JP2009209813A - Blow-by gas recirculation device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent blow-by gas recirculating performance from being deteriorated due to the freezing of a PCV valve by the moisture contained in the blow-by gas in a gas passage. <P>SOLUTION: The blow-by gas flowing through the PCV valve 14 is released into a chamber 300 formed in an oil separation cover 10, and advances through a third gas passage 15 after passing through an opening 15a formed in the chamber 300. The opening 15a is formed in the chamber at a vertical lower position than the downstream side end of the PCV valve when the chamber is mounted on a vehicle and at a vertical lower intermediate position of the chamber when the chamber is mounted on the vehicle. Therefore, the casing of the PCV valve 14 can be used as a weir, and condensed moisture is allowed to remain in the chamber. Also, even in an extremely low temperature state, the downstream side end of the PCV valve, the interior of the PCV valve, and the opening 15a in the chamber are prevented from being closed due to the freezing of the moisture. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a blow-by gas recirculation device for an engine, and in particular, has an intake system having a throttle valve and an intake passage, and a PCV valve installed downstream of an oil separation space for blow-by gas. The present invention relates to an apparatus for separating oil from blow-by gas introduced into the oil separation space from the inside and supplying the oil to the intake system.

  With the internal combustion of the engine, a so-called blow-by gas containing unburned components leaking from the combustion chamber is generated in the crank chamber inside the cylinder block and the oil pan. The blow-by gas is collected, recirculated to the intake system, and burned again. However, since the collected blow-by gas contains oil mist from lubricating oil and the like, oil components are not separated. If it is sufficient, the exhaust system catalyst may be adversely affected.

  In view of the above, an oil separator chamber for separating oil from blow-by gas is provided in the engine body, and a positive crankcase Ventilation valve (hereinafter referred to as a PCV valve) is connected to the oil separator chamber, and a PCV hose and an intake system are connected to a PCV hose. In general, a device for connecting blow-by gas from which oil is separated to the intake system is known. In such an apparatus, the PCV valve, the PCV hose, and the like are cooled by running air at an extremely low temperature and the moisture contained in the blow-by gas is frozen, which may adversely affect the reflux performance.

  As a countermeasure against such a problem, for example, a structure disclosed in JP-A-2002-106429 is known. That is, in this publication, the engine is placed horizontally so that the resin intake manifold faces the vehicle front side with respect to the vehicle front-rear direction, and the recess on one side of the engine is covered with a cover made of synthetic resin. And the PCV valve and the PCV hose are within the projection plane of the intake manifold when viewed from the front side of the vehicle.

  Also known is a technique in which a PCV valve is arranged in an oil separator chamber in order to prevent freezing while improving the compactness around the intake air. (For example, Patent Document 2 below)

JP 2002-106429 A JP-A-2-176110

  In the device of Patent Document 1, the PCV valve and the PCV hose are accommodated in the projection surface of the intake manifold located on the front side of the vehicle. Prevents freezing of moisture in blow-by gas.

  Even in such a device, moisture contained in the blow-by gas exists in the gas passage, and when the intake negative pressure decreases, the moisture may flow back through the PCV hose and reach the PCV valve. is there. In particular, when the engine is started in the early morning of winter, the elapsed time from the engine stop is long, and the tendency becomes remarkable. At extremely low temperatures, if the water freezes in a state where water has accumulated in the opening of the PCV valve or inside the PCV valve, malfunction of the PCV valve occurs, which may lead to deterioration of the reflux performance.

  Even when the PCV valve is arranged in the oil separator chamber to prevent freezing as in Patent Document 2, it is possible to prevent freezing with the heat generated while the engine is operating, but once the engine is stopped. If the period after restarting is long, the opening of the PCV valve may be already frozen. In this case, the blow-by gas recirculation control becomes difficult until the freezing is eliminated and the PCV valve becomes operable.

  An object of the present invention is to prevent the PCV valve from freezing due to moisture contained in the blow-by gas in the gas passage.

  The blow-by gas recirculation device for an engine according to claim 1 includes a gas passage that connects the crank chamber of the engine and an intake system for supplying intake air via an oil separation space, and oil-separates blow-by gas generated from the inside of the engine. A PCV valve provided in a gas passage portion downstream of the oil separation space, the downstream end portion of which is positioned above the upstream end portion in the vertical direction. A PCV valve, and a chamber formed vertically above and around the downstream portion of the PCV valve, and an upstream end of a gas passage portion connected downstream to the chamber and connected to the intake system is the PCV. It is characterized in that it communicates with the chamber at a position vertically below the downstream end of the valve.

  According to the first aspect of the present invention, even if the water present in the gas passage flows backward, the PCV valve is not affected using the chamber.

  An engine blow-by gas recirculation device according to claim 2 is characterized in that, in the invention of claim 1, the upstream end of the gas passage connected to the intake system is connected to the chamber at an intermediate position in the vertical direction of the chamber. Yes.

  According to the invention of claim 2, it is possible to secure the amount of water accumulated in the chamber.

  According to a third aspect of the present invention, the oil separation space is defined by a recess on one side of the engine body and an oil separation cover that covers the recess, and the PCV valve is upstream of the valve. The chamber is mounted on the oil separation cover with the side protruding into the oil separation space, and the chamber is formed between the oil separation cover and the PCV valve.

  According to the invention of claim 3, the PCV valve can be disposed in the recess on the one side of the engine body, and the chamber can be easily formed using the oil separation cover.

  According to the first aspect of the present invention, it is possible to prevent the moisture of the blow-by gas flowing backward from the gas passage from being accumulated in the opening of the PCV valve or inside the PCV valve by using the chamber.

  According to the second aspect of the present invention, it is possible to secure the volume of moisture accumulated in the chamber and to prevent the gas passage from being blocked due to moisture freezing.

  According to the invention of claim 3, since the PCV valve can be disposed in the recess on one side of the engine body, it is possible to further prevent the deterioration of the blow-by gas recirculation performance due to moisture freezing. Furthermore, the chamber can be formed using an oil separation cover.

  Hereinafter, the best mode for carrying out the present invention will be described based on examples.

First, an outline of an engine according to the present invention will be described with reference to FIG.
The engine body ENG is composed of a cylinder head 1, an upper block 2, a lower block 3, and an oil pan 4 constituting a cylinder block, and a plurality of cylinders, specifically, four cylinders are arranged in the vehicle width direction. This is a so-called 4-cylinder horizontal engine laid out in the engine room.

  The upper block 2 and the lower block 3 are fastened and fixed in a state where a crankshaft (not shown) is rotatably supported, and is placed on the oil pan 4. In order to prevent vibration of the engine ENG, the front side of the lower block 3 is connected to the bulkhead 5 as a vertical wall that cuts off between the cylinders on the side of the upper block 2 and the bearing of the crankshaft is formed on the side of the lower block 3. The configuration is a lattice structure.

  An intake unit IU that supplies air to a combustion chamber (not shown) of the engine is formed by a throttle body 6, a surge tank 7 that constitutes an intake passage, a branch intake passage 8, and the like.

Air sucked from the air cleaner is guided to an intake duct (not shown) upstream of the throttle body 6 and supplied to a surge tank 7 forming a volume chamber. The throttle body 6 is a so-called electronically controlled throttle whose outer periphery is formed of a metal casing, the control unit of the engine calculates the control amount based on the operation amount of the accelerator pedal, and the throttle valve is controlled by an internal motor.
The air supplied to the surge tank 7 is connected to the cylinder head 1 by the branch intake passage 8 and supplied to the combustion chamber of each cylinder. The branch intake passage 8 is formed of a synthetic resin such as polyamide, and has a shape curved upward from the lower side of one side surface of the engine body in the forward direction of the vehicle. The intake unit IU is supported on the engine ENG by connecting to the cylinder head 1 described above, fastening to the upper block 2 via the stay 9, and cooperating with one side of the upper block 2 described later. This is performed by attaching to the oil separation cover 10 that forms the separation space OS.

  Next, the blow-by gas recirculation device will be described with reference to FIGS.

Here, FIG. 2 is a side view of the upper block 2 as viewed from the intake unit side.
FIG. 3 is a bottom view of the upper block 2,
4 is a diagram showing a cross section taken along line IV-IV in FIG.
FIG. 5 is a diagram showing a cross section taken along line VV in FIG.
6 is a cross-sectional view taken along line VI-VI in FIG.

  As shown in FIG. 2, an oil separation portion that forms an oil separation space OS in cooperation with the oil separation cover 10 along with a number of reinforcing ribs on the surface of the intake unit IU of the upper block 2 that is one side of the engine body. 200 is formed. The oil separation unit 200 is located in a concave portion corresponding to the cylinder bore of the intake unit IU side upper block 2. The cylinder arrangement is the first cylinder, the second cylinder, the third cylinder, and the fourth cylinder in order from the left side of the drawing.

  The oil separation part 200 has a cover attachment part 201 to which the attachment flange part 101 of the oil separation cover 10 is fastened, and six attachment bolt holes 202a to which the attachment flange part 101 of the oil separation cover 10 is fastened and fixed by bolts or the like. , 202b, 202c, 202d, 202e, 202f are provided at three locations on the left and right. The first, second, and third baffle plates 203, 204, and 205 that attach and separate oil contained in blow-by gas are disposed on the inner portion of the cover mounting portion 201. It is integrally formed from the unit IU side surface toward the front.

  The first baffle plate 203 located at the lowermost position is formed at a substantially intermediate portion in the vertical direction of the upper block 2 continuously from the left cover attaching portion 201 to the vicinity of the right cover attaching portion 201. Further, the front end portion in the direction of the intake unit IU extends to a position exceeding the intermediate portion of the oil separation space OS.

  The second baffle plate 204 located at the intermediate portion is formed at a substantially middle portion between the first baffle plate 203 and the upper end portion of the upper block 2 continuously from the right cover attaching portion 201 to a substantially middle portion of the oil separation space OS. Has been. The length of the second baffle plate 204 in the direction of the intake unit IU is about ¼ of that of the first baffle plate 203. Since the lower part of the upper block 2 forms the upper part of the crank chamber and the position corresponding to the cylinder bore is a recess, the tip part of the second baffle plate 204 is a position corresponding to the root part of the first baffle plate 203.

  The third baffle plate 205 located at the uppermost position is located approximately in the middle between the second baffle plate 204 and the upper end of the upper block 2, and is approximately in the middle of the second baffle plate 204 from the right cover mounting portion 201 in the longitudinal direction of the engine. The length in the direction of the intake unit IU is less than half of the second baffle plate 204.

  Inside the upper block 2, the first gas passage 11 and the second gas passage 12 are located in a portion of the bulkhead 5 between the third cylinder and the fourth cylinder with the crankshaft bearing portion and the bulkhead 5 sandwiched therebetween. It is formed so as to penetrate the crank chamber CR and the oil separation space OS. The order of the ignition timing of the engine in the present invention is the order of the first cylinder → the third cylinder → the fourth cylinder → the second cylinder, and the phase difference of the combustion stroke between the third cylinder and the fourth cylinder is 180. °.

  As shown in FIG. 3, first and second cutout portions 11a and 12a are provided at the lower end portions of the first gas passage 11 and the second gas passage 12, and cranks are provided via the cutout portions 11a and 12a. The blow-by gas of the chamber CR is introduced into the gas passages 11 and 12.

  Upper end openings 11 b and 12 b of the first and second gas passages 11 and 12 are opened at the base portion of the first baffle plate 203 and are provided upward so as to face the lower surface of the first baffle plate 203.

  The bottom surface portion of the oil separation space OS is formed so as to be positioned gradually downward in the vertical direction along the longitudinal direction of the engine, and the opening 13b below the upper end openings 11b, 12b of the first and second gas passages 11, 12. An oil return passage 13 is provided on the engine longitudinal direction side of the first and second gas passages 11 and 12.

  4 to 6, the oil separation cover 10 forms an oil separation space OS by covering the oil separation portion 200 provided on the intake unit IU side surface of the upper block 2 described above. The oil separation cover 10 is provided with a first rib 102 that extends toward the tip of the first baffle plate 203 and a second rib 103 that extends to the vicinity of the root of the first baffle plate 203. Yes.

  A PCV valve 14 is provided in the oil separation cover 10 with the upstream side protruding into the oil separation space OS, and the blow-by gas introduction opening 14a and the upper end openings 11b of the first and second gas passages 11 and 12, The first baffle plate 203 and the second rib 103 are interposed between the two b. The PCV valve 14 has a general structure in which a spring is installed in a cylindrical casing, and a valve body that opens against the urging force of the spring is attached to the tip of the PCV valve 14.

  In addition, a chamber 300 is formed integrally with the oil separation cover 10 in the vertical direction on the downstream side of the PCV valve 14 and in the vicinity thereof. The chamber 300 and the surge tank 7 communicate with each other through the third gas passage 15, and the opening 15 a of the third gas passage 15 to the chamber 300 is vertically lower than the downstream end portion of the PCV valve 14 and It is installed at an intermediate position vertically below. The third gas passage 15 is composed of an upstream portion 15 b formed in the oil separation cover 10 and a downstream portion 15 c formed in the surge tank 7. The upstream portion 15b corresponds to a gas passage portion that is downstream of the chamber 300 and connected to the intake unit IU.

  Based on FIG.7 and FIG.8, the connection form of the oil separation cover 10 and the surge tank 7 is demonstrated.

FIG. 7 is a perspective view in which an oil separation cover 10 is mounted on the intake unit side of the upper block 2;
FIG. 8 is a view showing a cross-section of the main part in which the oil separation cover 10 and the surge tank 7 are connected in communication.

  The oil separation cover 10 has a mounting flange portion 101 on its outer peripheral edge, and has five openings 104a, 104b, 104c, 104d, and 104f provided on the mounting flange portion 101 and mounting bolt holes 202a on the upper block side. , 202b, 202c, 202d, 202f are fastened with bolts or the like.

  On the right mounting flange portion 101, a surge tank mounting portion 400 having a cross-sectional cam-like column having substantially the same height as the oil separation space OS is formed integrally with the oil separation cover 10. The upper surface of the surge tank mounting portion 400 is a flat mounting seat surface 401 and is configured to come into contact with the mounting seat surface 7a of the surge tank 7 in a surface contact state.

  The mounting seat surface 401 of the surge tank mounting portion 400 is provided with a support opening 402 for fastening and supporting the surge tank 7 to the oil separation cover 10 with a bolt or the like. Further, the support opening 402 is positioned coaxially with the central mounting bolt hole 202e among the three mounting bolt holes provided on the right side of the cover mounting portion 201 of the upper block 2, and the surge tank 7 and the upper block The side mounting bolt holes 202e are configured to be fastened together with bolts or the like via the oil separation cover 10.

  A first opening 403 that forms a gas passage from the chamber 300 is formed in the vicinity of the support opening 402 of the mounting seat surface 401. The second opening 7b, which is the upstream end of the downstream portion 15c of the third gas passage 15 formed on the mounting seat surface 7a of the surge tank, and the first opening 403 are in contact with each other, so that the blow-by gas is surged. A third gas passage 15 to be supplied to the tank 7 is formed to penetrate therethrough.

  Next, the structure of the oil separation cover 10 according to the present invention will be described with reference to FIGS.

Here, FIG. 9 is a front view of the oil separation cover 10,
FIG. 10 is a side view of the oil separation cover 10;
11 is a diagram showing a cross section taken along line XI-XI in FIG.
12 is a diagram showing a cross section taken along line XII-XII of FIG.
13 is a diagram showing a cross section taken along line XIII-XIII of FIG.

  As shown in FIG. 9, the oil separating cover 10 includes a bulging portion 500, a mounting flange portion 101, a surge tank mounting portion 400, and a chamber 300 that are integrally formed of synthetic resin.

  The bulging portion 500 bulges toward the intake unit IU in a range extending over the upper portion of the oil separation cover 10 and the right side portion where the chamber 300 is installed, and cooperates with the oil separation portion 200 to form the oil separation space OS. Constitute. A second rib 103 is extended below the bulging portion 500 and at an intermediate portion of the oil separation cover 10, and a first rib 102 is installed below the second rib 103.

  The mounting flange portion 101 is provided on the outer peripheral edge portion of the oil separation cover 10 and has five openings 104a and 104b used for fastening at positions corresponding to the mounting bolt holes 201a, 201b, 202c, 202d, and 202f provided in the upper block. , 104 c, 104 d, 104 f are provided at substantially the middle positions of the upper and lower left and right corners and the left mounting flange 101.

  The surge tank mounting portion 400 is a columnar cam-shaped column, and is formed to extend from the right mounting flange portion 101 along the bulging portion 500 in the direction of the intake unit IU. A mounting seat surface 401 that forms a flat portion toward the intake unit IU is formed on the upper end surface of the surge tank mounting portion 400. The mounting seat surface 401 has a support opening 402 that is coaxial with the mounting bolt hole 202 e provided in the upper block 2.

  A first opening 403 is formed at a substantially intermediate portion between the support opening 402 and the upper right opening 104f so as to be in contact with the second opening 7a at a position facing the second opening 7a of the surge tank. Has been. The first opening 403 forms an upstream portion 15 b of the third gas passage 15 that supplies blow-by gas from the chamber 300.

  A PCV valve 14 is mounted inside the wall of the bulging portion 500 in the vicinity of the opening 104f on the upper right side, and a chamber 300 is formed around the downstream side thereof. As shown in FIGS. 10 and 11, the PCV valve 14 is disposed so that the introduction opening 14 a faces the second rib 103, so that blow-by gas supplied from the crank chamber CR is not directly introduced into the PCV valve 14. Is arranged.

  As shown in FIG. 13, the valve support member 16 is fastened and fixed from the back surface of the oil separation cover 10 so that the downstream portion of the PCV valve 14 is accommodated in the chamber 300.

  As shown in FIG. 12, the upstream portion 15 b of the third gas passage on the oil separation cover 10 side uses the inside of the wall of the oil separation cover 10 from the chamber 300 to the first opening 403 provided in the mounting seat surface 401. Communicate. In addition, the upstream opening 15a to the chamber 300 of the upstream portion 15b of the third gas passage is installed vertically below the end of the PCV valve 14 in the vehicle-mounted state and at an intermediate position vertically below the chamber 300. ing.

  Next, the operation and effect of the blow-by gas recirculation apparatus will be described.

  In the idling state or low load state, a negative pressure is generated downstream of the throttle valve, and the PCV valve 14 is opened against the urging force of the spring so that the crank chamber CR and the throttle valve downstream, specifically, Is connected to the surge tank 7 and blow-by gas in the crank chamber CR is sucked in by the negative intake pressure.

The blow-by gas is supplied from the first notch 11a of the crank chamber of the third cylinder and the second notch 12a of the crank chamber of the fourth cylinder formed on the crank chamber side wall surface of the mating surface portion of the upper block 2 and the lower block 3. It moves to the oil separation space OS through the first and second gas passages 11 and 12.
If a lattice structure using a bulkhead on the upper block side and a crankshaft bearing on the lower block side is used for the purpose of reducing vibration, the communication area of the crank chamber of each cylinder is small. Since the pressure fluctuation in the crank chamber of each cylinder becomes particularly significant, the crank chamber of the third cylinder and the crank chamber of the fourth cylinder have a phase difference of 180 ° across the same bulkhead so that the interval is the shortest distance. Is communicated. As a result, it is possible to further suppress the pressure fluctuation transmitted to the oil separation space OS.

The blow-by gas introduced into the oil separation space OS from the upper end openings 11b and 12b of the first and second gas passages collides with the root portion of the first baffle plate 203 disposed opposite to the upper end openings 11b and 12b. The oil mist contained in the gas advances toward the PCV valve while adhering to the baffle plate. The first, second and third baffle plates 203, 204 and 205 and the first and second ribs 102 and 103 are alternately arranged between the upper end openings 11b and 12b and the PCV valve introduction opening 14a. It has a maze structure.
With the above configuration, a sufficient path from the upper end openings 11b and 12b to the blow-by gas introduction opening 14a of the PCV valve can be secured, and the pressure fluctuation affecting the opening 14a can be minimized and the blow-by gas can be prevented. Oil separation performance is improved.

  On the other hand, the oil adhering to the baffle plate and the ribs flows down to the oil separation portion bottom surface 200 along the upper block wall surface and the oil separation cover inner wall surface, and enters the inside of the crank chamber CR from the oil return passage opening 13b formed at the lowest portion. Refluxed.

  The blow-by gas that has passed through the PCV valve 14 is discharged into a chamber 300 formed in the oil separation cover 10, passes through an opening 15 a provided in the chamber 300, and is downstream from the upstream portion 15 b of the third gas passage. It progresses with the part 15c.

  The installation position of the opening 15a in the chamber of the upstream portion 15b is vertically downward in the vehicle-mounted state from the downstream end of the PCV valve, so that moisture contained in the blow-by gas condenses and the third gas passage Even when backflowing from 15, it can be prevented from adhering to the downstream end of the PCV valve.

  In addition, since the installation position of the opening is an intermediate position in the vertical direction of the chamber in a vehicle-mounted state, the casing of the PCV valve 14 can be used as a weir, and condensed moisture can be retained in the chamber, which is extremely low temperature. Even at that time, it is possible to prevent the downstream end of the PCV valve, the inside of the PCV valve, or the opening 15a in the chamber from being blocked by freezing of moisture.

  The upstream portion 15 b of the third gas passage extends to the mounting seat surface 401 of the surge tank mounting portion using the wall portion of the oil separation cover 10, and oil is present in the vicinity of the mounting portion between the oil separation cover 10 and the surge tank 7. The first opening 403 of the separation cover 10 and the second opening 7b which is the upstream end of the downstream portion 15c of the third gas passage of the surge tank 7 are in contact with each other. That is, the third gas passage 15 is formed by using an attachment portion between the oil separation cover 10 and the surge tank 7, and blow-by gas is returned to the surge tank 7 through this passage. A member to be externally connected is not required, and a reflux failure due to an assembly failure during manufacturing can be prevented.

  According to the present embodiment, the oil separation space OS, the PCV valve, and the third gas passage 15 can be positioned on the back surface of the intake unit IU and in the vicinity of the concave portion of the upper block, which is one side of the engine. It becomes possible to prevent moisture from freezing.

  Further, according to the present embodiment, it is possible to maintain a strong attachment property of a heavy object such as the electronically controlled throttle 6 even if the branched intake passage 8 is made of synthetic resin.

  As mentioned above, although the Example applied to the horizontal 4-cylinder engine was described, from the main point of this invention, the blowby gas recirculation apparatus of the engine of this invention is not limited to the said embodiment.

1 is a side view of an engine according to an embodiment of the present invention. It is the side view which looked at the upper block from the intake unit side. It is a bottom view of the upper block. It is a figure which shows the IV-IV sectional view in FIG. It is a figure which shows the VV sectional view in FIG. It is a figure which shows the VI-VI line cross section in FIG. FIG. 6 is a perspective view in which an oil separation cover is mounted on the intake unit side of the upper block. It is a figure which shows the principal part cross section by which the oil separation cover and the surge tank were connected by communication. It is a front view of an oil separation cover. It is a side view of the oil separation cover. It is a figure which shows the XI-XI line cross section of FIG. It is a figure which shows the XII-XII line cross section of FIG. It is a figure which shows the XIII-XIII line cross section of FIG.

Explanation of symbols

ENG Engine IU Intake unit CR Crank chamber OS Oil separation space 2 Upper block 6 Throttle body 8 Branch intake passage 10 Oil separation cover 11 First gas passage 12 Second gas passage 14 PCV valve 14a Blow-by gas introduction opening 15 Third gas passage 15a Opening 15b Upstream portion 300 of third gas passage 300 Chamber

Claims (3)

The engine blow-by gas is provided with a gas passage connecting the crank chamber of the engine and an intake system for supplying intake air via an oil separation space, and the blow-by gas generated from the engine is separated into oil and then supplied to the intake system. In the reflux device,
A PCV valve interposed in a gas passage part downstream of the oil separation space, the PCV valve having a downstream end positioned vertically above an upstream end;
A chamber formed vertically above and around the downstream portion of the PCV valve; and
An engine characterized in that an upstream end of a gas passage portion connected to an intake system downstream from the chamber communicates with the chamber at a position vertically below a downstream end of the PCV valve. Blow-by gas recirculation device.   The blow-by gas recirculation device for an engine according to claim 1, wherein an upstream end of a gas passage connected to the intake system is connected to the chamber at an intermediate position in the vertical direction of the chamber. The oil separation space is partitioned by a recess on one side of the engine body and an oil separation cover that covers the recess,
The PCV valve is mounted on the oil separation cover with the upstream side of the valve protruding into the oil separation space, and the chamber is formed between the oil separation cover and the PCV valve. The blow-by gas recirculation device for an engine according to claim 1 or 2.