Cooling water deterioration estimation system

Abstract

To accurately estimate deterioration of cooling water.SOLUTION: A control device 100 executes acquisition processing for acquiring data on a heat reception history of cooling water. A data analysis device 300 executes: estimation processing for receiving the data on the heat reception history from the control device 100 and estimating deterioration of the cooling water; and heat reception history estimation processing for estimating the heat reception history of the cooling water during stop of an operation of the control device 100 on the basis of stop time information including a temperature of the cooling water and an outside air temperature when the operation of the control device 100 is stopped during stop of an engine.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cooling water deterioration estimation system. [Background technology]

[0002] The coolant for an internal combustion engine deteriorates depending on its heat history. For this reason, for example, a device described in Patent Document 1 is designed to estimate the deterioration of the coolant depending on the temperature state of the coolant. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 107990 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even after the operation of the internal combustion engine is stopped, the coolant remains at a high temperature for a while. Therefore, the deterioration of the coolant progresses even while the internal combustion engine is stopped. Here, if the operation of the control device is stopped when the engine is stopped, the temperature of the coolant during the stop cannot be obtained, which may reduce the accuracy of the estimation of the deterioration of the coolant. [Means for solving the problem]

[0005] The cooling water deterioration estimation system that solves the above problem is a system that estimates the deterioration of the cooling water of an internal combustion engine. This deterioration estimation system includes an execution device. This execution device includes: During operation of the execution device an acquisition process for acquiring data relating to the heat receiving history of the cooling water; 、 a heat reception history estimation process for estimating a heat reception history of the cooling water while the execution device is stopped based on stop time information including the temperature of the cooling water and an outside air temperature at the time the execution device is stopped when the engine is stopped; an estimation process for estimating the deterioration based on data relating to the heat reception history of the cooling water while the execution device is in operation and the heat reception history of the cooling water while the execution device is not in operation; Execute.

[0006] According to this configuration, the heat reception history estimation process is executed to estimate the heat reception history of the coolant even when the operation of the executing device is stopped. Then, the deterioration of the coolant is estimated based on data including the heat reception history of the coolant during the operation stoppage. In this way, the deterioration is estimated taking into account the heat reception history of the coolant during the operation stoppage of the executing device, thereby improving the accuracy of the estimation of the deterioration of the coolant. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram illustrating a configuration of a deterioration estimation system according to an embodiment. [Figure 2] 4 is a flowchart showing a procedure of a process executed by the control device of the embodiment. [Figure 3] 4 is a graph showing temperature divisions and counter values ​​according to the embodiment; [Figure 4] 4 is a graph showing the relationship between temperature ranges and coolant temperatures according to the embodiment; [Figure 5] 4 is a flowchart showing a procedure of a process executed by the control device of the embodiment. [Figure 6] 4 is a flowchart showing the procedure of a process executed by the data analysis device of the embodiment. [Figure 7] 4 is a graph showing temperature divisions and conversion counter values ​​according to the embodiment; [Figure 8] 4 is a flowchart showing the procedure of a process executed by the data analysis device of the embodiment. [Figure 9] 4 is a flowchart showing the procedure of a process executed by the data analysis device of the embodiment. [Figure 10] 4 is a flowchart showing the procedure of a process executed by the data analysis device of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] <System configuration> Hereinafter, an embodiment in which a coolant deterioration estimation system is applied to an internal combustion engine mounted on a vehicle will be described with reference to FIGS.

[0014] As shown in Fig. 1, a vehicle 500 includes an internal combustion engine 15 and a cooling device 10. The cooling device 10 is a device that cools the internal combustion engine 15 with cooling water. A rust inhibitor and the like are added to this cooling water.

[0015] The cooling device 10 includes a radiator 12, which is a heat exchanger. A water jacket 15W is formed inside the cylinder block or cylinder head of an internal combustion engine 15. A first passage 16 connects the coolant outlet of the water jacket 15W to the coolant inlet of the radiator 12. A second passage 17 connects the coolant inlet of the water jacket 15W to the coolant outlet of the radiator 12. A water pump 18 is provided on the path of the second passage 17.

[0016] The cooling device 10 includes a branch passage 20 that branches off from the first passage 16 and is connected to a second passage 17 between the cooling water outlet of the radiator 12 and the water pump 18. A thermostat 25 is disposed at the connection between the branch passage 20 and the second passage 17. The thermostat 25 is a control valve in which the opening degree of a valve body provided therein changes depending on the temperature of the coolant, and when the temperature of the coolant is low, the coolant flowing out of the water jacket 15W is returned so as to flow through the branch passage 20 rather than the radiator 12. On the other hand, when the temperature of the coolant is high, the coolant flowing out of the water jacket 15W is returned so as to flow through the radiator 12 rather than the branch passage 20.

[0017] The control device 100 performs various controls such as the intake air amount and injected fuel amount of the internal combustion engine 15. The control device 100 includes a central processing unit (hereinafter referred to as CPU) 110, a memory 120 storing control programs and data, and a communication device 130. The control device 100 performs various controls by the CPU 110 executing the programs stored in the memory 120. The control device 100 is also capable of communicating with a data analysis device 300 via an external network 200 via the communication device 130. In this embodiment, the control device 100 including the CPU 110 and the memory 120 constitutes a first execution device.

[0018] When performing various controls, the control device 100 refers to various detection values ​​obtained from sensors, etc. For example, the control device 100 refers to a coolant temperature THW, which is the temperature of the coolant, detected by a water temperature sensor 34, and an outside air temperature THout, which is detected by an outside air temperature sensor 35.

[0019] The data analysis device 300 analyzes data transmitted from a plurality of vehicles 500, vehicles 600, etc. The data analysis device 300 includes a CPU 310, a memory 320, a communication device 330, etc., which are capable of communicating via a network 200. In this embodiment, the data analysis device 300 including the CPU 310 and the memory 320 constitutes a second execution device.

[0020] <Calculating the degree of deterioration of cooling water> The coolant for the internal combustion engine 15 deteriorates due to oxidation depending on the heat reception history, which is represented by the heat reception temperature and heat reception time. As the deterioration progresses in this manner, the effectiveness of additives such as rust inhibitors decreases. Therefore, in this embodiment, the deterioration of the coolant is estimated by calculating the deterioration degree R of the coolant.

[0021] In this embodiment, the larger the value of the deterioration degree R, the more advanced the deterioration. Furthermore, the hydrogen ion concentration (so-called pH) and electrical conductivity of the coolant are used as physical quantities for determining the degree of deterioration in tests, etc. Furthermore, for verification with an actual vehicle, for example, analysis of the remaining components in the coolant and investigation of the state of rust in the recovered cooling device are also performed.

[0022] The calculation of the deterioration level R will be explained below. Fig. 2 shows the procedure of the process executed by the control device 100. The process shown in Fig. 2 is realized by the CPU 110 executing a program stored in the memory 120. The process shown in Fig. 2 is executed when the engine is started. In the following, step numbers are represented by numbers preceded by "S."

[0023] When this process starts, the CPU 110 transmits a vehicle ID, which is identification information of the vehicle 500, start-up information, and stop-up information to the data analysis device 300 (S10). The start-up information includes, for example, an operation start water temperature THWs, which is the cooling water temperature THW at the time when the control device 100 starts operation at the current engine start, and an operation start time Ts, which is the time when the operation starts.

[0024] The shutdown information also includes, for example, the shutdown water temperature THWe, which is the cooling water temperature THW at the time when the control device 100 shuts down the engine immediately before the engine is shut down, and the operation shutdown time Te, which is the time of the shutdown. The shutdown information also includes, for example, the operation shutdown outside air temperature THoute, which is the outside air temperature THout at the time when the control device 100 shuts down.

[0025] Next, the CPU 110 starts a process of acquiring operating temperature information (S12) and ends this process. The operating temperature information is the cumulative time for each temperature of the coolant temperature THW while the internal combustion engine 15 is operating, that is, while the control device 100 is operating. In this embodiment, the cumulative time for each temperature of the coolant temperature THW is a value indicating the heat reception history of the coolant.

[0026] FIG. 3 shows an example of the cumulative time for each temperature of the cooling water temperature THW acquired in the acquisition process. In this embodiment, a plurality of temperature ranges are set, and the cumulative time for each temperature range of the cooling water temperature THW is represented by a counter value Cn indicating the cumulative time for each temperature range. The counter value Cn is a value calculated for each temperature range described below, and the number "n" indicates the corresponding temperature range. Incidentally, the counter value Cn can also be converted into the cumulative time for each temperature range by multiplying the counter value Cn by the sampling period of the cooling water temperature THW.

[0027] In this embodiment, ten temperature sections are set, which are, in order from lowest to highest temperature, a first temperature section TR1, a second temperature section TR2, a third temperature section TR3, a fourth temperature section TR4, a fifth temperature section TR5, a sixth temperature section TR6, a seventh temperature section TR7, an eighth temperature section TR8, a ninth temperature section TR9, and a tenth temperature section TR10.

[0028] The first temperature section TR1 is a temperature range below a predetermined first water temperature THW1. The counter value Cn for this first temperature section TR1 is referred to as a first counter value C1. The second temperature section TR2 is a temperature range equal to or higher than the first water temperature THW1 and lower than the second water temperature THW2. The counter value Cn for this second temperature section TR2 is referred to as a second counter value C2.

[0029] The third temperature section TR3 is a temperature range equal to or higher than the second water temperature THW2 and lower than the third water temperature THW3. The counter value Cn for this third temperature section TR3 is referred to as a third counter value C3. The fourth temperature section TR4 is a temperature range equal to or greater than the third water temperature THW3 and less than the fourth water temperature THW4. The counter value Cn for this fourth temperature section TR4 is referred to as a fourth counter value C4. This fourth temperature section TR4 is the section to which the reference temperature THWb, which will be described later, belongs.

[0030] The fifth temperature section TR5 is a temperature range equal to or higher than the fourth water temperature THW4 and lower than the fifth water temperature THW5. The counter value Cn for this fifth temperature section TR5 is referred to as a fifth counter value C5. The sixth temperature section TR6 is a temperature range equal to or higher than the fifth water temperature THW5 and lower than the sixth water temperature THW6. The counter value Cn for this sixth temperature section TR6 is referred to as a sixth counter value C6.

[0031] The seventh temperature section TR7 is a temperature range equal to or higher than the sixth water temperature THW6 and lower than the seventh water temperature THW7. The counter value Cn for this seventh temperature section TR7 is referred to as a seventh counter value C7. The eighth temperature section TR8 is a temperature range equal to or higher than the seventh water temperature THW7 and lower than the eighth water temperature THW8. The counter value Cn for this eighth temperature section TR8 is referred to as an eighth counter value C8.

[0032] The ninth temperature section TR9 is a temperature range equal to or higher than the eighth water temperature THW8 and lower than the ninth water temperature THW9. The counter value Cn for this ninth temperature section TR9 is referred to as a ninth counter value C9. The tenth temperature section TR10 is a temperature range equal to or higher than the ninth water temperature THW9. The counter value Cn for this tenth temperature section TR10 is referred to as a tenth counter value C10.

[0033] Figure 4 shows the relationship between temperature categories and cooling water temperatures. Coolant for internal combustion engines deteriorates when ethylene glycol, one of its components, is decomposed by heat and turns into formic acid or glycolic acid, becoming acidic. The higher the coolant temperature, the more likely the coolant is to deteriorate. Therefore, the coolant temperature THW and the deterioration level R are correlated. When the functional equation showing the relationship between the coolant temperature THW and the deterioration level R is used as a deterioration function, the deterioration level R increases as the coolant temperature THW increases.

[0034] It is known that the deterioration level of the coolant follows the 10°C doubling rule, which is the Arrhenius law. Therefore, for example, the deterioration level R when the coolant temperature THW is 90°C is set to a dimensionless value of "100." Then, the deterioration function formula can be the following function formula (1) f(THW) with the coolant temperature THW as an input variable.

[0035] R=f(THW)=100×2^{(THW-90) / 10}…(1) In this embodiment, when the number of temperature sections to be set is n and the deterioration level R at a predetermined coolant temperature is set as the deterioration level reference value Rhi, the deterioration level reference value Rhi is equally divided by the value of "n-1." Then, the coolant temperatures corresponding to each equally divided deterioration level R are calculated from the above deterioration function formula, and each calculated coolant temperature is set as a boundary value of each temperature section.

[0036] As an example, in this embodiment, 10 temperature sections are set. Therefore, "10" is substituted for the above "n." Furthermore, the maximum allowable coolant temperature THWhi expected during normal use is set as the default coolant temperature. Then, the deterioration degree R corresponding to this maximum allowable temperature THWhi is calculated from the above deterioration function formula, and the calculated value is set as the deterioration degree reference value Rhi.

[0037] Next, the deterioration level reference value Rhi is equally divided by "9", which is the value of "n-1". These equally divided deterioration levels are, in ascending order of value, the first deterioration level R1, the second deterioration level R2, the third deterioration level R3, the fourth deterioration level R4, the fifth deterioration level R5, the sixth deterioration level R6, the seventh deterioration level R7, the eighth deterioration level R8, and the ninth deterioration level R9. Note that the ninth deterioration level R9 is the same as the deterioration level reference value Rhi.

[0038] Then, the coolant temperature corresponding to each equally divided deterioration degree R is calculated from the above deterioration function formula. That is, where "n=1 to 9", the coolant temperature THW corresponding to the n-th deterioration degree Rn is calculated from the above deterioration function formula, and the calculated value is set as the n-th coolant temperature THWn.

[0039] More specifically, the coolant temperature THW corresponding to the first deterioration degree R1 is calculated from the deterioration function equation, and the calculated value is set as the first coolant temperature THW1. Further, the coolant temperature THW corresponding to the second deterioration degree R2 is calculated from the deterioration function equation, and the calculated value is set as the second coolant temperature THW2.

[0040] Further, the coolant temperature THW corresponding to the third deterioration degree R3 is calculated from the deterioration function equation, and the calculated value is set as the third coolant temperature THW3. Furthermore, the coolant temperature THW corresponding to the fourth deterioration degree R4 is calculated from the deterioration function equation, and the calculated value is set as the fourth coolant temperature THW4.

[0041] Furthermore, the cooling water temperature THW corresponding to the fifth deterioration degree R5 is calculated from the deterioration function equation, and the calculated value is set as the fifth water temperature THW5. Furthermore, the coolant temperature THW corresponding to the sixth deterioration degree R6 is calculated from the deterioration function equation, and the calculated value is set as the sixth coolant temperature THW6.

[0042] Furthermore, the coolant temperature THW corresponding to the seventh deterioration degree R7 is calculated from the deterioration function equation, and the calculated value is set as the seventh coolant temperature THW7. Furthermore, the coolant temperature THW corresponding to the eighth deterioration degree R8 is calculated from the deterioration function equation, and the calculated value is set as the eighth coolant temperature THW8.

[0043] The allowable maximum temperature THWhi is set to the ninth water temperature THW9. In this way, the n-th water temperature THWn is set as a boundary value that divides the first temperature division TR1 to the tenth temperature division TR10. By adopting such a method of setting the temperature divisions, in this embodiment, as shown in Fig. 4, the temperature divisions are subdivided as the temperature range increases where the coolant is more likely to deteriorate.

[0044] When the process of S12 described above starts, the CPU 110 acquires the coolant temperature THW at every predetermined sampling period. Then, while the control device 100 is operating, the CPU 110 repeatedly executes a process of incrementing the counter value Cn of the temperature section to which the acquired coolant temperature THW belongs by a predetermined value α (for example, 1). This updates the counter value Cn, which corresponds to the cumulative time for each temperature of the coolant temperature THW, for each temperature section. Then, the updated counter values ​​Cn are stored in the memory 120.

[0045] FIG. 5 shows the procedure of the process executed by the control device 100 at predetermined intervals. When this process starts, the CPU 110 determines whether there is a request to transmit operating temperature information (S20). For example, if a predetermined period has elapsed since the previous transmission of operating temperature information, the CPU 110 determines that there is a request to transmit operating temperature information. Examples of the predetermined period include the operating time of the control device 100 and the mileage of the vehicle 500.

[0046] If it is determined that there is a request to transmit the operating temperature information (S20: YES), the CPU 110 transmits the vehicle ID, which is identification information of the vehicle 500, and the counter value Cn for each temperature category that constitutes the operating temperature information, to the data analysis device 300 (S22). Note that if the CPU 110 completes the processing of S22 or makes a negative determination in the processing of S20, it temporarily ends the series of processing shown in FIG.

[0047] <Processing Executed by Data Analysis Device 300> FIG. 6 shows the procedure of the process executed by the CPU 310 when the data analyzing device 300 receives the data transmitted in the process of S22 shown in FIG.

[0048] In S100, when the CPU 310 receives the vehicle ID and the counter value Cn, which is the operating temperature information, transmitted from the control device 100, the CPU 310 executes the process of S110. The process of S110 is a process of updating each counter value Cn for each temperature category that is stored in the memory 320 in association with the vehicle ID, and storing the updated counter value Cn in the memory 320. This update of the counter value Cn is performed by adding the received counter value Cn to each counter value Cn for each temperature category that is stored in the memory 320. As a result of this update, the value of each counter value Cn for each temperature category that is stored in the memory 320 becomes the integrated value of the counter values ​​Cn for each temperature category that have been received up to that point.

[0049] Next, the CPU 310 executes a conversion process to convert each updated counter value Cn into a converted counter value CCn (S120). The converted counter value CCn is a converted value obtained by converting each counter value Cn for each temperature category into a counter value Cn corresponding to the accumulated time at a predetermined reference temperature THWb (for example, approximately 90°C). In other words, the converted counter value CCn is a value obtained by converting the counter value Cn for each temperature category into a counter value assuming that the coolant temperature THW is the reference temperature THWb. In other words, when the deterioration level corresponding to the counter value Cn for each temperature category is the deterioration level Rn, the converted counter value CCn is the counter value Cn required to reach the deterioration level Rn at the reference temperature THWb. Note that the number "n" in the converted counter value CCn is the same as the number "n" in the counter value Cn from which the conversion is made and indicates the corresponding temperature category.

[0050] This conversion process is performed as follows. As shown in Figure 7, first, for each of the first temperature division TR1 to the tenth temperature division TR10, the representative temperatures of the temperature divisions, namely the first representative temperature P1, the second representative temperature P2, the third representative temperature P3, the fourth representative temperature P4, the fifth representative temperature P5, the sixth representative temperature P6, the seventh representative temperature P7, the eighth representative temperature P8, the ninth representative temperature P9, and the tenth representative temperature P10, are determined in advance. Note that, hereinafter, these representative temperatures are collectively referred to as representative temperature Pn. Furthermore, "n" is substituted with a number indicating the temperature division.

[0051] The second representative temperature P2 to the ninth representative temperature P9 are calculated from the following formula (2). Note that any value between 2 and 9 is substituted for "n" in formula (2). Furthermore, the coefficient K is a value greater than "0" and less than "1", and is preset to an optimum value for reducing the error in the degradation degree R.

[0052] Pn=THW(n-1)+(THWn-THW(n-1) ) × coefficient K… (2) For example, when the coefficient K is "0.4", the second representative temperature P2, which is the representative temperature of the second temperature section TR2, is calculated as "first water temperature THW1 + (second water temperature THW2 - The value is calculated by multiplying the first water temperature (THW1) by 0.4.

[0053] Furthermore, the first representative temperature P1 and the tenth representative temperature P10 are preset to temperatures that are optimal for reducing the error in the degradation degree R. The lower the coolant temperature THW, the less likely the coolant will deteriorate. Therefore, as shown in Figure 7, in temperature sections where the representative temperature Pn is lower than the reference temperature THWb, the counter value Cn is converted so that the converted counter value CCn (shown by the solid line) is smaller than the counter value Cn before conversion (shown by the two-dot chain line). Also, the higher the coolant temperature THW, the more likely the coolant will deteriorate. Therefore, as shown in Figure 7, in temperature sections where the representative temperature Pn is higher than the reference temperature THWb, the counter value Cn is converted so that the converted counter value CCn (shown by the solid line) is larger than the counter value Cn before conversion (shown by the two-dot chain line).

[0054] The calculation of the conversion counter value CCn for each temperature category is performed using a function that takes the representative temperature Pn calculated for each temperature category and the counter value Cn of the temperature category to which the representative temperature Pn belongs as input and outputs the conversion counter value CCn.

[0055] Next, the CPU 310 calculates the sum S by adding up all the values ​​of the conversion counter values ​​CCn calculated for each temperature section (S130). Next, CPU 310 executes a calculation process to calculate the degradation level R based on the calculated sum S (S140). Here, a relational expression between the sum S and the degradation level R is determined in advance, and CPU 310 calculates the degradation level R based on this relational expression. Note that the degradation level R is calculated so that the larger the value of the sum S, the larger the value of the degradation level R. After calculating the degradation level R in this way, CPU 310 stores the calculated degradation level R in memory 320 (S150).

[0056] Next, CPU 310 executes a process of calculating an expected coolant replacement time based on the amount of change in deterioration level R (S160). In S160, CPU 310 performs the following process, for example. That is, CPU 310 calculates the difference between the deterioration level R calculated last time and the deterioration level R calculated this time. CPU 310 also calculates the period (e.g., elapsed time or mileage) from when the deterioration level R was calculated last time to when the deterioration level R is calculated this time. Then, based on the calculated difference and the elapsed period, CPU 310 calculates the time or mileage until the deterioration level R reaches an allowable limit value. Then, the calculated time or mileage is set as the expected replacement time. When the process of S160 is completed, CPU 310 ends this process.

[0057] <About heat reception history estimation processing> FIG. 8 shows the procedure of the process executed by CPU 310 when data analysis device 300 receives the data transmitted in the process of S10 shown in FIG.

[0058] In S200, when the vehicle ID, start-up information, and shutdown information transmitted from the control device 100 are received, the CPU 310 then executes the process of S210. The process of S210 is a heat reception history estimation process that estimates the heat reception history of the coolant while the control device 100 is stopped based on the shutdown information, that is, a process that calculates each counter value Cn for each temperature category while the control device 100 is stopped based on the shutdown information.

[0059] In the process of S210, the counter values ​​Cn during the operation suspension are calculated as follows. First, after the engine is stopped, according to the law of heat dissipation, the amount of heat dissipated from the coolant temperature is large at first, resulting in a large drop in temperature. Then, the rate of temperature drop slows down, and the temperature eventually converges to the ambient temperature, i.e., the outside air temperature. Therefore, the inventors have confirmed that the coolant temperature THW(t) at the elapsed time t after the engine is stopped can be calculated from the function shown in the following equation (3) based on the coolant temperature THWe at the time of engine shutdown and the outside air temperature THoute at the time of engine shutdown, which are included in the engine shutdown information.

[0060]

number

[0061] Furthermore, the elapsed time tx until the coolant temperature THW reaches a certain temperature THWx can be calculated from the function shown in the following equation (4), which is a modification of equation (3). Note that "log" in each of the following equations is the natural logarithm with base "e".

[0062]

number

[0063]

number

[0064]

number

[0065] Furthermore, when calculating the cumulative time T1 in the first temperature section TR1, the value obtained by subtracting a predetermined value (for example, a value of approximately 10°C to 20°C) from the first water temperature THW1 is substituted for the value of "THW(n-1)" in equation (5).

[0066] The stop time Tsp, which is the time during which the control device 100 has stopped operating, can be calculated by subtracting the operation stop time Te included in the stop information from the operation start time Ts included in the start information. The constant A can be calculated based on the following equation (7), which is obtained by substituting the stop time Tsp for the elapsed time t in equation (3) and substituting the operation start water temperature THWs included in the start information for the cooling water temperature THW(t).

[0067]

number

[0068] 9 and 10 show the procedure for calculating the counter value Cn during operation suspension. When this process starts, the CPU 310 calculates the stop time Tsp, which is the time during which the control device 100 has stopped operating, by subtracting the operation stop time Te included in the stop information from the operation start time Ts included in the start information.

[0069] Next, CPU 310 determines whether stop time Tsp is a value within a range greater than or equal to threshold A and less than or equal to threshold B (S310). This determination process at S310 is executed for the following reason. That is, if stop time Tsp is excessively short or excessively long, the deviation between the estimated value and the actual value of the coolant temperature may become large. If the deviation between the estimated value and the actual value of the coolant temperature becomes large, the deviation between the estimated counter value Cn during the operation shutdown and the counter value Cn corresponding to the actual change in the coolant temperature may become large. If such a deviation occurs, the accuracy of constant A may be reduced if constant A is calculated in the process at S340 described below. Therefore, in order to calculate constant A when stop time Tsp is a value within a predetermined range and is a time suitable for calculating constant A, determination process for stop time Tsp is executed in the process at S310. Therefore, for the threshold value A and the threshold value B, upper and lower limit values ​​of the stop time Tsp that enable the constant A to be calculated with high accuracy are set in advance.

[0070] If the CPU 310 determines in the process of S310 that the stop time Tsp is a value within the range of greater than or equal to threshold A and less than or equal to threshold B (S310: YES), the CPU 310 determines whether the water temperature at the start of operation THWs is higher than the outside air temperature at the time of operation stop THoute (S320). If the CPU 310 determines that the water temperature at the start of operation THWs is higher than the outside air temperature at the time of operation stop THoute (S320: YES), the CPU 310 executes the calculation process of S340. 0's The calculation process is a process of calculating the constant A by substituting the shutdown time Tsp, the water temperature at the start of operation THWs, the water temperature at the shutdown of operation THWe, and the outside air temperature at the shutdown of operation THoute into the above equation (7).

[0071] On the other hand, if it is determined in the process of S320 that the water temperature at the start of operation THWs is equal to or lower than the outside air temperature at shutdown THOUTE (S320: NO), the CPU 310 executes a process to correct the outside air temperature at shutdown THOUTE (S330). In the process of S330, the CPU 310 executes a process to reduce the value of the outside air temperature at shutdown THOUTE by subtracting a predetermined value from the acquired outside air temperature at shutdown THOUTE. This process is a measure to avoid the inability to calculate log when the value of "THWs-THoute" in the function formula (7) becomes a negative value when calculating the constant A in the process of S340.

[0072] After performing the process of S330, the CPU 310 calculates the constant A in the process of S340. Next, CPU 310 executes a process to update constant A (S350). In this process of S350, CPU 310 calculates the arithmetic mean of multiple constants A, including the constant A calculated in the current process and multiple constants A calculated most recently. Then, CPU 310 updates constant A by substituting the calculated arithmetic mean value for constant A.

[0073] When the process of S350 is completed or when a negative determination is made in the process of S310, the CPU 310 executes the process of S350 shown in FIG. 400 Execute the following process. As shown in Figure 10, S 400 As part of this process, the CPU 310 resets the cumulative time T(n) for each temperature range (n) to 0. Note that "n" is a value that represents the temperature range and can take a value from 1 to 10.

[0074] Next, the CPU 310 determines the temperature category (n) to which the operation-stopped water temperature THWe obtained through the process of S10 shown in FIG. 2 belongs (S410). Next, the CPU 310 calculates the cumulative time T(n) in the temperature section (n) determined in the process of S410 based on the above formula (5) (S420).

[0075] Next, the CPU 310 executes a process of updating the integrated cumulative time ST (S430). The integrated cumulative time ST is an integrated value of the cumulative time T(n), and its initial value is "0." The CPU 310 updates the integrated cumulative time ST by adding the cumulative time T(n) calculated in the process of S420 to the previous value of the integrated cumulative time ST.

[0076] Next, CPU 310 determines whether the updated integrated cumulative time ST is shorter than the stop time Tsp (S440). If it determines that the updated integrated cumulative time ST is shorter than the stop time Tsp (S440: YES), CPU 310 executes a process of decreasing the value of "n" by 1 in order to change the temperature category for calculating the cumulative time T(n) (S450). This process of S450 is a preprocessing for changing the temperature category for calculating the cumulative time T(n) to a temperature category that is one step lower.

[0077] Next, CPU 310 determines whether the value of "n" updated in the process of S450 is "0" (S460). If it determines that the value of "n" is not "0" (S460: NO), CPU 310 repeatedly executes the processes from S420 onward to calculate the cumulative time T(n) for each temperature section (n).

[0078] If it is determined in the processing of S440 that the integrated cumulative time ST is equal to or greater than the stop time Tsp (S440: NO), the CPU 310 calculates the cumulative time T(n) of the temperature category (n) corresponding to the "n" updated in the processing of S450 based on the following formula (8).

[0079] T(n)=stop time Tsp-ST-T(n)…(8) Note that "ST" on the right side of equation (8) is the integrated cumulative time ST after being updated in the processing of S430. Also, "T(n)" on the right side of equation (8) is the cumulative time T(n) calculated in the processing of S420. Therefore, the value of "ST-T(n)" in equation (8) is equal to the value of the integrated cumulative time ST before being updated in the processing of S430. Therefore, the cumulative time T(n) of temperature section (n) calculated by equation (8) is equal to the value obtained by subtracting the integrated cumulative time ST before being updated in the processing of S430 from the stop time Tsp.

[0080] When the process of S470 is completed or when the determination in S460 is affirmative, the CPU 310 executes a process of converting each of the accumulated times T(n) for each temperature range calculated in this process into the counter value Cn (S480). In the process of S480, the CPU 310 converts the accumulated time T(n) into the counter value Cn by dividing the accumulated time T(n) by the sampling period of the cooling water temperature THW.

[0081] Then, when the process of S480 ends, the CPU 310 ends this process, that is, ends the process of S210 shown in FIG. 8 ends, the CPU 310 then executes a process of updating each counter value Cn stored in the memory 320 in association with the vehicle ID (S220 in FIG. 8). In the process of S220, the CPU 310 adds the counter value Cn for each temperature category during the operation shutdown calculated in the process of S210 to each counter value Cn stored in the memory 320, thereby updating each counter value Cn stored in the memory 320. Then, the CPU 310 ends the series of processes shown in FIG.

[0082] <Action and effect> The operation and effects of this embodiment will be described. (1) By executing the heat reception history estimation process, the counter value Cn indicating the heat reception history of the coolant is estimated even when the operation of the control device 100 is stopped. Then, in the series of processes shown in Fig. 6, the deterioration degree R of the coolant is calculated based on data including the counter value Cn during the operation stoppage. In this way, the deterioration of the coolant is estimated taking into account the heat reception history of the coolant during the operation stoppage of the control device 100, thereby improving the accuracy of estimating the deterioration of the coolant.

[0083] (2) The cumulative time T(n) for calculating the counter value Cn is calculated based on the function formula (5) above, which uses the stop-time information as an input variable. In the process of S340 shown in FIG. 9, the constant A included in the function formula (5) is calculated based on the function formula (7) above, which uses the stop-time information, the water temperature at the start of operation THWs, and the stop time Tsp as input variables. In this way, the constant A included in the function formula is calculated based on the actual coolant temperature and outside air temperature. Therefore, the influence of individual differences in the internal combustion engine 15 on the estimation of the cumulative time T(n) can be reduced.

[0084] (3) As described above, when the stop time Tsp of the internal combustion engine 15 is excessively short or excessively long, the deviation between the estimated value and the actual value of the coolant temperature may become large. When the deviation between the estimated value and the actual value of the coolant temperature becomes large, the deviation between the estimated counter value Cn during the operation stop and the counter value Cn corresponding to the actual change in the coolant temperature may become large. In a situation where such a deviation occurs, if the constant A is calculated by the process of S340 shown in FIG. 9, the accuracy of the constant A may decrease. In this regard, in the present embodiment, it is determined whether the stop time Tsp is within a predetermined range (process of S310). Then, the constant A is calculated when the stop time Tsp is within the predetermined range. Therefore, the calculation accuracy of the constant A is improved compared to when the constant A is calculated without imposing any restrictions on the stop time Tsp.

[0085] (4) In order to acquire the cumulative time for each temperature of the cooling water temperature THW (corresponding to the counter value Cn in this embodiment), multiple temperature categories are set. Therefore, compared to acquiring the cumulative time for each temperature without setting such temperature categories, the memory capacity required to store such cumulative time can be reduced.

[0086] (5) The deterioration function formula (1) is used, in which the deterioration level R increases as the coolant temperature increases, and the coolant temperatures corresponding to the respective deterioration levels R obtained by equally dividing the deterioration level reference value Rhi are set as the boundary values ​​of the above-mentioned temperature ranges. Therefore, the temperature ranges are subdivided as the temperature increases, where the coolant deterioration is more likely to progress. This improves the accuracy of estimating the deterioration level R of the coolant.

[0087] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0088] The number of temperature divisions for the coolant temperature THW and the range of each temperature division may be changed as appropriate. The counter value Cn may be calculated for each sampled cooling water temperature THW without providing temperature divisions.

[0089] The timing of transmitting the operating temperature information described above may be changed as appropriate. The process of S160 shown in FIG. 6 may be omitted. Although the boundary values ​​of the temperature ranges are set based on the degradation function formula described above, the boundary values ​​may be set in other ways. For example, the boundary values ​​of the temperature ranges may be set so that the temperature ranges of the temperature ranges for high water temperatures and temperature ranges for which the counter value Cn tends to increase are narrower than the temperature ranges of the other temperature ranges.

[0090] Instead of the counter value Cn, the cumulative time may be calculated. The conversion process of S120 shown in Fig. 6 is executed by the control device 100. Then, as the operating temperature information to be transmitted to the data analysis device 300, the converted counter value CCn may be transmitted instead of the counter value Cn.

[0091] The processes of S210 and S220 shown in FIG. All of the above-described processes may be executed by the control device 100. The cooling water temperature THW acquired while the control device 100 is operating is transmitted in real time to the data analysis device 300. The counter value Cn may then be updated by the data analysis device 300.

[0092] The execution device is equipped with a CPU and memory, and is not limited to one that executes software processing. For example, it may also be equipped with a dedicated hardware circuit (e.g., ASIC) that processes at least part of the software processing executed in each of the above embodiments. That is, the execution device may have any of the following configurations (a) to (c): (a) It comprises a processing device that executes all of the above processing in accordance with a program, and a program storage device such as memory that stores the program. (b) It comprises a processing device and program storage device that executes part of the above processing in accordance with a program, and a dedicated hardware circuit that executes the remaining processing. (c) It comprises a dedicated hardware circuit that executes all of the above processing. Here, there may be multiple software processing circuits and dedicated hardware circuits that include a processing device and program storage device. That is, the above processing may be executed by a processing circuit that includes at least one of one or more software processing circuits and one or more dedicated hardware circuits. [Explanation of symbols]

[0093] 10…Cooling device 12...Radiator 15...Internal combustion engine 15W...Water jacket 16...1st aisle 17…Second aisle 18...Water pump 20... Branching passage 25...Thermostat 34...Water temperature sensor 35...Outside air temperature sensor 100...Control device 110...Central processing unit (CPU) 120...Memory 130...Communication device 200…Network 300...Data analysis equipment 310...CPU 320...Memory 330...Communication device 500...vehicle 600...vehicle

Claims

[Claim 1] A system for estimating deterioration of coolant for an internal combustion engine, an execution unit; The execution device an acquisition process for acquiring data relating to a heat reception history of the cooling water during operation of the execution device; a heat reception history estimation process for estimating a heat reception history of the cooling water while the execution device is stopped based on stop time information including the temperature of the cooling water and an outside air temperature at the time the execution device is stopped when the engine is stopped; and executing an estimation process for estimating the deterioration based on data relating to the heat reception history of the cooling water while the execution device is in operation and the heat reception history of the cooling water while the execution device is not in operation. Cooling water deterioration estimation system.

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