JP2017008782A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of reducing noise in a cylinder deactivation operation of the internal combustion engine.SOLUTION: An internal combustion engine includes a plurality of connection pipes branched from an intake passage and respectively connected to a plurality of cylinders, and a control device for controlling opening/closing of an intake valve of a part of cylinders to be deactivated in a deactivation state in which a part of the cylinders is deactivated by stopping combustion in a part of the cylinders among the plurality of cylinders. The control device controls opening/closing of the intake valve of a part of the cylinders on the basis of a position of a piston of a part of the cylinders to be deactivated during an intake process of the cylinders in which the combustion is continued.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an internal combustion engine.

  2. Description of the Related Art Conventionally, as a technique for controlling an internal combustion engine mounted on a vehicle or the like, cylinder deactivation control is known that deactivates some of the cylinders by suspending combustion in some of the cylinders. . The cylinder deactivation control is a control that is executed when the required torque of the internal combustion engine is relatively small. During the cylinder deactivation operation, the intake valves and exhaust valves of some cylinders are maintained in a closed state, fuel injection into the cylinders is stopped, and output torque is obtained by the remaining cylinders. At this time, in order to obtain the same output torque as when all cylinders are operated by the remaining cylinders, the opening degree of the intake throttle valve is increased, so that the pumping loss is reduced and the fuel consumption characteristics are improved.

  Here, in an intake system of an internal combustion engine, pressure pulsation (hereinafter, this pulsation is also referred to as “intake pulsation”) is generated by intake of each cylinder. For example, when two cylinders of a four-cylinder engine are deactivated, the number of intakes during two revolutions of the crankshaft is halved, so the period of intake pulsation is also halved. As a result, the mode of vibration caused by the intake air pulsation of the engine changes from the secondary to the primary, and the low-frequency component of the intake sound becomes larger than that during the four-cylinder operation. In general, the cylinder deactivation control is executed in an operation region where the required torque of the internal combustion engine is small. Therefore, the low frequency component of the intake sound during the cylinder deactivation operation is easily felt as noise.

  On the other hand, there is an internal combustion engine having a silencer in the intake system. For example, Patent Document 1 discloses an internal combustion engine that can reduce intake noise during all-cylinder operation and cylinder deactivation operation without increasing the size of the resonator. The internal combustion engine includes a first resonator, and includes a first intake passage that communicates with a cylinder of one cylinder bank, a second intake passage that includes a second resonator and communicates with a cylinder of the other cylinder bank, a first intake passage, A bypass passage communicating with the second intake passage, and an open / close valve provided on the upstream side of the second resonator in the second intake passage. The on-off valve is opened during all cylinder operation and closed during cylinder deactivation operation. Thereby, at the time of cylinder deactivation operation, since the intake passage is configured to include two resonators, low-frequency noise can be reduced.

  Patent Document 2 discloses an intake noise reduction device for reducing noise during cylinder deactivation in an internal combustion engine having an independent intake system for each of a plurality of cylinder groups. The internal combustion engine includes a communication unit that communicates the upstream side of the throttle valve provided in the intake system of the cylinder group to be deactivated with the intake system of the cylinder group to be activated during the cylinder deactivation operation. In such an internal combustion engine, the air cleaner provided in the intake system of the cylinder for which the operation is suspended functions as a resonator for the operated cylinder, and noise can be reduced.

JP 2010-163945 A JP-A-8-3030312

  However, the internal combustion engines described in Patent Documents 1 and 2 are each an internal combustion engine provided with an intake throttle valve and a resonator or an air cleaner in each of two intake systems branched from an intake passage for taking in fresh air to each cylinder bank. In addition to being intended for an engine, a communication path connecting two intake systems is provided, which makes the configuration complicated.

  Further, in order to reduce low frequency sound, a large capacity or long silencer is required, and installation is often difficult due to the layout in the engine room of the vehicle. Therefore, it is desirable to be able to reduce low-frequency sound without newly adding a silencer or newly providing a communication path as described in Patent Documents 1 and 2.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an internal combustion engine capable of reducing noise during cylinder deactivation operation of the internal combustion engine.

  In order to solve the above problems, according to an aspect of the present invention, a plurality of connection pipes branched from an intake passage and connected to a plurality of cylinders, and combustion in some cylinders of the plurality of cylinders are performed. A control device that controls opening and closing of the intake valves of the some cylinders that are to be stopped in a resting state in which the some cylinders are being stopped by stopping the cylinder, wherein the control device continues the combustion An internal combustion engine is provided that controls the opening and closing of the intake valves of the some cylinders based on the positions of the pistons of the some cylinders that are stopped during the intake process.

  When the pistons of the some cylinders are located at positions where the predetermined frequency component of the intake noise can be reduced when the intake valves of the some cylinders to be stopped are opened, the control device The intake valves of some cylinders may be opened.

  The control device may open the intake valves of the some cylinders after the pistons of the some cylinders to be stopped have been lowered.

  The cross-sectional area and length of the connection pipe connected to the some cylinders to be stopped and the cylinder volume of the some cylinders when the intake valves of the some cylinders are opened The predetermined frequency component may be set to a value that can be reduced.

  The intake passage is provided with at least one silencer for reducing a predetermined frequency component of the intake sound, and in the resting state, the control device controls the part of the part during the intake process of the cylinder that continues combustion. The predetermined frequency component of the intake sound that is reduced by opening the intake valve of the cylinder may be different from the frequency component that is reduced by the silencer.

  The control device pauses some of the plurality of cylinders, and controls opening and closing of the intake valves of the some of the plurality of cylinders to be deactivated, thereby providing a plurality of predetermined intake noise sounds. The frequency component may be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the noise at the time of cylinder deactivation operation of an internal combustion engine can be reduced.

1 is a schematic diagram showing a schematic configuration of an internal combustion engine according to an embodiment of the present invention. It is a schematic diagram which shows the structural example of the intake system of an internal combustion engine. It is explanatory drawing which shows the intake pulsation which generate | occur | produces in the intake system of an internal combustion engine. It is explanatory drawing which shows the noise of an internal combustion engine. It is a flowchart which shows an example of the flow of the process which the control apparatus of an internal combustion engine performs. It is explanatory drawing which shows the silence function of a deactivation cylinder and a connecting pipe. It is explanatory drawing for demonstrating the opening / closing timing of the intake valve of a dormant cylinder at the time of a cylinder deactivation operation. It is explanatory drawing which shows the resonance frequency of the silence function of a dormant cylinder and a connecting pipe, and each silencer.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol. In addition, components having substantially the same functional configuration may be distinguished by adding different alphabets to the end of the same symbol.

<1. Configuration of Internal Combustion Engine>
(1-1. Overall configuration)
First, an example of the overall configuration of the internal combustion engine 100 according to the present embodiment will be described. FIG. 1 is a schematic diagram schematically showing a configuration example of the internal combustion engine 100. FIG. 1 is an explanatory diagram showing a configuration of a horizontally opposed internal combustion engine 100. In the internal combustion engine 100 shown in FIG. 1, the cylinders # 1 and # 2 are located on the front side of the vehicle.

  The internal combustion engine 100 includes a cylinder block 101a, a cylinder head 101b, a piston 104, a connecting rod 106, a spark plug 108, an intake valve 110a, an exhaust valve 110b, a cam mechanism 111, a crankshaft 115, and a control device 140. The cylinder block 101a is provided with a plurality of cylinders # 1, # 2, # 3, and # 4. In the example of FIG. 1, four cylinders # 1, # 2, # 3, and # 4 are provided in the cylinder block 101a. Of these, two cylinders # 1 and # 3 constitute a cylinder group in the right bank, and the remaining two cylinders # 2 and # 4 constitute a cylinder group in the left bank.

  The cylinder head 101b closes the ends opposite to the crankshaft 115 of the axial ends of the cylinders # 1, # 3 (# 2, # 4) in each of the right bank and the left bank. Provided. In each cylinder # 1, # 2, # 3, and # 4, a piston 104 is held so as to be able to move forward and backward. A combustion chamber C is defined by the cylinder head 101b and the crown surface of the piston 104 at the top dead center. The piston 104 performs a linear reciprocating motion by the combustion of fuel in the combustion chamber C. The linear reciprocating motion is transmitted as a rotational motion to the crankshaft 115 via the connecting rod 106.

  The internal combustion engine 100 is connected to an intake system 200 and an exhaust system (not shown). The intake system 200 supplies intake air to the cylinders # 1, # 2, # 3, and # 4. The intake system 200 includes an intake passage 202 provided with an intake throttle valve 210, a collector portion 204 connected to the intake passage 202, and branches from the collector portion 204 to each cylinder # 1, # 2, # 3, # 4. And a plurality of connecting pipes 206a, 206b, 206c, and 206d. The exhaust system discharges combustion gas from each cylinder # 1, # 2, # 3, # 4. The cylinder head 101b is provided with an intake valve 110a and an exhaust valve 110b for each cylinder # 1, # 2, # 3, and # 4.

  The intake valve 110a opens and closes an intake port between the intake system 200 and each combustion chamber C. In the intake stroke, intake valve 110a is opened, and intake air is taken into each combustion chamber C through the intake port. The exhaust valve 110b opens and closes an exhaust port between the exhaust system and each combustion chamber C. In the exhaust stroke, the exhaust valve 110b is opened so that the combustion gas is discharged from each combustion chamber C via the exhaust port. The opening and closing operations of the intake valve 110a and the exhaust valve 110b are realized by the cam mechanism 111.

  The cam mechanism 111 includes a camshaft 112, a four-cylinder operation cam 114 fixed to the camshaft 112, and a cylinder deactivation operation cam 130. The camshaft 112 is connected to a crankshaft 115 of the internal combustion engine via a gear (not shown), and rotates as the crankshaft 115 rotates. The intake valve 110a and the exhaust valve 110b include a return spring (not shown). As the camshaft 112 rotates, the four-cylinder operation cam 114 and the cylinder deactivation operation cam 130 rotate, and the cam peaks of the four-cylinder operation cam 114 or the cylinder deactivation operation cam 130 directly or indirectly. The intake valve 110a and the exhaust valve 110b are opened by pushing the 110a and the exhaust valve 110b.

  In the internal combustion engine 100 shown in FIG. 1, the rocker arm 30 is provided between the four-cylinder operation cam 114 or the cylinder deactivation operation cam 130 and the intake valve 110a and the exhaust valve 110b. The intake valve 110 a and the exhaust valve 110 b are pushed by the four-cylinder operation cam 114 or the cylinder deactivation operation cam 130 via the rocker arm 30. Further, when the intake valve 110a and the exhaust valve 110b are released from the pushing of the intake valve 110a and the exhaust valve 110b by the four-cylinder operation cam 114 or the cylinder deactivation operation cam 130, they are returned to their original positions by the return spring. .

  The cam mechanism 111 according to this embodiment is provided with a cylinder deactivation operation cam 130 having an outer peripheral shape different from that of the four-cylinder operation cam 114 at positions corresponding to the cylinders # 1 and # 2. The cylinder deactivation operation cam 130 performs an opening / closing operation different from the opening / closing operation by the 4-cylinder operation cam 114 during the cylinder deactivation operation in which the combustion in the cylinders # 1 and # 2 is stopped. And the exhaust valve 110b is provided for performing. Cams that push in the intake valves 110a and exhaust valves 110b of the cylinders # 1 and # 2 via the rocker arm 30 are switched by the control device 140 to either the four-cylinder operation cam 114 or the cylinder deactivation operation cam 130. . During the four-cylinder operation, the cams that push in the intake valves 110a and the exhaust valves 110b of the cylinders # 1 and # 2 via the rocker arm 30 are switched to the four-cylinder operation cam 114. On the other hand, during cylinder deactivation operation, the cams that push in the intake valves 110a and exhaust valves 110b of the cylinders # 1 and # 2 via the rocker arm 30 are switched to the cylinder deactivation operation cams 130.

  For example, when the control device 140 gives an operation instruction to a drive device (not shown) provided in the cam mechanism 111, the drive device follows the operation instructions, and the 4-cylinder operation cam 114 and cylinders corresponding to the cylinders # 1 and # 2 The cam 130 for pause operation is moved in the axial direction of the camshaft 112. As a result, the cams that push in the intake valves 110a and the exhaust valves 110b of the cylinders # 1 and # 2 via the rocker arm 30 are switched.

  The number of intake valves 110a and exhaust valves 110b provided in each cylinder # 1, # 2, # 3, and # 4 can be set as appropriate. In this embodiment, two intake valves 110a and two exhaust valves 110b are provided for each of the cylinders # 1, # 2, # 3, and # 4, and each of the intake valves 110a and the exhaust valves 110b is an intake port or an exhaust. Open and close the port. In FIG. 1, each cylinder # 1, # 2, # 3, # 4 shows a set of intake valves 110a.

  Each cylinder # 1, # 2, # 3, and # 4 is provided with a fuel injection valve (not shown) so as to face the combustion chamber C. The fuel injection valve is fixed to the wall surface of the cylinder head 101b, for example. The fuel injection valve is driven and controlled by the control device 140 and injects fuel into the combustion chamber C. As a result, an air-fuel mixture of intake air and fuel is formed in the combustion chamber C. Further, during the cylinder deactivation operation, the fuel injection into the cylinders # 1 and # 2 is stopped by the control device 140, whereby the combustion in the cylinders # 1 and # 2 is stopped. The fuel injection valve is not limited to a type that directly injects fuel into the combustion chamber C. A fuel injection valve may be provided upstream of the intake port, and a previously formed air-fuel mixture may be introduced into the combustion chamber C from the intake port.

  A spark plug 108 is provided in the cylinder head 101b so as to face the combustion chamber C of each cylinder # 1, # 2, # 3, and # 4. The spark plug 108 is driven and controlled by the control device 140 and ignites the air-fuel mixture formed in each combustion chamber C. As a result, combustion occurs in the combustion chamber C, the piston 104 is pushed down, and the crankshaft 115 rotates. In this specification, the rising of the piston 104 means that the piston 104 moves to the combustion chamber C side, and the lowering of the piston 104 means that the piston 104 moves to the crankshaft 115 side.

  The crankshaft 115 includes a crankpin 116, a crank journal 118, and a crank arm 120 connected thereto. The crankpin 116 is connected to the connecting rod 106. The crank arm 120 is rotated by the linear reciprocation of the piston 104, and the crank journal 118 is rotated by the rotation of the crank arm 120. The crankshaft 115 is connected to a drive transmission device (not shown), and the output torque of the internal combustion engine 100 is transmitted to the drive transmission device.

  The control device 140 includes a CPU (Central Processing Unit) that is an arithmetic processing unit, a ROM (Read Only Memory) that stores programs used by the CPU, operation parameters, and the like, a program used in the execution of the CPU, and changes as appropriate in its execution A RAM (Random Access Memory) that temporarily stores parameters and the like, and a data storage device such as an HDD (Hard Disk Drive) device that stores data and the like.

  The control device 140 controls the operation of each device constituting the internal combustion engine 100. Specifically, the control device 140 issues an operation instruction to each actuator to be controlled using an electrical signal. More specifically, the control device 140 switches the cam that pushes the intake valve 110a and the exhaust valve 110b of the cylinders # 1 and # 2 through the rocker arm 30 to the cylinder deactivation operation cam 130 during the cylinder deactivation operation. Thus, the opening and closing of the intake valves 110a and the exhaust valves 110b of the cylinders # 1 and # 2 are controlled.

  The technical scope of the present invention is an example in which the control device 140 controls the opening / closing of the intake valves 110a and the exhaust valves 110b of the cylinders # 1 and # 2 using the cylinder deactivation operation cam 130 during the cylinder deactivation operation. It is not limited to. For example, the control device 140 may control opening and closing of the intake valves 110a and the exhaust valves 110b of the cylinders # 1 and # 2 using an electric actuator (not shown) during the cylinder deactivation operation. In the internal combustion engine 100 according to the present embodiment, the noise during the cylinder deactivation operation of the internal combustion engine 100 is reduced by controlling the opening and closing of the intake valves 110a and the exhaust valves 110b of the deactivation cylinders # 1 and # 2 during the cylinder deactivation operation. It becomes possible to make it. Details of control of opening / closing of the intake valves 110a and exhaust valves 110b of the cylinders # 1 and # 2 by the control device 140 during such cylinder deactivation operation will be described later.

  Further, the control device 140 controls driving of the fuel injection valve, the spark plug 108 and the intake throttle valve 210. The control device 140 may communicate with a sensor (not shown) provided in the internal combustion engine 100 or another control device using CAN (Controller Area Network) communication.

(1-2. Configuration of intake system)
FIG. 2 is a schematic diagram showing the intake system 200 of the internal combustion engine 100. FIG. 2 shows the intake system 200 of one cylinder # 1.

  The intake system 200 includes an intake passage 202, a collector unit 204, and a connecting pipe 206a. The intake passage 202 includes an air cleaner 208, an intake throttle valve 210, a side branch type silencer 212, and a Helmholtz type silencer 214. Note that connecting pipes 206b, 206c, and 206d connected to the other cylinders # 2, # 3, and # 4 are connected to the collector unit 204. The intake system 200 guides fresh air taken from the intake opening 202a to the cylinder # 1. An exhaust system 250 is connected to the cylinder # 1.

  The intake throttle valve 210 is controlled by the control device 140 shown in FIG. 1 and adjusts the flow rate of fresh air passing through the intake passage 202. The intake throttle valve 210 is provided in the intake passage 202, and the opening degree of the intake throttle valve 210 changes as the intake throttle valve 210 rotates by an electric motor or the like. Thereby, the passage area of the intake passage 202 changes, and the flow rate of fresh air is adjusted. The opening degree of the intake throttle valve 210 is determined based on the required torque and the rotational speed of the internal combustion engine 100 with reference to a previously created opening degree map.

  Further, the opening degree of the intake throttle valve 210 is different between the four-cylinder operation and the cylinder deactivation operation. The opening degree of the intake throttle valve 210 during the cylinder deactivation operation is made larger than the opening degree of the intake throttle valve 210 during the four-cylinder operation in order to output the same torque as the torque during the four-cylinder operation from the internal combustion engine 100. . As a result, during cylinder deactivation, the amount of intake charge per cylinder increases, and the torque generated per cylinder increases.

  The air cleaner 208 collects foreign substances contained in the introduced fresh air. An air flow meter (not shown) for measuring the flow rate of fresh air is provided on the downstream side of the air cleaner 208. Further, an EGR (Exhaust Gas Recirculation) passage for returning a part of the exhaust to the intake system 200 may be connected to the intake passage 202 upstream of the intake throttle valve 210. In this case, an EGR valve is provided in the middle of the EGR passage, and the flow rate of EGR gas recirculated from the exhaust system 250 to the intake system 200 is adjusted.

  The collector unit 204 has a function of temporarily storing intake air and uniformly distributing the intake air to the cylinders # 1, # 2, # 3, and # 4. The connecting pipe 206a branches from the collector unit 204 and is connected to the cylinder # 1, and guides intake air in the collector unit 204 to the cylinder # 1. An intake port 220 is interposed between the connecting pipe 206a and the cylinder # 1, and the intake port 220 is opened and closed by the intake valve 110a. By opening the intake valve 110a while the piston 104 of the cylinder # 1 descends, intake air is sucked into the cylinder # 1.

  The side branch-type silencer 212 and the Helmholtz-type silencer 214 provided in the intake passage 202 reduce intake noise of a predetermined frequency. The side branch type silencer 212 is a tubular member whose open end is connected to the intake passage 202 and whose other end is closed, and the length is set according to the frequency component to be reduced. The side branch type silencer 212 reduces the frequency component by causing a specific frequency component of the sound generated in the intake passage 202 to resonate in the side branch type silencer 212. The side-branch silencer 212 is identified by the fact that when a specific frequency component enters the side-branch silencer 212, the air vibrates vigorously and the sound energy is lost due to friction loss with the side wall. Reduce frequency sound. The relationship between the length Ls of the side branch silencer 212 and the resonance frequency fn can be expressed by the following formula (1).

ｆｎ：共鳴周波数
Ｌｓ：消音器の長さ
ｎ：次数（ｎ＝１，２，・・・）
Ｃ：音速

fn: resonance frequency Ls: silencer length n: order (n = 1, 2,...)
C: Speed of sound

  Further, the Helmholtz type silencer 214 is a resonator in which an opening end of a tubular portion is connected to the intake passage 202 and an expansion chamber (resonance chamber) is provided on the other end side, and the tubular portion according to a frequency component to be reduced. The length, the cross-sectional area, or the volume of the expansion chamber is set. The Helmholtz silencer 214 is configured to vibrate the air in the tubular portion vigorously when a specific frequency component of the sound generated in the intake passage 202 enters the Helmholtz silencer 214. The sound energy is lost due to frictional loss with the side wall, thereby reducing the sound of a specific frequency. The relationship between the length Lh of the tubular portion in the Helmholtz silencer 214 and the resonance frequency fn can be expressed by the following formula (2).

ｆｎ：共鳴周波数
Ｌｈ：管状部の長さ
Ｓｈ：管状部の断面積
Ｖ：拡張室の容積
ｎ：次数（ｎ＝１，２，・・・）
Ｃ：音速

fn: resonance frequency Lh: length of tubular portion Sh: sectional area of tubular portion V: volume of expansion chamber n: order (n = 1, 2,...)
C: Speed of sound

  The side branch type silencer 212 and the Helmholtz type silencer 214 attenuate pulsations of different frequency components. Further, a plurality of side branch type silencers 212 and Helmholtz type silencers 214 may be provided in accordance with the frequency components to be attenuated. However, the lower the frequency of the sound to be silenced by the side branch silencer 212 and the Helmholtz silencer 214, the longer or larger capacity the silencer must be. is there.

<2. Intake noise>
Next, intake noise generated in the intake system 200 will be described. FIG. 3 is a diagram showing a standing wave when the intake system 200 is viewed as a pipe line with one end closed and one end open.

  The upper diagram of FIG. 3 shows a standing wave when the vibration mode is second order. When the order is 2, the intake opening 202a serving as the opening end is a node, and the end on the cylinder # 1 (# 2, # 3, # 4) side where intake is performed is abdomen. A standing wave with a wavelength of / 3 is generated. On the other hand, the lower diagram in FIG. 3 shows a standing wave when the vibration mode is the first order. When the order is 1, the intake opening 202a serving as the opening end is a node, and the end on the cylinder # 1 (# 2, # 3, # 4) side where intake is performed is abdomen. A standing wave having a double wavelength, that is, a standing wave having a frequency lower than that of the second order is generated.

  Here, the basic order of the internal combustion engine 100 varies depending on the number of cylinders to be operated (intake timing). That is, the frequency of the intake pulsation generated in the intake system 200 by the vibration force generated by the intake air varies depending on the number of cylinders to be operated. Specifically, the basic order at the time of four-cylinder operation is secondary, whereas the basic order at the time of cylinder deactivation (two-cylinder operation) is primary, and the frequency of intake pulsation during cylinder deactivation is 1/2 of the frequency during 4-cylinder operation. For example, when the rotational speed of the internal combustion engine 100 is 1800 rpm, the frequencies when the basic order is the second order and the first order are 60 Hz and 30 Hz, respectively.

  Thus, the frequency of the intake pulsation during the four-cylinder operation of the internal combustion engine 100 is dominant when the basic order is second order, and the frequency of the intake pulsation during the cylinder deactivation operation is the first order of the basic order. In this case, the frequency becomes dominant. Therefore, when the intake system 200 is designed with the basic idea of reducing intake noise during four-cylinder operation, the sound in the frequency range when the basic order is secondary is reduced, while the basic order is primary. In this case, the sensitivity to the sound in the frequency range increases, and the intake noise in the low frequency range increases.

  FIG. 4 is a conceptual diagram showing the intensity of noise generated from the internal combustion engine 100 during four-cylinder operation and cylinder deactivation operation (two-cylinder operation). When the internal combustion engine 100 is switched from the four-cylinder operation to the two-cylinder operation, the low frequency component due to the intake pulsation increases, so the intensity of the low frequency component of the noise generated from the internal combustion engine 100 becomes relatively large. In addition, in order to attenuate the low frequency component of the intake sound generated during the two-cylinder operation by the side branch type silencer or the Helmholtz type silencer externally attached to the intake passage 202, it is necessary to use a long or large capacity silencer. Therefore, it is difficult to realize in the engine room layout.

<3. Silencer function of idle cylinder and connecting pipe>
The control device 140 of the internal combustion engine 100 according to the present embodiment controls opening and closing of the intake valve 110a and the exhaust valve 110b of the deactivated cylinders # 1 and # 2 during the cylinder deactivated operation. Specifically, as described above, the control device 140 sets the cam for pushing the intake valve 110a and the exhaust valve 110b of the cylinders # 1 and # 2 through the rocker arm 30 during the cylinder deactivation operation. By switching to 130, the opening and closing of the intake valves 110a and exhaust valves 110b of the cylinders # 1 and # 2 are controlled. Hereinafter, the flow of processing performed by the control device 140 of the internal combustion engine 100 will be described.

  FIG. 5 is a flowchart showing an example of the flow of processing performed by the control device 140 of the internal combustion engine 100. As shown in FIG. 5, the control device 140 determines whether or not it is during cylinder deactivation operation (step S502). When it is determined that the cylinder is deactivated (step S502 / YES), the control device 140 causes the cams for pushing the intake valves 110a and exhaust valves 110b of the cylinders # 1 and # 2 through the rocker arm 30 to perform the cylinder deactivated operation. The operation cam 130 is switched to (step S504). On the other hand, when it is determined that it is not during the cylinder deactivation operation (step S502 / NO), the control device 140 sets 4 cams for pushing the intake valves 110a and exhaust valves 110b of the cylinders # 1 and # 2 through the rocker arm 30. The operation is switched to the cylinder operation cam 114 (step S506). After the process of step S504 or step S506 is performed, the process returns to the process of step S502, and it is determined whether or not it is a cylinder deactivation operation.

  Subsequently, the control of the opening / closing of the intake valves 110a and the exhaust valves 110b of the cylinders # 1 and # 2 during the cylinder deactivation operation by the control device 140 will be described in more detail. During cylinder deactivation operation, the control device 140 always closes the exhaust valves 110b of the deactivation cylinders # 1 and # 2. On the other hand, during the cylinder deactivation operation, the control device 140 opens or closes the intake valves 110a of the deactivation cylinders # 1 and # 2 with a small valve opening compared to the valve opening during the four-cylinder operation. Let The intake valves 110a of the deactivated cylinders # 1 and # 2 during the cylinder deactivation operation are opened to reduce intake noise during the cylinder deactivation operation. The small amount of valve opening is set so as to reduce a pumping loss that may occur due to the valve opening.

  Specifically, during the cylinder deactivation operation, the control device 140 performs the intake valve 110a of the deactivated cylinder # 1 based on the position of the piston 104 of the deactivated cylinder # 1 during the intake process of the cylinder # 3 that continues combustion. Controls the opening and closing of. More specifically, when the intake valve 110a of the deactivated cylinder # 1 is opened, the control device 140 is positioned when the piston 104 of the deactivated cylinder # 1 is located at a position where a predetermined frequency component of the intake sound can be reduced. Then, the intake valve 110a of the idle cylinder # 1 is opened.

  FIG. 6 is a view for explaining the silencing function of the idle cylinder # 1 and the connection pipe 206a connected thereto in the internal combustion engine 100 according to the present embodiment. As described above, the connecting pipes 206a, 206b, 206c, and 206d connected to the cylinders # 1, # 2, # 3, and # 4 are branched from the collector unit 204. The collector portion 204 is located near the end point with respect to the entire length of the intake system 200 with the intake opening 202a as a base point. That is, the collector unit 204 is located at a position close to the antinode of the intake pulsation that occurs during the cylinder deactivation operation.

  In a state where the intake valve 110a of the idle cylinder # 1 is opened in the intake process of the cylinder # 3 that continues combustion during the cylinder idle operation, the connection pipe 206a and the idle cylinder # 1 connected to the idle cylinder # 1 are Helmholtz. Can function as a mold silencer. In particular, the connection pipe 206a and the idle cylinder # 1 can be regarded as a silencer provided at a position close to the antinode of the intake pulsation that occurs during the cylinder idle operation. Focusing on this point, in the internal combustion engine 100 according to the present embodiment, the cross-sectional area S and length L of the connection pipe 206a connected to the idle cylinder # 1 and the intake valve 110a of the idle cylinder # 1 are opened. The cylinder volume V of the idle cylinder # 1 at that time is set to a value that can reduce the component of the predetermined frequency for which the intake noise is desired to be reduced.

  Here, the cylinder volume V of the deactivated cylinder # 1 is treated as a value depending on the position of the piston 104 of the deactivated cylinder # 1 when the intake valve 110a of the deactivated cylinder # 1 is opened. For example, when the piston 104 of the idle cylinder # 1 is located at a position where the cylinder volume V of the idle cylinder # 1 becomes a set value, the control device 140 opens the intake valve 110a of the idle cylinder # 1. Let As a result, it is possible to reduce a component of a predetermined frequency for which intake noise is desired to be reduced.

  Since the connecting pipe 206a can function as a Helmholtz silencer, the cross-sectional area S and length L of the connecting pipe 206a shown in FIG. 6 and the idle cylinder when the intake valve 110a of the idle cylinder # 1 is opened are shown. The cylinder volume V of # 1 can be set by the above equation (2). Since the connection pipe 206a is originally longer than the tubular portion of the Helmholtz type silencer 214 externally attached to the intake passage 202, it can be a silencer having a relatively long length Lh. That is, the low frequency component of the intake noise generated during the cylinder deactivation operation can be reduced by the silencing function of the connection pipe 206a and the deactivation cylinder # 1.

  Further, the number of external silencers installed in the intake passage 202 can be obtained by using the connection pipe 206a connected to the idle cylinder # 1 and the idle cylinder # 1 as silencers that can reduce the specific frequency component of the intake noise. Can be reduced. Also by this, the internal combustion engine 100 according to the present embodiment is advantageous in terms of the layout of the internal combustion engine 100 in the engine compartment.

  FIG. 7 is an explanatory diagram for explaining the opening / closing timing of the intake valve 110a of the deactivated cylinder # 1 during the cylinder deactivated operation. FIG. 7 shows the relationship between the positions of the pistons 104 of the deactivated cylinder # 1 and the cylinder # 3 that continues combustion during the cylinder deactivated operation. In FIG. 7, the position of the piston 104 of the deactivated cylinder # 1 is indicated by a broken line, and the position of the piston 104 of the cylinder # 3 that continues combustion is indicated by a solid line. The value indicating the position of the piston 104 in FIG. 7 is a value in which the upward direction of the piston 104 is positive.

  As shown in FIG. 7, during the cylinder deactivation operation, the compression process, the expansion process, the exhaust process, and the intake process are repeated in order in cylinder # 3 that continues combustion. For example, when the piston 104 of the deactivated cylinder # 1 is located at a position between H1 and H2 shown in FIG. 7 during the intake process of the cylinder # 3 that continues to burn, the control device 140 controls the deactivated cylinder # 1. The intake valve 110a is opened. That is, the control device 140 opens the intake valve 110a of the idle cylinder # 1 between the crank angle CA1 and the crank angle CA2 shown in FIG. Here, when the intake valve 110a of the idle cylinder # 1 is opened when the piston 104 is located at a position between H1 and H2, the connection pipe 206a connected to the idle cylinder # 1 and H1 and H2 The position is set such that a predetermined frequency component for which intake noise is desired to be reduced can be reduced by the silencing function of the idle cylinder # 1.

  Further, the control device 140 may open the intake valve 110a of the deactivated cylinder # 1 after the piston 104 of the deactivated cylinder # 1 has finished descending. For example, the control device 140 opens the intake valve 110a of the deactivated cylinder # 1 after the crank angle CA1 shown in FIG. 7 in which the operation of the piston 104 of the deactivated cylinder # 1 changes from the descending operation to the ascending operation. Accordingly, it is possible to reduce the internal pressure of the deactivated cylinder # 1 when the intake valve 110a of the deactivated cylinder # 1 is opened during the cylinder deactivated operation. Therefore, the backflow of the intake air toward the intake system 200 due to the opening of the intake valve 110a of the deactivated cylinder # 1 during the cylinder deactivation operation can be suppressed. Therefore, noise due to the backflow of the intake air toward the intake system 200 can be suppressed.

  During the cylinder deactivation operation, a predetermined frequency component of the intake noise that is reduced by opening the intake valve 110a of the deactivated cylinder # 1 by the control device 140 during the intake process of the cylinder # 3 that continues combustion, and the intake It is preferable that the frequency component is reduced by the side branch silencer 212 and the Helmholtz silencer 214 attached to the passage 202. As a result, the side branch type silencer 212 and the Helmholtz type silencer 214 that are externally attached to the intake passage 202 have a function of reducing noise generated during four-cylinder operation, and at the time of cylinder deactivation operation, Low frequency noise can be reduced by the mute function of the connected connecting pipe 206a and the idle cylinder # 1.

  FIG. 8 shows the frequency components reduced by the side branch silencer 212 and the Helmholtz silencer 214 attached to the intake passage 202, and the silence function of the connection pipe 206a connected to the idle cylinder # 1 and the idle cylinder # 1. It is explanatory drawing which shows the frequency component reduced. In the example shown in FIG. 8, the side branch type silencer 212 and the Helmholtz type silencer 214 attached to the intake passage 202 reduce sound in the middle frequency range (for example, 400 to 1000 Hz) during four-cylinder operation. On the other hand, the noise in the low-frequency region (for example, 200 to 350 Hz) that is less likely to be noticed during the four-cylinder operation is reduced by the mute function of the connection pipe 206a connected to the idle cylinder # 1 and the idle cylinder # 1. .

  In the above description, the example in which the intake valve 110a of the cylinder # 1 is opened during the intake process of the cylinder # 3 during the cylinder deactivation operation is described, but during the intake process of the cylinder # 4 during the cylinder deactivation operation. Even if the intake valve 110a of the cylinder # 1 is opened, the same effect can be obtained. In the above description, the connection pipe 206a connected to the idle cylinder # 1 and the function as the Helmholtz silencer of the idle cylinder # 1 have been described. However, the connection pipe 206b and the idle cylinder # 2 connected to the idle cylinder # 2. 2 can also function as a Helmholtz-type silencer. Further, during the cylinder deactivation operation, the intake valves 110a of both the deactivated cylinder # 1 and the deactivated cylinder # 2 may be opened during the intake process of either the cylinder # 3 or the cylinder # 4.

  The control device 140 may reduce a plurality of predetermined frequency components of the intake sound by controlling the opening and closing of the intake valves 110a of the deactivated cylinders # 1 and # 2. Specifically, the control device 140 determines the frequency of sound to be reduced by the silencing function of the connection pipe 206a and the idle cylinder # 1 connected to the cylinder # 1, and the connection pipe 206b and the idle cylinder # connected to the cylinder # 2. The opening and closing of the intake valves 110a of the idle cylinders # 1 and # 2 may be controlled so that the frequency of the sound to be reduced by the mute function 2 is different. That is, the cross-sectional area S and length L of the connection pipe 206a, the cylinder volume V of the idle cylinder # 1 when the intake valve 110a of the idle cylinder # 1 is opened, and the cross-sectional area S and length of the connection pipe 206b. L and the cylinder volume V of the deactivated cylinder # 2 when the intake valve 110a of the deactivated cylinder # 2 is opened may be set according to different frequencies from which it is desired to reduce the intake noise. Thereby, a plurality of predetermined frequency components can be reduced among the low frequency components of the intake sound generated during the cylinder deactivation operation.

  In this manner, during the intake process of cylinders # 3 and # 4 that continue combustion, the intake valve 110a of the idle cylinder # 1 (# 2) is determined based on the position of the piston of the idle cylinder # 1 (# 2). By controlling the opening and closing, it is possible to reduce the low-frequency component sound generated during the cylinder deactivation operation without increasing the number of silencers attached to the intake passage 202.

<4. Effect>
As described above, the internal combustion engine 100 according to the present embodiment is positioned at the position of the piston of the deactivated cylinder # 1 (# 2) during the intake process of the cylinders # 3 and # 4 that continue combustion during the cylinder deactivated operation. Based on this, the opening / closing of the intake valve 110a of the deactivated cylinder # 1 (# 2) is controlled. As a result, in the state in which the intake valve 110a of the idle cylinder # 1 (# 2) is opened in the intake process of the cylinders # 3 and # 4 that continue combustion during the cylinder idle operation, the idle cylinder # 1 (# 2) The connected connecting pipe 206a (206b) and the idle cylinder # 1 (# 2) can function as a Helmholtz type silencer. Therefore, the internal combustion engine 100 according to the present embodiment can reduce the sound having a desired frequency without increasing the number of silencers attached to the intake passage 202. Alternatively, the internal combustion engine 100 according to the present embodiment can omit a part of the silencer attached to the intake passage 202. As a result, the layout of the internal combustion engine 100 in the engine compartment is also advantageous.

  Further, in the present embodiment, during the cylinder deactivation operation, the intake valve 110a of the deactivated cylinder # 1 (# 2) is opened by the control device 140 during the intake process of the cylinders # 3 and # 4 that continue combustion. The predetermined frequency component of the intake sound that is reduced by the above is different from the frequency component that is reduced by the side branch type silencer 212 and the Helmholtz type silencer 214 attached to the intake passage 202. Therefore, the silencer attached to the intake passage 202 only needs to have a function of reducing a relatively high frequency sound generated during four-cylinder operation, and the number of silencers that reduce the low frequency component of the intake sound is reduced. be able to. Or the silencer which reduces the low frequency component of inhalation sound becomes unnecessary. As a result, the layout of the internal combustion engine 100 in the engine compartment is also advantageous.

  In the present embodiment, the control device opens the intake valve of the deactivated cylinder # 1 (# 2) after the piston of the deactivated cylinder # 1 (# 2) has finished descending. Thereby, the pressure inside the deactivated cylinder # 1 (# 2) when the intake valve 110a of the deactivated cylinder # 1 (# 2) is opened during the cylinder deactivated operation can be reduced. Therefore, the backflow of the intake air to the intake system 200 side due to the opening of the intake valve 110a of the deactivated cylinder # 1 (# 2) during the cylinder deactivation operation can be prevented. Therefore, noise due to the backflow of the intake air toward the intake system 200 can be suppressed.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can make various modifications or application examples within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  For example, in the above embodiment, the description has been given by taking the four-cylinder horizontally opposed internal combustion engine 100 as an example, but the configuration of the internal combustion engine is not limited to the above example. The internal combustion engine may be an internal combustion engine having various numbers of cylinders such as 6 cylinders, 8 cylinders, and 12 cylinders. Further, the internal combustion engine is not limited to the horizontally opposed type, and may be a V-type internal combustion engine or an in-line internal combustion engine as long as the internal combustion engine includes a connection pipe branched from the intake passage via the intake manifold and connected to each cylinder. It may be an institution.

100 Internal combustion engine 110a Intake valve 110b Exhaust valve 111 Cam mechanism 114 Four-cylinder operation cam 130 Cylinder deactivation operation cam 140 Controller 200 Intake system 202 Intake passage 202a Intake opening 204 Collector portions 206a, 206b, 206c, 206d Connection pipe 208 Air cleaner 210 Intake throttle valve 212 Side branch silencer 214 Helmholtz silencer 220 Intake port 250 Exhaust system

Claims (6)

A plurality of connecting pipes branched from the intake passage and respectively connected to a plurality of cylinders;
A control device for controlling the opening and closing of the intake valves of the some cylinders to be deactivated in a deactivation state in which the some cylinders are deactivated by stopping combustion in some cylinders of the plurality of cylinders;
With
The control device controls the opening and closing of the intake valves of the some cylinders based on the positions of the pistons of the some cylinders to be stopped during the intake process of the cylinders that continue combustion.
Internal combustion engine.   When the pistons of the some cylinders are located at positions where the predetermined frequency component of the intake noise can be reduced when the intake valves of the some cylinders to be stopped are opened, the control device The internal combustion engine according to claim 1, wherein an intake valve of a part of the cylinder is opened.   3. The internal combustion engine according to claim 1, wherein the control device opens the intake valves of the some cylinders after the pistons of the some cylinders to be stopped have been lowered.   The cross-sectional area and length of the connection pipe connected to the some cylinders to be stopped and the cylinder volume of the some cylinders when the intake valves of the some cylinders are opened The internal combustion engine according to any one of claims 1 to 3, wherein the predetermined frequency component is set to a value that can be reduced. The intake passage is provided with at least one silencer for reducing a predetermined frequency component of the intake sound,
In the inactive state, a predetermined frequency component of the intake noise that is reduced by opening the intake valves of the some cylinders by the control device during the intake process of the cylinders that continue combustion, and the silencer reduces the intake frequency Different from the frequency component
The internal combustion engine according to any one of claims 1 to 4.   The control device pauses some of the plurality of cylinders, and controls opening and closing of the intake valves of the some of the plurality of cylinders to be deactivated, thereby providing a plurality of predetermined intake noise sounds. The internal combustion engine according to any one of claims 1 to 5, wherein a frequency component is reduced.

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