JP6565749B2 - Electrostatic collection type oil mist separator and control device for electrostatic collection type oil mist separator - Google Patents

Description

  The present invention relates to an electrostatic collection type oil mist separator that introduces blow-by gas of an internal combustion engine into a case, separates it from oil mist, and discharges the separated oil component outside the case, and a control device therefor.

  The internal combustion engine is provided with a return passage for returning the blow-by gas in the crank chamber to the intake passage. An oil mist separator that separates oil mist contained in blow-by gas is provided in the middle of such a reflux passage (see, for example, Patent Document 1).

  In the case of the oil semistopper described in Patent Document 1, two net-like electrodes are arranged to face each other, and a potential difference is applied to these electrodes by a power supply device. According to such an oil separator, when blow-by gas passes through one electrode, moisture contained in the blow-by gas is charged. The charged moisture is adsorbed to the other electrode by electrostatic force. At this time, the oil mist contained in the blow-by gas is adsorbed to the electrode together with moisture. In this way, oil mist contained in blow-by gas is separated. Note that the oil component and water component adsorbed on the electrode fall by their own weight and are discharged out of the case through an oil discharge port formed in the bottom wall of the case.

Japanese Patent Laid-Open No. 3-141811

  By the way, in the case of the oil mist separator described in Patent Document 1, when the flow rate of blow-by gas is large, the oil does not collide with the electrode and easily passes through the electrode. Therefore, it is difficult to collect oil mist efficiently.

  On the other hand, in the oil separator, it is conceivable to make the oil mist easily collide with the electrode by making the mesh of the electrode fine. However, in this case, the resistance to ventilation is increased by making the mesh of the electrode finer, resulting in a contradiction that the pressure loss due to the oil mist separator increases.

  The objective of this invention is providing the control apparatus of the electrostatic collection type oil mist separator which can collect oil mist efficiently, and an electrostatic collection type oil mist separator.

  An electrostatically collecting oil mist separator for achieving the above object is formed of a plurality of electrode plates arranged opposite to each other and an electrically insulating material, and is interposed between the facing surfaces of the plurality of electrode plates. A collecting unit having a filter; a case that houses the collecting unit; and a voltage generator that applies a voltage between the plurality of electrode plates to apply a potential difference, and the potential difference is applied between the plurality of electrode plates. In this state, the blow-by gas of the internal combustion engine is introduced into the case and allowed to pass through the filter, whereby oil mist contained in the blow-by gas is separated by electrostatic adsorption force and the separated oil component is Discharge outside the case. The filter has a plurality of filter main body portions provided at intervals in the flow direction of the blow-by gas, and a filter connecting portion that connects a part of the plurality of filter main body portions, and the electrode plate Are provided such that gaps adjacent to each other in the facing direction of the plurality of electrode plates are formed with respect to gaps formed between the plurality of filter main body portions.

  By applying a potential difference between the electrode plates by the voltage generator, an electrostatic field is generated between the electrode plates, and the surface of the filter (or the surface of the fiber if the filter is made of fibers) is positive due to dielectric polarization. Or a negative charge is generated. For this reason, the charged oil mist included in the blowby gas is bent in the moving direction by electrostatic force when passing between the electrode plates, and is easily captured by the filter.

  Moreover, when the oil mist contained in the blow-by gas is not charged, it passes through the filter gap (the gap between the fibers when the filter is made of fibers) interposed between the electrode plates. Dielectric polarization causes a positive or negative charge on the surface of the oil mist. For this reason, such oil mist is also attracted to negative or positive charges generated on the surface of the filter by electrostatic force, and is easily captured by the filter.

For these reasons, oil mist can be captured effectively even with a coarse filter, and an increase in ventilation resistance due to the filter can be suppressed.
Here, blow-by gas greatly influences the electrostatic field when flowing into a filter that is sandwiched between the electrode plates and affected by the electrostatic field from a space that is not sandwiched between the electrode plates and is not easily affected by the electrostatic field. receive. At this time, since the moving direction of the oil mist is greatly bent, the oil mist is easily captured by the filter.

  According to the said structure, blowby gas will flow in into a filter main-body part in multiple times from the space not pinched by the electrode plate. For this reason, the frequency with which the moving direction of the oil mist is greatly bent can be increased, and the oil mist is easily captured by the filter.

  Also, according to the above configuration, since the plurality of filter main body portions are connected by the filter connecting portion, the component of the oil mist separator is different from the configuration in which the plurality of filters are arranged at intervals in the flow direction of the blowby gas. An increase in the score can be avoided.

  In addition, a control device for an electrostatically collecting oil mist separator for achieving the above object is applied to the electrostatically collecting oil mist separator, and controls to control a voltage application mode to the plurality of electrode plates. It is an apparatus, Comprising: The control part which variably sets the application aspect of the voltage to the said several electrode plate according to an engine operating state is provided.

  According to this configuration, it is possible to set the mode of voltage application to the plurality of electrode plates according to the engine operating state having a correlation with the flow rate of the blowby gas at that time. Therefore, it is possible to suppress the voltage from being applied to the electrode plate more than necessary, and to reduce power consumption.

  According to the present invention, oil mist can be collected efficiently.

The perspective view which shows the whole oil mist separator about one Embodiment of an electrostatic collection type oil mist separator. The perspective view which shows the collection unit of the embodiment. The wiring diagram which shows the electrical connection aspect of the several electrode plate and voltage generator of the embodiment. The electric circuit diagram centering on the voltage generator of the embodiment. The schematic diagram for demonstrating the effect | action of an oil mist separator. The graph which shows the relationship between the flow volume of blow-by gas of the same embodiment, and an applied voltage. The perspective view which shows the collection unit of a modification.

Hereinafter, an embodiment will be described with reference to FIGS.
<Oil mist separator 10>
As shown in FIG. 1, the oil mist separator 10 is provided in a recirculation passage for recirculating blowby gas in a crank chamber of an in-vehicle internal combustion engine to an intake passage, and is made of an electrically insulating synthetic resin material such as nylon 66, for example. It has a case 11 formed.

  The case 11 includes a case main body 20 having an opening in the upper portion and a lid body 26 that closes the opening of the case main body 20. The case main body 20 has a bottom wall 22 and a side wall 21 that are rectangular in plan view. In the following description, the longitudinal direction of the bottom wall 22 is simply referred to as the longitudinal direction.

  On the side wall 21 on one end side in the longitudinal direction, a cylindrical introduction port 23 that communicates the inside and outside of the case 11 protrudes outward. In addition, a cylindrical outlet 24 that communicates the inside and outside of the case 11 protrudes outward from the side wall 21 on the other end side in the longitudinal direction. An oil discharge port 25 that communicates the inside and the outside of the case 11 protrudes downward from a position of the bottom wall 22 close to the outlet port 24.

  As shown in FIGS. 1 and 2, a collection unit 30 is accommodated inside the case 11. The collection unit 30 is made of stainless steel, and is made of four electrode plates 40 that are opposed to each other at an interval, and a nonwoven fabric of polyester fibers 50A (see FIG. 5) that is an electrical insulating material. And three filters 50 interposed between the 40 opposing surfaces. An electrically insulating material such as polyester is also a dielectric material in which dielectric polarization occurs.

The electrode plate 40 and the filter 50 have the same side view shape.
That is, as shown in FIGS. 1 to 3, the electrode plate 40 includes two electrode plate main body portions 41 that are rectangular in a side view and spaced apart in the longitudinal direction, that is, the blow-by gas flow direction. It has an electrode plate connecting portion 42 that connects the upper portions of the electrode plate main body portion 41. Accordingly, the central portion of the electrode plate 40 in the longitudinal direction is cut out in a rectangular shape when viewed from the side at a portion below the electrode plate connecting portion 42 (see FIG. 2).

  The filter 50 includes two filter body portions 51 that are rectangular in a side view provided at intervals in the longitudinal direction, and a filter connection portion 52 that connects upper portions of the two filter body portions 51. Accordingly, the central portion of the filter 50 in the longitudinal direction is cut out in a rectangular shape when viewed from the side at a portion below the filter connecting portion 52 (see FIG. 2).

  Further, the entire side surfaces of the two filter main body portions 51 constituting the filter 50 are in contact with the two electrode plate main body portions 41 constituting the electrode plate 40, respectively, and the entire side surface of the filter connecting portion 52 is the electrode plate connecting portion 42. Abut. In other words, the entire side surface of the filter 50 is in contact with the opposing surfaces of a pair of adjacent electrode plates 40.

  As shown in FIG. 3, in the electrode plate 40, a gap S <b> 2 adjacent in the facing direction W of the plurality of electrode plates 40 is formed with respect to the gap S <b> 1 formed between the two filter main bodies 51 constituting the filter 50. It is provided to be.

  The collection unit 30 is disposed at a distance from the side wall 21 in which the introduction port 23 is formed (not shown). Moreover, the collection unit 30 is arrange | positioned at intervals with respect to the side wall 21 in which the outlet 24 was formed (refer FIG. 1).

<Voltage generator 60 and electronic controller 80>
As shown in FIG. 3, the voltage generator 60 is electrically connected to each electrode plate 40 which comprises the collection unit 30 via the conducting wire. The anode (+) of the voltage generator 60 is connected to the odd-numbered electrode plates 40 from the left in FIG. In addition, the negative electrode (−) of the voltage generator 60 is connected to the even-numbered electrode plates 40 from the left in FIG.

The voltage generator 60 can apply a potential difference between the adjacent electrode plates 40 of the collection unit 30.
As shown in FIG. 4, an in-vehicle DC power supply (hereinafter referred to as power supply 61) includes a primary coil 63 for boosting transformer 62, a field effect transistor (hereinafter referred to as FET 64) as a switching element in this example, and an overcurrent detection function. The detection resistors 66 are sequentially connected in series. A first drive circuit 65 for switching and driving the FET 64 is connected to the gate terminal of the FET 64.

  A diode 69 and the electrode plate 40 of the collection unit 30 are connected in series to the secondary coil 68 of the transformer 62. A smoothing capacitor 70 is connected to the secondary coil 68.

  The first drive circuit 65 has a comparison circuit that compares the voltage V of the detection resistor 66 with the limit value Vmax. When the voltage V of the detection resistor 66 becomes equal to or higher than the limit value Vmax, the first drive circuit 65 The FET 64 is turned off when an overcurrent caused by a short circuit flows. Thereby, application of a potential difference between the electrode plates 40 is stopped.

  A voltage dividing circuit 71 is connected between the output line La connecting the diode 69 and the collection unit 30 and the ground. The divided voltage output of the voltage dividing circuit 71 is input to the second drive circuit 67.

  The second drive circuit 67 changes the voltage application mode to the collection unit 30 by controlling the first drive circuit 65 based on the divided voltage output of the voltage divider circuit 71. In addition, an electronic control unit 80 is connected to the second drive circuit 67.

  The electronic control unit 80 controls the operation of the internal combustion engine, and temporarily stores a central processing control unit (CPU), a read-only memory (ROM) in which various programs and maps are stored in advance, and a calculation result of the CPU. A random access memory (RAM), a timer counter, an input interface, an output interface, and the like are provided.

  The electronic control unit 80 receives detection signals from various sensors for detecting the engine operating state. Such sensors include an engine speed sensor that detects the engine speed NE, an accelerator sensor that detects the accelerator pedal operation amount ACCP, a throttle sensor that detects the throttle valve opening TA, and an intake air amount GA. There are an air flow meter, a water temperature sensor for detecting the temperature T of the engine cooling water, and the like.

  The electronic control device 80 includes a control unit 81 that variably sets a voltage application mode to each electrode plate 40 of the collection unit 30 according to an engine operating state such as the engine rotation speed NE and the engine load KL. In the present embodiment, as the engine load KL, a ratio “GA / between the intake air amount GA at that time and the maximum intake air amount GAmax that is the maximum value of the intake air amount obtained at the engine rotational speed NE at that time. GAmax "is used.

As the flow rate of the blow-by gas introduced into the case 11 increases, the oil mist separator 10 is required to have a higher collection capability.
Therefore, as shown in FIG. 6, the control unit 81 of the present embodiment sets the voltage applied to each electrode plate 40 to be smaller as the flow rate of blow-by gas introduced into the case 11 is smaller. .

  For example, when the engine 81 is in an engine operating state in which the blow-by gas introduced into the case 11 has a low flow rate, such as during low load low rotation or idle operation, the control unit 81 has a high flow rate of blow-by gas during high load high rotation. The voltage applied to each electrode plate 40 is set smaller than in the engine operating state.

Further, the control unit 81 stops the application of voltage to all the electrode plates 40 when idling of the internal combustion engine is stopped.
Next, the operation of the oil mist separator 10 will be described.

As shown in FIG. 1, the blow-by gas introduced into the case 11 through the inlet 23 flows toward the outlet 24.
By applying a potential difference between the electrode plates 40 by the voltage generator 60, as shown in FIG. 5, an electrostatic field is generated between the electrode plates 40, and on the surface of the fiber 50A of the filter 50, Dielectric polarization causes a positive (+) or negative (-) charge. For this reason, the charged oil mist M contained in the blow-by gas is bent in the moving direction by the electrostatic force when passing between the electrode plates 40, and is easily captured by the filter 50.

  In addition, the oil mist M contained in the blow-by gas is not charged, and oil mist is caused by dielectric polarization when passing through the gap between the fibers 50A of the filter 50 interposed between the electrode plates 40. A positive (+) or negative (-) charge is generated on the surface of M. For this reason, the oil mist M is also attracted to the negative (−) or positive (+) charge generated on the surface of the fiber 50 </ b> A of the filter 50 by electrostatic force, and is easily captured by the filter 50.

For these reasons, the oil mist M can be effectively captured even with the coarse filter 50, and an increase in ventilation resistance due to the filter 50 can be suppressed.
The blow-by gas from which the oil mist M has been separated flows out to the reflux passage through the outlet 24. On the other hand, the oil component accumulated on the bottom wall 22 moves along the bottom wall 22 and is discharged out of the case 11 through the oil discharge port 25.

  Here, when the blow-by gas flows into the filter 50 sandwiched between the electrode plates 40 and affected by the electrostatic field from a space that is not sandwiched between the electrode plates 40 and is not easily affected by the electrostatic field, It is greatly affected. At this time, since the moving direction of the oil mist M is greatly bent, the oil mist M is easily captured by the filter 50.

  In the present embodiment, blow-by gas flows twice into the filter main body 51 from a space not sandwiched between the electrode plates 40. For this reason, the frequency with which the moving direction of the oil mist M is greatly bent can be increased, and the oil mist M is easily captured by the filter 50.

According to the electrostatic collecting oil mist separator and the electrostatic collecting oil mist separator control device according to the present embodiment described above, the following effects can be obtained.
(1) The filter 50 includes two filter main body portions 51 provided at intervals in the blow-by gas flow direction, and a filter connecting portion 52 that connects a part of the two filter main body portions 51 to each other. . The electrode plate 40 is provided such that a gap S2 adjacent in the facing direction W of the plurality of electrode plates 40 is formed with respect to the gap S1 formed between the two filter main body portions 51.

  According to such a configuration, blow-by gas flows into the filter main body 51 twice from the space not sandwiched between the electrode plates 40. For this reason, the frequency with which the moving direction of the oil mist is greatly bent can be increased, and the oil mist is easily captured by the filter.

  In addition, since the two filter main body portions 51 are connected by the filter connecting portion 52, unlike the configuration in which two filters are arranged at an interval in the flow direction of the blow-by gas, the number of filters 50 increases. An increase in the number of parts of the oil mist separator 10 can be avoided.

Therefore, oil mist can be collected efficiently. Therefore, the applied voltage required for collecting oil mist can be lowered, and the power consumption can be reduced.
(2) The electrode plate 40 is provided in contact with two electrode plate main body portions 41 that are provided at intervals in the flow direction of the blow-by gas and respectively contact the side surfaces of the two filter main body portions 51 and the side surface of the filter connecting portion 52. An electrode plate connecting portion 42 that contacts and connects the two electrode plate main body portions 41 to each other is provided.

  According to such a configuration, unlike the configuration in which two electrode plates are arranged at intervals in the blow-by gas flow direction, an increase in the number of electrode plates 40, that is, an increase in the number of parts of the oil mist separator 10 is avoided. it can. Further, since the number of electrode plates 40 does not increase, it is possible to avoid the complexity of wiring, and the configuration of the voltage generator 60 can be simplified. Therefore, the configuration of the oil mist separator 10 can be simplified.

(3) The filter connecting portion 52 connects the upper portions of the two filter main body portions 51.
The blow-by gas flowing inside the case 11 contains more oil mist as it goes downward.

  According to the above configuration, since the filter connecting portion 52 connects the upper portions of the two filter main body portions 51, the gap S1 between the two filter main body portions 51 is formed in the lower portion. For this reason, oil mist can be collected efficiently.

(4) The electronic control unit 80 includes a control unit 81 that variably sets the mode of voltage application to the plurality of electrode plates 40 according to the engine operating state.
According to such a configuration, it is possible to set the mode of voltage application to the plurality of electrode plates 40 according to the engine operating state having a correlation with the flow rate of the blowby gas at that time. Therefore, it is possible to suppress the voltage from being applied to the electrode plate 40 more than necessary, and to reduce power consumption.

  (5) The controller 81 is applied to the plurality of electrode plates 40 when the engine is in an engine operating state where the flow rate of blow-by gas introduced into the case 11 is small compared to when the engine is operating with a high flow rate of the blow-by gas. Reduce the voltage to be applied.

  According to such a configuration, it is possible to suppress an unnecessarily large voltage from being applied when the flow rate of blow-by gas is small. Therefore, it is possible to reduce power consumption while effectively collecting oil mist.

(6) The controller 81 stops the application of voltage to all the electrode plates 40 when idling of the internal combustion engine is stopped.
When idling is stopped, blow-by gas is not introduced into the case 11. According to the above configuration, useless power consumption can be suppressed and power consumption can be further reduced.

<Modification>
In addition, the said embodiment can also be changed as follows, for example.
The control unit 81 estimates the flow rate of blow-by gas introduced into the case 11 based on detection signals from various sensors for detecting the engine operating state, and applies to each electrode plate 40 based on the estimation result. The applied voltage may be variably set.

The voltage applied to each electrode plate 40 can be set to a fixed value regardless of the engine operating state.
-The electrode plate 40 which comprises the collection unit 30 should just be 2 or more, and can change the number of the electrode plates 40 arbitrarily. Moreover, the filter 50 which comprises the collection unit 30 should just be 1 or more sheets.

  -The filter connection part 52 may connect the center part in the up-down direction of the two filter main-body parts 51. FIG. Moreover, the filter connection part 52 may connect the lower parts of the two filter main-body parts 51. FIG. Further, the filter connecting part 52 may connect the upper part of one filter main body part 51 and the lower part of the other filter main body part 51.

  As shown in FIG. 7, the two electrode plates 140 may be provided at intervals in the blow-by gas flow direction. In this case, each electrode plate 140 contacts the side surface of the filter body 51.

  -A filter may have three or more filter main-body parts at intervals in the flow direction of blow-by gas. The same applies to the electrode plate.

  DESCRIPTION OF SYMBOLS 10 ... Oil mist separator, 11 ... Case, 20 ... Case main body, 21 ... Side wall, 22 ... Bottom wall, 23 ... Inlet port, 24 ... Outlet port, 25 ... Oil discharge port, 26 ... Cover body, 30 ... Collection unit 40, 140 ... electrode plate, 41 ... electrode plate main body, 42 ... electrode plate connecting portion, 50 ... filter, 50A ... fiber, 51 ... filter main body portion, 52 ... filter connecting portion, 60 ... voltage generator, 61 ... Power source 62 ... Transformer 63 ... Primary coil 64 ... FET 65 ... First drive circuit 66 ... Detection resistor 67 ... Second drive circuit 68 ... Secondary coil 69 ... Diode 70 ... Capacitor 71 ... Voltage dividing circuit, 80... Electronic control device (control device), 81.

Claims (5)

A collection unit having a plurality of electrode plates arranged opposite to each other, and a filter formed of an electrically insulating material and interposed between the opposed surfaces of the plurality of electrode plates, and a case for housing the collection unit And a voltage generating device that applies a voltage between the plurality of electrode plates to apply a potential difference, and introduces blow-by gas of the internal combustion engine into the case in a state where the potential difference is applied between the plurality of electrode plates. An electrostatic collection type oil mist separator that separates oil mist contained in blow-by gas by electrostatic adsorption force and discharges the separated oil component to the outside of the case by passing through the filter. ,
The filter has a plurality of filter main body portions provided at intervals in the flow direction of the blow-by gas, and a filter connecting portion that connects a part of the plurality of filter main body portions,
The electrode plate is provided such that gaps adjacent to each other in the facing direction of the plurality of electrode plates are formed with respect to gaps formed between the plurality of filter main body portions.
Electrostatic collection type oil mist separator. The electrode plates are provided with a plurality of electrode plate main body portions that are provided at intervals in the flow direction of the blow-by gas and respectively contact the side surfaces of the plurality of filter main body portions, and a plurality of electrode plate main body portions that contact the side surfaces of the filter connecting portions. An electrode plate connecting portion for connecting the electrode plate main body portions of each other,
The electrostatic collection type oil mist separator according to claim 1. The filter connecting portion connects upper portions of the plurality of filter main body portions,
The electrostatic collection type oil mist separator according to claim 1 or 2. A control device that is applied to the electrostatically collecting oil mist separator according to any one of claims 1 to 3, and that controls a voltage application mode to the plurality of electrode plates,
A control unit that variably sets the application mode of the voltage to the plurality of electrode plates according to the engine operating state,
Control device for electrostatic collection type oil mist separator. The controller is configured to apply a voltage to be applied to the plurality of electrode plates when the engine is in an engine operating state where the flow rate of blow-by gas introduced into the case is small compared to when the engine is operating with a large flow rate of the blow-by gas. Make it smaller,
The control apparatus of the electrostatic collection type oil mist separator of Claim 4.