JP2004332625A - Variable valve timing device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure reliability of a chain tensioner without impairing reliability of a variable valve timing mechanism, in a variable valve timing device for an engine, equipped with the hydraulic variable valve timing mechanism, a hydraulic control valve, the hydraulic chain tensioner, and an oil path. <P>SOLUTION: The variable valve timing device for an engine, comprises; the variable valve timing mechanism; the hydraulic control valve; the oil path; a chain abnormality detecting device detecting an abnormal state of a chain; and a control device controlling the hydraulic control valve. When an abnormal state of the chain is determined by the chain abnormality detecting device, a memory part of the control device stores information on the abnormal state, and a flag becomes 1. In the case where the flag is 1 and it is determined that a starter is in an ON state, the control device controls a duty ratio of the hydraulic control valve to become 0% to close the hydraulic control valve. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an engine variable valve timing device capable of changing the opening and closing timing of an engine valve.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an engine variable valve timing device capable of changing the opening and closing timing of an engine valve has been known (for example, refer to Patent Document 1). The 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 for controlling the hydraulic pressure supplied to the variable valve timing mechanism, and a variable valve timing mechanism. And an oil passage through which the supplied hydraulic oil flows. The hydraulic pressure supplied to the advance hydraulic chamber and the retard hydraulic chamber of the variable valve timing mechanism is controlled by a hydraulic control valve, so that the relative phase of the camshaft with respect to the crankshaft is changed to open and close the valve. change.
[0003]
Further, 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, it is difficult for the hydraulic pressure to quickly act on devices other than the variable valve timing mechanism. . Therefore, for example, an attempt has been made to improve the discharge characteristics of an oil pump to suppress the possibility that the above-described variable valve timing mechanism may cause adverse effects.
[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 in an engine used for a long period of time, an abnormal noise such as jarring is generated after the engine completely explodes when the engine is started. Here, "complete explosion" means a state in which all of the cylinders arranged in the engine have exploded.
[0006]
Therefore, the present inventors have conducted various studies to determine 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 generation of the abnormal sound, a chain extending over the crankshaft and the camshaft and a hydraulic chain tensioner provided upstream of the variable valve timing mechanism and applying tension to the chain are used. It turned out that the relationship was raised. Specifically, the chain that has been extended over many years of use and the arm of the chain tensioner that lacks hydraulic pressure during the engine start process flutter at a low cycle when the engine speed is low, and after the engine complete explosion, When the engine speed increased, the fluttering was reproduced in a high cycle, and an abnormal sound was generated.
[0007]
In addition, various tests were conducted to determine the conditions under which this phenomenon is likely to occur.As a result, when the elongation of the chain exceeds a predetermined amount of elongation, it easily occurs. It was found that the possibility of occurrence was high. Furthermore, it was found that this phenomenon occurred in a specific engine.
[0008]
The generation of this abnormal sound may not only impair the merchantability of the engine, but also impair the reliability of the chain tensioner, and is a problem to be solved.
[0009]
Here, in the variable valve timing device for an engine according to Patent Document 1, the hydraulic control valve is kept closed for a predetermined period every time the engine is started. Thus, each time the engine is started, the supply of oil to the variable valve timing mechanism is stopped for a predetermined period, and the oil is more quickly supplied to the lubrication-required parts such as the connecting rod and the crankshaft. Therefore, it is possible to prevent abnormal noise from being generated at the above-described portion due to insufficient lubrication when the engine is started. However, in this variable valve timing device for an engine, there is no intention regarding the elongation of the chain which is the cause of the problem of the present invention, and regardless of whether the possibility of occurrence of abnormal noise is high or low, the hydraulic control valve Is closed, the reliability of the variable valve timing mechanism may be impaired.
[0010]
The present invention has been made in view of the above circumstances, and has as its object to provide a hydraulic variable valve timing mechanism capable of changing valve timing, and a hydraulic pressure for controlling hydraulic pressure supplied to the variable valve timing mechanism. In a variable valve timing device for an engine including a control valve, a hydraulic chain tensioner, and an oil path in which the chain tensioner, the hydraulic control valve, and the variable valve timing mechanism are disposed, the engine may have a variable valve timing device. It is an object of the present invention to appropriately prevent the generation 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]
A first invention is provided between a camshaft and a sprocket located at an end of the camshaft, and is provided with a hydraulic variable valve timing mechanism capable of changing a valve timing, and supplying the variable valve timing mechanism to the variable valve timing mechanism. A hydraulic control valve for controlling a hydraulic pressure to be applied, a hydraulic chain tensioner for applying tension to a chain spanned between the sprocket and the crankshaft, and the chain tensioner, the hydraulic control valve, and the variable valve in order from the upstream side. A variable valve timing device for an engine provided with a timing mechanism and an oil passage through which oil discharged from an oil pump flows, wherein abnormality determining means for determining whether 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; 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]
Here, the “abnormal state of the chain” refers to, for example, a state where the elongation of the chain is equal to or more than a predetermined amount of elongation.
[0013]
Thereby, when the engine is started after the information on the abnormal state of the chain is stored, 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, at the time of starting the engine, oil is more quickly supplied to the chain tensioner. Therefore, the hydraulic pressure in the chain tensioner quickly rises, and the rattling of the chain can be prevented. Therefore, it is possible to prevent the occurrence of abnormal noise when the engine is started, and it is possible to ensure the reliability of the chain tensioner.
[0014]
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, when the possibility of occurrence of abnormal noise at the time of starting the engine is low, oil is supplied to the variable valve timing mechanism. 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.
[0015]
As described above, the reliability of the chain tensioner can be secured without impairing the reliability of the variable valve timing mechanism.
[0016]
In a second aspect based on the first aspect, there is provided a relative phase detecting means for detecting a relative phase of the camshaft with respect to a reference position of the crankshaft, wherein the abnormality determining means is detected by the relative phase detecting means. The chain is determined to be in an abnormal state when the difference between the relative phase and the reference relative phase of the camshaft with respect to the reference position of the crankshaft is equal to or greater than a predetermined value. It is assumed that.
[0017]
By the way, when the chain elongates due to long-term use or the like, the relative phase of the camshaft with respect to the reference position of the crankshaft changes. When the elongation of the chain is equal to or more than a predetermined elongation, an abnormal sound is likely to be generated. From the above, it can be seen that the change in the relative phase and the occurrence of the abnormal sound have a close relationship.
[0018]
Here, according to the present invention, the abnormality determining means determines that the chain is in an abnormal state when the deviation between the detected relative phase and the reference relative phase is equal to or greater than a predetermined value. That is, the abnormality determining means determines whether or not the chain is in an abnormal state based on a change in the relative phase closely related to the generation of the abnormal sound. Therefore, the abnormality determination means can appropriately determine whether the chain is in an abnormal state by using the control device of the variable valve timing mechanism. Therefore, the reliability of the chain tensioner can be reliably ensured without reliably impairing the reliability of the variable valve timing mechanism.
[0019]
According to a third invention, in the second invention, a learning means for learning the deviation when the deviation between the relative phase detected by the relative phase detection means and the reference relative phase is smaller than the predetermined value. And an addition value storage means for cumulatively adding the deviation and storing the cumulative addition value, wherein the abnormality determination means determines that the cumulative addition value stored by the addition value storage means is equal to or greater than the predetermined value. Sometimes, the chain is determined to be in an abnormal state.
[0020]
Thus, the abnormality determining means determines that the chain is in an abnormal state when the stored cumulative value becomes equal to or greater than the predetermined value. That is, the abnormality determining means determines whether or not the chain is in an abnormal state based on a change in the relative phase closely related to the generation of the abnormal sound. Therefore, the abnormality determination means can appropriately determine whether the chain is in an abnormal state by using the control device of the variable valve timing mechanism. Therefore, the reliability of the chain tensioner can be reliably ensured without reliably impairing the reliability of the variable valve timing mechanism.
[0021]
According to a fourth aspect of the present invention, in any one of the first to third aspects, further comprising an elapsed time measuring means for measuring an elapsed time from an engine stop, wherein the control means is configured to detect the abnormal state by the storage means. After storing the information and when the elapsed time from the engine stop measured by the elapsed time measuring means is equal to or longer than a set time, if the first engine start after the engine stop is performed, the predetermined period The hydraulic control valve is configured to be closed.
[0022]
By the way, the longer the elapsed time from the stop of the engine to the first start of the engine after the stop of the engine, the smaller the remaining amount of the oil in the oil passage. Further, the smaller the remaining amount of the oil in the oil passage, the more easily the abnormal sound is generated.
[0023]
Here, according to the present invention, after the storage of the abnormal state information by the storage unit and when the elapsed time from the stop of the engine measured by the elapsed time measurement unit is equal to or longer than the set time, When the engine is first started, the hydraulic control valve is closed for a predetermined period. That is, the supply of the oil to the variable valve timing mechanism is stopped only when the possibility of occurrence of the abnormal sound is higher and the remaining amount of the oil in the oil passage is small. Therefore, the reliability of the variable valve timing mechanism can be more reliably ensured.
[0024]
In a fifth aspect based on any one of the first to fourth aspects, the predetermined period is at the time of starter start and when the engine speed after the starter reaches the engine complete explosion speed for the first time. From the time when a predetermined time has elapsed since the start of the operation.
[0025]
Here, the “engine complete explosion rotation speed” refers to the rotation speed of the engine when all the cylinders arranged in the engine explode.
[0026]
By the way, between the time when the starter is started and the time when a predetermined time has elapsed from the time when the engine speed after the starter started reaches the engine complete explosion speed for the first time, is a time zone in which abnormal sound is likely to occur. I know it.
[0027]
Here, according to the present invention, a time period in which abnormal sound is likely to occur, that is, a predetermined time has elapsed since the start of the starter and from when the engine speed after the starter reached the engine complete explosion speed for the first time. In between, the hydraulic control valve is closed. Therefore, occurrence of abnormal noise can be more reliably prevented, and the reliability of the chain tensioner can be more reliably ensured.
[0028]
In a sixth aspect based on any one of the first to fourth aspects, the predetermined period is from an engine start-up time to an engine speed reduction area after the first complete engine explosion after the starter start-up. It is characterized in that it is until the engine speed becomes equal to or lower than a predetermined speed.
[0029]
Here, "complete explosion" means a state in which all of the cylinders arranged in the engine have exploded.
[0030]
By the way, during the period from the start of the starter to the time when the engine speed becomes equal to or less than the predetermined speed in the engine speed reduction region after the first complete engine explosion after the starter start, an abnormal sound is easily generated. I know that
[0031]
Here, according to the present invention, the engine speed is set to a predetermined value in a time zone in which an abnormal sound is likely to be generated, that is, in a region where the engine speed is reduced after the first complete engine explosion after the starter is started. The hydraulic control valve is closed until the number becomes equal to or less than the number. Therefore, occurrence of abnormal noise can be more reliably prevented, and the reliability of the chain tensioner can be more reliably ensured.
[0032]
In a seventh aspect based on any one of the first to sixth aspects, the variable valve timing mechanism includes a variable valve timing mechanism for an intake camshaft and a variable valve timing mechanism for an exhaust camshaft. The hydraulic control valve includes an intake camshaft hydraulic control valve that controls hydraulic pressure supplied to the intake camshaft variable valve timing mechanism, and an exhaust cam that controls hydraulic pressure supplied to the exhaust camshaft variable valve timing mechanism. A hydraulic control valve for the shaft, and the control means controls the hydraulic control valve for the intake camshaft and the hydraulic control valve for the exhaust camshaft.
[0033]
Incidentally, a variable valve timing mechanism for the intake camshaft and a variable valve timing mechanism for the exhaust camshaft are provided as the variable valve timing mechanisms, and a hydraulic control valve for the intake camshaft and a hydraulic control valve for the exhaust camshaft are provided as the hydraulic control valves. It has been found that the variable valve timing device of the engine provided has a tendency to generate abnormal noise.
[0034]
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, the intake means Both the camshaft and exhaust camshaft hydraulic control valves are closed for a predetermined period. That is, the supply of oil to both the intake camshaft and exhaust camshaft variable valve timing mechanisms is stopped. Therefore, in a variable valve timing device of an engine in which an abnormal sound is likely to be generated, the reliability of the chain tensioner can be secured without deteriorating the reliability of the variable valve timing mechanism.
[0035]
【The invention's effect】
According to the first aspect, the oil pressure control valve is closed for a predetermined period when the engine is started after the information on the abnormal state of the chain is stored, so that the supply of oil to the variable valve timing mechanism having a relatively large capacity is performed. Is stopped. Therefore, at the time of starting the engine, the oil is more quickly supplied to the chain tensioner, the oil pressure in the chain tensioner rises quickly, and the rattling of the chain can be prevented. Therefore, it is possible to prevent the occurrence of abnormal noise when the engine is started, and it is possible to ensure the reliability of the chain tensioner. 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, when the possibility of occurrence of abnormal noise at the time of starting the engine is low, oil is supplied to the variable valve timing mechanism. 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 secured without impairing the reliability of the variable valve timing mechanism.
[0036]
According to the second aspect, the abnormality determining means determines that the chain is in an abnormal state when the deviation between the detected relative phase and the reference relative phase is equal to or greater than a predetermined value. That is, the abnormality determining means determines whether or not the chain is in an abnormal state based on a change in the relative phase closely related to the generation of the abnormal sound. Therefore, the abnormality determining means can appropriately determine whether or not the chain is in an abnormal state by using the control device of the variable valve timing mechanism, without reliably impairing the reliability of the variable valve timing mechanism. Thus, the reliability of the chain tensioner can be reliably ensured.
[0037]
According to the third aspect, the abnormality determining means determines that the chain is in an abnormal state when the stored cumulative value is equal to or greater than the predetermined value. That is, the abnormality determining means determines whether or not the chain is in an abnormal state based on a change in the relative phase closely related to the generation of the abnormal sound. Therefore, the abnormality determining means can appropriately determine whether or not the chain is in an abnormal state by using the control device of the variable valve timing mechanism, without reliably impairing the reliability of the variable valve timing mechanism. Thus, the reliability of the chain tensioner can be reliably ensured.
[0038]
According to the fourth aspect, after the storage of the abnormal state information by the storage unit and when the elapsed time from the engine stop measured by the elapsed time measurement unit is equal to or longer than the set time, the time after the stop of the engine is determined. When the engine is first started, the hydraulic control valve is closed for a predetermined period. That is, the supply of the oil to the variable valve timing mechanism is stopped only when the possibility of occurrence of the abnormal sound is higher and the remaining amount of the oil in the oil passage is small. Therefore, the reliability of the variable valve timing mechanism can be more reliably ensured.
[0039]
According to the fifth aspect of the invention, the predetermined time has elapsed from the time when the abnormal sound is likely to occur, that is, the time when the starter is started and the time 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, occurrence of abnormal noise can be more reliably prevented, and the reliability of the chain tensioner can be more reliably ensured.
[0040]
According to the sixth aspect, in a time zone in which abnormal sound is likely to occur, that is, in a region where the engine speed is reduced to a predetermined value in an engine speed reduction region after the first complete engine explosion after the starter is started. The hydraulic control valve is closed until the number becomes equal to or less than the number. Therefore, occurrence of abnormal noise can be more reliably prevented, and the reliability of the chain tensioner can be more reliably ensured.
[0041]
According to the seventh aspect, the control means controls the intake camshaft hydraulic control valve and the exhaust camshaft hydraulic control valve. Both the camshaft and exhaust camshaft hydraulic control valves are closed for a predetermined period. That is, the supply of oil to both the intake camshaft and exhaust camshaft variable valve timing mechanisms is stopped. Therefore, in a variable valve timing device of an engine in which an abnormal sound is likely to be generated, the reliability of the chain tensioner can be secured without deteriorating the reliability of the variable valve timing mechanism.
[0042]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0043]
As shown in FIG. 1, the 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, 31, intake and exhaust camshafts 33, 35, hydraulic intake and exhaust side variable valve timing mechanism (VVT) 37, 39 and an oil passage 41. Note that the variable valve timing mechanisms for the intake camshaft and the exhaust camshaft according to the present invention correspond to the intake-side and exhaust-side variable valve timing mechanisms 37 and 39, respectively. These correspond to the intake side and exhaust side hydraulic control valves 29 and 31, respectively.
[0044]
The oil pump 7 is a device that sucks hydraulic oil stored in the oil pan 3 and discharges the sucked hydraulic oil using the rotation of the crankshaft 13 as power.
[0045]
The chain tensioner 23 is a device that applies hydraulic pressure to a chain wound around a sprocket located at an end of each of the camshafts 33 and 35 and a sprocket of the crankshaft 13.
[0046]
The intake and exhaust camshafts 33, 35 are arranged parallel to the crankshaft 13. Each of the camshafts 33 and 35 has a plurality of cams fixedly mounted thereon. A sprocket is provided near one end of each of the camshafts 33 and 35.
[0047]
The intake-side and exhaust-side variable valve timing mechanisms 37 and 39 are provided between intake and exhaust camshafts 33 and 35 and sprockets located at ends of the camshafts 33 and 35, respectively. These variable valve timing mechanisms 37, 39 change the rotational phase angles of the intake and exhaust camshafts 33, 35 with respect to the crankshaft 13, respectively. In other words, each of the variable valve timing mechanisms 37 and 39 changes 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 advance and retard hydraulic chambers. When switching the opening / closing timing of the valve from the advance side to the retard side, the hydraulic pressure is supplied to the advance hydraulic chamber and the hydraulic oil in the retard hydraulic chamber is discharged, while the valve open / close timing is advanced from the retard side. When switching to the corner side, the hydraulic oil is supplied to the retard hydraulic chamber and the hydraulic oil in the advance hydraulic chamber is simultaneously discharged.
[0048]
The intake-side and exhaust-side hydraulic control valves 29, 31 are valves for controlling the hydraulic pressure supplied to the advance and retard hydraulic chambers of the intake-side and exhaust-side variable valve timing mechanisms 37, 39, respectively. Each of the hydraulic control valves 29 and 31 includes a hollow valve case, a spool movable in the valve case in the axial direction, and a spring for urging 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 supply oil 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 source pressure from a hydraulic source to each of the hydraulic control valves 29 and 31. The advancing and retarding oil passages are passages for supplying advancing and retarding hydraulic pressures to the advancing and retarding 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.
[0049]
The amount of movement of the spool in the axial direction is adjusted by a solenoid that is duty-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. I do. When the solenoid is in the excited state (for example, duty ratio = 100%), the spool moves downward, and the retard oil passage and the hydraulic supply oil passage communicate with each other via the input port. Further, when the solenoid is set to a state in which 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 are provided. It does not communicate with the road.
[0050]
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, intake and exhaust camshafts 33 and 35, an intake side and an exhaust side. This is a single-system passage for supplying the hydraulic oil of the oil pan 3 to the variable valve timing mechanisms 37, 39 and the like. In the oil passage 41, 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, respective hydraulic control valves 29 and 31, and respective camshafts are arranged in this order from the upstream side. 33 and 35 and variable valve timing mechanisms 37 and 39 are provided.
[0051]
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 and 39 and the intake side and exhaust side hydraulic control valves 29 and 31. An advancing and retarding oil passage which is a part of the oil passage 41, a crankshaft sensor 45 for detecting a reference position of the crankshaft, and detecting a relative phase of the camshaft with respect to the reference position of the crankshaft. A cam angle sensor 47, a learning device 49, a chain abnormality detecting device 51 for detecting an abnormal state of the chain, a time measuring device 53 for measuring time, an engine speed sensor 55 for detecting the engine speed, and a 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 a starting device for the engine. 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 corresponds to This corresponds to the learning device 49.
[0052]
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 a part of a device that controls each of the variable valve timing mechanisms 37 and 39.
[0053]
The learning device 49 is connected to a change value storage section 51 a (additional value storage means) (the details of the change value storage section 51 a will be described later) and a control device 61. The learning device 49 learns and corrects the phase shift amount Δa1 when it is determined that the phase shift amount Δa1 is equal to or greater than the target shift amount ΔA1 and smaller than the target value ΔA (phase shift amount Δa1, target shift amount). The details of the amount ΔA1 and the target value ΔA will be described later).
[0054]
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 elongation of the chain becomes equal to or greater than a predetermined amount of elongation (the details of a method of determining an abnormal state of the chain will be described later). The chain abnormality detecting device 51 has a built-in change value storage unit 51a. When the learning device 49 determines that the phase shift amount Δa1 is equal to or larger than the target shift amount ΔA1 and smaller than the target value ΔA, the change value storage unit 51a stores the phase shift amount Δa1 in the stored cumulative addition value. The cumulative addition is performed, and the new cumulative addition value is stored. Here, the “stored cumulative addition value” is a value obtained by cumulatively adding the phase shift amount Δa1 that is greater than or equal to the target shift amount ΔA1 and that is smaller than the target value ΔA, which is stored in the change value storage unit 51a. .
[0055]
The timing device 53 is connected to a timing determination unit 61b 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.
[0056]
The control device 61 is a device that duty-controls the solenoids of the intake-side and exhaust-side hydraulic control valves 29 and 31. The control device 61 has a built-in storage unit 61a and a time determination unit 61b. When the chain abnormality detecting device 51 determines that the chain is in an abnormal state, the storage unit 61a stores information on the abnormal state. The timing determination unit 61b determines whether the elapsed time from the stop of the engine, measured by the timing device 53, is equal to or longer than a predetermined time (for example, 16 hours in the present embodiment). In other words, the timing determination unit 61b determines whether the remaining amount of the hydraulic oil in the oil passage 41 is smaller than a predetermined amount. The elapsed time measuring means according to the present invention corresponds to the clock device 53.
[0057]
-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 (the details of the flag f will be described later) is 1, will be described with reference to FIGS. In the following description, only control of the intake-side hydraulic control valve 29 by the control device 61 is described, and control of the exhaust-side hydraulic control valve 31 is omitted.
[0058]
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, it indicates that the chain is in an abnormal state. Indicates that the chain is not abnormal.
[0059]
When it is determined that the flag f = 1, the process proceeds to step S2, and the timing determination unit 61b of the control device 61 determines whether the elapsed time from the previous stop of the engine is 16 hours or more.
[0060]
When it is determined that the elapsed time is 16 hours or more, the process proceeds to step S3, and the control device 61 determines whether the starter 60 is in the ON state. That is, the control device 61 determines whether or not the starter 60 has started.
[0061]
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, but other devices other than the intake-side variable valve timing mechanism 37, such as the chain tensioner 23. Is supplied with hydraulic oil.
[0062]
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 arranged in the engine have exploded. The “engine complete explosion speed” refers to the engine speed at the time of the engine complete explosion, and is generally smaller than the idle speed (for example, 600 rpm). In the present embodiment, the engine complete explosion rotation speed N1 is, for example, 500 rpm.
[0063]
When it is determined that the current engine speed Ne is equal to or greater than 500 rpm, the timer is turned on (step S6).
[0064]
Next, the control device 61 determines whether or not a predetermined time (for example, 0.5 seconds in the present embodiment) has elapsed since the timer was turned on (step S7).
[0065]
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 control device 61 operates the solenoid so that the duty ratio of the hydraulic control valve 29 becomes 0%. Control is performed (step S9). Thereby, the advance angle passage corresponding to the intake side valve timing mechanism 37 and the hydraulic supply oil passage communicate with each other. At this time, the hydraulic oil starts to be supplied to the advance hydraulic chamber through the hole formed in the advance passage and the intake camshaft 33. The hydraulic oil previously stored in the retard hydraulic chamber starts returning to the oil pan 3 by receiving the hydraulic pressure from the advance hydraulic chamber.
[0066]
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 coolant temperature sensor 59, for example. As a result, the output performance of the engine and the like are optimized.
[0067]
Next, the chain abnormality detecting device 51 determines whether or not the chain is in an abnormal state. Specifically, first, the learning device 49 determines whether the phase shift amount Δa1 is equal to or larger than the target shift amount ΔA1 and smaller than the target value ΔA (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 shift amount ΔA1” is a small-unit target shift amount that derives a phase shift amount that gradually progresses over many years. The “target value ΔA” is a value corresponding to an elongation amount slightly smaller than the elongation amount of the chain which is likely to cause abnormal noise, which is obtained by an experiment conducted in advance. The target value ΔA is larger than the target deviation amount ΔA1.
[0068]
When it is determined that the phase shift amount Δa1 is equal to or larger than the target shift amount ΔA1 and smaller than the target value ΔA, the change value storage unit 51a adds the phase shift amount Δa1 to the stored cumulative value, and adds the added value. The obtained cumulative addition value is stored (step S11). At this time, the learning device 49 simultaneously learns and corrects the phase shift amount Δa1.
[0069]
Next, the chain abnormality detecting device 51 determines whether or not the accumulated value, that is, the actual error value Δa has become equal to or larger 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 detecting device 51 determines that the chain is in an abnormal state, and sends 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), and thereby the flag f becomes 1 (step S14). When the phase shift amount Δa1 becomes equal to or larger than the target value ΔA, the chain abnormality detecting device 51 determines that the chain is in an abnormal state. Thereafter, this routine ends.
[0070]
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 becomes 0.
[0071]
<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.
[0072]
The control device 61 determines whether or not the flag f is 1 (step S1).
[0073]
If it is determined that the flag f is not 1, the process proceeds to step S15, and the control device 61 determines whether the starter 60 is in the ON state.
[0074]
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). Thereby, the advance passage corresponding to the intake-side variable valve timing mechanism 37 and the hydraulic supply oil passage communicate with each other, and the hydraulic oil is supplied to the advance hydraulic chamber and stored in the retard hydraulic chamber in advance. The operating oil returns to the oil pan 3.
[0075]
Next, the hydraulic control valve 29 is controlled based on the operating state of the engine detected by the various sensors 55, 57, 59. The following steps are almost the same as the steps in the case where the flag f = 1.
[0076]
The control of the exhaust-side hydraulic control valve 31 by the control device 61 is performed in the same manner as the control of the intake-side hydraulic control valve 29.
[0077]
As described above, according to the present embodiment, when the engine is started after the storage unit 61a stores the information on the abnormal state of the chain, the hydraulic control valves 29 and 31 are closed for a predetermined period, so that the capacity is relatively large. The supply of the hydraulic oil to the variable valve timing mechanisms 37 and 39 is stopped. Therefore, at the time of starting the engine, the hydraulic oil is supplied to the chain tensioner 23 more quickly. Therefore, the hydraulic pressure in the chain tensioner 23 rises quickly, and the rattling of the chain can be prevented. Therefore, occurrence of abnormal noise at the time of engine start can be prevented, and reliability of the chain tensioner 23 can be secured. When the chain abnormality detecting device 51 determines that the chain is not abnormal, 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 when starting the engine is low, hydraulic oil is supplied to each of the variable valve timing mechanisms 37 and 39. Therefore, the supply of the hydraulic oil to each of the variable valve timing mechanisms 37 and 39 is not stopped every time the engine is started, so that the reliability of each 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 each of the variable valve timing mechanisms 37 and 39.
[0078]
In addition, the time period in which abnormal sound is likely to occur, that is, the time when the starter 60 is started and the time when 0.5 seconds have elapsed since the engine speed after the starter 60 started reaches the engine complete explosion speed for the first time. During this time, each hydraulic control valve 29, 31 is closed. Therefore, occurrence of abnormal noise can be more reliably prevented, and the reliability of the chain tensioner 23 can be more reliably ensured.
[0079]
Further, the chain abnormality detecting device 51 determines that the chain is in an abnormal state when the actual error value Δa becomes equal to or larger 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 closely related to the occurrence of the abnormal sound. Therefore, the chain abnormality detecting 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 reliably impairing the reliability of each of the variable valve timing mechanisms 37 and 39.
[0080]
Further, when the information on the abnormal state of the chain is stored and the elapsed time from the stop of the engine measured by the timer 53 is 16 hours or more, the first engine start after the stop of the engine is performed. Then, the hydraulic control valves 29 and 31 are closed. That is, the supply of the hydraulic oil to each of the variable valve timing mechanisms 37 and 39 is stopped only when the possibility of occurrence of the abnormal sound is higher and the remaining amount of the hydraulic oil in the oil passage 41 is small. Therefore, the reliability of each of the variable valve timing mechanisms 37 and 39 can be more reliably ensured.
[0081]
Further, since the control device 61 controls the intake-side hydraulic control valve 29 and the exhaust-side hydraulic control valve 31, when starting the engine after storing the information on the abnormal state of the chain, any one of the hydraulic control valves 29, 31 is used. Are closed for a predetermined period. That is, the supply of the hydraulic oil to both the variable valve timing mechanisms 37 and 39 is stopped. Therefore, in the variable valve timing device 43 of the engine in which the abnormal sound is likely to be generated, the reliability of the chain tensioner 23 can be secured without deteriorating the reliability of each variable valve timing mechanism 37, 39.
[0082]
In the present embodiment, the timer is turned off when it is determined that 0.5 seconds have elapsed since the timer was turned on. The timer may be turned off when the time in the range has elapsed.
[0083]
(Embodiment 2)
In the present embodiment, when the flag f is 1, from the start of the starter 60 until the engine speed becomes equal to or lower than the predetermined engine speed in the engine speed reduction region after the first complete engine explosion after the starter 60 starts. During this period, the duty ratio of each hydraulic control valve 29, 31 is set to 50%. Other points are almost the same as the first embodiment.
[0084]
-Operation of variable valve timing device-
Here, the operation of the variable valve timing device 43 for the engine according to the present embodiment when the flag f is 1 will be described with reference to FIGS. 1, 2, and 5. FIG. In the following description, steps different from those in the first embodiment are mainly described.
[0085]
After controlling the solenoid so that the duty ratio of the hydraulic control valve 29 becomes 50%, the control device 61 determines whether or not it is in the engine speed reduction region (step S17). Here, the “engine speed reduction region” is a region in which the engine speed has decreased after the complete combustion of the engine (see FIG. 6).
[0086]
When it is determined that the engine speed is in the engine speed reduction region, the control device 61 determines whether or not the current engine speed Ne has become equal to or lower than the predetermined engine speed N2 (step S18). In the present embodiment, the predetermined engine speed N2 is, for example, 1800 rpm.
[0087]
When it is determined that the current engine speed Ne has become 1800 rpm or less, the control device 61 controls the solenoid so that the duty ratio of the hydraulic control valve 29 becomes 0% (step S9).
[0088]
As described above, according to the present embodiment, the engine speed Ne in the time zone where the abnormal sound is likely to occur, that is, in the engine speed reduction region after the start of the starter 60 and after the first complete engine explosion after the starter 60 starts. Is reduced to 1800 rpm or less, the hydraulic control valves 29 and 31 are closed. Therefore, occurrence of abnormal noise can be more reliably prevented, and the reliability of the chain tensioner 23 can be more reliably ensured.
[0089]
In the present embodiment, the predetermined engine speed N2 is 1800 rpm, but is not limited thereto and may be another value.
[0090]
(Other embodiments)
In the above embodiments, when the flag f is 1, the duty ratio of the hydraulic control valve 29 is set to 50% and then to 0%. However, the duty ratio of the hydraulic control valve 29 is set to 50% and then set to 100%. Is also good.
[0091]
In the above embodiments, when the flag f is 0, the duty ratio of the hydraulic control valve 29 is set to 0%. However, the duty ratio of the hydraulic control valve 29 may be set to 100%.
[0092]
In each of the above embodiments, the timing determination unit 61b determines whether or not the elapsed time from the stop of the engine, measured by the timing device 53, is 16 hours or more. Alternatively, it may be determined whether the elapsed time from the stop of the engine to the first start of the engine after the stop of the engine, measured by the timer 53, is 16 hours or more.
[Brief description of the drawings]
FIG. 1 is a path diagram of a lubrication system mechanism according to an embodiment.
FIG. 2 is a block diagram of an engine variable valve timing device according to the embodiment.
FIG. 3 is a flowchart illustrating an operation of the variable valve timing device for the engine according to the embodiment.
FIG. 4 is a diagram illustrating a relationship between an engine speed and time according to the embodiment.
FIG. 5 is a flowchart showing an operation of the engine variable valve timing device according to the embodiment.
FIG. 6 is a diagram illustrating a relationship between an 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 detecting 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 (7)

A hydraulic variable valve timing mechanism provided between the camshaft and a sprocket located at an end of the camshaft and capable of changing valve timing; and a hydraulic pressure for controlling a 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 order from the upstream side. And an oil passage through which the oil discharged from the oil pump flows.
Abnormality determining means for determining whether the chain is in an abnormal state;
Storage means for storing information on the abnormal state when the chain is determined to be abnormal by the abnormality determining means;
Control means for closing the hydraulic control valve for a predetermined period when the engine is started after the storage of the abnormal state information by the storage means. The variable valve timing device for an engine according to claim 1,
Relative phase detecting means for detecting a relative phase of the camshaft with respect to a reference position of the crankshaft,
The abnormality determining means is configured to determine that the chain is in an abnormal state when a deviation between a relative phase detected by the relative phase detecting means and a reference relative phase of the camshaft with respect to a reference position of the crankshaft is equal to or greater than a predetermined value. A variable valve timing device for an engine, characterized in that the variable valve timing device is configured to determine that: The variable valve timing device for an engine according to claim 2,
Learning means for learning the deviation, when a deviation between the relative phase detected by the relative phase detection means and the reference relative phase is smaller than the predetermined value,
Cumulatively adding the deviation, and an addition value storage means for storing the cumulative addition value,
The abnormality determining means is configured to determine that the chain is in an abnormal state when the cumulative addition value stored by the addition value storage means becomes equal to or greater than the predetermined value. Variable valve timing system for the engine. The variable valve timing device for an engine according to any one of claims 1 to 3,
Elapsed time measurement means for measuring the time elapsed since the engine was stopped,
The control means, after the storage of the abnormal state information by the storage means, when the elapsed time from the engine stop measured by the elapsed time measurement means is equal to or longer than a set time, after the engine stop A variable valve timing device for an engine, wherein the hydraulic control valve is closed for the predetermined period when the engine is first started. The variable valve timing device for an engine according to any one of claims 1 to 4,
The variable period of the engine, wherein the predetermined period is between a start of the starter and a period of time after a predetermined time has elapsed from when the engine rotation speed after the starter startup reaches the engine complete explosion rotation speed for the first time. Timing device. The variable valve timing device for an engine according to any one of claims 1 to 4,
The predetermined period is a period from the start of the starter to the time when the engine speed becomes equal to or lower than the predetermined speed in an engine speed reduction region after the first complete engine explosion after the starter is started. Variable valve timing system for the engine. The variable valve timing device for an engine according to any one of claims 1 to 6,
The variable valve timing mechanism includes a variable valve timing mechanism for an intake camshaft and a variable valve timing mechanism for an exhaust camshaft,
The hydraulic control valve includes an intake camshaft hydraulic control valve for controlling the hydraulic pressure supplied to the intake camshaft variable valve timing mechanism, and an exhaust camshaft for controlling the hydraulic pressure supplied to the exhaust camshaft variable valve timing mechanism. For hydraulic control valve and include
The variable valve timing device for an engine, wherein the control means controls the intake camshaft hydraulic control valve and the exhaust camshaft hydraulic control valve.

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