JP5408514B2 - Variable valve timing control device for internal combustion engine - Google Patents

Description

  The present invention provides a variable internal combustion engine that includes an intermediate lock mechanism that locks a rotational phase of a camshaft with respect to a crankshaft of an internal combustion engine (engine) (hereinafter referred to as a “VCT phase”) with an intermediate lock phase located within an adjustable range. The invention relates to a valve timing control device.

  Conventionally, in a hydraulically driven variable valve timing device, as described in Patent Document 1 (Japanese Patent Laid-Open No. 9-324613) and Patent Document 2 (Japanese Patent Laid-Open No. 2001-159330), the engine is stopped. The lock phase is set approximately in the middle of the adjustable range of the VCT phase to expand the adjustable range of the valve timing (VCT phase). In this system, the intermediate lock phase that is locked when the engine is stopped is set to a phase that is suitable for starting, and the engine is started with this intermediate lock phase. Then, the variable valve timing device is filled with oil, then the lock is released and the VCT phase is controlled to the target VCT phase set according to the engine operating state.

JP-A-9-324613 JP 2001-159330 A

  By the way, in the variable valve timing device with an intermediate lock mechanism, since the engine is locked at the intermediate lock phase while the engine is stopped, both the advance chamber and the retard chamber are quickly filled with oil after the engine is started. There is a need. Therefore, in the locked state, the advance chamber and the retard chamber are communicated with each other through the communication passage, and the oil supplied to the advance chamber is supplied to the retard chamber through the communication passage, and the oil supply oil passage for the retard chamber is also provided. Is opened to the drain, and the air in each room that disturbs the oil supply is discharged to the drain to improve the oil filling performance.

  In this configuration, a part of the oil filled in the retard chamber is discharged to the drain when the oil is filled, and the oil is consumed wastefully. For this reason, there is a concern that the oil lubrication is insufficient at the time of oil filling and the engine lubricity is deteriorated.

  Accordingly, the problem to be solved by the present invention is to provide a variable valve timing control device for an internal combustion engine that can avoid deterioration in lubricity of the internal combustion engine due to oil filling into the advance chamber and retard chamber.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a hydraulically driven variable valve that adjusts the valve timing by changing the rotational phase of the camshaft (hereinafter referred to as “VCT phase”) with respect to the crankshaft of the internal combustion engine. A timing device, a lock pin for locking the VCT phase with an intermediate lock phase located within the adjustable range, an advance chamber for driving the VCT phase to the advance side, a retard chamber for driving the retard side, and the lock pin A hydraulic control valve that controls a hydraulic pressure supplied to a hydraulic chamber to be driven; and an oil pump that supplies oil for lubricating an internal combustion engine to the hydraulic control valve, and the variable valve timing device projects the lock pin. By switching the hydraulic control valve so as to lock the VCT phase with the intermediate lock phase, the advance chamber and the retard chamber can be switched to a communication state. An internal combustion engine configured to supply oil to one of the two chambers in a state where the advance chamber and the retard chamber are in communication with each other when the hydraulic control valve is in the oil filling mode. In the variable valve timing control device of the engine, when the abnormality that the hydraulic control valve cannot change from the oil filling mode occurs, the oil amount for executing the oil amount securing control for controlling the oil discharge amount of the oil pump to be a predetermined value or more The configuration is provided with securing control.

  In the present invention, even when the hydraulic control valve is operating normally, the oil amount securing control may be executed when the hydraulic control valve is in the oil filling mode, but the hydraulic control valve operates normally. If this is the case, the hydraulic control valve is maintained in the oil filling mode for a relatively short time, and the state where the lubricity of the internal combustion engine has deteriorated does not last long. When an abnormality in which the valve cannot be changed from the oil filling mode occurs, a state in which the lubricity of the internal combustion engine has deteriorated continues for a long time, which may lead to the worst situation such as seizure.

  Therefore, as in the present invention, when an abnormality that the hydraulic control valve cannot change from the oil filling mode occurs, an oil amount securing control is performed to control the oil discharge amount of the oil pump to be a predetermined value or more. For example, even if an abnormality that the hydraulic control valve cannot change from the oil filling mode occurs, the oil amount to be used for lubricating the internal combustion engine can be secured by the oil amount securing control, and the lubricity of the internal combustion engine can be secured.

  Here, the “abnormality that cannot be changed from the oil filling mode” means an abnormality in which the hydraulic control valve is stuck in the oil filling mode (Claim 2), or an abnormality in which the drive signal of the hydraulic control valve is fixed in the oil filling mode ( Claim 3). Further, when the hydraulic control valve is configured to be in the oil filling mode when the energization is turned off as in claim 4, an abnormality in which the hydraulic control valve cannot be energized due to disconnection or the like is also “oil filling”. "Unable to change from mode".

  Further, as in claim 5, when the state where the VCT phase is locked at the intermediate lock phase continues for a predetermined time, the control for temporarily releasing the lock is executed. If the lock cannot be released, the hydraulic control valve is filled with oil. It may be determined that an abnormality that cannot be changed from the mode has occurred. Thereby, it is possible to monitor whether or not an abnormality that the hydraulic control valve cannot change from the oil filling mode has occurred during the lock period.

  Further, the rotational speed of the internal combustion engine that drives the oil pump may be increased during execution of the oil amount securing control. By increasing the rotational speed of the internal combustion engine, the oil discharge amount of the oil pump can be increased.

  Further, as in claim 7, when the oil pump is a variable displacement pump, the capacity of the oil pump may be increased during execution of the oil amount securing control. By increasing the capacity of the oil pump, the oil discharge amount of the oil pump can be increased.

  Further, as in claim 8, the region for executing the oil amount securing control may be limited based on at least one of the rotational speed of the internal combustion engine and the oil temperature. When the rotational speed of the internal combustion engine is high, the oil discharge amount of the oil pump increases. Therefore, the amount of oil used for lubricating the internal combustion engine can be secured without performing the oil amount securing control. Further, when the oil temperature is low, the oil viscosity becomes high and the oil leakage is reduced. Therefore, the amount of oil used for lubricating the internal combustion engine can be secured without executing the oil amount securing control. Therefore, if the region for executing the oil amount securing control is limited based on the rotational speed of the internal combustion engine and the oil temperature, the region in which the amount of oil used for lubricating the internal combustion engine can be secured without performing the oil amount securing control. Thus, it is not necessary to execute the oil amount securing control.

FIG. 1 is a schematic configuration diagram of the entire control system showing Embodiment 1 of the present invention. FIG. 2 is a longitudinal side view for explaining the configuration of the variable valve timing device and the hydraulic control circuit. FIG. 3 is a longitudinal front view of the variable valve timing device. FIG. 4 is a diagram for explaining the relationship between the state of the lock pin and the communication / blocking between the advance chamber and the retard chamber, and (a) is a block between the advance chamber and the retard chamber in the unlocked state. The figure explaining a state, (b) is a figure explaining the communication state between the advance chamber and the retard chamber in the normal locked state. FIG. 5 is a diagram for explaining the control characteristics of the variable valve timing device. FIG. 6 is a flowchart showing a flow of processing of the oil amount securing control program according to the first embodiment. FIG. 7 is a flowchart illustrating a flow of processing of the abnormality diagnosis program according to the first embodiment. FIG. 8 is a flowchart showing the flow of processing of the abnormality diagnosis program according to the second embodiment. FIG. 9 is a flowchart showing a flow of processing of the oil amount securing control program according to the third embodiment.

  Hereinafter, three embodiments 1 to 3 in which the embodiment for carrying out the present invention is applied to a variable valve timing apparatus for an intake valve will be described.

  A first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, in an engine 11 that is an internal combustion engine, power from a crankshaft 12 is transmitted to an intake side camshaft 16 and an exhaust side camshaft 17 via sprockets 14 and 15 by a timing chain 13. It is like that. However, the intake side camshaft 16 is provided with a variable valve timing device 18 (VCT) that adjusts the advance amount (VCT phase) of the intake side camshaft 16 with respect to the crankshaft 12.

  A cam angle sensor 19 that outputs a cam angle signal pulse at a specific cam angle for cylinder discrimination is installed on the outer peripheral side of the intake side cam shaft 16, while a predetermined angle is provided on the outer peripheral side of the crank shaft 12. A crank angle sensor 20 that outputs a crank angle signal pulse for each crank angle is provided. The output signals from the cam angle sensor 19 and the crank angle sensor 20 are input to an engine control circuit 21, which calculates the actual valve timing (actual VCT phase) of the intake valve and the crank angle sensor 20. The engine speed is calculated based on the frequency (pulse interval) of the output pulses. Further, output signals from various sensors (intake pressure sensor 22, water temperature sensor 23, throttle sensor 24, etc.) for detecting the engine operating state are input to the engine control circuit 21.

  The engine control circuit 21 performs fuel injection control and ignition control according to the engine operating state detected by the various sensors, and also performs variable valve timing control (phase feedback control), and actual valve timing (actual VCT of the intake valve). The hydraulic pressure for driving the variable valve timing device 18 is feedback-controlled so that the phase) matches the target valve timing (target VCT phase).

Next, the configuration of the variable valve timing device 18 (VCT) will be described based on FIG. 2 and FIG.
A housing 31 of the variable valve timing device 18 is fastened and fixed with bolts 32 to a sprocket 14 that is rotatably supported on the outer periphery of the intake camshaft 16. Thereby, the rotation of the crankshaft 12 is transmitted to the sprocket 14 and the housing 31 via the timing chain 13, and the sprocket 14 and the housing 31 rotate in synchronization with the crankshaft 12.

On the other hand, a rotor 35 is fastened and fixed to one end of the intake side camshaft 16 with a bolt 37. The rotor 35 is housed in the housing 31 so as to be relatively rotatable.
As shown in FIG. 3, a plurality of vane storage chambers 40 are formed inside the housing 31, and each vane storage chamber 40 is retarded from the advance chamber 42 by the vane 41 formed on the outer peripheral portion of the rotor 35. It is partitioned into a chamber 43. At both sides of at least one vane 41, a stopper portion 56 is formed that restricts the relative rotation range of the rotor 35 (vane 41) with respect to the housing 31, and the actual VCT phase (cam shaft phase) is adjusted by the stopper portion 56. The most retarded angle phase and the most advanced angle phase of the possible range are regulated.

  The variable valve timing device 18 is provided with an intermediate lock mechanism 50 that locks the VCT phase with an intermediate lock phase located approximately in the middle of the adjustable range. The configuration of the intermediate lock mechanism 50 will be described. Any one or a plurality of vanes 41 is provided with a lock pin accommodation hole 57, and the lock pin accommodation hole 57 has a relative relationship between the housing 31 and the rotor 35 (vane 41). A lock pin 58 for locking the rotation is accommodated so as to protrude, and the lock pin 58 protrudes toward the sprocket 14 and fits into the lock hole 59 of the sprocket 14, so that the VCT phase is substantially in the middle of the adjustable range. Locked with an intermediate lock phase located at. This intermediate lock phase is set to a predetermined phase suitable for starting the engine 11. The lock hole 59 may be provided in the housing 31.

  The lock pin 58 is urged in the lock direction (projection direction) by the spring 62. Further, between the outer peripheral portion of the lock pin 58 and the lock pin accommodation hole 57, an unlocking hydraulic chamber for controlling the hydraulic pressure for driving the lock pin 58 in the unlocking direction is formed. Further, the housing 31 is provided with a spring 55 (see FIG. 2) such as a torsion coil spring as urging means for assisting the hydraulic pressure for relatively rotating the rotor 35 in the advance direction during the advance angle control. . In the variable valve timing device 18 for the intake valve, the torque of the intake side camshaft 16 acts in a direction that retards the VCT phase. Therefore, the spring 55 has a direction opposite to the torque direction of the intake side camshaft 16. Will be urged in the advance direction.

  In the first embodiment, the range in which the spring 55 acts is set to the range from the most retarded phase to immediately before the intermediate lock phase, and the lock is assumed assuming fail-safe at restart after abnormal stop such as engine stall. When starting with the actual VCT phase retarded from the intermediate lock phase with the pin 58 removed from the lock hole 59, the actual VCT phase is adjusted by the spring force of the spring 55 during cranking by the starter (not shown). The lock pin 58 is fitted into the lock hole 59 and can be locked by assisting the advance operation of advancing from the retard side to the intermediate lock phase.

  On the other hand, when starting with the actual VCT phase on the advance side from the intermediate lock phase, the torque on the intake side camshaft 16 acts in the retarding direction during cranking, so the actual VCT phase is caused by the torque on the intake side camshaft 16. Can be retarded from the advance side to the intermediate lock phase to lock the lock pin 58 into the lock hole 59.

  Further, in the first embodiment, as shown in FIG. 4, the rotor 35 is formed with a communication passage 63 for communicating the advance chamber 42 and the retard chamber 43, as shown in FIG. In addition, in the unlocked state in which the lock pin 58 is extracted from the lock hole 59, the communication path 63 between the advance chamber 42 and the retard chamber 43 is maintained in a state where it is blocked by the lock pin 58. . As shown in FIG. 4B, when the lock pin 58 protrudes and fits into the lock hole 59, the communication path 63 between the advance chamber 42 and the retard chamber 43 is opened. Thus, the oil can be kept in and out of the advance chamber 42 and the retard chamber 43.

  In the first embodiment, the hydraulic control valve 25 that controls the VCT phase of the variable valve timing device 18 and the hydraulic pressure that drives the lock pin 58 is a hydraulic control valve function for phase control that controls the hydraulic pressure that drives the VCT phase. And the oil pressure control valve functioning as a lock control for controlling the oil pressure for driving the lock pin 58, and the oil in the oil pan 27 is driven by the oil pump 28 driven by the power of the engine 11. (Hydraulic oil) is pumped up and supplied to the hydraulic control valve 25. The hydraulic control valve 25 is constituted by, for example, an 8-port / four-position type spool valve, and, as shown in FIG. 5, the lock modes L1, L2, the advance mode are controlled according to the control duty (control amount) of the hydraulic control valve 25. The control area is divided into four control areas: angular mode A, holding mode H, and retarding mode R.

  In the control region of the lock modes L1 and L2, the oil supply oil passage in the lock release hydraulic chamber in the lock pin accommodation hole 57 is shut off, and the oil pressure in the lock release hydraulic chamber in the lock pin accommodation hole 57 is released, and the spring 62 causes the lock pin 58 to protrude in the locking direction.

  Further, in the control region of the lock modes L1 and L2, the oil supply oil passage of the advance chamber 42 is opened while oil is supplied to the advance chamber 42 while the lock pin 58 protrudes, and the retard chamber 43 is supplied through the communication passage 63. In addition, the control region is divided into an oil filling mode L1 in which oil is filled and a control region in a lock holding mode L2 in which the oil supply oil passage in the advance chamber 42 is blocked while the lock pin 58 is projected.

  In the control region of the lock modes L1 and L2, the retard chamber 43 is opened to the drain. As a result, in the control region of the oil filling mode L1, the air in the chambers 42 and 43 that interferes with the oil supply is discharged to the drain to improve the oil filling property.

  In the control region of the advance angle mode A, the oil supply oil passage of the retard chamber 43 is shut off, the retard chamber 43 is opened to the drain, and the hydraulic pressure of the retard chamber 43 is released. According to the control duty, the oil supply oil passage of the advance chamber 42 is opened, oil is supplied to the advance chamber 42, and the hydraulic pressure of the advance chamber 42 is changed to advance the actual VCT phase.

In the control region of the holding mode H, the oil supply oil passages of both the advance chamber 42 and the retard chamber 43 are shut off, and the oil pressures of both the chambers 42 and 43 are held so that the actual VCT phase does not move. .
In the control region of the retard angle mode R, the oil supply oil passage of the advance chamber 42 is shut off, the advance chamber 42 is opened to the drain, and the hydraulic pressure of the advance chamber 42 is released. According to the control duty, the oil supply oil passage to the retard chamber 43 is opened, oil is supplied to the retard chamber 43, and the hydraulic pressure of the retard chamber 43 is changed to retard the actual VCT phase.

  In control regions other than the lock modes L1 and L2 (advance mode A, hold mode H, retard mode R), the oil supply oil passage in the lock release hydraulic chamber in the lock pin accommodation hole 57 is opened to release the lock. The hydraulic chamber is filled with oil to increase the hydraulic pressure in the unlocking hydraulic chamber, and the lock pin 58 is extracted from the lock hole 59 by the hydraulic pressure to unlock the lock pin 58.

  As described above, in the control region of the oil filling mode L1, the oil supply oil passage of the advance chamber 42 is opened while the communication passage 63 between the advance chamber 42 and the retard chamber 43 is opened, In addition, since the retard chamber 43 is opened to the drain, a part of the oil filled in the retard chamber 43 is discharged to the drain, and the oil is wasted and used for lubricating the engine 11. There is a concern of running out of oil. For this reason, when an abnormality in which the hydraulic control valve 25 cannot change from the oil filling mode L1 occurs, a state where the oil to be used for the lubrication of the engine 11 is insufficient lasts for a long time. May occur.

  Therefore, in the first embodiment, the engine control circuit 21 executes an oil amount securing control program shown in FIG. 6 to be described later, so that when an abnormality that the hydraulic control valve 25 cannot change from the oil filling mode occurs, Oil amount securing control is executed to control the oil discharge amount 28 so as to be equal to or greater than a predetermined value capable of securing the oil amount to be used for lubricating the engine 11.

  Here, the “abnormality that cannot be changed from the oil filling mode” is an abnormality in which the hydraulic control valve 25 is fixed in the oil filling mode, or an abnormality in which the drive signal of the hydraulic control valve 25 is fixed in the oil filling mode. Further, as in the first embodiment, when the hydraulic control valve 25 is configured to be in the oil filling mode when the energization is turned off, an abnormality in which the hydraulic control valve 25 is unable to be energized due to disconnection or the like, It becomes “abnormality that cannot be changed from oil filling mode”.

Further, as a method of increasing the oil discharge amount of the oil pump 28 by the oil amount securing control, the engine rotational speed for driving the oil pump 28 may be increased.
Alternatively, when the oil pump 28 is a variable displacement pump, the oil discharge amount may be increased by increasing the capacity of the oil pump 28 during execution of the oil amount securing control.

  By the way, when the engine rotation speed is high, the oil discharge amount of the oil pump 28 increases, so that it is possible to secure the amount of oil used for lubricating the engine 11 without performing the oil amount securing control. Further, when the oil temperature is low, the viscosity of the oil is increased and the oil leakage is reduced. Therefore, the amount of oil used for the lubrication of the engine 11 can be ensured without executing the oil amount securing control.

  In consideration of these circumstances, in the first embodiment, when an abnormality that the hydraulic control valve 25 cannot change from the oil filling mode occurs, the engine speed is equal to or lower than the predetermined speed and / or the oil temperature is equal to the predetermined temperature. The oil amount securing control is executed only when the above conditions are satisfied.

  The oil amount securing control according to the first embodiment described above is executed by the engine control circuit 21 according to the programs shown in FIGS. Hereinafter, the processing contents of each program of FIGS. 6 and 7 will be described.

[Oil quantity securing control program]
The oil amount securing control program in FIG. 6 is repeatedly executed by the engine control circuit 21 at a predetermined period during engine operation, and serves as oil amount securing control means in the claims.

  When this program is started, it is first determined in step 101 whether or not an abnormality that the hydraulic control valve 25 cannot change from the oil filling mode has occurred based on the processing result of the abnormality diagnosis program of FIG. If it is determined that the abnormality has not occurred, the program is terminated without doing anything.

  On the other hand, if it is determined in step 101 that an abnormality that the hydraulic control valve 25 cannot change from the oil filling mode has occurred, the process proceeds to step 102 where the engine speed is equal to or lower than the predetermined speed and the oil temperature is predetermined. It is determined whether or not a temperature or higher condition is satisfied. Here, it may be determined whether or not a condition that the engine rotational speed is equal to or lower than the predetermined rotational speed or the oil temperature is equal to or higher than the predetermined temperature is satisfied. Alternatively, only the condition of either the engine speed or the oil temperature may be determined. The oil temperature may be detected by a temperature sensor, the oil temperature is estimated from the cooling water temperature detected by the cooling water temperature sensor, the oil temperature is estimated from the travel history, or the oil temperature is determined from the oil temperature of the automatic transmission. The temperature may be estimated, or the oil temperature may be estimated by combining a plurality of estimation methods from these.

  If the condition of step 102 is not satisfied, it is determined that the oil amount to be used for lubricating the engine 11 can be secured without executing the oil amount securing control, and the program is terminated without doing anything.

  On the other hand, if the condition of step 102 is satisfied, it is determined that the amount of oil to be used for lubricating the engine 11 cannot be secured, and the process proceeds to step 103 where the engine rotation speed for driving the oil pump 28 is set to the engine 11. The oil is increased to a rotational speed that can secure the amount of oil used for lubrication. Alternatively, when the oil pump 28 is a variable displacement pump, the capacity of the oil pump 28 may be increased to a capacity that can secure the amount of oil for lubricating the engine 11.

  If the abnormality that the hydraulic control valve 25 cannot change from the oil filling mode occurs without proceeding to step 102, the process proceeds to step 103 to increase the engine speed regardless of the engine speed and oil temperature. (Or the capacity of the oil pump 28 may be increased).

[Abnormality diagnosis program]
The abnormality diagnosis program of FIG. 7 is repeatedly executed by the engine control circuit 21 at a predetermined cycle during engine operation. When this program is started, it is first determined in step 201 whether or not the hydraulic control valve 25 cannot be energized due to disconnection or the like. Then, it is determined that the hydraulic control valve 25 is “abnormality that cannot be changed from the oil filling mode”.

  On the other hand, if it is determined in step 201 that the hydraulic control valve 25 is not energized (can be energized), the process proceeds to step 202, and whether or not the drive signal of the hydraulic control valve 25 is fixed in the oil filling mode. Determine whether. This determination may be made, for example, by determining whether or not the drive signal of the hydraulic control valve 25 can be changed from the oil filling mode. If it is determined in step 202 that the drive signal of the hydraulic control valve 25 is fixed in the oil filling mode, the process proceeds to step 205, and the hydraulic control valve 25 is “abnormality that cannot be changed from the oil filling mode”. Is determined.

  On the other hand, if it is determined in step 202 that the drive signal of the hydraulic control valve 25 is not fixed in the oil filling mode, the process proceeds to step 203 to determine whether or not the VCT phase is fixed at the intermediate lock phase. judge. This determination may be made, for example, by determining whether or not the lock release control can be temporarily executed to release the lock (whether or not the VCT phase can be changed from the intermediate lock phase). If it is determined in step 203 that the VCT phase is fixed at the intermediate lock phase, the process proceeds to step 205, where it is determined that the hydraulic control valve 25 is “abnormality that cannot be changed from the oil filling mode”. This is because the VCT phase cannot be changed from the intermediate lock phase if the “abnormality that cannot be changed from the oil filling mode” occurs in the hydraulic control valve 25.

If all the determination results in Steps 201 to 203 are “No”, the process proceeds to Step 204 to determine that the hydraulic control valve 25 is normal.
Note that any one or two of the determinations in steps 201 to 203 may be omitted.

  According to the first embodiment described above, when the abnormality that the hydraulic control valve 25 cannot change from the oil filling mode occurs, the oil discharge amount of the oil pump 28 is controlled so as to become a predetermined value or more. Even if an abnormality that the hydraulic control valve 25 cannot change from the oil filling mode occurs, the amount of oil to be used for the lubrication of the engine 11 can be secured, the lubricity of the engine 11 can be secured, and the engine 11 can be seized. It can be prevented from occurring.

  In the second embodiment of the present invention, the engine control circuit 21 executes the abnormality diagnosis program shown in FIG. 8 at a predetermined cycle, so that the VCT phase is temporarily locked every time the locked state of the intermediate lock phase continues for a predetermined time. If the control for releasing is executed and the lock cannot be released, it is determined that an abnormality that the hydraulic control valve 25 cannot change from the oil filling mode has occurred.

  In the abnormality diagnosis program shown in FIG. 8, first, at step 301, it is determined whether or not the VCT phase is the lock mode locked with the intermediate lock phase. If there is, the process proceeds to step 302, where it is determined whether or not the state of the lock mode has continued for a predetermined time.

  Thereafter, when the state of the lock mode continues for a predetermined time, the process proceeds from step 302 to step 303, the lock release control is temporarily executed, and whether or not the lock is actually released in the next step 303 (VCT phase). Is determined from the intermediate lock phase). As a result, if it is determined that the lock cannot be released, the process proceeds to step 307, where it is determined that the hydraulic control valve 25 is “abnormality that cannot be changed from the oil filling mode”. This is because the lock cannot be released if the “abnormality that cannot be changed from the oil filling mode” occurs in the hydraulic control valve 25.

On the other hand, if it is determined in step 304 that the lock can be released, the process proceeds to step 305, where it is determined that the hydraulic control valve 25 is normal, and in the next step 306, lock control is executed, and VCT is performed. Return the phase locked to the intermediate lock phase.
Other matters are the same as those in the first embodiment.

  In the first embodiment, when an abnormality that the hydraulic control valve 25 cannot change from the oil filling mode occurs, the oil amount securing control is performed to control the oil discharge amount of the oil pump 28 to be a predetermined value or more. However, in the third embodiment of the present invention, the oil discharge amount of the oil pump 28 is changed to the engine 11 when the hydraulic control valve 25 is in the oil filling mode by executing the oil amount securing control program of FIG. Oil amount securing control is performed to control the oil amount to be equal to or greater than a predetermined value that can ensure the amount of oil to be used for lubrication.

  Since the variable valve timing device 18 with the intermediate lock mechanism 50 is locked at the intermediate lock phase while the engine is stopped, oil is quickly supplied to both the advance chamber 42 and the retard chamber 43 after the engine is started. Need to be filled. Therefore, when the engine is started, the hydraulic control valve 25 is in the oil filling mode, and a part of the oil filled in the retarding chamber 43 is discharged to the drain, so that the oil is wasted, and the engine 11 There is a concern that there will be insufficient oil for lubrication.

  Therefore, in the third embodiment, it is determined in step 101a of the oil amount securing control program in FIG. 9 whether or not the hydraulic control valve 25 is in the oil filling mode, and the hydraulic control valve 25 is in the oil filling mode. If not, the program is terminated without doing anything.

  On the other hand, if it is determined in step 101a that the hydraulic control valve 25 is in the oil filling mode, the process proceeds to step 102 where the engine speed is equal to or lower than the predetermined speed and / or the oil temperature is equal to the predetermined temperature. It is determined whether or not the above condition is satisfied, and if this condition is not satisfied, it is determined that the oil amount to be used for lubricating the engine 11 can be secured without executing the oil amount securing control, and nothing is done as it is. Quit this program without

  On the other hand, if the condition of step 102 is satisfied, it is determined that the amount of oil to be used for the lubrication of the engine 11 cannot be secured, and the process proceeds to step 103 where the engine rotation speed for driving the oil pump 28 is set to the lubrication of the engine 11. Increase the rotation speed to ensure sufficient oil volume. Alternatively, when the oil pump 28 is a variable displacement pump, the capacity of the oil pump 28 may be increased to a capacity that can secure the amount of oil for lubricating the engine 11.

  Note that the processing of step 102 is omitted, and when the hydraulic control valve 25 is in the oil filling mode, the process proceeds to step 103 regardless of the engine speed or the oil temperature, and the engine speed is increased (or the oil pump 28 The capacity may be increased).

  According to the third embodiment described above, when the oil pressure control valve 25 is in the oil filling mode, the oil amount securing control for controlling the oil discharge amount of the oil pump 28 to be equal to or greater than a predetermined value is executed. The oil discharge amount of the oil pump 28 can be controlled so as to secure the amount of oil to be used for lubrication of the engine 11 when the corner chamber 42 and the retard chamber 43 are filled with oil, and the advance chamber 42 and the retard chamber 43 are controlled. It is possible to avoid deterioration in lubricity of the engine 11 due to oil filling.

  In addition, when the hydraulic control valve 25 is in the oil filling mode, the oil amount securing control may be executed intermittently (the execution / stop of the oil amount securing control is alternately switched at predetermined intervals). Is also good). Even in this case, when the hydraulic control valve 25 is in the oil filling mode, the amount of oil used for the lubrication of the engine 11 can be increased intermittently, so that the lubricity of the engine 11 can be ensured.

  The first to third embodiments are embodiments in which the present invention is applied to an intake valve variable valve timing device, but may be applied to an exhaust valve variable valve timing device. When the present invention is applied to a variable valve timing device for an exhaust valve, the VCT phase control direction of the exhaust valve (the relationship between “advance angle” and “retard angle”) is opposite to the control direction of the VCT phase of the intake valve. Just do it.

  In addition, it goes without saying that the present invention can be implemented with various modifications within a range not departing from the gist, such as appropriately changing the configuration of the variable valve timing device 18 and the configuration of the hydraulic control valve 25.

  DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... Crankshaft, 13 ... Timing chain, 14, 15 ... Sprocket, 16 ... Intake camshaft, 17 ... Exhaust camshaft, 18 ... Variable valve timing device (VCT), 19 ... Cam angle Sensor: 20 ... Crank angle sensor, 21 ... Engine control circuit (oil amount securing control means), 25 ... Hydraulic control valve, 28 ... Oil pump, 31 ... Housing, 35 ... Rotor, 40 ... Vane storage chamber, 41 ... Vane, 42 ... Advance chamber, 43 ... Delay chamber, 50 ... Intermediate lock mechanism, 55 ... Spring, 58 ... Lock pin, 59 ... Lock hole, 62 ... Spring, 63 ... Communication path

Claims (8)

A hydraulically driven variable valve timing device that adjusts the valve timing by changing the rotational phase of the camshaft relative to the crankshaft of the internal combustion engine (hereinafter referred to as “VCT phase”), and an intermediate lock that positions the VCT phase within its adjustable range A lock pin that locks in phase, an advance chamber that drives the VCT phase to the advance side, a retard chamber that drives to the retard side, and a hydraulic control valve that controls the hydraulic pressure supplied to the hydraulic chamber that drives the lock pin; An oil pump for supplying oil for lubrication of the internal combustion engine to the hydraulic control valve, and the variable valve timing device projects the lock pin so that the VCT phase is locked at the intermediate lock phase. It is configured to switch to a state where the advance chamber and the retard chamber are communicated by controlling a valve, and the hydraulic control valve is in an oil filling mode. In the variable valve timing control system for an internal combustion engine to fill the oil by supplying the oil to the one chamber in a state of communicating with the two chambers and the retarded angle chamber and the advanced angle chamber to come,
Oil amount securing control means for performing oil amount securing control for controlling the oil discharge amount of the oil pump to become a predetermined value or more when an abnormality that the hydraulic control valve cannot change from the oil filling mode occurs. A variable valve timing control device for an internal combustion engine characterized by comprising:   2. The variable valve timing control device for an internal combustion engine according to claim 1, wherein the abnormality that cannot be changed from the oil filling mode is an abnormality in which the hydraulic control valve is stuck in the oil filling mode.   2. The variable valve timing control device for an internal combustion engine according to claim 1, wherein the abnormality that cannot be changed from the oil filling mode is an abnormality in which a drive signal of the hydraulic control valve is fixed to the oil filling mode.   The hydraulic control valve is configured to be in the oil filling mode when energization is turned off, and the abnormality that cannot be changed from the oil filling mode is an abnormality in which the hydraulic control valve cannot be energized. The variable valve timing control device for an internal combustion engine according to claim 1.   The oil amount securing control means performs a control for temporarily releasing the lock every time the state where the VCT phase is locked by the intermediate lock phase continues for a predetermined time, and if the lock cannot be released, the hydraulic control valve 5. The variable valve timing control apparatus for an internal combustion engine according to claim 1, wherein it is determined that an abnormality that cannot be changed from the oil filling mode has occurred.   6. The internal combustion engine according to claim 1, wherein the oil amount securing control means increases the rotational speed of the internal combustion engine that drives the oil pump during the execution of the oil amount securing control. Variable valve timing control device. The oil pump is composed of a variable displacement pump,
6. The variable valve timing control device for an internal combustion engine according to claim 1, wherein the oil amount securing control means increases the capacity of the oil pump during execution of the oil amount securing control.   The internal combustion engine according to any one of claims 1 to 7, wherein the oil amount securing control means limits a region in which the oil amount securing control is executed based on at least one of an internal combustion engine rotation speed and an oil temperature. Variable valve timing control device for engine.

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