RU2559207C1 - Turbine compressor for boosting of internal combustion engines - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention can be used in combined internal combustion engines with controlled boosting. The turbine compressor for boosting of internal combustion engines comprises the turbine housing (3), the turbine wheel (1), the nozzle rim (2), the turbine insert (4), the compressor housing (10), the compressor insert (16), and at least one executive mechanism (9) with the lever (8). The turbine is also fitted with the rotary bushing (5) axially fixed by the thrust ring (7). The side surface of the rotary bushing (5) has a row of holes (6) aligned with holes in the turbine insert (4) turbines and oriented at an angle to the turbine compressor rotor axis. The insert (16) is installed in the compressor which forms the bypass. On the side surface of the compressor housing (10) the holes are made (15). The suction branch pipe of the housing has the check valve (14) for air bypass around the compressor at emergence of pressure difference between suction (12) and injection (13) cavities.

EFFECT: improvement of reliability of turbine compressor.

1 dwg

Description

The present invention relates to mechanical engineering, in particular to engine building, namely to combined internal combustion engines with adjustable supercharging.

Supercharging is the most effective way to increase the effective engine power while improving efficiency in nominal and close modes.

Nevertheless, the use of gas turbine pressurization, along with the advantages, has a number of significant drawbacks, the main of which is a decrease in engine efficiency at partial load conditions up to 70-80% (and in some cases more) of the rated power of the boost engine. In addition, when the ambient temperature decreases, the density of air charge entering the engine cylinders increases, which leads to an increase in the mass filling of the cylinders with air and an improvement in the combustion process. In this regard, the zone of economical operation of the engine with the turbocharger off is shifted towards high loads. For example, when testing the SMD-62 engine with and without a turbocharger at ambient temperature (OS) minus 33 ° C, the naturally aspirated engine had higher efficiency compared to a supercharged engine with a load of up to 93% of the nominal.

The decrease in the efficiency of a diesel engine at partial loads is explained by the fact that the power developed by the turbine and spent on the compressor is provided by part of the energy of the exhaust gases and part of the effective power of the engine, which is spent on overcoming the resistance during the forced expulsion of gases from the cylinders. Thus, part of the effective engine power is spent on the turbocharger drive, which provides the supply of excess air to the engine cylinders.

Given that most of the time tractors, performing agricultural operations, operate in partial modes, the creation of simple and reliable devices that could combine the advantages of naturally aspirated engines with supercharged engines is very important for machine builders and consumers.

Currently, the most widespread devices are those that transfer gases past the turbine, and in some cases, air past the compressor.

Known adjustable ejector, with which you can change the flow rate of exhaust gases entering the turbine drive (Japanese application No. 60-22024, STRUCTURE OF VARIABLE EJECTOR IN EXHAUST TURBINE, CL F02B 37/12, 1986;).

In a known solution, the flow part of the turbine has a main and additional gas channels. As a regulatory element, a movable nozzle of variable geometry was used. The nozzle may open or close an additional channel. When the auxiliary channel is closed, the entire mass of exhaust gas passes through the flow part of the turbine. When the nozzle ring moves along the axis of the turbocharger, the additional channel opens, and the exhaust gases pass through the additional channel directly into the exhaust pipe, bypassing the turbine flow section.

The disadvantages of the device:

1. The large volume of the bypass channel does not allow the full use of the energy of the pressure pulses of the exhaust gases generated at the time of opening the exhaust valves, which significantly impairs the performance of the engine in all modes.

2. With the reciprocating movement of the nozzle ring, it becomes possible to jam the mating surfaces, which can contribute to soot formed on the surface of the turbine flow path.

3. There is no possibility of supplying air to the engine, bypassing the compressor, when the latter is the resistance on the suction line.

A device is also known that allows you to change the amount of exhaust gas entering the turbine drive using a movable control insert to increase the turbocharger power for a short time (Patent No .: US 6,715,288 B1; Controllable exhaust gas turbocharger with a double-fluted turbine housing; Date of Patent : Apr. 6, 2004).

The device consists of a turbine housing, a turbine wheel, a main channel, an additional channel, and a movable control insert. This device operates as follows. In forced mode, the control insert is in the leftmost position, blocking the additional channel. Exhaust gases enter the turbine impeller only from the main channel at maximum speed. When the engine is partially loaded, the insert moves to the middle position, opening both channels. If it is necessary to turn off the turbocharger, the insert is moved to a position farthest from the rotor, and the gases freely pass into the exhaust pipe through an additional channel and the resulting gap.

The disadvantages of the device:

1. The large volume of the bypass channel does not allow the full use of the energy of the pressure pulses of the exhaust gases generated at the time of opening the exhaust valves, which significantly impairs the performance of the engine in all modes.

2. With the reciprocating movement of the movable insert, it becomes possible to jam mating surfaces, which can contribute to soot formed on the surface of the turbine flow path.

3. There is no possibility of supplying air to the engine, bypassing the compressor, when the latter is the resistance on the suction line.

The closest technical solution adopted for the prototype is a device that is designed to reduce the heating time of the catalyst of the internal combustion engine by passing the exhaust gases past the turbine duct and simultaneously bypassing air bypassing the compressor (EP 1219799 A2; Exhaust gas turbine for internal combustion engine and exhaust turbo-supercharger; Date of publication July 3, 2002; Hitachi, Ltd.).

Air bypass is necessary, because with an idle turbine, excessive resistance is created on the suction line. The device comprises a turbocompressor, a channel for passing exhaust gases past the turbine, a bypass valve that is controlled by an actuator, a movable insert that serves to bypass the compressor, moving along the axis of the turbocompressor shaft, and an actuator.

This device operates as follows. During start-up and after-start warm-up, the bypass valve opens and the exhaust gases are sent to the catalyst, bypassing the turbine. Thus, the heating time of the catalyst is reduced compared with systems without gas bypass. To reduce air resistance on the suction line, the movable insert moves to the leftmost position, increasing the gap between the compressor wheel and its body.

Design disadvantages:

1. The large volume of the bypass channel does not allow the full use of the energy of the pressure pulses of the exhaust gases generated at the time of opening the exhaust valves, which significantly degrades the performance of the turbocharger and, accordingly, the engine in all modes.

2. The presence of valves complicates the design of the turbocharger and, as a result, increases aerodynamic losses and reduces the reliability of the device.

An object of the invention is to increase the fuel efficiency of the engine and the reliability of the adjustable turbocharger. The problem is solved by partially or completely shutting off the turbocharger when the engine is idling, partial modes and nominal mode, when the charge air pressure is excessive or does not correspond to the optimal value.

The essence of the invention lies in the fact that the turbocharger has profiled bypass channels for communicating high and low pressure zones. When the engine is idling and partial loads, the turbocharger operates in the “Turbocharger off” mode. In this case, the exhaust gases are divided into two streams: the part goes through the bypass channels and then into the exhaust pipe, the other part passes through the nozzle apparatus of the turbine. Bypass channels - a series of matching holes made in the casing of the flow part of the turbine and the rotary sleeve. Moreover, the holes are made at an angle to the axis of the rotor of the turbocompressor, which helps to reduce the back pressure of the rotating rotor due to the effect of ejection of exhaust gases. When moving the rotary sleeve at a certain angle, the holes located on the surface of the casing of the flow part of the turbine overlap with the side surface of the sleeve. The turbocharger switches to the “Turbocharger is on” mode. The bore of the main channel remains constant at any position of the rotary sleeve.

This design solution allows the engine to idle and partial loads to support the operation of the turbocharger in the "hot" mode. "Hot" mode - the operation of a turbocharger with free exhaust through the bypass channels. The rotation of the rotor of the turbocompressor in this case is mainly due to the waste energy of the exhaust gases (pulse energy). According to the available experimental data, the rotor speed of the turbocompressor in this case, for example, for the SMD-62 engine can be in the range of 8-22 thousand min ^-1 . This effect reduces the acceleration time of the turbocharger rotor during transient conditions, for example, with a sharp increase in load characteristic of tractor diesels. In addition, the operation of the turbocharger in the "hot" mode without backpressure in the exhaust manifold contributes to a certain reduction in engine power spent on pumping strokes, causing an additional increase in its economy. To eliminate possible air “starvation” of the engine during the start-up period or a sharp increase in load, air is supplied to the engine air collector from the atmosphere through a non-return air valve and, partially, through the flow part of the compressor. The valve can be placed in the air manifold or integrated into the compressor design. For this purpose, a bypass channel is provided in the compressor connecting the air discharge and intake zones. An elastic check valve made of heat-resistant rubber or other elastic and heat-resistant material is installed in the channel, blocking the bypass channel when the compressor creates pressure in the air manifold.

The authors and the applicant are not aware of technical solutions that would use the distinguishing features of the proposed solution. The proposed design of the turbocharger, as shown by tests, has high reliability and provides regulation in a wide range of turbine throughput, up to its complete shutdown.

In addition, this design allows to reduce the dimensions of the device, to avoid jamming of the rotary sleeve at high exhaust gas temperatures, to reduce backpressure when the bypass channel is fully open.

The drawing shows the proposed turbocharger. The turbocharger includes a turbine wheel 1, a nozzle crown 2, a turbine housing 3, a turbine insert 4, a rotary sleeve 5, gas bypass holes 6, a thrust ring 7, a lever 8, an actuator 9, a compressor housing 10, an air bypass channel 11, a cavity suction 12, discharge cavity 13, check valve 14, air bypass holes 15, compressor insert 16.

A rotary sleeve 5 is mounted in the turbine housing 3, which is held from axial movement by means of a thrust ring 7. A number of holes 6 are made on the cylindrical surface of the turbine insert 4 and the rotary sleeve 5, connecting the high and low pressure zones of the turbine. Moreover, the axis of the holes forming the bypass channels are oriented in the direction of gas movement in the exhaust path of the turbine.

On the side surface of the compressor housing 10, holes 15 are made for air bypass, connecting the discharge cavity 13 and the compressor suction 12. The bypass channel 11 is located between the end walls of the compressor housing 10 and the compressor insert 16. The check valve 14 is installed on the suction pipe of the compressor housing 10.

The turbocharger operates as follows. When the hole 6 on the cylindrical surface of the insert 4 is blocked by the lateral surface of the rotary sleeve 5, the exhaust gases flowing into the snail housing 3 of the turbine pass through the nozzle ring 2 and fall on the blades of the turbine wheel 1. Due to the energy of the exhaust gases, the turbine wheel 1 starts to rotate the compressor wheel rotates with it. Air is compressed by the compressor and supplied to the engine.

Due to the pressure difference in the discharge cavity 13 and the suction 12, the bypass channel 11 is blocked by a check valve 14. The turbocharger operates in the “turbocharger is on” mode.

When the rotary sleeve 5 is moved by the actuator 9 through the lever 8 to a certain angle, the bypass holes 6 in the turbine insert 4 and the rotary sleeve 5 coincide, the turbocharger switches to the “turbocharger off” mode. The exhaust gases in this mode go in two flows: part of the gas goes through the nozzle apparatus of the turbine, and the second part goes through the bypass channels.

Since the bypass channels are oriented in the direction of gas movement, an ejection effect is created in the exhaust channel of the turbine, which increases the efficiency of the turbine due to more complete use of the energy of the exhaust gases. In addition, the bypass value can be controlled by changing the angle of rotation of the rotary sleeve 5 with respect to the insert 4 using the actuator 9 and, thereby, the passage section of the bypass channels. The actuator may be hydraulic, pneumatic, or electric.

The operation of the turbine in this mode is carried out mainly due to the energy of pressure pulses that occur in the exhaust tract that occur when the exhaust valve opens. For this reason, the air supply to the compressor decreases, as a result of which a vacuum is created in the discharge cavity 13 of the compressor due to the suction action of the engine pistons, the check valve 14 opens the bypass channel 11 and air is supplied to the engine directly from the atmosphere, bypassing the compressor.

Thus, the use of a regulating element in the form of a rotary sleeve allows to improve the working conditions of the mating surfaces and to eliminate the possibility of their jamming, and the bypass channels connecting the discharge and suction zones in the compressor housing, and their overlapping by a check valve, reduce the dimensions of the device and increase the reliability of the design regulatory systems.

Claims (1)

Turbocharger for boosting internal combustion engines, comprising a turbine housing, a turbine wheel, a nozzle rim, a turbine insert, a compressor housing, a compressor insert, at least one actuator with a lever, characterized in that the turbine is further provided with a rotary sleeve that is held against axial movement by a thrust ring , on the side surface of which a series of holes are made, coinciding with the holes in the turbine insert and directed at an angle to the axis of the turbocompressor rotor; an insert is additionally installed in the compressor, which forms a bypass channel, in addition, holes are made on the side surface of the compressor casing, and a check valve is installed on the suction pipe of the casing for air bypassing the compressor in case of a pressure differential between the suction and discharge cavities.