for each of the new Scania EGR engines is higher than for any competitor in this output range. Extended maintenance intervals Oil-change intervals for the new engine platform have been extended. This has a positive effect on uptime and scheduled servicing. Engine oil-change intervals are now: Up to 120,000 km at max. 36 tonnes gross weight. Up to 90,000 km at max. 45 tonnes gross weight. Like previous Scania engines, the new engine platform is modularised with shared components and systems between the different series. This facilitates servicing, staff training and parts supply. New features Oil level indication in the instrument cluster permits checking of the oil level from the driver s seat. The level cannot be checked with the engine running. After stopping, an estimated time is displayed indicating when the level can be measured again after the oil has run back into the sump. The difference between max./min. marks is 5 for 9-litre and 8 for 13-litre engines. Adaptive battery charging adjusts the charge voltage from the alternator according to the battery temperature. The voltage increases at low temperature and decreases at high temperature, resulting in faster charging of cold batteries and more gentle charging of warm batteries. Scania is the first heavy vehicle manufacturer to implement this feature. More powerful 100 A alternator is standard, with a 150 A heavy-duty option. Emission performance All new engines are certified to comply with Euro 5. Two 9-litre engines, 230 and 280 hp, are also certified according to EEV, the strictest certifiable emission level today. See separate release about the engine range.
3 (6) The 230 and 280 hp engines are fitted with a maintenance-free part-flow particulate filter to give low emissions of all regulated substances. The other engines manage Euro 5 without aftertreatment. This includes the new ethanol version. In-house engine management system To secure control of all aspects of engine performance, Scania has developed a new generation of engine management systems. The multitude of functions controlled include fuel injection, dual-stage EGR, charge-air, cooling fan and engine operating temperature, variable-geometry turbo, exhaust braking, emission compliance (NOx control), exhaust aftertreatment and engine oil level. The control unit is mounted on the cool side of the engine. On 6-cylinder engines, the unit is cooled by the flow of fuel from the tank to the low-pressure pump; 5- cylinder engines do not require more cooling than that provided by the airflow when driving. The new engine management system also provides advanced on-board diagnostics that will be further developed over time and allows detailed logging of operational data for subsequent analysis. Together with the new Scania Communicator, logging can be done remotely via the Scania Fleet Management portal. Analyses can be performed on driver as well as vehicle data. Engine architecture The new engine platform is a completely new design, yet it retains traditional Scania traits like separate cylinder heads, camshaft located high in the block and rearmounted timing gears, as well as the familiar cyclone oil filter. Bore (9- and 13-litre) and stroke (13-litre) have been slightly altered and swept volume increased compared to current engines. The cylinder block and other structural components have been redesigned for additional strength without the need for special grades of steel. A ladder frame is incorporated in the sump of 6-cylinder engines to counteract noise and vibration. This function is fulfilled by twin balance shafts on 5-cylinder 9-litre engines. Common-rail fuel injection The new common-rail fuel injection system, Scania XPI (extra high-pressure injection), has been developed jointly with Cummins. Scania has co-operated with Cummins to develop injection and combustion technology since the early 1990s. Scania HPI, launched in 2001, was the first result of this long-term strategic alliance. Development has centred on achieving higher injection pressure than customary for this type of system. High injection pressure reduces the formation of particulate matter (PM) already during combustion, eliminating the need for aftertreatment to reach Euro 5. The new system allows a high degree of freedom in terms of injection timing and pressure. With common-rail, injection timing and duration are independent of the camshaft. High injection pressures are available at any time, irrespective of engine speed. It also opens the possibility to use several injection pulses, see below.
4 (6) Control of the fuel injection system is all-electronic. This means that there are no lobes on the camshaft to actuate the fuel injectors, nor are there any tappets, pushrods or rocker arms for this purpose. Fuel under high pressure is constantly available in the rail, giving the possibility of injecting fuel at any time, independent of camshaft position. Scania XPI schematic 1. Low-pressure pump 2. Fuel filters with water separator 3. Inlet metering valve 4. High-pressure pump 5. Rail (accumulator) 6. Rail pressure sensor 7. Mechanical dump valve 8. Return rail 9. Electronically controlled fuel injector Working principle of Scania XPI Fuel is sucked from the tank by the low-pressure pump via a prefilter with a water separator via the cooling circuit for the engine management system to the main fuel filters. Water in the fuel is automatically drained back to the tank via a venturi device. The low-pressure pump supplies fuel via the inlet metering valve to the highpressure fuel pump. The pumps, which are integrated into one unit together with the fuel metering valve, are driven by the timing gears of the engine. The high-pressure pump supplies fuel under operating pressure to the rail, i.e. the accumulator running the length of the engine on the cool side. The operating pressure is regulated by the amount of fuel admitted by the inlet metering valve, ranging from an idling pressure of around 500 bar to a peak pressure of 2400 bar. The average working pressure is around 1800 bar. The inlet metering valve is controlled electronically by the engine management system via a closed loop from a pressure sensor in the rail. A mechanical dump valve on the rail prevents excess pressure build-up by sending fuel back to the tank via the return rail. The fuel injector for each cylinder is constantly fed with high-pressure fuel from the rail. Injection pulses are controlled electronically via a servo valve in the injector. The injector remains open as long as current is supplied from the ECU. The amount of fuel injected depends on the opening time and the pressure in the rail. The starting time of the pulse determines the start of injection. Fuel is injected into the combustion chamber through the injector nozzle.
5 (6) Multiple injections Multiple injections are possible with this electronically controlled injection system. A small amount of fuel (pilot injection) can be injected slightly before the main injection to reduce noise and prepare the combustion chamber for lower emissions. Pilot injection Main injection Post injection A small post-injection shortly after the main injection reduces soot and NOx. It can also be used to control exhaust temperature to suit some future aftertreatment systems. Two-stage EGR-cooling, exhaust gas recirculation Continued use of EGR also for Euro 5 means that customers can continue to operate without the need for additives. Scania EGR has been revised to provide higher efficiency and capacity. Scania EGR with two-stage cooling Stage 1: water-cooled EGR-cooler along the block Stage 2: air-cooled EGR-cooler on top of the charge-cooler Mixing cooled exhaust gases with the intake air reduces the oxygen content. This has the effect of lowering the combustion temperature, which in turn reduces the formation of nitrogen oxides, NOx, already during combustion. A high-capacity water-cooled EGR-cooler is mounted on the engine. Recirculated exhaust gases are supplied from the exhaust manifold, cooled and passed on either to the intake side or to a second cooling stage. The amount of EGR admitted to the intake is regulated electronically via an EGR valve and by varying the geometry of the turbocharger, thus varying the exhaust backpressure. On high-output engines, two-stage EGR-cooling is employed to secure the flow and temperature according to the needs of the engine. The second stage consists of an
6 (6) air-cooled radiator mounted on top of the charge-cooler. A by-pass valve regulates the flow through the second EGR cooler. Some features in this new two-stage EGR system have been patented by Scania. Scania VGT (variable-geometry turbocharger) 1. Air intake 2. Compressor wheel 3. Charge air outlet 4. Speed sensor 5. Actuator 6. Sliding nozzle-ring 7. Turbine wheel 8. Exhaust gas inlet 9. Exhaust gas outlet Variable-geometry turbocharger, VGT The geometry and gas flow in the variable-geometry turbocharger is regulated by the sliding nozzle-ring, which is controlled by an electric actuator. This allows precise control of both charge-air to the engine and the flow of EGR. The flow of intake air can be optimised throughout the working rev range of the engine. This means that the VGT can be used to improve engine response and lowspeed torque. It is also used to speed up gearchanges with Scania Opticruise by maintaining the turbine speed during gearchanges. Other powertrain news Brake blending is used to complement the Scania Retarder during gearchanges going downhill. This means that the service brakes are applied briefly to compensate for the loss of engine braking until the next gear has engaged, thus maintaining a constant speed. 11-blade fan optional for V8 vehicles operating in very hot climate. Triple monitoring functions to further extend clutch life: overload warning, wear protection and slip detection. * * * For further information, please contact Per-Erik Nordström, Product Affairs, tel. +46 70 5535577, email per-erik.nordstrom@scania.com