Internal combustion engine

Abstract

This invention provides an internal combustion engine that can suppress blockage of the oil inflow path caused by emulsions drawn into the filter and vapor lock caused by air drawn into the filter. In the internal combustion engine of this invention, the distance between the first intake port in the vertical direction and the lowest part of the oil pan is greater than the distance between the second intake port in the vertical direction and the lowest part. The valve position of the flow path switching valve can be switched between a first position and a second position. The first position is a position that connects the first intake port to the oil pump and disconnects the second intake port from the oil pump. The second position is a position that disconnects the first intake port from the oil pump and connects the second intake port to the oil pump. The control device switches the valve position to the first position (S11-S12) when the oil pump starts operating, and switches the valve position to the second position (S13-S14) after the internal combustion engine preheating is completed.

Description

Technical Field

[0001] This invention relates to an internal combustion engine. Background Technology

[0002] Patent document 1 discloses a filter for drawing in oil stored in the oil pan of an internal combustion engine and sending it to an oil pump.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2016-156359 Summary of the Invention

[0004] Sometimes, water mixes with the oil in the oil pan. When the oil and water are stirred by the oil pump, they produce an emulsion with a higher viscosity than the oil. The emulsion has a higher specific gravity than the oil, so it settles at the bottom of the oil pan. At low temperatures, this emulsion can sometimes freeze.

[0005] When the oil pump resumes operation, the filter draws in frozen emulsions, which can sometimes cause blockages in the oil flow path. Since the emulsions settle at the bottom of the oil pan, increasing the distance between the filter inlet and the bottom of the oil pan reduces the likelihood of the filter drawing in emulsions. By inhibiting the intake of emulsions, blockages in the oil flow path caused by frozen emulsions are less likely to occur.

[0006] On the other hand, in internal combustion engines installed in vehicles, the inlet of the filter is exposed to air due to the tilt of the oil level, causing air to mix into the oil flowing in the inflow path (hereinafter referred to as airlock). In order to suppress the intake of emulsions, the distance between the filter inlet and the bottom of the oil pan is increased. However, the filter inlet is easily exposed to air, thus making airlock more likely to occur.

[0007] An internal combustion engine for solving the above-mentioned problems is an on-vehicle internal combustion engine comprising an oil pan, an oil pump, and a filter for supplying oil from the oil pan to the oil pump. The internal combustion engine further comprises: a flow path switching valve actuated by energization; and a control device for controlling the flow path switching valve. The filter includes: a first pipe having a first intake port disposed within the oil pan and connected to the oil pump; and a second pipe having a second intake port disposed within the oil pan and connected to the oil pump. The vertical distance between the first intake port and the lowest part of the oil pan is greater than the vertical distance between the second intake port and the lowest part. The valve position of the flow path switching valve is adjustable in the first... The control device switches between a first position and a second position. The first position is a position that connects the first intake port to the oil pump and disconnects the second intake port from the oil pump. The second position is a position that disconnects the first intake port from the oil pump and connects the second intake port to the oil pump. The control device performs the following processes: a first switching process, at any time when the oil pump starts operating and when the oil pump stops operating, controlling the flow path switching valve to switch the valve position from the second position to the first position; and a second switching process, after the preheating of the internal combustion engine is completed, controlling the flow path switching valve to switch the valve position from the first position to the second position.

[0008] Invention Effects

[0009] The aforementioned internal combustion engine can suppress the blockage of the oil inflow path caused by emulsions drawn into the filter and the occurrence of air lock caused by air drawn into the filter. Attached Figure Description

[0010] Figure 1 This is a schematic structural diagram of an internal combustion engine according to one embodiment.

[0011] Figure 2 This is a flowchart illustrating the processing of the control device based on the first embodiment.

[0012] Figure 3 This is a flowchart illustrating the processing of the control device based on the second embodiment. Detailed Implementation

[0013] <First Embodiment>

[0014] The following is for reference. Figure 1 and Figure 2 The first embodiment of the internal combustion engine will be described.

[0015] <Structure of an Internal Combustion Engine>

[0016] The vehicle is equipped with an internal combustion engine. Figure 1The internal combustion engine 10 shown is an on-board internal combustion engine mounted in a vehicle. The internal combustion engine 10 serves, for example, as a power source for the vehicle. The fuel for the internal combustion engine 10 is, for example, hydrogen.

[0017] The internal combustion engine 10 includes a cylinder that serves as a combustion chamber for burning a combustion mixture. The internal combustion engine 10 also includes a piston that reciprocates within the combustion chamber, an output shaft that outputs rotational torque, and a connecting rod connecting the piston and the output shaft. When the internal combustion engine 10 is running, hydrogen as fuel is injected into the combustion chamber, and the piston reciprocates due to the combustion of the fuel within the combustion chamber. The reciprocating motion of the piston is converted into the rotational motion of the output shaft via the connecting rod and the output shaft.

[0018] The internal combustion engine 10 includes an oil pan 21, an oil pump 22, and a filter 23. The oil pan 21 is located on the lower side of the internal combustion engine 10. The oil pan 21 stores oil L. Figure 1 In this example, the oil pan 21 has a first housing 24 and a second housing 25. The first housing 24 forms the lowest part 21L of the oil pan 21 in the vertical direction. The second housing 25 is fixed to the upper side of the first housing 24. The second housing 25 forms the highest part 21H of the oil pan 21 in the vertical direction.

[0019] The oil pump 22 is, for example, a pump driven by the rotational force of its output shaft. For instance, in this case, pulleys are mounted on both the oil pump 22 and the output shaft. A drive belt is wound around these pulleys. The rotational force of the output shaft is transmitted to the oil pump 22 via the drive belt. The oil pump 22 is, for example, a pump driven by an electric motor.

[0020] Oil pump 22 draws oil L from oil pan 21 via filter 23. The oil L drawn by oil pump 22 is supplied to supply section 12. Supply section 12 is, for example, a drive unit that generates friction during the operation of the internal combustion engine 10, such as the piston, connecting rod, and output shaft, or a hydraulic device that operates hydraulically. Oil L circulates through supply section 12 for lubrication and other purposes before flowing into oil pan 21.

[0021] Filter 23 delivers oil L from oil pan 21 to oil pump 22. Filter 23 includes suction pipe 26. One end of suction pipe 26 is connected to oil pump 22. The other end of suction pipe 26 branches into pipe 27 and pipe 28.

[0022] The filter 23 includes a first pipe 27 and a second pipe 28. The first pipe 27 is connected to the oil pump 22. The first pipe 27 is connected to the oil pump 22, for example, via a suction pipe 26. The first pipe 27 has a first suction port 29. The first suction port 29 is disposed within the oil pan 21. At least when the vehicle is stationary, the first suction port 29 is immersed in the oil L.

[0023] The second pipe 28 is connected to the oil pump 22. The second pipe 28 is connected to the oil pump 22, for example, via the suction pipe 26. The second pipe 28 has a second suction port 31. The second suction port 31 is disposed within the oil pan 21. The second suction port 31 is immersed in the oil L.

[0024] The first intake port 29 is located higher than the second intake port 31 in the vertical direction. The distance L1 between the first intake port 29 and the lowest part 21L of the oil pan 21 in the vertical direction is greater than the distance L2 between the second intake port 31 and the lowest part 21L in the vertical direction. Preferably, when the third distance L3 from the lowest part 21L to the highest part 21H of the oil pan 21 is set to h, the first distance L1 is h / 5 or more, and the second distance L2 is less than h / 5.

[0025] The internal combustion engine 10 also includes a flow path switching valve 40 and a control device 50. The flow path switching valve 40 is actuated by energization. The flow path switching valve 40 is, for example, a solenoid valve. The flow path switching valve 40 is disposed between the intake pipe 26 and the first pipe 27 and the second pipe 28.

[0026] The flow path switching valve 40 can be switched between a first position and a second position. The first position connects the first suction port 29 to the oil pump 22 and disconnects the connection between the second suction port 31 and the oil pump 22. When the flow path switching valve 40 is in the first position, the oil pump 22, suction pipe 26, and first pipe 27 are connected. When the flow path switching valve 40 is in the first position, the oil pump 22 draws oil L from the first suction port 29. The second position disconnects the connection between the first suction port 29 and the oil pump 22 and connects the second suction port 31 and the oil pump 22. When the flow path switching valve 40 is in the second position, the oil pump 22, suction pipe 26, and second pipe 28 are connected. When the flow path switching valve 40 is in the second position, the oil pump 22 draws oil L from the second suction port 31.

[0027] The control unit 50 includes a processing circuit (not shown) and a storage device. The processing circuit consists of a CPU that executes processing according to a program and its peripheral circuitry. The storage device consists of a ROM storing a program, a volatile RAM capable of temporarily writing data, and a non-volatile storage device capable of writing data. The storage device stores information related to the control of the internal combustion engine 10.

[0028] The control device 50 controls the flow path switching valve 40. The control device 50 controls the valve position of the flow path switching valve 40, for example, by outputting a control signal to the flow path switching valve 40 indicating the valve position of the flow path switching valve 40.

[0029] The internal combustion engine 10 includes, for example, an oil temperature acquisition unit 51, an output pressure acquisition unit 52, a transit time acquisition unit 53, and a moisture content acquisition unit 54. The oil temperature acquisition unit 51, the output pressure acquisition unit 52, the transit time acquisition unit 53, and the moisture content acquisition unit 54 each output the acquisition results to the control device 50.

[0030] The oil temperature acquisition unit 51 acquires the oil temperature LT of the oil L inside the oil pan 21. The oil temperature acquisition unit 51 includes, for example, an oil temperature sensor.

[0031] The discharge pressure acquisition unit 52 acquires the discharge pressure DP of the oil pump 22. The discharge pressure acquisition unit 52 includes, for example, a hydraulic sensor.

[0032] The elapsed time acquisition unit 53 acquires the elapsed time ED from the start of operation of the oil pump 22 until the discharge pressure DP of the oil pump 22 rises to a predetermined pressure. The elapsed time acquisition unit 53 may include, for example, a timer. The elapsed time acquisition unit 53 may be a function of the control device 50.

[0033] The water content acquisition unit 54 acquires the water content MC of the oil L inside the oil pan 21. The water content acquisition unit 54 includes, for example, a sensor for detecting the water content MC of the oil L. An example of a sensor for detecting the water content MC is an electrostatic capacitive sensor.

[0034] Oil pump 22 agitates the oil L in oil pan 21 with water mixed in oil pan 21, thereby producing an emulsion M with a higher viscosity than oil L. The emulsion M that settles at the bottom of oil pan 21 sometimes freezes at low temperatures. The frozen emulsion M has a higher water content MC than the unfrozen form. When hydrogen is used as fuel for internal combustion engine 10, the amount of water mixed into oil L is greater than when gasoline is used as fuel because the combustion gases contain a large amount of water.

[0035] The emulsion M has a higher water content (MC) than the oil L, and therefore settles at the bottom of the oil pan 21. Preferably, the water content acquisition unit 54 is configured to acquire the water content (MC) at the bottom of the oil pan 21. When the water content (MC) detected by the sensor of the water content acquisition unit 54 is high, compared to when the water content (MC) is low, the emulsion M is more likely to settle at the bottom of the oil pan 21 or the settled emulsion M may freeze. Furthermore, when the internal combustion engine 10 starts operating, the oil L circulates between the oil pan 21 and the oil supply section 12. The temperature of the supply section 12 is higher than the oil temperature (LT) of the oil L in the oil pan 21, so the frozen emulsion M melts due to the temperature rise of the oil L in the oil pan 21.

[0036] <Processing based on control device>

[0037] The control device 50 performs a first switching process and a second switching process. The first switching process involves controlling the flow path switching valve 40 to switch its valve position from the second position to the first position. The control device 50 performs the first switching process when the oil pump 22 starts operating. The operation of the oil pump 22 begins, for example, when the internal combustion engine 10 starts operating. In the first switching process, the control device 50 outputs a control signal to the flow path switching valve 40 to switch its valve position from the second position to the first position.

[0038] The second switching process involves controlling the flow path switching valve 40 to switch its valve position from position 1 to position 2. The control device 50 performs the second switching process after the preheating of the internal combustion engine 10 is complete. The control device 50 determines the completion of preheating of the internal combustion engine 10, for example, based on the oil temperature LT of the oil L reaching a predetermined temperature. The control device 50 also determines the completion of preheating based on the cooling water temperature of the internal combustion engine 10 reaching a predetermined temperature. During the second switching process, the control device 50 outputs a control signal to the flow path switching valve 40 to switch its valve position from position 1 to position 2.

[0039]

[0040] Figure 2 This describes a series of processes executed by the control device 50 in this embodiment. The control device 50 executes these processes repeatedly. Figure 2 The processing.

[0041] In step S11, the control device 50 determines whether the oil pump 22 has started operating. For example, if the internal combustion engine 10 has started operating, the control device 50 determines that the oil pump 22 has started operating. When the oil pump 22 has started operating (step S11: Yes), the control device 50 executes the processing in step S12. When the oil pump 22 has not started operating (step S11: No), the control device 50 terminates the process. Figure 2 The processing.

[0042] After the control device 50 performs the first switching process in step S12, it performs the process in step S13.

[0043] In step S13, the control device 50 determines whether the preheating of the internal combustion engine 10 has ended. For example, if the oil temperature LT of the oil L in the oil pan 21 is above the third predetermined value PV3, the control device 50 determines that the preheating of the internal combustion engine 10 has ended. The control device 50 obtains the oil temperature LT from the oil temperature acquisition unit 51. When the preheating of the internal combustion engine 10 has ended (step S13: Yes), the control device 50 executes the processing of step S14. When the preheating of the internal combustion engine 10 has not ended (step S13: No), the control device 50 repeats the processing of step S13.

[0044] After the control device 50 performs the second switching process in step S14, it ends. Figure 2 The processing.

[0045] <Function and Effects of This Implementation Method>

[0046] (1) Before the preheating of the internal combustion engine 10 is completed, the control device 50 outputs a control signal to the flow path switching valve 40 to set the valve position of the flow path switching valve 40 to the first position. Since the first distance L1 is greater than the second distance L2, the first intake port 29 is less likely to draw in the frozen emulsion M that has settled at the bottom of the oil pan 21. As a result, the emulsion M in the flow path of the oil L is less likely to cause blockage.

[0047] After the internal combustion engine 10 has finished preheating, the control device 50 outputs a control signal to the flow path switching valve 40 to set the valve position of the flow path switching valve 40 to the second position. After the internal combustion engine 10 has finished preheating, the frozen emulsion M is more likely to melt, so the emulsion M in the oil L inflow path is less likely to cause blockage. Since the second distance L2 is smaller than the first distance L1, the exposure of the second intake port 31 to air caused by the oil surface tilt is less likely to occur than the exposure of the first intake port 29 to air caused by the oil surface tilt. When oil L is drawn in from the second intake port 31, air lock is less likely to occur compared to when oil L is drawn in from the first intake port 29. According to this embodiment, it is possible to suppress the blockage of the oil L inflow path caused by the filter 23 drawing in emulsion M and the occurrence of air lock caused by the filter 23 drawing in air.

[0048] <Second Implementation>

[0049] The following is for reference. Figure 1 and Figure 3 A second embodiment of the internal combustion engine will be described. Descriptions of structures and structure-based operations identical to those in the first embodiment will be simplified or omitted. In the second embodiment, the conditions for performing the first and second switching processes differ from those in the first embodiment.

[0050] <Processing based on control device>

[0051] The control device 50 of this embodiment performs a first determination process and a first switching process. The first determination process determines whether the elapsed period ED from the start of operation of the oil pump 22 until the discharge pressure DP of the oil pump 22 rises to a first predetermined value PV1 is greater than or equal to a predetermined period PD. The first predetermined value PV1 is, for example, set to the discharge pressure DP under normal operation of the oil pump 22. Normal operation of the oil pump 22 refers to the operation of the oil pump 22 in a state where no emulsion M is generated in the inflow path of the oil L. The first predetermined value PV1 is, for example, 200 kPa. The predetermined period PD is, for example, set to the time required for the oil pump 22 to start under the condition that no emulsion M is generated in the inflow path of the oil L. The predetermined period PD is, for example, 1 sec. The control device 50 performs the first determination process when the valve position of the flow path switching valve 40 is in the second position.

[0052] Preferably, in the first determination process, the control device 50 further determines whether the rate of change CR of the discharge pressure DP per unit time is greater than or equal to a second predetermined value PV2. The rate of change CR is calculated by (XY) / X if the discharge pressure DP at the first moment is X kPa and the discharge pressure DP at the second moment after a unit time has elapsed from the first moment is Y kPa. The second predetermined value PV2 is, for example, set to represent a value indicating blockage of emulsion M in the inflow path of oil L. The second predetermined value PV2 is, for example, 10%.

[0053] In this specification, a change rate CR of PV2 or higher includes cases where the change rate CR is positive and the change rate CR is PV2 or higher, and cases where the change rate CR is negative and the change rate CR is negative PV2 or lower. The change rate CR becomes positive when the emulsion M is blocked in the inflow path of the oil L and the discharge pressure DP at time 2 is lower than the discharge pressure DP at time 1.

[0054] On the other hand, when emulsion M flows into oil pump 22, sometimes the shear force of oil pump 22 acts on emulsion M, causing emulsion M to separate from oil L and water. For example, when emulsion M is blocked in the inflow path of oil L and the discharge pressure DP decreases, the blockage is eliminated through the separation of emulsion M from oil L and water. As a result, the discharge pressure DP at time 2 is higher than the discharge pressure DP at time 1. When emulsion M, which is blocked in the inflow path of oil L, separates, the rate of change CR becomes negative.

[0055] In this embodiment, when the elapsed period ED is a predetermined period PD or higher and the rate of change CR is a second predetermined value PV2 or higher, the control device 50 makes an affirmative determination in the first determination process. When the control device 50 makes an affirmative determination in the first determination process, it performs the first switching process. When the oil pump 22 starts operating, if the control device 50 makes a negative determination in the first determination process, it does not perform the first switching process.

[0056] In this embodiment, the control device 50 performs a second determination process and a second switching process. The second determination process is to determine whether the oil temperature LT of the oil L in the oil pan 21 is above a third predetermined value PV3. The third predetermined value PV3 is, for example, set to the melting temperature of the emulsion M frozen in the oil pan 21. The third predetermined value PV3 is, for example, 100°C. The control device 50 performs the second determination process when the valve position of the flow path switching valve 40 is in the first position.

[0057] Preferably, in the second determination process, the control device 50 further determines whether the water content MC of the oil L at the bottom of the oil pan 21 is less than a fourth predetermined value PV4. The fourth predetermined value PV4 is, for example, set to represent the value of water evaporation within the oil pan 21. The fourth predetermined value PV4 is, for example, 5%.

[0058] In this embodiment, when the oil temperature LT is above the third predetermined value PV3 and the water content MC is less than the fourth predetermined value PV4, the control device 50 makes a positive determination in the second determination process. When the control device 50 makes a positive determination in the second determination process, it performs the second switching process. Regardless of whether the preheating of the internal combustion engine 10 has ended, if the control device 50 in this embodiment makes a negative determination in the second determination process, it does not perform the second switching process.

[0059]

[0060] Figure 3 This describes a series of processes executed by the control device 50 in this embodiment. Figure 3 In this process, steps S22 and S23 correspond to the first determination process. Furthermore, steps S25 and S26 correspond to the second determination process. The control device 50 repeatedly executes this process while the flow path switching valve 40 is in the second position. Figure 3 The processing is omitted. Furthermore, the process described in the first embodiment is omitted. Figure 2 Detailed explanation of the same part of the processing.

[0061] In step S21, control device 50 determines whether oil pump 22 has started operating. If oil pump 22 has started operating (step S21: Yes), control device 50 executes the processing in step S22. If oil pump 22 has not started operating (step S21: No), control device 50 terminates the process. Figure 3 The processing.

[0062] In step S22, the control device 50 determines whether the elapsed period ED from the start of operation of the oil pump 22 until the discharge pressure DP of the oil pump 22 rises to the first predetermined value PV1 is greater than or equal to a predetermined period PD. The control device 50 acquires the elapsed period ED from the elapsed period acquisition unit 53. The elapsed period acquisition unit 53 starts measuring the elapsed period ED, for example, based on the output of the discharge pressure acquisition unit 52. If the elapsed period ED is greater than or equal to the predetermined period PD (step S22: Yes), the control device 50 executes the processing in step S23. If the elapsed period ED is not greater than or equal to the predetermined period PD (step S22: No), the control device 50 terminates the process. Figure 3 The processing.

[0063] In step S23, the control device 50 determines whether the rate of change CR of the discharge pressure DP per unit time is greater than or equal to a second predetermined value PV2. The control device 50 acquires the rate of change CR based on the change in the output of the discharge pressure acquisition unit 52. If the rate of change CR is greater than or equal to the second predetermined value PV2 (step S23: Yes), the control device 50 executes the processing in step S24. If the rate of change CR is not greater than or equal to the second predetermined value PV2 (step S23: No), the control device 50 terminates the process. Figure 3 The processing.

[0064] After the control device 50 performs the first switching process in step S24, it performs the process in step S25.

[0065] In step S25, the control device 50 determines whether the oil temperature LT of the oil L in the oil pan 21 is above the third predetermined value PV3. The control device 50 acquires the oil temperature LT from the oil temperature acquisition unit 51. If the oil temperature LT is above the third predetermined value PV3 (step S25: Yes), the control device 50 executes the processing in step S26. If the oil temperature LT is not above the third predetermined value PV3 (step S25: No), the control device 50 repeats the processing in step S25.

[0066] In step S26, the control device 50 determines whether the water content MC of the oil L at the bottom of the oil pan 21 is less than the fourth predetermined value PV4. The control device 50 obtains the rate of change CR from the water content acquisition unit 54. If the water content MC is less than the fourth predetermined value PV4 (step S26: Yes), the control device 50 executes the processing in step S27. If the water content MC is not less than the fourth predetermined value PV4 (step S26: No), the control device 50 repeats the processing from step S25.

[0067] After the control device 50 performs the second switching process in step S27, it ends. Figure 3 The processing.

[0068] <Function and Effects of This Implementation Method>

[0069] The function and effects of this implementation method are explained.

[0070] (2-1) If frozen emulsion M blocks the inflow path of oil L, oil pump 22 will have difficulty drawing oil L. Therefore, the elapsed period ED from the start of operation of oil pump 22 until the discharge pressure DP of oil pump 22 rises to the first predetermined value PV1 becomes longer. When the elapsed period ED is greater than or equal to the predetermined period PD, control device 50 outputs a control signal to flow path switching valve 40 to set the valve position of flow path switching valve 40 to the first position. As a result, it is possible to suppress the drawing of oil L from the first suction port 29, thereby suppressing the blockage of emulsion M in the inflow path of oil L.

[0071] (2-2) Fluctuations in the discharge pressure DP can easily cause blockage of the emulsion M in the inflow path of the oil L. Regarding this, in the first determination process, if the elapsed period ED is greater than or equal to a predetermined period PD, the control device 50 does not perform the first switching process even if the rate of change CR of the discharge pressure DP per unit time is less than the second predetermined value PV2. As a result, the control device 50 performs the first switching process when the possibility of blockage in the inflow path of the oil L is higher. Therefore, it is possible to suppress the occurrence of airlock as a result of performing the first switching process when no blockage occurs in the inflow path of the oil L.

[0072] (2-3) When the oil pump 22 operates, the oil L circulates between the oil pan 21 and the supply section 12, causing the oil temperature LT of the oil L to rise to the third predetermined value PV3. This increases the likelihood of the frozen emulsion M melting. When the oil temperature LT reaches or exceeds the third predetermined value PV3, the control device 50 outputs a control signal to the flow path switching valve 40 to set the valve position of the flow path switching valve 40 to the second position. As a result, oil L can be drawn in from the second suction port 31 in a state where the melting of the frozen emulsion M does not easily cause blockage of the emulsion M in the flow path of the oil L.

[0073] (2-4) The oil temperature LT of oil L is sometimes uneven within the oil pan 21. Therefore, even if the oil temperature LT of oil L within the oil pan 21 rises to the third specified value PV3, the melting of the emulsion M that is sometimes frozen at the bottom of the oil pan 21 may not occur. When the oil temperature LT is above the third specified value PV3, the control device 50 will not perform the second switching process even if the water content MC of oil L is above the fourth specified value PV4. As a result, the second switching process can be performed while the melting of the frozen emulsion M is in progress.

[0074] <Example of Change>

[0075] This embodiment can be modified as follows. This embodiment and the following modifications can be combined with each other within the scope of technical inconsistency.

[0076] In addition to hydrogen, the internal combustion engine 10 can also use CN fuels such as ethanol and synthetic fuels. Furthermore, the internal combustion engine 10 is not limited to CN fuels.

[0077] • The flow path switching valve 40 is not limited to a solenoid valve. The flow path switching valve 40 can be a valve whose position is switched by rotating the valve body via an electric motor.

[0078] When the oil pump 22 is a pump driven by an electric motor, the start of operation of the oil pump 22 is, for example, when a drive signal is output to the control circuit of the electric motor. The start of operation of the oil pump 22 is, for example, when the main switch of the vehicle is turned on.

[0079] • The control device 50 can perform the first switching process when the oil pump 22 stops operating. The time when the oil pump 22 stops operating is the period from when the main switch of the vehicle is turned off until the next turn-on operation. If the oil pump 22 is a pump driven by an electric motor, the time when the oil pump 22 stops operating is the moment after the output of the drive signal to the control circuit of the electric motor stops.

[0080] • The control device 50 can perform the second switching process when the oil pump 22 stops operating or when the oil pump 22 stops operating.

[0081] • Control device 50 can make a positive determination in the first determination process when the elapsed period ED is greater than or equal to the rate of change CR of the discharge pressure DP per unit time, regardless of the rate of change CR of the discharge pressure DP.

[0082] • Control device 50 can make a positive determination in the second determination process regardless of the water content MC of the oil L in the oil pan 21, when the oil temperature LT is above the third specified value PV3.

[0083] • In the second embodiment, the second determination process can be omitted, and the second switching process can be performed under the same conditions as in the first embodiment.

[0084] In each embodiment, the case where frozen emulsion M clogs the inflow path of oil L is assumed. However, the above structure can also be applied even if unfrozen emulsion M, whose viscosity becomes extremely high at low temperatures, clogs the inflow path of oil L. Furthermore, the above structure can also be applied even if ice formed from the freezing of water mixed in oil L clogs the inflow path of oil L. The freezing of water and the melting of ice can be determined in the same way as in the case of emulsion M. Therefore, the first switching process can be performed based on the blockage caused by ice, and the second switching process can be performed based on the elimination of the ice blockage.

[0085] Symbol Explanation

[0086] 10-Internal combustion engine, 12-Supply section, 21-Oil pan, 22-Oil pump, 23-Filter, 21H-Highest part, 21L-Lowest part, 24-First housing, 25-Second housing, 26-Suction pipe, 27-First pipe, 28-Second pipe, 29-First suction port, 31-Second suction port, 40-Flow path switching valve, 50-Control device, 51-Oil temperature acquisition unit, 52-Discharge pressure acquisition unit, 53-Transmission period acquisition unit, 54-Water content acquisition unit, L-Oil, M-Emulsion, LT-Oil temperature, DP-Discharge pressure, ED-Transmission period, MC-Water content, CR-Rate of change, L1-First distance, L2-Second distance, L3-Third distance, PV1-First specified value, PV2-Second specified value, PV3-Third specified value, PV4-Fourth specified value, PD-Specified period.

Claims

1. An internal combustion engine, comprising an oil pan, an oil pump, and a filter for supplying oil from the oil pan to the oil pump, the internal combustion engine being characterized in that it further comprises: A flow path switching valve, which is actuated by energization; and Control device, which controls the flow path switching valve, The filter includes: The first pipe has a first suction port disposed in the oil pan and connected to the oil pump; and a second pipe, which has a second suction port disposed within the oil sump and connected to the oil pump, The distance between the first intake port in the vertical direction and the lowest part of the oil pan is greater than the distance between the second intake port in the vertical direction and the lowest part. The flow path switching valve can be switched between a first position and a second position. The first position connects the first suction port to the oil pump and disconnects the second suction port from the oil pump. The second position disconnects the first suction port from the oil pump and connects the second suction port to the oil pump. The control device performs the following processing: The first switching process involves controlling the flow path switching valve at any time, either when the oil pump starts operating or when the oil pump stops operating, to switch the valve position from the second position to the first position; and The second switching process involves controlling the flow path switching valve after the preheating of the internal combustion engine is completed, so that the valve position switches from the first position to the second position.

2. An internal combustion engine, comprising an oil pan, an oil pump, and a filter for supplying oil from the oil pan to the oil pump, characterized in that it further comprises: A flow path switching valve, which is actuated by energization; and Control device, which controls the flow path switching valve, The filter includes: The first pipe has a first suction port disposed in the oil pan and connected to the oil pump; and a second pipe, which has a second suction port disposed within the oil sump and connected to the oil pump, The distance between the first intake port in the vertical direction and the lowest part of the oil pan is greater than the distance between the second intake port in the vertical direction and the lowest part. The flow path switching valve can be switched between a first position and a second position. The first position connects the first suction port to the oil pump and disconnects the second suction port from the oil pump. The second position disconnects the first suction port from the oil pump and connects the second suction port to the oil pump. The control device performs the following processing: The first determination process, in the state where the valve position is the second position, determines whether the elapsed period from the start of the operation of the oil pump to the rise of the oil pump's discharge pressure to the first predetermined value is more than a predetermined period; and In the first switching process, when an affirmative determination is made in the first determination process, the flow path switching valve is controlled to switch the valve position from the second position to the first position.

3. The internal combustion engine according to claim 2, characterized in that, The control device further determines whether the rate of change of the discharge pressure per unit time is greater than or equal to a second predetermined value. If the elapsed period is greater than or equal to the predetermined period and the rate of change is greater than or equal to the second predetermined value, an affirmative determination is made in the first determination process.

4. The internal combustion engine according to claim 2 or 3, characterized in that, The control device performs the following processing: The second determination process involves determining, while the valve is in the first position, whether the oil temperature in the oil pan is above the third predetermined value; and In the second switching process, when a positive determination is made in the second determination process, the flow path switching valve is controlled to switch the valve position from the first position to the second position.

5. The internal combustion engine according to claim 4, characterized in that, The control device further determines whether the water content of the oil at the bottom of the oil pan is less than a fourth specified value. When the oil temperature is above the third specified value and the water content is less than the fourth specified value, an affirmative determination is made in the second determination process.

Images