In-vehicle temperature estimation device

Abstract

An in-vehicle temperature estimation device (30) is applied to an in-vehicle heating object (11) heated by energization. The in-vehicle temperature estimation device (30) has a power detection unit (20A) that detects supplied power (P) supplied to the heating object (11), a calculation unit (20C) that performs a calculation for estimating the temperature of a first object position (P2) in the heating object (11), and a temperature-specifying unit (20B) that specifies the temperature of the outside air outside of the heating object (11). The calculation unit (20C) performs the calculation for estimating the temperature of the first object position (P2) on the basis of the supplied power (P) detected by the power detection unit (20A) and the temperature of the outside air specified by the temperature-specifying unit (20B).

Description

[Technical Field]

[0001] The present disclosure relates to an in-vehicle temperature estimation device. [Background technology]

[0002] Patent Document 1 discloses a technique for controlling the supply of power to an electrically heated catalyst (hereinafter also simply referred to as an EHC (Electrically Heated Catalyst)) that purifies exhaust gas from an internal combustion engine, using an EHC control device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-134187 [Patent Document 2] Japanese Patent Application Publication No. 10-339130 Summary of the Invention [Problem to be solved by the invention]

[0004] Known methods for acquiring the temperature of an EHC include embedding a temperature sensor in the EHC to measure the temperature directly, and estimating the temperature based on the EHC's resistance value using the EHC's NTC (Negative Temperature Coefficient) characteristics. However, embedding a temperature sensor is time-consuming. Furthermore, the NTC characteristics may tend to result in a smaller rate of change in resistance relative to the rate of change in temperature as the EHC temperature increases. When the EHC temperature is in a temperature range exhibiting this tendency, the temperature estimated based on the resistance value may not be accurate. Therefore, a technology capable of accurately estimating the EHC temperature is desired.

[0005] The present disclosure was completed in light of the above circumstances, and aims to provide an in-vehicle temperature estimation device that can accurately estimate the temperature of a heating object. [Means for solving the problem]

[0006] The in-vehicle temperature estimation device of the present disclosure includes: It is applied to heating objects in vehicles that are heated by passing electricity. a power detection unit that detects power supplied to the heating object; a calculation unit that performs calculations to estimate a temperature at a target position on the heating target; a temperature specifying unit that specifies an outside air temperature outside the heating target; and The calculation unit performs a calculation to estimate the temperature of the target position based on the supplied power detected by the power detection unit and the outside air temperature identified by the temperature identification unit. [Effects of the Invention]

[0007] According to the present disclosure, the temperature of the heating target can be estimated with high accuracy. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a configuration of an in-vehicle system according to the first embodiment. [Figure 2] FIG. 2 is a graph showing the resistance and temperature characteristics of a resistive portion of a heating object. [Figure 3] FIG. 3 is a cross-sectional view of the heating target in the first embodiment, cut in a direction perpendicular to the central axis. [Figure 4] FIG. 4 is a thermal circuit model of the heating target in the first embodiment. [Figure 5] FIG. 5 is a cross-sectional view of the heating target in the second embodiment, cut in a direction perpendicular to the central axis. [Figure 6] FIG. 6 is a thermal circuit model of the heating target in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] In the following, embodiments of the present disclosure are listed and illustrated.

[0010] [1] The in-vehicle temperature estimation device of the present disclosure is applied to an in-vehicle heating target that is heated by passing electricity. The in-vehicle temperature estimation device includes a power detection unit that detects the supply power supplied to the heating target, a calculation unit that performs calculations to estimate the temperature of the target position on the heating target, and a temperature determination unit that determines the temperature of the outside air outside the heating target. The calculation unit performs calculations to estimate the temperature of the target position based on the supply power detected by the power detection unit and the outside air temperature determined by the temperature determination unit.

[0011] The in-vehicle temperature estimation device described in [1] above can estimate the temperature at a target position without providing a configuration for directly measuring the temperature at the target position.

[0012] [2] The temperature of the outside air in [1] above may include the temperature of the inflow gas flowing into the heating object, the temperature identification unit may detect the temperature of the inflow gas, and the calculation unit may perform calculations to estimate the temperature of the target position based on the supplied power and the temperature of the inflow gas.

[0013] Since the inflowing gas flows into the object to be heated, it can have a significant effect on the temperature of the object to be heated. Therefore, the in-vehicle temperature estimation device described in [2] above can more accurately estimate the temperature of the object to be heated by detecting the temperature of this inflowing gas.

[0014] [3] The calculation unit of [1] or [2] above may perform calculations to estimate temperatures at a plurality of target positions on the heating target based on the supplied power and the temperature of the outside air.

[0015] The in-vehicle temperature estimation device of [3] above estimates the temperatures at a plurality of target positions, and therefore can more precisely estimate the temperature at the heating target.

[0016] [4] The calculation unit of the in-vehicle temperature estimation device of [3] above estimates the temperature of a first target position among the plurality of target positions after a predetermined time has elapsed based on the current temperature of the first target position, the outside air thermal resistance from the first target position to the outside air of the heating target, the heat capacity of the first target position, the current temperature of a second target position among the plurality of target positions that is different from the first target position, the internal thermal resistance from the first target position to the second target position, and the temperature of the outside air. The calculation unit may estimate the temperature of the second target position after a predetermined time has elapsed based on the supplied power, the current temperature of the first target position, the current temperature of the second target position, the internal thermal resistance from the second target position to the first target position, and the internal heat capacity of the second target position.

[0017] The in-vehicle temperature estimation device of [4] estimates the temperatures of multiple target positions (first target position and second target position), allowing for more precise estimation of the temperature of the heating target. Furthermore, it is possible to know in advance the temperature of each target position after a predetermined time has elapsed, making it possible to control the temperature of the actual target position so that it does not reach a temperature that should be avoided.

[0018] [5] The calculation unit of the in-vehicle temperature estimation device of [1] or [2] above may estimate the temperature at the target position after a predetermined time has elapsed based on the supplied power, the current temperature at the target position, the outside air thermal resistance from the target position to the outside air of the heating target, the heat capacity of the target position, and the outside air temperature.

[0019] The in-vehicle temperature estimation device described in [5] above can grasp the temperature at the target location after a predetermined time has elapsed in advance, and can control the temperature at the actual target location so that it does not reach a temperature that should be avoided.

[0020] [6] The vehicle-mounted temperature estimation device of [4] or [5] above may further have an adjustment unit that adjusts the outside air side thermal resistance based on at least one of the temperature of the outside air or the flow rate of the outside air flowing into the object to be heated.

[0021] The in-vehicle temperature estimation device described in [6] above can take into account the temperature of the outside air and the flow rate of the gas flowing into the object to be heated into the outside air thermal resistance, thereby enabling more accurate estimation of the temperature at the target position.

[0022] [7] The heating target to which any one of the above-described in-vehicle temperature estimation devices [1] to [6] is applied may be an EHC arranged in an exhaust path of exhaust gas emitted from an internal combustion engine.

[0023] The on-board temperature estimation device described in [7] above can estimate the temperature of the EHC, thereby enabling control to effectively purify exhaust gas.

[0024] [8] The adjusting unit of [7], which cites the above [6], may adjust the outside air side thermal resistance based on the rotation speed of the internal combustion engine.

[0025] The on-board temperature estimation device of [8] above can take into account the rotation speed of the internal combustion engine, which can change from moment to moment, into the outside air side thermal resistance, so it can estimate the temperature in the EHC more accurately.

[0026] [9] The heating target is configured to operate by receiving power supply from a drive unit, and the in-vehicle temperature estimation device of [1] to [8] above has a power control unit that controls the drive unit. The power control unit may generate a temperature maintenance signal that controls the operation of the drive unit so as to maintain the temperature of the target position within a temperature range of a predetermined temperature maintenance region based on the calculation result of the calculation unit.

[0027] The in-vehicle temperature estimation device of [9] can control the temperature of the object to be heated by controlling the operation of the drive unit with the temperature maintenance signal generated by the power control unit.

[0028]

[10] The heating target has an NTC characteristic in which the resistance value decreases as the temperature of the heating target increases within a predetermined temperature range. The NTC characteristic has an insignificant change region in which the temperature characteristic of the resistance value of the heating target is smaller than the variation in the resistance value, and the calculation unit of the on-vehicle temperature estimation device of [9] above may perform calculations to estimate the temperature at the target position at least when the temperature of the heating target is in the temperature maintenance region and the insignificant change region.

[0029] The above-mentioned in-vehicle temperature estimation device

[10] can estimate the temperature at the target position well when the temperature characteristic of the resistance value of the heated object includes a temperature maintenance area in a small change area where the change is smaller than the variation in the resistance value.

[0030] <Embodiment 1> [In-vehicle system configuration] The in-vehicle system 100 shown in Figure 1 includes a power supply unit 10, a heated object 11, a power path 12, a DC-DC converter 13 which is a driving unit, a current detection unit 14, a voltage detection unit 15, and an in-vehicle temperature estimation device 30.

[0031] The power supply unit 10 is configured as a battery such as a lithium ion battery.

[0032] The heating target 11 is, for example, an EHC (electrically heated catalyst). The heating target 11 is disposed, for example, in an exhaust path of gas emitted from an internal combustion engine, and oxidizes hydrocarbons in the exhaust gas and reduces CO and NOx to purify the exhaust gas. The heating target 11 has a resistance portion 11A and a catalyst (not shown). The resistance portion 11A is configured as a substrate that supports the catalyst. The resistance portion 11A is configured from a conductive material. The resistance portion 11A of the heating target 11 has a characteristic (so-called NTC characteristic) in which, within a predetermined temperature range, the resistance value decreases as its own temperature increases. The resistance portion 11A generates heat when power is supplied. The heat generated by the resistance portion 11A is transferred to the catalyst, thereby heating the catalyst. When the catalyst is heated, it becomes activated. In other words, the heating target 11 is heated by passing electricity through it.

[0033] The resistor unit 11A has individual variations. Specifically, as shown in Fig. 2, the NTC characteristic of the resistor unit 11A has an upper limit characteristic U that indicates the upper limit of the individual variations and a lower limit characteristic D that indicates the lower limit of the individual variations. Therefore, the NTC characteristic indicates different resistance values ​​at each temperature: a resistance value Ru at the upper limit characteristic U and a resistance value Rd at the lower limit characteristic D. The difference between the resistance values ​​Ru and Rd is defined as a variation B of the resistance value of the resistor unit 11A (hereinafter also simply referred to as variation B).

[0034] Furthermore, the NTC characteristic has a central characteristic C sandwiched between an upper limit characteristic U and a lower limit characteristic D. The central characteristic C is, for example, a characteristic that indicates the average value of the upper limit characteristic U and the lower limit characteristic D at each temperature. In the NTC characteristic of the resistance section 11A, the temperature region between S1°C and S2°C is an insignificant change region S. In other words, the NTC characteristic has an insignificant change region S. Specifically, the insignificant change region S is a region where the amount of change Ac in the resistance value of the resistance section 11A of the heating target 11 due to a temperature change in the central characteristic C (temperature characteristic of the resistance value of the resistance section 11A) is smaller than the variation B in the resistance value of the resistance section 11A.

[0035] For example, the change in resistance value Ac of the resistance section 11A is the change when the temperature of the heating target 11 changes from S3°C to S4°C (a predetermined temperature) within the range of S1°C or higher and S2°C or lower. For example, S4°C - S3°C = 400°C to 800°C. Furthermore, the difference between the resistance value Ru of the upper limit characteristic U and the resistance value Rd of the lower limit characteristic D when the temperature of the heating target 11 is S3°C is the resistance variation B. For example, the variation B is 1.6Ω. In other words, the small change region S is a region where the change in resistance value Ac of the resistance section 11A of the heating target 11 when the resistance changes by a predetermined temperature (from S3°C to S4°C) is smaller than the resistance variation B within the predetermined temperature range. For example, the change Ac is 1.2Ω.

[0036] When heating the heating target 11, the temperature of the heating target 11 must be maintained between a predetermined upper limit and a predetermined lower limit. Specifically, the predetermined upper limit is the heat resistance temperature, which is the upper limit temperature at which deterioration of the heating target 11 can be suppressed, and the predetermined lower limit is the target temperature at which the heating target 11 can function as a catalyst. Deterioration of the heating target 11 refers to, for example, excessive heating, which causes the material to become brittle due to oxidation compared to when it was first installed in the exhaust path (i.e., when it was first manufactured), or to change from when it was first installed in the exhaust path and no longer function as a catalyst. In FIG. 2, the heat resistance temperature, which is the predetermined upper limit, is Rm2°C. The target temperature, which is the predetermined lower limit, is Rm1°C. Therefore, by maintaining the temperature of the heating target 11 at or above Rm1°C and below Rm2°C, the heating target 11 can function as a catalyst for a longer period of time. The temperature range from Rm1°C to Rm2°C is the temperature maintenance range Rm. In other words, the temperature maintaining region Rm is a region showing the temperature of the heating target 11 that allows the heating target 11 to perform its catalytic function well.

[0037] As shown in FIG. 1, the object to be heated 11 has a cylindrical shape. A pair of electrode plates 11B are attached to the outer peripheral surface of the object to be heated 11. These electrode plates 11B are formed in a semi-cylindrical shape so as to fit along the outer peripheral surface of the object to be heated 11. These electrode plates 11B are arranged on opposite sides of the outer peripheral surface of the object to be heated 11, sandwiching the object to be heated 11. These electrode plates 11B are arranged in the center of the object to be heated 11 in the central axis direction. One of the electrode plates 11B is electrically connected to a power path 12. The other electrode plate 11B is electrically connected to a reference conductive path G.

[0038] The power path 12 is a path for supplying power from the power supply unit 10 to the resistance unit 11A. The power path 12 is provided between the DC-DC converter 13 and the object 11 to be heated.

[0039] The DC-DC converter 13 is interposed between the power supply unit 10 and the heating target 11. The DC-DC converter 13 is, for example, a step-down type, and performs a step-down operation of stepping down the voltage applied to the power supply side conductive path 10A on the power supply unit 10 side and applying it to the power path 12 on the resistor unit 11A side. The DC-DC converter 13 uses a semiconductor switching element. For example, an N-channel type FET (Field Effect Transistor) is used as the semiconductor switching element. The N-channel type FET is turned on when a voltage equal to or greater than a threshold voltage is applied to the gate, and is turned off when a voltage less than the threshold voltage is applied to the gate or when no voltage is applied to the gate.

[0040] Current detection unit 14 detects the current flowing through resistance unit 11A. Current detection unit 14 is configured using, for example, a current transformer or a shunt resistor. Current detection unit 14 detects the current flowing through power path 12, and outputs a voltage value corresponding to the current flowing through resistance unit 11A as current value I to in-vehicle temperature estimation device 30.

[0041] The voltage detection unit 15 detects the potential of each of the pair of electrode plates 11B, and outputs the voltage applied to the resistance unit 11A as a voltage value E to the power control unit 20, which will be described later.

[0042] The in-vehicle temperature estimation device 30 is a device used in the in-vehicle system 100. The in-vehicle temperature estimation device 30 has an MCU (Micro Controller Unit), an AD converter, a DA converter, a drive circuit, and a multiplexer (not shown). The in-vehicle temperature estimation device 30 has a function of estimating the temperature of the heating target 11. The in-vehicle temperature estimation device 30 has a power detection unit 20A, a temperature identification unit 20B, a calculation unit 20C, an adjustment unit 20D, and a power control unit 20.

[0043] [Configuration of temperature estimation device] The power detection unit 20A has a function of detecting the power supplied to the heating target 11 based on the voltage value E detected by the voltage detection unit 15 and the current value I detected by the current detection unit 14. Specifically, the power detection unit 20A calculates the power by multiplying the voltage value E and the current value I.

[0044] The temperature specifying unit 20B has a function of specifying the temperature of the outside air outside the heating target 11. Specifically, the temperature specifying unit 20B calculates the temperature of the exhaust gas, which is the inflow gas flowing into the heating target 11, as the temperature T a The outside air temperature acquisition unit 20E has an outside air temperature acquisition unit 20E that acquires the temperature as an outside air temperature T. The outside air temperature acquisition unit 20E uses, for example, a temperature sensor such as a thermistor. The outside air temperature acquisition unit 20E is arranged, for example, in the exhaust path of the internal combustion engine, closer to the internal combustion engine (i.e., upstream side) than the heating object 11 or on the rear end side of the exhaust pipe (i.e., downstream side). The outside air temperature acquisition unit 20E has a function of detecting the temperature of inflow gas, which is gas just before it flows into the heating object 11, and the temperature of outflow gas, which is gas just after it flows out of the heating object 11. For example, the outside air temperature acquisition unit 20E is configured to be able to detect the temperature of the inflow gas after the ignition switch is switched from the off state to the on state and before the internal combustion engine starts operating. The outside air temperature acquisition unit 20E converts the temperature detected at this time into the outside air temperature T a (ambient temperature) to the power control unit 20, which will be described later.

[0045] The calculation unit 20C has a function capable of performing calculations to estimate the temperature of a first target position P2 (the center of the heating target 11) (see FIG. 3) among the multiple target positions on the heating target 11, and a second target position P1 among the multiple target positions. The calculation unit 20C estimates the temperature of the first target position P2 when the temperature of the heating target 11 is in the temperature maintenance region Rm and the slight change region S shown in FIG. 2. The calculation unit 20C estimates the temperature of the first target position P2, assuming the center of the heating target 11 as the first target position P2. The temperature of the first target position P2 on the heating target 11 is estimated using a thermal circuit model Cm shown in FIG. 4, which models the heating target 11.

[0046] The thermal circuit model Cm is a model of the flow of heat generated by the resistance part 11A due to the supplied power P, which heats the heated object 11, and the heat is then released from the heated object 11 to the outside. The thermal circuit model Cm is a model of the flow of heat generated by the resistance part 11A due to the supplied power P, the internal thermal resistance R1, the external air thermal resistance R2, the internal heat capacity C1, the heat capacity C2 at the first target position P2, and the external air temperature T a It is composed of:

[0047] The supply power P is the power supplied to the resistance portion 11A of the heating target 11. The supply power P is a value obtained by multiplying the current value I and the voltage value E input from the current detection portion 14 and the voltage detection portion 15. The supply power P is detected by the power detection portion 20A. The outside air temperature T a is a value detected by the outside air temperature acquisition unit 20E as the temperature of the inflow gas immediately before the gas flows into the heating target 11 before the internal combustion engine starts operating. a is determined by the temperature determination unit 20B. That is, the outside air temperature acquisition unit 20E of the temperature determination unit 20B determines the temperature at a different position outside the heating target 11 that is different from the first target position P2.

[0048] The internal thermal resistance R1, the internal heat capacity C1, the external air thermal resistance R2, and the heat capacity C2 at the first target position P2 are stored as predetermined fixed values ​​in a memory area provided in the in-vehicle temperature estimation device 30. The external air thermal resistance R2 is configured to be adjustable by an adjustment unit 20D, which will be described later. The internal thermal resistance R1, the internal heat capacity C1, the external air thermal resistance R2, and the heat capacity C2 at the first target position P2 may be calculated based on a predetermined mathematical formula, or values ​​corresponding to the external temperature, the rotation speed of the internal combustion engine, etc. may be selected from table data stored in the memory area.

[0049] The internal thermal resistance R1 is a characteristic that indicates the difficulty of heat transfer between a first target position P2 and a second target position P1 (hereinafter also referred to as the second target position P1) that is different from the first target position P2. The second target position P1 is, for example, the outer edge of the heating target 11, which is a portion covered by an electrode plate 11B that is electrically connected to the power path 12 (see FIG. 3). The external air thermal resistance R2 is a characteristic that indicates the difficulty of heat transfer between the first target position P2 and the surroundings of the heating target 11. The larger the values ​​of the internal thermal resistance R1 and the external air thermal resistance R2, the more difficult it is to transfer heat, and the smaller the values, the easier it is to transfer heat.

[0050] The internal heat capacity C1 represents the amount of heat that can be accumulated at the second target position P1. The heat capacity C2 at the first target position P2 represents the amount of heat that can be accumulated at the first target position P2. The outside air temperature T a is the temperature around the heating object 11.

[0051] The heat flow at the second target position P1 is expressed by the following mathematical formula (1).

number

[0052] P is the power supplied to the resistance portion 11A of the heating target 11, and Δt is a predetermined short time. 1Δt is the temperature at the second target position P1 when Δt has elapsed from the current time, T1 is the current temperature at the second target position P1, and T2 is the current temperature at the first target position P2. P*Δt is the amount of heat flowing into the second target position P1 of the heating target 11, ((-T1+T2) / R1)*Δt is the amount of heat flowing from the second target position P1 to the first target position P2, and C1*(T 1Δt -T1) is the amount of heat accumulated at the second target position P1. From the formula 1, the calculation unit 20C calculates the temperature T 1Δtis estimated based on the supplied power P, the current temperature T2 at the first target position P2, the current temperature T1 at the second target position P1, the internal thermal resistance R1 from the second target position P1 to the first target position P2, and the internal heat capacity C1 at the second target position P1.

[0053] The heat flow at the first target position P2 is expressed by the following mathematical formula (2).

number

[0054] T a is the temperature of the outside air detected by the outside air temperature acquisition unit 20E (i.e., the temperature around the heating target 11), and T 2Δt is the temperature at the first target position P2 when Δt has elapsed from the current time. ((T1-T2) / R1)*Δt is the amount of heat flowing from the second target position P1 to the first target position P2, and ((-T2+T a ) / R2)*Δt is the amount of heat released from the first target position P2 to the outside of the heating target 11, and C2*(T 2Δt -T2) is the amount of heat accumulated at the first target position P2. From the formula shown in Equation 2, the calculation unit 20C calculates the temperature T 2Δt is calculated by dividing the temperature T2 at the first target position P2 by the external air thermal resistance R2 from the first target position P2 to the external air of the heating target 11, the heat capacity C2 at the first target position P2, the current temperature T1 at a second target position P1 inside the heating target 11 that is different from the first target position P2, the internal thermal resistance R1 from the first target position P2 to the second target position P1, and the external air temperature T a That is, the calculation unit 20C estimates the temperature based on the supplied power P and the outside air temperature T a Based on this, a calculation is performed to estimate the temperatures of the first target position P2 and the second target position P1 (plurality of target positions) on the heating target 11.

[0055] For example, when the start switch (e.g., ignition switch) of the vehicle in which the in-vehicle system 100 is installed is in the OFF state, T1=T2=T aThis formula is valid when the start switch is kept in the OFF state for a long time and the temperature of the object to be heated 11 is sufficiently reduced to the outside air temperature T a Therefore, when the calculation unit 20C first executes the calculations in Equation 1 and Equation 2, T1=T2=T a By operating as 1Δt , T 2Δt T a The value detected by the outside air temperature acquisition unit 20E before the internal combustion engine is operated is used for T. Then, when the calculation unit 20C executes the calculations of Equations 1 and 2 in the next period, the previously calculated T 1Δt , T 2Δt By substituting each of these into T1 and T2, T after another Δt has elapsed 1Δt , T 2Δt In this way, the calculation unit 20C repeats the calculations of Equations 1 and 2 at predetermined intervals (for example, every Δt) based on the supplied power P detected by the power detection unit 20A and the temperature of the inflowing gas identified by the temperature identification unit 20B (the detection result of the outside air temperature acquisition unit 20E). Then, the calculation unit 20C calculates the temperature T at the second target position P1 after the lapse of the minute time Δt. 1Δt , the temperature T at the first target position P2 after a short time Δt has elapsed 2Δt The estimation operation is performed to sequentially estimate

[0056] The degree of heat transfer in the heating target 11 changes depending on the temperature and flow rate of the gas (exhaust gas from the internal combustion engine) flowing into the heating target 11. Therefore, by taking into account the temperature and flow rate of the gas (exhaust gas from the internal combustion engine) flowing into the heating target 11, it becomes possible to estimate the temperature in the heating target 11 more accurately.

[0057] For example, the outside air side thermal resistance R2 is inversely proportional to the value obtained by multiplying the convection heat transfer coefficient h by the area A of the object to be heated 11 that is in contact with the exhaust gas of the internal combustion engine. In other words, the outside air side thermal resistance R2 decreases as the convection heat transfer coefficient h increases. Here, the convection heat transfer coefficient h is a value that represents the ease of heat transfer between the inflow gas (exhaust gas of the internal combustion engine) flowing into the object to be heated 11 and the object to be heated 11. This convection heat transfer coefficient h is a function of the flow rate V of the inflow gas (exhaust gas of the internal combustion engine) flowing into the object to be heated 11. P (Hereafter, simply the flow rate V P It has the property that as the flow rate V increases, it also increases in proportion to the flow rate V P is the engine speed R E (Hereafter, simply the rotation speed R E (also called the exhaust-to-intake volume ratio r in an internal combustion engine) G (Hereafter, simply the volume ratio r G This can be calculated using the formula shown in Equation 3, which uses

[0058]

number

[0059] D[m 3 ] is the displacement of the internal combustion engine, which is a fixed value determined by the specifications of the internal combustion engine. P is the rotation speed R E and volume ratio r G Therefore, the convective heat transfer coefficient h is proportional to the flow rate V P , rotation speed R E , volume ratio r G The thermal resistance R2 on the outside air side is proportional to the convection heat transfer coefficient h and the flow rate V P , rotation speed R E , volume ratio r G In other words, the outdoor air thermal resistance R2 is inversely proportional to the flow rate V P , rotation speed R E , volume ratio r G The larger it is, the smaller it becomes.

[0060] For example, the power control unit 20 includes a rotation speed R E and volume ratio rG is input from the external ECU 60.

[0061] For example, the adjustment unit 20D uses the formula shown in Equation 3 to calculate the rotation speed R E and volume ratio r G Based on the flow rate V P Calculate the calculated flow rate V P The flow rate V in the adjusting unit 20D is calculated at predetermined intervals (for example, every Δt) to adjust the outdoor air side thermal resistance R2. P The calculation of the adjustment value Ad using the flow rate V can be performed, for example, by calculation based on a predetermined formula or by calculating the flow rate V from table data stored in the calculation. P It is conceivable to select an adjustment value Ad corresponding to the rotation speed R. Then, the adjustment unit 20D adjusts the outdoor air side thermal resistance R2 by subtracting the adjustment value Ad from the stored outdoor air side thermal resistance R2. Then, the calculation unit 20C estimates the temperature at the first target position P2 using the outdoor air side thermal resistance R2 adjusted by the adjustment unit 20D. In this way, the calculation unit 20C estimates the temperature at the first target position P2 by subtracting the adjustment value Ad from the stored outdoor air side thermal resistance R2. E and volume ratio r G The temperature of the object to be heated 11 is estimated taking into account the above.

[0062] flow rate V P , rotation speed R E , volume ratio r G As the flow rate V increases, the adjustment unit 20D changes the adjustment value Ad so as to decrease the outdoor air side thermal resistance R2. P , rotation speed R E , volume ratio r G The adjustment unit 20D adjusts the adjustment value Ad so that the outdoor air side thermal resistance R2 increases as the volume ratio r G may be set to a fixed value.

[0063] Furthermore, the adjustment unit 20D is T 2Δt T a When T is greater than 2Δt and T a The difference between 2ΔtAs the temperature T increases, the adjustment value Ad is changed to decrease the outdoor air side thermal resistance R2, thereby adjusting the outdoor air side thermal resistance R2. 2Δt T a When T is greater than 2Δt and T a The difference between 2Δt The adjustment value Ad is changed so that the outdoor air thermal resistance R2 increases as the temperature decreases. For example, the value calculated based on a predetermined formula or the table data stored in the T 2Δt and T a It is conceivable to add a value corresponding to the difference between the above to the adjustment value Ad, and then subtract the adjustment value Ad from the outdoor air side thermal resistance R2.

[0064] In this way, the adjusting unit 20D adjusts the flow rate V P , rotation speed R E , volume ratio r G In addition, the temperature T 2Δt In other words, the adjustment unit 20D calculates the adjustment value Ad at predetermined intervals (for example, every Δt) taking into account the outside air temperature T a and the flow rate V of the gas flowing into the heating object 11 P The calculation unit 20C then adjusts the outdoor air side thermal resistance R2 based on the above. Then, the calculation unit 20C uses the outdoor air side thermal resistance R2 adjusted by the adjustment unit 20D to perform an operation of estimating the temperature at the first target position P2.

[0065] The power control unit 20 includes a power detection unit 20A, a temperature determination unit 20B, a calculation unit 20C, an adjustment unit 20D, an MCU, an AD converter, a DA converter, a drive circuit, and a multiplexer. The power control unit 20 is configured to perform duty control, which outputs a temperature maintenance signal Ms having a set duty to the DC-DC converter 13 to turn the DC-DC converter 13 on and off. Duty control is, for example, PWM (Pulse Width Modulation) control. The duty is the ratio of the on time to the cycle. The duty setting is changeable. For example, the duty control is performed by the MCU and drive circuit included in the power control unit 20. In other words, the power control unit 20 controls the DC-DC converter 13.

[0066] The power control unit 20 starts duty control when a start condition is met. The start condition is, for example, that a start switch (e.g., an ignition switch) of the vehicle in which the in-vehicle system 100 is mounted has been switched to the on state. The power control unit 20 is configured to receive an on / off signal Si indicating the on / off state of the vehicle's start switch from an external ECU 60, and determines whether the start switch has been switched to the on state based on this on / off signal Si. When this start condition is met, the power control unit 20 calculates the temperature T 2Δt The temperature maintaining signal Ms generated based on the above is output to the DC-DC converter 13 to start duty control.

[0067] [Operation of the temperature estimation device] Next, a description will be given of an example of the operation of the in-vehicle temperature estimation device 30. First, the ignition switch of the vehicle equipped with the in-vehicle system 100 is switched to the on state. Then, an on / off signal Si indicating the on state is input from the external ECU 60 to the power control unit 20.

[0068] Then, at a timing before the internal combustion engine starts operating, the temperature specifying unit 20B acquires the temperature of the inflow gas immediately before it flows into the heating target 11 (i.e., the temperature Ta ) to get the

[0069] Then, when the start condition is met at a timing before the internal combustion engine starts to operate, the power control unit 20 generates a temperature maintenance signal Ms based on the temperature of the inflow gas immediately before it flows into the heating target 11, which is acquired from the outside air temperature acquisition unit 20E. Then, the power control unit 20 outputs the generated temperature maintenance signal Ms to the DC-DC converter 13 and starts duty control. Then, the supply of power to the resistance unit 11A starts, the temperature of the heating target 11 rises, and when the temperature of the heating target 11 reaches a predetermined temperature, the operation of the internal combustion engine starts. The condition for starting the operation of the internal combustion engine is, for example, the temperature T 2Δt , and the temperature T 1Δt The temperature has risen above the lower limit of the temperature maintenance region Rm, Rm1°C.

[0070] After the internal combustion engine starts operating, the power control unit 20 receives the rotation speed R E and volume ratio r G Then, the adjustment unit 20D starts inputting the rotation speed R E and volume ratio r G Based on the flow rate V P Calculate the calculated flow rate V P The adjustment value Ad is calculated using the above formula, and the adjustment of the outdoor air side thermal resistance R2 is started using this adjustment value Ad.

[0071] Then, the power control unit 20 starts duty control. In duty control, the power control unit 20 generates a signal (e.g., a PWM signal) with a set duty and outputs this signal to the DCDC converter 13 as a temperature maintenance signal Ms. As a result, the semiconductor switching element of the DCDC converter 13 is duty controlled by the power control unit 20, a direct current is supplied to the resistance unit 11A, and the current value I and the voltage value E are input to the power control unit 20 from the current detection unit 14 and the voltage detection unit 15. Then, the power detection unit 20A detects the supply power P to be supplied to the heating target 11 based on the current value I and the voltage value E. In other words, the heating target 11 is configured to operate by receiving power supply from the DCDC converter 13.

[0072] The calculation unit 20C calculates the outside air temperature T a , based on the supply power P detected by the power detection unit 20A, the temperature T 1Δt , T 2Δt The calculation unit 20C then calculates the temperatures T 1Δt , T 2Δt The estimation is continued every predetermined period (for example, every Δt).

[0073] And the temperature T 2Δt is the outside air temperature T a When the temperature T 2Δt and the outside air temperature T a The calculation unit 20C then uses the outdoor air side thermal resistance R2 adjusted by the adjustment unit 20D to perform the calculations of Equations 1 and 2 to calculate the temperatures T 1Δt , T 2Δt The estimation operation is performed.

[0074] Then, the power control unit 20 calculates the temperature T 2Δt Specifically, the duty of the temperature maintaining signal Ms is changed based on the temperature T 2ΔtThe magnitude of the duty (i.e., the temperature maintenance signal Ms) output to the DC-DC converter 13 is adjusted so that the estimated temperature T 2Δt When the estimated temperature T becomes larger than the temperature maintenance region Rm, the power control unit 20 reduces the duty and the current supplied to the resistance unit 11A. 2Δt becomes smaller than the temperature maintenance region Rm, the power control unit 20 increases the duty and increases the current supplied to the resistance unit 11A. In this way, the heating target 11 is maintained within the temperature range of the temperature maintenance region Rm by the temperature maintenance signal Ms output from the power control unit 20 (i.e., the outside). In this way, the power control unit 20 generates the temperature maintenance signal Ms that controls the operation of the DC-DC converter 13 so as to maintain the temperature of the first target position P2 within the temperature range of the predetermined temperature maintenance region Rm, based on the calculation result of the calculation unit 20C. Note that the temperature T estimated at the second target position P1 1Δt The duty may be changed taking into consideration the above.

[0075] Next, the effects of this configuration will be illustrated.

[0076] The in-vehicle temperature estimation device 30 is applied to an in-vehicle heating target 11 that is heated by energization. The in-vehicle temperature estimation device 30 has a power detection unit 20A, a calculation unit 20C, and a temperature determination unit 20B. The power detection unit 20A detects the supply power P supplied to the heating target 11. The calculation unit 20C performs calculations to estimate the temperatures of a first target position P2 and a second target position P1 on the heating target 11. The temperature determination unit 20B determines the outside air temperature T outside the heating target 11. a The calculation unit 20C determines the temperature T of the outside air based on the supplied power P detected by the power detection unit 20A and the temperature T of the outside air determined by the temperature determination unit 20B. a Based on this, the in-vehicle temperature estimation device 30 can estimate the temperatures of the first target position P2 and the second target position P1 without providing a configuration for directly measuring the temperatures of the first target position P2 and the second target position P1.

[0077] Outside air temperature T a includes the temperature of the inflow gas flowing into the heating target 11, the temperature specifying unit 20B detects the temperature of the inflow gas, and the calculation unit 20C performs calculations to estimate the temperatures of the first target position P2 and the second target position P1 based on the supplied power P and the temperature of the inflow gas. Because the inflow gas flows into the heating target 11, it can have a significant effect on the temperature of the heating target 11. Therefore, with this configuration, the temperature of the heating target 11 can be more accurately estimated by detecting the temperature of the inflow gas.

[0078] The calculation unit 20C calculates the supply power P and the outside air temperature T a Based on this, a calculation is performed to estimate the temperatures of the first target position P2 and the second target position P1 on the heating target 11. With this configuration, the temperatures of the first target position P2 and the second target position P1 (i.e., the temperatures of multiple target positions) are estimated, so that the temperature of the heating target 11 can be estimated more precisely.

[0079] The calculation unit 20C calculates the temperature T 2Δt is calculated by dividing the temperature T2 at the first target position P2 by the external air thermal resistance R2 from the first target position P2 to the external air of the heating target 11, the heat capacity C2 at the first target position P2, the current temperature T1 at a second target position P1 different from the first target position P2 among the plurality of target positions, the internal thermal resistance R1 from the first target position P2 to the second target position P1, and the external air temperature T aThe calculation unit 20C estimates the temperature at the second target position P1 after a predetermined short time Δt has elapsed based on the supplied power P, the current temperature T2 at the first target position P2, the current temperature T1 at the second target position P1, the internal thermal resistance R1 from the second target position P1 to the first target position P2, and the internal heat capacity C1 at the second target position P1. This configuration estimates the temperatures at the first target position P2 and the second target position P1 (i.e., the temperatures at multiple target positions), allowing for more precise estimation of the temperature at the heating target 11. Furthermore, the temperature at each target position after the predetermined short time Δt has elapsed can be known in advance, making it possible to control the actual temperature at each target position so that it does not reach a temperature that should be avoided.

[0080] The vehicle-mounted temperature estimation device 30 further estimates the outside air temperature T a , or the flow rate V of the gas flowing into the heating object 11 P According to this configuration, the outside air temperature T a and the flow rate V of the gas flowing into the heating object 11. P can be taken into account in the outdoor air side thermal resistance R2, so that the temperature at the first target position P2 can be estimated more accurately.

[0081] The heating target 11 is an EHC that is arranged in the exhaust path of exhaust gas emitted from an internal combustion engine. According to this configuration, by estimating the temperature of the EHC, it is possible to perform control to effectively purify the exhaust gas.

[0082] The adjustment unit 20D adjusts the rotation speed R of the internal combustion engine. E According to this configuration, the external air side thermal resistance R2 is adjusted based on the rotation speed R of the internal combustion engine, which may change from moment to moment. E can be added to the outdoor air thermal resistance R2, allowing for a more accurate estimation of the temperature at the EHC.

[0083] The heating target 11 is configured to operate by receiving power supply from a DCDC converter 13, and the in-vehicle temperature estimation device 30 has a power control unit 20 that controls the DCDC converter 13. The power control unit 20 generates a temperature maintenance signal Ms that controls the operation of the DCDC converter 13 so as to maintain the temperature of the first target position P2 within the temperature range of a predetermined temperature maintenance region Rm based on the calculation result of the calculation unit 20C. With this configuration, the temperature of the heating target 11 can be controlled by controlling the operation of the DCDC converter 13 with the temperature maintenance signal Ms generated by the power control unit 20.

[0084] The heating target 11 has an NTC characteristic, in which the resistance value decreases as the temperature of the heating target 11 increases within a predetermined temperature range. The NTC characteristic has an insignificant change region S where the temperature characteristic of the resistance value of the resistor portion 11A of the heating target 11 is smaller than the variation in the resistance value of the resistor portion 11A. The calculation unit 20C performs calculations to estimate the temperatures of the first target position P2 and the second target position P1 at least when the temperature of the heating target 11 is within the temperature maintenance region Rm and the insignificant change region S. With this configuration, the in-vehicle temperature estimation device 30 can successfully estimate the temperatures of the first target position P2 and the second target position P1 when the temperature maintenance region Rm is included in the insignificant change region S where the temperature characteristic of the resistance value of the resistor portion 11A of the heating target 11 is smaller than the variation in the resistance value of the resistor portion 11A.

[0085] <Embodiment 2> An in-vehicle temperature estimation device 130 according to a second embodiment of the present disclosure will be described with reference to Figures 1, 5, 6, etc. The in-vehicle temperature estimation device 130 according to the second embodiment differs from the first embodiment in the calculation method used by the calculation unit 20C to estimate the temperature of the target position P3 (the center of the target 11) in the target 11. The configuration of the in-vehicle temperature estimation device 130 is the same as that of the first embodiment. For the configuration of the in-vehicle temperature estimation device 130, refer to Figure 1, and a description of the same structure, actions, and effects as those of the first embodiment will be omitted.

[0086] The calculation unit 20C estimates the temperature at the center of the heating target 11 as a target position P3 (the center of the heating target 11) (see FIG. 5). The temperature at the target position P3 in the heating target 11 is estimated using a thermal circuit model Cm2 shown in FIG. 6, which models the heating target 11.

[0087] The thermal circuit model Cm2 is composed of the supply power P, the outside air thermal resistance R3, the heat capacity C3 at the target position P3, and the outside air temperature T a The outside air side thermal resistance R3 and the heat capacity C3 of the target position P3 are stored as predetermined fixed values ​​in a memory area provided in the in-vehicle temperature estimation device 130, for example. The outside air side thermal resistance R3 can be adjusted by the adjustment unit 20D. Furthermore, the outside air side thermal resistance R3 and the heat capacity C3 of the target position P3 may be calculated based on a predetermined formula, or values ​​corresponding to the external temperature, the rotation speed of the internal combustion engine, etc. may be selected from table data stored in the memory area.

[0088] The heat flow at the target position P3 is expressed by the following mathematical formula (4).

number

[0089] P*Δt is the amount of heat flowing into the target position P3 of the heating target 11, and ((-T3+T a ) / R3)*Δt is the amount of heat flowing from the target position P3 to the outside of the heating target 11, and C3*(T 3Δt -T3) is the amount of heat accumulated at the target position P3. From the formula shown in Equation 4, the calculation unit 20C calculates the temperature T at the target position P3 after the lapse of a predetermined short time Δt. 3Δt is the supply power P, the current temperature T3 at the target position P3, the outside air thermal resistance R3 from the target position P3 to the outside air of the heating target 11, the heat capacity C3 at the target position P3, and the outside air temperature T a It is estimated based on the following.

[0090] For example, in the second embodiment, when the start switch (for example, the ignition switch) of the vehicle in which the in-vehicle system 100 is installed is in the OFF state, T3=T aThis formula is valid when the temperature of the object to be heated 11 has dropped sufficiently after the start switch has been kept in the OFF state for a long time. Therefore, when the calculation unit 20C first executes the calculation of Equation 4, T3=T a By operating as 3Δt T a The value detected by the outside air temperature acquisition unit 20E before the internal combustion engine is started is used for T. Then, when the calculation unit 20C executes the calculation of Equation 4 in the next period, the previously calculated T 3Δt By substituting into T3, T after another Δt has elapsed 3Δt In this way, the calculation unit 20C calculates the supply power P and the outside air temperature T a The calculation of Equation 4 is repeated at predetermined intervals (for example, every Δt) based on the detection result of the outside air temperature acquisition unit 20E. Then, the calculation unit 20C calculates the temperature T 3Δt The estimation operation is performed to sequentially estimate

[0091] As in the first embodiment, the adjusting unit 20D adjusts the temperature of the outside air T a and the flow rate V of the gas flowing into the heating object 11 P The calculation unit 20C then uses the outdoor air side thermal resistance R3 adjusted by the adjustment unit 20D to estimate the temperature at the target position P3.

[0092] The calculation unit 20C of the in-vehicle temperature estimation device 130 calculates the temperature at the target position P3 after a predetermined short time Δt has elapsed, based on the supplied power P, the current temperature T3 at the target position P3, the outside air side thermal resistance R3 from the target position P3 to the outside air of the heating target 11, the heat capacity C3 at the target position P3, and the outside air temperature T a According to this configuration, it is possible to know in advance the temperature at the target position P3 after a predetermined short time Δt has elapsed, and it is possible to control the actual temperature at the target position P3 so that it does not reach a temperature that should be avoided.

[0093] <Other embodiments> The present disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of features of the above-described or following embodiments is possible within a range that does not contradict. Furthermore, any feature of the above-described or following embodiments may be omitted unless explicitly stated as essential. Furthermore, the above-described embodiment may be modified as follows.

[0094] Unlike the first embodiment, the outside air temperature acquisition unit may be configured to detect the resistance value of the object to be heated immediately after the start of power supply. For example, the outside air temperature acquisition unit detects the resistance value of the object to be heated by dividing the voltage value detected by the voltage detection unit by the current value detected by the current detection unit. The temperature determination unit stores the NTC characteristics of the object to be heated in the form of table data. This table data associates the resistance value of the object to be heated calculated by the outside air temperature acquisition unit with the temperature value of the object to be heated corresponding to this value. Here, "immediately after the start of power supply" refers to, for example, immediately after the supply of power to the object to be heated begins.

[0095] For example, the outside air temperature acquisition unit calculates the resistance value of the heating target immediately after the supply of power to the heating target begins from the current value and voltage value input from the current detection unit and voltage detection unit immediately after the supply of power to the heating target begins.The temperature determination unit then determines the temperature of the heating target immediately after the supply of power to the heating target begins based on the calculated value (resistance value) and the NTC characteristics of the heating target stored in the temperature determination unit.The temperature determined at this time is used as the outside air temperature.In other words, the outside air temperature includes the resistance value of the heating target immediately after the start of power supply.The calculation unit then estimates the temperature of the target location based on the supplied power and the outside air temperature including the resistance value of the heating target.This configuration makes it possible to estimate the temperature of the target location without using a configuration that directly measures the outside air temperature.

[0096] Unlike the first embodiment, the temperature at each target position may be estimated using a thermal circuit model in which three or more target positions are connected together.

[0097] Unlike the first embodiment, the temperature estimation device may be used to estimate the temperature of a member other than the EHC as the heating target. In this case, the calculation unit performs estimation based on a thermal circuit model newly constructed according to the target member.

[0098] Unlike the first embodiment, the adjustment unit may be configured to adjust the outside air side thermal resistance based on either the temperature of the outside air or the flow rate of the gas flowing into the heating target.

[0099] Unlike the first embodiment, an outside air temperature acquisition unit may be provided on the electrode plate or on the outer peripheral surface of the object to be heated, and the temperatures at these positions may be used as temperatures at positions different from the target position outside the object to be heated.

[0100] Unlike the first embodiment, the current temperature at the second target position may be detected by a temperature sensor, and the temperature at the first target position may be estimated using this detected value. That is, the temperature at the first target position may be estimated using the temperature of the outside air and the temperature at the second target position (a different position on the heating target from the target position).

[0101] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope indicated by the claims or within the scope equivalent to the claims. [Explanation of symbols]

[0102] 10...Power supply section 10A…Power supply side conductive path 11...Heated object 11A...Resistance section 11B…Electrode plate 12…Power line 13...DCDC converter (drive unit) 14...Current detection section 15...Voltage detection section 20...Power control unit 20A...Power detection section 20B…Temperature identification part 20C...Calculation section 20D…Adjustment section 20E…Outside temperature acquisition section 30,130…Temperature estimation device 60…External ECU 100...In-vehicle systems A…Area Ac: The amount of change in the resistance of the resistor when the temperature changes by a certain amount Ad...Adjustment value B...Variation C…Central characteristic C1…inner heat capacity C2: Heat capacity at the first target position C3: Heat capacity at the target position Cm...Thermal circuit model D…lower limit characteristic E: Voltage value G...Reference conductive path I...Current value Ms…Temperature maintenance signal P…supply power P1: Second target position (target position) P2: First target position (target position) P3: Target position R1: Internal thermal resistance R2, R3...Outside air thermal resistance Rd: Resistance value at the lower limit R E …Rotation speed Rm…Temperature maintenance area Ru: Resistance value at the upper limit characteristic S…Slight change area S1, S2, S3, S4...Temperature of the heated object Si: On / off signal T1: Current temperature at the second target location T2: Current temperature at the first target position T3: Current temperature of the target location T 1Δt ...Temperature at the second target position after a predetermined time has elapsed T 2Δt ...Temperature at the first target position after a specified time has elapsed T 3Δt ...Temperature at the target location after a specified time has elapsed Ta …Outside air temperature U...upper limit characteristic V P ...Exhaust gas flow rate of an internal combustion engine h...Convection heat transfer coefficient r G …Volume ratio Δt...predetermined minute time (predetermined time)

Claims

1. It is applied to heating objects in vehicles that are heated by passing electricity. a power detection unit that detects power supplied to the heating object; a calculation unit that performs calculations to estimate a temperature at a target position on the heating target; a temperature specifying unit that specifies an outside air temperature outside the heating target; and the calculation unit performs a calculation to estimate a temperature at the target position based on the supplied power detected by the power detection unit and the outside air temperature identified by the temperature identification unit; performing a calculation to estimate temperatures at the plurality of target positions on the heating target based on the supplied power and the outside air temperature; a temperature of a first target position among the plurality of target positions after a predetermined time has elapsed is estimated based on a current temperature of the first target position, an outside air thermal resistance from the first target position to the outside air of the heating target, a heat capacity of the first target position, a current temperature of a second target position among the plurality of target positions that is different from the first target position, an inside thermal resistance from the first target position to the second target position, and the temperature of the outside air; An in-vehicle temperature estimation device that estimates the temperature at the second target position after a predetermined time has elapsed based on the supplied power, the current temperature at the first target position, the current temperature at the second target position, the internal thermal resistance from the second target position to the first target position, and the internal heat capacity at the second target position.

2. Applied to an in-vehicle heating object that is heated by passing electricity, a power detection unit that detects power supplied to the heating object; a calculation unit that performs calculations to estimate a temperature at a target position on the heating target; a temperature specifying unit that specifies an outside air temperature outside the heating target; and The calculation unit performs calculations to estimate the temperature of the target location based on the supplied power detected by the power detection unit and the outside air temperature identified by the temperature identification unit, and estimates the temperature of the target location after a predetermined time has elapsed based on the supplied power, the current temperature of the target location, the outside air thermal resistance from the target location to the outside air of the heating target, the heat capacity of the target location, and the outside air temperature.

3. Applied to an in-vehicle heating object that is heated by passing electricity, a power detection unit that detects power supplied to the heating object; a calculation unit that performs calculations to estimate a temperature at a target position on the heating target; a temperature specifying unit that specifies an outside air temperature outside the heating target; and the calculation unit performs a calculation to estimate a temperature at the target position based on the supplied power detected by the power detection unit and the outside air temperature identified by the temperature identification unit; The heating target is configured to operate by receiving power supply from a driving unit, a power control unit for controlling the drive unit; the power control unit generates a temperature maintenance signal that controls the operation of the drive unit so as to maintain the temperature of the target position within a temperature range of a predetermined temperature maintenance region based on the calculation result of the calculation unit; the heating target has an NTC characteristic in which the resistance value decreases as the temperature of the heating target increases within a predetermined temperature range, the NTC characteristic has a small change region in which the temperature characteristic of the resistance value of the heating object is smaller than the variation in the resistance value, The calculation unit is an in-vehicle temperature estimation device that performs calculations to estimate the temperature of the target position at least when the temperature of the heating target is in the temperature maintenance region and the slight change region.

4. the temperature of the outside air includes the temperature of the inflow gas flowing into the heating target, the temperature specifying unit detects the temperature of the inflow gas; The in-vehicle temperature estimation device according to claim 1 , wherein the calculation unit performs calculations to estimate the temperature of the target position based on the supplied power and the temperature of the inflowing gas.

5. An on-board temperature estimation device as described in claim 1, further comprising an adjustment unit that adjusts the outside air side thermal resistance based on at least one of the temperature of the outside air or the flow rate of the outside air flowing into the object to be heated.

6. An on-board temperature estimation device as described in any one of claims 1 to 3, wherein the object to be heated is an EHC arranged in the exhaust path of gas emitted from an internal combustion engine.

7. the heating target is an EHC disposed in an exhaust path of gas exhausted from an internal combustion engine, The vehicle-mounted temperature estimation device according to claim 5 , wherein the adjustment unit adjusts the outside air-side thermal resistance based on the rotation speed of the internal combustion engine.

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