Control device for internal combustion engines
The control device for internal combustion engines addresses fuel dilution by controlling lubricating oil injection and discharge to prevent fuel dilution and enhance engine warm-up and efficiency.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-12-18
- Publication Date
- 2026-06-30
Smart Images
Figure 2026106779000001_ABST
Abstract
Description
Technical Field
[0006] , , ,
[0005] , ,
[0001] This invention relates to a control device for an internal combustion engine.
Background Art
[0002] In an internal combustion engine, fuel may mix into the lubricating oil that lubricates the components of the internal combustion engine, resulting in fuel dilution. After fuel dilution occurs, if the fuel mixed in the lubricating oil volatilizes and the blow-by gas containing fuel is introduced into the intake system of the internal combustion engine, disturbances in the air-fuel ratio such as enrichment of the air-fuel mixture will be caused.
[0003] Patent Document 1 discloses a fuel dilution elimination device for eliminating fuel dilution when fuel dilution occurs. When it is determined that fuel dilution has occurred, this elimination device controls the internal combustion engine to operate at a higher speed to promote the volatilization of fuel, thereby quickly eliminating fuel dilution.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] The above fuel dilution elimination device can quickly eliminate the generated fuel dilution, but it cannot suppress the occurrence of fuel dilution itself.
Means for Solving the Problems
[0006] The control device for an internal combustion engine that solves the above problems controls an internal combustion engine equipped with a piston jet that injects lubricating oil onto the back surface of a piston and a variable oil pump that changes the amount of lubricating oil discharged per revolution. This control device for an internal combustion engine is equipped with a processing circuit. When the oil temperature, which is the temperature of the lubricating oil, falls below a predetermined temperature, the processing circuit of this control device for an internal combustion engine closes a solenoid valve provided in the supply passage for lubricating oil to the piston jet to stop the injection of lubricating oil from the piston jet. When the oil temperature, which is the temperature of the lubricating oil, falls below a predetermined temperature, the processing circuit of this control device for an internal combustion engine maintains the amount of lubricating oil discharged from the variable oil pump to be above a predetermined amount while the injection of lubricating oil from the piston jet is stopped. [Effects of the Invention]
[0007] According to the control device for the internal combustion engine described above, fuel dilution can be suppressed while the internal combustion engine can be warmed up quickly, thereby improving fuel efficiency. [Brief explanation of the drawing]
[0008] [Figure 1] Figure 1 is a schematic diagram showing the configuration of a control device and the engine controlled by the control device according to one embodiment. [Figure 2] Figure 2 is a flowchart showing the process by which the control circuit of the control device in Figure 1 selects the control to be executed based on the oil temperature. [Figure 3] Figure 3 is a flowchart showing the process executed by the processing circuit in Figure 1 during the first control phase. [Figure 4] Figure 4 is a flowchart showing the process executed by the processing circuit in Figure 1 during the second control phase. [Figure 5] Figure 5 is a flowchart showing the processing performed in the first control by the processing circuit of the modified control device. [Modes for carrying out the invention]
[0009] The control device 10, which is one embodiment of the control device for an internal combustion engine, will be described below with reference to Figures 1 to 4. <Configuration of the control device 10> As shown in Figure 1, the control device 10 comprises 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 in which the program is stored. The storage device 12 includes a non-volatile memory that records data related to the engine 20.
[0010] The control device 10 is, for example, one of the control devices incorporated into the engine ECU (Electronic Control Unit) that controls the engine 20. The control device 10 controls the engine 20 based on information acquired by sensors located at various points on the engine 20.
[0011] <Engine 20 Configuration> As shown in Figure 1, the engine 20 is a reciprocating engine having multiple cylinders 21B. Each cylinder 21B constitutes a combustion chamber for burning a mixture of fuel and intake air. The fuel in the engine 20 is gasoline.
[0012] The engine 20 comprises a cylinder block 21, a cylinder head 22, an intake passage 29, and an exhaust passage 33. The cylinder block 21 consists of a crankcase 21A and several cylinders 21B. Inside each cylinder 21B are a piston 26A and a connecting rod 25. The connecting rod 25 is connected to a crankshaft 24 housed in the crankcase 21A.
[0013] A cylinder liner 23 is provided on the inner circumference of each cylinder 21B. A piston ring 26B is fitted on the outer circumference of the piston 26A. The piston ring 26B slides against the cylinder liner 23, suppressing leakage of the fuel-air mixture towards the crankcase 21A side rather than the piston 26A side. The piston ring 26B also slides against the cylinder liner 23, scraping off excess lubricating oil adhering to the cylinder liner 23 towards the crankcase 21A side.
[0014] A cylinder head 22 is mounted above each cylinder 21B. Each cylinder 21B and the cylinder head 22 together constitute a combustion chamber for each cylinder 21B. The cylinder head 22 includes an intake valve 30, an exhaust valve 32, an injector 31, and a camshaft 27 to which multiple cams 28 are fixed. An intake passage 29 and an exhaust passage 33, which communicate with each combustion chamber, are connected to the cylinder head 22.
[0015] The intake passage 29 is a passage that introduces intake air from the outside into each combustion chamber. The downstream end of the intake passage 29 is connected to each combustion chamber. An intake valve 30 is provided at this end.
[0016] The exhaust passage 33 is a passage that introduces exhaust gas from each cylinder 21B to 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.
[0017] Above the intake valve 30 and the exhaust valve 32, a camshaft 27 to which a plurality of cams 28 are fixed is disposed respectively. Each camshaft 27 rotates upon receiving power transmission from the crankshaft 24. When each camshaft 27 rotates, the cam lobes of the cams 28 push down the intake valve 30 or the exhaust valve 32 of each combustion chamber. When the cam 28 pushes down the intake valve 30, the downstream end portion of the intake passage 29 in the combustion chamber is opened. While the piston 26A is descending and the end portion is opened as described above, intake air is introduced into the combustion chamber. When the cam 28 pushes down the exhaust valve 32, the upstream end portion of the exhaust passage 33 in the combustion chamber is opened. While the piston 26A is ascending and the end portion is opened as described above, exhaust gas is discharged from the combustion chamber.
[0018] An injector 31 is inserted on the intake passage 29 side of the cylinder head 22. The engine 20 is a direct injection type internal combustion engine. The tip of the injector 31 communicates with the combustion chamber. The injector 31 directly injects gasoline supplied from the fuel tank into the combustion chamber from the tip of the injector 31. The atomized gasoline injected from the injector 31 fills the combustion chamber.
[0019] <Cooling system 70> In FIG. 1, a part of the cooling system 70 of the engine 20 is shown. The cooling system 70 cools each component 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 provided inside the cylinder block 21. The water jacket is a flow path for cooling water that cools the cylinder block 21. The cooling water flowing into the water jacket cools the wall surfaces of each cylinder 21B while flowing through the water jacket.
[0020] The first cooling water passage 71 connects the radiator 73 and the water jacket. A water pump 74 is installed in the first cooling water passage 71. The water pump 74 discharges the cooling water sucked from the radiator 73 side to the water jacket side. As the water pump 74 rotates to discharge the cooling water, the cooling water circulates through the flow path of the cooling system 70 as indicated by the arrow. That is, the first cooling water passage 71 is a flow path that supplies the cooling water cooled by the radiator 73 to the cylinder block 21.
[0021] The second cooling water passage 72 connects the water jacket and the radiator 73. That is, the second cooling water passage 72 is a flow path that returns the cooling water whose temperature has risen by cooling the cylinder block 21 to the radiator 73.
[0022] The radiator 73 is a heat exchanger that lowers the temperature of the cooling water by an air-cooling method. The cooling water cooled by the radiator 73 flows into the first cooling water passage 71. A water temperature sensor 16 is installed in the second cooling water passage 72. The water temperature sensor 16 measures the water temperature, which is 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.
[0023] <Lubrication system 50> In FIG. 1, the lubrication system 50 of the engine 20 is shown. The lubrication system 50 lubricates each component of the engine 20. As shown in FIG. 1, the lubrication system 50 includes an oil pan 57, a suction port 58, an oil pump 61, an electric valve 62, a piston jet 63, and a cam shower 64. Five lubricating oil supply passages, namely 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, are provided in the lubrication system 50. The first oil passage 51 is a main oil passage that supplies lubricating oil to each of the second oil passage 52, the third oil passage 53, the fourth oil passage 54, and the fifth oil passage 55. The second oil passage 52, the third oil passage 53, the fourth oil passage 54, and the fifth oil passage 55 are oil passages branched to supply lubricating oil to the components of the engine 20, respectively.
[0024] An oil pump 61 is installed in the first oil passage 51. The oil pump 61 is a variable displacement oil pump. In other words, the oil pump 61 is a variable displacement oil pump that can change the unit discharge amount, which is the amount discharged per revolution of the pump. The oil pump 61 physically changes the unit discharge amount by changing the position of the outer rotor and inner rotor located inside the oil pump 61. The oil pump 61 is connected to the control device 10. The processing circuit 11 of the control device 10 controls the unit discharge amount in the oil pump 61.
[0025] Lubricating oil is stored in an oil pan 57 attached to the bottom of the cylinder block 21. This lubricating oil is drawn up from the intake port 58 by the rotation of the oil pump 61 and flows into the first oil passage 51. The drawn-up lubricating oil flows through the first oil passage 51 as indicated by the arrow.
[0026] Downstream of the oil pump 61 in the first oil passage 51, 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 to the inside of the crankshaft 24.
[0027] Downstream from the point where the second oil passage 52 branches off in the first oil passage 51, a third oil passage 53 branches off from the first oil passage 51 to supply lubricating oil to the piston jet 63. The piston jet 63 injects lubricating oil onto the back surface of the piston 26A. The lubricating oil injected from the piston jet 63 cools the piston 26A. By cooling the piston 26A, the lubricating oil injected from the piston jet 63 indirectly cools the cylinder liner 23. An electric valve 62 is installed upstream of the piston jet 63 in the third oil passage 53.
[0028] The electric valve 62 is a solenoid valve that electrically controls the opening and closing of the valve. Solenoid valves differ from mechanical valves in that they can open and close the valve regardless of hydraulic pressure. Mechanical valves open and close according to the hydraulic pressure applied to them. A mechanical valve opens when the hydraulic pressure is above a predetermined level. A mechanical valve closes when the hydraulic pressure is below a predetermined level. In other words, a mechanical valve shuts off the flow of lubricating oil when the hydraulic pressure is below a predetermined level.
[0029] The viscosity of lubricating oil increases as its temperature decreases. When the viscosity of the lubricating oil increases, it becomes more difficult for the lubricating oil to flow out of each oil passage in the lubrication system 50, which tends to increase the oil pressure in the lubrication system 50. In such cases, even if the amount of lubricating oil discharged from the oil pump 61 is reduced, the oil pressure on the valve cannot be reduced to the level at which the mechanical valve closes. In other words, if the valve installed upstream of the piston jet 63 is a mechanical valve, the supply of lubricating oil to the piston jet 63 cannot be shut off when the oil temperature is low.
[0030] The electric valve 62 of the engine 20 is a solenoid valve that can open and close regardless of the hydraulic pressure. Even when the oil temperature is low, the engine 20 can shut off the supply of lubricating oil to the piston jet 63 by closing the electric valve 62. 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.
[0031] Downstream from the point where the third oil passage 53 branches off in the first oil passage 51, the first oil passage 51 branches into two: the fourth oil passage 54 and the fifth oil passage 55. The fourth oil passage 54 is an oil passage that supplies lubricating oil to the variable valve mechanism located at the end of the camshaft 27. The fifth oil passage 55 is an oil passage that supplies lubricating oil to the cam shower 64. The cam shower 64 sprays lubricating oil from the top of the cam 28 and the camshaft 27.
[0032] In the lubrication system 50, the oil pump 61 rotates and discharges lubricating oil, causing the lubricating oil to circulate within the system. Lubricating oil is supplied to each component of the engine 20 via the oil passages described above. The lubricating oil supplied to each component flows down toward the oil pan 57 over time and is then stored in the oil pan 57 again.
[0033] When the electric valve 62 is closed, the supply of lubricating oil to the piston jet 63 is cut off. In this state, the lubricating oil discharged from the oil pump 61 is supplied to each component of the engine 20 through oil passages in the lubrication system 50 other than the third oil passage 53. Specifically, when the electric valve 62 is closed, lubricating oil is supplied to each component of the engine 20 through the second oil passage 52, the fourth oil passage 54, and the fifth oil passage 55.
[0034] 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 oil temperature, which is 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.
[0035] <Selection of control methods for lubricating oil supply> Figure 2 is a flowchart showing the process by which the processing circuit 11 selects a control for supplying lubricating oil based on the oil temperature. The processing circuit 11 repeatedly executes the process shown in Figure 2 at predetermined time intervals, for example, from the time the engine 20 is started.
[0036] As shown in Figure 2, in step S100, the processing circuit 11 acquires the oil temperature in the engine 20. The processing circuit 11 acquires the temperature measured by the oil temperature sensor 15, which is input from the oil temperature sensor 15, as the oil temperature.
[0037] Next, in step 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 a predetermined temperature (step S110; YES), it proceeds to step S120. If the processing circuit 11 determines that the oil temperature is below a predetermined temperature (step S110; NO), it proceeds to step S130. The predetermined temperature is, for example, the lowest temperature within the range of lubricating oil temperatures in which the lubricating oil circulating in the engine 20 is sufficiently warmed and the lubrication state of the components of the engine 20 is maintained in good condition.
[0038] In step S120, the processing circuit 11 selects a second control as the control for supplying lubricating oil. The second control is performed by the processing circuit 11 when the oil temperature is above a predetermined temperature. The second control is performed by the processing circuit 11 after the lubricating oil that lubricates the engine 20 has warmed up sufficiently. Details of the second control will be described later.
[0039] In step S130, the processing circuit 11 selects a first control as the control for supplying lubricating oil. The first control is a control performed by the processing circuit 11 when the oil temperature is below a predetermined temperature. The first control is a control performed by the processing circuit 11 until the lubricating oil that lubricates the engine 20 is sufficiently warmed up. Details of the first control will be described later.
[0040] As described above, once the processing circuit 11 has executed the process in step S120 or step S130, it terminates the series of processes shown in Figure 2. In this way, the processing circuit 11 switches the control of supplying lubricating oil according to the oil temperature.
[0041] <Lubrication by first control> Figure 3 is a flowchart showing the process by which the processing circuit 11 controls the supply of lubricating oil by the lubrication system 50 in the first control. While the first control is selected in the process shown in Figure 2, the processing circuit 11 repeatedly executes the process shown in Figure 3 at predetermined intervals.
[0042] In step S200, the processing circuit 11 closes the electric valve 62. By closing the electric valve 62, the processing circuit 11 cuts off the supply of lubricating oil to the piston jet 63. In other words, in the first control, the injection of lubricating oil from the piston jet 63 is stopped.
[0043] Next, in step S210, the processing circuit 11 maintains the maximum unit discharge rate of the oil pump 61. Specifically, the processing circuit 11 keeps the positions of the outer rotor and inner rotor inside the oil pump 61 aligned to the position where the unit discharge rate of the oil pump 61 is maximized. When the oil pump 61 rotates in this state, the maximum amount of lubricating oil is discharged from the oil pump 61.
[0044] As described above, once the processing circuit 11 has executed the process in step S210, it terminates the series of processes shown in Figure 3. The processing circuit 11 performs a first control that, when the oil temperature is below a predetermined temperature, stops the injection of lubricating oil from the piston jet 63, and maximizes the unit discharge amount from the oil pump 61 while the injection of lubricating oil from the piston jet 63 is stopped.
[0045] <Lubrication by second control> Figure 4 is a flowchart showing the process by which the processing circuit 11 controls the supply of lubricating oil by the lubrication system 50 in the second control. While the second control is selected in the process shown in Figure 2, the processing circuit 11 repeatedly executes the process shown in Figure 4 at predetermined intervals.
[0046] As shown in Figure 4, in step S300, the processing circuit 11 opens the electric valve 62. By opening the electric valve 62, the processing circuit 11 enables the supply of lubricating oil to the piston jet 63 through the third oil passage 53. The piston jet 63 injects the lubricating oil supplied through the third oil passage 53 onto the back surface of the piston 26A.
[0047] Next, in step S310, the processing circuit 11 obtains the required oil pressure for each component of the engine 20. The required oil pressure indicates the minimum amount of lubricating oil necessary for each component of the engine 20 to operate properly at a given point in time. Once the required oil pressure is obtained, the processing circuit 11 proceeds to step S320.
[0048] In step S320, the processing circuit 11 calculates the required hydraulic pressure based on the required hydraulic pressure of each component. For example, the processing circuit 11 determines the largest required hydraulic pressure among the required hydraulic pressures of each component obtained in step S310 as the required hydraulic pressure. This required hydraulic pressure is a hydraulic pressure that fluctuates moment by moment in accordance with the fluctuations in the required hydraulic pressure of each component.
[0049] In step S330, the processing circuit 11 calculates the amount of lubricating oil to be discharged from the oil pump 61 necessary to satisfy the required hydraulic pressure, based on the required hydraulic pressure calculated in step S320. This discharge amount is referred to as the first discharge amount. Once the first discharge amount is calculated, the processing circuit 11 proceeds to step S340.
[0050] In step S340, the processing circuit 11 changes the unit discharge rate of the oil pump 61 to match the first discharge rate calculated in step S330. Specifically, the processing circuit 11 calculates a target unit discharge rate according to the rotational speed of the oil pump 61 per unit time. Then, the processing circuit 11 adjusts the positions of the outer rotor and inner rotor inside the oil pump 61 to positions corresponding to the target unit discharge rate. As the oil pump 61 rotates in this state, the first discharge rate of lubricating oil is discharged from the oil pump 61.
[0051] As described above, once the processing circuit 11 has executed the process in step S340, it terminates the series of processes shown in Figure 4. The processing circuit 11 performs a second control, which, when the oil temperature is above a predetermined temperature, opens the electric valve 62 to inject lubricating oil from the piston jet 63 and controls the unit discharge amount from the oil pump 61 to a unit discharge amount corresponding to the fluctuating required oil pressure.
[0052] <Operation of this embodiment> In engine 20, stopping the injection of lubricating oil from piston jet 63 makes it easier for the wall temperatures of piston 26A and cylinder liner 23 to rise. When the wall temperature of cylinder liner 23 rises, fuel adhering to cylinder liner 23 is more likely to volatilize. When the oil temperature is below a predetermined temperature, the processing circuit 11 closes the electric valve 62 to stop the injection of lubricating oil from piston jet 63. In this way, the processing circuit 11 reduces the amount of fuel that adheres to cylinder liner 23, is scraped off by piston ring 26B, and mixes with the lubricating oil.
[0053] However, if the injection of lubricating oil from the piston jet 63 is stopped, heat exchange between the lubricating oil and the piston 26A ceases, thus suppressing the rise in the temperature of the lubricating oil. Therefore, the processing circuit 11 maximizes the unit discharge amount of lubricating oil from the oil pump 61 while the oil temperature is below a predetermined temperature and the injection of lubricating oil from the piston jet 63 is stopped. In this way, the processing circuit 11 promotes heat exchange through contact between each component of the engine 20 and the lubricating oil, compensating for the loss of heat exchange with the piston 26A and accelerating the rise in the temperature of the lubricating oil. As the viscosity of the lubricating oil decreases due to the rise in temperature, the components of the engine 20 are properly lubricated, thus reducing power loss due to friction.
[0054] <Effects of this embodiment> (1) The control device 10 can improve fuel efficiency by warming up the engine 20 earlier while suppressing the occurrence of fuel dilution.
[0055] (2) When the oil temperature is below a predetermined temperature, the processing circuit 11 of the control device 10 maximizes the unit discharge amount from the oil pump 61. The processing circuit 11 maximizes the amount of lubricating oil that comes into contact with the components of the engine 20 per unit time by maximizing the unit discharge rate.
[0056] 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 opens the electric valve 62 to inject lubricating oil from the piston jet 63 and controls the unit discharge amount of lubricating oil from the oil pump 61 to a unit discharge amount corresponding to the fluctuating required oil pressure.
[0057] When the oil temperature is above a predetermined temperature, the processing circuit 11 injects lubricating oil from the piston jet 63 to cool and lubricate the piston 26A. When the oil temperature is above a predetermined temperature, the processing circuit 11 controls the oil pump 61 according to the fluctuating required oil pressure. In this way, the processing circuit 11 operates the oil pump 61 with a load that matches the required oil pressure.
[0058] The control device 10 can prevent the oil pump 61 from operating unnecessarily. (4) The processing circuit 11 of the control device 10 uses the temperature measured by the oil temperature sensor 15, which measures the temperature of the lubricating oil provided in the engine 20, as the oil temperature.
[0059] The control device 10 directly obtains the oil temperature using the oil temperature sensor 15. 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.
[0060] According to the control device 10, the supply of lubricating oil can be controlled based on the precise oil temperature. <Example of changes> This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.
[0061] The processing circuit 11 maximizes the unit discharge rate from the oil pump 61 when the oil temperature is below a predetermined temperature. The processing circuit 11 does not have to maximize the unit discharge rate from the oil pump 61. While the injection of lubricating oil from the piston jet 63 is stopped, the processing circuit 11 only needs to maintain the unit discharge rate of lubricating oil discharged from the oil pump 61 at or above a unit discharge rate that can compensate for the loss of heat exchange with the piston 26A. The minimum value of this unit discharge rate that can compensate for the loss of heat exchange is the predetermined amount. In other words, while the injection of lubricating oil from the piston jet 63 is stopped, the processing circuit 11 only needs to maintain the unit discharge rate of lubricating oil discharged from the oil pump 61 at or above a predetermined amount.
[0062] Thus, the modified control device 10 achieves the same effect as (1) above. The control device 10 described above may, when the oil temperature is below a predetermined temperature, vary the unit discharge amount from the oil pump 61 within a range greater than or equal to the predetermined amount to match the required oil pressure.
[0063] Figure 5 is a flowchart showing the process by which the processing circuit 11, to which the two modified examples described above are applied, controls the supply of lubricating oil by the lubrication system 50 in the first control. While the first control is selected in the process shown in Figure 2, the processing circuit 11 repeatedly executes the process shown in Figure 5 at predetermined intervals.
[0064] In step S400, the processing circuit 11 closes the electric valve 62, similar to step S200 shown in Figure 3. By closing the electric valve 62, the processing circuit 11 stops the injection of lubricating oil from the piston jet 63.
[0065] As shown in Figure 5, in step S410, the processing circuit 11 obtains the required hydraulic pressure at each component of the engine 20, similar to step S310 shown in Figure 4. As shown in Figure 5, in step S420, the processing circuit 11 calculates the required hydraulic pressure based on the required hydraulic pressure of each component, similar to step S320 shown in Figure 4.
[0066] As shown in Figure 5, in step S430, the processing circuit 11 calculates a second discharge amount as the amount of lubricating oil to be discharged from the oil pump 61 necessary to satisfy the required hydraulic pressure, based on the required hydraulic pressure in step S420. The second discharge amount is larger than the first discharge amount in Figure 4. For example, the second discharge amount is the first discharge amount plus a certain amount. The second discharge amount, like the first discharge amount, fluctuates according to the required hydraulic pressure.
[0067] As shown in Figure 5, in step S440, the processing circuit 11 changes the unit discharge rate of the oil pump 61, similar to step S340 shown in Figure 4. At this time, the processing circuit 11 first calculates the unit discharge rate of the oil pump 61 in accordance with the second discharge rate calculated in step S430. Then, the processing circuit 11 compares the calculated unit discharge rate with the minimum discharge rate. The minimum discharge rate is the predetermined rate mentioned above. The minimum discharge rate is the minimum value of the unit discharge rate of the oil pump 61 while the injection of lubricating oil from the piston jet 63 is stopped.
[0068] The processing circuit 11 determines the target unit discharge amount to be the larger of the unit discharge amount and the minimum discharge amount calculated in step S440. Then, the processing circuit 11 adjusts the positions of the outer rotor and inner rotor inside the oil pump 61 to the position corresponding to the target unit discharge amount. As the oil pump 61 rotates in this state, lubricating oil at or above the minimum discharge amount is discharged from the oil pump 61.
[0069] As described above, once the processing circuit 11 has completed the processing in step S440, it temporarily terminates the series of processes shown in Figure 5. In this way, when the oil temperature is below a predetermined temperature, the processing circuit 11 stops the injection of lubricating oil from the piston jet 63, while maintaining the unit discharge amount of lubricating oil discharged from the oil pump 61 at or above the minimum discharge amount.
[0070] The processing circuit 11 uses the temperature measured by the oil temperature sensor 15 as the oil temperature. The processing circuit 11 may also estimate the oil temperature based on the temperature measured by the water temperature sensor 16, which measures the temperature of the coolant provided in the engine 20. In step S100 shown in Figure 2, the processing circuit 11 may acquire the oil temperature estimated based on the water temperature as the oil temperature.
[0071] The processing circuit 11 estimates the oil temperature based on the coolant temperature 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.
[0072] According to the control device 10 described above, the supply of lubricating oil can be controlled based on the temperature of the cooling water. [Explanation of symbols]
[0073] 10...Control device, 11...Processing circuit, 12...Memory device, 15...Oil temperature sensor, 16...Water temperature sensor, 20...Engine, 23...Cylinder liner, 26A...Piston, 26B...Piston ring, 51...First oil passage, 52...Second oil passage, 53...Third oil passage, 54...Fourth oil passage, 55...Fifth oil passage, 61...Oil pump, 62...Electric valve, 63...Piston jet, 64...Cam shower
Claims
1. A control device for an internal combustion engine, comprising a piston jet that injects lubricating oil onto the back surface of a piston, and a variable oil pump that changes the amount of lubricating oil discharged per revolution, Equipped with a processing circuit, The processing circuit performs the following actions when the oil temperature, which is the temperature of the lubricating oil, falls below a predetermined temperature: close a solenoid valve provided in the supply passage for lubricating oil to the piston jet to stop the injection of lubricating oil from the piston jet; and while the injection of lubricating oil from the piston jet is stopped, maintain the amount of lubricating oil discharged from the variable oil pump at or above a predetermined amount. Control device for internal combustion engines.
2. The aforementioned processing circuit is When the oil temperature is below a predetermined temperature, the discharge amount from the variable oil pump is maximized. A control device for an internal combustion engine according to claim 1.
3. The aforementioned processing circuit is When the oil temperature is above a predetermined temperature, the solenoid valve is opened to inject lubricating oil from the piston jet, and the discharge amount of lubricating oil from the variable oil pump is controlled to the discharge amount corresponding to the fluctuating required oil pressure. A control device for an internal combustion engine according to claim 1 or claim 2.
4. The processing circuit uses the temperature measured by the oil temperature sensor, which measures the temperature of the lubricating oil provided in the internal combustion engine, as the oil temperature. A control device for an internal combustion engine according to claim 1 or claim 2.
5. The processing circuit estimates the oil temperature based on the temperature measured by a water temperature sensor that measures the temperature of the coolant provided in the internal combustion engine. A control device for an internal combustion engine according to claim 1 or claim 2.