JP4430611B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine capable of switching between a cylinder resting operation state in which some of a plurality of cylinders sharing an intake manifold are deactivated and an all cylinder operation state in which all cylinders are operated.

In a 2-cycle V-type 6-cylinder engine, when the number of cylinders that operate according to an increase in the accelerator opening is increased in order of 2 → 3 → 4 → 6, two cylinders are operated during 2-cylinder operation. Are ignited at equal intervals of 180 °, three cylinders are ignited at equal intervals of 120 ° during three-cylinder operation, and four cylinders are separated at 120 ° and 60 ° intervals during four-cylinder operation. Japanese Patent Application Laid-Open Publication No. 2004-228561 discloses that a mixture is ignited and six cylinders are ignited at equal intervals of 60 ° during six-cylinder operation.
JP-A-8-114133

  By the way, in the above-mentioned conventional one, one cylinder among the three cylinders of the one-side bank is deactivated during the four-cylinder operation, and therefore, the ignition sequence is changed to the deactivated cylinder → first activated cylinder → second activated cylinder at 120 ° intervals. The period from the operation of the second operation cylinder to the operation of the second operation cylinder is 120 °, but the period from the operation of the second operation cylinder to the operation of the first operation cylinder is doubled. It becomes 240 degrees. As a result, the intake air amount of the first operating cylinder becomes larger than the intake air amount of the second operating cylinder, and there is a problem that vibration and noise increase due to the difference in output torque between the first and second operating cylinders.

  The present invention has been made in view of the above-described circumstances, and provides an internal combustion engine capable of reducing the difference in intake air amount of an operating cylinder during idle cylinder operation and minimizing the generation of vibration and noise. For the purpose.

  In order to achieve the above object, according to the first aspect of the present invention, a cylinder resting operation state in which a part of a plurality of cylinders sharing an intake manifold is deactivated and an all cylinder operation state in which all cylinders are operated. In the internal combustion engine that can be switched between, the ignition sequence includes three cylinders in which the ignition sequence is continuous in the order of the idle cylinder, the first active cylinder, and the second active cylinder in the idle cylinder operation state. The engine valve is driven by the first valve operating cam in the all cylinder operating state, and is driven by the second valve operating cam in the idle cylinder operating state, and the difference between the intake air amounts of the first and second operating cylinders in the idle cylinder operating state. In order to reduce this, there is proposed an internal combustion engine characterized in that the profile of the second valve operating cam of the first operating cylinder is different from the profile of the second valve operating cam of the second operating cylinder.

  The intake valve 16 and the exhaust valve 19 of the embodiment correspond to the engine valve of the present invention, and the intake side first valve cam 33 and the exhaust side first valve cam 35 of the embodiment are the first valve valve of the present invention. Corresponding to the cam, the intake side second valve cam 33 'and the exhaust side second valve cam 35' of the embodiment correspond to the second valve cam of the present invention, and the # 3 cylinders C1 and # 4 of the embodiment. The cylinder C4 corresponds to the idle cylinder of the present invention, the # 1 cylinder C1 and the # 5 cylinder C5 of the embodiment correspond to the first operating cylinder of the present invention, and the # 2 cylinder C2 and the # 6 cylinder C6 of the embodiment correspond to the main cylinder. This corresponds to the second operating cylinder of the invention.

  According to the configuration of the first aspect, when the ignition order of the three cylinders in the idle cylinder operation state is the idle cylinder → the first active cylinder → the second active cylinder, the second active cylinder is operated after the first active cylinder is activated. Since the period from the operation of the second operation cylinder to the operation of the first operation cylinder is longer than the period until the cylinder is operated, the intake air amount of the first operation cylinder is the intake air of the second operation cylinder. The profile of the second valve drive cam that drives the engine valve of the first working cylinder and the profile of the second valve drive cam that drives the engine valve of the second working cylinder in the idle cylinder operation state. By making these differ, it is possible to reduce the difference between the intake air amounts of the first and second operating cylinders and to minimize the generation of vibration and noise.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 10 show a first embodiment of the present invention. FIG. 1 is a top view of a cylinder head of a first bank of a V-type six-cylinder internal combustion engine (a view taken along line 1-1 in FIG. 2). 2 is a sectional view taken along line 2-2 in FIG. 1, FIG. 3 is a sectional view taken along line 3-3 in FIG. 2, FIG. 4 is a sectional view taken along line 4-4 in FIG. 6 is a cross-sectional view taken along line 6-6 in FIG. 3, FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 3, and FIG. 8 is a schematic diagram showing the cylinder arrangement of the first and second banks of the V-type 6-cylinder internal combustion engine. FIGS. 9 and 9 are diagrams showing valve lift characteristics during full cylinder operation and idle cylinder operation, and FIG. 10 is a diagram showing intake air amounts of the first and second operating cylinders during idle cylinder operation.

  As shown in FIG. 8, the # 1 cylinder C1, the # 2 cylinder C2, and the # 3 cylinder C3 are provided in the first bank B1 of the V-type six cylinder internal combustion engine, and the # 4 cylinder C4 and # 5 cylinder are provided in the second bank B2. C5 and # 6 cylinder C6 are provided. Among the # 1 cylinder C1, # 2 cylinder C2 and # 3 cylinder C3 of the first bank B1, the # 3 cylinder C3 can be deactivated, and the # 1 cylinder C1 and the # 2 cylinder C2 can change valve lift and valve timing. It is. Of the # 4 cylinder C4, # 5 cylinder C5 and # 6 cylinder C6 of the second bank B2, the # 4 cylinder C4 can be deactivated, and the # 5 cylinder C5 and the # 6 cylinder C6 are changed in valve lift and valve timing. Is possible. The structure of the valve operating mechanism of the # 3 cylinder C3 and the # 4 cylinder C4 which can be stopped is the operation of the # 1 cylinder C1, the # 2 cylinder C2, the # 5 cylinder C5 and the # 6 cylinder C6 whose valve lift and valve timing can be changed. Since it is basically the same as the structure of the valve mechanism, and the profile of the valve cam is merely different, the structure of the valve mechanism of the # 3 cylinder C3 that can be stopped will be described as a representative example.

  As shown in FIGS. 1 to 7, an intake port 12 and an exhaust port 13 connected to the combustion chamber 11 are formed in the cylinder head 10, and the intake valve hole 14 is guided by the valve guide 15 so that the stem 16 a is slidable. The exhaust valve hole 17 is opened and closed by the umbrella portion 19b of the exhaust valve 19 slidably guided by the valve guide 18 through the stem 19a. The intake valve 16 and the exhaust valve 19 are urged in the valve closing direction by valve springs 61 and 62, respectively, and are controlled to open and close by a valve mechanism 21 driven by a camshaft 20 rotatably supported by the cylinder head 10. The

  A rocker shaft holder 22 is fastened to the cylinder head 10 by a plurality of bolts 23, and an intake side rocker shaft 24 and an exhaust side rocker shaft 25 are supported by the rocker shaft holder 22 along the cylinder arrangement direction.

  An intake-side drive rocker arm 26 and an intake-side free rocker arm 27 are swingably supported on the intake-side rocker shaft 24, and the intake-side drive rocker arm 26 abuts an adjustment screw 28 on the upper end of the stem 16 a of the intake valve 16. As a result, the intake valve 16 is always linked and connected. One intake side drive rocker arm 26 and one intake side free rocker arm 27 are provided for each of the pair of intake valves 16, 16, and the intake side drive rocker arm 26 drives the pair of intake valves 16, 16. Therefore, the tip is formed to be bifurcated.

  An exhaust-side drive rocker arm 29 and an exhaust-side free rocker arm 30 are swingably supported on the exhaust-side rocker shaft 25. The exhaust-side drive rocker arm 29 applies an adjustment screw 31 to the upper end of the stem 19a of the exhaust valve 19. By being in contact, the exhaust valve 19 is always linked and connected. One exhaust side drive rocker arm 29 and one exhaust side free rocker arm 30 are provided for each of the pair of exhaust valves 19, 19.

  The camshaft 20 is pivotally supported by an intake-side first valve cam 33 (see FIG. 5) that causes a roller 32 pivotally supported by the intake-side free rocker arm 27 to be in rolling contact with the exhaust-side free rocker arms 30 and 30. A pair of exhaust-side first valve cams 35, 35 (see FIG. 7) that are in rolling contact with the rollers 34, 34, respectively, and a raised portion 37 (FIG. 4) that is in sliding contact with the roller 36 provided on the intake-side drive rocker arm 26. And a pair of raised portions 39, 39 (see FIG. 6) that are in sliding contact with the rollers 38, 38 provided on the exhaust-side drive rocker arms 29, 29.

  The intake side first valve cam 33 is formed to have a cam profile for opening and closing the intake valve 16, and the exhaust side first valve cam 35 is formed to have a cam profile for opening and closing the exhaust valve 19. However, the raised portions 37 and 39 are formed so that the intake valve 16 and the exhaust valve 19 are substantially closed. Therefore, the intake valve 16 opens and closes when the intake side drive rocker arm 26 is connected to the intake side free rocker arm 27, but the connection of the intake side drive rocker arm 26 to the intake side free rocker arm 27 is released. In some cases, the valve is substantially closed. The exhaust valve 19 opens and closes when the exhaust side drive rocker arm 29 is connected to the exhaust side free rocker arm 30, but the connection of the exhaust side drive rocker arm 29 to the exhaust side free rocker arm 30 is released. In some cases, the valve is substantially closed.

  The intake-side drive rocker arm 26 and the intake-side free rocker arm 27 are provided with an intake-side switching mechanism 40 that switches connection and release of the intake-side drive rocker arm 26 to and from the intake-side free rocker arm 27 by hydraulic pressure.

  The intake side switching mechanism 40 has one end facing the first hydraulic chamber 41 formed in the intake side drive rocker arm 26 and the other end facing the second hydraulic chamber 42 formed in the intake side free rocker arm 27. And a connection pin 43 slidably fitted to the intake-side drive rocker arm 26 and the intake-side free rocker arm 27, and an intake-side free rocker arm 27 and the connection pin 43 housed in the second hydraulic chamber 42. And a return spring 44 provided therebetween.

  In the intake side switching mechanism 40, when hydraulic pressure is applied to the first hydraulic chamber 41, the connecting pin 43 moves to the second hydraulic chamber 42 side, and the intake side free rocker arm 27 and the intake side drive rocker arm 26 are connected. Is released. Conversely, when the hydraulic pressure acting on the first hydraulic chamber 41 is removed, the connecting pin 43 moves to the first hydraulic chamber 41 side by the elastic force of the return spring 44, and the intake-side free rocker arm 27 and the intake-side drive rocker arm 26. Are concatenated. In this way, the intake-side switching mechanism 40 switches the connection and release of the intake-side free rocker arm 27 to the intake-side drive rocker arm 26 by supplying the hydraulic pressure to the first hydraulic chamber 41, thereby operating the intake valve 16. Can be changed.

  A split member 45 that divides the intake side rocker shaft into two parts is fitted in the intake side rocker shaft 24, and the first hydraulic chamber 41 is provided in the intake side rocker shaft 24 by the split member 45. A first hydraulic oil passage 46 communicating with the second hydraulic fluid passage 47 and a second hydraulic oil passage 47 communicating with the second hydraulic chamber 42 are formed independently of each other.

  Further, the exhaust-side drive rocker arm 29 and the exhaust-side free rocker arm 30 that are adjacently arranged in pairs on the exhaust valve 19 side are connected to and disconnected from the exhaust-side free rocker arm 30. An exhaust side switching mechanism 48 that switches hydraulically is provided.

  The exhaust side switching mechanism 48 has one end facing the first hydraulic chamber 49 formed in the exhaust side drive rocker arm 29 and the other end of the second hydraulic chamber 50 formed in the exhaust side free rocker arm 30. A connection pin 51 slidably fitted to the exhaust side drive rocker arm 29 and the exhaust side free rocker arm 30 and a space between the exhaust side drive rocker arm 29 and the connection pin 51 accommodated in the first hydraulic chamber 49. And a return spring 52.

  In the exhaust side switching mechanism 48, when the hydraulic pressure acting on the second hydraulic chamber 50 is released, the connecting pin 51 moves to the second hydraulic chamber 50 side by the elastic force of the return spring 52, and the exhaust side free rocker arm 30 and The exhaust side drive rocker arm 29 is connected. Conversely, when hydraulic pressure is applied to the second hydraulic chamber 50, the connecting pin 51 moves to the first hydraulic chamber 49 side against the elastic force of the return spring 52, and the exhaust-side free rocker arm 30 and the exhaust-side drive rocker. The connection of the arm 29 is released. In this way, the exhaust-side switching mechanism 48 switches the connection and release of the exhaust-side free rocker arm 30 to the exhaust-side drive rocker arm 29 by supplying the hydraulic pressure to the second hydraulic chamber 50 to operate the exhaust valve 19. Can be changed.

  A split member 53 that divides the exhaust side rocker shaft 28 into two parts is fitted in the exhaust side rocker shaft 25, and the first hydraulic chamber is placed in the exhaust side rocker shaft 25 by the split member 53. A first hydraulic oil passage 54 leading to 49 and a second hydraulic oil passage 55 leading to the second hydraulic chamber 50 are formed independently of each other.

  The intake side free rocker arm 27 is biased to the intake side first valve cam 33 of the camshaft 20 in a state where the intake side switching mechanism 40 releases the connection of the intake side free rocker arm 27 to the intake side drive rocker arm 26. An intake side lost motion spring 56 is provided between the rocker shaft holder 22 and the intake side free rocker arm 27. Further, the exhaust side free rocker arm 30 is biased to the exhaust side first valve cam 35 of the camshaft 20 in a state where the exhaust side switching mechanism 48 releases the connection of the exhaust side free rocker arm 30 to the exhaust side drive rocker arm 29. An exhaust side lost motion spring 57 is provided between the rocker shaft holder 22 and the exhaust side free rocker arm 30.

  On the base end side of the intake-side free rocker arm 27, a roller 32 that contacts the intake-side first valve cam 33 and a spring contact portion 27b that contacts the intake-side lost motion spring 56 are provided, and an intake-side drive rocker arm 26 is provided with an adjusting screw 28 that contacts the upper end of the stem 16 a of the intake valve 16, and the intake side switching mechanism 40 has an intake side drive rocker arm 26 and an intake side free rocker arm rather than the intake side rocker shaft 24. 27 on the base end side. Similarly, on the base end side of the exhaust-side free rocker arm 30, a roller 34 that contacts the exhaust-side first valve cam 35 and a spring contact portion 30b that contacts the exhaust-side lost motion spring 57 are provided. An adjustment screw 31 that abuts the upper end of the stem 19a of the exhaust valve 19 is provided on the distal end side of the drive rocker arm 29, and the exhaust side switching mechanism 48 is connected to the exhaust side drive rocker arm 29 and the exhaust side from the exhaust side rocker shaft 25. It is arranged on the base end side of the free rocker arm 30.

  The structure of the valve mechanism 21 of the # 3 cylinder C3 that can be stopped has been described above, but the structure of the valve mechanism 21 of the other # 4 cylinder C4 that can be stopped is the same. The valve mechanism 21 of the # 1 cylinder C1, # 2 cylinder C2, # 5 cylinder C5 and # 6 cylinder C6 whose valve lift and valve timing can be changed is the operation of the # 3 cylinder C3 and # 4 cylinder C4 which can be stopped. Instead of the raised portions 37 and 39 of the valve mechanism 21, an intake side second valve cam 33 '(shown in a chain line in FIGS. 4 and 5) and an exhaust side second valve cam 35' (shown in a chain line in FIG. 7) are provided. The other structures are the same.

  Next, the operation of this embodiment will be described.

  As shown in FIG. 8, the firing order of # 1 cylinder C1 to # 6 cylinder C6 is as follows: # 1 cylinder C1 → # 4 cylinder C4 → # 2 cylinder C2 → # 5 cylinder C5 → # 3 cylinder C3 → # 6 cylinder C6 It is. All cylinders # 1 to C6 operate during full cylinder operation, but # 3 cylinder C3 in the first bank B1 and # 4 cylinder C4 in the second bank B2 deactivate during idle cylinder operation. The stop control of the # 3 cylinder C3 and the # 4 cylinder C4 is performed by the valve operating mechanism 21 described with reference to FIGS.

  The # 1 cylinder C1 to # 3 cylinder C3 of the first bank B1 share an intake manifold (not shown), and the firing order of the # 1 cylinder C1 to # 3 cylinder C3 is # 3 cylinder C3 (rest cylinder) → # 1 cylinder C1 (first operating cylinder) → # 2 cylinder C2 (second operating cylinder). The # 4 cylinder C4 to # 6 cylinder C6 of the second bank B2 share an intake manifold (not shown), and the ignition order of the # 4 cylinder C4 to # 6 cylinder C6 is # 4 cylinder C4 (rest cylinder). → # 5 cylinder C5 (first operating cylinder) → # 6 cylinder C6 (second operating cylinder).

  For example, when focusing on the # 4 cylinder C4 to # 6 cylinder C6 of the second bank B2, as shown in FIG. 10B as a conventional example, the first operating cylinder that operates after the # 4 cylinder C4, which is the idle cylinder, is used. An intake air amount of a certain # 5 cylinder C5 is larger than an intake air amount of a # 6 cylinder C6 that is a second operating cylinder that operates after the # 5 cylinder C5. As a result, there is a problem that the torque generated by the operation of the # 5 cylinder C5 during the idle cylinder operation becomes larger than the torque generated by the operation of the # 6 cylinder C6, and vibration and noise are generated due to the torque difference.

  As shown in FIG. 9A, in this embodiment, the valve lift of the intake valve 16 of the # 1 cylinder C1 to the cylinder # 6 of the cylinder # 1 is the same and the valve lift of the exhaust valve 22 is the same during all cylinder operation. . However, as shown in FIG. 9 (B), during the idle cylinder operation in which the # 3 cylinder C3 and the # 4 cylinder C4 which are the deactivated cylinders are deactivated, the intake air of the # 2 cylinder C2 and the # 6 cylinder C6 which are the second active cylinders. While the valve lifts of the valve 16 and the exhaust valve 22 are the same as in the all cylinder operation, the valve lifts of the intake valve 16 and the exhaust valve 22 of the # 1 cylinder C1 and the # 5 cylinder C5 which are the first operating cylinders are all. It becomes smaller than the time of cylinder operation. In the second operating cylinder, the profiles of the intake side first valve cam 33 and the exhaust side first valve cam 35 and the profiles of the intake side second valve cam 33 'and the exhaust side second valve cam 35' are shown. However, in the first working cylinder, the intake side second valve cam 33 'and the exhaust side first valve are compared with the profiles of the intake side first valve cam 33 and the exhaust side first valve cam 35. This is because the profile of the two-valve cam 35 'is set low.

  As described above, the intake air of the # 1 cylinder C1 and the # 5 cylinder C5, which are the first operating cylinders whose intake air amount tends to increase in order to operate next to the # 3 cylinder C3 and the # 4 cylinder C4 which are the idle cylinders. By reducing the valve lift of the valve 16 and the exhaust valve 22, as shown in FIG. 10A, the intake air amount of the # 1 cylinder C1 and the # 5 cylinder C5, which are the first operating cylinders, and the second operating cylinder This makes it possible to equalize the intake air amounts of the # 2 cylinder C2 and # 6 cylinder C6, and to suppress an increase in vibration and noise during the idle cylinder operation.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the first embodiment described above, the intake air amounts of the # 1 cylinder C1 and the # 5 cylinder C5, which are the first operating cylinders, are reduced by reducing the valve lifts of the intake valve 16 and the exhaust valve 22, In the second embodiment, the intake air amount is reduced by delaying the valve timing of the intake valve 16 of the # 1 cylinder C1 and the # 5 cylinder C5 which are the first operating cylinders.

  That is, during the idle cylinder operation, the first operation shown in FIG. 11 (A) is compared with the valve timing of the intake valves 16 of the # 2 cylinder C2 and # 6 cylinder C6, which are the second operation cylinders shown in FIG. 11 (B). The valve timings of the intake valves 16 of the # 1 cylinder C1 and # 5 cylinder C5, which are cylinders, are delayed. This delay in valve timing is achieved by shifting the phase of the intake side second valve cam 33 '. As a result, even after the intake stroke ends and the bottom dead center is exceeded, the intake valve 16 is kept open for a while, and the air once taken into the cylinder is pushed out from the intake valve 16 which has been opened to the intake passage. (See the hatched portion in FIG. 11A), the intake air amount of the # 1 cylinder C1 and the # 5 cylinder C5, which are the first operating cylinders, can be reduced.

  Thus, the second embodiment can achieve the same effects as the first embodiment described above.

  Although not included in the technical scope of the present invention, in an internal combustion engine in which an intake valve and an exhaust valve are driven by an electromagnetic actuator so that valve lift and valve timing can be arbitrarily set, individual cylinders can be operated during cylinder resting operation. Calculate the average value of the intake air amount from the detected value of the air flow meter, calculate the deviation between this average value and the average value of the intake air amount of all the operating cylinders, and calculate the valve lift and valve calculated based on this deviation The intake air amount of each operating cylinder may be made uniform by using the timing change amount.

  Although the embodiments of the present invention have been described above, various design changes can be made without departing from the scope of the present invention.

  For example, although the V-type 6-cylinder internal combustion engine is illustrated in the embodiment, the present invention is applied to an internal combustion engine of an arbitrary type that is connected to a common intake manifold and performs a rest-cylinder operation of a stop → operation → operation. Can do.

Top view of a cylinder head of one bank of a V-type 6-cylinder internal combustion engine (a view taken along line 1-1 in FIG. 2) 2-2 sectional view of FIG. 3-3 sectional view of FIG. Sectional view taken along line 4-4 in FIG. Sectional view along line 5-5 in FIG. 6-6 sectional view of FIG. Sectional view along line 7-7 in FIG. Schematic diagram showing the cylinder arrangement of the first and second banks of the V-type six-cylinder internal combustion engine Diagram showing valve lift characteristics during full cylinder operation and idle cylinder operation The figure which shows the intake air quantity of the 1st, 2nd working cylinder at the time of a cylinder resting operation The figure corresponding to the said FIG. 9 (B) based on 2nd Example of this invention.

Explanation of symbols

16 Intake valve (engine valve)
19 Exhaust valve (engine valve)
33 Intake side first valve cam (first valve cam)
35 Exhaust side first valve cam (first valve cam)
33 'Intake side second valve cam (second valve cam)
35 'Exhaust side second valve cam (second valve cam)
C1 # 1 cylinder (first operating cylinder)
C2 # 2 cylinder (second operating cylinder)
C3 # 3 cylinder (stop cylinder)
C4 # 4 cylinder (stop cylinder)
C5 # 5 cylinder (first operating cylinder)
C6 # 6 cylinder (second operating cylinder)

Claims (1)

In an internal combustion engine capable of switching between a cylinder resting operation state in which a part of a plurality of cylinders (C1 to C6) sharing an intake manifold is deactivated and an all cylinder operation state in which all cylinders (C1 to C6) are operated,
In the idle cylinder operation state, there are provided three cylinders whose ignition sequence is continuous in the order of idle cylinders (C3, C4), first active cylinders (C1, C5), and second active cylinders (C2, C6), The engine valves (16, 19) of the second operating cylinders (C1, C5; C2, C6) are driven by the first valve cams (33, 35) in the all-cylinder operation state, and the second operation is performed in the idle cylinder operation state. The first working cylinder is driven by a valve cam (33 ', 35') and is used to reduce the difference in intake air amount between the first and second working cylinders (C1, C5; C2, C6) in the cylinder resting state. The profile of the second valve cam (33 ', 35') of (C1, C5) is different from the profile of the second valve cam (33 ', 35') of the second working cylinder (C2, C6). An internal combustion engine characterized by the above.

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