JPH0343382Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention relates to an intake system for a turbocharged engine, and in particular, an air intake system is installed in parallel with an intercooler to increase the pressure in the inlet manifold when the engine rotates at low speed. This invention relates to an improved bypass passage.

[Technical background of the invention] In general, the intake system of an engine with a turbocharger has an intercooler installed in the passage connecting the turbocharger and the inlet manifold to increase charging efficiency, and pressurizes the engine with the turbocharger. The air is cooled by this intercooler and then guided to the inlet manifold.

By the way, when the engine speed is low, the boost pressure is low and the pressure in the inlet manifold does not increase. Therefore, even if an attempt is made to quickly increase the boost pressure during sudden acceleration, the presence of the intercooler will increase ventilation resistance, and the increased volume will require a large amount of air, which will take a long time. Therefore, in the past, in order to increase the boost pressure when the engine rotates at low speeds, a bypass passage was installed in parallel with the intercooler, and a switching valve was installed at the branch point of the bypass passage to open and close depending on the supply pressure (Utility Model No. 50-66011). A bypass passage is provided on the upstream side of the intercooler, and two valves are provided in the bypass passage and the downstream passage of the intercooler that open and close in reverse depending on the supply pressure. (Utility Model Application Publication No. 57-134323) has been announced.

Both of these lead boost pressure from the turbocharger directly to the inlet manifold via the bypass passage when boost pressure is low, improving accelerator response in the low speed rotation range.

[Problems with Background Art] However, the above-mentioned conventional technology has the following drawbacks.

(1) Since the direct valve is actuated by the gradually increasing supply pressure, its opening and closing, that is, passage switching, is gradual, and the bypass passage and intercooler passage may open at the same time, causing the internal pressure of the inlet manifold to decrease. cannot be increased rapidly.

(2) When installing an air-cooled intercooler in a turbocharged engine, long piping is required because the intercooler can only be installed in a location with excellent ventilation. For this reason, in the low speed rotation range where boost pressure is low, unless the pressure in the long pipe is increased, the pressure in the inlet manifold will not rise and the accelerator response will deteriorate. In this respect, in the conventional system, when opening the bypass passage, only one of the entrances and exits of the intercooler passage is closed, and the other remains in communication with the bypass passage. Therefore, in order to increase the boost pressure, it is necessary not only to increase the pressure in the long piping of the intercooler passage, but also to increase the pressure inside the intercooler, resulting in poor responsiveness.

In this way, with conventional systems, it was not possible to rapidly increase the pressure inside the inlet manifold, so the volume of the intercooler was reduced, or the intercooler was installed in a location that did not have very good air permeability. We had no choice but to take measures to shorten the time, sacrificing some performance.

[Purpose of the invention] This invention was made in view of the above circumstances.
The purpose is to obtain an intake system for a turbocharged engine that can rapidly increase the pressure in the inlet manifold in the low speed rotation range of the engine, and that can achieve this with a simple structure. .

[Summary of the invention] In order to achieve the above object, this invention has a main passage leading from the turbocharger to the inlet manifold via the intercooler, and an upstream and downstream side of the intercooler of this main passage. A bypass passage connecting the turbocharger to the direct inlet manifold, which is formed by drawing each other together and connecting the overlapping parts, and communicating the overlapping parts with each other, and a communication point between the bypass passage and the main passage. By closing the communication point, supercharge air is supplied from the turbocharger to the inlet manifold via the intercooler, and by opening the communication point, the supply of supercharge air to the intercooler is cut off. an on-off valve that supplies supercharging air directly from the turbocharger to the inlet manifold; a pressure detection means for detecting the pressure inside the inlet manifold; The present invention is characterized by comprising a valve operating means that closes the on-off valve when the pressure is exceeded and opens the on-off valve when the pressure is lower than a predetermined pressure. This allows the on-off valve to open and close instantly rather than gradually, and when closing the main passage, it closes both the entrance and exit, rather than just one opening, completely cutting off communication with the bypass passage and minimizing the passage volume. This prevents deterioration of accelerator response due to a temporary increase in the number of supercharging air passages in the low engine speed range.

[Embodiment of the invention] Hereinafter, a preferred embodiment of the intake system for a turbocharged engine according to the invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing an embodiment of this invention. In the figure, reference numeral 1 denotes an engine, and the engine 1 is provided with a main passage 6 leading from a turbo supercharger 3 provided in an outlet manifold 2 to an inlet manifold 5 via an intercooler 4. The main passage 6 communicates with the upstream side and the downstream side of the intercooler 4 at one point so that at least one side is drawn into the other side. Due to this communication, a bypass passage 7 directly leading from the turbocharger 3 to the inlet manifold 5 is formed overlapping the main passage 6.

An on-off valve 9 is provided at a communication point 8 between the bypass passage 7 and the main passage 6, and the on-off valve 9 is normally operated so that only the bypass passage 7 is open, and when the intake pressure exceeds a predetermined pressure, this on-off valve 9 is operated. The on-off valve 6 is closed by the valve operating means 11 that responds to the signal of the pressure detection means 10 that detects and issues a signal, and during this time the supercharged air from the turbocharger 3 is not allowed to flow to the bypass passage 7. It is designed to flow into the main passage 6.

As shown in FIG. 2, the communication point 8 is formed by bringing the upstream and downstream sides of the main passage 6 into contact with each other such that their flows are in opposite directions. The on-off valve 9 is rotatably supported at the center of this communication point 8, and an arm 12 is integrally connected to this pivot point at a predetermined angle. That is, as shown in FIG. 2, by rotating the arm 12 clockwise to close the communication point 8, supercharging air is supplied to the inlet manifold 5 via the intercooler 4, and the third
As shown in the figure, by rotating the arm 12 counterclockwise to open the communication point 8, the supply of supercharged air to the intercooler 4 is cut off and the supercharged air is directly supplied to the inlet manifold 5. It is configured to supply Furthermore, as is clear from FIGS. 2 and 3, the edge of the communication point 8 is used as a clockwise stopper for the on-off valve 9, and the edge of the communication point 8 is used as a counterclockwise stopper provided on the inner circumferential walls of both passages. Protrusions are used.

As shown in FIG. 4, the pressure detection means 10 includes:
An inlet 14 is opened at one end of the cylindrical cylinder 13 in the axial direction to communicate with the inlet manifold 5.
It has an atmosphere opening port 15 that is open to the atmosphere at the other end, and further has an outlet 16 on one side in the radial direction.
This outlet 16 is divided into a chamber on the inlet 14 side and a chamber on the atmosphere opening port 15 side, which are defined by a piston 17 slidably provided in the axial direction within the cylinder 13, and are selectively separated by the movement of the piston 17. It is becoming easier to communicate with each other. That is, the piston 17 is normally urged toward the inlet 14 by both the spring 18 pressure and the atmospheric pressure, and at that time, the piston 17 is biased toward the inlet 14 side.
6 communicates with the chamber on the side of the atmosphere opening 15, and atmospheric pressure is released from the outlet 16. When the pressure inside the inlet manifold 5 exceeds both of the above pressures,
A control valve 10A is configured which pushes the piston 17 toward the atmosphere opening port 15 side against these pressures, communicates the outlet 16 with the chamber on the inlet side 14, and releases the pressure inside the inlet manifold 5 from the outlet 16. ing.

The thickness of the piston 17 is made larger than the diameter of the outlet 16 in order to allow the outlet 16 to selectively communicate with each chamber even during the transition period. Therefore, as shown in FIGS. 5A to 5C, the control valve 10
The characteristic of A is that when the inlet manifold 5 is initially OFF, it is ON only when the internal pressure P of the inlet manifold 5 exceeds a predetermined pressure _P1 , that is, the inlet 14 and the outlet 16 communicate with each other; When the internal pressure P of the inlet manifold 5 becomes less than the predetermined pressure _P2 , the air release port 1 is turned OFF.
5 and the outlet 16 come into communication. however,
If the thickness of the piston 17 is made the same as the diameter of the outlet 16,
P ₁ = P ₂ , that is, at a given pressure P ₁ = (P ₂ )
ON-OFF switching is performed.

As shown in FIG. 6, the valve actuating means 11 is an actuator 11A whose inlet 20 is connected to the outlet 16 of the control valve 10A, and has substantially the same structure as the control valve 10A, except for the following points: The piston rod 21 protrudes from the atmosphere opening 22 instead of having something corresponding to the outlet 16. This piston rod 21 is connected to an arm 12 connected to the on-off valve 9. As shown in the figure, when the control valve 10A is OFF, the piston rod 21 is drawn into the cylinder 24 by the biasing force of the spring 23, and conversely, when the control valve 10A is ON, as shown in FIG. A spring 23 constant that biases the piston 25 so that the internal pressure of the inlet manifold 5 flowing into the piston 20 pushes out the piston rod 21 with a force greater than a full stroke against both spring 23 pressure and atmospheric pressure. Set.

The operation of this embodiment having the above configuration will be described.

First, when the pressure inside the inlet manifold 5 is P<P ₁ in the engine low speed rotation range,
The control valve 10A is turned OFF, atmospheric pressure is released to the inlet 20 of the actuator 11A connected thereto, as shown in FIG. 6, and the piston rod 21 is drawn into the cylinder 24. piston rod 2
1 is drawn into the cylinder 24, the arm 12 rotates counterclockwise as shown in FIG. Therefore, turbo supercharger 3
The supercharged air enters directly into the inlet manifold 5 via the shortest distance without passing through the intercooler 4.
In this case, the intercooler 4 side of the main passage 6 is completely cut off from the bypass passage 7, so there is no need to fill the entire volume of the intercooler 4 and both passages from this to the communication point 8 with supercharging pressure. ,
Since it is only necessary to fill the volume of the bypass passage 7 which is the shortest distance, a large amount of air is not required and it does not take much time to increase the pressure inside the inlet manifold 5. Furthermore, even if the pressure in the inlet manifold 5 is not low from the beginning, but is initially above the predetermined pressure P ₂ and gradually drops to below P ₂ by operating the accelerator, the control valve 10A is Since the actuator 11A is switched from ON to OFF at _two pressure points and the actuator 11A is actuated at once, the on-off valve 9 can be turned ON/OFF instantly. Therefore, the half-open state of the on-off valve 9 can be eliminated, and the accelerator response can be improved as much as possible not only in the low-speed rotation range but also when shifting to the low-speed rotation range.

Next, when the pressure inside the inlet manifold 5 is P>P ₂ in the engine high speed range,
The control valve 10A is turned on, and the high pressure in the inlet manifold 5 is released to the inlet 20 of the actuator 11A connected thereto, as shown in FIG. 7, and the piston rod 21 is pushed out from the cylinder 24. When the piston rod 21 is pushed out from the cylinder 24, the arm 12 is pushed out as shown in FIG.
rotates clockwise to lower the on-off valve 9, closing the bypass passage 7 and opening the main passage 6.
Therefore, the supercharged air from the turbocharger 3 is cooled through the intercooler 4 and then introduced to the inlet manifold 5. In this case as well, the control valve 10A changes from OFF to ON at _two points at the predetermined pressure P.
Since the switch is switched to , the on-off valve 9 can be turned ON/OFF instantaneously. This makes it possible to increase the filling efficiency as much as possible upon transition to the high speed rotation range.

In this way, according to the above embodiment, the control valve 10A is provided between the inlet manifold 5 and the actuator 11A that operates the on-off valve 9, and the pressure inside the inlet manifold 5 is increased enough to drive the actuator 11A. Since the pressure inside the inlet manifold 5 is transmitted to the actuator 11A when a certain boost pressure is obtained, the on-off valve 9 can be opened and closed instantly, improving the accelerator response, especially in the low-speed rotation range. It can be improved as much as possible. Also,
A bypass passage 7 is formed by bringing the upstream side and the downstream side of the main passage 6 into contact at one point,
Since all of the bypass passages 7 are replaced by the main passage 6, the structure of the bypass passage is extremely simple, and complete switching between the main passage 6 and the bypass passage 7 can be achieved by simply providing one on-off valve 9 at the communication point 8. Since it can be done, the intercooler 4
There is no need to sacrifice performance, such as reducing the capacity of the device.

FIG. 8 shows a modification of the embodiment shown in FIGS. 2 and 3. The difference from FIGS. 2 and 3 is that the upstream and downstream sides of the main passage 6 have the same flow. A communication point 8 is formed by contacting each other in the same direction, and two on-off valves 9a and 9b are provided which meet at the center with each edge of this communication point 8 as a pivot point, and these on-off valves 9 are connected to the actuator 11A. The point is that the link mechanism 30 connected to the piston rod 21 performs opening and closing operations at the same time.
As a result, even when the bypass passage 7 is open (dotted line position in the figure), the supercharging air can be guided without changing direction, and the flow resistance can be reduced in the same way as when the main passage 6 is open. There is.

FIG. 9 also shows another modification, and the difference from the above-mentioned one is that a pressure sensor 10B outputs an electric signal instead of the control valve 10A, and that the output signal of the pressure sensor 10B is used. Operating solenoid valve 1
0C, this has the advantage that the predetermined pressure can be set arbitrarily.

[Effects of the invention] In summary, this invention provides the following excellent effects.

(1) Since the on-off valve can be turned ON/OFF instantaneously rather than gradually based on the pressure in the inlet manifold, the pressure in the inlet manifold can be rapidly increased, and the pressure in the inlet manifold can be increased rapidly. Accelerator response can be improved as much as possible.

(2) When the bypass passage opens, the main passage including the intercooler is completely cut off from the bypass passage, so there is no deterioration in response due to a temporary increase in passage volume.

(3) Since a bypass passage is formed that connects the upstream side and downstream side of the main passage at one point, all of the bypass passages can be shared by the main passage, which is economical, and the bypass passage can be made to have the shortest distance. .

[Brief explanation of drawings]

The figures show a preferred embodiment of the intake system for a turbocharged engine according to this invention, in which Fig. 1 is a schematic diagram of the overall configuration, Figs. 2 and 3 are explanatory diagrams of the operation of the on-off valve, FIG. 4 is a cross-sectional view of a control valve that is an example of pressure detection means, FIG. FIG. 8 is an explanatory diagram of the operation of an actuator which is an example of a valve operating means using a valve, FIG. 8 is an explanatory diagram of the operation of a modification of the on-off valve, and FIG. 9 is a schematic configuration diagram showing a modification of the pressure detection means. In the figure, 1 is an engine with a turbocharger, 3 is a turbocharger, 4 is an intercooler, 5 is an inlet manifold, 6 is a main passage, 7 is a bypass passage, 8 is a communication point, and 9 is an on-off valve. , 10 is a pressure means, 10A is a control valve, 10B is a pressure sensor, 10
C is a solenoid valve, 11 is a valve operating means, and 11A is an actuator.

Claims (1)

[Scope of claim for utility model registration] (1) The main passage from the turbocharger to the inlet manifold via the intercooler,
The main passage is formed by drawing the upstream and downstream sides of the intercooler toward each other, overlapping a part of them, connecting them, and communicating the overlapping parts with each other, and leading directly from the turbocharger to the inlet manifold. A bypass passage is provided at a communication point between the bypass passage and the main passage, and by closing the communication point, supercharging air is supplied from the turbo supercharger to the inlet manifold via the intercooler, and the communication point is opened. an on-off valve that thereby cuts off the supply of supercharging air to the intercooler and supplies supercharging air directly from the turbocharger to the inlet manifold; a pressure detection means that detects the pressure in the inlet manifold; A turbo supercharger equipped with a valve operating means that closes the on-off valve when the signal from the pressure detection means exceeds a predetermined pressure and opens the on-off valve when the signal is below the predetermined pressure. Engine intake system. (2) The pressure detection means is a control valve that releases pressure when the pressure in the inlet manifold exceeds a predetermined pressure, and the valve actuation means operates the on-off valve to a full stroke using the pressure released from the control valve. The intake system for a turbocharged engine according to claim 1, which is an actuator that is actuated to close the on-off valve. (3) Utility model registration claim 1, characterized in that the pressure detection means is comprised of a pressure sensor that outputs an electrical signal, and a solenoid valve that is activated by the output signal of the pressure sensor. Intake system for the turbocharged engine described.