JP2014109237A - Chain tension control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chain tension control device of an internal combustion engine which reduces the cost of a chain tensioner by reducing the number of parts for oil leakage measures, and can exactly prevent the generation of noise and a tooth jump at the start of the internal combustion engine equipped with the chain tensioner.SOLUTION: A check valve of a chain tensioner is closed while imparting an urging force in a valve closing direction according to differential pressure to a plunger when hydraulic pressure in a hydraulic pressure chamber is higher than hydraulic pressure in an oil replenishment passage, and on the other hand, when the hydraulic pressure in the hydraulic pressure chamber is lower than the hydraulic pressure in the oil replenishment passage, the check valve is opened and connects the hydraulic chamber to the oil replenishment passage. Furthermore, a stop angle control part 51 for controlling a rotation stop angle position of a crank shaft 16 into a specified stop angle region is arranged at an engine 10, and a load applied to the plunger of the chain tensioner is controlled to a low-load side according to a stop position of the crank shaft 16.

Description

  The present invention relates to a chain tension control device for an internal combustion engine, and more particularly to a chain tension control for an internal combustion engine that controls a tension (hereinafter referred to as a tension) acting on a chain between a crankshaft and a camshaft of the internal combustion engine equipped with a chain tensioner. Relates to the device.

  In an internal combustion engine, a chain as an endless transmission element that transmits rotational power from a crankshaft to a camshaft of a valve operating mechanism is required to transmit rotation at an accurate timing without loosening. Therefore, a chain tensioner that absorbs a change in the tension of the chain due to a change in the temperature or rotation speed of the internal combustion engine or a decrease in the tension due to a secular change and keeps the tension of the chain within an appropriate range is used.

  As a conventional chain tensioner, for example, a cylinder is provided in a high pressure chamber between a tensioner housing and a plunger, so that oil introduced from the oil supply port on the tensioner housing side into the high pressure chamber via a check valve is caused by the cylinder. There is known one that can be guided to the front end side in a high-pressure chamber so as to facilitate the discharge of air in the high-pressure chamber (see, for example, Patent Document 1).

JP 2010-096339 A

  However, the conventional chain tensioner described above has a configuration in which oil in a high-pressure hydraulic chamber leaks at a predetermined flow rate from a gap between the plunger and the tensioner housing. For this reason, when the internal combustion engine is stopped in a state where a large load is applied to the chain tensioner, the oil in the high pressure portion may gradually leak to the outside or air may accumulate in the high pressure chamber.

  In such a case, the normal hydraulic reaction force from the chain tensioner cannot be obtained when the internal combustion engine equipped with the chain tensioner is restarted after being left for a long time, and the chain flutters. Or the plunger may retreat excessively, causing chain skipping.

  Alternatively, in order to suppress such abnormal noise at start-up and tooth skipping of the chain, a ratchet mechanism (back strap mechanism) that restricts the retracted amount of the plunger due to the load from the chain is provided, or air enters the high-pressure chamber It was necessary to provide a porous resin bar to reduce the amount, and the cost was high.

  Therefore, the present invention aims to reduce the cost of the chain tensioner by reducing oil leak countermeasure parts such as a ratchet mechanism and a resin bar, and to generate abnormal noise and tooth skipping at the start of the internal combustion engine equipped with the chain tensioner. An object of the present invention is to provide a chain tension control device for an internal combustion engine that can accurately prevent the above-described problem.

  In order to achieve the above object, a chain tension control device for an internal combustion engine according to the present invention includes: (1) an endless chain that is rotated and transmitted between a crankshaft and a camshaft; and a chain tensioner that adjusts the tension acting on the chain. A chain tension control device for an internal combustion engine comprising: a plunger on which a load corresponding to the tension is applied, and a hydraulic pressure that holds the plunger slidably and counters the load inside A tensioner housing that defines a hydraulic chamber that generates a reaction force, a biasing mechanism that applies a biasing force in a direction against the load to the plunger, a hydraulic pressure in the hydraulic chamber, and an oil that can supply oil to the hydraulic chamber A valve-opening state that opens and closes according to the pressure difference with the hydraulic pressure in the replenishing passage, connects the hydraulic chamber to the oil replenishing passage, and And a check valve that switches to a closed state that shuts off the chamber from the oil supply passage, and the check valve is configured so that the hydraulic pressure in the hydraulic chamber is higher than the hydraulic pressure in the oil supply passage. The valve is closed while applying an urging force in the valve closing direction corresponding to the differential pressure to the plunger, and opens when the hydraulic pressure in the hydraulic chamber is lower than the hydraulic pressure in the oil supply passage. The internal combustion engine is configured to be connected to a supply passage, and the internal combustion engine has a load that changes a rotation stop angle position of either the crankshaft or the camshaft according to the rotation stop angle position on a low load side. A stop angle control mechanism for controlling in a specific stop angle region is provided.

  With this configuration, in the present invention, the hydraulic chamber that generates the hydraulic reaction force in the chain tensioner is located on the inner back side of the tensioner housing (the inner back side of the plunger sliding hole), and the hydraulic chamber and the oil supply passage Since the check valve that can be connected is positioned on the plunger side with respect to the hydraulic chamber, it is difficult for air to enter the hydraulic chamber. Moreover, since the rotation stop angle of the crankshaft or camshaft is controlled within a specific stop angle area so that the load applied to the chain tensioner from the chain when the operation of the internal combustion engine is stopped is on the low load side, the load applied to the plunger This effectively suppresses leakage of oil in the hydraulic chamber. Therefore, it becomes possible to reduce the cost of chain tensioners by reducing the number of oil leakage countermeasure parts, and to accurately prevent the occurrence of noise and tooth skipping at the start of an internal combustion engine equipped with a chain tensioner. Become.

  In the chain tension control device for an internal combustion engine according to the present invention, (2) the stop angle control mechanism controls a rotation stop angle position of the crankshaft of the internal combustion engine within the specific stop angle region. Is good.

  With this configuration, the rotation stop angle of the crankshaft can be accurately controlled within a specific stop angle region based on the detection information of the existing crank angle sensor.

  In the chain tension control device for an internal combustion engine having the configuration of (2), (3) the stop angle control mechanism variably controls a load torque acting on the crankshaft from an auxiliary machine connected to the internal combustion engine. It should be a thing.

  In this case, by adjusting the load torque of the auxiliary machine, the load applied to the chain tensioner from the chain when the operation of the internal combustion engine is stopped can be easily and accurately controlled to the low load side, and the rotation stop angle position of the crankshaft can be controlled by the auxiliary machine load torque. It is also possible to use an existing stop control mechanism for controlling.

  In the chain tension control device for an internal combustion engine of the present invention, (4) the check valve includes a valve seat provided in the plunger so as to form a part of the oil supply passage, and the valve seat in the hydraulic chamber. And a check valve body held by the plunger so that a distance from the valve seat is limited.

  In this case, a part of the oil supply passage is formed in the plunger, and even if air is mixed into the oil supply passage, it is possible to easily secure an air vent path that does not pass through the high-pressure hydraulic chamber. Further, in a general arrangement configuration in which the outer end portion of the plunger to which the load from the chain acts is located vertically above the inner end portion that receives the hydraulic reaction force, it is difficult for air to enter the hydraulic chamber that is at a high pressure.

  In the chain tension control device for an internal combustion engine having the configuration of (4), (5) a low pressure chamber for storing the oil is formed inside the plunger while forming a part of the oil supply passage. When the load corresponding to the tension is applied to the plunger, the hydraulic chamber and the low pressure chamber may be blocked by the check valve.

  In this case, when a load corresponding to the chain tension is not applied to the plunger, even if air enters the low-pressure chamber, the air moves to the uppermost part in the low-pressure chamber, and is checked by the action of the urging means. Under the condition that the valve is opened, the oil is replenished without mixing air into the hydraulic chamber. On the other hand, when a load corresponding to the chain tension is applied to the plunger and the hydraulic pressure in the hydraulic chamber starts to rise, the check valve closes and the hydraulic chamber is shut off from the oil supply passage side, and the hydraulic pressure in the hydraulic chamber is applied to the chain tension. The corresponding high pressure will be reached quickly.

  In the chain tension control device for an internal combustion engine according to the present invention, (6) the urging mechanism is interposed between the plunger and the tensioner housing, and elastically urges the plunger constantly in a direction against the load. You may be comprised by the member.

  In this case, a simple urging mechanism can be configured, and the plunger can be incorporated into the tensioner housing in a state where the elastic member is held by the plunger in advance, and assembly can be facilitated.

  According to the present invention, the hydraulic chamber that generates the hydraulic reaction force is positioned on the inner back side of the tensioner housing to enable oil supply from the plunger side, and the load applied from the chain to the chain tensioner when the internal combustion engine is stopped. Therefore, it is possible to effectively prevent oil in the hydraulic chamber from leaking out or air from entering the hydraulic chamber due to the load applied to the plunger. As a result, it is possible to reduce the number of oil leakage countermeasure parts and reduce the cost of the chain tensioner, and to accurately prevent the occurrence of abnormal noise and tooth skipping at the start of the internal combustion engine equipped with the chain tensioner. An engine chain tension control device can be provided.

1 is a schematic configuration diagram showing an internal combustion engine and a chain tension control device thereof according to an embodiment of the present invention. It is explanatory drawing of arrangement | positioning of the chain for deceleration rotation transmission from the crankshaft to the camshaft of the internal combustion engine which concerns on one Embodiment of this invention, and the chain tensioner for the tension adjustment. It is a front sectional view of a chain tensioner in a chain tension control device of an internal-combustion engine concerning one embodiment of the present invention. It is a flowchart which shows the schematic procedure of the stop control of the internal combustion engine in the chain tension control apparatus of the internal combustion engine which concerns on one Embodiment of this invention. 5 is a graph showing a cam torque variation tendency with respect to rotation of a crankshaft in an internal combustion engine according to an embodiment of the present invention, where the vertical axis represents cam torque and the horizontal axis represents crank angle. 5 is a graph showing measurement results of fluctuation values of chain tension and cam torque with respect to rotation of a crankshaft in an internal combustion engine according to an embodiment of the present invention, where the vertical axis represents chain tension and cam torque, and the horizontal axis represents crank angle. 4 is a graph showing a relationship between a piston position and a chain tension reduction period in an internal combustion engine according to an embodiment of the present invention, where the vertical axis represents the piston position and the horizontal axis represents the crank angle. 4 is a graph showing the relationship between changes in the valve lift and the torque of the valve camshaft with respect to the rotation of the valve camshaft of the internal combustion engine according to the embodiment of the present invention, where the vertical axis represents the valve lift and cam torque, and the horizontal axis represents the camshaft rotation angle. .

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(One embodiment)
FIGS. 1 to 3 show the configuration of a chain tension control device for an internal combustion engine according to an embodiment of the present invention. FIGS. 4 to 8 illustrate the operation of the internal combustion engine and the tension control device. It is.

  First, the configuration will be described.

  The chain tension control device for an internal combustion engine of the present embodiment is applied to a multi-cylinder internal combustion engine, and is installed in the engine 10 as shown in FIGS.

  The engine 10 is a spark ignition type in-line four-cylinder engine. The engine 10 includes an engine main body 12 that forms a plurality of cylinders 11, a plurality of pistons 14 that are slidably provided in the plurality of cylinders 11 and that form a combustion chamber 13, and the plurality of pistons 14 are connecting rods. 15 and a crankshaft 16 connected through 15.

  Further, the ignition timing of the engine 10 is controlled so that a spark is emitted to the compressed mixed gas in the combustion chamber 13 and the intake valve 17 and the exhaust valve 18 that are disposed on the upper side of the combustion chamber 13 so as to be able to open and close. An ignition plug 19 and a valve mechanism 20 that opens and closes the intake valve 17 and the exhaust valve 18 according to the stroke position of the piston 14 as the crankshaft 16 rotates are provided.

  The valve mechanism 20 is, for example, an intake air coupled to the crankshaft 16 via a chain 61 that is an endless transmission element so as to rotate at a rotational speed half that of the crankshaft 16 [rpm]. The intake valve 17 and the exhaust valve 18 are opened and closed in response to changes in lift associated with the rotation of the cam shaft 21 on the exhaust side and the cam shaft 22 on the exhaust side, and the cam shaft 21 on the intake side and the cam shaft 22 on the exhaust side. It includes a rocker arm (not shown) that drives in the direction, a valve spring, and the like.

  An injector 23 (fuel injection valve) is attached to the intake port portion 11 a of each cylinder 11, and the plurality of injectors 23 corresponding to the plurality of cylinders 11 are respectively connected to delivery pipes 24. Fuel in a fuel tank (not shown) is supplied to the delivery pipe 24 by a fuel pump via a pressure regulator.

  The intake pipe 26 connected to the intake port portion 11a of each cylinder 11 is provided with a surge tank 26a having a predetermined volume for suppressing intake pulsation and intake interference, and intake air in the vicinity of an air cleaner (not shown) on the upstream side. An air flow meter 27 for detecting the amount, and a throttle valve 29 located between the air flow meter 27 and the surge tank 26a are mounted.

  An exhaust pipe 31 connected to the exhaust port portion 11b of each cylinder 11 includes an exhaust purification catalyst device 32 made of a three-way catalyst, and an exhaust passage in the vicinity of the catalyst device 32, for example, upstream of the catalyst device 32. A limit current type A / F sensor 33 (air-fuel ratio sensor) for detecting the exhaust air-fuel ratio is mounted.

  Further, the engine 10 includes a crank angle sensor 41 that detects a crank angle that is a rotation angle from the reference crank angle position of the crankshaft 16, and reference cam angle positions of the intake side camshaft 21 and the exhaust side camshaft 22. The intake side and exhaust side cam angle sensors 42, 43 for detecting the cam angle, which is the rotation angle from, are mounted.

  The crank angle sensor 41 is constituted by a crank angle detection rotor 41a provided so as to be rotatable integrally with the crankshaft 16, and an electromagnetic pickup 41b disposed in the vicinity thereof.

  On the outer periphery of the crank angle detecting rotor 41a, a plurality of teeth (no symbol) are formed at a predetermined angular pitch (for example, every 10 ° CA (crank angle)), and a plurality of teeth (at a specific location on the outer periphery) For example, a missing tooth portion of 30 ° CA is provided. The electromagnetic pickup 41b is adapted to generate a voltage pulse every time the outer peripheral teeth of the crank angle detecting rotor 41a pass the vicinity. By monitoring the generation interval and the number of the generated voltage pulses, The rotational phase (rotational angle position) of the crankshaft 16 can be detected.

  The intake side and exhaust side cam angle sensors 42, 43 are constituted by cam angle detecting rotors 42a, 43a and electromagnetic pickups 42b, 43b. The cam angle detecting rotor 42a is attached to the intake side cam shaft 21 so as to be integrally rotatable, and the cam angle detecting rotor 43a is attached to the exhaust side cam shaft 22 so as to be integrally rotatable. Each of the cam angle detection rotors 42a and 43a has a different tooth shape, for example, depending on an angle section around the rotation axis, and is missing in one section.

  In addition, each electromagnetic pickup 42b, 43b changes its voltage positively or negatively by electromagnetic induction every time the outer teeth of the corresponding cam angle detecting rotor 42a or 43a pass in the vicinity (the proximity state of the teeth is switched). A cam angle detection signal is generated.

  Then, the ECU 50 generates a cam signal that is switched on and off in accordance with the positive / negative change of the detection signal of the cam angle sensor 42, and when the first missing tooth signal input from the crank angle sensor 41 is confirmed. If the cam signal is on, the first cylinder is at the compression top dead center when the TDC signal is output. If the cam signal is off at that time, the first cylinder is on the exhaust when the TDC signal is output. The cylinder can be identified as being at the dead point. Note that such cylinder discrimination processing itself is the same as that described in, for example, JP-A-2004-239180.

  The engine 10 also includes an ignition drive circuit 46 that drives the plurality of spark plugs 19 corresponding to the plurality of cylinders 11, and an injection drive circuit 47 that opens the plurality of injectors 23 that correspond to the plurality of cylinders 11. Are connected by wiring, and the fuel pump for supplying fuel to the injector 23 is connected by piping. An alternator 48 as a generator is connected to the crankshaft 16 via an endless transmission belt 49.

  Here, the ignition drive circuit 46 arranges the plurality of spark plugs 19 in a predetermined order (for example, the first cylinder, the third cylinder, etc.) in accordance with a command ignition timing control signal from an ECU (electronic control unit) 50 that electronically controls the engine 10. It is possible to perform ignition driving in the order of cylinder, fourth cylinder, and second cylinder).

  The injection driving circuit 47 can sequentially drive the plurality of injectors 23 to open with a degree of opening (duty ratio) corresponding to the command injection time in accordance with an injection control signal (command injection time) from the ECU 50. ing.

  The alternator 48 is connected to a battery (not shown) and is also connected to various electric loads mounted on the vehicle on which the engine 10 is mounted. When the amount of power generation is larger than the load amount of the various electric loads, the alternator 48 charges the battery. When the power generation amount is smaller than the load amount of various electric loads, the battery has a function of discharging.

  The alternator 48 is equipped with a voltage regulator 48r (voltage regulator). The voltage regulator 48r controls the field current of the alternator 48 in accordance with the output voltage of the alternator 48 and the battery terminal voltage, so that the alternator 48 can supply electric power according to the load amount of various electric loads, and is necessary for the battery. It has a function to execute a proper charge. The voltage regulator 48r can variably set the voltage adjustment level in accordance with the generated voltage control signal from the ECU 50.

  In addition to sensor information from the air flow meter 27, the air-fuel ratio sensor 33, the crank angle sensor 41, and the cam angle sensors 42, 43, the ECU 50 includes various sensor information such as a water temperature sensor, an accelerator opening sensor, a vehicle speed sensor, and a brake switch (not shown). Based on this, the engine 10 is electronically controlled.

  The ECU 50 includes a backup memory such as a nonvolatile memory in addition to a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), although a specific hardware configuration is not illustrated. Furthermore, it is configured to include an input interface circuit including an A / D converter and the like, an output interface circuit including a driver and a relay switch, and a communication interface with other in-vehicle ECUs.

  Here, the input interface circuit of the ECU 50 includes a waveform shaping circuit that takes in the detection signals of the crank angle sensor 41 and the cam angle sensors 42 and 43 and shapes their signal waveforms. The output interface circuit of the ECU 50 includes or is connected to a driver circuit for actuators, etc., and is connected to an injection drive circuit 47 for injecting and driving the injector 23 and an ignition drive circuit 46 for driving and igniting the ignition plug 19. ing.

  The ECU 50 executes, for example, so-called multitask processing in accordance with a control program stored in a ROM or a backup memory (hereinafter referred to as a ROM or the like). The ECU 50 determines the engine speed NE of the engine 10, the charging efficiency KL (the amount of air sucked into each cylinder 11 / the amount of air that can be sucked into each cylinder 11), the ignition timing, the air-fuel ratio A / F, and the like. On the premise of the mutual relationship, for example, it has a function of controlling the throttle opening, ignition timing, fuel injection time, etc. of the engine 10 so as to realize the target torque and the target rotational speed. The ECU 50 can also exhibit the aforementioned crank angle detection function and cylinder discrimination function in accordance with a control program stored in a ROM or the like.

  In the present embodiment, the ECU 50 further exhibits a function of controlling the rotation stop angle position of the crankshaft 16 within a specific stop angle region when the operation of the engine 10 is stopped. A stop angle control unit 51 (stop angle control mechanism) including a program, a memory area, setting information and the like for exhibiting the function is attached.

  In this embodiment, the stop angle control unit 51 is described as controlling the rotation stop angle position of the crankshaft 16 within a specific stop angle region, but the crankshaft 16 and the exhaust-side camshaft 22 (tensioner) are described. The rotation stop angle position of either one or both of them may be controlled within one or both specific stop angle regions.

  The specific stop angle region here refers to the chain tensioner from the chain 61 when the tension acting on the chain 61 varies according to the rotational angle position of the crankshaft 16 and the intake and exhaust camshafts 21 and 22. The load applied to 62 (load Fc shown in FIG. 3) corresponds to the crank angle region on the low load side within the fluctuation range, and particularly the load applied to the chain tensioner 62 when the crankshaft 16 stops rotating is within the fluctuation range. The stop angle region that can fall within a certain range from the minimum load.

  Further, the moving part of the chain 61 on the chain tensioner 62 side means that the tension is adjusted by the chain tensioner 62 in a section where the chain sprocket 16sp on the crankshaft 16 moves to the chain sprocket 22sp on the camshaft 22 on the exhaust side. This is the part.

  By the way, the chain 61 is guided by a slipper 65 with a moving part 61z1 on the loose side of the chain tensioner 62, and a moving part 61z2 between the intake-side and exhaust-side camshafts 21 and 22, and an intake-side cam. The tension side moving portion 61z3 from the shaft 22 to the crankshaft 16 is guided by the respective fixed guide units 66 and 67.

  The stop angle control unit 51 variably controls the load torque acting on the crankshaft 16 from the auxiliary side connected to the engine 10. For example, according to the power generation output (field current, power generation voltage) of the alternator 48. Thus, the rotational load torque of the alternator 48 that changes is variably controlled.

  Specifically, the stop angle control unit 51 variably controls the field current flowing in the field coil of the alternator 48 when the operation of the engine 10 is stopped, so that the rotational load torque of the alternator 48 is increased and decreased (decreased). The crankshaft 16 is controlled at a crank angle within a specific stop angle region by controlling in at least one of the (small) directions.

  By the way, the stop angle position of the crankshaft 16 is likely to stop in a region where a combined value of torque acting on the crankshaft 16 (hereinafter referred to as a combined torque) decreases. The combined torque acting on the crankshaft 16 applies pressure in the plurality of cylinders 11 (four in this embodiment) of the engine 10 and the plurality of intake valves 17 and exhaust valves 18 of the valve mechanism 20 in the valve closing direction. It changes according to the reaction force of the plurality of valve springs to be applied and the friction of each sliding part. In general, this combined torque increases in the vicinity of a crank angle range in which any one of the plurality of cylinders 11 is in the latter half of the compression stroke.

  Further, the tension of the moving portion 61z1 on the chain tensioner 62 side of the chain 61 varies with the rotational load torque of the exhaust side camshaft 22 on the chain tensioner 62 side of the intake side and exhaust side camshafts 21 and 22. It becomes small when it is on the high torque side within the range.

  Therefore, the specific stop angle region in which the crankshaft 16 is stopped when the operation of the engine 10 is stopped is an angle region where the rotational load torque of the exhaust-side camshaft 22 is on the high torque side within the fluctuation range, and the crankshaft It is preferable that the combined torque acting on 16 be an angle region on the low torque side of the fluctuation range.

  FIG. 5 shows changes in the rotational load torque (“cam torque” in the figure; hereinafter referred to as “exhaust cam torque”) of the cam shaft 22 on the exhaust side with respect to changes in the crank angle. The exhaust cam torque is a portion surrounded by a dotted-line ellipse in the figure and is on the high torque side within a certain range from the maximum torque.

  FIG. 6 shows a comparison between the change in the exhaust cam torque and the change in the tension of the moving part 61z1 on the tensioner side of the chain 61 and the change in the tension of the moving part 61z3 on the tension side. In contrast to the change in exhaust cam torque indicated by the broken line in FIG. 6, the tension of the moving portion 61z3 (see FIG. 2) on the tight side of the chain 61 indicated by the dotted line in FIG. It shows a similar trend.

  On the other hand, the tension of the moving portion 61z1 on the tensioner side, which is the loose side of the chain 61, fluctuates with a tendency to have a phase opposite to the change in the exhaust cam torque, as shown by the solid line in FIG. That is, a specific stop where the exhaust cam torque is on the high torque side and the tension of the moving part 61z3 on the tight side of the chain 61 is on the high tension side, and both the exhaust cam torque and the tension of the moving part 61z3 on the tight side start to decrease. The moving part on the tensioner side in the angle region Za (for example, the crank angle region from the crank angle 40 ° CA before the crank angle corresponding to the maximum valve lift of the exhaust valve 18 to the crank angle corresponding to the maximum valve lift). The tension of 61z1 is the smallest.

  When this specific stop angle region Za is shown in association with the position of the piston 14 of the engine 10, as shown in FIG. 7, the crankshaft is passed past the vicinity of the crank angle range which is the latter stage of the compression stroke in any cylinder. 16 is a section in which the combined torque acting on 16 decreases.

  It should be noted that # 1 to # 4 shown by adding a square frame to the upper part of FIG. 6 indicate the cylinder numbers for the exhaust stroke. FIG. 8 shows the relationship between the valve lift [mm] of the exhaust valve 18 and the cam torque that changes positively and negatively according to the valve lift.

  The stop angle control unit 51 of the ECU 50 is operated when an ignition switch (not shown) is manually operated to the OFF side and an ignition OFF request is generated, or when an ignition OFF request is generated for automatic stop of the engine 10 or the like. The crankshaft 16 is stopped within a specific stop angle region Za by variably controlling the rotational load torque of the alternator 48.

  For this purpose, the stop angle control unit 51 determines the magnitude of the field current of the alternator 48 and its variable control pattern during the period from when the ignition OFF request is generated until the crankshaft 16 stops rotating, through experiments or the like. It is stored in ROM or the like. The magnitude of the field current and its variable control pattern are selected from multiple types according to the coolant temperature when the ignition OFF request is generated, the operating state of the auxiliary machine, the engine speed [rpm], etc. The stop control time may be changed.

  On the other hand, as shown in FIG. 2, the engine 10 adjusts the endless chain 61 that rotates between the crankshaft 16 and the intake and exhaust camshafts 21 and 22 and the tension acting on the chain 61. A chain tensioner 62.

  As shown in FIGS. 2 and 3, the chain tensioner 62 includes a plunger 71 on which an axial load Fc corresponding to the tension acting on the chain 61 is applied, and a sliding hole that holds the plunger 71 slidably with a minute clearance. A tensioner housing 74 having a portion 72 and a compression coil spring 75 (biasing mechanism) assembled in a compressed state between the plunger 71 and the tensioner housing 74 are configured.

  The tensioner housing 74 defines a hydraulic chamber 73 closed by a plunger 71 inside the sliding hole 72, and can generate a hydraulic reaction force that opposes the load Fc inside the hydraulic chamber 73. It is like that. The tensioner housing 74 is formed with a mounting hole 74h for fastening the chain tensioner 62 to the engine body 12 with bolts.

  The compression coil spring 75 is interposed between the plunger 71 and the tensioner housing 74, and is an elastic member that constantly urges the plunger 71 in the reaction force direction (the direction of the arrow Fp in FIG. 3) against the load Fc, that is, hydraulic pressure. The elastic member is energized even when the fluid pressure in the chamber 73 is lowered. The compression coil spring 75 is applied in the reaction force direction while being compressed according to the retraction amount when the plunger 71 is retreated from the predetermined position to the inner back side of the sliding hole portion 72 by the load Fc applied from the chain 61. Increases power.

  The chain tensioner 62 further includes a check valve 77 that opens and closes according to a differential pressure between the hydraulic pressure in the hydraulic chamber 73 and the hydraulic pressure in the oil supply passage 76 that can supply oil to the hydraulic chamber 73. The check valve 77 is switchable between an open state in which the hydraulic chamber 73 is connected to the oil supply passage 76 and a closed state in which the hydraulic chamber 73 is shut off from the oil supply passage 76.

  When the hydraulic pressure in the hydraulic chamber 73 is higher than the hydraulic pressure in the oil supply passage 76, the check valve 77 is closed while applying an urging force in the valve closing direction (arrow Fp direction) corresponding to the differential pressure to the plunger 71. On the other hand, when the hydraulic pressure in the hydraulic chamber 73 is lower than the hydraulic pressure in the oil supply passage 76, the hydraulic chamber 73 is configured to open so as to connect to the oil supply passage 76.

  More specifically, as shown in FIG. 3, the check valve 77 includes a valve seat 77 s provided in the plunger 71 so as to form a part of the oil supply passage 76, and a valve seat 77 s in the hydraulic chamber 73. And a check valve body 77v arranged to be seated. Here, the range of movement of the check valve body 77v with respect to the plunger 71 is limited by the retainer 78 having a plurality of radial communication holes 78h, and a separation distance from the valve seat 77s (a gap when the valve is opened) is defined. It is like that. Further, the valve seat 77s is formed by press-fitting a cylindrical sleeve 71c into the opened inner end 71b side of the substantially bottomed cylindrical plunger main body 71a, so that one end of the sleeve 71c protruding into the hydraulic chamber 73 is inside. It is comprised by the surrounding part.

  The retainer 78 is fitted and fixed to the sleeve 71c, for example, but may have a flange portion pressed against the plunger 71 by the compression coil spring 75, or the inner periphery of the inner end portion 71b of the plunger main body 71a. The wall portion may be fitted and held.

  A low pressure chamber 81 that stores oil while forming a part of an oil supply passage 76 that can be connected to the hydraulic chamber 73 is formed inside the plunger 71, and oil can be supplied to the low pressure chamber 81 from the outside. In addition, at least one radial through hole 82 is formed to allow the low pressure chamber 81 to communicate with the external supply passage 83. During operation of the engine 10, oil supplied from the oil pump in the drawing is supplied from the external supply passage 83 into the hydraulic chamber 73 through the through hole 82 and the low pressure chamber 81.

  The tensioner housing 74 is formed with a communication groove 74 c that faces the opening of the through hole 82 on the outer peripheral surface of the plunger 71. The communication groove 74c is obtained by expanding a portion where the external supply passage 83 opens on the inner peripheral wall surface of the sliding hole portion 72 at least in the axial direction of the plunger 71. 82 is communicated with the external supply passage 83.

  As shown in FIG. 3, when the chain tensioner 62 is installed in an inclined attitude (hereinafter simply referred to as an inclined attitude) that inclines the axis of the plunger 71, the engine 10 is stopped and the supply of the operation from the external supply passage 83 is performed. When the stopped state continues, the oil level L of the oil can be formed inside the sliding hole 72 of the tensioner housing 74.

  When the chain tensioner 62 is installed in an inclined posture, the communication groove 74c of the tensioner housing 74 is disposed so as to be positioned on the lower side in the vertical direction from the oil level L, as shown by a solid line in FIG. It has a belt-like groove shape. However, the communication groove 74 c may be an annular groove extending over the entire inner periphery of the sliding hole portion 72 so as to include a portion indicated by a virtual line in FIG. 3.

  Although the compression coil spring 75 is disposed inside the pressure chamber 73, the compression coil spring 75 may be interposed between the plunger 71 and the tensioner housing 74 so as to constantly apply a biasing force in the reaction direction to the plunger 71. Good. Further, the compression coil spring 75 may be an elastic member other than a spring, or may be constituted by an arbitrary urging mechanism configured to constantly urge the plunger 71 in a reaction force direction against the load Fc.

  Next, the operation will be described.

  In the chain tension control device for an internal combustion engine of the present embodiment configured as described above, the hydraulic chamber 73 for generating a hydraulic reaction force in the chain tensioner 62 is located inside the tensioner housing 74, that is, a plunger sliding hole. The check valve 77 is positioned on the plunger 71 side with respect to the hydraulic chamber 73. Therefore, it is difficult for air to enter the hydraulic chamber 73.

  In the present embodiment, when an ignition OFF request is generated to stop the engine 10, stop control as shown in FIG. 4 is executed.

  That is, the rotation stop angle of the crankshaft 16 is controlled within a specific stop angle region Za so that the load Fc applied from the chain 61 to the chain tensioner 62 when the operation of the engine 10 is stopped is on the low load side (step S11).

  Therefore, when the rotation of the crankshaft 16 is completely stopped, the stop angle position is located within the specific stop angle region Za, and the rotational load torque of the exhaust-side camshaft 22 is on the high torque side within the fluctuation range. In addition, the resultant torque acting on the crankshaft 16 is in the low torque side of the fluctuation range. As a result, the relaxed state after the stop is determined in a state where the tension of the moving portion 61z1 on the tensioner side of the chain 61 enters the low load side within the constant fluctuation range from the minimum value within the fluctuation range (step S12).

  As a result, the load Fc acting on the plunger 71 from the chain 61 is determined at a low load, and it is effectively suppressed that the oil in the hydraulic chamber 73 is excessively pressurized and leaks outside after the engine 10 is stopped. (Step S13).

  Therefore, it is possible to reduce oil leakage countermeasure parts such as a conventional ratchet mechanism and resin bar, and the cost of the chain tensioner 62 can be reduced. In addition, as in this embodiment, the mounting angle of the chain tensioner 62 (inclination of the axis of the plunger with respect to the vertical direction) is large, and even when the engine 10 is restarted after being left for a long time after the engine 10 is stopped. Occurrence of abnormal noise and tooth skipping at the time of starting is accurately prevented.

  In the present embodiment, the rotation stop angle of the crankshaft 16 can be accurately controlled within the specific stop angle region Za based on the detection information of the existing crank angle sensor 41.

  Moreover, since the stop angle control unit 51 variably controls the load torque acting on the crankshaft 16 from the alternator 48 side connected to the engine 10, the load Fc applied from the chain 61 to the chain tensioner 62 can be easily and accurately controlled. . In addition, an existing stop control mechanism that controls the rotation stop angle position of the crankshaft 16 within a predetermined range by adjusting the load torque of the auxiliary machine in order to improve restartability in an idling stop vehicle or the like (for example, see Japanese Patent Application Laid-Open 2012-136980, JP-A-2008-215230, etc.) can also be used.

  Further, in the present embodiment, the check valve 77 has a valve seat 77 s and a check valve body 77 v, and a part of the oil supply passage 76 is formed in the plunger 71. Even if air is mixed, it is possible to easily secure a route for bleeding air from the oil to the outside of the sliding hole 72 without passing through the high pressure hydraulic chamber 73. Further, in the arrangement form of the present embodiment in which the outer end portion of the plunger 71 to which the load Fc is applied from the chain 61 is located vertically above the inner end portion 71b receiving the hydraulic reaction force, the hydraulic chamber 73 serving as the high pressure chamber is provided in the arrangement form of the present embodiment. Is hard to get air.

  In addition, in this embodiment, a low pressure chamber 81 that stores oil while forming a part of the oil supply passage 76 is formed inside the plunger 71, and when the load Fc from the chain 61 is applied to the plunger 71, The hydraulic chamber 73 and the low pressure chamber 81 are shut off by a check valve. Therefore, even if air enters the low-pressure chamber 81 when the load Fc is not applied to the plunger 71, the air moves to the uppermost portion in the low-pressure chamber 81, and the check is caused by the action of the compression coil spring 75. Under the condition that the valve 77 is opened, oil is supplied without mixing air into the hydraulic chamber 73. On the other hand, when the load Fc is applied to the plunger 71 and the hydraulic pressure in the hydraulic chamber 73 starts to rise, the check valve 77 is closed, the hydraulic chamber 73 is shut off from the oil supply passage 76 side, and the hydraulic pressure in the hydraulic chamber 73 is reduced. Quickly reach high pressure according to chain tension.

  In the present embodiment, the compression coil spring 75 is interposed between the plunger 71 and the tensioner housing 74, and constantly urges the plunger 71 in the direction Fp that opposes the load Fc. Can be configured. Moreover, since the plunger 71 can be incorporated into the tensioner housing 74 in a state where the compression coil spring 75 is held in advance by the plunger 71, assembly can be facilitated.

  As described above, in the present embodiment, the hydraulic chamber 73 that generates the hydraulic reaction force is positioned on the inner back side of the tensioner housing 74 so that oil can be supplied from the plunger 71 side, and when the operation of the engine 10 is stopped. The load Fc applied from the chain 61 to the chain tensioner 62 is controlled to the low load side. Therefore, it is possible to effectively suppress the oil in the hydraulic chamber 73 from leaking outside or the air entering the hydraulic chamber 73 due to the load Fc applied to the plunger 71. As a result, it is possible to reduce the oil leakage countermeasure parts such as the ratchet mechanism to reduce the cost of the chain tensioner 62, and to accurately prevent the generation of noise and tooth skipping at the start of the engine 10 equipped with the chain tensioner 62. can do.

  In the above-described embodiment, the engine 10 is an in-line four cylinder, but another type of internal combustion engine may be used. In the present embodiment, the stop angle position of the crankshaft 16 is controlled within the specific stop region Za, but the stop angle position of the camshaft located on the tensioner side is controlled within the specific stop angle region corresponding thereto. Alternatively, the stop angle positions of both the crankshaft 16 and the camshaft located on the tensioner side may be controlled within a specific stop angle region.

  Further, the stop angle position of the crankshaft 16 is controlled within the specific stop area Za based on the detection information of the crank angle sensor 41, but the engine 10 is controlled based on the rotational position of the camshaft and other sensor information. It is also conceivable to control the rotational load at the time of stopping.

  As described above, the chain tension control device for an internal combustion engine according to the present invention can effectively suppress the leakage of oil in the hydraulic chamber or the entry of air into the hydraulic chamber due to the load applied to the plunger. As a result, it is possible to reduce the number of oil leakage countermeasure parts and reduce the cost of the chain tensioner, and to accurately prevent the occurrence of abnormal noise and tooth skipping at the start of the internal combustion engine equipped with the chain tensioner. An engine chain tension control device can be provided. Therefore, the present invention is useful for all chain tension control devices for internal combustion engines that control the tension acting on the chain between the crankshaft and the camshaft of the internal combustion engine to which the chain tensioner is attached.

DESCRIPTION OF SYMBOLS 10 ... Engine (internal combustion engine), 11 ... Cylinder, 12 ... Engine main body, 13 ... Combustion chamber, 14 ... Piston, 16 ... Crankshaft, 17 ... Intake valve, 18 ... Exhaust valve, 19 ... Spark plug, 20 ... Valve Mechanism 21 ... Intake side camshaft 22 ... Exhaust side camshaft (tensioner side camshaft) 23 ... Injector (fuel injection valve) 24 ... Delivery pipe 26 ... Intake pipe 29 ... Throttle valve 31 Exhaust pipe, 41 ... Crank angle sensor, 42, 43 ... Cam angle sensor, 46 ... Ignition drive circuit, 47 ... Injection drive circuit, 48 ... Alternator (auxiliary), 48r ... Voltage regulator (voltage regulator), 49 ... Endless transmission belt, 50 ... ECU (electronic control unit), 51 ... Stop angle control section (stop angle control mechanism), 61 ... Chain (endless rotation transmission element), 61z1 ... Tensioner side Moving part (moving part on the loose side, part of the chain), 61z3 ... moving part on the tension side, 62 ... chain tensioner, 71 ... plunger, 71a ... plunger body, 71b ... inner end, 71c ... sleeve, 72 ... sliding Moving hole portion 73 ... Hydraulic chamber (high pressure chamber), 74 ... Tensioner housing, 74c ... Communication groove, 76 ... Oil supply passage, 77 ... Check valve, 77s ... Valve seat, 77v ... Check valve body, 78 ... Retainer 78h: Radial communication hole, 81: Low pressure chamber, 82: Through hole, 83: External supply passage

Claims (6)

A chain tension control device for an internal combustion engine, comprising: an endless chain that rotates between a crankshaft and a camshaft; and a chain tensioner that adjusts a tension acting on the chain.
The chain tensioner is
A plunger on which a load corresponding to the tension is applied;
A tensioner housing that slidably holds the plunger and that defines a hydraulic chamber that generates a hydraulic reaction force that opposes the load;
An urging mechanism for applying an urging force in a direction against the load to the plunger;
The hydraulic chamber is opened and closed according to a differential pressure between the hydraulic pressure in the hydraulic chamber and the hydraulic pressure in an oil supply passage capable of supplying oil to the hydraulic chamber, and the hydraulic chamber is connected to the oil supply passage. And a check valve that switches to a closed valve state that shuts off from the oil supply passage,
When the hydraulic pressure in the hydraulic chamber is higher than the hydraulic pressure in the oil supply passage, the check valve closes while applying a biasing force in the valve closing direction corresponding to the differential pressure to the plunger. When the hydraulic pressure is lower than the hydraulic pressure in the oil supply passage, the valve is opened and the hydraulic chamber is connected to the oil supply passage.
The internal combustion engine controls a rotation stop angle position of either the crankshaft or the camshaft within a specific stop angle region where the load that changes according to the rotation stop angle position is on a low load side. A chain tension control device for an internal combustion engine, comprising a stop angle control mechanism.   The chain tension control device for an internal combustion engine according to claim 1, wherein the stop angle control mechanism controls a rotation stop angle position of the crankshaft of the internal combustion engine within the specific stop angle region.   The chain tension control device for an internal combustion engine according to claim 2, wherein the stop angle control mechanism variably controls a load torque acting on the crankshaft from an auxiliary machine side connected to the internal combustion engine.   The check valve is disposed so as to be seated on the valve seat in the hydraulic chamber and a valve seat provided on the plunger so as to form a part of the oil replenishment passage, and is spaced from the valve seat. The chain tension control of the internal combustion engine according to any one of claims 1 to 3, further comprising a check valve body held by the plunger so as to be restricted. apparatus.   A low pressure chamber for storing the oil while forming a part of the oil supply passage is formed inside the plunger, and the hydraulic chamber and the low pressure chamber are applied when a load corresponding to the tension is applied to the plunger. The chain tension control device for an internal combustion engine according to claim 4, wherein the check valve is blocked by the check valve.   The said urging mechanism is comprised between the said plunger and the said tensioner housing, and is comprised by the elastic member which always urges | biases the said plunger in the direction which opposes the said load. The chain tension control device for an internal combustion engine according to any one of claims 5 to 9.

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