Patent Application
20120271606
The present disclosure generally relates to the field of vehicles and, more specifically, to methods and systems for determining a temperature of a motor of a vehicle.
Automobiles and various other vehicles depend on motor operation. During operation of the vehicle, various vehicle systems may utilize an estimated motor temperature for use in controlling operation of the vehicle systems. Certain techniques utilize a motor coolant temperature to approximate the motor temperature, for example when an ignition of the vehicle has recently been started. However, the motor coolant temperature may not always provide an optimal estimate for the motor temperature, for example if the ignition had been turned off for only a relatively short period of time before being turned back on and/or if the weather is relatively warm outside the vehicle.
Accordingly, it is desirable to provide improved methods for determining a motor temperature of a vehicle, for example for an initial estimate of the motor temperature after the ignition has been turned on. It is also desirable to provide improved program products and systems for such estimation of a motor temperature of a vehicle. Furthermore, other desirable features and characteristics of the present invention will be apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
In accordance with an exemplary embodiment, a method for determining a temperature of a motor of a vehicle having an ignition when the ignition is turned on following a period of time in which the ignition had been turned off is provided. The method comprises the steps of determining an amount of time for which the vehicle had been turned off, and running a motor temperature model using a time step to simulate the amount of time for which the vehicle had been turned off to determine an initial value of the temperature of the motor.
In accordance with another exemplary embodiment, a program product for determining a temperature of a motor of a vehicle having an ignition when the ignition is turned on following a period of time in which the ignition had been turned off is provided. The program product comprises a program and a non-transitory, computer readable storage medium. The program is configured to determine an amount of time for which the vehicle had been turned off, and run a motor temperature model using a time step to simulate the amount of time for which the vehicle had been turned off to determine an initial value of the temperature of the motor. The non-transitory, computer readable storage medium stores the program.
In accordance with a further exemplary embodiment, a system for determining a temperature of a motor of a vehicle having an ignition when the ignition is turned on following a period of time in which the ignition had been turned off is provided. The system comprises a memory and a processor. The memory is configured to store an input. The processor is coupled to the memory. The processor is configured to determine an amount of time for which the vehicle had been turned off, and run a motor temperature model using the input and using a time step to simulate the amount of time for which the vehicle had been turned off to determine an initial value of the temperature of the motor.
The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or the application and uses thereof. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.
The system 100 includes a timer 110, sensors 112, and a controller 120. The timer 110 determines an amount of time during which the ignition 108 is turned off before the engine is turned on again in a current iteration. Specifically, the timer 110 preferably determines an amount of time beginning when the ignition 108 is keyed off (or turned off) and ending when the ignition 108 is keyed back on again (or turned on). The timer 110 provides the amount of time and/or information pertaining thereto to the controller 120 for processing and for use in determining temperature values for the motor 104.
The sensors 112 include an ambient temperature sensor 114, a motor coolant temperature sensor 116, and an ignition sensor 118. The ambient temperature sensor 114 measures an ambient temperature surrounding the vehicle, and provides these measurements and/or information pertaining thereto to the controller 120 for processing and for use in determining temperature values for the motor 104. The motor coolant temperature sensor 116 measures a temperature of the motor coolant 106 and provides these measurements and/or information pertaining thereto to the controller 120 for processing and for use in determining temperature values for the motor 104. The ignition sensor 118 senses whether the ignition 108 is turned on or off and provides signals and/or information pertaining thereto to the controller 120 for processing and for use in determining temperature values for the motor 104.
The controller 120 is coupled to the timer 110, the ambient temperature sensor 114, the motor coolant temperature sensor 116, and the ignition sensor 118. The controller 120 receives the signals as to whether the ignition 108 of the vehicle is turned on or off from the ignition sensor 118, and also receives values as to an amount of time that the ignition 108 has been turned off from the timer 110. In addition, the controller 120 receives the values of the ambient temperature from the ambient temperature sensor 114 and the motor coolant temperature from the motor coolant temperature sensor 116, respectively. The controller 120 processes these various signals and values in determining temperatures of the motor 104. In so doing, the controller 120 utilizes a motor temperature model using different step values and inputs, preferably in executing the steps of the processes 200, 300 described further below in connection with
As depicted in
In the depicted embodiment, the computer system 121 is coupled to the timer 110 and each of the sensors 112. The computer system 121 includes a processor 122, a memory 124, an interface 126, a storage device 128, and a bus 130. The processor 122 performs the computation and control functions of the computer system 121 and the controller 120, and may comprise any type of processor or multiple processors, single integrated circuits such as a microprocessor, or any suitable number of integrated circuit devices and/or circuit boards working in cooperation to accomplish the functions of a processing unit. During operation, the processor 122 executes one or more programs 132 contained within the memory 124 and, as such, controls the general operation of the controller 120 and the computer system 121, preferably in executing the steps of the processes 200, 300 described further below in connection with
The memory 124 can be any type of suitable memory, including, for example, various types of dynamic random access memory (DRAM) such as SDRAM, the various types of static RAM (SRAM), and the various types of non-volatile memory (PROM, EPROM, and flash). The bus 130 serves to transmit programs, data, status and other information or signals between the various components of the computer system 121. In a preferred embodiment, the memory 124 stores the above-referenced program 132 along with one or more stored values 134 and a motor temperature model 136. In certain examples, the memory 124 is located on and/or co-located on the same computer chip as the processor 122.
The interface 126 allows communication to the computer system 121, for example from a system driver and/or another computer system, and can be implemented using any suitable method and apparatus. It can include one or more network interfaces to communicate with other systems or components. The interface 126 may also include one or more network interfaces to communicate with technicians, and/or one or more storage interfaces to connect to storage apparatuses, such as the storage device 128.
The storage device 128 can be any suitable type of storage apparatus, including direct access storage devices such as hard disk drives, flash systems, floppy disk drives and optical disk drives. In one exemplary embodiment, the storage device 128 comprises a program product from which memory 124 can receive a program 132 that executes one or more embodiments of one or more processes of the present disclosure, such as the steps of the processes 200, 300 described further below in connection with
The bus 130 can be any suitable physical or logical means of connecting computer systems and components. This includes, but is not limited to, direct hard-wired connections, fiber optics, infrared and wireless bus technologies. During operation, the program 132 is stored in the memory 124 and executed by the processor 122.
It will be appreciated that while this exemplary embodiment is described in the context of a fully functioning computer system, those skilled in the art will recognize that the mechanisms of the present disclosure are capable of being distributed as a program product with one or more types of non-transitory computer-readable signal bearing media used to store the program and the instructions thereof and carry out the distribution thereof, such as a non-transitory computer readable medium bearing the program and containing computer instructions stored therein for causing a computer processor (such as the processor 122) to perform and execute the program. Such a program product may take a variety of forms, and the present disclosure applies equally regardless of the particular type of computer-readable signal bearing media used to carry out the distribution. Examples of signal bearing media include: recordable media such as floppy disks, hard drives, memory cards and optical disks, and transmission media such as digital and analog communication links. It will similarly be appreciated that the computer system 121 may also otherwise differ from the embodiment depicted in
As depicted in
Once the ignition is determined to be off, motor temperature values are stored for future use (step 204). Preferably, each motor temperature value comprises a temperature of the motor 104 of
A timer is run while the ignition is turned off (step 206). Preferably, the processor 122 controls the timer 110 to run once the ignition 108 is turned off and to continue to run until the ignition 108 of
In addition, an ambient temperature is obtained (step 212). The ambient temperature preferably comprises an air temperature of ambient air surrounding the vehicle. The ambient temperature is preferably measured by the ambient temperature sensor 114 of
A motor temperature model is then run for a first sequence of iterations (step 214). Specifically, the motor temperature model 136 of
The motor temperature model is then run for an additional sequence of iterations (step 216). In the additional sequence of iterations of the motor temperature model, a different time step is utilized. The time step for the additional sequence of iterations of step 216 is preferably smaller than the time step used for the first sequence of iterations of step 214. The time step for the first sequence of iteration may be as large as, but not limited to, five seconds (5 sec), while the time step for the second sequence of iteration is approximately 12.5 milliseconds (msec) in one exemplary embodiment. However, this may vary in other embodiments. The initial motor temperature values generated from step 214 are used as inputs for the motor temperature model in step 216, to thereby generate subsequent motor temperature values for the various nodes of the motor. The subsequent motor temperatures can then be utilized in controlling the motor and/or in controlling one or more other vehicle systems and/or devices of the vehicle.
As depicted in
A determination is then made as to whether an amount of time that the ignition has been turned off exceeds a predetermined threshold (step 304). The predetermined threshold of step 304 comprises a predetermined amount of time such that, if the ignition is not turned off for at least this predetermined amount of time, the motor temperature is not likely to have cooled enough to approach the motor coolant temperature. In one embodiment, the predetermined threshold of step 304 is calculated by multiplying a constant factor (k) by a time constant (τ). The constant (k) preferably varies between three (3) to five (5), and the time constant (t) preferably varies between 10 to 60 minutes (which is motor specific in a preferred embodiment). The predetermined threshold and/or the respective constant factor (k) and time constant (τ), are preferably stored in the memory 124 of
If it is determined in step 304 that the amount of time that the ignition has been turned off exceeds the predetermined threshold, then the motor temperature is assumed to have converged to the motor coolant temperature. The motor coolant temperature of is then measured (step 305), preferably by the motor coolant temperature sensor 116 of
Conversely, if it is determined in step 304 that the amount of time that the ignition has been turned off is less than or equal to the predetermined threshold, then the motor temperature is assumed to have not converged to the motor coolant temperature. The process then proceeds instead to step 308, as the motor temperature model is used to generate an initial motor temperature condition.
During step 308, the motor temperature model 136 of
Turning now to
Specifically, as depicted in
The various motor temperatures are calculated using various thermal resistance values depicted in
The motor temperature model utilizes the heat transfer coefficients and power dissipation loss calculations, along with the motor geometry, as inputs in creating a system of differential equations for each node 401-406. The system of differential equations is solved, to thereby generate a temperature change at each node for a given time step. The temperature change for each node is added to the current or most recent temperature for that node from a most recent prior iteration. Once the running of the motor temperature model is complete, a current temperature is determined for each node of the motor.
With reference again to
The inputs 306 also preferably include various thermal heat transfer coefficients 312 at a zero cooling flow of motor fluid, an ambient temperature 314 (preferably corresponding to the ambient temperature of step 212 of
During step 308, motor temperature values are generated for various nodes of the motor, thereby resulting in a first temperature value 320 for a first node (such as the first node 401 in
During each iteration of step 308, each preliminary temperature value 310 of the most recent previous iteration is added to a temperature change value generated by the motor temperature model to thereby generate the subsequent preliminary temperature value 310 of the current iteration (step 330). Steps 330 and 332 repeat in this manner for various iterations until it is determined that the simulated amount of elapsed time for the motor temperature model (given the time step 311) is equal to the amount of time of step 210 of
During step 338, the same motor temperature model is used to generate subsequent and more accurate determinations of present or current values of the temperature of the motor at various node of the motor. During step 338, the motor temperature model 136 of
The initial conditions 342 utilized in step 338 depend upon the determination of step 304 described above. Specifically, if it was determined in step 304 that the amount of time that the ignition has been turned off exceeds a predetermined threshold, then a first set 344 of initial conditions 342 is utilized for the motor temperature model in step 338. The first set 344 of initial conditions 342 comprises the motor coolant temperature of step 305.
Conversely, if it was determined in step 304 that the amount of time that the ignition has been turned off is less than or equal to the predetermined threshold, then a second set 346 of initial conditions 342 is utilized for the motor temperature model in step 338. The second set 346 of initial conditions 342 comprise the preliminary temperature values 310 from the most recent iteration of step 308.
During step 338, the motor temperature model generates updated temperature values 350 for each of the nodes of the motor. Specifically, during step 338, updated motor temperature values are generated for various nodes of the motor, thereby resulting in updated values of a first temperature value 360 for a first node (such as the first node 401 in
After each iteration of step 338, a determination is made as to whether the ignition is still turned on (step 370). This determination is preferably made by the processor 122 of
Accordingly, improved methods, program products, and systems are provided. The improved methods, program products, and systems provide for improved determination of motor temperature values for a vehicle. The methods, program products, and systems provide for potentially improved motor temperature estimates at various nodes of the motor, for example in cases in which the ignition had been turned off for only a short duration of time and/or the ambient temperature is relatively warm.
It will be appreciated that the disclosed methods and systems may vary from those depicted in the Figures and described herein. For example, the controller 120 of
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.
