Oil deterioration determination device for internal combustion engine

Abstract

To solve a problem that when a reference parameter cannot be acquired normally, an index value indicating a deterioration level of engine oil cannot be calculated.SOLUTION: In acquisition processing, a control device acquires a fuel injection amount FA and a cooling water temperature TW of an internal combustion engine as reference parameters. In index value calculation processing, the control device calculates a residual travelable distance RD that is an index value indicating a deterioration level of engine oil on the basis of the acquired reference parameter. In the case where one or more of the reference parameters cannot be acquired normally in the acquisition processing, in the index value calculation processing, the control device calculates, instead of the reference parameter that cannot be acquired normally, the residual travelable distance RD on the basis of a predetermined alternative parameter corresponding to the reference parameter.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an oil deterioration determining device for an internal combustion engine. [Background technology]

[0002] The oil deterioration determination device for an internal combustion engine in Patent Document 1 is capable of calculating the amount of sludge precursors accumulated in engine oil. This oil deterioration determination device refers to the fuel injection amount and the cooling water temperature of the internal combustion engine when calculating the amount of sludge precursors accumulated. Then, when the amount of sludge precursors accumulated exceeds an upper limit, the oil deterioration determination device issues a warning to the driver or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5811183 Summary of the Invention [Problem to be solved by the invention]

[0004] In the oil deterioration determination device of Patent Document 1, if the fuel injection amount and the coolant temperature of the internal combustion engine cannot be obtained or if these parameters are abnormal values, the accumulated amount of sludge precursors cannot be calculated. However, Patent Document 1 does not consider at all what measures should be taken when such a situation occurs. [Means for solving the problem]

[0005] One aspect for solving the above problem is an oil deterioration determination device for an internal combustion engine, which is capable of executing an acquisition process for acquiring a fuel injection amount and a coolant temperature of an internal combustion engine as reference parameters, an index value calculation process for calculating an index value indicating a deterioration level of engine oil based on the acquired reference parameters, and a notification process for outputting a notification signal when a mileage after engine oil replacement is equal to or greater than a specified value and the index value is within a predetermined range indicating a high degree of deterioration, and when one or more of the reference parameters cannot be acquired normally in the acquisition process, the index value calculation process calculates the index value based on a predetermined alternative parameter corresponding to the reference parameter instead of the reference parameter that could not be acquired normally. Note that a machine learning model can be used to calculate the index value. Effect of the Invention

[0006] According to the above configuration, even if the reference parameters cannot be normally acquired, the index value indicating the degree of deterioration of the engine oil can be calculated. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of an internal combustion engine and a control device. [Diagram 2] FIG. 2 is a flowchart relating to the engine oil deterioration determination control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] <Configuration of an internal combustion engine> As shown in Fig. 1, an internal combustion engine 10 mounted on a vehicle includes four cylinders 11, four fuel injection valves 12, four spark plugs 13, and a crankshaft 14. Each cylinder 11 is a space for burning a mixture of fuel and intake air. Although not shown in the figure, each cylinder 11 houses a piston that can reciprocate within the cylinder 11 as the mixture is burned.

[0009] Each fuel injection valve 12 injects fuel into a corresponding cylinder 11. The spark plug 13 ignites the air-fuel mixture by spark discharge. The crankshaft 14 is connected to the pistons via connecting rods (not shown). The crankshaft 14 rotates as the pistons reciprocate.

[0010] The internal combustion engine 10 includes an intake pipe 21 and a throttle valve 22. The intake pipe 21 branches into four pipes on the downstream side. Each branch of the intake pipe 21 is connected to each cylinder 11. The throttle valve 22 is located upstream of a branch point of the intake pipe 21. The throttle valve 22 adjusts the amount of intake air flowing through the intake pipe 21.

[0011] The internal combustion engine 10 includes an exhaust pipe 26, a three-way catalyst 27, and a filter 28. The exhaust pipe 26 branches into four on the upstream side. Each branch of the exhaust pipe 26 is connected to each cylinder 11. The three-way catalyst 27 is located downstream of a branch point in the exhaust pipe 26. The three-way catalyst 27 purifies the exhaust gas. The filter 28 is located downstream of the three-way catalyst 27 in the exhaust pipe 26. The filter 28 collects particulate matter contained in the exhaust gas.

[0012] The internal combustion engine 10 includes an oil pan 31 and an oil pump 32. The oil pan 31 is capable of storing engine oil therein for lubricating various parts of the internal combustion engine 10. The oil pump 32 is connected to the crankshaft 14. Thus, the oil pump 32 is a mechanical pump that discharges engine oil in conjunction with the rotation of the crankshaft 14. The oil pump 32 pumps the engine oil to various parts of the internal combustion engine 10. The engine oil that has been supplied to various parts of the internal combustion engine 10 flows back to the oil pan 31.

[0013] <Configuration of control device, etc.> As shown in Fig. 1, the control device 50 includes a CPU 51, a RAM 52, and a storage 53. The CPU 51 is capable of executing various programs. The RAM 52 is a volatile memory. The RAM 52 is a working memory for the CPU 51. The storage 53 is a non-volatile memory. The storage 53 stores the programs executed by the CPU 51 and data to be retained even after the power of the control device 50 is turned off.

[0014] The control device 50 acquires the coolant temperature TW from the coolant temperature sensor 61 of the internal combustion engine 10. The coolant temperature TW reflects the temperature of the internal combustion engine 10. The control device 50 acquires the intake air temperature TA from the intake air temperature sensor 62. The control device 50 acquires the intake air amount GA from the air flow meter 63. The control device 50 acquires the crank angle CA from the crank angle sensor 64. The control device 50 calculates the number of revolutions NE of the crankshaft 14 per unit time based on the crank angle CA. The control device 50 calculates the fuel injection amount FA in accordance with the operating conditions of the internal combustion engine 10. The calculated fuel injection amount FA is stored in the RAM 52 for a certain period of time.

[0015] <Engine oil deterioration judgment control> In this embodiment, the control device 50 functions as an oil deterioration determination device for the internal combustion engine 10. The control device 50 repeatedly executes the following engine oil deterioration determination control at every predetermined control period.

[0016] As shown in Fig. 2, when the deterioration determination control is started, the control device 50 executes the process of step S11. In step S11, the control device 50 acquires, as reference parameters, a plurality of fuel injection amounts FA during the control cycle and the latest cooling water temperature TW at the time of step S11. The process of step S11 is an acquisition process. After that, the process of the control device 50 proceeds to step S12.

[0017] In step S12, the control device 50 judges whether the cooling water temperature TW has been acquired normally. The state where the cooling water temperature TW has not been acquired normally refers to a case where the cooling water temperature TW has not been acquired, and a case where the cooling water temperature TW has been acquired but its value is outside the detectable range of the cooling water temperature sensor 61. If the determination in step S12 is affirmative, the processing of the control device 50 proceeds to step S14. If the determination in step S12 is negative, the processing of the control device 50 proceeds to step S13. In step S13, the control device 50 sets the cooling water temperature TW that has not been acquired normally as the intake air temperature TA, which is an alternative parameter. After that, the processing of the control device 50 proceeds to step S14.

[0018] In step S14, the control device 50 judges whether or not all of the fuel injection amounts FA during the control cycle have been acquired normally. The state in which the fuel injection amounts FA have not been acquired normally refers to a case in which some or all of the fuel injection amounts FA have not been acquired, and a case in which the fuel injection amount FA has been acquired but its value is outside the range that the fuel injection amount FA can take. If the judgment in step S14 is affirmative, the processing of the control device 50 proceeds to step S16. If the judgment in step S14 is negative, the processing of the control device 50 proceeds to step S15.

[0019] In step S15, the control device 50 calculates the alternative injection amount FX based on the rotation speed NE and the intake air amount GA. At this time, the control device 50 calculates the alternative injection amount FX to be larger as the rotation speed NE is larger and as the intake air amount GA is larger. Then, the control device 50 sets the fuel injection amount FA that could not be normally acquired as the alternative injection amount FX as an alternative parameter. After that, the process of the control device 50 proceeds to step S16.

[0020] In step S16, the control device 50 calculates the amount of oil deterioration during the control cycle. At this time, the control device 50 calculates the amount of oil deterioration to be greater the smaller the cooling water temperature TW is and the greater the total fuel injection amount FA during the control cycle is. After that, the process of the control device 50 proceeds to step S17.

[0021] In step S17, the control device 50 calculates the remaining drivable distance RD as an index value indicating the deterioration degree of the engine oil. Specifically, the control device 50 first converts the amount of oil deterioration calculated in step S16 into a mileage based on a predetermined relational expression, map, etc. At this time, the control device 50 calculates a larger mileage as the amount of oil deterioration increases. Then, the control device 50 subtracts the above-mentioned mileage from the remaining drivable distance RD calculated in the previous control cycle to calculate a new remaining drivable distance RD. The newly calculated remaining drivable distance RD is stored in the storage 53. Note that an initial value of the remaining drivable distance RD is previously determined. For example, the initial value of the remaining drivable distance RD is several thousand kilometers. The processes of steps S16 and S17 are index value calculation processes. Thereafter, the process of the control device 50 proceeds to step S18.

[0022] In step S18, the control device 50 judges whether the remaining drivable distance RD is less than zero, and whether the post-exchange drivable distance TD, which is the drivable distance after the engine oil has been changed, exceeds a predetermined specified value X. The remaining drivable distance RD being less than zero is synonymous with the remaining drivable distance RD being within a range indicating a high degree of deterioration. The specified value X is, for example, several thousand kilometers. If at least one of the above two judgments is a negative judgment, the series of oil deterioration judgment controls ends. On the other hand, if both of the above two judgments are positive judgments, the processing of the control device 50 proceeds to step S19.

[0023] In step S19, the control device 50 outputs a notification signal to notify the driver, etc. of the oil change. This notification signal is received by an indicator lamp, a display, etc., and the driver, etc. is notified. The processes of steps S18 and S19 are notification processes. Thereafter, a series of oil deterioration determination controls is terminated.

[0024] <Effects of the embodiment> (1) According to the above embodiment, when the cooling water temperature TW cannot be acquired normally, the intake air temperature TA is used as an alternative parameter. When the fuel injection amount FA cannot be acquired normally, the alternative injection amount FX is used as an alternative parameter. By compensating for the reference parameter that has not been acquired normally with the alternative parameter in this way, the control device 50 can calculate the amount of oil deterioration and the remaining driving distance RD.

[0025] (2) In the above embodiment, the intake air temperature TA is used as an alternative parameter for the cooling water temperature TW. The minimum value that the cooling water temperature TW can take is approximately the intake air temperature TA. Therefore, by calculating the remaining driving distance RD using the intake air temperature TA as an alternative parameter, it is possible to reduce the risk of calculating a remaining driving distance RD that is greater than the actual value.

[0026] (3) In the above embodiment, the alternative injection amount FX is used as an alternative parameter for the fuel injection amount FA. This alternative injection amount FX is calculated based on the rotation speed NE and the intake air amount GA, and is therefore a value that is close to the fuel injection amount FA. Therefore, even if the fuel injection amount FA cannot be obtained normally, it is possible to calculate a value that is close to the remaining driving distance RD that would be obtained if the fuel injection amount FA could be obtained normally.

[0027] <Example of change> This embodiment can be modified as follows: Furthermore, this embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0028] The configuration of the internal combustion engine 10 in the above embodiment is an example. For example, the number of cylinders 11 of the internal combustion engine 10 may be three or less or five or more. In addition, the internal combustion engine 10 may have an EGR mechanism for recirculating a portion of the exhaust gas to the intake side.

[0029] The oil pump 32 is not limited to a mechanical pump. That is, the oil pump 32 may be an electric pump. Instead of the control device 50 executing the process of step S16 and subsequent steps of the oil deterioration determination control, an external server or the like that can communicate with the control device 50 may execute the process of step S16 and subsequent steps. In this case, for example, the control device 50 may calculate alternative parameters, compensate for reference parameters that could not be properly acquired with the alternative parameters, and then transmit a data set of the series of parameters to the external server or the like.

[0030] The alternative parameter for the coolant temperature TW is not limited to the intake air temperature TA. For example, the alternative parameter for the coolant temperature TW may be a value that can be derived from a parameter other than the coolant temperature TW. Furthermore, the alternative parameter for the coolant temperature TW may be a fixed value. In this case, the fixed value may be, for example, a value equivalent to the ambient air temperature, such as 27 degrees, or may be the lower detection limit value of the intake air temperature sensor 62, such as -40 degrees.

[0031] When calculating the alternative injection amount FX, the relational expression, map, etc. for calculating the alternative injection amount FX may be learned while the internal combustion engine 10 is operating normally. Specifically, for example, even if the fuel injection amount FA, which is a reference parameter, can be acquired normally, the alternative injection amount FX is calculated using the relational expression. Then, the coefficients, etc. in the relational expression may be changed so that the calculated alternative injection amount FX coincides with the fuel injection amount FA that has been acquired normally.

[0032] The method of calculating the alternative injection amount FX is not limited to the example of the above embodiment. For example, the alternative injection amount FX may be calculated based only on the engine speed NE, or the alternative injection amount FX may be calculated using other parameters instead of or in addition to the engine speed NE and the intake air amount GA. Examples of the other parameters include the engine load rate, the EGR rate, and the time during which the fuel cut process is performed.

[0033] The alternative injection amount FX may be a fixed value. In this case, the fixed value may be the maximum value that the fuel injection amount FA can take, or may be the fuel injection amount FA during idling operation of the internal combustion engine 10.

[0034] Any of the reference parameters that were successfully acquired may be used as the substitute parameter value. For example, if the fuel injection amount FA cannot be successfully acquired, the most recently successfully acquired value of the fuel injection amount FA may be used as the substitute parameter value.

[0035] In this way, the alternative parameter may be a fixed value or a variable value. Even if it is a variable value, it can be said to be a predetermined alternative parameter if the calculation method is determined in advance.

[0036] The method of calculating the oil deterioration amount and the method of calculating the remaining driving distance RD are not limited. For example, the oil deterioration amount may be calculated using other parameters instead of or in addition to the coolant temperature TW and the fuel injection amount FA. Examples of the other parameters include the rotation speed NE and the oil discharge amount of the oil pump 32. Also, a machine learning model may be used that uses the coolant temperature TW and the fuel injection amount FA as input variables and outputs an index value indicating the degree of engine oil deterioration. In this case, the machine learning model may be a supervised trained model in which learning is performed with the correct answer given to the learning data.

[0037] The index value showing the deterioration level of the engine oil is not limited to the remaining driving distance RD. Any index value that is correlated with the deterioration level may be used as appropriate. [Explanation of symbols]

[0038] 10...Internal combustion engine FA...Fuel injection amount TW...Cooling water temperature RD...Remaining travel distance TD...Midage distance after replacement TA...Intake temperature FX...Alternative injection amount

Claims

[Claim 1] An acquisition process of acquiring a fuel injection amount and a coolant temperature of the internal combustion engine as reference parameters; An index value calculation process for calculating an index value indicating a deterioration degree of the engine oil based on the acquired reference parameters; a notification process for outputting a notification signal when the mileage after the engine oil change is equal to or greater than a specified value and the index value is within a predetermined range indicating that the degree of deterioration is high; It is possible to execute If one or more of the reference parameters cannot be normally acquired in the acquisition process, the index value calculation process calculates the index value based on a predetermined alternative parameter corresponding to the reference parameter that cannot be normally acquired. An oil deterioration detection device for internal combustion engines.

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