Hybrid parallel intake supercharging system of two-stroke engine and control method

Abstract

The application discloses a kind of two-stroke engine's hybrid combined type air intake supercharging system and control method, it is related to engine technical field.The system includes air intake pipeline assembly and exhaust pipeline assembly.Air intake pipeline assembly includes air intake pipeline, mechanical supercharger, air intake bypass valve and turbocharger;First air intake supercharging passage of mechanical supercharger and second air intake supercharging passage of turbocharger are in series in air intake pipeline, air intake bypass valve is parallel with first air intake supercharging passage.Exhaust pipeline assembly includes exhaust pipeline and exhaust bypass valve;Exhaust gas drive passage of turbocharger is in series in exhaust pipeline, exhaust bypass valve is parallel with exhaust gas drive passage.The application is controlled by air intake bypass valve and exhaust bypass valve, according to the different operating conditions of engine, realizes the supercharging mode switching in full operating condition range, maintains the differential pressure characteristic of intake and exhaust beneficial to scavenging, avoids the increase of scavenging loss and the decline of scavenging quality.

Description

Technical Field

[0001] This invention relates to the technical field of engines, and in particular to a hybrid intake turbocharging system and control method for a two-stroke engine. Background Technology

[0002] Two-stroke engines are widely used in small aero-piston engines, drones, and other fields due to their simple structure and high power density. However, their inherent drawbacks, such as large scavenging losses and high heat loads, severely limit their application in high-performance scenarios, especially with significant power attenuation at high altitudes. Supercharging technology is an important way to improve their performance, and existing technologies mainly include exhaust gas turbocharging, mechanical supercharging, electric supercharging, and compound supercharging.

[0003] However, all of the above-mentioned single supercharging methods have significant drawbacks when applied to two-stroke engines: exhaust gas turbocharging increases exhaust resistance, reduces the intake and exhaust pressure difference, and severely weakens intake efficiency; mechanical supercharging consumes too much power at high speeds, resulting in a significant decrease in effective power and fuel economy; electric supercharging has problems such as high cost, heavy weight, and difficult maintenance, making it difficult to meet the stringent requirements of the aviation and drone fields.

[0004] To overcome these shortcomings, compound supercharging technology emerged, aiming to achieve complementary advantages by combining multiple supercharging methods. However, in practical applications, the various supercharging units cannot achieve coordinated decoupling according to the rapid operating conditions of a two-stroke engine: at low speeds, the exhaust turbine interferes with the intake and exhaust pressure difference; at high speeds, mechanical supercharging increases power consumption unnecessarily, and the overall transient response is slow and the intake control precision is insufficient, leading to engine instability.

[0005] Therefore, how to achieve efficient coordination and dynamic decoupling of each booster unit under all operating conditions, while taking into account response speed, power efficiency and system cost, is a technical problem that urgently needs to be solved in this field. Summary of the Invention The purpose of this invention is to provide a hybrid intake turbocharging system and control method for a two-stroke engine, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0006] The technical solution adopted to solve the above-mentioned technical problems is as follows: This invention provides a hybrid intake turbocharging system for a two-stroke engine, comprising: An intake piping assembly includes an intake pipe, a supercharger, an intake bypass valve, and a turbocharger. The outlet of the intake pipe is connected to the intake port of the two-stroke engine. The supercharger has a drive wheel system and a first intake boosting channel. The drive wheel system is used to drive the crankshaft of the two-stroke engine. The first intake boosting channel is used to boost the intake air under the drive of the crankshaft. The turbocharger has a second intake boosting channel and an exhaust gas drive channel. The exhaust gas drive channel is used to allow exhaust gas to enter and drive the turbine to rotate. The second intake boosting channel is used to boost the intake air under the drive of the turbine. The first and second intake boosting channels are connected in series in the intake pipe along the intake direction. The intake bypass valve is connected in parallel with the first intake boosting channel, and the intake bypass valve is configured to adjust its opening degree according to the operating conditions of the two-stroke engine. An exhaust piping assembly includes an exhaust pipe and an exhaust bypass valve; the inlet of the exhaust pipe is connected to the exhaust port of the two-stroke engine, and the exhaust gas drive passage is connected in series in the exhaust pipe; the exhaust gas bypass valve is connected in parallel with the exhaust gas drive passage, and the exhaust gas bypass valve is configured to adjust its opening degree according to the operating conditions of the two-stroke engine.

[0007] The beneficial effects of the hybrid intake turbocharger system of the present invention are: This invention, through the coordinated control of the intake bypass valve and the exhaust bypass valve, achieves coordinated boosting and mode switching across the entire operating range of a two-stroke engine, according to different operating conditions. This maintains favorable intake and exhaust pressure differential characteristics for scavenging across the entire operating range, effectively preventing increased scavenging losses and decreased scavenging quality, thereby improving combustion efficiency and reducing emissions. Furthermore, it fully utilizes the complementary advantages of the fast low-speed response of a mechanical supercharger and the high high-speed efficiency of a turbocharger. Through a hybrid structure and bypass control, the boosting system can provide stable and controllable boost pressure across a wide speed range from low to high speeds, while maintaining good transient response characteristics, significantly improving the overall performance of the two-stroke engine under varying operating conditions.

[0008] As a further improvement to the above technical solution, both the intake bypass valve and the exhaust bypass valve are electrically controlled valves and are electrically connected to the electronic control unit in the two-stroke engine.

[0009] As a further improvement to the above technical solution, the electronic control unit is configured as follows: When the two-stroke engine is in the starting condition or low-speed condition, the intake bypass valve is controlled to close and the exhaust bypass valve is controlled to open fully. When the two-stroke engine is in a medium-speed or transient variable operating condition, the opening of the intake bypass valve and the exhaust bypass valve are controlled in real time to keep the intake pressure and intake temperature at the intake port of the two-stroke engine within a first preset pressure range and a first preset temperature range, respectively. When the two-stroke engine is operating at high speed, the intake bypass valve is fully opened, and the opening of the exhaust bypass valve is controlled in real time, so that the intake pressure and intake temperature at the intake port of the two-stroke engine are maintained within the second preset pressure range and the second preset temperature range, respectively.

[0010] As a further improvement to the above technical solution, the intake pipeline assembly also includes an intercooler, which is disposed between the outlet of the second intake boosting channel and the intake port of the two-stroke engine, and is used to cool the boosted intake air.

[0011] As a further improvement to the above technical solution, the intake pipe assembly also includes a first pressure-temperature sensor and a second pressure-temperature sensor. The first pressure-temperature sensor is used to detect the intake pressure and intake temperature at the outlet of the second intake boost channel, and the second pressure-temperature sensor is used to detect the intake pressure and intake temperature at the intake port of the two-stroke engine.

[0012] As a further improvement to the above technical solution, the first pressure and temperature sensor and the second pressure and temperature sensor are respectively electrically connected to the electronic control unit.

[0013] As a further improvement to the above technical solution, the electronic control unit is also configured to control the opening degree of the intake bypass valve and the exhaust bypass valve based on the real-time intake pressure and real-time intake temperature at the inlet of the second intake boost channel and the real-time intake temperature and real-time intake temperature at the intake port of the two-stroke engine.

[0014] As a further improvement to the above technical solution, the mechanical supercharger is provided in two parts, and the first intake supercharging channels of the two mechanical superchargers are connected in parallel in the intake pipe.

[0015] As a further improvement to the above technical solution, the two-stroke engine is a horizontally opposed type, and the two superchargers are arranged symmetrically with respect to the axis of the two-stroke engine.

[0016] This invention also proposes a control method for a hybrid induction turbocharger system, applicable to the aforementioned hybrid induction turbocharger system, the control method comprising the following steps: When the two-stroke engine is in the starting condition or low-speed condition, the intake bypass valve is controlled to close and the exhaust bypass valve is controlled to open fully, so that air flows through the first intake boosting channel and the second intake boosting channel in sequence before entering the two-stroke engine. When the two-stroke engine is in a medium-speed or transient variable operating condition, the opening of the intake bypass valve and the exhaust bypass valve are controlled in real time to allow air to flow sequentially through the first intake boosting channel and the second intake boosting channel before entering the two-stroke engine. At the same time, a portion of the air compressed through the first intake boosting channel is returned to the inlet of the first intake boosting channel through the intake bypass valve, and a portion of the exhaust gas is directly discharged through the exhaust bypass valve, so as to maintain the intake pressure and intake temperature at the intake port of the two-stroke engine within a first preset pressure range and a first preset temperature range, respectively. When the two-stroke engine is operating at high speed, the intake bypass valve is fully opened, and the opening of the exhaust bypass valve is controlled in real time. This allows air to flow sequentially through the intake bypass valve and the second intake boosting channel before entering the two-stroke engine. At the same time, some exhaust gas is directly discharged through the exhaust bypass valve, thereby maintaining the intake pressure and intake temperature at the intake port of the two-stroke engine within the second preset pressure range and the second preset temperature range, respectively.

[0017] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments; Figure 1 This is a schematic diagram of gas flow in a two-stroke engine under startup or low-speed conditions, as provided by the present invention. Figure 2 This is a schematic diagram of the gas flow in a hybrid intake turbocharger system provided by the present invention when the two-stroke engine is in a medium-speed condition or a transient variable condition. Figure 3 This is a schematic diagram of the gas flow in a two-stroke engine operating at high speed, provided by the hybrid intake turbocharging system of the present invention. Figure 4 This is a schematic diagram of the installation of two superchargers in one embodiment of the two-stroke engine provided by the present invention; Figure 5 This is a flowchart of an embodiment of the control method provided by the present invention; Icon labels: Intake piping assembly 100; intake pipe 110; supercharger 120; drive wheel system 121; first intake boost channel 122; intake bypass valve 130; turbocharger 140; second intake boost channel 141; exhaust gas drive channel 142; intercooler 150; first pressure and temperature sensor 160; second pressure and temperature sensor 170; Exhaust piping assembly 200; exhaust pipe 210; waste gas bypass valve 220; 300 two-stroke engine; Electronic control unit 400. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to 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 of this invention.

[0021] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0022] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0024] In view of the difficulties in the coordinated control of the supercharging system and the two-stroke scavenging process in the existing technology, the insufficient supercharging capability and slow transient response under low-speed conditions, as well as the poor optimization of system integration and power-to-weight ratio, the present invention provides a hybrid intake supercharging system for a two-stroke engine 300.

[0025] Reference Figures 1-4The following is an embodiment of a hybrid intake supercharging system for a two-stroke engine 300 according to the present invention: like Figure 1 As shown, the hybrid intake turbocharger system of the present invention includes: an intake manifold assembly 100 and an exhaust manifold assembly 200.

[0026] The intake manifold assembly 100 is used to supply intake air to the two-stroke engine 300. Specifically, the intake manifold assembly 100 includes an intake pipe 110, a supercharger 120, an intake bypass valve 130, and a turbocharger 140.

[0027] like Figure 1 As shown, the outlet of the intake duct 110 is connected to the air intake of the two-stroke engine 300, and the inlet of the intake duct 110 is connected to the outside atmosphere. In some embodiments, an air filter is installed at the inlet of the intake duct 110 to filter the incoming air.

[0028] like Figure 1 As shown, the supercharger 120 is essentially a positive displacement pressure pump that compresses gas through changes in the volume of its internal rotor, achieving a significant boost effect at low speeds. The supercharger 120 includes a drive wheel system 121 and a first intake boosting channel 122. The drive wheel system 121 is connected to the crankshaft of the two-stroke engine 300, and its specific form includes, but is not limited to, a belt pulley system, a gear system, or a sprocket system. The first intake boosting channel 122 is used to boost the intake air under the drive of the crankshaft.

[0029] The turbocharger 140 is a device that uses exhaust gas energy to drive a turbine, which in turn rotates a compressor impeller to achieve intake air boosting. The higher the exhaust gas energy, the more significant the boosting effect. The turbocharger 140 is provided with a second intake boosting channel 141 and an exhaust gas drive channel 142. The exhaust gas drive channel 142 is used to allow exhaust gas to enter and drive the turbine to rotate, while the second intake boosting channel 141 is used to boost the intake air under the drive of the turbine.

[0030] like Figure 1 As shown, in terms of airflow connection, the first intake booster channel 122 and the second intake booster channel 141 are connected in series in the intake duct 110 along the intake direction. The intake bypass valve 130 is connected in parallel with the first intake booster channel 122 and is configured to adjust its opening according to the operating conditions of the two-stroke engine 300. Through this parallel structure, the air boosted by the first intake booster channel 122 can flow back to the inlet of the intake duct 110 along the intake bypass valve 130; or, the air at the inlet of the intake duct 110 can also directly enter the second intake booster channel 141 through the intake bypass valve 130, thereby achieving selective switching of the airflow path.

[0031] The exhaust manifold assembly 200 is used to discharge the exhaust gas from the two-stroke engine 300. The exhaust manifold assembly 200 includes an exhaust pipe 210 and an exhaust bypass valve 220.

[0032] like Figure 1 As shown, the inlet of the exhaust pipe 210 is connected to the exhaust port of the two-stroke engine 300, and the exhaust gas drive passage 142 is connected in series in the exhaust pipe 210; the exhaust gas bypass valve 220 is connected in parallel with the exhaust gas drive passage 142, and the exhaust gas bypass valve 220 is configured to adjust its opening according to the operating conditions of the two-stroke engine 300. Through this parallel structure, the exhaust gas discharged from the two-stroke engine 300 can be directly discharged to the outside through the exhaust gas bypass valve 220 without flowing through the exhaust gas drive passage 142, thereby regulating the exhaust gas flow rate entering the exhaust gas drive passage 142, and thus controlling the output power of the turbocharger 140 and the exhaust back pressure of the two-stroke engine 300.

[0033] Both the intake bypass valve 130 and the exhaust bypass valve 220 are electronically controlled valves and are electrically connected to the electronic control unit 400 (ECU) in the two-stroke engine 300. The ECU 400 is configured to execute the following control strategies: like Figure 1 As shown, when the two-stroke engine 300 is in the starting condition or low-speed condition, the intake bypass valve 130 is closed and the exhaust bypass valve 220 is fully opened. like Figure 2 As shown, when the two-stroke engine 300 is in medium-speed or transient variable operating conditions, the opening of the intake bypass valve 130 and the exhaust bypass valve 220 are controlled in real time to keep the intake pressure and intake temperature at the intake port of the two-stroke engine 300 within the first preset pressure range and the first preset temperature range, respectively. like Figure 3 As shown, when the two-stroke engine 300 is in high-speed operation, the intake bypass valve 130 is fully opened and the opening of the exhaust bypass valve 220 is controlled in real time so that the intake pressure and intake temperature at the intake port of the two-stroke engine 300 are maintained within the second preset pressure range and the second preset temperature range, respectively.

[0034] Through the coordinated control of the intake bypass valve 130 and the exhaust bypass valve 220 described above, the present invention can intelligently switch between the following three operating modes according to different operating conditions of the two-stroke engine 300: Starting or low-speed operation: such as Figure 1As shown, under this operating condition, the exhaust energy is insufficient, and the turbocharger 140 cannot work effectively. At this time, the intake bypass valve 130 is closed, and the exhaust bypass valve 220 is fully opened. The crankshaft directly drives the supercharger 120 to perform primary compression of the intake air, and the second intake boost passage 141 of the turbocharger 140 is used only as an intake passage. This mode effectively compensates for the turbocharger's sluggish response at low speeds, significantly improving low-speed torque and intake capacity.

[0035] Medium-speed or transient variable operating conditions: such as Figure 2 As shown, under this operating condition, the supercharger 120 and turbocharger 140 work together. The system performs real-time closed-loop control of the opening of the intake bypass valve 130 and the exhaust bypass valve 220, ensuring that air enters the two-stroke engine 300 after passing through the primary compression stage of the supercharger 120 and the secondary compression stage of the turbocharger 140. Simultaneously, some of the air after primary compression can flow back to the inlet of the supercharger 120 through the intake bypass valve 130, and some exhaust gas is directly discharged through the exhaust bypass valve 220, thereby precisely regulating the boost pressure and intake air temperature to maintain them within a first preset pressure range and a first preset temperature range. This mode balances transient response speed and high pressure ratio requirements, effectively improving the stability of operation under varying conditions.

[0036] High-speed operating conditions: such as Figure 3 As shown, under this operating condition, the turbocharger 140 enters its high-efficiency operating range, sufficient to independently maintain the high-pressure intake demand. At this time, the intake bypass valve 130 is fully open, allowing fresh air to directly enter the turbocharger 140 for compression, while the supercharger 120 idles, significantly reducing power consumption at high speeds. Simultaneously, the system adjusts the opening of the exhaust bypass valve 220 in real time, maintaining the intake pressure and temperature within the second preset pressure and temperature ranges, avoiding over-boosting and excessive exhaust back pressure.

[0037] Furthermore, such as Figure 1 As shown, the intake manifold assembly 100 also includes an intercooler 150, which is located between the outlet of the second intake boost passage 141 and the intake port of the two-stroke engine 300. The intercooler 150 is used to cool the boosted intake air to reduce the intake air temperature, increase the intake air density, and further improve the combustion efficiency.

[0038] In some preferred embodiments, such as Figure 1 As shown, the intake pipe assembly 100 also includes a first pressure and temperature sensor 160 and a second pressure and temperature sensor 170. Both the first pressure and temperature sensor 160 and the second pressure and temperature sensor 170 are electronic detection devices that integrate pressure-sensitive elements and temperature-sensitive elements, and can monitor the pressure and temperature changes of the gas in real time.

[0039] Specifically, the first pressure and temperature sensor 160 is used to detect the intake pressure and intake temperature at the outlet of the second intake boost channel 141; the second pressure and temperature sensor 170 is used to detect the intake pressure and intake temperature at the intake port of the two-stroke engine 300. The first pressure and temperature sensor 160 and the second pressure and temperature sensor 170 are electrically connected to the electronic control unit 400.

[0040] The electronic control unit 400 is also configured to perform closed-loop control of the opening of the intake bypass valve 130 and the exhaust bypass valve 220 based on the real-time intake pressure and temperature at the outlet of the second intake booster channel 141 and the real-time intake pressure and temperature at the intake port of the two-stroke engine 300. It should be noted that the control of intake pressure and temperature ultimately translates to precise control of the intake airflow, thereby effectively suppressing fluctuations in the circulating intake airflow and enabling the two-stroke engine 300 to achieve a stable operating state.

[0041] In some preferred embodiments, such as Figure 1 As shown, there are two superchargers 120, and the first intake boosting channels 122 of the two superchargers 120 are connected in parallel in the intake pipe 110. During supercharging, the incoming fresh air is evenly distributed to the two superchargers 120 to achieve compound supercharging. This parallel twin-supercharger structure allows for the use of smaller supercharger models, simplifying the system structure, reducing system weight and volume while ensuring overall boosting performance. It also enables compact integration of the supercharging system with the two-stroke engine 300, meeting the needs of high power-to-weight ratio applications, while offering significant cost advantages and facilitating rapid productization.

[0042] Furthermore, such as Figure 4 As shown, the two-stroke engine 300 in this embodiment is a horizontally opposed type, with two superchargers 120 arranged symmetrically with respect to the axis of the two-stroke engine 300. This symmetrical arrangement makes the overall layout more compact and aesthetically pleasing. Furthermore, the dual-parallel structure balances the mass distribution of the entire machine and the driving force of the wheel system, reducing vibrations caused by imbalances in the wheel system's forces. This significantly improves the operational stability of the two-stroke engine 300 and indirectly simplifies the decoupling design of the suspension system, possessing potentially significant economic value.

[0043] In summary, by coordinating the control of the intake bypass valve 130 and the exhaust bypass valve 220, this invention achieves coordinated boosting and mode switching of the two-stroke engine 300 across the entire operating range. This maintains favorable intake and exhaust pressure differential characteristics for scavenging across the entire operating range, effectively avoiding increased scavenging losses and decreased scavenging quality, improving combustion efficiency, and reducing emissions.

[0044] Meanwhile, this invention fully utilizes the complementary advantages of the mechanical supercharger 120's fast low-speed response and the turbocharger 140's high high-speed efficiency. Through a hybrid structure and bypass control, the supercharging system can provide stable and controllable boost pressure over a wide speed range from low to high speeds, while maintaining good transient response characteristics, significantly improving the overall performance of the two-stroke engine 300 under varying operating conditions.

[0045] This invention employs a hybrid supercharging and turbocharging approach, effectively solving the technical problem of increased exhaust resistance and consequently reduced scavenging efficiency caused by the presence of an exhaust turbine. It utilizes the low-speed advantage of the supercharger 120 and the high-speed advantage of the turbocharger 140, respectively. By controlling the switching of the supercharging intake mode and monitoring pressure fluctuations, the two-stroke engine 300 achieves ample power and minimizes energy consumption and optimizes efficiency under all operating conditions.

[0046] Based on the aforementioned hybrid induction turbocharger system, the present invention also provides a control method for the hybrid induction turbocharger system. This method is applicable to the aforementioned hybrid induction turbocharger system, and particularly suitable for system architectures including an electronic control unit 400, a first pressure and temperature sensor 160, and a second pressure and temperature sensor 170.

[0047] The electronic control unit 400 is electrically connected to the intake bypass valve 130, the exhaust bypass valve 220, the first pressure and temperature sensor 160, and the second pressure and temperature sensor 170, respectively. The electronic control unit 400 acquires the operating parameters of the two-stroke engine 300 in real time, including but not limited to the engine speed, load, and throttle opening, and combines the intake pressure and temperature signals fed back by the first and second pressure and temperature sensors 160 and 170 to perform closed-loop control on the opening of the intake bypass valve 130 and the exhaust bypass valve 220, so as to realize mode switching and boost coordination under different operating conditions.

[0048] like Figure 5 As shown, the control method of the present invention will be described in detail below with reference to specific steps.

[0049] The present invention provides a control method for a hybrid intake turbocharger system, comprising the following steps: Step S100: When the two-stroke engine 300 is in the starting condition or low-speed condition, control the intake bypass valve 130 to close and control the exhaust bypass valve 220 to fully open, so that air flows through the first intake boosting channel 122 and the second intake boosting channel 141 in sequence before entering the two-stroke engine 300.

[0050] In this step, when the speed of the two-stroke engine 300 is lower than the first speed threshold, or the load is lower than the first load threshold, it is determined that the two-stroke engine 300 is in a starting or low-speed condition. At this time, the exhaust energy is insufficient, the turbocharger 140 cannot effectively build up boost pressure, and the electronic control unit 400 controls the intake bypass valve 130 to close, while controlling the exhaust bypass valve 220 to open fully.

[0051] The air intake path for this step is as follows: Figure 1 As shown, outside air flows sequentially through the intake pipe 110, the first intake boost passage 122 (the supercharger 120 performs first-stage compression), the second intake boost passage 141 (at this time, the turbocharger 140 is not working effectively, and the second intake boost passage 141 only serves as an airflow passage) and the intercooler 150, and finally enters the two-stroke engine 300.

[0052] The exhaust gas path for this step is as follows: Figure 1 As shown, all the exhaust gas from the two-stroke engine 300 flows through the exhaust bypass valve 220 and is discharged outwards. However, because the two-stroke engine 300 operates at a low speed and has limited exhaust energy, the turbocharger 140 does not provide effective boost.

[0053] The supercharger 120, driven directly by the crankshaft, provides intake boost, effectively compensating for the turbocharger's sluggish response at low speeds, significantly improving low-speed torque and intake capacity, and enhancing starting performance and low-speed stability.

[0054] Step S200: When the two-stroke engine 300 is in a medium-speed or transient variable operating condition, the opening of the intake bypass valve 130 and the exhaust bypass valve 220 is controlled in real time to allow air to flow sequentially through the first intake boosting channel 122 and the second intake boosting channel 141 before entering the two-stroke engine 300. At the same time, some of the air compressed by the first intake boosting channel 122 is returned to the inlet of the first intake boosting channel 122 through the intake bypass valve 130, and some of the exhaust gas is directly discharged through the exhaust bypass valve 220, so as to maintain the intake pressure and intake temperature at the intake port of the two-stroke engine 300 within the first preset pressure range and the first preset temperature range, respectively. In this step, when the speed of the two-stroke engine 300 is between the first speed threshold and the second speed threshold, it is determined that the two-stroke engine 300 is in a medium-speed operating condition; or when the throttle opening change rate is detected to exceed the preset change rate threshold, it is determined to be in a transient variable operating condition. As exhaust energy gradually becomes sufficient, the turbocharger 140 begins to enter its effective operating range. At this time, the electronic control unit 400 performs real-time coordinated closed-loop control of the opening of the intake bypass valve 130 and the exhaust bypass valve 220.

[0055] The electronic control unit 400 receives the following feedback signals in real time: The first pressure and temperature sensor 160 detects the intake pressure P1 and intake temperature T1 at the outlet of the second intake booster channel 141; the second pressure and temperature sensor 170 detects the intake pressure P2 and intake temperature T2 at the intake of the two-stroke engine 300.

[0056] The control targets are to maintain P2 and T2 within the first preset pressure range and the first preset temperature range, respectively.

[0057] When P2 is lower than the lower limit of the first preset pressure range, the electronic control unit 400 reduces the opening of the intake bypass valve 130 (or even closes it completely), allowing more air to flow through the first intake boost channel 122 for primary compression to increase the boost pressure; when P2 is higher than the upper limit of the first preset pressure range, the electronic control unit 400 increases the opening of the intake bypass valve 130, allowing some of the air after primary compression to flow back to the inlet of the first intake boost channel 122 through the intake bypass valve 130 (i.e., forming "return pressure relief"), thereby reducing the gas pressure entering the second intake boost channel 141.

[0058] When P2 is below the lower limit of the first preset pressure range, the electronic control unit 400 reduces the opening of the exhaust bypass valve 220 (or even closes it completely) to allow more exhaust gas to enter the exhaust gas drive channel 142, thereby increasing the turbine speed and boost pressure. When P2 is above the upper limit of the first preset pressure range, the electronic control unit 400 increases the opening of the exhaust bypass valve 220 to allow some exhaust gas to be discharged directly, reducing the turbine driving force and thus reducing the boost pressure.

[0059] When T2 is higher than the upper limit of the first preset temperature range, the electronic control unit 400 can preferentially increase the opening of the intake bypass valve 130 to reduce the compression work of the supercharger 120 (thereby reducing the temperature rise), or cool it through the intercooler 150. In addition, the intake temperature can also be indirectly affected by adjusting the exhaust bypass valve 220 to change the turbine speed.

[0060] The air intake path for this step is as follows: Figure 2 As shown, air flows sequentially through the first intake booster passage 122 (first-stage compression by the supercharger 120) and the second intake booster passage 141 (second-stage compression by the turbocharger 140) before entering the two-stroke engine 300; at the same time, some of the air after the first-stage compression flows back to the inlet of the first intake booster passage 122 through the intake bypass valve 130.

[0061] The exhaust gas path for this step is as follows: Figure 2 As shown, some of the exhaust gas drives the turbine through the exhaust gas drive channel 142, and some of the exhaust gas is directly discharged through the exhaust gas bypass valve 220.

[0062] The system enables the mechanical supercharger 120 and the turbocharger 140 to work together, balancing transient response speed and high pressure ratio requirements. Through dual-valve closed-loop regulation, the intake pressure and temperature are precisely controlled, effectively improving the stability of operation under varying conditions and preventing a decline in scavenging quality.

[0063] Step S300: When the two-stroke engine 300 is in high-speed operation, the intake bypass valve 130 is fully opened, and the opening of the exhaust bypass valve 220 is controlled in real time, so that air flows through the intake bypass valve 130 and the second intake boosting channel 141 in sequence and enters the two-stroke engine 300. At the same time, some exhaust gas is directly discharged through the exhaust bypass valve 220, so as to maintain the intake pressure and intake temperature at the intake port of the two-stroke engine 300 within the second preset pressure range and the second preset temperature range, respectively.

[0064] When the two-stroke engine speed 300 is higher than the second speed threshold and the load is higher than the second load threshold, it is determined to be in high-speed operating condition. The turbocharger 140 enters the high-efficiency operating range, which is sufficient to independently maintain the high-pressure intake demand. At this time, the electronic control unit 400 controls the intake bypass valve 130 to be fully open and controls the opening degree of the exhaust bypass valve 220 in real time.

[0065] The air intake path for this step is as follows: Figure 3 As shown, outside air enters the second intake boost channel 141 (compressed by turbocharger 140) directly through the intake bypass valve 130, while the supercharger 120 runs idle, and the first intake boost channel 122 no longer effectively compresses the intake air.

[0066] The exhaust gas path for this step is as follows: Figure 3 As shown, the electronic control unit 400 adjusts the opening of the exhaust bypass valve 220 in real time according to the P2 and T2 feedback from the second pressure and temperature sensor 170, so that some exhaust gas is directly discharged through the exhaust bypass valve 220, and controls the exhaust gas flow rate entering the exhaust gas drive channel 142, thereby precisely adjusting the output power of the turbocharger 140.

[0067] The control objective is to maintain the intake pressure P2 and intake temperature T2 at the intake port of the two-stroke engine 300 within the second preset pressure range and the second preset temperature range, respectively.

[0068] The bypass supercharger 120 significantly reduces power consumption and mechanical losses under high-speed conditions. At the same time, by adjusting the exhaust bypass valve 220 in real time, the boost pressure and intake temperature are precisely controlled, avoiding over-boosting and excessive exhaust back pressure, so that the two-stroke engine 300 can maintain efficient and stable operation under high-speed conditions.

[0069] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0070] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A hybrid intake and supercharging system for a two-stroke engine, characterized in that, include: An intake piping assembly includes an intake pipe, a supercharger, an intake bypass valve, and a turbocharger. The outlet of the intake pipe is connected to the intake port of the two-stroke engine. The supercharger has a drive wheel system and a first intake boosting channel. The drive wheel system is used to drive the crankshaft of the two-stroke engine. The first intake boosting channel is used to boost the intake air under the drive of the crankshaft. The turbocharger has a second intake boosting channel and an exhaust gas drive channel. The exhaust gas drive channel is used to allow exhaust gas to enter and drive the turbine to rotate. The second intake boosting channel is used to boost the intake air under the drive of the turbine. The first and second intake boosting channels are connected in series in the intake pipe along the intake direction. The intake bypass valve is connected in parallel with the first intake boosting channel, and the intake bypass valve is configured to adjust its opening degree according to the operating conditions of the two-stroke engine. An exhaust piping assembly includes an exhaust pipe and an exhaust bypass valve; the inlet of the exhaust pipe is connected to the exhaust port of the two-stroke engine, and the exhaust gas drive passage is connected in series in the exhaust pipe; the exhaust gas bypass valve is connected in parallel with the exhaust gas drive passage, and the exhaust gas bypass valve is configured to adjust its opening degree according to the operating conditions of the two-stroke engine.

2. The hybrid intake turbocharger system according to claim 1, characterized in that: Both the intake bypass valve and the exhaust bypass valve are electrically controlled valves and are electrically connected to the electronic control unit in the two-stroke engine.

3. The hybrid intake turbocharger system according to claim 2, characterized in that: The electronic control unit is configured as follows: When the two-stroke engine is in the starting condition or low-speed condition, the intake bypass valve is controlled to close and the exhaust bypass valve is controlled to open fully. When the two-stroke engine is in a medium-speed or transient variable operating condition, the opening of the intake bypass valve and the exhaust bypass valve are controlled in real time to keep the intake pressure and intake temperature at the intake port of the two-stroke engine within a first preset pressure range and a first preset temperature range, respectively. When the two-stroke engine is operating at high speed, the intake bypass valve is fully opened, and the opening of the exhaust bypass valve is controlled in real time, so that the intake pressure and intake temperature at the intake port of the two-stroke engine are maintained within the second preset pressure range and the second preset temperature range, respectively.

4. The hybrid intake turbocharger system according to claim 3, characterized in that: The intake piping assembly also includes an intercooler, which is located between the outlet of the second intake boosting channel and the intake port of the two-stroke engine, and is used to cool the boosted intake air.

5. The hybrid intake turbocharger system according to claim 4, characterized in that: The intake manifold assembly also includes a first pressure-temperature sensor and a second pressure-temperature sensor. The first pressure-temperature sensor is used to detect the intake pressure and intake temperature at the outlet of the second intake boost channel, and the second pressure-temperature sensor is used to detect the intake pressure and intake temperature at the intake port of the two-stroke engine.

6. The hybrid intake turbocharger system according to claim 5, characterized in that: The first pressure and temperature sensor and the second pressure and temperature sensor are respectively electrically connected to the electronic control unit.

7. The hybrid intake turbocharger system according to claim 6, characterized in that: The electronic control unit is also configured to control the opening degree of the intake bypass valve and the exhaust bypass valve based on the real-time intake pressure and real-time intake temperature at the inlet of the second intake boost channel and the real-time intake temperature and real-time intake temperature at the intake port of the two-stroke engine.

8. The hybrid intake turbocharger system according to any one of claims 1 to 7, characterized in that: The supercharger is provided in two parts, and the first intake boosting channels of the two superchargers are connected in parallel in the intake pipe.

9. The hybrid intake turbocharger system according to claim 8, characterized in that: The two-stroke engine is a horizontally opposed type, and the two superchargers are arranged symmetrically with respect to the axis of the two-stroke engine.

10. A control method for a hybrid intake turbocharger system, characterized in that: The control method, applicable to any one of claims 1 to 9, comprises the following steps: When the two-stroke engine is in the starting condition or low-speed condition, the intake bypass valve is controlled to close and the exhaust bypass valve is controlled to open fully, so that air flows through the first intake boosting channel and the second intake boosting channel in sequence before entering the two-stroke engine. When the two-stroke engine is in a medium-speed or transient variable operating condition, the opening of the intake bypass valve and the exhaust bypass valve are controlled in real time to allow air to flow sequentially through the first intake boosting channel and the second intake boosting channel before entering the two-stroke engine. At the same time, a portion of the air compressed through the first intake boosting channel is returned to the inlet of the first intake boosting channel through the intake bypass valve, and a portion of the exhaust gas is directly discharged through the exhaust bypass valve, so as to maintain the intake pressure and intake temperature at the intake port of the two-stroke engine within a first preset pressure range and a first preset temperature range, respectively. When the two-stroke engine is operating at high speed, the intake bypass valve is fully opened, and the opening of the exhaust bypass valve is controlled in real time. This allows air to flow sequentially through the intake bypass valve and the second intake boosting channel before entering the two-stroke engine. At the same time, some exhaust gas is directly discharged through the exhaust bypass valve, thereby maintaining the intake pressure and intake temperature at the intake port of the two-stroke engine within the second preset pressure range and the second preset temperature range, respectively.

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