JP2012007589A - Blow-by gas reducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that an engine oil deposited on a wall surface in an oil separator is aggregated by an nitric acid generated in the oil separator and is accumulated in the oil separator as a sludge.SOLUTION: The blow-by gas reducing device includes: a blow-by gas collection passage 31 for directing a blow-by gas from a crank chamber 19 to an intake passage 25a; an inlet port 32a that is disposed midway in the blow-by gas collection passage 31 and is connected with an upstream of the blow-by gas collection passage 31; an outlet port 32b that is connected with an downstream of the blow-by gas collection passage 31; a filter 38 that is disposed to separate the inlet port 32a from the outlet port 32b and that catches the engine oil 16 included in the blow-by gas; and the oil separator 32 having an oil collection port 32c for directing the engine oil 16 caught by the filter 38 to the crank chamber 19. The filter 38 of the oil separator 32 is disposed so that it includes an oil aggregation preventing member and covers the inlet port 32a.

Description

  The present invention relates to a blow-by gas reduction device for sending blow-by gas blown into a crankcase from a combustion chamber of an internal combustion engine back to an intake system.

  The blow-by gas reduction device sends the unburned mixture that blows from the combustion chamber of the internal combustion engine through the gap between the cylinder and piston into the crank chamber, that is, blow-by gas is sent back to the intake system so that it is not discharged into the atmosphere. Is for. In this blow-by gas reduction device, when the blow-by gas intervening in the crank chamber is sent back to the intake system, the blow-by gas contains mist-like engine oil, which is removed by an oil separator (oil mist separator). There is a need to. Patent Document 1 discloses a technique related to such an oil separator.

By the way, when the moisture contained in the blow-by gas is captured by the filter of the oil mist separator, the moisture reacts with the nitrogen oxides NO _x contained in the blow-by gas to generate nitric acid. Furthermore, the engine oil trapped in the filter is agglomerated by the nitric acid and becomes sludge, which causes clogging of the filter. For this reason, in Cited Document 1, a neutralizing agent for neutralizing an acidic substance such as nitric acid, for example, calcium carbonate, is applied to the filter of the oil mist separator, and the acidic substance is neutralized by the neutralizing agent. Sludge generation is prevented.

JP 2009-275670 A

  In the oil separator disclosed in the cited document 1, a part of the neutralizing agent applied to the surface of the filter is covered with an oil film of engine oil, and this neutralizing agent reacts efficiently with acidic substances. May be difficult to do. As a result, there arises a problem that engine oil adhering to the wall surface in the oil separator is agglomerated by nitric acid generated in the oil separator and becomes sludge and accumulates in the oil separator.

[Object of invention]
An object of the present invention is to provide a blow-by gas reduction device capable of suppressing the generation of sludge accumulated in an oil mist separator as compared with the conventional one.

A blow-by gas reduction device according to the present invention includes a blow-by gas recovery passage that guides blow-by gas from a crank chamber of the internal combustion engine to an intake passage of the internal combustion engine,
Provided in the middle of this blow-by gas recovery passage, an inlet port connected to the upstream side of the blow-by gas recovery passage, an outlet port connected to the downstream side of the blow-by gas recovery passage, and the inlet port and the outlet port are partitioned A blow-by comprising an oil separator having a filter arranged so as to capture oil contained in blow-by gas and an oil recovery port for guiding the oil captured by the filter to the crank chamber side of the internal combustion engine A gas reduction device,
The filter of the oil separator includes an oil aggregation preventing member and is arranged so as to cover the inlet port.

  In the present invention, the blow-by gas interposed in the crank chamber is returned from the blow-by gas recovery passage to the intake passage. The mist-like engine oil contained in the blow-by gas is captured by a filter of an oil separator provided in the middle of the blow-by gas recovery passage. In this case, since the filter including the oil aggregation preventing member is disposed so as to cover the inlet port of the oil separator, the engine oil is captured without flowing into the oil separator, and the oil is recovered without being aggregated. It is discharged from the port toward the crank chamber.

  The blow-by gas reduction apparatus according to the present invention may further include a heating means for heating the blow-by gas flowing into the inlet port of the oil separator. In this case, it is possible to further comprise temperature detecting means for detecting the temperature of the blow-by gas flowing through the blow-by gas recovery passage and control means for controlling the operation of the heating means based on the temperature detected by the temperature detecting means. .

  The oil aggregation preventing member may include an ion exchange resin that adsorbs a conjugate base of a substance that exhibits acidity by reacting with moisture contained in blow-by gas.

  An oil separator can be provided in the cylinder head cover of the internal combustion engine or in contact with the cylinder block, or an oil separator can be disposed in the blow-by gas recovery passage between the cam chamber and the intake passage.

  According to the blow-by gas reduction device of the present invention, since the filter of the oil separator includes the oil aggregation preventing member and is arranged so as to cover the inlet port, before the mist-like engine oil flows into the oil separator, This can be captured by a filter. At the same time, even if a component that promotes oil aggregation is included in the blow-by gas, the engine oil captured by the filter is discharged from the oil recovery port to the crank chamber without being aggregated by the oil aggregation preventing member. . As a result, engine oil does not remain in the oil separator, and sludge generation can be suppressed.

  When the heating means for heating the blow-by gas flowing into the inlet port of the oil separator is provided, condensation of water vapor contained in the blow-by gas can be prevented. As a result, it is possible to return water vapor to the intake system together with the blow-by gas passing through the oil separator, and it is possible to prevent adverse effects due to moisture being trapped by the filter. Further, in the case of including the temperature detecting means for detecting the temperature of the blow-by gas flowing through the blow-by gas recovery passage and the control means for controlling the operation of the heating means based on the temperature detected by the temperature detecting means, the heating means It is possible to prevent waste due to operation.

When the oil aggregation preventing member includes an ion exchange resin that adsorbs a conjugate base of a substance that exhibits acidity by reacting with moisture contained in the blowby gas, nitric acid is not generated due to the reaction between NO _x contained in the blowby gas and water. Can be prevented. As a result, it is possible to reliably suppress a problem that engine oil is sludged by nitric acid.

It is a conceptual diagram showing the schematic structure of one Embodiment of the internal combustion engine of the spark ignition system incorporating the blowby gas reduction apparatus by this invention. It is a three-dimensional projection figure which represents typically the external appearance of the filter in embodiment shown in FIG. It is a three-dimensional projection figure which represents typically the external appearance of other embodiment of a filter.

  An embodiment in which the blow-by gas reduction device according to the present invention is applied to a spark ignition type multi-cylinder internal combustion engine will be described in detail with reference to FIG. 1 schematically showing the concept. However, the present invention is not limited to such an embodiment, and is directly applied to a compression ignition type internal combustion engine that spontaneously ignites by directly injecting light oil from a fuel injection valve into a combustion chamber in a compressed state. Can do.

  The engine 10 according to this embodiment includes an oil pan 11, a crankcase 12, a cylinder block 13, a cylinder head 14, and a cylinder head cover 15. An oil pan 11 that stores engine oil 16 is attached to one end of a crankcase 12 that houses a crankshaft 17, and one end of a cylinder block 13 that houses a piston 18 is connected to the other end of the crankcase 12. Yes. The oil pan 11, the crankcase 12, the cylinder block 13, and the piston 18 define a crank chamber 19 whose volume is periodically variable as the piston 18 reciprocates. One end side of a cylinder head 14 incorporating a valve mechanism 20 is connected to the other end side of the cylinder block 13. The cylinder block 13, the cylinder head 14, and the piston 18 define a combustion chamber 21, and the volume of the combustion chamber 21 is periodically variable as the piston 18 reciprocates. Further, a cylinder head cover 15 is attached to the other end side of the cylinder head 14, and a cam chamber 22 is defined therebetween.

  The engine 10 is a spark ignition type multi-cylinder internal combustion engine in which fuel such as gasoline, alcohol, a mixture thereof, or liquefied natural gas is injected into the intake port 13a from the fuel injection valve 23 and ignited by the spark plug 24. However, a single cylinder internal combustion engine may be used due to the characteristics of the present invention. Further, instead of the port injection type fuel injection valve 23, a direct injection type in which fuel is directly injected into the combustion chamber 21 may be employed.

  The cylinder head 14 is formed with an intake port 13a and an exhaust port 13b respectively facing the combustion chamber 21. The cylinder head 14 also includes an intake valve 20a that opens and closes the intake port 13a, an exhaust valve 20b that opens and closes the exhaust port 13b, and a valve mechanism 20 that includes the cam 20c that drives the intake valve 20a and the exhaust valve 20b. It has been incorporated. The above-described fuel injection valve 23 and a spark plug 24 for igniting the air-fuel mixture in the combustion chamber 21 are also assembled to the cylinder head 14.

  At the upstream end side of the intake pipe 25 that is connected to the cylinder head 14 so as to communicate with the intake port 13a and defines the intake passage 25a together with the intake port 13a, dust and the like contained in the atmosphere are removed to remove the intake passage 25a. An air cleaner 26 is provided for guiding the air. A throttle valve 28 is incorporated in a portion of the intake pipe 25 between the air cleaner 26 and a surge tank 27 formed in the middle of the intake pipe 25. The throttle valve 28 in the present embodiment is configured to electrically adjust the opening degree of the intake passage 25a via a throttle actuator (not shown) based on a depression amount of an accelerator pedal (not shown) operated by the driver. However, the accelerator pedal and the throttle valve 28 may be mechanically connected. In this case, a throttle actuator or the like is unnecessary.

  The piston 18 accommodated in the cylinder block 13 is connected to the crankshaft 17 attached to the crankcase 12 via a connecting rod 29, and the reciprocating motion of the piston 18 is converted into the rotational motion of the crankshaft 17. That is, the intake air supplied from the intake pipe 25 into the combustion chamber 21 through the air cleaner 26 forms an air-fuel mixture with the fuel injected from the fuel injection valve 23 into the intake port 13a, and is caused by the spark of the ignition plug 24. It ignites and burns, thereby causing the piston 18 to reciprocate.

Crankcase ventilation device 30 in this embodiment is attached to such an engine 10, a blow-by gas collection passage 31, an oil separator 32, the glow plug 33, a temperature sensor 34, ECU (E lectronic C ontrol U nit) 35 and a ventilation passage 36.

  A blowby gas recovery passage 31 that guides the blowby gas from the crank chamber 19 of the engine 10 to the intake passage 25a of the engine 10 is defined by a communication passage 31a formed in the engine 10 and a blowby gas return pipe 31b. The communication path 31 a is formed across the cylinder block 13 and the cylinder head 14 so as to communicate with the crank chamber 19 and the oil separator 32 defined in the cylinder head cover 15. The blow-by gas return pipe 31b connected to the oil separator 32 and the intake pipe 25 has one end connected to the oil separator 32 defined in the cylinder head cover 15 and the other end connected to the surge tank 27 and the throttle valve 28. In the intake passage 25a. For this reason, it should be noted that the blow-by gas recovery passage 31 and the oil separator 32 are in a negative pressure state due to the intake negative pressure flowing through the intake passage 25a. In any case, the blow-by gas blown from the combustion chamber 21 into the crank chamber 19 is returned from the communication passage 31a through the oil separator 32 to the intake passage 25a by the blow-by gas return pipe 31b, and is led to the combustion chamber 21 again. It is like that.

  The oil separator 32 according to this embodiment provided in the middle of the blow-by gas recovery passage 31 is defined in the cylinder head cover 15 by a partition member 37 disposed on the cylinder head cover 15 of the engine 10. As described above, by arranging the oil separator 32 in the cylinder head cover 15, blow-by gas can be prevented from flowing into the cam chamber 22. The oil separator 32 includes an inlet port 32 a formed in the partition member 37, an outlet port 32 b formed in the cylinder head cover 15, a filter 38 that captures oil contained in blow-by gas, and the cam chamber 22 of the engine 10. And an oil recovery port 32c communicating with the.

  The inlet port 32a is connected to the upstream side of the blowby gas recovery passage 31, that is, the previous communication passage 31a, and the outlet port 32b is connected to the downstream side of the blowby gas recovery passage 31, that is, the blowby gas return pipe 31b.

The filter 38 including the oil aggregation preventing member is arranged so as to partition the inlet port 32a and the outlet port 32b so as to cover the inlet port 32a. The filter 38 captures the mist-like engine oil contained in the blow-by gas and separates it. To an integral oil sump 37a. The oil aggregation preventing member in the present embodiment includes an ion exchange resin that adsorbs a conjugate base of a substance that reacts with moisture contained in blow-by gas and exhibits acidity. More specifically, in order to remove nitrate ions NO ₃ ⁻ that can be generated by NO _x and water in blow-by gas and sulfate ions SO ₄ ²⁻ that can be generated by SO _x and water in blow-by gas, An anionic ion exchange resin having a function of adsorbing ions. Such an anionic ion exchange resin has a function of releasing ions that do not suppress or promote deterioration of the engine oil 16, for example, hydroxide ions OH ⁻ , instead of adsorbing the NO ₃ ⁻ and SO ₄ ²⁻ described above. .

In addition, when using an anionic ion exchange resin as an oil aggregation inhibiting member, the following ions can be cited as ions desired to be adsorbed in addition to the nitrate ions and sulfate ions described above. That is, acetate ions CH ₃ COO ⁻ , formate ions HCOO ⁻ , chloride ions Cl ⁻ , chromate ions CrO ₄ ^{2− and the} like that can be generated from blow-by gas. Therefore, it is possible to use an anionic ion exchange resin having a function of adsorbing at least one of these ions.

  Such an ion exchange resin can adopt various shapes such as a granular or porous sheet, and the appearance of the filter 38 in this embodiment is schematically shown in FIG. That is, in this embodiment, a filter 38 is formed by a metal plate material having a large number of openings 39a, that is, a so-called punching metal case 39 and a granular ion exchange resin (not shown) filled in the case 39. ing. In this case, it is necessary to make the particle size of the ion exchange resin larger than the diameter of the opening 39a formed in the case 39, and the actual contour shape of the case 39 needs to correspond to the shape of the cylinder head cover 15. Needless to say. The case 39 can be formed by processing a wire mesh or the like. As shown in FIG. 3 schematically showing the appearance of the filter 38 according to another form, two ion exchange resins 40 having a porous sheet shape are used. It is also effective to form by laminating as described above. In this case, the case can be eliminated by providing the laminate itself of the ion exchange resin 40 with shape retention.

  It should be noted that the oil aggregation preventing member is not limited to the above-described anionic ion exchange resin. That is, it is possible to use an inorganic ion exchanger, a chelate resin and / or a synthetic adsorbent having a function of preventing the engine oil 16 from aggregating into sludge on the filter 38 as the oil aggregation preventing member. Therefore, the components to be removed from the blowby gas or the atmosphere around the filter 38 by the oil aggregation preventing member are not limited to the above-described nitrate ions and sulfate ions. For example, it may include components generated from additives contained in the engine oil 16 and unnecessary components or impurities such as metal powder generated by wear and / or elution of the components of the engine 10. As described above, when the oil aggregation preventing member that can remove unnecessary components and impurities in the engine oil 16 is used, such materials and chemicals that the engine oil 16 may contain such unnecessary components and impurities. Substances can be added as additives. More specifically, these can be added to the engine oil 16 as an antioxidant, a metallic detergent, a friction modifier, an ashless dispersant, and a pH adjuster.

  The oil recovery port 32 c is formed in an oil sump 37 a integral with the partition member 37, and guides oil captured by the filter 38 to the cam chamber 22. Accordingly, it is possible to prevent a problem that the engine oil 16 is mixed into the intake passage 25a through the blow-by gas return pipe 31b.

  Thus, since the filter 38 of the oil separator 32 including the oil aggregation preventing member is arranged so as to cover the inlet port 32a, the mist-like shape captured by the filter 38 at the inlet port 32a of the oil separator 32 is provided. There is no problem that the engine oil 16 aggregates. The captured engine oil 16 is transmitted to the filter 38 through the filter 38 and discharged to the cam chamber 22 to lubricate the valve mechanism 20, and is guided to the crank chamber 19 through the ventilation communication passage 36a. . As a result, the engine oil 16 does not stay in the oil separator 32, and the generation of sludge can be suppressed.

  The glow plug 33 as heating means in the present invention is for heating the blow-by gas flowing into the inlet port 32a of the oil separator 32 and preventing condensation of water vapor contained in the blow-by gas. Of course, it is also possible to employ other heating means instead of the glow plug 33 as in the present embodiment.

  The temperature sensor 34 as temperature detecting means in the present invention detects the temperature of the blowby gas flowing through the blowby gas recovery passage 31 and outputs it to the ECU 35.

The ECU 35 as control means in the present invention controls the operation of the glow plug 33, that is, on / off of energization to the glow plug 33, based on the temperature detected by the temperature sensor 34. Specifically, the ECU 35 switches energization on / off to the glow plug 33 so that the blow-by gas exceeds the dew point temperature. As a result, it is possible to suppress such a problem that water droplets are captured by the filter 38 and react with NO _x contained in the blow-by gas to generate nitric acid or the like. In other words, when the blow-by gas exceeds the dew point temperature, no condensation of water vapor occurs, so that the glow plug 33 is not energized, and wasteful power consumption can be avoided.

As described above, when the ECU 35 determines that the blow-by gas is equal to or lower than the dew point temperature based on the detection signal from the temperature sensor 34, the ECU 35 energizes the glow plug 33 to heat the blow-by gas and is included in the blow-by gas. Prevent water vapor condensation. As a result, water vapor can be returned to the intake system together with the blow-by gas passing through the oil separator 32, and adverse effects due to the moisture trapped by the filter 38 can be prevented. In particular, by using an anionic ion exchange resin that adsorbs a conjugate base of a substance that shows acidity by reacting with moisture contained in blow-by gas, the formation of nitric acid due to the reaction between NO _x contained in blow-by gas and water is prevented. Can be prevented. As a result, it is possible to reliably suppress a problem that the engine oil 16 is sludged by nitric acid.

  A ventilation passage 36 that guides clean air from the intake passage 25a upstream of the throttle valve 28 to the crank chamber 19 is defined by a ventilation communication passage 36a formed in the engine 10 and an air introduction pipe 36b. . The ventilation communication path 36a is connected to the cylinder head 14 and the cylinder block 13 so as to communicate with the crank chamber 19 via the chamber 42 defined by the partition member 41 in the cylinder head cover 15 and the cam chamber 22 above. It is formed straddling. One end side of the air introduction pipe 36 b connected to the intake pipe 25 and the chamber 42 communicates with the intake passage 25 a between the air filter 38 and the throttle valve 28, and the other end side is defined in the cylinder head cover 15. It is connected to the chamber 42. Accordingly, the ventilation passage 36 and the chamber 42 are in a positive pressure state substantially the same as the atmospheric pressure. The partition member 41 that defines the chamber 42 together with the cylinder head cover 15 is for preventing the engine oil 16 interposed in the cam chamber 22 from flowing into the air introduction pipe 36b. The opening 41a which connects is formed. Accordingly, clean air is guided from the air introduction pipe 36b to the chamber 42 and the cam chamber 22, and is further fed into the crank chamber 19 through the ventilation communication path 36a.

  In the above-described embodiment, the oil separator 32 is provided in the cylinder head cover 15 of the engine 10 and is integrated with the engine 10 to make the blow-by gas reduction device compact. However, the oil separator may be provided in contact with the cylinder block 13 or may be disposed in the middle of the blow-by gas return pipe 31b between the cam chamber 22 and the intake passage 25a. When the oil separator is provided in contact with the cylinder block 13, the temperature of the oil separator can be increased by heat radiation from the cylinder block 13, and condensation of moisture in the blow-by gas can be prevented. In addition, when an ion exchange resin is used as the oil aggregation preventing member of the filter 38, it is possible to sufficiently exhibit the ion exchange function by maintaining this in an active state. When the oil separator is arranged in the middle of the blow-by gas return pipe 31b between the cam chamber 22 and the intake passage 25a, the heating means and the temperature detection means are placed in the blow-by gas return pipe 31b upstream of the oil separator 32. It is preferable to arrange them.

  It should be noted that the present invention should be construed only from the matters described in the claims, and in the above-described embodiment, all the changes and modifications included in the concept of the present invention are other than those described. Is possible. That is, all matters in the above-described embodiment are not intended to limit the present invention, and include any configuration not directly related to the present invention. To get.

DESCRIPTION OF SYMBOLS 10 Engine 11 Oil pan 12 Crankcase 13 Cylinder block 13a Intake port 13b Exhaust port 14 Cylinder head 15 Cylinder head cover 16 Engine oil 17 Crankshaft 18 Piston 19 Crank chamber 20 Valve mechanism 20a Intake valve 20b Exhaust valve 20c Cam 21 Combustion chamber 22 Cam chamber 23 Fuel injection valve 24 Spark plug 25 Intake pipe 25a Intake passage 26 Air cleaner 27 Surge tank 28 Throttle valve 29 Connecting rod 30 Blow-by gas reduction device 31 Blow-by gas recovery passage 31a Communication passage 31b Blow-by gas return piping 32 Oil separator 32a Inlet port 32b Outlet port 32c Oil recovery port 33 Glow plug 34 Temperature sensor 35 ECU
36 Ventilation passage 36a Ventilation communication passage 36b Air introduction pipe 37 Partition member 37a Oil sump 38 Filter 39 Case 39a Opening 40 Ion exchange resin 41 Partition member 41a Opening 42 Chamber

Claims (4)

A blow-by gas recovery passage for guiding blow-by gas from the crank chamber of the internal combustion engine to the intake passage of the internal combustion engine;
Provided in the middle of this blow-by gas recovery passage, an inlet port connected to the upstream side of the blow-by gas recovery passage, an outlet port connected to the downstream side of the blow-by gas recovery passage, and the inlet port and the outlet port are partitioned A blow-by comprising an oil separator having a filter arranged so as to capture oil contained in blow-by gas and an oil recovery port for guiding the oil captured by the filter to the crank chamber side of the internal combustion engine A gas reduction device,
The blow-by gas reduction device according to claim 1, wherein the filter of the oil separator includes an oil aggregation preventing member and is disposed so as to cover the inlet port.   The blow-by gas reduction device according to claim 1, further comprising heating means for heating blow-by gas flowing into the inlet port of the oil separator.   The apparatus further comprises temperature detecting means for detecting the temperature of the blowby gas flowing through the blowby gas recovery passage, and control means for controlling the operation of the heating means based on the temperature detected by the temperature detecting means. The blowby gas reduction apparatus according to claim 2.   The said oil coagulation prevention member contains the ion exchange resin which adsorb | sucks the conjugate base of the substance which reacts with the water | moisture content contained in blow-by gas, and shows an acidity. Blow-by gas reduction device.

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