Electric powertrain work modes
A control system for off-highway battery application powertrain systems that allows the operator to select one or more performance/operating modes. The one or more performance modes may be based on the work that needs to be accomplished using the machine vs. the hours needed before the next charge opportunity. Modes will take typically into consideration battery management system performance maps, Electric motor/inverter performance maps, pump performance maps and other systems communicating with the powertrain system. The operator is in control to optimize refill and/or next battery charge. The operator may have the option to select performance modes based on excavator performance vs. battery life. Remaining time and warning messages may be periodically sent to the operator based on the performance mode selected and current state of charge.
1 . A controller for a hydraulically operated off-highway vehicle, comprising:
data storage for storing (a) a first efficiency map for a variable displacement hydraulic pump of the vehicle which provides data about efficiency relative to pump displacement and pump speed at a set of different operating pressures, and (b) a second efficiency map for an electric motor of the vehicle which provides data about efficiency relative to motor speed and motor torque, the motor being operable to drive the pump, the controller operable to:
display, on a user interface, a plurality of efficiency modes associated with the vehicle, wherein a subset of modes in the plurality of efficiency modes is selectable by a user, and the subset of modes is limited based on a state of charge of an electrical power source carried on the vehicle;
receive, from the user via the user interface, a user-selected mode that is selected by the user from the subset of modes;
adjust, based on the user-selected mode and the state of charge of the electrical power source, the motor speed and the pump displacement; and
iterate, based on the first and second efficiency maps, the pump speed and the pump displacement to provide a maximum overall efficiency of the motor and the pump.
2 . The controller of claim 1 , wherein the controller is operable to set upper and/or lower torque limits for the electric motor based on the state of charge of the electrical power source or H2 levels in storage tank, and based on the second efficiency map.
3 . The controller of claim 1 , wherein the controller in one efficiency mode is operable to set upper displacement and/or flow rate limits for the pump based on the state of charge of the electrical power source, based on the first efficiency map, and responsive to user input to set an upper flow limit.
4 . The controller of claim 1 , wherein the controller is operable to estimate a remaining time before the electrical power source will need recharging, based on the user-selected mode and the state of charge of the electrical power source.
5 . The controller of claim 4 , wherein the controller is operable to cause the remaining time estimate to be displayed on the user interface.
6 . The controller of claim 1 , wherein the controller is operable to estimate a remaining time before the electrical power source will need recharging, based on an efficiency mode which is not currently selected, and the state of charge of the electrical power source.
7 . The controller of claim 1 , wherein the controller is operable to automatically change to a more efficient mode if the state of charge of the electrical power source goes below a predetermined threshold.
8 . The controller of claim 1 , wherein the electrical power source comprises a battery or a fuel cell.
9 . The controller of claim 1 , wherein the controller is configured to further limit the subset of modes from being selectable by the user by removing from the user interface at least one mode from the subset of modes based on detecting or estimating further reduction in the state of charge of the electrical power source to prevent the user from selecting the at least one mode that is removed from the user interface.
10 . A hydraulically operated off-highway vehicle, the vehicle having a controller of claim 1 .
11 . A method of controlling a variable placement pump and a motor in a hydraulically operated off-highway vehicle, the method comprising the steps of:
(a) controlling pump displacement of the pump and motor speed of the motor;
(b) storing a first efficiency map for the pump which provides data about efficiency relative to the pump displacement and pump speed of the pump at a set of different operating pressures, and a second efficiency map which provides data about efficiency relative to the motor speed and motor torque of the motor;
(c) displaying, on a user interface, a plurality of operating modes associated with the vehicle, wherein a subset of modes in the plurality of operating modes is selectable by a user, and the subset of modes is limited based on a state of charge of an electrical power source carried on the vehicle;
(d) receiving, from the user via the user interface, a user-selected mode in the subset of modes that is selected by the user;
(e) adjusting, based on the user-selected mode and the state of charge of the electrical power source, the motor speed and the pump displacement; and
(f) iterating, based on the first and second efficiency maps, the pump speed and the pump displacement to provide a maximum overall efficiency of the motor and the pump.
12 . The method of claim 11 , further comprising: setting, based on the second efficiency map and the state of charge of the electrical power source, upper and/or lower torque limits for the motor.
13 . The method of claim 11 , further comprising: setting, responsive to a user input to set an upper flow limit and based on the first efficiency map and the state of charge of the electrical power source, upper displacement and/or flow rate limits for the pump.
14 . The method of claim 11 , further comprising: estimating, based on the user-selected mode and the state of charge of the electrical power source, a remaining time before the electrical power source will need recharging.
15 . The method of claim 14 , further comprising: displaying the remaining time estimate on the user interface.
16 . The method of claim 11 , further comprising: estimating, based on a mode in the subset of modes which is not the user-selected mode and the state of charge of the electrical power source, a remaining time before the electrical power source will need recharging.
17 . The method of claim 11 , further comprising: automatically changing operation of the vehicle to a more efficient mode from the subset of modes than the user-selected mode if the state of charge of the electrical power source goes below a predetermined threshold.
18 . The method of claim 11 , wherein the electrical power source comprises a battery or a fuel cell.
19 . The method of claim 11 , further comprising: limiting the subset of modes from being selectable by the user by removing from the user interface at least one mode from the subset of modes based on detecting or estimating further reduction in the state of charge of the electrical power source to prevent the user from selecting the at least one mode that is removed from the user interface.
20 . A computer-readable medium storing instructions that, when executed by a computer, cause the computer to perform the method of claim 11 .