Increasing efficiency without reducing consumption is a mainstream of all tractor constructors. Several solutions are available: engine of less displacement and number of cylinders able to be undergone to typical mission profile of medium power range tractor, engine of high power used at low engine speed, reduced range of work with high power and low consumption, very reactive engines at low engine speed, optimized transmissions in order to reduce losses of power, automatic transmission able to keep engine in the ideal working conditions, optimization of accessories like fan both for design and for speed management. SDF group is started from a blank paper in order to design a new series of tractor from 100 to 130 hp with ground vehicle weight (GVW) higher than 8 ton. There were two available ways: start from the previous powertrain, or design and optimize specific components such as engine and transmission. SDF has chosen the second way according to the lighter mission profile together with increasing of high inertia implements, vehicle speed, trailer dimension and an higher use of tractor on asphalt. 3.6 litres engine in place of that higher than 4 litres, high dynamic behaviour at low engine speed, automatic PTO. During tractor design for road application with small size engine, one of the problems consists in the engine brake due to eco gears at economic speed, because the effect of engine brake becomes null.
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