JP2010096028A - Crankcase emission control system for internal combustion engine - Google Patents

Abstract

To provide a blow-by gas reduction device for an inner edge engine capable of variably setting oil separation performance from blow-by gas.
A blow-by gas reduction device for an engine includes a PCV valve 20 that is a separation mechanism that separates oil from blow-by gas and returns the separated oil through a discharge port to a storage unit. The PCV valve 20 includes a case 21 having a space for allowing blow-by gas to pass through, a valve body 22 that is housed in the case 21 and forms a passage for the blow-by gas between the case 21 and the valve body 22. And an actuator 23 that changes the interval PS between the case 21 and the valve body 22.
[Selection] Figure 2

Description

  The present invention relates to a blow-by gas reduction device for an internal combustion engine that includes a separation mechanism that separates oil from blow-by gas and returns the separated oil to a storage unit through a discharge port.

  In addition to the PCV (Positive Crankcase Ventilation) valve that adjusts the flow rate of the blow-by gas, the blow-by gas reducing device allows the blow-by gas to pass through the process of supplying the blow-by gas in the crankcase to the intake passage. Is provided with a separator (separation mechanism) for separating the components (hereinafter referred to as “oil”) of the engine lubricating oil contained in. As a blow-by gas reduction device having this separator, for example, the one described in Patent Document 1 is known.

  With reference to FIG. 7, the structure of the separator provided in the conventional blow-by gas reduction apparatus will be described. In addition, the arrow in the main-body part 110 in FIG. 7 has shown the flow of blow-by gas.

  As shown in FIG. 7, the separator 100 formed in the cylinder head cover is provided with gas inlets 111 and 112, a gas outlet 113, and an oil outlet 114 in the main body 110. The main body 110 is provided with a guide member 115 that guides the blow-by gas and a separation unit 116 that separates the oil contained in the blow-by gas. The separation unit 116 is configured by a plurality of bypass plates 117, 118, and 119, and is formed so that a flow path through which blow-by gas passes through the main body 110 becomes long.

The blow-by gas that has flowed into the main body 110 from the gas inlets 111 and 112 generates a vortex by the guide member 115 and collides with the bypass plates 117 to 119. Thereby, the oil component contained in blow-by gas adheres to the detour plates 117 to 119. The oil adhering to the bypass plates 117 to 119 is discharged to the outside from the main body 110 through the oil outlet 114 and is returned to the oil pan through the bypass path connected to the oil outlet 114. The blow-by gas is supplied to the intake manifold through the gas outlet 113.
JP 2005-23824 A

  By the way, in the separator 100 having the above structure, the flow path width formed between the guide member 115 and the bypass plate 117, between the bypass plate 117 and the bypass plate 118, and between the bypass plate 118 and the bypass plate 119. Is constant.

  Therefore, when the flow rate of blow-by gas passing through the separator 100 is large, a large amount of oil adheres to the bypass plates 117 to 119 because a large amount of blow-by gas collides with the bypass plates 117 to 119. As a result, the separator 100 can separate a large amount of oil. However, when the amount of blow-by gas that passes through the separator 100 is small, the amount of oil that adheres to the bypass plates 117 to 119 decreases because the amount of blow-by gas that collides with the bypass plates 117 to 119 is small. As a result, the amount of oil that can be separated by the separator 100 is reduced. Therefore, when the amount of blow-by gas that passes through the separator 100 is small, the separator 100 cannot effectively separate the oil contained in the blow-by gas.

  In other words, in the conventional blow-by gas reduction device, the structure of the separator is devised to promote the separation of oil from the blow-by gas, but the oil separation performance is improved according to the engine operating conditions and the like. It was not possible to change actively.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a blow-by gas reduction device for an internal combustion engine capable of variably setting oil separation performance from blow-by gas.

In the following, means for achieving the above object and its effects are described.
(1) The invention according to claim 1 is a blow-by gas reduction device for an internal combustion engine comprising a separation mechanism that separates oil from blow-by gas and returns the separated oil to a storage unit via a discharge port. The separation mechanism includes a case having a space for allowing blow-by gas to pass through, a valve body that is accommodated in the case and forms a passage for the blow-by gas between the case, and the case that drives the valve body to the case. The gist is provided with an actuator for changing the distance from the valve body.

  According to this invention, since the size of the passage area of the blow-by gas is changed when the distance between the valve body and the case is changed, the flow rate of the blow-by gas passing between the valve body and the case is accordingly increased. To change. That is, the oil separation performance can be variably set by driving the valve body through the actuator.

  (2) The invention according to claim 2 is the blow-by gas reduction device for an internal combustion engine according to claim 1, wherein the actuator is configured to change the valve body based on a request to increase the oil separation performance. The gist is to reduce the interval by driving.

  According to the present invention, when the passage area of the blow-by gas is reduced, the flow rate of the blow-by gas is increased, so that more oil can be separated when the blow-by gas collides with the wall surface. In the above invention, since the space between the case and the valve body is reduced based on the request to increase the oil separation performance, thereby reducing the passage area of the blow-by gas, the oil separation performance is increased. ing.

  (3) The invention according to claim 3 is the blow-by gas reduction device for an internal combustion engine according to claim 1 or 2, wherein the separation mechanism also functions as an electronically controlled PCV valve that adjusts the flow rate of blow-by gas. The gist of the invention is that the oil separation performance and the blow-by gas flow rate are adjusted simultaneously by driving the valve body by the actuator.

  In recent years, as a valve for adjusting the flow rate of blow-by gas, it has been proposed to provide an electronically controlled PCV valve instead of a mechanical valve. In this case, although it is necessary to provide a new actuator for the electronically controlled PCV valve, it is considered that the practicality is sufficient in terms of enabling finer control of the blow-by gas flow rate. It is done. On the other hand, when an actuator is used to variably set the oil separation performance, an electronically controlled PCV valve is additionally required, so that two actuators are required, so there is a concern that, for example, an excessive increase in power consumption will occur. . In this regard, in the above invention, the adjustment of oil separation performance and the flow rate of blow-by gas are adjusted at the same time by a single actuator, so the function of variably setting the oil separation performance and the electronically controlled PCV valve The excessive increase in power consumption can be suppressed while providing the above function.

  (4) The invention according to claim 4 is the blow-by gas reduction device for an internal combustion engine according to claim 3, wherein the actuator reduces the demand to increase the oil separation performance and the blow-by gas flow rate. The gist is to drive the valve body and reduce the interval based on at least one of the requests.

  When the passage area of the blowby gas is reduced, the flow rate of the blowby gas is increased, so that more oil is separated when the blowby gas collides with the wall surface. Further, when the blow-by gas passage area is reduced, the blow-by gas flow rate is reduced. In the above invention, based on at least one of the request to increase the oil separation performance and the request to decrease the blow-by gas flow rate, the distance between the case and the valve body is reduced, thereby reducing the passage area of the blow-by gas. Since it is made small, the blow-by gas flow rate is reduced and the oil separation performance is increased.

  (5) The invention according to claim 5 is the blow-by gas reduction device for an internal combustion engine according to any one of claims 1 to 4, wherein the reduction device is configured to adjust the separation performance of oil and to control the flow rate of blow-by gas. The actuator further includes control means for controlling the actuator based on an engine operating state, and the actuator receives both a command signal for adjusting oil separation performance and a command signal for adjusting blow-by gas flow rate. It is received from the control means, and when the at least one of these signals is received, the valve body is driven based on the received command signal.

  According to this invention, since the actuator can receive both the command signal for adjusting the oil separation performance from the control means and the command signal for adjusting the blow-by gas flow rate, the actuator can receive these command signals. Compared to the case where only one of the two can be received, the interval between the valve body and the case can be adjusted according to many changes in the engine operation of the internal combustion engine.

  (6) The invention according to claim 6 is the blow-by gas reduction device for an internal combustion engine according to any one of claims 1 to 5, wherein the actuator is provided in an intake passage of the internal combustion engine to reduce an intake air amount. The gist is to drive the valve body in a direction to increase the oil separation performance as the opening degree of the intake air amount adjusting valve to be adjusted decreases.

  In an internal combustion engine, the amount of air supplied to the combustion chamber decreases as the opening of the intake air amount adjustment valve decreases, so the blow-by gas flow rate decreases. Since this blow-by gas flow rate decreases, the amount of oil separated decreases. However, according to the present invention, as the opening of the intake air amount adjustment valve decreases, that is, as the oil separation amount decreases, the oil separation is performed by driving the valve body in a direction that increases the oil separation performance. A decrease in the amount can be suppressed.

  (7) The invention according to claim 7 is the blow-by gas reduction device for an internal combustion engine according to any one of claims 1 to 6, wherein the reduction device has a function as an electronically controlled PCV valve. As a summary, only the separation mechanism is provided.

  According to the present invention, since the blow-by gas reduction device includes only the separation mechanism as a mechanism having a function as an electronically controlled PCV valve, it is not necessary to additionally include an electronically controlled PCV valve and a separation mechanism. Therefore, the structure of the blow-by gas reduction device can be simplified.

  (8) According to an eighth aspect of the present invention, in the blow-by gas reduction device for an internal combustion engine according to any one of the first to seventh aspects, the valve body extends toward the side wall of the case. A rotating side wall portion is provided, and a plurality of the rotating side wall portions are arranged with a predetermined gap in the circumferential direction of the valve body, and the case includes an inlet and an outlet serving as an inlet and an outlet of the blow-by gas. A fixed side wall portion extending toward the valve body, and a plurality of the fixed side wall portions are arranged with a predetermined gap in the circumferential direction, and the rotating side wall portions are adjacent to each other in the circumferential direction. The actuator is disposed between the fixed side wall portions, and the actuator changes the interval between the case and the valve body to rotate the valve body with respect to the case and the adjacent rotating side wall portions. Said solid And summarized in that to change the distance between the side wall portion.

  According to the present invention, a plurality of intervals formed by the plurality of fixed side wall portions and the plurality of rotation side wall portions can be variably set simultaneously by one operation of rotating the valve body. Therefore, it is possible to easily adjust the blow-by gas flow rate and the oil separation performance.

  (9) The invention according to claim 9 is the blow-by gas reduction device for an internal combustion engine according to claim 8, wherein the inflow port and the outflow port are arranged close to each other in the circumferential direction, and the case Is summarized in that a partition wall extending toward the valve body is provided in a portion between the inflow port and the outflow port.

  According to the present invention, the blow-by gas that has flowed into the case through the inflow port is prevented from immediately flowing into the outflow port adjacent thereto. That is, the blow-by gas that has flowed into the case flows around the valve body and then flows into the outlet. Therefore, it is possible to increase the number of collisions between the blow-by gas, the rotating side wall portion, and the fixed side wall portion, and improve the oil separation performance.

1 to 4, an embodiment in which the blow-by gas reduction device for an internal combustion engine of the present invention is embodied as a blow-by gas reduction device for an on-vehicle internal combustion engine will be described.
First, the configuration of the engine 1 will be described with reference to FIG.

  As shown in FIG. 1, in the engine 1, an intake passage 3 and an exhaust passage 4 are connected to a combustion chamber 2 of each cylinder. Then, air is sucked into the combustion chamber 2 through a throttle valve 11 provided in the intake passage 3 and fuel is injected and supplied from the fuel injection valve 5 into the intake passage 3. A mixture of air and fuel is supplied. When this air-fuel mixture burns based on ignition by the spark plug 6 of each cylinder, the piston 7 reciprocates due to the combustion energy at that time, and the crankshaft 8 that is the output shaft of the engine 1 rotates. The air-fuel mixture after combustion is sent as exhaust gas to the exhaust passage 4, and the exhaust gas is purified by the catalyst 4 a provided in the exhaust passage 4.

  In the engine 1, a part of the gas existing in the combustion chamber 2 in the compression stroke and the expansion stroke leaks into the crankcase 10 from between the piston ring 7 a and the cylinder inner wall 9 as blow-by gas. For this reason, the engine 1 is provided with a blow-by gas reduction device BR that returns the blow-by gas leaked from the combustion chamber 2 into the crankcase 10 to the intake passage 3 for processing.

  The blow-by gas reduction device BR is connected to a portion of the intake passage 3 on the upstream side of the throttle valve 11 and introduces fresh air into the crankcase 10, and the blow-by gas in the crankcase 10 is taken into the intake passage. A gas outflow passage 13 connected to a portion of the intake passage 3 on the downstream side of the throttle valve 11 is provided. The gas outflow passage 13 is provided with a PCV valve 20 for adjusting the flow rate of blowby gas when returning the blowby gas to the intake passage 3. The PCV valve 20 is an electronic control type whose opening is adjusted by an actuator 23 (see FIG. 2), and the flow rate of the gas flowing from the gas outflow passage 13 to the intake passage 3 is increased as the opening is adjusted to be larger. To do more. In the blow-by gas reduction device BR, blow-by gas leaked from the combustion chamber 2 into the crankcase 10 due to the introduction of fresh air from the fresh-air introduction passage 12 into the crankcase 10 is introduced into the intake passage through the gas outflow passage 13. Return to 3.

Next, the electrical configuration of the blow-by gas reduction device BR will be described.
The engine 1 includes an electronic control unit 14 that executes various controls based on the output of the sensor and the like. This electronic control unit 14 includes a CPU that executes various arithmetic processes related to the above control, a ROM that stores programs and data necessary for the control, a RAM that temporarily stores arithmetic results of the CPU, and the like. An input / output port for inputting / outputting signals is provided.

  Various sensors shown below are connected to the input port of the electronic control unit 14. In other words, the input port of the electronic control unit 14 is provided in the accelerator position sensor 16 for detecting the depression amount (accelerator depression amount) of the accelerator pedal 15 that is depressed by the driver of the vehicle and the intake passage 3 of the engine 1. A throttle position sensor 17 that detects the opening of the throttle valve 11, an air flow meter 18 that detects the amount of air that passes through the intake passage 3 and is sucked into the combustion chamber 2, and a signal corresponding to the rotation of the crankshaft 8. Is connected to the crank position sensor 19. The output ports of the electronic control device 14 are connected to drive circuits for various devices such as the fuel injection valve 5, the spark plug 6, the throttle valve 11, and the PCV valve 20.

  Next, the configuration of the PCV valve 20 will be described with reference to FIG. In addition, the arrow in Fig.2 (a) has shown the flow of blow-by gas. Hereinafter, the direction along the rotational axis J of the valve body 22 is referred to as “axial direction”, the rotational radial direction of the valve body 22 is referred to as “radial direction”, and the rotational circumferential direction of the valve body 22 is referred to as “circumferential direction”.

  As shown in FIG. 2, the PCV valve 20 includes a case 21, which is a main body having a space through which blow-by gas passes, and a valve that is accommodated in the case 21 and forms a blow-by gas passage between the case 21 and the case 21. A body 22 and an actuator 23 that rotationally drives the valve body 22 are provided. The actuator 23 rotates the valve body 22 around the rotation axis J with respect to the case 21, thereby changing the interval PS between the case 21 and the valve body 22, which is a passage for blow-by gas. Then, by changing the interval PS between the case 21 and the valve body 22, the separation performance for separating the oil component contained in the blow-by gas from the blow-by gas (hereinafter simply referred to as “oil separation performance”) is adjusted. . In the present embodiment, a stepping motor is used as the actuator 23.

  The PCV valve 20 can simultaneously adjust the flow rate of blow-by gas passing through the PCV valve 20 and adjust the oil separation performance. That is, by changing the size of the interval PS, the passage area of the blow-by gas (that is, in the space constituting the interval PS in the circumferential direction between the fixed side wall portion 216 and the rotating side wall portion 222 becomes a plane along the axial direction. The flow area of the blow-by gas passing between the fixed side wall part 216 and the rotating side wall part 222 changes, and the oil content is changed. Separation performance is adjusted.

  The case 21 includes a cylindrical side wall 214, an inflow port 211 that allows blow-by gas to flow into the case 21 from the outside of the case 21, and a flow that allows blow-by gas to flow out of the case 21 to the outside of the case 21. An outlet 212 and an outlet 213 for discharging the oil separated from the blow-by gas to the outside of the case 21 are provided. The inflow port 211, the outflow port 212, and the discharge port 213 are provided on the side wall 214, respectively. Further, the discharge port 213 is provided on the lower side in the vertical direction of the PCV valve 20.

  The inflow port 211 and the outflow port 212 are disposed so as to be close to each other in the circumferential direction. A plate-like partition wall 215 that suppresses the flow of blow-by gas from the inlet 211 in the direction X through the outlet 212 in the side wall 214 between the inlet 211 and the outlet 212. That is, a partition wall 215 is provided that prevents blow-by gas that has flowed into the case 21 through the inlet 211 from immediately flowing into the outlet 212 adjacent to the inlet 211. The partition wall 215 extends from the side wall 214 toward the valve body 22 along the radial direction.

  The side wall 214 is provided with a fixed side wall portion 216 extending toward the valve body 22. The fixed side wall portion 216 is formed in a plate shape toward the valve body 22 and a plurality of fixed side wall portions 216 are formed at regular intervals in the circumferential direction.

  The valve body 22 is connected to the output shaft 231 of the actuator 23, and includes a base portion 221 that rotates together with the output shaft 231, and a rotating side wall portion 222 that extends from the base portion 221 toward the side wall 214. . The rotating side wall part 222 is formed in a plate shape along the radial direction, and a plurality of the rotating side wall parts 222 are formed at regular intervals in the circumferential direction.

  The inner edge of the partition wall 215 of the case 21 forms a minute gap in the radial direction between the outer peripheral surface of the base portion 221 of the valve body 22, that is, the radially outer surface of the base portion 221. That is, in the PCV valve 20, blow-by gas flows from the inlet 211 to the outlet 212 through the partition 215 due to a minute gap between the inner edge of the partition 215 and the outer peripheral surface of the valve element 22. A seal 24 which is a labyrinth seal to be suppressed is formed.

  The fixed side wall portions 216 and the rotating side wall portions 222 are alternately arranged in the circumferential direction. And the outer edge of the rotation side wall part 222 in the radial direction is formed to be outside in the radial direction from the inner edge of the fixed side wall part 216 in the radial direction. Thereby, the blow-by gas passage 25 is formed between the fixed side wall portion 216 and the rotating side wall portion 222 in the circumferential direction. The size of the blow-by gas passage is changed by changing the interval PS.

  Here, the blow-by gas travels in the circumferential direction from the inflow port 211 in the direction Y that is opposite to the direction X, passes through the blow-by gas passage 25, and flows out to the outflow port 212. And in this space | interval PS, when blowby gas collides with the fixed side wall part 216 and the rotation side wall part 222, the oil content contained in blowby gas is isolate | separated from blowby gas. The separated oil is returned to the oil pan, which is a storage part in the crankcase 10 (see FIG. 1), through the discharge port 213.

Next, with reference to FIG. 3, the relationship between the magnitude of the engine load and the flow rate of blow-by gas leaking from the combustion chamber 2 into the crankcase 10 will be described.
FIG. 3 is a graph showing the relationship between the magnitude of the engine load and the flow rate of blow-by gas leaking from the combustion chamber 2 into the crankcase 10. As shown in FIG. 3, the flow rate of blow-by gas leaking from the combustion chamber 2 into the crankcase 10 is relatively small when the engine is under a low load (that is, the state shown in FIG. 3A). In addition, the flow rate of blow-by gas leaking from the combustion chamber 2 into the crankcase 10 is increased at the time of medium engine load (that is, the state of FIG. 3B) than at the time of low engine load. As the engine load increases, the flow rate of blow-by gas leaking from the combustion chamber 2 into the crankcase 10 increases. Further, at the time of high engine load (that is, the state shown in FIG. 3C), the flow rate of blow-by gas leaking from the combustion chamber 2 into the crankcase 10 is larger than that at the time of engine load.

Next, with reference to FIG.4 and FIG.5, the relationship between the flow volume of the gas which passes the PCV valve | bulb 20, and the drive state of the PCV valve | bulb 20 is demonstrated.
First, the relationship between the opening of the throttle valve 11 and the interval PS of the PCV valve 20 will be described with reference to FIG.

  FIG. 4 is a graph showing the relationship between the opening degree of the throttle valve 11 and the interval PS formed by the valve body 22 and the case 21 of the PCV valve 20. As shown in FIG. 4, the actuator 23 of the PCV valve 20 drives and adjusts the valve body 22 so that the interval PS changes in proportion to the opening degree of the throttle valve 11. That is, the valve body 22 is driven so that the interval PS increases as the opening degree of the throttle valve 11 increases. Thereby, as the opening degree of the throttle valve 11 increases, the flow rate of the blow-by gas and fresh air mixture passing through the PCV valve 20 (hereinafter referred to as “PCV flow rate”) increases.

  Specifically, the opening degree data of the throttle valve 11 detected by the throttle position sensor 17 is transmitted to the electronic control unit 14. The electronic control unit 14 transmits a command signal as a request for adjusting the interval PS to the actuator 23 based on the opening degree data.

  More specifically, the electronic control unit 14 transmits a command signal to the actuator 23 so as to increase the interval PS as the opening of the throttle valve 11 increases. And the actuator 23 which received the command signal drives the valve body 22 based on the command signal, and forms the space | interval PS large. Conversely, the electronic control unit 14 transmits a command signal to the actuator 23 so as to reduce the interval PS as the opening of the throttle valve 11 decreases. And the actuator 23 which received the command signal drives the valve body 22 based on a command signal, and forms the space | interval PS small.

Next, the relationship between the engine load and the interval PS of the PCV valve 20 will be described with reference to FIGS.
Since the opening degree of the throttle valve 11 becomes relatively small at the time of engine low load, the electronic control unit 14 sets the valve body 22 so that the interval PS of the PCV valve 20 becomes small based on the graph shown in FIG. To drive. Thereby, the PCV valve 20 is maintained in the state shown in FIG.

  Here, when the engine is under a low load, the flow rate of blow-by gas leaking from the combustion chamber 2 into the crankcase 10 is small, so the flow rate of blow-by gas passing through the PCV valve 20 is also small. Therefore, in the PCV valve 20, the amount of oil separated by blow-by gas colliding with the fixed sidewall 216 and the rotating sidewall 222 is reduced.

  In addition, when the engine is under a low load, the blowby gas flow rate leaking from the combustion chamber 2 to the crankcase 10 is small, so that the inside of the crankcase 10 can be appropriately ventilated even if the PCV flow rate is reduced.

  Therefore, the electronic control unit 14 increases the flow rate of the blow-by gas passing through the blow-by gas passage by reducing the interval PS of the PCV valve 20, that is, reducing the blow-by gas passage area. Thereby, separation of oil from blowby gas by blowby gas colliding with fixed side wall part 216 and rotation side wall part 222 can be promoted. As a result, when the engine is under a low load, the amount of oil separated from the blow-by gas per unit time can be increased.

  When the engine load is high, the opening degree of the throttle valve 11 increases as the engine load increases. Therefore, the electronic control unit 14 determines that the interval PS of the PCV valve 20 is based on the graph shown in FIG. The valve body 22 is driven so as to be larger. Thereby, the PCV valve 20 is maintained in the state shown in FIG. 5B, for example.

  Here, the flow rate of blow-by gas that leaks from the combustion chamber 2 into the crankcase 10 at the time of medium engine load becomes larger than that at the time of low engine load, and the flow rate of blow-by gas that passes through the PCV valve 20 also increases. Therefore, in order to improve the ventilation in the crankcase 10, it is necessary to increase the PCV flow rate.

  Therefore, the electronic control unit 14 increases the PCV flow rate by making the interval PS of the PCV valve 20 larger than the interval PS at the time of engine low load. At this time, as the interval PS increases, the oil separation performance, that is, the degree of increase in the flow velocity of the blow-by gas passing through the blow-by gas passage 25 is lower than when the engine is under low load. Since the blow-by gas flow rate increases, the oil separation amount separated from the blow-by gas is suppressed from rapidly decreasing with respect to the oil separation amount at the time of engine low load. Here, “the degree of increase in the flow velocity of the blow-by gas passing through the blow-by gas passage 25” is determined from the value of the flow velocity of the blow-by gas in the blow-by gas passage area constituted by the interval PS in the blow-by gas passage 25. The amount of change in the flow rate of the blowby gas obtained by subtracting the value of the flow rate of the blowby gas in the blowby gas passage 25 other than that.

  Since the opening degree of the throttle valve 11 becomes larger when the engine is heavily loaded than when the engine is loaded, the electronic control unit 14 determines that the interval PS between the PCV valves 20 is larger than when the engine is loaded based on the graph shown in FIG. The valve body 22 is driven so as to be larger. Thereby, the PCV valve | bulb 20 is maintained in the state shown, for example in FIG.5 (c).

  Here, when the engine is highly loaded, the flow rate of blowby gas leaking from the combustion chamber 2 into the crankcase 10 is larger than that when the engine is loaded, and the flow rate of blowby gas passing through the PCV valve 20 is also increased. Accordingly, in order to further improve the ventilation performance in the crankcase 10, it is necessary to increase the PCV flow rate more than the PCV flow rate at the time of engine load.

  Therefore, the electronic control unit 14 further increases the PCV flow rate by making the interval PS of the PCV valve 20 larger than the interval PS at the time of engine load. At this time, as the interval PS increases, the oil separation performance, that is, the degree of increase in the flow velocity of the blow-by gas passing through the blow-by gas passage 25 is lower than that during the engine load, but the PCV flow rate increases. Since the blow-by gas flow rate increases, the oil separation amount separated from the blow-by gas is suppressed from rapidly decreasing with respect to the oil separation amount at the time of engine load.

  Incidentally, the state of the PCV valve 20 shown in FIG. 5C is that when the opening degree of the throttle valve 11 is maximum, and the rotating side wall portion 222 is located at the intermediate position in the circumferential direction of the adjacent fixed side wall portion 216. To do. As a result, the PCV flow rate passing through the blow-by gas passage 25 becomes the maximum within a range that is changed by adjusting the interval PS, and the blow-by gas flow rate passing through the blow-by gas passage 25 is likewise the maximum.

  As described above, the electronic control unit 14 is based on the opening degree of the throttle valve 11, and the oil separation performance from the blowby gas required according to the engine load and the ventilation performance in the crankcase 10, that is, the blowby gas passage. The flow rate of blow-by gas passing through 25 and the flow rate of blow-by gas supplied to the intake passage 3 are ascertained, and the interval PS is changed accordingly.

Next, the “PCV valve control process” in which the electronic control unit 14 adjusts the size of the interval PS of the PCV valve 20 will be described with reference to FIG. 6.
First, in step S10, the target value of the interval PS of the PCV valve 20 is calculated from the opening degree of the throttle valve 11. Specifically, when the electronic control device 14 receives a signal from the throttle position sensor 17, the electronic control device 14 can obtain data on the opening degree of the throttle valve 11. The electronic control unit 14 then sets a target value of the interval PS of the PCV valve 20 (hereinafter referred to as “interval target value”) corresponding to the opening degree data of the throttle valve 11 based on the graph shown in FIG. It is determined.

  Next, in step S11, it is determined whether or not the actual size of the interval PS of the PCV valve 20 (hereinafter referred to as “interval actual value”) matches the interval target value. Specifically, the actual interval value is calculated based on the rotation amount of the stepping motor that is the actuator 23 (or the number of steps of the rotating body of the stepping motor). Then, the electronic control unit 14 compares the calculated interval actual value with the interval target value.

  Here, when the interval actual value matches the interval target value (YES in step S11), the electronic control unit 14 determines that the interval actual value is a suitable size of the interval PS. In step S <b> 12, the electronic control unit 14 transmits a command signal for maintaining the interval PS of the PCV valve 20 to the current state to the actuator 23.

  On the other hand, when the interval actual value does not match the interval target value (NO in step S11), the electronic control unit 14 determines that the interval actual value is not a suitable size of the interval PS. In step S13, it is determined whether the interval actual value is larger than the interval target value.

  Here, when the interval actual value is larger than the interval target value (YES in step S13), the electronic control unit 14 determines that the interval actual value is too large for the engine load. That is, it is determined that it is necessary to increase the oil separation performance and reduce the blow-by gas flow rate. In step S14, a signal indicating a request for increasing the separation performance and a request for decreasing the blow-by gas is transmitted to the actuator 23, and the actuator 23 reduces the size of the interval PS of the PCV valve 20 based on this signal. The valve body 22 is driven. That is, the electronic control unit 14 transmits a command signal to the actuator 23 so as to reduce the interval PS, and the actuator 23 that has received this command signal drives the valve body 22 of the PCV valve 20 to reduce the interval PS. .

  On the other hand, when the interval actual value is smaller than the interval target value (NO in step S13), the electronic control unit 14 determines that the interval actual value is too small with respect to the engine load. That is, it is determined that it is necessary to reduce the oil separation performance and increase the blow-by gas flow rate. In step S15, a signal indicating a request for reducing the separation performance and a request for increasing the flow rate of blow-by gas is transmitted to the actuator 23, and the actuator 23 causes the valve body 22 to increase the size of the interval PS of the PCV valve 20. To drive. That is, the electronic control unit 14 transmits a command signal so as to increase the interval PS to the actuator 23, and drives the valve body 22 of the PCV valve 20 by the actuator 23 that has received this command signal, thereby increasing the interval PS. . Through the above processing, the electronic control unit 14 changes the size of the interval PS of the PCV valve 20 according to the opening degree of the throttle valve 11.

[Effect of the embodiment]
According to the blow-by gas reduction apparatus of the present embodiment, the following effects can be achieved.
(1) In this embodiment, when the circumferential interval PS between the fixed sidewall portion 216 and the rotating sidewall portion 222, which is the interval between the valve body 22 of the PCV valve 20 and the case 21, is changed, the passage area of the blowby gas is changed. Since the size is changed, the flow velocity of the blow-by gas passing between the valve body 22 and the case 21 changes accordingly. That is, the oil separation performance can be variably set by driving the valve body 22 through the actuator 23.

  (2) In the present embodiment, by changing the interval PS of the PCV valve 20, it is possible to simultaneously adjust the flow rate of blow-by gas passing through the PCV valve 20 and the oil separation performance. That is, by changing the interval PS of the PCV valve 20, it is possible to balance the flow rate of blow-by gas passing through the PCV valve 20 and the oil separation performance. For example, when the flow rate of blow-by gas passing through the PCV valve 20 decreases, the oil separation performance also decreases. However, by reducing the interval PS, it is possible to suppress a decrease in oil separation performance. Further, for example, when the blow-by gas flow rate passing through the PCV valve 20 increases, the oil separation performance also increases. However, when the interval PS is narrow, the increase in the blow-by gas flow rate passing through the PCV valve 20 is inhibited. End up. Therefore, by increasing the interval PS, the oil separation performance decreases, but the blow-by gas flow rate passing through the PCV valve 20 can be increased.

  (3) In this embodiment, since the interval PS constitutes a blow-by gas passage, reducing the interval PS reduces the blow-by gas passage. Accordingly, the flow rate of blow-by gas passing through this interval PS can be reduced. As a result, when the actuator 23 requests to reduce the flow rate of blow-by gas passing through the PCV valve 20, the actuator 23 drives the valve body 22 to reduce the interval PS, thereby achieving the request. can do.

  (4) The opening degree of the throttle valve 11 is controlled based on the engine load. Based on this engine load, the flow rate of blow-by gas leaking into the crankcase 10 increases or decreases. That is, as the engine load decreases, the blow-by gas flow rate leaking into the crankcase 10 decreases. Accordingly, the flow rate of blow-by gas passing through the PCV valve 20 is reduced. As the flow rate of blow-by gas passing through the PCV valve 20 decreases, the number of times this blow-by gas collides with the fixed side wall portion 216 and the rotating side wall portion 222 decreases, so that the amount of decomposition of the oil decreases. Therefore, in the present embodiment, as the opening of the throttle valve 11 decreases, the actuator 23 drives the valve body 22 in a direction in which the oil separation performance increases, so that the engine load decreases, that is, the PCV valve 20. As the flow rate of the blow-by gas passing through the inside decreases, the valve body 22 is driven in a direction to increase the oil separation performance, so that a decrease in the oil separation amount can be suppressed.

  (5) In this embodiment, the blow-by gas reduction device BR includes only the PCV valve 20 for adjusting the flow rate of blow-by gas passing through the PCV valve 20 and adjusting the oil separation performance, so that the blow-by gas reduction device BR is additionally provided. It is no longer necessary to provide an electronically controlled PCV valve that adjusts the flow rate of blow-by gas passing through the gas and a separation mechanism that adjusts the oil separation performance, so that the structure of the blow-by gas reduction device can be simplified.

  (6) In this embodiment, since the partition wall 215 is provided in the case 21 of the PCV valve 20, the blow-by gas that has flowed in from the inflow port 211 flows in the circumferential direction Y of the case 21 and around the valve body 22. And then flow out from the outlet 212. That is, the length of the passage through which the blow-by gas passes through the case 21 can be made longer than when flowing from the inlet 211 toward the circumferential direction X of the case 21 and outflowing from the outlet 212. . Accordingly, when the blow-by gas passes through the case 21 as compared with the case where it flows in the circumferential direction X of the case 21 from the inlet 211 and flows out of the outlet 212, the fixed side wall 216 and the rotating side wall The number of times of collision with the part 222 can be increased. As a result, the oil separation performance can be improved.

  (7) In this embodiment, since the inflow port 211 and the outflow port 212 are adjacent in the circumferential direction, the length of the passage through which the blow-by gas in the case 21 passes can be increased. Therefore, since many fixed side wall parts 216 and rotating side wall parts 222 can be provided in the case 21, the number of times of collision with the fixed side wall parts 216 and the rotating side wall parts 222 can be increased. As a result, the oil separation performance can be improved.

  (8) In the present embodiment, the discharge port 213 provided in the case 21 of the PCV valve 20 is provided in the case 21 on the lower side in the vertical direction. Therefore, the oil content of the blow-by gas decomposed by colliding with the fixed side wall portion 216 and the rotating side wall portion 222 can flow to the discharge port 213 by the action of gravity. Thereby, since the mechanism for flowing oil into the discharge port 213 is not required, the case 21 can be formed with a simple configuration. As a result, the cost of the PCV valve 20 and the cost of the blow-by gas reducing device BR can be reduced.

  In particular, since the PCV valve 20 is provided above the crankcase 10 in the vertical direction, oil can flow from the discharge port 213 to the crankcase 10 through the bypass by the action of gravity. Therefore, since a mechanism for flowing oil into the crankcase 10 is not required in the bypass path, the bypass path can be formed with a simplified configuration. As a result, it is possible to achieve cost reduction of the bypass path and cost reduction of the blow-by gas reduction device BR.

(Other embodiments)
In addition, the said embodiment can also be changed and implemented as shown, for example below.
In the blow-by gas reduction device BR according to the present embodiment, the seal 24 serving as the labyrinth seal is formed by forming a minute gap between the partition wall 215 provided in the case 21 of the PCV valve 20 and the base portion 221 of the valve body 22. Although provided, the seal 24 is not limited to a labyrinth seal with a minute gap. For example, instead of the labyrinth seal, the seal 24 may be provided with another seal such as an oil seal or a mechanical seal.

  In the blow-by gas reduction device BR of the present embodiment, the PCV valve 20 is configured to accommodate the valve body 22 in the cylindrical case 21, but the configuration and shape of the PCV valve 20 are not limited to this. . For example, it is possible to change the blow-by gas passage by moving the bypass plates 117, 118, and 119 of the conventional separator 100 shown in FIG. Also, other separators may have a structure that can change the passage of blow-by gas.

  In the blow-by gas reduction device BR of the present embodiment, the PCV valve 20 has a function of adjusting the oil separation performance, but the oil separation performance may be adjusted by a device other than the PCV valve 20. For example, a separator may be provided in the blow-by gas reduction device BR in addition to the PCV valve 20, and a mechanism for adjusting the oil separation performance may be provided in the separator.

  In the blow-by gas reduction device BR of the present embodiment, the electronic control device 14 has transmitted a command signal for driving the valve element 22 to the actuator 23 of the PCV valve 20, but the device for transmitting the command signal to the actuator 23 is this It is not limited to. For example, the actuator 23 may be controlled by mounting an electronic control unit (ECU) other than the electronic control device 14 on the actuator 23.

  In the blow-by gas reduction device BR of the present embodiment, a stepping motor is used as the actuator 23 of the PCV valve 20, but the type of the actuator 23 is not limited to this. For example, as the actuator 23, a motor having another structure such as a motor with a brush or a brushless motor may be used. In particular, when using a brushless motor, a motor driven by sensorless control without using a position detection element such as a Hall element is preferable.

  In the blow-by gas reduction device BR of the present embodiment, the blow-by gas flow rate is estimated based on the opening degree of the throttle valve 11, but the estimation of the blow-by gas flow rate is not limited to this. For example, the blow-by gas flow rate may be estimated from the air flow meter 18 and the crank position sensor 19. Here, it can be estimated that the blow-by gas flow rate increases as the amount of air detected by the air flow meter 18 increases. The crank position sensor 19 can estimate that the blow-by gas flow rate increases as the rotational speed of the crankshaft increases. As a method for estimating the blow-by gas flow rate, for example, a flow meter may be provided in a part of the blow-by gas reduction device BR.

  In the blow-by gas reduction device BR of the present embodiment, when the actual interval value does not coincide with the target interval value based on the opening of the throttle valve 11, the electronic control unit 14 increases the blow-by gas flow rate with respect to the actuator 23 or Although the request | requirement of reduction and the increase or reduction | decrease of the separation performance of oil was performed, the request | requirement by the electronic control apparatus 14 is not limited to this. For example, the electronic control unit 14 may only request the actuator 23 to increase or decrease the flow rate of blow-by gas and to increase or decrease the oil separation performance.

The schematic diagram which shows the structure of the engine about embodiment which implemented the blow-by gas reduction apparatus of the internal combustion engine of this invention. (A) About PCV valve | bulb of the embodiment, sectional drawing which shows the cross-section which cut the case with the plane orthogonal to a rotating shaft. (B) About PCV valve | bulb of the embodiment, sectional drawing which shows the cross-section which cut the case by plane AA along a rotating shaft while showing the front structure. The graph which shows the relationship between the engine load state and blow-by gas flow rate of the internal combustion engine of the embodiment. The graph which shows the relationship between the opening degree of the throttle valve of the same embodiment, and the space | interval of a PCV valve. (A) About PCV valve | bulb of the embodiment, sectional drawing which showed the space | interval of the PCV valve | bulb in the case of engine low load. (B) Sectional drawing which showed the space | interval of the PCV valve in the case of engine load about the PCV valve of the embodiment. (C) About PCV valve | bulb of the embodiment, sectional drawing which showed the space | interval of the PCV valve | bulb in the case of engine high load. The flowchart which shows the "PCV valve control process" performed by the electronic control apparatus of the embodiment. Sectional drawing which shows the cross-section of the separator of the reduction apparatus about the blow-by gas reduction apparatus of the conventional internal combustion engine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine), 2 ... Combustion chamber, 3 ... Intake passage, 4 ... Exhaust passage, 4a ... Catalyst, 5 ... Fuel injection valve, 6 ... Spark plug, 7 ... Piston, 7a ... Piston ring, 8 ... Crank Shaft, 9 ... cylinder inner wall, 10 ... crankcase, 11 ... throttle valve, 12 ... fresh air introduction passage, 13 ... gas outflow passage, 14 ... electronic control device (control means), 15 ... accelerator pedal, 16 ... accelerator position sensor , 17 ... Throttle position sensor, 18 ... Air flow meter, 19 ... Crank position sensor, 20 ... PCV valve (electronically controlled PCV valve), 21 ... Case, 22 ... Valve body, 23 ... Actuator, 24 ... Seal, 25 ... Blow-by Gas passage, 211 ... inlet, 212 ... outlet, 213 ... outlet, 214 ... side wall, 215 ... partition, 216 ... solid Side wall portion, 221 ... base, 222 ... rotating sidewall portion, 231 ... output shaft.

Claims (9)

In a blow-by gas reduction device for an internal combustion engine that includes a separation mechanism that separates oil from blow-by gas and returns the separated oil to a storage unit via a discharge port.
The separation mechanism includes a case having a space for allowing blow-by gas to pass through, a valve body accommodated in the case and forming a passage for the blow-by gas between the case, and the case by driving the valve body And an actuator for changing the distance between the valve body and the valve body. The blow-by gas reduction device for an internal combustion engine according to claim 1,
The blow-by gas reduction device for an internal combustion engine, wherein the actuator drives the valve element to reduce the interval based on a request to increase the oil separation performance. The blow-by gas reduction device for an internal combustion engine according to claim 1 or 2,
The separation mechanism also has a function as an electronically controlled PCV valve that adjusts the blow-by gas flow rate, and the oil separation performance and the adjustment of the blow-by gas flow rate are simultaneously performed by driving the valve body by the actuator. A blow-by gas reduction device for an internal combustion engine characterized by being made. The blow-by gas reduction device for an internal combustion engine according to claim 3,
The actuator drives the valve body based on at least one of a request to increase the oil separation performance and a request to reduce the blow-by gas flow rate to reduce the interval. A blow-by gas reduction device for an internal combustion engine. The blow-by gas reduction device for an internal combustion engine according to any one of claims 1 to 4,
The reduction device further includes control means for controlling the actuator based on the engine operating state for adjusting the oil separation performance and adjusting the blow-by gas flow rate,
The actuator receives both a command signal for adjusting oil separation performance and a command signal for adjusting blow-by gas flow rate from the control means, and when receiving at least one of these signals, A blow-by gas reduction device for an internal combustion engine, which drives the valve body based on a received command signal. The blow-by gas reduction device for an internal combustion engine according to any one of claims 1 to 5,
The actuator is an intake air amount adjusting valve that is provided in an intake passage of an internal combustion engine and adjusts the intake air amount, and drives the valve body in a direction that increases oil separation performance as the opening degree decreases. A blow-by gas reduction device for an internal combustion engine. The blow-by gas reduction device for an internal combustion engine according to any one of claims 1 to 6,
The reduction device includes only the separation mechanism as a mechanism having a function as an electronically controlled PCV valve. A blow-by gas reduction device for an internal combustion engine. The blow-by gas reduction device for an internal combustion engine according to any one of claims 1 to 7,
The valve body is provided with a rotating side wall portion extending toward the side wall of the case, and a plurality of the rotating side wall portions are arranged with a predetermined gap in the circumferential direction of the valve body,
The case includes an inlet and an outlet serving as an inlet and an outlet for the blow-by gas, and a fixed side wall portion extending toward the valve body, and the fixed side wall portion has a predetermined shape in the circumferential direction. A plurality are arranged through a gap,
The rotating side wall portion is disposed between the fixed side wall portions adjacent to each other in the circumferential direction, and the actuator changes the interval between the case and the valve body so that the valve body is used as the case. A blow-by gas reduction device for an internal combustion engine, wherein the blow-by gas reduction device is configured to change an interval between the rotating side wall and the fixed side wall adjacent to each other. The blow-by gas reduction device for an internal combustion engine according to claim 8,
The inflow port and the outflow port are arranged close to each other in the circumferential direction, and the case is provided with a partition wall that extends toward the valve body in a portion between the inflow port and the outflow port. A blow-by gas reduction device for an internal combustion engine.

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