Scania Introducing New Euro 5 Engine Platform
05 September 2007
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| Cutaway of the new Scania Euro-5, 5-cylinder, 9-liter engine. Click to enlarge. |
Scania is introducing its new Euro-5 compliant engine platform, starting with the 5- and 6-cylinder inline engines. The new platform will gradually replace the current platform over the next few years—Euro 5 becomes mandatory in October 2009.
Scania is achieving Euro 5 without exhaust gas aftertreatment, and three of the new engines—including a new ethanol engine—comply with EEV. The EEV concept (enhanced environmentally friendly vehicle) was introduced by the EU in 1999 to promote the use of the best available environmental technology for sensitive environments. EEV limits were then only attainable with natural gas engines. When Euro 5 was decided a few years later, the limits were set fairly close to EEV, although EEV is still tougher than Euro 5 on hydrocarbons.
| EU Emissions Standard for Heavy-Duty Diesel Engines (g/kWh) | ||||
|---|---|---|---|---|
| Standard | CO | HC | NOx | PM |
| Euro 3 (2001) | 2.1 | 0.66 | 5.0 | 0.10 |
| Euro 4 (2006) | 1.5 | 0.46 | 3.5 | 0.02 |
| Euro 5 (2009) | 1.5 | 0.46 | 2.0 | 0.02 |
| EEV (decided in 1999) | 1.5 | 0.25 | 2.0 | 0.02 |
This capability is the result of a number of new technologies, including a new fuel injection system, which Scania uses to control performance and fuel efficiency. Scania is also premiering its third-generation ethanol engines, and is advancing the testing of its hybrid technology (earlier post).
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| The Scania XPI system. Click to enlarge. |
The new engine platform is optimized for exhaust gas recirculation (EGR) and for Scania XPI, the new extra high-pressure injection system (peak pressure of 2,400 bar, average working pressure of around 1,800 bar) developed jointly with Cummins.
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. 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.
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.
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| Scania two-stage EGR system. Click to enlarge. |
Scania revised its EGR to provide higher efficiency and capacity. 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.
High-output engines use two-stage EGR-cooling. The second stage consists of an 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.
The new engine range has been developed to fully match the fuel economy of Scania’s range of Euro 3 and Euro 4 engines. All engines have been tuned to give maximum torque from 1000 rpm for extra low-speed power and driveability. Maximum torque extends to 1350 rpm for 9-liter and to 1300 rpm for 13-liter engines.
The high torque delivery at low revs enables additional fuel savings by specifying a faster rear axle ratio.
Scania developed a new generation of engine management systems to control of all aspects of engine performance: 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 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.
Ethanol. Scania recently launched its third-generation ethanol engine, certified for both Euro 5 and EEV. At 43%, the thermal efficiency of Scania’s new ethanol engine is on a par with its diesel engines (44% thermal efficiency). The fuel use for diesel combustion is ethanol mixed with 5% ignition improver.
Biodiesel. Scania supports the use of up to 100% biodiesel in its modern engines under certain conditions. Oil-change intervals are halved and the vehicles must be continuously monitored in operation if the mix exceeds 5%. Biodiesel fuel must comply with European fuel standard EN14214,
While engine efficiency is high since the engine operates according to the diesel principle, power is down by 17%. NOx is up by 17%, according to Scania, but particulates are down substantially and fossil CO2 is reduced by up to 70%.
Synthetic diesel. Scania is participating in a 3-year large-scale trial with bio-based synthetic diesel, that, according to the company, looks very promising.
Posted by: Dr.win lei lei phyu | 14 November 2007 at 10:18 PM