JP5164071B2 - Valve control device, engine and motorcycle - Google Patents

Description

  The present invention relates to a valve control device, an engine, and a motorcycle, and more specifically, a valve control device, an engine, and a motorcycle that switch a valve lift amount to a first lift amount or a second lift amount larger than the first lift amount. About.

  For engines such as motorcycles and automobiles, when the engine speed (speed) is low (low speed operation), the valve is opened small (lift amount is reduced), and when the engine speed is high (high speed operation), the valve is opened. A variable valve mechanism that opens the valve (increases the lift amount) is employed. Specifically, a low speed cam with a small amount of displacement and a high speed cam with a large amount of displacement are provided around the camshaft. The variable valve mechanism is configured to switch to a low speed cam at low speed and to switch to a high speed cam at high speed. As a result, the valve is driven small by the low-speed cam at low speed, and is driven largely by the high-speed cam at high speed.

  In such a valve operating control apparatus that controls the variable valve operating mechanism, the threshold of the engine speed at which the cam is switched is prevented so as not to cause hunting in which the low speed cam and the high speed cam are frequently switched in a short time when the cam is switched. The value is provided with hysteresis. Specifically, as shown in FIG. 20, two types of threshold values VL and VH are provided on the low speed side and the high speed side. When the engine speed falls below the low speed side threshold value VL, the valve is switched to the low speed cam when the valve is driven by the high speed cam, and is maintained as it is when the valve is driven by the low speed cam. On the other hand, when the engine speed exceeds the high speed side threshold value VH, the valve is switched to the high speed cam when the valve is driven by the low speed cam, and is maintained as it is when the valve is driven by the high speed cam.

  Incidentally, when the engine speed instantaneously falls below the low speed side threshold VL, the engine speed may instantaneously exceed the high speed side threshold VH (see section A in FIG. 20). In this case, there is a problem that the low speed cam and the high speed cam are frequently switched in a short time. If the hysteresis (difference between threshold values VL and VH) is further increased, this problem can be solved. However, there arises a new problem that the responsiveness of the cam switching is deteriorated.

In particular, since motorcycles turn by tilting the vehicle body, the engine speed tends to fluctuate. The speed (vehicle speed) of a motorcycle is expressed by the following equation.
Vehicle speed (km / h) = engine speed (rpm) / total reduction ratio x 2π x effective tire diameter (m) x (60/1000)

  As shown in FIG. 21A, since the vehicle body stands upright when traveling straight, the effective tire diameter is maximized. On the other hand, as shown in FIG. 21 (b), since the vehicle body is inclined during the turn, the effective tire diameter is reduced. If the effective tire diameter changes when the vehicle speed is constant, the engine speed changes, so the engine speed changes greatly in a short time during a turn (see section B in FIG. 22).

  In addition, since a motorcycle generally uses a chain for driving rear wheels, the engine speed tends to fluctuate due to chain play. This is because the upper chain is stretched during acceleration and the lower chain is slack, whereas the reverse occurs during deceleration. Furthermore, since the inertia of the engine itself is small in a two-wheeled vehicle and the vehicle body is lighter than that of a four-wheeled vehicle, the fluctuation of the engine rotation speed becomes large.

  Japanese Patent Laying-Open No. 2005-042607 (Patent Document 1) describes a valve control apparatus that can switch between a low speed cam and a high speed cam at an appropriate timing while suppressing frequent switching feeling and ensuring acceleration feeling. Has been. This valve control apparatus is configured not to immediately perform switching when it is determined that the cam should be switched, but to delay the execution.

According to this valve control apparatus, even when the engine speed fluctuates instantaneously as described above, the cam does not frequently switch in a short time. However, since the switching of the cam is intentionally delayed, the responsiveness of the lift amount switching is inevitably deteriorated.
JP 2005-042607 A

  An object of the present invention is to provide a valve operating control device, an engine, and a motorcycle that prevent the lift amount from frequently switching in a short time even when the engine rotational speed fluctuates greatly while maintaining the responsiveness of the lift amount switching. Is to provide.

Means for Solving the Problems and Effects of the Invention

  A valve operating control apparatus according to the present invention is a valve operating control apparatus that switches a valve lift amount to a first lift amount or a second lift amount that is larger than the first lift amount. Provided with threshold value changing means. The lift amount switching means sets the valve lift amount to the second lift amount when the engine speed falls below the first threshold value when the valve lift amount is switched to the second lift amount. When the valve lift amount is switched to the first lift amount, the engine speed exceeds the second threshold value which is higher than the first threshold value. The valve lift amount is switched from the first lift amount to the second lift amount. The threshold value changing means temporarily increases the second threshold value when the lift amount of the valve is switched from the second lift amount to the first lift amount by the lift amount switching means, and the lift amount is switched. When the valve lift amount is switched from the first lift amount to the second lift amount by the means, the first threshold value is temporarily lowered.

  According to the present invention, even if the engine speed instantaneously falls below the first threshold value and the engine speed instantaneously exceeds the second threshold value, the lift amount is the second lift amount. When the first lift amount is switched to the second threshold value, the second threshold value temporarily increases. Similarly, when the engine speed exceeds the second threshold value, the first threshold value is temporarily lowered when the lift amount is switched from the first lift amount to the second lift amount. Become. Therefore, the lift amount does not change frequently in a short time. In addition, since the hysteresis that is the difference between the first threshold value and the second threshold value is not increased, the responsiveness of the lift amount switching is not deteriorated.

  In one embodiment of the present invention, the threshold value changing means is configured such that when the lift amount of the valve is switched from the second lift amount to the first lift amount by the lift amount switching means, the second threshold value is changed. Is increased by a predetermined amount from the initial value, then the second threshold value is gradually lowered to return to the initial value, and the lift amount of the valve is changed from the first lift amount to the second lift amount by the lift amount switching means. When the first threshold value is switched, the first threshold value is lowered by a predetermined amount from the initial value, and then the first threshold value is gradually increased to return to the initial value.

  In another embodiment of the present invention, when the lift amount of the valve is switched from the second lift amount to the first lift amount by the lift amount switching means, the threshold value changing means is for a predetermined time. When the second threshold value is increased by a predetermined amount and the lift amount of the valve is switched from the first lift amount to the second lift amount by the lift amount switching means, the first threshold is maintained for a predetermined time. Decrease the value by a predetermined amount.

  The valve operating control device is provided in an engine, for example. The engine is provided in, for example, a motorcycle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[First Embodiment]
(1) Overall Configuration of Motorcycle With reference to FIG. 1, a motorcycle 100 including a valve operating control device according to an embodiment of the present invention includes a main frame 1. A head pipe 2 is provided at the front end of the main frame 1. A front fork 3 is rotatably provided on the head pipe 2. A front wheel 4 is rotatably supported at the lower end of the front fork 3. A handle 5 is attached to the upper end of the front fork 3.

  A cowl 6 is provided so as to cover the front and side of the main frame 1. A DOHC (Double Over Head Camshaft) engine 7 is provided in the center of the main frame 1. An air cleaner box 8 is provided above the engine 7. An intake pipe 10 is provided so as to connect the air cleaner box 8 and the intake port 9 of the engine 7.

  An intake passage 11 that connects the air cleaner box 8 and the outside is provided at the front portion of the motorcycle 100 so as to be covered with the cowl 6. One end of the intake passage 11 is open at the front surface of the cowl 6. Air outside the motorcycle 100 is taken into the engine 7 through the intake passage 11, the air cleaner box 8 and the intake pipe 10.

  One end of an exhaust pipe 13 is connected to the exhaust port 12 of the engine 7. The other end of the exhaust pipe 13 is connected to the muffler device 14. Burned gas generated by the combustion of the mixer in the engine 7 is discharged to the outside through the exhaust pipe 13 and the muffler device 14.

  A seat 15 is provided on the upper portion of the engine 7. An ECU (Electronic Control Unit) 16 that controls the operation of each part of the motorcycle 100 is provided below the seat 15. Details of the ECU 16 will be described later. A rear arm 17 is connected to the main frame 1 so as to extend rearward of the engine 7. The rear arm 17 rotatably holds the rear wheel 18 and the rear wheel driven sprocket 19. A chain 20 is attached to the rear wheel driven sprocket 19. The power generated by the engine 7 is transmitted to the rear wheel driven sprocket 19 via the chain 20. Thereby, the rear wheel 18 rotates.

(2) Configuration of Engine and Variable Valve Mechanism The engine 7 includes a variable valve mechanism that switches the lift amounts of the intake and exhaust valves to two stages, low speed and high speed. Specifically, referring to FIGS. 2 and 3, the engine 7 includes a cylinder 701, a cylinder head 702 that is detachably attached to the cylinder 701, and a cam carrier 703 that is detachably attached to the cylinder head 702. Is provided. For example, in the case of a four-cylinder engine, four cylinders 701 are arranged in series. The engine 7 has basically the same structure for each cylinder. Hereinafter, description will be given focusing on one cylinder.

  Referring to FIG. 2, the cylinder head 702 includes an intake port 9, an exhaust port 12, an intake valve 22, an exhaust valve 24, valve springs 26 and 28, and valve spring accommodating spaces 30 and 32. This engine is a four-valve system, and two intake valves 22 and two exhaust valves 24 are provided. The valve springs 26 and 28 are wound around the rods 34 and 36 of the intake and exhaust valves 22 and 24, respectively, and are accommodated in the valve spring accommodating spaces 30 and 32, respectively. A partition wall 37 is formed between the intake side valve spring accommodating space 30 and the exhaust side valve spring accommodating space 32. Referring to FIG. 3, a partition wall 38 is also formed between the two intake side valve spring accommodating spaces 30. Although not shown because it is the same as FIG. 3, a partition wall is also formed between the two exhaust side valve spring accommodating spaces 32. The partition wall 38 in this example has the same thickness everywhere, but the thickness may differ depending on the location.

  Referring to FIGS. 2 and 4 to 8, cam carrier 703 includes cam bearing portions 44 and 46 that rotatably support two camshafts 40 and 42, and a rocker that supports rocker shafts 48 to 51. A shaft support portion 52 and hydraulic cylinder support portions 43 and 45 are provided. The cam bearing portions 44 and 46, the rocker shaft support portion 52, and the hydraulic cylinder support portions 43 and 45 are integrally configured. 4 and 6, the cam bearing portions 44 and 46 are arranged side by side on a straight line 55 in a plane perpendicular to the camshafts 40 and 42 through the bore center 53 (center of the cylinder 701). The cam carrier 703 is individually formed for each cylinder. Therefore, in the case of a 4-cylinder engine, four cam carriers 703 are provided. The camshafts 40 and 42 are commonly supported by four cam carriers 703 arranged in a straight line.

  7 and 8, the cam bearing portions 44 and 46 have semicircular cutouts 54 and 56, respectively, on which the camshafts 40 and 42 lie. The camshafts 40 and 42 have a low speed cam 39 with a small displacement amount and a high speed cam 41 with a large displacement amount. Holders 62 and 64 having notches 58 and 60 symmetrical to the notches 54 and 56 are attached to the cam bearing portions 44 and 46 with bolts 66 and 67 so as to sandwich the camshafts 40 and 42. Thereby, the camshafts 40 and 42 are rotatably supported.

  4 to 8, the rocker shaft support portion 52 includes a rectangular parallelepiped center portion 68, plate-like end portions 70 and 72, and a connecting portion that connects the center portion 68 and the end portions 70 and 72. 74. A circular through hole 78 is formed in the central portion 68 so that the spark plug 76 can be attached to and detached from the cylinder head 702. Rocker shafts 48 to 51 are attached to the rocker shaft support portion 52 in parallel with the camshafts 40 and 42. Four rocker shafts 48 to 51 are provided corresponding to the four valves 22 and 24. Specifically, the rocker shafts 48 and 50 are bridged between the central portion 68 and the end portion 70. The rocker shafts 49 and 51 are bridged between the central portion 68 and the end portion 72. The rocker shafts 48 and 50 are abutted with the rocker shafts 49 and 51 in the central portion 68, respectively. Within the central portion 68, the rocker shafts 48 to 51 are cut out in an arc shape along the through hole 78.

  2 to 8, low-speed rocker arms 80 to 83 are swingably supported on the rocker shafts 48 to 51. Four low-speed rocker arms 80 to 83 are provided corresponding to the four valves 22 and 24. The tip portions of the low-speed rocker arms 80 to 83 push the shaft end surfaces 79 of the intake and exhaust valves 22 and 24. The low-speed rocker arms 80 and 81 swing according to the low-speed cam 39 of the intake side camshaft 40, thereby pushing down the intake valve 22 directly. The low-speed rocker arms 82 and 83 swing according to the low-speed cam 39 of the exhaust side camshaft 42, thereby pushing down the exhaust valve 24 directly.

  High-speed rocker arms 84 to 87 are also swingably supported on the rocker shafts 48 to 51. Four high-speed rocker arms 84 to 87 are also provided corresponding to the four valves 22 and 24. The high speed rocker arms 84 to 87 are adjacent to the low speed rocker arms 80 to 83, respectively. The high-speed rocker arms 84 and 85 swing according to the high-speed cam 41 of the intake side camshaft 40. The high-speed rocker arms 84 and 85 do not push the intake valve 22 directly. The high speed rocker arms 86 and 87 swing according to the high speed cam 41 of the exhaust side camshaft 42. The high-speed rocker arms 86 and 87 do not push down the exhaust valve 24 directly.

  With reference to FIGS. 6 and 7, the low-speed rocker arms 80 to 83 are arranged on the cam bearing portions 44 and 46 side of the high-speed rocker arms 84 to 87, and have circular through holes 88. The through hole 88 is formed in parallel with the rocker shafts 48 to 51. A cylindrical connecting pin 90 is slidably inserted into the through hole 88.

  Referring to FIG. 7, the engine 7 is also provided with an actuator 89 that reciprocates the connecting pin 90 in the through hole 88. Specifically, referring to FIGS. 3, 4, and 7, the actuator 89 includes a cylindrical hydraulic cylinder 92 and a columnar hydraulic piston 94.

  The connecting pin 90 has a circular flange 96 at its head. A spring 98 is wound around the connecting pin 90. The connecting pin 90 is slidably inserted into the through hole 88 from the bottom. Therefore, the connecting pin 90 is biased toward the hydraulic cylinder support portions 43 and 45 side. Further, the length of the connecting pin 90 is longer than the length of the through hole 88. Therefore, when the connecting pin 90 is pushed into the through hole 88 to the end, the bottom of the connecting pin 90 protrudes from the opposite side of the through hole 88.

  The hydraulic cylinder 92 is provided in the hydraulic cylinder support portions 43 and 45. Specifically, a circular through hole 99 is formed below the notch 54 of the cam bearing portions 44 and 46. The hydraulic cylinder 92 is fitted in the through hole 99 and fixed in the hydraulic cylinder support portions 43 and 45.

  In this example, a through hole 99 for the hydraulic cylinder 92 is formed in the hydraulic cylinder support portions 43 and 45, and the hydraulic cylinder 92 is fitted into the through hole 99, but nothing is fitted into the through hole 99, and the through hole 99 is inserted. Can also be used as a hydraulic cylinder.

  In this example, the hydraulic pistons 94 on both sides are inserted into the hydraulic cylinder 92 fitted in the common through hole 99. However, two independent non-through holes having different axial centers may be formed from both sides of the hydraulic cylinder support portion, and the hydraulic cylinder may be inserted into these non-through holes. In this case, since the hydraulic cylinders are arranged in a direction perpendicular to the camshaft, the width of the hydraulic cylinder support portion can be further reduced.

  The hydraulic piston 94 has a circular rod 102 at its head. The hydraulic piston 94 is slidably inserted into the hydraulic cylinder 92 from its bottom. The head portion (102) of the hydraulic piston 94 comes into contact with the head portion (鍔 96) of the connecting pin 90.

  Thus, since the hydraulic cylinder 92 and the hydraulic piston 94 are disposed below the cam bearing portions 44 and 46, the actuator 89 can be mounted in a compact manner even in a small engine having a narrow valve spring. In the case of this example, as shown in FIG. 3, the hydraulic cylinder support 43 is wider than the interval between the two intake side valve springs 26. That is, the thickness D1 of the hydraulic cylinder support portion along the axial direction of the camshaft 40 is larger than the outer diameter interval D2 of the valve spring 26.

  With reference to FIGS. 6 to 8, the high-speed rocker arms 84 to 87 have a hook portion 104 that is hooked with the buttocks of the connecting pin 90 protruding from the through hole 88. The catching part 104 is a semicircular cutout, and the connecting pin 90 is engaged with it.

  Referring to FIGS. 2, 7, and 8, a lost motion spring shaft 106 is attached to the rocker shaft support portion 52 in parallel with the camshafts 40 and 42. Four lost motion spring shafts 106 are provided corresponding to the four valves 22, 24. Specifically, the lost motion spring shaft 106 is bridged between the central portion 68 and the end portions 70 and 72. A lost motion spring 108 is wound around the lost motion spring shaft 106 and hooked to the high speed rocker arms 84 to 87 and the connecting portion 74. Specifically, each of the high-speed rocker arms 84 to 87 has a latching portion 110 cut out in a semicircular shape, and one end of the lost motion spring 108 is latched here. The connecting portion 74 has a latching portion 112 that is perforated in a rectangular shape, and the other end of the lost motion spring 108 is latched thereon. Accordingly, the high speed rocker arms 84 to 87 are biased toward the high speed cam 41.

  Referring to FIG. 2, on the intake side, the axis of the lost motion spring shaft 106 is connected to the axis of the intake camshaft 40, the axis of the rocker shaft 48, and the center point of the shaft end surface 79 of the intake valve 22. Arranged outside the range. On the exhaust side, the axis of the lost motion spring shaft 106 is the center of the axis of the exhaust camshaft 42, the axis of the rocker shaft 50, and the shaft end face (shaft end face) 79 of the exhaust valve 24. Arranged outside the connected area.

  With reference to FIGS. 2 and 4 to 6, the cam carrier 703 is attached to the cylinder head 702 with bolts 67 and 114. With reference to FIGS. 5 and 6, the lower surfaces 116 of the cam bearing portions 44 and 46 are joined to the upper surface 118 of the cylinder head 702. A groove 120 communicating with the hydraulic cylinder 92 is formed on the lower surface 116 of the cam bearing portions 44 and 46. The groove 120 constitutes an oil passage. Referring to FIG. 7, hydraulic cylinder 92 has an opening 122 communicating with groove 120. Accordingly, oil sent from a hydraulic pump (not shown) flows from the groove 120 through the opening 122 into the hydraulic cylinder 92 via an OCV (Oil Control Valve) 139 (FIG. 9). Each groove 120 feeds oil to both sides and pushes out hydraulic pistons 94 on both sides. That is, each groove 120 is shared by the hydraulic pistons 94 on both sides thereof.

  Since the groove 120 opens to the lower surface 116 side, it is easier to form the groove 120 than the hole. The groove 120 may be formed on the upper surface 118 of the cylinder head 702 instead of the lower surface 116 of the cam carrier 703. The groove 120 in this example is straight, but may be bent. Even if it is bent in a complicated manner, it can be easily formed because it is a groove.

  With reference to FIGS. 2, 5, and 7, the central portion 68 and the end portions 70 and 72 of the rocker shaft support portion 52 have a convex portion 124 that protrudes from the lower surface 116 of the cam bearing portions 44 and 46. The rocker shafts 48 to 51 are attached to the convex portion 124.

  At high speed, by opening the OCV 139 on the oil passage, the hydraulic pressure in the groove 120 is increased, and the hydraulic piston 94 is pushed outward. In response to this, the connecting pin 90 is pushed and moved into the through holes 88 of the low-speed rocker arms 80 to 83. Thereby, the bottom of the connecting pin 90 jumps out from the opposite side of the through hole 88. Since the high-speed rocker arms 84 to 87 are urged in the direction of the high-speed cam 41 by the lost motion spring 108, the hook 104 is engaged with the connecting pin 90 protruding from the through hole 88. Therefore, the low-speed rocker arms 80 to 83 and the high-speed rocker arms 84 to 87 are connected. When the high-speed rocker arms 84 to 87 are largely swung according to the high-speed cam 41 having a large displacement, the low-speed rocker arms 80 to 83 are also largely swung together with the high-speed rocker arms 84 to 87. In response to this, the low-speed rocker arms 80 to 83 push and move the intake or exhaust valves 22 and 24 on the shaft end surface 79, and the intake or exhaust valves 22 and 24 are opened largely.

  On the other hand, at low speed, the OCV 139 on the oil passage is closed to lower the hydraulic pressure in the groove 120, and the connecting pin 90 is pushed back toward the hydraulic cylinder support portions 43 and 45 by the elastic force of the spring 98. As a result, the hydraulic piston 94 is pushed into the hydraulic cylinder 92, and the bottom of the connecting pin 90 is completely accommodated in the through hole 88. Therefore, the low-speed rocker arms 80 to 83 and the high-speed rocker arms 84 to 87 are separated. When the low-speed rocker arms 80 to 83 are oscillated small according to the low-speed cam 39 having a small displacement amount, the low-speed rocker arms 80 to 83 push and move the intake or exhaust valves 22 and 24 by the shaft end surface 79. Open 24 small. At this time, the high-speed rocker arms 84 to 87 are greatly swung according to the high-speed cam 41, but the high-speed rocker arms 84 to 87 do not push anything because the bottom of the connecting pin 90 does not protrude from the through hole 88 ( I will shake it).

(3) Configuration of ECU (Valve Control Unit) Next, the configuration of a valve control unit that controls the variable valve mechanism in the ECU 16 will be described with reference to FIG.

  The ECU 16 includes an engine speed calculation unit 131, a cam switching determination unit 132, and memories 133a to 133g. The engine speed calculation unit 131 and the cam switching determination unit 132 are realized by causing a computer to execute a predetermined program.

  The engine speed calculation unit 131 calculates the engine speed based on the crank angle of the engine 7 detected by the crank angle sensor 136.

  The memory 133a stores the switching determination map 137 illustrated in FIG. In the switching determination map 137, predetermined cam switching determination values are set for each engine speed and each throttle opening. When the engine speed and the throttle opening are determined, the corresponding cam switching determination value is determined.

  9 switches the lift amount of the intake and exhaust valves 22 and 24 to the low-speed cam 39 or the high-speed cam 41. Specifically, the cam switching determination unit 132 has a lift amount switching function and a threshold value changing function. The lift amount switching function switches the cam from the high speed cam 41 to the low speed cam 39 when the rotational speed of the engine 7 falls below the low speed cam switching threshold VL when the cam is switched to the high speed cam 41. The lift amount switching function also enables the cam to be switched when the rotational speed of the engine 7 exceeds the high speed cam switching threshold VH that is higher than the low speed cam switching threshold VL when the cam is switched to the low speed cam 39. The low speed cam 39 is switched to the high speed cam. The threshold value changing function temporarily increases the high speed cam switching threshold value VH when the cam is switched from the high speed cam 41 to the low speed cam 39. The threshold value changing function also temporarily lowers the low speed cam switching threshold value VL when the cam is switched from the low speed cam 39 to the high speed cam 41.

  In particular, in the first embodiment, the threshold value changing function increases the high-speed cam switching threshold value VH by a predetermined amount from the initial value when the cam is switched from the high-speed cam 41 to the low-speed cam 39. Thereafter, the high speed cam switching threshold is gradually lowered to return to the initial value. The threshold value changing function also lowers the low-speed cam switching threshold value VL gradually after reducing the low-speed cam switching threshold value VL by a predetermined amount from the initial value when the cam is switched from the low-speed cam 39 to the high-speed cam 41. Return to the initial value. Details of the cam switching determination unit 132 will be described later.

  The memory 133b stores a current cam state indicating whether the cam currently used for driving the intake and exhaust valves 22 and 24 is the low-speed cam 39 or the high-speed cam 41. The cam switching determination unit 132 refers to the switching determination map 137 stored in the memory 133a, and corresponds to the engine speed calculated by the engine speed calculation unit 131 and the throttle opening detected by the throttle opening sensor 138. The cam switching determination value is read to determine whether the cam should be switched, and the determination result is stored in the memory 133c. As a result of the determination by the cam switching determination unit 132, the memory 133c stores a requested cam state indicating whether the next cam to be used for driving the intake and exhaust valves 22 and 24 is the low speed cam 39 or the high speed cam 41. The cam switching determination unit 132 also controls the OCV 139 based on the determination result to switch between the low speed cam 39 and the high speed cam 41.

(4) Operation of the Valve Control Device The cam switching determination unit 132 is realized by causing a computer to execute a program including steps S1 to S13 illustrated in FIG. The computer executes this program every predetermined time (for example, 5 milliseconds).

  First, the computer executes a predetermined cam switching determination process (S1). The cam switching determination process is a process for determining whether or not to switch the cam based on the detected current engine speed and throttle opening.

  Specifically, as shown in FIG. 12, first, the current engine speed is detected from the engine speed calculation unit 131 (S21), and the current throttle opening is detected from the throttle opening sensor 138 (see FIG. 12). S22). These detection orders may be reversed.

  Next, the switching determination map 137 of the memory 133a is scanned, and the cam switching determination value corresponding to the detected current engine speed and throttle opening is read (S23).

  Next, information indicating the current cam state (hereinafter referred to as “current cam state”) set in the memory 133b is read (S24), and it is determined whether the currently used cam is the low-speed cam 39 or not (S24). S25).

  In the case of the low-speed cam 39 (YES in S25), in order to determine whether or not the low-speed cam 39 should be switched to the high-speed cam 41, the cam switching determination value read in step S23 is a predetermined high-speed cam switching. It is determined whether or not the threshold value is VH (for example, 6500 rpm) or more (S26). When the cam switching determination value is equal to or higher than the high-speed cam switching threshold VH (YES in S26), the high-speed cam 41 is set in the memory 133c as the requested cam state (the state where the cam should be determined from the engine operating state) ( S27). On the other hand, if the cam switching determination value is less than the high speed cam switching threshold VH (NO in S26), the current cam state (in this case, the low speed cam 39) is set in the memory 133c as the requested cam state (S28).

  As a result of the determination in step S25, in the case of the high speed cam 41 (NO in S25), in order to determine whether or not the high speed cam 41 should be switched to the low speed cam 39, the cam switching determination value read in step S23 is determined in advance. It is determined whether or not the speed is lower than a predetermined low speed cam switching threshold VL (for example, 6000 rpm) (S29). The low speed cam switching threshold VL is set lower than the high speed cam switching threshold VH. If the cam switching determination value is less than or equal to the low speed cam switching threshold VL (YES in S29), the low speed cam 39 is set in the memory 133c as the requested cam state (S30). On the other hand, when the cam switching determination value is higher than the low speed cam switching threshold VL (NO in S26), the current cam state (in this case, the high speed cam 41) is set in the memory 133c as the requested cam state (S28).

  Referring again to FIG. 11, it is determined whether or not the current cam state set in the memory 133b matches the requested cam state set in the memory 133c (S2). If they match (YES in S2), there is no need to switch the cam, and the process proceeds to step S11. If they do not match (NO in S2), the process proceeds to step S3 to switch the cam.

  In order to switch the cam, first, the cam switching thresholds VL and VH and the hysteresis immediately after the switching are initialized (S3). Specifically, the low speed cam switching threshold VL is set to an initial value (for example, 6000 rpm) and stored in the memory 133d. Further, the high-speed cam switching threshold value VH is set to an initial value (for example, 6500 rpm) and stored in the memory 133e. Further, the hysteresis immediately after switching is set to a predetermined initial value and stored in the memory 133g. The initial value of the hysteresis immediately after switching is determined by the processing shown in FIG.

  First, the amount of change per unit time (in this example, 1 second) of the engine speed detected in step S21 is calculated (S31). The memory 133f stores a hysteresis selection map 134 immediately after switching shown in FIG. With reference to this map 134, the hysteresis immediately after switching corresponding to the calculated amount of change in engine speed is selected (S32), and the hysteresis immediately after switching is updated by overwriting the memory 133g (S33). For example, when the amount of change in engine speed is 100 rpm / second, the hysteresis immediately after switching is set to 300 rpm.

  Referring to FIG. 11 again, it is determined whether or not the low speed cam 39 should be switched after the initialization is finished (S4).

  If the current cam state is the high speed cam 41 and the requested cam state is the low speed cam 39 (YES in S4), the OCV 139 is controlled to switch from the high speed cam 41 to the low speed cam 39 (S5). Next, the high-speed cam switching threshold value VH is read from the memory 133e, the hysteresis immediately after switching is read from the memory 133g, and the read hysteresis immediately after switching is added to the read high-speed cam switching threshold value VH (S6). ). Then, the current cam state is updated by rewriting the memory 133b from the high speed cam 41 to the low speed cam 39 (S7). Further, the high-speed cam switching threshold value VH is updated by overwriting the memory 133e with the addition result in step S6 (S8).

  On the other hand, when the current cam state is the low speed cam 39 and the requested cam state is the high speed cam 41 (NO in S4), the OCV 139 is controlled to switch from the low speed cam 39 to the high speed cam 41 (S9). Next, the low speed cam switching threshold value VL is read from the memory 133d, the hysteresis immediately after switching is read from the memory 133g, and the read hysteresis immediately after switching is subtracted from the read low speed cam switching threshold value VL (S10). ). Then, the current cam state is updated by rewriting the memory 133b from the low speed cam 39 to the high speed cam 41 (S7). Further, the low-speed cam switching threshold VL is updated by overwriting the memory 133d with the result of subtraction in step S10 (S8).

  If the result of determination in step S2 is that the current cam state matches the requested cam state (YES in S2), it is determined whether or not the hysteresis immediately after switching of the memory 133g is 0 (S11). If the hysteresis immediately after switching is 0 (YES in S11), the low-speed and high-speed cam switching thresholds VL and VH have already returned to the initial values, and thus this processing ends. On the other hand, if the hysteresis immediately after switching is not 0 (NO in S11), the low speed and high speed cam switching thresholds VL and VH have not yet returned to their initial values, and therefore a predetermined hysteresis return amount (for example, 5 rpm) from the hysteresis immediately after switching. Is subtracted (S12). Then, it is determined whether or not the current cam state of the memory 133b is the low speed cam 39 (S13). If the current cam state is the low-speed cam 39 (YES in S13), the process proceeds to step S6 to change the high-speed cam switching threshold value VH. When the current cam state is the high speed cam 41 (NO in S13), the process proceeds to step S10 in order to change the low speed cam switching threshold VL. Then, the hysteresis immediately after switching is updated by updating the low-speed or high-speed cam switching thresholds VL and VH and overwriting the memory 133g with the subtraction result in step S12 (S8).

  Since the valve operating control apparatus according to the first embodiment is configured as described above, as shown in FIG. 15, the engine speed instantaneously falls below the low-speed cam switching threshold VL, and the reaction occurs. Even if the engine speed instantaneously exceeds the high speed cam switching threshold value VH (initial value) (see section C in FIG. 15), when the cam is switched from the high speed cam 41 to the low speed cam 39, the high speed cam The switching threshold value VH temporarily increases. Similarly, when the engine speed exceeds the high-speed cam switching threshold value VH (see D in FIG. 15), when the cam is switched from the low-speed cam 39 to the high-speed cam 41, the low-speed cam switching threshold value VL. Is temporarily lower. Therefore, the low speed cam 39 and the high speed cam 41 are not frequently switched in a short time. In addition, since the hysteresis, which is the difference between the low speed cam switching threshold VL (initial value) and the high speed cam switching threshold VH (initial value), is not increased, the responsiveness of cam switching does not deteriorate. .

[Second Embodiment]
In the second embodiment of the present invention, the threshold changing function of the cam switching determination unit 132 shown in FIG. 1 differs from the first embodiment in that the cam changes from the high speed cam 41 to the low speed cam 39. When switched, the high-speed cam switching threshold VH is increased by a predetermined amount for a predetermined time. This threshold value changing function also lowers the low speed cam switching threshold VL by a predetermined amount for a predetermined time when the cam is switched from the low speed cam 39 to the high speed cam 41.

  The cam switching determination unit 132 according to the second embodiment is realized by causing a computer to execute a program including steps S1 to S15 illustrated in FIG. Steps different from those of the first embodiment are steps S3, S8, S11, S12, S14, and S15. Further, the memory 133g stores a time for which the hysteresis immediately after switching should be held instead of the hysteresis immediately after switching. This time is counted down as time passes from the initial value. Therefore, the memory 133g stores the remaining time for which hysteresis should be maintained immediately after switching.

  In step S3, as in the first embodiment, the low speed and high speed cam switching thresholds VL and VH are set to initial values, and unlike the first embodiment, the hysteresis immediately after switching is maintained. The power time is set to an initial value and stored in the memory 133g. This initial value is determined by the process shown in FIG.

  First, the amount of change per unit time of the engine speed is calculated (S41). The memory 133f stores a hysteresis selection map 135 immediately after switching shown in FIG. In this map 135, an initial value (predetermined holding time) of the time for which hysteresis should be held immediately after switching is registered in advance corresponding to the amount of change in the engine speed. With reference to this map 135, the hysteresis holding time immediately after switching corresponding to the calculated amount of change in engine speed is selected (S42), and thus the hysteresis holding time immediately after switching is updated by overwriting the memory 133g (S42). S43). For example, when the engine speed change amount is 100 rpm / second, the hysteresis holding time immediately after switching is set to 60 counts. If the count value is decremented every 5 milliseconds, 60 counts corresponds to 300 milliseconds.

  In step S14, the holding time is set, and the memory 133g is overwritten. Immediately after the cam switching, the holding time (initial value) initialized in step S3 is set, and thereafter, the remaining time (count value) decremented in step S12 is set.

  In step S8, only the low speed or high speed cam switching thresholds VL and VH are updated.

  In step S11, if the current cam state matches the requested cam state, it is determined whether or not the remaining time of the memory 133g is zero. When the remaining time is 0 (YES in S11), the low speed or high speed cam switching thresholds VL and VH are returned to the initial values (S15). If the remaining time is not 0 (NO in S11), the remaining time is decremented (S12).

  Since the valve operating control apparatus according to the second embodiment is configured as described above, as shown in FIG. 19, the engine speed instantaneously falls below the low-speed cam switching threshold VL, and the reaction occurs. Even if the engine speed instantaneously exceeds the high speed cam switching threshold value VH (initial value) (see section E in FIG. 19), when the cam is switched from the high speed cam 41 to the low speed cam 39, a predetermined time During this period, the high-speed cam switching threshold VH increases by a predetermined amount. Similarly, when the engine speed exceeds the high-speed cam switching threshold value VH (see F part in FIG. 19), when the cam is switched from the low-speed cam 39 to the high-speed cam 41, the low-speed cam for a predetermined time. The switching threshold VL is lowered by a predetermined amount. During the predetermined time, the low speed and high speed cam switching thresholds VL and VH are always constant.

[Other embodiments]
Instead of the two types of cams in the above embodiment (low speed cam 39 and high speed cam 41), one type of cam may be used, and the lift amount may be switched by increasing the shift amount of the rocker arm at high speed. . Further, the lift amount of only the intake valve or only the exhaust valve may be switched. Furthermore, the lift amount may be switched in three steps or more.

  While the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and can be implemented by appropriately modifying the above-described embodiment without departing from the spirit thereof.

1 is a side view showing an overall configuration of a motorcycle including a valve operating control device according to an embodiment of the present invention. It is sectional drawing which shows the structure of the engine shown in FIG. It is sectional drawing of the III-III line in FIG. It is a top view of the cam carrier shown in FIG. 2 and various components assembled | attached to it. It is sectional drawing of the VV line in FIG. It is sectional drawing of the VI-VI line in FIG. It is a disassembled perspective view of the cam carrier shown in FIG. 2, and the various components assembled | attached to it. It is a perspective view of the cam carrier shown in FIG. 7 and various components assembled | attached to it. It is a functional block diagram which shows the structure of ECU (valve control apparatus) shown in FIG. It is a figure which shows the switching determination map memorize | stored in the memory shown in FIG. It is a flowchart which shows the operation | movement by 1st Embodiment of the cam switching determination part shown in FIG. It is a flowchart which shows the subroutine of the cam switching determination process in FIG. FIG. 12 is a flowchart showing a subroutine of processing for initializing hysteresis immediately after switching in FIG. 11. It is a figure which shows the hysteresis selection map immediately after switching memorize | stored in the memory shown in FIG. 12 is a graph showing a relationship between an engine speed and a cam switching threshold value according to the operation shown in FIG. It is a flowchart which shows the operation | movement by 2nd Embodiment of the cam switching determination part shown in FIG. It is a flowchart which shows the subroutine of the process which initializes the holding time of the hysteresis immediately after switching in FIG. It is a figure which shows the hysteresis selection map immediately after switching memorize | stored in the memory shown in FIG. It is a graph which shows the relationship between the engine speed by the operation | movement shown in FIG. 16, and a cam switching threshold value. It is a graph which shows the relationship between the engine speed by the operation | movement of the conventional valve operating control apparatus, and a cam switching threshold value. (A) shows the effective tire diameter when the motorcycle stands upright when traveling straight, and (b) shows the effective tire diameter when the motorcycle is inclined during the turn. It is a graph which shows an engine speed when a motorcycle inclines at the time of a turn.

Explanation of symbols

133a to 133g Memory 39 Low speed cam 41 High speed cam 131 Engine speed calculation unit 132 Cam switching determination unit

Claims (5)

A valve operating control device for switching a lift amount of a valve to a first lift amount or a second lift amount larger than the first lift amount,
In the case where the lift amount of the valve is switched to the second lift amount, when the engine speed falls below a first threshold value, the lift amount of the valve is changed from the second lift amount to the second lift amount. When the valve lift is switched to the first lift amount and the valve lift amount is switched to the first lift amount, a second threshold value in which the engine speed is higher than the first threshold value. A lift amount switching means for switching the lift amount of the valve from the first lift amount to the second lift amount when
When the lift amount of the valve is switched from the second lift amount to the first lift amount by the lift amount switching means, the second threshold value is temporarily increased, and the lift amount switching means And a threshold value changing means for temporarily lowering the first threshold value when the lift amount of the valve is switched from the first lift amount to the second lift amount.
The threshold value changing unit is configured to change the first and second threshold values or the first and second threshold values when the lift amount of the valve is switched by the lift amount switching unit. A valve control apparatus that sets any one of the times during which the value change is held to a value corresponding to the amount of change per unit time of the engine speed . The valve operating control device according to claim 1,
The threshold value changing means sets the second threshold value from an initial value when the lift amount of the valve is switched from the second lift amount to the first lift amount by the lift amount switching means. After the engine speed is increased by a value corresponding to the amount of change per unit time , the second threshold value is gradually lowered to return to the initial value, and the lift amount of the valve is increased by the lift amount switching means. When the first lift amount is switched from the first lift amount to the second lift amount, the first threshold value is lowered from the initial value by a value corresponding to the change amount per unit time of the engine speed. , A valve operating control device that gradually increases the first threshold value to return to the initial value. The valve operating control device according to claim 1,
The threshold value changing means is a change amount per unit time of the engine speed when the lift amount of the valve is switched from the second lift amount to the first lift amount by the lift amount switching means. The second threshold value is increased by a predetermined amount during a time set corresponding to the above, and the lift amount of the valve is changed from the first lift amount to the second lift amount by the lift amount switching means. A valve control device that lowers the first threshold value by a predetermined amount during a time set corresponding to the amount of change per unit time of the engine speed when switched to.   An engine comprising the valve control apparatus according to claim 1. A motorcycle comprising the engine according to claim 4.

Images