JP2007016693A - Intake air flow control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake air flow control device for an internal combustion engine, capable of intensifying an air flow during low load without producing intake resistance during high load. <P>SOLUTION: The intake air flow control device comprises an intake valve 20 having a ridge portion 20R formed over the almost half periphery of the reverse face of an umbrella portion 20K, a variable lift amount valve train 120 for changing the valve lift amount of the intake valve 20, and a control means for controlling the variable lift amount valve train depending on an operated condition. Besides, it has a rotation positioning mechanism 110 for the intake valve 20. The control means controls the rotation positioning mechanism 110 together with the variable lift amount valve train 120 depending on the operated condition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an intake flow control device for an internal combustion engine.

  Conventionally, in order to improve combustion in an internal combustion engine, various intake flow control devices that generate air flow in a cylinder have been proposed. For example, Patent Document 1 discloses a technique in which an arc-shaped shroud is provided on a part of the rear surface of the umbrella portion of the intake valve, and the swirl strength is changed by changing the position of the shroud. Further, Patent Document 2 includes a rectifying plate that can rotate around the intake valve across the opening between the intake valve and the wall surface of the intake port, and by rotating the rectifying plate according to the operating state, A technique is disclosed in which a forward or reverse tumble or swirl is generated in the flow.

Japanese Utility Model Publication No. 63-183404 Japanese Patent Laid-Open No. 10-331647

  By the way, in general, in an internal combustion engine, by using the above-mentioned shroud, a rectifying plate, etc., a strong air flow is forcibly generated in the cylinder (hereinafter, this is referred to as airflow enhancement). Improvement is desired at low loads where the intake flow rate is low, and it is preferable that these do not become intake resistances at high loads where improvement in charging efficiency is desired.

  However, with the technique described in Patent Document 1, it is possible to generate a weak swirl at a low load due to the drifting action by the shroud, but it is difficult to perform airflow reinforcement or tumble.

  Further, in the technique described in Patent Document 2, it is possible to cause reverse tumble by rotating the rectifying plate to a position intersecting the intake flow direction during low load stratified combustion operation. It is difficult to strengthen the airflow at the location.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an intake air flow control device for an internal combustion engine that can enhance airflow at low load regardless of forward or reverse tumble or swirl and does not become intake resistance at high load. Is to provide.

  An intake flow control device for an internal combustion engine according to an embodiment of the present invention that achieves the above-described object is provided with an intake valve in which a raised portion is formed over almost a half of the back surface of the umbrella, and the valve lift amount of the intake valve can be changed. A variable lift amount valve mechanism and a control means for controlling the variable lift amount valve mechanism in accordance with an operating state are provided.

  Here, the intake valve may further include a rotation positioning mechanism, and the control means may control the rotation positioning mechanism together with the variable lift amount valve mechanism according to an operating state.

  According to the intake flow control device for an internal combustion engine according to one aspect of the present invention, the variable lift amount valve mechanism is controlled by the control means according to the operating state, and the lift amount of the intake valve is changed according to this control. It will be. Then, when the lift amount of the intake valve is small, almost half of the opening of the intake port is blocked by the raised portion formed over almost half of the back of the umbrella. The airflow is strengthened by passing between the part having no raised part on the back surface and sucked into the cylinder. On the other hand, when the lift amount of the intake valve is large, since the entire umbrella portion including the raised portion exceeds the opening portion of the intake port, intake air is sucked into the cylinder without any intake resistance.

  Here, the rotation positioning mechanism of the intake valve is further provided, and the control means controls the rotation positioning mechanism together with the variable lift amount valve mechanism according to the operation state. The rotational positioning mechanism of the intake valve is also controlled. Therefore, when the lift amount of the intake valve is small, by positioning the rotation position of the intake valve at a predetermined position, the remaining opening portion of the intake port that is not blocked and the portion without the raised portion on the back of the umbrella portion Since the direction of the flow path formed between them is directed to the direction in which the forward or reverse tumble or swirl is generated, the airflow can be enhanced at low load regardless of the forward or reverse tumble or swirl.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

  1 is a longitudinal sectional view (II cross section in FIG. 2) of a gasoline engine (hereinafter referred to as “engine”) 10 as an internal combustion engine to which the above-described invention is applied, and FIG. 2 is II-II in FIG. A cross-sectional view is shown.

  The engine 10 is mounted on an automobile for use in an automobile. The engine 10 includes a cylinder block 12, a piston 14 that reciprocates within the cylinder block 12, a cylinder head 16 attached on the cylinder block 12, and the like. For example, four cylinders 10 a are formed in the cylinder block 12, and a combustion chamber 18 defined by the cylinder block 12, the piston 14, and the cylinder head 16 is formed in each cylinder 10 a.

  In each combustion chamber 18, an intake valve 20 (first intake valve 20a, second intake valve 20b) and an exhaust valve 24 (first exhaust valve 24a and second exhaust valve 24b) are arranged. Among these, the first intake valve 20a opens and closes the first intake port 22a, the second intake valve 20b opens and closes the second intake port 22b, the first exhaust valve 24a opens and closes the first exhaust port 26a, and the second The exhaust valve 24b is disposed so as to open and close the second exhaust port 26b (see FIG. 2). In the following description, when there is no need to distinguish between the first and second intake valves, exhaust valves, intake ports, and exhaust ports, the subscripts are omitted.

  Further, the cylinder head 16 is provided with a spray guide type fuel injector 30 and a spark plug 32 adjacent to each other in the form desired at the top of each combustion chamber 18, so that a necessary amount of fuel is supplied to the cylinder 10a. Injectable.

  Both the first intake port 22a and the second intake port 22b of each cylinder 10a are connected to a surge tank (not shown) via an intake passage formed in the intake manifold. The surge tank is connected to an air cleaner via an intake duct. In this embodiment, a throttle valve (not shown) that is driven by an electric motor independently of the operation of the accelerator pedal is arranged in the intake duct. ing. Further, the adjustment of the lift amount of the first intake valve 20a and the second intake valve 20b includes an intermediary drive mechanism (described later) existing between the intake cam 45a provided on the intake cam shaft 45 and the rocker arm 13. This is performed by the variable lift valve mechanism 120.

  The first exhaust valve 24a that opens and closes the first exhaust port 26a of each cylinder 10a and the second exhaust valve 24b that opens and closes the second exhaust port 26b are connected to the exhaust camshaft 46 as the engine 10 rotates. The exhaust cam 46a is provided so as to be opened and closed with a certain lift amount through the rocker arm 15 by rotation of the exhaust cam 46a. The first exhaust port 26a and the second exhaust port 26b of each cylinder 10a are communicated with an exhaust pipe through an exhaust manifold, and a three-way catalytic converter (not shown) is disposed in the exhaust pipe.

  Here, the structure of the intake valve 20 (the first intake valve 20a and the second intake valve 20b) will be described with reference to FIG. 3 (A) and 3 (B) each show a single intake valve 20, and FIG. 3 (C) shows a state where the intake valve 20 is incorporated in the engine 10 and is in the state of a small lift amount. It is shown. The intake valve 20 according to the present embodiment is a poppet valve type, and a raised portion 20R is formed on the back surface of the umbrella portion 20K continuous to the tip of the stem portion 20S over almost a half circumference. And the part without this protruding part 20R forms the smooth slope surface 20F from the stem part 20S to the periphery of the umbrella part 20K. That is, the raised portion 20R closes substantially half the circumference of the opening 22X of the intake port 22 in the small lift amount state of the intake valve 20 shown in FIG. 3C, in other words, the intake air located on one side of the intake valve 20 Only the remaining portion of the opening 22X of the port 22 is formed to be opened. Therefore, when the intake valve 20 is in a small lift amount state, substantially half of the opening 22X of the intake port 22 is closed by the raised portion 20R formed over almost half of the back surface of the umbrella portion 20K. The intake air passes between the remaining opening 22X where the intake port 22 is not blocked and the portion of the slope surface 20F where the rear surface of the umbrella portion 20K does not have a raised portion, and the airflow is strengthened to make a cylinder (cylinder). 10a is inhaled.

  Further, in the first embodiment of the intake valve 20 shown in FIG. 3A, a projection 20P is formed on the stem portion 20S, and the guide groove 16G formed on the cylinder head 16 is formed in the guide head 16G as shown in FIG. It is slidably fitted. Thus, the intake valve 20 is not allowed to rotate.

  Further, in the second embodiment of the intake valve 20 shown in FIG. 3B, the worm wheel teeth 20W are formed on the stem portion 20S, and are driven by the motor M arranged on the cylinder head 16 as shown in FIG. The worm teeth Wt are engaged. These motor M, worm tooth Wt and worm wheel tooth 20W constitute a rotational positioning mechanism 110 of the intake valve 20 according to the present invention. The rotation positioning mechanism may be a mechanism that rotates the intake valve 20 with a rack formed with a pinion in the stem portion 20S and driven by an actuator.

  An electronic control unit (hereinafter referred to as ECU) 100 is composed of a digital computer, and is connected to each other via a bidirectional bus such as RAM (random access memory), ROM (read only memory), CPU (microprocessor), An input port and an output port are provided.

  An accelerator opening sensor 76 is attached to the accelerator pedal 74, and an output voltage proportional to the amount of depression of the accelerator pedal 74 is input to the input port via the AD converter. A top dead center sensor (not shown) generates an output pulse when, for example, the first cylinder of the cylinders 10a reaches the intake top dead center, and this output pulse is input to the input port. A crank angle sensor (not shown) generates an output pulse every time the crankshaft rotates 30 °, and this output pulse is input to the input port. The CPU calculates the current crank angle from the output pulse of the top dead center sensor and the output pulse of the crank angle sensor, and calculates the engine speed from the frequency of the output pulses of the crank angle sensor.

  An intake air amount sensor (not shown) is provided in the intake duct, and an output voltage corresponding to the intake air amount flowing through the intake duct is input to the input port via the AD converter 73. In addition, a water temperature sensor (not shown) is provided in the cylinder block 12 of the engine 10 to detect the cooling water temperature of the engine 10 and input an output voltage corresponding to the cooling water temperature to the input port via the AD converter. Yes.

  Furthermore, output pulses from a shaft position sensor that detects the axial displacement of the control shaft 132 that is moved by a lift amount variable actuator, which will be described later, and a cam angle sensor that detects the cam angle of the intake cam 45a are input to the input port. The In addition to this, various signals are input to the input port, but they are not shown in the present embodiment because they are not important in the description.

  The output port is connected to each fuel injector 30 and spark plug 32 via a corresponding drive circuit, and the ECU 100 performs valve opening control of each fuel injector 30 in accordance with the operating state of the engine 10, and the fuel injection timing. Control, fuel injection amount control, and ignition timing control of the spark plug 32 are executed. Further, the output port is connected to a first oil control valve (not shown) via a drive circuit, and the ECU 100 controls the variable lift amount actuator in accordance with the operating state of the engine 10 such as the required intake air amount. Further, the output port is connected to a second oil control valve (not shown) via a drive circuit, and the ECU 100 controls the rotational phase difference variable actuator according to the operating state of the engine 10. As a result, the lift amount and valve timing of the intake valve 20 are controlled by the ECU 100, and intake air amount control and other controls are executed.

  Here, the variable lift valve mechanism 120 of the intake valves 20a, 12b will be described with reference to FIGS. The variable lift amount valve mechanism 120 is provided for each cylinder 10 a and includes a lift amount variable actuator (not shown) attached to one end of the cylinder head 16. The variable lift valve mechanism 120 includes an input portion 122 provided at the center, a first swing cam 124 provided on the left, and a second swing cam 126 provided on the right. The housing 122a of the input part 122 and the housings 124a and 126a of the swing cams 124 and 126 have a cylindrical shape with the same outer diameter. The input portion 122 is provided with a roller 122d that is supported by arms 122b and 122c protruding from the outer periphery of the input portion 122 and engages with the intake cam 45a. Further, a nose 124b and a nose 126b that are engaged with the roller 13a of the rocker arm 13 project from the outer periphery of the first rocking cam 124 and the second rocking cam 126.

  Further, a right-handed helical spline is formed on the inner peripheral part of the input part 122, and a left-handed helical spline is formed on the inner peripheral parts of the first swing cam 124 and the second swing cam 126, respectively. . The right-hand input helical spline that meshes with the helical spline of the input unit 122, and the left-screw output helical spline that meshes with the helical splines of the first swing cam 124 and the second swing cam 126, respectively. The formed slider gear (not shown) is provided inside the input unit 122, the first swing cam 124, and the second swing cam 126. The slider gear has a through hole through which the support pipe 130 is inserted, and a control shaft 132 is slidably inserted into the support pipe 130. The control shaft 132 is provided with a locking pin that passes through a long hole formed in the support pipe 130 in the axial direction and engages with a long hole formed in the slider gear in the circumferential direction. Thus, by adjusting the displacement of the control shaft 132 in the axial direction with respect to the support pipe 130 fixed to the cylinder head 16 by the lift amount variable actuator (not shown), the amount of movement of the slider gear in the axial direction can be reduced. Adjusted. Then, by adjusting the amount of movement of the slider gear in the axial direction, the phase difference between the input portion 122, the first swing cam 124, and the second swing cam 126, which are respectively connected via the helical spline, is adjusted. Thus, the lift amount of the intake valve 20 is changed. For the detailed structure of the variable lift valve operating mechanism 120, reference can be made to Japanese Patent Laid-Open Nos. 2001-263015 and 2004-92500.

  The opening / closing timing of the intake valve 20 can be changed by adjusting the intake valve timing variable valve mechanism that can arbitrarily control the rotation phase of the intake camshaft 45 relative to the crankshaft with a variable rotation phase difference actuator. Is done. Since the structure of the intake valve timing variable valve mechanism is well known, detailed description thereof is omitted.

  Next, an example of the valve drive control process of the intake air flow control device for the internal combustion engine according to the present invention will be described with reference to the flowchart of FIG. This process is repeatedly executed every period. Therefore, when the valve drive control process is started, the engine operating state is detected in step S501. In the present embodiment, the accelerator opening representing the required load obtained based on the signal from the accelerator opening sensor 76, the intake air amount representing the load obtained based on the signal from the intake air amount sensor, and the crank angle sensor. The operating state of the engine is detected based on the engine speed obtained based on the signal. Then, in the next step S502, the lift amount of the intake valve 20 is determined based on the intake valve optimum lift amount value obtained in advance through experiments or the like and stored in the map in correspondence with the detected engine operating state. It is determined. Specifically, the amount of axial displacement of the control shaft 132 by the variable lift amount actuator is determined.

  Various modes in which the intake valve 20 is driven with the determined lift amount are shown in FIGS.

  FIG. 6 shows a mode in which a forward tumble is obtained using the intake valve 20 of the form shown in FIG. 3A as the intake valve, FIG. 6A shows a low load of the engine, and FIG. The high load is shown. As the lift amount of the intake valve 20 is small when the engine 10 is under a low load, the ridge 20R formed over almost half the circumference of the back of the umbrella portion of the intake valve 20 results in the almost half circumference of the opening 22X of the intake port 22 being blocked. The intake air passes between the remaining opening portion 22X of the intake port 22 and the portion without the raised portion on the back surface of the umbrella portion, so that a forward tumble with airflow enhancement as shown by an arrow T can be obtained. . On the other hand, when the load is high as shown in FIG. 6B, the lift amount of the intake valve 20 is large, and the entire umbrella portion 20K including the raised portion 20R exceeds the opening portion 22X of the intake port 22; Is sucked into the cylinder.

  FIG. 7 shows a mode in which a swirl is obtained by using the intake valve 20 of the form shown in FIG. 3A as the intake valve. FIG. 7A is a side sectional view when the engine is under low load, and FIG. ) Is a perspective view as seen from an arrow A in FIG. 7A, and FIG. 7C is a perspective view seen from above the cylinder. In the case of obtaining this swirl, the position of the guide groove 16G in which the protrusion 20P formed on the stem portion 20S of the intake valve 20 is slidably fitted is rotated by 90 ° compared to the case of FIG. The cylinder head 16 is formed at the position. In the case of this aspect, similarly, since the lift amount of the intake valve 20 is small when the engine 10 is under a low load, the opening of the intake port 22 is formed by the raised portion 20R formed over almost the half circumference of the rear surface of the umbrella portion of the intake valve 20. As a result, the intake air passes between the remaining opening 22X of the intake port 22 and the portion without the raised portion on the back surface of the umbrella portion, and as a result, the air flow enhancement as indicated by the arrow S is performed. You can get the swirl done. On the other hand, when the load is high, although not shown, the lift amount of the intake valve 20 is large, and the entire umbrella portion 20K including the raised portion 20R exceeds the opening portion 22X of the intake port 22, so that intake air is not generated without intake resistance. Is sucked into the cylinder.

  Further, FIG. 8 is a side sectional view of the position of the intake valve 20 when the engine is under a low load, showing a mode in which reverse tumble is obtained using the intake valve 20 of the form shown in FIG. 3A as the intake valve. In the case of obtaining this reverse tumble, the position of the above-mentioned guide groove 16G into which the projection 20P formed on the stem portion 20S of the intake valve 20 is slidably fitted is 90 in comparison with the case of FIG. Formed on the cylinder head 16 at a rotated position. In the case of this aspect, similarly, since the lift amount of the intake valve 20 is small when the engine 10 is under a low load, the opening of the intake port 22 is formed by the raised portion 20R formed over almost the half circumference of the rear surface of the umbrella portion of the intake valve 20. As a result, the intake air passes between the remaining opening 22X of the intake port 22 and the portion without the raised portion on the back surface of the umbrella portion, and as a result, the air flow enhancement as indicated by the arrow RT is performed. The performed reverse tumble can be obtained. On the other hand, when the load is high, although not shown, the lift amount of the intake valve 20 is large, and the entire umbrella portion 20K including the raised portion 20R exceeds the opening portion 22X of the intake port 22, so that intake air is not generated without intake resistance. Is sucked into the cylinder.

  Next, another example of the valve drive control process of the intake air flow control device for the internal combustion engine according to the present invention will be described with reference to the flowchart of FIG. This process is also repeatedly executed every cycle. Therefore, when another example of the valve drive control process is started, the operating state of the engine is detected in step S901 as in the previous embodiment. In the next step S902, the lift amount of the intake valve 20 is determined based on the intake valve optimum lift amount value obtained in advance through experiments or the like and stored in the map in correspondence with the detected engine operating state. It is determined. Then, the process further proceeds to step S903, and the rotational position of the intake valve 20 is determined based on the intake valve optimum rotational position value obtained in advance by experiments or the like and stored in the map in correspondence with the detected engine operating state. Is determined. Specifically, the rotation amount of the intake valve 20 by the motor M of the rotational positioning mechanism is determined.

  As the intake valve optimum rotation position, it is possible to set the optimum rotation position in accordance with the operating state as in the above-described mode positions shown in FIGS. For example, in the present embodiment, tumble and swirl are selectively generated in the cylinder corresponding to the operating state. Specifically, when the load is light and low, the intake valve 20 is rotated to the position shown in FIG. 7 in a state where the lift amount is small, thereby generating a swirl with enhanced airflow in the cylinder and stratified combustion. To do. When the load is larger than the light and light load, the intake valve 20 is rotated to the position shown in FIG. 6 or FIG. 8 while the lift amount is small, thereby enhancing the airflow in the cylinder. The generated forward tumble or reverse tumble is generated to perform homogeneous lean combustion.

  Thus, according to the present embodiment, by controlling the lift amount and the rotational position of the intake valve 20 in accordance with the operating state, it is possible to generate a desired mode of airflow with a desired strength, It can greatly contribute to improvement of combustion.

It is sectional drawing which shows the engine in embodiment of this invention. It is II-II sectional drawing in FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is drawing explaining the intake valve which concerns on this invention, (A) is 1st Embodiment of an intake valve, (B) is a side view which each shows 2nd Embodiment of an intake valve, (C) is an intake valve, an engine is an engine. It is sectional drawing which shows the state integrated in. It is a top view which shows a one part component of the variable lift amount valve mechanism in embodiment of this invention. It is a flowchart which shows an example of the valve drive control processing of the intake air flow control apparatus of the internal combustion engine which concerns on this invention. The aspect which obtains a forward tumble using the intake valve of 1st Embodiment as an intake valve is shown, (A) has shown at the time of low load of an engine, and (B) has shown at the time of high load. The aspect which obtains a swirl similarly using the intake valve of 1st Embodiment as an intake valve is shown, (A) is a sectional side view in the time of low load of an engine, (B) is an A arrow view of (A), (C ) Is a perspective view seen from above the cylinder. FIG. 5 is a side sectional view of the intake valve position when the engine is under a low load, showing a mode in which reverse tumble is obtained using the intake valve 20 of the form shown in the first embodiment as the intake valve. It is a flowchart which shows the other example of the valve drive control processing of the intake air flow control apparatus of the internal combustion engine which concerns on this invention.

Explanation of symbols

10 Engine 10a Cylinder
DESCRIPTION OF SYMBOLS 20 Intake valve 20K Umbrella part 20S Stem part 20R Raised part 20F Slope surface 20W Warm wheel tooth 22 Intake port 22X Open part 30 Fuel injector 32 Spark plug 100 Electronic control unit 110 Rotation positioning mechanism Wt Warm tooth M Motor 120 Variable lift amount valve Mechanism 122 Input section 124 First swing cam 126 Second swing cam

Claims (2)

An intake valve in which a raised portion is formed over almost half of the back of the umbrella,
A variable lift valve operating mechanism capable of changing the valve lift amount of the intake valve;
An intake flow control device for an internal combustion engine, comprising: control means for controlling the variable lift valve operating mechanism in accordance with an operating state. 2. The internal combustion engine according to claim 1, further comprising a rotation positioning mechanism of the intake valve, wherein the control unit controls the rotation positioning mechanism together with the variable lift amount valve mechanism according to an operating state. Intake flow control device.

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