Control device for an internal combustion engine

Abstract

A control device for an internal combustion engine, comprising: a piston injector for injecting lubricating oil onto the back of a piston; and an oil pump for varying the amount of lubricating oil dispensed per revolution, i.e., the unit dispensed quantity. The control device includes a processing circuit. When the oil temperature is below a predetermined temperature, the processing circuit closes an electrically operated valve located in the lubricating oil supply path to the piston injector, thereby stopping the injection of lubricating oil from the piston injector. During the period when the oil temperature is below the predetermined temperature and the injection of lubricating oil from the piston injector is stopped, the processing circuit maintains the unit dispensed quantity of lubricating oil from the oil pump at or above a predetermined amount.

Description

Technical Field

[0001] This invention relates to a control device for an internal combustion engine. Background Technology

[0002] In internal combustion engines, fuel can sometimes mix into the lubricating oil that lubricates the engine's components, causing fuel dilution. If, after fuel dilution, the fuel mixed in with the lubricating oil evaporates, and the fuel-containing blow-by gas is introduced into the engine's intake system, it can cause disturbances in the air-fuel ratio, such as enrichment of the air-fuel mixture.

[0003] Japanese Patent Application Publication No. 2024-041157 discloses a fuel dilution elimination device that eliminates fuel dilution when it occurs. If the device determines that fuel dilution has occurred, it controls the internal combustion engine to operate at a higher speed to promote fuel volatilization, thereby rapidly eliminating fuel dilution. Summary of the Invention

[0004] The aforementioned fuel dilution elimination device can quickly eliminate the generated fuel dilution, but it cannot suppress the generation of fuel dilution itself.

[0005] A control device for an internal combustion engine to solve the above-mentioned problems controls an internal combustion engine, the internal combustion engine comprising: a piston injector for injecting lubricating oil onto the back of a piston; and a variable oil pump for varying the amount of lubricating oil discharged per revolution. The control device includes a processing circuit. The processing circuit of the control device performs the following processing: when the temperature of the lubricating oil, i.e., the oil temperature, is lower than a predetermined temperature, it closes a solenoid valve provided in the lubricating oil supply path to the piston injector to stop the injection of lubricating oil from the piston injector. When the temperature of the lubricating oil, i.e., the oil temperature, is lower than the predetermined temperature, the processing circuit of the control device performs the following control: during the period when the injection of lubricating oil from the piston injector is stopped, the amount of lubricating oil discharged from the variable oil pump is maintained above a predetermined amount.

[0006] According to the control device of the internal combustion engine mentioned above, it is possible to suppress the generation of fuel dilution and improve fuel economy by warming up the internal combustion engine in the early stage. Attached Figure Description

[0007] Hereinafter, with reference to the accompanying drawings, the features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described, in which the same reference numerals denote the same elements, and wherein:

[0008] Figure 1 This is a schematic diagram illustrating the structure of a control device and an engine controlled by the same control device in one embodiment.

[0009] Figure 2 It means Figure 1 The flowchart shows the processing circuit of the control device, which performs control based on oil temperature selection.

[0010] Figure 3 This indicates that in the first control... Figure 1 The flowchart shows the process performed by the processing circuit.

[0011] Figure 4 This indicates that in the second control... Figure 1 The flowchart shows the process performed by the processing circuit.

[0012] Figure 5 This is a flowchart illustrating the processing performed by the processing circuit of the control device in the first control step, representing a change example. Detailed Implementation

[0013] Structure of control device 10

[0014] The following is for reference. Figures 1 to 4 One embodiment of the control device 10 as a control device for an internal combustion engine will be described. For example... Figure 1 As shown, the control device 10 includes a processing circuit 11 and a storage device 12. The processing circuit 11 includes a CPU that executes processing according to a program and a ROM that stores the program. The storage device 12 includes a non-volatile memory that records data related to the engine 20.

[0015] Control device 10 is, for example, one of the control devices assembled into the engine electronic control unit (ECU) that controls the engine 20. Control device 10 controls the engine 20 based on information acquired by sensors located at various locations on the engine 20.

[0016] Structure of Engine 20

[0017] like Figure 1 As shown, engine 20 is a reciprocating engine with multiple cylinders 21B. Each cylinder 21B constitutes a combustion chamber for burning a mixture of fuel and intake air. The fuel in engine 20 is gasoline.

[0018] The engine 20 includes a cylinder block 21, a cylinder head 22, an intake manifold 29, and an exhaust manifold 33. The cylinder block 21 consists of a crankcase 21A and multiple cylinders 21B. Each cylinder 21B houses a piston 26A and a connecting rod 25. The connecting rod 25 is connected to a crankshaft 24 housed in the crankcase 21A.

[0019] A cylinder liner 23 is provided on the inner circumference of each cylinder 21B. A piston ring 26B is installed on the outer circumference of the piston 26A. The piston ring 26B, through sliding contact with the cylinder liner 23, suppresses leakage of the air-fuel mixture towards the crankcase 21A side, which is closer to the piston 26A than the piston 26A. The piston ring 26B, through sliding contact with the cylinder liner 23, scrapes excess lubricating oil adhering to the cylinder liner 23 onto the crankcase 21A side.

[0020] A cylinder head 22 is mounted on the upper part of each cylinder 21B. Each cylinder 21B and the cylinder head 22 constitute the combustion chamber of each cylinder 21B. The cylinder head 22 has an intake valve 30, an exhaust valve 32, an injector 31, and a camshaft 27 with multiple cams 28 fixed thereon. An intake passage 29 and an exhaust passage 33 communicating with each combustion chamber are respectively connected to the cylinder head 22.

[0021] The intake passage 29 is a channel for introducing external intake air into each combustion chamber. The downstream end of the intake passage 29 communicates with each combustion chamber. An intake valve 30 is provided at this end.

[0022] The exhaust passage 33 is a channel for guiding exhaust gas from each cylinder 21B into the exhaust system components. The upstream end of the exhaust passage 33 communicates with each combustion chamber. An exhaust valve 32 is provided at this end.

[0023] A camshaft 27 with multiple fixed cams 28 is respectively arranged on the upper part of the intake valve 30 and the exhaust valve 32. Each camshaft 27 is rotated by power transmission from the crankshaft 24. When each camshaft 27 rotates, the cam profile of the cam 28 presses down the intake valve 30 or exhaust valve 32 of each combustion chamber. When the cam 28 presses down the intake valve 30, the downstream end of the intake passage 29 in the combustion chamber is opened. During the period when the piston 26A descends and the end is opened as described above, intake air is introduced into the combustion chamber. When the cam 28 presses down the exhaust valve 32, the upstream end of the exhaust passage 33 in the combustion chamber is opened. During the period when the piston 26A rises and the end is opened as described above, exhaust air is discharged from the combustion chamber.

[0024] An injector 31 is inserted into the intake passage 29 side of the cylinder head 22. The engine 20 is a direct injection internal combustion engine. The front end of the injector 31 communicates with the combustion chamber. The injector 31 injects gasoline supplied from the fuel tank directly into the combustion chamber from the front end of the injector 31. The atomized gasoline injected from the injector 31 fills the combustion chamber.

[0025] Cooling system 70

[0026] exist Figure 1A portion of the cooling system 70 of the engine 20 is shown. The cooling system 70 cools the various components of the engine 20. The cooling system 70 includes a first cooling water passage 71, a second cooling water passage 72, a radiator 73, a water pump 74, and a water jacket (not shown). The water jacket is disposed inside the cylinder block 21. The water jacket is the flow path for the cooling water that cools the cylinder block 21. The cooling water flowing into the water jacket cools the walls of each cylinder 21B as it circulates within the water jacket.

[0027] The first cooling water passage 71 connects the radiator 73 and the water jacket. A water pump 74 is installed on the first cooling water passage 71. The water pump 74 draws in cooling water from the radiator 73 side and discharges it to the water jacket side. As the water pump 74 rotates and discharges cooling water, as shown by the arrow, the cooling water circulates in the flow path of the cooling system 70. That is, the first cooling water passage 71 is the flow path that supplies cooling water cooled by the radiator 73 to the cylinder block 21.

[0028] The second cooling water passage 72 connects the water jacket and the radiator 73. That is, the second cooling water passage 72 is the flow path for the cooling water that causes the temperature of the cylinder block 21 to rise back to the radiator 73.

[0029] Radiator 73 is a heat exchanger that reduces the temperature of cooling water through air cooling. Cooling water cooled by radiator 73 flows into the first cooling water path 71. A water temperature sensor 16 is installed on the second cooling water path 72. The water temperature sensor 16 measures the temperature of the cooling water. The water temperature sensor 16 is connected to the control device 10. The water temperature measured by the water temperature sensor 16 is input to the control device 10.

[0030] Lubrication system 50

[0031] exist Figure 1 The image shows the lubrication system 50 of the engine 20. The lubrication system 50 lubricates the various components of the engine 20. (Example...) Figure 1 As shown, the lubrication system 50 includes an oil pan 57, an intake port 58, an oil pump 61, an electric valve 62, a piston injector 63, and a cam sprayer 64. The lubrication system 50 has five lubricating oil supply paths: a first oil passage 51, a second oil passage 52, a third oil passage 53, a fourth oil passage 54, and a fifth oil passage 55. The first oil passage 51 is the main oil passage supplying lubricating oil to each of the second, third, fourth, and fifth oil passages 55. The second, third, fourth, and fifth oil passages 52, 53, 54, and 55 are branch oil passages supplying lubricating oil to the components of the engine 20.

[0032] An oil pump 61 is installed on the first oil passage 51. The oil pump 61 is a variable-capacity oil pump; that is, it is a variable-capacity oil pump capable of changing the unit output volume per revolution of the pump. The unit output volume is physically changed by altering the positions of the outer and inner rotors located inside the oil pump 61. The oil pump 61 is connected to a control device 10. The processing circuit 11 of the control device 10 controls the unit output volume of the oil pump 61.

[0033] Lubricating oil is stored in an oil pan 57 located at the bottom of the cylinder block 21. The lubricating oil is drawn in from the suction port 58 by the rotation of the oil pump 61 and flows into the first oil passage 51. As indicated by the arrow, the drawn-in lubricating oil flows in the first oil passage 51.

[0034] In the first oil passage 51, further downstream than the oil pump 61, a second oil passage 52 branches off from the first oil passage 51 to supply lubricating oil to the crankshaft 24. The second oil passage 52 is an oil passage that supplies lubricating oil to the bearings supporting the crankshaft 24 and the interior of the crankshaft 24.

[0035] A third oil passage 53, supplying lubricating oil to the piston injector 63, branches off from the first oil passage 51 further downstream than the branch of the second oil passage 52. The piston injector 63 sprays lubricating oil onto the back of the piston 26A. The lubricating oil sprayed from the piston injector 63 cools the piston 26A. The lubricating oil sprayed from the piston injector 63 indirectly cools the cylinder liner 23 by cooling the piston 26A. An electric valve 62 is located further upstream of the piston injector 63 in the third oil passage 53.

[0036] Electric valve 62 is a solenoid valve that controls the opening and closing of an electrically controlled valve. Solenoid valves differ from mechanical valves in that they can open and close the valve independently of oil pressure.

[0037] Mechanical valves open and close based on the oil pressure applied to them. A mechanical valve opens when the applied oil pressure is above a predetermined level and closes when the applied oil pressure is below the predetermined level. In other words, a mechanical valve blocks the flow of lubricating oil when the applied oil pressure is below the predetermined level.

[0038] The viscosity of lubricating oil increases as the oil temperature decreases. If the viscosity of the lubricating oil increases, it will be difficult for the lubricating oil to flow out from the various oil passages of the lubrication system 50, thereby causing the oil pressure in the lubrication system 50 to rise easily. In this case, even if the amount of lubricating oil discharged from the oil pump 61 is reduced, the oil pressure applied to the valve cannot be reduced to the oil pressure required for the mechanical valve to close. That is, if the valve located upstream of the piston injector 63 is a mechanical valve, the supply of lubricating oil to the piston injector 63 cannot be blocked when the oil temperature is low.

[0039] The electric valve 62 of the engine 20 is a solenoid valve that can open and close independently of oil pressure. Even at low oil temperatures, by closing the electric valve 62, the engine 20 can block the supply of lubricating oil to the piston injector 63. The electric valve 62 is connected to the control device 10. The processing circuit 11 of the control device 10 controls the opening and closing of the solenoid valve of the electric valve 62.

[0040] Further downstream from the branch of the third oil passage 53, the first oil passage 51 branches into two oil passages: the fourth oil passage 54 and the fifth oil passage 55. The fourth oil passage 54 supplies lubricating oil to the variable valve mechanism located at the end of the camshaft 27. The fifth oil passage 55 supplies lubricating oil to the cam sprayer 64. The cam sprayer 64 sprays lubricating oil from the upper part of the cam 28 and the camshaft 27.

[0041] In the lubrication system 50, lubricating oil is dispensed by the rotating oil pump 61 and circulates within the lubrication system 50. Through the aforementioned oil passages, lubricating oil is supplied to various components of the engine 20. Over time, the lubricating oil supplied to these components flows to the oil pan 57 and is stored there again.

[0042] When the electric valve 62 is closed, the supply of lubricating oil to the piston injector 63 is blocked. In this state, lubricating oil discharged from the oil pump 61 is supplied to the various components of the engine 20 through oil passages other than the third oil passage 53 in the lubrication system 50. Specifically, when the electric valve 62 is closed, lubricating oil is supplied to the various components of the engine 20 through the second oil passage 52, the fourth oil passage 54, and the fifth oil passage 55.

[0043] An oil temperature sensor 15 is installed upstream of the oil pump 61 in the first oil passage 51. The oil temperature sensor 15 measures the temperature of the lubricating oil. The oil temperature sensor 15 is connected to the control device 10. The oil temperature measured by the oil temperature sensor 15 is input to the control device 10.

[0044] Selection of control in lubricant supply

[0045] Figure 2 This is a flowchart illustrating the process of processing circuit 11 selecting and controlling the supply of lubricating oil based on oil temperature. Processing circuit 11 repeats this process at predetermined intervals, for example, starting from the start of engine 20. Figure 2 The processing.

[0046] like Figure 2 As shown, in S100, the processing circuit 11 acquires the oil temperature in the engine 20. The processing circuit 11 acquires the measured temperature of the oil temperature sensor 15 as input from the oil temperature sensor 15.

[0047] Next, in S110, the processing circuit 11 determines whether the acquired oil temperature is above a predetermined temperature. If the processing circuit 11 determines that the oil temperature is above the predetermined temperature (S110; "Yes"), the processing proceeds to S120. If the processing circuit 11 determines that the oil temperature is below the predetermined temperature (S110; "No"), the processing proceeds to S130. The predetermined temperature is, for example, the lowest temperature within the temperature range of the lubricating oil circulating in the engine 20 that sufficiently heats up to maintain good lubrication in the components of the engine 20.

[0048] In S120, the processing circuit 11 selects the second control as the control for supplying lubricating oil. The second control is the control performed by the processing circuit 11 when the oil temperature is above a predetermined temperature. The second control is the control performed by the processing circuit 11 after the lubricating oil in the engine 20 has been sufficiently heated. Details about the second control will be described later.

[0049] In S130, the processing circuit 11 selects the first control as the control for supplying lubricating oil. The first control is the control performed by the processing circuit 11 when the oil temperature is lower than a predetermined temperature. The first control is the control performed by the processing circuit 11 until the lubricating oil in the engine 20 is sufficiently heated. Details about the first control will be described later.

[0050] If the processing circuit 11 executes the processing in S120 or S130, the process will temporarily end. Figure 2 The process is illustrated in the series of steps shown. Thus, the processing circuit 11 switches the control of the lubricating oil supply based on the oil temperature.

[0051] Lubrication based on the first control

[0052] Figure 3 This is a flowchart illustrating the process of processing circuit 11 controlling the supply of lubricating oil based on lubrication system 50 in the first control. Processing circuit 11 in... Figure 2 The process shown repeats at predetermined intervals during the period selected by the first control. Figure 3 The processing shown.

[0053] In S200, the processing circuit 11 closes the electric valve 62. The processing circuit 11 blocks the supply of lubricating oil to the piston injector 63 by closing the electric valve 62. That is, in the first control, the injection of lubricating oil from the piston injector 63 is stopped.

[0054] Next, in S210, the processing circuit 11 maintains the state where the unit discharge volume of the oil pump 61 is maximized. Specifically, the processing circuit 11 aligns the positions of the outer rotor and inner rotor inside the oil pump 61 with the position where the unit discharge volume of the oil pump 61 is maximized. If the oil pump 61 rotates in this state, the maximum amount of lubricating oil is discharged from the oil pump 61.

[0055] If the processing circuit 11 executes the process in S210, then the process will temporarily end. Figure 3 The series of processes shown. The processing circuit 11 performs a first control when the oil temperature is lower than a predetermined temperature. In the first control, the processing circuit 11 performs the following processes: stops the injection of lubricating oil from the piston injector 63; and maximizes the unit output of the oil pump 61 during the period when the injection of lubricating oil from the piston injector 63 is stopped.

[0056] Lubrication based on the second control

[0057] Figure 4 This is a flowchart illustrating the process of processing circuit 11 controlling the supply of lubricating oil based on lubrication system 50 in the second control. Processing circuit 11 in... Figure 2 The process shown repeats at predetermined intervals during the second control period. Figure 4 The processing shown.

[0058] like Figure 4 As shown, in S300, the processing circuit 11 opens the electric valve 62. By opening the electric valve 62, the processing circuit 11 can supply lubricating oil to the piston injector 63 through the third oil passage 53. The piston injector 63 sprays the lubricating oil supplied through the third oil passage 53 onto the back of the piston 26A.

[0059] Next, in S310, the processing circuit 11 obtains the necessary oil pressure in each component of the engine 20. The necessary oil pressure represents the minimum amount of lubricating oil required at a given time for each component of the engine 20 to operate properly. If the necessary oil pressure is obtained, the processing circuit 11 proceeds to S320.

[0060] In S320, the processing circuit 11 calculates the required oil pressure based on the necessary oil pressure in each component. For example, the processing circuit 11 determines the largest necessary oil pressure among the necessary oil pressures in each component obtained in S310 as the required oil pressure. This required oil pressure is an oil pressure that changes constantly with the change in the necessary oil pressure in each component.

[0061] In S330, processing circuit 11 calculates the amount of lubricating oil discharged from oil pump 61 required to meet the required oil pressure, based on the required oil pressure calculated in S320. This discharge amount is referred to as the first discharge amount. If the first discharge amount is calculated, processing circuit 11 proceeds to S340.

[0062] In S340, the processing circuit 11 adjusts the unit discharge rate in the oil pump 61 based on the first discharge rate calculated in S330. Specifically, the processing circuit 11 calculates the target unit discharge rate based on the rotational speed of the oil pump 61 per unit time. Then, the processing circuit 11 aligns the positions of the outer and inner rotors inside the oil pump 61 with the positions corresponding to the target unit discharge rate. If the oil pump 61 rotates in this state, the first discharge rate of lubricating oil is discharged from the oil pump 61.

[0063] If the processing circuit 11 executes the processing of S340, then the process will temporarily end. Figure 4 The series of processes shown. The processing circuit 11 executes the second control when the oil temperature is above a predetermined temperature. In the second control, the processing circuit 11 performs the following processes: opening the electric valve 62 to allow lubricating oil to be injected from the piston injector 63; and controlling the unit discharge volume from the oil pump 61 to a unit discharge volume corresponding to the changing required oil pressure.

[0064] The function of this implementation method

[0065] In engine 20, if the injection of lubricating oil from piston injector 63 is stopped, the wall temperature of piston 26A and cylinder liner 23 is prone to rise. If the wall temperature of cylinder liner 23 rises, the fuel adhering to cylinder liner 23 is prone to volatilization. When the oil temperature is lower than a predetermined low temperature, processing circuit 11 closes electric valve 62 to stop the injection of lubricating oil from piston injector 63. In this way, processing circuit 11 reduces the amount of fuel adhering to cylinder liner 23 and scraped off by piston ring 26B and mixed into the lubricating oil.

[0066] However, if the injection of lubricating oil from the piston injector 63 is stopped, heat exchange between the lubricating oil and the piston 26A cannot occur, thus suppressing the temperature rise of the lubricating oil. Therefore, during the period when the oil temperature is below a predetermined temperature and the injection of lubricating oil from the piston injector 63 is stopped, the processing circuit 11 maximizes the unit output of lubricating oil from the oil pump 61. In this way, the processing circuit 11 promotes heat exchange caused by the contact between the various components of the engine 20 and the lubricating oil, replenishing the amount that cannot exchange heat with the piston 26A, thereby accelerating the temperature rise of the lubricating oil. If the viscosity of the lubricating oil decreases due to the temperature rise, the components of the engine 20 are properly lubricated, thus reducing power loss caused by friction.

[0067] Effects of this implementation method

[0068] (1) According to the control device 10, the engine 20 can be warmed up early to improve fuel economy while suppressing the generation of fuel dilution.

[0069] (2) When the oil temperature is lower than a predetermined temperature, the processing circuit 11 of the control device 10 maximizes the unit output from the oil pump 61. By maximizing the unit output, the processing circuit 11 maximizes the amount of lubricating oil that comes into contact with the components of the engine 20 per unit time.

[0070] The control device 10 can maximize heat exchange. (3) When the oil temperature is above a predetermined temperature, the processing circuit 11 of the control device 10 performs the following control. This control means opening the electric valve 62 to allow lubricating oil to be injected from the piston injector 63; and controlling the unit output of lubricating oil from the oil pump 61 to a unit output corresponding to the changing required oil pressure.

[0071] When the oil temperature is above a predetermined temperature, the processing circuit 11 sprays lubricating oil from the piston injector 63 to cool and lubricate the piston 26A. When the oil temperature is above the predetermined temperature, the processing circuit 11 controls the oil pump 61 according to the changing required oil pressure. Thus, the processing circuit 11 causes the oil pump 61 to operate at a load commensurate with the required oil pressure.

[0072] According to the control device 10, the oil pump 61 can be suppressed from running meaninglessly. (4) The processing circuit 11 of the control device 10 uses the measured temperature of the oil temperature sensor 15, which measures the temperature of the lubricating oil in the engine 20, as the oil temperature.

[0073] The control device 10 uses the oil temperature sensor 15 to directly obtain the oil temperature. Based on this oil temperature, the processing circuit 11 controls the opening and closing of the electric valve 62 and the amount of lubricating oil discharged from the oil pump 61.

[0074] Change Example

[0075] According to the control device 10, the supply of lubricating oil can be controlled based on the accurate oil temperature. This embodiment can be modified to be implemented in the following ways. This embodiment and the following modifications can be combined with each other within the scope of technical non-contradiction.

[0076] • When the oil temperature is below a predetermined temperature, the processing circuit 11 maximizes the unit discharge volume from the oil pump 61. The processing circuit 11 may also choose not to maximize the unit discharge volume from the oil pump 61. During periods when the injection of lubricating oil from the piston injector 63 is stopped, the processing circuit 11 maintains the unit discharge volume of lubricating oil from the oil pump 61 at a level sufficient to replenish the amount that cannot exchange heat with the piston 26A. The minimum value that can replenish the amount of lubricating oil that cannot exchange heat is a predetermined quantity. In other words, during periods when the injection of lubricating oil from the piston injector 63 is stopped, the processing circuit 11 maintains the unit discharge volume of lubricating oil from the oil pump 61 at a level sufficient to replenish the predetermined quantity.

[0077] Thus, the control device 10 of the modified example achieves the same effect as described in (1) above.

[0078] • The control device 10 described above can adjust the unit output of the oil pump 61 within a range above a predetermined amount to correspond to the required oil pressure when the oil temperature is lower than a predetermined temperature.

[0079] · Figure 5 This is a flowchart illustrating the process of the processing circuit 11, which applies the two modified examples described above, controlling the supply of lubricating oil based on the lubrication system 50 in the first control. The processing circuit 11 in... Figure 2 The process shown repeats at predetermined intervals during the period selected by the first control. Figure 5 The processing shown.

[0080] In S400, processing circuit 11 and Figure 3 Similarly, in S200, the electric valve 62 is closed. The processing circuit 11 stops the injection of lubricating oil from the piston injector 63 by closing the electric valve 62.

[0081] like Figure 5 As shown, in S410, the processing circuit 11 and Figure 4 Similarly, S310, as shown, obtains the necessary oil pressure in each component of the engine 20.

[0082] like Figure 5 As shown, in S420, processing circuit 11 and Figure 4 Similarly, the required oil pressure is calculated based on the necessary oil pressure in each component of the S320 shown.

[0083] like Figure 5 As shown, in S430, processing circuit 11 calculates a second discharge amount based on the required oil pressure in S420, which is the amount of lubricating oil discharged from oil pump 61 needed to meet the required oil pressure. The discharge amount of the second discharge amount is more than... Figure 4 The first discharge volume is large. The second discharge volume, for example, is a constant discharge volume added relative to the first discharge volume. The second discharge volume, like the first discharge volume, varies according to the required oil pressure.

[0084] like Figure 5 As shown, in S440, processing circuit 11 and Figure 4 Similarly, in S340, the unit discharge rate in oil pump 61 is changed. At this time, processing circuit 11 first calculates the unit discharge rate in oil pump 61 based on the second discharge rate calculated in S430. Then, processing circuit 11 compares the calculated unit discharge rate with the minimum discharge rate. The minimum discharge rate is the aforementioned predetermined amount. The minimum discharge rate is the minimum value of the unit discharge rate in oil pump 61 during the period when the injection of lubricating oil from piston injector 63 is stopped.

[0085] Processing circuit 11 determines the larger of the unit discharge amount calculated in S440 and the minimum discharge amount as the target unit discharge amount. Then, processing circuit 11 aligns the positions of the outer rotor and inner rotor inside oil pump 61 with the positions corresponding to the target unit discharge amount. If oil pump 61 rotates in this state, lubricating oil above the minimum discharge amount is discharged from oil pump 61.

[0086] If the processing circuit 11 finishes processing S440, then the process will temporarily end. Figure 5 The series of processes shown. Thus, when the oil temperature is below a predetermined temperature, the processing circuit 11 maintains the unit discharge amount of lubricating oil from the oil pump 61 above the minimum discharge amount during the period when the injection of lubricating oil from the piston injector 63 is stopped.

[0087] The processing circuit 11 uses the temperature measured by the oil temperature sensor 15 as the oil temperature. The processing circuit 11 can also estimate the oil temperature based on the temperature measured by the water temperature sensor 16, which measures the temperature of the coolant in the engine 20. Figure 2 In S100 shown, the oil temperature is obtained based on the water temperature estimate.

[0088] The processing circuit 11 estimates the oil temperature based on the temperature of the cooling water obtained using the water temperature sensor 16. Based on the estimated oil temperature, the processing circuit 11 controls the opening and closing of the electric valve 62 and the amount of lubricating oil discharged from the oil pump 61.

[0089] According to the control device 10 described above, the supply of lubricating oil can be controlled based on the temperature of the cooling water.

Claims

1. A control device for an internal combustion engine, comprising: a piston injector for injecting lubricating oil onto the back of a piston; and a variable oil pump for varying the amount of lubricating oil discharged per revolution, the control device being characterized in that it includes a processing circuit. The processing circuit performs the following processing: when the temperature of the lubricating oil is lower than a predetermined temperature, it closes the solenoid valve located on the lubricating oil supply path to the piston injector to stop the injection of lubricating oil from the piston injector; and during the period when the injection of lubricating oil from the piston injector is stopped, the amount of lubricating oil discharged from the variable oil pump is maintained above a predetermined amount.

2. The control device for an internal combustion engine according to claim 1, characterized in that, The processing circuit maximizes the discharge volume from the variable oil pump when the oil temperature is below a predetermined temperature.

3. The control device for an internal combustion engine according to claim 1 or 2, characterized in that, The processing circuit performs the following processing: when the oil temperature is above a predetermined temperature, it opens the solenoid valve to allow lubricating oil to be injected from the piston injector; and controls the discharge amount of lubricating oil from the variable oil pump to a discharge amount corresponding to the changing required oil pressure.

4. The control device for an internal combustion engine according to claim 1 or 2, characterized in that, The processing circuit uses the temperature measured by the oil temperature sensor, which measures the temperature of the lubricating oil in the internal combustion engine, as the oil temperature.

5. The control device for an internal combustion engine according to claim 1 or 2, characterized in that, The processing circuit estimates the oil temperature based on the temperature measured by a water temperature sensor that measures the temperature of the cooling water in the internal combustion engine.

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