Volvo uprates low-speed torque
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VOLVO has replaced the TD 120A engine in its bonnetted N12 construction vehicle with the latest TI) 120E version. The engine has had several improvements and now yields 30 per cent more torque between 1,000 and 1,300rpm.
Maximum power of the Erated version of Volvo's familiar 12-litre (732cuin) turbocharged unit is 225kW (306bhp) at 2,200rpm and the maximum torque is 1,220Nm (890lbft) at 1,300rpm. The maximum torque figure is practically unchanged, but what Volvo has done is to eliminate the rather drastic fall-off in torque below 1,300rpm of the A-rated engine.
The torque improvement has been achieved by using a new fuel pump/turbocharger combination, and valve timing has been modified by changes to the camshaft. This has given a larger overlap, which Volvo claims has improved breathing.
Piston ring friction has been reduced by fitting fewer rings (now three). The top ring is now lower down the crown, which has dropped the temperature by around 25°C (77°F).