METHOD FOR CONTROLLING POWERTRAIN, AND POWERTRAIN

Abstract

Method for controlling a powertrain (1) of a vehicle and a powertrain, which powertrain comprises a diesel engine (2), an electric generator (3), a generator drive (4), at least one electric motor (5, 6), at least one electric motor drive (7, 8), operator input devices (11), and a control system (12), wherein the control system (12) controls at least some of the parts of the powertrain (1) based on information obtained from the operator input devices (11) and at least one measuring signal obtained from the diesel engine (2), from the generator drive (4), and from the at least one electric motor drive (7, 8).

Claims

1. A method for controlling a powertrain of a vehicle, which powertrain comprises a diesel engine, an electric generator, a generator drive, at least one electric motor, at least one electric motor drive, operator input devices, and a control system, wherein the control system controls at least some of the parts of the powertrain based on information obtained from the operator input devices and at least one measuring signal obtained from the diesel engine, from the generator drive, and from the at least one electric motor drive.

2. The method of claim 1, wherein the control system controls the diesel engine, the generator drive and/or the at least one electric motor drive of the powertrain, and wherein the control system controls the diesel engine via an electronic control unit of the diesel engine and via the electronic control unit an engine brake system of the diesel engine.

3. The method of claim 1, wherein the at least one measuring signal defines a rotational speed of the diesel engine, a rotational speed of the generator, electrical power generation of the generator, and electrical power consumption of the at least one electrical motor drive.

4. The method of claim 2, wherein the control system activates an engine braking system of the diesel engine when the control system receives measuring signal indicating increase in the diesel engine's RPM over predefined activation threshold value without corresponding change input from the operator input devices

5. The method of claim 4, wherein the control system also activates axle brakes, apply auxiliary loads and/or reduces the vehicle speed.

6. The method of claim 1 wherein electrical power from the generator is conveyed directly from the generator drive to the at least one electric motor drive.

7. The method of claim 6, wherein excess electrical power from the generator is conveyed to an energy storage, and additional electrical power is conveyed from the energy storage to the at least one electric motor drive.

8. The method of claim 1, wherein the operator input devices allow operator selection from a plurality of predefined settings of the powertrain operating parameters.

9. A powertrain comprising a diesel engine, an electric generator, a generator drive, at least one electric motor, an electric motor drive for each electric motor, operator input devices, and a control system for controlling an operation of the diesel engine, the generator, and the at least one electric motor, wherein the control system is configured to control the operation of at least one of the diesel engine, the generator, and the at least one electric motor based on at least one received measuring signal, which measuring signal defines rotational speed of the diesel engine, measured power of the at least one electric motor, and the rotational speed and torque of the at least one electric motor.

10. The powertrain of claim 9, wherein the diesel engine comprises an electronic control unit and an engine brake system, which engine brake system preferably comprise an exhaust brake and/or compression release engine brake.

11. The powertrain of claim 9, wherein the generator drive is electrically directly connected to the electric motor drive.

12. The powertrain of claim 10 or 11, wherein the control system is configured to apply engine brake system via the electronic control unit of the diesel engine when the at least one measuring signal indicates increase in the diesel engine's rotational speed over predefined activation threshold value.

13. The powertrain of claim 12, wherein the powertrain comprises an energy storage, which energy storage is connected between the generator drive and the electric motor drive and in parallel connection with the electrical direct connection between the generator drive and the electric motor drive.

14. A mining or tunnelling vehicle comprising the powertrain according to claim 8.

15. A computer program configured to perform the method of claim 1, when run in a computer.

16. The method of claim 3, wherein the control system activates the engine braking system of the diesel engine when the control system receives measuring signal indicating increase in the diesel engine's RPM over predefined activation threshold value without corresponding change input from the operator input devices.

17. The method of claim 16, wherein the control system also activates axle brakes, apply auxiliary loads and/or reduces the vehicle speed.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0028] The exemplary embodiments of the invention are explained with reference to the accompanying figures, where

[0029] FIG. 1 shows schematically an embodiment of a powertrain of the invention,

[0030] FIG. 2 shows a functional diagram of an embodiment of the control operations of the invention, and

[0031] FIG. 3 shows schematically an embodiment of a vehicle for a powertrain of the invention.

DETAILED DESCRIPTION OF THE FIGURES

[0032] In FIG. 1 is shown schematically the main parts of an embodiment of a diesel-electric or hybrid powertrain 1 in accordance with the present invention.

[0033] The powertrain 1 comprises a diesel engine 2, which rotates a generator 3 for creating electricity. To the generator 3 is connected a generator drive 4. The generator drive 4 controls the generator 3 for obtaining the required electrical current and voltage from the generator, and provides the operating electrical power for a front electric motor 5 and a rear electric motor 6 of the vehicle and the respective drives 7 and 8 controlling these motors. The motors 5 and 6 rotate traction members of the vehicle, such as tires (not shown), for example.

[0034] The diesel engine 2 is equipped with an electric control unit (ECU) 9 and an integrated engine brake system comprising an exhaust brake 10. The ECU 9 controls both the diesel engine 2 and the engine brake system comprising the exhaust brake 10. In addition to the exhaust brake 10, or alternatively, the engine brake system may comprise a compression release brake or some other form of a brake.

[0035] The powertrain 1 also comprises a control system 12 controlling the operation of the powertrain based on the instruction received from operator input devices 11, such as gas and brake pedals, for example. The instructions received from the operator input devices 11 are in form of signals representing reference values, such as speed, torque and/or power for example.

[0036] In the embodiment of FIG. 1 the control system 12 controls the generator drive 4, the ECU 9 of the diesel engine 2, as well as the drives 7 and 8 of the electric motors 5 and 6. Additionally the control system 12 may also control auxiliary loads and/or axle brakes.

[0037] The generator drive 4 provides information of the generator's 3 rotational speed and/or the electrical power produced by the generator to the control system 12.

[0038] The ECU 9 provides information of the diesel engine's 2 rotational speed to the control system 12, in addition to other required information such as load information, etc.

[0039] The electric motor drives 7 and 8 provide information of the electric motor's 5 and 6 rotational speed and torque, and/or the actual electrical power used by the electric motors 5 and 6 to the control system 12.

[0040] Based on the information received from the generator drive 4, the ECU 9, the electric motor drives 7 and 8, as well as from the operator input devices, the control system 12 controls the powertrain in a way discussed in following with reference to FIG. 2.

[0041] FIG. 2 shows a functional diagram of an embodiment of the operations of the controlling of the powertrain in accordance with the invention, such as shown in FIG. 1, for example.

[0042] In the normal operation of the powertrain 1, the control system 12 controls the powertrain with speed, power and/or torque requests to the electric motor drives 7 and/or 8 to maintain the present operating parameters. The electric motor drives 7 and 8 control the electric motors 5 and 6 to fulfil the requests from the control system 12 within external or internal limit values to move the vehicle.

[0043] Changes in the control operations of the powertrain 1 are initiated either by the operator of the vehicle equipped with the powertrain via operator input devices 11, as shown in box 101, or by change in the measurement signals received by the control system 12 from the components of the powertrain, such as electric motor drives 7 and/or 8, for example, as shown in box 102.

[0044] Operator initiated change via the operator input devices 11 sets a new reference values for the control system 12, based on which the control system starts to control the powertrain 1 for obtaining these. The change in the received measurement signal or signals typically originate from changed environmental factors, such as from a change in degree of a decline or ascent in the travel path of the vehicle, for example.

[0045] After being notified or indicated of a change in the operating parameters of the powertrain 1, the control system 12 checks whether the present power consumption and power production capability of the powertrain 1 are at balance, as shown in box 103. If there is balance, i.e. sufficient additional power production is available with the present operating parameters of the powertrain 1 for implementing the change, then the present operating parameters of the powertrain and its components are maintained as shown in box 104, and the required additional power is produced by the generator 3 and provided for the electric motor drives 7 and 8.

[0046] In case the change requires less power for the electric motors drives 7 and 8, the control system 12 simultaneously checks whether the present power production capability exceeds the required power consumption, as also shown in box 103. In case the present power production capability does greatly exceed the required power consumption, the control system 12 proceeds also to optimize the rotational speed of the diesel engine 2, as also shown in box 104, in order to save fuel and lower the engine noise and exhaust gas created, for example.

[0047] If the power consumption and the power production capability in the powertrain 1 is not in balance, and the power production capability does not exceed the power demand, the control system 12 checks whether the power demand required for implementing the change is higher than present power production capability, as shown in box 105.

[0048] If the power demand for implementing the change is higher than the present power production capability, the control system 12 proceeds to increase the rotational speed on the diesel engine 2 for providing more electrical power production capacity for the powertrain 1 and at the same time limits the power consumption of the electrical motor drives 7 and 8 so that the diesel engine does not stall, until the power production capability of the powertrain exceeds the new higher power demand, as shown in box 106.

[0049] If the power demand of the change is not higher than the present power production capability of the powertrain 1, the control system checks whether the rotational speed of the diesel engine 2 is increasing, as shown in box 107.

[0050] If there is no increase in the rotational speed of the diesel engine 2, the control system 12 continues to maintain the present operating parameters of the powertrain 1 and its components, and also optimize the rotational speed of the diesel engine 2, as shown in box 108. The optimization of the rotational speed of the diesel engine 2 may comprise optimization of fuel consumption, noise level, after-treatment system, and/or responsiveness, for example. In case of fuel consumption optimization, the control system 12 adjusts the rotational speed of the diesel engine 2 to find optimum fuel consumption point while also maintaining the required power production capability and responsiveness.

[0051] If the rotational speed of the diesel engine 2 is increasing, the control system 12 checks whether the rotational speed of the diesel engine has reached its allowed maximum value, as shown in box 109.

[0052] If the maximum value of the rotational speed of the diesel engine 2 is not reached, the control system 12 starts to apply engine braking system of the diesel engine by controlling the ECU 9 of the diesel engine to control the diesel engine in accordance with a suitable engine braking method, and via the ECU the engine brake system, in order to provide additional braking power for the vehicle, as shown in box 110. This signifies the situation where the vehicle is travelling in descending slope, or deacceleration of the machine is requested by the operator, and the electric motors 5 and 6 start to act as generators and provide electrical power in the powertrain 1.

[0053] If the rotational speed of the diesel engine 2 has reached the allowed maximum value, then the control system 12 applies the engine braking system fully via the ECU 9, and also starts to apply additional braking means such as applying auxiliary loads, applying axle brakes of the vehicle and/or reduce the present speed parameters of the vehicle. In this situation the vehicle is travelling in a continuous descending slope in which its speed and momentum are exceeding, or at risk of exceeding, the input reference values, and the control system 12 applies all required means to stop the speed increase and get the vehicle speed back within acceptable parameters under those conditions.

[0054] In the present invention the operator input devices 11 can include means or device, such as a suitable selecting device, for the operator to select between a plurality of preset operating parameters of the powertrain. This selecting device corresponds substantially to a gearbox lever of a traditional powertrain. If, for example, the preset maximum rotational speed for the diesel engine 2 is 2000 RPM, then the predetermined operating parameters for the powertrain 1 can, for example, be the following: [0055] Level 1: Diesel engine's rotational speed is 1000 RPM, whereby allowed vehicle speed 0-7 km/h and electrical power max. 100 kW. [0056] Level 2: Diesel engine's rotational speed is 1250 RPM, whereby allowed vehicle speed 0-14 km/h and electrical power max. 150 kW. [0057] Level 3: Diesel engine's rotational speed is 1500 RPM, whereby allowed vehicle speed 0-21 km/h and electrical power max. 220 kW.

[0058] The above levels allow gear-like controlling the powertrain 1 via the control system 12 based on the selected level from the operator input devices 11.

[0059] Alternatively, or additionally, the control system 12 can control the rotational speed of the diesel engine 2 stepwise for example in the following way based on the actual measured electrical power from the electrical motor drives 7 and 8: [0060] When the measured power consumption is under 65 kW, the rotational speed is kept at 1000 RPM. [0061] When the measured power consumption is between 65 kW and 130 kW, the rotational speed is raised to 1400 RPM. [0062] When the measured power consumption is above 130 kW, the rotational speed is raised to 1800 RPM.

[0063] In this embodiment the changing of the rotational speed of the diesel engine 2 up is implemented preferably when the measured power exceeds the set maximum electrical power for 0.5 seconds. The change of rotational speed down is preferably implemented when the measured power is below the lower limit for 5 seconds.

[0064] FIG. 3 shows an embodiment of a vehicle 13 utilizing a powertrain of the invention. In this embodiment the vehicle is an agitator. Other suitable mining and tunneling vehicles include concrete spraying equipment, charging equipment, scaling equipment, underground logistics equipment, and lifting and installation equipment, for example. Especially suitable the powertrain of the invention is for equipment that are typically driven substantial amounts, such as the logistics equipment for example.

[0065] The invention has been explained above with reference to the above-mentioned exemplary embodiment and its several advantages have been demonstrated. It is clear that the invention is not only restricted to this embodiment, but it comprises all possible embodiments within the scope of the following claims.