JP2010196594A - Ventilation device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ventilation device for an internal combustion engine which is compact and low cost and includes a PCV valve, and to enable detection that a valve element member is stuck. <P>SOLUTION: The ventilation device for the internal combustion engine in which the PCV valve 50 comprises a case 51, a valve element member 52 and a compression coil spring 53, includes an electromagnetic coil 55 energizing a valve element member 52 in a close or an open direction, a pressure difference detection means 61 detecting pressure difference, an excitation drive means 62 selectively supplying current to the electromagnetic coil 55 exciting and driving the electromagnetic coil 55 under a condition where detected pressure difference reaches pressure difference level capable of moving the valve element member 52, and a movable condition determination means 63 determining whether a movable state of the valve element member 52 is normal or not, based on induced current induced at the electromagnetic coil 55 by movement of the valve element member 52 when pressure difference detected by the pressure difference detection means 61 reaches pressure difference level capable of moving the valve element member 52 and the electromagnetic coil 55 is not under excited state. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a ventilation device for an internal combustion engine, and more particularly to a ventilation device for an internal combustion engine having a PCV valve that allows recirculation of blow-by gas from the inside of the engine body to the inside of an intake pipe and restricts the reverse flow.

  In internal combustion engines mounted on automobiles, etc., blow-by gas leaks from the combustion chamber through the gap between the cylinder and the piston into the crankcase, so the crankcase is used to prevent engine oil deterioration and corrosion. It is equipped with a PCV (Positive Crankcase Ventilation) type ventilation device (also called blow-by gas reduction device) that forcibly ventilates the interior. Further, in such a ventilation device for an internal combustion engine, a PCV valve having a check valve function for permitting recirculation of blowby gas from the inside of the engine body to the inside of the intake pipe and restricting the flow in the reverse direction is used. Yes.

  As a conventional ventilation device for this type of internal combustion engine, a valve body is connected to a plunger driven by an electromagnetic coil so that the position of the valve body can be controlled based on the output of the rotational speed sensor of the internal combustion engine. An electronic control PCV valve is known (for example, see Patent Document 1).

  Further, two blow-by gas recirculation passages are provided between the inside of the engine body of the internal combustion engine and the intake passage, and an electromagnetic on-off valve and an orifice are provided on one of the passages, so that the intake passage for blow-by gas during the warm-up operation is provided. An electromagnetic on-off valve of this apparatus is known in which a push rod that protrudes toward a valve body is attached to a plunger driven by an electromagnetic coil. When the cold state is detected, the valve body is urged in the valve opening direction (see, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 08-338222 JP-A-61-187907

  However, in a conventional internal combustion engine ventilation device in which a valve body is connected to a plunger driven by an electromagnetic coil, current is supplied to the electromagnetic coil in the entire rotation range of the internal combustion engine, and the electromagnetic driving force is constantly adjusted. Therefore, there is a problem that it is difficult to obtain a compact and low-cost PCV valve because an electromagnetic drive means having a large output is required.

  Further, even in an internal combustion engine ventilation device in which two blow-by gas recirculation passages are provided between the inside of the engine body of the internal combustion engine and the intake passage, the plunger driven by the electromagnetic coil and the valve body member are separated. Since it is provided, it is necessary to use a return spring of the plunger, etc., so that an electromagnetic drive means having a large output is necessary, and there is a problem that it is difficult to achieve a compact and low-cost configuration.

  Furthermore, in any of the above-described devices, there is a problem that when the valve body member is in a fixed state, such a failure state cannot be detected promptly and accurately even though the PCV valve cannot operate normally. there were.

  The present invention has been made to solve the above-described conventional problems, and provides a compact and low-cost internal combustion engine ventilation apparatus having a PCV valve, and also detects sticking of the valve body member. The purpose is to make it possible.

  In order to achieve the above object, the PCV valve according to the present invention is interposed between the engine body of the internal combustion engine and the intake pipe, and allows the blow-by gas generated inside the engine body to flow back into the intake pipe. A PCV valve that can be interposed between the engine main body and the intake pipe to form a part of a return passage for the blow-by gas from the engine main body to the intake pipe. In a valve closing direction approaching the valve seat portion and in a valve opening direction away from the valve seat portion according to a differential pressure between the inside of the engine body and the inside of the intake pipe. A valve body member movably accommodated in the case to move, and an elastic member interposed between the case and the valve body member to urge the valve body member in the valve closing direction, Of an internal combustion engine comprising In the chilling device, an electromagnetic coil that can generate an electromagnetic force that urges the valve body member in at least one of the valve closing direction and the valve opening direction, and a differential pressure detecting unit that detects the differential pressure; In the state where the differential pressure detected by the differential pressure detecting means has reached a differential pressure level at which the valve body member can be moved, a current for exciting and driving the electromagnetic coil is selectively supplied to the electromagnetic coil. When the differential pressure detected by the differential drive detection means and the differential pressure detection means reaches a differential pressure level at which the valve body member can be moved, and the electromagnetic coil is in a non-excitation state, the valve body member And a movable state determining means for determining whether or not the movable state of the valve body member is normal based on an induced current generated in the electromagnetic coil by the movement of.

  With this configuration, when the valve body member responds to the differential pressure, the movement of the valve body member is assisted or suppressed by the excitation drive of the electromagnetic coil, and the current for exciting the electromagnetic coil is selected for the electromagnetic coil. The normal flow characteristics of the PCV valve that responds to the differential pressure when the electromagnetic coil is not excited, and the higher or lower differential pressure than the normal flow characteristics when the electromagnetic coil is excited. The flow rate can be switched to another flow characteristic that shifts, and since the high-power electromagnetic drive means is not required as in the case where the valve body is driven only by the electromagnetic coil, the PCV valve is compact and low-cost. Can be.

  Further, by switching the direction of the current for exciting and driving the electromagnetic coil, the flow rate characteristic different from the normal flow rate characteristic of the PCV valve is shifted to the increasing side of the differential pressure from the normal characteristic. It is also possible to switch to a flow rate characteristic that shifts to a lower side, and the flow rate characteristic of the PCV valve can be switched in three stages.

  Further, when the differential pressure reaches a differential pressure level at which the valve body member can be moved and the electromagnetic coil is in a non-excited state, the movable state determining means causes the movement of the valve body member that responds to the differential pressure to the electromagnetic coil. Since whether or not the movable state of the valve body member is normal is determined based on whether or not the induced current to be generated is detected, the PCV valve can be securely detected.

  In addition, since the movable state determination means uses an electromagnetic coil and differential pressure detection means used for switching the flow characteristics of the PCV valve, it can be realized with a simple configuration and mounted on an in-vehicle ECU (electronic control unit). It can be easily incorporated into an on-board failure diagnosis circuit.

  According to the present invention, by selectively supplying an excitation drive current to the electromagnetic coil, the flow rate characteristic of the PCV valve that responds to the differential pressure is changed to a flow rate characteristic suitable for the operating state of the internal combustion engine. It is possible to switch between the flow characteristics under the non-excited state and the flow characteristics under the excited state. Moreover, unlike the case where the valve body is driven only by the electromagnetic coil, no large output electromagnetic drive means is required, and PCV It is possible to provide a ventilation device for an internal combustion engine, which can make the valve compact and low-cost.

  Further, whether or not the movable state of the valve body member is normal is determined by using the differential pressure generation information and the detection information of the induced current that should be generated in the electromagnetic coil at that time. The state can be reliably detected.

1 is a schematic configuration diagram of a PCV valve that is a main part of a ventilation device for an internal combustion engine according to an embodiment of the present invention and a control system thereof. It is sectional drawing which shows schematic structure of the internal combustion engine equipped with the ventilation apparatus of the internal combustion engine which concerns on one Embodiment of this invention. It is a graph which shows the flow characteristic of the PCV valve in the ventilation apparatus of the internal combustion engine which concerns on one Embodiment of this invention, A vertical axis | shaft is a flow volume and a horizontal axis is the differential pressure before and behind a PCV valve.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 and FIG. 2 are views showing a ventilation device for an internal combustion engine according to an embodiment of the present invention. The present invention is applied to an internal combustion engine for a vehicle, for example, a four-cycle gasoline engine (hereinafter simply referred to as an engine). The case where it applies is illustrated.

  First, the configuration will be described.

  As shown in FIG. 2, the engine 1 equipped with the ventilation device of the present embodiment includes an engine body 10 having a head cover 11, a cylinder head 12, a cylinder block 13 and a crankcase 14. A plurality of cylinders 15 are formed by a plurality of cylinders 13 a (only one is shown in FIG. 2) of the block 13.

  A piston 16 is accommodated in each cylinder 15, and a crankshaft 17 in the crankcase 14 is connected to the piston 16 via a connecting rod 18. Also, a known valve operating mechanism 20, an ignition device 23, an injector 24, and the like are housed in the cylinder head 12, and the valve operating mechanism 20 is interlocked with the crankshaft 17 based on power (or with the crankshaft 17). To be driven independently).

  An oil pan 19 is provided at the lower part of the crankcase 14, and contains engine oil for lubrication and cooling (hereinafter also simply referred to as oil) (not shown). Although not shown, the engine 1 is provided with an oil pump that is driven based on the power of the crankshaft 17. The oil pump pumps oil out of the oil pan 19, and the camshaft 21 of the valve mechanism 20. , 22 or the like, or each rotating / sliding portion such as a bearing portion of the crankshaft 17 is lubricated and cooled.

  Air is sucked into the combustion chamber 1a formed in the upper part of the piston 16 in each cylinder 15 through the intake passage 31 and the intake port 1b according to the stroke of the piston 16, and exhausted after combustion in the combustion chamber 1a. The gas is exhausted through the exhaust port 1c and an exhaust passage (not shown).

  Here, the intake passage 31 includes a throttle body 33 that accommodates the throttle valve 32 so as to be pivotable (open / close operation), and an upstream intake pipe provided on the upstream side and the downstream side of the throttle body 33, respectively. 34 and a downstream intake pipe 35.

  The upstream intake pipe 34 is made of, for example, resin, and an air cleaner 36 having a filter element 36 f is provided on the upstream side of the upstream intake pipe 34. The air from which dust or the like has been removed by the air cleaner 36 is taken into the intake pipe 34 on the upstream side. The downstream intake pipe 35 is formed integrally with the surge tank 37 and is fastened and fixed to the cylinder head 12 forming the intake port 1 b of the engine 1.

  On the other hand, in the engine body 10 of the engine 1, blow-by gas leaks from the combustion chamber 1 a through the gap between the cylinder 13 a and the piston 16 into the internal space of the crankcase 14. Therefore, in order to prevent deterioration of the engine oil and corrosion inside the engine body 10, the engine 1 is equipped with the ventilation device of the present embodiment for forcibly ventilating the inside of the crankcase 14 as a PCV blowby gas reduction device. Has been.

  Specifically, as shown in FIG. 2, the engine body 10 includes at least one ventilation passage that communicates the internal space of the head cover 11 and the cylinder head 12 that accommodates the valve mechanism 20 and the internal space of the crankcase 14. 10v is formed.

  Further, an air introduction pipe 41 for introducing fresh air from the intake passage 31 a upstream of the throttle valve 32, that is, new air into the engine body 10, is provided between the engine body 10 and the upstream intake pipe 34. A blow-by gas recirculation pipe that is interposed between the engine main body 10 and the downstream intake pipe 35 to recirculate blow-by gas generated inside the engine main body 10 to the intake passage 31b downstream of the throttle valve 32. 42 and a PCV valve 50 capable of opening and closing a reflux passage in the blow-by gas reflux pipe 42 are interposed.

  As a result, fresh air is introduced into the internal space of the engine 1 through the air introduction pipe 41 as shown by white arrows in FIG. 2, and from each cylinder 15 to the crankcase as shown by black arrows in FIG. The blow-by gas leaking into the engine 14 is sent from the crankcase 14 to the interior space of the head cover 11 and the cylinder head 12 through the ventilation passage 10v, passes through the PCV valve 50 and the blow-by gas return pipe 42, and is downstream of the throttle valve 32. It recirculates to the intake passage 31b on the side.

  The PCV valve 50 is mounted, for example, at a site where the blow-by gas recirculation pipe 42 is connected to the head cover 11 of the engine body 10. Of course, when the blow-by gas recirculation passage passes through a member below the head cover 11, the PCV valve 50 is connected to another portion of the engine body 10 and the blow-by gas recirculation pipe or from the inside of the engine body. It may be mounted on the outlet side of the oil separator through which the blowby gas passes.

  The PCV valve 50 is interposed between the engine body 10 of the engine 1 and the intake pipe 35 on the downstream side. When the valve is opened, blow-by gas generated inside the engine body 10 passes through the blow-by gas recirculation pipe 42 to the downstream side. Can be recirculated into the intake pipe 35.

  The PCV valve 50 includes a case 51 interposed between the engine body 10 of the engine 1 and the intake pipe 35 on the downstream side, and a magnetic body (for example, a ferromagnetic body) movably accommodated in the case 51. The valve body member 52 which consists of this.

  The case 51 includes a passage 51w that becomes a part of a return passage from the inside of the engine body 10 for blow-by gas to the inside of the intake pipe 35 on the downstream side, and an annular first valve seat portion that forms a part of the passage 51w. 51t (valve seat part) and the 2nd valve seat part 51s.

  The valve body member 52 is configured so that the first valve seat 52u at one end thereof is connected to the first valve seat portion 51t according to the pressure difference (pressure difference) between the inside of the engine body 10 and the inside of the intake pipe 35 on the downstream side. The valve body member 52 can be moved in the axial direction so as to be seated and engaged with the first valve seat portion 51t, and the valve body member 52 can seat the first valve portion 52u on the first valve seat portion 51t. As a result, the PCV valve 50 is fully closed, and the valve member 52 disengages the first valve portion 52u from the first valve seat portion 51t, whereby the PCV valve 50 is opened.

  When the valve body member 52 moves so that the first valve portion 52u on one end side thereof is separated from the first valve seat portion 51t, the second valve portion 52v having a conical shape on the other end side is moved to the second valve. When the second valve portion 52v of the valve body member 52 approaches the vicinity of the second valve seat portion 51s set in advance, the second valve of the valve body member 52 is made to approach the seat portion 51s. Between the portion 52v and the second valve seat portion 51s of the case 51, the annular passage 50w, which is the passage 51w around the valve body member 52, is restricted (the cross-sectional area is reduced). The opening degree of the PCV valve 50 is made smaller in accordance with the degree of.

  The PCV valve 50 further includes a compression coil spring 53 interposed between the case 51 and the valve body member 52, and the valve body member 52 is normally closed by the compression coil spring 53. 1 valve part 52u is urged | biased to the 1st valve seat part 51t.

  On the other hand, an electromagnetic coil 55 is wound around the outer peripheral wall portion 51e of the case 51 or embedded in a wound state. The electromagnetic coil 55 changes the valve body member 52 in the direction that changes the strength of the diaphragm, that is, the shaft. It is possible to generate an electromagnetic force that urges one side or the other side of the direction.

  The electromagnetic coil 55 has a part of the case 51 (a part corresponding to one end of the yoke) and the valve body member 52 when an excitation current (current for exciting the electromagnetic coil 55) is supplied by the ECU 60 described later. The other end of the case 51 (the portion corresponding to the other end of the yoke) and the other end side of the valve body member 52 are magnetized to the S pole so that one end side of the valve body member 52 is magnetized to the S pole. The conical second valve portion 52v is urged in the direction of approaching the second valve seat portion 51s, and the electromagnetic urging force opens the valve body member 52 by the differential pressure of the compression coil spring 53. The urging force in the valve direction is assisted.

  That is, the PCV valve 50 can shift the position of the valve body member 52 that is responsive to the differential pressure to a position equivalent to a further increase in the differential pressure by the electromagnetic biasing force on the valve body member 52 by the electromagnetic coil 55. It is possible to change the flow characteristics.

  In this case, by changing the magnitude of the excitation current supplied to the electromagnetic coil 55 in stages, the degree of assist by the electromagnetic biasing force can be switched. In this embodiment, the excitation to the electromagnetic coil 55 is performed by the ECU 60. The presence / absence of current supply and the direction switching of the excitation current (switching to reverse the direction of the magnetic field generated by the electromagnetic coil 55) are executed.

  Here, a permanent magnet 57 is attached to a part of the case 51, for example, a part of the case 51 closer to the intake pipe 35 than the second valve seat portion 51 s, and the direction of the excitation current supplied to the electromagnetic coil 55. When the magnetic poles of the valve body member 52 are reversed by reversing the direction of the valve body 52, the conical second valve portion 52v on the distal end side of the valve body member 52 is biased in a direction to separate from the second valve seat portion 51s. Be able to.

  Instead of providing the permanent magnet 57, the flange portion 52f serving as the spring receiving portion of the valve body member 52 is positioned on the left end side in FIG. 1, and the valve body from the first valve seat portion 51t of the case 51 is provided. When the first valve portion 52u of the member 52 is detached but within a certain separation distance, and the amount of movement of the valve body member 52 moves the second valve portion 52v to the vicinity of the second valve seat portion 51s. When excitation current is supplied to the electromagnetic coil 55 each time they approach (in addition, the case 51 and the valve body member 52 may be provided with annular portions that are close to each other when the electromagnetic coil 55 is excited), and when the differential pressure is small It is also conceivable that the magnetic path through which the magnetic flux generated by the electromagnetic coil 55 passes is partially formed at different positions by the proximity of the case 51 and the valve body member 52 being different. Such a magnetic circuit configuration itself can be configured in the same manner as a bistable or tristable solenoid, for example, and will not be described in detail here.

  The ECU 60 includes a backup memory such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a nonvolatile memory, although a specific hardware configuration is not illustrated. The input interface circuit includes a converter and the like, and the output interface circuit includes a driver and a relay switch.

  The ECU 60 always holds estimated intake pipe pressure information calculated based on sensor information from the intake pipe pressure sensor 66 and the engine speed sensor 67. Based on the estimated intake pipe pressure information, the ECU 60 It has a function of differential pressure detecting means 61 for detecting the differential pressure before and after (upstream and downstream in the blow-by gas recirculation direction).

  In addition, the ECU 60 selectively applies the exciting current of the electromagnetic coil 55 to the electromagnetic coil 55 in a state where the differential pressure detected by the differential pressure detecting means 61 has reached a differential pressure level at which the valve body member 52 can be moved. It also has the function of the excitation drive means 62 to supply.

  Here, selectively supplying the exciting current to the electromagnetic coil 55 means that when the flow rate characteristic of the PCV valve 50 may be a flow characteristic having only differential pressure response, the exciting current is not supplied to the electromagnetic coil 55 and only the differential pressure response is provided. When it is necessary to shift the differential pressure to an increase side or a decrease side from the flow rate characteristic, an excitation current that generates an electromagnetic force in a direction to assist or suppress the movement of the valve body member 52 is supplied to the electromagnetic coil 55. In other words, there are times when current is supplied and when current is not supplied.

  The excitation drive means 62 is released from the fully closed state (state shown by a solid line in FIG. 1) in which the valve body member 52 of the PCV valve 50 closes the inlet port portion 51a of the case 51, and the axial direction thereof according to the change in the differential pressure. Is selected in the electromagnetic coil 55 on the basis of the operating state of the engine 1 when it is in a moving region (hereinafter referred to as an intermediate region) in which it can start moving (indicated by a dotted line in FIG. 1). In addition, by supplying an exciting current, the flow rate characteristic of the PCV valve 50 is switched to a flow rate characteristic suitable for the current operating state.

  Specifically, the flow rate characteristic of the PCV valve 50 is, for example, as shown by a solid line in FIG. 3, when the differential pressure rises at the normal time when the electromagnetic coil 55 is not energized (non-energized), The valve opening operation that rapidly increases is performed, and the flow rate of the PCV valve 50 increases as the differential pressure increases until the differential pressure value ΔP1 is reached. In addition, a large flow rate with a substantially constant flow rate value is maintained between the differential pressure value ΔP1 and the differential pressure value ΔP2. When the differential pressure value ΔP2 is exceeded, the differential pressure increases until the differential pressure value ΔP3 is reached. Accordingly, the flow rate decreases, and a small flow rate with a substantially constant flow rate value is maintained between the differential pressure value ΔP3 and the differential pressure value ΔP4. When the differential pressure value ΔP4 is exceeded, the flow rate suddenly decreases and the valve is closed. Migrate to Here, the differential pressure values ΔP1 to ΔP4 are approximate values. Further, in the PCV valve 50 of the present embodiment, even when the differential pressure becomes sufficiently large, the state in which the second valve portion 52v of the valve body member 52 and the second valve seat portion 51s of the case 51 are engaged is reached. There is no restriction, and the annular passage 50w is in a squeezed state between which the cross-sectional area is reduced from the front and rear portions.

  On the other hand, when the exciting current is supplied to the electromagnetic coil 55, the flow rate characteristic of the PCV valve unit 50 changes as indicated by a broken line and a one-dot chain line in FIG. In FIG. 3, the maximum flow rate in each flow rate characteristic is exaggerated and greatly changed, but is formed between the first valve seat portion 51 t of the case 51 and the first valve portion 52 u of the valve body member 52. The cross-sectional area of the upstream variable passage portion and the cross-sectional area of the downstream variable passage portion formed between the second valve seat portion 51s of the case 51 and the second valve portion 52v of the valve body member 52 are the same. Even if the pressure difference is different, the shape of the case 51 and the valve body member 52 is set so that the flow rate characteristics are preferable and the preferable flow rate characteristics are set, thereby causing a change in the maximum flow rate in the illustrated direction. .

  When the excitation current supplied to the electromagnetic coil 55 flows toward the pressure difference decreasing side (in the (−) direction in FIG. 3), for example, as shown by the broken line in FIG. The valve opening operation that rapidly increases is performed, and the flow rate of the PCV valve 50 increases as the differential pressure increases until the differential pressure value ΔP1a that is larger than the differential pressure value ΔP1 is reached. Further, a large flow rate with a substantially constant flow rate value is maintained between the differential pressure value ΔP1a and the differential pressure value ΔP2a larger than the differential pressure value ΔP2, and when the differential pressure value ΔP2a is exceeded, the differential pressure close to the differential pressure value ΔP3 is maintained. Until the value ΔP3a is reached, the flow rate decreases as the differential pressure increases. When the differential pressure value ΔP3a is exceeded, the flow rate is maintained at a small flow rate. That is, in this case, since the second valve portion 52v of the valve body member 52 and the second valve seat portion 51s of the case 51 are less likely to approach than usual, even if the differential pressure becomes sufficiently large, the annular passage 50w The aperture will never be too tight.

  When the exciting current supplied to the electromagnetic coil 55 flows on the differential pressure increasing side (in the (+) direction in FIG. 3), for example, as shown by the one-dot chain line in FIG. Until the pressure difference value ΔP1b close to the pressure difference value ΔP1 is reached, the flow rate of the PCV valve 50 increases as the pressure difference increases. Further, a large flow rate with a substantially constant flow rate value is maintained between the differential pressure value ΔP1b and the differential pressure value ΔP2b smaller than the differential pressure value ΔP2, and when the differential pressure value ΔP2b is exceeded, the differential pressure close to the differential pressure value ΔP2 is maintained. Until the value ΔP3b is reached, the flow rate decreases as the differential pressure increases, and when the differential pressure value ΔP3b is exceeded, the flow rate is maintained at a small flow rate comparable to that when the differential pressure value ΔP4 in the normal flow characteristics is exceeded. The That is, in this case, the restriction of the annular passage 50w becomes tight from the stage where the differential pressure does not become so high.

  The ECU 60 further reaches a differential pressure level at which the differential pressure detected by the function of the differential pressure detection means 61 can move the valve body member 52, and the electromagnetic coil 55 is in a non-excited state (the current for excitation drive is In the state of not being supplied), an induced current generated in the electromagnetic coil 55 due to the movement of the valve body member 52 is detected, and whether or not the movable state of the valve body member 52 is normal is determined based on the detected value. It has a function as the movable state determination means 63.

  Specifically, for example, when at least the electromagnetic coil 55 is in a non-excited state (a state in which current for excitation driving is not supplied), the ECU 60 determines that the differential pressure detected by the function of the differential pressure detecting means 61 is the valve body member. Whether or not a differential pressure level that can move 52 has been reached is monitored at regular intervals, and when the differential pressure has reached a differential pressure level that can move the valve body member 52, the elapsed time from that time When a predetermined standby time (for example, several seconds) is exceeded, the induced current flowing through the electromagnetic coil 55 is detected by monitoring the voltage between the terminals of the electromagnetic coil 55.

  When the valve body member 52 is in a normal operation state that responds to the differential pressure across the engine 1 during operation of the engine 1 and no excitation current is supplied to the electromagnetic coil 55, there is no valve between the terminals of the electromagnetic coil 55. Since an induced current corresponding to the movement of the body member 52 flows, an effective voltage of a certain level or more is generated between the terminals of the electromagnetic coil 55. On the other hand, when the valve body member 52 is in a fixed state (in a state where it is not movable) and no excitation current is supplied to the electromagnetic coil 55, the valve body member 52 is moved between the terminals of the electromagnetic coil 55. Since no corresponding induced current flows, an effective voltage corresponding to the movement of the valve body member 52 is not detected between the terminals of the electromagnetic coil 55.

  Based on the detected value of the voltage between the terminals of the electromagnetic coil 55, the movable state determining means 63 of the ECU 60 determines that the movable state of the valve body member 52 is normal when the detected value exceeds a preset determination threshold. When the detected value is equal to or less than a predetermined determination threshold value, it is determined that the valve body member 52 is in a fixed state. The function of the movable state determination means 63 is incorporated as one of failure diagnosis programs in a known on-board failure diagnosis circuit (so-called OBD (On Board Diagnosis) circuit), for example, When the determination is made, for example, warning information notifying the driver of a malfunction of the engine 1 is issued by, for example, MIL (Malfunction indicator lamp), and code information indicating the fixed state of the valve body member 52 can be referred to during maintenance. Processing such as writing to is executed.

  Next, the operation will be described.

  In the ventilation device for an internal combustion engine of the present embodiment configured as described above, when the engine 1 is in operation, the combustion chamber 1a of the engine 1 passes through the gap between the cylinder 13a and the piston 16 and enters the crankcase 14. When the blow-by gas leaks, the valve body member 52 of the PCV valve 50 corresponds to the differential pressure before and after that, that is, the difference between the pressure (atmospheric pressure) inside the engine body 10 and the pressure inside the intake pipe 35 on the downstream side. By moving in the axial direction, according to the differential pressure across the PCV valve 50, the return of the blow-by gas from the inside of the engine body 10 passing through the blow-by gas return pipe 42 to the inside of the intake pipe 35 on the downstream side is allowed.

  In this state, the differential pressure detection means 61 of the ECU 60 calculates estimated intake pipe pressure information based on sensor information from the intake pipe pressure sensor 66 and the engine speed sensor 67, and the estimated intake pipe pressure information is included in the estimated intake pipe pressure information. Based on this, the differential pressure across the PCV valve 50 is detected. In addition, when the differential pressure level of the PCV valve 50 reaches a differential pressure level at which the valve body member 52 can be moved by the excitation driving means 62, the electromagnetic coil 55 is excited and driven in that state. A current is selectively supplied to the electromagnetic coil 55.

  For example, in an operating state in which the fuel is diluted to save fuel consumption during idling or after idling, the flow rate of the PCV valve 50 is set to the throttle side where the flow rate of the PCV valve 50 is suppressed, for example, to the differential pressure increasing side. In the warm-up (warm-up) process, the flow characteristics of the PCV valve 50 are switched to the opening increasing side where the flow of the PCV valve 50 is increased, for example, the differential pressure decreasing side.

  Thus, in this embodiment, since the movement of the valve body member 52 that responds to the differential pressure is assisted or suppressed by the excitation drive of the electromagnetic coil 55, the current for exciting the electromagnetic coil 55 is set to the electromagnetic coil. When the electromagnetic coil 55 is selectively supplied, the normal flow rate characteristic of the PCV valve 50 that responds to the differential pressure under the non-excited state of the electromagnetic coil 55 (for example, the characteristic of the solid line in FIG. 3) and the excited state of the electromagnetic coil 55 Below, it is possible to switch to another flow rate characteristic (for example, the characteristic of the broken line or the alternate long and short dash line in FIG. 3) that shifts from the normal flow rate characteristic to the increase side or the decrease side of the differential pressure.

  In addition, the driving of the valve body member 52 is not performed by the electromagnetic coil 55 alone, but the electromagnetic biasing force by the excitation drive of the electromagnetic coil 55 is applied to the valve body member 52 that has moved to the intermediate region that has been released from the fully closed state due to the differential pressure. Therefore, the high-power electromagnetic drive means is not required as in the prior art, and the PCV valve 50 can be made compact and low-cost.

  In this embodiment, the direction of the current for exciting and driving the electromagnetic coil 55 is also switched so that the flow rate characteristic different from the normal flow rate characteristic of the PCV valve 50 is on the higher side of the differential pressure than the normal characteristic. Since the flow characteristic is shifted to the flow characteristic that shifts to the lowering side of the differential pressure (for example, the flow characteristic of the broken line and the one-dot chain line in FIG. 3), the flow characteristic of the PCV valve 50 can be switched in three stages.

  Furthermore, in the present embodiment, when the differential pressure across the PCV valve 50 reaches a differential pressure level at which the valve body member 52 can be moved, and the electromagnetic coil 55 is in a non-excited state, the movable state determining means 63 Whether or not the movable state of the valve body member 52 is normal is determined based on whether or not an induced current to be generated in the electromagnetic coil 55 is detected by the movement of the valve body member 52 responsive to the pressure. Thus, it is possible to reliably detect the fixed state.

  Further, the movable state determination means 63 uses the electromagnetic coil 55 and the differential pressure detection means 61 that are used for switching the flow characteristics of the PCV valve 50 to execute the movable state determination of the valve body member 52. The state determination means 63 can be realized with a simple configuration, and can be easily incorporated into an on-board failure diagnosis circuit mounted on the in-vehicle ECU.

  As described above, in the ventilation device for the internal combustion engine of the present embodiment, the flow characteristic of the PCV valve 50 that responds to the differential pressure can be obtained by selectively supplying the excitation drive current to the electromagnetic coil 55. In order to obtain a flow characteristic suitable for the state, it is possible to switch between a flow characteristic in the non-excited state of the electromagnetic coil 55 and a flow characteristic in the excited state, and the driving of the valve body member 52 is performed only by the electromagnetic coil 55. Therefore, the high-power electromagnetic drive means is not required, and the PCV valve 50 can be made compact and low-cost. Further, since whether or not the movable state of the valve body member 52 is normal is determined using the differential pressure generation information and the detection information of the induced current to be generated in the electromagnetic coil 55 at that time, the PCV valve 50 sticking states can be detected reliably.

  In the ventilation device for an internal combustion engine according to the above-described embodiment, the internal combustion engine is a gasoline engine. However, it is needless to say that the internal combustion engine may use another fuel (for example, ethanol). A diesel engine may be used. Further, the PCV valve 50 is provided, for example, at a portion where the blow-by gas recirculation pipe 42 is connected to the head cover 11 of the engine body 10, but depending on the arrangement of the blow-by gas recirculation passage, a hole penetrating the cylinder head, the cylinder head or the crankcase A PCV valve can also be attached to the oil separator connected to the hole or the hole.

  Further, the case 51 and the valve body member 52 of the PCV valve 50 shown in FIG. 1 have a straight shape that forms a cylindrical wall surface in the vicinity of the inlet port portion 51a and the outlet port portion 51b. Of course, the passage cross-sectional area can be appropriately changed between the ports 51a and 51b so as to obtain a preferable flow rate characteristic according to the displacement of the valve body.

  Further, in the above-described embodiment, the direction of the electromagnetic urging force generated by the electromagnetic coil 55 is switched between the valve opening direction and the valve closing direction (either the valve opening direction or the valve closing direction, for example, both). However, as described above, even if the magnitude of the urging force in one direction (the urging force in any one of the valve opening direction and the valve closing direction) is changed by changing the magnitude of the excitation current, Good. Further, when the differential pressure is small and large, the proximity portion of the case 51 and the valve body member 52 is made different, and the path (magnetic path) of the magnetic flux generated by the electromagnetic coil 55 is partially made different, so that It is also conceivable to switch the direction of electromagnetic biasing to the valve body member 52 or bias it to a specific position in the intermediate region. Further, only the presence / absence of the electromagnetic biasing force by the electromagnetic coil 55 may be switched.

  As described above, the ventilation device for an internal combustion engine according to the present invention selectively supplies the excitation drive current to the electromagnetic coil, thereby changing the flow characteristic of the PCV valve that responds to the differential pressure to the operating state of the internal combustion engine. The flow rate characteristics can be switched between the non-excited state of the electromagnetic coil and the flow rate characteristic under the excited state so that the valve body is driven only by the electromagnetic coil. There is an effect that it is possible to provide a ventilation device for an internal combustion engine in which a PCV valve can be made compact and low cost without requiring a high output electromagnetic drive means. The present invention is useful in general ventilation systems for internal combustion engines having a PCV valve that allows the return of blow-by gas to the inside and restricts the reverse flow.

1 engine (internal combustion engine)
DESCRIPTION OF SYMBOLS 10 Engine body 10v Ventilation passage 14 Crankcase 15 Cylinder 31 Intake passage 31a Upstream intake passage 31b Downstream intake passage 34 Upstream intake pipe 35 Downstream intake pipe 37 Surge tank 41 Air introduction pipe 42 Blow-by gas recirculation pipe 50 PCV valve 50w annular passage 51 case 51a inlet port part 51b outlet port part 51e outer peripheral wall part 51s second valve seat part 51t first valve seat part (valve seat part)
51w passage 52 valve body member 52f flange part 52u first valve part 52v second valve part 55 electromagnetic coil 57 permanent magnet 60 ECU
61 Differential pressure detection means 62 Excitation drive means 63 Movable state determination means 66 Intake pipe pressure sensor 67 Engine speed sensor

Claims (1)

A PCV valve interposed between the engine body of the internal combustion engine and the intake pipe, and capable of returning the blow-by gas generated inside the engine body to the inside of the intake pipe;
The PCV valve is interposed between the engine body and the intake pipe, and has a valve seat portion that forms a part of a return passage for the blow-by gas from the inside of the engine body to the inside of the intake pipe. The case moves in a valve closing direction approaching the valve seat portion and a valve opening direction away from the valve seat portion in accordance with a differential pressure between the inside of the engine body and the inside of the intake pipe. And a resilient member interposed between the case and the valve body member so as to bias the valve body member in the valve closing direction. In a ventilation device for an internal combustion engine,
An electromagnetic coil capable of generating an electromagnetic force that urges the valve body member in at least one direction of the valve closing direction and the valve opening direction;
Differential pressure detecting means for detecting the differential pressure;
A current for exciting and driving the electromagnetic coil is selectively supplied to the electromagnetic coil in a state where the differential pressure detected by the differential pressure detecting means has reached a differential pressure level at which the valve body member can be moved. Excitation drive means;
When the differential pressure detected by the differential pressure detection means reaches a differential pressure level at which the valve body member can be moved and the electromagnetic coil is in a non-excited state, the electromagnetic coil is moved by the movement of the valve body member. A ventilation apparatus for an internal combustion engine, comprising: a movable state determining means for determining whether or not the movable state of the valve body member is normal based on an induced current generated in the engine.

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