JP4518055B2 - Method and apparatus for measuring valve lift amount of internal combustion engine - Google Patents

Description

  The present invention relates to a valve lift amount measuring method and a measuring device for an internal combustion engine, and more particularly, to a valve lift amount of a variable valve mechanism capable of controlling a valve operation timing and a lift amount in accordance with an operating state of the engine. It is related with the method and apparatus which measure by.

  As a variable valve mechanism for an engine, as described in Patent Document 1, a drive cam provided on a drive shaft that rotates in conjunction with a crankshaft, and an intake or exhaust for the engine supported by the drive shaft so as to be swingable. A swing cam for lifting a valve for use and a control shaft different from the drive shaft are provided so as to be swingable. One end is connected to the drive cam via the first link member, and the other end is the second link. And a rocker arm connected to the swing cam via a member, and the rotational position of the control shaft is controlled according to the engine operating state, so that the valve lift amount is variably controlled by changing the swing fulcrum of the rocker arm. Such a variable valve mechanism has been proposed.

Further, as a technique for measuring the valve lift amount of an engine, for example, as described in Patent Document 2, a rod is brought into contact with a retainer at the end of a valve stem, and the displacement of the rod interlocking with the movement of the valve is non-contact type. Some are detected by a displacement sensor.
JP 2002-256832 A JP-A-3-156116

  Since the valve lift amount of the engine is an important factor related to the engine performance, in particular, in the variable valve mechanism as described in Patent Document 1, the variable valve mechanism is attached to the cylinder head with a linear scale or the like. It is possible to measure the valve lift. On the other hand, in a so-called bare engine in which a cylinder head having a variable valve mechanism is assembled to a cylinder block, the amount of valve lift may change due to the influence of tightening deformation of the cylinder head with respect to the cylinder block. Even in the state of a bare engine, it is necessary to measure the valve lift and guarantee the accuracy.

  The bare engine refers to a state in which the intake system, exhaust system, and electrical components are removed from the engine assembly including the cylinder head and the cylinder block as main elements. For example, the crankshaft can be rotationally driven by an electric motor or the like. In this case, the piston and valve move normally, and the air is sucked and exhausted.

  However, in the variable valve mechanism described in Patent Document 1, a cam mechanism is complicatedly arranged above the valve due to the particularity of the mechanism, and in particular, a valve lifter that is extrapolated to the stem end of the valve stem. Since the swing cam is in pressure contact with the crown portion of the lens, it is not possible to secure a portion to which a contact of a measuring instrument such as a linear scale is applied, making it difficult to guarantee the actual amount of valve lift.

  Even if the valve lift can be measured with a measuring instrument such as a linear scale using the crown of the valve lifter as the non-measuring surface, the variable valve mechanism is characterized by the displacement of the swing cam. The valve lifter tilts (the valve lifter shaft center is tilted with respect to the valve stem axis), and the valve lift amount cannot be adjusted accurately due to this unstable posture or behavior. There is a problem that it cannot be measured.

  The present invention has been made paying attention to such a problem, and in particular, it is possible to measure the valve lift amount with high accuracy for a variable valve mechanism of an internal combustion engine including a variable valve mechanism of a special form as described above. The present invention provides a method and an apparatus that can be used in the future.

  The invention according to claim 1 is a state in which the relative positional relationship between the valve stem and the valve lifter is corrected with a magnetic adsorption force by magnetizing the valve on the premise that the valve lift amount of the internal combustion engine is measured. While the camshaft is driven to rotate, the crown portion of the valve lifter is used as a surface to be measured, and the displacement of the crown portion is measured as a valve lift amount by a non-contact displacement meter.

  More specifically, as described in claim 2, a valve lifter is adsorbed to the stem end of the valve stem so as to correct the relative positional relationship between the valve stem and the valve lifter. The posture or behavior shall be corrected so that the fall of the mind is minimized.

  In addition, as described in claim 3, the valve stem of the valve is magnetized by the valve magnetizing means through the intake port or the exhaust port, and an electromagnetic coil is used as the valve magnetizing means as described in claim 4. The yoke of the electromagnetic coil is inserted from the intake port or the exhaust port, and the valve stem is magnetized by bringing the yoke close to the valve stem.

  Further, as the non-contact type displacement meter, for example, a laser displacement meter which is an optical displacement meter as described in claim 5 is used.

  A sixth aspect of the present invention is the valve lift amount measuring device for an internal combustion engine used for the valve lift amount measurement according to the first aspect, wherein the technique according to the first aspect is used. Rotational drive means for rotationally driving, valve magnetizing means for correcting the relative positional relationship between the valve stem and the valve lifter by magnetizing the valve with a magnetic attraction force, and the crown part of the valve lifter as a measured surface. And a non-contact displacement meter that measures the displacement as a valve lift amount.

  As a result of various experiments conducted by the inventor, the valve lifter follows the movement of the swing cam by correcting the relative positional relationship between the valve stem and the valve lifter with a magnetic adsorption force by magnetizing the valve. Even when lifted together, it has been found that the posture or behavior of the valve lifter is not stable, such as the axis of the valve lifter tilting with respect to the valve stem, and at least the posture or behavior of the valve lifter is stabilized.

  At the same time, when measuring the displacement of the crown of the valve lifter using a non-contact displacement meter such as a laser displacement meter, the occlusion accuracy is assured if a non-measurement part of about 3 mm is secured in the crown. It has been found that there is no problem and that a non-measurement portion of the same size can be secured in the crown portion of the valve lifter where the cam is pressed.

  Therefore, in at least the first and sixth aspects of the invention, by magnetizing the valve, the camshaft is rotationally driven in a state where the relative positional relationship between the valve stem and the valve lifter is corrected with a magnetic adsorption force, so that the valve is While lifting with the lifter, if the crown of the valve lifter is the measured surface and the displacement of the crown is measured with a non-contact displacement meter, the displacement can be measured and grasped quantitatively as the valve lift. Is possible.

  According to the first and sixth aspects of the invention, not only the special variable valve mechanism as described above, but also any internal combustion engine can be measured with high accuracy and speed in the so-called bare engine state. can do. In particular, by correcting the relative positional relationship between the valve stem and the valve lifter with a magnetic attraction force, the posture or behavior of the valve lifter is stabilized, and the measurement accuracy of the valve lift is dramatically improved.

  FIG. 1 and the following drawings show a more specific embodiment of the present invention. Here, for example, a valve lift amount (hereinafter simply referred to as lift) of a variable valve mechanism applied to an intake system of a V-type 6-cylinder engine. An example in the case of measuring a quantity) is shown.

  1 to 4, as an example of a variable valve mechanism provided on the cylinder head 1, both the lift amount and the operating angle of the intake valve 2 are continuously controlled while opening and closing the two intake valves 2 per cylinder. The structure of the variable lift / operating angle (valve event) variable mechanism 3 that can be variably controlled is shown. The lift / operating angle variable mechanism 3 has been previously proposed by the present applicant and the like as Japanese Patent Application Laid-Open No. 2002-256832.

  The variable lift / operating angle mechanism 3 includes a drive shaft 4 as a camshaft that rotates in conjunction with a crankshaft (not shown), and is fitted to and supported by the drive shaft 4 so as to be swingable, and lifts the intake valve 2. The swing cam 5 is linked with a plurality of links 10 and 11 in addition to a rocker arm 9 described later. More specifically, the lift / operating angle variable mechanism 3 includes a circular eccentric cam 6 that is provided eccentric to the drive shaft 4 and functions as a drive cam, a control shaft 7 that is provided in parallel to the drive shaft 4, and this control. A circular eccentric cam 8 that is eccentrically provided on the shaft 7, a rocker arm 9 that is swingably fitted to the eccentric cam 8, and the eccentric cam 6 on the drive shaft 4 side and one end of the rocker arm 9 are connected. It has a ring-shaped first link 10 as a first link member, and a second link 11 as a second link member connecting the other end of the rocker arm 9 and the tip of the swing cam 5. Yes.

  The drive shaft 4 is linked to a crankshaft via a transmission mechanism such as a chain or pulley (not shown) and is driven to rotate in conjunction with the crankshaft, while the control shaft 7 is a rotary type (not shown) such as a servo motor. The rotational position is arbitrarily variably controlled by the actuator.

  The first link 10 is rotatably fitted to the outer periphery of the eccentric cam 6 on the drive shaft 4 side, while one end of the rocker arm 9 and the tip of the first link 10 are rotatably connected by a first connecting pin 12. Has been. The other end of the rocker arm 9 and one end of the second link 12 are rotatably connected by a second connecting pin 13. Further, the other end of the second link 11 and the tip of the swing cam 5 are rotatably connected by a third connecting pin 14. Here, as is apparent from FIG. 4, the swing cam 5 is formed by coaxially forming two independent cam bodies 5a and 5b for each intake valve 2, and one cam body 5a has The second link 11 is connected via a third connecting pin 14.

  As shown in FIGS. 1 and 2, the drive shaft 4 and the control shaft 7 are rotatably supported on the upper portion of the cylinder head 1. The cylinder head 1 has a so-called ladder frame structure ladder cam bracket 1b in which a plurality of bearing caps are formed integrally with a frame-like frame on the upper surface of a head lower 1a that functions as a head body. The functioning ladder cam bracket 1 b is fastened and fixed to the head lower 1 a by a plurality of mounting bolts 15. The drive shaft 4 and the control shaft 7 extend in the cylinder row direction while maintaining a parallel state, and the drive shaft 4 is supported by bearings so as to be sandwiched between the head lower 1a and the ladder cam bracket 1b. 7 is mounted on the upper surface of the ladder cam bracket 1b and supported by a bearing cap 16 that is bolted and fixed to the ladder cam bracket 1b.

  As described above, the drive shaft 4 and the control shaft 7 extending in the cylinder row direction are shared by a plurality of cylinders constituting the cylinder row, whereas the components of the lift / operating angle variable mechanism 3 are used. The rocking cam 5, the rocker arm 9, the first link 10, the second link 11 and the like are provided independently for each cylinder constituting the cylinder row.

  In such a lift / operating angle variable mechanism 3, when the drive shaft 4 rotates in conjunction with the crankshaft, the rocker arm 9 swings through the eccentric cam 6 and the first link 10, and the rocker arm 9 swings. The motion is transmitted to the swing cam 5 via the second link 11, and the swing cam 5 swings. As the swing cam 5 swings, the valve lifter 17 provided above the intake valve 2 comes into contact with and presses the valve lifter 17 so that the intake valve 2 reacts with the valve spring 18 (see FIG. 2). In contrast, the opening / closing operation, that is, the lift operation is performed.

  On the other hand, when the rotational position of the control shaft 7 is changed by the operation of a rotary actuator (not shown), the center position of the eccentric cam 8 which is the rocking fulcrum of the rocker arm 9 changes. As a result, the swing range of the swing cam 5 changes, and the lift phase (maximum) of the intake valve 2 remains constant while the central phase of the operating angle of the intake valve 2 with respect to the crank angle (rotational position of the crankshaft) remains substantially constant. Both the lift amount and the operating angle change continuously and steplessly. The control state of the lift / operating angle variable mechanism 3 is detected by, for example, a control axis sensor (lift sensor) that is an angle sensor that responds to the rotational position of the control shaft 7.

  According to the lift / operating angle variable mechanism 3 as described above, for example, by using a minimal lift region where the lift amount is 1 mm or less, the intake air amount can be widely adjusted without depending on the throttle valve. Loss can be greatly reduced or eliminated. However, in such a minimal lift region, a slight lift amount variation between cylinders appears as a relatively large intake air amount variation, so that the lift amount falls within a predetermined control limit (within dimensional tolerance). It is important to make adjustments with high accuracy and to minimize the variation in lift amount between cylinders.

  In the present embodiment, the lift amount is adjusted by adjusting the position of the second connecting pin 13 that connects the rocker arm 9 and the second link 11 constituting the lift / operating angle variable mechanism 3. Adjustment is possible.

  5 to 7 show a pin connecting portion between the rocker arm 9 and the second link 11. The rocker arm 9 has a deformed arm shape having an annular portion 19 that is rotatably fitted to the eccentric cam 8 on the control shaft 7 side, and has a first portion serving as a coupling portion with the first link 10 at one end. In addition to one connecting pin 12 projecting integrally, an arm end 20 that functions as a connecting portion with the second link 11 is integrally formed at the other end. The arm end 20 is formed with an elongated hole insertion hole 21 into which the second connecting pin 13 is inserted.

  The first connecting pin 12 and the arm end 20 are offset from each other in the axial direction of the annular portion 19. In addition, since the short diameter of the pin insertion hole 21 formed in the arm end 20 is substantially matched with the longitudinal direction of the rocker arm 9 itself, the pin insertion hole 21 can be moved in the long diameter direction of the second connection. The pin 13 will be received.

  In the arm end 20 into which the second connecting pin 13 is inserted, an adjustment bolt 22 that functions as an adjustment screw and a lock bolt 23 that functions as a lock screw are inserted into a long hole pin. The holes 21 are opposed to each other so as to be positioned on the same axis with the hole 21 therebetween. In other words, the arm end 20 is formed with female screws 24 and 25 that open into the pin insertion hole 21, the adjustment screw 22 with a hexagonal hole 26 is provided on one screw 24, and the other female screw 25 is provided on the other female screw 25. Lock bolts 23 each having a hexagonal head 27 are screwed together.

  Here, since the adjusting bolt 22 is to rotate the hexagonal wrench type bit 28 shown in FIG. 3 by inserting and fitting it into the hexagonal hole 26, the bit 28 is inserted from the direction of the lock bolt 23. As possible, the lock bolt 23 has a through hole 29 and is hollow. On the other hand, the second connecting pin 13 to be inserted into the pin insertion hole 21 is formed with a two-sided width portion 30 as shown in FIG. Similar to the lock bolt 3, a through hole 31 is formed.

  As apparent from FIG. 5, the bifurcated side piece 11a at one end of the second link 11 is formed with a pin hole 32 that can be fitted to the second connecting pin 13, so that the bifurcated shape. After the arm end 20 is sandwiched between the side piece portions 11a and 11a, the pin insertion hole 21 and the pin hole 32 are matched, and the second connecting pin 13 is inserted into the pin insertion hole 21 and the pin hole 32. Is inserted. Further, the adjustment bolt 22 and the lock bolt 23 are tightened from above and below the second connecting pin 13 inserted into the pin insertion hole 21 and seated on the two-surface width portion 30, so that Two connecting pins 13 are fixed by pressing.

  In addition, the end face of the second connecting pin 13 is formed with a long hole-like depression 33 having a long diameter in the same direction as the pin insertion hole 21. By matching the long diameters of both the long holes, the second It is considered that the two-surface width portion 30 of the connecting pin 13 can be matched with the major axis direction. Therefore, in this state, the through hole 29 of the lock bolt 23 and the through hole 31 of the second connecting pin 13 as well as the hexagonal hole 26 of the adjusting bolt 22 communicate with each other on the same axis.

  As described above, the rocker arm 9 and the second rocker arm 9 are connected to the rocker arm 9 through the second connecting pin 13 that is normally movable in a predetermined position but cannot be rotated, although it is movable along the long hole-shaped pin insertion hole 21. The link 11 is connected so as to be relatively rotatable, and the second connecting pin 13, the adjusting bolt 22 and the lock bolt 23 form a lift amount adjusting means.

  In order to adjust the valve lift amount of the variable lift / operating angle mechanism 3 as described above, the link length of the second link 11 connecting the rocker arm 9 and the swing cam 5 is adjusted.

  Prior to this, after the control shaft 7 is indexed to the rotational position where the lift amount of each lift / working angle variable mechanism 3 is minimized, the drive shaft 4 is rotated at a low speed, and each lift / working angle at that time is variable. The lift amount for each mechanism 3 is measured in advance, and the necessary lift adjustment amount is grasped in advance.

  Subsequently, as shown in FIG. 3, the hexagonal socket 34 is fitted to the head 27 of the lock bolt 23 and then loosened by rotating the hexagonal socket 34 in the major axis direction of the elongated pin insertion hole 21. While giving the degree of freedom of the position of the second connecting pin 13, the bit 28 is inserted from the lock bolt 23 side and fitted into the hexagonal hole 26 of the adjusting bolt 22. Then, the adjustment bolt 22 is rotated by a predetermined amount in the forward rotation direction or the reverse rotation direction, that is, the adjustment bolt 22 is rotated by an amount necessary for the lift adjustment amount grasped in advance, and the second connecting pin After adjusting the position of 13, the lock bolt 23 is tightened again to fix the second connecting pin 13. By doing so, the link length of the second link 11 connecting the rocker arm 9 and the swing cam 5, that is, the distance between the shaft centers of the second connecting pin 13 and the third connecting pin 14 is changed. As a result, the lift amount and operating angle of the lift / operating angle variable mechanism 3 can be adjusted.

  Thus, according to the lift / operating angle variable mechanism 3, it is considered that the rotation operation of the lock bolt 23 by the socket 34 and the rotation operation of the adjustment bolt 22 by the bit 28 can be performed from the same or a single direction. Therefore, the lift amount can be adjusted very easily.

  Here, even if the lift amount is adjusted with the lift / operating angle variable mechanism 3 alone as described above, the cylinder head 1 on which the lift / operating angle variable mechanism 3 is mounted is bolted to the cylinder block. In this case, the cylinder head 1 may bend due to the influence of the bolt tightening force, and the previously adjusted lift amount may vary. Therefore, it is necessary to guarantee actual measurement of the lift amount even when the cylinder head 1 is assembled to the cylinder block, that is, in the state of the bare engine. In addition, in the state of the bare engine, as described above, it means a state in which the intake system, exhaust system, and electrical components are removed from the engine assembly including the cylinder head 1 and the cylinder block as main elements. If the crankshaft is driven to rotate, the pistons and valves move normally, and air can be sucked and exhausted.

  FIG. 8 shows an example of a system for measuring the lift amount in the state of the bare engine E. The bare engine E is mounted on the test bench 40 via the transfer jig 41 and positioned. Thus, the motoring device 42 and the measuring jig 43, which are rotational driving means, are coupled to the positioned bear engine E, respectively.

  The motoring device 42 has an electric motor 44 with a speed reducer as a main element, and the motor output shaft is coupled to the crankshaft of the bear engine E through a coupling 45.

  Further, the measuring jig 43 includes a pair of, for example, a reflection type laser displacement sensor 46 equal to the number of the intake valves 2 for one cylinder as a non-contact type displacement sensor at a pitch equal to the pitch between the intake valves 2 and 2. The measurement jig 43 itself is fixed to the bear engine E using, for example, a rocker cover mounting hole, and the measurement jig 43 itself is correctly positioned and fixed to the bear engine E. As shown in FIG. 9, the laser light emitted from each laser displacement meter 46 is directed to a part of the crown portion 17 a of the valve lifter 17 attached to the corresponding intake valve 2.

  The crown portion 17a of the valve lifter 17 refers to the circular top surface of the valve lifter 17 with which the swing cam 5 is pressed. Further, even if a complicated cam mechanism as shown in FIGS. 2 and 4 is arranged on the upper side of each valve lifter 17, a part of the cam mechanism interferes with the irradiation and reflection of the laser beam from the laser displacement meter 46. Without this, it is sufficient for the measurement intended in the present embodiment if an area of about 3 mm necessary for the irradiation and reflection of the laser beam can be secured in the crown portion 17a of the valve lifter 17.

  In addition, the electromagnetic coil 49 connected to the power supply 48 as a valve magnetizing means is mounted on the cylinder head 1 at a position corresponding to each intake port 47 shown in FIG. . Only the yoke 49a of the electromagnetic coil 49 is inserted from the intake port 47, and the tip of the yoke 49a is opposed to the outer peripheral surface of the valve stem 2a of the intake valve 2. In consideration of the actual lift operation of the intake valve 2, the tip of the yoke 49a does not come into contact with the valve stem 2a, and a clearance of about 5 mm, for example, is secured as a clearance α (see FIG. 9) between them. And

  The combined use of the electromagnetic coil 49 is intended to correct the relative positional relationship between the valve stem 2a and the valve lifter 17 with a magnetic adsorption force by magnetizing the intake valve 2. Before the lift operation, the electromagnetic coil 49 is energized, the magnetic force generated by the yoke 49a is applied to the intake valve 2, and the valve lifter 17 is attracted and supported by the stem end 2b by the magnetic attraction generated by the valve stem 2a. It is.

  This is because, as a special feature of the lift / operating angle variable mechanism 3, the pressing force exerted on the valve lifter 17 by the swing cam 5 based on the cam displacement of the swing cam 5 starts from the center of the crown portion 17 a of the valve lifter 17. If the valve lifter 17 falls down with respect to the shaft center of the valve stem 2a as shown in FIG. 10A due to the offset load, the crown portion 17a of the valve lifter 17 is likely to become unbalanced. This is because the measurement error of the lift amount measurement with the surface to be measured increases, and improvement in measurement accuracy cannot be expected.

  On the other hand, as shown in FIG. 5B, when the electromagnetic lift 49 described above is used in combination, the valve lifter 17 is attracted to the stem end by the magnetic attraction force generated by the valve stem 2a and corrected. Even if the intake valve 2 is actually lifted, the so-called tilting behavior β of the valve lifter 17 becomes minimal, and as a result, the measurement error of the lift amount measurement using the crown portion 17a of the valve lifter 17 as the measured surface. And the measurement accuracy can be improved. As a result of experiments conducted by the inventor, it has been confirmed that a necessary and sufficient effect can be obtained if a magnetic force of 375 Gauss or more is generated at the stem end of the valve stem 2a.

  In addition, what is shown with the code | symbol 60 in FIG. 9, 10 is a valve seat.

  Therefore, in the lift amount measurement by the laser displacement meter 46, as shown in FIG. 9 in addition to FIGS. 2 and 4, the lift amount of the lift / operating angle variable mechanism 3 of the cylinder for which the lift amount is to be measured is minimized. After the control shaft 7 is determined at the rotational position, the electromagnetic coil 49 is energized. As a result, as described above, the valve lifter 17 is adsorbed by the magnetic attractive force generated by the valve stem 2a of the intake valve 2, and the posture or behavior of the valve lifter 17 is corrected. At the same time, the laser light emitted from the light emitting portion of the laser displacement meter 46 irradiates the crown portion 17a of the valve lifter 17, and the reflected light from the crown portion 17a is correctly received by the light receiving portion of the laser displacement meter 46. Check it.

  Then, in a state where the posture or behavior of the valve lifter 17 is corrected, the crankshaft is rotationally driven by the activation of the motoring device 42, so that the drive shaft 4 is rotationally driven at a low speed. As the drive shaft 4 rotates, the swing cam 5 causes the intake valve 2 to actually lift through the valve lifter 17, so the output of the laser displacement meter 46 during the rotation of the drive shaft 4 is amplified by the amplifier 50. After that, it is continuously captured and recorded or stored in a data recorder 51 configured with, for example, a personal computer. As a result, as shown in FIG. 10B, in a state where the posture or behavior of the valve lifter 17 is corrected, the displacement with the crown portion 17a as the measurement surface continues as the actual lift amount of the intake valve 2. Is actually measured and the measured data is collected by the data recorder 51. Note that the waveform is displayed on the monitor screen or printed out as shown in FIG. 8 based on the data recorded or stored as necessary.

  When the lift amount measurement for the intake valve 2 for one cylinder is thus completed, the pair of laser displacement meters 46 are shifted to the next cylinder to be measured, and thereafter the same as above. Repeat the operation.

  In addition, it is desirable to perform demagnetization processing of each intake valve 2 after valve lift amount measurement.

  As described above, according to the present embodiment, it is possible to measure the actual lift amount that has been conventionally difficult for the bear engine E having the variable lift / operating angle mechanism 3 as the displacement of the crown portion 17a of the valve lifter 17. In addition, by correcting the posture or behavior of the valve lifter 17 with the magnetic attraction force, the influence of the so-called tilt β of the valve lifter 17 as shown in FIG. 10A on the measurement accuracy can be minimized. As a result, the lift amount can be measured with high accuracy.

  Here, in the above-described embodiment, an example of valve lift amount measurement for the lift / operating angle variable mechanism 3 is shown, but the present invention is a valve operating for a general internal combustion engine other than the lift / operating angle variable mechanism 3. Needless to say, the present invention can also be applied to the measurement of the valve lift of the system. In the above-described embodiment, if the lift amount measurement of the two intake valves 2 of the same cylinder is simultaneously performed by the pair of laser displacement meters 46, the pair of laser displacement meters 46 is subsequently used as the intake valve of the next cylinder. Although the same measurement is performed by shifting to the second side, the laser displacement meter 46 may be arranged in advance for the total number of intake valves 2. Further, it is of course possible to use another non-contact type or optical type displacement meter in place of the laser displacement meter 46.

Plane explanatory drawing of the cylinder head provided with the lift and the working angle variable mechanism as a variable valve mechanism. Cross-sectional explanatory drawing which follows the AA line of FIG. The principal part expansion explanatory drawing of FIG. FIG. 4 is a perspective view of the lift / operating angle variable mechanism of FIG. The principal part disassembled perspective view of FIG. The top view of the rocker arm shown in FIG. Sectional drawing in the coupling | bonding state of the rocker arm shown in FIG. 5, and a 2nd link. Configuration explanatory drawing which shows the outline of the valve lift amount measuring system of the bear engine provided with the cylinder head of FIGS. The principal part enlarged view of FIG. FIG. 10 is a diagram showing a change in measurement accuracy due to the influence of the valve lifter in the state of FIG. 9, (A) is an explanatory diagram when the posture or behavior of the valve lifter is not corrected, and FIG. Explanatory drawing at the time of correct | amending the attitude | position or behavior of a valve lifter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylinder head 2 ... Intake valve 2a ... Valve stem 3 ... Lift / operation angle variable mechanism (variable valve mechanism)
4 ... Drive shaft (camshaft)
5 ... Oscillating cam 5a, 5b ... Cam body 6 ... Eccentric cam (drive cam)
7 ... Control shaft 8 ... Eccentric cam 9 ... Rocker arm 10 ... First link (first link member)
11 ... 2nd link (2nd link member)
12 ... 1st connection pin 13 ... 2nd connection pin (lift amount adjustment means)
DESCRIPTION OF SYMBOLS 14 ... 3rd connection pin 17 ... Valve lifter 17a ... Crown part 18 ... Valve spring 22 ... Adjustment bolt (lift amount adjustment means) as an adjustment screw
23 ... Lock bolt as a lock screw (lift amount adjusting means)
42 ... Motoring device (rotation drive means)
43 ... Measurement jig 46 ... Laser displacement meter (non-contact displacement meter)
47 ... Intake port 49 ... Electromagnetic coil (valve magnetizing means)
49a ... Yoke E ... Bear engine

Claims (9)

A method for measuring a valve lift amount of an internal combustion engine,
While rotating the camshaft in a state where the relative positional relationship between the valve stem and the valve lifter is corrected with magnetic adsorption force by magnetizing the valve,
A valve lift amount measuring method for an internal combustion engine, characterized in that a crown portion of a valve lifter is measured and a displacement of the crown portion is measured as a valve lift amount with a non-contact displacement meter. Adhere the valve lifter to the stem end of the valve stem,
2. The valve lift amount of the internal combustion engine according to claim 1, wherein the relative positional relationship between the valve stem and the valve lifter is corrected so that the tilt of the shaft center of the valve lifter with respect to the valve stem is minimized. Measurement method.   3. The valve lift amount measuring method for an internal combustion engine according to claim 1, wherein the valve stem of the valve is magnetized by the valve magnetizing means through the intake port or the exhaust port. The valve magnetizing means is an electromagnetic coil,
4. A valve lift amount measuring method for an internal combustion engine according to claim 3, wherein the valve stem is magnetized by inserting a yoke of an electromagnetic coil from the intake port or the exhaust port and bringing the yoke close to the valve stem. .   5. The valve lift amount measuring method for an internal combustion engine according to claim 1, wherein the non-contact type displacement meter is a laser displacement meter. A valve lift amount measuring apparatus for an internal combustion engine used for valve lift amount measurement according to claim 1,
Rotational drive means for rotationally driving the camshaft;
A valve magnetizing means for correcting the relative positional relationship between the valve stem and the valve lifter with a magnetic adsorption force by magnetizing the valve;
A non-contact displacement meter that measures the displacement of the crown as a valve lift amount with the crown of the valve lifter as the surface to be measured;
An apparatus for measuring a valve lift amount of an internal combustion engine, comprising:   The above valve magnetizing means adsorbs the valve lifter to the stem end of the valve stem and corrects the relative positional relationship between the valve stem and the valve lifter so that the tilt of the valve lifter shaft center relative to the valve stem is minimized. The valve lift amount measuring apparatus for an internal combustion engine according to claim 6, wherein   The valve magnetizing means is an electromagnetic coil, wherein a yoke of the electromagnetic coil is inserted from an intake port or an exhaust port, and the valve stem is magnetized by bringing the yoke close to the valve stem. Item 8. A valve lift amount measuring apparatus for an internal combustion engine according to Item 7.   The valve lift amount measuring apparatus for an internal combustion engine according to any one of claims 6 to 8, wherein the non-contact displacement meter is a laser displacement meter.

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