VEHICLE AUXILIARY PUMP CONTROL

Abstract

A vehicle includes a main pump and an auxiliary pump, each configured to provide fluid to a hydraulic circuit. A motor is configured to drive the auxiliary pump. A controller is configured to determine a temperature of the motor, compare the temperature of the motor to a first predetermined operating threshold, and disable the auxiliary pump and enable the main pump if the temperature of the motor is above the first predetermined operating threshold. A method of controlling fluid flow in the vehicle includes determining a temperature of the motor, comparing the temperature to the first predetermined operating threshold, and disabling the auxiliary pump and enabling the main pump if the temperature of the motor is above the first predetermined operating threshold.

Description

TECHNICAL FIELD

The invention relates to control of the use of an auxiliary pump in a vehicle.

BACKGROUND

Passenger and commercial vehicles may use pumps driven by an engine or motor to provide fluid to various hydraulic devices in the vehicle. For example, the engine and/or motor may drive one or more pumps by providing a torque to the pump. The pump, in turn, provides pressurized fluid to hydraulic devices in the vehicle in accordance with the torque provided by the engine and/or motor.

SUMMARY

An example vehicle includes a main pump, an auxiliary pump, a motor, and a controller. The main pump and the auxiliary pump are each configured to provide fluid to a hydraulic circuit. The motor is configured to drive the auxiliary pump. The controller is configured to determine a temperature of the motor and compare the temperature of the motor to a first predetermined operating threshold. The controller is further configured to disable the auxiliary pump and enable the main pump if the temperature of the motor is above the first predetermined operating threshold.

A method of controlling fluid flow in a vehicle includes determining a temperature of a motor driving the auxiliary pump, comparing the temperature to a first predetermined operating threshold, and disabling the auxiliary pump if the temperature of the motor is above the first predetermined operating threshold. The method also includes enabling a main pump if the temperature of the motor is above the first predetermined operating threshold.

The above features and the advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an example vehicle configured to control an auxiliary pump.

FIG. 2 is a flowchart of an example process that may be implemented to control the auxiliary pump.

FIG. 3 is a flowchart of another example process that may be implemented to control the auxiliary pump.

DETAILED DESCRIPTION

A vehicle is provided with a main pump, an auxiliary pump, a motor, and a controller. The main pump and the auxiliary pump are each configured to provide fluid to a hydraulic circuit. The motor is configured to drive the auxiliary pump. The controller is configured to determine a temperature of the motor and compare the temperature of the motor to a first predetermined operating threshold. The controller is further configured to disable the auxiliary pump and enable the main pump if the temperature of the motor is above the first predetermined operating threshold. Accordingly, the controller may prevent the motor from failing if the motor begins to overheat. The controller may be further configured to allow the motor to turn back on after the motor has had time to cool. This way, the controller may control the operation of the auxiliary pump to prevent the motor from overheating.

FIG. 1 illustrates a vehicle 100 able to determine whether a motor is in danger of overheating, and if so, take appropriate remedial action (e.g., disable an auxiliary pump). The vehicle 100 may take many different forms and include multiple and/or alternate components and facilities. While an example vehicle 100 is shown in the Figures, the components illustrated in the Figures are not intended to be limiting. Indeed, additional or alternative components and/or implementations may be used.

The vehicle 100 may include an engine 105, a motor 110, a temperature sensor 115, a main pump 120, an auxiliary pump 125, a hydraulic circuit 130, and a controller 135. The vehicle 100 may include any automobile having two pumps driven by different sources. For example, the vehicle 100 may be any passenger or commercial automobile such as a hybrid electric vehicle including a plug-in hybrid electric vehicle (PHEV) or an extended range electric vehicle (EREV), a gas-powered vehicle, or the like.

The engine 105 may include any device configured to generate torque from a fuel. For instance, the engine 105 may include an internal combustion engine configured to output torque via a crankshaft by burning a mixture of fuel and air. In one possible implementation, the torque from the engine 105 may be output to a transmission or gearbox (not shown). Further, the torque from the engine 105 may be used to drive one or more other devices, such as the main pump 120, which is described in detail below. Further, the operation of the engine 105 may be controlled by an engine control unit (not shown).

The motor 110 may include any device configured to convert electrical energy into a torque. That is, the motor 110 may receive electrical energy from a power source (not shown) such as a battery and provide a torque via an output shaft using the electrical energy. For example, the motor 110 may include a stator, a rotor, and a commutator. The stator may include any device configured to receive the electrical energy from the power source and generate a magnetic field with the electrical energy. The rotor may include any device configured to rotate relative to the stator when the stator is provided with the electrical energy. That is, the rotor may be configured to rotate in response to the magnetic field produced by the stator. The commutator may include any device configured to help the rotor maintain rotational motion, and thus, help the motor 110 provide torque. The output shaft may be disposed on the rotor such that the rotor and the output shaft rotate at substantially the same speeds. In one possible approach, the motor 110 may further act as a generator and store electrical energy in the power source if, for example, the motor 110 is provided with a torque. For example, the engine 105 may provide the motor 110 with a torque by using a belt (not shown) operably connected to the crankshaft of the engine 105 and the output shaft of the motor 110. The operation of the motor 110 may be controlled by a motor control unit (not shown).

The temperature sensor 115 may include any device configured to measure a temperature of the motor 110. The temperature sensor 115 may be operatively disposed on or near the motor 110 and may be configured to generate a signal representative of the temperature of the motor 110. For example, the temperature sensor 115 may be configured to directly or indirectly measure the temperature of the stator, the rotor, or electronics used to drive the motor 110. In one possible implementation, the temperature of the motor 110 may be estimated without the use of the temperature sensor 115 as discussed in further detail below.

The main pump 120 may include any device configured to provide fluid at a commanded pressure when provided with a torque. For instance, the main pump 120 may be configured to receive the torque generated by the engine 105 via the crankshaft and provide fluid at a pressure based on the torque from the engine 105. Thus, the main pump 120 may be configured to provide fluid at any time the engine 105 is enabled.

The auxiliary pump 125 may include any device configured to provide fluid at a commanded pressure when provided with a torque. For instance, the auxiliary pump 125 may be configured to receive the torque generated by the motor 110 via the output shaft and provide fluid at a pressure based on the torque from the motor 110. Thus, the main pump 120 may be configured to provide fluid at any time the motor 110 is enabled.

The hydraulic circuit 130 may include any device configured to provide fluid to one or more hydraulic components of the vehicle 100. The hydraulic circuit 130, therefore, may include a valve body, one or more valves, one or more clutch assemblies, etc., or any other hydraulic device configured to operate when provided with pressurized fluid. The hydraulic circuit 130 may be operatively connected to the main pump 120, the auxiliary pump 125, or both. This way, the main pump 120, the auxiliary pump 125, or both, may provide fluid to the hydraulic devices of the hydraulic circuit 130. Of course, the vehicle 100 may have any number of hydraulic circuits 130 operatively connected to one or both of the main pump 120 and the auxiliary pump 125.

The controller 135 may include any device configured to control various aspects of the vehicle 100. For example, in some circumstances, the controller 135 may be configured to command the engine 105, motor 110, or both to turn on or off. For example, the controller 135 may be configured to command the motor 110 on and the engine 105 off when the power source can supply a sufficient amount of electrical energy for the motor 110 or another motor (not shown) to propel the vehicle 100. If, however, the electrical energy stored in the power source drops below a certain level, the controller 135 may be configured to command the engine 105 to turn on to provide torque to the motor 110 to cause the motor 110 to generate electricity that may be stored in the power source. Alternatively, the controller 135 may command the engine 105 to turn on to provide torque to a transmission (not shown) to propel the vehicle 100 directly. Accordingly, the controller 135 may control different operating modes of the vehicle 100 based on whether the engine 105, the motor 110, or both are commanded on.

The controller 135 may be further configured to command the motor 110 and/or engine 105 on or off for reasons other than to propel the vehicle 100. For example, the controller 135 may command the motor 110 on or off to control the operation of the auxiliary pump 125 and the controller 135 may command the engine 105 on or off to control the operation of the main pump 120. The controller 135 may do so for various reasons, such as to reduce motor failure if the motor 110 driving the auxiliary pump 125 becomes too hot.

In one possible approach, the controller 135 may be configured to determine a temperature of the motor 110 and compare the temperature of the motor 110 to a first predetermined operating threshold, which may represent the maximum temperature at which the motor 110 may operate. The controller 135 may be configured to receive the temperature measured by the temperature sensor 115. Alternatively, the controller 135 may estimate the temperature of the motor 110 based on various factors such as the amount of current provided to the motor 110 from the power source, the speed of the motor 110, the amount of torque generated by the motor 110, etc.

If the temperature of the motor 110 is above the first predetermined operating threshold, the controller 135 may be configured to disable the motor 110 to disable the auxiliary pump 125 and enable the main pump 120 to provide fluid to the hydraulic circuit 130. To disable the auxiliary pump 125, the controller 135 may be configured to transmit a control signal to the motor 110 that commands the motor 110 to turn off. To enable the main pump 120, the controller 135 may be configured to transmit a control signal that commands the engine 105 to turn on. Additionally, the controller 135 may set a flag indicating that the motor 110 may not be commanded on despite other requests for torque from the motor 110. When the flag is set, the controller 135 may cause the engine 105 to generate the torque requested by the motor 110, including the torque to drive the main pump 120 to provide fluid to the hydraulic circuit 130.

If the temperature falls below a second predetermined operating threshold, the controller 135 may be configured to allow the auxiliary pump 125 to be enabled. For example, the controller 135 may be configured to clear the flag and allow the motor 110 to provide torque to the auxiliary pump 125. Clearing the flag may indicate that the auxiliary pump 125 is available for use. That is, once the flag is clear, the controller 135 may be configured to allow the main pump 120 to be disabled (e.g., when the engine 105 is commanded off). However, the controller 135 need not immediately disable the main pump 120 and enable the motor 110 when the flag is clear. For example, the vehicle 100 may be operating in an “engine only” mode (e.g., only the engine 105 is commanded on to propel the vehicle) when the flag is cleared. Clearing the flag may allow the controller 135 to command the motor 110 to turn on when the vehicle 100 is no longer operating in the “engine only” mode. The first and second predetermined operating thresholds may represent the same or different temperatures. If different temperatures, the controller 135 may give the motor 110 additional time to cool even after the temperature of the motor 110 has fallen below the first predetermined operating threshold.

In general, computing systems and/or devices, such as the controller 135, the engine control unit, the motor control unit, etc., may employ any of a number of computer operating systems and generally include computer-executable instructions, where the instructions may be executable by one or more computing devices such as those listed above. Computer-executable instructions may be compiled or interpreted from computer programs created using a variety of well known programming languages and/or technologies, including, without limitation, and either alone or in combination, Java™, C, C++, Visual Basic, Java Script, Perl, etc. In general, a processor (e.g., a microprocessor) receives instructions, e.g., from a memory, a computer-readable medium, etc., and executes these instructions, thereby performing one or more processes, including one or more of the processes described herein. Such instructions and other data may be stored and transmitted using a variety of known computer-readable media.

A computer-readable medium (also referred to as a processor-readable medium) includes any non-transitory (e.g., tangible) medium that participates in providing data (e.g., instructions) that may be read by a computer (e.g., by a processor of a computer). Such a medium may take many forms, including, but not limited to, non-volatile media and volatile media. Non-volatile media may include, for example, optical or magnetic disks and other persistent memory. Volatile media may include, for example, dynamic random access memory (DRAM), which typically constitutes a main memory. Such instructions may be transmitted by one or more transmission media, including coaxial cables, copper wire and fiber optics, including the wires that comprise a system bus coupled to a processor of a computer. Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, an EPROM, a FLASH-EEPROM, any other memory chip or cartridge, or any other medium from which a computer can read.

FIG. 2 illustrates an example process 200 that may be implemented by the controller 135 to control the use of the auxiliary pump 125 to, for example, protect the motor 110 from overheating.

At block 205, the controller 135 may determine the temperature of the motor 110. For example, the controller 135 may receive the signal generated by the temperature sensor 115 or estimate the temperature based on factors such as the amount of current provided to the motor 110 from the power source, the speed of the motor 110, the amount of torque generated by the motor 110, etc.

At decision block 210, the controller 135 may compare the temperature determined at block 205 to the first predetermined operating threshold. The first predetermined operating threshold may represent the maximum temperature at which the controller 135 will allow the motor 110 to operate before disabling the motor 110. If the temperature is below the first predetermined operating threshold, the process 200 may continue at block 205. If the temperature is above the predetermined operating threshold, the process 200 may continue at block 215.

At block 215, the controller 135 may disable the auxiliary pump 125. For example, the controller 135 may command the motor 110 to turn off. As discussed above, the torque provided by the motor 110 drives the auxiliary pump 125. Thus, commanding the motor 110 to turn off will disable the auxiliary pump 125 and the process 200 may continue at block 220.

At block 220, the controller 135 may enable the main pump 120 by, for instance, commanding the engine 105 to turn on. As discussed above, the torque provided by the engine 105 drives the main pump 120. Accordingly, commanding the engine 105 to turn on causes the main pump 120 to provide fluid to the hydraulic circuit 130. As such, the hydraulic circuit 130 may still receive fluid if the temperature of the motor 110 is above the first predetermined operating threshold.

FIG. 3 illustrates another example process 300 that may be implemented by the controller 135 to control the use of the auxiliary pump 125 to, for example, protect the motor 110 from overheating.

At block 305, the controller 135 may determine the temperature of the motor 110. For example, the controller 135 may receive the signal generated by the temperature sensor 115 or estimate the temperature based on factors such as the amount of current provided to the motor 110 from the power source, the speed of the motor 110, the amount of torque generated by the motor 110, etc.

At decision block 310, the controller 135 may compare the temperature determined at block 305 to the first predetermined operating threshold. As previously discussed, the first predetermined operating threshold may represent the maximum temperature at which the controller 135 will allow the motor 110 to operate before disabling the motor 110. If the temperature is below the first predetermined operating threshold, the process 300 may continue at block 305. If the temperature is above the predetermined operating threshold, the process 300 may continue at block 315.

At block 315, the controller 135 may set a flag indicating that the motor 110 may not be commanded on despite requests for torque from the motor 110. Therefore, the controller 135 and other electronic devices such as the motor control unit may be unable to command the motor 110 to turn on when the flag is set. Further, setting the flag may further indicate that the auxiliary pump 125 is not available for use.

At block 320, the controller 135 may command the motor 110 to turn off. As discussed above, commanding the motor 110 to turn off may cause the auxiliary pump 125 to cease providing fluid to the hydraulic circuit 130. Additionally, turning the motor 110 off will allow the motor 110 to cool.

At block 325, the controller 135 may command the engine 105 to turn on to, for example, drive the main pump 120 and provide fluid to the hydraulic circuit 130. As discussed above, the flag set at block 315 may indicate that the auxiliary pump 125 is not available for use. The controller 135 may command the engine 105 on and thus enable the main pump 120 to provide fluid to the hydraulic circuit 130 so that the hydraulic circuit 130 may still operate despite the temperature of the motor 110.

At block 330, the controller 135 may determine the temperature. For instance, the controller 135 may estimate the temperature of the motor 110 or receive the measured temperature from the temperature sensor 115.

At decision block 335, the controller 135 may compare the temperature measured at block 330 to the second predetermined operating threshold. The second predetermined operating threshold may represent a temperature at which the motor 110 may be enabled without significant risk of overheating. If the temperature measured at block 330 is above the second predetermined operating threshold, the process 300 may continue at block 330. If, however, the temperature of the motor 110 measured at block 330 is below the second predetermined threshold, the process 300 may continue at block 340.

At block 340, the controller 135 may clear the flag to allow the motor 110 to turn on to drive the auxiliary pump 125. Clearing the flag may indicate that the auxiliary pump 125 is available for use. That is, once the flag is clear, the controller 135 may allow the main pump 120 to be disabled (e.g., when the engine 105 is commanded off). However, the controller 135 need not immediately disable the main pump 120 and enable the motor 110 when the flag is clear. For example, the vehicle 100 may be operating in an “engine only” mode (e.g., only the engine 105 is commanded on to provide torque to the wheels) when the flag is cleared. Clearing the flag may allow the motor 110 to be commanded on when the vehicle 100 is no longer operating in the “engine only” mode.

While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.

Claims

1. A vehicle comprising:

a main pump configured to provide fluid to a hydraulic circuit;

an auxiliary pump configured to provide fluid to the hydraulic circuit;

a motor configured to drive the auxiliary pump; and

a controller configured to determine a temperature of the motor, compare the temperature of the motor to a first predetermined operating threshold, and disable the auxiliary pump and enable the main pump if the temperature of the motor is above the first predetermined operating threshold.

2. A vehicle as set forth in claim 1, further comprising a sensor configured to measure the temperature of the motor.

3. A vehicle as set forth in claim 1, wherein the controller is configured to estimate the temperature of the motor.

4. A vehicle as set forth in claim 1, wherein the controller is configured to allow the auxiliary pump to be enabled if the temperature of the motor falls below a second predetermined operating threshold.

5. A vehicle as set forth in claim 4, wherein the first predetermined operating threshold and the second predetermined operating threshold each represents a different temperature.

6. A vehicle as set forth in claim 1, further comprising an engine configured to provide a torque to drive the main pump.

7. A vehicle as set forth in claim 1, wherein the motor is configured to provide a torque to drive the auxiliary pump.

8. A vehicle as set forth in claim 1, wherein the controller is configured to disable the auxiliary pump by generating a control signal that commands the motor to turn off.

9. A vehicle as set forth in claim 1, further comprising an engine configured to drive the main pump, and wherein the controller is configured to enable the main pump by generating a control signal that commands the engine to turn on.

10. A method of controlling fluid flow in a vehicle, the method comprising:

determining a temperature of a motor driving the auxiliary pump;

comparing the temperature to a first predetermined operating threshold;

disabling the auxiliary pump if the temperature of the motor is above the first predetermined operating threshold; and

enabling a main pump if the temperature of the motor is above the first predetermined operating threshold.

11. A method as set forth in claim 10, wherein disabling the auxiliary pump includes commanding the motor to turn off.

12. A method as set forth in claim 10, wherein enabling the pump includes commanding an engine driving the main pump to turn on.

13. A method as set forth in claim 10, further comprising allowing the motor to turn on to drive the auxiliary pump and allowing the main pump to be disabled if the temperature is below a second predetermined operating threshold.

14. A method as set forth in claim 10, wherein determining the temperature of the motor includes measuring the temperature of the motor with a sensor.

15. A method as set forth in claim 10, wherein determining the temperature of the motor includes estimating a temperature of the motor.

16. A method as set forth in claim 10, wherein disabling the auxiliary pump includes setting a flag indicating that the auxiliary pump is not available for use.

17. A method as set forth in claim 16, further comprising clearing the flag if the temperature of the motor is below a second predetermined operating threshold.

18. A vehicle comprising:

a main pump configured to provide fluid to a hydraulic circuit;

an auxiliary pump configured to provide fluid to the hydraulic circuit;

a motor configured to drive the auxiliary pump by providing a torque to the auxiliary pump;

an engine configured to drive the main pump by providing a torque to the main pump; and

a controller configured to determine a temperature of the motor, compare the temperature of the motor to a first predetermined operating threshold, and disable the auxiliary pump and enable the main pump if the temperature of the motor is above the first predetermined operating threshold, wherein the controller is configured to disable the auxiliary pump by commanding the motor to turn off and enable the main pump by commanding the engine to turn on; and

wherein the controller is configured to allow the auxiliary pump to be enabled if the temperature of the motor falls below a second predetermined operating threshold.

19. A vehicle as set forth in claim 18, further comprising a sensor configured to measure the temperature of the motor.

20. A vehicle as set forth in claim 18, wherein the controller is configured to estimate the temperature of the motor.