JPS6237943Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a supercharging device having a turbocharger that allows effective boost pressure to be obtained at all times over the entire engine speed range.

A turbocharger uses energy from exhaust gas to rotate an exhaust turbine and uses this power to drive a compressor to increase boost pressure and increase engine output.

However, conventional supercharging devices having a turbocharger have the disadvantage that when the engine speed is low and the exhaust gas flow rate is low, the turbine speed is also low and effective boost pressure cannot be obtained. Conversely, when the engine speed is high and the exhaust gas flow rate is high, the turbine overspeeds and the boost pressure becomes too high, which is dangerous, so an exhaust bypass path called a wastegate is installed to prevent this. is the current situation.

By the way, prior art for supercharging devices that can handle exhaust gases in different states includes, for example, introducing pulsating gases of different phases into the turbine separately in order to fully utilize the dynamic pressure energy of the pulsating gases. In the so-called double entry type turbocharger, the turbine is divided into two by a partition wall, and the partition wall is extended to the partition wall between the respective turbine nozzles to guide gas, as disclosed in Japanese Utility Model Application Publication No. 50-131413. I have an idea. However, this publication does not disclose any means for using the conventional double-entry supercharger for purposes other than its intended use.

As another prior art, two gas supply passages provided in the double-entry turbocharger are separated by a partition, a branch pipe for bypassing the turbocharger is opened in the partition, and a common operating bypass valve is provided here. There is an idea in Utility Model Application Publication No. 55-88018. This prior art aims to simplify the device and ensure reliable operation by replacing the conventional two bypass valves with one bypass valve. There is no disclosure of any means of utilization other than the use of a conventional double-entry supercharger.

Therefore, an object of the present invention is to provide an excellent supercharging device that can obtain effective boost pressure over the entire engine speed range.

The configuration of the supercharging device of the present invention to achieve the above objectives is to provide a common turbine shaft with large-diameter and small-diameter turbine wheels, and selectively direct exhaust gas to the gas injection nozzles of each of the large and small turbine wheels. a gas passage that is provided with a switching valve that supplies gas and that returns the turbine exhaust gas to each of the nozzles;
The present invention is characterized in that a switching valve is provided in the passage, the switching valve interlocking with the switching valve and allowing gas to flow back to the turbine on the side to which the switching valve does not supply gas.

The supercharging device of the present invention introduces exhaust gas into the turbine chamber with a wide cross section that matches the supercharging efficiency when an engine with high exhaust gas emissions is running at high speed. During rotation, exhaust gas is introduced into the turbine chamber with the narrow cross section that matches this, and the gas discharged from the turbine chamber is circulated to the turbine chamber on the unused side, thereby creating a negative pressure in the turbine chamber. By preventing this, it acts to provide effective supercharging efficiency over the entire rotation range of the engine.

When implementing the present invention, the switching valve for exhaust gas supplied to the turbine chamber and the switching valve for circulating the exhaust gas on the turbine outlet side to the unused turbine chamber can be configured by the same valve.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the main parts of an embodiment of the supercharging device of the present invention, and the turbocharger T includes a compressor wheel 11 and a compressor housing 1.
The compressor wheel 10 is composed of a compressor section 10 consisting of two wheels, and a turbine section 20 that drives a compressor wheel 11. Further, the turbine wheel 30 of the turbine section 20 connected to the compressor wheel 11 via the turbine shaft 13 has two types of turbine wheels having different diameters, a low-speed turbine wheel 31 and a high-speed turbine wheel 32, which share the turbine shaft 13. It has a structure that looks like it is equipped with two turbines, and the turbine housing 22
is internally divided into a first turbine chamber 23 and a second turbine chamber 24 in the axial direction by a partition wall 21 so that exhaust gas can be supplied independently to the low-speed turbine wheel 31 and the high-speed turbine wheel 32, respectively. It is divided into two parts. And the first and second
The turbine chambers 23 and 24 have a cross-sectional area in the axial direction that is larger than that of the first turbine chamber 24 than that of the second turbine chamber 24.
3 is smaller, and the nozzle portion 23a of the first turbine chamber 23 is set smaller than the nozzle portion 24a of the second turbine chamber 24.

Furthermore, the turbine section 2 configured as described above
The exhaust passage 50 that supplies exhaust gas from the engine 70 to the engine 70 is divided into two by a partition wall 43 near the turbine section 20 (turbine housing section 22), and the first exhaust passage 50 supplies exhaust gas to the first turbine chamber 23. The two exhaust passages 40 are composed of an exhaust passage 41 and a second exhaust passage 42 that supplies exhaust gas to the second turbine chamber 24 . Further, a turbocharger T is provided on the outer wall of the exhaust passage 50 at the gathering part of the first and second exhaust passages 41 and 42 of the two exhaust passages 40.
Reflux passages 26 and 27 communicating with the exhaust passage 25 on the downstream side of the turbine section 20 are respectively opened and provided.

Then, a gathering portion 44 of the two exhaust passages 40 is provided.
is provided with two reflux passage-exhaust passage switching valves that operate independently, the first switching valve 51 switching between the reflux passage 26 and the first exhaust passage 41, and the second switching valve 52 switching between the reflux passage 26 and the first exhaust passage 41. The exhaust passage 27 and the second exhaust passage 42 are switched. In this example, these first
And second switching valves 51 and 52 are rotatably provided on the outer wall of the exhaust passage 50, and when one switching valve closes the exhaust passage, the other switching valve opens the exhaust passage, and the closed exhaust passage is recirculated. This passage communicates with an exhaust passage 25 on the downstream side of the turbine section 20 of the turbocharger T.

The first and second switching valves 51 and 52 can be opened and closed independently by actuators 61 and 62, respectively.
0, and the first and second switching valves 51 and 52 are opened and closed by a control signal from the control device 60. The control device 60 includes a rotation speed sensor 64 for the engine 70.
The signals from the exhaust brake switch 65 and the exhaust brake switch 65 are inputted to the control device 60.
processes the signal from the rotation speed sensor 64 internally, and when the engine speed is lower than the set rotation speed, the actuators 61 and 62 close the first switching valve 51, close the recirculation passage 26, and open the first exhaust passage 41. Set the second switching valve 52 to the open side and connect the second switching valve 52 to the second exhaust passage 42
The second exhaust passage 42 is connected to the exhaust passage 25 on the downstream side of the turbine section 20 via the recirculation passage 27.
Let me understand. In addition, when the engine speed exceeds the set speed, the first switching valve 51 is set to the side that closes the first exhaust passage 41, and the second switching valve 52 is set to the side that closes the first exhaust passage 41.
Set the exhaust passage 42 to the open side.

Further, when the exhaust brake switch 65 is turned on and enters the exhaust brake state, the control device 65
0 drives the actuators 61 and 62 so that both the first and second switching valves 51 and 52 close the first and second exhaust passages 41 and 42. 63 is a battery.

2 to 4 show details of the turbine wheel 30 described above. The turbine wheel 30 of the present invention has a structure in which two types of turbine wheels having different diameters are superposed and mounted in parallel. That is, in the turbine wheel 30, a low-speed turbine wheel 31 with a small diameter as shown in FIG. 4 is first attached to the turbine shaft 13 shown in FIG. , and then the side peripheral portions 3 of the plurality of turbine blades 34 provided in the rectifying section 33.
5, a high-speed exhaust gas rectifying section 36 of a high-speed turbine wheel 32 having a large diameter is fixed as shown in FIG. At this time, the rotation axis of the high-speed turbine wheel 32 is the turbine wheel 31
Needless to say, it must be aligned with the rotation axis of the A plurality of turbine blades 37 are provided in the rectifying section 36.

The turbine chamber side of the high-speed exhaust gas rectifying section 36 is placed close to the partition wall 21, so that the exhaust gas from the first turbine chamber 23 is transferred to the low-speed turbine wheel 31, and the exhaust gas from the second turbine chamber 24 is placed close to the partition wall 21. is ejected onto the high-speed turbine wheel 32 and collides with each turbine blade 34, 37.

In the supercharging device of the present invention configured in this way,
When the rotation speed of the engine 70 is low, the control device 60
The first switching valve 51 opens the first exhaust passage 41 to communicate with the exhaust passage 50, and the second switching valve 5
2 closes the second exhaust passage 42, the exhaust gas flows through the first exhaust passage 4 as shown by arrow L in FIG.
1, enters the first turbine chamber 23, and is ejected to the low-speed turbine wheel 31. Since the first turbine chamber 23 has a narrowed nozzle portion 23a and a small cross-sectional area, the exhaust gas ejection energy increases even if the exhaust gas flow rate is small, so that the turbine shaft 13 is rotated at a high rotation speed. The compressor section 1 can rotate even at low engine speeds.
The boost pressure obtained at 0 increases.

At this time, the second exhaust passage 4 into which exhaust gas does not flow
2 communicates with the exhaust passage 25 on the downstream side of the turbine section 20 of the turbocharger T through the recirculation passage 27, so that the inside of the second exhaust passage 42 does not become negative pressure due to the rotation of the turbine wheel 30.
Turbine wheel 30 rotates smoothly.

When the engine speed increases and exceeds the set speed, the control device 60 controls the second exhaust passage 42.
communicates with the exhaust passage 50 , and the first exhaust passage 41 communicates with the exhaust passage 25 on the downstream side of the turbine section 20 via the reflux passage 26 . Then, the exhaust gas flows into the second exhaust passage 42, enters the second turbine chamber 24, as shown by the broken line H in FIG. 1, and is ejected to the high-speed turbine wheel 32. Since the nozzle part 24a of the second turbine chamber 24 is larger than the nozzle part 23a of the first turbine chamber 23, the ejection energy of the exhaust gas is reduced, so that the turbine shaft 13 does not over-rotate even if the exhaust gas flow rate increases. First, even when the engine speed is high, the boost pressure obtained by the compressor section 10 does not reach overboost pressure.

Further, in the supercharging device of the present invention, when the driver turns on the exhaust brake switch 65 to operate the exhaust brake, the control device 60 controls the first and second exhaust brakes.
The switching valves 51 and 52 are connected to the first and second exhaust passages 4
1 and 42, it can also be used as an exhaust brake.

As explained above, the supercharging device of the present invention has large-diameter and small-diameter turbine wheels installed on a common turbine shaft, and selectively injects gas into nozzles that inject gas to each of the large and small turbine wheels. a gas passage that is provided with a switching valve for supplying gas and that returns the turbine exhaust gas to each of the nozzles; and a switching valve that is connected to the switching valve in the passage and that returns gas to the turbine on the side to which the switching valve does not supply gas. By installing a valve and using these two types of turbine wheels depending on the engine speed, effective boost pressure can be obtained over the entire engine speed range, so the turbo effect can be obtained from low engine speeds. It has the effect of being

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the essential parts of a turbocharger showing an embodiment of the present invention, Fig. 2 is a view of the twin turbine wheel shown in Fig. 1 in the direction of arrow A, and Fig. 3 is a view of the turbine wheel shown in Fig. 2. The perspective view, FIG. 4, is a perspective view of only the low-speed turbine wheel from which the outer high-speed turbine wheel of FIG. 3 has been removed. 10... Compressor part, 13... Turbine shaft, 20... Turbine part, 21... Partition wall, 2
2... Turbine housing, 23... First turbine chamber, 24... Second turbine chamber, 31... Low speed turbine wheel, 32... High speed turbine wheel, 33, 36... Rectifier, 34, 37... ... Turbine blade, 35 ... Side peripheral part, 40 ... Two exhaust passages, 43 ... Partition wall, 50 ... Exhaust passage, 51 ... First switching valve, 52 ... Second switching valve,
60...control device, 61, 62...actuator, 64...rpm sensor, 65...exhaust brake switch, 70...engine.

Claims (1)

[Scope of utility model registration request] A common turbine shaft is provided with large-diameter and small-diameter turbine wheels, and a switching valve is provided to selectively supply exhaust gas to the gas injection nozzles of each of the large and small turbine wheels, so that the exhaust gas of the turbine is A supercharging device characterized in that a gas passage is provided for returning gas to a nozzle, and a switching valve is provided in the passage, the switching valve interlocking with the switching valve and allowing gas to be returned to a turbine on a side to which the switching valve does not supply gas.