JP2017008808A - Blow-by gas recirculation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove frost and/or ice adhered onto an inner wall surface without consuming electric power in a blow-by gas recirculation device.SOLUTION: This blow-by gas recirculation device includes a blow-by gas pipe 55a, a coil spring 56 and a scraper 57. The blow-by gas pipe is connected to a surge tank 34 so as to recirculate blow-by gas leaked into a crank case of an internal combustion engine in an intake passage. One end of the coil spring is supported by the blow-by gas pipe so that the coil spring can be extended/contracted in a flowing direction of the blow-by gas in the blow-by gas pipe. The scraper is supported by the other end of the coil spring, and reciprocates inside the blow-by gas pipe when the vibration of the blow-by gas pipe causes the coil spring to be extended/contracted, so as to scrape off frost and/or ice adhered onto inner wall surfaces 35b, 55b of a passage having the blow-by gas flowing therein and located in a region in the vicinity of a connection portion between the blow-by gas pipe and the surge tank.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a blow-by gas recirculation device that causes a blow-by gas leaked into a crankcase of an internal combustion engine to flow and recirculate to the intake passage of the internal combustion engine.

  Conventionally, blow-by gas recirculation devices for recirculating blow-by gas leaking into a crankcase of an internal combustion engine to an intake system (intake passage) have become widespread. Blow-by gas contains a large amount of moisture in addition to unburned fuel (HC). Therefore, when the internal combustion engine is used in a low-temperature environment (for example, about −20 ° C. or less), the moisture is frozen in the blow-by gas pipe in the vicinity of the intake passage, and is formed as frost and / or ice on the inner wall surface of the blow-by gas pipe. It is known to adhere. If frost and / or ice continue to adhere to the inner wall surface of the blow-by gas pipe, the flow of the blow-by gas pipe is hindered and the blow-by gas pipe is blocked, and as a result, the blow-by gas may not be properly circulated.

  Therefore, one of the conventional blow-by gas recirculation devices (hereinafter referred to as “conventional device”) includes a copper plate having a thermistor in the middle of the blow-by gas pipe. The thermistor measures the temperature of the copper plate. The copper plate is provided with a through portion so that blow-by gas can flow. In the conventional apparatus, when the temperature of the copper plate (the temperature of the thermistor) falls below a specified temperature, a heating current for heating the copper plate is passed. Therefore, the conventional apparatus prevents the condensation or freezing downstream of the copper plate by heating the blow-by gas flowing through the blow-by gas pipe with the copper plate (see, for example, Patent Document 1).

Japanese National Patent Publication No. 11-508664

  However, the conventional apparatus consumes electric power because the copper plate is used as a heater. In particular, there is a problem that power consumption increases as the usage environment is lower.

  The present invention has been made to address the above problems. That is, one of the objects of the present invention is to provide an apparatus capable of removing frost and / or ice attached to the inner wall surface of a blow-by gas passage without consuming electric power.

  The blow-by gas recirculation device of the present invention (hereinafter referred to as “the device of the present invention”) includes a blow-by gas pipe, a spring member, and a scraper.

  The blow-by gas pipe is connected to a member constituting the intake passage so that the blow-by gas leaked into the crankcase of the internal combustion engine flows and is returned to the intake passage of the internal combustion engine.

  A part of the spring member is supported by the blow-by gas pipe so that the spring member can expand and contract in the flow direction of the blow-by gas inside the blow-by gas pipe.

  The scraper is supported by the other part of the spring member, and reciprocates inside the blow-by gas pipe when the spring member expands and contracts due to vibration of the blow-by gas pipe, so that the blow-by gas pipe and the scraper The frost and / or ice adhering to the inner wall surface of the passage through which the blow-by gas flows in the vicinity of the connection portion with the member constituting the intake passage is scraped off.

  A blow-by gas pipe (for example, PCV (Positive Crankcase Ventilation) hose) vibrates due to vibration generated during operation of the internal combustion engine or vibration during travel of a vehicle equipped with the engine. Further, as the blow-by gas pipe is vibrated, the spring member partially supported by the blow-by gas pipe expands and contracts inside the blow-by gas pipe. As a result, the scraper supported by the other part of the spring member moves (reciprocates) in the blow-by gas pipe.

  At this time, the scraper scrapes off the frost and / or ice. Therefore, according to the apparatus of the present invention, it is possible to remove frost and / or ice generated on the inner wall surface of the passage through which blow-by gas flows without using a heating device (that is, without consuming electric power). .

FIG. 1 is a schematic view of a blow-by gas recirculation apparatus according to an embodiment of the present invention and an internal combustion engine to which the blow-by gas recirculation apparatus is applied. FIG. 2 is a partial cross-sectional view of the blow-by gas pipe and the surge tank shown in FIG. FIG. 3 is a partial cross-sectional view of a blow-by gas pipe and a surge tank of a blow-by gas recirculation apparatus according to a modification of the embodiment. FIG. 4 is a partial cross-sectional view of a blow-by gas pipe and a surge tank of a blow-by gas recirculation device according to another modification of the embodiment. FIG. 5 is a partial cross-sectional view of a blow-by gas pipe and a surge tank of a conventional blow-by gas recirculation device.

  Hereinafter, a blowby gas recirculation apparatus (hereinafter referred to as “the present recirculation apparatus”) according to an embodiment of the present invention will be described with reference to the drawings.

(Constitution)
The present reflux device is applied to the internal combustion engine 10 shown in FIG. The engine 10 is a spark ignition type four-cycle piston reciprocating type, in-line four-cylinder, gasoline internal combustion engine. The engine 10 includes an engine body 20, an intake system 30, and an exhaust system 40.

  The engine body 20 includes a crankcase 21, a crankshaft 22, a cylinder block 23, a piston 23c, a connecting rod 23e, a cylinder head 24, an intake valve 25, an exhaust valve 26, a fuel injection valve 27, and an ignition device 28.

  The crankcase 21 supports the crankshaft 22 to be rotatable. Hereinafter, the crankcase 21 and the oil pan OP constitute a crankcase chamber 21a.

  The cylinder block 23 is fixed to the crankcase 21 above the crankcase 21. The cylinder block 23 is made of aluminum and includes a plurality of hollow cylinders (cylinder bores) 23a (for four cylinders, that is, four). A cast iron cylinder liner 23b is fitted into the inner periphery of the cylinder 23a.

  A piston 23c is accommodated in the cylinder 23a. The piston 23c is substantially cylindrical and includes a plurality of piston rings 23d on the side surface. The piston 23c is connected to the crankshaft 22 by a connecting rod 23e. The upper surface (top surface) of the piston 23 c forms a combustion chamber CC together with the inner wall surface of the cylinder liner 23 b and the lower surface of the cylinder head 24.

  The cylinder head 24 is fixed to the cylinder block 23 above the cylinder block 23. The cylinder head 24 is formed with an intake port IP that communicates with the combustion chamber CC and an exhaust port EP that communicates with the combustion chamber CC. The intake port IP is opened and closed by an intake valve 25. The exhaust port EP is opened and closed by an exhaust valve 26. The cylinder head 24 is covered with a cylinder head cover 24c. A fuel injection valve 27 and an ignition device 28 are provided in the cylinder head 24.

  When the intake valve 25 is opened during the intake stroke of the engine 10, a mixture of fuel and intake air injected from the fuel injection valve 27 is introduced into the combustion chamber CC from the intake port IP. Thereafter, when the air-fuel mixture is ignited by the ignition device 28 in the compression stroke and the air-fuel mixture explodes, if there is a gap between the piston ring 23d and the cylinder liner 23b, the combustion gas containing unburned fuel is cranked from the gap. It leaks into the case chamber 21a. This leaked gas is called “blow-by gas”. Blow-by gas contains a large amount of moisture in addition to unburned fuel.

  The intake system 30 includes an intake pipe 31, an air filter 32, a throttle valve 33, and a surge tank 34.

  The intake pipe 31 is connected to the intake port IP. Accordingly, the intake pipe 31, the surge tank 34, and the intake port IP constitute an intake passage. The intake pipe 31 is a “member constituting the intake passage”. The throttle valve 33 is provided to adjust the amount of intake air supplied to the engine 10. The intake air flows in the direction of arrow A1 in FIG.

  The surge tank 34 is provided in the middle of the intake pipe 31. The surge tank 34 is a “member constituting the intake passage”. When the opening of the throttle valve 33 is relatively low (for example, when the vehicle is decelerated and idling), the pressure in the surge tank 34 is lower than the pressure in the intake pipe 31 upstream of the throttle valve 33. Such a state is referred to as an “intake negative pressure” state.

  The exhaust system 40 includes an exhaust pipe 41 and a catalyst device 42. The exhaust pipe 41 is connected to the exhaust port EP. Therefore, the exhaust pipe 41 and the exhaust port EP constitute an exhaust passage.

  The blow-by gas recirculation device 50 includes a first gas passage portion 51, a second gas passage portion 52, a third gas passage portion 53, a PCV valve 54, a fourth gas passage portion 55, a coil spring (spring member) 56, and a scraper 57. .

  The first gas passage portion 51 is configured by a gas pipe 51 a provided outside the main body of the engine 10. One end of the first gas passage 51 is connected to the cylinder head cover 24c. The other end of the first gas passage 51 is connected to the intake pipe 31 on the intake upstream side of the throttle valve 33.

  The second gas passage portion 52 is formed in the cylinder head 24. Therefore, the second gas passage portion 52 communicates with the intake upstream side of the intake pipe 31 through the first gas passage portion 51 with respect to the throttle valve 33. Further, the second gas passage 52 is connected to the PCV valve 54 through a predetermined path in the cylinder head 24.

  The third gas passage portion 53 is formed in the cylinder block 23. The third gas passage 53 communicates the second gas passage 52 in the cylinder head 24 with the crankcase chamber 21a.

  The PCV valve 54 is a check valve type valve and is attached to the opening of the cylinder head 24. The PCV valve 54 opens when the pressure in the cylinder head 24 (crankcase chamber 21a) is higher than the pressure in the surge tank 34. When the difference between the pressure in the cylinder head 24 and the pressure in the surge tank 34 is excessively large, the PCV valve 54 can reduce its opening and limit the amount of blow-by gas that passes through the PCV valve 54. It is like that.

  The fourth gas passage portion 55 is configured by a blow-by gas pipe 55a provided outside the main body of the engine 10. The blow-by gas pipe 55a is also referred to as a “PCV hose”. One end of the fourth gas passage portion 55 is connected to the discharge portion of the PCV valve 54, and the other end is connected to the surge tank 34 on the intake downstream side of the throttle valve 33. One end of a coil spring 56 having a scraper 57 is supported on the inner wall surface of the blow-by gas pipe (PCV hose) 55a in the vicinity of the connection portion CN with the surge tank 34. Hereinafter, the coil spring 56 provided with the scraper 57 is also referred to as a “frost scraper”.

  The first gas passage 51 and / or the fourth gas passage 55 may be provided with an oil catch tank that separates and removes oil mist and soot contained in the blow-by gas.

  In the above configuration, when intake negative pressure (hereinafter also simply referred to as “negative pressure”) is generated in the surge tank 34, the pressure in the cylinder head 24 is higher than the pressure in the surge tank 34. It is high. Therefore, in this case, the PCV valve 54 is opened. At this time, the blow-by gas leaked from the combustion chamber CC into the crankcase chamber 21a is in accordance with the direction of arrow A2 in FIG. 1, the second gas passage portion 52, the third gas passage portion 53, the PCV valve 54, and the fourth gas passage portion 55. Then, it is returned (inflowed) to the surge tank 34 (intake system 30). At the same time, the intake air flows into the crankcase chamber 21a through the first gas passage portion 51, the second gas passage portion 52, and the third gas passage portion 53 as shown by an arrow A3 in FIG.

  Next, the structure of the “frost scraping portion” of the fourth gas passage portion 55 will be described with reference to FIG. FIG. 2 shows a cross-sectional view of the connection portion CN between the blow-by gas pipe 55a constituting the fourth gas passage portion 55 and the surge tank 34 and the vicinity thereof.

  The blow-by gas pipe 55 a is connected to the surge tank 34 via a cylindrical connection pipe member (so-called “union”) 35 fitted into the wall of the surge tank 34. Specifically, the connecting pipe 35 is inserted into the blow-by gas pipe 55a such that the inner wall surface 55b of the blow-by gas pipe 55a contacts the outer wall surface 35a of the connecting pipe 35. An annular protrusion 55c is provided on a part of the inner wall surface 55b of the blow-by gas pipe 55a along the inner periphery of the blow-by gas pipe 55a.

  One end of the coil spring 56 is supported by the protrusion 55c (blow-by gas pipe 55a) so that the coil spring 56 can expand and contract along the flow direction of the blow-by gas inside the blow-by gas pipe 55a. That is, the coil spring 56 is supported so that the axial direction C of the coil spring 56 and the flow direction of blow-by gas are parallel. The outer diameter of the coil spring 56 is substantially equal to the inner diameter of the protrusion 55c.

  A scraper 57 is fixed to the other end of the coil spring 56 (that is, the end not fixed to the protrusion 55c). The scraper 57 has a substantially disk shape. The scraper 57 is made of resin. The outer diameter of the scraper 57 is smaller than the inner diameter of the connecting pipe 35. The thickness of the outer peripheral portion 57a of the scraper 57 decreases from the center of the scraper 57 in the radially outward direction, and the outer peripheral portion 57a of the scraper 57 has a “blade shape” with a sharp outermost portion. Yes. A through hole 57b is provided at the center of the scraper 57 so as not to hinder the flow of blow-by gas. As will be described in detail later, the scraper 57 reciprocates inside the blow-by gas pipe 55a when the coil spring 56 expands and contracts due to vibration of the blow-by gas pipe 55a.

  In FIG. 2, the flow direction of blow-by gas is the direction from the top to the bottom of the page, as indicated by arrow A2.

(Frost and / or ice adhesion)
Before describing the operation of the “frost scraping portion” in the fourth gas passage portion 55 configured as described above, referring to FIG. 1 and FIG. 5 (in the case where there is no “frost scraping portion”), A state where frost and / or ice adhere to the gas passage portion 55 and the connecting pipe 35 will be described.

  When the pressure in the surge tank 34 is lower than the pressure in the crankcase chamber 21a, the PCV valve 54 shown in FIG. 1 is opened. The blow-by gas containing unburned components and moisture that has passed through the PCV valve 54 passes through the fourth gas passage portion 55, and in the connection portion CN (connection pipe 35) between the fourth gas passage portion 55 and the surge tank 34. It merges with the intake air flowing through the tank 34.

  The temperature of the intake gas in the surge tank 34 is equivalent to the outside temperature of the vehicle on which the engine 10 is mounted. Therefore, the relatively hot blow-by gas discharged from the crankcase chamber 21a is cooled by the intake gas at the connection portion CN. In particular, when the blow-by gas is cooled by low-temperature intake air at a low temperature (for example, about −20 ° C. or less), the water (water vapor) contained in the blow-by gas is rapidly cooled and frozen to become frost and / or ice. . Hereinafter, “frost and / or ice” is also simply referred to as “frost”. As shown in FIG. 5, the frost FR adheres to the inner wall surface 55 b of the fourth gas passage portion 55 and the inner wall surface 35 b of the connecting pipe member 35.

(Function)
Next, the operation of “frost scraping” of the “frost scraper” will be described with reference to FIG.

  During operation, the engine 10 is mechanically vibrated by the rotational movement of the crankshaft 21a and the reciprocating movement of the piston 23d. Therefore, the fourth gas passage 55 connected to the engine 10 (the cylinder head 24) also vibrates together with the engine 10. For example, when the rotational speed NE of the engine 10 changes between 700 and 6000 rpm, the natural vibration frequency of the mechanical vibration changes between 11.7 and 100 Hz.

  One end of the coil spring 56 is fixed to the protruding portion 55 c of the fourth gas passage portion 55. Therefore, when the engine 10 vibrates, one end of the coil spring 56 is displaced in accordance with the vibration displacement of the engine 10 (displacement of the fourth gas passage portion 55). The other end (the side on which the scraper 57 is fixed) of the coil spring 56 is subjected to the same displacement as that of the one end of the coil spring 56, and the degree of expansion and contraction of the force by the product of the weight and acceleration of the coil spring 56 and scraper 57 The force according to Since the scraper 57 is constrained by the coil spring 56, the scraper 57 is displaced relative to the fourth gas passage portion 55 in the flow direction of blow-by gas by the “force to be restored” of the coil spring 56 (single vibration). To do.

  As described above, the scraper 57 reciprocates in the fourth gas passage portion 55 due to the vibration of the engine 10 and the like, and when the vibration frequency of the engine 10 and the vibration frequency of the “frost scraper” coincide, Displaces greatly. At this time, as shown in FIG. 3, the scraper 57 reciprocates while scraping the frost FR adhering to the inner wall surface 55b of the fourth gas passage portion 55 or the inner wall surface 35b of the connecting pipe 35 by the blade portion 57a. Therefore, this recirculation | reflux apparatus can prevent the inside of the 4th gas passage part 55 and the connection pipe material 35 being obstruct | occluded by the frost FR.

  The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention.

(Modification)
The shape of the coil spring may be conical as shown in FIG. In this case, it is not necessary to provide the protrusion 55c, or the height of the protrusion 55c (the length of the protrusion in the radial direction of the fourth gas passage 55) can be reduced. Therefore, in this case, elements that hinder the flow of blow-by gas can be reduced.

  It should be noted that the engine to which the present reflux device is applied may be another type of engine (for example, a diesel engine).

  The scraper 57 described is made of resin, but the scraper may be metal and hard rubber. The shape of the scraper is not limited to the shape shown in FIG. 2, and may be a shape capable of scraping off frost attached to the inner wall surface 55 b of the fourth gas passage portion 55, for example, a simple disk shape. Furthermore, the scraper may be provided with brush hairs on its outer periphery.

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine (engine), 21 ... Crankcase, 30 ... Intake system, 31 ... Intake pipe, 33 ... Throttle valve, 34 ... Surge tank, 35 ... Connecting pipe, 35b ... Connecting pipe inner wall surface, 54 ... PCV Valve, 55 ... 4th gas passage part, 55a ... Blow-by gas pipe, 55b ... Inner wall surface of blow-by gas pipe, 55c ... Projection part, 56 ... Coil spring, 57 ... Scraper.

Claims (1)

In a blow-by gas recirculation device comprising a blow-by gas pipe connected to a member constituting the intake passage so that the blow-by gas leaked into the crankcase of the internal combustion engine flows and recirculates to the intake passage of the internal combustion engine.
A spring member partially supported by the blow-by gas pipe so as to be able to expand and contract along the flow direction of the blow-by gas inside the blow-by gas pipe;
The blow-by gas pipe and the intake passage are configured by reciprocating in the blow-by gas pipe when the spring member is supported by the other part of the spring member and the spring member expands and contracts due to vibration of the blow-by gas pipe. A scraper that scrapes off frost and / or ice adhering to the inner wall surface of the passage through which the blow-by gas flows in a region in the vicinity of the connection portion with the member to be
A blow-by gas recirculation apparatus comprising:

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