RU2301899C1 - Method of and device to control gas exchange in turbocharged diesel engine - Google Patents

Abstract

FIELD: mechanical engineering; turbocharged diesel engines.

SUBSTANCE: proposed method to control gas exchange in turbocharged diesel engine includes bypass control of turbine of turbocompressor, cooling of supercharging air, recirculation into cylinder and ejection of exhaust gases. Smaller part is separated from full flow full flow of exhaust gases at outlet of exhaust manifold and is directed, bypassing the turbine at idling and low load, into cylinders for recirculation, and at mean and rated loads, into atmosphere, and at overloads, together with larger part of exhaust gases, into turbine. At mean and rated loads smaller part of flow is directed to ejector. At overloads, full flow of exhaust gases after turbine of turbocompressor is directed to ejector. Device to control gas exchange in turbocharged diesel engine contains spool mechanism with cylindrical housing in which three channels are, two of which are arranged opposite to third one, and axis of the latter is between axes of two first channels, and control member with two pistons connected by rod. Two channels are made additionally in housing, one being arranged in end face of housing and its axis coincides with axis of housing, and other channel being arranged on generatrices of housing and its axis is square to axis of housing.

EFFECT: provision of combination of functions of ejection cooling of supercharging air and bypass control of turbine of turbocompressor.

5 cl, 4 dwg

Description

The invention relates to the field of engine building and is intended for use in a gas turbine diesel engine containing charge air cooling, bypass regulation of the turbine, recirculation to the cylinder and ejection of exhaust gases.

A known method of operation of a diesel engine with gas turbine pressurization and autonomous use of bypass control of a turbine of a turbocharger and recirculation of a part of the exhaust gas stream into a cylinder (Dieselradialkolben-Verteilerinspritzpumpen VR. Technische Unterrichtung. 2. Ausgabe. U. Reuter, F. Eichhom, J. Mossinger and. : Robert Bosch GmbH. - 1998. - 25 s.). At the same time, autonomous devices were used, each of which solves one of the problems: exhaust gas recirculation or bypass regulation of the turbine. The use of two stand-alone devices significantly complicates their drive system. In this case, it is required to have a separate drive to each device.

A known method of operating a naturally aspirated diesel engine by using ejection of exhaust gases to circulate ambient air through a radiator of a liquid cooling system (DET-250 tractor and its modifications. Edited by A.S. Pisarevsky. Ed.2-e, revised and additional - M .: Engineering. - 1975 .- 424 p.). It is also known a device for implementing this method of operation, containing an ejector, a mixing chamber and a system of gas and air pipes. The main disadvantage of this method and device for its implementation is the use of a full stream of exhaust gases for the implementation of the ejection process, including at idle, low and medium loads. The above makes it difficult to ensure optimal heat transfer and thermal condition of diesel parts in partial operating modes.

Closest to the claimed method of operation of a diesel engine is a method of operating the device with combining the functions of bypass regulation of a turbine and exhaust gas recirculation (Device for bypass regulation of a turbine and exhaust gas recirculation in a turbocharged diesel. RF patent No. 2159340 C1, 7 F02B 37/12, 37 / 18. Petukhov E.V., Lazarev E.A., Lavrik A.N., Pavlov A.N., Mitsyn G.P., Redko I.Y. Publ. 20.11.2000, Bull. No. 32). Simplification of the drive system of the device is achieved by using a single regulatory body, controlled by a given program and performing exhaust gas recirculation and bypass regulation of the turbine in a certain sequence.

At the same time, at idle and low loads, a part of the exhaust gas recirculates to the cylinder, which is sent, in addition to the turbine, in the bypass control process. As the diesel load increases, when exhaust gas recirculation into the cylinder becomes economically inexpedient, this part of the exhaust gas stream is emitted into the atmosphere. The latter is a significant drawback of the considered method and device for its implementation. The energy of the part of the exhaust gas stream emitted into the atmosphere is still quite high, but in this case it is useful not used when the diesel engine is operating at medium and nominal loads. The disadvantage of the considered device is also the reduced performance of the return spring located in the hot zone of the spool mechanism from the side of the exhaust gas supply.

The basis of the invention is the technical task of sequentially combining the functions of the bypass control of the turbine of the turbocharger and the ejection cooling of the charge air by using the energy of the exhaust stream flowing out of the bypass pipe when the exhaust gas recirculation to the diesel cylinder is stopped.

This problem is solved by the fact that in the method of controlling gas exchange in a diesel engine with gas turbine supercharging, which includes bypass regulation of the turbine of the turbocharger, cooling of the charge air, recirculation into the cylinder and ejection of exhaust gases, in which a smaller part is extracted from the total exhaust gas stream at the outlet of the exhaust manifold and direct, bypassing the turbine, at idle and low loads into cylinders for recirculation, at medium and nominal loads - into the atmosphere, and at overload modes straps, combining with the greater part, - the turbine according to the invention for medium and modes nominal loads smaller part stream fed to the ejector, and the ejector overload conditions directed full exhaust gas stream downstream of the turbocharger turbine.

Another difference is that when the ratio of the air pressure after the compressor to the exhaust gas pressure in front of the turbine is less than one, a smaller part of the flow is recirculated, and if this ratio is equal to or greater than one, the air is ejected through the cooler.

The proposed method allows the use of the energy of a portion of the exhaust gas stream to circulate ambient air through an intercooler of charge air by combining the bypass control functions of the turbocharger turbine and ejection cooling when the exhaust gas recirculation to the cylinder is stopped. With the subsequent termination of the bypass regulation of the turbine, this control method allows the use of the energy of the full exhaust gas stream after the turbine to circulate ambient air through the intercooler of charge air during its ejection cooling.

To implement the method, there is provided a gas exchange control device in a gas turbine diesel engine comprising a spool mechanism with a cylindrical body in which three channels are made, two of which are located opposite the third, and the axis of the latter is between the axes of the first two channels, and a regulating body with two pistons, connected by stock. According to the invention, two additional channels are made in the housing, one of which is located at the end of the housing and its axis coincides with the axis of the housing, and the other channel is located on the generatrix of the housing and its axis is perpendicular to the axis of the housing.

In addition, in the gas exchange control device, the end face of the spool mechanism housing is connected to the end face of the control cylinder housing located also in the spool mechanism housing, in which the working cavity is connected, connected to the intake manifold. The regulatory body of the device is equipped with an additional rod with an end stop and a return spring, which is supported at one end by the end stop of the rod, and the other into the restrictive partition.

The invention is illustrated by drawings, where figure 1 shows a General diagram of a gas exchange system of a diesel engine; figure 2 shows a gas exchange control device in the exhaust gas recirculation position in the diesel cylinder; figure 3 is the same, in the bypass bypass and ejection position of a smaller part of the exhaust gas stream; figure 4 is the same in the position of the ejection of the full flow of exhaust gases.

The control device is integrated into the gas exchange system (Figure 1). Diesel 1 is connected to the intake manifold 2 through an intercooler 3 of charge air air with the compressor 4 of the turbocharger. In front of the compressor inlet 4, a two-stage air purifier 5 is installed, through which ambient air enters the compressor. The compressor 4 is connected by a common shaft 6 with the turbine 7 of the turbocompressor. The exhaust manifold 8, connecting the turbine of the turbocompressor with the diesel 1, is divided into two pipes before entering the turbine 7. The pipe 9 connects the exhaust manifold 8 to the turbine body 7. The pipe 10 connects the exhaust manifold 8 to a gas exchange control device that directs the movement of gas flows flowing from the pipe 10 and the turbine pipe 11. The gas exchange control device comprises a spool with two pistons 12 and 13 connected by a rod 14. The spool is prevented from moving in the housing by a spring 15. The housing of the spool mechanism has five flanges for connection with supply pipelines and outlet pipes. A nozzle 16 is installed on the flange of one of the outlet pipes, forming, together with the mixing chamber 17 and the duct 18, an air ejector, in which the working fluid is the exhaust gas stream, and the surrounding atmosphere is atmospheric air. The duct 18 connecting the mixing chamber 17 of the ejector with the matrix of the intercooler 3 charge air, at the entrance to the latter has an input device 19. The flange of the other outlet pipe is connected to the recirculation channel 20.

The sequence of connection of the inlet pipes 10 and 11 with the outlet pipes is such that the inlet pipe 10 first communicates with the recirculation channel 20, while the inlet pipe 11 communicates with the outlet pipe of the ejector nozzle 16 and the outlet pipe 21. Then, the inlet pipe 10 is in communication with the outlet pipe of the nozzle 16 ejector, and the inlet pipe 11 with the outlet pipe 21. Finally, further, the inlet pipe 10 and the outlet pipe 21 are closed. In this case, the inlet pipe 11 communicates with the outlet nozzle nozzle 16 of the ejector.

The essence of the method of controlling gas exchange in a diesel engine is as follows. After starting the diesel engine at idle and light loads, the air stream from the atmosphere enters a two-stage air purifier 5, where it is cleaned of contaminants, and then under the action of the vacuum created by the rotating impeller, enters the compressor inlet 4. The air stream is compressed in the compressor, when In this case, its pressure and temperature increase, and is sent to the intercooler 3 of charge air, where heat exchange occurs between the charge air and the surrounding air circulating through cut cooler entering its input device 19. The circulation of ambient air is due to the ejection effect created by the outflow of part of the exhaust gases through the nozzle 16 of the ejector. After cooling in the intercooler 3, the air flow is directed to the intake manifold 2 and then to the diesel cylinders. In this case, the exhaust gas stream leaving the diesel cylinders enters the exhaust manifold 8 and is divided, bypassing the turbine, into two unequal parts, the larger of which enters the channel 9 and then into the turbine housing 7 of the turbocharger, and the smaller one into the inlet pipe 10 device for regulating the direction of movement of parts of the exhaust gas stream. Due to the low pressure of the charge air at idle and low loads, the rod 14 with the pistons 12 and 13 is in the lower position, in which a smaller part of the exhaust gas stream enters the exhaust pipe connected to the recirculation channel 20, and then through the intake manifold 2 this part of the exhaust gas stream enters the diesel cylinders, thus performing the process of recirculation of the working fluid.

With increasing load (average and nominal load modes) of a diesel engine, the charge air pressure in the intake manifold increases. The pressure rises in the cavity 22 of the control cylinder connected to the intake manifold. Under the influence of this pressure, the rod 14 with the pistons 12 and 13 moves upward, blocking the recirculation channel 20 and connecting the inlet pipe 10 to the outlet pipe of the ejector nozzle 16. The inlet pipe 11 of the device is connected to the exhaust pipe 21 and most of the exhaust gas stream after the turbine is directed to the exhaust device 23, and the ambient air circulation, according to the invention, is due to the ejection effect created by the outflow of part of the exhaust gas stream from the inlet pipe 10, performing at the same time and bypass regulation of the turbine, through the nozzle 16, the mixing chamber 17 of the ejector, channel 24 into the exhaust device 25.

The change in the direction of movement of a smaller part of the exhaust gas stream, according to the invention, is carried out depending on the ratio of the air pressure after the compressor to the pressure of the exhaust gases in front of the turbine. With a value of this ratio less than unity, a smaller part of the flow is recycled, and with a value of this ratio equal to and greater than one, ejection of ambient air through the cooler is performed.

With a further increase in the load (overload mode) of the diesel engine, an increase in the charge air pressure moves the rod 14 with the pistons 12 and 13 in such a way that the piston 13 closes the inlet pipe 10, thus stopping the bypass regulation of the turbine, and the piston 12 blocks the outlet pipe 21, thus directing, according to the invention, the full flow of exhaust gases after the turbine through the outlet pipe of the nozzle 16, the mixing chamber 17 of the ejector, the channel 24 to the exhaust device 25. In this case, the cooling is intensified charge air by increasing the flow of ambient air through the intercooler.

The implementation of the considered method of operation of a diesel engine with gas turbine pressurization is provided by a spool type gas exchange control device 26, which directs the movement of gas flows.

The essence of the design of this device is illustrated by the drawings in figures 2, 3, 4. The gas exchange control device consists of two main elements: the spool mechanism 27 and, according to the invention, the control cylinder 28.

The housing 29 of the spool mechanism 27 contains three channels 30, 31 and 32, two of which 31 and 32 are located opposite the third bypass channel 30, and the axis of the latter is between the axes of the first two channels 31 and 32 and the regulatory body with two pistons 12 and 13 connected the rod 14, according to the invention, is equipped with two more channels 33 and 34. The axis of the channel 34 located at the end of the housing coincides with its axis, and the axis of the channel 33 located on the generatrix of the housing 29 is perpendicular to the axis of the housing.

To supply charge air to the control cylinder 28, a fitting 35 is installed in the cover 36. The control cylinder 28 contains an additional rod 37 with an end stop 38 and a return spring 15. An additional rod moves in the cylinder under the influence of pressure of the charge air on one side and return spring 15 on the other. 37 with an end stop 38 connected to the piston 13, the main rod 14 and the piston 12. The opposite end of the return spring 15 abuts against the restrictive partition 39, which serves simultaneously as the bottom of the control cylinder 28. Ra the displacement of the return spring 15 in the relatively cold working cavity 40 of the control cylinder 28 is due to the desire to increase its performance.

The device operates as follows. Before starting the diesel engine and when it is operating at idle and light loads, the regulatory body, including pistons 12 and 13 connected by a rod 14, an additional rod 37 with an end stop 38, is held in position I (Figure 2) under the action of the force generated by the return spring 15, because in the cavity 40 of the control cylinder 28, the pressure of the charge air is low. In this position, the bypass channel 30 is in communication with the channel 32 and a smaller part of the exhaust gas, limited by the flow area and the pressure drop between the intake and exhaust manifolds, is recycled to the diesel cylinders. The ratio of charge air pressure to exhaust pressure is less than unity. In this case, the channel 33 communicates with the channels 34 and 31, which allows most of the exhaust gases to be directed through the channel 34 to the exhaust device 25, and through the channel 31 to the ejector nozzle 16 to eject the ambient air through the intercooler 3 of charge air.

With an increase in the diesel load (medium and nominal load modes), the temperature of the gases in front of the turbine and the turbine power increase, which leads to an increase in the rotor speed of the turbocompressor and the pressure of the charge air created by the compressor. An increase in the pressure of the charge air in the cavity 40 of the control cylinder 28 causes the regulating body to move, overcoming the resistance of the spring 15. The ratio of the pressure of the charge air to the pressure of the exhaust gases becomes equal, and then exceeds unity. In this case, the piston 13 will start to block the channel 32, and the piston 12 will open the channel 31. Upon completion of this process, the regulatory body will switch to position II (Figure 3), in which the bypass channel 30 communicates with the channel 31, and the channel 33 - with the channel 34. The communication of the channels 30 and 31 allows a smaller part of the exhaust gas to be directed into the nozzle 16 of the ejector to eject the ambient air through an intercooler 3 of charge air, and the communication of the channels 33 and 34 allows most of the exhaust gas to be directed to the exhaust device 25.

With a further increase in the load (overload mode) of the diesel engine, the turbine power continues to increase and, accordingly, the pressure of the charge air created by the compressor. The charge air pressure continues to increase in the cavity 40 of the control cylinder 28, which causes the regulatory body, overcoming the resistance of the spring 15, to move further. The ratio of charge air pressure to exhaust gas pressure is significantly greater than one. In this case, the piston 13 will begin to block the bypass channel 30, the piston 12 will block the channel 34, and the channel 33 will communicate with the channel 31. Upon completion of this process, the regulatory body will switch to position III (Figure 4). Thus, the bypass control process is stopped and the full flow of exhaust gases is directed to the turbocharger turbine, significantly increasing the turbine power. After the turbine, the full flow of exhaust gases through the channels 33 and 31 is directed into the nozzle 16 of the ejector to eject the ambient air through the intercooler 3 charge air.

Claims (5)

1. A method of controlling gas exchange in a diesel engine with gas turbine supercharging, including bypass regulation of the turbine of the turbocharger, cooling of the charge air, recirculation into the cylinder and ejection of exhaust gases, in which a smaller part is extracted from the total exhaust gas stream at the outlet of the exhaust manifold and directed, bypassing the turbine, at idle and low loads in the cylinders for recirculation, at medium and nominal loads - into the atmosphere, and at overload modes, combining with most of them - in Urbino, characterized in that on the secondary modes and nominal loads smaller part stream fed to the ejector, and the ejector overload conditions directed full exhaust gas stream downstream of the turbocharger turbine. 2. The method according to claim 1, characterized in that when the ratio of the air pressure after the compressor to the exhaust gas pressure in front of the turbine is less than one, a smaller part of the flow is recirculated, and if this ratio is equal to or greater than one, the surrounding air is ejected through the cooler. 3. A gas exchange control device in a gas turbine diesel engine, comprising a spool mechanism with a cylindrical body in which three channels are made, two of which are located opposite the third, and the axis of the latter is between the axes of the first two channels, and a regulatory body with two pistons connected by a rod , characterized in that the housing has two additional channels, one of which is located in the end of the housing and its axis coincides with the axis of the housing, and the other channel is located on the generatrix of the housing and its axis perpendicular to the axis of the housing. 4. The device according to claim 3, characterized in that the end face of the spool mechanism housing is connected to the end face of the control cylinder body located also in the spool mechanism housing, in which the working cavity is connected, connected to the intake manifold. 5. The device according to claim 3, characterized in that the regulatory body is equipped with an additional rod with an end stop and a return spring, which is abutted by one end to the end stop of the rod, and the other into a restrictive partition.

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