Lubricating oil dilution suppressing device

Abstract

To provide a lubricating oil dilution suppressing device capable of suppressing the increase of a dilution ratio of lubricating oil.SOLUTION: A lubricating oil dilution suppressing device 1 includes a tank 2, a gas discharge passage 3, an oil introduction passage 4, a gas introduction passage 5, an oil discharge passage 6, a solenoid valve 7, and a control unit 8. The tank 2 is arranged outside or inside a crankcase CC of an internal combustion engine ICE. The gas discharge passage 3 discharges gas from the inside of the tank 2 to the outside of the tank 2, and the oil introduction passage 4 introduces lubricating oil LO from an oil pan OP of the internal combustion engine ICE into the inside of the tank 2. The gas introduction passage 5 introduces gas from the outside of the tank 2 into the inside of the tank 2, and the oil discharge passage 6 discharges the lubricating oil LO from the tank 2 to the oil pan OP. The solenoid valves 7 are provided in the gas outlet passage 3, the oil introduction passage 4, the gas introduction passage 5, and the oil introduction passage 6, respectively, and the control unit 8 controls the opening and closing of the solenoid valves 7 individually.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a lubricant dilution control device. [Background technology]

[0002] Conventionally, a control device for an internal combustion engine is known (for example, Patent Document 1 below). The control device for an internal combustion engine described in Patent Document 1 can prevent the temperature of the lubricating oil from increasing and the dilution rate of the lubricating oil from increasing by injecting the lubricating oil from an oil jet when the temperature of the lubricating oil falls within the operating oil temperature range. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-216266 Summary of the Invention [Problem to be solved by the invention]

[0004] The control device for an internal combustion engine described in Patent Document 1 above may not be able to sufficiently increase the temperature of the lubricating oil, for example, when the internal combustion engine is driven intermittently for short periods of time and cold starts are repeated, which may result in an increase in the dilution rate of the lubricating oil.

[0005] The present disclosure provides a lubricant dilution suppression device that can suppress an increase in the dilution rate of lubricant. [Means for solving the problem]

[0006] One aspect of the present disclosure provides a lubricating oil dilution suppression device comprising: a tank disposed inside or outside the crankcase of an internal combustion engine; a gas outlet passage for discharging gas from inside the tank to outside the tank; an oil inlet passage for introducing lubricating oil from an oil pan of the internal combustion engine to inside the tank; a gas inlet passage for introducing gas from outside the tank to inside the tank; an oil outlet passage for discharging the lubricating oil from the tank to the oil pan; solenoid valves provided in each of the gas outlet passage, the oil inlet passage, the gas inlet passage, and the oil outlet passage; and a control unit for individually controlling the opening and closing of the solenoid valves. [Effects of the Invention]

[0007] According to the above-described aspects of the present disclosure, it is possible to provide a lubricant dilution suppression device that can suppress an increase in the dilution rate of the lubricant. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram illustrating an embodiment of a lubricant oil dilution suppression device according to the present disclosure. [Figure 2] 2 is a flowchart showing the flow of processing by a control unit of the lubricant oil dilution suppression device of FIG. 1. [Figure 3] 3 is a graph illustrating a process for calculating the amount of mixed water and fuel shown in FIG. 2. [Figure 4] 2 is a timing chart showing the operation of each part of the lubricant oil dilution suppression device shown in FIG. [Figure 5] 2 is a flowchart showing the flow of processing by a control unit of the lubricant oil dilution suppression device of FIG. 1. [Figure 6] 2 is a flowchart showing the flow of processing by a control unit of the lubricant oil dilution suppression device of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the invention will be described with reference to the drawings.

[0010] 1 is a schematic diagram showing an embodiment of a lubricant dilution suppression device according to the present disclosure. The lubricant dilution suppression device 1 of this embodiment is mounted on a vehicle equipped with an internal combustion engine (ICE), such as an internal combustion engine vehicle, a battery electric vehicle (BEV) equipped with an internal combustion engine as a generator, a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV). Fuels used in the internal combustion engine (ICE) include, for example, conventional fuels such as gasoline, diesel, and LPG, as well as carbon-neutral fuels such as hydrogen, synthetic fuels, and biomass fuels.

[0011] The internal combustion engine ICE includes, for example, a cylinder head CH, a cylinder block CB, a crankcase CC, and an oil pan OP. The internal combustion engine ICE also includes, for example, an intake passage IP provided with an air cleaner AC and a throttle valve Vth, and an exhaust passage EP provided with a three-way catalyst TC. The three-way catalyst TC may be, for example, an electrically heated catalyst that can be heated by an electric heater EH.

[0012] The internal combustion engine ICE also has, for example, a bypass passage BP and a blow-by gas passage BGP. The bypass passage BP connects, for example, an intake passage IP upstream of the throttle valve Vth to the cylinder head CH. The blow-by gas passage BGP connects, for example, a crankcase CC to the intake manifold IM. The blow-by gas passage BGP is provided with, for example, a PCV valve Vpc.

[0013] The internal combustion engine ICE also includes, for example, an oil pump Po and a vacuum pump Pv. The oil pump Po is driven, for example, by rotation of a crankshaft CS connected to a piston PI via a connecting rod CR, and delivers lubricating oil LO stored in an oil pan OP to various components of the internal combustion engine ICE. The suction port of the vacuum pump Pv is connected, for example, to a negative pressure chamber of a brake booster that assists the braking operation of the vehicle driver. The discharge port of the vacuum pump Pv is connected, for example, to a blow-by gas passage BGP.

[0014] The internal combustion engine ICE also includes a lubricant dilution suppression device 1 that suppresses dilution of the lubricant LO with, for example, water or fuel. The lubricant dilution suppression device 1 includes, for example, a tank 2, a gas outlet path 3, an oil introduction path 4, a gas introduction path 5, an oil introduction path 6, a plurality of solenoid valves 7, and a control unit 8.

[0015] The tank 2 is disposed, for example, outside the crankcase CC of the internal combustion engine ICE. Alternatively, the tank 2 may be disposed inside the crankcase CC. The tank 2 is connected, for example, to the crankcase CC via a gas outlet passage 3 and to the oil pan OP via an oil introduction passage 4. The tank 2 is connected, for example, to the intake passage IP via a gas introduction passage 5 and to the oil pan OP via an oil introduction passage 6. The tank 2 is disposed, for example, vertically above the oil pan OP, and temporarily stores the lubricating oil LO introduced from the oil pan OP via the oil introduction passage 4.

[0016] The volume of the lubricating oil LO introduced into the tank 2 is smaller than the volume of the lubricating oil LO stored in the oil pan OP, for example. The volume of the lubricating oil LO introduced into the tank 2 is set within a range that does not interfere with the operation of the internal combustion engine ICE, for example, when the lubricating oil LO is introduced into the tank 2 from the oil pan OP.

[0017] The tank 2 includes, for example, a pressure sensor 21, a temperature sensor 22, and a heating device 23. The pressure sensor 21 detects, for example, the internal pressure of the tank 2 and outputs the detection result to the control unit 8. The temperature sensor 22 detects, for example, the temperature of the lubricating oil LO stored in the tank 2 and outputs the detection result to the control unit 8. The heating device 23 is, for example, an electric heater, and is controlled by the control unit 8 to heat the lubricating oil LO inside the tank 2.

[0018] The gas outlet path 3 is, for example, a passage for discharging gas from the inside of the tank 2 to the outside of the tank 2. In the flow direction Go of the gas passing through the gas outlet path 3, the upstream end of the gas outlet path 3 is connected, for example, to the upper part of the tank 2, and the downstream end of the tank 2 is connected, for example, to the crankcase CC. The downstream end of the gas outlet path 3 may be connected, for example, to the suction port of a vacuum pump Pv.

[0019] The oil introduction passage 4 is a passage that introduces the lubricating oil LO from, for example, an oil pan OP of the internal combustion engine ICE into the tank 2. In the flow direction Oi of the lubricating oil LO passing through the oil introduction passage 4, an upstream end of the oil introduction passage 4 is connected to, for example, the oil pan OP, and a downstream end of the oil introduction passage 4 is connected to, for example, the bottom of the tank 2.

[0020] The gas introduction path 5 is, for example, a path that introduces gas from the outside of the tank 2 into the inside of the tank 2. In the flow direction Gi of gas passing through the gas introduction path 5, an upstream end of the gas introduction path 5 is connected to the intake passage IP, for example, upstream of the throttle valve Vth, and a downstream end of the gas introduction path 5 is connected to the upper part of the tank 2, for example.

[0021] The oil discharge passage 6 is, for example, a passage that discharges the lubricating oil LO from the tank 2 to the oil pan OP. In the flow direction Oo of the lubricating oil LO passing through the oil discharge passage 6, the upstream end of the oil discharge passage 6 is connected to, for example, the bottom of the tank 2, and the downstream end of the oil discharge passage 6 is connected to, for example, the oil pan OP.

[0022] The solenoid valves 7 are provided, for example, in each of the gas discharge path 3, the oil introduction path 4, the gas introduction path 5, and the oil discharge path 6. Each solenoid valve 7 is individually opened and closed, for example, under the control of the control unit 8. The solenoid valves 7 include, for example, a gas discharge valve Vgo that opens and closes the gas discharge path 3, an oil introduction valve Voi that opens and closes the oil introduction path 4, a gas introduction valve Vgi that opens and closes the gas introduction path 5, and an oil discharge valve Voo that opens and closes the oil discharge path 6.

[0023] The control unit 8, for example, individually controls the opening and closing of the multiple solenoid valves 7. The control unit 8 is, for example, an electronic control unit (ECU) configured with one or more microcontrollers including a central processing unit (CPU) and memories such as RAM and ROM. The control unit 8 controls each part of the internal combustion engine ICE and the lubricant dilution suppression device 1, for example, by executing a program stored in the memory. The control unit 8 may, for example, also serve as an engine control unit that controls the internal combustion engine ICE, or may be provided separately from the engine control unit.

[0024] Fig. 2 is a flow diagram showing an example of the flow of processing by the control unit 8 of the lubricant dilution suppression device 1 of Fig. 1. For example, when a start switch of a vehicle equipped with an internal combustion engine ICE is turned on, the control unit 8 repeatedly executes the processing flow shown in Fig. 2 at a predetermined cycle until the start switch is turned off. When the processing flow shown in Fig. 2 starts, the control unit 8 executes, for example, processing S1 for calculating the amounts of water and fuel mixed into the lubricant oil LO.

[0025] Fig. 3 is a graph illustrating the process S1 for calculating the amounts of water and fuel mixed in shown in Fig. 2. In this process S1, the control unit 8 calculates the amount of water mixed in the lubricating oil LO, for example, by the following procedure.

[0026] The control unit 8, for example, refers to correlation data stored in advance in a memory. The correlation data is, for example, data that defines the correlation between the coolant temperature Tw of the internal combustion engine ICE, the load τ of the internal combustion engine ICE, the rotation speed N of the internal combustion engine ICE, and the mixing rate Rw of water into the lubricating oil LO, as shown in Fig. 3. The control unit 8 also acquires history data of the internal combustion engine ICE, for example, stored in a memory. The history data includes, for example, the history of the coolant temperature Tw of the internal combustion engine ICE, the history of the load τ of the internal combustion engine ICE, and the history of the rotation speed N of the internal combustion engine ICE.

[0027] The control unit 8 calculates the mixing rate Rw of water into the lubricating oil LO based on, for example, the correlation data and the history data. For example, as shown in Fig. 3, the mixing rate Rw2 of water into the lubricating oil LO when the cooling water temperature Tw, the load τ, and the rotation speed N are relatively low is lower than the mixing rate Rw1 of water into the lubricating oil LO when the cooling water temperature Tw, the load τ, and the rotation speed N are relatively high.

[0028] Furthermore, the control unit 8 calculates the amount of water mixed into the lubricating oil L0 based on the calculated water mixing rate Rw and its duration. Also, the control unit 8 calculates the amount of water mixed into the lubricating oil L0 up to the current process S1 by adding the amount of water mixed in newly calculated in the current process S1 and the amount of water mixed in calculated and accumulated in the previous process S1.

[0029] In addition, the control unit 8 calculates, for example, the amount of fuel mixed into the lubricating oil LO in the same manner as the amount of water mixed into the lubricating oil LO. After completing the process S1 for calculating the amounts of water and fuel mixed into the lubricating oil LO, the control unit 8 executes, for example, a process S2 for determining whether or not evaporation of the water or fuel mixed into the lubricating oil LO is required, as shown in FIG.

[0030] In this process S2, the control unit 8 determines whether the amounts of water and fuel mixed into the lubricating oil LO calculated in the previous process S1 exceed their respective thresholds. Here, if the control unit 8 determines that the amounts of water and fuel mixed into the lubricating oil LO do not exceed their respective thresholds (NO), for example, the control unit 8 ends the process flow shown in FIG.

[0031] Thereafter, the control unit 8 repeats the process flow shown in Fig. 2 at a predetermined cycle, for example, until the start switch of the vehicle is turned off. As a result, it is assumed that the control unit 8 determines in the above-mentioned process S2 that the amount of water mixed into the lubricating oil LO exceeds the threshold value, or that the amount of fuel mixed into the lubricating oil LO exceeds the threshold value (YES). In this case, the control unit 8 sequentially executes, for example, the oil introduction process S3, the negative pressure evaporation process S4, and the oil discharge process S5 shown in Fig. 2.

[0032] Fig. 4 is a timing diagram showing the operation of each part of the lubricant dilution suppression device 1 shown in Fig. 1. For example, as shown in the top graph of Fig. 4, at time t0 before the control unit 8 starts the oil introduction process S3, the liquid level OL of the lubricant LO stored inside the tank 2 is approximately at the lowest level (L).

[0033] As shown in the second graph from the top of Fig. 4, the internal pressure Pt of the tank 2 is, for example, approximately equal to atmospheric pressure (AP). As shown in the third graph from the top of Fig. 4, the vacuum pump Pv is, for example, turned on and operating. As shown in the fourth to bottom graphs from the top of Fig. 4, among the multiple solenoid valves 7, for example, the oil outlet valve Voo is in an open state (O), but the other valves, the oil introduction valve Voi, the gas introduction valve Vgi, and the gas introduction valve Vgo, are in a closed state (C).

[0034] Thereafter, when the control unit 8 starts the oil introduction process S3, it controls each solenoid valve 7 to open the gas outlet valve Vgo and the oil introduction valve Voi and close the gas introduction valve Vgi and the oil introduction valve Voo. As a result, for example, as shown in the bottom and fourth graphs from the bottom in Fig. 4, at time t1, the gas outlet valve Vgo and the oil introduction valve Voi transition from the closed state (C) to the open state (O). Also, as shown in the second graph from the bottom in Fig. 4, the gas introduction valve Vgi is maintained in the closed state (C), and as shown in the third graph from the bottom in Fig. 4, the oil introduction valve Voo transitions from the open state (O) to the closed state (C).

[0035] 1, the gas inside the tank 2 flows in a flow direction Go from the tank 2 toward the crankcase CC through the gas outlet passage 3 and the gas outlet valve Vgo in the open state (O). As a result, as shown in the second graph from the top in FIG. 4, the internal pressure Pt of the tank 2 decreases, and the lubricating oil LO stored in the oil pan OP flows in a flow direction Oi from the oil pan OP toward the tank 2 through the oil introduction passage 4 and the oil introduction valve Voi in the open state (O).

[0036] As a result, the lubricating oil LO is introduced from the oil pan OP into the tank 2, and the liquid level OL of the lubricating oil LO in the tank 2 rises as shown in the top graph of Fig. 4. Thereafter, for example, at time t2, when the liquid level OL of the lubricating oil LO in the tank 2 reaches the highest level (H), the control unit 8 ends the oil introduction process S3 shown in Fig. 2, and executes the next negative pressure evaporation process S4.

[0037] In this negative pressure evaporation process S4, the control unit 8 controls the plurality of solenoid valves 7 to open and close the gas introduction valve Vgi while opening the gas outlet valve Vgo and closing the oil introduction valve Voi and oil outlet valve Voo. Specifically, the control unit 8 opens and closes the gas introduction valve Vgi so as to maintain the internal pressure Pt of the tank 2 at a predetermined negative pressure VP, for example. More specifically, the control unit 8 performs feedback control of the internal pressure Pt of the tank 2, for example, and controls the opening degree of the gas introduction valve Vgo between a closed state (C) and an open state (O) so as to maintain the internal pressure Pt of the tank 2 at the predetermined negative pressure VP.

[0038] Here, the predetermined negative pressure VP in the negative pressure evaporation process S4 is set, for example, to a pressure suitable for the evaporation of water and fuel mixed in the lubricating oil LO. This predetermined negative pressure VP is set, for example, to a pressure lower than the internal pressure of the crankcase CC of the internal combustion engine ICE during operation. More specifically, for example, if the internal pressure of the crankcase CC of the internal combustion engine ICE during operation is minus several kilopascals in gauge pressure, the predetermined negative pressure VP of the tank 2 can be set, for example, to minus several dozen kilopascals in gauge pressure.

[0039] In the negative pressure evaporation process S4, the control unit 8 maintains the internal pressure Pt of the tank 2 at a predetermined negative pressure VP for a predetermined period, for example, from time t2 to time t3. This predetermined period is set, for example, to the period required to evaporate the amounts of water and fuel calculated in the above-mentioned process S1. The period required to evaporate the water and fuel can be calculated, for example, based on the internal pressure Pt of the tank 2, the temperature of the lubricating oil LO, and the amounts of water and fuel mixed in.

[0040] 1, for example, if the tank 2 has a heating device 23, the control unit 8 may control the heating device 23 in the negative pressure evaporation process S4 to heat the lubricating oil LO inside the tank 2 to a predetermined temperature. The predetermined temperature of the lubricating oil LO is set to a temperature at which water and fuel mixed in the lubricating oil LO can be sufficiently evaporated when the internal pressure Pt of the tank 2 is maintained at a predetermined negative pressure VP, for example.

[0041] By executing the negative pressure evaporation process S4, the water and fuel mixed in the lubricating oil LO in the tank 2 evaporate, and the liquid level OL of the lubricating oil LO gradually drops, as shown in the top graph of Fig. 4. For example, when a predetermined period has elapsed from time t2 when the negative pressure evaporation process S4 was started, the control unit 8 ends the negative pressure evaporation process S4, and executes the next oil discharge process S5, as shown in Fig. 2.

[0042] When this oil discharge process S5 is started, the control unit 8 closes the gas discharge valve Vgo to change it from the open state (O) to the closed state (C) at time t3, as shown in the bottom and fourth graphs from the bottom in Fig. 4, and maintains the closed state (C) of the oil introduction valve Voi. In addition, the control unit 8 opens the gas introduction valve Vgi and the oil introduction valve Voo to change it from the closed state (C) to the open state (O) at time t3, as shown in the second and third graphs from the bottom in Fig. 4, for example.

[0043] As a result, the control unit 8 discharges the lubricating oil LO from the tank 2 to the oil pan OP. Specifically, air is introduced into the tank 2 from the intake passage IP via the gas introduction passage 5 and the gas discharge valve Vgo in the open state (O). As a result, as shown in the second graph from the top in FIG. 4, the internal pressure Pt of the tank 2 rises from the predetermined negative pressure VP and returns to an internal pressure Pt that is approximately equal to the atmospheric pressure AP.

[0044] Furthermore, the lubricating oil LO inside the tank 2 flows in a flow direction Oo from the tank 2 to the oil pan OP through the oil discharge passage 6 and the open oil discharge valve Voo, for example, due to the action of gravity, and is discharged from inside the tank 2 to the oil pan OP. As a result, for example, as shown in the top graph of Figure 4, the liquid level OL of the lubricating oil LO inside the tank 2 gradually decreases and reaches the lowest level (L) at time t4. Thereafter, the control unit 8 executes a process S6 for updating the amounts of water and fuel mixed in, for example, as shown in Figure 2.

[0045] In this process S6, the control unit 8 updates the amount of water and fuel mixed into the lubricating oil LO, for example, by subtracting the amount of water and fuel evaporated in the previous negative pressure evaporation process S4 from the amount of water and fuel mixed into the entire lubricating oil LO before the previous negative pressure evaporation process S4 was performed. More specifically, the control unit 8 calculates and updates the amount of water mixed into the lubricating oil LO, for example, based on the following equation (1).

[0046] Amount of water mixed in = Previous amount of water mixed in x (1 - amount of lubricating oil in tank / total amount of lubricating oil)...(1)

[0047] The control unit 8 can also calculate and update, for example, the amount of fuel mixed into the lubricating oil LO in the same way as the amount of water mixed in. Thereafter, the control unit 8 executes, for example, a process S7 as shown in FIG. 2, for determining whether the evaporation of the water and fuel mixed into the lubricating oil LO is complete.

[0048] In this process S7, the control unit 8 compares, for example, a threshold value for the amount of mixed water stored in advance in memory with the amount of mixed water in the updated lubricant oil L. Similarly, the control unit 8 compares, for example, a threshold value for the amount of mixed fuel stored in advance in memory with the amount of mixed fuel in the updated lubricant oil L.

[0049] In this process S7, the control unit 8 determines that the evaporation of the water or fuel mixed in the lubricating oil LO is not complete (NO) if, for example, the amount of water mixed in after the update exceeds a threshold value or the amount of fuel mixed in after the update exceeds a threshold value. In this case, the control unit 8 sequentially repeats, for example, the oil introduction process S3, the negative pressure evaporation process S4, the oil discharge process S5, and the process S6 for updating the amounts of mixed water and fuel.

[0050] On the other hand, in the above-mentioned process S7, the control unit 8 determines that the evaporation of the water and fuel mixed in the lubricating oil LO is complete (YES) if, for example, the amount of water mixed in after the update is equal to or less than a threshold value and the amount of fuel mixed in after the update is equal to or less than a threshold value. In this case, the control unit 8 ends the process flow shown in Fig. 2, for example, and repeats the process flow shown in Fig. 2 at a predetermined interval until the start switch of the vehicle equipped with the internal combustion engine ICE is turned off.

[0051] The operation of the lubricant oil dilution suppression device 1 of this embodiment will be described below.

[0052] The lubricant oil dilution suppression device 1 of this embodiment includes a tank 2 disposed inside or outside the crankcase CC of the internal combustion engine ICE. The lubricant oil dilution suppression device 1 also includes a gas outlet path 3 that discharges gas from inside the tank 2 to outside the tank 2, and an oil introduction path 4 that introduces lubricant oil LO from an oil pan OP of the internal combustion engine ICE into the inside of the tank 2. The lubricant oil dilution suppression device 1 also includes a gas introduction path 5 that introduces gas from outside the tank 2 to inside the tank 2, and an oil introduction path 6 that discharges lubricant oil LO from the tank 2 to the oil pan OP. The lubricant oil dilution suppression device 1 also includes solenoid valves 7 provided in the gas introduction path 3, oil introduction path 4, gas introduction path 5, and oil introduction path 6, respectively, and a control unit 8 that individually controls the opening and closing of these solenoid valves 7.

[0053] With this configuration, the lubricating oil dilution suppression device 1 of this embodiment can use the control unit 8 to control the opening and closing of the solenoid valves 7 provided in the gas outlet passage 3, the oil introduction passage 4, the gas introduction passage 5, and the oil introduction passage 6. This allows the gas inside the tank 2 to be discharged to the outside of the tank 2 via the gas outlet passage 3, thereby reducing the internal pressure Pt of the tank 2, and allows the lubricating oil LO to be introduced from the oil pan OP into the tank 2 via the oil introduction passage 4.

[0054] Furthermore, the internal pressure Pt of the tank 2 can be maintained at a predetermined negative pressure VP by introducing a predetermined amount of gas from the outside of the tank 2 into the inside of the tank 2 through the gas introduction path 5 while discharging the gas inside the tank 2 to the outside of the tank 2 through the gas discharge path 3. As a result, the water and fuel mixed in the lubricating oil LO can be efficiently evaporated inside the tank 2.

[0055] Furthermore, by introducing gas from the outside of the tank 2 into the inside of the tank 2 via the gas introduction passage 5, the lubricating oil LO can be discharged from the inside of the tank 2 to the oil pan OP via the oil discharge passage 6. Therefore, according to this embodiment, it is possible to provide a lubricating oil dilution suppression device 1 that can evaporate water and fuel mixed in the lubricating oil LO inside the tank 2 and suppress an increase in the dilution rate of the lubricating oil LO, even when the internal combustion engine ICE is driven intermittently for short periods of time and cold starts are repeated.

[0056] In the lubricant oil dilution suppression device 1 of this embodiment, the solenoid valve 7 includes a gas outlet valve Vgo that opens and closes the gas outlet passage 3, an oil introduction valve Voi that opens and closes the oil introduction passage 4, a gas introduction valve Vgi that opens and closes the gas introduction passage 5, and an oil introduction valve Voo that opens and closes the oil introduction passage 6. The control unit 8 sequentially executes an oil introduction process S3, a negative pressure evaporation process S4, and an oil introduction process S5. The oil introduction process S3 is a process for introducing the lubricant oil LO from the oil pan OP to the tank 2 by opening the gas outlet valve Vgo and the oil introduction valve Voi and closing the gas introduction valve Vgi and the oil introduction valve Voo. The negative pressure evaporation process S4 is a process for maintaining the internal pressure Pt of the tank 2 at a predetermined negative pressure VP by opening and closing the gas outlet valve Vgo and the oil introduction valve Voi and the oil introduction valve Voo. The oil discharge process S5 is a process for discharging the lubricating oil LO from the tank 2 to the oil pan OP by closing the gas discharge valve Vgo and the oil introduction valve Voi and opening the gas introduction valve Vgi and the oil discharge valve Voo.

[0057] With this configuration, the lubricant oil dilution suppression device 1 of this embodiment can execute the oil introduction process S3 by the control unit 8. This allows the gas inside the tank 2 to be discharged to the outside of the tank 2 via the gas outlet path 3 and the gas outlet valve Vgo in the open state (O), thereby reducing the internal pressure Pt of the tank 2. As a result, the lubricant oil LO can be introduced from the oil pan OP into the tank 2 via the oil introduction path 4 and the oil introduction valve Voi in the open state (O).

[0058] Furthermore, after the lubricating oil LO is introduced into the tank 2, the control unit 8 can execute a negative pressure evaporation process S4. This allows the gas inside the tank 2 to be discharged to the outside of the tank 2 via the gas outlet path 3 and the gas outlet valve Vgo in the open state (O), while a predetermined amount of gas can be introduced from the outside of the tank 2 into the tank 2 via the gas introduction path 5 and the gas introduction valve Vgi. As a result, the internal pressure Pt of the tank 2 can be maintained at a predetermined negative pressure VP, and water and fuel mixed in the lubricating oil LO introduced into the tank 2 can be effectively evaporated and discharged to the outside of the tank 2 via the gas outlet path 3 and the gas outlet valve Vgo.

[0059] Furthermore, after the water and fuel mixed in the lubricating oil LO introduced into the tank 2 have sufficiently evaporated, the control unit 8 can execute the oil discharge process S5. As a result, gas is introduced from the outside of the tank 2 into the inside of the tank 2 via the gas introduction path 5 and the gas introduction valve Vgi in the open state (O), and the lubricating oil LO from which the mixed water and fuel have been sufficiently removed is discharged from the inside of the tank 2 to the oil pan OP via the oil discharge path 6 and the oil discharge valve Voo in the open state (O).

[0060] By repeatedly executing the oil introduction process S3, the negative pressure evaporation process S4, and the oil discharge process S5, the water and fuel mixed in the lubricating oil LO stored in the oil pan OP can be evaporated and sufficiently removed. Therefore, the lubricating oil dilution suppression device 1 of this embodiment can effectively suppress an increase in the dilution rate of the lubricating oil LO.

[0061] In addition, if the lubricating oil dilution suppression device 1 of this embodiment further includes a heating device 23 that heats the lubricating oil LO inside the tank 2, the control unit 8 can control the heating device 23 in the negative pressure evaporation process S4 to heat the lubricating oil LO to a predetermined temperature.

[0062] With this configuration, the lubricant oil dilution suppression device 1 of this embodiment can more effectively evaporate and remove water and fuel mixed in the lubricant oil LO in the negative pressure evaporation process S4. Therefore, the lubricant oil dilution suppression device 1 of this embodiment can more effectively suppress an increase in the dilution rate of the lubricant oil LO even when the internal combustion engine ICE is driven intermittently for short periods of time and cold starts are repeated.

[0063] Furthermore, when the downstream end of the gas discharge path 3, opposite to the upstream end connected to the tank 2, is connected to the suction port of the vacuum pump Pv, the internal pressure Pt of the tank 2 can be reduced by the vacuum pump Pv. Therefore, in the negative pressure evaporation process S4, it is possible to easily reduce the internal pressure Pt of the tank 2 to the predetermined negative pressure VP.

[0064] As described above, according to this embodiment, it is possible to provide a lubricant oil dilution suppression device 1 that can suppress an increase in the dilution rate of the lubricant oil LO even when the internal combustion engine ICE is driven intermittently for a short period of time and cold starts are repeated. Note that the lubricant oil dilution suppression device according to the present disclosure is not limited to the configuration of the lubricant oil dilution suppression device 1 according to the embodiment described above. Below, modifications of the lubricant oil dilution suppression device 1 according to the embodiment described above will be described with reference to FIGS. 5 and 6 in addition to FIGS. 1 to 4.

[0065] The lubricant oil dilution suppression device 1 of each modified example described below differs from the lubricant oil dilution suppression device 1 of the above-described embodiment in the processing flow of the control unit 8. The other configurations of the lubricant oil dilution suppression device 1 of each modified example are the same as those of the lubricant oil dilution suppression device 1 of the above-described embodiment, so similar parts are given the same reference numerals and descriptions thereof will be omitted.

[0066] Fig. 5 is a flow chart showing a modified example of the processing flow by the control unit 8 of the lubricant dilution suppression device 1 of Fig. 1. In this modified example, the vehicle equipped with the internal combustion engine ICE shown in Fig. 1 is, for example, a PHEV that can be connected to an external power source, or an EV that has the internal combustion engine ICE as a generator.

[0067] In the modification shown in Fig. 5, when the control unit 8 determines in the above-mentioned process S2 that the water and fuel mixed in the lubricating oil LO need to be evaporated (YES), the control unit 8 executes process S8 for determining whether or not the vehicle equipped with the internal combustion engine ICE is connected to an external power source. When the control unit 8 determines in this process S8 that the vehicle is not connected to an external power source (NO), the control unit 8 ends the process flow shown in Fig. 5.

[0068] On the other hand, in process S8, if the control unit 8 determines that the vehicle is connected to an external power source (YES), it executes the above-mentioned oil introduction process S3 through process S6 for updating the amounts of mixed water and fuel. Here, for example, in the oil introduction process S3, the control unit 8 operates the heating device 23 using the external power source to heat the lubricating oil LO inside the tank 2. Also, for example, in the oil introduction process S3 and the negative pressure evaporation process S4, the control unit 8 operates the vacuum pump Pv connected to the downstream end of the gas outlet path 3 using the external power source.

[0069] Thereafter, the control unit 8 executes step S7 to determine whether the water and fuel mixed in the lubricating oil LO have completely evaporated, as in the previous embodiment. In the modification shown in Fig. 5, the control unit 8 also determines in step S7 whether the amount of evaporated fuel has reached the limit amount that can be adsorbed by the three-way catalyst TC, or whether the negative pressure evaporation process S4 needs to be interrupted because the connection between the vehicle and the external power source has been cut off, for example.

[0070] In process P7, if the control unit 8 determines that the evaporation of water or fuel is not complete and that there is no need to interrupt the negative pressure evaporation process S4 (NO), the control unit 8 repeatedly executes the above-described oil introduction process S3 to process S7. On the other hand, in process P7, if the control unit 8 determines that the evaporation of water or fuel is complete or that there is a need to interrupt the negative pressure evaporation process S4 (YES), the control unit 8 ends the process flow shown in FIG.

[0071] As described above, in the modified example shown in Figure 5, the control unit 8 of the lubricant oil dilution suppression device 1 executes the oil introduction process S3, the negative pressure evaporation process S4, and the oil extraction process S5 when a vehicle equipped with an internal combustion engine ICE is connected to an external power source.

[0072] 5, even when the internal combustion engine ICE is not operating and the temperature of the internal combustion engine ICE is low, such as when the vehicle is being charged, the water and fuel mixed in the lubricating oil LO can be evaporated to suppress an increase in the dilution rate of the lubricating oil LO. Furthermore, by using an external power source, there is no need to drive the internal combustion engine ICE, which reduces carbon dioxide emissions.

[0073] FIG. 6 is a flow chart showing a modified example of the flow of processing by the control unit 8 of the lubricant oil dilution suppressing device 1 of FIG.

[0074] The control unit 8 of the lubricant dilution suppression device 1 of the modified example shown in Figure 6 differs from the lubricant dilution suppression device 1 of the modified example shown in Figure 5 in that after process S8 of determining whether the vehicle is connected to an external power source, the control unit 8 executes process S9 of heating the three-way catalyst TC.

[0075] In the example shown in FIG. 6, for example, when the control unit 8 determines in process S2 that water or fuel mixed in the lubricating oil LO needs to be evaporated (YES), and determines in process S8 that the vehicle is connected to an external power source (YES), it executes process S9 to heat the three-way catalyst TC.

[0076] In this process S9, the control unit 8 controls, for example, the electric heater EH that heats the three-way catalyst TC to heat the three-way catalyst TC to its activation start temperature. The control unit 8 then executes process S6, which updates the amounts of water and fuel mixed in from the oil introduction process S3. Here, the fuel evaporated from the lubricating oil LO in the negative pressure evaporation process S4 is purified by the three-way catalyst TC heated by the electric heater EH.

[0077] Thereafter, the control unit 8 executes, for example, a process S7 for determining whether evaporation has been completed or interrupted. In this process S7, if the control unit 8 determines that the amount of water and fuel mixed into the lubricant oil LO updated in the previous process S6 is equal to or less than a threshold value, or that the connection between the vehicle and the external power source has been released (YES), the control unit 8 ends the process flow shown in FIG.

[0078] As described above, in the modified example shown in Figure 6, the control unit 8 of the lubricant dilution suppression device 1 heats the three-way catalyst TC, which is an electrically heated catalyst provided in the exhaust passage of the internal combustion engine ICE, during the negative pressure evaporation process S4 when the vehicle is connected to an external power source.

[0079] With this configuration, the lubricant oil dilution suppression device 1 of this embodiment can purify harmful substances such as hydrocarbons generated by the evaporation of fuel mixed in the lubricant oil LO during the negative pressure evaporation process S4 using the three-way catalyst TC heated using an external power source. This eliminates the restriction on the amount of harmful substances adsorbed by the three-way catalyst TC when the internal combustion engine ICE is not operating, making it possible to evaporate all of the fuel mixed in the lubricant oil LO.

[0080] The preferred embodiments of the present invention have been described above in detail. However, the present invention is not limited to the above-described embodiments. Various modifications or substitutions may be applied to the above-described embodiments without departing from the scope of the present invention. [Explanation of symbols]

[0081] 1: Lubricating oil dilution suppression device, 2: tank, 23: heating device, 3: gas discharge path, 4: oil introduction path, 5: gas introduction path, 6: oil discharge path, 7: solenoid valve, 8: control unit, CC: crankcase, EP: exhaust passage, ICE: internal combustion engine, LO: lubricating oil, OP: oil pan, S3: oil introduction process, S4: negative pressure evaporation process, S5: oil discharge process, TC: three-way catalyst (electrically heated catalyst), Vgi: gas introduction valve, Vgo: gas discharge valve, Voi: oil introduction valve, Voo: oil discharge valve, VP: specified negative pressure.

Claims

1. a tank disposed outside or inside a crankcase of an internal combustion engine; a gas outlet path that discharges gas from the inside of the tank to the outside of the tank; an oil introduction passage for introducing lubricating oil from an oil pan of the internal combustion engine into the tank; a gas introduction path that introduces gas from the outside of the tank to the inside of the tank; an oil outlet passage for leading the lubricating oil from the tank to the oil pan; an electromagnetic valve provided in each of the gas discharge passage, the oil introduction passage, the gas introduction passage, and the oil discharge passage; and a control unit that individually controls the opening and closing of the solenoid valves. Lubricant dilution suppression device.

2. the solenoid valve includes a gas discharge valve that opens and closes the gas discharge passage, an oil introduction valve that opens and closes the oil introduction passage, a gas introduction valve that opens and closes the gas introduction passage, and an oil discharge valve that opens and closes the oil discharge passage, The control unit sequentially executes an oil introduction process in which the gas outlet valve and the oil introduction valve are opened and the gas introduction valve and the oil introduction valve are closed to introduce the lubricating oil from the oil pan to the tank; a negative pressure evaporation process in which the gas outlet valve is opened and the gas introduction valve is opened and closed with the oil introduction valve and the oil introduction valve closed to maintain the internal pressure of the tank at a predetermined negative pressure; and an oil introduction process in which the gas outlet valve and the oil introduction valve are closed and the gas introduction valve and the oil introduction valve are opened to introduce the lubricating oil from the tank to the oil pan. The lubricating oil dilution suppression device according to claim 1 .

3. The lubricating oil tank further includes a heating device for heating the lubricating oil inside the tank. The control unit controls the heating device in the negative pressure evaporation process to heat the lubricating oil to a predetermined temperature. The lubricating oil dilution suppression device according to claim 2.

4. the control unit executes the oil introduction process, the negative pressure evaporation process, and the oil discharge process when the vehicle equipped with the internal combustion engine is connected to an external power source. The lubricating oil dilution suppression device according to claim 2 or 3.

5. the control unit, during the negative pressure evaporation process, heats an electrically heated catalyst provided in an exhaust passage of the internal combustion engine when the vehicle is connected to the external power supply. The lubricating oil dilution suppression device according to claim 4.

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