JP2023167299A - Deterioration estimation system for cooling water - Google Patents

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

The present invention relates to a cooling water deterioration estimation system.

Cooling water for an internal combustion engine deteriorates depending on its heat reception history. Therefore, for example, the device described in Patent Document 1 estimates the deterioration of the cooling water depending on the temperature state of the cooling water.

International Publication No. 2012/107990

Incidentally, even after the operation of the internal combustion engine is stopped, the cooling water remains at a high temperature for a while. Therefore, deterioration of the cooling water progresses even while the internal combustion engine is stopped. Here, when the operation of the control device is stopped due to engine stoppage, the temperature of the cooling water while the engine is stopped cannot be obtained, so there is a possibility that the accuracy of estimation regarding the deterioration of the cooling water may be reduced.

A cooling water deterioration estimation system that solves the above problems is a system that estimates the deterioration of a cooling water for an internal combustion engine. This deterioration estimation system includes an execution device. This execution device includes an acquisition process for acquiring data regarding the heat reception history of the cooling water, an estimation process for estimating the deterioration based on the data, and a process at the time when the execution device stops operating when the engine is stopped. A heat reception history estimating process is executed to estimate a heat reception history of the cooling water while the execution device is not operating, based on stoppage information including the temperature of the cooling water and the outside air temperature.

According to this configuration, by executing the heat reception history estimation process, the heat reception history of the cooling water is estimated even if the execution device is not operating. Then, the deterioration of the cooling water is estimated based on data including the heat reception history of the cooling water while the operation is stopped. In this way, the deterioration is estimated taking into account the heat reception history of the cooling water while the execution device is not operating, so the accuracy of estimating the deterioration of the cooling water is improved.

In the deterioration estimation system, the heat reception history may be a cumulative time for each cooling water temperature. In this case, as the heat reception history estimating process, a process of calculating the cumulative time based on a functional formula using the stop time information as an input variable may be executed.

In the deterioration estimation system, the functional expression includes a constant, and the execution device inputs the stoppage information, the temperature of the cooling water at the time of starting the engine, and the stoppage time of the engine from when the engine is stopped until the engine is started as input variables. A calculation process may be performed to calculate the constant based on a functional formula.

According to this configuration, constants included in the functional expression are calculated based on the actual cooling water temperature and outside air temperature. Therefore, the influence of individual differences among internal combustion engines on the estimation of the heat reception history can be suppressed.

In the deterioration estimation system, the execution device may calculate the constant when the stop time is within a predetermined range.
If the engine stop time is excessively short or excessively long, the discrepancy between the estimated value and the actual value of the heat reception history of the cooling water may become large. If the constant is calculated in a state where the deviation between the estimated value and the actual value is large, the accuracy of the constant may decrease. In this regard, with the same configuration, the constant is calculated when the engine stop time is within a predetermined range, so compared to the case where the constant is calculated without setting a limit on the engine stop time, The accuracy of constant calculation will improve.

In the deterioration estimation system, a plurality of temperature classes are set, and the cumulative time for each temperature of the cooling water may be the cumulative time for each temperature class.
According to this configuration, a plurality of temperature categories are set in order to obtain the cumulative time for each cooling water temperature. Therefore, compared to the case where such temperature divisions are not set, it is possible to reduce the memory capacity required to store the cumulative time.

FIG. 1 is a schematic diagram showing the configuration of a deterioration estimation system in an embodiment. It is a flowchart which shows the procedure of the process performed by the control device of the same embodiment. It is a graph which shows the temperature classification and counter value of the same embodiment. It is a graph showing the relationship between temperature classification and cooling water temperature in the same embodiment. It is a flowchart which shows the procedure of the process performed by the control device of the same embodiment. It is a flowchart which shows the procedure of the process performed by the data analysis apparatus of the same embodiment. It is a graph which shows the temperature classification and conversion counter value of the same embodiment. It is a flowchart which shows the procedure of the process performed by the data analysis apparatus of the same embodiment. It is a flowchart which shows the procedure of the process performed by the data analysis apparatus of the same embodiment. It is a flowchart which shows the procedure of the process performed by the data analysis apparatus of the same embodiment.

<System configuration>
An embodiment in which a cooling water deterioration estimation system is applied to an internal combustion engine mounted on a vehicle will be described below with reference to FIGS. 1 to 10.

As shown in FIG. 1, the vehicle 500 includes an internal combustion engine 15, a cooling device 10, and the like. The cooling device 10 is a device that cools the internal combustion engine 15 with cooling water. This cooling water contains anti-rust agents and the like.

The cooling device 10 includes a radiator 12 that is a heat exchanger. A water jacket 15W is formed inside the cylinder block and cylinder head of the internal combustion engine 15. The cooling water outlet of the water jacket 15W and the cooling water inlet of the radiator 12 are connected through a first passage 16. Further, the cooling water inlet of the water jacket 15W and the cooling water outlet of the radiator 12 are connected through a second passage 17. A water pump 18 is provided on the path of the second passage 17.

The cooling device 10 includes a branch passage 20 that is a passage branched from the first passage 16 and 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 inside changes depending on the temperature of the cooling water. The reflux flows through the branch passage 20 without any problems. On the other hand, when the temperature of the cooling water is high, the cooling water flowing out of the water jacket 15W flows back through the radiator 12 instead of through the branch passage 20.

The control device 100 performs various controls such as the amount of intake air and the amount of fuel injected into the internal combustion engine 15. The control device 100 includes a central processing unit (hereinafter referred to as CPU) 110, a memory 120 in which control programs and data are stored, a communication device 130, and the like. The control device 100 executes various controls by having the CPU 110 execute programs stored in the memory 120. Further, the control device 100 can communicate with the data analysis device 300 via the external network 200 using the communication device 130. Note that in this embodiment, the control device 100 including the CPU 110 and the memory 120 constitutes a first execution device.

The control device 100 refers to various detected values obtained from sensors and the like when performing various controls. For example, the control device 100 refers to the cooling water temperature THW, which is the temperature of the cooling water detected by the water temperature sensor 34, and the outside temperature THout, which is detected by the outside temperature sensor 35.

The data analysis device 300 analyzes data transmitted from a plurality of vehicles 500, 600, and the like. The data analysis device 300 includes a CPU 310, a memory 320, a communication device 330, and the like, which can communicate with each other via the network 200. Note that in this embodiment, the data analysis device 300 including the CPU 310 and the memory 320 constitutes a second execution device.

<Calculating the degree of deterioration of cooling water>
The cooling water of the internal combustion engine 15 deteriorates due to oxidation depending on the heat reception history expressed by the heat reception temperature and heat reception time. As deterioration progresses in this way, the effectiveness of additives such as rust preventives decreases. Therefore, in this embodiment, the deterioration of the cooling water is estimated by calculating the degree of deterioration R of the cooling water.

Note that in this embodiment, the larger the value of the degree of deterioration R, the more advanced the deterioration is. Further, as physical quantities for determining the degree of deterioration in tests and the like, hydrogen ion concentration (so-called pH) and electrical conductivity of cooling water are used. In addition, for verification with actual vehicles, for example, an analysis of the remaining components of the cooling water and an investigation of the state of rust in the recovered cooling system will be conducted.

Hereinafter, calculation of the degree of deterioration R will be explained.
FIG. 2 shows a procedure of processing executed by the control device 100. The processing shown in FIG. 2 is realized by the CPU 110 executing a program stored in the memory 120. Note that the process shown in FIG. 2 is executed when the engine is started. Further, in the following, step numbers will be expressed by numbers prefixed with "S".

When this process is started, the CPU 110 transmits the vehicle ID, which is the identification information of the vehicle 500, the starting information, and the stopping 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 operating at the current engine start, and an operation start time Ts, which is the time at which the operation starts.

Further, the stoppage information includes, for example, a water temperature THWe at the time of stoppage, which is the cooling water temperature THW at the time when the operation of the control device 100 was stopped at the time of the engine stop immediately before, and a stoppage time Te, which is the time at the time when the operation was stopped. Further, the stoppage information includes, for example, the outside temperature THout when the operation is stopped, which is the outside temperature THout at the time when the operation is stopped.

Next, the CPU 110 starts the process of acquiring operating temperature information (S12), and ends this process. The operating temperature information is the cumulative time for each cooling water 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 cooling water temperature THW is a value indicating the heat reception history of the cooling water.

FIG. 3 shows an example of the cumulative time for each cooling water temperature THW acquired in the acquisition process.
In this embodiment, a plurality of temperature categories are set, and the cumulative time for each temperature of the cooling water temperature THW is represented by a counter value Cn indicating the cumulative time for each temperature class. Note that the counter value Cn is a value calculated for each temperature category, which will be described later, and the number "n" indicates the corresponding temperature category. Incidentally, by multiplying the counter value Cn by the sampling period of the cooling water temperature THW, it is also possible to convert the counter value Cn into the cumulative time for each temperature category.

In this embodiment, ten temperature categories are set. These temperature divisions are, in descending order of temperature, first temperature division TR1, second temperature division TR2, third temperature division TR3, fourth temperature division TR4, fifth temperature division TR5, sixth temperature division TR6, and third temperature division TR3. There are 7 temperature divisions TR7, 8th temperature division TR8, 9th temperature division TR9, and 10th temperature division TR10.

The first temperature classification TR1 is a temperature range below the predetermined first water temperature THW1. The counter value Cn of this first temperature division TR1 is referred to as a first counter value C1.
The second temperature classification TR2 is a temperature range from the first water temperature THW1 to less than the second water temperature THW2. The counter value Cn of this second temperature division TR2 is referred to as a second counter value C2.

The third temperature classification TR3 is a temperature range from the second water temperature THW2 to less than the third water temperature THW3. The counter value Cn of this third temperature division TR3 is referred to as a third counter value C3.
The fourth temperature classification TR4 is a temperature range from the third water temperature THW3 to less than the fourth water temperature THW4. The counter value Cn of this fourth temperature division TR4 is referred to as a fourth counter value C4. This fourth temperature section TR4 is a section to which a reference temperature THWb, which will be described later, belongs.

The fifth temperature division TR5 is a temperature range from the fourth water temperature THW4 to less than the fifth water temperature THW5. The counter value Cn of this fifth temperature division TR5 is referred to as a fifth counter value C5.
The sixth temperature division TR6 is a temperature range from the fifth water temperature THW5 to less than the sixth water temperature THW6. The counter value Cn of this sixth temperature division TR6 is referred to as a sixth counter value C6.

The seventh temperature division TR7 is a temperature range from the sixth water temperature THW6 to less than the seventh water temperature THW7. The counter value Cn of this seventh temperature division TR7 is referred to as a seventh counter value C7.
The eighth temperature division TR8 is a temperature range from the seventh water temperature THW7 to less than the eighth water temperature THW8. The counter value Cn of this eighth temperature division TR8 is referred to as an eighth counter value C8.

The ninth temperature division TR9 is a temperature range from the eighth water temperature THW8 to less than the ninth water temperature THW9. The counter value Cn of this ninth temperature division TR9 is referred to as a ninth counter value C9.
The tenth temperature division TR10 is a temperature range equal to or higher than the ninth water temperature THW9. The counter value Cn of this tenth temperature division TR10 is referred to as a tenth counter value C10.

FIG. 4 shows the relationship between temperature categories and cooling water temperature.
Cooling water for internal combustion engines deteriorates when ethylene glycol, one of its components, is decomposed by heat and converted into formic acid or glycolic acid, becoming acidic. Further, the higher the cooling water temperature, the more likely the cooling water deteriorates. Therefore, there is a correlation between the cooling water temperature THW and the degree of deterioration R, and when the functional expression indicating the relationship between the cooling water temperature THW and the degree of deterioration R is taken as a deterioration function expression, this deterioration function expression is It is possible to use a functional expression in which the degree of deterioration R increases as the degree of deterioration increases.

Here, it is known that the degree of deterioration of the cooling water follows the 10°C double law, which is Arrhenius's law. Therefore, for example, when the cooling water temperature THW is 90° C., the degree of deterioration R is set to “100” which is a dimensionless value. It is also possible to use the function f(THW) of the following equation (1), which uses the cooling water temperature THW as an input variable, as a deterioration function.

R=f(THW)=100×2＾{(THW-90)/10}...(1)
In the present embodiment, when the number of temperature divisions to be set is n, and the deterioration degree R at a predetermined cooling water temperature is the deterioration degree reference value Rhi, the deterioration degree reference value Rhi is set to "n-1". Divide equally by value. Then, the cooling water temperature corresponding to each equally divided degree of deterioration R is calculated from the above deterioration function formula, and each calculated cooling water temperature is set as a boundary value for each temperature division.

As an example, in this embodiment, ten temperature categories are set. Therefore, "10" is substituted for the above "n". Further, as the predetermined cooling water temperature, the maximum allowable cooling water temperature THWhi expected during normal use is set. 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.

Next, the deterioration level reference value Rhi is equally divided by "9" which is the value of "n-1". These equally divided deterioration degrees are arranged in order of decreasing value: first deterioration degree R1, second deterioration degree R2, third deterioration degree R3, fourth deterioration degree R4, fifth deterioration degree R5, sixth deterioration degree R6, A seventh degree of deterioration R7, an eighth degree of deterioration R8, and a ninth degree of deterioration R9 are assumed. Note that the ninth deterioration degree R9 is the same as the deterioration degree reference value Rhi.

Then, the cooling water temperature corresponding to each equally divided degree of deterioration R is calculated from the above deterioration function formula. That is, with "n=1 to 9", the cooling water temperature THW corresponding to the n-th degree of deterioration Rn is calculated from the above-mentioned deterioration function formula, and the calculated value is set as the above-mentioned n-th water temperature THWn.

More specifically, the cooling water temperature THW corresponding to the first degree of deterioration R1 is calculated from the above deterioration function formula, and the calculated value is set as the first water temperature THW1.
Further, the cooling water temperature THW corresponding to the second degree of deterioration R2 is calculated from the above deterioration function formula, and the calculated value is set as the second water temperature THW2.

Further, the cooling water temperature THW corresponding to the third degree of deterioration R3 is calculated from the above deterioration function formula, and the calculated value is set as the third water temperature THW3.
Further, the cooling water temperature THW corresponding to the fourth degree of deterioration R4 is calculated from the above deterioration function formula, and the calculated value is set as the fourth water temperature THW4.

Further, the cooling water temperature THW corresponding to the fifth degree of deterioration R5 is calculated from the above deterioration function formula, and the calculated value is set as the fifth water temperature THW5.
Further, the cooling water temperature THW corresponding to the sixth degree of deterioration R6 is calculated from the above deterioration function formula, and the calculated value is set as the sixth water temperature THW6.

Further, the cooling water temperature THW corresponding to the seventh degree of deterioration R7 is calculated from the above deterioration function formula, and the calculated value is set as the seventh water temperature THW7.
Further, the cooling water temperature THW corresponding to the eighth degree of deterioration R8 is calculated from the above deterioration function formula, and the calculated value is set as the eighth water temperature THW8.

The maximum allowable 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 separates the first temperature section TR1 to the tenth temperature section TR10, respectively. By adopting such a method of setting temperature divisions, as shown in FIG. 4, in this embodiment, the temperature divisions are divided into higher temperature regions where cooling water tends to deteriorate more easily.

When the process of S12 described above is started, the CPU 110 acquires the cooling water temperature THW at each predetermined sampling period. Then, while the control device 100 is in operation, a process of increasing the counter value Cn of the temperature category to which the obtained cooling water temperature THW belongs by a predetermined value α (for example, 1, etc.) is repeatedly executed. As a result, the counter value Cn corresponding to the cumulative time of the cooling water temperature THW for each temperature is updated for each temperature category. Then, each updated counter value Cn is stored in the memory 120.

FIG. 5 shows a procedure of processing that the control device 100 executes at every predetermined period.
When starting this process, the CPU 110 determines whether there is a request to send temperature information during operation (S20). For example, if a predetermined period of time has passed since the last time the operating temperature information was transmitted, the CPU 110 determines that there is a request to transmit the operating temperature information. Note that examples of the predetermined period include the operating time of the control device 100 and the mileage of the vehicle 500.

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

<Processing executed by data analysis device 300>
FIG. 6 shows the procedure of the process executed by the CPU 310 when the data analysis device 300 receives the data transmitted in the process of S22 shown in FIG.

At S100, upon receiving the vehicle ID and the counter value Cn, which is operating temperature information, transmitted from the control device 100, the CPU 310 executes the process at S110. The process of S110 is a process of updating each counter value Cn for each temperature category stored in the memory 320 in association with the vehicle ID, and saving the updated counter value Cn in the memory 320. The counter value Cn is updated by adding the received counter value Cn to each counter value Cn for each temperature category stored in the memory 320. Through such updating, each counter value Cn for each temperature category stored in the memory 320 becomes an integrated value of each counter value Cn for each temperature category received up to that point.

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 conversion value obtained by converting each of the counter values Cn for each temperature category into a counter value Cn corresponding to the cumulative time at a predetermined reference temperature THWb (for example, about 90° C.). That is, the converted counter value CCn is a value obtained by converting the counter value Cn for each temperature category into a counter value when it is assumed that the cooling water temperature THW is the reference temperature THWb. In other words, when the degree of deterioration corresponding to the counter value Cn for each temperature category is defined as the degree of deterioration Rn, the value of the counter value Cn required to reach the degree of deterioration Rn at the reference temperature THWb is the converted counter value CCn. Note that the number "n" in the converted counter value CCn is the same as the number "n" in the original counter value Cn, and indicates the corresponding temperature category.

This conversion process is performed as follows.
As shown in FIG. 7, first, for each of the first temperature section TR1 to the tenth temperature section TR10, a first representative temperature P1, a second representative temperature P2, a third representative temperature P3, which are the representative temperatures of the temperature section, A fourth representative temperature P4, a fifth representative temperature P5, a sixth representative temperature P6, a seventh representative temperature P7, an eighth representative temperature P8, a ninth representative temperature P9, and a tenth representative temperature P10 are each determined in advance. In addition, below, each of these representative temperatures will be collectively referred to as representative temperature Pn. Further, a number indicating the temperature category is substituted for "n".

The second representative temperature P2 to the ninth representative temperature P9 are obtained from the following equation (2). Note that any value from 2 to 9 is substituted for "n" in equation (2). Further, the coefficient K is a value greater than "0" and smaller than "1", and an optimal value for reducing the error in the degree of deterioration R is set in advance.

Pn=THW(n-1)+(THWn-THW(n-1)×coefficient K)...(2)
As an example, when the coefficient K is "0.4", the second representative temperature P2, which is the representative temperature of the second temperature classification TR2, is "first water temperature THW1 + (second water temperature THW2 - first water temperature THW1) x 0. 4" is the value found.

Furthermore, the first representative temperature P1 and the tenth representative temperature P10 are preset at optimal temperatures for reducing the error in the degree of deterioration R.
The lower the cooling water temperature THW is, the more difficult it is for the cooling water to deteriorate. Therefore, as shown in FIG. 7, in the temperature category where the representative temperature Pn is lower than the reference temperature THWb, the converted counter value CCn (shown by the solid line) is lower than the counter value Cn before conversion (shown by the two-dot chain line). The counter value Cn is converted so that the value becomes smaller. Further, the higher the cooling water temperature THW, the more easily the cooling water deteriorates. Therefore, as shown in FIG. 7, in a temperature category where the representative temperature Pn is higher than the reference temperature THWb, the converted counter value CCn (shown as a solid line) is lower than the pre-conversion counter value Cn (shown as a two-dot chain line). The counter value Cn is converted so that the value becomes larger.

To calculate the converted counter value CCn for each temperature category, input the representative temperature Pn determined for each temperature category and the counter value Cn of the temperature category to which the representative temperature Pn belongs, and output the converted counter value CCn. This is done using a functional formula.

Next, the CPU 310 calculates the sum S of all the converted counter values CCn calculated for each temperature category (S130).
Next, the CPU 310 executes a calculation process to calculate the degree of deterioration R based on the calculated sum S (S140). Here, a relational expression between the sum S and the degree of deterioration R is determined in advance, and the CPU 310 calculates the degree of deterioration R based on such a relational expression. Note that the degree of deterioration R is calculated such that the larger the value of the sum S, the greater the value of the degree of deterioration R. After calculating the degree of deterioration R in this way, the CPU 310 stores the calculated degree of deterioration R in the memory 320 (S150).

Next, the CPU 310 executes a process of calculating the expected cooling water replacement time based on the amount of change in the degree of deterioration R (S160). In S160, the CPU 310 performs the following processing, for example. That is, the CPU 310 calculates the difference between the previously calculated degree of deterioration R and the currently calculated degree of deterioration R. Further, the CPU 310 calculates an elapsed period (e.g., elapsed time or travel distance) from calculating the previous degree of deterioration R to calculating the current degree of deterioration R. Then, based on the calculated difference and the elapsed period, the time and travel distance until the degree of deterioration R reaches the allowable limit value are calculated. Then, the calculated time and mileage are set as the expected replacement time. When the process of S160 is completed, the CPU 310 ends the current main process.

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

Upon receiving the vehicle ID, starting information, and stopping information transmitted from control device 100 in S200, CPU 310 then executes the process in S210. The process of S210 is a heat reception history estimation process for estimating the heat reception history of the cooling water while the operation of the control device 100 is stopped based on the above-mentioned stop information, that is, each counter value Cn for each temperature category while the operation is stopped is estimated based on the stop information. This is a process that is calculated based on .

In the process of S210, each counter value Cn during the operation stop is calculated as follows.
First, after the engine is stopped, according to the law of heat radiation, initially a large amount of heat is radiated from the cooling water temperature, causing the temperature to drop significantly. After that, the temperature decreases at a slower rate and finally converges to the ambient temperature, that is, the outside temperature. Therefore, the cooling water temperature THW(t) at the elapsed time t after the engine is stopped is determined by the function formula shown in the following equation (3) based on the water temperature THWe at the time of stoppage and the outside air temperature THoute at the time of stoppage, which are included in the information at the time of stoppage. The present inventor has confirmed that it can be calculated from

Note that although a predetermined value is set as an initial value for the constant A in equation (3), the value is updated by an update process described later.

Further, the elapsed time tx when the cooling water temperature THW reaches a certain temperature THWx can be determined from the functional expression shown in the following equation (4), which is a modification of the equation (3). Note that "log" described in each formula below is a natural logarithm with "e" as the base.

Therefore, the cumulative time T(n) of the cooling water in any temperature range can be determined from the functional expression shown in the following equation (5). Note that "n" is a value indicating a temperature category, and can take a value of "1 to 10".

For example, the cumulative time T9 in the ninth temperature category TR9 can be calculated based on the following equation (6) in which "9" is substituted for "n" in equation (5). That is, this cumulative time T9 can be calculated based on the ninth water temperature THW9, the eighth water temperature THW8, and the outside air temperature THoute at the time of operation stop.

Note that when calculating the cumulative time T10 in the tenth temperature category TR10, the value of the water temperature THWe at the time of operation stop is substituted for the value of "THW(n)" in equation (5).

In addition, when calculating the cumulative time T1 in the first temperature category TR1, the value of "THW(n-1)" in equation (5) is changed from the first water temperature THW1 to a predetermined value (for example, 10°C to 20°C). Substitute the value obtained by subtracting the value (about °C).

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

Based on each of these functional expressions, the CPU 310 calculates each counter value Cn for each temperature category during which the operation is stopped.

9 and 10 show the processing procedure for calculating the counter value Cn while the operation is stopped.
When this process is started, the CPU 310 subtracts the operation stop time Te included in the stop information from the operation start time Ts included in the start information to determine the stop time, which is the time during which the control device 100 has stopped operating. Calculate Tsp.

Next, the CPU 310 determines whether the stop time Tsp is within a range of not less than a threshold value A and not more than a threshold value B (S310). The determination process at S310 is executed for the following reason. That is, if the stop time Tsp is too short or too long, there is a risk that the difference between the estimated value and the actual value of the cooling water temperature will become large. When the discrepancy between the estimated value and the actual value of the cooling water temperature becomes large, there is a possibility that the discrepancy between the estimated value of the counter value Cn during operation stoppage and the counter value Cn corresponding to the actual change in the cooling water temperature becomes large. . If the constant A is calculated in the process of S340 described below under a situation where such a deviation occurs, the accuracy of the constant A may decrease. Therefore, in order to calculate the constant A when the stop time Tsp is a value within a predetermined range and is a time suitable for calculating the constant A, a process for determining the stop time Tsp is executed in the process of S310. . Therefore, the upper limit value and the lower limit value of the stop time Tsp with which the constant A can be calculated with high accuracy are set in advance for the threshold value A and the threshold value B, respectively.

In the process of S310, if it is determined that the stop time Tsp is a value within the range of not less than the threshold value A and not more than the threshold value B (S310: YES), the CPU 310 determines whether the water temperature THWs at the start of operation is greater than the outside temperature THoute at the time the operation is stopped. It is determined whether the temperature is also high (S320). If it is determined that the water temperature THWs at the start of operation is higher than the outside air temperature THoute at the time of stoppage of operation (S320: YES), the CPU 310 executes the calculation process of S340. The calculation process of S3400 is a process of calculating the constant A by substituting the stop time Tsp, the water temperature at the start of operation THWs, the water temperature at the time of stoppage of operation THWe, and the outside temperature at the time of stoppage of operation THoute to the above equation (7).

On the other hand, if it is determined in the process of S320 that the water temperature THWs at the start of operation is equal to or lower than the outside air temperature THoute at the time of stopping the operation (S320: NO), the CPU 310 executes a process for correcting the outside air temperature THoute at the time of stopping the operation. (S330). In the process of S330, the CPU 310 executes a process of reducing the value of the outside temperature THoute at the time of operation stoppage by subtracting a predetermined value from the acquired outside temperature THoute at the time of operation stoppage. This process is a measure to avoid log calculation becoming impossible if the value of "THWs-THoute" in the function formula of equation (7) becomes a negative value when calculating the constant A in the process of S340. It is.

After performing the process of S330 in this manner, the CPU 310 calculates the constant A in the process of S340.
Next, the CPU 310 executes processing to update constant A (S350). In the process of S350, the CPU 310 calculates the arithmetic average of a plurality of constants A including the constant A calculated in the current process and a plurality of constants A calculated most recently. Then, by substituting the calculated arithmetic average value into the constant A, the constant A is updated.

When the process of S350 is finished, or when a negative determination is made in the process of S310, the CPU 310 executes the process from S360 shown in FIG. 10.
As shown in FIG. 10, as the process of S360, the CPU 310 resets the cumulative time T(n) of each temperature category (n) to "0". Note that "n" is a value representing a temperature category, and can take a value of "1 to 10".

Next, the CPU 310 determines the temperature category (n) to which the water temperature THWe at the time of suspension of operation, acquired through the process of S10 shown in FIG. 2, belongs (S410).
Next, the CPU 310 calculates the cumulative time T(n) in the temperature category (n) determined in the process of S410 based on the above equation (5) (S420).

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

Next, the CPU 310 determines whether the updated integrated cumulative time ST is shorter than the stop time Tsp (S440). If it is determined that the updated integrated cumulative time ST is shorter than the stop time Tsp (S440: YES), the value of "n" is changed by one in order to change the temperature category for calculating the cumulative time T(n). A process of reducing the size is executed (S450). The process of S450 is a preprocessing for changing the temperature category for calculating the cumulative time T(n) to a temperature category one step lower in temperature.

Next, the CPU 310 determines whether the value of "n" updated in the process of S450 is "0" (S460). Then, when determining that the value of "n" is not "0" (S460: NO), the CPU 310 repeatedly executes the processes from S420 onward to calculate the cumulative time T(n) of each temperature category (n). Calculate each.

If it is determined in the process of S440 that the integrated cumulative time ST is equal to or greater than the stop time Tsp (S440: NO), the CPU 310 updates "n" updated in the process of S450 based on the following equation (8). The cumulative time T(n) of the temperature category (n) corresponding to is calculated.

T(n) = Stop time Tsp-ST-T(n)...(8)
Note that "ST" written on the right side of equation (8) is the integrated cumulative time ST after being updated in the process of S430. Furthermore, "T(n)" written on the right side of equation (8) is the cumulative time T(n) calculated in the process 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 process of S430. Therefore, the cumulative time T(n) of the temperature category (n) calculated by equation (8) is equal to the value obtained by subtracting the cumulative cumulative time ST before being updated in the process of S430 from the stop time Tsp.

When the process of S470 is finished, or when an affirmative determination is made in the process of S460, the CPU 310 sets each of the cumulative times T(n) of each temperature category calculated in this process to the counter value Cn. The conversion process is executed (S480). As the process of S480, the CPU 310 converts the cumulative time T(n) into a counter value Cn by dividing the cumulative time T(n) by the sampling period of the cooling water temperature THW.

After completing the process of S480, the CPU 310 ends this process. That is, the process of S210 shown in FIG. 8 is ended.
After completing the process of S210 shown in FIG. 8, the CPU 310 next executes a process of updating each counter value Cn stored in the memory 320 in association with the vehicle ID (S220 of FIG. 8). As the process of S220, the CPU 310 adds the counter value Cn of each temperature category during operation stop calculated in the process of S210 to each counter value Cn stored in the memory 320, and saves the result in the memory 320. Each counter value Cn that has been updated is updated. Then, the CPU 310 ends the series of processing shown in FIG.

<Action and effect>
The operation and effects of this embodiment will be explained.
(1) By executing the heat reception history estimation process, the counter value Cn indicating the heat reception history of the cooling water is estimated even if the operation of the control device 100 is stopped. In the series of processes shown in FIG. 6, the degree of deterioration R of the cooling water is calculated based on data including the counter value Cn during the stoppage of operation. In this way, the deterioration of the cooling water is estimated taking into consideration the heat reception history of the cooling water while the operation of the control device 100 is stopped, so that the accuracy of estimating the deterioration of the cooling water is improved.

(2) The cumulative time T(n) for calculating the counter value Cn is calculated based on the function equation (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 equation (5) is changed to the above equation (7) using the stop time information, the water temperature at the start of operation THWs, and the stop time Tsp as input variables. It is calculated based on a functional formula. In this way, the constant A included in the functional formula is calculated based on the actual cooling water temperature and outside air temperature. Therefore, the influence of individual differences among the internal combustion engines 15 on the estimation of the cumulative time T(n) can be suppressed.

(3) As described above, if the stop time Tsp of the internal combustion engine 15 is too short or too long, there is a risk that the difference between the estimated value and the actual value of the cooling water temperature will become large. When the discrepancy between the estimated value and the actual value of the cooling water temperature becomes large, there is a possibility that the discrepancy between the estimated value of the counter value Cn during operation stoppage and the counter value Cn corresponding to the actual change in the cooling water temperature becomes large. . If the constant A is calculated in the process of S340 shown in FIG. 9 under a situation where such a deviation occurs, 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 (processing of S310). Then, the constant A is calculated when the stop time Tsp is within a predetermined range. Therefore, the accuracy of calculating the constant A is improved compared to the case where the constant A is calculated without setting a limit on the stop time Tsp.

(4) A plurality of temperature categories are set in order to obtain the cumulative time for each cooling water temperature THW (corresponding to the counter value Cn in this embodiment). Therefore, compared to the case where the cumulative time of each temperature is acquired without setting such temperature classifications, the memory capacity required to store such cumulative time can be reduced.

(5) In addition to using the deterioration function formula of the above formula (1) in which the degree of deterioration R increases as the temperature of the cooling water becomes higher, each degree of deterioration R obtained by equally dividing the above deterioration degree reference value Rhi is used. The temperature of the corresponding cooling water is set to the boundary value of each temperature category described above. Therefore, the higher the temperature range where cooling water tends to deteriorate, the more detailed the temperature classification becomes. Therefore, the accuracy of estimating the degree of deterioration R of the cooling water is improved.

<Example of change>
The above embodiment can be modified and implemented as follows. The above embodiment and the following modification examples can be implemented in combination with each other within a technically consistent range.

- The number of temperature divisions of the cooling water temperature THW and the range of each temperature division may be changed as appropriate.
- The counter value Cn may be obtained for each sampled cooling water temperature THW without providing temperature divisions.

- The transmission timing of 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 categories are set based on the above-mentioned deterioration function formula, the boundary values may be set in other ways. For example, the boundary values of the temperature categories may be set so that the temperature range of the temperature category with high water temperature or the temperature category where the value of the counter value Cn tends to be large is narrower than the temperature range of other temperature categories. .

- The above cumulative time may be calculated instead of the counter value Cn.
- 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, a converted counter value CCn may be transmitted instead of the counter value Cn.

- The processing of S210 and S220 shown in FIG. 8 may be executed by the control device 100.
- All the processes described above may be executed by the control device 100.
- Sends the cooling water temperature THW acquired during operation of the control device 100 to the data analysis device 300 in real time. Then, the counter value Cn may be updated by the data analysis device 300.

- The execution device is not limited to one that includes a CPU and a memory and executes software processing. For example, a dedicated hardware circuit (eg, ASIC, etc.) may be provided to process 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 includes a processing device that executes all of the above processing according to a program, and a program storage device such as a memory that stores the program. (b) It includes a processing device and a program storage device that execute part of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing. (c) A dedicated hardware circuit is provided to execute all of the above processing. Here, there may be a plurality of software processing circuits including a processing device and a program storage device, and a plurality of dedicated hardware circuits. That is, the above processing may be executed by a processing circuit including at least one of one or more software processing circuits and one or more dedicated hardware circuits.

10... Cooling device 12... Radiator 15... Internal combustion engine 15W... Water jacket 16... First passage 17... Second passage 18... Water pump 20... Branch passage 25... Thermostat 34... Water temperature sensor 35... Outside temperature sensor 100... Control device 110 ...Central processing unit (CPU)
120...Memory 130...Communication device 200...Network 300...Data analysis device 310...CPU
320...Memory 330...Communication device 500...Vehicle 600...Vehicle

Claims (5)

A system for estimating deterioration of cooling water for an internal combustion engine,
Equipped with an execution device,
The execution device includes:
an acquisition process for acquiring data regarding the heat reception history of the cooling water;
an estimation process that estimates the deterioration based on the data;
Heat reception history estimation for estimating the heat reception history of the cooling water while the operation of the execution device is stopped based on stop information including the temperature of the cooling water and the outside air temperature at the time when the operation of the execution device is stopped when the engine is stopped. cooling water deterioration estimation system. The heat reception history is a cumulative time for each cooling water temperature,
The cooling water deterioration estimation system according to claim 1, wherein the heat reception history estimation process includes a process of calculating the cumulative time based on a functional formula using the stoppage information as an input variable. The functional expression includes a constant,
The execution device calculates the constant based on the stop information, the cooling water temperature at engine start, and the engine stop time from engine stop to engine start as input variables. The cooling water deterioration estimation system according to claim 2. The cooling water deterioration estimation system according to claim 3, wherein the execution device calculates the constant when the stop time is within a predetermined range. Multiple temperature categories are set,
The cooling water deterioration estimation system according to claim 2, wherein the cumulative time for each temperature of the cooling water is the cumulative time for each temperature category.

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