JPH041172B2 - - Google Patents

Description

Detailed Description of the Invention "Industrial Application Field" The present invention is an internal combustion engine with a supercharger, in which air compressed by a supercharger is introduced into a cylinder head via a charge air cooler, or the air is This invention relates to an air supply switching device that switches a flow path to directly supply air to a cylinder head.

"Prior Art" A supercharged internal combustion engine supplies air compressed by a supercharger into the cylinder to increase combustion efficiency and increase engine output. Because the density of air does not increase as the temperature of the air increases and thermally expands, a charge air cooler is installed after the supercharger to cool the air, and the air compressed by the supercharger is cooled. Generally, it is cooled in a container and then introduced into a cylinder head.

However, installing a charge air cooler as described above improves combustion efficiency when the engine is operating at high load, but it improves combustion efficiency when the engine is operating at low load, especially when operating with low-quality oil. The problem is that the air is supercooled by the charge air cooler, and the moisture in it condenses and reacts with the sulfur content in the cylinder, causing sulfuric acid corrosion on the piston, cylinder liner, cylinder head, etc. be.

To prevent this sulfuric acid corrosion, for example,
As shown in the figure, piping 2 on the inlet side of the supply air cooler 1
A pressure detection tube 3 is provided for detecting the pressure inside the pipe 2, and a pressure detection plate 4 is installed in the pressure detection tube 3.
A pressure detection device 7 consisting of a detection shaft 5 and a spring 6 is provided, and an on-off valve 9 for opening and closing the bypass passage 8 of the supply air cooler 1 is provided at the end of the detection shaft 5 passing through the bottom of the pressure detection tube 3. An air supply switching device is known that is provided with an on-off valve operating device 10 that rotates the valve around its axis (Japanese Utility Model Publication No. 60-3941). This air supply switching device is
When the pressure in the pipe 2 on the inlet side of the supply air cooler 1 is low, the pressure detection plate 4 in the pressure detection tube 3 moves to the right in FIG. An on-off valve actuating device 10 connected via an on-off valve 5 opens an on-off valve 9 to direct the air sent from the supercharger through the bypass path 8 without passing through the air cooling section 1a of the charge air cooler 1. It is passed through and supplied to the cylinder head.

"Problems to be Solved by the Invention" However, in the conventional supply air switching device described above, the pressure detection tube 3 is provided in the piping 2 on the inlet side of the supply air cooler 1, and the pressure detection device 7 is opened/closed. Since the valve 9 and the on-off valve operating device 10 must be provided, there are problems in that the structure becomes complicated, the device becomes large, and the response speed is slow. In particular, since the on-off valve actuating device 10 must be installed outside the air supply system piping, there are restrictions on the installation location and there are complaints that it is difficult to install.

The present invention was made in view of the above circumstances, and
The object thereof is to provide an air supply switching device for a supercharged internal combustion engine that has a simple structure and can be easily installed in air supply system piping.

"Means for Solving the Problems" In order to achieve the above object, the present invention switches the flow path to the charge air cooler side or the cylinder head side at the branch part of the pipe line on the outlet side of the supercharger. A cylindrical member is rotatably provided, and the cylindrical member is provided with a detection blade that rotates the cylindrical member according to the flow velocity of air in the pipe, and a support portion that supports the cylindrical member. A rotation suppressing member for suppressing rotation of the cylindrical member is provided between the cylindrical member and the cylindrical member.

"Operation" In the air supply switching device of the present invention, the cylindrical member rotates based on the rotational force that the detection blade receives due to the flow velocity of the air in the pipe and the suppressing force of the rotation suppressing member. Then, the flow path through which the air compressed by the supercharger flows is switched to the charge air cooler side or the cylinder head side.

"Embodiment" Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 4.

In the figure, 20 is a supercharger, and an exhaust pipe 21 is connected to a turbine case of this supercharger 20, and an air supply pipe 22 is connected to a blower case.
A low-load pipe 23 that communicates directly with the cylinder head and a high-load pipe 24 that communicates with the cylinder head via an air supply cooler are connected to the air supply pipe 22, respectively. Above air supply piping 2
2. An air supply switching device 26 according to the present invention is installed at a branch portion 25 consisting of the low-load pipe 23 and the high-load pipe 24. In this air supply switching device 26, the cylindrical member 27 is connected to the
The cylindrical member 27 is rotatably attached to the inner wall of the branch portion 25, and includes an outer cylindrical portion 27a and a central shaft portion 27b disposed at the center of the outer cylindrical portion 27a.
and a connecting portion 27c that connects the outer cylinder portion 27a and the central shaft portion 27b at their outlet ends. The cylindrical member 27 has an inlet formed into an annular shape between the outer cylindrical portion 27a and the central shaft portion 27b, and an outlet formed between the outer cylindrical portion 27a, the central shaft portion 27b, and the connecting portion 2.
7c are each formed in a half-moon shape, and as the surface of the connecting portion 27c on the air supply pipe 22 side goes from the central shaft portion 27b toward the outer cylinder portion 27a,
The cylindrical member 27 has a tapered surface 27d that slopes smoothly toward the inlet side A. Further, the cylindrical member 2
A spring chamber 30 is formed inside the end of the outlet side B of the tube 7 and the partition wall portion (supporting portion) 29 of the low-load pipe 23 and high-load pipe 24. A helical spring (rotation suppressing member) 31 is housed inside, with one end secured to the cylindrical member 27 and the other end secured to the partition wall portion 29.

Three detection blades 32 are provided between the outer cylinder part 27a and the central shaft part 27b on the entrance side A of the cylindrical member 27.
are arranged at approximately equal intervals in a plane perpendicular to the center shaft portion 27b, and are supported rotatably around their respective axes, and the support shaft of each detection blade 32 on the center shaft portion 27b side 33 is provided to protrude into a switching adjustment chamber 34 formed inside the central shaft portion 27b. A triangular cam 35 is disposed at the end of each support shaft 33, with one corner thereof connected to the end and perpendicular to the axis of each support shaft 33. These cams 35 are respectively held between two sliding plates 36 and 37 that slide inside the switching adjustment chamber 34 in the axial direction of the cylindrical member 27. Further, a first spring 38 is disposed between the one sliding plate 36 and one end surface of the switching adjustment chamber 34 (the end surface on the partition wall 29 side).
However, a second spring 39 is installed between the other sliding plate 37 and the other end surface of the switching adjustment chamber 34 (the end surface on the air supply pipe 22 side). and,
Support rod 40 fixed to the other sliding plate 37
is provided to protrude from the tip of the central shaft portion 27b, and a support ring 42 is attached to the tip of the support rod 40 by a retaining ring 41. Further, between the support ring 42 and the tip of the central shaft portion 27b, around the support rod 40,
A transformation spring 43 made of a shape memory alloy is attached, which increases the spring force when the temperature exceeds a set temperature (transformation point). When the flow velocity of the fluid flowing in the air supply pipe 22 is low (during low load operation), each detection blade 32 detects the flow of the fluid in a state where the spring forces of the springs 38 and 39 are balanced. When the flow rate of the fluid is high (during high-load operation), the fluid hitting each of the tilted detection blades 32 causes the transformation spring 43 to be tilted at a predetermined angle. When the transformation point is exceeded, the increased spring force of the transformation spring 43 causes each of the sliding plates 36 and 37 to slide toward the air supply pipe 22 side (supercharger 20 side), and the above-mentioned detections are performed. The state of connection between each of the detection blades 32 and the cam 35 is set such that the blades 32 are parallel to the fluid flow direction.

Further, a protrusion 44 is fixed at an appropriate position on the outer circumference of the cylindrical member 27, and a protrusion 44 is fixed to the outer circumference of the cylindrical member 27.
A first stopper 4 is provided at a position facing the protrusion 44 to align the half-moon-shaped outlet of the cylindrical member 27 with the low-load pipe 23 during low-load operation.
5 is disposed, and when the rotational force generated in each detection blade 32 by the fluid overcomes the rotational force of the helical spring 31 and the cylindrical member 27 rotates during high-load operation, the cylindrical member 27 rotates. shaped member 2
A second stopper 46 is provided to align the half-moon-shaped outlet of No. 7 with the high-load pipe 24.

In the air supply system provided with the supply air switching device 26 configured as described above, during low load operation (for example,
35% or less load), each spring 38, which is housed in the switching adjustment chamber 34 inside the central shaft portion 27b,
By the spring force of 39, each cam 35 is moved to each sliding plate 3.
6 and 37 and connected to each cam 35 maintains a predetermined inclination angle with respect to the flow direction of the fluid flowing in the pipe, but since the flow velocity of the fluid is low, The rotational force generated in the detection blade 32 is small. As a result, each of the above detection blades 3
Since the rotational force of the helical spring 31 in the spring chamber 30 is greater than the rotational force caused by the cylindrical member 27
stands still with its protrusion 44 pressed against the first stopper 45, whereby the half-moon-shaped outlet of the cylindrical member 27 communicates with the low-load pipe 23. Therefore, the air compressed by the supercharger 20 is transferred to the air supply pipe 2
2, through the inside of the cylindrical member 27, and directly to the cylinder head side via the low-load piping 23, the air is prevented from being supercooled by the charge air cooler, and the air inside the cylinder is The production of sulfuric acid due to coagulated moisture and sulfur content is suppressed, and sulfuric acid corrosion does not occur on pistons and the like.

Also, during medium load operation (e.g. 35% to 60% load)
In this case, since the velocity of the flow inside the pipe increases, the rotational force generated in each of the detection blades 32 inclined at the predetermined angle increases, overcoming the rotational force of the helical spring 31 in the spring chamber 30, and The cylindrical member 27 rotates. As a result, the cylindrical member 27
The half-moon-shaped outlet communicates with the high-load piping 24, and the air compressed by the supercharger 20 passes from the air supply piping 22 through the inside of the cylindrical member 27, and is supplied via the high-load piping 24. The air is sent to the cooler. Further, when the flow velocity inside the pipe increases and the cylindrical member 27 rotates until its protrusion 44 contacts the second stopper 46, the low-load pipe 23 is closed by the connecting portion 27c, and the cylindrical member 27 A half-moon-shaped outlet communicates with high-load piping 24 . Therefore, the air compressed by the supercharger 20 is transferred to the air supply pipe 22 and the cylindrical member 27.
and is sent to the supply air cooler side via the high-load piping 24. As a result, since the air compressed and heated by the supercharger 20 is cooled by the charge air cooler, the combustion efficiency within the cylinder is increased and the output of the engine is increased.

Furthermore, when the fluid on the inlet side A of the cylindrical member 27 becomes hotter than the set temperature of the transformation spring 43 (during high load operation, e.g. 60% to 100% load), the transformation spring 43 transforms and its Since the spring force increases, the transformation spring 43 overcomes the spring force of the second spring 39, and in FIG.
2 and the support rod 40 are moved upward (toward the supercharger 20 side). Therefore, the sliding plate 37 connected to the support rod 40 slides upward in the switching adjustment chamber 34, and along with this, the sliding plate 36 is moved upward by the spring force of the first spring 38. Since the lower corner of the cam 35 is pushed up, the cam 35 rotates counterclockwise around the support shaft 33, and each detection blade 32 connected to the support shaft 33 rotates counterclockwise to prevent the fluid from flowing. is almost parallel to the flow direction, and the resistance and flow loss due to each detection blade 32 are suppressed to a minimum.

As described above, in the above-described air supply switching device 26, when the flow velocity of the fluid at the inlet side A of the cylindrical member 27 is small (during low load operation), the helical spring 31 allows the air supply pipe 22 to and low load piping 23
The air compressed by the supercharger 20 is guided directly into the cylinder to prevent the charge air from being supercooled by the charge air cooler. Further, the inlet side A of the cylindrical member 27
When the flow velocity of the fluid increases to a certain extent (at medium load operation or higher), the rotational force generated by the detection blade 32 overcomes the rotational force by the helical spring 31, and the air supply piping 22 and the high-load piping 24 are connected to each other. The air compressed by the supercharger 20 is cooled by the charge air cooler and then supplied into the cylinder.
Combustion efficiency within the cylinder improves, increasing engine output. Furthermore, as the temperature of the fluid increases,
When the transformation point of the transformation spring 43 is exceeded (when operating under high load), the spring force of the transformation spring 43 becomes the second
Overcoming the spring force of the spring 39, the detection blades 32 are rotated together with the cam 35 so that they are nearly parallel to the direction of fluid flow, so each detection blade 3
2. Minimize resistance and flow loss.

"Effects of the Invention" As explained above, the present invention has a rotatable cylindrical member that switches the flow path to the charge air cooler side or the cylinder head side at the branch part of the pipe line on the outlet side of the supercharger. and providing the cylindrical member with a detection blade that rotates the cylindrical member according to the flow velocity of air in the pipe, and between the cylindrical member and a support portion that supports the cylindrical member. is provided with a rotation suppressing member that suppresses the rotation of the cylindrical member, so that the rotational force applied to the detection blade due to the flow velocity of the air in the pipe and the suppressing force of the rotation suppressing member are used. When the air flow velocity is low, the suppressing force overcomes the rotational force and directs the flow path toward the cylinder head, and when the air flow velocity increases, the rotational force overcomes the suppression force and directs the flow path toward the cylinder head. By switching to the air cooler side, it is possible to prevent supercooling of the charge air by the charge air cooler during low load operation, and to reduce combustion by cooling the supercharged air during high load operation. In addition to being able to improve efficiency and increase engine output, it has the excellent effects of being simple and compact in structure, and being easily incorporated into air supply piping.

[Brief explanation of drawings]

1 to 4 show one embodiment of the present invention, in which FIG. 1 is a schematic configuration diagram of an air supply piping system, and FIG.
The figure is a front view of the supply air switching device, Figure 3 is a sectional view of the same,
FIG. 4 is a sectional view of the central shaft portion, and FIG. 5 is a sectional view showing a conventional air supply switching device. 20...Supercharger, 22...Air supply piping, 23...
Low load piping, 24...High load piping, 25...
Branch portion, 26... Air supply switching device, 27... Cylindrical member, 29... Partition wall part (support part), 31... Spiral spring (rotation suppressing member), 32... Detection blade.

Claims (1)

[Claims] 1. In a charge air switching device for a supercharged internal combustion engine that switches the flow path in order to introduce air that has passed through a supercharger to the cylinder head via a charge air cooler or to supply the air directly to the cylinder head. A cylindrical member for switching the flow path to the charge air cooler side or the cylinder head side is rotatably provided at a branching part of the pipe line on the outlet side of the supercharger, and a pipe line is connected to the cylindrical member. A detection blade that rotates the cylindrical member according to the flow velocity of the air inside the cylindrical member is provided, and a detection blade that detects the rotation of the cylindrical member is provided between the support portion that supports the cylindrical member and the cylindrical member. An air supply switching device for an internal combustion engine with a supercharger, characterized in that a rotation suppression member is provided.