JP2016223357A - Oil separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably prevent clogging caused by oil in blow-by gas while securing high recovery efficiency of the oil.SOLUTION: An oil separator comprises: oil separating means 3 that separates oil included in blow-by gas; temperature adjusting means 4 that switchably cools or heats the oil separating means 3; flow rate detecting means 5 that detects a flow rate of the blow-by gas passing through the oil separating means 3; and control means 6 that switches the temperature adjusting means 4 from a cooling state to a heating state on the basis of a detection result of the flow rate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an oil separator used in a blow-by gas reduction device.

  Blow-by gas leaking into the crankcase or the like from the gap between the piston and cylinder of the engine is said to cause deterioration of engine oil, corrosion of metal parts, and air pollution. Therefore, a blow-by gas reduction device that recirculates the leaked blow-by gas to the intake passage side and mixes with the new air-fuel mixture is often provided so that the blow-by gas is not released into the atmosphere in an unburned state.

  The blow-by gas flowing through the reducing device contains oil scattered from engine parts. In particular, in an engine equipped with an exhaust gas recirculation device, blow-by gas is generally sucked upstream from the inlet of the exhaust gas recirculation device, so that oil contained in the blow-by gas flows through the exhaust gas recirculation device. Combined with the soot contained in the flowing gas, it tends to deposit as a deposit in the intake system. This deposit increases the pressure loss of the intake system and decreases the intake air amount, or decreases the heat exchange efficiency of the intake air cooling device, and may cause problems such as a decrease in engine output.

  In order to solve this problem, an oil separator may be provided in the flow path of the reducing device, and the oil separator may be used to separate the oil in the blow-by gas. The oil in blow-by gas is in the form of a mist. Therefore, for example, as shown in Patent Document 1, oil is condensed by cooling the oil separator or blow-by gas, thereby increasing the collection rate of the oil separator (see Paragraph 0008 of Patent Document 1).

  In this way, when the oil separator or blow-by gas is cooled, the water and oil contained in the blow-by gas form a highly viscous emulsion, or the water freezes, causing clogging in the oil separator flow path. The breather function of the reducing device may be impaired.

  As a countermeasure against this clogging, in the configuration of Patent Document 1, a temperature control means for both cooling and heating that can be heated as well as cooling is adopted, and the temperature of the blow-by gas measured by the temperature sensor provided in the flow path is greatly reduced. When this occurs, the blow-by gas is heated to prevent moisture in the blow-by gas from freezing and blocking the flow path (see paragraph 0008 of Patent Document 1). Further, for example, in the configuration of Patent Document 2, it is possible to detect clogging of the crank chamber positively ventilated valve due to freezing or sludge by measuring the pressure of blow-by gas in the crankcase. Can be checked at an appropriate timing (see paragraph 0020 of Patent Document 2).

See JP-A-10-299450 Japanese Patent No. 5282774

  In the configuration of Patent Document 1, cooling or heating of the blow-by gas is performed based on the measurement result of the temperature sensor. However, even if the temperature of the blow-by gas is significantly reduced, clogging due to moisture freezing is necessarily generated. Not necessarily. In spite of no clogging, when the blow-by gas is heated, there is a problem that the oil recovery efficiency is lowered. Further, in the configuration of Patent Document 2, although the clogging of the crank chamber positive ventilation type valve can be detected, since there is no means for eliminating the clogging, it is necessary to perform maintenance each time, which is very complicated.

  Accordingly, an object of the present invention is to reliably prevent clogging caused by the oil while ensuring high recovery efficiency of the oil in the blow-by gas.

  In order to solve the above problems, in the present invention, an oil separation means for separating oil contained in blow-by gas, a temperature adjusting means for cooling or heating the oil separation means in a switchable manner, and the oil separation means. An oil separator is provided that includes a flow rate detection unit that detects a flow rate of blow-by gas and a control unit that switches the temperature adjustment unit from a cooling state to a heating state based on the detection result of the flow rate.

  In this oil separator, the flow rate detection means calculates the flow rate of the blow-by gas passing through the oil separation means from the differential pressure across the oil separation means, and the calculated flow rate value and It is preferable that the control means switch the system when the calculated flow rate value is larger than the determination value by comparing with a determination value that is a flow rate of blow-by gas determined by the operating state of the engine.

  In the configuration for calculating the flow rate of the blow-by gas from the differential pressure across the oil separation means, the control means counts the heating time when the temperature adjusting means is switched from the cooling state to the heating state. Even when the function and the heating time exceed the first predetermined time, when the calculated flow rate value is larger than the determination value, it is determined that the engine is malfunctioning, while the heating for the first predetermined time is Therefore, it is preferable to have an abnormality determination function that determines that the oil separation means is clogged when the calculated flow rate value is equal to or less than the determination value.

  In the configuration having the abnormality determination function, a determination value that replaces an addition determination value obtained by adding a predetermined value to the determination value with the determination value when the control unit determines that a problem has occurred in the engine. A configuration having an update function is preferable.

  In the configuration having the heating time counting function, the control means heats the oil separation means for a second predetermined time shorter than the first predetermined time, so that the calculated flow rate value is greater than the determination value. When the oil separation means is cooled at the initial cooling temperature, the calculated flow rate value is calculated by heating for a period longer than the second predetermined time and not longer than the first predetermined time. It is preferable to have a cooling temperature adjustment function for determining that the oil separation means is cooled at a revised cooling temperature higher than the cooling temperature when the determination value becomes smaller.

  According to the present invention, by cooling the oil separating means, while securing a high oil collection rate, the oil separating means is heated based on the flow rate of the blowby gas oil separating means, so that it becomes clogged or the like. The trouble which originates can be prevented reliably.

The longitudinal cross-sectional view which shows one Embodiment of the oil separator which concerns on this invention 1 is a configuration diagram showing an application example of the oil separator shown in FIG. 1 to an internal combustion engine. The flowchart which shows the processing flow in the oil separator which concerns on this invention

  An embodiment of an oil separator according to the present invention is shown in FIG. The oil separator 1 is for separating oil contained in blow-by gas leaked into a crankcase or the like from a gap between a piston and a cylinder of the engine E (see FIG. 2). Separator fins as the oil separating means 3 (hereinafter, the same reference numerals as the oil separating means 3), Peltier elements as the temperature adjusting means 4 (hereinafter, the same signs as the temperature adjusting means 4), A differential pressure detection device (hereinafter, the same reference numeral as the flow detection means 5) as the flow rate detection means 5, and an electronic control unit (hereinafter, the same reference numeral as the control means 6) as the control means 6. .) As a major component.

  The separator body 2 has a gas inlet 2a for introducing blow-by gas at one end, an oil outlet 2b for discharging oil separated from the blow-by gas at the other end, and a gas exhaust for discharging blow-by gas separated from oil at the wall surface side. Each of the outlets 2c is a hollow member.

  The separator fin 3 is provided between the gas inlet 2a in the separator main body 2, the oil outlet 2b, and the gas outlet 2c, and the blow-by gas introduced from the gas inlet 2a is inside thereof. A labyrinth flow path (a specific flow path shape is not shown in FIG. 1) is formed. The shape of the labyrinth flow path (the length, width, etc.) of the labyrinth flow path can be appropriately determined in consideration of specifications such as the engine displacement.

  The Peltier element 4 is provided close to the separator fin 3 so as to surround it. The terminal of the Peltier element 4 is connected to a power source 7 controlled by the electronic control unit 6, and the separator fin 3 can be freely cooled or heated by switching the polarity of the power source 7. This Peltier element 4 is an example, and if the separator fin 3 can be cooled or heated in a switchable manner, other temperature adjusting means can be appropriately employed instead of the Peltier element 4. In addition, unlike the Peltier element 4, one element does not necessarily have both functions of cooling and heating, and cooling and heating can be performed by separate devices (elements).

  The differential pressure detecting device 5 detects the gas pressures on the gas inlet 2a side and the gas outlet 2c side of the separator fin 3 in the separator body 2 and derives the differential pressure, thereby passing through the separator fin 3. Calculate the flow rate of blow-by gas. As shown in FIG. 1, a configuration may be adopted in which a crankcase internal pressure detection device 8 that detects the internal pressure of the crankcase of the engine E is provided together with or in place of the differential pressure detection device 5. it can. Since the amount of blow-by gas generated can be estimated by measuring the internal pressure of the crankcase, the differential pressure before and after the separator fin 3 (the flow rate of blow-by gas flowing through the separator fin 3) can be estimated from this estimation result. is there.

  The electronic control unit 6 is referred to as a predetermined flow rate (hereinafter referred to as a predetermined value), which is a flow rate calculated from the differential pressure and an estimated flow rate of blow-by gas generated corresponding to the vehicle running state (engine operating speed, load information, etc.). ). Based on the magnitude relationship between the calculated flow rate and the predetermined value, the polarity of the power source 7 connected to the Peltier element 4 (whether the separator fin 3 is cooled or heated) is determined. The predetermined value corresponding to the traveling state of the vehicle is stored in advance in the storage device of the electronic control unit 6 as a database.

  The blow-by gas fed into the oil separator 1 contains moisture (water vapor) in addition to mist-like oil. If the oil and water are mixed and cooled, the separator fins 3 may be clogged due to formation of a highly viscous emulsion or freezing of water.

  When this clogging occurs, the flow rate discharged from the gas discharge port 2c becomes smaller than the flow rate introduced from the gas introduction port 2a, and before and after the passage of the separator fin 3 detected by the differential pressure detection device 5 The differential pressure increases. When this differential pressure increases, the apparent calculated flow rate calculated from the differential pressure increases even though the flow rate actually decreases due to clogging. Therefore, the electronic control unit 6 determines that there is a possibility of clogging when the calculated flow rate becomes larger than the predetermined value, and issues an instruction to switch the polarity of the power source 7 connected to the Peltier element 4.

  When the polarity of the power source 7 is switched, the separator fin 3 is heated by the Peltier element 4. By heating the separator fin 3, the viscosity of the emulsion is lowered and the frozen water is dissolved to eliminate clogging. When this clogging is eliminated and the calculated flow rate becomes smaller than the predetermined value, the polarity of the power source 7 is switched again by the electronic control unit 6, and the separator fin 3 is cooled by the Peltier element 4.

  On the other hand, when the calculated flow rate is equal to or less than the predetermined value, it can be determined that the blow-by gas having a flow rate corresponding to the traveling state of the vehicle is flowing smoothly through the separator fin 3, so the polarity of the power source 7 is not switched. In addition, the cooling state of the separator fin 3 is maintained.

  Blow-by gas containing mist-like oil is introduced into the separator body 2 from the gas inlet 2 a and passes through the separator fins 3. The separator fin 3 is cooled to a predetermined cooling temperature (for example, 5 ° C.) by the Peltier element 4 during normal operation. For this reason, the blow-by gas is cooled when it passes through the separator fins 3. When the blow-by gas is cooled, the mist-like oil contained therein aggregates and adheres to the separator fin 3. As the amount of adhesion increases, oil drops from the separator fin 3 and is discharged from the oil discharge port 2b. The discharged oil is returned to the oil pan (not shown) of the engine E. The blow-by gas (gas component) from which the oil has been separated is discharged from the gas discharge port 2c and then returned to the intake passage (see reference numeral 11 in FIG. 2).

  The oil separator 1 is employed in, for example, an internal combustion engine E including a dual loop exhaust gas recirculation system shown in FIG. The internal combustion engine E is an automobile engine, and includes an intake passage 11 that leads to an intake port that feeds air-fuel mixture into a cylinder that accommodates a piston, an exhaust passage 12 drawn from the exhaust port, a fuel injection device, and the like. The intake port and the exhaust port are opened and closed by valves.

  The intake passage 11 includes a first throttle valve 13 that adjusts the flow passage area of the intake passage 11 from the intake port toward the upstream side, an intake air cooling device 14 that cools the intake air flowing through the intake passage 11, and a turbocharger compressor. 15. A second throttle valve 16 that adjusts the flow passage area of the intake passage 11, a case 17 that houses an air cleaner, and the like are provided.

  The exhaust passage 12 is provided with a turbine 18 of a turbocharger, an exhaust purification unit 19 including a catalyst for removing nitrogen oxide and the like in the exhaust, and a silencer (muffler) 20 from the exhaust port toward the downstream side. .

  A midway portion between the turbine 18 and the exhaust port of the exhaust passage 12 and a midway portion between the intake port of the intake passage 11 and the first throttle valve 13 are formed by a high pressure exhaust gas recirculation passage 21 constituting the high pressure exhaust gas recirculation device H. Communicate. A part of the exhaust gas discharged from the internal combustion engine E recirculates to the intake passage 11 as recirculation gas via the high-pressure exhaust recirculation passage 21. A high-pressure exhaust gas recirculation valve 22 is provided in the high-pressure exhaust gas recirculation passage 21. The recirculated gas merges with the intake air in the intake passage 11 in accordance with the pressure state in the intake passage 11 that accompanies the opening and closing of the high-pressure exhaust gas recirculation valve 22 and the opening and closing of the first throttle valve 13.

  Further, midway portions of the exhaust purification unit 19 and the silencer 20 in the exhaust passage 12 and midway portions of the compressor 15 and the second throttle valve 16 in the intake passage 11 are low pressures constituting the low pressure exhaust gas recirculation device L. The exhaust gas recirculation passage 23 communicates. A part of the exhaust gas discharged from the internal combustion engine E is recirculated to the upstream side of the intake air cooling device 14 in the intake passage through the low-pressure exhaust recirculation passage 23. The low pressure exhaust gas recirculation passage 23 is provided with a low pressure exhaust gas recirculation valve 24. Then, the recirculated gas merges with the intake air in the intake passage 11 in accordance with the pressure state in the intake passage 11 accompanying the opening and closing of the low pressure exhaust recirculation valve 24 and the opening and closing of the second throttle valve 16. The low pressure exhaust gas recirculation passage 23 of the low pressure exhaust gas recirculation device L is provided with a recirculation gas cooler 25 for cooling the recirculation gas.

  The gas inlet 2 a of the oil separator 1 (separator body 2) is connected to the crankcase of the engine E via a gas inlet pipe 26, while the gas outlet 2 c is connected to the intake passage 11 via a gas outlet pipe 27. It is connected to the. The oil discharge port 2b is connected to an oil pan of the engine E (not shown).

  In FIG. 2, an example in which the oil separator 1 is employed in an internal combustion engine E having a dual-loop exhaust gas recirculation system is shown, but this is merely an example, and the blow-by gas in the crankcase of the engine E is shown. The present invention can be applied to the internal combustion engine E of another aspect that employs a configuration that returns the air to the intake passage 11.

  With reference to the configuration of the oil separator 1 shown in FIG. 1, the operation flow of the oil separator 1 and the processing flow when an abnormality such as clogging occurs in the separator fin 3 will be described using the flowchart shown in FIG.

  In this processing flow, first, the electronic control unit 6 determines the polarity and current value of the power source 7 so that the Peltier element 4 cools the separator fin 3 at a predetermined cooling temperature (for example, 5 ° C.) (FIG. 3). Sign S1). Then, the differential pressure detection device 5 detects the differential pressure from the gas pressure on the gas inlet 2a side and the gas outlet 2c side of the separator fin 3 in the separator body 2 (reference S2 in FIG. 3), and the separator fin 3 The flow rate of the blow-by gas passing through is calculated (reference S3 in FIG. 3).

  Each sensor (not shown) provided in the vehicle detects vehicle travel information such as engine operation speed and load information (reference S4 in FIG. 3). The electronic control unit reads the estimated flow rate of blowby gas corresponding to the vehicle travel information detected by each sensor from the table indicating the relationship between the vehicle travel information recorded in advance and the estimated flow rate of blowby gas. (Refer to S5 in FIG. 3).

  Here, the magnitude relationship between the calculated flow rate value calculated by the differential pressure detection device 5 and the determination value estimated from the vehicle travel information is compared (reference S6 in FIG. 3). When the calculated flow rate value is larger than the judgment value (Y side of symbol S6 in FIG. 3), the separator fin 3 is clogged (formation of oil and water emulsion or water freeze) and compared with the actual flow rate. Since the apparent flow rate may increase, the polarity of the power supply 7 is switched, and the separator fin 3 is heated to a predetermined heating temperature (for example, 100 ° C.) by the Peltier element 4 (reference numeral in FIG. 3). S7). When clogging occurs due to the formation of emulsion or freezing of moisture, the emulsion disappears by this heating, or the frozen water is dissolved and clogging is eliminated. Note that the comparison of the magnitude relationship between the calculated flow rate value and the determination value (symbol S6 in FIG. 3) is continuously performed, and it is possible to specify at which timing during the heating the clogging is eliminated. ing.

  The electronic control unit 6 has a heating time counting function for counting the heating time, and starts counting up the heating time at the timing when the Peltier element 4 is switched from the cooling state to the heating state (reference S8 in FIG. 3). The counted heating time is compared with a first predetermined time (eg, 1 minute) (reference S9 in FIG. 3), and even if the heating time exceeds the first predetermined time, the calculated flow rate value is larger than the determination value. When the electronic control unit 6 does not clog the separator fins 3 (Y side of the symbol S9 in FIG. 3), it determines that the flow rate of blow-by gas has actually increased due to deterioration of the engine E (see FIG. 3). Symbol S10 in FIG. If clogging occurs due to emulsion formation or moisture freezing, it can usually be resolved by heating for 1 minute. If the apparent flow rate is still large after heating, This is because the possibility of deterioration is high.

  When it is determined that the engine E is deteriorated, an engine deterioration flag is set and flag information is stored in the electronic control unit 6 (reference S11 in FIG. 3). Further, the electronic control unit 6 has a determination value update function for rewriting the determination value as necessary. Upon receiving the engine deterioration determination, an addition determination value obtained by adding a predetermined value to the determination value is used as the original determination value. Rewriting is performed (reference S12 in FIG. 3). Thus, by rewriting the original determination value with the addition determination value, the vehicle can be tentatively run until the next maintenance. The predetermined value to be added may be, for example, a value obtained by adding a predetermined margin to a value obtained by subtracting the original determination value from the current flow rate value. The rewritten determination value can be manually returned to the original determination value after the engine deterioration maintenance is completed and the engine deterioration flag is deleted.

  As described above, the electronic control unit 6 is provided with an abnormality determination function that distinguishes between the clogging of the separator fins 3 and the deterioration of the engine E, thereby promptly handling maintenance when the engine E deteriorates. It can be carried out.

  When the rewriting of the determination value is completed, the heating time counter is reset (reference S13 in FIG. 3), and the process is returned (reference S14 in FIG. 3).

  The counted heating time is compared with the first predetermined time (reference S9 in FIG. 3), and the calculated flow rate value becomes equal to or less than the determination value before the heating time reaches the first predetermined time (in FIG. 3). It is determined that the increase in the differential pressure in the separator fin 3 is due to clogging of the separator fin 3 (reference numeral S15 in FIG. 3).

  At this time, the heating time is further compared with a second predetermined time (for example, 45 seconds) shorter than the first predetermined time (reference S16 in FIG. 3), and when the heating time is longer than the second predetermined time ( 3 is determined that an emulsion is likely to be formed by cooling at the current cooling temperature (reference S17 in FIG. 3). In this case, the cooling temperature adjusting function of the electronic control unit 6 changes the cooling temperature of the separator fin 3 to a revised cooling temperature (for example, 10 ° C.) higher than the original cooling temperature (reference S18 in FIG. 3). Thus, by changing the cooling temperature, it is possible to prevent the formation of emulsion and the freezing of water as much as possible while cooling the separator fin 3 while collecting the oil. The temperature change width from the original cooling temperature to the revised cooling temperature (plus 5 ° C. in the above example) is appropriately determined as long as the oil recovery efficiency is not hindered.

  When the change of the cooling temperature is completed, the heating time counter is reset (reference S19 in FIG. 3), and the process is returned (reference S14 in FIG. 3).

  The magnitude relationship between the calculated flow rate value and the determination value is compared (reference S6 in FIG. 3). When the calculated flow value is equal to or less than the determination value (N side of reference S6 in FIG. 3), Since it can be determined that the blow-by gas of the corresponding flow rate is flowing smoothly through the separator fin 3, the cooling of the separator fin 3 is maintained at the original cooling temperature (reference S22 in FIG. 3).

  The above embodiment is merely an example, and as long as the problem of the present invention of reliably preventing clogging caused by this oil can be solved while ensuring high recovery efficiency of oil in blow-by gas, The arrangement of the components of the separator 1, the first predetermined time, the second predetermined time, and the like can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1 Oil separator 2 Separator main body 2a Gas inlet 2b Oil outlet 2c Gas outlet 3 Oil separation means (separator fin)
4 Temperature control means (Peltier element)
5 Flow rate detection means (Differential pressure detection device)
6 Control means (electronic control unit)
7 Power supply 11 Intake passage 12 Exhaust passage 13 First throttle valve 14 Intake cooling device 15 Compressor 16 Second throttle valve 17 Case 18 Turbine 19 Exhaust purification unit 20 Silencer 21 High pressure exhaust recirculation passage 22 High pressure exhaust recirculation valve 23 Low pressure exhaust Reflux passage 24 Low pressure exhaust recirculation valve 25 Reflux gas cooler 26 Gas introduction pipe 27 Gas exhaust pipe E Engine H High pressure exhaust gas recirculation device L Low pressure exhaust gas recirculation device

Claims (5)

Oil separation means for separating oil contained in blowby gas;
Temperature control means for cooling or heating the oil separation means in a switchable manner;
Flow rate detection means for detecting the flow rate of blow-by gas passing through the oil separation means;
Control means for switching the temperature adjusting means from a cooling state to a heating state based on the detection result of the flow rate;
Oil separator equipped with.   The flow rate detection means calculates the flow rate of the blowby gas passing through the oil separation means from the differential pressure across the oil separation means, and depends on the calculated flow rate value calculated and the operating condition of the engine. 2. The oil separator according to claim 1, wherein the control unit performs switching when the calculated flow rate value is larger than the determination value by comparing with a determination value that is a determined flow rate of blow-by gas.   The control means counts the heating time when the temperature adjusting means is switched from the cooling state to the heating state, and even if the heating time exceeds a first predetermined time, the calculated flow rate value is When it is determined that the engine is malfunctioning when the value is larger than the determination value, the oil separation means is turned on when the calculated flow rate value becomes equal to or less than the determination value due to the heating for the first predetermined time. The oil separator according to claim 2, further comprising: an abnormality determination function that determines that clogging has occurred.   4. The oil according to claim 3, further comprising: a determination value update function that replaces an addition determination value obtained by adding a predetermined value to the determination value with the determination value when the control unit determines that a problem has occurred in the engine. Separator.   When the control means heats the oil separation means for a second predetermined time shorter than the first predetermined time, and the calculated flow rate value becomes smaller than the determination value, the oil separation means is While it is determined that the cooling is performed at the initial cooling temperature, when the calculated flow rate value is smaller than the determination value by heating for the first predetermined time longer than the second predetermined time, The oil separator according to claim 3 or 4, wherein the oil separator has a cooling temperature adjustment function for determining that the oil separation means is cooled at a revised cooling temperature higher than the cooling temperature.

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