Supercharging system for driving engine to realize high-pressure exhaust gas recirculation and control method thereof

Abstract

The invention belongs to the technical field of turbochargers, and discloses a supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation and a control method thereof.The system comprises the engine, the air inlet end of the engine communicates with a supercharging air inlet pipeline, and the air outlet end of the engine communicates with an exhaust pipeline; the other end of the supercharging air inlet pipeline and the other end of the exhaust pipeline are communicated with turbochargers respectively, an exhaust gas recirculation supercharging pipeline is further communicated between the supercharging air inlet pipeline and the exhaust pipeline, and the exhaust gas recirculation supercharging pipeline and the turbochargers are arranged in parallel. The exhaust gas recirculation pressurization pipeline is driven by the exhaust gas exhausted by the exhaust pipeline and pressurizes a part of the exhaust gas again, so that the pressure Pee of the exhaust gas exhausted by the exhaust gas recirculation pressurization pipeline is larger than or equal to the pressure Pc of the pressurized gas in the pressurization gas inlet pipeline; circulating waste gas normally flows into the gas inlet end of the engine, and the waste gas is recycled; the pressure of waste gas exhausted by the engine can be increased again, and then the waste gas is conveyed to the gas inlet end of the engine to participate in combustion.

Description

Technical Field

[0001] The present invention belongs to the technical field of engine turbochargers, and in particular relates to a supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation and a control method thereof. Background Art

[0002] The engine uses an exhaust gas turbocharger to provide more compressed air to the engine, allowing more fuel to be injected into the engine for combustion while keeping the cylinder volume unchanged, thereby generating higher power per liter. At the same time, by allowing more clean air to enter through boost pressure, the combustion in the cylinder can be improved, the emission of pollutants such as soot and carbon monoxide can be reduced, and the combustion efficiency in the cylinder can be improved. While increasing the engine power, the fuel economy of the engine can be improved, and the emission of harmful substances in the exhaust gas discharged by the engine due to incomplete combustion can be reduced.

[0003] From the perspective of fuel economy and power, the highest engine efficiency is desired. However, from an emissions perspective, high-efficiency combustion in an engine can lead to increased nitrogen oxide emissions due to high temperatures and oxygen enrichment. Therefore, how to effectively control high-efficiency engines to reduce nitrogen oxide emissions has become a key focus of modern engine research. Currently, the industry generally adopts two technical approaches to meet these requirements. One is the use of a high-efficiency SCR (Selective Catalytic Reduction) system. This technical approach prioritizes efficient engine combustion to ensure optimal power and economy. The exhaust gas after combustion is then introduced into the SCR system for catalytic reduction, converting pollutants (nitrogen oxides) in the exhaust into pollution-free nitrogen and water, thereby ensuring that the residual nitrogen oxides in the engine exhaust meet emission standards. This approach is simple and efficient (theoretically achieving over 95%), and requires minimal changes to the engine's internal structure. However, it requires the engine to be filled with approximately 5%-10% urea solution while consuming normal fuel, which directly increases operating costs and also brings some reliability issues caused by the catalytic reduction device.

[0004] In addition to the above technical routes, in order to meet the emission index requirements, another technical route is to adopt EGR (exhaust gas recirculation) technology, which directly introduces part of the gas in the engine exhaust into the engine's intake duct, and utilizes the large specific heat capacity of the multi-atomic structure in the engine exhaust gas to reduce the maximum combustion temperature of the engine combustion chamber and reduce the amount of pure air entering the intake duct, thereby controlling the generation of high-temperature, oxygen-rich operating environment. While taking care of the engine power, it controls the emission of nitrogen oxides from the perspective of in-engine combustion. This technology is widely used in engines with National 5 and above emission standards because of its low application cost, low maintenance cost, mature and reliable technology. With the implementation of National 6B emission regulations, this technology has a trend of comprehensive coverage and application.

[0005] likeFigure 1-2 As shown, current EGR technology (exhaust gas recirculation technology) basically adopts high-pressure cycle EGR. This structure directly takes a portion of exhaust gas (approximately 5%-25%) from the exhaust pipe 15 at the front end of the supercharger turbine, reduces the temperature of the introduced exhaust gas through the EGR valve 18 and EGR intercooler 19, and then enters the engine's supercharged intake pipe 4. There, it mixes with the compressed air from the turbocharger 5 and enters the engine cylinder 17 together for combustion and work.

[0006] To achieve this circulation, the pressure Pt in the EGR front pipe 21 before connecting to the EGR valve 18 needs to be greater than the pressure Pc in the EGR rear pipe 20, so that the normal flow of exhaust gas taken by EGR (exhaust gas recirculation) can be achieved. This application requirement requires a higher inlet pressure (Pt) at the front end of the turbine of the turbocharger 5. For the engine, the exhaust resistance increases. At the same time, the compressor of the turbocharger 5 cannot generate too high a boost pressure (Pc). These requirements are not conducive to the efficient operation of the turbocharger 5, nor are they conducive to the efficient combustion and power output of the engine 1.

[0007] In order to meet the application boundary of the above-mentioned high-pressure cycle EGR (Pt>Pc), in actual application, the cross-section of the volute of the turbocharger 5 is continuously reduced to ensure a relatively high pre-turbulence pressure Pt. At the same time, the exhaust gas bypass structure of the turbocharger is used to limit the rotation speed of the turbocharger 5, and combined with the design of the compressor impeller boost characteristics, a lower post-boost pressure Pc is obtained, thereby achieving EGR recirculation. Such structural characteristics lead to excessive pumping losses after the engine works, resulting in a decrease in engine efficiency. For a single turbocharger, the pre-turbulence pressure is lower than the post-boost pressure (Pt>Pc), which will also cause a decrease in the efficiency of the turbocharger 5. The above-mentioned problems will directly lead to a decrease in the efficiency of the engine and turbocharger 5, an increase in fuel consumption, and an increase in heat load. Summary of the Invention

[0008] The main technical problem to be solved by the present invention is to provide a supercharging system and a control method thereof for driving the engine to achieve high-pressure exhaust gas recirculation; around the application boundary requirement that the pre-turbulence pressure is higher than the post-supercharging pressure (Pt>Pc) in the high-pressure circulation EGR process, a supercharging system and a control method thereof are designed on the engine to drive the engine exhaust pressure to increase and achieve high-pressure exhaust gas recirculation. The system can ensure that the operation of the engine and the turbocharger is not limited by the pressure before and after the EGR valve, and the engine and the turbocharger are always maintained in the high-efficiency working area; by separately designing the exhaust gas recirculation supercharger and the control pipeline, the pressure of the exhaust gas introduced into the EGR valve can be further increased, so that the introduced flow can be flexibly controlled.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions: A supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation includes an engine, an intake end of the engine is connected to a supercharging intake pipe, an outlet end of the engine is connected to an exhaust pipe, the other ends of the supercharging intake pipe and the exhaust pipe are respectively connected to a turbocharger, and an exhaust gas recirculation supercharging pipeline is also connected between the supercharging intake pipe and the exhaust pipe. The exhaust gas recirculation supercharging pipeline is arranged in parallel with the turbocharger, and the exhaust gas recirculation supercharging pipeline is driven by the exhaust gas discharged from the exhaust pipe and a part of the exhaust gas is supercharged again, so that the exhaust gas pressure Peco discharged from the exhaust gas recirculation supercharging pipeline is ≥ the supercharged gas pressure Pc in the supercharging intake pipe; the circulating exhaust gas is allowed to flow normally into the intake end of the engine, and the exhaust gas is recycled.

[0010] The following is a further optimization of the above technical solution by the present invention: The exhaust gas recirculation supercharger pipeline includes an exhaust gas recirculation supercharger. The compressor of the exhaust gas recirculation supercharger is connected to the exhaust pipe and the supercharged air intake pipe through the compression pipeline. The turbine of the exhaust gas recirculation supercharger is connected to the exhaust pipe and the exhaust gas discharge pipe through the exhaust pipeline.

[0011] Further optimization: The turbine of the exhaust gas recirculation supercharger is provided with a circulating turbine outlet and a circulating turbine inlet, the compressed air pipeline includes a turbine inlet pipe, one end of the turbine inlet pipe is connected to the circulating turbine inlet, the other end of the turbine inlet pipe is connected to a circulating gas connecting pipe, the air inlet end of the circulating gas connecting pipe is connected to the exhaust pipe; the circulating turbine outlet is connected to a turbine outlet pipe, the other end of the turbine outlet pipe is connected to the exhaust gas discharge pipe.

[0012] Further optimization: A turbine inlet regulating valve is connected in series on the turbine inlet pipe at a position close to the circulating gas connecting pipe, and the turbine inlet regulating valve is used to adjust the flow rate of exhaust gas in the turbine inlet pipe.

[0013] Further optimization: The compressor of the exhaust gas recirculation turbocharger is provided with a circulating compressor air inlet and a circulating compressor air outlet. The exhaust pipeline includes a compressor inlet pipe. One end of the compressor inlet pipe is connected to the circulating compressor air inlet, and the other end of the compressor inlet pipe is connected to the circulating gas connecting pipe. The turbine inlet pipe and the compressor inlet pipe are arranged in parallel.

[0014] Further optimization: A circulating gas inlet regulating valve and a circulating gas intercooler are connected in series along the flow direction of the exhaust gas on the compressor inlet pipe; the circulating gas inlet regulating valve is used to control the flow of the circulating exhaust gas participating in combustion flowing through the compressor inlet pipe.

[0015] Further optimization: the circulating compressor outlet is connected to a supercharged air intake pipe, the other end of the supercharged air intake pipe is connected to a supercharged air intake pipeline, and a supercharged air intake pipeline is connected in series with a supercharged intercooler.

[0016] Further optimization: The exhaust gas recirculation boosting pipeline includes an exhaust gas supercharger. The overall structure of the exhaust gas supercharger includes a compressor and a drive actuator. The power output end of the drive actuator is connected to the compressor transmission. The air inlet of the compressor is connected to the compressor inlet pipe, and the other end of the compressor inlet pipe is connected to the exhaust pipe. The compressor inlet pipe is connected in series with a circulating gas inlet regulating valve and a circulating gas intercooler along the flow direction of the exhaust gas; the air outlet of the compressor is connected to a boosted rear intake pipe, and the other end of the boosted rear intake pipe is connected to the boosted intake pipe.

[0017] Further optimization: an exhaust gas recycling compressor is also integrated on the turbocharger, and the drive shaft of the turbocharger is connected to the exhaust gas recycling compressor in a transmission manner. The air inlet of the exhaust gas recycling compressor is connected to the compressor inlet pipe, and the other end of the compressor inlet pipe is connected to the exhaust pipe. The circulating gas inlet regulating valve and the circulating gas intercooler are connected in series along the flow direction of the exhaust gas on the compressor inlet pipe; the air outlet of the exhaust gas recycling compressor is connected to the supercharged rear intake pipe, and the other end of the supercharged rear intake pipe is connected to the supercharged intake pipe.

[0018] The present invention further provides a control method for a supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation, based on the above-mentioned supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation, comprising the following steps: During engine startup, part of the exhaust gas in the exhaust pipe enters the circulating gas connecting pipe, and then enters the turbine inlet pipe and the compressor inlet pipe respectively. The initial pressures of the exhaust gas are both the exhaust gas pressure value Pt of the engine exhaust. S2. The high-temperature exhaust gas entering the turbine inlet pipe is flow-regulated by the turbine inlet regulating valve. The high-temperature exhaust gas flows unidirectionally in the turbine inlet pipe, enters the circulating turbine inlet, and drives the turbine in the exhaust gas recirculation supercharger to rotate at high speed; S3. The high-temperature exhaust gas entering the compressor inlet pipe is flow-regulated and controlled by the recycle gas inlet regulating valve. The high-temperature exhaust gas first passes through the recycle gas intercooler to cool down and control the temperature to below 200°C. Then, it is unidirectionally guided through the compressor inlet pipe to the recycle compressor inlet. At this time, the recycle exhaust gas is compressed and boosted by the compressor of the exhaust gas recirculation supercharger, and then discharged from the recycle compressor outlet. After being guided by the post-supercharged intake pipe and cooled, it is guided to the supercharged intake pipe and finally enters the engine to participate in combustion.

[0019] The present invention adopts the above technical solution, which has at least the following beneficial effects: 1. The present invention innovatively designs and develops a supercharger that is independently driven to achieve exhaust gas recirculation, breaking the boundary limitation of the traditional EGR valve (exhaust gas recirculation valve) that the pre-turbulence pressure Pt required for operation is greater than the post-supercharge pressure Pc.

[0020] 2. The present invention adopts an independent exhaust gas recirculation supercharger structure, which can effectively maintain the engine and the traditional turbocharger operating in a high-efficiency area, solving the contradiction between engine emission control and fuel economy reduction.

[0021] 3. The independent exhaust gas recirculation supercharger in the present invention controls the flow rate and temperature of the circulating exhaust gas in the exhaust pipe, and then enters the compressor of the exhaust gas recirculation supercharger to increase its pressure. It is then mixed with the air in the supercharged intake pipe to participate in the combustion in the cylinder. The compressor of the exhaust gas recirculation supercharger can adopt an independent structure compressor or be integrated into a turbocharger to achieve this function using a one-vortex dual-compression structure.

[0022] 4. The independent exhaust gas recirculation supercharger in the present invention can adopt an independent turbine structure, a motor-driven or mechanically driven structure, or a single-vortex dual-pressure structure to drive the rotation of the exhaust gas recirculation compressor. The structure and control are flexible and changeable, and are suitable for multiple application scenarios.

[0023] 5. The independent exhaust gas recirculation supercharger of the present invention adopts a motor-driven or one-vortex dual-pressure structure, which can effectively reduce the number of connecting pipes and reduce the complexity of the system.

[0024] 6. At the compressor end of the independent exhaust gas recirculation turbocharger in the present invention, a recirculating gas intercooler is required at the recirculating gas inlet to effectively control the inlet temperature. The outlet can be equipped with an independent post-supercharge intercooler, or it can share the engine's supercharge intercooler to reduce system complexity and control production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the installation structure of the engine and the supercharger in the background technology; Figure 2 This is a diagram of the installation structure of the EGR valve (exhaust gas recirculation technology) in the background technology; Figure 3 This is a diagram of the installation structure of the exhaust gas recirculation and pressurization pipeline in Example 1 of the present invention; Figure 4 This is a diagram of the installation structure of the intercooler without supercharging in Example 1 of the present invention; Figure 5 This is a diagram of the installation structure of the exhaust gas supercharger used in Example 2 of the present invention; Figure 6This is a schematic structural diagram of the exhaust gas recirculation supercharger compressor integrated on the turbocharger in Example 3 of the present invention.

[0026] In the figure: 1-engine; 2-intake manifold; 3-supercharger intercooler; 4-supercharger intake duct; 5-turbocharger; 6-compressor outlet; 7-compressor inlet; 8-air intake duct; 9-air filter; 10-muffler; 11-aftertreatment device; 12-exhaust pipe; 13-turbine outlet; 14-turbine inlet; 15-exhaust duct; 16-exhaust manifold; 17-engine cylinder; 18-EGR valve; 19-EGR intercooler; 20-EGR rear duct; 21-EGR front duct; 22-supercharger After-compression intercooler; 23-air intake pipe after supercharging; 24-recycle compressor inlet; 25-recycle compressor outlet; 26-exhaust gas recirculation supercharger; 27-turbine outlet pipe; 28-recycle turbine outlet; 29-recycle turbine inlet; 30-turbine inlet pipe; 31-turbine inlet regulating valve; 32-recycle gas connecting pipe; 33-recycle gas intercooler; 34-recycle gas inlet regulating valve; 35-exhaust gas supercharger; 36-drive actuator; 40-exhaust gas recycling compressor; 42-drive shaft; 43-compressor inlet pipe. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work shall fall within the scope of protection of the present invention.

[0028] like Figure 1-4 As shown: A boosting system for driving an engine to achieve high-pressure exhaust gas recirculation, including an engine 1, the intake end of the engine 1 is connected to a boosting intake pipe 4, the outlet end of the engine 1 is connected to an exhaust pipe 15, the other ends of the boosting intake pipe 4 and the exhaust pipe 15 are respectively connected to a turbocharger 5, and an exhaust gas recirculation boosting pipeline is also connected between the boosting intake pipe 4 and the exhaust pipe 15, the exhaust gas recirculation boosting pipeline is arranged in parallel with the turbocharger 5, and the exhaust gas recirculation boosting pipeline is driven by the exhaust gas discharged from the exhaust pipe 15 and a part of the exhaust gas is boosted again, so that the exhaust gas pressure Peco discharged from the exhaust gas recirculation boosting pipeline is ≥ the boost gas pressure Pc in the boosting intake pipe 4; the circulating exhaust gas flows normally into the intake end of the engine 1, and the exhaust gas is recycled.

[0029] In this embodiment, the turbocharger 5 is of existing technology and has an integral structure, including a compressor and a turbine. The rotor shafts of the compressor and the turbine are connected in a transmission manner. When in use, the exhaust gas discharged by the engine 1 enters the turbine end of the turbocharger 5 to drive the turbocharger 5 to work. At this time, the compressor of the turbocharger 5 is used to draw fresh air from the outside into the compressor and supercharge it before delivering it to the supercharged intake duct 4.

[0030] In the embodiment, a compressor of the turbocharger 5 is provided with a compressor outlet 6 and a compressor inlet 7, one end of the boost intake pipe 4 is connected to the compressor outlet 6, a boost intercooler 3 is connected in series to the boost intake pipe 4, and the other end of the boost intake pipe 4 is connected to the intake manifold 2, and the intake manifold 2 is connected to the intake end of the engine 1 through the intake manifold.

[0031] The compressor air inlet 7 is connected to an air intake pipe 8, and an air filter 9 is connected in series to the air intake pipe 8. The air intake pipe 8 is used to draw fresh air from outside into the compressor of the turbocharger 5, and the air filter 9 is used to filter the air.

[0032] In this embodiment, the turbine of the turbocharger 5 has a turbine outlet 13 and a turbine inlet 14, one end of the exhaust pipe 15 is connected to the turbine inlet 14, and the other end of the exhaust pipe 15 is connected to the exhaust manifold 16, and the exhaust manifold 16 is connected to the exhaust end of the engine 1 through the exhaust manifold.

[0033] The turbine outlet 13 is connected to an exhaust gas discharge pipe 12, and the exhaust gas discharge pipe 12 is connected in series with a post-processing device 11 and a muffler 10 along the flow direction of the exhaust gas. The post-processing device 11 is used to further process the exhaust gas, and the muffler 10 is used to muffle the exhaust gas to reduce noise pollution; the exhaust gas discharged from the exhaust gas discharge pipe 12 is constrained and processed by the post-processing device 11 and the muffler 10, and finally enters the atmosphere with the exhaust gas.

[0034] In this embodiment 1, the exhaust gas recirculation boosting pipeline includes an exhaust gas recirculation supercharger 26, the compressor of the exhaust gas recirculation supercharger 26 is connected to the exhaust pipe 15 and the boost intake pipe 4 through the compression pipeline, and the turbine of the exhaust gas recirculation supercharger 26 is connected to the exhaust pipe 15 and the exhaust gas discharge pipe 12 through the exhaust pipeline.

[0035] With this design, the exhaust gas discharged by the engine 1 is divided into three paths after passing through the exhaust pipe 15, most of which directly enters the turbine of the turbocharger 5; the other two small parts of exhaust gas enter the compressor and turbine of the exhaust gas recirculation supercharger 26 through the compressor line and the exhaust line respectively. At this time, this part of the exhaust gas is used to drive the turbine to work, and the exhaust gas at the turbine air inlet 14 does not need to be intercooled to dissipate heat. Its thermal energy and kinetic energy are used to drive the turbine to rotate, and drive the coaxial compressor to rotate synchronously, thereby achieving supercharging of the exhaust gas at the compressor air inlet, increasing the exhaust gas pressure, and ensuring the realization of the exhaust gas recirculation demand.

[0036] The turbine of the exhaust gas recirculation supercharger 26 is provided with a circulation turbine outlet 28 and a circulation turbine inlet 29. The compressed air pipeline includes a turbine inlet pipe 30. One end of the turbine inlet pipe 30 is connected to the circulation turbine inlet 29. The other end of the turbine inlet pipe 30 is connected to a circulation gas connecting pipe 32. The air inlet end of the circulation gas connecting pipe 32 is connected to the exhaust pipe 15.

[0037] A turbine inlet regulating valve 31 is connected in series to the turbine inlet pipe 30 at a position close to the circulating gas connecting pipe 32 . The turbine inlet regulating valve 31 is used to regulate the flow rate of the exhaust gas in the turbine inlet pipe 30 .

[0038] The circulating turbine outlet 28 is connected to a turbine outlet pipe 27 , and the other end of the turbine outlet pipe 27 is connected to the exhaust gas discharge pipe 12 .

[0039] In this embodiment, the turbine inlet regulating valve 31 is used to control the flow of exhaust gas flowing through the turbine inlet pipe 30 and entering the circulating turbine inlet 29, and its maximum flow rate is approximately 1 / 5 of the total flow rate of exhaust gas discharged from the exhaust pipe 15; this part of the exhaust gas enters the turbine of the exhaust gas recirculation supercharger 26 and drives the turbine to do work, then flows out through the circulating turbine outlet 28, and enters the exhaust gas exhaust pipe 12 through the turbine outlet pipe 27, and then passes through the post-processing device 11 and the muffler 10 for restraint processing, and finally enters the atmosphere with the exhaust gas.

[0040] With this design, the exhaust gas pressure Pt in the exhaust pipe 15 is equal to the circulating gas pressure in the circulating gas connecting pipe 32, equal to the gas pressure in the turbine inlet pipe 30, and equal to the inlet pressure Peti of the circulating turbine inlet 29. The pressure energy and heat energy in this part of the gas cause the rotor in the exhaust gas recirculation supercharger 26 to rotate at high speed.

[0041] The compressor of the exhaust gas recirculation supercharger 26 is provided with a circulating compressor air inlet 24 and a circulating compressor air outlet 25. The exhaust pipeline includes a compressor inlet pipe 43. One end of the compressor inlet pipe 43 is connected to the circulating compressor air inlet 24, and the other end of the compressor inlet pipe 43 is connected to the circulating gas connecting pipe 32. The turbine inlet pipe 30 and the compressor inlet pipe 43 are arranged in parallel.

[0042] The compressor inlet pipe 43 is connected in series with a recycle gas inlet regulating valve 34 and a recycle gas intercooler 33 in the direction of exhaust gas flow.

[0043] The circulating gas inlet regulating valve 34 controls the flow of the circulating exhaust gas participating in the combustion through the compressor inlet pipe 43. Its maximum flow rate is approximately 1 / 5 of the total flow rate of the exhaust gas discharged from the exhaust pipe 15. In order to better control the characteristics of this part of the circulating gas, an independent circulating gas intercooler 33 is provided after the circulating gas inlet regulating valve 34 to cool the introduced high-temperature circulating gas. The cooled circulating gas enters the circulating compressor inlet 24, is compressed and pressurized by the compressor, and then flows out from the circulating compressor outlet 25.

[0044] The circulating compressor air outlet 25 is connected to a supercharged air intake pipe 23, the other end of which is connected to a supercharged air intake pipe 4. A supercharged air intercooler 22 is connected in series to the supercharged air intake pipe 4. The supercharged air intercooler 22 is used to cool the supercharged circulating gas flowing through the supercharged air intake pipe 23 for easy use.

[0045] With this design, the circulating gas pressure in the compressor inlet pipe 43 is ≈ the exhaust gas pressure Pt in the exhaust pipe 15 (there is some pressure loss when passing through the circulating gas intercooler 33, but the order of magnitude is small), and the pressure of the circulating compressor inlet 24 is the same as the pressure of the compressor inlet pipe 43, that is, the pressure Peci of the circulating compressor inlet 24 is ≈ the exhaust gas pressure Pt of the exhaust pipe 15 ≈ the inlet pressure Peti of the circulating turbine inlet 29, and the initial pressure of the circulating gas entering from the circulating compressor inlet 24 is Peci. At this time, the part of the circulating exhaust gas participating in the combustion is compressed and boosted by the centrifugal compressor of the exhaust gas recirculation supercharger 26, and flows out from the circulating compressor outlet 25 to obtain the circulating gas outlet pressure Peco; at this time, Peco>Peci>Pt, ensuring that Peco≥the supercharged gas pressure Pc in the supercharged intake pipe 4, so that the circulating gas with lower pressure (Pt) in the exhaust pipe 15 is introduced into the supercharged intake pipe 4 with higher pressure (Pc), which is convenient for use.

[0046] In this embodiment, if Figure 4As shown: the supercharged intercooler 22 provided on the supercharged air intake pipe 23 can be simplified and removed, one end of the supercharged air intake pipe 23 is connected to the circulating compressor outlet 25, and the other end of the supercharged air intake pipe 23 is connected to the air inlet of the supercharged intercooler 3 on the supercharged air intake pipe 4. At this time, the supercharged circulating gas coming out of the circulating compressor outlet 25 directly enters the supercharged intercooler 3 for cooling treatment, and then enters the engine 1 to participate in combustion and work.

[0047] In this design, the pressurized recirculated gas (pressure Peco) and the charge air (Pc) share the same intercooler 3, which can simplify the system structure without affecting the ability of the drive recirculated gas to achieve exhaust gas recirculation.

[0048] In summary, the present invention mainly innovatively designs an exhaust gas recirculation supercharger 26 in the middle of the intake and exhaust pipes of the engine 1 to independently drive the exhaust gas discharged by the engine 1 for recycling, breaking the inherent structure of using the traditional EGR valve 18 to achieve exhaust gas recirculation; it realizes the introduction of the lower pressure exhaust gas (Pt) in the exhaust pipe 15 into the higher pressure boost intake pipe 4 (Pc), thereby solving the boundary limitation of the traditional EGR valve 18 structure that must ensure Pt>Pc, and allows both the engine 1 and the turbocharger 5 to operate in a high-efficiency range.

[0049] like Figure 3-Figure 3 As shown, the present invention also provides a control method for a supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation, based on the above-mentioned supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation, comprising the following steps: S1. During the startup and operation of the engine 1, the exhaust gas enters the exhaust pipe 15. Then, most of the exhaust gas is diverted by the exhaust pipe 15 to enter the turbine of the turbocharger 5, driving the rotor to rotate. At this time, the compressor of the turbocharger 5 works synchronously to draw in fresh air from the outside, which is then pressurized and delivered to the air intake of the engine 1 through the boost intake pipe 4 and the intake manifold 2. A portion of the exhaust gas in the exhaust pipe 15 enters the circulating gas connecting pipe 32, and then enters the turbine inlet pipe 30 and the compressor inlet pipe 43 respectively. Their initial pressures are both the exhaust gas pressure value Pt of the engine 1 exhaust.

[0050] S2. The high-temperature exhaust gas entering the turbine inlet pipe 30 is flow-regulated and controlled by the turbine inlet regulating valve 31. The high-temperature exhaust gas flows unidirectionally in the turbine inlet pipe 30, enters the circulating turbine inlet 29 and drives the turbine in the exhaust gas recirculation supercharger 26 to rotate at high speed. When the turbine inlet regulating valve 31 is adjusted, it can be used to control the operating speed of the exhaust gas recirculation supercharger 26.

[0051] S3. The high-temperature exhaust gas entering the compressor inlet pipe 43 is flow-regulated by the recycle gas inlet regulating valve 34. The high-temperature exhaust gas first passes through the recycle gas intercooler 33 to be cooled to below 200°C, and then flows unidirectionally through the compressor inlet pipe 43 to the recycle compressor inlet 24. At this time, the recycle exhaust gas is compressed and boosted by the compressor of the exhaust gas recirculation supercharger 26, and then discharged from the recycle compressor outlet 25. After being guided by the post-supercharged intake pipe 23 and cooled, it is guided to the supercharged intake pipe 4 and finally enters the engine 1 to participate in combustion.

[0052] In step S3, the compressed air involved in combustion in the post-supercharging intake pipe 23 can be directed to the post-supercharging intercooler 22 or the supercharging intercooler 3 for cooling, so as to control the temperature of the compressed air and facilitate use.

[0053] Example 2: Figure 5 As shown, based on the above embodiment 1, in this embodiment 2, the exhaust gas recirculation boosting pipeline can also be used Figure 5 In the structure shown, the exhaust gas recirculation boosting pipeline includes an exhaust gas supercharger 35, which is used to replace the exhaust gas recirculation supercharger 26. The overall structure of the exhaust gas supercharger 35 includes a compressor and a drive actuator 36. The power output end of the drive actuator 36 is transmission-connected to the compressor impeller of the compressor. A circulating compressor air inlet 24 and a circulating compressor air outlet 25 are provided on the compressor casing of the compressor. The circulating compressor air inlet 24 is connected to a compressor inlet pipe 43, and the other end of the compressor inlet pipe 43 is connected to the exhaust pipe 15. A circulating gas inlet regulating valve 34 and a circulating gas intercooler 33 are sequentially connected in series on the compressor inlet pipe 43 along the flow direction of the exhaust gas.

[0054] The circulating compressor air outlet 25 is connected to a supercharged air intake pipe 23 , and the other end of the supercharged air intake pipe 23 is connected to an air intake of a supercharged intercooler 3 on a supercharged air intake pipe 4 .

[0055] In this embodiment, the driving actuator 36 is used to directly drive the compressor of the exhaust gas supercharger 35 to work, and the exhaust gas involved in the combustion is pressurized by the operation of the compressor, which is convenient for use.

[0056] In this embodiment 2, the above-mentioned structure can save the following components: the turbine inlet regulating valve 31, the turbine inlet pipe 30, the turbine of the exhaust gas recirculation supercharger 26 and the turbine outlet pipe 27, making the overall structure simpler and more reliable. At the same time, by driving the actuator 36, more precise and flexible control can be formed. The function of the circulating gas pressurization side is consistent with that of embodiment 1.

[0057] In this embodiment 2, the driving actuator 36 may be a driving motor, and the power output end of the driving motor is drivingly connected to the compressor impeller of the compressor.

[0058] In addition to the present embodiment 2, the driving actuator 36 may be a mechanical pulley, which is connected to a driving pulley via a transmission belt, and the driving pulley may be installed on the rotating shaft of the engine 1 adjacent thereto for use.

[0059] In this second embodiment, when the exhaust gas supercharger 35 is used, the driving actuator 36 is used to directly drive the compressor to operate, without using the recirculated exhaust gas to drive the turbine to drive the compressor to operate. In this case, it is only necessary to adjust the opening of the circulating gas inlet regulating valve 34 to adjust the flow rate of the circulating gas entering the compressor inlet pipe 43. The circulating gas intercooler 33 is used to control the temperature of the circulating gas, and the control operation is simple and accurate. The circulating gas is then supercharged by the compressor and guided to the supercharged intake pipe 4 through the post-supercharging intake pipe 23, and finally enters the engine 1 to participate in combustion.

[0060] Example 3: Figure 6 As shown, based on the above embodiment 1, in this embodiment 3, the overall structure of the turbocharger 5 can also be Figure 6 As shown, an exhaust gas recycling compressor 40 is integrated and installed near the compressor on the turbocharger 5. The drive shaft 42 of the turbocharger 5 is drivingly connected to the compressor impeller of the exhaust gas recycling compressor 40. The air inlet of the exhaust gas recycling compressor 40 is connected to the compressor inlet pipe 43. The other end of the compressor inlet pipe 43 is connected to the exhaust pipe 15. The circulating gas inlet regulating valve 34 and the circulating gas intercooler 33 are connected in series on the compressor inlet pipe 43 along the flow direction of the exhaust gas.

[0061] The air outlet of the exhaust gas recycling compressor 40 is connected to the supercharged air intake pipe 23 , and the other end of the supercharged air intake pipe 23 is connected to the air inlet of the supercharged intercooler 3 on the supercharged air intake pipe 4 .

[0062] In this embodiment, the compressor, turbine and exhaust gas recycling compressor 40 on the turbocharger 5 share a drive shaft 42. The turbine of the turbocharger 5 drives the drive shaft 42 to rotate under the drive of the exhaust gas, and the drive shaft 42 drives the two compressors to work together to compress the air and the circulating exhaust gas to increase the pressure, making the overall structure more simple.

[0063] For those skilled in the art, according to the teachings of the present invention, without departing from the principles and spirit of the present invention, changes, modifications, substitutions and variations made to the implementation methods are still within the scope of protection of the present invention.

Claims

1. A supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation, comprising an engine (1), an air intake end of the engine (1) being connected to a supercharging air intake pipe (4), an air outlet end of the engine (1) being connected to an exhaust pipe (15), and the other ends of the supercharging air intake pipe (4) and the exhaust pipe (15) being respectively connected to a turbocharger (5), characterized in that: An exhaust gas recirculation and supercharging pipeline is also connected between the supercharged air intake pipeline (4) and the exhaust pipeline (15). The exhaust gas recirculation and supercharging pipeline is arranged in parallel with the turbocharger (5), and the exhaust gas recirculation and supercharging pipeline is driven by the exhaust gas discharged from the exhaust pipeline (15) and supercharges a part of the exhaust gas again, so that the exhaust gas pressure Peco discharged from the exhaust gas recirculation and supercharging pipeline is greater than the supercharged gas pressure Pc in the supercharged air intake pipeline (4); the circulating exhaust gas flows normally into the intake end of the engine (1), and the exhaust gas is recycled.

2. The supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation according to claim 1, characterized in that: The exhaust gas recirculation supercharger pipeline includes an exhaust gas recirculation supercharger (26), a compressor of the exhaust gas recirculation supercharger (26) is connected to the exhaust pipe (15) and the supercharged air intake pipe (4) through the compression pipe, and a turbine of the exhaust gas recirculation supercharger (26) is connected to the exhaust pipe (15) and the exhaust gas discharge pipe (12) through the exhaust pipe.

3. The supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation according to claim 2, characterized in that: The turbine of the exhaust gas recirculation supercharger (26) is provided with a circulating turbine outlet (28) and a circulating turbine inlet (29); the compressed air pipeline includes a turbine inlet pipe (30); one end of the turbine inlet pipe (30) is connected to the circulating turbine inlet (29); the other end of the turbine inlet pipe (30) is connected to a circulating gas connecting pipe (32); the air inlet end of the circulating gas connecting pipe (32) is connected to the exhaust pipe (15); the circulating turbine outlet (28) is connected to a turbine outlet pipe (27); the other end of the turbine outlet pipe (27) is connected to the exhaust gas discharge pipe (12).

4. The supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation according to claim 3, characterized in that: A turbine inlet regulating valve (31) is connected in series to a position on the turbine inlet pipe (30) close to the circulating gas connecting pipe (32). The turbine inlet regulating valve (31) is used to regulate the flow rate of the exhaust gas in the turbine inlet pipe (30).

5. The supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation according to claim 4, characterized in that: The compressor of the exhaust gas recirculation supercharger (26) is provided with a circulating compressor air inlet (24) and a circulating compressor air outlet (25), and the exhaust pipeline includes a compressor inlet pipe (43), one end of the compressor inlet pipe (43) is connected to the circulating compressor air inlet (24), and the other end of the compressor inlet pipe (43) is connected to the circulating gas connecting pipe (32), and the turbine inlet pipe (30) and the compressor inlet pipe (43) are arranged in parallel.

6. The supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation according to claim 5, characterized in that: A circulating gas inlet regulating valve (34) and a circulating gas intercooler (33) are connected in series along the flow direction of the exhaust gas on the compressor inlet pipe (43); the circulating gas inlet regulating valve (34) is used to control the flow rate of the circulating exhaust gas participating in combustion flowing through the compressor inlet pipe (43).

7. The supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation according to claim 6, characterized in that: The circulating compressor air outlet (25) is connected to a supercharged air intake pipe (23), the other end of which is connected to a supercharged air intake pipeline (4), and a supercharged air intake intercooler (22) is connected in series to the supercharged air intake pipeline (4).

8. The supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation according to claim 7, characterized in that: The exhaust gas recirculation boosting pipeline includes an exhaust gas supercharger (35). The overall structure of the exhaust gas supercharger (35) includes a compressor and a driving actuator (36). The power output end of the driving actuator (36) is connected to the compressor inlet. The compressor inlet is connected to a compressor inlet pipe (43). The other end of the compressor inlet pipe (43) is connected to the exhaust pipe (15). The compressor inlet pipe (43) is connected in series with a circulating gas inlet regulating valve (34) and a circulating gas intercooler (33) along the flow direction of the exhaust gas. The compressor outlet is connected to a supercharged rear intake pipe (23). The other end of the supercharged rear intake pipe (23) is connected to the supercharged intake pipe (4).

9. The supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation according to claim 8, characterized in that: An exhaust gas recycling compressor (40) is also integrated and installed on the turbocharger (5). The drive shaft (42) of the turbocharger (5) is connected to the exhaust gas recycling compressor (40) in a transmission manner. The air inlet of the exhaust gas recycling compressor (40) is connected to a compressor inlet pipe (43). The other end of the compressor inlet pipe (43) is connected to the exhaust pipe (15). A circulating gas inlet regulating valve (34) and a circulating gas intercooler (33) are connected in series along the flow direction of the exhaust gas. The air outlet of the exhaust gas recycling compressor (40) is connected to a supercharged rear air intake pipe (23). The other end of the supercharged rear air intake pipe (23) is connected to the supercharged air intake pipe (4).

10. A control method for a supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation, based on the supercharging system for driving an engine to achieve high-pressure exhaust gas recirculation according to claim 9, characterized in that: The steps include: S1. During the process of starting the engine (1), a portion of the exhaust gas in the exhaust pipe (15) enters the circulating gas connecting pipe (32), and then enters the turbine inlet pipe (30) and the compressor inlet pipe (43) respectively, and the initial pressures thereof are both the exhaust gas pressure value Pt of the exhaust gas of the engine (1); S2, the high-temperature exhaust gas entering the turbine inlet pipe (30) is flow-regulated and controlled by the turbine inlet regulating valve (31), and the high-temperature exhaust gas flows in one direction in the turbine inlet pipe (30), enters the circulating turbine inlet (29) and drives the turbine in the exhaust gas recirculation supercharger (26) to rotate at high speed; S3. The high-temperature exhaust gas entering the compressor inlet pipe (43) is flow-regulated by the circulating gas inlet regulating valve (34). The high-temperature exhaust gas first passes through the circulating gas intercooler (33) for cooling and lowering the temperature to below 200°C, and then is unidirectionally guided to the circulating compressor inlet (24) through the compressor inlet pipe (43). At this time, the circulating exhaust gas is compressed and pressurized by the compressor of the exhaust gas recirculation supercharger (26), and then discharged from the circulating compressor outlet (25). After being guided by the supercharged intake pipe (23) and cooled, it is guided to the supercharged intake pipe (4), and finally enters the engine (1) to participate in combustion.

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