JP2686953B2 - Exhaust system for turbocharged engine with exhaust turbocharger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention includes two exhaust turbochargers, and either one or both of them may be selected depending on the operating state of the engine. The present invention relates to an intake device for a supercharged engine that is controlled so as to operate uniformly.

(Prior Art) A turbine driven by exhaust gas of an engine,
An exhaust turbocharger (hereinafter simply referred to as "turbocharger") consisting of an intake air supercharging blower (compressor) connected to this turbine and rotating is widely used to improve the output performance of the engine. However, in order to solve the general drawbacks of this turbocharged engine, such as lack of low-speed torque and poor acceleration response due to turbo lag, it is disclosed, for example, in JP-A-59-147824. As described above, a sequential turbocharger has been proposed. In this sequential turbocharger, two turbochargers are installed so that the turbines and blowers are arranged in parallel in the exhaust passage and the intake passage, respectively, and the number of superchargers to be operated depends on the operating state. By changing or by operating two turbochargers designed for low speed and high speed for a certain degree depending on the operating condition, it is possible to eliminate the above low speed torque shortage and turbo lag. It is something to try.

By the way, in the above sequence turbocharger, the intake passage is branched into two downstream of the air flow meter that detects the intake air amount to determine the fuel injection amount,
Each of the two branch intake passages is provided with each blower of the two turbochargers, and one or both of the branch intake passages is provided with an opening / closing valve for opening and closing the branch passage according to an operating state. With this configuration, a pressure wave is generated in the branch intake passage when the opening / closing valve is opened and closed, and this pressure wave propagates to the upstream side of the intake passage to vibrate the air flow meter, which changes the fuel injection amount. Then, there was a problem that torque fluctuation occurred.

In addition, one of the two exhaust turbochargers is a primary turbocharger and the other is a secondary turbocharger, and the branch intake passage is provided with a blower for the secondary turbocharger. An on-off valve is provided to close the on-off valve in the low engine speed region to operate only the primary turbocharger, and to open the on-off valve in the high engine region to open the primary and secondary turbochargers. When both the feeders are operated, the pressure fluctuation in the secondary side branch intake passage caused by the opening / closing operation of the opening / closing valve is also propagated to the primary side branch intake passage, and the primary side turbo intake Since it affects the rotation of the blower of the supercharger, there is a problem that torque fluctuations are caused also by such a cause, especially in the rotary piston engine.

(Object of the invention) Therefore, the present invention has been made in view of the above circumstances, and an exhaust turbo-type supercharger that prevents torque fluctuations due to the generation of a pressure wave due to the opening / closing operation of the opening / closing valve provided in the branch intake passage. It is an object to provide an intake system for an engine with a machine.

(Structure of the Invention) An intake device for an engine with an exhaust turbocharger according to a first invention of the present application is a two-branch intake air intake formed by branching an intake passage downstream of an air flow meter that detects an intake air amount. In an intake system for an engine, a blower for an exhaust turbocharger is provided in each passage, and an opening / closing valve that opens and closes the branch intake passage according to an operating state is provided in a predetermined branch intake passage. The exhaust turbochargers of the stand are arranged so as to face each other in such a manner that both blowers are located outside, and the branch intake passage portions on the upstream side of both blowers are formed to face each other, and the branch intake passages that face each other. A part is arranged so as to pass above the two exhaust turbochargers.

An intake system for an engine with an exhaust turbocharger according to a second aspect of the present invention is an exhaust turbocharger that includes a turbine driven by exhaust gas and a blower that is provided on a rotating shaft of the turbine and supercharges intake air. Each of the blower of the exhaust turbocharger is provided in each of two branched intake passages formed by branching the intake passage downstream of the air flow meter for detecting the intake air amount. Further, in an intake system of an engine in which an opening / closing valve for opening and closing the branch intake passage according to the operating state is provided in a predetermined branch intake passage, both blowers of the two exhaust turbochargers are placed outside. The branch intake passage portions on the upstream side of both blowers are arranged so as to face each other so that the central axis lines of the branch intake passage portions are substantially aligned with each other, and The branch intake passage portion provided with the aflow meter is arranged so as to form a predetermined angle with respect to the central axis of the intake passage. The exhaust turbocharger is arranged so as to pass above it.

An intake system for an engine with an exhaust turbocharger according to a third aspect of the present invention is an exhaust turbocharger that includes a turbine driven by exhaust gas and a blower that is provided on a rotating shaft of the turbine to supercharge intake air. Each of the blower of the exhaust turbocharger is provided in each of two branched intake passages formed by branching the intake passage downstream of the air flow meter for detecting the intake air amount. In addition, in the intake system of the engine in which the intake cut valve and the exhaust cut valve that open in a predetermined operation region are provided in the intake system and the exhaust system provided with one exhaust turbocharger, Place the exhaust turbocharger on the side of the engine so that the rotation shafts of both exhaust turbochargers are in series with each other, with both turbines located inside and blowers located outside. In addition, the branch intake passage portions on the upstream side of both blowers are formed to face each other, and the branch intake passage portions facing each other are arranged so as to pass above the two exhaust turbochargers. It is characterized by having done.

(Effect of the Invention) According to the first invention of the present application, since the two exhaust turbochargers are arranged so as to face each other in such a manner that both blowers are located outside, the branch intake passage portion connecting the blowers is The passage length is increased, which reduces the influence on the other blower, thereby preventing the torque fluctuation of the engine.

Further, since the upstream branch intake passage portions of both blowers are formed so as to face each other, when the on-off valve is opened and closed, the pressure wave generated in the branch intake passage in which this on-off valve is provided is generated by the other branch intake passage. Can be attenuated by
Therefore, it is possible to prevent a torque fluctuation by avoiding a possibility that the air flow meter malfunctions due to the pressure wave.

In particular, as in the second invention of the present application, the upstream side branch intake passage portions of both blowers are arranged such that the central axis lines of both branch intake passage portions are substantially aligned with each other, and the central axis lines are the above-mentioned air flow meters. When the branch portion of the provided intake passage is arranged at a predetermined angle with respect to the central axis of the intake passage, the above effect is remarkable.

Further, as in the third invention of the present application, two exhaust turbochargers are arranged such that both turbines are located on the inner side and both blowers are located on the outer side. The two exhaust turbochargers can be arranged compactly by arranging the two in series so that they are in series with each other, and the space factor is the best.

In any of the inventions, the branch intake passage portions formed so as to face each other or arranged so that the central axes thereof are substantially aligned are arranged so as to pass above the two exhaust turbochargers. The space factor can be further improved by the presence of the above.

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

FIG. 1 is a diagram schematically showing an intake system of an engine with an exhaust turbocharger according to an embodiment of the present invention, and FIG. 2 is a side view showing a configuration of a main part of a rotary piston engine according to the present invention. Is. In FIG. 1, the exhaust passage 2 for discharging the exhaust gas of the engine 1 is branched midway to form two branched exhaust passages 2a and 2b. Also, Engine 1
The intake passage 3 through which the intake air flows is branched on the downstream side of the air flow meter 4 for detecting the intake air amount, and two branched intake passages 3a and 3b are formed, and merged on the upstream side of the intercooler 5. There is. In the intake passage 3 on the downstream side of the intercooler 5, a throttle valve 6 and a surge tank 7 are provided.
And a fuel injection valve 8 is provided.

A turbine Tp, which is rotationally driven by exhaust gas, is disposed in one of the two branch exhaust passages 2a, 2b, and the turbine Tp is disposed in one of the branch intake passages 3a. The blower Cp is connected via a rotation axis Lp. And these turbine Tp, rotating shaft Lp, blower Cp
The primary side turbocharger 9 is constituted by using as a main element. Similarly, the other branch exhaust passage 2b is provided with a turbine Ts that is rotationally driven by exhaust gas, and the other branch intake passage 3b is provided with a blower Cs, and these turbine Tp and blower Cs are provided. And are connected by a rotation axis Ls to form a secondary turbocharger 10. Both branch exhaust passages 2a and 2b are joined downstream of the turbines Tp and Ts, but the primary turbocharger 9 and the secondary turbocharger 10 are
As is clear from FIG. 2, the turbine T
p and Ts are on the inner side and face each other, and the blowers Cp and Cs are on the outer side so that the rotation axes Lp and Ls are on each other.
Moreover, the rotation axes L _P and L _S are arranged so as to be substantially parallel to the rotation axis of the engine (the eccentric shaft in this embodiment).

Further, the passage portions on the upstream side of the blowers Cp, Cs of the branch intake passages 3a, 3b face each other so that their central axes are substantially aligned at the branch portion branched from the intake passage 3, and are located downstream of the air flow meter. A predetermined angle (about 90 ° in this embodiment as shown in FIG. 2) with respect to the central axis of the intake passage.
The pressure wave generated in one of the branch intake passages 3b is easily propagated to the other branch intake passage 3a side and is less likely to be propagated to the air flow meter 4 side. . The branch intake passage portion is arranged so as to pass above the two exhaust turbochargers.

An exhaust cut valve 11 is arranged in the secondary branch exhaust passage 2b on the upstream side of the turbine Ts. The exhaust cut valve 11 closes the branch exhaust passage 2b in a low rotation range to cut off the supply of exhaust gas to the turbine Ts of the secondary turbocharger 10, and shuts off only the primary turbocharger 9. It is provided for operation. The secondary side branch exhaust passage 2b is connected to the upstream side of the turbine Tp of the primary side branch exhaust passage 2a via the communication passage 12 on the upstream side of the exhaust cut valve 11. The communication portion 12 is connected to the branch exhaust passage 2b at a portion between the exhaust cut valve 11 and the turbine Ts via a bypass passage 14 in which an exhaust leakage valve 13 is arranged. 13 is the control pressure conduit
15 is operated by a diaphragm type actuator 16 which opens to the branch intake passage 3a on the downstream side of the blower Cp of the primary turbocharger 9, and in the process of increasing the engine speed, the downstream side of the blower Cp. Side boost pressure P1
Is equal to or greater than a predetermined value (for example, 500 mmHg), the valve is opened, whereby a small amount of exhaust gas is supplied to the turbine Ts through the bypass passage 14 when the exhaust cut valve 11 is closed. Therefore, the turbine Ts starts to rotate in advance before the exhaust cut valve 11 opens, and the torque shock when the exhaust cut valve 11 opens is reduced. Further, the communication passage 12 is connected to the exhaust passage 2 on the downstream side of both turbines Tp, Ts via a bypass passage 18 in which a waste gate valve 17 is arranged. Note that 19 and 20 are wire flam type actuators that operate the exhaust cut valve 11 and the waste gate valve 17, respectively. The operation of these actuators will be described later.

On the other hand, in the secondary side branch intake passage 3b, an intake cut valve 21 is disposed downstream of the blower Cs, and the blower Cs is further provided.
A passage 22 is provided for bypassing the bypass passage.
A relief valve 23 is provided at 22. Above intake cut valve
21 is operated by a diaphragm type actuator 24 so as to be opened and closed at the same time as the exhaust cut valve 11, and the relief valve 23 is a point at which the intake cut valve 21 and the exhaust cut valve 11 are opened in the process of increasing the engine speed. The bypass intake 22 between the blower Cs and the intake cut valve 21 is rotated by the rotation of the blower Cs based on the opening operation of the exhaust leakage valve 13 when the bypass passage 22 is opened slightly before and the exhaust cut valve 11 is closed. A diaphragm actuator 25 is provided to prevent the pressure in the passage 3b from rising and to facilitate the rotation of the blower Cs.
Is to be operated.

The control pressure conduit 26 of the actuator 24 that operates the intake cut valve 21 is connected to the output port of the three-way valve 27 that is an electromagnetic solenoid valve, and the control pressure conduit 28 of the actuator 19 that operates the exhaust cut valve 11 is the same. Is connected to the output port of a three-way valve 29 consisting of an electromagnetic solenoid valve. Furthermore, an actuator 25 that operates the relief valve 23
The control pressure conduit 30 is connected to the output port of the three-way valve 31 similar to the above, but only the control pressure conduit 32 of the actuator 20 that operates the wastegate valve 17 is the output of the two-way valve 33 that is an electromagnetic solenoid valve. Connected to a port. The three-way valves 27, 29, 31 and the two-way valve 33, which are electromagnetic solenoid valves, are controlled by a control circuit 35. The control circuit 35 controls the engine speed Ne, intake air amount Qa, throttle opening TVO and 1 Each electromagnetic solenoid valve is controlled based on the detection of the supercharging pressure P1 on the downstream side of the blower Cp of the secondary turbocharger 9.

Of the above four electromagnetic solenoid valves, one input port of the three-way valves 27, 29 is open to the atmosphere, and the other input port is connected to each other via a conduit 36, and the conduit 36 is connected to the throttle valve 6 of the throttle valve 6. The downstream intake negative pressure Pn is introduced via the check valve 37. Further, the conduit 36 is
It is connected to the output port of the differential pressure detection valve 39 via a conduit 38. One pressure detection port of the differential pressure detection valve 39 is connected to the downstream side of the intake cut valve 21 via a conduit 41, and
The supercharging pressure P1 on the downstream side of the secondary blower Cp is introduced, and the other pressure detection port is connected to the upstream side of the intake cut valve 21 via the conduit 42, and the intake cut valve 21 is The pressure P2 on the upstream side of the intake cut valve 21 when it is closed is introduced. When the pressure difference between the pressures P1 and P2 is large, the differential pressure detection valve 39 is in the open state and introduces the atmosphere into the conduits 39 and 37, but the differential pressure P2-P1 is a predetermined value ± Δ.
It is designed to close when it is within P. Therefore, when the differential pressure P2-P1 is larger than the predetermined value ± ΔP,
Regardless of the switching positions of the three-way valves 27 and 29, the atmosphere is introduced into the control pressure conduits 26 and 28 of the actuators 24 and 19, so that the intake cut valve 21 and the exhaust cut valve 11 are connected to the branch intake passage 3b and The branch exhaust passages 2b are closed, and only the turbocharger 9 on the primary side is operated. When the engine is running at low speed, the control circuit 35 controls the three-way valves 27 and 29 to open to the atmosphere side.Therefore, in this case as well, the intake cut valve 21 and the exhaust cutoff valve are irrespective of the value of the differential pressure P2-P1. Both valves 11 are closed.

On the other hand, when the supercharging pressure P1 rises and the differential pressure P2-P1 becomes within ± ΔP, the differential pressure detection valve 39 closes and the introduction of the atmosphere into the conduit 36 is blocked, and instead, the intake negative pressure enters the conduit 36. When the pressure Pn is introduced, the control circuit 35 controls the engine speed Ne and the intake air amount.
Since the intake negative pressure Pn is introduced to the actuators 24 and 19 by switching the three-way valves 27 and 29 based on the detection of Qa, the throttle opening TVO and the supercharging pressure P1, both the intake cut valve 21 and the exhaust cut valve 11 open. The secondary turbocharger 10 is activated. FIG. 3 shows the intake cut valve 21 and the exhaust cut valve.
A control map showing the open / closed state of 11 together with the open / closed states of the exhaust leakage valve 13, the waste gate valve 17, and the relief valve 23 is stored in the control circuit 35.

Further, one input port of the three-way valve 31 is also open to the atmosphere, and the other input port is connected to the conduit 36 via the check valve 43.When the engine is running at low speed, the intake negative pressure Pn is applied to the conduit 30. Since the relief valve 25 opens the bypass passage 22 because it has been introduced, as shown in FIG. 3, before the opening of the intake cut valve 21 and the exhaust cut valve 11 in the process of increasing the engine speed Ne. In the above, the three-way valve 31 is switched to the atmosphere side by the signal from the control circuit 35, whereby the relief valve 25 closes the bypass passage 22. Further, the supercharging pressure P1 is introduced into the input port of the two-way valve 33 through the control pressure conduit 15 of the actuator 16, and the engine speed Ne and the throttle opening VVO are equal to or higher than a predetermined value and the supercharging is performed. When the pressure P1 exceeds a predetermined value, the control circuit 35 opens the two-way valve 33 to introduce the supercharging pressure P1 to the actuator 20, whereby the waste gate valve 17 opens the bypass passage 18. .

In the above description, the configuration and the operation of the embodiment of the intake device for the engine with the exhaust turbocharger according to the present invention have been clarified, but according to this embodiment, the turbocharging of the primary side and the secondary side is performed. Since the passage portions of the branch intake passages 3a, 3b on the upstream side of the blowers Cp, Cs of the machines 9, 10 are formed so as to face each other, the pressure wave generated in the branch intake passage 3b when the intake cut valve 21 is opened and closed. It can be transmitted to the other branch intake passage 3a to be attenuated. Therefore, it is possible to prevent the air flow meter 4 from malfunctioning due to the pressure wave and prevent the torque fluctuation.

In addition, the turbochargers 9 and 10 on the primary side and the secondary side are
Since both blowers Cp and Cs are arranged so as to face each other outside, the passage length of the portion connecting the blower Cp and Cs of the branch intake passages 3a and 3b becomes long, which results in the intake cut valve.
The influence of the opening / closing operation of 21 on the blower Cp on the primary side is reduced, which also prevents the torque fluctuation of the engine 1.

By the way, in this embodiment, both turbochargers 9, 10 are
The bearings of the rotating shafts Lp and Ls of # 1 become extremely high in temperature, and particularly the temperature rise is remarkable in the bearing portion of the turbocharger 9 on the primary side that is operated in almost the entire operating region. Therefore, in this embodiment, as shown in FIG. 2, a cooling water passage 45 is provided for cooling the bearings of the rotating shafts Lp and Ls. In that case, since the circulation of the cooling water is also stopped when the engine 1 is stopped, the cooling water around the bearing portion of the primary turbocharger 9 having a higher temperature boils, and the bubbles pass through the cooling water passage 45. There is a possibility that it will rise and flow into the radiator. Therefore, in the present embodiment, the cooling water passage 45 is formed so that the cooling water passes through the primary side and secondary side turbochargers 9, 10 in series, and the primary side turbocharger 9 is connected to the secondary side. The turbocharger 10 is attached to the engine 1 so as to be slightly lower than the turbocharger 10, and the cooling water passage portion 45a connecting the turbochargers 9 and 10 is inclined. With such a configuration, when the engine 1 is stopped, the cooling water around the bearing portion of the primary turbocharger 10 rises in the cooling water passage portion 45a toward the secondary turbocharger 10 having a relatively low temperature. Therefore, there is an advantage that the boiling can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an embodiment of the present invention, FIG. 2 is a side view showing a configuration of a main part of a rotary piston engine embodying the present invention, and FIG. 3 is a control provided in its control circuit. It is a map. 1 ... Engine, 2 ... Exhaust passage 2a, 2b ... Branch exhaust passage 3 ... Intake passage 3a, 3b ... Branch intake passage 4 ... Air flow meter 9 ... Primary turbocharger 10 ... 2 Secondary turbocharger 11 …… Exhaust cut valve, 13 …… Exhaust leak valve 16, 19, 20, 24, 25 …… Diaphragm actuator 21 …… Intake cut valve 27, 29, 31 …… Three-way valve 33… Two-way valve, 35 Control circuit 39 Differential pressure detection valve, 45 Cooling channel

Continuation of front page (56) References JP-A-60-65238 (JP, A) JP-A-61-210224 (JP, A) Actually opened 62-200130 (JP, U) Actually opened 62-200129 (JP , U) Actual opening Sho 59-107929 (JP, U) Actual opening Sho 63-28834 (JP, U)

Claims (3)

(57) [Claims] 1. A turbine driven by exhaust gas,
Two exhaust turbochargers, which are provided on the rotating shaft of the turbine and are composed of a blower for supercharging the intake air, are provided, and the intake passage is branched and formed downstream of the air flow meter for detecting the intake air amount. Each of the two branch intake passages is provided with each of the blowers of the exhaust turbocharger, and a predetermined branch intake passage is provided with an opening / closing valve for opening and closing the branch intake passage according to the operating state. In the intake system of the engine, the two exhaust turbochargers are arranged so as to face each other in a manner that both blowers are located outside, and the upstream intake passage parts of both blowers are formed to face each other, An intake device for an engine with an exhaust turbocharger, wherein the branch intake passage portions facing each other are arranged so as to pass above the two exhaust turbochargers. 2. A turbine driven by exhaust gas,
Two exhaust turbochargers, which are provided on the rotating shaft of the turbine and are composed of a blower for supercharging the intake air, are provided, and the intake passage is branched and formed downstream of the air flow meter for detecting the intake air amount. Each of the two branch intake passages is provided with each of the blowers of the exhaust turbocharger, and a predetermined branch intake passage is provided with an opening / closing valve for opening and closing the branch intake passage according to the operating state. In the engine intake system, the two exhaust turbochargers are arranged so as to face each other such that both blowers are located outside, and the branch intake passage portions on the upstream side of both blowers are connected to each other. Arranged so that the central axis is substantially straight, and that the central axis forms a predetermined angle with respect to the central axis of the intake passage in the branch portion of the intake passage provided with the air flow meter. Further, an intake system for an engine with an exhaust turbocharger, characterized in that a branch intake passage portion whose central axis is substantially straight is arranged so as to pass above the two exhaust turbochargers. 3. A turbine driven by exhaust gas,
Two exhaust turbochargers, which are provided on the rotating shaft of the turbine and are composed of a blower for supercharging the intake air, are provided, and the intake passage is branched and formed downstream of the air flow meter for detecting the intake air amount. Each of the two branch intake passages is provided with each blower of the exhaust turbocharger, and the intake system and the exhaust system provided with one exhaust turbocharger are opened in a predetermined operating range. In an intake system for an engine provided with an intake cut valve and an exhaust cut valve, both of the two exhaust turbochargers are located inside and both blowers are located outside. The turbocharger is arranged laterally of the engine so that the rotary shafts thereof are in series with each other, and the upstream branch intake passage portions of both blowers are formed so as to face each other and face each other. An intake system for an engine with an exhaust turbocharger, characterized in that a branch intake passage portion is arranged so as to pass above the two exhaust turbochargers.