JP6538440B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine that controls an internal combustion engine provided with a cylinder deactivation mechanism.

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

  Here, in the intake system of the internal combustion engine, pressure pulsation (hereinafter, this pulsation is also referred to as “intake pulsation”) occurs due to intake to each cylinder. For example, in a four-cylinder internal combustion engine, when the two cylinders are stopped, the number of intakes during two rotations of the crankshaft is halved, so the cycle of intake pulsations is also halved. As a result, the mode of vibration caused by the intake pulsation of the internal combustion engine changes from the second to the first, and the low-frequency intake noise becomes greater than in the four-cylinder operation. In general, since the cylinder deactivation control is performed in an operating region where the required torque of the internal combustion engine is small, the low frequency component of the intake noise at the time of cylinder deactivation operation is easily perceived as noise.

  On the other hand, there is an internal combustion engine provided with a silencer in an intake system. For example, Patent Document 1 discloses an internal combustion engine capable of reducing 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, a first intake passage communicating with the cylinders of one cylinder bank, and a second intake passage communicating with the cylinders of the other cylinder bank, a second intake passage communicating with the cylinders of the other cylinder bank, and a first intake passage A bypass passage communicating the second intake passage and an open / close valve provided upstream of the second resonator of the second intake passage are provided. The on-off valve is opened during all-cylinder operation and closed during cylinder deactivation operation. As a result, at the time of cylinder deactivation operation, the intake passage is configured to include two resonators, so low frequency noise can be reduced.

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

JP, 2010-163945, A JP-A-8-303312

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

  Further, in order to reduce low-frequency noise, a large-capacity or long-sized silencer is required, and installation is often difficult in terms of the layout in the engine compartment of the vehicle. Therefore, it is desirable to be able to reduce the low frequency sound without adding a new silencer or providing a communication passage as described in Patent Documents 1 and 2 anew.

  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 one aspect of the present invention, an intake throttle valve provided in an intake system of an internal combustion engine capable of executing cylinder deactivation control that deactivates some of a plurality of cylinders. A control unit for an internal combustion engine that performs control, the storage unit storing a target opening degree of a valve disposed on a passage that supplies intake air to a cylinder that is not stopped at the time of cylinder inactive operation; An internal combustion engine having a control unit for controlling the opening degree of the valve with reference to the opening degree, wherein the non-operating target opening degree is set based on a level of vibration noise and a fuel consumption rate in the cylinder non-operating state A control device is provided.

  The pause target opening degree may be set as the level of the vibration noise based on the level of low frequency intake noise that can be increased by transitioning from the all cylinder operation state to the cylinder halt state.

  The valve may be an intake throttle valve.

  The valve may be a valve provided in a connecting pipe that connects the collector portion and the non-stop cylinder.

  The valve may be a valve for generating tumble flow in the cylinder.

  The pause target opening degree may be set as the fuel consumption rate based on intake loss before and after the valve and a combustion delay loss in a non-stopped cylinder.

  The pause target opening degree may be set to a value where the vibration noise level is less than a predetermined value, the intake loss is less than the predetermined value, and the combustion delay loss is less than the predetermined value.

  The internal combustion engine includes an exhaust gas recirculation device, and the at-rest target opening degree is at least an opening degree of an EGR valve provided in an EGR passage connecting an exhaust system and an intake system, and an advance amount of the intake valve. It may be set together with one.

  According to the present invention, it is possible to reduce the noise at the time of cylinder deactivation operation of the internal combustion engine.

FIG. 1 is a schematic view 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 example of a structure of the intake system of an internal combustion engine. It is an explanatory view showing an intake pulsation which occurs in an intake system of an internal combustion engine. It is explanatory drawing which shows the vibration noise of an internal combustion engine. It is an explanatory view showing a measurement section of intake pulsation loss. FIG. 6 is an explanatory view showing a relationship between an intake throttle opening degree and an intake pulsation loss at the time of cylinder deactivation operation for each section. FIG. 6 is an explanatory view showing a relationship between an intake throttle opening degree and an intake pulsation loss at the time of all-cylinder operation in each section. It is explanatory drawing which shows the relationship between an intake throttle opening degree and an intake noise level. FIG. 6 is an explanatory view showing a relationship between an intake throttle opening degree and a fuel consumption rate. It is an explanatory view showing the relation between the intake throttle opening and the energy loss of an internal combustion engine. FIG. 6 is an explanatory view showing a relationship between an intake throttle opening degree and an intake loss. FIG. 6 is an explanatory view showing a relationship between an intake throttle opening degree and a combustion delay loss. FIG. 6 is an explanatory view showing a relationship between an intake throttle opening degree and a combustion loss. It is explanatory drawing which shows the relationship between an engine speed and an intake throttle opening degree. 5 is a flowchart showing an example of a control method of an intake throttle valve.

  The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. In the present specification and the drawings, components having substantially the same functional configuration will be assigned the same reference numerals and redundant description will be omitted. Also, components having substantially the same functional configuration may be distinguished by appending different alphabets to the end of the same reference numerals.

<1. Configuration of Internal Combustion Engine>
(1-1. Overall configuration)
First, an example of the entire configuration of an internal combustion engine according to the present embodiment will be described. FIG. 1 is a schematic view schematically showing a configuration example of an internal combustion engine 100. As shown in FIG. FIG. 1 is an explanatory view showing the configuration of a horizontally opposed internal combustion engine 100. As shown in FIG. In internal combustion engine 100 shown in FIG. 1, 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, an ignition plug 108, an intake valve 110a, an exhaust valve 110b, a cam mechanism 111, and a crankshaft 115. 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. Among these, two cylinders # 1 and # 3 constitute a cylinder group of the right bank, and the remaining two cylinders # 2 and # 4 constitute a cylinder group of the left bank.

  Cylinder head 101b is configured to close the end of cylinder # 1 and # 3 (# 2, # 4) in the axial direction on the side opposite to crankshaft 115 in each of right and left banks. Provided. A piston 104 is held movably forward and backward in each of the cylinders # 1, # 2, # 3 and # 4. A combustion chamber C is defined by the cylinder head 101 b and the crown surface of the piston 104 at the top dead center. The piston 104 performs linear reciprocating motion by combustion of fuel in the combustion chamber C. The linear reciprocating motion is transmitted as 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. Intake system 200 is branched from intake passage 202 provided with intake throttle valve 210, collector portion 204 connected to intake passage 202, and collector portion 204, and each cylinder # 1, # 2, # 3, # 4. And a plurality of connection pipes 206a, 206b, 206c, and 206d connected to each other. Further, the exhaust system discharges the combustion gas from each of the cylinders # 1, # 2, # 3, # 4. The cylinder head 101b is provided with an intake valve 110a and an exhaust valve 110b for each of the cylinders # 1, # 2, # 3, # 4.

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

  The cam mechanism 111 includes a cam shaft 112 and a cam 114 fixed to the cam shaft 112. 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 are provided with a return spring (not shown). The cam 114 rotates with the rotation of the camshaft 112, and the intake valve 110a and the exhaust valve 110b are opened when the cam crest of the cam 114 directly or indirectly pushes the intake valve 110a and the exhaust valve 110b.

  In the internal combustion engine 100 shown in FIG. 1, a rocker arm 30 is provided between the cam 114 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 cam 114 through the rocker arm 30. Further, when the intake valve 110a and the exhaust valve 110b are released from the pressing of the intake valve 110a and the exhaust valve 110b by the cam 114, they are returned to their original positions by the return spring.

  The cylinders # 1 and # 2 are provided with a cylinder deactivation mechanism 60 for preventing the pushing operation of the rocker arm 30 by the cam 114 from being transmitted to the intake valve 110a and the exhaust valve 110b. The cylinder deactivation mechanism 60 is configured, for example, using a hydraulic circuit. Specifically, a cylinder stopping mechanism capable of switching between engagement and disengagement between a pressed portion pressed by the cam 114 and a pressing portion pressed the intake valve 110a and the exhaust valve 110b by supply and discharge of hydraulic pressure can do. However, the cylinder deactivation mechanism 60 may be a mechanism other than the above configuration.

  The number of intake valves 110a and exhaust valves 110b provided in each of the cylinders # 1, # 2, # 3, and # 4 can be set as appropriate. In the present 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 valve 110a and the exhaust valve 110b is an intake port or an exhaust valve. Open and close ports In FIG. 1, a set of intake valves 110a is shown in each of the cylinders # 1, # 2, # 3 and # 4.

  Each cylinder # 1, # 2, # 3, # 4 is provided with a fuel injection valve (not shown) so as to reach the combustion chamber C. The fuel injection valve is fixed to, for example, the wall surface of the cylinder head 101b. The fuel injection valve is driven and controlled by a control device (not shown) to inject fuel into the combustion chamber C. Thus, an air-fuel mixture of the intake air and the fuel is formed in the combustion chamber C. Further, during the cylinder deactivation operation, fuel injection to the deactivation target is not performed. The fuel injection valve is not limited to the type in which the fuel is directly injected into the combustion chamber C. A fuel injection valve may be provided upstream of the intake port, and a preformed mixture may be introduced into the combustion chamber C from the intake port.

  An ignition plug 108 is provided in the cylinder head 101b so as to face the combustion chamber C of each of the cylinders # 1, # 2, # 3, and # 4. The spark plugs 108 are driven and controlled by a control device (not shown) to ignite the air-fuel mixture formed in each combustion chamber C. As a result, combustion occurs in the combustion chamber C, and the piston 104 is pushed down to rotate the crankshaft 115. In the present specification, ascent of the piston 104 means that the piston 104 moves to the combustion chamber C side, and descent of the piston 104 means that the piston 104 moves to the crankshaft 115 side.

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

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

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

  The intake throttle valve 210 is controlled by the controller 300 to adjust the flow rate of fresh air flowing through the intake passage 202. The intake throttle valve 210 is provided in the intake passage 202, and is axially rotated by an electric motor or the like to change the valve opening degree. As a result, the passage area of the intake passage 202 changes, and the flow rate of fresh air is adjusted. The opening degree of intake throttle valve 210 is determined based on the required torque and rotational speed of internal combustion engine 100 with reference to a target opening degree map created in advance.

  Further, the target opening degree of the intake throttle valve 210 is different between the four-cylinder operation and the cylinder deactivation operation. The idle target opening degree, which is the target opening degree of the intake throttle valve 210 at the time of cylinder inactive operation, is generally 4 in order to output from the internal combustion engine 100 the same torque as that at 4 cylinders operation even at 2 cylinders operation. The target opening degree of the intake throttle valve 210 during cylinder operation is made larger. As a result, at the time of cylinder deactivation operation, the charge amount of intake air per cylinder increases, and the torque generated per cylinder increases.

  The air cleaner 208 collects foreign substances contained in the introduced fresh air. On the downstream side of the air cleaner 208, an air flow meter (not shown) for measuring the flow rate of fresh air is provided. Further, an EGR (Exhaust Gas Recirculation) passage 231 for returning a part of the exhaust gas to the intake system 200 is connected to the upstream side of the intake throttle valve 210 of the intake passage 202. In this case, an EGR valve 233 is provided in the middle of the EGR passage 231. The EGR valve 233 is axially rotated by a stepping motor or the like controlled by the control device 300 to change the valve opening degree. Thereby, the passage area of the EGR passage 231 is changed, and the flow rate of the EGR gas is adjusted. The opening degree of the EGR valve 233 is determined with reference to a target opening degree map created in advance. The EGR valve 233 is not limited to a valve body of a shaft rotating type, and may be a direct acting valve body or the like.

  Collector portion 204 has a function of temporarily storing intake air and uniformly distributing intake air to cylinders # 1, # 2, # 3, and # 4. Connecting pipe 206a is branched from collector portion 204 and connected to cylinder # 1, and guides the intake air in collector portion 204 to cylinder # 1. An intake port 220 is interposed between the connection pipe 206a and the cylinder # 1, and the intake port 220 is opened and closed by an intake valve 110a. By opening the intake valve 110a while the piston 104 of the cylinder # 1 is lowered, intake air is drawn into the cylinder # 1. The intake valve 110 a is opened and closed by the rotation of the cam 114. The opening timing of the intake valve 110a is adjusted by operating the advance control mechanism 150 by the controller 300 to advance and retard the phase of the cam 114.

  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 sound of the frequency component by resonating a specific frequency component of the sound generated in the intake passage 202 in the side branch type silencer 212. The side branch type silencer 212 is specified by the fact that air vibrates inside when a specific frequency component enters into the side branch type silencer 212 and the energy of the sound is lost due to the friction loss with the side wall. Reduce the sound of frequency. The relationship between the length Ls of the side branch type silencer 212 and the resonance frequency fn can be expressed by the following equation (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: sound velocity

  The Helmholtz silencer 214 is a resonator having an open end of the tubular portion connected to the intake passage 202 and an expansion chamber (resonance chamber) on the other end side, and the tubular portion according to the frequency component to be reduced The length, cross-sectional area, or volume of the expansion chamber are set. In the Helmholtz type silencer 214, when a specific frequency component of the sound generated in the intake passage 202 enters into the Helmholtz type silencer 214, air in the tubular portion vibrates violently to The loss of sound energy due to the friction loss with the side wall reduces the sound of a specific frequency. The relationship between the length Lh of the tubular portion in the Helmholtz type silencer 214 and the resonance frequency fn can be expressed by the following equation (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: resonant frequency Lh: length of tubular portion Sh: cross-sectional area of tubular portion V: volume of expansion chamber n: order (n = 1, 2,...)
C: sound velocity

  The side branch type silencer 212 and the Helmholtz type silencer 214 respectively attenuate the pulsation of different frequency components. In addition, a plurality of side branch type silencers 212 and Helmholtz type silencers 214 may be installed in accordance with the frequency components to be attenuated. However, as the frequency of the sound to be muffled by the side branch type silencer 212 and the Helmholtz type silencer 214 becomes lower, it is necessary to use a long or large capacity silencer, and the layout limit in the engine compartment is limited. is there.

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

  The upper diagram of FIG. 3 shows a standing wave when the mode of vibration is secondary. When the order is second order, the intake opening 202a serving as the opening end is a node, and the end on the side of the cylinder # 1 (# 2, # 3, # 4) where intake is performed is an antinode, the entire length of the intake system 200 A standing wave of 4/3 wavelength is generated. On the other hand, the lower part of FIG. 3 shows a standing wave when the mode of vibration is primary. When the order is primary, the intake opening 202a serving as the opening end is a node, and the end on the side of the cylinder # 1 (# 2, # 3, # 4) where intake is performed is an antinode. A standing wave of double wavelength is generated, ie, a standing wave whose frequency is lower than that of the second order.

  Here, the basic order of the internal combustion engine 100 changes with the number of operating cylinders (intake timing). That is, the frequency of the intake pulsation generated in the intake system 200 due to the excitation force by the intake changes depending on the number of operating cylinders. Specifically, while the basic order during four-cylinder operation is secondary, the basic order during cylinder non-operating mode (two-cylinder operation) is primary, and the frequency of intake pulsation during cylinder non-operating mode is It is 1/2 of the frequency at the time of 4 cylinder operation. For example, when the revolution speed of the internal combustion engine 100 is 1800 rpm, the frequencies in the case of the second order and in the case of the first order are 60 Hz and 30 Hz, respectively.

  Thus, the frequency of intake pulsation during four-cylinder operation of internal combustion engine 100 is dominated by the frequency when the basic order is the second order, and the frequency of intake pulsation during cylinder deactivation operation is the primary order is the first order. The frequency in the case becomes dominant. Therefore, when the intake system 200 is designed on the basis of the reduction of intake noise during four-cylinder operation, the noise in the frequency range when the basic order is second order is reduced while the basic order is the first order. In this case, the sensitivity to sound in the frequency range becomes high, and the intake noise in the low frequency range becomes large.

  FIG. 4 is a conceptual diagram showing the strength of the vibration noise generated from the internal combustion engine 100 at the time of four-cylinder operation and at the time of cylinder non-operation (two-cylinder operation). When the internal combustion engine 100 switches from the four-cylinder operation to the two-cylinder operation, the low frequency component of the sound due to the intake pulsation becomes large, so the intensity of the low frequency vibration noise becomes relatively large. In order to attenuate low-frequency noise generated during two-cylinder operation with a side branch type silencer or 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 achieve the layout of the engine room.

<3. Control device for internal combustion engine>
Next, the control device 300 of the internal combustion engine 100 according to the present embodiment will be described. The control device 300 mainly includes a microcomputer and the like. As shown in FIG. 2, the control device 300 includes a storage unit 310 and a control unit 320.

(3-1. Storage unit)
The storage unit 310 is a storage device represented by a storage element such as a random access memory (RAM) or a read only memory (ROM). The storage unit 310 stores information on the target opening of the intake throttle valve 210, information on the target opening of the EGR valve 233, and information on the amount of advance of the intake valve 110a. In the present embodiment, the storage unit 310 includes a first throttle opening degree map that is information on the target opening degree during all-cylinder operation, and a second throttle opening degree map that is the information on the idle target opening degree. It is memorized. Similarly, the storage unit 310 stores information on the target opening degree and the advance angle amount in the all cylinder operation and information on the target opening degree and the advance angle amount in the cylinder non-operating mode.

(3-2. Control unit)
The control unit 320 may be, for example, a function realized by execution of a program by a microcomputer. Control unit 320 refers to the information on the corresponding target opening degree or advance amount according to the all-cylinder operation or the cylinder deactivation operation switched according to the rotation speed and the required torque of internal combustion engine 100, and intake throttle valve 210, The EGR valve 233 and the intake valve 110a are controlled. In particular, the control unit 320 controls the opening degree of the intake throttle valve 210, the opening degree of the EGR valve 233, and the advancing amount of the intake valve 110a so as to improve the fuel consumption characteristics while reducing the intake noise during cylinder deactivation operation. Control. Hereinafter, control of the target opening degree of the intake throttle valve 210 at the time of cylinder non-operating mode will be described.

(3-3. Control of the intake throttle valve at the time of cylinder deactivation)
The cylinder deactivation control is performed for the purpose of improving fuel consumption characteristics. In cylinder deactivation operation, generally, the intake throttle valve 210 is fully opened in order to suppress the occurrence of an intake loss (pumping loss). Ru. Therefore, intake pulsations generated in the intake system 200 at the time of cylinder deactivation operation are in the state of cylinder deactivation operation shown in FIG. On the other hand, in the internal combustion engine 100 according to the present embodiment, the target opening degree at rest is set based on the level of vibration noise and the fuel consumption rate at the time of cylinder rest operation. As a result, the improvement of the fuel consumption characteristic, which is the original purpose of the cylinder deactivation control, and the reduction of the low frequency noise generated at the time of the cylinder deactivation operation are both achieved.

  In the present specification, the "fuel consumption rate" means the amount of fuel necessary to obtain a predetermined output torque of the internal combustion engine. Further, in the present specification, "good fuel efficiency characteristics" means that the fuel consumption rate is low.

  In the internal combustion engine 100 according to the present embodiment, the intake throttle valve 210 is disposed in the intake passage 202 on the upstream side of the collector portion 204. The arrangement position of the intake throttle valve 210 is located near the end point with respect to the entire length of the intake system 200 starting from the intake opening 202a. Not limited to the internal combustion engine 100 according to the present embodiment, the intake throttle valve 210 is generally located near the end point of the entire length of the intake system 200. That is, the intake throttle valve 210 is located at a position close to the antinode of the pressure pulsation generated at the time of cylinder rest operation. In order to reduce the intake pulsation, it is effective to throttle the opening degree of the intake throttle valve 210 at the position of the antinode of the intake pulsation.

  5 to 7 are explanatory views showing the relationship between the intake pulsation loss and the opening degree of the intake throttle valve 210 in each section of the intake system 200. FIG. FIG. 5 is an explanatory view showing a measurement section of the intake pulsation loss. FIG. 6 is an explanatory view showing the total amount of the intake pulsation loss and the intake pulsation loss in each section of the intake system 200 at the time of the cylinder deactivation operation for each opening degree of the intake throttle valve 210. FIG. 7 is an explanatory view showing the total amount of the intake pulsation loss and the intake pulsation loss in each section of the intake system 200 at the time of all-cylinder operation, for each opening degree of the intake throttle valve 210. The intake pulsation loss in FIGS. 6 and 7 is an example in the case where the number of revolutions of the internal combustion engine 100 is 1800 rpm.

  As shown in FIGS. 5 to 7, in all cylinder operation and cylinder non-operating mode, in the region where the intake throttle opening degree is 30% or more, the intake pulsation loss is small and the effect of suppressing the intake pulsation is limited. On the other hand, during all-cylinder operation and cylinder non-operating mode, when the intake throttle opening degree becomes 20% or less, the intake pulsation loss increases before and after the intake throttle valve 210. In addition, the total of the intake pulsation loss in the entire intake system 200 is larger at the time of cylinder deactivation operation than at all cylinder operation. This is because the intake throttle valve 210 is located at a position close to the antinode of intake pulsation at the time of cylinder deactivation operation. Therefore, it can be understood that by throttling the opening degree of the intake throttle valve 210 at the time of cylinder deactivation operation, the low frequency component of the sound generated at the time of cylinder deactivation operation can be reduced.

  FIG. 8 shows the relationship between the intake throttle opening (%) and the intake noise level (dB) at the time of cylinder deactivation operation. In the example shown in FIG. 8, the intake noise level greatly changes (increases) in the region where the intake throttle opening degree is 0 to 30%. Further, in the region where the intake throttle opening degree exceeds 30%, the intake noise level does not change significantly. Assuming that the maximum allowable value of the intake noise generated during the cylinder deactivation operation is α, the intake throttle opening degree needs to be set to less than about 22 to 23%.

  On the other hand, if the opening degree of the intake throttle valve 210 is narrowed too much, the intake loss increases and a combustion delay in the cylinders # 3 and # 4 which are not stopped may occur, and the fuel consumption rate may increase. Since the original purpose of the cylinder deactivation control is to improve the fuel consumption characteristic, when the opening degree of the intake throttle valve 210 is narrowed, it is required to consider the reduction of the fuel consumption rate not to exceed the feasible range. Specifically, since the fuel consumption rate may be affected by the energy loss of the internal combustion engine 100, the target opening degree of the intake throttle valve 210 needs to be set so that the energy loss does not increase.

  FIG. 9 is an explanatory view showing a relationship between an intake throttle opening (%) and a BSFC (net fuel consumption rate: g / kWh) at the time of cylinder deactivation operation. FIG. 10 is an explanatory view showing a relationship between the intake throttle opening (%) and the energy loss of the internal combustion engine 100 at the time of the cylinder non-operating mode. In each figure, the solid line is data when the advance angle amount of intake valves 110a of cylinders # 3 and # 4 not stopped is 10 degrees, and the broken line is data when the advance angle amount is 20 degrees. . As shown in FIGS. 9 and 10, it can be seen that the fuel consumption rate increases as the energy loss of the internal combustion engine 100 increases. On the other hand, in the examples shown in FIG. 9 and FIG. 10, no significant change is seen in the fuel consumption rate and the energy loss in the region where the intake throttle opening degree exceeds about 12 to 13%.

  Here, the main elements of the energy loss of the internal combustion engine 100 are the intake loss, the combustion delay loss and the combustion loss. FIGS. 11 to 13 are explanatory views respectively showing the relationship between the intake throttle opening degree (%) and the intake loss (%), the combustion delay loss (%) or the combustion loss (%). Further, in each figure, the solid line is data when the advance angle amount of intake valves 110a of cylinders # 3 and # 4 not stopped is 10 degrees, and the broken line is data when the advance angle amount is 20 degrees. It is. As can be seen from FIGS. 11 to 13, the value of the combustion loss is relatively small compared to the values of the intake loss and the combustion delay loss, and the influence on the energy loss of the internal combustion engine 100 is relatively small. Therefore, it can be said that the main factors affecting the energy loss of the internal combustion engine 100 are the intake loss and the combustion delay loss.

  The intake loss decreases as the intake throttle opening increases. However, at the time of cylinder deactivation operation, the required torque of the internal combustion engine 100 is small, and the flow rate of intake air passing through the intake throttle valve 210 is small. Therefore, in the example shown in FIG. 11, the boost action before and after the intake throttle valve 210 is substantially zero by setting the opening degree of the intake throttle valve 210 to about 20 degrees. Therefore, it is understood that when the opening degree of the intake throttle valve 210 is 20 degrees or more, the sensitivity of the intake loss to the opening degree of the intake throttle valve 210 is lost.

  Further, the combustion delay loss is deteriorated when the ratio of EGR gas occupied in the intake air (EGR rate) becomes excessive. Therefore, if the opening degree of the EGR valve 233 is increased to increase the external EGR amount, or if the timing to open the intake valve 110a is advanced to increase the internal EGR amount, the combustion delay loss may increase. is there. The external EGR amount and the internal EGR amount are adapted in association with the intake throttle opening according to the target EGR rate. In the example shown in FIG. 12, the combustion delay loss increases in the region where the intake throttle opening is around 10%.

  That is, the intake throttle opening degree that can reduce both the intake loss and the combustion delay loss can be a compatible value that can improve the fuel consumption characteristic. In the present embodiment, the intake throttle opening degree at which the energy loss of the internal combustion engine 100 is reduced is set as the target opening degree at rest based on the intake loss and the combustion delay loss in the range where the intake noise level does not exceed the maximum allowable value. Be done. As a result, it is possible to achieve both the improvement of the fuel efficiency characteristic and the reduction of the intake noise at the time of the cylinder deactivation operation.

  For example, as shown in FIG. 14, an intake throttle opening degree (solid line A) at which the intake sound level becomes the maximum allowable value is set in the range of the rotational speed of the internal combustion engine 100 at which cylinder deactivation control can be performed. Thereafter, in the range below the maximum allowable value, the intake throttle opening degree, the advance amount of the intake valve 110a, and the opening degree of the EGR valve 233 are adapted so as to optimize the fuel consumption characteristic. As a result, the intake throttle opening degree (broken line B) at which the fuel efficiency characteristic is optimal is set. In this way, the pause target opening degree is set to a value where the intake noise level is less than the predetermined maximum allowable value α, and the intake loss and the combustion delay loss are less than the predetermined values.

  The idle target opening set in this manner is obtained in advance by simulation using an actual machine, and stored in the storage unit 310 as a second throttle opening map. During all-cylinder operation of internal combustion engine 100, control unit 320 determines the opening degree of intake throttle valve 210 based on the rotational speed of internal combustion engine 100 with reference to the stored first throttle opening degree map, and performs intake operation. The throttle valve 210 is controlled.

  Further, control unit 320 refers to the stored second throttle opening degree map when internal combustion engine 100 is switched to the cylinder non-operating mode, and controls intake torque of intake throttle valve 210 based on the rotational speed of internal combustion engine 100. The opening degree is determined, and the control of the intake throttle valve 210 is performed. As a result, it is possible to improve the fuel consumption characteristics while reducing the low frequency intake noise generated at the time of the cylinder deactivation operation.

(3-4. Flowchart)
FIG. 15 is an example of a flowchart showing a control method of the intake throttle valve 210 executed by the control device 300.

  At step S12, control unit 320 determines whether or not internal combustion engine 100 is in the cylinder deactivation operation state. Whether the internal combustion engine 100 is in the all cylinder operation or in the cylinder deactivation operation is separately determined in accordance with the required torque, the number of revolutions, etc. of the internal combustion engine 100, and the control unit 320 reads the current operation state. Make a decision.

  When internal combustion engine 100 is in the all-cylinder operating state (S12: No), control unit 320 proceeds to step S18, and refers to the first throttle opening map to determine intake air based on the rotational speed of internal combustion engine 100 and the like. The target opening of the throttle valve 210 is determined. On the other hand, when internal combustion engine 100 is in the cylinder non-operating state (S12: Yes), control unit 320 proceeds to step S14 and refers to the second throttle opening map based on the rotational speed of internal combustion engine 100 etc. The target opening degree of the intake throttle valve 210 is determined.

  After the target opening degree of the intake throttle valve 210 is determined in step S14 or step S18, the process proceeds to step S16, and the control unit 320 controls the opening degree of the intake throttle valve 210 according to the target opening degree. As a result, it is possible to reduce the low frequency intake noise generated at the time of the cylinder deactivation operation. When the target opening degree of intake throttle valve 210 is determined in step S14 or step S18, the target opening degree does not significantly change in the case of switching between all cylinder operation and cylinder deactivation operation, etc. The target opening may be corrected as appropriate using a predetermined time constant.

<4. Summary>
As described above, in the internal combustion engine 100 according to the present embodiment, the opening degree of the intake throttle valve 210 at the time of cylinder deactivation operation reduces low frequency intake noise generated at the time of cylinder deactivation operation, and the fuel consumption rate It is set to reduce. Therefore, the internal combustion engine 100 according to the present embodiment can reduce vibration noise at the time of cylinder deactivation operation without increasing the number of silencers attached to the intake passage 202. Thereby, the layout of the internal combustion engine 100 in the engine chamber is also advantageous.

  Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that those skilled in the art to which the present invention belongs can conceive of various modifications or applications within the scope of the technical idea described in the claims. Of course, it is understood that these also fall within the technical scope of the present invention.

  For example, although the four-cylinder horizontally opposed internal combustion engine 100 has been described as an example in the above embodiment, 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 six cylinders, eight cylinders, twelve cylinders, etc. Further, the internal combustion engine is not limited to the horizontally opposed type, and may be a V-type internal combustion engine or a serial internal combustion engine.

  Further, in the above embodiment, the intake throttle valve 210 is provided in the intake passage 202 on the upstream side of the collector portion 204, but the arrangement position of the intake throttle valve 210 is not limited to the above example. For example, according to the present invention, connection pipe 206 connected to each cylinder # 1, # 2, # 3, # 4 from collector portion 204 or intake throttle valve 210 is provided for each bank of the internal combustion engine. Can be applied. That is, regardless of the position of intake throttle valve 210, the target opening degree of intake throttle valve 210 for controlling the amount of intake supplied to the cylinders not being stopped during cylinder deactivation operation is the intake noise level and the fuel consumption rate. By setting based on this, it is possible to improve the fuel consumption characteristic while reducing the intake noise at the time of the cylinder deactivation operation.

  Further, in the above embodiment, the fuel consumption characteristic is improved while reducing the low frequency intake noise by adjusting the opening degree of the intake throttle valve 210 at the time of cylinder rest operation, but the valve to be controlled is Is not limited to the intake throttle valve 210. For example, the valve to be controlled may be a TGV (Tamble Generation Valve) for making the intake flow supplied to cylinders # 3 and # 4 that are not to be stopped a tumble flow. The TGV is a valve provided in the connecting pipes 206a, 206b, 206c, and 206d connected to the cylinders # 1, # 2, # 3, and # 4 from the collector unit 204. Among them, the cylinder # 3 which is not a target for stopping By reducing the flow passage area of the connection pipes 206c and 206d by the TGVs provided on the connection pipes 206c and 206d connected to # 4 and # 4, the same effect as that of the above embodiment can be obtained.

60 cylinder deactivation mechanism 100 internal combustion engine 110a intake valve 110b exhaust valve 150 advance angle control mechanism 200 intake system 202 intake system 202 intake passage 202a intake opening 204 collector section 206a, 206b, 206c, 206d connection pipe 208 air cleaner 210 intake throttle valve 212 side branch type muffle Unit 214 Helmholtz type silencer 220 Intake port 231 EGR passage 233 EGR valve 250 Exhaust system 300 Control unit 310 Storage unit 320 Control unit

Claims (6)

A control device for an internal combustion engine that controls an intake throttle valve provided in an intake system of an internal combustion engine capable of performing cylinder deactivation control that can perform cylinder deactivation control that deactivates some of a plurality of cylinders.
A storage unit for storing a target opening degree at stop of a valve disposed on a passage for supplying intake air to a cylinder not stopped at the time of cylinder inactive operation;
A control unit that controls the opening degree of the valve with reference to the target opening degree at rest time;
The resting target opening degree, the level of noise and vibration in the cylinder deactivation state, and,
As the fuel consumption rate , intake loss before and after the valve, and combustion delay loss in a non-stopped cylinder
A control device for an internal combustion engine, which is set based on. The non-operating target opening degree is set to a value where the vibration noise level is less than a predetermined value, the intake loss is less than a predetermined value, and the combustion delay loss is less than a predetermined value. The control device of an internal combustion engine according to 1 . A control device for an internal combustion engine that controls an intake throttle valve provided in an intake system of an internal combustion engine capable of performing cylinder deactivation control that can perform cylinder deactivation control that deactivates some of a plurality of cylinders.
A storage unit for storing a target opening degree at stop of a valve disposed on a passage for supplying intake air to a cylinder not stopped at the time of cylinder inactive operation;
A control unit that controls the opening degree of the valve with reference to the target opening degree at rest time;
The valve is a valve provided in a connecting pipe connecting a collector portion and the non-stop cylinder to generate tumble flow in the non-stop cylinder.
The control device for an internal combustion engine, wherein the target opening time at rest is set based on a level of vibration noise and a fuel consumption rate in a cylinder non-operating state. As the level of the vibration noise, based on the level of the low frequency suction noise may be increased by the transition to the cylinder deactivation state from the full cylinder operation state, the resting target opening degree is set, according to claim 1 A control device of an internal combustion engine according to any one of 3 . The control device for an internal combustion engine according to any one of claims 1 to 4 , wherein the valve is an intake throttle valve. The internal combustion engine comprises an exhaust gas recirculation system;
The resting target opening degree, the opening degree of the EGR valve provided in the EGR passage connecting the exhaust system and the intake system, and is set with at least one of the advance amount of the intake valve, according to claim 1 to 5 The control device for an internal combustion engine according to any one of the above.

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