JPS6045739B2 - Boost pressure control device for supercharged engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a boost pressure control device, and particularly to a device for controlling boost pressure by bypassing exhaust gas flowing into a turbine of an exhaust turbo supercharger.

In general, vehicles, especially automobiles, become much easier to use if they have better starting or acceleration characteristics.

For this reason, various specifications are determined so that the output/torque peak of the internal combustion engine is located as low as possible. This does not change even if the internal combustion engine is equipped with an exhaust turbo supercharger.
Therefore, it is customary to match the specifications of the supercharger to low speed. However, since the turbocharger operates using the energy of exhaust gas, in the above-mentioned internal combustion engine matched to low speed, the supercharging pressure becomes excessive as the engine speed increases, resulting in the maximum explosion pressure. This rise in temperature leads to various problems. Therefore, the excess exhaust gas is bypassed without flowing into the turbine of the supercharger.

However, because conventional supercharging systems rapidly discharge excess exhaust gas, the supercharging pressure suddenly drops significantly, resulting in poor feeling during vehicle operation and a drop in exhaust temperature. This was causing problems such as abnormal increase in smoke density and deterioration of smoke density.

Also, Japanese Patent Publication No. 38-15256 and Patent No. 147
95 Sae describes a supercharging device in which an exhaust bypass valve in an exhaust turbo supercharger is opened and closed by hydraulic pressure controlled by supercharging air, but none of them are primarily controlled. Therefore, there is a possibility that the above-mentioned rapid fluctuations in supercharging pressure cannot be sufficiently alleviated.

The present invention was devised in view of the above-mentioned points, and it prevents sudden fluctuations in the supercharger pressure, improves the feeling during vehicle operation, and also prevents abnormal increases in exhaust temperature and deterioration of smoke density. The purpose is to prevent this problem and obtain ideal output performance.The gist of this is that the first and second grooves are provided with different phases in the sliding direction, and the second groove is installed in a slider operated by supercharging pressure. 1. A boost controller that engages the slam of the second control valve is installed in the path from the high-pressure air source to the air cylinder for actuating the switching valve in the turbine bypass path, and when the first and second set boost pressures are reached, A supercharging pressure control device for a supercharged engine, wherein the first and second control valves sequentially connect the two passages connecting the control valves and the air cylinder side of the passage to the atmosphere or high-pressure air. The present invention will be explained below with reference to an embodiment shown in FIG.

Reference numeral 1 denotes an internal combustion engine having an exhaust pipe 2 and an intake pipe 3; 4 an exhaust turbo supercharger having a turbine 5 operated by the exhaust gas of the internal combustion engine 1; and a compressor directly connected to the turbine 5 via an output shaft 6. 7, and supplies air compressed by the compressor 7 to the intake pipe 3.

8 is an exhaust duct that communicates the exhaust pipe 2 and the turbine 5 of the exhaust turbo supercharger 4; A valve groove, for example, a switching valve 11, is provided to connect and disconnect communication between the passage 9 and the turbine bypass path 10.

When the two passages are communicated by the switching valve 11, a part of the exhaust gas is discharged to the turbine outlet side without flowing into the turbine 5. Reference numeral 12 denotes an air cylinder that operates the switching valve 11. When high-pressure air flows into the cylinder 13, the piston 14 operates the switching valve 11 against the force of the spring 15, thereby establishing communication between the exhaust passage 9 and the turbine bypass passage 10. cut off.

16 is an air tank as a high pressure air source, for example engine 1
18 is an air controller consisting of an air chamber 19 and two on-off valves 21 and 22 interlocked by a solenoid 20, 23 is a main switch for the engine, and 24 is a main switch for the engine. When the switch 23 is closed, the solenoid 20 is energized, the two on-off valves 231 and 22 are pulled upward in the figure, and the inlet 25 is opened to communicate the air tank 16 and the air chamber 19, while the outlet 26 is closed and the air chamber is closed. 19. Separate from outside air.

27 is a diaphragm 2 which branches off from the middle of the intake pipe 3 and the compressor 7 and receives the overpressure air and is displaced against the spring 28.
a first control valve 33 and a second control valve 34 whose stems 33a and 34a are in contact with each other by the urging of springs 31 and 32 at right angles to the sliding movement of the slider 30; A first chamber 36 communicates with the air chamber 19 via a throttle 35, a second chamber 37 and a third chamber 38 communicate with the air cylinder 12 via two passages 37a and 38a, and communicate with the outside air. This is a boost controller consisting of a fourth chamber 39.

The slider 30 is connected to the first and second control valves 33 and 3.
A first groove 40 and a second groove 41 are respectively disposed on the side surfaces of the stems 33a and 34a of No. 4 in contact with each other, and
When no supercharging pressure is applied, the stem 33a of the first control valve 33 is brought into contact with the slider side surface 40a above the first groove 40, and the stem 34a of the second control valve 34 is brought into contact with the second groove 41. There is. In addition, in this state, the first chamber 36 and the second chamber 37
．． The third chamber 38 and the fourth chamber 39 are in communication with each other, and the third chamber 38 and the fourth chamber 39 are cut off.

Furthermore, when the boost pressure increases and reaches the first general constant boost pressure, the stem 33a of the first control valve 33 falls into the first groove 40, and the first control valve 33 opens the first chamber 36 and the second chamber. 37, and the second chamber 37 and the atmosphere are communicated through the aperture 42.

Therefore, the high pressure air in the air cylinder 12 is gradually discharged through the throttle 42. Then, when the supercharging pressure increases and reaches the second set supercharging pressure, the stem 34a of the second control valve 34 protrudes from the second groove 41 and the slider side surface 41
a, and the second control valve 34 communicates the third chamber 38 and the fourth chamber 39, that is, the third chamber 38 and the atmosphere.

Therefore, the air cylinder 12 communicates with the atmosphere not only through the second chamber 37 and the throttle 42 but also through the fourth chamber 39. The supercharging pressure control device for a supercharged engine according to the present invention is constructed as described above, and its operation will be described below. When the main switch 23 is closed, the solenoid 24 is energized, and the two interlocking on-off valves 21,
22 is pulled up as shown by the two-dot chain line in the figure to open the inlet 25 and close the outlet 26. Then air tank 16
The higher pressure air flows from the air chamber 19 through the throttle 35, the first chamber 36, the second chamber 37, and the passage 37a, and flows into the air cylinder 12 to actuate the piston 14 against the spring 15. Therefore, since the piston 14 is interlocked with the switching valve 11, the switching valve 11 is moved to shut off the exhaust passage 9 and the turbine bypass passage 10.

From this state, as the rotation or load increases, the energy of the exhaust gas and the boost pressure also increase.

When the boost pressure reaches the first general constant pressure, the stem 33a of the first control valve 33 falls into the first groove 40 due to the rise of the slider 30, and the first control valve 33 connects with the first chamber 36. The second chamber 37 is cut off to cut off the supply of high-pressure air from the air tank 16 to the air cylinder 12, and the passage 37a, the second chamber 37, and the atmosphere are communicated via the throttle 42. Then, the piston 14 of the air cylinder 12 is actuated by the action of the spring 15, and the high pressure air in the cylinder 13 is slowly discharged to the atmosphere, so that the switching valve 11 gradually connects the exhaust passage 9 and the turbine bypass passage 10. communicate. As a result, a portion of the exhaust gas is gradually discarded from the turbine bypass path 10, so that the amount of exhaust gas flowing into the turbine 5 is gradually reduced.

Therefore, since the rotation of the compressor 7 is suppressed, an appropriate supercharging pressure can be maintained. Also, the high pressure air in the air cylinder 12 is slowly discharged through the throttle 42 and the switching valve 11
If the supercharging pressure abnormally increases due to a sudden load such as acceleration or an increase in engine speed during the transition and reaches the second set supercharging pressure, the stem 34a of the second control valve 34 will move into the second groove 41. It protrudes from the slider side surface 41a.

At this time, the second control valve 34 opens the third chamber 38 and the fourth chamber 39.
, that is, the third chamber 38 and the atmosphere,
High-pressure air from the air cylinder 12 flows through the passage 38a1 to the third chamber 3.
8. Exhausted through the fourth chamber 39 and the aforementioned second chamber 3
It is added to what is discharged from 7 through the throttle 42 and is discharged from both. Therefore, the switching valve 11 quickly expands the communication between the exhaust passage 9 and the turbine bypass passage 10 to reduce the amount of exhaust gas flowing into the turbine 5, thereby preventing an abnormal increase in supercharging pressure. From this state, when the rotation (or load) decreases again and the amount of exhaust gas decreases, the supercharging pressure also decreases, so the process reverses to that described above.

That is, when the supercharging pressure decreases to the second set pressure, the stem 34a of the second control valve 34 falls into the second groove 41, and the second control valve 34 opens the third chamber 38 and the fourth chamber. 39. Further, when the pressure decreases to a first general constant pressure, the stem 33a of the first control valve 33 protrudes from the first groove 40 and comes into contact with the slider side surface 40a, and the first control valve 33 is brought into contact with the first chamber 36. It communicates with the second chamber 37 and blocks communication between the second chamber 37 and the outside air.

As a result, the high pressure air from the air tank 16 is restricted to the 35
The air gradually flows into the cylinder 12 through the air cylinder 12, thereby gradually moving the switching valve 11 in the direction of blocking the exhaust passage 9 and the turbine bypass passage 10.

Therefore, since the amount of exhaust gas to the turbine 5 gradually increases, the supercharging pressure is increased without any fluctuation, and smooth torque can be obtained as described above. Note that when the engine 1 is stopped and the main switch 23 is opened, the on-off valves 21 and 22 of the air controller 18 close the inlet 25 to cut off the inflow of high-pressure air and open the outlet 26, so that the air cylinder The air in the air chamber 12 is exhausted through the second chamber 37, the first chamber 36, and the air chamber 19.

The supercharging pressure control device for a supercharging engine according to the present invention has first and second grooves provided with different phases in the sliding direction, and stems of the first and second control valves are mounted on a slider operated by supercharging pressure. A boost controller is provided in the path leading from the high-pressure air source to the air cylinder for actuating the switching valve in the turbine bypass passage, and when the first and second set boost pressures are reached, the boost controller is engaged with the boost controller. The two passages connecting the two control valves and the air cylinder side of the passage are successively communicated with the atmosphere or high-pressure air, thereby gradually bypassing a portion of the exhaust gas and controlling the amount of exhaust gas flowing into the turbine 5. As a result, wide fluctuations in supercharging pressure caused by sudden bypass as in the past can be prevented, which not only improves the feeling during vehicle operation, but also prevents sudden changes in supercharging pressure. Since this prevents the temperature from decreasing, there is no abnormal rise in exhaust temperature and no deterioration in smoke concentration, making it possible to obtain ideal output performance. Furthermore, in the present invention, even if the boost pressure does not rise abnormally during the process in which the switching valve 11 communicates the exhaust passage 9 and the turbine bypass passage 10, the structure is such that the above-mentioned communication is quickly and completely established. Therefore, an abnormal increase in combustion pressure due to the above-mentioned abnormal increase in pressure can also be avoided.
In addition, compressed air is used instead of using hydraulic pressure such as lubricating oil as in the supercharged engines of the above-mentioned Japanese Patent Publication No. 38-15256 and Japanese Patent No. 14795, which provides a high degree of sealing performance. This is not necessary and has the effect of making the device cheaper.

Further, the valve mechanism that connects and disconnects the communication between the exhaust passage 9 and the turbine bypass path 10 may be a poppet valve 12'' that connects and disconnects communication by sliding, as shown in FIG.

In the above embodiment, high pressure air is caused to flow into the air cylinder 12 to block communication between the exhaust passage 9 and the turbine bypass passage 10, but the boost controller 27 and the air cylinder 12 are connected as shown in FIG. The switching valve 11 is biased by the spring 15 of the air cylinder 12 to cut off communication between the exhaust passage 9 and the turbine bypass passage 10, and high pressure air is allowed to flow into the cylinder 12 at the set boost pressure. The exhaust passage 9 and the turbine bypass passage 10 may be communicated with each other.

[Brief explanation of drawings]

FIG. 1 is a schematic system diagram showing an embodiment of the present invention, FIG.
FIG. 3 is a partially schematic system diagram showing another embodiment of the present invention. 1: Internal combustion engine, 2: Exhaust pipe, 3: Intake pipe, 4: Exhaust turbo supercharger, 5; Turbine, 7; Compressor, 8; Exhaust duct, 9; Exhaust passage, 10; Turbine bypass path, 11; Switching valve, 12; Air cylinder, 14; Piston, 16; Air tank, 18; Air controller, 21, 22; Opening/closing valve,
27; boost controller, 29: diaphragm, 30; slider, 33; first control valve, 34; second control valve, 35,
42: Aperture, 36; First chamber, 37: Second chamber, 38;
Third chamber, 39: Fourth chamber, 40; First groove, 41; Second groove, 37a, 38a; Passage.

Claims (1)

[Claims] 1. A boost controller in which the first and second grooves are provided with different phases in the sliding direction and the stems of the first and second control valves are engaged with a slider operated by boost pressure is connected to a boost controller from a high-pressure air source. The turbine bypass path is provided in a path leading to the air cylinder for actuating the switching valve, and when the first and second set supercharging pressures are reached, the first and second control valves connect both control valves and the air cylinder side of the path. A boost pressure control device for a supercharged engine that sequentially connects two passages to the atmosphere or high pressure air.