JPH0515540Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a supercharging pressure control device for a turbocharger such as a turbocharger used in an internal combustion engine of a vehicle such as an automobile.

BACKGROUND ART Turbochargers used in internal combustion engines of vehicles such as automobiles are generally equipped with a boost pressure control device to prevent boost pressure from exceeding a set pressure in order to protect the internal combustion engine. This boost pressure control device uses an exhaust bypass method that selectively opens a wastegate port that opens at the turbine inlet and serves as an exhaust bypass port using a wastegate valve to bypass exhaust energy to the turbine. This type of supercharging pressure control device is well known, and is disclosed in, for example, Japanese Utility Model Application No. 60-52348.

Problems to be Solved by the Invention The waste gate valve of the boost pressure control device as described above is generally opened and closed by a valve that applies exhaust gas pressure in the turbine chamber in the valve opening direction for fail-safe purposes. Therefore, when the exhaust gas pressure in the turbine chamber increases, the valve moves to a larger opening position due to the exhaust gas pressure than the opening position that is intended to be set by the valve opening/closing mechanism that controls the opening/closing position of the valve. Being pushed away. Therefore, the opening/closing control of the wastegate valve that controls the wastegate port must be set in consideration of the fact that the valve receives a driving force in the opening direction due to the exhaust gas pressure in the turbine chamber.

As mentioned above, the wastegate valve that selectively releases exhaust gas from the inlet of the turbocharger turbine by bypassing the turbine is controlled by an actuator operated by the pressure of air supply at the outlet of the compressor of the turbocharger. In a boost pressure control device that opens a waste gate valve in response to an increase in supply air pressure at the outlet of a turbocharger compressor,
As the output of the internal combustion engine increases and the rotational speed increases,
The increased exhaust gas flow resistance in the exhaust system increases the exhaust pressure of the internal combustion engine; on the one hand, this increased exhaust gas pressure forces the wastegate valve to open wider, and on the other hand, In this case, even if the pressure at the turbocharger compressor outlet is the same, the exhaust pressure at the engine outlet increases, reducing the effect of charge air supercharging.
The wastegate valve that opens and closes the wastegate port is a swing valve that opens and closes by rotating a pivot, and the pivot is rotated by a valve drive lever, which controls the supply at the outlet of the supercharger compressor. If the rotation is driven by an actuator operated by the air pressure, as the engine output gradually increases with the engine speed, the valve opening action by the actuator and the exhaust gas at the turbocharger turbine inlet will increase. Due to the combined effect of the valve opening effect due to pressure, the opening degree of the wastegate valve that is opened gradually becomes excessive, and the turbo supercharger may not function sufficiently, and the output of the internal combustion engine may not be sufficiently increased.

The present invention provides a supercharging pressure control device that does not unnecessarily increase the opening amount of the waste gate valve in the high rotation range and allows the turbocharger to function satisfactorily in the high rotation range. is intended to provide.

Means for Solving the Problems According to the present invention, the above-mentioned object is achieved by using a valve that is rotatably supported by a pivot shaft and is biased in the valve opening direction by internal combustion engine exhaust gas at the inlet of a supercharger turbine. a swing valve that opens and closes a waste gate port in order to selectively divert exhaust gas of the internal combustion engine from a supercharger turbine in a state in which the internal combustion engine is an actuator that rotationally drives the valve drive lever by the pressure of supply air at the outlet of the supercharger compressor; and an engagement between the valve drive lever and the actuator as the valve drive lever rotates in a valve opening direction. This is achieved by a boost pressure control device for a turbocharger having engagement position changing means for moving the position away from the pivot axis of the swing valve.

Effects and effects of the invention According to the above-described configuration, as the output of the internal combustion engine increases, its rotational speed increases, and as the exhaust gas pressure increases, the pressure of the air supply at the outlet of the turbocharger compressor increases, and the waist As the opening degree of the gate valve increases, the engagement position between the valve drive lever and the actuator deviates away from the pivot axis of the swing valve, and the amount of rotation of the swing valve relative to the actuation deviation of the actuator becomes relatively small. Even if the wastegate valve has a structure in which the pivot of the swing valve is rotated via the valve drive lever by the actuator operated by the air supply pressure at the outlet of the supercharger compressor, it is possible to cope with the increase in output of the internal combustion engine. Correction control can be performed to relatively reduce the increase in the opening of the wastegate valve, and if the wastegate valve opens too much when the internal combustion engine is at high output and high rotational speed, the turbo supercharger may be damaged when the internal combustion engine is under high load and high rotational speed. The inconvenience of not being able to obtain sufficient operation can be avoided.

Embodiments Hereinafter, the present invention will be described in detail with reference to embodiments with reference to the accompanying drawings.

FIG. 1 shows one embodiment of a turbocharger according to the present invention. In FIG. 1, reference numeral 10 indicates a turbine housing that constitutes a turbine chamber 12. As shown in FIG. The turbine housing 10 includes a turbine chamber 1
The turbine chamber 2 has an exhaust gas inlet passage 14 for guiding exhaust gas to the turbine chamber 12, and an exhaust gas outlet passage 16 for discharging exhaust gas from the turbine chamber 12. A turbine wheel 18 is arranged in the turbine chamber 12 . The turbine wheel 18 is connected to a compressor wheel 24 of a compressor chamber 22 by a shaft 20, and is rotated by exhaust energy supplied to the turbine chamber 12 to rotate the compressor wheel 24 and perform intake supercharging. It's summery.

The turbine housing 10 is provided with a wastegate port 26 that opens into the exhaust gas inlet passage 14 . The wastegate port 26 communicates with the exhaust gas outlet passage 16 through a bypass exhaust gas passage 28 that bypasses the turbine chamber 12 .

A swing valve 30 is rotatably attached to the turbine housing 10 via a pivot shaft 32 . The swing valve 30 rotates around the pivot 32 to open the waste gate port 2.
6 to open and close. One end of a valve drive lever 34 is attached to the pivot 32,
The valve drive lever 34 rotates clockwise in the figure to rotationally displace the swing valve 30 in the valve opening direction. The valve drive lever 34 is provided with an elongated hole 36 extending in a direction away from the pivot 32 on its free end side. An engagement pin 44 provided at the tip of a rod 42 of a diaphragm device 40 is slidably engaged with the elongated hole 36.

The diaphragm device 40 includes a diaphragm chamber 46
In response to an increase in the pressure introduced into the valve, the rod 42 is driven to the right in the figure, ie, in the valve opening direction, against the spring force of the compression coil spring 48.
The diaphragm chamber 46 communicates with the compressor chamber 22 through a passage 50, and is configured to receive boost pressure from the compressor chamber 22.

The turbine housing 10 has a long cam groove 5.
2, and an engagement pin 44 is slidably engaged with this cam groove 52. The cam groove 52 is provided to be inclined with respect to the lever length direction of the valve drive lever 34 in the valve closing position, and engages with the elongated hole 52 of the engagement pin 44 as the valve drive lever 34 rotates in the valve opening direction. The position is displaced in a direction away from the pivot 32.

According to the above configuration, the pressure introduced into the diaphragm chamber 46 increases as the boost pressure increases,
When this reaches a predetermined value, the rod 42 moves to the right in the figure against the spring force of the compression coil spring 48, and accordingly, the valve drive lever 34 moves toward the pivot 32.
At the same time, the swing valve 30 also moves clockwise in the figure, that is, in the valve opening direction, and the swing valve 30 also moves in the valve opening direction in the figure, and the waste gate port 26
will be opened. As a result, a portion of the exhaust gas flowing from the exhaust gas inlet passage 14 toward the turbine chamber 12 bypasses the turbine chamber 12 and flows, thereby suppressing an increase in supercharging pressure.

As described above, when the valve drive lever 34 rotates in the valve opening direction, it is guided by the cam groove 52 and the engagement pin 4
4 is displaced in a direction away from the pivot shaft 32, and the effective lever length of the valve drive lever 34 relative to the diaphragm device 40 is increased,
The rotation angle of the valve drive lever 34 with respect to the movement of the diaphragm device 40, that is, the movement of the rod 42, decreases, that is, the drive rate (drive sensitivity) of the valve drive lever 34 by the diaphragm device 40 decreases, and the rotation angle with respect to the movement of the diaphragm device 40 decreases. The opening amount of the swing valve 30 becomes smaller.

As mentioned above, as the boost pressure increases, in other words, as the exhaust gas pressure increases, the diaphragm device 4
As the opening change of the swing valve 30 decreases with respect to the movement of the swing valve 30, the equilibrium relationship between this and the exhaust gas pressure that acts as a force in the opening direction of the swing valve 30 causes the exhaust gas pressure to increase in the high rotation range. At this time, the swing valve 30 is prevented from opening too much, and the required supercharging pressure is ensured even at this time, so that the turbo supercharger can perform sufficient supercharging even in the high rotation range. As a result, the output of the internal combustion engine can be sufficiently increased.

FIG. 2 shows the boost pressure control characteristics with respect to engine speed. In FIG. 2, the solid line shows the case using the supercharging pressure control device according to the present invention, and the broken line shows the case using the conventional supercharging pressure control device. As is clear from this graph, in the conventional type, the boost pressure decreases as the engine speed increases, and the turbocharger does not function sufficiently in the high speed range, so the increase in output of the internal combustion engine is insufficient. However, according to the supercharging pressure control device according to the present invention, the required supercharging pressure is ensured even in a high rotation range, and the output of the internal combustion engine can be sufficiently increased.

The shape of the cam groove 52 may be selected from a straight line, a broken line, a curved line, etc., as appropriate, depending on the required boost pressure control characteristics with respect to the engine speed.

Although the present invention has been described above in detail with reference to specific embodiments, it is understood that the present invention is not limited to this and that various embodiments are possible within the scope of the present invention. This will be obvious to businesses.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing one embodiment of a boost pressure control device for a turbocharger according to the present invention, and FIG. 2 is a graph showing boost pressure control characteristics with respect to engine speed. 10...Turbine housing, 12...Turbine chamber, 14...Exhaust gas inlet passage, 16...Exhaust gas outlet passage, 18...Turbine wheel, 20
... shaft, 22 ... compressor chamber, 24 ... compressor wheel, 26 ... waste gate port, 28 ... bypass exhaust gas passage, 30 ... swing valve, 32 ... pivot, 34 ... valve drive lever, 36... Long hole, 40... Diaphragm device, 42... Rod, 44... Engaging pin, 4
6...Diaphragm chamber, 48...Compression coil spring, 50...Passage, 52...Cam groove.

Claims (1)

[Scope of utility model registration request] Rotatably supported by a pivot shaft and biased in the valve opening direction by the internal combustion engine exhaust gas at the turbocharger turbine inlet to selectively divert the internal combustion engine exhaust gas from the turbocharger turbine. a swing valve that opens and closes the waste gate port; a valve drive lever that is attached to the pivot of the swing valve; A turbo supercharger comprising: an actuator that is rotationally driven; and an engagement position changing means that moves the engagement position of the valve drive lever and the actuator away from the pivot of the swing valve as the valve drive lever rotates in the valve opening direction. Aircraft supply pressure control device.