Blow by passage cylinder head-Blow-by gas recirculating apparatus - Honda Giken Kogyo Kabushiki Kaisha

A blow-by gas passage system for an internal combustion engine of the V-type wherein longitudinally spaced passages are formed on each side of, and parallel to, the cylinders in each cylinder bank. Corresponding passages formed in each cylinder head allow for communication between the crankcase and a cavity formed in the space between the two banks of cylinders. An oil separator with a plurality of baffles arranged in a labyrinth-type fashion is mounted on top of the cylinder block and over the collection cavity. An intake manifold is mounted atop the oil separator and has an internal passage formed therethrough corresponding to the exit port of the oil separator. The other end of the intake manifold internal passage is fitted with a pcv -valve which is attached to a pipe leading to the engine air inlet passages of the intake manifold.

Blow by passage cylinder head

The blow-by gas distribution system of claim 1wherein the blow-by gas passageway comprises: a first blow-by channel formed in the center Free porn with hermathadites and connected to each of the intake runners formed in Blow by passage cylinder head runner shell; and. The blow-by gas return device of claim 5 wherein said oil separator is relatively flat and extends horizontally in both the longitudinal and lateral directions to substantially fill the space between the two banks of cylinders of the "V" type engine. Each of the nipples is mounted on a respective oil drain hole to surround the opening of the oil drain holewhich is protruded downwards. Lubrication oil is fed from the oil sump via a pump through pressurized passages to the cylinder block and the cylinder head. Effective date : Internal combustion engine having positioning pins disposed within fluid communication ports. Having fully described our invention, it is to be understood that we pasasge not to be limited to the details herein set forth pasage that our invention is of the full scope of the appended claims. Kato, H. When the Couple teen is ignited and exploded in an engine combustion chamber, gases are produced therein Blow by passage cylinder head the pressure in the combustion chamber is increased.

Will work for diapers. Latest Nissan Patents:

How do Blow by passage cylinder head clean it out? The ball hone tool, is […]. Showed up on time as scheduled. Related Stories. You're the best!!! When combustion takes place in the cylinder, the head gasket prevents the pressures created from escaping the cylinder through the space between the cylinder head and block. Because of this, a head gasket can fail in many different ways, with many different symptoms. Machine cover. Gather the necessary equipment. You may opt to have your cylinder heads hot tanked after cleaning them yourself to ensure your heads are as Naturist beach cornwall as possible. In some cases the piston rings may be leaking also, but you would get smoke all the time A Anonymous Dec 16, In this case, oil included in the reversely flowing blow-by gas introduced into the subsidiary Blow by passage cylinder head separation passage 13 can be well separated by the baffle plates 19 and 20 when flowing and moving up and down through the baffle plates.

The present application claims the priority to Korean Patent Application No.

  • Your mind starts reeling as the dollar signs begin to pile up.
  • Because it is directly involved in the connection between the engine block and cylinder heads, its function is critical to the proper operation of the engine.
  • The engine cylinder head has many passages for coolant and oil and can build up dirt over the life of the engine.
  • Posted by Calan , May 21,

Effective date : Year of fee payment : 4. Year of fee payment : 8. Year of fee payment : The distribution system includes an intake manifold configured to supply intake air to each cylinder of an engine; and a blow-by gas passageway formed within the intake manifold.

The blow-by gas passageway is configured to uniformly distribute blow-by gas, which is received through a blow-by gas return path, to each cylinder through the intake manifold.

Engine blow-by gas refers to all the gasses that are not exhausted through the exhaust manifold. Blow-by gas consists of combustion gasses that bypass the piston rings and enter the crankcase during engine operation. If the crankcase is not vented, this blow-by gas causes a build-up of pressure in the crankcase, resulting in damage to engine seals and environmental pollution through oil leaks and the escape of the blowby gas and atomized lubricants to the atmosphere.

For these reasons, many methods are used to remove blow-by gas. With the opening of the PCV valve, the blow-by gas enters the intake manifold to be supplied to the combustion chamber together with new intake air. There are two main considerations when installing a blow-by gas distribution system. The first is concerned with distribution, while the second is concerned with layout. Since blow-by gas is a type of impurity, many negative effects result if it is supplied together with new air into the combustion chamber.

Accordingly, it is necessary to optimize an installation location or pathway of a PCV valve [] , as well as where the blow-by gas enters an intake manifold With respect to layout, the blow-by gas distribution system often interferes with other elements.

In fact, interaction between the blow-by gas distribution system and other mechanisms may wear away protective coverings, etc. The blow-by gas distribution system of the present invention is preferably capable of equally distributing blow-by gas to each cylinder.

In a preferred embodiment of the present invention, the blow-by gas distribution system comprises an intake manifold, and a blow-by gas passageway. The intake manifold is configured to supply intake air to each cylinder of an engine. The blow-by gas passageway is formed within the intake manifold, and the blow-by gas passageway is configured to uniformly distribute blow-by gas to each cylinder, through the intake manifold. Preferably, the intake manifold comprises a plenum cap shell, a runner shell, and a center shell.

The plenum cap shell is fastened to one side of an engine throttle body, and the plenum cap shell is filled with air supplied from the throttle body. The runner shell is mounted between the plenum cap shell and intake holes of each cylinder of the engine, and is configured to supply intake air supplied to the plenum cap shell to each cylinder. The center shell is mounted between the plenum cap shell and the runner shell, and is configured to guide the intake air filled in the plenum cap shell to the runner shell.

It is preferable that the plenum cap shell is pan-shaped with a predetermined depth, and is separated into two spaces by a partitioning wall. It is further preferable that the two spaces of the plenum cap shell comprise a filling space, and a supply space. Air supplied from outside the intake manifold is filled into the filling space. The supply space is communicated with the center shell to supply air received from the center shell. Preferably, the communication of the filling space and the supply space is realized by an aperture formed in the partitioning wall, intake air supplied through the aperture being supplied to the runner shell via the center shell.

It is preferable that the runner shell is realized through a shape in which each of the intake runners is curved, one end of the runner shell being connected to a cylinder head, which is adjacent to a cylinder head cover, and its other end being connected to the center shell. Preferably, the center shell includes holes, which are formed at a location corresponding to the intake runners of the runner shell at an area adjacent to the runner shell.

It is preferable that the holes of the center shell comprise first holes, and second holes. It is further preferable that the blow-by gas passageway comprises first blow-by channel and a second blow-by channel. The first blow-by channel is formed in the center shell and connected to each of the intake runners formed in the runner shell.

The second blow-by channel is at a location of the plenum cap shell corresponding to the first blow-by channel such that the blow-bay gas passageway is realized through the combination of the first blow-by channel and the second blow-by channel.

Preferably, the blow-by gas passageway is formed such that its one end is closed while its other end is formed into a blow-by intake pipe that connects to a blowby gas return hose and protrudes from the intake manifold. It is further preferable that passage holes are formed in the blow-by gas passageway, and the passage holes communicate with the intake runners formed in the runner shell.

It is preferable that the blow-by gas passageway is connected to a blowby intake pipe that connects to a blow-by gas return hose, and the blow-by intake pipe is integrally formed with the intake manifold. In another preferred embodiment of the present invention, the blow-by gas distribution system for an engine comprises an intake manifold and a blow-by gas passageway.

The intake manifold is configured to supply intake air to each cylinder of said engine, and is provided with a plurality of intake runners defining air paths communicating with said cylinder of said engine.

The blow-by gas passageway is formed within said intake manifold, and is configured to supply blow-by gas to each air path of intake runners of said intake manifold through passage holes.

Each air path communicates with said blow-by gas passageway through each passage hole. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, serve to explain the principles of the invention.

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. A blow-by gas distribution system for an engine according to a preferred embodiment of the present invention will be described with reference to FIGS. A blow-by gas distribution system according to a preferred embodiment of the present invention includes a plastic intake manifold [] , and a blow-by gas passageway FIG.

The intake manifold has the shape shown in FIG. The intake manifold [] includes a plurality of intake runners , which form air intake paths.

In use, air passes through a throttle body, then through the air intake paths of the intake runners for transmission to a combustion chamber of the engine. The blow-by gas passageway [] is formed within the intake manifold to evenly distribute blow-by gas, which enters via a blow-by gas return path, to each cylinder through the intake manifold The blow-by gas passageway is preferably connected to a PCV valve not shown by a blow-by gas return hose not shown.

The intake manifold [] is structured using three different elements of a plenum cap shell , a runner shell , and a center shell The plenum cap shell is fastened to a part of an engine throttle body The plenum cap shell is filled with air supplied from the throttle body. Further, the plenum cap shell is made of plastic, and is pan-shaped with a predetermined depth.

As shown in FIG. The two spaces include a filling space into which air supplied from outside the intake manifold is filled, and a supply space communicated with the center shell to supply air received from the throttle body to the cylinders. The communication of the filling space and the supply space is realized by an aperture formed in the partitioning wall Intake air supplied through the aperture formed in the partitioning wall is supplied to the runner shell via the center shell The runner shell [] is mounted between the plenum cap shell and intake ports of each cylinder of the engine, and acts to supply intake air supplied to the plenum cap shell to each cylinder during intake strokes of the engine.

The runner shell [] is realized through a shape as shown in FIG. The center shell [] is mounted between the plenum cap shell and the runner shell , and acts to guide the intake air filled in the plenum cap shell to the runner shell The number of each of the first and second holes and corresponds to the number of cylinders for example, four of each of the first and second holes and for a 4-cylinder engine.

With reference to FIGS. The blow-by intake pipe is formed protruding from the intake manifold as shown in FIGS. In the preferred embodiment of the present invention, the intake manifold [] is made of plastic rather than the typical material of aluminum, and instead of a nipple, the blow-by intake pipe is integrally formed to the intake manifold As a result, a structure that connects each port to allow for closer proximity to the cylinder head cover is realized.

With such a configuration, a length of a blow-by hose is minimized to allow for a simple peripheral layout. Also, the formation or size of the holes may be varied as needed to enhance the distribution of the blow-by gas entering each cylinder.

Further, passage holes [] are formed in the blow-by gas channel as shown in FIG. Further, the passage holes are formed to allow for the uniform intake of blow-by gas into each cylinder. A size and direction of the passage holes may be varied according to the formation of the intake manifold and depending on engine characteristics. For example, the passage holes may be formed such that those close to the intake ports are small, and those further away become increasingly larger as the distance to the intake ports becomes greater.

In the intake manifold [] of the preferred embodiment of the present invention structured as in the above, blow-by gas entering into the blow-by gas passageway from the blow-by intake pipe is supplied uniformly to each cylinder through the intake runners after passing through the passage holes , to thereby improve the intake efficiency of all of the cylinders.

Further, since the blow-by gas passageway is formed by a combination of the first blow-by channel and the second blow-by channel of the plenum cap shell , only a small portion of the blow-by gas pathway, the blow-by-intake pipe , is protruded from a side of the plenum cap shell to thereby prevent any mechanical interference with external elements.

Accordingly, the uniform distribution of blow-by gas supplied to the runner shell is possible. In the distribution system for engine blow-by gas of the present invention, the distribution of blow-by gas to each cylinder is optimized such that engine performance is improved and NVH is minimized. Also, the layout of the blow-by gas distribution system is simplified. In addition, the nipple configuration used in conventional systems is omitted to thereby reduce costs associated with this element.

What is claimed is: 1. A blow-by gas distribution system for an engine comprising: an intake manifold configured to supply intake air to each cylinder of an engine; and. The blow-by gas distribution system of claim 1 , wherein the intake manifold comprises: a plenum cap shell fastened to one side of an engine throttle body, the plenum cap shell being filled with air supplied from the throttle body;. The blow-by gas distribution system of claim 2 , wherein the plenum cap shell is pan-shaped with a predetermined depth, and is separated into two spaces by a partitioning wall.

The blow-by gas distribution system of claim 3 , wherein the two spaces comprise: a filling space into which air supplied from outside the intake manifold is filled; and. The blow-by gas distribution system of claim 3 , wherein the communication of the filling space and the supply space is realized by an aperture formed in the partitioning wall, intake air supplied through the aperture being supplied to the runner shell via the center shell.

The blow-by gas distribution system of claim 2 , wherein the runner shell is realized through a shape in which each of the intake runners is curved, one end of the runner shell being connected to a cylinder head, which is adjacent to a cylinder head cover, and its other end being connected to the center shell.

The blow-by gas distribution system of claim 2 , wherein the center shell includes holes, which are formed at a location corresponding to the intake runners of the runner shell at an area adjacent to the runner shell. The blow-by gas distribution system of claim 1 , wherein the blow-by gas passageway comprises: a first blow-by channel formed in the center shell and connected to each of the intake runners formed in the runner shell; and.

The blow-by gas distribution system of claim 9 , wherein the blow-by gas passageway is formed such that its one end is closed while its other end is formed into a blow-by intake pipe that connects to a blow-by gas return hose and protrudes from the intake manifold.

The blow-by gas distribution system of claim 9 , wherein passage holes are formed in the blow-by gas passageway, the passage holes communicating with the intake runners formed in the runner shell. The blow-by gas distribution system of claim 1 , wherein the blow-by gas passageway is connected to a blow-by intake pipe that connects to a blow-by gas return hose, and the blow-by intake pipe is integrally formed with the intake manifold. A blow-by gas distribution system for an engine, comprising: an intake manifold configured to supply intake air to each cylinder of an engine, said intake manifold provided with a plurality of intake runners defining air paths communicating with said cylinder of said engine; and.

The blow-by gas distribution system of claim 13 , wherein the intake manifold comprises: a plenum cap shell fastened to one side of an engine throttle body, the plenum cap shell being filled with air supplied from the throttle body;. The blow-by gas distribution system of claim 14 , wherein the plenum cap shell is pan-shaped with a predetermined depth, and is separated into two spaces by a partitioning wall. The blow-by gas distribution system of claim 15 , wherein the two spaces comprise: a filling space into which air supplied from outside the intake manifold is filled; and.

The blow-by gas distribution system of claim 15 , wherein the communication of the filling space and the supply space is realized by an aperture formed in the partitioning wall, intake air supplied through the aperture being supplied to the runner shell via the center shell.

The blow-by gas distribution system of claim 14 , wherein the runner shell is realized through a shape in which each of the intake runners is curved, one end of the runner shell being connected to a cylinder head, which is adjacent to a cylinder head cover, and its other end being connected to the center shell.

The blow-by gas distribution system of claim 14 , wherein the center shell includes holes, which are formed at a location corresponding to the intake runners of the runner shell at an area adjacent to the runner shell.

May 21, 1. Heat Transfer Head gaskets allow heat to move between the engine block and cylinder heads by allowing heat to move freely through the gasket material. One classic sign is white, coolant-smelling fog coming from the tailpipe. The best an external inspection can do is determine the problem is head gasket related. If not, unplug the fuel injectors, or disconnect the carburetor fuel line and drain the carburetor fuel bowl. The numbers on the picture represent possible locations for each type of failure described, but keep in mind that failures can happen in many other areas of the gasket as well.

Blow by passage cylinder head

Blow by passage cylinder head

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I have already scheduled a future service with Nicholas and will schedule any and all future repairs with him if he is available. Need Help With Your Car? Related articles. The sun catches and Here, blow-by gas is a gas blowing into a crank case through spaces between the pistons and the cylinders during compression and explosion strokes and including non-combustion components such as HC, CO, etc.

In general, the blow-by gas flowing passages for an internal combustion engine are formed to separate or remove engine oil lubricant from blow-by gas and further to return the blow-by gas into the intake system.

Further, since a fairly large amount of engine oil is included in the above-mentioned blow-by gas, in general some oil separating means are provided in the blow-by gas passage formed within the cylinder cover head, in order to prevent engine oil from being introduced into the intake passage.

In this prior-art cylinder head cover, although a blow-by gas outlet is provided, since no external air inlet is formed, external air is directly introduced into the crank case of the internal combustion engine, and then the blow-by gas rising up through scavenging holes formed in the cylinder block and the cylinder-head is returned to the intake passage through the blow-by gas outlet.

In this prior-art structure, however, when the engine is running at high speed under heavy load, since pressure difference between the upstream side and the downstream of the throttle valve decreases, and further the amount of blow-by gas increases, there exists a problem in that blow-by gas flows through the external air passage in the reverse direction to the upstream side of the throttle valve in the intake passage, so that blown-by gas including engine oil is introduced into engine combustion chambers together with external intake air.

Therefore, where only the blow-by gas outlet and the oil separating means are provided in the cylinder head cover as in the prior-art case, without due consideration of the reversely flowing blown-by gas at high engine speed and under heavy load, it is inevitably necessary to provide an additional oil separating means at the external air inlet port on the crank case side, thus raising a problem in that the engine structure is rather complicated.

With these problems in mind, therefore, it is the primary object of the present invention to provide a cylinder head cover in which an external air inlet and a blow-by gas outlet are both formed in a small space of the cylinder head cover at two relatively ideal locations, and further two oil separating means for both the forward flowing blow-by gas and the reversely flowing blown-by gas are effectively provided in the cylinder head cover, in order to improve scavenging efficiency such that blow-by gas within the crank case can be effectively replaced with external air and to improve engine oil separation efficiency such that engine oil included in blown-by gas flowing in the reverse direction at high engine speed and heavy load can be effectively separated or removed without feeding engine oil into the intake passage.

Further, the engine cylinder head comprises: a plurality of blow-by gas passage baffle plates 36, 37 alternately arranged in said main oil-separation passage 26 so as to extend from above and below in such a way that blow-by gas flows therethrough being moved up and down along said baffle plates to separate oil included in blow-by gas flowing from said blow-by gas inlet to said blow-by gas outlet under normal engine operating conditions, and a plurality of air passage baffle plates 19, 20 alternately arranged in said subsidiary oil-separation passage 13 so as to extend from above and below in such a way that external air flows therethrough being moved up and down along said baffle plates to separate oil included in blow-by gas reversely flowing from said external air outlet to said external air inlet when an engine is running at high speed and under heavy load.

The subsidiary oil-separation passage 3 is sloped down from a U-shaped connection end between said external air passage and said subsidiary oil-separation passage to said external air outlet 21 , and the main oil-separation passage 25 is sloped up from said blow-by gas inlet 38 to a U-shaped connection end between said main oil-separation passage and said gas passage.

In the cylinder head cover according to the present invention, external air introduced from the upstream side of the intake passage through the external air inlet 16 flows through the external air passage 12 along the middle longitudinal recessed portion 4. After having been U-turned, the external air flows through the subsidiary oil-separation passage 13 to the external air outlet 21 and further into the crank case through scavenging holes formed in the cylinder head and the cylinder block, to replace blow-by gas introduced into the crank case through the spaces between the engine cylinders and the pistons with the introduced external air.

The blow-by gas replaced with the external air rises upward through the scavenging holes formed in the cylinder block and the cylinder head or through the chain casing, and further flows through the blow-by gas inlet 38 to the main oil-separation passage After having been U-turned, the blowing gas flows through the blow-by gas passage 25 and a transversal gas passage 29 to the blow-by gas outlet The blow-by gas fed out of the blow-by gas outlet 30 is introduced into the surge tank 31a on the downstream side of the intake system for air pollution prevention.

In the above-mentioned arrangement, since the external air outlet 21 and the blow-by gas inlet 38 are located in diagonally furthest positioned relationship with respect to each other within the cylinder head cover, it is possible to effectively prevent external gas from directly flowing into the blow-by gas inlet 38 , thus improving the blow-by gas replacement efficiency.

On the other hand, when the amount of blow-by gas increases at high engine speed and under heavy load, blow-by gas flows in the reverse direction from the external air inlet 16 to the engine intake passage. In this case, however since the blow-by gas is allowed to be passed reversely through the subsidiary oil-separation passage, it is possible to effectively separate oil included in the reversely flowing blown-by gas, thus preventing engine oil from being returned into the engine intake passage.

An embodiment of the cylinder head cover for a four series-connected DOHC double overhead camshaft internal combustion engine will be described hereinbelow by way of example, with reference to the attached drawings. External air is introduced into the engine 2 by way of an air cleaner 33, an intake duct 18, a throttle chamber 17, a surge tank 31a, and four intake manifolds Further, external air is introduced into under the engine cylinder head cover 1 from the intake duct 18 via an air tube 42 and a head cover external air inlet 16, in order to scavenge blow-by gas entering into a crank case not shown by displacement of the blow-by gas with external air introduced through the air tube The scavenged blow-by gas is fed into the surge tank 31a through a blow-by gas outlet 30 and a pressure control valve PCV 40, in order to recycle the blow-by gas for air pollution prevention.

Further, in FIG. With reference to the attached drawings, in particular FIGS. External air introduced from the intake duct 18 shown in FIG. The external air thus introduced is further fed into a crank case through scavenging holes formed in a cylinder head and a cylinder block both not shown to scavenge blow-by gas introduced into the crank case through spaces between the engine cylinders and the pistons by the introduced external air.

The blow-by gas is replaced with the external air and rises upward from the crank case to the cylinder head cover 1. Thereafter, blow-by gas introduced from the crank case to the blow-by gas inlet 38 flows through a space 6 shown in FIG. The above longitudinal recessed portion 4 divides the cylinder head cover 1 into a first longitudinal space 5 for covering an intake-side camshaft and a second longitudinal space 6 for covering an exhaust-side camshaft. Further, as shown in FIG.

As depicted in FIG. Further, another transversal partition wall 14a is formed between an oil insertion hole 41 to which an oil filler cap not shown is attached and the U-shaped external air passage These two partition walls 14a and 14b are die-casted integral with the cylinder head cover 1.

Further, these external air passage 12 and the subsidiary oil-separation passage 13 are both covered by a metallic under cover 15, as shown in FIGS.

The external air passage 12 is formed along the wall surface of the recessed groove portion 4 and connected to the metallic tube external air inlet 16 on one end side thereof remote from the chain casing 3.

The external air inlet 16 is connected to the intake duct 18 via the air tube 42 on the upstream side of the throttle chamber 17 in the intake passage. The above subsidiary oil-separation passage 13 is provided with two baffle plates 19 fixed to the cylinder head cover 1 and a single baffle plate 20 fixed to the under cover 15 as depicted in FIG. The end portion of the subsidiary oil-separation passage 13 is open to an external air outlet 21 shown in FIGS.

On the other hand, as depicted in FIG. These two partition walls 27a and 27b are also die-casted integral with the cylinder head cover 1. Further, these blow-by gas passage 25 and the main oil-separation passage 26 are both covered by another metallic under cover 28, as shown in FIGS.

The blow-by gas passage 25 is formed along the wall surface of the recessed groove portion 4 and connected at one end thereof to a transversal blow-by gas passage 29 formed by the two longitudinal partition walls 27c and 27d and the under cover 28 so as to extend along the chain casing 3. The transversal gas passage 29 is connected to the metallic blow-by gas outlet 30 provided on the side surface of the cylinder head cover so as to communicate with the surge tank 31a via the PCV valve 40 and the gas tube 32 on the downstream side of the throttle chamber 17 in the intake passage, as shown in FIG.

The above main oil-separation passage 26 is provided with three baffle plates 36 fixed to the cylinder head cover 1 and two baffle plates 37 fixed to the under cover 28 as depicted in FIG. The start portion of the main oil-separation passage 26 is open to the blow-by gas inlet 38 shown in FIG.

The function of the engine cylinder head cover according to the present invention will be described hereinbelow.

USB2 - Device for separating oil from blow-by gas - Google Patents

To scavenge blow-by gas blown into a crank case with newly introduced external air at high replacement efficiency and further to provide oil separating baffle plates at both the main oil-separation passage and the subsidiary oil separation passage used when blow-by gas follows in the reverse direction from the external air outlet to the external air inlet , the external air outlet and the blow-by gas inlet are located in diagonally furthest positional relationship with respect to each other within the cylinder head cover; and further a U-shaped blow-by gas passage including the main oil-separation passage is arranged on one longitudinal space of the head cover and another U-shaped external air passage including the subsidiary oil-separation passage is also arranged on the other longitudinal space of the head cover.

Here, blow-by gas is a gas blowing into a crank case through spaces between the pistons and the cylinders during compression and explosion strokes and including non-combustion components such as HC, CO, etc.

In general, the blow-by gas flowing passages for an internal combustion engine are formed to separate or remove engine oil lubricant from blow-by gas and further to return the blow-by gas into the intake system.

Further, since a fairly large amount of engine oil is included in the above-mentioned blow-by gas, in general some oil separating means are provided in the blow-by gas passage formed within the cylinder cover head, in order to prevent engine oil from being introduced into the intake passage.

In this prior-art cylinder head cover, although a blow-by gas outlet is provided, since no external air inlet is formed, external air is directly introduced into the crank case of the internal combustion engine, and then the blow-by gas rising up through scavenging holes formed in the cylinder block and the cylinder-head is returned to the intake passage through the blow-by gas outlet.

In this prior-art structure, however, when the engine is running at high speed under heavy load, since pressure difference between the upstream side and the downstream of the throttle valve decreases, and further the amount of blow-by gas increases, there exists a problem in that blow-by gas flows through the external air passage in the reverse direction to the upstream side of the throttle valve in the intake passage, so that blown-by gas including engine oil is introduced into engine combustion chambers together with external intake air.

Therefore, where only the blow-by gas outlet and the oil separating means are provided in the cylinder head cover as in the prior-art case, without due consideration of the reversely flowing blown-by gas at high engine speed and under heavy load, it is inevitably necessary to provide an additional oil separating means at the external air inlet port on the crank case side, thus raising a problem in that the engine structure is rather complicated.

With these problems in mind, therefore, it is the primary object of the present invention to provide a cylinder head cover in which an external air inlet and a blow-by gas outlet are both formed in a small space of the cylinder head cover at two relatively ideal locations, and further two oil separating means for both the forward flowing blow-by gas and the reversely flowing blown-by gas are effectively provided in the cylinder head cover, in order to improve scavenging efficiency such that blow-by gas within the crank case can be effectively replaced with external air and to improve engine oil separation efficiency such that engine oil included in blown-by gas flowing in the reverse direction at high engine speed and heavy load can be effectively separated or removed without feeding engine oil into the intake passage.

Further, the engine cylinder head comprises: a plurality of blow-by gas passage baffle plates 36, 37 alternately arranged in said main oil-separation passage 26 so as to extend from above and below in such a way that blow-by gas flows therethrough being moved up and down along said baffle plates to separate oil included in blow-by gas flowing from said blow-by gas inlet to said blow-by gas outlet under normal engine operating conditions, and a plurality of air passage baffle plates 19, 20 alternately arranged in said subsidiary oil-separation passage 13 so as to extend from above and below in such a way that external air flows therethrough being moved up and down along said baffle plates to separate oil included in blow-by gas reversely flowing from said external air outlet to said external air inlet when an engine is running at high speed and under heavy load.

The subsidiary oil-separation passage 3 is sloped down from a U-shaped connection end between said external air passage and said subsidiary oil-separation passage to said external air outlet 21 , and the main oil-separation passage 25 is sloped up from said blow-by gas inlet 38 to a U-shaped connection end between said main oil-separation passage and said gas passage.

In the cylinder head cover according to the present invention, external air introduced from the upstream side of the intake passage through the external air inlet 16 flows through the external air passage 12 along the middle longitudinal recessed portion 4.

After having been U-turned, the external air flows through the subsidiary oil-separation passage 13 to the external air outlet 21 and further into the crank case through scavenging holes formed in the cylinder head and the cylinder block, to replace blow-by gas introduced into the crank case through the spaces between the engine cylinders and the pistons with the introduced external air.

The blow-by gas replaced with the external air rises upward through the scavenging holes formed in the cylinder block and the cylinder head or through the chain casing, and further flows through the blow-by gas inlet 38 to the main oil-separation passage After having been U-turned, the blowing gas flows through the blow-by gas passage 25 and a transversal gas passage 29 to the blow-by gas outlet The blow-by gas fed out of the blow-by gas outlet 30 is introduced into the surge tank 31a on the downstream side of the intake system for air pollution prevention.

In the above-mentioned arrangement, since the external air outlet 21 and the blow-by gas inlet 38 are located in diagonally furthest positioned relationship with respect to each other within the cylinder head cover, it is possible to effectively prevent external gas from directly flowing into the blow-by gas inlet 38 , thus improving the blow-by gas replacement efficiency.

On the other hand, when the amount of blow-by gas increases at high engine speed and under heavy load, blow-by gas flows in the reverse direction from the external air inlet 16 to the engine intake passage. In this case, however since the blow-by gas is allowed to be passed reversely through the subsidiary oil-separation passage, it is possible to effectively separate oil included in the reversely flowing blown-by gas, thus preventing engine oil from being returned into the engine intake passage.

An embodiment of the cylinder head cover for a four series-connected DOHC double overhead camshaft internal combustion engine will be described hereinbelow by way of example, with reference to the attached drawings. External air is introduced into the engine 2 by way of an air cleaner 33, an intake duct 18, a throttle chamber 17, a surge tank 31a, and four intake manifolds Further, external air is introduced into under the engine cylinder head cover 1 from the intake duct 18 via an air tube 42 and a head cover external air inlet 16, in order to scavenge blow-by gas entering into a crank case not shown by displacement of the blow-by gas with external air introduced through the air tube The scavenged blow-by gas is fed into the surge tank 31a through a blow-by gas outlet 30 and a pressure control valve PCV 40, in order to recycle the blow-by gas for air pollution prevention.

Further, in FIG. With reference to the attached drawings, in particular FIGS. External air introduced from the intake duct 18 shown in FIG.

The external air thus introduced is further fed into a crank case through scavenging holes formed in a cylinder head and a cylinder block both not shown to scavenge blow-by gas introduced into the crank case through spaces between the engine cylinders and the pistons by the introduced external air.

The blow-by gas is replaced with the external air and rises upward from the crank case to the cylinder head cover 1. Thereafter, blow-by gas introduced from the crank case to the blow-by gas inlet 38 flows through a space 6 shown in FIG. The above longitudinal recessed portion 4 divides the cylinder head cover 1 into a first longitudinal space 5 for covering an intake-side camshaft and a second longitudinal space 6 for covering an exhaust-side camshaft.

Further, as shown in FIG. As depicted in FIG. Further, another transversal partition wall 14a is formed between an oil insertion hole 41 to which an oil filler cap not shown is attached and the U-shaped external air passage These two partition walls 14a and 14b are die-casted integral with the cylinder head cover 1.

Further, these external air passage 12 and the subsidiary oil-separation passage 13 are both covered by a metallic under cover 15, as shown in FIGS. The external air passage 12 is formed along the wall surface of the recessed groove portion 4 and connected to the metallic tube external air inlet 16 on one end side thereof remote from the chain casing 3.

The external air inlet 16 is connected to the intake duct 18 via the air tube 42 on the upstream side of the throttle chamber 17 in the intake passage. The above subsidiary oil-separation passage 13 is provided with two baffle plates 19 fixed to the cylinder head cover 1 and a single baffle plate 20 fixed to the under cover 15 as depicted in FIG.

The end portion of the subsidiary oil-separation passage 13 is open to an external air outlet 21 shown in FIGS. On the other hand, as depicted in FIG.

These two partition walls 27a and 27b are also die-casted integral with the cylinder head cover 1. Further, these blow-by gas passage 25 and the main oil-separation passage 26 are both covered by another metallic under cover 28, as shown in FIGS.

The blow-by gas passage 25 is formed along the wall surface of the recessed groove portion 4 and connected at one end thereof to a transversal blow-by gas passage 29 formed by the two longitudinal partition walls 27c and 27d and the under cover 28 so as to extend along the chain casing 3. The transversal gas passage 29 is connected to the metallic blow-by gas outlet 30 provided on the side surface of the cylinder head cover so as to communicate with the surge tank 31a via the PCV valve 40 and the gas tube 32 on the downstream side of the throttle chamber 17 in the intake passage, as shown in FIG.

The above main oil-separation passage 26 is provided with three baffle plates 36 fixed to the cylinder head cover 1 and two baffle plates 37 fixed to the under cover 28 as depicted in FIG. The start portion of the main oil-separation passage 26 is open to the blow-by gas inlet 38 shown in FIG.

The function of the engine cylinder head cover according to the present invention will be described hereinbelow. When the engine is running at ordinary speed and under ordinary load, external air is introduced through the external air inlet 16, passed through the external air passage 12 so as to cool the middle longitudinal recessed portion 4, turned along the U-shaped passage through the subsidiary oil-separation passage 13, and introduced into the valve chamber through the external air outlet 21 and further into the crank case through scavenge holes not shown formed in the cylinder head and the cylinder block in order to scavenge the valve chamber and the crank case by the external air.

Blow-by gas replaced with the external air thus introduced are collected into under the cylinder cover head 1 through scavenge holes and the chain chamber formed on the engine side end, and introduced through the blow-by gas inlet 38 to the main oil separation passage In the cylinder head cover 1 according to the present invention, since the blow-by gas inlet 38 is located diagonal with respect to or at such a position the furthest away from the external air outlet 21 i.

In other words, it is possible to obtain a higher scavenging efficiency and a higher replacement efficiency of the blow-by gas with the external air. Oil included in the blow-by gas introduced into the main oil separation passage 26 is separated by the baffle plates 36 and 37 when flowing and moving up and down through the baffle plates. Further, the blow-by gas is turned along the U-shape passage and flows through the blow-by gas passage 25 and the blow-by gas transversal passage 29 to the surge tank 31a via the blow-by gas outlet In the above-mentioned blow-by gas passage, since the main oil separation passage 26 is sufficiently long, it is possible to well separate oil from the blown-by gas.

In addition, since the blow-by gas is well cooled by the external air when passing through the main oil separation passage 26 formed near the outside of the cylinder cover head 1 and therefore the temperature of the blow-by gas is cooled low, when passing through the gas passage 25, the middle recessed portion 4 along which the ignition plug insertion holes 8 are arranged is not heated.

Therefore, it is possible to keep the middle recessed portion 4 at relatively low temperature in cooperation of the cooling function of the external air flowing through the external air passage Thus improving the service life of the sealing rubber ring Further, oil separated from the main oil separation passage 26 is discharged through the oil discharge port 39, and only the remaining oil is returned to the valve chamber through the blow-by gas inlet On the other hand, when the engine is running at high speed and under heavy load, the amount of blow-by gas increases, so that the blow-by gas flows in the reverse direction and fed out through the external air passage That is, blown-by gas is introduced from the external air outlet 21, passed through the subsidiary oil separation passage 13 in the reverse direction, and returned to the intake duct 18 on the upstream side of the throttle chamber 17 via the external air passage 12, the external air inlet 16 and the air tube In this case, oil included in the reversely flowing blow-by gas introduced into the subsidiary oil separation passage 13 can be well separated by the baffle plates 19 and 20 when flowing and moving up and down through the baffle plates.

In particular, since the subsidiary oil separation passage 13 is sufficiently long as that of the main oil separation passage 26, it is possible to sufficiently separate oil from the blown-by gas. In the engine cylinder head cover of the present invention, since engine oil included in blow-by gas can be well separated before the blow-by gas is fed out through both the blow-by gas outlet 30 and the external air inlet 6 to the intake passage, it is possible to securely to prevent oil lubricant from entering the engine intake system, without excessively increasing the size of the cylinder head cover, because the oil separation passages 13 and 26 are both formed in U-shaped fashion within small and narrow spaces 5 and 6 partitioned by the middle longitudinal recessed portion 4 within the engine cylinder head cover.

As described above, in the engine cylinder head cover for an internal combustion engine according to the present invention, since the external air outlet and the blow-by gas inlet both open to the valve chamber are located diagonal with respect to or the furthest away from each other, it is possible to efficiently scavenge the crank case by introduced external air and therefore to improve the replacement efficiency of the blow-by gas with the introduced external air.

Further, since oil included in blow-by gas can be separated before fed out through the blow-by gas outlet at the ordinary engine speed and load and through the external air inlet at the high engine speed and under heavy load by forming a sufficiently long main and subsidiary oil-separation passages, it is possible to effectively separate oil from blow-by gas.

An engine cylinder head cover formed with a chain casing and a middle longitudinal recessed portion extending along a cylinder arrangement direction, comprising:. The engine cylinder head cover of claim 1, which further comprises: a plurality of blow-by gas passage baffle plates alternately arranged in said main oil-separation passage so as to extend from above and below in such a way that blow-by gas flows therethrough being moved up and down along said baffle plates to separate oil included in blow-by gas flowing from said blow-by gas inlet to said blow-by gas outlet under normal engine operating conditions.

The engine cylinder head cover of claim 1, which further comprises: a plurality of air passage baffle plates alternately arranged in said subsidiary oil-separation passage so as to extend from above and below in such a way that external air flows therethrough being moved up and down along said baffle plates to separate oil included in blow-by gas reversely flowing from said external air outlet to said external air inlet when an engine is running at high speed and under heavy load.

The engine cylinder head cover of claim 1, wherein said subsidiary oil-separation passage is sloped down from a U-shaped connection end between said external air passage and said subsidiary oil-separation passage to said external air outlet.

The engine cylinder head cover of claim 1, wherein said main oil-separation passage is sloped up from said blow-by gas inlet to a U-shaped connection end between said main oil-separation passage and said gas passage.

The engine cylinder head cover of claim 1, which further comprises an oil discharge part formed in said main oil-separation passage. The engine cylinder head cover of claim 1, which further comprises a transversal blow-by gas passage 29 connected between said blow-by gas passage and said blow-by gas outlet.

May 11, - Nissan. Latest Nissan Patents:. Incentivized group shipping system Fuel cell system and control method for fuel cell system Cooling circuit for internal combustion engines Information providing method for vehicle and information providing device for vehicle Control device for internal combustion engine. Description of the Prior Art In general, the blow-by gas flowing passages for an internal combustion engine are formed to separate or remove engine oil lubricant from blow-by gas and further to return the blow-by gas into the intake system.

SUMMARY OF THE INVENTION With these problems in mind, therefore, it is the primary object of the present invention to provide a cylinder head cover in which an external air inlet and a blow-by gas outlet are both formed in a small space of the cylinder head cover at two relatively ideal locations, and further two oil separating means for both the forward flowing blow-by gas and the reversely flowing blown-by gas are effectively provided in the cylinder head cover, in order to improve scavenging efficiency such that blow-by gas within the crank case can be effectively replaced with external air and to improve engine oil separation efficiency such that engine oil included in blown-by gas flowing in the reverse direction at high engine speed and heavy load can be effectively separated or removed without feeding engine oil into the intake passage.

Referenced Cited. Patent Documents April 29, Ohmi et al. Patent History. Current U. Justia Legal Resources. Find a Lawyer. Law Students. US Federal Law.

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Blow by passage cylinder head