Engine oil change time notification control device

Abstract

To provide an engine oil change time notification control device that can accurately notify a driver in advance of the time to change engine oil.SOLUTION: An engine oil change time notification control device comprises: a heat capacity calculation unit that calculates a heat capacity correlation value correlating with the heat capacity of engine oil for cooling and lubricating an engine mounted on a vehicle; a heat capacity prediction unit that predicts a change in the heat capacity correlation value; a first calculation unit that calculates a first margin value correlating with a first margin time until an engine oil change time on the basis of a prediction result of the heat capacity prediction unit; a viscosity calculation unit that calculates a viscosity correlation value correlating with the viscosity of the engine oil; a viscosity prediction unit that predicts a change in the viscosity correlation value; a second calculation unit that calculates a second margin value correlating with a second margin time until the engine oil change time on the basis of a prediction result of the viscosity prediction unit; and a notification control unit that causes a notification device to notify the smaller of the first and second margin values as the time to change the engine oil.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an engine oil change timing notification control device. [Background technology]

[0002] There is a technique for determining the deterioration state of engine oil (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-032188 Summary of the Invention [Problem to be solved by the invention]

[0004] The above technology does not allow the driver to know in advance when the engine oil needs to be changed, and therefore the driver cannot prepare for the engine oil change in advance.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an engine oil change timing notification control device that can accurately notify the driver in advance of the engine oil change timing. [Means for solving the problem]

[0006] The above object can be achieved by an engine oil change timing notification control device including: a heat capacity calculation unit that calculates a heat capacity correlation value that correlates with the heat capacity of engine oil that cools and lubricates an engine mounted on a vehicle; a heat capacity prediction unit that predicts a change in the heat capacity correlation value; a first calculation unit that calculates a first margin value that correlates with a first margin time until the engine oil change timing based on a prediction result of the heat capacity prediction unit; a viscosity calculation unit that calculates a viscosity correlation value that correlates with the viscosity of the engine oil; a viscosity prediction unit that predicts a change in the viscosity correlation value; a second calculation unit that calculates a second margin value that correlates with a second margin time until the engine oil change timing based on the prediction result of the viscosity prediction unit; and a notification control unit that causes a notification device to notify the smaller of the first and second margin values as the engine oil change timing.

[0007] The heat capacity calculation unit may calculate the heat capacity correlation value for each predetermined workload of the engine, and the heat capacity prediction unit may select, from a plurality of heat capacity trend lines showing trends in the heat capacity correlation value, the heat capacity trend line that approximates the calculated plurality of heat capacity correlation values, and the first calculation unit may calculate the first margin value based on the selected heat capacity trend line.

[0008] The viscosity calculation unit may calculate the viscosity correlation value for each predetermined workload of the engine, the viscosity prediction unit may select, from a plurality of viscosity transition lines that indicate transitions in the viscosity correlation value, viscosity transition lines that approximate the calculated plurality of viscosity correlation values, and the second calculation unit may calculate the second margin value based on the selected viscosity transition line.

[0009] The engine may include an oil pan that stores the engine oil, and an engine body to which the engine oil is supplied from the oil pan, and the heat capacity calculation unit may calculate the heat capacity correlation value based on the amount of engine oil circulating within the engine body, the temperature of a combustion chamber of the engine body, and the temperature of a piston of the engine body.

[0010] The heat capacity calculation unit may calculate the circulation amount based on a value obtained by adding the amount of engine oil stored in the oil pan when the engine is stopped to the amount of engine oil remaining in the engine body when the engine is stopped, and subtracting the amount of engine oil stored in the oil pan when the engine is running. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an engine oil change timing notification control device that can accurately notify a driver in advance of the time to change engine oil. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of the engine system. [Figure 2] FIG. 2 is a flowchart illustrating an example of engine oil change timing notification control. [Figure 3] FIG. 3A is a graph illustrating a plurality of calculated heat capacity correlation values, FIG. 3B is a graph illustrating a plurality of heat capacity transition lines, and FIG. 3C is a graph illustrating a selected heat capacity transition line. [Figure 4] FIG. 4A is a graph illustrating a plurality of calculated viscosity correlation values, FIG. 4B is a graph illustrating a plurality of viscosity transition lines, and FIG. 4C is a graph illustrating a selected viscosity transition line. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Vehicle outline] FIG. 1 is a schematic diagram of a vehicle 1 of this embodiment. The vehicle 1 includes an engine 10, a torque converter 30, an automatic transmission 31, a propeller shaft 32, drive wheels 35, an ECU (Electronic Control Unit) 50, and a display device 60. The engine 10 is a driving power source for traveling. The torque converter 30 is a fluid-type power transmission connected to the engine 10. The automatic transmission 31 is connected to the torque converter 30. Power from the engine 10 is transmitted to the automatic transmission 31 via the torque converter 30. The propeller shaft 32 is connected to an output shaft of the automatic transmission 31. The differential gear device 33 is connected to the propeller shaft 32. The drive wheels 35 are connected to the differential gear device 33 via axles 34. The display device 60 is, for example, a liquid crystal display disposed on the dashboard. The display device 60 displays the remaining time until the engine oil needs to be changed, as will be described in detail later.

[0014] The engine 10 includes an engine body 11 and an oil pan 12 fixed to the bottom of the engine body 11. The engine body 11 includes a cylinder block that rotatably supports a crankshaft 13, a cylinder head that defines a combustion chamber (not shown), and a piston 21 that reciprocates within the cylinder block in conjunction with the crankshaft 13. The volume of the combustion chamber 22 increases and decreases due to the reciprocating movement of the piston 21. The oil pan 12 stores engine oil.

[0015] An oil circulation path through which engine oil circulates is formed in the engine body 11. The oil circulation path is provided with an oil pump 14, an oil strainer 15, an oil filter 16, and an OCV (Oil Control Valve) 18. The oil pump 14 draws and discharges engine oil from the oil pan 12 through the oil strainer 15. The oil pump 14 is a mechanical pump that operates in response to the rotation of the crankshaft 13. The OCV 18 opens and closes under the control of the ECU 50. The amount of engine oil discharged from the oil pump 14 is changed by opening and closing the OCV 18.

[0016] The engine oil discharged from the oil pump 14 passes through an oil filter 16 and is then sent to a main gallery 17. The engine oil is supplied from the main gallery 17 to each lubrication part 19 and an oil jet 20 of the engine body 11. The engine oil supplied to each lubrication part 19 and the engine oil sprayed onto the back of the piston 21 by the oil jet 20 are collected in the oil pan 12. In this way, the engine oil lubricates the engine 10. The engine oil also cools the engine 10 by removing heat from each part of the engine 10.

[0017] The ECU 50 is mainly composed of a computer including volatile and non-volatile memories such as a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory). The ECU 50 executes programs installed in the memory on the CPU to realize various control processes related to the engine 10. Various sensors are connected to the ECU 50, which will be described in detail later. The ECU 50 is an example of an engine oil change timing notification control device, and functionally realizes a heat capacity calculation unit, a heat capacity prediction unit, a first calculation unit, a viscosity calculation unit, a viscosity prediction unit, a second calculation unit, and a notification control unit, which will be described in detail later.

[0018] The ECU 50 is electrically connected to an ignition switch 41, an oil level sensor 42, an oil temperature sensor 43, an oil pressure sensor 44, a combustion chamber temperature sensor 45, a torque sensor 46, and a crank angle sensor 47. The ignition switch 41 detects the on / off state of the ignition. The oil level sensor 42 detects the amount of engine oil stored in the oil pan 12. The oil temperature sensor 43 detects the temperature of the engine oil flowing in the main gallery 17. The oil pressure sensor 44 detects the pressure of the engine oil flowing in the main gallery 17. The combustion chamber temperature sensor 45 detects the temperature in the combustion chamber. The torque sensor 46 detects the output torque of the crankshaft 13. The crank angle sensor 47 detects the rotation speed of the crankshaft 13.

[0019] [Engine oil change notification control] Next, the engine oil change time notification control will be described. Fig. 2 is a flowchart illustrating the engine oil change time notification control. The engine oil change time notification control is repeatedly executed while the ignition switch 41 is in the on state.

[0020] The ECU 50 calculates a heat capacity correlation value of the engine oil for each predetermined workload of the engine 10 (step S1). The heat capacity correlation value is a value that correlates with the heat capacity of the engine oil and is proportional to the heat capacity of the engine oil. The heat capacity of the engine oil corresponds to the cooling capacity of the engine oil. This is because the larger the heat capacity of the engine oil, the greater the amount of heat that the engine oil removes from the engine 10, indicating a higher cooling capacity of the engine oil. The heat capacity correlation value is a value that correlates with the heat capacity, but may be the heat capacity itself. The workload of the engine 10 is calculated based on the rotation speed and output torque of the crankshaft 13. Step S1 is an example of processing executed by the heat capacity calculation unit.

[0021] The heat capacity correlation value is calculated based on the amount of engine oil circulating within the engine body 11, the temperature of the combustion chamber of the engine body 11, and the temperature of the piston of the engine body 11. The amount of circulation is calculated by adding the amount of engine oil remaining in the engine body 11 when the engine 10 is stopped to the amount of engine oil stored in the oil pan 12 when the engine 10 is stopped, and subtracting the amount of engine oil stored in the oil pan 12 when the engine 10 is running. The amount of stored oil is detected by the oil level sensor 42. The amount of remaining oil is obtained in advance through experiments and stored in the ROM of the ECU 50. The temperature of the combustion chamber is detected by the combustion chamber temperature sensor 45. The temperature of the piston is correlated with the temperature of the combustion chamber in advance through experiments and stored in the ROM of the ECU 50. For example, the greater the amount of circulation, the lower the temperature of the combustion chamber, and the higher the temperature of the piston, the lower the calculated heat capacity correlation value.

[0022] FIG. 3A is a graph showing an example of a plurality of calculated heat capacity correlation values. The vertical axis represents the heat capacity correlation value, and the horizontal axis represents time. As shown, the heat capacity correlation value, which indicates the cooling capacity of the engine oil, gradually decreases. The lower limit value in FIG. 3A is the heat capacity correlation value at which the engine oil should be replaced.

[0023] Next, the ECU 50 predicts the transition of the heat capacity correlation value (step S2). More specifically, from a plurality of heat capacity transition lines showing the transition of the heat capacity correlation value, a heat capacity transition line that approximates the calculated plurality of heat capacity correlation values is selected. The plurality of heat capacity transition lines are previously obtained through experiments and stored in the ROM of the ECU 50. These heat capacity transition lines are obtained through experiments for each type of engine oil, for example. FIG. 3B is a graph illustrating a plurality of heat capacity transition lines L1 to L4. The ECU 50 selects, from the heat capacity transition lines L1 to L4, a heat capacity transition line that is most approximate to the calculated plurality of heat capacity correlation values. For example, the heat capacity transition line is selected by an arithmetic process such as a nonlinear least squares method. Step S2 is an example of a process executed by the heat capacity prediction unit.

[0024] Next, the ECU 50 calculates a first margin time based on the predicted result of the transition of the heat capacity correlation value (step S3). The first margin time is the margin time until the timing of changing the engine oil, calculated based on the predicted result of the transition of the heat capacity correlation value. FIG. 3C is a graph illustrating an example of the selected heat capacity transition line L2. As shown in FIG. 3C, the time from the calculation of the latest heat capacity correlation value to the intersection of the heat capacity transition line L2 and the lower limit value corresponds to the first margin time. Note that the ECU 50 may correct the selected heat capacity transition line L2 based on the calculated heat capacity correlation value, and calculate the first margin time based on the corrected heat capacity transition line. Step S3 is an example of processing executed by the first calculation unit.

[0025] In this embodiment, the heat capacity transition line that most closely resembles the calculated heat capacity correlation values is selected from the heat capacity transition lines L1 to L4 obtained in advance by experiment, as described above. It is also possible to calculate the heat capacity transition line based on the calculated heat capacity correlation values and calculate the first margin time based on the calculated heat capacity transition line. However, because there are multiple factors that can cause the heat capacity of engine oil to decrease, calculating the heat capacity transition line without using experimental results may result in a deviation from the actual heat capacity transition, reducing the accuracy of the calculation of the first margin time. Therefore, by selecting the heat capacity transition line from the heat capacity transition lines L1 to L4 obtained in advance by experiment, as in this embodiment, the accuracy of the calculation of the first margin time is improved. The same applies to the viscosity transition line described below.

[0026] Next, the ECU 50 calculates a viscosity correlation value for each predetermined workload of the engine 10 (step S4). The viscosity correlation value is a correlation value that correlates with the viscosity of the engine oil and is a value that is proportional to the viscosity of the engine oil. The viscosity of the engine oil corresponds to the lubricating ability of the engine oil. This is because the lower the viscosity of the engine oil, the more sufficiently the engine oil can lubricate the engine 10. The viscosity correlation value is a value that correlates with the viscosity, but may also be the viscosity itself. Step S4 is an example of processing executed by the viscosity calculation unit.

[0027] The viscosity correlation value is calculated based on the temperature and pressure of the engine oil and the output torque of the engine 10. The temperature and pressure of the engine oil are detected by the oil temperature sensor 43 and the oil pressure sensor 44, respectively. The output torque of the engine 10 is detected by the torque sensor 46. For example, the lower the engine oil temperature and the higher the engine oil pressure, the higher the calculated viscosity correlation value. Furthermore, the larger the difference between the output torque of the engine 10 detected by the torque sensor 46 and the output torque of the engine 10 obtained in advance by experiment, the higher the calculated viscosity correlation value. This is because the larger the difference, the higher the viscosity of the engine oil is that is higher than the optimum value.

[0028] Figure 4A is a graph showing an example of multiple calculated viscosity correlation values. As shown, the viscosity correlation value indicating the lubricating ability of the engine oil gradually increases. The upper limit value in Figure 4A is the viscosity correlation value at which the engine oil should be replaced.

[0029] Next, the ECU 50 predicts the transition of the viscosity correlation value (step S5). More specifically, from a plurality of viscosity transition lines showing the transition of the viscosity correlation value, a viscosity transition line that approximates the calculated plurality of viscosity correlation values is selected. For example, the viscosity transition line is selected by calculation processing such as the nonlinear least squares method. The plurality of viscosity transition lines are obtained in advance by experiments and stored in the ROM of the ECU 50. These viscosity transition lines are obtained by experiments for each type of engine oil, for example. FIG. 4B is a graph illustrating a plurality of viscosity transition lines L5 to L8. The ECU 50 selects from the viscosity transition lines L5 to L8 a viscosity transition line that approximates the calculated plurality of viscosity correlation values. Step S5 is an example of processing executed by the viscosity prediction unit.

[0030] Next, the ECU 50 calculates a second margin time based on the predicted transition of the viscosity correlation value (step S6). The second margin time is the margin time until the engine oil is changed, calculated based on the predicted transition of the viscosity correlation value. FIG. 4C is a graph illustrating an example of the selected viscosity transition line L6. As shown in FIG. 4C, the time from when the latest viscosity correlation value is calculated to the intersection of the viscosity transition line L6 and the upper limit value corresponds to the second margin time. Note that the ECU 50 may correct the selected viscosity transition line L6 based on the calculated viscosity correlation value, and calculate the second margin time based on the corrected viscosity transition line. Step S6 is an example of processing executed by the second calculation unit.

[0031] Next, the ECU 50 determines whether the second margin time is longer than the first margin time (step S7). If the answer is Yes in step S7, the ECU 50 causes the display device 60 to display the first margin time (step S8). If the answer is No in step S7, the ECU 50 causes the display device 60 to display the second margin time (step S9). In this way, the shorter of the first and second margin times is displayed on the display device 60. This allows the driver to know in advance when it is time to change the engine oil. Therefore, the driver can make preparations for changing the engine oil in advance. Steps S8 and S9 are an example of processing executed by the notification control unit.

[0032] Here, the display device 60 is an example of a notification device. The notification device may be, for example, a speaker mounted on a vehicle or a speaker of a car navigation system. The shorter of the first and second margin times may be output from the speaker.

[0033] The above-mentioned first and second margin times are examples of first and second margin values, respectively. For example, first and second travel distances that can be traveled may be calculated as the first and second margin values.

[0034] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0035] 1 vehicle 10 Engine 11 Engine body 12 Oil pan 50 ECU (engine oil change timing notification control device, heat capacity calculation unit, heat capacity prediction unit, first calculation unit, viscosity calculation unit, viscosity prediction unit, second calculation unit, notification control unit) 60 Display device (alarm device)

Claims

1. a heat capacity calculation unit that calculates a heat capacity correlation value that correlates with the heat capacity of engine oil that cools and lubricates an engine mounted on a vehicle; a heat capacity prediction unit that predicts a transition of the heat capacity correlation value; a first calculation unit that calculates a first margin value that correlates with a first margin time until the engine oil is changed based on a prediction result of the heat capacity prediction unit; a viscosity calculation unit that calculates a viscosity correlation value that correlates with the viscosity of the engine oil; a viscosity prediction unit that predicts a transition of the viscosity correlation value; a second calculation unit that calculates a second margin value that correlates with a second margin time until the engine oil is changed based on a prediction result of the viscosity prediction unit; a notification control unit that causes a notification device to notify the smaller of the first and second margin values as the engine oil change time; An engine oil change notification control device comprising:

2. the heat capacity calculation unit calculates the heat capacity correlation value for each predetermined workload of the engine, the heat capacity prediction unit selects, from a plurality of heat capacity transition lines showing transitions of the heat capacity correlation values, the heat capacity transition line that approximates the calculated plurality of heat capacity correlation values; 2. The engine oil change timing notification control device according to claim 1, wherein the first calculation unit calculates the first margin value based on the selected heat capacity transition line.

3. the viscosity calculation unit calculates the viscosity correlation value for each predetermined workload of the engine, the viscosity prediction unit selects, from a plurality of viscosity transition lines that indicate transitions of the viscosity correlation value, the viscosity transition line that approximates the calculated plurality of viscosity correlation values; 3. The engine oil change timing notification control device according to claim 2, wherein the second calculation unit calculates the second margin value based on the selected viscosity transition line.

4. the engine includes an oil pan that stores the engine oil, and an engine body to which the engine oil is supplied from the oil pan, 4. The engine oil change timing notification control device according to claim 1, wherein the heat capacity calculation unit calculates the heat capacity correlation value based on the amount of engine oil circulating within the engine body, the temperature of a combustion chamber of the engine body, and the temperature of a piston of the engine body.

5. 5. The engine oil change timing notification control device of claim 4, wherein the heat capacity calculation unit calculates the circulating amount based on a value obtained by adding the amount of engine oil stored in the oil pan when the engine is stopped to the amount of engine oil remaining in the engine body when the engine is stopped, and subtracting the amount of engine oil stored in the oil pan when the engine is running.

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