Temperature estimation system, vehicle, and temperature estimation method

Abstract

This system uses a simple configuration to accurately estimate the temperature of fluids flowing through components installed in a real machine. [Solution] The temperature estimation system 1 includes a temperature sensor 10 that measures the temperature of the hydraulic fluid W flowing through a reduction gear 51 mounted on a vehicle 50 as the measured temperature, a solenoid valve 20 for actual use arranged in a flow path 52 through which the hydraulic fluid W flows, and an estimation device 30 that estimates the temperature of the hydraulic fluid W as the estimated temperature T based on the electrical resistance Ω related to the solenoid valve 20 for actual use. The estimation device 30 stores a relational expression E for converting the electrical resistance Ω(T) related to a reference solenoid valve 60, which is different from the solenoid valve 20 for actual use, into the estimated temperature T, as a reference relational expression Es. The estimation device 30 corrects the reference relational expression Es to a correction relational expression Ec based on the electrical resistance Ωm related to the solenoid valve 20 for actual use and the measured temperature tm measured by the temperature sensor 10.

Description

[Technical Field]

[0001] This disclosure relates to a temperature estimation system and vehicle, as well as a temperature estimation method. [Background technology]

[0002] A temperature estimation device is known for estimating the temperature of the hydraulic fluid flowing through a transmission. For example, in Patent Document 1, the transmission is equipped with a solenoid valve in an environment that is in contact with the hydraulic fluid. The temperature estimation device obtains a resistance value based on the voltage applied to the coil of the solenoid valve and the current flowing through the coil, and calculates the temperature of the hydraulic fluid based on the resistance value. The temperature of the hydraulic fluid can be estimated using a solenoid valve mounted on a transmission. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2004-316848 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In this type of temperature estimation device, in addition to measuring the temperature of the transmission's hydraulic fluid with a temperature sensor, the device estimates the hydraulic fluid temperature based on the electrical resistance of a solenoid valve placed in the hydraulic fluid flow path, which correlates with the hydraulic fluid temperature. Based on the estimated temperature calculated by the temperature estimation device, the validity of the measured temperature measured by the temperature sensor can be determined, and furthermore, fault diagnosis of the temperature sensor can be performed.

[0005] Incidentally, in this type of temperature estimation device, a relational equation is generated during development before mass production of the vehicle to convert the electrical resistance of a reference solenoid valve into an estimated temperature. In each mass-produced vehicle, the temperature estimation device uses the above relational equation generated during development to estimate the temperature of the hydraulic fluid as an estimated temperature based on the electrical resistance of the solenoid valve used in the actual vehicle's reduction gear.

[0006] However, the relationship between the electrical resistance of the solenoid valve and the actual temperature of the hydraulic fluid varies from vehicle to vehicle (and more specifically, from solenoid valve to solenoid valve), so if the relationship generated during development is used as is, the temperature estimation device will not be able to accurately estimate the temperature of the hydraulic fluid.

[0007] One possible approach is to continuously monitor the estimated temperature of the hydraulic fluid, calculated by a temperature estimation device, and the measured temperature of the hydraulic fluid, measured by a temperature sensor, while the vehicle is in motion, and then use a map to resolve the difference between the two. However, this would complicate the calculations and control processes.

[0008] This challenge can also be applied to actual machines other than vehicles, mounted components other than speed reducers, flow path members other than solenoid valves, fluids other than hydraulic fluid, and indicators other than electrical resistance.

[0009] The purpose of this disclosure is to accurately estimate the temperature of the fluid flowing through the components mounted on an actual machine using a simple configuration. [Means for solving the problem]

[0010] The temperature estimation system according to this disclosure comprises a temperature sensor that measures the temperature of a fluid flowing through mounted components mounted on an actual machine as the measured temperature, a flow channel component for the actual machine arranged in the flow channel through which the fluid flows, and an estimation device that estimates the temperature of the fluid as the estimated temperature based on a first index related to the flow channel component for the actual machine. The estimation device stores a relational expression for converting the first index related to a reference flow channel component different from the flow channel component for the actual machine into the estimated temperature as a reference relational expression, and the estimation device corrects the reference relational expression into a correction relational expression based on the first index related to the flow channel component for the actual machine and the measured temperature measured by the temperature sensor.

[0011] When converting the first index related to the in-machine flow path component to the estimated temperature of the fluid, if the reference relational expression obtained from the reference flow path component is used as it is, the variation factors of the in-machine flow path component cannot be reflected, so the temperature of the fluid flowing through the components mounted on the in-machine cannot be accurately estimated.

[0012] Therefore, based on the first index related to the in-machine flow path component and the measured temperature of the fluid measured by the temperature sensor, the reference relational expression is corrected to a correction relational expression.

[0013] When converting the first index related to the in-machine flow path component to the estimated temperature of the fluid, by using the correction relational expression, the variation factors of the in-machine flow path component can be reflected, and the temperature of the fluid flowing through the components mounted on the in-machine can be accurately estimated as the estimated temperature.

[0014] As described above, with a simple configuration, the temperature of the fluid flowing through the components mounted on the in-machine can be accurately estimated.

[0015] In one embodiment, the in-machine flow path component is an in-machine solenoid valve, the reference flow path component is a reference solenoid valve, and the first index is electrical resistance.

[0016] When converting the electrical resistance related to the in-machine solenoid valve to the estimated temperature of the fluid, if the reference relational expression obtained from the reference solenoid valve is used as it is, the variation factors of the in-machine solenoid valve cannot be reflected, so the temperature of the fluid flowing through the components mounted on the in-machine cannot be accurately estimated.

[0017] Therefore, based on the electrical resistance related to the in-machine solenoid valve and the measured temperature of the fluid measured by the temperature sensor, the reference relational expression is corrected to a correction relational expression.

[0018] When converting the electrical resistance related to the in-machine solenoid valve to the estimated temperature of the fluid, by using the correction relational expression, the variation factors of the in-machine solenoid valve can be reflected, and the temperature of the fluid flowing through the components mounted on the in-machine can be accurately estimated as the estimated temperature.

[0019] In one embodiment, the reference relational expression is represented by a linear equation having the electrical resistance and the estimated temperature as variables.

[0020] The reference relational expression can be simply represented.

[0021] In one embodiment, the reference relational expression is represented as Ω(T)=Ω(t)×{α×(T−t)+1}, and the correction relational expression is represented as Ω(T)=Ω(t)’×{α×(T−t)+1}, where T is a variable representing the estimated temperature, Ω(T) is a variable that is a function of T and represents the electrical resistance, t is a constant representing a specific estimated temperature, Ω(t) is a constant representing a specific electrical resistance related to the reference solenoid valve when the estimated temperature is t, Ω(t)’ is a constant representing a specific electrical resistance related to the solenoid valve for the actual machine when the estimated temperature is t, and α is a constant.

[0022] The reference relational expression and the correction relational expression can be simply represented.

[0023] In one embodiment, in the unknown correction relational expression, the estimation device substitutes the measured temperature measured by the temperature sensor for T and substitutes the electrical resistance related to the solenoid valve for the actual machine for Ω(T), thereby obtaining Ω(t)’.

[0024] By obtaining Ω(t)’, the reference relational expression can be corrected to the correction relational expression.

[0025] In one embodiment, the estimation device repeats the calculation for obtaining Ω(t)’ a predetermined number of times under different conditions to learn Ω(t)’.

[0026] The reliability of Ω(t)’ can be improved, and as a result, the reliability of the correction relational expression can be improved.

[0027] In one embodiment, after Ω(t)’ is determined, the estimation device does not perform the calculation for obtaining Ω(t)’.

[0028] Since the correction relation that is determined along with the determination of Ω(t)' is used without modification, the calculation of converting from electrical resistance to estimated temperature can be simplified.

[0029] In one embodiment, the estimation device corrects the reference relation to the correction relation based on the electrical resistance and the measured temperature obtained after a predetermined time has elapsed since the fluid flow to the mounted component was stopped.

[0030] Since the estimated temperature derived from electrical resistance and the measured temperature measured by the temperature sensor are almost the same, the correction relation can be determined with high accuracy.

[0031] In one embodiment, the temperature estimation system includes a current sensor for measuring the current flowing through the solenoid valve for the actual machine, the estimation device drives the solenoid valve for the actual machine by applying a voltage to the solenoid valve for the actual machine, and the estimation device calculates the electrical resistance based on the voltage and the current.

[0032] Electrical resistance can be easily calculated.

[0033] In one embodiment, the actual machine is a vehicle, the mounted component is a speed reducer, and the fluid is hydraulic oil for operating the speed reducer.

[0034] With a simple configuration, the temperature of the hydraulic fluid flowing through a vehicle's speed reducer can be accurately estimated.

[0035] The vehicle relating to this disclosure comprises the reduction gear and the temperature estimation system.

[0036] The temperature estimation method according to this disclosure measures the temperature of a fluid flowing through mounted components installed in an actual machine as the measured temperature, estimates the temperature of the fluid as the estimated temperature based on a first index relating to a flow channel component for the actual machine placed in the flow path through which the fluid flows, stores a relational expression for converting the first index relating to a reference flow channel component different from the actual machine flow channel component to the estimated temperature as a reference relational expression, and corrects the reference relational expression to a correction relational expression based on the first index relating to the actual machine flow channel component and the measured temperature. [Effects of the Invention]

[0037] According to this disclosure, the temperature of the fluid flowing through the components mounted on the actual device can be accurately estimated with a simple configuration. [Brief explanation of the drawing]

[0038] [Figure 1] Figure 1 shows a vehicle equipped with a temperature estimation system according to the first embodiment. [Figure 2] Figure 2 shows the temperature estimation system according to the first embodiment. [Figure 3] Figure 3 shows a block diagram of the temperature estimation system according to the first embodiment. [Figure 4] Figure 4 shows the reference relational expression according to the first embodiment. [Figure 5] Figure 5 shows the correction from the reference relation to the correction relation according to the first embodiment. [Figure 6] Figure 6 shows a flowchart according to the first embodiment. [Figure 7] Figure 7 shows a flowchart according to the second embodiment. [Modes for carrying out the invention]

[0039] The embodiments of this disclosure will be described in detail below with reference to the drawings. The following description of preferred embodiments is illustrative in nature and is not intended to limit the disclosure, its applications or uses in any way.

[0040] <First Embodiment> The first embodiment will be described.

[0041] (vehicle) Figure 1 shows a vehicle 50 equipped with a temperature estimation system 1. Vehicle 50 is an example of a real machine. Vehicle 50 is a mass-produced vehicle. Vehicle 50 is equipped with a reduction gear 51 and a temperature estimation system 1.

[0042] The reduction gear 51 is mounted on the vehicle 50. The reduction gear 51 is an example of a mounted component. The reduction gear 51 is an automatic reduction gear. The reduction gear 51 is mounted, for example, in the engine compartment at the front of the vehicle 50, together with the engine (not shown). The input shaft of the reduction gear 51 is connected to the output shaft of the engine. The rotation of the engine is reduced by the reduction gear 51 before being transmitted to the wheels. A motor may be used together with the engine, or instead of the engine.

[0043] A flow path 52 is connected to the gearbox 51. Hydraulic fluid W flows through the flow path 52. Hydraulic fluid W is an example of a fluid. The flow path 52 is a hydraulic fluid line.

[0044] The reduction gear 51 receives hydraulic fluid W from the flow path 52. The hydraulic fluid W is there to operate the reduction gear 51. The hydraulic fluid W controls the hydraulic pressure on the clutch inside the reduction gear 51, thereby operating the reduction gear 51. The hydraulic fluid W is sent to the flow path 52 by a pump (not shown), flows through the flow path 52 to the reduction gear 51, and then returns to the pump.

[0045] The temperature estimation system 1 is mounted on the vehicle 50. The temperature estimation system 1 comprises a temperature sensor 10, a solenoid valve 20 for actual use, an estimation device 30, and a current sensor 40.

[0046] The temperature sensor 10 is mounted on the vehicle 50. The temperature sensor 10 is located in the flow path 52. The temperature sensor 10 measures the temperature of the hydraulic fluid W flowing through the reduction gear 51 as the measured temperature. It is preferable that the temperature sensor 10 be located as close as possible to the reduction gear 51. The temperature sensor 10 may be a known thermometer.

[0047] The solenoid valve 20 for the actual machine is mounted on the vehicle 50. The solenoid valve 20 for the actual machine is positioned in the passage 52 through which the hydraulic fluid W flows. The solenoid valve 20 for the actual machine is an example of a passage component for the actual machine. In this example, seven solenoid valves 20 for the actual machine are provided. The solenoid valve 20 for the actual machine is a type of electromagnetic valve. The solenoid valve 20 for the actual machine opens and closes the flow of hydraulic fluid W to the reduction gear 51, and adjusts the flow rate of hydraulic fluid W to the reduction gear 51. Details of the solenoid valve 20 for the actual machine will be described later.

[0048] The estimation device 30 is mounted on the vehicle 50. The estimation device 30 is, for example, a TCM (Transmission Control Module). The estimation device 30 consists of hardware such as a processor, memory, and interface, and software such as a database and control program. The estimation device 30 is electrically connected to the temperature sensor 10, the actual solenoid valve 20, and the current sensor 40 by wire or wireless means. Details of the estimation device 30 will be described later.

[0049] The current sensor 40 is mounted on the vehicle 50. The current sensor 40 will be described later.

[0050] (Temperature estimation system) Figure 2 shows the temperature estimation system 1. Figure 3 shows a block diagram of the temperature estimation system 1. The estimation device 30 is electrically connected to the solenoid valve 20 for the actual machine. The estimation device 30 and the solenoid valve 20 for the actual machine constitute a circuit.

[0051] The actual solenoid valve 20 has a solenoid section 21 and a valve section 22. The solenoid section 21 converts electrical energy into mechanical motion. The solenoid section 21 is provided with a coil 21a. Both ends (one end and the other end) of the coil 21a are connected to the estimation device 30. The valve section 22 opens and closes the flow of the hydraulic fluid W. In this example, the valve section 22 is of the spool type. In the spool type, the valve section 22 includes a cylindrical tube 22a and a skewer-shaped valve body 22b arranged inside the tube 22a. The electromagnetic force from the coil 21a of the solenoid section 21 causes the valve body 22b to move inside the tube 22a in the valve section 22. This opens and closes the flow of the hydraulic fluid W.

[0052] The estimation device 30 includes a processor 31. The processor 31 includes a valve drive unit 31a, a resistance calculation unit 31b, a temperature estimation unit 31c, a fault diagnosis unit 31d, and a learning unit 31e. The estimation device 30 also includes a memory 32. The memory 32 stores the relational expression E.

[0053] The estimation device 30 is electrically connected to one end and the other end of the coil 21a of the actual solenoid valve 20. The estimation device 30 drives the actual solenoid valve 20 by applying a voltage V to the actual solenoid valve 20. In detail, the valve drive unit 31a of the estimation device 30 drives the valve body 22b of the valve unit 22 in the actual solenoid valve 20 by applying a voltage V to the coil 21a of the solenoid unit 21 in the actual solenoid valve 20. The unit of voltage V is [V].

[0054] In practice, the valve drive unit 31a of the estimation device 30 applies a voltage V to the coil 21a of the actual solenoid valve 20 at a predetermined duty cycle [%]. If the set value of the duty cycle is known, the value of the applied voltage V can also be determined.

[0055] The current sensor 40 is positioned between the actual solenoid valve 20 and the estimation device 30. The current sensor 40 is electrically connected to the other end of the coil 21a of the actual solenoid valve 20. The current sensor 40 is electrically connected to the estimation device 30. The current sensor 40 may be a known ammeter. The current sensor 40 measures the current A flowing through the coil 21a of the actual solenoid valve 20. The unit of current A is [A].

[0056] The resistance calculation unit 31b of the estimation device 30 calculates the electrical resistance Ω based on the voltage V and current A. Electrical resistance Ω is an example of a first indicator. The unit of electrical resistance Ω is [Ω]. Electrical resistance Ω is obtained by dividing the voltage V by the current A (Ω = V / A).

[0057] The memory 32 of the estimation device 30 stores the relational equation E. As will be described in detail later, in relational equation E, there is a correlation between the temperature of the hydraulic fluid W and the electrical resistance Ω related to the solenoid valve 20 for the actual machine.

[0058] The temperature estimation unit 31c of the estimation device 30 estimates the temperature of the hydraulic fluid W as the estimated temperature based on the electrical resistance Ω related to the solenoid valve 20 for the actual machine, using the relational expression E stored in the memory 32.

[0059] The estimation device 30 is electrically connected to the temperature sensor 10. The fault diagnosis unit 31d of the estimation device 30 diagnoses a fault in the temperature sensor 10 based on the estimated temperature of the hydraulic fluid W estimated by the temperature estimation unit 31c of the estimation device 30 and the measured temperature of the hydraulic fluid W measured by the temperature sensor 10. For example, if the difference between the estimated temperature and the measured temperature is greater than a threshold, it is determined that the temperature sensor 10 is faulty.

[0060] The learning unit 31e of the estimation device 30 will be described later.

[0061] (Reference relation) Figure 4 shows the reference relation Es. The memory 32 of the estimation device 30 stores the relation E used to convert the electrical resistance Ω related to the reference solenoid valve 60 into the estimated temperature T as the reference relation Es, before the vehicle 50 is shipped. The reference solenoid valve 60 is an example of a reference flow path component. The unit of the estimated temperature T is [°C]. The reference solenoid valve 60 is the master unit.

[0062] The reference solenoid valve 60 was used during the development of the vehicle 50 before mass production, and is not installed in the actual vehicle 50 (actual unit) supplied to the market. The reference solenoid valve 60 is different from the actual unit solenoid valve 20. The actual vehicle 50 (actual unit) is equipped with the actual unit solenoid valve 20, not the reference solenoid valve 60.

[0063] In Figure 4, the horizontal axis represents the estimated temperature T, and the vertical axis represents the electrical resistance Ω. During development, experiments are conducted using multiple reference solenoid valves 60 of the same specifications. Although each of the multiple reference solenoid valves 60 has the same specifications, there are always variations (individual differences) due to manufacturing tolerances in the hardware configuration. The relational equation E is different for each reference solenoid valve 60. The reference relational equation Es is obtained by averaging or taking the median of multiple relational equations E (obtained from multiple reference solenoid valves 60). Similarly, the solenoid valve 20 used in the actual machine also has variations (individual differences), and the relational equation E cannot be uniformly determined.

[0064] Let's assume that an actual vehicle 50 (actual machine) is equipped with an actual machine solenoid valve 20. When converting the electrical resistance Ω related to the actual machine solenoid valve 20 to an estimated temperature T, if we use the reference relation Es obtained from the reference solenoid valve 60 as is, we cannot reflect the variation factors (manufacturing errors) of the actual machine solenoid valve 20, and therefore the temperature of the hydraulic fluid W cannot be estimated accurately (the estimated temperature T will be incorrect).

[0065] In this embodiment, the relational expression E is corrected from the reference relational expression Es to the corrected relational expression Ec by implementing the following improvements. This makes it possible to reflect the variation factors of the actual solenoid valve 20 in the corrected relational expression Ec, and to accurately estimate the temperature of the hydraulic fluid W as the estimated temperature T.

[0066] (Correction from base relation to correction relation) Figure 5 shows the correction from the reference relation Es to the correction relation Ec. The horizontal axis represents the estimated temperature T, and the vertical axis represents the electrical resistance Ω. The reference relation Es is shown as a solid line, and the correction relation Ec is shown as a dashed line.

[0067] As described above, at the time before the vehicle 50 is shipped, the memory 32 of the estimation device 30 stores the reference relation Es. The reference relation Es is known. On the other hand, at the time before the vehicle 50 is shipped, the memory 32 of the estimation device 30 does not store the correction relation Ec. The correction relation Ec is unknown. The reference relation Es and the correction relation Ec are likely to be different from each other, but they could also be the same.

[0068] The reference relation Es (known) is expressed as a linear equation (linear function) with electrical resistance Ω and estimated temperature T as variables. The reference relation Es is expressed by equation [Equation 1].

[0069]

number

[0070] The correction relation Ec(unknown) is expressed as a linear equation (linear function) with electrical resistance Ω and estimated temperature T as variables. The correction relation Ec is expressed by equation [Equation 2].

[0071]

number

[0072] T is a variable representing the estimated temperature, Ω(T) is a function of T and represents the electrical resistance, t is a constant representing a specific estimated temperature, Ω(t) is a constant representing the specific electrical resistance of the reference solenoid valve 60 when the estimated temperature is t, Ω(t)' is a constant representing the specific electrical resistance Ω of the actual solenoid valve 20 when the estimated temperature is t, and α is a constant.

[0073] α is known. Since α is a constant that depends on the material (mainly metal) of the solenoid valve, it will have the same value for the reference solenoid valve 60 and the actual machine solenoid valve 20, which are of the same specifications. Note that other factors may be included in α.

[0074] t is known. t is a constant representing a specific estimated temperature T, and it is a concrete value.

[0075] Substituting T=t into the reference solenoid valve 60 (reference relation Es), we obtain the specific value Ω(T)=Ω(t). Substituting T=t into the actual machine solenoid valve 20 (correction relation Ec), we obtain the specific value Ω(T)=Ω(t)'.

[0076] The reference solenoid valve 60 and the actual machine solenoid valve 20 are identical in specifications, but they differ slightly due to variations (individual differences). Therefore, even when substituting the same T=t, Ω(t) in the reference solenoid valve 60 and Ω(t)' in the actual machine solenoid valve 20 are likely to be different values ​​(Ω(t)≠Ω(t)'). However, Ω(t) and Ω(t)' may be the same value. Ω(t) is known, while Ω(t)' is unknown.

[0077] The learning unit 31e of the estimation device 30 transforms equation [Equation 2] in the unknown correction relation Ec to obtain equation [Equation 3].

[0078]

number

[0079] The learning unit 31e of the estimation device 30 calculates Ω(t)' by substituting the measured temperature tm measured by the temperature sensor 10 for T (T=tm) and the electrical resistance Ωm related to the solenoid valve 20 for the actual machine for Ω(T) (Ω(T)=Ωm) in the unknown correction relation Ec (especially [Equation 3]). As a result, Ω(t)' is obtained as a specific value, as shown in Equation [Equation 4].

[0080]

number

[0081] The measured temperature tm is measured by the temperature sensor 10. The electrical resistance Ωm of the actual solenoid valve 20 is calculated based on the voltage V applied by the valve drive unit 31a of the estimation device 30 to the coil 21a of the actual solenoid valve 20, and the current A measured by the current sensor 40.

[0082] The learning unit 31e of the estimation device 30 substitutes the measured temperature tm, measured by the temperature sensor 10 after a predetermined time D has elapsed since the flow of hydraulic fluid W to the reduction gear 51 was stopped, into T. The learning unit 31e of the estimation device 30 substitutes the electrical resistance Ωm related to the actual solenoid valve 20, calculated (based on the applied voltage V and the current A measured by the current sensor 40) after a predetermined time D has elapsed since the flow of hydraulic fluid W to the reduction gear 51 was stopped, into Ω(T).

[0083] The period after a predetermined time D has elapsed since the flow of hydraulic fluid W to the reduction gear 51 was stopped is also the period after a predetermined time D has elapsed since the vehicle 50 was stopped and left unattended (soaked). At this time, the measured temperature tm measured by the temperature sensor 10 after the predetermined time D should be almost the same as the estimated temperature converted from the electrical resistance Ωm (calculated based on the voltage V and current A obtained after the predetermined time D), and should be almost the same as the ambient temperature (in which the vehicle 50 is placed). The predetermined time D is, for example, about 6 hours.

[0084] It is preferable that the measured temperature tm is different from t. Therefore, when generating the reference relation Es, it is best to set t to a value that is far from the measured temperature tm (which should be close to the ambient temperature).

[0085] The learning unit 31e of the estimation device 30 determines Ω(t)'. After determining Ω(t)', the learning unit 31e of the estimation device 30 does not perform any further calculations to find Ω(t)'. In this example, Ω(t)' is determined in a single calculation (without performing the repeated calculations described later).

[0086] After Ω(t)' is determined, substituting equation [Equation 4] into equation [Equation 2] yields equation [Equation 5].

[0087]

number

[0088] The previously unknown correction relation Ec can be obtained using [Equation 5].

[0089] In this way, the learning unit 31e of the estimation device 30 corrects the reference relation Es (stored in the memory 32 of the estimation device 30) to the correction relation Ec based on the electrical resistance Ωm of the actual solenoid valve 20 and the measured temperature tm measured by the temperature sensor 10.

[0090] In detail, the learning unit 31e of the estimation device 30 corrects the reference relation expression Es (stored in the memory 32 of the estimation device 30) to the correction relation expression Ec based on the electrical resistance Ωm and the measured temperature tm (measured by the temperature sensor 10) related to the solenoid valve 20 for the actual machine, which are obtained after a predetermined time D has elapsed since the flow of hydraulic fluid W to the reduction gear 51 was stopped.

[0091] (flowchart) Figure 6 shows a flowchart for correcting the reference relation Es to the correction relation Ec. The premise is that the vehicle 50 is undergoing pre-shipment setup. Starting from the beginning, in the first step S1, the memory 32 of the estimation device 30 stores the reference relation Es. At this point, the reference relation Es is known (Equation [Equation 1]), and the correction relation Ec is unknown (Equation [Equation 2]).

[0092] In the second step S2, the flow of hydraulic fluid W to the reduction gear 51 is stopped, and a predetermined time D is waited for to elapse (waiting for soaking).

[0093] In the third step S3, the valve drive unit 31a of the estimation device 30 applies a voltage V to the coil 21a of the actual solenoid valve 20 at a predetermined duty cycle [%]. If the set value of the duty cycle is known, the value of the applied voltage V can also be determined.

[0094] In the fourth step S4, the current sensor 40 measures the current A flowing through the coil 21a of the solenoid valve 20 for the actual device.

[0095] In the fifth step S5, the resistance calculation unit 31b of the estimation device 30 calculates the electrical resistance Ωm based on the voltage V and current A.

[0096] In step 6, S6, the temperature sensor 10 measures the measurement temperature tm of the hydraulic fluid W.

[0097] In the seventh step S7, the learning unit 31e of the estimation device 30 calculates Ω(t)' by substituting the measured temperature tm for T (T=tm) and the electrical resistance Ωm for Ω(T) (Ω(T)=Ωm) in the unknown correction relation Ec (especially Equation 3) (Equations 3 and 4).

[0098] In step 8, S8, the learning unit 31e of the estimation device 30 determines Ω(t)'. After determining Ω(t)', the learning unit 31e of the estimation device 30 does not perform any further calculations to find Ω(t)'.

[0099] In the ninth step S9, the learning unit 31e of the estimation device 30 obtains the known correction relation Ec based on the determined Ω(t)'. That is, in the ninth step S9, the learning unit 31e of the estimation device 30 corrects the reference relation Es (stored in the memory 32 of the estimation device 30) to the correction relation Ec based on the determined Ω(t)'.

[0100] And then, we reach the end.

[0101] (Effects and Benefits) When converting the electrical resistance Ω(T) of the actual solenoid valve 20 to the estimated temperature T of the hydraulic fluid W, if the reference relation Es obtained from the reference solenoid valve 60 is used as is, the variation factors of the actual solenoid valve 20 (such as manufacturing errors) cannot be reflected, and therefore the temperature of the hydraulic fluid W flowing through the reduction gear 51 of the vehicle 50 cannot be estimated accurately (the accuracy of the estimated temperature T is poor).

[0102] Therefore, the reference relation Es is corrected to the correction relation Ec based on the electrical resistance Ωm of the solenoid valve 20 for the actual machine and the measured temperature tm of the hydraulic fluid W measured by the temperature sensor 10.

[0103] When converting the electrical resistance Ω(T) of the actual solenoid valve 20 to the estimated temperature T of the hydraulic fluid W, the correction relation Ec can be used to reflect the variation factors of the actual solenoid valve 20, and the temperature of the hydraulic fluid W flowing through the reduction gear 51 of the vehicle 50 can be accurately estimated as the estimated temperature T (the accuracy of the estimated temperature T can be improved).

[0104] As described above, with this simple configuration, the temperature of the hydraulic fluid W flowing through the reduction gear 51 of the vehicle 50 can be estimated with high accuracy.

[0105] The validity of the measured temperature of the hydraulic fluid W measured by the temperature sensor 10 can be determined, and furthermore, the temperature sensor 10 can be fault-diagnosed.

[0106] Since the entire reference relation Es is corrected to the correction relation Ec, the estimation accuracy is higher compared to setting a uniform correction value regardless of the value, and conversely, the calculation is simpler compared to setting a correction value for each value individually.

[0107] This eliminates the need for a map that records the relationship between the electrical resistance of the actual solenoid valve 20 and the temperature of the hydraulic fluid W for each value.

[0108] The reference relation Es can be simply expressed as a linear equation with electrical resistance Ω(T) and estimated temperature T as variables.

[0109] The reference relation Es and the correction relation Ec can be expressed simply by equations [Equation 1] and [Equation 2].

[0110] The learning unit 31e of the estimation device 30 calculates Ω(t)' by substituting the measured temperature tm measured by the temperature sensor 10 for T (T=tm) and the electrical resistance Ωm related to the actual solenoid valve 20 for Ω(T) (Ω(T)=Ωm) in the unknown correction relation Ec (especially [Equation 3]). By calculating Ω(t)' based on the electrical resistance Ωm related to the actual solenoid valve 20 and the measured temperature tm measured by the temperature sensor 10, the reference relation Es can be corrected to the correction relation Ec.

[0111] Since the correction relation Ec, which is determined along with the determination of Ω(t)', is used without modification, the calculation of converting from electrical resistance Ω(T) to estimated temperature T can be simplified.

[0112] The learning unit 31e of the estimation device 30 determines Ω(t)' based on the electrical resistance Ωm and the measured temperature tm (measured by the temperature sensor 10) related to the solenoid valve 20 for the actual machine, which are obtained after a predetermined time D has elapsed since the flow of hydraulic fluid W to the reduction gear 51 was stopped, and corrects the reference relation Es to the correction relation Ec. Since the estimated temperature estimated from the electrical resistance Ωm and the measured temperature tm measured by the temperature sensor 10 are almost the same, Ω(t)' can be determined with high accuracy, and consequently, the correction relation Ec can be determined with high accuracy.

[0113] The electrical resistance Ω can be easily determined based on the voltage V applied by the valve drive unit 31a of the estimation device 30 to the actual solenoid valve 20, and the current A (flowing through the actual solenoid valve 20) measured by the current sensor 40.

[0114] <Second Embodiment> A second embodiment will now be described. In the following description, components similar to those in the above embodiment will be denoted by the same reference numerals, and detailed descriptions will be omitted. Figure 7 shows a flowchart.

[0115] Starting from the beginning, in the first step K1, the memory 32 of the estimation device 30 stores the reference relation Es. At this point, the reference relation Es is known, and the correction relation Ec is unknown.

[0116] In the second step K2, the learning unit 31e of the estimation device 30 sets the maximum number of learning iterations N. The maximum number of learning iterations N is an example of a predetermined number. For example, the maximum number of learning iterations N may be 50.

[0117] In the third step K3, the learning unit 31e of the estimation device 30 is initialized to 1 for the current number of learning iterations n.

[0118] In the fourth step K4, the flow of hydraulic fluid W to the reduction gear 51 is stopped, and a predetermined time D is waited for to elapse (waiting for soaking).

[0119] In the fifth step K5, the valve drive unit 31a of the estimation device 30 applies a voltage V to the coil 21a of the solenoid valve 20 for the actual machine at a predetermined duty ratio [%]. If the set value of the duty ratio is known, the value of the applied voltage V can also be known.

[0120] In the sixth step K6, the current sensor 40 measures the current A flowing through the coil 21a of the solenoid valve 20 for the actual machine.

[0121] In the seventh step K7, the resistance calculation unit 31b of the estimation device 30 calculates the electrical resistance Ωm n based on the voltage V and the current A.

[0122] In the eighth step K8, the temperature sensor 10 measures the measured temperature tm n of the working oil W.

[0123] In the ninth step K9, the learning unit 31e of the estimation device 30 substitutes the measured temperature tm n for T (T = tm n ) and substitutes the electrical resistance Ωm n for Ω(T) to obtain Ω(t) n ’. Note that Ω(t)’ in Equation [Equation 2] and Equation [Equation 3] may be read as Ω(t) n ’.

[0124] Here, the subscript n corresponds to the current learning count n. For example, when the current learning count n is 1 (n = 1), it becomes tm1, Ωm1, and Ω(t)1’.

[0125] In the tenth step K10, the learning unit 31e of the estimation device 30 obtains the reflection value Ω(t) n ’ based on Ω(t) adn ’. The reflection value Ω(t) adn ’ is obtained by Equation [Equation 6].

[0126]

Equation

[0127] When the current number of learning times n is 1 (n = 1), the formula becomes Equation [Equation 7].

[0128]

Equation

[0129] Here, if Ω(t) ad0 ’ is, for the sake of convenience, set as Ω(t) in the reference relational expression Es, the formula becomes Equation [Equation 8]. Note that Ω(t) is known.

[0130]

Equation

[0131] In the 11th step K11, it is determined whether the current number of learning times n has reached the maximum number of learning times N (= 50) (n ≥ N?). If the current number of learning times n has not reached the maximum number of learning times N (n < N), proceed to the 12th step K12. If the current number of learning times n has reached the maximum number of learning times N (n ≥ N), proceed to the 13th step K13.

[0132] In the 12th step K12, the learning unit 31e of the estimation device 30 increases the current number of learning times n by 1. For example, after n = 1, n = 2. When the 12th step K12 ends, return to the 5th step K5.

[0133] By the way, in the 10th step K10, when the current number of learning times n is 2 (n = 2), the formula becomes Equation [Equation 9], and when the current number of learning times n is 3 (n = 3), the formula becomes Equation [Equation 10].

[0134]

Equation

[0136] As mentioned above, if the current number of learning iterations n has reached the maximum number of learning iterations N (=50) (n≧N), proceed to step 13, K13.

[0137] In step 13, K13, the learning unit 31e of the estimation device 30 determines the reflection value Ω(t) adn We use ' to determine Ω(t)'. Specifically, we use the reflected value Ω(t) adn 'Then, confirm (Ω(t)'=Ω(t) adn In this example, the repeated learning process ends when n=N=50, so Ω(t)'=Ω(t) ad50 'It will be.'

[0138] The learning unit 31e of the estimation device 30 determines that Ω(t)' is the reflected value Ω(t) adn Once it is determined that Ω(t)' is found, no further calculations are performed to find Ω(t).

[0139] In the 14th step K14, the learning unit 31e of the estimation device 30 obtains the known correction relation Ec based on the determined Ω(t)'. That is, in the 14th step K14, the learning unit 31e of the estimation device 30 corrects the reference relation Es (stored in the memory 32 of the estimation device 30) to the correction relation Ec based on the determined Ω(t)'.

[0140] And then, we reach the end.

[0141] In this embodiment, the learning unit 31e of the estimation device 30 performs calculations to find Ω(t)' under different conditions (different tm n and Ωm n The process is repeated a maximum of N learning iterations to train (update) Ω(t)'. Specifically, the learning unit 31e of the estimation device 30 learns (updates) different conditions (different tm n and Ωm n ) The reflected value Ω(t) adn The calculation is repeated for a maximum of N learning times. The learning unit 31e of the estimation device 30 calculates the final reflection value Ω(t) obtained by repeating the calculation for a maximum of N learning times.adn We define ' as Ω(t)'.

[0142] The other configurations are the same as in the first embodiment.

[0143] The reliability of Ω(t)' can be improved, and as a result, the reliability of the correction relation Ec can be improved.

[0144] <Other Embodiments> Although this disclosure has been described above with reference to preferred embodiments, this description is not limiting, and various modifications, substitutions, or combinations are, of course, possible.

[0145] The temperature estimation system 1 does not need to be used. The temperature estimation method according to this disclosure measures the temperature of the hydraulic fluid W flowing through the reduction gear 51 mounted on the vehicle 50 as the measured temperature, estimates the temperature of the hydraulic fluid W as the estimated temperature T based on the electrical resistance Ω of the actual machine solenoid valve 20 located in the flow path 52 through which the hydraulic fluid W flows, stores a relational expression E for converting the electrical resistance Ω(T) of a reference solenoid valve 60, which is different from the actual machine solenoid valve 20, to the estimated temperature T as the reference relational expression Es, and corrects the reference relational expression Es to a correction relational expression Ec based on the electrical resistance Ωm of the actual machine solenoid valve 20 and the measured temperature tm.

[0146] A voltage sensor separate from the estimation device 30 may measure the voltage V applied to the actual solenoid valve 20.

[0147] Instead of the reduction gear 51, an engine or motor may be used as the mounted component. In this case, instead of the hydraulic oil W, cooling water for cooling the engine or motor may be used as the fluid. Furthermore, a cooling water solenoid valve placed in the cooling water line as a flow path may be used as the actual machine flow path component and the reference flow path component. In this case, the first indicator is the electrical resistance related to the cooling water solenoid valve. The electrical resistance related to the cooling water solenoid valve is converted into the estimated temperature of the cooling water. This can be applied to fault diagnosis of a cooling water temperature sensor placed in the cooling water line as a flow path.

[0148] In practice, other machines may be used instead of vehicle 50. For example, other transportation equipment or industrial machinery may be used as the actual machine.

[0149] Other flow path components besides solenoid valves may be used as flow path components for the actual machine and reference flow path components. For example, a thermostat valve placed in the cooling water line as a flow path may be used as a flow path component for the actual machine and reference flow path component. A thermostat valve opens and closes due to expansion and contraction caused by temperature changes. The first indicator may be the opening degree of the thermostat valve. The opening degree can be measured by an opening degree sensor or the like. The opening degree of the thermostat valve is converted into an estimated temperature of the cooling water. This can be applied to fault diagnosis of a cooling water temperature sensor placed in the cooling water line as a flow path.

[0150] Other flow path components besides valves may be used as flow path components for the actual machine and as reference flow path components. [Industrial applicability]

[0151] This disclosure is extremely useful and highly industrially applicable, as it can be applied to temperature estimation systems and vehicles, as well as temperature estimation methods. [Explanation of symbols]

[0152] W Hydraulic oil (fluid) E Relational Expression Es criterion relation Ec Correction Relations V Voltage A current Ω Electrical resistance (first index) Ω(T) Electrical resistance (1st index) Ω(t) Electrical resistance (first index) Ω(t)' electrical resistance (first index) Ωm Electrical resistance (first index) T estimated temperature t Estimated temperature tm Measurement temperature D Predetermined time N Maximum number of learning iterations (predetermined number of iterations) n Number of training sessions 1. Temperature Estimation System 10 Temperature Sensor 20. Solenoid valve for actual machine (flow path component for actual machine) 30 Estimation device 40 Current Sensor 50 vehicles (actual machines) 51. Gear reducer (mounted component) 52 channels 60. Reference solenoid valve (reference flow path component)

Claims

1. A temperature sensor that measures the temperature of the fluid flowing through the components installed in the actual machine, A flow channel component for the actual machine, which is placed in the flow channel through which the aforementioned fluid flows, The system includes an estimation device that estimates the temperature of the fluid as an estimated temperature based on a first indicator relating to the flow path component for the actual machine, The estimation device stores a relational expression for converting the first index related to a reference flow channel component, which is different from the actual flow channel component, into the estimated temperature, as a reference relational expression. The estimation device is a temperature estimation system that corrects the reference relational expression to a correction relational expression based on the first index relating to the flow channel component for the actual machine and the measured temperature measured by the temperature sensor.

2. The aforementioned flow path component for the actual machine is a solenoid valve for the actual machine. The aforementioned reference flow path component is a reference solenoid valve, The temperature estimation system according to claim 1, wherein the first indicator is electrical resistance.

3. The temperature estimation system according to claim 2, wherein the reference relation is expressed as a linear equation with the electrical resistance and the estimated temperature as variables.

4. The aforementioned reference relation is expressed as Ω(T) = Ω(t) × {α × (T - t) + 1}, The aforementioned correction relation is expressed as Ω(T) = Ω(t)' × {α × (T - t) + 1}, The temperature estimation system according to claim 3, wherein T is a variable representing the estimated temperature, Ω(T) is a function of T and is a variable representing the electrical resistance, t is a constant representing a specific estimated temperature, Ω(t) is a constant representing a specific electrical resistance related to the reference solenoid valve when the estimated temperature is t, Ω(t)' is a constant representing a specific electrical resistance related to the actual solenoid valve when the estimated temperature is t, and α is a constant.

5. The temperature estimation system according to claim 4, wherein the estimation device determines Ω(t)' by substituting the measured temperature measured by the temperature sensor for T in the unknown correction relation formula, and substituting the electrical resistance related to the actual solenoid valve for Ω(T).

6. The temperature estimation system according to claim 5, wherein the estimation device repeatedly performs calculations to obtain Ω(t)' under different conditions for a predetermined number of times to learn Ω(t)'.

7. The temperature estimation system according to claim 5 or 6, wherein the estimation device does not perform calculations to determine Ω(t)' after Ω(t)' has been determined.

8. The temperature estimation system according to any one of claims 2 to 6, wherein the estimation device corrects the reference relation to the correction relation based on the electrical resistance obtained after a predetermined time has elapsed since the fluid flow to the mounted component was stopped and the measured temperature.

9. The system includes a current sensor for measuring the current flowing through the solenoid valve for the actual machine, The estimation device drives the solenoid valve for the actual machine by applying a voltage to the solenoid valve for the actual machine, The temperature estimation system according to any one of claims 2 to 6, wherein the estimation device calculates the electrical resistance based on the voltage and the current.

10. The aforementioned actual machine is a vehicle, The aforementioned mounted component is a gearbox, The temperature estimation system according to any one of claims 2 to 6, wherein the fluid is a hydraulic fluid for operating the speed reducer.

11. The aforementioned reduction gear and, A vehicle comprising the temperature estimation system described in claim 10.

12. The temperature of the fluid flowing through the components installed in the actual machine is measured as the measured temperature. Based on a first indicator relating to a flow path component for the actual machine that is placed in the flow path through which the fluid flows, the temperature of the fluid is estimated as the estimated temperature. A relational expression for converting the first index related to a reference flow channel component, which is different from the flow channel component for the actual machine, into the estimated temperature is stored as a reference relational expression. A temperature estimation method that corrects the reference relational expression to a correction relational expression based on the first index relating to the flow path component for the actual machine and the measured temperature.

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