Method for estimating the temperature of a hydraulic fluid circulated through a hydraulic pump of a gearbox.

Abstract

Procedure that includes: It is determined whether an auto-stop signal (202) is received and whether there is a fault in a transmission control module (70); when the auto-stop signal (202) is received and there is no fault in the transmission control module (70), an auto-stop event of an internal combustion engine (12) is triggered; a maximum line pressure (228) of a hydraulic pump (82) is determined for the auto-stop event; a current quantity is determined (302) which is taken from a current source (19) by the hydraulic pump (82) of a transmission (14) on the basis of a current signal received by a current sensor (86; 260), wherein the current signal indicates the current taken by the hydraulic pump (82); (i) a speed of the hydraulic pump (82) is determined on the basis of a speed signal received from a speed sensor (84) (304), or (ii) an output torque of the hydraulic pump (82) is determined on the basis of the determined current drawn by the hydraulic pump (82) (306), wherein the speed signal indicates a speed of the hydraulic pump (82); a temperature of a hydraulic fluid (120) circulated by the hydraulic pump (82) is estimated on the basis of (i) the determined flow rate drawn by the hydraulic pump (82) and (ii) the determined rotational speed or output torque of the hydraulic pump (82) (308); and a target line pressure of the hydraulic pump (82) is adjusted to the maximum line pressure (228) in order to increase a load on the internal combustion engine (12) through the transmission (14), which includes that the speed of the hydraulic pump (82) is adjusted on the basis of the estimated temperature of the hydraulic fluid (120) (316).

Description

AREA

[0001] The present disclosure relates to vehicle transmissions and, more particularly, to transmission pump control systems. BACKGROUND

[0002] The background description provided herein is intended to provide a general context for the disclosure. The work of the presently named inventors, to the extent described in this background section, as well as aspects of the description not otherwise identified as prior art at the time of filing, are neither explicitly nor implicitly admitted as prior art against the present disclosure.

[0003] An engine generates torque and outputs torque to a transmission. An automatic transmission of a vehicle may include friction coupling elements, such as clutches and gear sets. A control module may engage and disengage the friction coupling elements to establish different gear ratios (also referred to as speed ratios) within the transmission. The transmission may include a hydraulic pump that pumps hydraulic fluid (or transmission fluid) to the friction coupling elements. The hydraulic fluid may be supplied to the friction coupling elements to (i) control operation of the friction coupling elements, and (ii) lubricate and cool transmission components that include some of the friction coupling elements. The hydraulic pump may be an electric pump.

[0004] The document DE 10 2012 204 533 A1 discloses a method for controlling an electric hydraulic fluid pump, in which a time for preparing an operation of the hydraulic fluid pump is reduced by operating the hydraulic fluid pump at a low speed before an operation request in order to exchange hydraulic fluid in fluid lines of the hydraulic fluid pump before it is operated at a second, higher operation preparation speed.

[0005] Document DE 10 2012 000 055 A1 discloses a method for determining the idle state of a hydraulic fluid pump, in which a target speed is set to a higher value than a required speed corresponding to an operating requirement of the hydraulic fluid pump. When controlling the hydraulic fluid pump to the target speed, a phase current of the hydraulic fluid pump is detected, and based on this, it is determined whether the hydraulic fluid pump is idle. SUMMARY

[0006] According to the invention, a method is provided comprising: determining whether an auto-stop signal is received and there is no fault in a transmission control module; if the auto-stop signal is received and there is no fault in the transmission control module, initiating an auto-stop event of an internal combustion engine; determining a maximum line pressure of a hydraulic pump for the auto-stop event; determining an amount of current drawn from a power source by a hydraulic pump of a transmission based on a current signal received from a current sensor, the current signal indicative of the current drawn by the hydraulic pump;and that (i) a speed of the hydraulic pump is determined based on a speed signal received from a speed sensor, or (ii) an output torque of the hydraulic pump is determined based on the amount of current drawn by the hydraulic pump, wherein the speed signal is indicative of the speed of the hydraulic pump. The method further comprises estimating a temperature of a hydraulic fluid circulated through the hydraulic pump based on (i) the amount of current drawn by the hydraulic pump and (ii) the speed or the output torque of the hydraulic pump; adjusting a target line pressure of the hydraulic pump to the maximum line pressure to increase a load on the internal combustion engine through the transmission, which comprises adjusting the speed of the hydraulic pump based on the temperature of the hydraulic fluid.

[0007] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure will be more fully understood from the detailed description and the accompanying drawings, in which: Fig. 1 is a functional block diagram of a vehicle system in accordance with an embodiment of the present disclosure, including a transmission system with a drive power converter module; Fig. 2 is a functional block diagram of the transmission system incorporating the drive power converter module of Fig. 1 contains; Fig. 3 a functional block diagram of a transmission control module and the drive power converter module of Fig. 1 is; Fig. 4 illustrates a method for temperature estimation and hydraulic pump control in accordance with an embodiment of the present disclosure; and Fig. 5 is a plot of current versus temperature in accordance with one embodiment of the present disclosure.

[0009] In the drawings, reference numerals may be reused to designate similar and / or identical elements. DETAILED DESCRIPTION

[0010] An engine generates drive torque for a vehicle. A transmission coupled to the engine transfers torque from the engine to one or more wheels of the vehicle. A transmission hydraulic pump pumps hydraulic fluid from a transmission fluid source (e.g., a sump) to friction coupling elements and transmission components within the transmission and to a torque converter. One or more control valves may control transmission fluid flow to clutches and transmission fluid flow back to the transmission fluid source. A transmission control module (TCM) may control actuation of the control valves.

[0011] A drive power converter module may control the operation of the hydraulic pump based on a temperature of a hydraulic fluid in the hydraulic pump. One or more sensors may be used to detect the temperature of the hydraulic fluid. As an alternative to using the sensors to detect the temperature, the temperature may be estimated based on other information. For example, the temperature may be estimated based on a rotational speed of the hydraulic pump, a torque output of the hydraulic pump, and / or a current drawn by the hydraulic pump. Examples are disclosed below that include estimating temperatures of a hydraulic fluid in a hydraulic pump without the use of a temperature sensor.

[0012] Fig. 1 shows a vehicle system 10 including an internal combustion engine (ICE) 12 that drives a transmission 14 via a torque converter 16. The ICE 12 may be, for example, a spark-ignition engine, a compression-ignition engine, or other suitable engine. The vehicle system 10 may also include one or more electric motors and / or motor / generator devices (sometimes referred to as motor / generator units or MGUs). An exemplary MGU 18 is shown.

[0013] The ICE 12 may output torque to a pump side of the torque converter 16 via an engine output shaft 20, such as a crankshaft. An impeller side of the torque converter 16 may provide torque to the transmission 14 via a transmission input shaft 22. The electric motor(s) and / or MGU(s) may also output torque to the transmission input shaft 22 or to the torque converter 16 to supplement or replace the engine output torque. An MGU may convert mechanical energy to electrical energy, for example, to recharge a power source 19 (e.g., one or more batteries) and / or to provide power to electronic components of a vehicle. The power supplied by the MGU 18 may be provided to a power control module 21 before being applied to the power source 19.

[0014] The transmission 14 contains one or more gear sets (in Fig. 2) for transferring torque between the transmission input shaft 22 and a driveline 26. Each of the gear sets may have a respective gear ratio. A range selector lever 28 allows a user to select an operating mode of the transmission 14. The mode may include, for example, a park mode, a reverse mode, a neutral mode, or one or more forward drive modes. Each operating mode may have a respective gear set and / or a respective gear ratio.

[0015] An engine control module (ECM) 60 controls the ICE 12. For example, the ECM 60 controls starting the ICE 12 and shutting down the ICE 12. The ECM 60 may start the ICE 12 using a starter 62 in response to a user input to start the ICE 12, for example, via an ignition button, switch, or key. The ECM 60 may shut down the ICE 12 in response to a user input, for example, via the ignition button, switch, or key.

[0016] Additionally, the ECM turns off the ICE 12 for auto-stop events, and it starts the ICE 12 for auto-start events, which are performed automatically without the driver requesting that the ICE 12 be turned off or later restarted. An auto-stop event involves turning off the ICE 12 when one or more predetermined activation criteria are met and the driver has not requested that the ICE 12 be turned off (e.g., while the ignition system is in an on state). During an auto-stop event, the ECM 60 turns off the ICE 12 and disables the delivery of fuel to the ICE 12, for example, to increase fuel economy (by reducing fuel consumption). An auto-stop event may be performed, for example, when the vehicle is stopped and a brake pedal is depressed.Auto-stop events may also be performed while the vehicle is moving and the brake pedal is depressed, if the driver has released an accelerator pedal, and / or in other appropriate cases. One or more of the generators may be controlled to apply a torque load to the ICE 12 to bring the ICE 12 to a stop within a predetermined time period during auto-stop events. In other implementations, the ICE 12 may be decelerated to a stop within the predetermined time period during auto-stop events without a torque load from a generator. The ECM 60 and / or another control module (e.g., a hybrid control module) may control starting, shutting down, and fueling for the ICE 12. The ECM 60 and / or the other control module may control operation of one or more of the MGUs and / or one or more electric motors.

[0017] While the ICE 12 is off for an auto-stop event, the ECM 60 may selectively execute an auto-start event when one or more predetermined activation criteria are met. For example, an auto-start event may include activating fuel delivery, enabling the provision of ignition spark, engaging the starter motor with the ICE 12, and applying power to the starter motor to start the ICE 12. For example, the ECM 60 may execute an auto-start event when the driver releases the brake pedal.

[0018] A transmission control module (TCM) 70 controls operation of the transmission 14. Although the TCM 70 is shown implemented within the transmission 14, the TCM 70 may also be implemented external to the transmission 14. The ECM 60 and the TCM 70 may share data using a connection 72, such as an automotive area network (CAN) bus. An example of data that may be shared by the ECM 60 and the TCM 70 is data regarding an auto-stop event of the ICE 12.

[0019] The transmission 14 may also include a traction power converter module / traction rectifier / inverter module (TPIM) 80, a hydraulic pump 82, a speed sensor 84, and a current sensor 86. Although the TPIM 80 is shown separately, it may be assembled with and / or share information with the TCM 70 and / or the ECM 60. The TPIM 80 may be connected to the hydraulic pump 82 via a cable 88 (e.g., a 3-phase cable). The cable 88 may be used to supply alternating current (AC) from the TPIM 80 to the hydraulic pump 82. The TPIM 80 may receive power and / or direct current (DC) from the power source 19 and / or from the power control module 21. The power control module 21 can control whether power is delivered to the TPIM 80 and / or an amount of power (voltage and / or current) delivered to the TPIM 80.The power control module 21 may also be included in the TCM 70 and / or the ECM 60, or it may be separately located as shown. In one implementation, the TPIM 80 receives power directly from the power source 19.

[0020] The TPIM 80 controls operation of the hydraulic pump 82 by providing a control signal CONT to the hydraulic pump 82 via a communication line 90, which indicates a target speed of the hydraulic pump 82, a target output torque (e.g., a torque generated by the hydraulic pump 82 to circulate the hydraulic fluid), and / or one or more target output pressures of the hydraulic pump 82. The target output pressures may refer to output fluid pressures provided to components of the transmission 14 and / or to the torque converter 16. The hydraulic pump 82 is used to circulate hydraulic fluid across the transmission 14 and / or across the torque converter 16 based on the control signal CONT.

[0021] The speed sensor 84 can be used to detect a speed of the hydraulic pump 82 (i.e., a speed of a component of the hydraulic pump 82). The current sensor 86 is used to detect an amount of current drawn by the hydraulic pump 82. Although a single current sensor is shown, multiple current sensors may be included, as shown in Fig. 3. A current sensor may be included for each of the three phases of the hydraulic pump 82, and consequently for each phase of the three-phase cable 88. Each of the current sensors may detect a respective phase of the hydraulic pump 82. In one implementation, only two current sensors are used to detect the current drawn by two of the phases of the hydraulic pump 82. The third undetectable phase, or the amount of current drawn by the third phase, may be determined based on the currents drawn by the other two phases. For example, the third phase may be equal to the negative of a sum of the other two detected currents.

[0022] Fig. 2 shows a transmission system 100 including the transmission 14, the torque converter 16, and the power control module 21. The transmission 14 includes friction coupling elements, such as clutches 104, 106, 108, 110, and 112, and gear sets 114. The transmission 14 may include any number of clutches and gear sets.

[0023] Clutches 104, 106, 108, 110, and 112 control which of the gear sets 114 is engaged with the transmission 14 at any given time. Different gear ratios can be established when various combinations of one or more of the clutches 104, 106, 108, 110, and 112 and gear sets 114 are engaged.

[0024] A transmission fluid (or hydraulic fluid) 120 is communicated to and from the friction coupling elements and may be provided to control engagement and disengagement of the friction coupling elements. A hydraulic pump 82 draws the transmission fluid 120 from a sump 124 or other suitable transmission fluid source. The hydraulic pump 82 pressurizes the transmission fluid 120 and delivers pressurized transmission fluid to a valve body 132. The hydraulic pump 82 may also deliver pressurized transmission fluid to the torque converter 16 and / or one or more components.

[0025] The hydraulic pump 82 may also discharge transmission fluid for lubrication and cooling of one or more transmission components. The transmission fluid 120 may be passed through a transmission cooler (not shown). The transmission cooler transfers heat from the transmission fluid 120 flowing through the transmission fluid cooler to a cooling medium, such as air or a coolant. The hydraulic pump 82 is an electric pump that is (i) driven based on electrical power supplied to the hydraulic pump 82 and (ii) controlled based on the control signal CONT from the TPIM 80. The hydraulic pump 82 may be a variable displacement pump.

[0026] The valve body 132 includes one or more control elements, such as a clutch control solenoid 138, which controls the flow of transmission fluid 120 from the valve body 132 to the friction coupling elements and vice versa. The transmission fluid 120 flows between (i) the valve body 132 and (ii) the friction coupling elements and the torque converter 16 via passages, such as passages formed in a housing 136 of the transmission 14. Although the housing 136 is shown disposed within the transmission 14, the housing 136 may be an outer housing and / or an integral portion of an outer housing of the transmission 14. For example only, the clutch control solenoid 138 may control flow of the transmission fluid 120 between (i) the valve body 132 and (ii) the first clutch 104 via a passage 139.One or more clutch control solenoids and passages may be provided for each of the friction coupling elements and / or for the torque converter 16.

[0027] A regulator valve 140 controls the flow of transmission fluid 120 from the valve body 132 (at a relatively higher pressure) back to the sump 124 (at a relatively lower pressure). By controlling the flow of transmission fluid 120 back to the sump 124, the regulator valve 140 also controls the pressure of transmission fluid 120 input to the control solenoids and the friction coupling elements. By way of example only, the regulator valve 140 controls the pressure of transmission fluid 120 input to the clutch control solenoid 138 and the first clutch 104. The regulator valve 140 may control the pressure of transmission fluid 120 input to all clutch control solenoids. Multiple regulator valves may be included to control the pressure of transmission fluid 120 delivered to portions of one or more of the control solenoids.

[0028] The transmission 14 may include one or more pressure sensors. For example only, a line pressure sensor 160 may measure a pressure of the transmission fluid 120 input to the control solenoids. This pressure is referred to as line pressure. The TCM 70 controls the regulator valve 140 to adjust the line pressure toward a target line pressure. The transmission 14 may include any number of pressure sensors.

[0029] The transmission 14 includes the speed sensor 84 and the current sensor 86. Although one current sensor is shown, additional current sensors may be included as described above. The hydraulic pump 82 receives power from the TPIM 80 via the 3-phase cable 88.

[0030] With reference now to Fig. 1 and Fig. 3, the TCM 70 and the TPIM 80 are shown. The TCM 70 includes: a trigger module 204 that receives an auto-stop signal and an acknowledge signal 208; a timer module 216, a maximum pressure module 224, a target line pressure module 232, and a governor control module 240. The TPIM 80 includes the speed sensor 84, a pump control module 244, and a memory 246.

[0031] The ECM 60 transmits an auto-stop signal 202 to the trigger module 204 for an auto-stop event of the ICE 12. For example, the ECM 60 may transmit the auto-stop signal 202 when the ECM 60 begins shutting down the ICE 12 for an auto-stop event or a predetermined period of time before the ICE 12 begins shutting down for the auto-stop event. The auto-stop signal 202 therefore indicates that the ECM 60 is preparing to shut down the ICE 12 or is in the process of doing so. The ECM 60 may transmit the auto-stop signal 202 for each auto-stop event.

[0032] When the trigger module 204 receives the auto-stop signal 202, the trigger module 204 determines whether transmission assist can be used for the auto-stop. For example, the trigger module 204 may determine that transmission assist can be used if no faults have been diagnosed in the TCM 70. If transmission assist can be used for an auto-stop event, the trigger module 204 may transmit the confirmation signal 208 to the ECM 60 to indicate that the transmission 14 should be used to apply a torque load to the ICE 12 to decelerate the ICE 12 for the auto-stop event. As discussed further below, the transmission 14 increases a torque load on the ICE 12 imposed by the transmission 14 during the auto-stop event.

[0033] The trigger module 204 selectively generates a trigger signal 212 when the auto-stop signal 202 is received. The trigger module 204 may generate the trigger signal 212 after the auto-stop signal 202 is received if one or more criteria are met. For example, the trigger module 204 may reset and start a timer value maintained by the timer module 216 when the auto-stop signal 202 is received. The timer value may maintain a time period since the auto-stop signal 202 was received. The trigger module 204 may generate the trigger signal 212 when the timer value becomes greater than a predetermined value. In other words, the trigger module 204 may generate the trigger signal 212 a predetermined time period (equal to the predetermined value) after the auto-stop signal 202 is received.Additionally or alternatively, the trigger module 204 may generate the trigger signal 212 when an engine speed 220 becomes less than a predetermined speed after receiving the auto-stop signal 202. The engine speed 220 is measured, for example, based on positions of a crankshaft of the ICE 12, which may be measured using a crankshaft position sensor (not shown). The engine speed 220 may be provided by the ECM 60 to the modules 220, 224.

[0034] When the trigger signal 212 is generated, the maximum pressure module 224 determines a maximum line pressure 228 for the auto-stop event. The maximum line pressure 228 corresponds to a maximum value of the line pressure for the auto-stop event. In other words, the maximum line pressure 228 corresponds to a maximum value of the pressure of the transmission fluid 120 output by the regulator valve 140 to the control solenoids for the auto-stop event.

[0035] The maximum line pressure 228 may be a fixed, predetermined pressure or a variable pressure. In the case where the maximum line pressure 228 is variable, the maximum pressure module 224 may determine the maximum line pressure 228 based, for example, on the engine speed 220 when the auto-stop signal 202 is generated. The maximum pressure module 224 may determine the maximum line pressure 228 using, for example, a function or a map that relates engine speeds to maximum line pressures. The maximum line pressure 228 may decrease as the engine speed 220 decreases and vice versa.

[0036] The target line pressure module 232 sets a target line pressure 236. A regulator control module 240 controls the regulator valve 140 to achieve the target line pressure 236. The regulator control module 240 may control the regulator valve 140 in a closed-loop manner and based on a line pressure 242. The line pressure 242 may be detected using the line pressure sensor 160. Although the line pressure sensor 160 is shown detecting a return line pressure, the line pressure sensor 160 may also detect a supply line pressure from the hydraulic pump 82. The pump control module 244 may control an output of the hydraulic pump 82 to achieve the target line pressure 236. For example, the pump control module 244 may increase a displacement, a speed, and / or an output torque of the hydraulic pump 82 as the target line pressure 236 increases.

[0037] The target line pressure module 232 may set the target line pressure 236 based on one or more operating parameters, such as: the speed and / or output torque of the hydraulic pump 82; a temperature of the hydraulic fluid circulated through and / or within the hydraulic pump 82; and / or other parameters. This information may be provided by the TPIM 80 and / or the pump control module 244. When the trigger signal 212 is generated, the target line pressure module 232 increases the target line pressure 236 to the maximum line pressure 228. For example, the target line pressure module 232 may ramp the target line pressure 236 to the maximum line pressure 228 at a predetermined rate or increase the target line pressure 236 to the maximum line pressure 228 in another suitable manner.

[0038] When the target line pressure 236 increases, the regulator control module 240 may close the regulator valve 140 to limit transmission fluid flow through the regulator valve 140 back to the sump 124. Limiting fluid flow through the regulator valve 140 back to the sump 124 increases the pressure of the transmission fluid 120 applied to one or more of the control elements, thereby increasing a torque load imposed on the ICE 12 by the transmission 14. In particular, limiting fluid flow through the regulator valve 140 increases the backpressure at the hydraulic pump 82 and increases the torque load imposed on the ICE 12 by the hydraulic pump 82.

[0039] This increased torque load on the ICE 12 can help slow the ICE 12 to a stop sooner during the auto-stop event than if the torque load were not increased. Additionally, the transmission 14 dampens vibrations perceived when the ICE 12 is deactivated for the auto-stop event, thereby reducing noise, vibration, and / or harshness perceived in a vehicle's passenger compartment.

[0040] One or more electrical generators, such as an alternator or the MGU 18, may be controlled during auto-stop events to apply a torque load to the ICE 12 and to stop the ICE 12 within a predetermined period of time after auto-stop events begin. When the transmission 14 imposes a torque load on the ICE 12 during auto-stop events, a lower output electrical generator (e.g., an alternator or MGU) may be implemented because the reliance on the electrical generator to decelerate the ICE 12 during auto-stop events is reduced.

[0041] Additionally, applying a torque load to the ICE 12 during auto-stop events using the transmission 14 heats the transmission fluid 120. This heating causes the transmission fluid 120 to be warmer than it would otherwise be the next time the ICE 12 is started following an auto-start event. Friction losses attributable to the transmission fluid 120 during the next auto-start event may therefore be lower due to the heating, which may provide an increase in fuel efficiency. The target rail pressure module 232 may decrease the target rail pressure 236 from the maximum rail pressure 228, for example, once the engine speed 220 reaches zero during the auto-stop event.

[0042] The pump control module 244 may include a current module 250, a temperature module 252, and a speed and / or torque module 254. The current module 250 may measure current draw signals CUR M1 , CURM2 , CUR M3received from respective current sensors 260, 262, 264. The current signals indicate amounts of current drawn by respective phases of the hydraulic pump 82. The temperature module 252 estimates a temperature of the hydraulic fluid circulated through and / or within the hydraulic pump 82. Although the temperature module 252 is described herein as estimating a temperature of the hydraulic fluid circulated through and / or within the hydraulic pump 82, the temperature module 252 may alternatively or additionally estimate a temperature of a component of the hydraulic pump 82 and / or an average temperature of the hydraulic pump 82 as a whole. A viscosity of the hydraulic fluid within the hydraulic pump 82 is related to the temperature of the hydraulic fluid. The viscosity is also related to the flow drawn by the hydraulic pump 82.As a result, and as further described below, the temperature of the hydraulic fluid may be estimated based on the current drawn by the hydraulic pump 82. The speed / torque module 254 monitors an output (e.g., a speed signal SPD). M ) of the speed sensor 84. The speed signal SPD M indicates a speed of a component of the hydraulic pump 82.

[0043] The operation of the TPIM 80 is described below with reference to the procedure of Fig. 4. The systems disclosed herein may be operated using numerous methods, with an exemplary method being shown in Fig. 4 is shown. In Fig. 4 shows a method for temperature estimation and hydraulic pump control. Although the following tasks are primarily related to the implementations of Fig. 1-3, the tasks can be easily modified to suit other implementations of the present disclosure. The tasks can be performed iteratively.

[0044] The method may begin at 300. At 302, the power module 250 determines amounts of power drawn by one or more phases of the hydraulic pump 82. This may include determining the current signals CUR M1 , CUR M2 , CUR M3 are received and that a current draw signal CURDRW is generated based on these signals. The current draw signal CURDRW can indicate: a total amount of current drawn by the hydraulic pump 82; the amounts of current drawn by one or more phases of the hydraulic pump 82; an average amount of current drawn by the phases of the hydraulic pump 82; and / or other values ​​indicating amounts of current drawn by the hydraulic pump 82.

[0045] At 304, the speed sensor 84 can detect the speed signal SPD M which may indicate a speed of the hydraulic pump 82. At 306, the speed / torque module 254 may determine a magnitude of an output torque of the hydraulic pump 82 (e.g., torque generated by the hydraulic pump 82 to circulate the hydraulic fluid). The current drawn by the hydraulic pump 82 is proportional to the output torque of the hydraulic pump 82. The output torque may be determined based on the current draw signal CURDRW. Task 304 and / or task 306 may not be required to be performed.

[0046] At 308, the temperature module 252 estimates a temperature of the hydraulic fluid circulated through and / or within the hydraulic pump 82, as described above. The temperature module 252 may estimate the temperature based on previously generated tables 309, profiles 311, functions, control algorithms, and / or polynomial equations that relate a temperature of the hydraulic fluid to: one or more amounts of flow drawn by the hydraulic pump 82; a speed of the hydraulic pump 82; and / or an output torque of the hydraulic pump 82. The temperature is estimated based on a predetermined relationship between (i) the temperature of the hydraulic fluid, (ii) the flow drawn by the hydraulic pump 82, and (iii) the speed and / or the output torque of the hydraulic pump 82.The current drawn by hydraulic pump 82 is a function of the viscosity of a hydraulic fluid within hydraulic pump 82. The viscosity of hydraulic pump 82 is a function of the temperature of the hydraulic fluid within hydraulic pump 82. As the temperature of the hydraulic fluid decreases, the viscosity of the hydraulic fluid increases. For a given speed of hydraulic pump 82, the amount of current drawn by hydraulic pump 82 increases as the viscosity of the hydraulic fluid increases.

[0047] Tables 309 and profiles 311 may be stored in memory 246 and accessible by temperature module 252. Values ​​of tables 309 may be predetermined by collecting a range of speed and current data for hydraulic pump 82. Alternatively, the data may be a result of operating hydraulic pump 82 on a dynamometer at various temperatures. This data may be used to provide one or more of profiles 311. As an example, the profiles may include plots of current drawn versus temperature for respective speeds of hydraulic pump 82. Fig.5 shows example profiles 313A-E. Each of the profiles 313A-E (or each of the curves shown) is for a respective operating speed of the hydraulic pump 82. Each of the profiles 313A-E may be provided for one or more phases of the hydraulic pump 82. For a particular speed and / or output torque, a profile may be provided for each phase or for the phases collectively (e.g., an average or total amount of current drawn by the phases). The unit of measurement for the operating speed of the hydraulic pump 82 may be revolutions per minute (RPM). As an example, the profiles 313A-E shown may be directed to operating speeds of 100 RPM, 500 RPM, 1000 RPM, 1500 RPM, 2000 RPM, respectively. Any number of profiles may be used. One or more third-order polynomials can be derived based on the data in Tables 309 and / or Profiles 311.

[0048] At 310, the speed / torque module 254 may compare the temperature to a predetermined temperature. The predetermined temperature may be determined based on the speed of the hydraulic pump 82, the output torque of the hydraulic pump 82, and / or the one or more amounts of current drawn by the hydraulic pump 82. For example, the predetermined temperature may be increased as the speed of the hydraulic pump 82 increases. As another example, the predetermined temperature may be increased as the output torque and / or the amount of current drawn by the hydraulic pump increases. In one implementation, the predetermined temperature is a fixed value independent of the speed, output torque, and / or current drawn by the hydraulic pump 82.If the temperature of the hydraulic pump 82 is less than or equal to the predetermined temperature, task 312 may be performed; otherwise, task 316 may be performed.

[0049] At 312, the speed / torque module 254 may compare the speed of the hydraulic pump 82 to a predetermined speed and / or the output torque of the hydraulic pump 82 to a predetermined output torque. If the speed of the hydraulic pump 82 is greater than or equal to the predetermined speed and / or the output torque of the hydraulic pump 82 is greater than or equal to the predetermined output torque, then task 314 may be performed; otherwise, task 316 may be performed.

[0050] Tasks 310 and 312 may be performed to prevent degradation of the hydraulic pump. Tasks 310 and 312 may be performed to prevent the hydraulic pump from operating at excessive speed when the temperature is lower than the predetermined temperature and the fluid viscosity is high. Tasks 310 and 312 may be performed to prevent the hydraulic pump from generating too much output torque and / or drawing too much current when the temperature is lower than the predetermined temperature.

[0051] At 314, the speed / torque module 254 generates the control signal CONT to decrease the speed and / or the output torque of the hydraulic pump 82. The resulting speed of the hydraulic pump 82 may be less than a predetermined target speed and / or the resulting output torque of the hydraulic pump 82 may be less than a predetermined target output torque of the hydraulic pump 82. This may include turning off the hydraulic pump 82. This limits the speed and output torque of the hydraulic pump 82. Task 302 may be performed following task 314.

[0052] At 316, the speed / torque module 254 adjusts the speed and / or output torque of the hydraulic pump 82 based on the hydraulic fluid temperature, the target line pressure, a target output torque of the hydraulic pump 82, and / or a target speed of the hydraulic pump 82. For example, the speed and / or output torque of the hydraulic pump 82 may be increased as the hydraulic fluid temperature increases. A pump speed that achieves a target fluid pressure is adjusted based on the estimated temperature.

[0053] The tasks described above are intended as illustrative examples; the tasks may be executed sequentially, synchronously, concurrently, continuously, during overlapping time periods, or in a different order depending on the application. Furthermore, depending on the implementation and / or the order of events, any of the tasks may not be executed or may be skipped.

[0054] The examples described above eliminate the need for one or more temperature sensors and corresponding hardware and / or software. The software may include processor control and diagnostic software and / or signal processing software corresponding to the temperature sensors.

[0055] The foregoing description is merely exemplary and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure may be implemented in a variety of forms. Therefore, while this disclosure contains specific examples, the actual scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. The term A, B, and / or C, as used herein, should be construed to mean a logical (A OR B OR C) using a non-exclusive logical OR, and should not be construed to mean at least one of A, at least one of B, and at least one of C.It should be understood that one or more steps in a method may be performed in a different order (or simultaneously) without altering the principles of the present disclosure.

[0056] Throughout this application, including the definitions below, the term "module" or the term "controller" may be replaced by the term "circuit." The term "module" may refer to, be part of, or include an application-specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field-programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; or other suitable hardware components that provide the described functionality; or a combination of some or all of the foregoing, such as in a system-on-chip.

[0057] The module may include one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces connected to a local area network (LAN), the Internet, a wide area network (WAN), or combinations thereof. The functionality of any given module of the present disclosure may be distributed among multiple modules interconnected via interface circuits. For example, multiple modules may enable load balancing. In another example, a server module (also known as a remote or cloud module) may perform a particular functionality on behalf of a client module.

[0058] The term code, as used above, may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, data structures, and / or objects. The term shared processor circuitry includes a single processor circuit that executes some or all of the code from multiple modules. The term group processor circuitry includes a processor circuit that, in combination with additional processor circuitry, executes some or all of the code from one or more modules. References to multiple processor circuits include multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the foregoing.The term shared memory circuit refers to a single memory circuit that stores some or all of the code from multiple modules. The term group memory circuit refers to a memory circuit that, in combination with additional memories, stores some or all of the code from one or more modules.

[0059] The term "memory circuit" is a subset of the term "computer-readable medium." As used herein, the term "computer-readable medium" encompasses non-transient electrical or electromagnetic signals propagating through a medium (such as a carrier wave); therefore, the term "computer-readable medium" can be understood as tangible and non-transient.Examples, without limitation, of a non-transitory tangible computer-readable medium include non-volatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray disc).

[0060] The devices and methods described in this application may be implemented partially or entirely by a special-purpose computer created by configuring a general-purpose computer to perform one or more specific functions embodied in computer programs. The functional blocks and flowchart elements described above serve as software descriptions that can be translated into computer programs through the routine work of a person skilled in the art or a programmer.

[0061] The computer programs contain processor-executable instructions stored on at least one non-transitory, tangible, computer-readable medium. The computer programs may also contain or rely on stored data. The computer programs may include a basic input / output system (BIOS) that interacts with the hardware of the special-purpose computer, device drivers that interact with specialized devices of the special-purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0062] The computer programs may contain: (i) a descriptive text to be parsed, such as HTML (Hypertext Markup Language) or XML (Extensible Markup Language), (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. By way of example only, source code may be written using a syntax of languages ​​including C, C++, C#, Objective C, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5, Ada, ASP (Active Server Pages), PHP, Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua and Python®.

[0063] None of the elements recited in the claims are intended to be a means-plus-function element within the meaning of 35 USC § 112(f) unless an element is expressly recited using the phrase "means for" or, in the case of a method claim, using the phrases "operation for" or "step for."

Claims

[1] Procedure which includes: determining whether an auto-stop signal (202) is received and there is no fault in a transmission control module (70); when the auto-stop signal (202) is received and there is no fault in the transmission control module (70), an auto-stop event of an internal combustion engine (12) is triggered; a maximum line pressure (228) of a hydraulic pump (82) is determined for the auto-stop event; determining (302) an amount of current drawn from a current source (19) by the hydraulic pump (82) of a transmission (14) based on a current signal received from a current sensor (86; 260), the current signal indicating the current drawn by the hydraulic pump (82); (i) a speed of the hydraulic pump (82) is determined (304) based on a speed signal received from a speed sensor (84), or (ii) an output torque of the hydraulic pump (82) is determined (306) based on the determined amount of current drawn by the hydraulic pump (82), wherein the speed signal indicates a speed of the hydraulic pump (82); a temperature of a hydraulic fluid (120) circulated through the hydraulic pump (82) is estimated (308) based on (i) the determined amount of current drawn by the hydraulic pump (82) and (ii) the determined speed or output torque of the hydraulic pump (82); and a target line pressure of the hydraulic pump (82) is adjusted to the maximum line pressure (228) to increase a load on the internal combustion engine (12) through the transmission (14), which comprises the speed of the hydraulic pump (82) is adjusted (316) based on the estimated temperature of the hydraulic fluid (120). [2] The method of claim 1, further comprising: Direct current is supplied via the power source (19); the direct current is converted into alternating current; and at least a portion of the alternating current is drawn via the hydraulic pump (82), wherein the determined amount of current drawn by the hydraulic pump (82) contains the at least a portion of the alternating current. [3] The method of claim 1, further comprising: a 3-phase alternating current is received at the hydraulic pump (82); the current sensor (86; 260) detects an amount of current supplied to a first phase of the hydraulic pump (82); and a third sensor (262, 264) detects an amount of current supplied to a second phase of the hydraulic pump (82); wherein the amount of current drawn by the hydraulic pump (82) comprises the amount of current supplied to the first phase and the amount of current supplied to the second phase. [4] The method of claim 3, further comprising generating a second current signal, wherein: the second current signal indicates the amount of current supplied to the first phase and the amount of current supplied to the second phase; and the temperature of the hydraulic fluid (120) is estimated based on the second current signal. [5] The method of claim 1, wherein the amount of current drawn by the hydraulic pump (82) is an amount of current drawn by a single phase of the hydraulic pump (82). [6] The method of claim 1, wherein the amount of current drawn by the hydraulic pump (82) is an amount of current drawn by at least two phases of the hydraulic pump (82). [7] A method according to claim 1, comprising: the speed of the hydraulic pump (82) is determined on the basis of the speed signal received from the speed sensor (84); and the temperature of the hydraulic fluid (120) is estimated (308) based on the speed of the hydraulic pump (82). [8] A method according to claim 1, comprising: the output torque of the hydraulic pump (82) is determined based on the amount of current drawn by the hydraulic pump (82); and the temperature of the hydraulic fluid (120) is estimated (308) based on the output torque of the hydraulic pump (82). [9] The method of claim 1, further comprising selecting one of a plurality of temperature profiles (311; 313A-E) based on the speed or output torque of the hydraulic pump (82), wherein: each of the plurality of temperature profiles (311; 313A-E) provides a current-to-temperature relationship for a respective speed or for a respective output torque of the hydraulic pump (82); and the temperature of the hydraulic fluid (120) is estimated (308) based on the selected profile from the plurality of temperature profiles (311; 313A-E).

Images