JP2009191698A - Intake system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain a deviation between cylinders of a filling quantity of intake air, by suitably generating negative pressure without increasing cost. <P>SOLUTION: In an engine 200, an impulse valve 224 is arranged in an intake pipe 204. This impulse valve 224 is connected with a mutually independent communicating tube 206 communicating with the respective cylinders via an intake port so as to form a radial shape in its connecting part. The impulse valve 224 is constituted so that a valve element 224B forming a communicating part 224B1 rotates around the predetermined axis inside a case 224A. An opening part on the impulse valve side of the communicating tube corresponding to the respective cylinders is arranged at an equal interval around this axis, and is constituted so that one opening part selectively communicates with the intake pipe 204 via the communicating part 224B1 in response to rotation of the valve element 224B. The pipe length of the communicating tube 206 is also mutually substantially equally constituted so as to restrain the deviation between the cylinders of an intake quantity. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technical field of an intake system of an internal combustion engine capable of realizing inertia supercharging.

  As this type of system, a system having an intake control valve in each of a plurality of cylinders has been proposed (for example, see Patent Document 1). According to the intake control device for an internal combustion engine disclosed in Patent Document 1 (hereinafter referred to as “conventional technology”), an intake control valve is provided in an intake passage that communicates with each cylinder, and the valve opening period of the intake valve is long. The intake control valves are connected in the same phase between cylinders that do not overlap. For this reason, it is supposed that the fuel consumption and the output are improved by the intake air control, and the configuration is simplified and the space is saved.

  A technique has also been proposed in which the joining point position where the inertial supercharging branch part joins is variable according to the number of revolutions (see, for example, Non-Patent Document 1).

JP 7-71277 A Japanese Utility Model Publication No. 61-173730

  In the prior art, as many intake control valves as the number of cylinders are required, and it is difficult to avoid an increase in cost when some of them are interconnected. In order to avoid such problems, when a single intake control valve is provided upstream of the communication pipe communicating with each cylinder, an increase in cost can be avoided, but the dead volume downstream of the intake control valve is large. Therefore, the generation of negative pressure is hindered. In any case, since the lengths of the pipes that lead the intake air between the cylinders are different, the intake charge amount in the inertia supercharging is easily different between the cylinders. For example, drivability is reduced due to torque fluctuation between the cylinders. Inevitable.

  The present invention has been made in view of the above-described problems, and is an intake system for an internal combustion engine that can generate a negative pressure suitably without causing an increase in cost and can suppress an inter-cylinder deviation in the intake charge amount. It is an issue to provide.

  In order to solve the above-described problems, an intake system for an internal combustion engine according to the present invention is an intake system for an internal combustion engine that is mounted on a vehicle and includes a plurality of cylinders and a common intake passage shared between the plurality of cylinders. Each of which is configured as a pipe line having a first opening and a second opening, and is configured to be able to communicate with each of the plurality of cylinders in the first opening, and the second opening. A plurality of first intake passages each having a portion arranged around a predetermined axis, and a valve body rotatable around a rotation axis defined along the axis, in the process of rotating the valve body And an intake control valve capable of selectively connecting the shared intake passage and the second opening in one of the first intake passages.

  The "internal combustion engine" according to the present invention has a plurality of cylinders, and various fuels such as gasoline, light oil, various alcohols, or a mixed fuel of various alcohols and gasoline, or the like in each of the cylinders, or The force generated when an air-fuel mixture containing various fuels explodes or burns can be taken out as a driving force through a physical or mechanical transmission path such as a piston, a connecting rod and a crankshaft. It is a concept that encompasses various institutions.

  The “shared intake passage” in the intake system of the internal combustion engine according to the present invention includes intake air (that is, intake air that is sucked from the outside as at least a part of the concept, and the intake air itself or, for example, an EGR device or the like) For example, when an exhaust gas recirculation device is provided, various forms such as a mixture of EGR gas (that is, a part of exhaust gas) and the intake air can be adopted in accordance with the open / close state of a flow rate adjusting means such as an EGR valve. As a preferred embodiment, for example, an air cleaner, a throttle valve (that is, an intake throttle valve), a surge tank, or the like can be appropriately provided, for example, in a single or a plurality of tubular members. It can take a form. Further, as a preferred embodiment, the internal combustion engine according to the present invention includes a part of the common intake passage excluding a part to be provided in the exhaust system such as a turbocharger (of course, a turbine or the like). In this case, the downstream side (note that “downstream” and “upstream” are one of the directional concepts based on the direction of intake air flow. The downstream side is the cylinder side), and an intake air cooling means such as an intercooler may be provided.

  In the internal combustion engine according to the present invention, the common intake passage is shared by a plurality of cylinders. Here, the plurality of cylinders sharing the intake passage is not limited to all the cylinders provided in the internal combustion engine according to the present invention, and conceptually indicates at least a plurality of cylinders among the plurality of cylinders provided in the internal combustion engine. For example, when the cylinder arrangement of the internal combustion engine according to the present invention has a so-called V-type aspect, for example, a plurality of cylinders belonging to two cylinder groups (also referred to as banks) that face each other at a predetermined included angle. The cylinder may correspond to “a plurality of cylinders” according to the present invention. For example, when the cylinder arrangement has a so-called in-line type, all the cylinders (of course, conceptually, some It may be a cylinder) may correspond to “a plurality of cylinders” according to the present invention.

  The first intake passage is a mutually independent conduit having first and second openings corresponding to each of the plurality of cylinders, and each of the corresponding cylinders via the first opening, For example, communication is possible via an intake port or the like. In this case, the first and second openings may be portions corresponding to the end portions of the first intake passage as a preferred embodiment.

  In view of being able to communicate with each of the plurality of cylinders, the first intake passage may be a pipeline including an intake port as a preferred embodiment. In this case, on the path of the first intake passage, a means such as an intake valve that can control the communication state with the inside of the cylinder according to the open / close state may be provided. The second openings in each of the plurality of first intake passages are arranged around a predetermined axis regardless of whether they are real or virtual.

  On the other hand, an intake system for an internal combustion engine according to the present invention has a valve body that is rotatable about a rotation axis that is defined along the above-mentioned axis (which may coincide with the axis). An intake control valve having a function as a multi-way valve is provided. The configuration of the intake control valve is not particularly limited as long as it has the valve body, and may be the valve body itself, or a housing portion that houses the valve body, or a driving force related to rotation of the valve body. For example, a driving force applying means such as various actuators may be appropriately included.

  Here, in particular, the valve element provided in the intake control valve has a second opening portion in one of the common intake passage and the first intake passage described above in the process of rotating around the rotation axis. (That is, the openings arranged around the axis) can be selectively connected. Therefore, according to the intake system of the present invention, the shared intake passage and the first intake passage can be communicated with each other by rotating the valve body in the intake control valve.

  Note that the first intake passage is connected to the intake control valve as a preferred form, and is not provided for communication with the common intake passage (that is, not in a state selected by the intake control valve). As a preferred embodiment, the second opening is blocked from contact with outside air including intake air.

  According to such an intake system for an internal combustion engine according to the present invention, it is possible to perform inertial supercharging (also referred to as pulse supercharging or impulse charge) using the pulsation of intake air.

  Here, the inertia supercharging is, as a suitable form, for example, a cylinder corresponding to a cylinder (hereinafter referred to as “intake cylinder” as appropriate) that is in the intake stroke at the time immediately after the opening of the intake valve. The communication between the one intake passage and the common intake passage is cut off (for example, as a preferred form, the one first intake passage while the one intake passage excluding the first intake passage communicates with the common intake passage). The intake valve corresponding to the passage is closed, or the communication between the shared passage and all the first intake passages is shut off (such a valve body position may be provided, and the valve body is For example, after the intake valve has been opened, an appropriate time lapse (may be defined as an angle concept based on the crank angle or the like), the first corresponding to the intake cylinder 1 communication between the intake passage and the common intake passage (ie, Preferably, a positive pressure wave of intake air is generated by, for example, communicating with the intake control valve downstream at a negative pressure and the intake control valve upstream at an atmospheric pressure or higher. Reflected as a negative pressure wave near the combustion chamber entrance of each cylinder that can be considered, and this negative pressure wave is reflected again at the open end, for example, at an opening such as a surge tank arranged in series or in parallel with the common intake passage. When natural intake is performed using the pulsation of intake air that can take the form of a secondary positive pressure wave, etc. that occurs (in a preferred form, intake air basically pulsates regardless of the presence or absence of an intake control valve) However, the pulsation caused by the rotation control of the valve body in the intake control valve is a pulsation stronger than this type of pulsation). Inhalation line In taking into the cylinder refers to (i.e., supercharging to) the like.

  In order to suitably realize this kind of inertia supercharging, the formation of negative pressure is important. However, according to the intake system for an internal combustion engine according to the present invention, the pipe line communicating with the intake cylinder at the stage of formation of the negative pressure Can be made only the first intake passage corresponding to the intake cylinder. That is, the dead volume can be kept extremely small, and a suitable negative pressure can be formed in a state where the communication between the intake cylinder and the common intake passage is blocked. For this reason, when the first intake passage corresponding to the intake cylinder is communicated with the common intake passage, for example, a positive pressure wave with a large amplitude can be generated, which improves the intake charge amount or the charge efficiency by inertia supercharging. Such practical benefits are significant.

  In the intake system for an internal combustion engine according to the present invention, the plurality of cylinders can be communicated with the common intake passage by rotating the valve body. Therefore, it is not necessary to install a plurality of intake control valves so as to correspond to each cylinder, and an increase in cost is avoided.

  Further, looking at the configuration of the first intake passage, at least the second opening is disposed adjacent to each other around the rotation axis of the valve body in the intake control valve, and the first intake passage is arranged in a cylinder arrangement. Whatever the form, at least the connection position with the common intake passage (that is, it can be treated as substantially equivalent to the installation position of the intake control valve) is directed radially to each cylinder. For this reason, according to the present invention, it is possible to make the transfer characteristic of intake air uniform between the first intake passages without enlarging the intake system to a practically problematic level. Various problems such as a decrease in drivability caused by a torque fluctuation accompanying a cylinder-to-cylinder deviation of the intake charge amount that can be manifested in a type intake manifold intake system, etc., a deterioration in emissions, a deterioration in fuel consumption, and the like are preferably avoided. That is, according to the intake system for an internal combustion engine according to the present invention, it is possible to suitably generate a negative pressure without causing an increase in cost and to suppress an inter-cylinder deviation in the intake charge amount.

  In one aspect of the intake system for an internal combustion engine according to the present invention, the second openings are arranged around the axis in the order in which the intake stroke is performed.

  According to this aspect, since the second openings are arranged around the axis in the order in which the intake stroke is performed (that is, the same applies to the compression stroke, the expansion stroke, and the exhaust stroke), the valve of the intake control valve The body only needs to rotate around the rotation axis in a certain direction, and the control is prevented from becoming complicated due to the change in the rotation direction. In addition, when the valve body only needs to rotate in a constant direction in this way, the cylinder to be used for communication with the shared intake cylinder can be switched as quickly as possible, and the response speed can be optimized. Practical benefits are also great in terms that can be achieved. Furthermore, in this case, the dimensional accuracy and physical or mechanical strength of the valve body are not required as compared with a structure in which the valve body constantly requires indefinite rotation, and an increase in cost can be suppressed.

  In another aspect of the intake system for an internal combustion engine according to the present invention, the second openings are arranged at equal intervals around the axis.

  According to this aspect, since the second openings are arranged at equal intervals, the valve body of the intake control valve can always be rotated at a constant angle. For this reason, the load on the drive system and the control system required for driving the intake control valve is alleviated, and the control accuracy can be improved.

  In another aspect of the intake system of the internal combustion engine according to the present invention, the first intake passage is configured such that the pipe length is substantially equal for each of the first intake passages.

  According to this aspect, the first intake passage is configured such that the pipe lengths thereof are substantially equal between the plurality of first intake passages, and therefore, the inter-cylinder deviation of the intake charge amount or the intake charge efficiency. Is suppressed, and torque fluctuations are suppressed as much as possible. That is, the drivability of the vehicle can be improved as much as possible.

  Here, “substantially equal” includes strictly equality, and further, the fact that the degree of variation between the two does not reveal any trouble in practice, or that some trouble has occurred. The fact that it is acceptable is determined in advance experimentally, empirically, theoretically or based on simulations, or within such a range that such a practical judgment can be made. It is a concept that encompasses In other words, the “schematic” in this case means that the pipe length that can suppress the deviation of the intake charge amount or the intake charge efficiency within the allowable range is within a range that is practically finite and cannot be clearly defined. It is an expression that originates in the fact that it can exist, and is based on a clear concept to the last, and does not deny the clarity of the invention.

  For example, the length of the first intake passage is determined so that the deviation of the intake charge amount or the intake charge efficiency between the first intake passages is determined in advance by experimental, empirical, theoretical or simulation based on the simulation. A predetermined range (which may be defined in the dimension of length, from the reference value or the average value) that various problems such as a decrease in emissions, a deterioration in emissions, a deterioration in fuel consumption, etc. may fall within the allowable range It may be determined so as to fall within a dimension (such as a deviation rate). At this time, the length of the first intake passage may be determined in consideration of the material, shape and pipe diameter of each first intake passage or the three-dimensional arrangement between the first intake passages.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

<Embodiment of the Invention>
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
<Embodiment>
<Configuration of Embodiment>
First, the configuration of the engine system 10 according to the first embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram conceptually showing the configuration of the engine system 10.

  In FIG. 1, an engine system 10 is mounted on a vehicle (not shown) and includes an ECU (Electronic Control Unit) 100 and an engine 200.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and is configured to be able to control the overall operation of the engine 200. In accordance with the stored control program, the basic drive control described later can be executed.

  The engine 200 is an in-line four-cylinder gasoline engine that is an example of an “internal combustion engine” according to the present invention that uses gasoline as fuel. The outline of the engine 200 will be described. The engine 200 has a configuration in which four cylinders 202 are arranged in parallel in a cylinder block 201. Then, the air-fuel mixture containing the fuel is compressed in the compression process in each cylinder, and the force generated when ignited by the ignition operation of the ignition device 203 is applied to the crankshaft (not shown) via a piston and a connecting rod (not shown), respectively. It is configured to be converted into a rotational motion. The rotation of the crankshaft is transmitted to drive wheels of a vehicle on which the engine system 10 is mounted, and the vehicle can travel.

  Below, the principal part structure of the engine 200 is demonstrated with a part of the operation | movement. Since the configurations of the individual cylinders 202 are equal to each other, only one cylinder 202 will be described here. However, when each cylinder is distinguished and expressed, these four cylinders are expressed as “first cylinder”, “second cylinder”, “third cylinder”, and “fourth cylinder” in order from the left side in the drawing. To do. Note that supplementarily, the engine 200 is configured such that each stroke is repeatedly executed in the order of the first cylinder → the third cylinder → the fourth cylinder → the second cylinder. That is, when the intake stroke is performed in the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder, the cylinders that reach the intake stroke before and after each of the cylinders in time series are respectively the third cylinder. , The fourth cylinder, the second cylinder, and the first cylinder.

  In FIG. 1, intake air that is air guided from the outside is guided to an intake pipe 204 that is an example of a “shared intake passage” according to the present invention. The intake pipe 204 is provided with a throttle valve 205 capable of adjusting the amount of intake air guided to the intake pipe 204. The throttle valve 205 is a rotary valve that is configured to be rotatable by a driving force supplied from a throttle valve motor (not shown) that is electrically connected to the ECU 100 and controlled by the ECU 100 at the upper level. The rotational position is continuously controlled from a fully closed position where the upstream and downstream portions of the intake pipe 204 at the boundary are substantially blocked to a fully open position where the intake pipe 204 communicates almost entirely. As described above, in the engine 200, the throttle valve 205 and the throttle valve motor constitute a kind of electronically controlled throttle device.

  The intake pipe 204 is connected to the communication pipe 206 on the downstream side of the throttle valve 205. The communication pipe 206 includes a communication pipe 2061 corresponding to the first cylinder, a communication pipe 2062 corresponding to the second cylinder, a communication pipe 2063 corresponding to the third cylinder, and a communication pipe 2064 corresponding to the fourth cylinder. Thus, it is configured to communicate with each cylinder while maintaining independence (strictly speaking, communication is performed when an intake valve 207 in which a valve body is installed at an intake port described later) is opened. The intake pipe 204 and one of the four communication pipes are configured to selectively communicate with each other by the action of an impulse valve (see “IPV” in the drawing) 224 described later.

  In the following description, when individual communication pipes are distinguished, they are appropriately expressed as communication pipes 206x (x = 1, 2, 3 or 4) without distinguishing individual communication pipes. When collectively calling, it will express as the communication pipe | tube 206 suitably.

  The communication pipe 206 communicates with each intake port (not shown) corresponding to each cylinder 202, and the intake air guided to the intake pipe 204 is connected to the intake port corresponding to each cylinder via the communication pipe 206. It is the composition led to. Although omitted in FIG. 1, in the following description, the intake ports corresponding to the first cylinder, the second cylinder, the third cylinder, and the fourth cylinder are referred to as IP1, IP2, IP3, and IP4, respectively. And In the present embodiment, each intake port is not included in the communication pipe 206. However, the intake port may be included in the communication pipe 206, and in any case, it is not related to the essential part of the present invention. is there.

  In each intake port, an injector injection valve (not shown) for fuel injection is exposed so that gasoline as fuel can be injected into the intake port. The injector drive system is electrically connected to the ECU 100 and is controlled by the ECU 100 to the upper level. That is, the operation of the injector is controlled by the ECU 100. The fuel injected through the injector is mixed to some extent with the intake air at the intake port, and is sucked into the cylinder 202 in the intake stroke as the above-described mixture. That is, this air-fuel mixture is an example of “intake” according to the present invention. Note that the intake air-fuel mixture is further mixed in the intake stroke and the subsequent compression stroke, and ignited and ignited by ignition control of the ignition device 203 (controlled by the ECU 100) performed in the vicinity of the compression TDC ( That is, it is configured to explode).

  In this embodiment, the injector is a so-called electronically controlled port injector, and fuel is injected into the intake port. However, the fuel injection mode is not limited in any way. For example, this type of port injector is used. Instead of or in addition, an in-cylinder direct injection system composed of, for example, a common rail system or a unit injector that can inject fuel directly into the high-temperature and high-pressure cylinder 202 may be employed.

  The communication state between the intake port and the cylinder 202 is controlled by an intake valve 207 provided in each intake port. The intake valve 207 is fixed to the intake camshaft 208 that rotates in conjunction with the crankshaft. The cam profile of the intake cam 209 that has an elliptical cross section perpendicular to the extending direction of the intake camshaft 208 (in short, The opening / closing characteristics are defined according to the shape), and the intake port and the inside of the cylinder 202 can communicate with each other when the valve is opened.

  On the other hand, the burned mixture or the partially unburned mixture is led to the exhaust manifold 213 through the exhaust port (not shown) as exhaust when the exhaust valve 210 that opens and closes in conjunction with the opening and closing of the intake valve 207 is opened. It is configured to be written. The exhaust valve 210 is fixed to the exhaust camshaft 211 that rotates in conjunction with the crankshaft, and the cam profile of the exhaust cam 212 having an elliptical cross section perpendicular to the extending direction of the exhaust camshaft 211 (in short, The opening / closing characteristics are defined according to the shape), and the exhaust port and the cylinder 202 can be communicated with each other when the valve is opened. The exhaust gas collected in the exhaust manifold 213 is supplied to the exhaust pipe 214 communicating with the exhaust manifold 213.

  A turbine 216 is installed in the exhaust pipe 214 so as to be accommodated in the turbine housing 215. The turbine 216 is a ceramic impeller configured to be rotatable about a predetermined rotation axis by the pressure of exhaust gas (that is, exhaust pressure) guided to the exhaust pipe 214. The rotating shaft of the turbine 216 is shared with the compressor 218 installed in the intake pipe 204 so as to be accommodated in the compressor housing 217. When the turbine 216 is rotated by exhaust pressure, the compressor 218 is also centered on the rotating shaft. It is configured to rotate.

  The compressor 218 is configured to be able to pump and supply intake air sucked into the intake pipe 204 from the outside through an air cleaner (not shown) to the downstream side by the pressure accompanying its rotation. The so-called supercharging is realized by the air pumping effect. That is, in the engine 200, the turbine 216 and the compressor 218 constitute a kind of turbocharger. In the following description, the term “turbocharger” will be used as appropriate as a comprehensive concept including the turbine 216 and the compressor 217.

  A three-way catalyst 219 is installed in the exhaust pipe 214. The three-way catalyst 219 is a catalytic converter that can purify HC (hydrocarbon), CO (carbon monoxide), and NOx (nitrogen oxide) in the exhaust gas simultaneously or continuously. Further, a water temperature sensor 220 is disposed in the cylinder block 201 that accommodates the cylinder 202. Inside the cylinder block 201, a water jacket as a cooling water flow path for cooling the cylinder 202 is stretched. Inside the water jacket, LLC as cooling water is circulated and supplied by the action of a circulation system (not shown). ing. The water temperature sensor 220 has a configuration in which a part of the detection terminal is exposed inside the water jacket, and is configured to be able to detect the temperature of the cooling water. The water temperature sensor 220 is electrically connected to the ECU 100, and the detected coolant temperature is grasped by the ECU 100 at a constant or indefinite period.

  A hot wire type air flow meter 221 capable of detecting the mass flow rate of the intake air is installed on the upstream side of the compressor 218. The air flow meter 221 is electrically connected to the ECU 100, and the detected intake air amount is grasped by the ECU 100 at a constant or indefinite period. In the present embodiment, the detected intake air amount is uniquely related to the amount of intake air (ie, the intake air amount) sucked into the cylinder 202, and is an index that defines the actual load of the engine 200. Treated as a value.

  In the intake pipe 204, an intercooler 222 is installed on the downstream side of the compressor 218 and the upstream side of the throttle valve 205. The intercooler 222 has a heat exchange wall inside thereof, and when supercharged intake air passes (the same is true even in a low rotation region where the compressor 218 does not act substantially), The intake air can be cooled by heat exchange via the heat exchange wall. The engine 200 can increase the density of the intake air by the cooling by the intercooler 222, so that the supercharging via the compressor 218 can be performed more efficiently.

  Here, a surge tank 223 is installed on the downstream side of the throttle valve 205 in the intake pipe 204. The surge tank 223 suppresses irregular pulsation of the intake air supplied while appropriately receiving the above-described turbocharger supercharging action, and stably supplies the intake air to the downstream side (that is, the cylinder 202 side). At the same time, it is a storage means configured to be able to reverse the phase of the negative pressure wave when performing inertial supercharging described later. The above-described communication pipe 206 is connected to the intake pipe 204 on the downstream side of the surge tank 223. It is connected. However, since the intake air is basically supplied to the cylinder 202 while pulsating to a greater or lesser extent, the intake air passing through the surge tank 223 is also a kind of pulsating wave. The communication pipe 206 described above is connected to the intake pipe 204 on the downstream side of the surge tank 223.

  The impulse valve 224 and the communication pipe 206 constitute an example of an “intake system for an internal combustion engine” according to the present invention.

  An impulse valve 224 is provided between the intake pipe 204 and the communication pipe 206 on the downstream side of the surge tank 223. The impulse valve 224 is configured to be able to take a valve body position that selectively connects the intake pipe 204 and each communication pipe, and a valve body position that blocks communication between the intake pipe 204 and the communication pipe 206. The rotary valve is an example of the “intake control valve” according to the present invention.

  In the vicinity of the impulse valve 224, an actuator 225 that can provide the impulse valve 224 with the driving force used for the above-described change of the valve body position is installed. The actuator 225 includes a drive motor, a motor drive circuit, and a rotation angle sensor (all not shown).

  The drive motor is a DC brushless motor that is connected to the rotary shaft of the valve body of the impulse valve 224 and is provided with a permanent magnet, and includes a rotor (not shown) that is a rotor and a stator that is a stator. When the rotor is rotated by the action of a rotating magnetic field formed in the drive motor by energizing the stator via, a driving force is generated in the rotation direction.

  The motor drive circuit is a current control circuit including an inverter configured to be able to control a state of a magnetic field formed inside the drive motor through energization of the stator. The motor drive circuit is electrically connected to the ECU 100, and the operation of the motor drive circuit is controlled by the ECU 100. The drive motor is a DC brushless motor, and the drive voltage is a drive voltage Vdc, which is a DC voltage, but the drive current is generated by an inverter in the motor drive circuit in u-phase, v-phase, and w-phase. It is configured to be controlled as a corresponding three-phase alternating current.

  The rotation angle sensor is a so-called resolver configured to be able to detect the rotation angle of the rotor by utilizing the change of the phase of the voltage output from the two-phase coil of the rotor in the drive motor. As described above, the rotor is connected to the rotation shaft of the valve body of the impulse valve 224, and the rotor rotation angle detected by the rotation angle sensor is uniquely related to the opening degree of the impulse valve 224. The rotation angle sensor is electrically connected to the ECU 100, and the detected rotor rotation angle is grasped by the ECU 100 at a constant or indefinite cycle as an index value indicating the opening degree of the impulse valve 224. Yes. The means for detecting the opening degree of the impulse valve 224 is not limited to the resolver, and may be, for example, a hall sensor, a rotary encoder, or the like.

  In the engine system 10 according to the present embodiment, the engine 200 that is a gasoline engine is employed as an example of the “internal combustion engine” according to the present invention. However, the internal combustion engine according to the present invention refers only to the gasoline engine. Of course, a diesel engine, an engine using an alcohol mixed fuel, or the like may be used. Further, for the purpose of preventing the explanation from being complicated, the engine 200 according to the present embodiment is not equipped with an exhaust gas recirculation device such as an EGR device. It may be. Here, in view of the configuration in which the exhaust gas recirculation device is not mounted, in the engine 200 according to the present embodiment, the intake air sucked into each cylinder 202 through the intake port passes through the intake pipe 204 except for the fuel injected by the injector. It is comprised only by the intake air led through.

  The required load of the engine 200 is determined according to an accelerator opening degree Ta that is an operation amount (that is, an operation amount by a driver) of an accelerator pedal (not shown). The accelerator opening degree Ta is detected by the accelerator opening degree sensor 11 and is grasped at a constant or indefinite period by the ECU 100 electrically connected to the accelerator opening degree sensor 11. In general, the smaller the accelerator opening, the smaller the required load, and the larger the accelerator opening, the larger the required load. Since the magnitude of the required load correlates with the magnitude of the required output, in the engine system 10, the engine required output changes according to the accelerator opening degree Ta.

  Here, a detailed configuration around the impulse valve 224 will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view of the vicinity of the impulse valve 224 when viewed from the same direction as FIG. In the figure, parts that are the same as those in FIG.

  In FIG. 2, the impulse valve 224 includes a case 224A, a valve body 224B, and a rotating shaft 224C.

  The case 224A is a metal housing that houses the valve body 224B. In the wall portion of the case 224A, an opening is appropriately provided at a connection position with each communication pipe and a connection position with the intake pipe 204, and the valve body 224B, the intake pipe 204, and each of the connection positions with the intake pipe 204 are provided through the opening. The communication pipe communicates with the communication pipe.

  The valve body 224B is a metal member configured to be rotatable in the illustrated rotation direction around the rotation shaft 224C. A bent hollow communication portion 224B1 is formed in the valve body 224B, and the communication portion 224B1 rotates in the same direction as the valve body 224B rotates in the illustrated rotation direction. At this time, one end of the communication portion 224B1 is configured to always communicate with the intake pipe 204 via the opening on the intake pipe 204 side described above, and the other end is configured to rotate within the case 224A. It has become. FIG. 2 shows a state in which the communication portion 224B1 communicates with the communication pipe 2064 corresponding to the fourth cylinder through the opening on the fourth cylinder side provided in the case 224A.

The rotating shaft 224C is an example of a “predetermined axis” according to the present invention and an example of a “rotating axis defined along the axis” according to the present invention, which serves as a rotation center of the valve body 224B. The actuator 225 is connected to the rotor of the drive motor. In other words, in the present embodiment, as an example in which the “rotation axis” is defined along the “axis”, they overlap each other)
As for the communication pipe 2064, the opening facing the opening provided in the case 224A forms an opening 2064A as an example of the “second opening” according to the present invention, and the first cylinder and Similarly, the opening 2061A and the opening 2063A are defined for the third cylinder. The second cylinder is not shown because it corresponds to the back side in the figure, but an opening 2062A (not shown) is provided on the back side of the opening 2063A of the communication pipe 2063. That is, each of the openings formed in each communication pipe has a configuration arranged at equal intervals (here, 90 °) around the rotation shaft 224C of the valve body 224B. Further, as is apparent from the rotation direction shown in the drawing and the connection mode of each communication pipe to the impulse valve 224, each of the openings formed in each communication pipe is arranged in the order of the intake stroke. . In other words, the communication portion 224B1 of the valve body 224B communicates with each cylinder sequentially in the order of the fourth cylinder, the second cylinder, the first cylinder, and the third cylinder as the valve body 224B rotates with the illustrated position as a reference. It has a configuration.

  Here, the detailed configuration of the impulse valve 224 will be further described with reference to FIG. FIG. 3 is a schematic cross-sectional view taken along line A-A ′ in FIG. 2. In the figure, the same reference numerals are given to the same portions as those in FIG. 2, and the description thereof will be omitted as appropriate.

  In FIG. 3, the impulse valve 224 has a circular shape when viewed in cross section, and generally has a cylindrical shape. Therefore, the valve body 224B is also formed in a circular shape in a sectional view, and is configured to rotate in the rotation direction while sliding in the case 224A. Further, as shown in the figure, the communication pipes 2061, 2062, 2063, and 2064 communicating with each cylinder are configured to branch radially from the intake pipe 204 via the impulse valve 224. For this reason, in the engine 200, it is relatively easy to form the pipe lengths of the communication pipes 2061, 2062, 2063, and 2064 to a desired length. In this embodiment, the communication pipes 2061, 2062, 2063 are formed. And the pipe lengths of 2064 are substantially equal. Note that “substantially equal” will be described later.

  Here, the reference value of the position (hereinafter referred to as “impulse valve opening Aip” where appropriate) of the communicating portion 224B1 (see the thick broken line in the figure) of the valve body 224B corresponds to the state where the intake pipe 204 communicates with the fourth cylinder. In this case, the intake pipe 204 communicates with the second cylinder at Aip = 90 °, the first cylinder at Aip = 180 °, and the third cylinder at Aip = 270 °. On the other hand, at positions corresponding to Aip = 45 °, 135 °, 225 °, and 315 °, the communication portion 224B1 of the valve body 224B is in a shut-off state in which no cylinder is communicated.

<Operation of Embodiment>
Next, the operation of this embodiment will be described.

  First, the details of the basic drive control executed by the ECU 100 will be described with reference to FIG. FIG. 4 is a flowchart of basic drive control.

  In FIG. 4, the ECU 100 acquires the driving conditions of the vehicle (step S101). In the present embodiment, the engine speed Ne and the accelerator opening degree Ta are acquired as the operating conditions. When the engine rotation speed Ne and the accelerator opening degree Ta are acquired, it is determined whether or not the acquired operating condition corresponds to the inertial supercharging region (step S102).

  Here, the inertia supercharging region will be described with reference to FIG. FIG. 5 is a schematic diagram of the inertial supercharging region.

  In FIG. 5, the inertia supercharging region is a region corresponding to the hatched region shown in the two-dimensional coordinate system in which the accelerator opening degree Ta and the engine rotational speed Ne are arranged on the vertical axis and the horizontal axis, respectively. More specifically, it is assumed that the range of engine rotation speeds that can be taken by the engine 200 is not less than the minimum rotation speed NeL (which is the minimum rotation speed at which self-rotation is possible) and not more than the maximum rotation speed NeH (which is a so-called rev limit). When the accelerator opening degree Ta changes from 0% (ie, fully closed) to 100% (ie, fully open), the inertial supercharging region is NeL ≦ Ne ≦ Neth (Neth <NeH) and Tath ≦ Ta ≦. Qualitatively speaking, it is a low rotation and high load region. Although the load represented by the accelerator opening degree Ta is referred to here, the fuel injection amount or the like may be referred to as a vehicle operating condition instead of or in addition to the accelerator opening degree Ta.

  The minimum rotation speed NeL is a value of about 800 rpm, for example, and Neth is a determination reference value, for example, a value of about 2000 rpm. Further, Tath is a reference value for the accelerator opening, and is a value that can be used to determine that inertial supercharging is necessary in terms of required load. In other words, in the low load region less than the reference value Tath, it is not necessary to increase the intake charge amount from the beginning, so that it is not necessary to execute the inertia supercharging control.

  Returning to FIG. 4, when the acquired operating condition does not correspond to the inertial supercharging region (step S102: NO), the ECU 100 executes a non-inertial supercharging process (step S104). On the other hand, when the acquired operating condition corresponds to the inertial supercharging region (step S102: YES), the ECU 100 executes an inertial supercharging process (step S103). When the process according to step S103 or step S104 is executed, the process returns to step S101, and a series of processes is repeated.

  Here, the “inertia supercharging process” refers to a series of controls for generating intake air pulsation by controlling the opening degree of the impulse valve 224 and improving the charging efficiency of the intake air. .

  That is, for one cylinder 202 (for example, the first cylinder), before the start of the intake stroke (that is, preferably at the end of the intake stroke of another cylinder (for example, the second cylinder)) or at the beginning of the intake stroke When the communication between the cylinder and the intake pipe 204 is cut off (for example, when the actuator 225 is controlled so that the impulse valve opening degree Aip is 315 °), the communication with the intake pipe 204 is cut off. As the pressure decreases, the internal pressure of the communication pipe 206 (in the case of the first cylinder, the communication pipe 2061) becomes negative, and the pressure difference from the internal pressure of the intake pipe 204 that is maintained at or above atmospheric pressure by atmospheric pressure or supercharging. Expands. When the negative pressure is sufficiently formed in the communication pipe 206 as described above, the cylinder and the intake pipe 204 are communicated (for example, the actuator 225 is controlled so that the impulse valve opening degree Aip becomes 0 °). The intake pipe 204 and the inside of the corresponding cylinder 202 communicate with each other, and the intake air becomes the intake air at a stroke through the communication portion 224B1, the communication pipe 206 and the intake port formed in the valve body 224B of the impulse valve 224. Will flow into the combustion chamber.

  On the other hand, the intake port is a so-called open end at the site of communication with the combustion chamber, and the positive pressure wave caused by the inflow of intake air into the combustion chamber is reflected by the combustion chamber, so that the negative pressure wave whose phase is inverted is reflected. It becomes. The negative pressure wave reaches the surge tank 223 via the communication pipe 206 and the intake pipe 204 in order, and is reflected again as a positive pressure wave whose phase is inverted by reflection at the open end at the communication portion between the surge tank 223 and the intake pipe 204. To reach. When the peak of the positive pressure wave reaches the combustion chamber (or the intake valve 203) (not necessarily limited to that point in time, but includes that point as long as the charging efficiency of the intake can be improved to some extent). The opening of the impulse valve 224 may be adjusted so that this positive pressure wave reaches the combustion chamber by closing the intake valve 203 or at the timing when the intake valve 203 is closed. By controlling the switching timing, the pressure in the combustion chamber rises, and the intake charging efficiency is improved. Inertia supercharging using the impulse valve 224 is executed in this way.

  On the other hand, the “non-inertia supercharging process” is a process that does not perform such inertia supercharging, that is, normal drive control. In the non-inertia supercharging process, the impulse valve 224 is controlled according to the engine rotational speed Ne so that the valve body 224B rotates in synchronization with the start timing of the intake stroke of each cylinder. That is, when the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder are in the intake stroke, the actuator 225 is set so that the impulse valve solution Aip is 180 °, 270 °, 0 °, and 90 °, respectively. Be controlled.

  Here, the effect of this embodiment will be described with reference to FIGS. 2 and 3 again.

  According to this embodiment, the communication pipes 2061, 2062, 2063 and 2064 are selectively connected to the intake pipe 204 by the action of the impulse valve 224. That is, in the state where one cylinder communicates with the intake pipe 204, the communication between the other cylinders and the intake pipe 204 is blocked. For this reason, in the period of forming the negative pressure described above, the formation of the negative pressure is promoted very effectively, and a relatively large negative pressure can be formed. For this reason, the practical profit concerning the improvement of the filling amount or the filling efficiency of the intake air due to the inertia supercharging is great.

  For example, as a comparative example, the communication pipe 206 is shared by the cylinders (at least communication between the cylinders is not blocked if the opening and closing of the intake valve is ignored), and the communication state between the communication pipe and the intake pipe is used as an open / close valve. When control is performed according to the open / close state of the intake control valve, the volume of the communication pipe (dead volume) when the impulse valve is closed is clearly larger than that of the present embodiment. Therefore, the negative pressure formed during the closing period of the intake control valve is generally reduced, and the effect of improving the charging amount or the charging efficiency due to inertia supercharging is reduced. On the other hand, as another comparative example, when independent intake manifolds are installed from the surge tank to each cylinder, and intake control valves are installed on each intake manifold, various costs increase even though the formation of negative pressure is encouraged Cannot be avoided. In that respect, according to the single impulse valve 224 according to the present embodiment, it is possible to realize the same effect as the case where the intake control valve is individually provided for each cylinder at a low cost. There is a clear advantage over the comparative example.

  Further, according to the present embodiment, as described above, the individual communication pipes are radially branched from the intake pipe 204 via the impulse valve 224, and the pipe lengths between the individual communication pipes are set as follows. It is possible to adjust without worrying about the effect on installation and mounting. Here, as already described, in this embodiment, the pipe lengths of the individual communication pipes are substantially equal. For this reason, the inter-cylinder deviation of the intake air amount is suppressed to such an extent that it can be regarded as zero or zero, and it is preferable that the drivability decrease, the emission deterioration, and the fuel consumption deterioration due to the variation in the generated torque of the engine 200 be suitably achieved. It is suppressed.

  Here, “substantially equal” means that the individual communication pipes are within a range in which the deviation between the cylinders of the intake amount does not cause any trouble in practice or can be allowed to occur. This means that the pipe length is determined. Of course, the inter-cylinder deviation of the intake air amount is basically affected by the pipe length. From the viewpoint of suppressing the inter-cylinder deviation of the intake air amount, it is basically desirable to make the pipe lengths completely equal. Actually, when the allowable cylinder-to-cylinder deviation is assumed to be zero or as close to zero as possible, the allowable variation in the pipe length is always zero (that is, the pipe length is strictly equivalent). It is not limited, and it may have a finite range even if it is narrow. Within such a range, there is no substantial effect when the pipe length varies, and the pipe length should be made equal even more strictly even though the pipe length is within this range. Is irrelevant to the essential part of the invention.

  As described above, according to the engine 200 according to the present embodiment, by providing the impulse valve 224 and the communication pipe 206, it is possible to suitably generate a negative pressure and suppress an inter-cylinder deviation in the intake charge amount. Is possible.

  In addition, according to this embodiment, the structure of the impulse valve 224 and the connection mode of the communication pipe 206 enjoy the benefit of expanding the inertial supercharging region in addition to the benefits described above. As described above, the communication pipes 2061, 2062, 2063, and 2064 are arranged in the order of the intake stroke around the axis, and the impulse valve for switching the target cylinder for inertia supercharging in the above-described inertia supercharging process. The amount of change in the opening is 90 °.

  On the other hand, in the case of one communication pipe, there is no change in the state when the impulse valve opening degree Aip takes a value other than the value that allows the intake pipe 204 to communicate with itself. Specifically, taking the first cylinder as an example, when the negative pressure is formed in the communication pipe 2061, the impulse valve solution Aip is in a predetermined range centered on 180 ° (the communication portion 224B1 of the valve body 224B and the communication pipe 2061). It is only necessary to be outside the range in which the opening 2061A overlaps.

  For this reason, the impulse valve opening Aip is advanced to some extent (advanced in this case) during the period from when the intake valve 207 of the second cylinder is closed until the first cylinder, which is the next cylinder, is communicated with the intake pipe 204. An angle can simply be advanced in the direction of rotation). More specifically, as described above, when the impulse valve opening Aip is 45 °, 135 °, 225 °, and 315 °, none of the cylinders is used for communication with the intake pipe 204. When the target cylinder for inertia supercharging is switched from the second cylinder to the first cylinder, the valve body 224B of the impulse valve 224 may be advanced to a position corresponding to Aip = 135 ° as a preparation stage. For this reason, the drive range at one operation timing of the impulse valve 224 is substantially 45 °.

  When the comparative example described above is considered again, it is clear that if the impulse valve is opened to some extent, the formation of the negative pressure downstream of the impulse valve is inhibited, and the impulse valve is advanced 90 ° at a time. It is necessary to horn. Therefore, if the performance of the actuator is equivalent, the impulse valve 224 according to the present embodiment has an operation speed twice that of the comparative example (of course, when the opening degree and the time are linear), and at least some It is obvious that the response time is quite short. In turn, the upper limit defined by the engine rotation speed in the inertial supercharging region illustrated in FIG. 5 becomes difficult to make the response speed of the impulse valve 224 follow the engine rotation as the engine rotation speed increases. In view of the fact that the response speed can be improved in this way, the configuration of the impulse valve 224 and the communication pipe 206 according to the present embodiment increases the inertia supercharging region. It is also possible to plan easily.

  The present invention is not limited to the above-described embodiments, and can be changed as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. The system is also included in the technical scope of the present invention.

1 is a schematic configuration diagram conceptually showing a configuration of an engine system according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view in the vicinity of an impulse valve in the engine system of FIG. 1. It is typical A-A 'line sectional drawing in FIG. 2 is a flowchart of basic drive control executed in the engine system in FIG. 1. It is a schematic diagram of the inertia supercharging area | region referred in the basic drive control of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine system, 100 ... ECU, 200 ... Engine, 202 ... Cylinder, 204 ... Intake pipe, 205 ... Throttle valve, 206, 2061, 2062, 2063, 2064 ... Communication pipe, 207 ... Intake valve, 216 ... Turbine, 218 Compressor, 222, intercooler, 223, surge tank, 224, impulse valve, 224B, valve body, 224B1, communication portion, 225, actuator.

Claims (4)

An intake system for an internal combustion engine that is mounted on a vehicle and includes a plurality of cylinders and a shared intake passage shared between the plurality of cylinders,
Each is configured as a conduit having a first opening and a second opening, and is configured to be able to communicate with each of the plurality of cylinders in the first opening, and the second opening A plurality of first intake passages each arranged around a predetermined axis;
A valve body rotatable around a rotation axis defined along the axis, and the second opening in one of the shared intake passage and the first intake passage in a process of rotating the valve body; An intake system for an internal combustion engine, comprising: an intake control valve that can be selectively connected to the engine. The intake system for an internal combustion engine according to claim 1, wherein the second openings are arranged around the axis in the order in which an intake stroke is performed. The intake system for an internal combustion engine according to claim 1 or 2, wherein the second openings are arranged at equal intervals around the axis. The intake system for an internal combustion engine according to any one of claims 1 to 4, wherein the first intake passage is configured so that a pipe length is substantially equal for each of the first intake passages. .

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