Exhaust energy recovery device and method for hybrid vehicle based on variable geometry turbine

Abstract

The application provides a hybrid vehicle exhaust energy recovery device and method based on a variable geometry turbine, which comprises an exhaust gas power generation and storage unit, an exhaust gas supercharging unit and a control unit. The exhaust gas power generation and storage unit comprises a first exhaust pipe, a power turbine and an electric energy system. The exhaust gas supercharging unit comprises a second exhaust pipe, a supercharging turbine and a compressor. The control unit comprises an electric quantity sensor, a PLC controller and a reversing valve. The air inlets of the first and second exhaust pipes are connected with a main exhaust pipe. The reversing valve is arranged on the main exhaust pipe and corresponds to the first and second exhaust pipes. The power turbine is connected with the electric energy system. The supercharging turbine is connected with the compressor. The input end of the PLC controller is electrically connected with the electric quantity sensor. The output end of the PLC controller is electrically connected with the reversing valve. The electric quantity sensor is connected with the electric energy system. The application improves the utilization efficiency of exhaust gas, improves the utilization efficiency of the generator as a whole, and improves the economy and environmental protection of the hybrid vehicle as a whole.

Description

Technical Field

[0001] This invention relates to the field of energy recovery in hybrid electric vehicles, and more particularly to the field of engine energy saving and emission reduction, specifically to a hybrid electric vehicle exhaust gas energy recovery device and method based on a variable geometry turbine. Background Technology

[0002] Hybrid electric vehicles utilize at least two different power sources that work together in a specific logical manner to achieve better fuel economy, power performance, and improved emissions performance compared to single-powered vehicles. Currently, most mature hybrid models on the market use an internal combustion engine as the primary power source, with other power sources such as batteries serving as auxiliary power sources. However, some plug-in hybrid electric vehicles (PHEVs) on the market primarily use batteries as the primary power source, with an internal combustion engine as an auxiliary power source. These PHEVs are more expensive, the technology is not yet mature, and their adoption rate is relatively low. Therefore, this invention primarily focuses on hybrid electric vehicles.

[0003] Exhaust gas turbine power generation technology is a relatively effective method among various approaches to recovering and utilizing energy from automotive engine exhaust gases. It can serve as an effective way to supplement automotive electrical energy and has promising development prospects. Currently, power generation technologies based on the principle of exhaust gas turbine power generation can be summarized into three types: 1. Turbine power generation technology based on the Rankine cycle, which adds a Rankine cycle subsystem to the engine exhaust system, converting low-grade heat energy into high-grade heat energy; 2. Turbine power generation technology based on the Brayton cycle, which adds a Brayton cycle subsystem to the engine exhaust system. This subsystem consists of four components: a heat exchanger, a power turbine, a compressor, and a generator, realizing the conversion of heat energy into electrical energy; 3. Turbine power generation technology based on a power turbine. This technology can be divided into two forms: electric-assisted turbocharging system and direct exhaust gas turbine power generation system. The electric-assisted turbocharging system installs a high-speed motor on the main shaft of the turbocharger, which can be both electrically driven and rotate to generate electricity. However, this technology needs to solve technical problems such as system heat dissipation, high-speed rotor bearing design, and control strategies, so there are certain technical limitations in practical applications. The direct exhaust gas turbine power generation system installs the turbine and the high-speed generator on the same shaft. It uses the kinetic energy of the exhaust gas to drive the turbine to rotate, and at the same time drives the coaxial high-speed generator to rotate and generate electricity, realizing the conversion of exhaust gas kinetic energy into electrical energy.

[0004] From a thermal balance perspective, besides being converted into useful mechanical energy, about one-third of the energy generated by automobile fuel combustion is directly carried away and dissipated into the air through high-temperature exhaust gases, resulting in energy waste and environmental thermal pollution. Improving engine energy utilization efficiency has always been a focus of attention. Given the immaturity of new energy vehicle technologies, research into exhaust gas energy recovery and utilization technologies has become a new trend in the automotive industry. Exhaust gas energy recovery can further improve the fuel economy of hybrid vehicles, reduce emissions, and decrease energy dissipation. Therefore, a major development direction for hybrid vehicles is the integrated application of power systems and energy recovery systems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a hybrid vehicle exhaust gas energy recovery device and method based on a variable geometry turbine, which addresses the above-mentioned problems.

[0006] The embodiments of this application are implemented as follows:

[0007] This application provides a hybrid vehicle exhaust gas energy recovery device based on a variable geometry turbine, characterized in that it includes an exhaust gas power generation and storage unit, an exhaust gas boosting unit, and a control unit. The exhaust gas power generation and storage unit includes a first exhaust gas pipe, a power turbine, and an electrical system. The exhaust gas boosting unit includes a second exhaust gas pipe, a boosting turbine, and a compressor. The control unit includes a power sensor, a PLC controller, and a reversing valve. The inlets of the first and second exhaust gas pipes are respectively connected to the main exhaust pipe. The reversing valve is located on the main exhaust pipe and corresponds to the first and second exhaust gas pipes. The power turbine and the boosting turbine are respectively located on the first and second exhaust gas pipes. The power turbine is connected to the electrical system, and the boosting turbine is connected to the compressor. The input terminal of the PLC controller is electrically connected to the power sensor, and the output terminal is electrically connected to the reversing valve. The power sensor is connected to the electrical system.

[0008] In some alternative implementations, both the power turbine and the booster turbine are variable geometry turbines.

[0009] In some alternative implementations, the power system includes a generator, an inverter, a filter, and a battery connected in sequence, with a power turbine coaxially connected to the generator, and a power sensor measuring the state of charge of the battery.

[0010] In some optional embodiments, the variable geometry turbine includes a vortex housing and multiple sets of geometrically variable blades evenly spaced along the circumference of the rotation axis, all housed within the vortex housing. Each set of geometrically variable blades includes a main blade and a secondary blade. The main blade has a cavity inside and an opening on its top surface that communicates with the cavity. The secondary blade is embedded in the cavity and is telescoped and limited by an elastic limiting mechanism.

[0011] In some optional implementations, the elastic limiting mechanism includes a limiting bracket and a limiting spring. The limiting bracket is fixed to the bottom of the auxiliary blade, and lower limiting posts are symmetrically arranged on both sides of the top. Upper limiting posts are symmetrically arranged on both sides of the opening of the main blade. The upper and lower limiting posts are symmetrically arranged in pairs. There are two limiting springs, and the upper and lower ends of each limiting spring are respectively fitted and positioned with the upper and lower limiting posts on the corresponding sides.

[0012] A control method for a hybrid vehicle exhaust gas energy recovery device based on a variable geometry turbine, characterized by comprising the following steps:

[0013] S1) Hybrid vehicles require less driving force during start-up and low-speed driving, and rely on the electric motor to provide the driving force required for driving.

[0014] S2) When a hybrid vehicle is driving under conditions such as rapid acceleration and hill climbing, it requires a large driving force. At this time, the power sensor installed on the battery will collect its state of charge and send the signal to the PLC controller. The PLC controller controls the opening and closing of the reversing valve according to the state of charge of the power system to change the direction of exhaust gas flow.

[0015] In some optional implementations, step S2 specifically includes the following control measures:

[0016] S21) If the electrical system is in a high state of charge, most of the driving force comes from the motor, with the engine playing an auxiliary role. The PLC controller controls the opening and closing of the reversing valve, the first exhaust pipe is closed, and all the exhaust gas enters the second exhaust pipe. The exhaust gas then flows into the turbocharger, driving the compressor that is coaxially linked with it to work and perform turbocharging. Since the engine is working in a high state of charge, the engine will not work under high load at this time.

[0017] S22) If the battery is low in charge, the PLC controller controls the opening and closing of the reversing valve, the second exhaust pipe is closed, and all the exhaust gas enters the first exhaust pipe, driving the power turbine to rotate. Subsequently, the generator connected to it on the same shaft rotates to generate electricity. Under this condition, because the driving force required by the car increases, the engine will experience a transition from low load to high load working state.

[0018] The method for operating the variable geometry turbine in a hybrid vehicle exhaust gas energy recovery device based on a variable geometry turbine is characterized by comprising the following steps:

[0019] S1) When the car engine is operating under low load, the amount of exhaust gas is small. Only the secondary blades of the variable geometry turbine extend out under the interaction of spring force and gravity, while the rest of the blades remain in the cavity of the main blades. This results in a larger clearance for the entire variable geometry turbine, reducing the resistance to exhaust gas when the engine starts to work.

[0020] S2) During the process of changing from low load to high load in a car engine, the exhaust gas velocity and flow rate will increase. The turbine speed may not be able to match its centrifugal force. At this time, the larger exhaust gas flow rate causes the variable geometry turbine to rotate and generate centrifugal force. The limiting spring between the main blade and the secondary blade will be compressed, and the secondary blade will extend to obtain greater torque to meet the turbine's optimal working efficiency. At the same time, because the extension of the secondary blade is coordinated and matched with the turbine speed, the variable geometry turbine still leaves a certain gap so that the exhaust gas resistance is not too large.

[0021] S3) When the car engine is working at full load, the exhaust gas flow reaches its maximum value. At this time, the auxiliary blades of the variable geometry turbine are fully extended, and the upper and lower limit posts are in contact, thereby obtaining the maximum designed torque and driving the generator to generate more electrical energy.

[0022] S4) When the car completes a hill climb or accelerates rapidly, requiring a large driving force, the engine stops working, and the turbine speed gradually decreases over time. Its centrifugal force also decreases. At this time, the limit spring slowly returns to its original deformation, retracting the auxiliary blades into the cavity, thereby reducing the blade area and the resistance to exhaust gas, thus adjusting the speed and ensuring that the turbine rotates in the best working condition.

[0023] The beneficial effects of this application are as follows: This application provides a hybrid vehicle exhaust gas energy recovery device and method based on a variable geometry turbine. It innovatively designs a variable geometry turbine and applies it to the exhaust gas recovery device of a hybrid vehicle. This not only avoids the huge waste of exhaust gas energy but also improves the overall utilization efficiency of the generator, thus enhancing the overall economy and environmental friendliness of the hybrid vehicle. The blades of the variable geometry turbine can freely extend and retract according to changes in turbine speed, thereby better matching the load under different operating conditions. This not only improves the turbine's regulation performance but also enhances the utilization efficiency of exhaust gas, achieving both energy saving and emission reduction, and improving fuel economy. The variable geometry turbine has a high utilization rate of exhaust gas energy, and this device does not require major modifications to the internal structure of existing automotive engines. The device is compact and easy to manufacture, making it a promising research direction among existing automotive energy-saving methods. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the device distribution according to an embodiment of this application;

[0026] Figure 2 This is a state diagram of a high state of charge according to an embodiment of this application;

[0027] Figure 3 This is a state diagram of a low state of charge according to an embodiment of this application;

[0028] Figure 4 This is a split schematic diagram of the geometrically variable blade according to an embodiment of this application;

[0029] Figure 5 This is a schematic diagram of the operation of the variable geometry turbine when the engine is operating under low load, according to an embodiment of this application.

[0030] Figure 6 This is a schematic diagram of the operation of the variable geometry turbine when the engine is operating at full load according to an embodiment of this application. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0036] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0039] like Figure 1As shown, this invention provides a hybrid vehicle exhaust gas energy recovery device based on a variable geometry turbine, including an exhaust gas power generation and storage unit, an exhaust gas boosting unit, and a control unit. The exhaust gas power generation and storage unit includes a first exhaust gas pipe 1, a power turbine 2, and an electrical energy system. The exhaust gas boosting unit includes a second exhaust gas pipe 3, a boosting turbine 4, and a compressor 5. The control unit includes a power sensor, a PLC controller 6, and a reversing valve 7. The air inlets of the first and second exhaust gas pipes are respectively connected to the main exhaust pipe 8. The reversing valve is located on the main exhaust pipe and corresponds to the first and second exhaust gas pipes. The power turbine and the boosting turbine are respectively located on the first and second exhaust gas pipes. The power turbine is connected to the electrical energy system, and the boosting turbine is connected to the compressor. The input terminal of the PLC controller is electrically connected to the power sensor, and the output terminal is electrically connected to the reversing valve. The power sensor is connected to the electrical energy system.

[0040] In some alternative implementations, the power system includes a generator 9, an inverter 10, a filter 11, and a battery 12 connected in sequence, with a power turbine coaxially connected to the generator, and a power sensor measuring the state of charge of the battery.

[0041] The control method using the above-mentioned waste gas energy recovery device includes the following steps:

[0042] 1. Hybrid vehicles require less driving force during start-up and low-speed driving, relying on the electric motor to provide the driving force needed for propulsion.

[0043] 2. When a hybrid vehicle is driving under conditions such as rapid acceleration and hill climbing, it requires a large driving force. At this time, the power sensor installed on the battery will collect its state of charge and send the signal to the PLC controller. The PLC controller controls the opening and closing of the reversing valve according to the state of charge of the power system, thereby changing the direction of exhaust gas flow.

[0044] The specific control content based on the state of charge includes the following:

[0045] 1. If the electrical system has a high state of charge, most of the driving force comes from the electric motor, with the engine playing an auxiliary role. The PLC controller controls the opening and closing of the reversing valve, the first exhaust pipe is closed, and all exhaust gas enters the second exhaust pipe. The exhaust gas then flows into the turbocharger, driving the compressor coaxially linked with it to perform turbocharging. Because the engine is operating in a high state of charge state, it will not operate under high load at this time (see...). Figure 2 ).

[0046] 2. If the battery's state of charge is low, the PLC controller controls the opening and closing of the reversing valve, closing the second exhaust pipe and allowing all exhaust gas to enter the first exhaust pipe, driving the power turbine to rotate. Subsequently, the generator coaxially connected to the turbine rotates to generate electricity. Under this condition, because the driving force required by the car increases, the engine will undergo a transition from a low-load to a high-load operating state (see...). Figure 3 ).

[0047] like Figure 4 As shown, both the power turbine and the booster turbine are variable geometry turbines, including a vortex housing 13 and multiple sets of geometrically variable blades evenly spaced along the circumference of the rotating shaft installed in the vortex housing. Each set of geometrically variable blades includes a main blade 14 and an auxiliary blade 15. The main blade has a cavity inside and an opening 16 on its top surface that communicates with the cavity. The auxiliary blade is embedded in the cavity and is extended and limited by an elastic limiting mechanism.

[0048] In some optional implementations, the elastic limiting mechanism includes a limiting bracket 17 and a limiting spring 18. The limiting bracket is fixed to the bottom of the auxiliary blade, and lower limiting posts 19 are symmetrically arranged on the top of both sides. Upper limiting posts 20 are symmetrically arranged on both sides of the opening of the main blade. The upper and lower limiting posts are symmetrically arranged in pairs. There are two limiting springs, and the upper and lower ends of each limiting spring are respectively fitted and positioned with the upper and lower limiting posts on the corresponding sides.

[0049] This invention integrates the operating modes of the aforementioned hybrid electric vehicle under two different working conditions. During the transition from low to high engine load, the flow rate and velocity of exhaust gases also change. A variable geometry turbine can more efficiently recover energy from the exhaust gases. The turbine's operating mode is as follows:

[0050] (1) When the car engine is operating at low load, the amount of exhaust gas is small. Only the auxiliary blades of the variable geometry turbine extend out under the interaction of spring force and gravity, while the rest of the blades remain in the cavity of the main blades. This results in a larger gap in the entire variable geometry turbine, reducing the resistance to exhaust gas when the engine starts to work.

[0051] (2) During the process of the car engine changing from low load to high load, the exhaust gas velocity and flow rate will increase. The turbine speed may not be able to match its centrifugal force. At this time, the larger exhaust gas flow rate causes the variable geometry turbine to rotate and generate centrifugal force. The limiting spring between the main blade and the secondary blade will be compressed, and the secondary blade will extend to obtain greater torque to meet the turbine to work at the best efficiency. At the same time, because the extension of the secondary blade is coordinated and matched with the turbine speed, the variable geometry turbine still leaves a part of the gap so that the exhaust gas resistance will not be too large.

[0052] (3) When the car engine is working at full load, the exhaust gas flow reaches its maximum value. At this time, the auxiliary blades of the variable geometry turbine are fully extended, and the upper and lower limit posts are in contact, thereby obtaining the designed maximum torque and driving the generator to generate more electrical energy.

[0053] (4) When the car completes the climbing or rapid acceleration and requires a large driving force, the engine stops working, the turbine speed will gradually decrease over time, and its centrifugal force will also decrease. At this time, the limit spring slowly restores its deformation and retracts the auxiliary blade into the cavity, thereby reducing the blade area and the resistance to exhaust gas will decrease accordingly, thereby adjusting the speed and ensuring that the turbine rotates in the best working state.

[0054] When the engine of a hybrid vehicle is running, the exhaust gas drives the generator to generate electricity through the power turbine, while the vehicle's battery is being charged. When the state of charge (SOC) value is greater than 0.8, the charge sensor sends a signal to the PLC controller, and the reversing valve controls the first exhaust gas pipe to close. At this time, the generator stops generating electricity to prevent excessive regenerative braking energy from burning out the battery during braking. The excess exhaust gas enters the second exhaust gas pipe to continue turbocharging.

Claims

1. A hybrid vehicle exhaust energy recovery device based on a variable geometry turbine, characterized by, The application relates to a waste gas power generation and storage unit, a waste gas supercharging unit and a control unit, wherein the waste gas power generation and storage unit comprises a first waste gas pipeline, a power turbine and an electric energy system; the waste gas supercharging unit comprises a second waste gas pipeline, a supercharging turbine and a compressor; the control unit comprises an electric quantity sensor, a PLC controller and a reversing valve; the air inlets of the first waste gas pipeline and the second waste gas pipeline are connected with a main exhaust pipeline; the reversing valve is arranged on the main exhaust pipeline and corresponds to the first waste gas pipeline and the second waste gas pipeline; the power turbine and the supercharging turbine are arranged on the first waste gas pipeline and the second waste gas pipeline respectively; the power turbine is connected with the electric energy system; the supercharging turbine is connected with the compressor; the input end of the PLC controller is electrically connected with the electric quantity sensor; the output end of the PLC controller is electrically connected with the reversing valve; the electric quantity sensor is connected with the electric energy system; the power turbine and the supercharging turbine are variable geometry turbines; the electric energy system comprises a generator, an inverter, a filter and a storage battery which are connected in sequence; the power turbine is coaxially connected with the generator; the electric quantity sensor measures the state of charge of the storage battery; the variable geometry turbine comprises a volute and a plurality of groups of geometrically variable blades which are uniformly and spacedly arranged along the circumferential direction of the volute; each group of the geometrically variable blades comprises a main blade and a secondary blade; the main blade is internally provided with a cavity, the top surface of the main blade is provided with an opening which is connected with the cavity, and the secondary blade is embedded in the cavity and is limited in extension by an elastic limiting mechanism; the elastic limiting mechanism comprises a limiting support and a limiting spring; the limiting support is fixed to the bottom of the secondary blade; the limiting support is provided with a lower limiting column on the top of the two sides; the main blade is provided with an upper limiting column in the cavity on the two sides of the opening; the upper limiting columns and the lower limiting columns are symmetrically arranged in pairs; and the limiting spring is provided with two limiting springs, and the upper and lower ends of each limiting spring are sleeved with the corresponding upper and lower limiting columns.

2. The control method for the exhaust energy recovery device for a hybrid vehicle based on a variable geometry turbine according to claim 1, characterized by The application further relates to a control method of the waste gas power generation and storage unit, the waste gas supercharging unit and the control unit. S1) when the hybrid electric vehicle starts and drives at a low speed, the required driving force is small, and the electric motor provides the required driving force; S2) when the hybrid electric vehicle drives under the conditions of rapid acceleration and climbing, the required driving force is large, the electric quantity sensor installed on the storage battery collects the state of charge and sends the signal to the PLC controller, the opening and closing of the reversing valve is controlled according to the state of charge of the electric energy system, and the waste gas flow direction is changed.

3. The control method of the variable-geometry turbine-based hybrid vehicle exhaust energy recovery device according to claim 2, characterized by, S21) if the state of charge of the electric energy system is high, most of the driving force is provided by the electric motor, the engine plays an auxiliary role, the PLC controller controls the opening and closing degree of the reversing valve, the first waste gas pipeline is closed, the waste gas enters the second waste gas pipeline, the waste gas flows into the supercharging turbine, the compressor which is coaxially connected with the supercharging turbine is driven to work, turbocharging is carried out, and the engine does not work under high load because the engine works under the condition of high state of charge. ​ S22)If the battery state of charge is low, the PLC controller controls the opening and closing degree of the reversing valve, the second exhaust pipe is closed, and the exhaust gas enters the first exhaust pipe entirely, driving the power turbine to rotate, and then the generator coaxially connected with the power turbine rotates to generate electricity. In this working condition, since the driving force required by the automobile increases, the engine will experience a transition from low load to high load working state.

4. The method of operating a variable geometry turbine of a hybrid vehicle exhaust energy recovery device based on a variable geometry turbine according to claim 3, characterized in that, The method comprises the following steps: S1)When the automobile engine is in low load operation, the amount of exhaust gas is small at this time, and only the secondary blades of the variable geometry turbine are partially extended under the interaction of spring force and gravity, and the remaining blades are partially left in the main blade cavity, so that the entire variable geometry turbine leaves a larger gap, reducing the resistance of the engine to exhaust gas at the beginning of work; S2)During the process of changing from low load to high load of the automobile engine, the exhaust gas flow rate and flow rate will increase, and the rotational speed of the turbine may not match its centrifugal force. At this time, the larger exhaust gas flow rate makes the variable geometry turbine rotate to generate centrifugal force, and the limiting spring between the main blade and the secondary blade will be compressed, and the secondary blade will be extended to obtain greater torque to meet the turbine working at the best efficiency. At the same time, because the extension of the secondary blade is matched with the rotational speed of the turbine, the variable geometry turbine still leaves a part of the gap, so that the exhaust gas resistance will not be too large; S3)When the automobile engine is in full load operation, the exhaust gas flow rate reaches the maximum value, at this time, the secondary blades of the variable geometry turbine are completely extended, and the upper and lower limiting columns are in contact, thereby obtaining the designed maximum torque to drive the generator to generate more electric energy; S4)When the automobile completes the climbing or requires a large driving force, the engine stops working, the rotational speed of the turbine will gradually decrease with time, and its centrifugal force will also decrease. At this time, the limiting spring slowly recovers the deformation to retract the secondary blades into the cavity, thereby reducing the blade area and the resistance of the exhaust gas, thereby adjusting the rotational speed to ensure that the turbine rotates at the best working state.

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