Snow groomer and relative control method

1. A snow groomer comprising a first and second track; an internal combustion engine; a power transmission; a plurality of working devices connected to the internal combustion engine by the power transmission; a user interface; and a control unit comprising a first computing block for determining a total power demand of said working devices, and a second computing block for determining a work point in a characteristic graph of the internal combustion engine as a function of total power demand and the fuel consumption of the internal combustion engine; wherein the second computing block determines the work point in the characteristic graph of the internal combustion engine as a function of a power reserve of the internal combustion engine.

2. A snow groomer as claimed in claim 1 , wherein the work point is defined by a power output of the internal combustion engine equal to total power demand, and defines a work speed of the internal combustion engine.

3. A snow groomer as claimed in claim 1 , wherein the second computing block comprises at least one operating curve defined on the basis of the fuel consumption of the internal combustion engine and a maximum power output; and wherein the work point is located along the operating curve.

4. A snow groomer as claimed in claim 3 , wherein the operating curve can be adjusted to optimize fuel consumption, or increase a power reserve, or balance the power reserve and optimum fuel consumption.

5. A snow groomer as claimed in claim 4 , wherein the user interface comprises a selector device for adjusting the operating curve; and the second computing block comprises a memory for storing a plurality of different operating curves; the second computing block being connected to the user interface to receive a selection command to select the operating curve from the plurality of operating curves.

6. A snow groomer as claimed in claim 2 , wherein the second computing block is configured to determine the work speed of the internal combustion engine as a function of the operating curve.

7. A snow groomer as claimed in claim 1 , wherein the second computing block is configured to determine a work torque of the internal combustion engine as a function of the work point.

8. A snow groomer as claimed in claim 7 , comprising adjusting means for adjusting a velocity ratio of the power transmission, so as to apply to the internal combustion engine a resisting torque substantially equal to the work torque.

9. A snow groomer as claimed in claim 1 , wherein the power transmission comprises at least one electric generator connected mechanically to the internal combustion engine; and at least one electric actuator.

10. A snow groomer as claimed in claim 1 , wherein the power transmission comprises at least one hydraulic pump connected mechanically to the internal combustion engine; and at least one hydraulic actuator connected functionally to one of the working devices, and hydraulically to the hydraulic pump.

11. A snow groomer as claimed in claim 1 , wherein the second computing block comprises a memory storing a priority level for each working device; the second computing block acting on the power transmission to power each working device according to its assigned priority level.

12. A snow groomer as claimed in claim 1 , wherein said working devices comprise a first and second drive wheel connected respectively to the first and second track; the user interface comprising a first control device for selecting a travelling speed of the snow groomer; the user interface; and the control unit.

13. A snow groomer as claimed in claim 1 , and comprising a radiator for cooling the power transmission; and a hydraulic circuit for connecting the radiator to the power transmission; the power transmission preferably being electric.

14. A snow groomer as claimed in claim 13 , wherein the power transmission comprises at least one liquid-cooled driver device connected to the radiator by the hydraulic circuit.

15. A snow groomer as claimed in claim 13 , wherein the power transmission comprises a generator and/or at least one electric actuator liquid-cooled and connected to the radiator by the hydraulic circuit; and the snow groomer comprises a liquid-cooled electric resistor connected to the radiator by the hydraulic circuit.

16. A snow groomer as claimed in claim 3 , wherein the second computing block is configured to determine the work speed of the internal combustion engine as a function of the operating curve.

17. A snow groomer as claimed in claim 9 wherein the actuator is an electric motor, connected functionally to one of the working devices, and electrically to the electric generator.

18. A snow groomer as claimed in claim 12 wherein the user interface comprises a second control device for selecting a turn angle of the snow groomer; and wherein the control unit is connected to the first and second control device and to the power transmission to determine a first desired speed of the first drive wheel and a second desired speed of the second drive wheel as a function of the operating configurations of the first and second control device.

19. A method of controlling a snow groomer; the snow groomer comprising a first and second track; an internal combustion engine; a power transmission; a plurality of working devices connected to the internal combustion engine by the power transmission; and a user interface; the method comprising the steps of determining a total power demand of said working devices; and determining a work point in a characteristic graph of the internal combustion engine as a function of total power demand, the fuel consumption and a power reserve of the internal combustion engine.

20. A method as claimed in claim 19 , comprising the steps of defining an operating curve in said characteristic graph; and selecting the work point along the operating curve; and wherein the step of defining the operating curve in said characteristic graph comprises selecting said operating curve from a plurality of operating curves predefined as a function of fuel consumption and a power reserve.

21. A method as claimed in claim 19 , comprising the step of determining a work torque of the internal combustion engine as a function of the work point.

22. A method as claimed in claim 21 , comprising the step of adjusting a velocity ratio of the power transmission, so as to apply to the internal combustion engine a resisting torque substantially equal to the work torque.

23. A method as claimed in claim 19 , comprising the step of assigning a priority level to each working device, and powering each working device via the power transmission according to the assigned priority level.