JPH051815U - Blow-by gas recirculation device - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent oil from flowing into the blow-by gas passage, improve the manufacturability by improving the compactness, weight reduction, and assemblability, and improve the machining accuracy. [Structure] An inner head cover 17 is provided inside a cylinder head cover 6 which covers the upper part of the cylinder head 4 to form a blow-by gas passage 18, and the inner head cover 17 is provided.
The edge portion is bent to form the flange portion 17a. Then, a weir 19 for preventing oil inflow is provided in the outlet hole portion 3a of the blow-by gas passage 3 of the cylinder head 4, and the weir 19 and the flange portion 17a are connected. As a result, the blow-by gas passage 3 is separated from the oil sump 9 and the like, so that oil does not enter the blow-by gas passage 3 from the cam shaft lubricating oil sump 9 and the like. Further, since the weir 19 is only provided in the outlet hole 3a of the blow-by gas passage 3, the size, weight and assembly are improved, the manufacturability is improved, and the processing accuracy is improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a blow-by gas recirculation device applicable to a 4-cycle engine.

[0002]

[Prior Art]

 The so-called blow-by gas, which leaked from the combustion chamber of the engine through the gap between the piston ring and the cylinder wall into the crankcase, contained a large amount of unburned hydrocarbons with strongly acidic water. Then it cannot be released into the atmosphere. Therefore, conventionally, an engine of a vehicle or the like is provided with a blowby gas recirculation device that recirculates the blowby gas from the crankcase to the intake passage of the engine and guides it again to the combustion chamber for combustion.

The flow of blow-by gas by this blow-by gas recirculation device will be described below with reference to FIG. The blow-by gas is guided from the crank chamber 1 to the cam chamber 5 of the cylinder head 4 through the blow-by gas passage 3 such as the cylinder block 2 as shown by the arrow A, and from the cam chamber 5 to the cylinder head cover 6. Then, it is guided from the cylinder head cover 6 to the intake passage such as the intake manifold 8 via the air cleaner 7 or directly to the intake passage such as the intake manifold 8 without the air cleaner 7. Further, the blow-by gas is guided from the intake passage to the combustion chamber (not shown) and re-combusted.

The blow-by gas passage 3 of the blow-by gas recirculation device is formed in a part of the wall portion of the cylinder block 2 and the cylinder head 4, and the upper opening of the blow-by gas passage 3, that is, the blow-by gas passage. The outlet hole portion 3a of 3 is open to the cam chamber 5 of the cylinder head 4. Therefore, the blow-by gas is guided to the upper cylinder head cover 6 through the cam chamber 5.

However, since the outlet hole 3a of the blow-by gas passage 3 is open to the cam chamber 5 of the cylinder head 4, oil flows from the cam shaft lubricating oil reservoir 9 into the blow-by gas passage 3 or the rocker The blow-by gas passage 3 is blocked by the inflow of the oil that flows out to lubricate the rocker arm 11 from the shaft 10 into the blow-by gas passage 3, and the blow-by gas stays in the crank chamber 1 for complete degassing. There was no problem. Therefore, as shown in FIG. 4, a weir 12 for preventing oil from flowing into the blow-by gas passage 3 is provided in the outlet hole portion 3a of the blow-by gas passage 3 to avoid the above-mentioned problems.

The other passage (passage on the left side in FIGS. 3 and 4) provided in the cylinder block 2 flows down from the cam chamber 5 to an oil pan (not shown) (indicated by an arrow B). The oil return passage 13 for lubricating oil is provided. In the figure, reference numeral 14 is a weir 14 of an oil reservoir 9 for lubricating the camshaft, which is provided in an opening of the oil return passage 13 on the cam chamber 5 side. Reference numeral 15 is a cam shaft for opening and closing the intake valve and exhaust valve, and reference numeral 16 is a blow-by pipe.

As a blow-by gas recirculation device for an engine, there is one disclosed in Japanese Utility Model Laid-Open No. 57-171111. What is disclosed in this publication is that the upper end of the blow-by gas passage for blow-by gas is provided at a position higher than the upper end of the oil return hole in the valve operating chamber.

Further, as a breather device for an internal combustion engine, there is one disclosed in Japanese Utility Model Laid-Open No. 57-148007. What is disclosed in this publication is that an oil return hole is formed by providing a partition in the blow-by gas passage leading from the cylinder head to the cylinder block, and the oil return hole is used to prevent the oil from blocking the blow-by gas passage. Is returned to the crank chamber.

Further, as a blow-by gas recirculation device, there is one disclosed in Japanese Utility Model Laid-Open No. 59-196509. In the device disclosed in this publication, an extension pipe that connects to the blowby gas passage is integrally attached to the cylinder head cover, and the tip of this extension pipe is pressed into the blowby gas passage when the cylinder head cover is attached to the blowby gas passage. This is to prevent oil from flowing into the gas passage.

[0010]

[Problems to be solved by the device]

 In the conventional technology described above, a weir is provided at the exit hole of the blow-by gas passage to prevent oil from flowing into the blow-by gas passage.However, this weir alone provides an oil reservoir for camshaft lubrication to the blow-by gas passage. It was not possible to prevent oil from flowing in from the rocker shaft or oil from the rocker shaft. If the oil flows into the blow-by gas passage as described above, the blow-by gas passage is closed as in the above case, which causes a problem that the crank chamber is not sufficiently degassed. Therefore, a blow-by gas passage through which oil does not flow is needed and desired.

[0011] The one disclosed in Japanese Utility Model Laid-Open No. 57-171111 has a problem that the inflow of oil cannot be completely blocked because only the upper end of the blow-by gas is made higher than the oil return hole. The one disclosed in Japanese Utility Model Laid-Open No. 57-148007 has a partition for preventing the inflow of oil in the narrow portion of the blow-by gas passage, so the space for forming this partition and the partition are installed. As a result, the number of parts increases, and there are problems in terms of size, weight reduction, and assembly. Further, in the one disclosed in Japanese Utility Model Laid-Open No. 59-196509, the tip of the extension pipe attached to the cylinder head cover is pressed into the blow-by gas passage when the cylinder head cover is attached to the cylinder head. Therefore, if the press-fitted state becomes loose, oil may flow into the blow-by gas passage and block the passage. If you want to maintain the press-fitted state, the dimensional accuracy of the dimension up to the joint surface between the cylinder head and the cylinder head cover and the dimension up to the tip of the extension pipe, and the diameter of the press-fitted portion of the extension pipe and the diameter of the blowby gas passage are Fitting accuracy is required and there is a problem in manufacturing.

The present invention has been made to solve the above-mentioned conventional problems, and improves the opening of the blow-by gas passage inside the cylinder head to prevent oil from flowing into the blow-by gas passage and to reduce the size. It is an object of the present invention to provide a blow-by gas recirculation device which is lighter in weight, has better assembling property, and has improved processing accuracy.

[0013]

[Means for Solving the Problems]

 As a means for solving the above problems, the present invention provides a blow-by gas passage by providing an inner head cover inside a cylinder head cover that covers the upper part of a cylinder head, and bends an edge portion of the inner head cover to form a flange portion. And a weir for preventing oil inflow is provided in the outlet hole portion of the blow-by gas passage of the cylinder head, and the weir and the flange portion are connected to each other.

[0014]

[Action]

 According to the present invention, since the weir that connects to the flange portion of the inner head cover is provided in the outlet hole of the blow-by gas passage and the blow-by gas passage and the oil sump are completely separated, the blow-by gas passage is camshaft lubricated. Oil will not enter from the oil sump for the machine or from the rocker shaft. In addition, the structure of the blow-by gas passage is simplified because only a weir is provided at the outlet hole of the blow-by gas passage.

[0015]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The same members as those in FIGS. 3 and 4 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, an inner head cover 17 is provided inside a cylinder head cover 6 which covers the upper part of the cylinder head 4, and an upper blow-by gas passage 18 which is a blow-by gas passage is formed. On the other hand, a weir 19 is provided at the cylinder head 4 side outlet hole 3a of the blow-by gas passage 3 provided in the cylinder head 4. The weir 19 is extended upward to the bent flange portion 17a of the inner head cover 17 and is connected to the flange portion 14a in an overlapping manner.

As described above, since the weir 19 provided in the outlet hole 3a on the cylinder head 4 side of the blow-by gas passage 3 and the flange 17a formed at the edge of the inner head cover 17 are overlapped and connected, the weir 19 is connected to the weir 19. Has no openings for oil to flow in. That is, since the blow-by gas passage 3 is completely separated from the oil reservoir 9 and the oil scattering region by the weir, oil flows into the blow-by gas passage 3 from the camshaft lubricating oil reservoir 9 and the rocker shaft 10 The oil does not flow in due to the scattering of the oil that flows out to lubricate the rocker arm 11.

[0017]

[Effect of the device]

 According to the present invention, since the blow-by gas passage and the oil sump are completely separated by providing the weir that is connected to the flange portion of the inner head cover at the outlet hole portion of the blow-by gas passage, the blow-by gas passage is provided with the camshaft. Oil will not enter from the lubricating oil sump or from the rocker shaft. Since the oil no longer penetrates in this way, the blow-by gas passage is not blocked by the oil and the gas is completely degassed and the blow-by gas is completely reburned. In addition, since only a weir is provided in the outlet hole of the blow-by gas passage, the size, weight, and assemblability are improved, which improves manufacturability and improves machining accuracy.

[Brief description of drawings]

FIG. 1 is a plan view of a cylinder head of an engine showing an embodiment of the present invention.

FIG. 2 is a schematic view showing in cross section a part of a cylinder head and a cylinder head cover that covers the cylinder head.

FIG. 3 is a schematic view showing a cross section of a conventional cylinder head portion.

FIG. 4 is a schematic view of a conventional cylinder head portion viewed from above.

[Explanation of symbols]

 3 Blow-by gas passage 3a Outlet hole 4 Cylinder head 6 Cylinder head cover 17 Inner head cover 17a Flange 18 Upper blow-by gas passage 19 Weir

Claims (1)

Claims for utility model registration: 1. An inner head cover is provided inside a cylinder head cover to cover the upper part of the cylinder head to form a blow-by gas passage, and an edge portion of the inner head cover is bent to form a flange portion. A blow-by gas recirculation apparatus, wherein a weir for preventing oil inflow is provided in an outlet hole portion of a blow-by gas passage of the cylinder head, and the weir and the flange portion are connected to each other.