Exhaust gas turbocharger coaxially driven by variable frequency motor and exhaust gas turbine and two-stage supercharging system of diesel engine

Abstract

The invention discloses an exhaust gas turbocharger coaxially driven by a variable frequency motor and an exhaust gas turbine and a two-stage supercharging system of a diesel engine. An exhaust gas turbocharger coaxially driven by a variable frequency motor and an exhaust gas turbine comprises a gas compressor, a pressing shell, the exhaust gas turbine, a volute, a motor and a synchronous rotating shaft. The gas compressor and the waste gas turbine rotate synchronously through the synchronous rotating shaft, the gas compressor is matched with the pressing shell, and the waste gas turbine is matched with the volute. According to the technical scheme, waste gas energy in exhaust gas of the diesel engine is recycled, motor energy consumption of the first-stage waste gas turbocharger is reduced, the pressure and flow of an air outlet of an air compressor of the first-stage waste gas turbocharger can be adjusted in real time by adjusting the rotating speed of a motor according to the combustion requirement of the diesel engine, and the purpose of energy conservation and emission reduction is achieved. And therefore, the pressurized air pressure and flow supplied to the diesel engine by the second-stage exhaust gas turbocharger are controllable.

Description

Technical Field

[0001] The present invention relates to an exhaust gas turbocharger and a two-stage supercharging system driven coaxially by a variable frequency motor and an exhaust gas turbine, which are suitable for diesel engines of various purposes to increase the pressure and flow of supercharged air, and can adjust the pressure and flow of supercharged air according to various operating states of the diesel engine. Background Art

[0002] As the name suggests, the two-stage exhaust gas turbocharged diesel engine uses the exhaust energy of the diesel engine to convert heat energy into rotational mechanical energy through the two-stage turbine step and drive the two-stage compressor to rotate at high speed, and then compress the air to provide the diesel engine with a higher boost air pressure, so as to increase the output power of the diesel engine, reduce fuel consumption, and reduce pollutant emissions.

[0003] The exhaust gas turbocharger used in the above diesel engine is mainly composed of a high-speed rotating compressor and an exhaust gas turbine, in which the compressor is arranged at the intake pipe position, and the exhaust gas turbine is at the exhaust pipe position and drives the compressor to rotate. Its material is limited by mechanical and thermal loads, which makes the amount of exhaust gas energy converted by the single-stage exhaust gas turbocharger limited. The latest generation of single-stage exhaust gas turbochargers at home and abroad have reached a boost pressure ratio of 5.5. With the increase in diesel engine power density and increasingly stringent emission restrictions, the boost air pressure and flow required by diesel engines are still increasing. The use of single-stage exhaust gas turbocharging technology can no longer meet the needs of diesel engine development. The two-stage supercharging technology has become a major technical option for diesel engines at present and in the future, and has been widely used in high-power density diesel engines.

[0004] At present, the two-stage exhaust gas turbocharging technology, as the name implies, uses the original single-stage exhaust gas turbocharger diesel engine, and connects another exhaust gas turbocharger in series before or after its exhaust gas turbocharger. Through the step-by-step utilization of the diesel engine exhaust gas energy, the exhaust gas energy is distributed to the turbine of the first-stage exhaust gas turbocharger and the turbine of the second-stage exhaust gas turbocharger, thereby driving the compressor of the first-stage exhaust gas turbocharger and the compressor of the second-stage exhaust gas turbocharger to step-pressurize the air to increase the intake pressure and flow of the diesel engine, so that the diesel engine can generate more power and improve its power density. Since the diesel engine two-stage exhaust gas turbocharging system relies on the diesel engine's own exhaust gas energy, when the diesel engine is running at partial load and when low speed and high torque are required, the exhaust gas energy is seriously insufficient, and it is impossible to achieve efficient operation of the turbine of the first-stage exhaust gas turbocharger and the turbine of the second-stage exhaust gas turbocharger through reasonable energy distribution. At this time, the air pressure and flow obtained by the diesel engine cannot meet the operating needs, the combustion process deteriorates, the energy consumption increases, and the exhaust emits black smoke.

[0005] At present, the two-stage supercharging system used in diesel engines at home and abroad mainly adopts exhaust gas turbocharging or electric supercharging technology. The two-stage exhaust gas turbocharging system and electric supercharging system have the following problems: 1. Diesel engines for various purposes, especially high-power density diesel engines, have a serious lack of exhaust gas energy at low and medium loads, and can only maintain the normal operation of one of the first-stage exhaust gas turbochargers. When a two-stage exhaust gas turbocharger, i.e. a two-stage turbocharger consisting of two exhaust gas turbochargers, is added, the exhaust gas energy is sufficient and reasonably distributed under high operating conditions such as full load, which can ensure that the two-stage turbocharger obtains enough exhaust gas energy and operates within their respective normal operating ranges; however, when the diesel engine is partially loaded, the total exhaust gas energy of the diesel engine drops sharply, and it is impossible to ensure that the two-stage turbocharger operates within the normal range through reasonable distribution. The diesel engine has insufficient intake air, incomplete combustion, and increased energy consumption per unit output power. In severe cases, a large amount of black smoke is emitted from the exhaust, polluting the environment.

[0006] 2. The air pressure and flow rate output by the first-stage exhaust gas turbocharger and the second-stage exhaust gas turbocharger in the conventional two-stage exhaust gas turbocharging system have been matched in the overall design. The diesel engine can no longer be adjusted and re-matched according to the output power and torque requirements under various working conditions. Even if there is a large deviation from the original overall matching design and adjustment is required, the diesel engine needs to be stopped to implement the adjustment, and real-time online adjustment cannot be achieved, which brings great inconvenience to diesel engine users, especially when the diesel engine is used as the main power of the ship, the prime mover of emergency power generation, the prime mover of the backup power supply of the nuclear power plant, etc., and cannot be stopped. At this time, the output power and torque of the diesel engine cannot meet the use requirements.

[0007] 3. Some diesel engines using conventional two-stage exhaust gas turbocharging systems are designed with a tangential booster device with a common motor and a bevel gear, which is mainly used to solve the problem of too low acceleration of the two-stage turbocharger during the diesel engine startup phase. When the diesel engine enters normal operating state, the tangential booster device is withdrawn, and the above-mentioned problems 1 and 2 still exist.

[0008] 4. The secondary supercharging system of the compressor of the first-stage exhaust gas turbocharger driven by a high-speed motor has a wide speed adjustment range and can provide the required boost air flow and pressure for various operating conditions of the diesel engine in real time, ensuring the high operating efficiency of the diesel engine under various operating conditions. However, since the first-stage compressor is all driven by a high-speed motor, the exhaust gas energy of the diesel engine cannot be utilized in a step-by-step manner. Summary of the invention

[0009] The purpose of the present invention is to provide an exhaust gas turbocharger driven by a variable frequency motor and an exhaust gas turbine coaxially, and the technical problem to be solved is: to recycle the exhaust gas energy in the exhaust of the diesel engine, reduce the motor energy consumption of the first-stage exhaust gas turbocharger, and adjust the air outlet pressure and flow of the compressor of the first-stage exhaust gas turbocharger in real time according to the combustion needs of the diesel engine by adjusting the motor speed, so as to achieve the controllable pressure and flow of the pressurized air provided to the diesel engine by the second-stage exhaust gas turbocharger. Due to the wide range of motor speed adjustment, the diesel engine can adapt to the use environment, so that it can always run efficiently at various operating points and output the power and torque required by the user in real time, so that the diesel engine can maintain low energy consumption and low harmful substance emissions in the entire operating range, and meet the energy consumption rate and emission index requirements of the diesel engine under various operating conditions.

[0010] Another object of the present invention is to provide a two-stage supercharging system of an exhaust gas turbocharger using the above-mentioned variable frequency motor and the exhaust gas turbine to drive the motor coaxially.

[0011] The exhaust gas turbocharger driven coaxially by a variable frequency motor and an exhaust gas turbine is characterized in that it includes a compressor, a compressor casing, an exhaust gas turbine, a volute, a motor, and a synchronous rotating shaft; the compressor rotates synchronously with the exhaust gas turbine through the synchronous rotating shaft, the compressor cooperates with the compressor casing, the exhaust gas turbine cooperates with the volute, the compressor is installed at one end of the synchronous rotating shaft, and the motor and the exhaust gas turbine are installed at the other end of the synchronous rotating shaft; the exhaust gas turbine and the motor jointly drive the compressor to rotate; the synchronous rotating shaft and the output shaft of the motor rotate at the same speed; the motor uses electrical energy, and the exhaust gas turbine uses exhaust gas energy to jointly drive the compressor at one end of the synchronous rotating shaft to rotate, thereby realizing the first stage of supercharging of a two-stage supercharged diesel engine.

[0012] A first flange is installed on the output shaft of the motor and fixed to the volute. The output shaft of the motor passes through the first flange, and the first flange has an air outlet. A second flange is provided between the compression shell and the volute, and the synchronous rotating shaft passes through the second flange.

[0013] The synchronous rotating shaft and the output shaft of the motor are kept rotating at the same speed through another flange or an integrated structure.

[0014] The diesel engine two-stage supercharging system comprises the above-mentioned exhaust gas turbocharger forming a first-stage exhaust gas turbocharger to constitute a first-stage supercharging, and the original exhaust gas turbocharger of the diesel engine forming a second-stage exhaust gas turbocharger to constitute a second-stage supercharging; the air after the first-stage supercharging flows into the compressor of the second-stage exhaust gas turbocharger of the diesel engine through the air pipe to realize the two-stage supercharging of the air, and the compressor shell of the first-stage exhaust gas turbocharger has an air inlet and an air outlet, the air inlet is connected to the atmosphere, and the air outlet is connected to the air inlet of the second-stage exhaust gas turbocharger of the diesel engine; the first The volute of the first-stage exhaust gas turbocharger has an exhaust gas inlet and an exhaust gas outlet, the exhaust gas inlet is connected to the exhaust gas outlet of the second-stage exhaust gas turbocharger of the diesel engine, and the exhaust gas outlet is connected to the atmospheric environment; the compressor of the above-mentioned first-stage exhaust gas turbocharger is jointly driven by low-pressure exhaust gas and a coaxial motor, and the speed of the compressor is not controlled by the exhaust gas energy absorption capacity inherent in the exhaust gas turbine but is controlled by a variable frequency motor, and has the ability to provide the diesel engine with the air flow and pressure required in real time; the compressor of the second-stage exhaust gas turbocharger is all driven by high-pressure exhaust gas.

[0015] The beneficial effects of the present invention are: combining the conventional two-stage exhaust gas turbocharger system and the high-speed motor to drive the compressor of the first-stage exhaust gas turbocharger to achieve the advantages of two-stage supercharging, not only the step-by-step utilization of exhaust gas energy to reduce energy consumption, but also the coaxial drive of the high-speed motor, so as to achieve the adjustable speed of the supercharger that does not rely on exhaust gas energy. The compressor of the first-stage exhaust gas turbocharger directly rotates by using the exhaust gas turbine and the high-speed motor coaxially, and preferentially utilizes the exhaust gas energy to drive in various operating states of the diesel engine, so as to achieve energy conservation and emission reduction. While having the performance and technical indicators of the two-stage supercharged diesel engine, the high-speed motor is used as a coaxial supplementary drive, and the speed adjustment of the high-speed variable frequency motor is fast and wide, so that the flow and pressure provided by the two-stage supercharging meet various operating requirements of the diesel engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a three-dimensional schematic diagram of an exhaust gas turbocharger in which a variable frequency motor and an exhaust gas turbine are coaxially driven; Figure 2 It is a three-dimensional schematic diagram from another angle of the exhaust gas turbocharger driven coaxially by the variable frequency motor and the exhaust gas turbine; Figure 3 It is an exploded schematic diagram of an exhaust gas turbocharger in which a variable frequency motor and an exhaust gas turbine are coaxially driven; Figure 4 It is a schematic diagram of another angle of the exhaust gas turbocharger driven coaxially by the variable frequency motor and the exhaust gas turbine; Figure 5 It is a third angle exploded schematic diagram of an exhaust gas turbocharger driven coaxially by a variable frequency motor and an exhaust gas turbine; Figure 6It is a cross-sectional view of an exhaust gas turbocharger in which a variable frequency motor and an exhaust gas turbine are coaxially driven; Figure 7 It is a schematic diagram of a two-stage supercharging system of an exhaust gas turbocharger that uses a variable frequency motor and an exhaust gas turbine to coaxially drive; In the figure 1. Compressor; 2. Press shell; 3. Exhaust gas turbine; 4. Volute; 5. Motor, 51. Output shaft; 6. Synchronous rotating axis; 71. first flange, 711. air outlet, 72. second flange; 81. First stage exhaust gas turbocharger, 82. Second stage exhaust gas turbocharger, 83. Air pipe. DETAILED DESCRIPTION

[0017] Please refer to Figures 1 to 7 The exhaust gas turbocharger in which the variable frequency motor 5 and the exhaust gas turbine 3 are coaxially driven, as shown in the figure, mainly designs the compressor 1, the compressor housing 2, the exhaust gas turbine 3, the volute 4, the motor 5, the synchronous rotating shaft 6 and other components. In this case, the motor 5 drives the synchronous rotating shaft 6 to rotate synchronously, and then further drives the compressor 1 and the exhaust gas turbine 3 to rotate together, so as to realize the driving of the compressor 1 by the motor 5. The assembly structure between the compressor 1 and the compressor housing 2, and between the exhaust gas turbine 3 and the volute 4, such as the configuration of bearings, etc., can adopt the existing method.

[0018] The structure and mutual assembly method of the compressor 1 and the compression casing 2 in the figure can refer to the compressor 1 and the compression casing 2 components in the original supercharger currently applied to the diesel engine. The compressor 1 has an air inlet and an air outlet for fresh air circulation.

[0019] The structure and mutual assembly method of the exhaust gas turbine 3 and the volute in the figure can also refer to the exhaust gas turbine 3 and the volute components in the original supercharger currently applied to the diesel engine. The exhaust gas turbine 3 also has an air inlet and an air outlet for the exhaust gas circulation.

[0020] In this case, a synchronous rotating shaft 6 is installed between the compressor 1 and the exhaust gas turbine 3 in the existing manner. The synchronous rotating shaft 6 keeps rotating synchronously with the output shaft 51 of the motor 5. Specifically, the synchronous rotating shaft and the output shaft of the motor can keep rotating at the same speed through another flange or an integrated structure, so that the motor 5 can drive the synchronous rotating shaft 6 to rotate through the output shaft 51 thereon, and then drive the compressor 1 and the exhaust gas turbine 3 to rotate. As shown in the figure, the compressor 1 is installed at one end of the synchronous rotating shaft 6, and the exhaust gas turbine 3 and the motor 5 are installed at the other end of the synchronous rotating shaft 6 respectively. In operation, the exhaust gas turbine 3 and the motor 5 jointly drive the compressor 1 to work, that is, the motor 5 uses electrical energy and the exhaust gas turbine 3 uses exhaust gas energy to jointly drive the compressor 1 on the other side of the synchronous rotating shaft 6 to rotate, which can be used as the first stage of supercharging of a two-stage supercharged diesel engine.

[0021] In order to facilitate the installation of various components of the exhaust gas turbocharger, as shown in the figure, a first flange 71 is installed on the output shaft 51 of the motor 5 and fixed to the volute 4, and the output shaft 51 of the motor 5 remains through the above-mentioned first flange 71 and is fixed together with the synchronous rotating shaft 6. In order to facilitate the exhaust gas outflow of the volute 4, the side wall of the above-mentioned first flange 71 can be penetrated to form an air outlet 711. In order to facilitate the installation between the compressor housing 2 and the volute 4, a second flange 72 can be installed between the two, and similarly, the synchronous rotating shaft 6 remains through the second flange 72.

[0022] The two-stage supercharging system in the figure uses the above exhaust gas turbocharger and the original exhaust gas turbocharger, wherein the above exhaust gas turbocharger forms the first-stage exhaust gas turbocharger 81 to constitute the first-stage supercharging, and the original exhaust gas turbocharger of the diesel engine, that is, the second-stage exhaust gas turbocharger 82, serves as the second-stage supercharging. Figure 6 As shown in , the compressor housing 2 of the first-stage exhaust gas turbocharger 81 has an air inlet and an air outlet, the air inlet is connected to the atmosphere, and the air outlet is connected to the air inlet of the second-stage exhaust gas turbocharger 82 of the diesel engine. Similarly, the volute 4 of the first-stage exhaust gas turbocharger 81 has an exhaust gas inlet and an exhaust gas outlet, the exhaust gas inlet is connected to the exhaust gas outlet of the second-stage exhaust gas turbocharger 82 of the diesel engine, and the exhaust gas outlet is connected to the atmospheric environment. After the first-stage supercharging, the outside air flows into the compressor 1 of the second-stage exhaust gas turbocharger 82 of the diesel engine through the air pipe 83 to realize the secondary air supercharging. The compressor 1 of the above-mentioned first-stage exhaust gas turbocharger 81 is jointly driven by low-pressure exhaust gas and a coaxial motor 5. The speed of the compressor 1 is not controlled by the exhaust gas energy absorption capacity inherent in the exhaust gas turbine 3 but is controlled by the variable frequency motor 5, and has the ability to provide the diesel engine with the air flow and pressure required in real time; the compressor 1 of the second-stage exhaust gas turbocharger 82 is entirely driven by high-pressure exhaust gas.

[0023] Through the above configuration, the compressor 1 of the first-stage exhaust gas turbocharger 81 is coaxially connected and driven by the high-speed variable frequency motor 5 to recycle the exhaust gas energy of the diesel engine. When the diesel engine is running at full load, the exhaust gas energy is sufficient, and the exhaust gas energy is used as much as possible to reduce the power consumption of the high-speed motor 5. When the diesel engine is running at low load, the exhaust gas energy is insufficient, and the driving capacity of the high-speed motor 5 is increased by variable frequency speed regulation to achieve the air pressure and flow required for the operation of the diesel engine. The coaxial variable frequency speed regulation motor 5 installed on the synchronous rotating shaft 6 of the first-stage exhaust gas turbocharger 81 of the present invention can adjust the speed of the first-stage exhaust gas turbocharger 81 in real time without relying on the exhaust gas energy to achieve two-stage supercharging. While improving the power density of the diesel engine, it solves the air volume and pressure required for the diesel engine at high, medium and low loads to meet the use requirements of low-speed, high-torque and high-speed full-load diesel engines for various purposes.

[0024] The specific embodiments described above are only used to explain the present technical solution and are not used to limit the present technical solution. In the description of the present technical solution, it should be noted that the terms such as "upper" and "inner" indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present technical solution and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present technical solution.

[0025] At the same time, in the description of this technical solution, it should be noted that, unless otherwise clearly specified and limited, the terms "fixed" and "matched" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this technical solution can be understood according to specific circumstances.

[0026] Although embodiments of the present technical solution have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present technical solution, and that the scope of the present technical solution is defined by the appended claims and their equivalents.

Claims

1. An exhaust gas turbocharger driven coaxially by a variable frequency motor and an exhaust gas turbine, characterized in that: The invention comprises a compressor (1), a compressor casing (2), an exhaust gas turbine (3), a volute (4), a motor (5), and a synchronous rotating shaft (6); the compressor (1) rotates synchronously with the exhaust gas turbine (3) via the synchronous rotating shaft (6); the compressor (1) cooperates with the compressor casing (2), and the exhaust gas turbine (3) cooperates with the volute (4); the compressor (1) is mounted on one end of the synchronous rotating shaft (6), and the motor (5) and the exhaust gas turbine (3) are mounted on the other end of the synchronous rotating shaft (6); the exhaust gas turbine (3) and the motor (5) jointly drive the compressor (1) to rotate; the synchronous rotating shaft (6) and the output shaft (51) of the motor (5) rotate at the same speed; the motor (5) utilizes electric energy, and the exhaust gas turbine (3) utilizes exhaust gas energy to jointly drive the compressor (1) at one end of the synchronous rotating shaft (6) to rotate, thereby realizing the first stage supercharging of the two-stage supercharged diesel engine.

2. The exhaust gas turbocharger coaxially driven by the variable frequency motor and the exhaust gas turbine according to claim 1 is characterized in that: A first flange (71) is mounted on the output shaft (51) of the motor (5) and is fixed to the volute (4); the output shaft (51) of the motor (5) passes through the first flange (71); the first flange (71) has an air outlet (711); a second flange (72) is provided between the compression shell (2) and the volute (4); the synchronous rotating shaft (6) passes through the second flange (72).

3. The exhaust gas turbocharger coaxially driven by the variable frequency motor and the exhaust gas turbine according to claim 1 is characterized in that: The synchronously rotating shaft (6) and the output shaft (51) of the motor (5) rotate at the same speed via another flange or an integrated structure.

4. Two-stage turbocharging system for diesel engine, characterized by: The invention comprises an exhaust gas turbocharger coaxially driven by a variable frequency motor and an exhaust gas turbine as described in claim 1, 2 or 3; the exhaust gas turbine (3) supercharger forms a first-stage exhaust gas turbocharger (81) to constitute a first-stage supercharging, and the original exhaust gas turbine (3) supercharger of the diesel engine forms a second-stage exhaust gas turbocharger (82) to constitute a second-stage supercharging; the air after the first-stage supercharging flows into the compressor (1) of the second-stage exhaust gas turbocharger (82) of the diesel engine through an air pipe (83) to realize the air two-stage supercharging, and the compressor shell (2) of the first-stage exhaust gas turbocharger (81) has an air inlet and an air outlet, the air inlet is connected to the atmosphere, and the air outlet is connected to the second-stage exhaust gas turbocharger (82) of the diesel engine. ); the volute (4) of the first-stage exhaust gas turbocharger (81) has an exhaust gas inlet and an exhaust gas outlet, the exhaust gas inlet is connected to the exhaust gas outlet of the second-stage exhaust gas turbocharger (82) of the diesel engine, and the exhaust gas outlet is connected to the atmospheric environment; the compressor (1) of the first-stage exhaust gas turbocharger (81) is jointly driven by low-pressure exhaust gas and a coaxial motor (5), the speed of the compressor (1) is not controlled by the inherent exhaust gas energy absorption capacity of the exhaust gas turbine (3) but is controlled by the variable frequency motor (5), and has the ability to provide the diesel engine with the air flow and pressure required in real time; the compressor (1) of the second-stage exhaust gas turbocharger (82) is completely driven by high-pressure exhaust gas.

Images