Oil level adjustment device

Abstract

To provide a vehicle control device that can improve the ease of work in oil level adjustment.SOLUTION: An oil level adjusting device comprises a valve provided in a cooling water passage through which cooling water flows, a first heat exchanger that is connected to the cooling water passage and in which heat exchange occurs between the cooling water and hydraulic oil, an adjustment unit for adjusting the amount of hydraulic oil in a power transmission device, and a control unit for controlling the valve. When adjusting the amount of hydraulic oil in the power transmission device, the control unit controls the opening of the valve so that the flow rate of the cooling water to the first heat exchanger becomes constant.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an oil level adjusting device.

Background Art

[0002] Vehicles are equipped with an internal combustion engine and a transmission. The transmission is filled with hydraulic oil (oil) (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Work is carried out to appropriately adjust the amount of oil (oil volume, oil level) in the transmission. By the way, depending on the temperature, the viscosity and volume of the oil change. When the temperature of the oil (oil temperature) is within an appropriate range, the oil level is adjusted. When the oil exchanges heat with the cooling water, the temperature of the oil changes. Due to the change in the oil temperature caused by heat exchange, the oil temperature is likely to deviate from the range suitable for oil level adjustment. The time required for the adjustment work becomes shorter, and the work becomes difficult. Therefore, an object of the present invention is to provide an oil level adjusting device capable of improving the workability of oil level adjustment.

Means for Solving the Problems

[0005] The above objective is achieved by a power transmission device comprising: a valve provided in a cooling water passage through which cooling water flows; a first heat exchanger connected to the cooling water passage, through which the cooling water and hydraulic oil perform heat exchange; an adjustment unit for adjusting the amount of hydraulic oil in the power transmission device; and a control unit for controlling the valve. When adjusting the amount of hydraulic oil in the power transmission device, the control unit can achieve this by controlling the opening degree of the valve so that the flow rate of the cooling water to the first heat exchanger remains constant.

[0006] When adjusting the amount of hydraulic fluid in the power transmission device, the control unit may control the opening of the valve so that the cooling water does not flow into the first heat exchanger.

[0007] The power transmission device is equipped with a second heat exchanger connected to the cooling water passage, and when adjusting the amount of hydraulic fluid in the power transmission device, and the temperature of the cooling water is above a predetermined temperature, the control unit may control the valve so that the cooling water flows into the second heat exchanger.

[0008] The system may also include a notification unit that notifies the user to discontinue adjusting the amount of hydraulic fluid if the temperature of the cooling water is higher than a predetermined temperature or higher than the temperature of the hydraulic fluid. [Effects of the Invention]

[0009] We can provide an oil level adjustment device that improves the workability of oil level adjustment. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram of the vehicle according to the first embodiment. [Figure 2] Figure 2 is a flowchart illustrating the process in the first embodiment. [Figure 3] Figures 3(a) and 3(b) illustrate time charts. [Figure 4]Figure 4(a) is a flowchart illustrating the process in the second embodiment. Figure 4(b) is a diagram illustrating the time chart in the second embodiment. [Figure 5] Figure 5 is a flowchart illustrating the process in the third embodiment. [Figure 6] Figure 6 is a flowchart illustrating the process in the fourth embodiment. [Modes for carrying out the invention]

[0011] <First Embodiment> Figure 1 is a schematic diagram illustrating a vehicle 1 according to the first embodiment. The vehicle 1 includes an internal combustion engine 10, a power transmission device 12, an oil cooler 14 (first heat exchanger), a radiator 16 (second heat exchanger), a fan 18, an oil pump 20, a coolant pump 22, a heater 24, a solenoid valve 26, a notification unit 39, and an ECU (Electronic Control Unit) 40. The oil level adjustment device is applied to the vehicle 1 and includes an oil cooler 14, a radiator 16, an oil pump 20, a solenoid valve 26, a notification unit 39, and an ECU 40.

[0012] The internal combustion engine 10 burns fuel, such as gasoline, to produce power. The vehicle 1 is driven by the power produced by the internal combustion engine 10. The power transmission device 12 includes, for example, a transmission and is connected to the crankshaft of the internal combustion engine 10. The power transmission device 12 transmits the power generated by the internal combustion engine 10 to the wheels and the like. The rotation of the internal combustion engine 10 drives the oil pump 20 and the coolant pump 22.

[0013] The cooling water pump 22 is connected to one end each of the cooling water passages 30, 34, and 35. The internal combustion engine 10 is provided with a water jacket (not shown). The other end of the cooling water passage 30 and one end of the cooling water passage 32 are connected to the water jacket. A heater 24 is provided in the middle of the cooling water passage 34. The other end of the cooling water passage 34 is connected to a solenoid valve 26. The other end of the cooling water passage 32 is connected to a solenoid valve 26. A radiator 16 is provided in the middle of the cooling water passage 35. The other end of the cooling water passage 35 is connected to a solenoid valve 26. The cooling water passage 37 is connected to a solenoid valve 26 and an oil cooler 14.

[0014] The oil passage 38 is connected to the oil pump 20 and the power transmission device 12. An oil cooler 14 is provided in the middle of the oil passage 38. Oil (hydraulic fluid) flows through the oil passage 38.

[0015] The cooling water pump 22 circulates the cooling water. The cooling water flows through the cooling water passage 30 and is supplied to the water jacket of the internal combustion engine 10. After cooling the internal combustion engine 10, the cooling water is discharged from the internal combustion engine 10 and flows through the cooling water passage 32.

[0016] The solenoid valve 26 functions as a switching unit that switches the flow path of the cooling water. The solenoid valve 26 can independently open and close each of the cooling water passages 34, 35, and 37. When the solenoid valve 26 opens the cooling water passage 34, the cooling water flows through the cooling water passage 34 and is introduced to the heater 24. The cooling water undergoes heat exchange in the heater 24 and returns to the cooling water pump 22.

[0017] When the solenoid valve 26 opens the coolant passage 35, the coolant flows through the coolant passage 35 and is introduced into the radiator 16. The coolant exchanges heat in the radiator 16 and returns to the coolant pump 22. The flow rate of coolant to the radiator 16 changes depending on the opening degree of the solenoid valve 26. When the solenoid valve 26 closes the coolant passage 35, the coolant stops flowing into the radiator 16.

[0018] When the solenoid valve 26 opens the cooling water passage 37, the cooling water flows through the cooling water passage 37. The cooling water exchanges heat with the oil in the oil cooler 14 and returns to the cooling water pump 22. The flow rate of the cooling water to the oil cooler 14 changes according to the opening degree of the solenoid valve 26. When the solenoid valve 26 closes the cooling water passage 37, the cooling water stops flowing into the oil cooler 14.

[0019] The oil passage 38 is connected to the oil pump 20, the oil cooler 14, and the power transmission device 12. The oil pump 20 circulates the oil. The oil exchanges heat with the cooling water in the oil cooler 14 and becomes hotter than before the heat exchange. The oil after the heat exchange flows through the oil passage 38 and is introduced into the power transmission device 12. The oil discharged from the power transmission device 12 is introduced into the oil cooler 14.

[0020] If the amount (oil level) of oil in the power transmission device 12 is too much, the durability of the parts may decrease, and oil blowing may occur. If the oil level is too low, air will be sucked in. It is required to keep the oil level within an appropriate range.

[0021] The ECU 40 includes an arithmetic unit such as a CPU (Central Processing Unit), and storage devices such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The ECU 40 performs various controls by executing programs stored in the ROM and storage devices.

[0022] The temperature sensor 42 detects the temperature of the cooling water (water temperature) in the water jacket. The temperature sensor 44 detects the temperature of the oil (oil temperature) in the power transmission device 12. The ECU 40 acquires the water temperature from the temperature sensor 42 and the oil temperature from the temperature sensor 44. The ECU 40 controls the fan 18. When the fan 18 is driven to send wind, the internal combustion engine 10 is cooled. The notification unit 39 is, for example, a display, a microphone, or a lamp. The ECU 40 controls and operates the notification unit 39.

[0023] The ECU 40 controls the rotational speeds of the internal combustion engine 10, the oil pump 20, and the coolant pump 22. The higher the rotational speed of the oil pump 20, the greater the oil flow rate. The lower the rotational speed of the oil pump 20, the greater the oil flow rate. The ECU 40 controls the oil pump 20 and functions as an adjustment unit to regulate the amount of oil in the power transmission device 12.

[0024] The ECU 40 controls the flow of coolant. The higher the rotational speed of the coolant pump 22, the greater the flow rate of coolant. The lower the rotational speed of the coolant pump 22, the greater the flow rate of coolant. The ECU 40 functions as a control unit that controls the solenoid valve 26, closing and opening the coolant passage.

[0025] Figure 2 is a flowchart illustrating the process in the first embodiment. The ECU 40 determines whether or not to perform an oil level adjustment (step S10). If the determination is negative (No), normal control is performed (step S12). In normal control, for example, the ECU 40 changes the opening degree of the solenoid valve 26 according to the temperature, and controls the flow rate of coolant to the heater 24, oil cooler 14, and radiator 16. If the determination in step S10 is positive (Yes), the ECU 40 sets the opening degree of the port to which the coolant passage 37 of the solenoid valve 26 is connected to a constant (step S14). The flow rate of coolant to the oil cooler 14 becomes constant. This completes the process in Figure 2.

[0026] Figures 3(a) and 3(b) illustrate time charts. The horizontal axis represents time. In Figures 3(a) and 3(b), the first row shows the open / closed state of the solenoid valve 26. The second row shows the flow rate of cooling water to the oil cooler 14. The third row shows the temperature.

[0027] Figure 3(a) shows an example of normal control. At time t1, the solenoid valve 26 transitions from state A1 to A2, and at time t2, it transitions to state A3. In state A1, the solenoid valve 26 is fully closed, and no coolant flows to the heater 24, oil cooler 14, and radiator 16. The coolant circulates through the internal combustion engine 10. In state A2, the solenoid valve 26 opens the coolant passage 34. Coolant flows to the heater 24, but not to the oil cooler 14 and radiator 16. In state A3, the solenoid valve 26 opens the coolant passages 34 and 37. Coolant flows to the heater 24 and oil cooler 14, but not to the radiator 16.

[0028] Prior to time t2, the flow rate of coolant to the oil cooler 14 is zero. At time t2, the solenoid valve 26 opens the coolant passage 37, allowing coolant to flow into the oil cooler 14. The coolant cools, for example, the internal combustion engine 10, so the temperature Tw of the coolant continues to rise. At time t2, when the coolant flows into the oil cooler 14, the oil begins heat exchange with the coolant. The oil temperature To begins to rise.

[0029] The oil level is adjusted within the temperature range of oil temperature To1 to To2. In the example in Figure 3(a), the coolant temperature has risen before time t2. At time t2, the coolant is introduced into the oil cooler 14. As heat exchange occurs between the oil and the high-temperature coolant, the oil temperature To rises rapidly. Due to the steep gradient of the temperature change, the oil temperature To changes quickly from temperature To1 to To2. The period from time t3, corresponding to temperature To1, to time t4, corresponding to temperature To2, becomes shorter. The time required for oil level adjustment is reduced.

[0030] In the example shown in Figure 3(b), the solenoid valve 26 transitions to state A3 at time t5. In state A3, the solenoid valve 26 opens the cooling water passage 37. The opening degree of the solenoid valve 26 is maintained constant (step S14 in Figure 2). The flow rate of cooling water to the oil cooler 14 changes from 0 to F1 and remains constant (F1).

[0031] The oil exchanges heat with the coolant in the oil cooler 14. Before time t5, the coolant temperature is lower than in the example in Figure 3(a). A certain amount of low-temperature coolant is introduced into the oil cooler 14. The rise in oil temperature To is smaller compared to the example in Figure 3(a). As a result, the oil temperature To gradually increases. The oil temperature To reaches To1 at time t6 and To2 at time t7. The oil level is adjusted during the period from time t6 to t7. Because the rise in oil temperature To is small, the period from time t6 to t7 is longer than the period from t3 to t4 in Figure 3(a). The time required for oil level adjustment is longer.

[0032] According to the first embodiment, the ECU 40 drives the oil pump 20 to adjust the amount of oil in the power transmission device 12. When adjusting the oil level, the ECU 40 controls the opening of the solenoid valve 26 so that the flow rate of coolant to the oil cooler 14 remains constant (step S14 in Figure 2). Because the flow rate of coolant is constant, the upward slope of the oil temperature To becomes smaller. The time during which the oil temperature To is in the range of To1 to To2 (from t6 to t7) becomes longer. The time required for oil level adjustment is increased, and work efficiency is improved.

[0033] As shown in Figure 3(b), at time t5, the solenoid valve 26 enters state A3, opening the cooling water passage 37. The opening degree of the solenoid valve 26 is constant. The flow rate of cooling water to the oil cooler 14 is constant. At time t5, the temperature of the cooling water may be below a predetermined temperature. Low-temperature cooling water is introduced into the oil cooler 14 and exchanges heat with the oil. A rapid rise in the oil temperature is suppressed, and the upward slope becomes smaller.

[0034] <Second Embodiment> The same configuration as in the first embodiment will not be explained. Figure 4(a) is a flowchart illustrating the process in the second embodiment. Steps S10 and S12 are the same as the corresponding steps in Figure 2. When adjusting the oil level, the ECU 40 controls the solenoid valve 26 to close the cooling water passage 37 (step S15). This completes the process in Figure 4(a).

[0035] Figure 4(b) illustrates a time chart in the second embodiment. At time t8, the ECU 40 turns on the oil level adjustment mode. The solenoid valve 26 closes the cooling water passage 37. The flow rate of cooling water to the oil cooler 14 is zero. The oil temperature To is To1 at time t9 and To2 at time t10. The oil level adjustment should be performed during the period from t9 to t10.

[0036] According to the second embodiment, the ECU 40 controls the solenoid valve 26 so that coolant does not flow into the oil cooler 14. Since heat exchange between the oil and coolant in the oil cooler 14 is suppressed, the upward slope of the oil temperature To becomes smaller. The time during which the oil temperature To is in the range of To1 to To2 (from t9 to t10) becomes longer. The time required for oil level adjustment is extended, improving work efficiency.

[0037] <Third Embodiment> Descriptions of the same configuration as in either the first or second embodiment will be omitted. Figure 5 is a flowchart illustrating the process in the third embodiment. Steps S10, S12, and S14 are the same as the corresponding steps in Figure 2. After step S14, the ECU 40 obtains the coolant temperature Tw from the temperature sensor 42 and determines whether the temperature Tw is equal to or greater than a predetermined temperature Tth1 (step S16). If the determination is negative, the process ends. If the determination is positive, the ECU 40 controls the solenoid valve 26 to open the coolant passage 35. The coolant flows into the radiator 16 (step S18). After step S18, the process ends.

[0038] According to the third embodiment, when the water temperature Tw is Tth1 or higher, the ECU 40 causes coolant to flow into the radiator 16. The coolant is cooled in the radiator 16. The temperature of the coolant flowing into the oil cooler 14 also decreases. As the coolant temperature decreases, the upward slope of the oil temperature To becomes smaller. The time during which the oil temperature To is in the range of To1 to To2 (from t6 to t7 in Figure 3(b)) becomes longer. The time required for oil level adjustment increases, improving work efficiency.

[0039] <Fourth Embodiment> Descriptions of configurations identical to those in any of the first to third embodiments will be omitted. Figure 6 is a flowchart illustrating the processing in the fourth embodiment. Steps S10 and S12 are the same as the corresponding steps in Figure 2. If the determination in step S10 is positive, the ECU 40 obtains the coolant temperature Tw from the temperature sensor 42 and the oil temperature To from the temperature sensor 44 (step S20). The ECU 40 determines whether the difference Tw-To between the water temperature Tw and the oil temperature To is greater than or equal to a predetermined temperature Tth2 (step S22). If the determination is positive, the ECU 40 notifies the oil level adjustment mode to be turned off and to soak (step S24). The notification is made, for example, using the notification unit 39.

[0040] After step S24, or if a negative determination is made in step S22, the ECU 40 determines whether the oil level adjustment operation has been stopped by the operator (step S26). If the determination is positive, the process ends. If the determination is negative, the oil level adjustment continues. The ECU 40 performs oil temperature control (step S28). For temperature control, the ECU 40 performs steps S14, S16, and S18 in Figure 5, for example. The ECU 40 may also perform step S14 in Figure 2 or step S15 in Figure 4(a).

[0041] According to the fourth embodiment, if the water temperature Tw is higher than the oil temperature To by a predetermined temperature (Tth2), the ECU 40 notifies the operator about the oil level adjustment procedure. For example, a notification such as "Turn off the oil level adjustment mode and lower the temperature" is displayed on the display of the notification unit 39. Alternatively, an audio message is output from the speaker. If the oil level is adjusted while the temperature is high, the time during which the oil temperature To is in the range of To1 to To2 will be shorter. Adjusting the oil level will be difficult. By responding to the notification, the operator can stop adjusting the oil level, thus avoiding unnecessary work. Work efficiency is improved.

[0042] Although preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the invention as described in the claims. [Explanation of symbols]

[0043] 1 vehicle 10 Internal combustion engine 12 Power transmission device 14 Oil cooler 16 Radiator 18 Fans 20 Oil pump 22 Cooling water pump 24 Heater 26 Solenoid valve 30, 34, 35, 37 Cooling water passage 38 Oil passage 39 Notification Department 40 ECU 42, 44 Temperature sensors

Claims

[Claim 1] A valve installed in the cooling water passage through which cooling water flows, An oil cooler connected to the aforementioned cooling water passage, in which the cooling water and hydraulic oil exchange heat, A radiator connected to the aforementioned cooling water passage, A cooling water pump connected to the aforementioned cooling water passage, An internal combustion engine provided with a water jacket connected to the aforementioned cooling water passage, A heater connected to the aforementioned cooling water passage, An adjustment unit for adjusting the amount of hydraulic fluid in a power transmission device, A control unit that controls the valve, The system includes a notification unit that notifies the user to discontinue adjusting the amount of hydraulic fluid if the temperature of the cooling water is higher than the temperature of the hydraulic fluid by a predetermined first temperature or more, The cooling water passage includes a first passage through which cooling water flows from the cooling water pump to the water jacket, a second passage through which cooling water flows from the water jacket to the valve, a third passage connected from the valve to the cooling water pump via the heater, a fourth passage connected from the valve to the cooling water pump via the radiator, and a fifth passage connected from the valve to the fourth passage downstream of the radiator via the oil cooler. When adjusting the amount of hydraulic fluid in the power transmission device and the temperature of the cooling water is below a predetermined second temperature, the control unit controls the opening of the valve to close the fourth passage and open the third and fifth passages so that a certain amount of the cooling water flows to the oil cooler. An oil level adjustment device in which, when adjusting the amount of hydraulic fluid in the power transmission device, the control unit controls the opening of the valve to open the fourth passage so that the coolant flows into the radiator, when the fourth passage is closed, the third and fifth passages are open, and the temperature of the coolant is above the second temperature.

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