JP2018123714A - Oil viscosity estimation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil viscosity estimation device capable of suppressing degradation of estimation accuracy of viscosity of an oil discharged from an oil pump.SOLUTION: A control device 300 as an oil viscosity estimation device is applied to an oil supply device 210 including an oil pump 10, a discharge oil passage 13a in which the oil discharged from the oil pump 10 flows, and a discharge pressure sensor 311 for detecting a pressure of the oil flowing in the discharge oil passage 13a. The control device 300 includes a response time acquiring portion 303 for acquiring a response time as a time required until the convergence of a discharge pressure sensor value to a target discharge pressure from an establishment time of a stipulated condition to determine that the target discharge pressure is different from the discharge pressure sensor value, and a processing portion 304 for estimating that the shorter the acquired response time is, the lower the viscosity of the oil is.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an oil viscosity estimation device that estimates the viscosity of oil discharged from an oil pump.

  When it is determined that the oil discharged from the oil pump and circulating in the engine has deteriorated, a notification for urging oil replacement may be performed. For example, an engine described in Patent Document 1 detects a crank angle sensor that detects an engine rotation speed, a hydraulic pressure sensor that detects oil pressure that is the pressure of oil circulating in the engine, and an oil temperature that is the temperature of oil. And an oil temperature sensor. And the timing which performs said alerting | reporting is determined based on the engine speed, hydraulic pressure, and oil temperature which were detected by each sensor.

  Specifically, an allowable hydraulic pressure range corresponding to the engine speed and the oil temperature is derived. When the hydraulic pressure is higher than the upper limit of the allowable hydraulic pressure range or when the hydraulic pressure is lower than the lower limit of the allowable hydraulic pressure range, the above notification is performed. For example, when unburned fuel that has not been burned in the cylinder of the engine is mixed with the oil and the oil is diluted, the viscosity of the oil becomes low, so the hydraulic pressure tends to be low. When the dilution of the oil proceeds, the hydraulic pressure does not exceed the lower limit of the allowable hydraulic pressure range, and the above notification is performed.

  In addition, the viscosity of oil becomes low, so that oil temperature is high. Therefore, in an oil supply device that performs feedback control using the actual discharge pressure and target discharge pressure of the oil in the oil pump, for example, as described in Patent Document 2, the gain of feedback control is set according to the oil temperature. It is made variable.

JP 2013-199852 A Japanese Patent Application Laid-Open No. 2014-159761

  As an oil supply device that supplies oil circulated in the engine, a hydraulic sensor is disposed in a discharge oil passage through which oil discharged from an oil pump flows, and in order to capture foreign matter upstream of the hydraulic sensor in the discharge oil passage Some devices are provided with a filter. In such a device, when foreign matter is captured by the filter, the pressure loss on the upstream side of the oil pressure sensor in the discharge oil passage is increased, and as a result, the oil pressure detected by the oil pressure sensor is likely to be lowered. Even if a filter is not provided upstream of the hydraulic sensor in the discharge oil passage, if deposits are accumulated upstream of the hydraulic sensor in the discharge oil passage, the pressure loss in the discharge oil passage is still high. Therefore, the oil pressure detected by the oil pressure sensor tends to be low. Therefore, when estimating the viscosity of the oil based on the oil pressure detected by the oil pressure sensor, if the pressure loss on the upstream side of the oil pressure sensor in the discharge oil passage is large, the viscosity estimation accuracy is lowered.

  Further, the viscosity of the oil varies not only with the oil temperature but also with the degree of dilution of the oil. Therefore, even if the feedback control gain is varied according to the oil temperature as described in Patent Document 2, the operation of the oil pump according to the viscosity of the oil is performed when the oil dilution is in progress. It is hard to say that control can be implemented. It is desired to accurately estimate the viscosity of the oil, including when the operation of the oil pump is controlled according to the viscosity of the oil.

  An oil viscosity estimation device for solving the above problems detects an oil pump capable of changing an oil discharge pressure, a discharge oil passage through which oil discharged from the oil pump flows, and a pressure of oil flowing through the discharge oil passage And an oil whose operation is controlled so that the discharge pressure sensor value, which is the oil pressure detected by the sensor, converges to the target discharge pressure, which is the target value of the discharge pressure for the oil pump. Applicable to feeding device. This oil viscosity estimation device obtains a response time that is the time required for the discharge pressure sensor value to converge to the target discharge pressure from the point in time at which the specified condition that allows determination that the target discharge pressure is different from the discharge pressure sensor value is satisfied. A response time acquisition unit, and a processing unit that estimates that the viscosity of the oil is lower as the acquired response time is shorter.

  In a discharge oil passage through which oil discharged from the oil pump flows, pressure loss may increase upstream from the sensor in the discharge oil passage. In the discharge oil passage, when the upstream side of the portion where the pressure loss is large is the upstream passage and the downstream side is the downstream passage, the pressure between the upstream passage and the downstream passage is A differential pressure corresponding to the magnitude of the loss is generated. When the oil discharge pressure in the oil pump changes by a predetermined pressure under the situation where the differential pressure is generated in this way, the hydraulic pressure in the upstream passage and the downstream passage in the downstream passage are maintained in such a manner that the differential pressure is maintained. Both hydraulic pressures change. Therefore, the change speed of the discharge pressure sensor value when changing the discharge pressure sensor value toward the target discharge pressure is not easily influenced by the pressure loss.

  When changing the oil discharge pressure in the oil pump, the lower the oil viscosity, the higher the change rate of the discharge pressure sensor value. Therefore, the lower the oil viscosity, the shorter the time required for the discharge pressure sensor value to converge to the target discharge pressure. Therefore, the length of the response time, which is the time required for the discharge pressure sensor value to converge to the target discharge pressure from the time when the prescribed condition is satisfied, is also hardly influenced by the pressure loss.

  Therefore, in the above configuration, a response time that is a time required for the discharge pressure sensor value to converge to the target discharge pressure from the time when the prescribed condition is satisfied is acquired, and it is estimated that the oil viscosity is lower as the response time is shorter. Like to do. Thus, by estimating the oil viscosity based on the response time that is less affected by changes in pressure loss upstream than the sensor in the discharge oil passage, the pressure loss upstream of the sensor in the discharge oil passage can be reduced. The viscosity of the oil can be estimated in a manner in which the influence due to the change is suppressed.

  It should be noted that the difference in the response time acquired when the oil viscosity is high and low as the difference between the target discharge pressure and the discharge pressure sensor value is large and the oil viscosity is high and low, as the change amount per unit time of the target discharge pressure is large. It is easy to come out. Therefore, when the amount of change in the target discharge pressure per unit time is equal to or greater than the target change determination value, the response time is measured as the prescribed condition is satisfied, and the oil viscosity is estimated using the response time. The estimation accuracy of the viscosity can be increased.

  As an oil pump, an engine-driven oil pump that has an input shaft that rotates in synchronization with the rotation of the crankshaft of the engine and that can operate the oil discharge amount per rotation of the input shaft is employed. There may be. In this case, the higher the engine speed, the higher the oil discharge amount per rotation of the input shaft, and the higher the oil discharge pressure in the oil pump. That is, when the change amount per unit time of the engine rotation speed is large under the condition where the target discharge pressure is not changed, the difference between the target discharge pressure and the discharge pressure sensor value becomes large. And the difference of the said response time acquired by the case where the viscosity of oil is high and the case where it is low becomes so easy that the said difference is large in this way. Therefore, when the oil pump is an engine-driven oil pump, the response time is measured assuming that the specified condition is satisfied when the amount of change in the engine rotation speed per unit time is equal to or greater than the rotation change determination value, and the response time By estimating the viscosity of the oil using the oil, it is possible to increase the estimation accuracy of the viscosity of the oil.

  If unburned fuel in the engine is mixed with oil, the oil is diluted and the viscosity of the oil is lowered. When the amount of unburned fuel mixed with the oil increases and the dilution of the oil proceeds, the viscosity of the oil becomes extremely low, so that the response time becomes extremely short. Therefore, it is preferable that the processing unit performs a notification process that prompts oil change on the condition that the response time acquired by the response time acquisition unit is less than the notification determination time. According to this configuration, when it can be determined that the response time is extremely short based on the fact that the response time is less than the notification determination time, it is possible to notify the user of oil replacement.

  Further, the processing unit controls the operation of the oil pump to converge the discharge pressure sensor value to the target discharge pressure on the condition that the response time acquired by the response time acquisition unit is equal to or longer than the notification determination time. The parameter may be equal to a value corresponding to the viscosity of the oil estimated from the response time.

  Even if the response time is equal to or longer than the notification determination time, the oil is diluted to such an extent that it is not necessary to change the oil, and the viscosity of the oil may be lower than when the oil is not diluted. Therefore, in the above configuration, the parameter for controlling the operation of the oil pump is made equal to a value corresponding to the oil viscosity estimated from the response time. Therefore, even if the viscosity of the oil discharged from the oil pump becomes low, the operation control of the oil pump according to the current viscosity of the oil can be performed.

  By the way, the oil used in the oil supply apparatus may be replaced with a kind of oil having a lower viscosity than before. Even in this case, in order to properly control the operation of the oil pump, the type of oil discharged from the oil pump is appropriately estimated, and the parameters for controlling the operation of the oil pump are estimated. It will be a value according to the type of oil.

  Therefore, on the condition that the response time acquired by the response time acquisition unit is less than the determination time for determination, the processing unit has a kind of oil whose viscosity is lower than that when the response time is equal to or greater than the determination time for determination. Estimate that the oil is being discharged from the oil pump, and change the parameter for controlling the operation of the oil pump so that the discharge pressure sensor value converges to the target discharge pressure to a value corresponding to the low-viscosity oil. May be. According to this configuration, when the response time is less than the determination determination time, the parameter is set to a value corresponding to a type of oil having a lower viscosity than when the response time is equal to or greater than the determination determination time. Can do. Therefore, even when a low-viscosity type oil is used, the operation control of the oil pump according to the type of the oil can be performed.

The schematic diagram which shows the function structure of the control apparatus which is 1st Embodiment of an oil viscosity estimation apparatus, and the outline of the oil circulation path | route in an engine provided with the control apparatus. FIG. 3 is a cross-sectional view showing an oil pump whose operation is controlled by the control device, and showing a state in which the oil discharge pressure is maximum. It is sectional drawing which shows the oil pump, Comprising: The figure which shows the state in which the discharge pressure of oil is the minimum. The flowchart explaining the processing routine which the response time acquisition part of the control apparatus performs. The flowchart explaining the process routine which the process part of the same control apparatus performs. The timing chart which shows transition of the discharge pressure of the oil in an oil pump when it transfers to a non-steady state from a steady state. The flowchart explaining the process routine which the process part of the control apparatus which is 2nd Embodiment of an oil viscosity estimation apparatus performs.

Hereinafter, a first embodiment of an oil viscosity estimating apparatus will be described with reference to FIGS.
FIG. 1 illustrates an oil circulation path in an engine 200 including a control device 300 that is an oil viscosity estimation device of the present embodiment. As shown in FIG. 1, the engine 200 includes an oil pan 201 that stores oil, and a main oil gallery 202 to which oil in the oil pan 201 is supplied via an oil supply device 210. The engine 200 is provided with a plurality of devices 203 that require oil supply. Then, the oil discharged from the device 203 returns to the oil pan 201.

  The oil supply device 210 includes an oil pump 10 that can change the oil discharge pressure and an oil control valve 100. The control device 300 controls the drive of the oil control valve 100 so that the oil discharge pressure in the oil pump 10 is changed.

Next, the oil pump 10 will be described with reference to FIGS. 1, 2, and 3.
The oil pump 10 is a variable displacement pump that is driven based on the rotation of the crankshaft of the engine 200. As shown in FIGS. 2 and 3, the oil pump 10 includes an input shaft 11 that rotates in synchronization with the crankshaft, and a casing member CS in which a housing space 40 is partitioned. The housing space 40 is provided with an inner rotor 50 that rotates integrally with the input shaft 11, an outer rotor 60 that is disposed on the outer peripheral side of the inner rotor 50, and a ring-shaped adjustment ring 70 that surrounds the outer rotor 60.

  The casing member CS is provided with a suction port 12 for sucking oil therein and a discharge port 13 for discharging the oil inside the casing member CS. As shown in FIG. 1, the suction port 12 communicates with a suction oil passage 114 that leads to an oil pan 201, and the discharge port 13 communicates with a discharge oil passage 13 a that leads to a main oil gallery 202. The discharge oil passage 13a is provided with a filter 13b for capturing foreign matter discharged from the discharge port 13 together with oil.

  As shown in FIGS. 2 and 3, a plurality of external teeth 51 are provided on the outer periphery of the inner rotor 50, and a plurality of internal teeth 61 that mesh with the outer teeth 51 of the inner rotor 50 are provided on the inner periphery of the outer rotor 60. It has been. The number of inner teeth 61 is one more than the number of outer teeth 51. The outer rotor 60 is rotatably held by the adjustment ring 70.

  The rotation center of the outer rotor 60 is eccentric with respect to the rotation center of the inner rotor 50. The outer teeth 51 of the inner rotor 50 and the inner teeth 61 of the outer rotor 60 are in a state in which a part thereof (the right side portion in FIG. 2) is engaged with each other. A working chamber 41 filled with oil is formed between the outer periphery of the inner rotor 50 and the inner periphery of the outer rotor 60.

  In the working chamber 41, in a portion from a position where the outer teeth 51 of the inner rotor 50 and the inner teeth 61 of the outer rotor 60 are engaged with each other to a predetermined position in the rotation direction of the input shaft 11 indicated by an arrow in FIG. The clearance between the outer teeth 51 of the inner rotor 50 and the inner teeth 61 of the outer rotor 60 gradually increases with the rotation. The portion where the gap between the outer teeth 51 of the inner rotor 50 and the inner teeth 61 of the outer rotor 60 gradually increases in this way communicates with the suction port 12. On the other hand, in the working chamber 41, a portion where the gap between the outer teeth 51 of the inner rotor 50 and the inner teeth 61 of the outer rotor 60 gradually decreases as the rotors 50 and 60 rotate is in communication with the discharge port 13.

  When the oil pump 10 is driven, the input shaft 11 rotates to rotate the rotors 50 and 60 while meshing with each other. Then, the oil stored in the oil pan 201 is sucked into the working chamber 41 from the suction port 12 through the suction oil passage 114 and discharged from the discharge port 13 to the discharge oil passage 13a.

  The adjustment ring 70 includes a ring-shaped main body 71 that holds the outer rotor 60, and a protrusion 72 that protrudes from the outer periphery of the main body 71 in the radial direction of the rotors 50 and 60. The main body 71 of the adjustment ring 70 is provided with elongated holes 711 and 712 extending in the specified direction. Guide pins 81 and 82 fixed to the casing member CS are inserted through the long holes 711 and 712. Thereby, the adjustment ring 70 can be displaced in the extending direction of the long holes 711 and 712.

  A first seal member 83 is provided at the tip of the protrusion 72 of the adjustment ring 70, and a second seal member 84 is provided in the main body 71. The seal members 83 and 84 abut against the side wall of the casing member CS, and the space between the side wall and the outer periphery of the adjustment ring 70 is sealed, whereby the adjustment ring 70 and the seal members 83, A control oil chamber 42 is defined by 84.

  The control oil chamber 42 is provided with an opening 14 communicating with the control oil passage 111, and oil can be supplied from the oil control valve 100 to the control oil chamber 42 through the control oil passage 111 and the opening 14. Yes. In addition, the accommodation space 40 is provided with a spring 15 that applies an urging force to the projecting portion 72 in a direction to reduce the volume of the control oil chamber 42. The spring 15 is disposed on the opposite side of the control oil chamber 42 with the protrusion 72 interposed therebetween. FIG. 2 shows a state where the adjustment ring 70 is held at a position where the volume of the control oil chamber 42 is minimized by the biasing force from the spring 15 because the internal pressure of the control oil chamber 42 is low. In the present embodiment, the position of the adjustment ring 70 when the volume of the control oil chamber 42 is minimized, that is, the position of the adjustment ring 70 in FIG. 2 is referred to as an “initial position”.

  When the adjustment ring 70 is disposed at the initial position, when oil is supplied to the control oil chamber 42 and the internal pressure of the control oil chamber 42 increases, the control oil chamber resists the urging force from the spring 15. The adjustment ring 70 is displaced from the initial position in the direction of increasing the volume of 42. That is, the adjustment ring 70 is displaced while rotating in the direction from the state shown in FIG. 2 toward the state shown in FIG. 3 (counterclockwise direction in FIG. 2). On the other hand, when the oil is discharged from the control oil chamber 42 by driving the oil control valve 100, the internal pressure of the control oil chamber 42 is lowered, and the volume of the control oil chamber 42 is reduced by the urging force from the spring 15. The adjustment ring 70 is displaced in the direction. That is, the adjustment ring 70 is displaced while rotating in the direction (clockwise direction in FIG. 3) from the state shown in FIG. 3 toward the state shown in FIG. That is, the position of the adjustment ring 70 is determined by the internal pressure of the control oil chamber 42 and the urging force from the spring 15. As the position of the adjustment ring 70 changes, the relative positions of the meshed portions of the teeth 51 and 61 of the inner rotor 50 and the outer rotor 60 with respect to the openings of the suction port 12 and the discharge port 13 change. For this reason, the amount of oil discharged from the discharge port 13 per rotation of the input shaft 11, that is, the pressure of oil discharged from the discharge port 13, by changing the position of the adjustment ring 70 by adjusting the internal pressure of the control oil chamber 42. The discharge pressure is changed.

  Specifically, in the oil pump 10, when the position of the adjustment ring 70 is in the “initial position” as shown in FIG. 2, the oil discharge pressure becomes maximum. As shown in FIG. 2, when the internal pressure of the control oil chamber 42 increases from a state where the oil discharge pressure is at the maximum, the adjustment ring 70 resists the urging force from the spring 15 as the internal pressure increases. It is displaced while rotating counterclockwise in FIG. As a result, in the portion where the gap between the external teeth 51 and the internal teeth 61 gradually increases with the rotation of the rotors 50 and 60, the range overlapping the suction port 12 becomes small, and the external teeth 51 and the internal teeth A part of the portion where the gap with 61 gradually decreases overlaps with the suction port 12. As a result, the oil discharge pressure is lowered. On the contrary, when the internal pressure of the control oil chamber 42 becomes low, the adjustment ring 70 is displaced while being rotated in the clockwise direction in FIG. Get higher.

Next, the oil control valve 100 will be described with reference to FIGS. 1, 2, and 3.
As shown in FIGS. 1 and 2, the oil control valve 100 can switch the communication state of a plurality of oil paths by switching the position of the spool by driving an electromagnetically driven actuator 100A. That is, the oil control valve 100 discharges oil from the control port 101 to which the control oil passage 111 is connected, the supply port 102 to which the supply oil passage 112 branched from the discharge oil passage 13a of the oil pump 10 is connected, and oil. And a discharge port 103 to which the discharge oil passage 113 is connected. Then, by adjusting the instruction current value Iocv for the actuator 100A, the position of the spool is a discharge position (FIG. 2) for discharging the oil recirculated to the control port 101 from the discharge port 103, and the oil supplied to the supply port 102 Between the control port 101 and the supply position (FIG. 3). In other words, in the present embodiment, as the command current value Iocv input to the actuator 100A increases, the spool is displaced from the discharge position toward the supply position. Thus, by displacing the spool from the discharge position toward the supply position, the internal pressure of the control oil chamber 42 of the oil pump 10 can be increased, that is, the oil discharge pressure in the oil pump 10 can be decreased. .

Next, the control device 300 will be described with reference to FIG.
As shown in FIG. 1, a discharge pressure sensor 311, a temperature sensor 312, and a crank angle sensor 313 are electrically connected to the control device 300. The discharge pressure sensor 311 is disposed downstream of the filter 13b in the discharge oil passage 13a, and detects a discharge pressure sensor value PS that is the pressure of oil that has passed through the filter 13b. The temperature sensor 312 detects an oil temperature TMP that is the temperature of oil supplied to the oil pump 10, and the crank angle sensor 313 detects an engine rotation speed NE that is the rotation speed of the crankshaft of the engine 200. The control device 300 controls the operation of the oil supply device 210 based on information detected by the sensors 311 to 313.

  The control device 300 also functions as a target pressure setting unit 301, a discharge pressure control unit 302, and a response time acquisition unit as functional units for controlling the oil discharge pressure in the oil pump 10 and estimating the oil viscosity. 303 and a processing unit 304.

  The target pressure setting unit 301 derives a target discharge pressure PTr that is a target value of the oil discharge pressure in the oil pump 10. Then, the target pressure setting unit 301 outputs the derived target discharge pressure PTr to the discharge pressure control unit 302 and the response time acquisition unit 303.

  The discharge pressure control unit 302 calculates an instruction current value Iocv based on feedback control using the target discharge pressure PTr and the discharge pressure sensor value PS input from the target pressure setting unit 301, and uses the instruction current value Iocv as an actuator. By inputting to 100A, the internal pressure of the control oil chamber 42, that is, the oil discharge pressure in the oil pump 10 is controlled. Specifically, the discharge pressure control unit 302 calculates an instruction target discharge pressure PTrA using the following relational expression (formula 1), and obtains an instruction current value Iocv corresponding to the instruction target discharge pressure PTrA. . That is, the command current value Iocv increases as the command target discharge pressure PTrA decreases. In the relational expression (Expression 1), “X” is a proportional term for feedback control, and “Y” is an integral term for feedback control. “G” is a common gain, and the gain G is set to a value corresponding to the viscosity of the oil.

PTrA = (PTr + X + Y) × G (Formula 1)
The response time acquisition unit 303 acquires a response time TM that is a time required for the discharge pressure sensor value PS to converge to the target discharge pressure PTr from the time when the specified condition is satisfied. The specified condition is a condition for determining that the discharge pressure sensor value PS is smaller than the target discharge pressure PTr, and details thereof will be described later. Then, the response time acquisition unit 303 outputs the acquired response time TM to the processing unit 304.

  The processing unit 304 estimates the oil viscosity based on the response time TM input from the response time acquisition unit 303, and performs processing according to the estimation result. Specifically, when the viscosity of the oil estimated from the response time TM is extremely low, the processing unit 304 has a large amount of unburned fuel mixed into the oil, and the dilution of the oil proceeds so that the oil needs to be replaced. It judges that it is carrying out, and performs the alerting | reporting process which urges oil replacement. Further, when the processing unit 304 does not determine that the oil dilution has progressed to the extent that oil replacement is necessary, the processing unit 304 is based on the estimated value of the oil viscosity used in the oil supply device 210. The gain G, which is a parameter for controlling the operation of, is corrected.

  Next, a processing routine executed by the response time acquisition unit 303 to acquire the response time TM will be described with reference to FIG. This processing routine is executed when a transition is made from a steady state where the discharge pressure sensor value PS converges to the target discharge pressure PTr to an unsteady state where the discharge pressure sensor value PS does not converge to the target discharge pressure PTr.

  As shown in FIG. 4, in the present processing routine, the response time acquisition unit 303 determines whether the specified condition is satisfied (step S11). In the present embodiment, the specified condition is that the increase amount IPTr per unit time of the target discharge pressure PTr is equal to or greater than the increase amount determination value IPTrTh, and the decrease amount DNE per unit time of the engine rotation speed NE is the decrease amount determination value. It is a logical sum of DNETh or more. The “unit time” here is equal to the length of time of the execution cycle of the feedback control. The increase amount determination value IPTrTh is an example of a “target change determination value”. When the increase amount IPTr is equal to or greater than the increase amount determination value IPTrTh, the target discharge pressure PTr is changed and the discharge pressure sensor value PS The value is set such that it can be determined that the difference from the target discharge pressure PTr has increased. Further, the decrease amount determination value DNETh is an example of a “rotation change determination value”. When the decrease amount DNE is equal to or greater than the decrease amount determination value DNETh, the engine speed NE is decreased, so the discharge pressure sensor value PS and the target The value is set such that it can be determined that the difference from the discharge pressure PTr has increased.

  When the specified condition is satisfied, it is determined that the target discharge pressure PTr is different from the discharge pressure sensor value PS. On the other hand, when the specified condition is not satisfied, it is not determined that the target discharge pressure PTr is different from the discharge pressure sensor value PS even if the steady state is shifted to the unsteady state.

  Therefore, when the specified condition is satisfied (step S11: YES), the response time acquisition unit 303 starts measuring the response time TM (step S12). Then, the response time acquisition unit 303 determines whether or not the discharge pressure sensor value PS has converged to the target discharge pressure PTr (step S13). When it has not converged yet (step S13: NO), the response time acquisition unit 303 repeats the determination process of step S13 until the discharge pressure sensor value PS converges to the target discharge pressure PTr. On the other hand, when it has already converged (step S13: YES), the response time acquisition unit 303 ends the measurement of the response time TM (step S14), and ends this processing routine.

  On the other hand, if the prescribed condition is not satisfied in step S11 (NO), the response time acquisition unit 303 ends this processing routine. That is, when the prescribed condition is not satisfied, that is, when the difference between the discharge pressure sensor value PS and the target discharge pressure PTr is small even after shifting from the steady state to the unsteady state, the response time TM is not acquired.

Next, a processing routine executed by the processing unit 304 when the response time TM is acquired by the response time acquisition unit 303 will be described with reference to FIG.
As shown in FIG. 5, in this processing routine, the processing unit 304 determines whether or not the response time TM input from the response time acquisition unit 303 is less than the notification determination time TMTh1 (step S21).

  When the oil is diluted by mixing unburned fuel into the oil, the viscosity of the oil is lowered and the response time TM is shortened. For this reason, when the amount of unburned fuel mixed in the oil increases and the dilution of the oil proceeds, the viscosity of the oil becomes extremely low, and the response time TM becomes extremely short. When the oil is diluted as described above and the viscosity of the oil becomes extremely low, it is necessary to change the oil. Therefore, in this embodiment, the notification determination time TMTh1 is set as a determination value for determining whether or not the viscosity of the oil has become extremely low due to the progress of oil dilution. Then, when the response time TM is less than the notification determination time TMTh1, it is determined that there is a possibility that oil dilution has progressed to the extent that oil replacement is necessary. On the other hand, when the response time TM is equal to or longer than the notification determination time TMTh1, it is determined that the oil dilution has not progressed to the extent that oil replacement is necessary.

  Therefore, when the response time TM is less than the notification determination time TMTh1 (step S21: YES), the processing unit 304 increments the notification determination counter CNT1 by “1” (step S22). This notification determination counter CNT1 is the number of consecutive times that the response time TM becomes less than the notification determination time TMTh1. Then, the processing unit 304 determines whether or not the updated notification determination counter CNT1 is greater than or equal to the notification start determination value CNTTh1 (step S23). The notification start determination value CNTTh1 is set to an integer equal to or greater than “2” (for example, 4). When the notification determination counter CNT1 becomes equal to or greater than the notification start determination value CNTTh1, it is determined that oil dilution has progressed to the extent that oil replacement is necessary.

  Therefore, when the notification determination counter CNT1 is greater than or equal to the notification start determination value CNTTh1 (step S23: YES), the processing unit 304 performs a notification process that prompts oil replacement (step S24). That is, in this embodiment, the notification process is performed on condition that the response time TM is less than the notification determination time TMTh1. Thereafter, the processing unit 304 ends this processing routine. On the other hand, when the notification determination counter CNT1 is less than the notification start determination value CNTTh1 (step S23: NO), the processing unit 304 ends this processing routine without performing the notification processing.

  On the other hand, when the response time TM is equal to or longer than the notification determination time TMTh1 in step S21 (NO), the processing unit 304 resets the notification determination counter CNT1 to “0” (step S25). And the process part 304 performs the estimation process which estimates the viscosity of the oil currently used with the oil supply apparatus 210 (step S26). That is, in this estimation process, the processing unit 304 estimates that the oil viscosity is lower as the response time TM is shorter. Subsequently, the processing unit 304 performs correction processing of a control parameter used for controlling the oil discharge pressure in the oil pump 10 based on the estimated oil viscosity (step S27). For example, in the correction process, the processing unit 304 corrects the gain G of the relational expression (Expression 1), which is an example of a feedback control parameter, according to the estimated oil viscosity. Thereafter, the processing unit 304 ends this processing routine.

  Next, referring to FIG. 6, an explanation will be given of the operation when the prescribed condition is satisfied when the steady state is shifted to the unsteady state, together with the effects. In FIG. 6, the broken line represents the change in the discharge pressure sensor value PS when unburned fuel is not mixed in the oil, while the thick solid line represents unburned fuel mixed in the oil. It shows the transition of the discharge pressure sensor value PS when the dilution of oil is progressing to the extent that replacement is necessary.

  When foreign matter is captured by the filter 13b disposed in the discharge oil passage 13a, the pressure loss becomes larger on the upstream side than the discharge pressure sensor 311 in the discharge oil passage 13a. In this case, in the discharge oil passage 13a, a differential pressure corresponding to the magnitude of the pressure loss is generated between the upstream side of the filter 13b and the downstream side of the filter 13b. When the oil discharge pressure in the oil pump 10 is increased under such a situation where the differential pressure is generated, the hydraulic pressure upstream of the filter 13b in the discharge oil passage 13a is maintained in such a manner that the differential pressure is maintained. In addition, both the hydraulic pressures downstream of the filter 13b become higher. Therefore, the increasing speed of the discharge pressure sensor value PS when increasing the discharge pressure sensor value PS toward the target discharge pressure PTr is not easily influenced by the pressure loss. Accordingly, the lower the oil viscosity, the shorter the time required for the discharge pressure sensor value SP to converge to the target discharge pressure PTr. That is, the length of the response time TM is not easily influenced by the pressure loss.

  In the present embodiment, when the specified condition is satisfied when the steady state is changed to the unsteady state, the response is a time from when the specified condition is satisfied until the discharge pressure sensor value PS converges to the target discharge pressure PTr. Time TM is acquired. And it is estimated that the viscosity of the oil currently used with the oil supply apparatus 210 is so low that this response time TM is short. Thus, by estimating the oil viscosity based on the response time TM that is less influenced by the change in pressure loss upstream of the discharge pressure sensor 311 in the discharge oil passage 13a, the influence due to the change in pressure loss is suppressed. In an embodiment, the viscosity of the oil can be estimated.

  Further, in the present embodiment, when the transition from the steady state to the unsteady state is performed, the difference between the discharge pressure sensor value PS and the target discharge pressure PTr is acquired as the oil viscosity is high or low. Difference in response time TM is likely to occur. Therefore, when the transition from the steady state to the unsteady state is performed, the increase amount IPTr per unit time of the target discharge pressure PTr is equal to or greater than the increase amount determination value IPTrTh, and the decrease amount per unit time of the engine speed NE. The response time TM is acquired only when at least one condition that DNE is equal to or greater than the decrease amount determination value DNETh is satisfied and the specified condition is satisfied. And by estimating the oil viscosity using the response time TM acquired at such time, the viscosity of the oil can be estimated with high accuracy.

  For example, as shown in FIG. 6, the target discharge pressure PTr increases at the first timing t11. If the increase amount IPTr per unit time of the target discharge pressure PTr is larger than the increase amount determination value IPTrTh, the specified condition is satisfied. At this time, if the oil is not diluted, the discharge pressure sensor value PS converges to the target discharge pressure PTr at the fourth timing t14 as shown by a broken line in FIG. 6 and shifts from the unsteady state to the steady state. . The fourth timing t14 is a timing after the third timing t13 when the notification determination time TMTh1 has elapsed from the first timing t11. Therefore, the notification determination counter CNT1 remains “0”.

  Under the condition that the oil temperature TMP is the same temperature, the amount of unburned fuel mixed with the oil gradually increases, and the viscosity of the oil gradually decreases as the dilution of the oil proceeds. Therefore, as the oil dilution progresses, the response time TM acquired when the specified condition is satisfied and the discharge pressure sensor value PS converges to the target discharge pressure PTr gradually decreases.

  When the response time TM acquired in this way is shortened, it can be estimated that the viscosity of the oil has decreased, and therefore the feedback control parameter is corrected by the estimated value of the viscosity of the oil based on the response time TM. Therefore, even if the oil viscosity becomes low due to the dilution of the oil, the operation of the oil pump 10 can be controlled according to the current oil viscosity.

  And when the amount of unburned fuel mixed into the oil increases and the dilution of the oil further proceeds, the response time TM acquired when the prescribed condition is satisfied becomes extremely short. When the discharge pressure sensor value PS converges to the target discharge pressure PTr at the second timing t12 prior to the third timing t13 as shown by a thick solid line in FIG. 6, the oil needs to be changed. Since it can be determined that there is a possibility that oil dilution is in progress, the notification determination counter CNT1 is updated. When the notification determination counter CNT1 becomes equal to or greater than the notification start determination value CNTTh1, oil replacement is prompted by notification processing. That is, when oil dilution has progressed to such an extent that oil replacement is necessary, oil replacement can be promoted.

(Second Embodiment)
Next, a second embodiment of the oil viscosity estimating apparatus will be described with reference to FIG. The second embodiment is different from the first embodiment in that the estimated value of the oil viscosity obtained based on the response time TM is used to estimate the type of oil. Therefore, in the following description, parts different from those of the first embodiment will be mainly described, and the same or corresponding member configurations as those of the first embodiment are denoted by the same reference numerals, and redundant description will be given. Shall be omitted.

Next, a processing routine executed by the processing unit 304 when the response time TM is acquired by the response time acquisition unit 303 will be described with reference to FIG.
As shown in FIG. 7, in the present processing routine, the processing unit 304 determines whether or not the response time TM input from the response time acquisition unit 303 is less than the determination time TMTh2 (step S31).

  In a situation where a low viscosity type oil is used in the oil supply device 210, when the oil discharge pressure in the oil pump 10 is increased, a high viscosity type oil is used in the oil supply device 210. The increase rate of the discharge pressure sensor value PS is higher than that. Therefore, the time required for the discharge pressure sensor value PS to converge to the target discharge pressure PTr from the point of transition from the steady state to the unsteady state, that is, the response time TM, is greater as the type of oil with lower viscosity is used. Shorter. In other words, the type of oil used in the oil supply device 210 can be estimated based on the response time TM.

  Therefore, in the present embodiment, the determination time TMTh2 is set as the determination time according to the responsiveness of the genuine oil used in the oil supply device 210. The viscosity of the oil decreases as the oil temperature TMP increases. Therefore, in the present embodiment, the determination time TMTh2 is made shorter as the oil temperature TMP is higher. When the response time TM input from the response time acquisition unit 303 is less than the determination time TMTh2, there is a possibility that a kind of oil having a viscosity lower than that of a genuine product may be used in the oil supply device 210. judge. On the other hand, when the response time TM is equal to or greater than the determination time TMTh2, it is not determined that there is a possibility that a kind of oil having a viscosity lower than that of a genuine product is used in the oil supply device 210.

  Therefore, when the response time TM is equal to or greater than the determination time TMTh2 (step S31: NO), the processing unit 304 resets an oil type estimation counter CNT2 described later to “0” (step S32). Thereafter, the processing unit 304 ends this processing routine. On the other hand, when the response time TM is less than the determination time TMTh2 (step S31: YES), the processing unit 304 increments the oil type estimation counter CNT2 by “1” (step S33). The oil type estimation counter CNT2 is the number of consecutive times that the response time TM becomes less than the determination time TMTh2.

  Then, the processing unit 304 determines whether or not the updated oil type estimation counter CNT2 is greater than or equal to the oil type estimation start determination value CNTTh2 (step S34). The oil type estimation start determination value CNTTh2 is set to an integer greater than or equal to “2” (for example, 4). When the oil type estimation counter CNT2 is equal to or greater than the oil type estimation start determination value CNTTh2, it is determined that a type of oil having a viscosity lower than that of a genuine product is used in the oil supply device 210. On the other hand, when the oil type estimation counter CNT2 is less than the oil type estimation start determination value CNTTh2, it is not determined that the oil supply device 210 uses a type of oil having a viscosity lower than that of the genuine product.

  Therefore, when the oil type estimation counter CNT2 is less than the oil type estimation start determination value CNTTh2 (step S34: NO), the processing unit 304 ends this processing routine. On the other hand, when the oil type estimation counter CNT2 is greater than or equal to the oil type estimation start determination value CNTTh2 (step S34: YES), the processing unit 304 performs an oil type estimation process (step S35). That is, in the oil type estimation process, the processing unit 304 estimates the oil type using the oil temperature TMP detected by the temperature sensor 312 in addition to the response time TM. For example, the processing unit 304 decreases the estimated value of the oil viscosity as the response time TM is shorter. At this time, the processing unit 304 corrects the estimated value of the oil viscosity calculated based on the response time TM using the oil temperature TMP so that the estimated value of the oil viscosity becomes higher as the oil temperature TMP is higher. Then, the processing unit 304 estimates the type of oil used in the oil supply device 210 based on the estimated value of the corrected oil viscosity. That is, the processing unit 304 has a map that associates the oil viscosity with the oil type, and derives the oil type corresponding to the estimated value of the oil viscosity using the map.

  Subsequently, the processing unit 304 performs a correction process for a control parameter used for controlling the oil discharge pressure in the oil pump 10 based on the estimated type of oil (step S36). For example, in the correction process, the processing unit 304 corrects the gain G of the relational expression (Expression 1), which is an example of a feedback control parameter, according to the estimated type of oil. Thereafter, the processing unit 304 ends this processing routine.

Next, the operation in the case where a kind of oil having a viscosity lower than that of a genuine product is used in the oil supply device 210 will be described together with effects.
When the specified condition is satisfied when the steady state is changed to the unsteady state, a response time TM that is a time from when the specified condition is satisfied until the discharge pressure sensor value PS converges to the target discharge pressure PTr is acquired. The Since a kind of oil having a viscosity lower than that of the genuine product is used in the oil supply device 210, the acquired response time TM is shorter than that in the case where the genuine product is used in the oil supply device 210. At this time, if the response time TM is less than the determination time TMTh2, the oil type estimation counter CNT2 is updated.

  When the oil type estimation counter CNT2 becomes equal to or greater than the oil type estimation start determination value CNTTh2, the oil type estimation process is performed. Then, the feedback control parameters are corrected based on the result of the estimation process. Therefore, even when oil having a lower viscosity than that of a genuine product is used in the oil supply device 210, the operation of the oil pump 10 can be controlled according to the oil type.

In addition, you may change each said embodiment into another embodiment as follows.
When the discharge pressure sensor value PS is larger than the target discharge pressure PTr, the specified condition is satisfied, and from when it is determined that the specified condition is satisfied, until the discharge pressure sensor value PS converges to the target discharge pressure PTr. You may make it acquire time as response time TM. Even in this case, the response time TM becomes shorter as the oil viscosity is lower, and is less susceptible to the magnitude of the pressure loss upstream of the filter 13b in the discharge oil passage 13a. Therefore, by estimating the oil viscosity using the response time TM acquired in this way, even if the pressure loss increases on the upstream side of the filter 13b in the discharge oil passage 13a, the decrease in the estimation accuracy of the oil viscosity is suppressed. be able to.

  In this case, the specified conditions are, for example, that the decrease amount DPTr per unit time of the target discharge pressure PTr is equal to or greater than the decrease amount determination value DPTrTh, and the increase amount INE per unit time of the engine rotation speed NE is the increase amount determination value. What is necessary is just to be the logical sum of being more than INETh. In this case, the decrease amount determination value DPTrTh corresponds to the “target change determination value”, and the increase amount determination value INETh corresponds to the “rotation change determination value”.

  In the above embodiment, the oil supply device 210 includes a gear pump as the oil pump 10. However, the oil supply apparatus 210 may be configured to include another type of pump (for example, a vane pump) other than the gear pump as the oil pump 10.

  The oil pump may be an electric pump instead of an engine driven pump. In this case, the oil discharge pressure in the oil pump can be controlled by adjusting the rotation speed of the electric motor, that is, the instruction current value for the electric motor. In the oil supply apparatus including such an electric oil pump, the specified condition may be satisfied when the target discharge pressure PTr decreases or increases. Even in such an oil supply device, the oil viscosity can be accurately estimated by using the response time TM that is the time from when the prescribed condition is satisfied until the discharge pressure sensor value PS converges to the target discharge pressure PTr.

  In the oil supply device including such an electric oil pump, the rotation speed of the electric motor is not synchronized with the engine rotation speed NE. Therefore, even if the engine rotational speed NE increases, the prescribed condition is not satisfied unless the rotational speed of the electric motor changes.

DESCRIPTION OF SYMBOLS 10 ... Oil pump, 11 ... Input shaft, 13a ... Discharge oil path, 200 ... Engine, 210 ... Oil supply apparatus, 300 ... Control apparatus, 303 ... Response time acquisition part, 304 ... Processing part, 311 ... Discharge pressure sensor.

Claims (6)

An oil pump capable of changing an oil discharge pressure, a discharge oil passage through which oil discharged from the oil pump flows, and a sensor that detects a pressure of oil flowing through the discharge oil passage, and discharge to the oil pump Applied to an oil supply device in which the operation of the oil pump is controlled so that a discharge pressure sensor value that is the pressure of oil detected by the sensor converges to a target discharge pressure that is a target value of pressure,
A response time for obtaining a response time that is a time required for the discharge pressure sensor value to converge to the target discharge pressure from a point in time when a prescribed condition that can determine that the target discharge pressure is different from the discharge pressure sensor value is satisfied An acquisition unit;
And a processing unit that estimates that the viscosity of the oil is lower as the acquired response time is shorter. The oil viscosity estimation apparatus according to claim 1, wherein the specified condition includes that a change amount per unit time of the target discharge pressure is equal to or greater than a target change determination value. The oil pump has an input shaft that rotates in synchronization with the rotation of the crankshaft of the engine, and is a pump capable of operating an oil discharge amount per one rotation of the input shaft,
The oil viscosity estimation apparatus according to claim 1, wherein the prescribed condition includes that a change amount per unit time of the engine rotation speed is equal to or greater than a rotation change determination value. The said process part performs the alerting | reporting process which urges oil change on the condition that the said response time acquired by the said response time acquisition part is less than the determination time for alerting | reporting. The oil viscosity estimation apparatus according to item. The processing unit operates the oil pump to converge the discharge pressure sensor value to the target discharge pressure on the condition that the response time acquired by the response time acquisition unit is equal to or longer than the notification determination time. The oil viscosity estimation device according to claim 4, wherein a parameter for controlling the pressure is made equal to a value corresponding to the viscosity of the oil estimated from the response time. The processing unit is of a type having a lower viscosity than the case where the response time is equal to or greater than the determination time for determination on condition that the response time acquired by the response time acquisition unit is less than the determination time for determination. Estimated that oil is being discharged from the oil pump, and the parameter for controlling the operation of the oil pump to converge the discharge pressure sensor value to the target discharge pressure is a value corresponding to a low viscosity type oil The oil viscosity estimation apparatus according to any one of claims 1 to 3.

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