MAN's Frankfurt launches will be greener and safer
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• by Toby Clark When MAN revealed its new line-up of TO-A trucks—the revised M2000 and L2000 ranges and its Euro-3 engines (CM 27 July-2 August)—it also showed some developments it will feature at the IAA Show in Frankfurt next month. Several of these will be combined in the TO-X concept vehicle, a superstreamlined, ultra-economical development of the TO-A with experimental wheels and tyres and a catalysed engine.
Design philosophy
MAN has also described its engine design philosophy for the Euro-4 and Euro-5 emissions legislation.
The firm recognises that there are two main approaches to the key problems of particulates and nitrogen oxides (NOx).
The first of these is to reduce NOx formation within the combustion chamber, then trap particulates using a secondary filter or continuously regenerating trap (CRT). MAN considers that this will be practical for Euro-4 in 2005, but that it will result in unacceptable fuel consumption penalties beyond Euro-4.
The second approach minimises particulates inside the engine, followed by catalytic after-treatment to reduce NOx emissions. This is possible using the SlN0x urea catalyst system, but Euro-5 limits (from 2008) are likely to need an additional oxidation catalyst to improve the efficiency of the SINOx reaction. MAN is already demonstrating both approaches to emissions, and both versions are planned to make it into production.
Injection technology
MAN's current medium-duty four and sixcylinder DOB engines all use conventional injection technology. The Euro-3 versions (described last week) combine the Bosch VP44 electronically controlled distributor pump with an internal exhaust gas recirculation (EGR) system.
Sophisticated engine management and (on the most powerful versions) a turbocharger wastegate control emissions while maintaining driveability. The heavyduty, six-cylinder D28 engines use a controlslide injection pump and externally cooled EGR in Euro-3 form, while the latest 510hp version adds a wastegate.
The next generation of engines will use common-rail injection (as already offered by Renault in its dCi engine) which will be unveiled in a flagship 700hp VICI Euro-3 engine in prototype form at the IAA Show.
The D2840 LFV10 will be rated at a maximum of 1,990Ibft (2,700Nm) from 1,000-1,700rpm, and uses one turbocharger and one high-pressure fuel rail for each bank of
four-valve cylinders. The fuel is
pressurised to 1,400 bar by a Bosch in-line piston pump, and the system is said to offer several advantages, including: • Injection timing is totally independent of engine speed; • High injection pressure, even at low engine speed; • Multiple injection stages (including pm and post-injection); and
III Efficiency gains from the constantly pressurised fuel pump.
The other innovation in the V10 is its version of EGR, in which the intake pipes of both banks of cylinders are constantly fed from a single cylinder, giving a consistent recirculation rate of 10% throughout the load and rev range.