JP4140437B2 - Variable valve timing device for engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an engine variable valve timing device capable of changing the opening / closing timing of an engine valve.
[0002]
[Prior art]
  2. Description of the Related Art Conventionally, an engine variable valve timing device that can change the opening / closing timing of an engine valve is known (see, for example, Patent Document 1). This variable valve timing device includes a variable valve timing mechanism in which an advance hydraulic chamber and a retard hydraulic chamber are formed, a hydraulic control valve that controls hydraulic pressure supplied to the variable valve timing mechanism, a variable valve timing mechanism, and the like. And an oil passage through which supplied hydraulic oil flows. Then, by controlling the hydraulic pressure supplied to the advance hydraulic chamber and the retard hydraulic chamber of the variable valve timing mechanism by the hydraulic control valve, the relative phase of the camshaft with respect to the crankshaft is changed to control the valve opening / closing timing. change.
[0003]
  In addition, since the variable valve timing mechanism generally has a large capacity and is provided at the end of the oil passage, in the variable valve timing device, the hydraulic pressure does not readily act on other devices other than the variable valve timing mechanism. . Therefore, for example, an attempt has been made to suppress the possibility of adverse effects caused by the variable valve timing mechanism by improving the discharge characteristics of the oil pump.
[0004]
[Patent Document 1]
          JP-A-7-109907
[0005]
[Problems to be solved by the invention]
  By the way, the present inventors have noticed that an abnormal sound such as a jagged noise is generated after an engine complete explosion at the time of engine start in an engine that has been used for a long time. Here, “complete explosion” means a state in which all of the cylinders installed in the engine have exploded.
[0006]
  Therefore, the present inventors have conducted various studies to find out the cause of the occurrence of this abnormal sound, and as a result, the following has been found. That is, as a cause of the occurrence of this abnormal noise, there is a chain spanned between the crankshaft and the camshaft, and a hydraulic chain tensioner provided on the upstream side of the variable valve timing mechanism and applying tension to the chain. It turns out that there is a relationship. Specifically, the chain that has been extended over many years and the chain tensioner arm with insufficient hydraulic pressure during the engine start-up process flutters in a low cycle when the engine speed is low, and When the engine speed increased, the flutter was reproduced with a high cycle, and abnormal noise was generated.
[0007]
  In addition, when various tests were performed in order to determine the conditions under which this phenomenon is likely to occur, it tends to occur when the chain elongation exceeds a predetermined elongation amount, and the smaller the remaining amount of hydraulic oil in the oil passage, It was found that the possibility of the occurrence was high. It has also been found that this phenomenon occurs in certain engines.
[0008]
  The occurrence of this abnormal noise not only impairs the merchantability of the engine but also may impair the reliability of the chain tensioner, and is a problem to be solved.
[0009]
  Here, in the engine variable valve timing device according to Patent Document 1, the hydraulic control valve is closed for a predetermined period each time the engine is started. Thereby, every time the engine is started, the supply of oil to the variable valve timing mechanism for a predetermined period is stopped, and the oil is supplied more quickly to the lubrication required parts such as the connecting rod and the crankshaft. Therefore, it is possible to prevent the occurrence of abnormal noise at the above-mentioned part due to insufficient lubrication at the time of engine start. However, in this variable valve timing device of the engine, there is no intention about the elongation of the chain which is the cause of the problem of the present invention, and regardless of whether the possibility of abnormal noise is high or low, Since the valve is closed, the reliability of the variable valve timing mechanism may be impaired.
[0010]
  The present invention has been made in view of this point, and an object of the present invention is to provide a hydraulic variable valve timing mechanism capable of changing the valve timing, and a hydraulic pressure for controlling the hydraulic pressure supplied to the variable valve timing mechanism. In a variable valve timing device for an engine comprising a control valve, a hydraulic chain tensioner, and an oil passage in which the chain tensioner, the hydraulic control valve, and the variable valve timing mechanism are disposed, It is intended to appropriately prevent the occurrence of abnormal noise and to ensure the reliability of the chain tensioner without impairing the reliability of the variable valve timing mechanism.
[0011]
[Means for Solving the Problems]
  1st invention is provided between the camshaft and the sprocket located in the edge part of this camshaft, The hydraulic variable valve timing mechanism which can change valve timing, and supply to this variable valve timing mechanism A hydraulic control valve for controlling the hydraulic pressure, a hydraulic chain tensioner that applies tension to the chain spanned between the sprocket and the crankshaft, the chain tensioner, the hydraulic control valve, and the variable valve in this order from the upstream side. A variable valve timing device for an engine having a timing mechanism and an oil passage through which oil discharged from an oil pump flows, and an abnormality determining means for determining whether or not the chain is in an abnormal state; Storage means for storing information on the abnormal condition when the abnormality determination means determines that the chain is in an abnormal condition; When the engine is started after storage of the abnormal state information according to the storage means, it is characterized in that a control means for a predetermined period of time the hydraulic control valve in a closed state.
[0012]
  ThisAs a result, when the engine is started after storing the information on the abnormal state of the chain, the hydraulic control valve is closed for a predetermined period, so that the supply of oil to the variable valve timing mechanism having a relatively large capacity is stopped. Therefore, when the engine is started, oil is supplied to the chain tensioner more quickly. Therefore, the hydraulic pressure in the chain tensioner rises quickly, and the chain flapping can be prevented. Therefore, it is possible to prevent the occurrence of abnormal noise when starting the engine, and to ensure the reliability of the chain tensioner.
[0013]
  Further, when the abnormality determining means determines that the chain is not in an abnormal state, the hydraulic control valve is not closed when the engine is started. That is, oil is supplied to the variable valve timing mechanism when the possibility of abnormal noise occurring at the time of engine start is low. Therefore, the supply of oil to the variable valve timing mechanism is not stopped every time the engine is started, so that the reliability of the variable valve timing mechanism is not impaired.
[0014]
  As described above, the reliability of the chain tensioner can be ensured without impairing the reliability of the variable valve timing mechanism.
[0015]
  Second inventionIs the above1st inventionAnd an elapsed time measuring means for measuring an elapsed time since the engine stop, wherein the control means is after the storage of the abnormal state information by the storage means and from the engine stop measured by the elapsed time measuring means. The hydraulic control valve is configured to be closed for the predetermined period when the engine is started for the first time after the engine is stopped when the elapsed time is equal to or longer than a set time. To do.
[0016]
  By the way, the longer the elapsed time from the engine stop to the first engine start after the engine stop, the smaller the remaining amount of oil in the oil passage. In addition, as the remaining amount of oil in the oil passage is smaller, abnormal noise is more likely to occur.
[0017]
  Here, according to the present invention, when the elapsed time from the engine stop measured by the elapsed time measuring means after the storage of the abnormal state information by the storage means is equal to or longer than the set time, When the first engine is started, the hydraulic control valve is closed for a predetermined period. That is, the supply of oil to the variable valve timing mechanism is stopped only when the possibility of abnormal noise is higher and the remaining amount of oil in the oil passage is small. Therefore, the reliability of the variable valve timing mechanism can be ensured more reliably.
[0018]
  Third inventionIs the above1st or 2nd inventionIn the above, the predetermined period is between a starter start time and a time when a predetermined time elapses after the engine speed after the starter start reaches the engine complete explosion speed for the first time. is there.
[0019]
  Here, the “engine complete explosion speed” refers to the engine speed when all of the cylinders disposed in the engine have exploded.
[0020]
  By the way, there is a time zone in which abnormal noise is likely to occur between the starter start time and the time when the engine speed after the starter start reaches the engine complete explosion speed for the first time. I know it.
[0021]
  Here, according to the present invention, a predetermined period of time has elapsed since the time when the abnormal noise is likely to occur, that is, when the starter starts and when the engine speed after the starter starts reaches the engine complete explosion speed for the first time. In between, the hydraulic control valve is closed. Therefore, the occurrence of abnormal noise can be prevented more reliably, and the reliability of the chain tensioner can be ensured more reliably.
[0022]
  4th inventionIs the aboveAny one of the first to third inventionsThe variable valve timing mechanism includes an intake camshaft variable valve timing mechanism and an exhaust camshaft variable valve timing mechanism, and the hydraulic control valve supplies the intake camshaft variable valve timing mechanism. And an exhaust camshaft hydraulic control valve for controlling the hydraulic pressure supplied to the exhaust camshaft variable valve timing mechanism, wherein the control means includes the intake camshaft. The hydraulic control valve for exhaust gas and the hydraulic control valve for exhaust camshaft are controlled.
[0023]
  By the way, a variable valve timing mechanism for intake camshaft and a variable valve timing mechanism for exhaust camshaft are provided as variable valve timing mechanisms, and a hydraulic control valve for intake camshaft and a hydraulic control valve for exhaust camshaft are provided as hydraulic control valves. It has been found that the variable valve timing device of the engine that it has is prone to abnormal noise.
[0024]
  Here, according to the present invention, since the control means controls the intake camshaft hydraulic control valve and the exhaust camshaft hydraulic control valve, when the engine is started after storing the information on the abnormal state of the chain, Both the camshaft and exhaust camshaft hydraulic control valves are closed for a predetermined period. That is, the oil supply is stopped for both the intake camshaft and exhaust camshaft variable valve timing mechanisms. Therefore, the reliability of the chain tensioner can be ensured without impairing the reliability of the variable valve timing mechanism in the variable valve timing device of the engine that is likely to generate abnormal noise.
[0025]
  In a fifth aspect of the present invention based on any one of the first to fourth aspects, the abnormality determining means is that the chain is in an abnormal state when the elongation of the chain reaches or exceeds a predetermined amount of elongation. It is characterized by being comprised so that it may determine.
[0026]
【The invention's effect】
  According to the first aspect of the invention, since the hydraulic control valve is closed for a predetermined period when the engine is started after storing the information on the abnormal state of the chain, the oil is supplied to the variable valve timing mechanism having a relatively large capacity. Is stopped. Therefore, when the engine is started, the oil is supplied to the chain tensioner more quickly, the hydraulic pressure in the chain tensioner rises quickly, and chain flapping can be prevented. Therefore, it is possible to prevent the occurrence of abnormal noise when starting the engine, and to ensure the reliability of the chain tensioner. Further, when the abnormality determining means determines that the chain is not in an abnormal state, the hydraulic control valve is not closed when the engine is started. That is, oil is supplied to the variable valve timing mechanism when the possibility of abnormal noise occurring at the time of engine start is low. Therefore, the supply of oil to the variable valve timing mechanism is not stopped every time the engine is started, so that the reliability of the variable valve timing mechanism is not impaired. As described above, the reliability of the chain tensioner can be ensured without impairing the reliability of the variable valve timing mechanism.
[0027]
  the aboveSecond inventionAccording to the present invention, after the storage of the abnormal state information by the storage means and when the elapsed time from the engine stop measured by the elapsed time measurement means is equal to or longer than the set time, the first engine start after the engine stop is If so, the hydraulic control valve is closed for a predetermined period. That is, the supply of oil to the variable valve timing mechanism is stopped only when the possibility of abnormal noise is higher and the remaining amount of oil in the oil passage is small. Therefore, the reliability of the variable valve timing mechanism can be ensured more reliably.
[0028]
  the aboveThird inventionAccording to the time zone in which abnormal noise is likely to occur, that is, between the starter start time and the time when a predetermined time has elapsed from when the engine speed after the starter start reaches the engine complete explosion speed for the first time, The hydraulic control valve is closed. Therefore, the occurrence of abnormal noise can be prevented more reliably, and the reliability of the chain tensioner can be ensured more reliably.
[0029]
  the above4th inventionSince the control means controls the intake camshaft hydraulic control valve and the exhaust camshaft hydraulic control valve, at the time of engine start after storing the information on the abnormal state of the chain, the intake camshaft and exhaust camshaft All of the camshaft hydraulic control valves are closed for a predetermined period. That is, the oil supply is stopped for both the intake camshaft and exhaust camshaft variable valve timing mechanisms. Therefore, the reliability of the chain tensioner can be ensured without impairing the reliability of the variable valve timing mechanism in the variable valve timing device of the engine that is likely to generate abnormal noise.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
  Less thanHereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0031]
  As shown in FIG. 1, a vehicle lubrication system mechanism 1 includes an oil pan 3 for storing hydraulic oil, an oil strainer 5 for filtering harmful solids and particles from the hydraulic oil, an oil pump 7, 1 oil filter 9, main bearing 11, crankshaft 13, connecting rod bearing 15, oil jet valve 17, piston 19, oil pressure switch 21, hydraulic chain tensioner 23, second oil filter 25, orifice 27, intake and exhaust side hydraulic control valves (OCV) 29 and 31, intake and exhaust camshafts 33 and 35, hydraulic intake and exhaust side variable valve timing mechanisms (VVT) 37, 39 and an oil passage 41. The intake camshaft and exhaust camshaft variable valve timing mechanisms according to the present invention correspond to the intake side and exhaust side variable valve timing mechanisms 37 and 39, respectively. The intake camshaft and exhaust camshaft hydraulic control valves are These correspond to the intake side and exhaust side hydraulic control valves 29 and 31, respectively.
[0032]
  The oil pump 7 is a device that sucks in the hydraulic oil stored in the oil pan 3 and discharges the sucked hydraulic oil using the rotation of the crankshaft 13 as power.
[0033]
  The chain tensioner 23 is a device that applies tension to the chain wound around the sprocket located at the ends of the camshafts 33 and 35 and the sprocket of the crankshaft 13 using hydraulic pressure.
[0034]
  The intake and exhaust camshafts 33 and 35 are arranged in parallel to the crankshaft 13. A plurality of cams are fixed to the cam shafts 33 and 35, respectively. A sprocket is provided in the vicinity of one end of each camshaft 33, 35.
[0035]
  The intake side and exhaust side variable valve timing mechanisms 37 and 39 are provided between the intake and exhaust camshafts 33 and 35 and sprockets located at the ends of the camshafts 33 and 35, respectively. These variable valve timing mechanisms 37 and 39 change the rotational phase angles of the intake and exhaust camshafts 33 and 35 with respect to the crankshaft 13, respectively. In other words, the variable valve timing mechanisms 37 and 39 respectively change the phase angle of the opening / closing timing of the intake valve and the exhaust valve with respect to the crankshaft 13. These variable valve timing mechanisms 37 and 39 are formed with hydraulic chambers for advance and retard. When switching the valve opening / closing timing from the advance side to the retard side, the hydraulic pressure is supplied to the advance hydraulic chamber and the hydraulic oil is discharged from the retard hydraulic chamber, while the valve opening / closing timing is advanced from the retard side. When switching to the corner side, the hydraulic oil is supplied to the retarding hydraulic chamber and simultaneously the hydraulic oil in the advance hydraulic chamber is discharged.
[0036]
  The intake side and exhaust side hydraulic control valves 29 and 31 are valves for controlling the hydraulic pressure supplied to the advance and retard angle hydraulic chambers of the intake and exhaust side variable valve timing mechanisms 37 and 39, respectively. These hydraulic control valves 29 and 31 include a hollow valve case, a spool that can move in the axial direction within the valve case, and a spring that biases the spool in one direction. Each hydraulic control valve 29, 31 is provided with one input port, first and second drain ports, and first and second output ports. The input port is connected to the hydraulic oil supply passage, and the first and second output ports are connected to the advance and retard oil passages, respectively. The hydraulic supply oil passage is a passage that supplies a control original pressure to the hydraulic control valves 29 and 31 from a hydraulic source. The advance angle and retard angle oil passages are passages for supplying the advance angle and retard angle hydraulic pressures to the advance angle and retard angle hydraulic chambers, respectively. The hydraulic supply oil passage, the advance oil passage, and the retard oil passage constitute a part of the oil passage 41.
[0037]
  The amount of movement of the spool in the axial direction is adjusted by a solenoid whose duty is controlled by a control device 61 described later. Here, when the solenoid is de-energized (for example, duty ratio = 0%) by the control device 61, the spool moves upward, and the advance oil passage and the hydraulic supply oil passage communicate with each other via the input port. To do. When the solenoid is in an excited state (for example, duty ratio = 100%), the spool moves downward, and the retarding oil passage and the hydraulic supply oil passage communicate with each other through the input port. Further, when the solenoid is in a state where excitation and non-excitation are repeated in a short cycle (for example, duty ratio = 50%), the spool is maintained at the intermediate position, and the advance and retard oil passages and the hydraulic supply oil It does not communicate with the road.
[0038]
  The oil passage 41 includes a main bearing 11, a crankshaft 13, a connecting rod bearing 15, an oil jet valve 17, a piston 19, an oil pressure switch 21, a chain tensioner 23, an intake and exhaust camshafts 33 and 35, an intake side and an exhaust side. This is a one-line passage for supplying hydraulic oil of the oil pan 3 to the variable valve timing mechanisms 37, 39 and the like. The oil passage 41 includes an oil pump 7, a first oil filter 9, a main bearing 11, an oil pressure switch 21, a chain tensioner 23, a second oil filter 25, hydraulic control valves 29 and 31, and camshafts in order from the upstream side. 33 and 35 and variable valve timing mechanisms 37 and 39 are provided.
[0039]
  As shown in FIG. 2, the variable valve timing device 43 for the engine according to the embodiment of the present invention includes the intake side and exhaust side variable valve timing mechanisms 37, 39 and the intake side and exhaust side hydraulic control valves 29, 31. The advance and retard oil passages that are part of the oil passage 41, the crankshaft sensor 45 that detects the reference position of the crankshaft, and the relative phase of the camshaft with respect to the reference position of the crankshaft. Cam angle sensor 47, learning device 49, chain abnormality detecting device 51 for detecting an abnormal state of the chain, time measuring device 53 for measuring time, engine speed sensor 55 for detecting the engine speed, and throttle valve A throttle opening sensor 57 for detecting the opening of the engine, an engine water temperature sensor 59 for detecting the temperature of the cooling water, and an engine starter A starter 60 is, and a control unit 61 for controlling the intake side and the exhaust-side oil pressure control valve 29, 31. The abnormality determining means according to the present invention corresponds to the chain abnormality detecting device 51, the control means corresponds to the control device 61, the relative phase detecting means corresponds to the crankshaft sensor 45 and the cam angle sensor 47, and the learning means is This corresponds to the learning device 49.
[0040]
  The crankshaft sensor 45 and the cam angle sensor 47 are connected to a learning device 49. The crankshaft sensor 45 and the cam angle sensor 47 are part of devices that control the variable valve timing mechanisms 37 and 39.
[0041]
  The learning device 49 is connected to a change value storage unit 51a (details of the change value storage unit 51a will be described later) and a control device 61 as addition value storage means. The learning device 49 determines that the phase shift amount Δa1 isMore than the target deviation amount ΔA1Is a device that learns and corrects the phase shift amount Δa1 when it is determined (Phase shift amount Δa1 and target shift amount ΔA1Will be described later in detail).
[0042]
  The chain abnormality detection device 51 is connected to a storage unit 61a as storage means (details of the storage unit 61a will be described later). The chain abnormality detection device 51 is a device that determines that the chain is in an abnormal state when the chain elongation exceeds a predetermined elongation amount (details regarding a method for determining an abnormal state of the chain will be described later). The chain abnormality detection device 51 includes a change value storage unit 51a. The change value storage unit 51a determines that the phase shift amount Δa1 hasMore than the target deviation amount ΔA1Is determined, the phase shift amount Δa1 is cumulatively added to the stored cumulative addition value, and the new cumulative addition value is stored. Here, the “stored cumulative addition value” is stored in the change value storage unit 51a.More than the target deviation amount ΔA1This is a value obtained by cumulatively adding the phase shift amount Δa1.
[0043]
  The time measuring device 53 is connected to a time determining unit 61 b described later, and the engine speed sensor 55, the throttle opening sensor 57, the engine water temperature sensor 59, and the starter 60 are connected to the control device 61.
[0044]
  The control device 61 is a device for duty-controlling solenoids of the intake side and exhaust side hydraulic control valves 29 and 31. The control device 61 includes a storage unit 61a and a time determination unit 61b. When the chain abnormality detection device 51 determines that the chain is in an abnormal state, the storage unit 61a stores information on the abnormal state. The time determination unit 61b determines whether or not the elapsed time from the engine stop measured by the time measuring device 53 is equal to or longer than a predetermined time (for example, 16 hours in the present embodiment). In other words, the time determination unit 61b determines whether or not the remaining amount of hydraulic oil in the oil passage 41 is less than a predetermined amount. The elapsed time measuring means according to the present invention corresponds to the time measuring device 53.
[0045]
  -Operation of variable valve timing device-
  <When flag = 1>
  Here, the operation of the variable valve timing device 43 of the engine according to the present embodiment when the flag f (details of the flag f will be described later) is 1 will be described with reference to FIGS. In the following description, only the control of the intake side hydraulic control valve 29 by the control device 61 is described, and the control of the exhaust side hydraulic control valve 31 is omitted.
[0046]
  First, the control device 61 reads various signals based on detection signals from the various sensors 55, 57, and 59. Next, the control device 61 determines whether or not the flag f is 1 (step S1). Here, the “flag” in the present embodiment is a variable indicating whether or not the chain is in an abnormal state. When the flag f = 1, the chain is in an abnormal state, and when the flag f = 0. Indicates that the chain is not in an abnormal state.
[0047]
  When it is determined that the flag f = 1, the process proceeds to step S2, and the time determination unit 61b of the control device 61 determines whether or not the elapsed time from the previous engine stop is 16 hours or more.
[0048]
  When it is determined that the elapsed time is 16 hours or longer, the process proceeds to step S3, and the control device 61 determines whether or not the starter 60 is in the ON state. That is, the control device 61 determines whether or not the starter 60 has been started.
[0049]
  When it is determined that the starter 60 is in the ON state, the control device 61 controls the solenoid so that the duty ratio of the hydraulic control valve 29 becomes 50% (step S4). That is, the control device 61 controls the hydraulic control valve 29 to close the hydraulic control valve 29. As a result, the advance and retard oil passages corresponding to the intake-side variable valve timing mechanism 37 are not in communication with the hydraulic supply oil passage. On the other hand, when the starter 60 is turned on, the oil pump 7 is also started. At this time, the hydraulic oil is not supplied to the advance and retard hydraulic chambers of the intake-side variable valve timing mechanism 37, while other devices other than the intake-side variable valve timing mechanism 37, such as the chain tensioner 23. The hydraulic oil begins to be supplied.
[0050]
  Next, the control device 61 determines whether or not the current engine speed Ne is equal to or higher than the engine complete explosion speed N1 (step S5) (see also FIG. 4). Here, “complete explosion” means a state in which all of the cylinders installed in the engine have exploded. The “engine complete explosion speed” refers to the engine speed at the time of complete engine explosion, and is generally smaller than the idle speed (for example, 600 rpm). In the present embodiment, the engine complete explosion speed N1 is, for example, 500 rpm.
[0051]
  When it is determined that the current engine speed Ne is 500 rpm or more, the timer is turned on (step S6).
[0052]
  Next, the control device 61 determines whether or not a predetermined time (in this embodiment, for example, 0.5 seconds) has elapsed since the timer was turned on (step S7).
[0053]
  When it is determined that 0.5 seconds have elapsed since the timer was turned on, the timer is turned off (step S8), and the controller 61 turns the solenoid so that the duty ratio of the hydraulic control valve 29 becomes 0%. Control (step S9). Thereby, the advance passage corresponding to the intake side valve timing mechanism 37 and the hydraulic pressure supply oil passage communicate with each other. At this time, the hydraulic oil starts to be supplied to the advance hydraulic chamber through the advance passage and the hole formed in the intake camshaft 33. Further, the hydraulic oil accumulated in advance in the retarding hydraulic chamber starts to return to the oil pan 3 by receiving the hydraulic pressure from the advance hydraulic chamber.
[0054]
  Next, the control device 61 controls the hydraulic control valve 29 based on the operating state of the engine detected by various sensors such as the engine speed sensor 55, the throttle opening sensor 57, and the engine water temperature sensor 59, for example. As a result, engine output performance and the like are optimized.
[0055]
  Next, the chain abnormality detection device 51 determines whether or not the chain is in an abnormal state. Specifically, the learning device 49 first determines that the phase shift amount Δa1 isMore than the target deviation amount ΔA1Whether or not (step S10). Here, the “phase shift amount Δa1” is an amount of deviation between the relative phase of the camshaft 33 with respect to the reference position of the crankshaft 13 and the reference relative phase of the camshaft 33 with respect to the reference position of the crankshaft 13. The “target deviation amount ΔA1” is a small target deviation amount that derives a phase deviation amount that gradually progresses over many years.To be described laterThe “target value ΔA” is a value corresponding to an elongation amount slightly smaller than the elongation amount of the chain that is highly likely to cause abnormal noise, which is obtained by an experiment performed in advance. The target value ΔA is larger than the target deviation amount ΔA1.
[0056]
  The phase shift amount Δa1 isMore than the target deviation amount ΔA1When it is determined, the change value storage unit 51a adds the phase shift amount Δa1 to the stored cumulative addition value, and stores the added cumulative addition value (step S11). At the same time, the learning device 49 learns and corrects the phase shift amount Δa1.
[0057]
  Next, the chain abnormality detection device 51 determines whether or not the cumulative addition value, that is, the actual error value Δa is equal to or greater than the target value ΔA (step S12). When it is determined that the actual error value Δa is equal to or greater than the target value ΔA, the chain abnormality detection device 51 determines that the chain is in an abnormal state and transmits an abnormality signal to the storage unit 61a of the control device 61. The storage unit 61a that has received the abnormal signal stores the information on the abnormal state (step S13), whereby the flag f is set to 1 (step S14).SoAfter this, this routine ends.
[0058]
  On the other hand, when it is determined in step S12 that the actual error value Δa is smaller than the target value ΔA, the flag f is zero.
[0059]
  <When flag = 0>
  Next, the operation of the variable valve timing device 43 of the engine when the flag f is not 1, that is, when the flag f is 0 will be described with reference to FIGS.
[0060]
  The control device 61 determines whether or not the flag f is 1 (step S1).
[0061]
  When it is determined that the flag f is not 1, the process proceeds to step S15, and the control device 61 determines whether or not the starter 60 is in the ON state.
[0062]
  When it is determined that the starter 60 is in the ON state, the control device 61 controls the solenoid so that the duty ratio of the hydraulic control valve 29 becomes 0% (step S16). As a result, the advance angle passage corresponding to the intake side variable valve timing mechanism 37 and the hydraulic pressure supply oil passage communicate with each other, and the hydraulic oil is supplied to the advance angle hydraulic chamber, and is also accumulated in advance in the retard angle hydraulic chamber. The hydraulic oil returned to the oil pan 3.
[0063]
  Next, the hydraulic control valve 29 is controlled based on the engine operating state detected by the various sensors 55, 57 and 59. The following process is substantially the same as the process in the case of the flag f = 1.
[0064]
  The control of the exhaust side hydraulic control valve 31 by the control device 61 is also performed in the same manner as the control of the intake side hydraulic control valve 29.
[0065]
  As described above, according to the present embodiment, since the hydraulic control valves 29 and 31 are closed for a predetermined period when the engine is started after the storage unit 61a stores the information on the abnormal state of the chain, the capacity is relatively large. The supply of hydraulic oil to the variable valve timing mechanisms 37 and 39 is stopped. Therefore, hydraulic oil is supplied to the chain tensioner 23 more quickly when the engine is started. Therefore, the hydraulic pressure in the chain tensioner 23 rises rapidly, and chain flapping can be prevented. Therefore, it is possible to prevent abnormal noise from occurring when the engine is started, and to ensure the reliability of the chain tensioner 23. When the chain abnormality detecting device 51 determines that the chain is not in an abnormal state, the hydraulic control valves 29 and 31 are not closed when the engine is started. That is, when the possibility of occurrence of abnormal noise during engine startup is low, hydraulic oil is supplied to the variable valve timing mechanisms 37 and 39. Therefore, the supply of hydraulic oil to the variable valve timing mechanisms 37 and 39 is not stopped every time the engine is started, and the reliability of the variable valve timing mechanisms 37 and 39 is not impaired. As described above, the reliability of the chain tensioner 23 can be ensured without impairing the reliability of the variable valve timing mechanisms 37 and 39.
[0066]
  Also, the time period during which abnormal noise is likely to occur, that is, when the starter 60 starts and when the engine speed after the starter 60 starts reaches the engine complete explosion speed for the first time after 0.5 seconds. Meanwhile, the hydraulic control valves 29 and 31 are closed. Therefore, the generation of abnormal noise can be prevented more reliably, and the reliability of the chain tensioner 23 can be more reliably ensured.
[0067]
  The chain abnormality detection device 51 determines that the chain is in an abnormal state when the actual error value Δa becomes equal to or greater than the target value ΔA. That is, the chain abnormality detection device 51 determines whether or not the chain is in an abnormal state based on the actual error value Δa that is closely related to the occurrence of abnormal noise. Therefore, the chain abnormality detection device 51 can appropriately determine whether or not the chain is in an abnormal state by using the crankshaft sensor 45 and the cam angle sensor 47 that are control devices of the variable valve timing mechanism. Therefore, the reliability of the chain tensioner 23 can be reliably ensured without deteriorating the reliability of the variable valve timing mechanisms 37 and 39.
[0068]
  In addition, when the elapsed time from the engine stop measured by the timing device 53 is 16 hours or longer after storing the information on the abnormal state of the chain, the first engine start after the engine stop is performed. Then, the hydraulic control valves 29 and 31 are closed. That is, the supply of hydraulic oil to the variable valve timing mechanisms 37 and 39 is stopped only when the possibility of abnormal noise is higher and the remaining amount of hydraulic oil in the oil passage 41 is small. Therefore, the reliability of each variable valve timing mechanism 37, 39 can be ensured more reliably.
[0069]
  Further, since the control device 61 controls the intake side hydraulic control valve 29 and the exhaust side hydraulic control valve 31, when the engine is started after storing the information on the abnormal state of the chain, any of the hydraulic control valves 29, 31 is selected. Is closed for a predetermined period. That is, the supply of hydraulic oil is stopped for both the variable valve timing mechanisms 37 and 39. Therefore, in the variable valve timing device 43 of the engine in which abnormal noise is likely to occur, the reliability of the chain tensioner 23 can be ensured without impairing the reliability of the variable valve timing mechanisms 37 and 39.
[0070]
  In this embodiment, the timer is turned off when it is determined that 0.5 seconds have passed since the timer was turned on. However, the timer is turned on for 0.5 to 1.0 seconds after the timer is turned on. The timer may be turned off when the time in the range has elapsed.
[0071]
  (Other embodiments)
  the aboveEmbodimentThen, when the flag f is 1, the duty ratio of the hydraulic control valve 29 is set to 0% after being set to 50%, but may be set to 100% after the duty ratio of the hydraulic control valve 29 is set to 50%.
[0072]
  Also, aboveEmbodimentThen, when the flag f is 0, the duty ratio of the hydraulic control valve 29 is set to 0%, but the duty ratio of the hydraulic control valve 29 may be set to 100%.
[0073]
  Also, aboveEmbodimentThen, the time determination unit 61b determines whether or not the elapsed time from the engine stop measured by the time measuring device 53 is 16 hours or more. The time determination unit 61b measures the time by the time measuring device 53. It may be determined whether the elapsed time from the engine stop to the first engine start after the engine stop is 16 hours or more.
[Brief description of the drawings]
FIG. 1 is a route diagram of a lubrication system mechanism according to an embodiment.
FIG. 2 is a block diagram of a variable valve timing device for an engine according to the embodiment.
FIG. 3 is a flowchart showing the operation of the variable valve timing device for the engine according to the embodiment.
FIG. 4 is a diagram showing a relationship between engine speed and time according to the embodiment.
[Explanation of symbols]
  7 Oil pump
  13 Crankshaft
  23 Hydraulic chain tensioner
  29, 31 Hydraulic control valve
  33, 35 Camshaft
  37, 39 Variable valve timing mechanism
  41 Oilway
  45 Crankshaft sensor (relative phase detection means)
  47 Cam angle sensor (relative phase detection means)
  51 Chain abnormality detection device (abnormality determination means)
  55 Engine speed sensor
  61 Control device (control means)

Claims (5)

A hydraulic variable valve timing mechanism that is provided between the camshaft and a sprocket located at the end of the camshaft and can change the valve timing, and a hydraulic pressure that controls the hydraulic pressure supplied to the variable valve timing mechanism A control valve, a hydraulic chain tensioner that applies tension to the chain spanned between the sprocket and the crankshaft, and the chain tensioner, the hydraulic control valve, and the variable valve timing mechanism are arranged in this order from the upstream side. And an engine variable valve timing device comprising an oil passage through which oil discharged from the oil pump flows,
An abnormality determining means for determining whether or not the chain is in an abnormal state;
Storage means for storing information on the abnormal state when the abnormality determining means determines that the chain is in an abnormal state;
A variable valve timing apparatus for an engine, comprising: control means for closing the hydraulic control valve for a predetermined period when the engine is started after storing the abnormal state information by the storage means. The variable valve timing apparatus for an engine according to claim 1 ,
Equipped with elapsed time measuring means to measure the elapsed time from engine stop,
The control means, after the storage of the abnormal state information by the storage means and when the elapsed time from the engine stop measured by the elapsed time measurement means is equal to or longer than a set time, An engine variable valve timing device configured to close the hydraulic control valve for a predetermined period when the engine is first started. The variable valve timing apparatus for an engine according to claim 1 or 2 ,
The variable valve for an engine is characterized in that the predetermined period is between a starter start time and a time when a predetermined time has elapsed after the engine speed after the starter start reaches the engine complete explosion speed for the first time. Timing device. The variable valve timing device for an engine according to any one of claims 1 to 3 ,
The variable valve timing mechanism includes an intake camshaft variable valve timing mechanism and an exhaust camshaft variable valve timing mechanism,
The hydraulic control valve includes an intake camshaft hydraulic control valve that controls the hydraulic pressure supplied to the intake camshaft variable valve timing mechanism and an exhaust camshaft that controls the hydraulic pressure supplied to the exhaust camshaft variable valve timing mechanism. For hydraulic control valve and
The variable valve timing apparatus for an engine, wherein the control means controls the intake camshaft hydraulic control valve and the exhaust camshaft hydraulic control valve. The variable valve timing device for an engine according to any one of claims 1 to 4,
The variable valve timing apparatus for an engine according to claim 1, wherein the abnormality determining means is configured to determine that the chain is in an abnormal state when the chain elongation exceeds a predetermined elongation amount.

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