JP2004530833A - Turbocharger for two-stroke diesel engine - Google Patents

Abstract

At least one turbocharger (1) driven by exhaust gas from the engine for supplying supercharged scavenging air to the engine; and a turbocharger for reducing the temperature of the scavenging air. At least one air cooler (2) located downstream, and a centrifugal blower for supplying additional scavenging air and scavenging air pressure to the engine if the load is reduced to a predetermined value during operation. Turbocharger, in particular for a two-stroke diesel engine, comprising at least one auxiliary blower (4) designed as (4). The inlet of at least one centrifugal blower (4) is connected to the outlet of at least one intercooler (2), while the outlet is connected to the scavenging air container of the engine. This turbocharger utilizes a centrifugal blower that is already part of the device. This provides a simple and inexpensive structure that can effectively remove condensed water from the supercharged and cooled scavenging air supplied to the operating diesel engine.

Description

【Technical field】
[0001]
The present invention provides at least one turbocharger driven by exhaust gas from an engine for supplying supercharged scavenging air to an engine, and at least one turbocharger for reducing the temperature of the scavenging air. At least one intercooler located downstream of the supercharger, and a centrifugal blower for supplying additional scavenging air and scavenging air pressure to the engine when the load drops to a predetermined value during operation. In particular for a two-stroke diesel engine, comprising at least one auxiliary blower designed as:
[Background Art]
[0002]
The natural moisture in the supercharged scavenging air will condense more or less to some extent when the air is cooled on its way through the intercooler.
[0003]
This condensed water can cause serious damage to the sleeve and piston ring if taken into the engine cylinder with scavenging air. Therefore, water is usually separated beforehand.
[0004]
From U.S. Pat. No. 6,059,086 a water separator for removing water drops from a stream of compressed and cooled scavenging air, for example for a two-stroke diesel engine, is known.
[Patent Document 1]
German Patent No. 19,911,252
This known water separator mainly consists of a cyclone section having a lower drain chamber for catching and releasing water droplets. The water droplets are thrown against the curved inner surface of the cyclone while the scavenging air passes. Although useful, water separators complicate the structure of the turbocharger and increase the cost of manufacturing individual engines.
DISCLOSURE OF THE INVENTION
[Problems to be solved by the invention]
[0006]
It is a first object of the present invention to provide a turbocharger of a simple and inexpensive construction, of the kind mentioned in the opening paragraph.
[0007]
It is a second object of the present invention to provide a turbocharger of the kind mentioned in the opening paragraph, which mainly employs engine elements already forming part of this device.
[0008]
A third object of the present invention is to provide a scavenging air supplied to a supercharged and cooled diesel engine, for example a two-stroke diesel engine, of the kind mentioned in the opening paragraph, in a manner known from the heretofore known approaches. Another object of the present invention is to provide a turbocharger capable of removing condensed water more effectively.
[Means for Solving the Problems]
[0009]
A novel and unique feature of the present invention (which realizes the invention) is that the inlet of at least one centrifugal blower is connected to the outlet of at least one intercooler, while the blower itself Is to be connected to a scavenging air container which is part of the engine.
[0010]
Turbochargers typically include at least one supercharger driven by exhaust gas from an engine passing through a turbine, and at least one intercooler for cooling the supercharged scavenging air to a suitable temperature. I have.
[0011]
In addition, turbochargers usually include one or more centrifugal auxiliary blowers. The auxiliary blower is positively interposed to compensate for a decrease in the turbocharging effect when the engine load is reduced.
[0012]
At the same time, these centrifugal blowers are connected in parallel to several check valves. These check valves are arranged with a sufficiently large flow area so that the turbocharger can be operated at full power while the centrifugal blower is inactive during a heavy load.
[0013]
According to the invention, these centrifugal blowers are also used here as water separators. The scavenging air is forced to flow through the blower during operation, both at high and low loads.
[0014]
This has the considerable advantage that the costs for conventionally used water separators and check valves are eliminated.
[0015]
Moreover, the ability of the centrifugal blower to remove condensed water from the compressed and cooled scavenging air is further improved over conventional water separators.
[0016]
This is mainly due to the fact that the centrifugal blower functions by means of a rotating impeller, as opposed to a cyclone. This rotary impeller generates an effective centrifugal force to centrifuge the condensed water from the scavenging air and throws it onto the curved inner surface of the blower. Thus, while the dry scavenging air is blown into the cylinder of the engine, water is removed from the blower.
[0017]
To promote this advantageous effect, the individual auxiliary impellers are constantly rotating during operation, so that the auxiliary impellers are driven by electric motors in situations below a preset light load level. The auxiliary impeller is driven by the airflow generated by the internal combustion engine / turbocharger in situations where the scavenging air pressure of the internal combustion engine / turbocharger is sufficiently high and exceeds this level.
[0018]
As mentioned above, the invention is based on the finding that all of the scavenging air always passes through a centrifugal blower used as an auxiliary blower. In other words, these centrifugal blowers must be designed to allow a greater amount of scavenging air to pass through more efficiently.
[0019]
Therefore, the centrifugal blower employed must be dimensioned differently than the auxiliary blower. This auxiliary blower makes it possible to meet the general requirements for a blower in such a turbocharger, whereby it has a minimum flow area at full load, with a maximum scavenging air velocity of about 50 m / s. Therefore, it is conventionally used.
[0020]
According to the invention, the centrifugal blowers can be arranged in various ways, for example with a horizontal, vertical or oblique rotation axis.
[0021]
However, in an advantageous embodiment, the individual centrifugal blowers are arranged to have at least a predominantly horizontal axis of rotation.
[0022]
According to the invention, the drain chamber can be provided at the bottom of the housing in each centrifugal blower. The chamber has a slit directed to a direction opposite to the flow direction of the scavenging air for guiding separated condensed water into the chamber, and an outlet for guiding trapped condensed water out of the chamber. .
[0023]
The separated condensed water tends to flow along the curved inner surface of the blower housing toward the blower outlet. During this time, the separated condensed water flows into the drain chamber through a slit directed in a direction opposite to the flow direction of the scavenging air.
[0024]
To ensure that any condensed water that has passed through the drain chamber is also trapped and removed from the blower, the perforated plate must be run from the blow chamber drain chamber to its outlet or along the part of the blower that extends toward the outlet. It can be installed slightly away from the curved outer wall. The plate, together with the outer wall, forms a drain passage leading into the drain chamber.
[0025]
Under the influence of the passing air flow, condensed water that has not yet been trapped by the drain chamber is now forced through the opening in the perforated plate into the drain path. Thereafter, the condensed water flows down this path by the action of gravity and enters a drain chamber provided below.
[0026]
It is advantageous to provide the drain path with a flow resistor to reduce the occurrence of the opposite air flow in the drain path, which may counteract the effect of gravity on the condensed water in the drain path. . The resistor comprises, for example, a mesh wiring inserted into the road.
[0027]
Further, between the two drain passages, a first section into which condensed water flows from a slit facing in the direction opposite to the flow direction and a second section into which condensed water flows from the slit facing in the flow direction. Partitions can be set up. By directing the separated condensed water out of the individual drain chamber sections via their own outlets, the two opposite flows of condensed water are effectively separated in the drain chamber. It becomes. And the air flow cannot resist the effect of gravity acting on the condensed water.
[0028]
As can be seen, the turbocharger according to the invention is capable of efficiently removing condensed water from supercharged and cooled scavenging air, for example supplied to a running two-stroke diesel engine.
[0029]
If an independent water separator is additionally interposed at the connection between the inlet of the centrifugal blower and the outlet of the intercooler, condensed water may enter the cylinders of the individual engines together with the scavenging air if a separate water separator is inserted. , Further safety is obtained.
BEST MODE FOR CARRYING OUT THE INVENTION
[0030]
Hereinafter, the present invention will be described in more detail with reference to the drawings and referring only to typical embodiments.
[0031]
The following example assumes that the turbocharger according to the invention is used in a two-stroke diesel engine.
[0032]
The turbocharger schematically illustrated in FIG. 1 is driven by the exhaust gas from a two-stroke diesel engine and functions to supercharge the scavenging air supplied to its cylinder (not shown), Some turbochargers 1, some intercoolers 2 for reducing the temperature of the scavenging air, some receivers 3 connecting the intercoolers 2 to one or more centrifugal blowers 4, and a pressurized state And a scavenging air container 5 designed to contain a suitable amount of scavenging air and connected to a cylinder of the engine. The centrifugal blower 4 functions to supply scavenging air from the turbocharger 1 during operation and to supply additional scavenging air and scavenging air pressure to the engine due to a reduction in engine load.
[0033]
FIG. 2 is a side view of a part of the turbocharger of FIG. As shown, the device of this example comprises two receivers 3, each connected to two centrifugal blowers 4. This centrifugal blower 4 is also connected to a scavenging air container 5.
[0034]
A first embodiment of the turbocharger of FIGS. 1 and 2 is shown schematically in FIG. Similar parts are indicated by the same reference numerals.
[0035]
In the example shown, there are two independent auxiliary blowers capable of supplying scavenging air to the engine. This provides great operational reliability, as one device allows the engine to continue running even if the second device does not operate properly or to some extent.
[0036]
During operation, the turbocharger 1 generates supercharged scavenging air supplied to the intercooler 2 via the air duct 6. The two air ducts 6 are connected to each other by an air distribution duct 7. This allows the system to function even if one of the auxiliary blowers does not work properly. Alternatively, the air distribution duct 7 can be arranged after the intercooler 2. In this case, the scavenging air is now cooled.
[0037]
The inlet 9 of the centrifugal blower 4 is connected to the outlet 10 of the intercooler 2 via the other two air ducts 8. A valve 11, interposed in each of the two air ducts 8, for example of the "butterfly" type, is provided with scavenging air in individual parts of the blower device if desired if the blower is not operating. Help to cut off recirculation.
[0038]
The supercharged scavenging air cooled while passing through the intercooler 2 flows into the centrifugal blower 4 through the two air ducts 8. Thereafter, the scavenging air is guided by a powerful rotation from the centrifugal blower to its outlet 12.
[0039]
Via two additional air ducts 13, the scavenging air is finally led to the scavenging air container 5. Thereby, the scavenging air container 5 is filled with an appropriate amount of supercharged and cooled scavenging air. This scavenging air is supplied to a cylinder (not shown) of a two-stroke diesel engine during startup and operation.
[0040]
Natural moisture in the supercharged scavenging air leaving the turbocharger 1 condenses, at least to some extent, while the scavenging air passes through the intercooler.
[0041]
However, condensed water does not reach the cylinders of the engine, where it can especially damage the sleeve and piston ring. According to the present invention, condensed water is therefore removed during the passage of the scavenging air through each of the two centrifugal blowers via the drain chamber 24. The condensed water thus captured is released through the water duct 16a. Therefore, important functions will be described in detail later.
[0042]
FIG. 4 is a schematic diagram of another embodiment of the turbocharger of FIG. Similar parts are indicated by the same reference numerals.
[0043]
In this example, an independent water separator 14 is on the other hand interposed in each of the two other ducts 8. The separator is designed as a cyclone in a self-evident manner. While the supercharged and cooled scavenging air passes through this cyclone section, the condensed water content in the air is affected by the centrifugal force that casts condensed water on the curved walls of the cyclone section. Here, the condensed water is captured by the second drain chamber 15 provided below the cyclone unit. The captured condensed water is guided from the drain chamber to the outside of the water separator 14 via the second water duct 16b.
[0044]
The independent water separator 14 of FIG. 4 functions to increase the certainty of removing condensed water from the supercharged and cooled scavenging air generated by the turbocharger.
[0045]
However, the main effect is obtained by the centrifugal blower 4 according to the present invention in both the first embodiment of FIG. 3 and the second embodiment of FIG. 4, as described in detail below with reference to FIGS. Can be
[0046]
FIG. 5 is a cross section through the centrifugal blower 4. It mainly consists of a blower housing 17 having an impeller 18 in the form of a number of rearwardly facing blades 20 mounted on a shaft 19. During operation, the impeller rotates in the direction indicated by the arrow.
[0047]
The impeller has an inlet 9 and an outlet 12. The air that has entered through the inlet 9 is turned at a high speed during operation by the rotation of the impeller 18. Then, during this time, it is guided to the outlet 12 of the blower housing by its curved wall 23, which can be, for example, involute.
[0048]
In the example shown, the centrifugal blower has a horizontal rotation axis. A drain chamber 24 is provided at the bottom of the housing, and a perforated plate 25 is installed above the chamber at a relatively short distance from the curved wall 23. The plate is designed with a number of openings 26 and extends towards or to the outlet 12 of the blower housing.
[0049]
The perforated plate 25 and the curved wall 23 of the blower housing form a drain channel 27. A mesh 28, a part of which is shown in FIG.
[0050]
The drain chamber 24 is divided by a partition 29 into a first section 30 and a second section 31. The first section 30 communicates with the interior of the blower housing 17 via a slit 32 oriented in the dominant flow direction in the blower housing. Further, the baffle plate 33 is further set slightly away from the slit 32. Drain path 27 leads to second section 31.
[0051]
In the two sections 30, 31 of the drain chamber 24 there are first and second outlets 34, 35 respectively. This serves to guide the captured condensed water from the room to the outside, as indicated by arrows.
[0052]
As can be seen, the turbocharger is designed so that all scavenging air is always forced through the centrifugal blower 4. Each of the centrifugal blowers 4 is driven by the blower under normal or full load conditions and, at a predetermined reduced main engine load, is configured to drive the blower with an electric motor (not shown in FIG. 5) or Connected to a similar motor. Alternatively, each centrifugal blower can be connected to its motor by a coupling to connect or disconnect the respective connection.
[0053]
This configuration provides additional scavenging air and scavenging for the engine at predetermined light loads, even though the impeller is passively rotated by scavenging air generated by the turbocharger when the load is large. As an auxiliary blower for supplying air pressure, this results in the fact that a centrifugal blower can be activated actively.
[0054]
The blower vehicle is therefore constantly rotating during operation, for example at a rotational speed of at least 500 rpm. During this time, the water droplets contained in the scavenging air shown in FIG. 5 are effectively thrown against the curved walls 23 and 25 of the blower housing 17.
[0055]
The droplet 36 collides with the curved walls 23, 25 with a velocity component towards the outlet of the blower housing. Further, the droplets 36 are driven in the same direction by the flow action of the scavenging air passing through the blower.
[0056]
During this time, a part of the condensed water thus moving along the curved walls 23, 25 of the blower housing 17 in the direction of the outlet of the blower housing passes through the slit 32 to the first section of the drain chamber 24. Guided inside 30. There, a part of the condensed water is guided downward by the baffle 33 through the first outlet 34 of the drain chamber and out of the blower.
[0057]
Condensed water that could not be captured by the first section of the drain chamber continues to travel towards the outlet of the blower housing, but here over the perforated plate 25. During this time, condensed water is forced into the drain channel 27 by centrifugal force and scavenging air passing through the aperture 26 in the perforated plate. This drain channel 27 guides the condensed water that has been trapped to a second section 31 provided at the bottom of the drain chamber. Condensed water is removed from the drain chamber via a second outlet 35.
[0058]
A second drain passage 37 located at the start of the curved wall 23 of the blower housing serves to trap condensed water running down the wall at this point. The trapped condensate flows down the side walls of the blower housing towards the curved walls 23, 25 of the housing. The condensed water thus trapped is discharged out of the blower housing as described above.
[0059]
FIG. 1 shows a more specific configuration of the turbocharger of FIG. Here, the intermediate chamber 3 functions as a cyclone unit similar to the water separator 14 having the outlet 16b. In addition, two outlets 34, 35 of the centrifugal blower are shown.
[Brief description of the drawings]
[0060]
FIG. 1 is a schematic end view of a turbocharger according to the present invention.
FIG. 2 is a detailed side view of the turbocharger of FIG.
FIG. 3 is a diagram of a first embodiment of the turbocharger of FIGS. 1 and 2;
FIG. 4 is a diagram for a second embodiment of the turbocharger of FIGS. 1 and 2;
FIG. 5 is an enlarged sectional view of a blower for the apparatus of FIGS. 3 and 4;
FIG. 6 is an enlarged partial view of the curved wall of the centrifugal blower of FIG.
[Explanation of symbols]
[0061]
DESCRIPTION OF SYMBOLS 1 Turbocharger 2 Intercooler 3 Receiver 4 Centrifugal blower 5 Scavenging air container 6, 8, 13 Air duct 7 Air distribution duct 9 Inlet 10, 12 Outlet 11 Valve 14 Water separator 15 Second drain room 16a Water duct 16b Second water duct 17 Blower housing 18 Impeller 19 Axis 20 Backward blade 23 Curved wall 24 Drain chamber 25 Perforated plate 26 Opening 27 Drain path 28 Mesh 29 Partition 30 First section 31 Second section 32 Slit (introduction opening )
33 baffle plate 34 first discharge port 35 second discharge port 36 drop 37 second drain path

Claims (10)

At least one turbocharger (1) driven by exhaust gas from the engine for supplying supercharged scavenging air to the engine;
At least one intercooler (2) arranged downstream of the at least one turbocharger (1) for reducing the temperature of the scavenging air;
At least one auxiliary blower (4) designed as a centrifugal blower (4) for supplying additional scavenging air and scavenging air pressure to the engine if the load decreases to a predetermined value during operation. ) And
The inlet (9) of the centrifugal blower (4) is connected to the outlet of the at least one intercooler (2), while the outlet (12) of the blower itself is connected to the scavenging air of the engine. A turbocharger, particularly for a two-stroke diesel engine, which is connected to a container. The drain chamber (24) having at least one inlet opening (32) for guiding condensed water separated from the cooled scavenging air flowing into the drain chamber (24) via the centrifugal blower (4). When,
At least one outlet (34; 35) for guiding trapped condensed water from said drain chamber;
The turbocharger according to claim 1, wherein the turbocharger is provided at a lower portion of a blower housing (17) of the at least one centrifugal blower (4). 3. The turbocharger according to claim 2, wherein the impeller (18) of the at least one centrifugal blower (4) has a predominantly horizontal axis of rotation. At least one inlet opening (32) for guiding condensed water to a drain chamber (24) of the at least one centrifugal blower has at least one inlet opening directed in a dominant flow direction in the centrifugal blower (4). 4. The turbocharger according to claim 2, wherein the turbocharger comprises two mainly slit-shaped openings. A perforated plate (25) extends from the drain chamber (24) of the centrifugal blower (4) to its outlet (12) or along a portion extending toward the outlet (12). It is installed slightly away from the curved outer wall (23) of the centrifugal blower (4),
5. The device according to claim 2, wherein the plate, together with an outer wall, forms a drain passage leading into the drain chamber. 6. 3. The turbocharger according to 1. The turbocharger according to claim 5, wherein the drain path (27) is designed to have at least one flow resistor (28). The turbocharger according to claim 6, wherein the flow resistor of the drain passage (27) is formed of a mesh (28) inserted in the drain passage. A partition (29) is inserted into the drain chamber (24),
The partition (29) defines the drain chamber (24),
A first section (30) whose at least one flow direction is directed toward said slit-shaped opening (32);
Divided into a second section (31) with an outlet for the drain passage (27) in the drain chamber (24);
6. Each of these two sections (30; 31) has, besides the individual sections, at least one outlet (34; 35) for guiding trapped condensed water. The turbocharger according to any one of claims 6 to 7. An independent water separator is interposed at the connection between the inlet (9) of the at least one centrifugal blower (4) and the outlet (12) of the at least one intercooler. The turbocharger according to any one of claims 1 to 8, wherein: The at least one centrifugal blower (4) is configured to rotate the centrifugal blower at a predetermined reduction in engine load and to be rotated by the centrifugal blower at a smaller predetermined reduction. The turbocharger according to any one of claims 1 to 9, wherein the turbocharger is connected to a motor.