BLOW-BY GAS PROCESSING DEVICE

Abstract

A blow-by gas processing device is configured to allow a crankcase and a downstream side of a throttle valve of an intake system to communicate to introduce blow-by gas into the intake system. The device includes a positive crankcase ventilation ( ) valve, a PCV valve cover, and a PCV hose. The valve is attached to a cylinder block and adjusts a flow rate of the blow-by gas. The valve cover is coaxially with the valve and is attached to the cylinder block to cover the valve. The hose is coupled to the valve cover and allows the valve cover and the intake system to communicate. An inner diameter of the valve cover on a tip end side with respect to a plane including a tip end surface of the valve is greater than that on a base end side with respect to the plane.

Claims

1. A blow-by gas processing device configured to allow a crankcase and a downstream side of a throttle valve of an intake system to communicate with each other to introduce blow-by gas into the intake system, the blow-by gas processing device comprising: a positive crankcase ventilation valve attached to a cylinder block, the positive crankcase ventilation valve being configured to adjust a flow rate of the blow-by gas according to a pressure of the intake system; a positive crankcase ventilation valve cover disposed coaxially with the positive crankcase ventilation valve, the positive crankcase ventilation valve cover being attached to the cylinder block so as to cover the positive crankcase ventilation valve; and a positive crankcase ventilation hose coupled to the positive crankcase ventilation valve cover, the positive crankcase ventilation hose being configured to allow the positive crankcase ventilation valve cover and the intake system to communicate with each other, wherein an inner diameter of the positive crankcase ventilation valve cover on a tip end side with respect to a plane including a tip end surface of the positive crankcase ventilation valve is greater than an inner diameter of the positive crankcase ventilation valve cover on a base end side with respect to the plane including the tip end surface of the positive crankcase ventilation valve.

2. The blow-by gas processing device according to claim 1, wherein the positive crankcase ventilation valve cover comprises a base end portion and a great diameter portion having a greater inner diameter than an inner diameter of the base end portion, and each of the base end portion and the great diameter portion has a cylindrical shape or a rectangular tubular shape.

3. A blow-by gas processing device configured to allow a crankcase and a downstream side of a throttle valve of an intake system to communicate with each other to introduce blow-by gas into the intake system, the blow-by gas processing device comprising: a positive crankcase ventilation valve attached to a cylinder block, the positive crankcase ventilation valve being configured to adjust a flow rate of the blow-by gas according to a pressure of the intake system; a tubular positive crankcase ventilation valve cover attached to the cylinder block so as to cover the positive crankcase ventilation valve; and a positive crankcase ventilation hose coupled to the positive crankcase ventilation valve cover, the positive crankcase ventilation hose being configured to allow the positive crankcase ventilation valve cover and the intake system to communicate with each other, wherein a center axis of the positive crankcase ventilation valve cover is shifted to a front side of a vehicle with respect to a center axis of the positive crankcase ventilation valve.

4. The blow-by gas processing device according to claim 1, wherein the positive crankcase ventilation valve and the positive crankcase ventilation valve cover are attached to an upper surface of the cylinder block such that an axial line of the positive crankcase ventilation valve and an axial line of the positive crankcase ventilation valve cover are parallel with a vertical direction.

5. The blow-by gas processing device according to claim 3, wherein the positive crankcase ventilation valve and the positive crankcase ventilation valve cover are attached to an upper surface of the cylinder block such that an axial line of the positive crankcase ventilation valve and an axial line of the positive crankcase ventilation valve cover are parallel with a vertical direction.

6. The blow-by gas processing device according to claim 4, wherein the positive crankcase ventilation valve cover has such an inner diameter that an engine is stopped or the engine is not startable when the positive crankcase ventilation valve cover is detached.

7. The blow-by gas processing device according to claim 5, wherein the positive crankcase ventilation valve cover has such an inner diameter that an engine is stopped or the engine is not startable when the positive crankcase ventilation valve cover is detached.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the specification, serve to describe the principles of the disclosure.

[0007] FIG. 1 is a view illustrating the configuration of an engine to which a blow-by gas processing device according to an embodiment is applied.

[0008] FIG. 2 is a cross-sectional view illustrating the configuration of a main portion of the blow-by gas processing device according to the first embodiment.

[0009] FIG. 3 is a cross-sectional view illustrating the configuration of a main portion of a blow-by gas processing device according to an embodiment.

DETAILED DESCRIPTION

[0010] The blow-by gas processing device has, for example, a scavenging line (PCV line) configured to allow the inside of the crankcase and the downstream side of a throttle valve to communicate with each other to introduce (recirculate) the blow-by gas to the intake system, a positive crankcase ventilation (PCV) valve configured to adjust the flow rate of the blow-by gas flowing through the scavenging line, and a fresh air line configured to allow the upstream side of the throttle valve and the inside of the crankcase to communicate with each other to introduce fresh air.

[0011] For example, according to On-Board Diagnostics Second Generation (OBD2) in North America, prevention of detachment of the PCV valve and detection of the detachment of the PCV valve when the PCV valve is detached have been demanded.

[0012] In order to comply with the laws and regulations described above, for example, it may be conceived that a cover is provided such that the PCV valve cannot be detached from the cylinder block. In this case, a turbid solution mixed with condensed water or the like generated by condensation of oil contained in the blow-by gas or moisture (water vapor) contained in the blow-by gas may be accumulated between the PCT valve and the cover. Then, during acceleration, deceleration, or turning of the vehicle, when the liquid surface of the turbid solution tilts due to longitudinal acceleration (longitudinal G) or lateral acceleration (lateral G) and the turbid solution together flows into the PCT valve, the turbid solution may be suctioned into the engine along the flow of the blow-by gas, which may result in deterioration of the engine combustion.

[0013] It is desirable to provide a blow-by gas processing device that can comply with laws and regulations on detachment of the PCV valve, and that prevents (or reduces) a turbid solution mixed with condensed water or the like generated by condensation of oil contained in the blow-by gas or moisture contained in the blow-by gas from together flowing into the PCV valve.

[0014] In the following, some embodiments of the disclosure are described in detail with reference to the accompanying drawings. Note that the following description is directed to illustrative examples of the disclosure and not to be construed as limiting to the disclosure. Factors including, without limitation, numerical values, shapes, materials, components, positions of the components, and how the components are coupled to each other are illustrative only and not to be construed as limiting to the disclosure. Further, elements in the following example embodiments which are not recited in a most-generic independent claim of the disclosure are optional and may be provided on an as-needed basis. The drawings are schematic and are not intended to be drawn to scale. Throughout the present specification and the drawings, elements having substantially the same function and configuration are denoted with the same numerals to avoid any redundant description.

First Embodiment

[0015] First, the configuration of a blow-by gas processing device 60 according to a first embodiment will be described with reference to both FIGS. 1 and 2. FIG. 1 is a view illustrating the configuration of an engine 10 to which the blow-by gas processing device 60 is applied.

[0016] FIG. 2 is a cross-sectional view illustrating the configuration of a main portion (a PCV valve 62, a PCV valve cover 65, and the like) of the blow-by gas processing device 60.

[0017] The engine 10 may be of any model, but is a horizontally opposed four-cylinder gasoline engine, for example. Moreover, the engine 10 is a cylinder injection engine configured to directly inject fuel into a cylinder (tube). In the engine 10, air suctioned through an air cleaner 16 is throttled by an electronically controlled throttle valve (hereinafter merely referred to as a throttle valve) 13 provided for an intake pipe 15, passes through an intake manifold 11, and is then suctioned into each cylinder provided in the engine 10. In one embodiment, the intake pipe 15 and the intake manifold 11 may serve as an intake system.

[0018] The amount of air suctioned through the air cleaner 16 is detected by an airflow meter 14 disposed between the air cleaner 16 and the throttle valve 13. A vacuum sensor 30 configured to detect a pressure (intake manifold pressure) in the intake manifold 11 is disposed in a collector (surge tank) forming the intake manifold 11. Further, a throttle opening degree sensor 31 configured to detect the opening degree of the throttle valve 13 is disposed for the throttle valve 13.

[0019] A cylinder head has an intake port 22 and an exhaust port 23 for each cylinder. It is noted that FIG. 1 illustrates one bank. For the intake port 22 and the exhaust port 23, an intake valve 24 and an exhaust valve 25 configured to open and close the intake port 22 and the exhaust port 23 are provided. Between an intake cam shaft and an intake cam pulley configured to drive the intake valve 24, a variable valve timing mechanism 26 is disposed, which is configured to continuously change the rotation phase (displacement angle) of the intake cam shaft relative to a crankshaft 10a by turning the intake cam pulley and the intake cam shaft relative to each other to advance and delay the valve timing (opening/closing timing) of the intake valve 24. This variable valve timing mechanism 26 variably sets the opening/closing timing of the intake valve 24 according to an engine operation state.

[0020] Similarly, between an exhaust cam shaft and an exhaust cam pulley, a variable valve timing mechanism 27 is disposed, which is configured to continuously change the rotation phase (displacement angle) of the exhaust cam shaft relative to the crankshaft 10a by turning the exhaust cam pulley and the exhaust cam shaft relative to each other to advance and delay the valve timing (opening/closing timing) of the exhaust valve 25. This variable valve timing mechanism 27 variably sets the opening/closing timing of the exhaust valve 25 according to the engine operation state.

[0021] An injector 12 configured to inject fuel into the cylinder is attached to each cylinder of the engine 10. The injector 12 directly injects fuel pressurized by a high-pressure fuel pump (not illustrated) into a combustion chamber of each cylinder.

[0022] An ignition plug 17 configured to ignite an air-fuel mixture and an ignitor-equipped coil 21 configured to apply a high voltage to the ignition plug 17 are attached to the cylinder head of each cylinder. In each cylinder of the engine 10, the air-fuel mixture of the suctioned air and the fuel injected by the injector 12 is ignited and combusted by the ignition plug 17. After the combustion, exhaust gas is discharged through an exhaust pipe 18.

[0023] An air-fuel ratio sensor 19 is attached downstream of a joint portion of the exhaust pipes 18 and upstream of an exhaust purification catalyst 20. As the air-fuel ratio sensor 19, a linear air-fuel ratio sensor (LAF sensor) is used, which is capable of outputting a signal (that is, a signal corresponding to the air-fuel ratio of the air-fuel mixture) corresponding to an oxygen concentration and an unburnt gas concentration in the exhaust gas and linearly detecting the air-fuel ratio.

[0024] The exhaust purification catalyst 20 is disposed downstream of the LAF sensor 19. The exhaust purification catalyst 20 is a three-way catalyst, and is configured to simultaneously perform oxidization of hydrocarbon (HC) and carbon monoxide (CO) in the exhaust gas and reduction of nitrogen oxide (NOx) and purify a harmful gas component in the exhaust gas into harmless carbon dioxide (CO.sub.2), water vapor (H.sub.2O), and nitrogen (N.sub.2). A silencer (muffler) 43 configured to reduce exhaust sound is attached downstream of the exhaust purification catalyst 20.

[0025] For the exhaust pipe 18, an exhaust gas recirculation device (hereinafter referred to as an EGR device) 40 is provided, which is configured to recirculate part of the exhaust gas discharged from the engine 10 to the intake manifold 11 of the engine 10. The EGR device 40 has an EGR pipe 41 configured to allow the exhaust pipe 18 and intake manifold 11 of the engine 10 to communicate with each other, and an EGR valve 42 interposed on the EGR pipe 41 and configured to adjust an exhaust gas recirculation rate (EGR flow rate). The opening degree (EGRSTP) of the EGR valve 42 is controlled by an electronic control device 50 to be described later according to the operation state of the engine 10.

[0026] In addition to the airflow meter 14, the LAF sensor 19, the vacuum sensor 30, and the throttle opening degree sensor 31 described above, a cam angle sensor 32 configured to determine the cylinder of the engine 10 is attached in the vicinity of a camshaft of the engine 10. Moreover, a crank angle sensor 33 configured to detect the rotation position of the crankshaft 10a is attached in the vicinity of the crankshaft 10a of the engine 10. A timing rotor 33a having, for example, thirty four (34) protrusions that are arranged at an interval of 10 with two protrusions missing is attached to an end portion of the crankshaft 10a, and the crank angle sensor 33 detects the presence or absence of the protrusion of the timing rotor 33a to detect the rotation position of the crankshaft 10a. As the cam angle sensor 32 and the crank angle sensor 33, electromagnetic pickup sensors or the like may be used, for example.

[0027] These sensors are coupled to the electronic control device 50 (hereinafter referred to as an ECU 50). Further, various sensors such as a water temperature sensor 34 configured to detect the temperature of coolant of the engine 10, an oil temperature sensor 35 configured to detect the temperature of lubricating oil, an accelerator sensor 36 configured to detect the depression amount of an accelerator pedal, that is, the operation amount of the accelerator pedal, and a vehicle speed sensor 37 configured to detect the speed of a vehicle are also coupled to the ECU 50.

[0028] The ECU 50 has a microprocessor configured to perform arithmetic processing, an EEPROM configured to store a program causing the microprocessor to execute processing and the like, a RAM configured to store various data such as an arithmetic processing result, a backup RAM configured to hold the contents of stored data by a battery or the like, an input/output I/F, and the like. Further, the ECU 50 includes an injector driver configured to drive the injector 12, an output circuit configured to output an ignition signal, a motor driver configured to drive an electric motor 13a configured to open and close the electronically controlled throttle valve 13, and the like.

[0029] In the ECU 50, the cylinder is determined from the output of the cam angle sensor 32, and a rotation angular velocity and an engine speed are obtained from the output of the crank angle sensor 33. Moreover, in the ECU 50, based on detection signals received from various sensors described above, various information such as an intake air amount, an intake pipe negative pressure, an accelerator pedal opening degree, the air-fuel ratio of the air-fuel mixture, and a water temperature and an oil temperature in the engine 10 is acquired. Based on various information acquired as described above, the ECU 50 controls a fuel injection amount, an ignition timing, and various devices such as the throttle valve 13 and the EGR valve 42, thereby integrally controlling the engine 10.

[0030] Further, the engine 10 includes the blow-by gas processing device 60 configured to introduce blow-by gas having leaked from the combustion chamber into a crankcase 10b through between the cylinder and a piston into the intake pipe 15 or the like (intake system) and combust the blow-by gas.

[0031] The blow-by gas processing device 60 includes a PCV hose (scavenging line) 61 coupled to the PCV valve cover 65 to be described later and configured to allow the PCV valve cover 65 and the downstream side of the throttle valve 13, such as the intake pipe 15, to communicate with each other to introduce (recirculate) the blow-by gas to the intake pipe 15 or the like, the PCV valve 62 (flow rate control valve) attached to a cylinder block 10c and configured to adjust the flow rate of the blow-by gas flowing through the PCV hose 61 according to the pressure of the intake pipe 15 or the like, and a fresh air hose (fresh air line) 63 configured to allow the upstream side of the throttle valve 13 and the inside of the crankcase 10b to communicate with each other to introduce fresh air.

[0032] It is noted that in the present embodiment, as the PCV valve 62, for example, one differentially operated according to a pressure difference between the crankcase 10b and the downstream side of the throttle valve 13 (for example, the intake manifold 11) is used. In more detail, the PCV valve 62 has, for example, a cylindrical housing, and in the housing, has a valve body slidable in an axial direction and a spring member configured to bias the valve body in a valve closing direction (downward). The valve body has a substantial rod shape, and has a tip end portion (upper end portion) tapered such that the diameter thereof decreases. The tip end portion is inserted into a through hole of a plate provided at the tip end of the valve. The valve body is configured to slide in the axial direction (up-down direction) according to a balance between the negative pressure of the intake pipe and the spring force of the spring member, and by changing a passage cross-sectional area according to the position of the valve body, the flow rate of the blow-by gas passing through the PCV valve 62 is adjusted.

[0033] A hexagonal flange is provided at the outer periphery of the housing of the PCV valve 62, and the outer periphery of the housing on the lower side thereof is threaded so that the housing can be screwed into a screw hole of the cylinder block 10c.

[0034] In one example, the blow-by gas processing device 60 according to the present embodiment can comply with laws and regulations on detachment of the PCV valve 62, and prevents (or reduces) a turbid solution mixed with condensed water or the like generated by condensation of oil contained in the blow-by gas or moisture contained in the blow-by gas from together flowing into the PCV valve 62.

[0035] Thus, the blow-by gas processing device 60 includes the PCV valve cover 65. The PCV valve cover 65 is disposed coaxially with the PCV valve 62, and is attached to the cylinder block 10c so as to cover the entire surface of the PCV valve 62. Thus, it is configured such that the PCV valve 62 is not detachable unless the PCV valve cover 65 is not detached.

[0036] The PCV valve cover 65 and the PCV hose 61 have such inner diameters (cross-sectional areas) that the engine 10 is stopped when the PCV valve cover 65 is detached or the engine 10 is not startable in a state where the PCV valve cover 65 is detached. That is, when the PCV valve cover 65 is detached, air is suctioned through the PCV valve cover 65 and the PCV hose 61 (it is noted that the air is suctioned from the downstream side of the throttle valve 13, and therefore, the airflow meter 14 is not able to detect the amount of such air), and misfire occurs because the air-fuel ratio becomes extremely lean. Thus, the state of the PCV valve cover 65 (the PCV valve 62) being detached can be recognized by a worker or the like, and the compliance with the above-described laws and regulations such as OBD2 can be achieved.

[0037] In order to stop the engine 10 when the PCV valve cover 65 is detached, the inner diameter of the PCV valve cover 65 is set to a relatively-great value (for example, several tens of mm), and for this reason, a gap is formed between the PCV valve 62 and the PCV valve cover 65 and the turbid solution containing the oil, the condensed water, or the like is accumulated therein.

[0038] Thus, in a state where the PCV valve cover 65 is attached to the cylinder block 10c, the inner diameter of the PCV valve cover 65 (the cross-sectional area of the PCV valve cover 65 taken along the horizontal direction) on the tip end side (vertically upper side) with respect to a plane including an end surface of a tip end portion (opening) of the PCV valve 62 is greater than the inner diameter of the PCV valve cover 65 (the cross-sectional area of the PCV valve cover 65 taken along the horizontal direction) on the base end side (vertically lower side) with respect to the plane including the end surface of the tip end portion (opening) of the PCV valve 62. In other words, the PCV valve cover 65 has a base end portion 65a covering the side surface of the PCV valve 62 with a gap therebetween, and a great diameter portion 65b that is provided on the tip end side with respect to the plane including the tip end surface of the PCV valve 62 and that has a greater diameter (increased diameter) than that of the base end portion 65a.

[0039] In some embodiments, the PCV valve cover 65 is configured such that the base end portion (small diameter portion) 65a and the great diameter portion 65b have, for example, cylindrical shapes. It is noted that the PCV valve cover 65 may have a rectangular tubular shape (for example, rectangular tubular shape having a regular hexagonal cross section, or the like). A nipple-shaped joint (attachment) on which the PCV hose 61 is to be fitted protrudes from the top surface (upper end surface) of the PCV valve cover 65 (the great diameter portion 65b).

[0040] The PCV valve cover 65 has, at the outer periphery of the lower end of the base end portion 65a, a flange 65c having a bolt attachment hole (through hole), and is fastened to the cylinder block 10c with a bolt. The PCV valve 62 and the PCV valve cover 65 are attached to the upper surface (top surface) of the cylinder block 10c such that the axial lines of the PCV valve 62 and the PCV valve cover 65 are parallel with the vertical direction.

[0041] In some embodiments, the PCV valve cover 65 is made of metal (for example, aluminum, iron, or the like) having excellent thermal conductivity. It is noted that the PCV valve cover 65 may be made of a material such as resin (engineering plastic). The PCV valve cover 65 may be manufactured, for example, by a casting method using a core, a method in which parts formed separately as the base end portion 65a and the great diameter portion 65b are joined, a hollowing method (a method of forming the great diameter portion 65b) by machining, or the like.

[0042] With the above-described configuration, that is, the configuration in which the PCV valve cover 65 and the PCV hose 61 have such the inner diameters (cross-sectional areas) that the engine 10 is stopped when the PCV valve cover 65 is detached or the engine 10 is not startable in the state where the PCV valve cover 65 is detached. Thus, when the PCV valve cover 65 is detached, air is suctioned through the PCV valve cover 65 and the PCV hose 61, and misfire occurs because the air-fuel ratio becomes extremely lean. Thus, the worker or the like can recognize the state of the PCV valve cover 65 (the PCV valve 62) being detached.

[0043] The PCV valve cover 65 is disposed coaxially with the PCV valve 62, and is attached to the cylinder block 10c so as to cover the entire surface of the PCV valve 62. Thus, as indicated by a broken line in FIG. 2, the turbid solution may be accumulated until reaching the tip end surface of the PCV valve 62. In this state, when (G) is applied after acceleration, the liquid surface tilts as indicated by a solid line in FIG. 2. The inner diameter of the PCV valve cover 65 (the cross-sectional area of the PCV valve cover 65 taken along the horizontal direction) on the tip end side (vertically upper side) with respect to the plane including the end surface of the tip end portion (opening) of the PCV valve 62 is greater than the inner diameter of the PCV valve cover 65 (the cross-sectional area of the PCV valve cover 65 taken along the horizontal direction) on the base end side (vertically lower side) with respect to such a plane. Thus, during acceleration, deceleration, or turning of the vehicle, when the liquid surface of the turbid solution tilts as indicated by the solid line in FIG. 2 due to longitudinal acceleration (longitudinal G) or lateral acceleration (lateral G), part (turbid solution at the upper surface) of the turbid solution (liquid surface) flows into the great diameter portion 65b, and therefore, the liquid surface of the turbid solution lowers and the inflow of the turbid solution into the PCV valve 62 is prevented (or reduced).

[0044] As described in detail above, according to the present embodiment, when the PCV valve cover 65 is detached, air is suctioned through the PCV valve cover 65 and the PCV hose 61, and misfire occurs because the air-fuel ratio becomes extremely lean. Thus, the state of the PCV valve cover 65 (the PCV valve 62) being detached can be recognized by the worker or the like, and the compliance with the laws and regulations such as OBD2 can be achieved. Moreover, during the acceleration, deceleration, or turning of the vehicle, when the liquid surface of the turbid solution tilts due to the longitudinal acceleration (longitudinal G) or the lateral acceleration (lateral G), part (turbid solution at the upper surface) of the turbid solution (liquid surface) flows into the great diameter portion 65b, and therefore, the liquid surface of the turbid solution lowers and the inflow of the turbid solution into the PCV valve 62 can be prevented (or reduced).

[0045] As a result, the compliance with the laws and the regulations on the detachment of the PCV valve 62 can be achieved, and the inflow of the turbid solution mixed with the condensed water or the like generated by the condensation of the oil contained in the blow-by gas or the moisture contained in the blow-by gas into the PCV valve 62 can be prevented (or reduced).

[0046] According to the present embodiment, each of the base end portion (small diameter portion) 65a and great diameter portion 65b of the PCV valve cover 65 has the cylindrical shape (or the rectangular tubular shape), and each of the PCV valve 62 and the PCV valve cover 65 is attached to the upper surface (top surface) of the cylinder block 10c such that the axial line thereof is parallel with the vertical direction. Thus, the acceleration (longitudinal acceleration (longitudinal G) and lateral acceleration (lateral G)) in all directions can be handled, that is, the inflow of the turbid solution can be properly prevented.

Second Embodiment

[0047] The PCV valve cover 65 according to the first embodiment described above has the base end portion 65a and the great diameter portion 65b having the different inner diameters, and for this reason, in manufacturing thereof, for example, the core is to be used in the casting, the two parts are to be used as the base end portion 65a and the great diameter portion 65b, or the hollowing (the formation of the great diameter portion 65b) by machining is to be performed. This tends to increase the number of manufacturing steps and a manufacturing cost. Normally, tendency shows that among acceleration G, deceleration G, and turning G (lateral G), the deceleration G is the greatest. That is, the amount of turbid solution flowing into the PCV valve 62 during the deceleration tends to be great (the amount of the inflowing turbid solution tends to be increased).

[0048] For these reasons, in order to more easily manufacture the PCV valve cover 65 as compared with the first embodiment described above, the shape (configuration) may be employed, in which the volumetric capacity on the front side (deceleration G direction) of the vehicle is increased and no undercut is provided.

[0049] Next, a blow-by gas processing device 60D according to a second embodiment will be described with reference to FIG. 3. FIG. 3 is a cross-sectional view illustrating the configuration of a main portion (the PCV valve 62, a PCV valve cover 65D, and the like) of the blow-by gas processing device 60D. It is noted that the same elements as those of the first embodiment or elements similar to those of the first embodiment are denoted by the same reference numerals in FIG. 3.

[0050] The PCV valve cover 65D has a tubular shape (for example, cylindrical shape, rectangular tubular shape, or the like), and is attached to the cylinder block 10c so as to cover the entire surface of the PCV valve 62. In some embodiments, the PCV valve cover 65D has a circular cross section (cross section taken along the horizontal direction). It is noted that the PCV valve cover 65D may have an ellipsoidal cross section, an oval cross section, an egg-shaped cross section, or the like (cross section taken along the horizontal direction).

[0051] In one example, the PCV valve cover 65D is attached with the center axis thereof shifted to the front side (deceleration G direction) of the vehicle with respect to the center axis of the PCV valve 62 (see a dash-dotted line in FIG. 3). Thus, the volumetric capacity on the front side of the vehicle is greater than the volumetric capacity on the rear side of the vehicle.

[0052] It is noted that the other configurations are the same as or similar to those of the above-described PCV valve cover 65 (first embodiment), and therefore, detailed description thereof will be omitted.

[0053] According to the present embodiment, the formation of the great diameter portion 65b is not necessary, and therefore, the number of manufacturing steps and the manufacturing cost can be reduced. The PCV valve cover 65D is configured such that the center axis thereof is shifted to the front side (deceleration G side) of the vehicle with respect to the center axis of the PCV valve 62, and therefore, the volumetric capacity (volume) on the front side of the vehicle is greater than the volumetric capacity (volume) on the rear side of the vehicle. Thus, as indicated by a solid line in FIG. 3, when the turbid solution moves toward the front side of the vehicle (the liquid surface of the turbid solution tilts) during the deceleration of the vehicle, the liquid surface of the turbid solution lowers, and therefore, the inflow of the turbid solution into the PCV valve 62 due to the deceleration G can be prevented (or reduced).

[0054] It is noted that the acceleration G and the turning G (lateral G) are relatively smaller than the deceleration G, and therefore, the tilt of the liquid surface is smaller and the amount of the inflowing turbid solution is smaller. Thus, the inflow of the turbid solution can fall within an acceptable range.

[0055] The embodiments of the disclosure have been described above, but are not limited to the embodiments above and various modifications can be made. For example, in the embodiments above, the case where the embodiment of the disclosure is applied to the natural aspiration (NA) engine has been described as an example, but the embodiment of the disclosure can also be applied to an engine including a supercharger (turbocharger or the like).

[0056] In the embodiments above, the gasoline engine using gasoline as the fuel has been described as an example, but the embodiment of the disclosure can also be applied to, for example, a hydrogen engine using hydrogen as fuel, a diesel engine using light oil as fuel, and the like.

[0057] In the embodiments above, the case where the embodiment of the disclosure is applied to the typical gasoline engine has been described as an example, but the embodiment of the disclosure can also be applied to, for example, an engine of a hybrid vehicle (HEV) including the engine and an electric motor as a driving force source, or the like.

[0058] According to the blow-by gas processing device according to one aspect of the disclosure, the PCV valve cover is disposed coaxially with the PCV valve and is attached to the cylinder block so as to cover the PCV valve, and the inner diameter of the PCV valve cover on the tip end side with respect to the plane including the tip end surface of the PCV valve is greater than that of the PCV valve cover on the base end side with respect to such a plane. Thus, during the acceleration, deceleration, or turning of the vehicle, when the liquid surface of the turbid solution tilts due to the longitudinal acceleration (longitudinal G) or the lateral acceleration (lateral G), part (turbid solution at the upper surface) of the turbid solution (liquid surface) flows into the great diameter portion, and therefore, the liquid surface of the turbid solution lowers and the inflow of the turbid solution into the PCV valve can be prevented (or reduced).

[0059] According to the embodiment of the disclosure, the compliance with the laws and the regulations on the detachment of the PCV valve can be achieved, and the inflow of the turbid solution mixed with the condensed water or the like generated by the condensation of the oil contained in the blow-by gas or the moisture contained in the blow-by gas into the PCV valve can be prevented (or reduced).