Internal combustion engine control device

Abstract

To suppress generation of striking sounds when an engine starts.SOLUTION: A control device 100, which is applied to a vehicle having an internal combustion engine 1 provided with a hydraulic intake-side rush adjuster 20 and an exhaust-side rush adjuster 23 to which lubricant is supplied during driving an engine, in a valve system, and a vehicle driving motor, performs a calculation processing and a start processing when travelling by the motor while stopping the internal combustion engine 1. The calculation processing calculates a lubricant amount in the intake-side rush adjuster 20 and a lubricant amount in the exhaust-side rush adjuster 23 on the basis of the time when a crank angle of the internal combustion engine 1 becomes a value within a prescribed range and a temperature of the lubricant supplied to the intake-side rush adjuster 20 and the exhaust-side rush adjuster 23. The start processing starts the internal combustion engine 1 when the calculated lubricant amount is equal to or lower than a prescribed threshold value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for an internal combustion engine. [Background technology]

[0002] As described in Patent Document 1, a valve train of an internal combustion engine is provided with a hydraulic lash adjuster to which lubricating oil is supplied while the engine is operating. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-167891 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a hybrid vehicle having an internal combustion engine and a motor for driving the vehicle, the internal combustion engine is stopped and the vehicle is driven by the motor in EV driving. During EV driving, lubricating oil may leak from the lash adjuster. If the holding force of the lash adjuster is reduced due to the leakage of lubricating oil from the lash adjuster, a gap may occur between the cam lobe and the rocker arm, which may cause a slapping noise when the engine is started. [Means for solving the problem]

[0005] A control device for an internal combustion engine that solves the above problems is applied to a vehicle having an internal combustion engine equipped in a valve train with a hydraulic lash adjuster to which lubricating oil is supplied during engine operation, and a motor for driving the vehicle. This control device performs a calculation process and a start process when the internal combustion engine is stopped and the vehicle is running using the motor. The calculation process is a process of calculating the amount of lubricating oil in the lash adjuster based on the time when the crank angle of the internal combustion engine is within a predetermined range and the temperature of the lubricating oil supplied to the lash adjuster, and the start process is a process of starting the internal combustion engine when the calculated amount of lubricating oil is equal to or less than a predetermined threshold value. Effect of the Invention

[0006] According to the present invention, the occurrence of hitting noises at engine start-up can be suppressed. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing a configuration of an internal combustion engine, a drive system, and a control device according to an embodiment; [Diagram 2] 4 is a flowchart showing the procedure of a process executed by the control device of the embodiment. [Diagram 3] FIG. 4 is a diagram showing the relationship between the valve lift amount and the leakage period. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of a control device for an internal combustion engine will be described with reference to the drawings. <Configuration of the internal combustion engine, drive system, and control device> As shown in Fig. 1, in an internal combustion engine 1, air is drawn into a combustion chamber 2 through an intake passage 3 and an intake port 3a, and fuel injected from a fuel injection valve 4 is supplied to the combustion chamber 2. When an air-fuel mixture made up of air and fuel is ignited by an ignition plug 5, the mixture is burned, causing a piston 6 to move back and forth, and rotating a crankshaft 7, which is an output shaft of the internal combustion engine 1. The burned air-fuel mixture is discharged from the combustion chamber 2 to an exhaust passage 8 as exhaust gas. A mechanical oil pump 70 that pressure-feeds lubricating oil to each part of the internal combustion engine 1 is connected to the crankshaft 7.

[0009] A throttle valve 29 for adjusting the amount of intake air is provided in the intake passage 3 of the internal combustion engine 1. The opening degree of this throttle valve 29 is adjusted by an electric motor. An intake valve 9 is provided in an intake port 3a connected to the intake passage 3. An exhaust valve 10 is provided in an exhaust port 8a connected to the exhaust passage 8. The intake valve 9 and the exhaust valve 10 open and close in accordance with the rotation of an intake camshaft 11 and an exhaust camshaft 12, to which the rotation of the crankshaft 7 is transmitted.

[0010] The intake valve 9 is biased in the valve closing direction by an intake valve spring 40. A rocker arm 19 is provided between the cam lobe of the intake camshaft 11 and the intake valve 9. When the cam lobe presses the rocker arm 19, the rocker arm 19 swings about a contact point with a hydraulic intake side lash adjuster 20 that supports one end of the rocker arm 19, and presses the intake valve 9 against the reaction force of the intake valve spring 40. The intake valve 9 is opened and closed by the pressing of the intake valve 9 by the rocker arm 19 and the reaction force of the intake valve spring 40. Lubricating oil pumped by an oil pump 70 is supplied to the intake side lash adjuster 20 provided in the valve train of the internal combustion engine 1.

[0011] The exhaust valve 10 is biased in the valve closing direction by an exhaust valve spring 41. A rocker arm 22 is provided between the cam lobe of the exhaust camshaft 12 and the exhaust valve 10. When the cam lobe presses the rocker arm 22, the rocker arm 22 swings about the point of contact with a hydraulic exhaust-side lash adjuster 23 that supports one end of the rocker arm 22, and presses the exhaust valve 10 against the reaction force of the exhaust valve spring 41. The exhaust valve 10 is opened and closed by the pressing of the exhaust valve 10 by the rocker arm 22 and the reaction force of the exhaust valve spring 41. Lubricating oil pumped by an oil pump 70 is supplied to the exhaust-side lash adjuster 23 provided in the valve train of the internal combustion engine 1.

[0012] The intake camshaft 11 is provided with an intake-side variable valve train 13 that changes the valve timing of the intake valve 9 by changing the relative phase of the intake camshaft 11 with respect to the crankshaft 7. The intake-side variable valve train 13 changes the valve timing of the intake valve 9 through the operation of an intake-side oil control valve 14 that is duty-controlled, for example.

[0013] The exhaust camshaft 12 is provided with an exhaust-side variable valve train 16 that changes the valve timing of the exhaust valve 10 by changing the relative phase of the exhaust camshaft 12 with respect to the crankshaft 7. The exhaust-side variable valve train 16 also changes the valve timing of the exhaust valve 10 through the operation of an exhaust-side oil control valve 17 that is duty-controlled, for example.

[0014] The crankshaft 7 is mechanically connected to a carrier C of a planetary gear mechanism 50 constituting a power split device. A rotating shaft 52a of a first motor generator 52 is mechanically connected to a sun gear S of the planetary gear mechanism 50. A rotating shaft 54a of a second motor generator 54 and a driving wheel 60 are mechanically connected to a ring gear R of the planetary gear mechanism 50. An AC voltage is applied to terminals of the first motor generator 52 by an inverter 56. An AC voltage is applied to terminals of the second motor generator 54 by an inverter 58.

[0015] The control device 100 operates the operation parts of the internal combustion engine 1, such as the throttle valve 29, the fuel injector 4, the spark plug 5, the intake side variable valve train 13, and the exhaust side variable valve train 16, to control the torque and the exhaust component ratio as the controlled variable of the internal combustion engine 1. The control device 100 also operates the first motor generator 52 as the controlled variable, and operates the inverter 56 to control the rotation speed as the controlled variable of the first motor generator 52. The control device 100 also operates the second motor generator 54 as the controlled variable, and operates the inverter 58 to control the torque as the controlled variable of the second motor generator 54. FIG. 1 shows operation signals MS1 to MS7 of the throttle valve 29, the fuel injector 4, the spark plug 5, the intake side variable valve train 13, the exhaust side variable valve train 16, and the inverters 56 and 58.

[0016] The control device 100 includes a CPU 120 and a memory 130 including a ROM, a RAM, and the like, and the CPU 120 executes programs stored in the memory 130 to thereby perform various types of control.

[0017] When performing various controls, the control device 100 refers to the intake air amount GA detected by the air flow meter 31 and the throttle opening TA, which is the opening of the throttle valve 29 detected by the throttle sensor 30. The control device 100 also refers to the cooling water temperature THW detected by the water temperature sensor 33 and the engine rotation speed NE calculated from the output signal Scr of the crank angle sensor 34. The control device 100 also refers to the output signal Scai of the intake side cam angle sensor 35, which detects the rotation angle of the intake camshaft 11, and the output signal Scae of the exhaust side cam angle sensor 36, which detects the rotation angle of the exhaust camshaft 12. The control device 100 also refers to the oil temperature THO, which is the temperature of the lubricating oil, detected by the oil temperature sensor 38. The control device 100 also refers to the output signal of the accelerator position sensor 28, which detects the accelerator operation amount ACCP, which is the operation amount of the accelerator pedal 27 operated by the driver of the vehicle equipped with the internal combustion engine 1. The control device 100 also refers to an output signal Sp of an output side rotation angle sensor 89 that detects the rotation angle of the ring gear R. The control device 100 also refers to an output signal Sm1 of a first rotation angle sensor 90 that detects the rotation angle of the first motor generator 52, in order to control the control amount of the first motor generator 52. The control device 100 also refers to an output signal Sm2 of a second rotation angle sensor 92 that detects the rotation angle of the second motor generator 54, in order to control the control amount of the second motor generator 54.

[0018] The control device 100 calculates the required torque required for the vehicle to travel based on the accelerator operation amount ACCP and the vehicle speed SP calculated from the output signal Sp. Then, the control device 100 controls the required output Pe of the internal combustion engine 1 and the output torque of the first motor generator 52 and the second motor generator 54 so as to satisfy the required torque of the vehicle. For example, when the required output Pe of the internal combustion engine 1 is "0", the operation of the internal combustion engine 1 is stopped and EV traveling is performed in which the vehicle travels using the output torque of the second motor generator 54.

[0019] <Processing performed by the control device> During acceleration and deceleration in EV driving, the crankshaft 7 may rotate temporarily, albeit at a small angle. When the crankshaft 7 rotates, the intake side lash adjuster 20 is pressed, causing lubricating oil to leak from the intake side lash adjuster 20. Here, a sufficient amount of lubricating oil is supplied to the intake side lash adjuster 20 while the internal combustion engine 1 is in operation, but when the crankshaft 7 rotates temporarily at a small angle, a sufficient amount of lubricating oil cannot be supplied to the intake side lash adjuster 20. Therefore, every time the crankshaft 7 rotates temporarily at a small angle during acceleration and deceleration in EV driving, the amount of lubricating oil in the intake side lash adjuster 20 decreases. When the amount of lubricating oil in the intake side lash adjuster 20 decreases beyond the allowable amount, the holding force of the intake side lash adjuster 20 decreases, causing a gap between the cam lobe and the rocker arm 19. Therefore, there is a risk of a banging sound being generated when the engine is started. Therefore, the control device 100 executes the following process to suppress the generation of such a banging sound.

[0020] 2 shows the procedure of the process executed at each predetermined cycle by the control device 100. In the following, the step number of each process is represented by a number preceded by the letter "S." When the series of processes shown in FIG. 2 is started, the control device 100 determines whether or not the vehicle is currently running in EV mode (S100).

[0021] When it is determined that the vehicle is in EV driving mode (S100: YES), the control device 100 executes a process for calculating the intake side oil amount OVi and the exhaust side oil amount OBe (S110). The intake-side oil amount OVi is the amount of lubricating oil in the intake-side lash adjuster 20, and the exhaust-side oil amount OBe is the amount of lubricating oil in the exhaust-side lash adjuster .

[0022] The control device 100 calculates the intake side oil amount OVi and the exhaust side oil amount OBe as follows. 3 shows the relationship between the valve lift amount and the leakage period of the intake valve 9 and the exhaust valve 10. The leakage period is the period during which lubricating oil leaks from the lash adjuster due to pressure from the cam lobe, and below, the leakage period of the intake side lash adjuster 20 will be referred to as the intake side leakage period LPi, and the leakage period of the exhaust side lash adjuster 23 will be referred to as the exhaust side leakage period LPe.

[0023] As shown in FIG. 3, the intake side leakage period LPi is a period within a predetermined range near the crank angle at which the valve lift amount of the intake valve 9 is maximum, and is variably set in accordance with changes in the valve timing of the intake valve 9.

[0024] There is a positive correlation between the intake side integrated time ITi, which is the integrated value of the time during which the crank angle of the crankshaft 7 is within the intake side leakage period LPi, and the intake side leakage amount Li, which is the amount of lubricating oil that has leaked from the intake side lash adjuster 20. In addition, the amount of lubricating oil that leaks from the intake side lash adjuster 20 is affected by the oil temperature THO, which is related to the viscosity of the lubricating oil.

[0025] Therefore, the control device 100 calculates the intake side integrated time ITi during EV driving. Then, the control device 100 calculates the intake side leakage amount Li based on the intake side integrated time ITi and the oil temperature THO. Then, the control device 100 calculates the intake side oil amount OVi by substituting a value obtained by subtracting the intake side leakage amount Li from the volume of the oil chamber of the intake side lash adjuster 20 into the intake side oil amount OVi. Note that the volume of the oil chamber of the intake side lash adjuster 20 is a known fixed value.

[0026] Similarly, the exhaust side leakage period LPe is a period within a predetermined range near the crank angle at which the valve lift amount of the exhaust valve 10 is maximum, and is variably set in accordance with changes in the valve timing of the exhaust valve 10.

[0027] There is a positive correlation between the exhaust-side accumulated time ITe, which is the accumulated value of the time that the crank angle of the crankshaft 7 is within the exhaust-side leakage period LPe, and the exhaust-side leakage amount Le, which is the amount of lubricating oil that has leaked from the exhaust-side lash adjuster 23. In addition, the amount of lubricating oil that leaks from the exhaust-side lash adjuster 23 is affected by the oil temperature THO, which is related to the viscosity of the lubricating oil.

[0028] Therefore, the control device 100 calculates the exhaust side integrated time ITe during EV driving. Then, the control device 100 calculates the exhaust side leakage amount Le based on the exhaust side integrated time ITi and the oil temperature THO. Then, the control device 100 calculates the exhaust side oil amount OVe by substituting a value obtained by subtracting the exhaust side leakage amount Le from the volume of the oil chamber of the exhaust side lash adjuster 23 into the exhaust side oil amount OVe. The volume of the oil chamber of the exhaust side lash adjuster 23 is also a known fixed value.

[0029] When the intake oil amount OVi and the exhaust oil amount OBe are calculated in the process of S110, the control device 100 executes the process of S120. In the process of S120, the control device 100 determines whether the intake-side oil amount OVi is equal to or less than a threshold value OViref or whether the exhaust-side oil amount OBe is equal to or less than a threshold value OVeref. The threshold value OViref is, for example, the minimum oil amount in the intake-side lash adjuster 20 that can suppress the occurrence of the above-mentioned hitting sound. Moreover, the threshold value OVeref is, for example, the minimum oil amount in the exhaust-side lash adjuster 23 that can suppress the occurrence of the above-mentioned hitting sound.

[0030] Then, when it is determined that the intake side oil amount OVi is equal to or less than the threshold value OViref, or the exhaust side oil amount OBe is equal to or less than the threshold value OVeref (S120: YES), the control device 100 executes the process of S130.

[0031] In the process of S130, the control device 100 executes a start process for starting the internal combustion engine 1 that is stopped during EV running. Then, when the process of S130 is completed, or when a negative determination is made in the process of S100 or the process of S120, the control device 100 ends the execution of this process in the current execution cycle.

[0032] <Actions and Effects of the Present Embodiment> According to this embodiment, when the intake-side oil amount OVi of the intake-side lash adjuster 20 falls to or below the threshold value OViref during EV driving, the internal combustion engine 1 is started, and lubricating oil is supplied to the intake-side lash adjuster 20. Therefore, the generation of hitting noises at engine start-up caused by a lack of lubricating oil in the intake-side lash adjuster 20 can be suppressed.

[0033] Furthermore, when the exhaust-side oil amount OVe in the exhaust-side lash adjuster 23 falls below the threshold value OVeref during EV driving, the internal combustion engine 1 is started and lubricating oil is supplied to the exhaust-side lash adjuster 23. Therefore, the generation of hitting noises at engine start-up caused by a lack of lubricating oil in the exhaust-side lash adjuster 23 can be suppressed.

[0034] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0035] Only one of the intake side oil amount OVi or the exhaust side oil amount OBe may be calculated. The calculation of the intake side oil amount OVi and the exhaust side oil amount OBe is omitted. If the intake side leakage amount Li is equal to or greater than a predetermined threshold, or if the exhaust side leakage amount Le is equal to or greater than a predetermined threshold, the process of S130 may be executed to start the engine.

[0036] The internal combustion engine 1 does not necessarily have to include the intake variable valve mechanism 13 or the exhaust variable valve mechanism 16. The vehicle is not limited to a series-parallel hybrid vehicle, but may be, for example, a parallel hybrid vehicle or a series hybrid vehicle. [Explanation of symbols]

[0037] 1...internal combustion engine, 2...combustion chamber, 3...intake passage, 3a...intake port, 4...fuel injector, 7...crankshaft, 8...exhaust passage, 8a...exhaust port, 9...intake valve, 10...exhaust valve, 11...intake camshaft, 12...exhaust camshaft, 13...intake side variable valve train, 16...exhaust side variable valve train, 19...rocker arm, 20...intake side lash adjuster, 22...rocker arm, 23...exhaust side lash adjuster, 38...oil temperature sensor, 50...planetary gear mechanism, 52...first motor generator, 52a...rotating shaft, 54...second motor generator, 54a...rotating shaft, 60...drive wheel, 70...oil pump, 100...control device

Claims

[Claim 1] A control device that is applied to a vehicle having an internal combustion engine equipped with a hydraulic lash adjuster in a valve train to which lubricating oil is supplied during engine operation, and a motor for driving the vehicle, comprising: performing a calculation process and a start process when the vehicle is traveling by the motor with the internal combustion engine stopped; the calculation process is a process of calculating an amount of lubricating oil in the lash adjuster based on a time when a crank angle of the internal combustion engine is within a predetermined range and a temperature of lubricating oil supplied to the lash adjuster, The start process is a process of starting the internal combustion engine when the calculated lubricant amount is equal to or less than a predetermined threshold value. A control device for an internal combustion engine.

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