Engine air management system, control method and vehicle

Abstract

The invention provides an engine air management system, a control method and a vehicle, the engine air management system comprises: an engine having a first cylinder group and a second cylinder group, the first cylinder group comprising a plurality of first cylinders, and the second cylinder group comprising a plurality of second cylinders; the asymmetric supercharger comprises a first flow channel and a second flow channel, the sectional area of the first flow channel is smaller than that of the second flow channel, the asymmetric supercharger comprises a turbine flow channel, and exhaust channels of the first air cylinders and exhaust channels of the second air cylinders communicate with the turbine flow channel. The exhaust passage of each first cylinder is communicated with the inlet end of the first flow passage, the exhaust passage of each second cylinder is communicated with the inlet end of the second flow passage, and the inlet end of the first flow passage and the inlet end of the second flow passage are communicated with the exhaust manifold; and the variable valve timing mechanism is connected with each intake valve of the engine. The problem that the consistency of all cylinders becomes poor due to the fact that an asymmetric supercharger is used in an engine is solved.

Description

Technical Field

[0001] This invention relates to the field of engine air management system design technology, and more specifically, to an engine air management system, control method, and vehicle. Background Technology

[0002] The traditional internal combustion engine market is currently highly competitive, and emission regulations are becoming increasingly stringent, leading to ever-increasing demands for low emissions and high fuel economy in engines. Miller cycle and high EGR technologies are important technologies for balancing engine emissions and fuel economy. However, the EGR capability of an engine decreases as Miller intensity increases, making it difficult to provide EGR at high Miller intensities.

[0003] One-way valves, EGR pumps, and asymmetric turbochargers are all important technical solutions for improving engine EGR rates. Among them, the one-way valve solution has limited effect on improving EGR rate and is difficult to meet the requirements of high EGR rates. The EGR pump solution can precisely control and meet various EGR rate requirements, but a large EGR rate will lead to excessive power consumption and size of the EGR pump, making its placement difficult, and will also cause a significant temperature rise in the EGR gas. The asymmetric turbocharger solution can solve the above defects, but its asymmetric flow channel structure will lead to poor consistency among the cylinders of the engine.

[0004] There is currently no effective solution to the aforementioned problems in the existing technology. Summary of the Invention

[0005] The main objective of this invention is to provide an engine air management system, control method, and vehicle to solve the problem of poor cylinder consistency caused by the use of asymmetric turbochargers in existing engines.

[0006] To achieve the above objectives, according to one aspect of the present invention, an engine air management system is provided, comprising: an engine having a first cylinder bank and a second cylinder bank, the first cylinder bank including a plurality of first cylinders, and the second cylinder bank including a plurality of second cylinders; an asymmetric turbocharger including a first flow channel and a second flow channel, the cross-sectional area of ​​the first flow channel being smaller than the cross-sectional area of ​​the second flow channel, the asymmetric turbocharger including a turbine flow channel, and exhaust ports of each first cylinder and each second cylinder communicating with the turbine flow channel. The exhaust passage of each cylinder is connected to the inlet end of the first flow passage, and the exhaust passage of each second cylinder is connected to the inlet end of the second flow passage. The inlet ends of the first flow passage and the inlet ends of the second flow passage are both connected to the exhaust manifold. The EGR line is connected to the exhaust passage of each first cylinder. The variable valve timing mechanism is connected to each intake valve of the engine. The variable valve timing mechanism is used to adjust the Miller degree of the intake valve of each first cylinder and the variable valve timing mechanism is used to adjust the Miller degree of the intake valve of each second cylinder.

[0007] Furthermore, the Miller degree of the intake valve of each first cylinder is set in the same way, and the Miller degree of the intake valve of each second cylinder is set in the same way.

[0008] Furthermore, the engine air management system has an inter-cylinder consistency compensation mode. When the engine air management system is in the inter-cylinder consistency compensation mode, the Miller degree of the intake valve of the first cylinder is less than the Miller degree of the intake valve of the second cylinder.

[0009] Furthermore, the engine air management system has an economy mode. When the engine air management system is in economy mode, the Miller degree of the intake valve of the first cylinder is equal to the Miller degree of the intake valve of the second cylinder, and the Miller degree of the intake valve of the first cylinder is the maximum value within the Miller degree adjustment stroke of the variable valve timing mechanism.

[0010] Furthermore, the engine air management system has a power mode. When the engine air management system is in power mode, the Miller degree of the intake valve of the first cylinder is equal to the Miller degree of the intake valve of the second cylinder, and the Miller degree of the intake valve of the first cylinder is the minimum value within the Miller degree adjustment stroke of the variable valve timing mechanism.

[0011] Furthermore, a check valve is installed on the EGR pipeline.

[0012] Furthermore, an EGR valve is installed on the EGR pipeline.

[0013] Furthermore, a first vent valve is provided on the first flow channel, and a second vent valve is provided on the second flow channel.

[0014] To achieve the above objectives, according to one aspect of the present invention, a control method for an engine air management system is provided. The control method is used to control the engine air management system described above. The control method includes: acquiring engine operating parameters, the operating parameters including at least one of the following: load rate and engine speed; generating a target control instruction set based on the operating parameters, the target control instruction set being used to adjust the operating parameters of the engine air management system, the operating parameters including at least one of the following: the opening value of the EGR valve, the opening value of the first bleed valve, the opening value of the second bleed valve, and the operating mode of the variable valve timing mechanism.

[0015] Furthermore, the generation of the target control instruction set based on the operating condition parameters includes: in response to the speed being less than a first speed value and the load rate being greater than a first load value, generating a first target control instruction in the target control instruction set, wherein the first target control instruction is used to control the opening value of the EGR valve to the maximum value, control the opening value of the first bleed valve to the minimum value, and control the variable valve timing mechanism to be in the cylinder consistency compensation mode.

[0016] Furthermore, the generation of the target control instruction set based on the operating condition parameters includes: in response to the speed being greater than the second speed value and the load rate being greater than the first load value, generating a second target control instruction in the target control instruction set, the second target control instruction being used to control the opening value of the EGR valve to the maximum value, the second target control instruction being used to adjust the opening value of the first bleed valve in a closed loop based on the EGR achievement rate, and being used to control the variable valve timing mechanism to be in the inter-cylinder consistency compensation mode, the second speed value being greater than the first speed value.

[0017] Furthermore, the generation of the target control instruction set based on the operating condition parameters includes: in response to the load rate being less than the first load value and greater than the second load value, generating a third target control instruction in the target control instruction set; the third target control instruction is used to control the opening value of the first vent valve to the maximum value; the third target control instruction is used to adjust the opening value of the EGR valve in a closed loop based on the EGR achievement rate; and it is used to control the variable valve timing mechanism to be in the economy mode.

[0018] Furthermore, the generation of the target control instruction set based on the operating condition parameters includes: in response to the load rate being less than the second load value, generating a fourth target control instruction in the target control instruction set; the fourth target control instruction is used to control the opening value of the first bleed valve and the opening value of the second bleed valve to be at their maximum values; the fourth target control instruction is used to adjust the opening value of the EGR valve in a closed loop based on the EGR achievement rate; and to control the variable valve timing mechanism to be in the inter-cylinder consistency compensation mode.

[0019] Furthermore, the operating parameters include acceleration, and the target control instruction set generated based on the operating parameters includes: in response to the acceleration being greater than a preset acceleration value, generating a fifth target control instruction in the target control instruction set, the fifth target control instruction being used to control the opening value of the first vent valve, the opening value of the EGR valve, and the opening value of the second vent valve to be the minimum value.

[0020] According to another aspect of the present invention, a vehicle is provided, including an engine air management system, wherein the engine air management system is the engine air management system described above.

[0021] By applying the technical solution of this invention, a higher EGR rate is achieved by setting up a first cylinder bank and a second cylinder bank, and using an asymmetric turbocharger for corresponding boosting. A variable valve timing mechanism is used to adjust the Miller degree of the intake valves of the first and second cylinders, enabling the timely construction of an asymmetric Miller cycle. This balances the charging and pressure between the two cylinder banks, improving the consistency of each cylinder. This application, by constructing an asymmetric Miller cycle corresponding to the cylinders on both sides of the asymmetric turbocharger, can adjust the intake valve closing timing, thereby balancing the charging efficiency of each cylinder and solving the problem of poor cylinder consistency caused by using asymmetric turbochargers in existing engines. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 A schematic diagram of an embodiment of the engine air management system according to the present invention is shown;

[0024] Figure 2 A schematic diagram of the control curves of the first vent valve (small flow channel vent valve) under different operating conditions according to the present invention is shown;

[0025] Figure 3 A schematic diagram of the control curves of the second vent valve (small flow channel vent valve) under different operating conditions according to the present invention is shown;

[0026] Figure 4 A schematic diagram of the control curves for asymmetric Miller under different operating conditions according to the present invention is shown.

[0027] The above figures include the following reference numerals:

[0028] 1. Engine;

[0029] 21. First cylinder; 22. Second cylinder;

[0030] 4. Asymmetric turbocharger; 41. First flow channel; 42. Second flow channel;

[0031] 5. EGR piping;

[0032] 6. Check valve;

[0033] 7. EGR valve;

[0034] 8. First vent valve;

[0035] 9. Second vent valve. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0039] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0040] Combination Figures 1 to 4 As shown in the specific embodiment of this application, an engine air management system is provided, including: an engine 1, an asymmetric turbocharger 4, a variable valve timing mechanism, and an EGR pipeline 5. The engine 1 has a first cylinder bank and a second cylinder bank. The first cylinder bank includes a plurality of first cylinders 21, and the second cylinder bank includes a plurality of second cylinders 22. The asymmetric turbocharger 4 includes a first flow channel 41 and a second flow channel 42. The cross-sectional area of ​​the first flow channel 41 is smaller than the cross-sectional area of ​​the second flow channel 42. The asymmetric turbocharger 4 includes a turbine flow channel. The exhaust ports of each first cylinder 21 and each second cylinder 22 are connected to the turbine flow channel. The exhaust port of each first cylinder 21 is connected to the inlet end of the first flow channel 41. All are connected, and the exhaust passage of each second cylinder 22 is connected to the inlet end of the second flow passage 42. The inlet end of the first flow passage 41 and the inlet end of the second flow passage 42 are connected to the exhaust manifold. The inlet end of the EGR pipe 5 is connected to the exhaust passage of each first cylinder 21. The variable valve timing mechanism is connected to each intake valve of the engine 1. The variable valve timing mechanism is used to adjust the Miller degree of the intake valve of each first cylinder 21, and the variable valve timing mechanism is used to adjust the Miller degree of the intake valve of each second cylinder 22.

[0041] Specifically, the asymmetric turbocharger 4 includes a first flow channel 41, a second flow channel 42, and an exhaust flow channel. The asymmetric turbocharger 4 has two inlets and one outlet. The two inlets are connected to the first flow channel 41 and the second flow channel 42 respectively. The airflow converges in the turbine flow channel, and after the airflow performs work through the turbine, it flows into the exhaust manifold through the exhaust flow channel. By applying the technical solution of this invention, by setting up a first cylinder bank and a second cylinder bank, and using the asymmetric turbocharger 4 for corresponding boosting, a higher EGR rate is achieved. Furthermore, a variable valve timing mechanism is used to adjust the Miller degree of the intake valve of the first cylinder 21 and the intake valve of the second cylinder 22, enabling them to construct an asymmetric Miller condition in a timely manner. This balances the charging and pressure between the two cylinder banks, achieving the technical effect of improved cylinder consistency. This application solves the problem of poor cylinder consistency caused by the use of asymmetric turbochargers in existing engines.

[0042] By applying the technical solution of this invention, by constructing an asymmetrical Miller cycle corresponding to the two cylinders of the asymmetrical turbocharger 4, the timing of the intake valve closing of the cylinder can be adjusted, thereby balancing the charging efficiency of each cylinder and improving consistency.

[0043] An asymmetric turbocharger typically refers to a design within a twin-scroll turbocharger where the exhaust gas inlet of the turbine section is designed as two channels of different sizes or shapes, each connecting to the engine's exhaust manifold. The primary purpose of this design is to optimize engine performance and efficiency under different operating conditions, particularly improving the efficiency of the exhaust gas recirculation (EGR) system, as well as enhancing engine emissions and fuel economy.

[0044] It's important to understand from the manual that the Miller cycle is a working cycle where, with a fixed engine expansion stroke, the engine's compression stroke is shorter than its expansion stroke by adjusting the intake valve closing angle. Early or late intake valve closing are both ways to achieve the Miller cycle. Miller degree (°CA) = actual intake valve closing angle (IVC) minus the traditional Otto cycle IVC reference angle (unit: crankshaft angle, °CA). For example, if a certain engine's traditional IVC is 40° after bottom dead center (reference angle), and the Miller cycle adjusts it to 80° after bottom dead center, then the Miller degree under this condition is the difference of 40°. Miller degree can be understood as the amount of valve timing adjustment by the Miller cycle.

[0045] The working principle of an asymmetric turbocharger is as follows: An asymmetric turbocharger has two independent exhaust gas inlets on one side of the turbine. One flow path (usually called the smaller flow path) is designed to be smaller or longer than the other (the larger flow path), allowing for separate control of the exhaust gas flow from different cylinders. The engine cylinders are grouped into one of the two flow paths. Typically, under low-speed, high-load conditions, cylinders with higher exhaust gas pressure are assigned to the smaller flow path, while under high-speed, low-load conditions, cylinders with lower exhaust gas pressure are assigned to the larger flow path.

[0046] Small flow channels, due to their narrowness or length, generate higher exhaust back pressure, which is beneficial for improving the EGR rate. Large flow channels, designed to be wider or shorter, allow for smoother exhaust flow, reducing back pressure and improving boosting efficiency. By adjusting the opening of the bleed valves (small flow channel bleed valve and large flow channel bleed valve, the small flow channel bleed valve being the first bleed valve 8 and the large flow channel bleed valve being the second bleed valve 9), the pressure inside the flow channels can be controlled, thereby adjusting the EGR rate and boosting effect. However, due to their physical structure, this can lead to different back pressures on the two cylinders, causing cylinder inconsistency issues.

[0047] Current solutions for improving cylinder consistency primarily focus on the intake manifold. One approach is independent intake for each cylinder; another is an intake throttling scheme, which uses baffles or throttle valves to reduce the intake efficiency of cylinders with high charging efficiency. In one optional embodiment, to improve intake airflow, different valve profiles are used between the two valves of the same cylinder. This approach aims to improve the in-cylinder airflow organization and mixing. The different valve profiles between cylinders provided in the above embodiment are superior.

[0048] The main reason for the inconsistent performance of cylinders in the asymmetric turbocharger design is the difference in the inlet pressure between the large and small flow channels, which leads to different exhaust back pressure differences for the corresponding cylinders of the large and small flow channels. As a result, there are significant differences in the charging efficiency of each cylinder, and therefore the intake volume and work capacity of each cylinder are different.

[0049] By adjusting the intake valve Miller degree of the first and second cylinders using a variable valve timing mechanism, an asymmetric Miller scheme is essentially constructed. This scheme utilizes the influence of Miller degree on the charging efficiency of each cylinder to balance the charging efficiency of each cylinder. The cylinder corresponding to the larger flow channel (second flow channel 42) has low exhaust pressure and high charging efficiency, so a slightly larger Miller degree angle is used to reduce its charging efficiency. Conversely, the cylinder corresponding to the smaller flow channel (first flow channel 41) has high exhaust pressure and low charging efficiency, so a slightly smaller Miller degree angle is used to increase its charging efficiency, thereby achieving the goal of consistent charging efficiency between the two cylinders.

[0050] In an optional embodiment, those skilled in the art can appropriately select the variable valve timing mechanism. The variable valve timing mechanism is used to adjust the Miller degree of the intake valve of each first cylinder 21, and the variable valve timing mechanism is used to adjust the Miller degree of the intake valve of each second cylinder 22, specifically including the following schemes:

[0051] The first implementation method is a fixed camshaft scheme. Taking a 6-cylinder engine (numbered 1, 2, 3, 4, 5, and 6) as an example, this scheme can use different valve profile designs for cylinders 1, 2, and 3 compared to cylinders 4, 5, and 6, achieving different Miller indices for cylinders 1, 2, and 3, thus improving engine consistency across most operating conditions. In this case, both the first and second cylinder banks use a fixed Miller indices, but the Miller indices are different, for example, 10° and 30° respectively.

[0052] The second approach involves a two-stage camshaft drive system, with cylinders 1, 2, and 3 forming one stage and cylinders 4, 5, and 6 forming another. One stage uses a fixed camshaft drive structure, while the other uses a variable drive structure. Depending on the engine's operating conditions, the Miller index of the corresponding three cylinders is adjusted using the variable drive structure to achieve balance on both sides. In this case, the Miller index of one cylinder bank is fixed, while the Miller index of the other cylinder bank is adjustable, allowing the difference in Miller index between the two to be variable.

[0053] The third implementation method is a six-cylinder fully variable drive scheme. This method is flexible and allows for independent adjustment of the Miller index of each cylinder according to the engine's operating conditions, achieving a consistent balance across all six cylinders. In this case, the Miller index of both cylinder banks can be adjusted. This scheme has a higher cost, but skilled technicians can choose a suitable scheme or make reasonable improvements based on cost accounting, space layout, etc., as long as the Miller index difference between the two cylinder banks is established to balance the charging efficiency.

[0054] like Figure 1 The diagram shown is an architecture diagram of the air management system. Figure 1 The diagram shows the connection position between the intake manifold and the pressure regulating chamber, which can be either the central intake shown or the left and right side intakes. The large and small flow channels of the asymmetric turbocharger can be interchanged; the EGR intake position corresponding to the small flow channel and the asymmetric Miller scheme require corresponding adjustments. There are no variations in other structural connections. The asymmetric turbocharger is the primary component, providing a high EGR rate, and combined with the asymmetric Miller scheme to improve consistency across cylinders; the EGR pump replaces the EGR valve for precise EGR rate control and provides appropriate EGR rate boosts; the one-way valve scheme assists in a slight increase in EGR rate.

[0055] In an optional embodiment, the Miller degree adjustment stroke of the variable valve timing mechanism is 0 to 40 CA, wherein a larger Miller degree (greater than 30 CA) is preferred, and a smaller Miller degree (less than 30 CA) is preferred. Engineers can perform calibration in different engines.

[0056] Furthermore, the Miller degree of the intake valve of each first cylinder 21 is set in the same way, and the Miller degree of the intake valve of each second cylinder 22 is set in the same way.

[0057] Furthermore, the engine air management system has an inter-cylinder consistency compensation mode. When the engine air management system is in the inter-cylinder consistency compensation mode, the Miller degree of the intake valve of the first cylinder 21 is less than the Miller degree of the intake valve of the second cylinder 22.

[0058] Adjusting the Miller index can affect the cylinder's charging efficiency, thus impacting engine performance and efficiency. In cylinder consistency compensation mode, the intake valve Miller indexes of cylinder 21 and cylinder 22 are set to different values, specifically, the intake valve Miller index of cylinder 21 is lower than that of cylinder 22. The ingenuity of this setting lies in the fact that, through differentiated Miller index adjustments, the difference in exhaust back pressure between cylinders caused by different flow paths in the asymmetric turbocharger can be balanced, thereby improving the charging efficiency of each cylinder and ensuring that the operating conditions of all cylinders are as consistent as possible under different engine operating conditions, thereby improving the overall smoothness and efficiency of engine operation.

[0059] More specifically, the Miller degree adjustment of the first cylinder 21 and the second cylinder 22 is achieved through a variable valve timing (VVA) mechanism. This mechanism allows for independent control of the intake valve timing of each cylinder, enabling the intake valve Miller degree of both cylinders to be adjusted according to the characteristics of the turbocharger flow passages to which the first cylinder 21 and the second cylinder 22 are connected, thereby achieving the effect of compensating for inter-cylinder consistency. Under low-speed, high-load conditions, the charging efficiency of the small flow passage connected to the second cylinder 22 may be relatively low due to the higher exhaust back pressure. Therefore, setting the intake valve Miller degree of the second cylinder 22 to a smaller value helps to improve the charging efficiency, thereby increasing the engine's EGR rate and improving torque output. Conversely, the large flow channel connected to the first cylinder 21 may have a higher charging efficiency due to the lower exhaust back pressure. Therefore, setting the intake valve Miller degree of the first cylinder 21 to a larger value can appropriately reduce the charging efficiency to ensure that the charging conditions are closer to those of the second cylinder 22, thereby improving the inter-cylinder consistency between the first cylinder 21 and the second cylinder 22.

[0060] The cylinder consistency compensation mode in this embodiment effectively compensates for the differences in cylinder operating conditions caused by the asymmetric turbocharger by finely adjusting the Miller degree of each cylinder, ensuring that all cylinders have similar charging efficiency under specific operating conditions. This mode can significantly improve the engine's operating quality under complex operating conditions, reduce engine vibration and noise, and optimize combustion efficiency, thereby achieving better cylinder consistency without affecting the overall engine performance, ensuring smooth engine operation and improving driving comfort. In practical applications, through the control strategy of this embodiment, the engine can achieve a balance of charging efficiency under low-speed, high-load conditions by finely adjusting the intake valve Miller degree of the first cylinder 21 and the second cylinder 22, effectively overcoming the potential problems caused by the asymmetric turbocharger and improving the overall operating reliability and efficiency of the engine.

[0061] Furthermore, the engine air management system has an economy mode. When the engine air management system is in economy mode, the Miller degree of the intake valve of the first cylinder 21 is equal to the Miller degree of the intake valve of the second cylinder 22, and the Miller degree of the intake valve of the first cylinder 21 is the maximum value within the Miller degree adjustment stroke of the variable valve timing mechanism.

[0062] In this embodiment, the economy mode is designed as an operating state in which the engine air management system aims to improve fuel efficiency and operating economy by optimizing the cylinder charging and combustion processes. A key feature of this mode is the intake valve Miller degree setting for the first cylinder 21 and the second cylinder 22, ensuring that they are equal, and that this Miller degree is set to the maximum value within the adjustment stroke of the variable valve timing (VVA) mechanism.

[0063] Miller degree, as a manifestation of the Miller cycle, refers to the difference (°CA) between the actual angle at which the intake valve closes prematurely before the start of the compression stroke. In Eco mode, the intake valve Miller degrees of cylinders 21 and 22 are set to be equal and maximized. The originality of this feature lies in utilizing the principle of the Miller cycle to improve the engine's fuel economy. At the same time, by maintaining consistent Miller degrees, it ensures that all cylinders have similar charging efficiency, thereby achieving uniform operation among cylinders in Eco mode and avoiding efficiency losses and emission problems caused by differences in operating conditions between cylinders.

[0064] Variable Valve Timing (VVA) is a component in the engine's air management system used to control the opening and closing sequence of the intake and exhaust valves. It allows the engine to dynamically adjust valve timing under different operating conditions to improve efficiency and performance. In Eco mode, the Miller index adjustment stroke of the VVA is fully utilized and set to its maximum value to maximize cylinder charging efficiency, thereby minimizing fuel consumption and improving thermal efficiency while ensuring engine output torque.

[0065] The intake valve Miller degrees of cylinders 21 and 22 are set to be equal and maximized. This setting ensures that the charging process of all cylinders is optimized in Eco mode. In practical applications, when the engine is running in Eco mode, the VVA mechanism adjusts the intake valve Miller degrees of cylinders 21 and 22 to their maximum values. This not only improves the cylinder charging efficiency, reduces the compression ratio, and reduces pumping losses, but also avoids unnecessary combustion fluctuations by ensuring consistency between cylinders, resulting in a more stable combustion process and higher thermal efficiency. Furthermore, this setting helps maintain a higher EGR rate under low-load conditions, further reducing nitrogen oxide (NOx) and hydrocarbon (HC) emissions, meeting stringent emission regulations, and improving fuel economy and driving experience for the driver.

[0066] The economic mode of this application embodiment ensures consistency in charging efficiency and maximizes the optimization of the charging process between cylinders by precisely controlling the Miller indices of the first cylinder 21 and the second cylinder 22. This significantly improves fuel efficiency and thermal efficiency without sacrificing engine performance, while simultaneously meeting stringent emission regulations, providing drivers with a dual improvement in both economy and environmental performance. In economic mode, the Miller indices of the first cylinder 21 and the second cylinder 22 are set to their maximum values ​​within the adjustment stroke of the variable valve timing mechanism. This strategy effectively balances the operating states of all cylinders, reduces pumping losses, and optimizes the combustion process, thereby achieving the goals of both economic and environmental performance in engine operation.

[0067] Furthermore, the engine air management system has a power mode. When the engine air management system is in the power mode, the Miller degree of the intake valve of the first cylinder 21 is equal to the Miller degree of the intake valve of the second cylinder 22, and the Miller degree of the intake valve of the first cylinder 21 is the minimum value within the Miller degree adjustment stroke of the variable valve timing mechanism.

[0068] In this embodiment, the power performance mode of the engine air management system is an operating state specifically designed to improve the engine's transient response speed and acceleration performance. The core feature of this mode lies in the setting of the intake valve Miller degree of the first cylinder 21 and the second cylinder 22. Specifically, the Miller degree of the two cylinders is set to be exactly equal, and the value of this Miller degree is equal to the minimum value within the Miller degree range that the variable valve timing mechanism can adjust.

[0069] Miller degree, in this context, refers to the deviation between the actual closing time of the intake valve and the theoretical closing time of the intake valve in the traditional Otto cycle, measured in crankshaft angles (°CA). In power mode, the intake valve Miller degree of cylinders 21 and 22 is set to its minimum value via a variable valve timing mechanism. This means the intake valve closing time is delayed, increasing the effective intake volume and compression ratio of the cylinders, thereby generating more power in a short time. The ingenuity of this setting lies in its ability to quickly respond to the driver's demand for acceleration performance without sacrificing the long-term operational stability of the engine.

[0070] The variable valve timing mechanism, a key component of the engine air management system, is responsible for dynamically adjusting the opening and closing sequence of the intake and exhaust valves. In power mode, this mechanism sets the Miller index of the intake valves of the first cylinder 21 and the second cylinder 22 to the minimum value. This action allows the entire system to quickly adapt to the driver's demand for instantaneous power, especially when starting the vehicle or overtaking, it can immediately provide the required additional torque to enhance the vehicle's acceleration performance.

[0071] In the configuration of this application embodiment, the power mode effectively enhances the engine's transient response and acceleration performance by setting the intake valve Miller degree of the first cylinder 21 and the second cylinder 22 to the minimum value within the adjustment stroke of the variable valve timing mechanism. This operation increases the effective intake volume of the cylinders and improves the compression ratio, enabling the engine to release greater explosive power in a short time, satisfying the driver's urgent demand for acceleration performance. At the same time, keeping the Miller degree of the two cylinders equal ensures that while increasing power output, the engine's operating state remains consistent, avoiding performance imbalances caused by differences in cylinder operating conditions, further improving the driving experience and vehicle handling safety. In power mode, by precisely controlling the intake valve Miller degree of the first cylinder 21 and the second cylinder 22 to the minimum value, this application embodiment effectively balances high power output with the consistency of engine cylinder operation, achieving a good combination of instantaneous strong power and system stability, significantly improving vehicle acceleration performance and user driving experience.

[0072] Furthermore, a check valve 6 is installed on the EGR line 5.

[0073] Furthermore, an EGR valve 7 is installed on the EGR pipeline 5.

[0074] Furthermore, a first vent valve 8 is provided on the first flow channel 41, and a second vent valve 9 is provided on the second flow channel 42.

[0075] In one alternative embodiment, the engine air management system includes an intake manifold, a turbocharger, an intake intercooler, a throttle valve, a mixer, intake and exhaust valves, an exhaust manifold, an EGR line, a one-way valve, and an EGR valve / EGR pump.

[0076] The intake and exhaust valves are variable valve timing (VVA) mechanisms, with each cylinder's VVA mechanism independently controlled, allowing for flexible adjustment of the intake and exhaust valve phase and lift. The turbocharger is an asymmetric dual-flow turbocharger, with the smaller flow path connecting to the exhaust pipe and corresponding to the EGR intake line to provide EGR for the intake air. The asymmetric turbocharger features a dual wastegate structure, with independent control of the large and small flow paths for wastegate. By using a one-way valve + asymmetric turbocharger + EGR valve scheme, sufficient EGR capacity is achieved at low speeds and high loads, eliminating the need for a throttle valve and a high-recovery venturi structure on the intake side, thus reducing intake losses.

[0077] Optionally, a high-efficiency large turbine casing solution can be used on the exhaust side to effectively reduce turbine inlet pressure.

[0078] Optionally, the EGR valve can be replaced by an EGR pump solution. The three measures of one-way valve, asymmetric turbocharger and EGR pump solution complement each other. The use of asymmetric turbocharger can reduce the pressure ratio requirement of EGR pump, thereby reducing the size and power consumption of EGR pump and avoiding significant temperature rise of EGR gas. The application of EGR pump can reduce the requirement for turbocharger asymmetry and improve the difference between cylinders and the efficiency loss of turbine end.

[0079] To achieve the above objectives, according to one aspect of the present invention, a control method for an engine air management system is provided. The control method is used to control the aforementioned engine air management system, and includes:

[0080] Obtain the engine's operating parameters, which include at least one of the following: load rate and speed;

[0081] The purpose of load rate and speed is to determine the engine's load conditions.

[0082] A target control instruction set is generated based on the operating parameters. The target control instruction set is used to adjust the operating parameters of the engine air management system. The operating parameters include at least one of the following: the opening value of EGR valve 7, the opening value of the first bleed valve 8, the opening value of the second bleed valve 9, and the operating mode of the variable valve timing mechanism.

[0083] Engine load conditions are primarily distinguished by engine speed and throttle signal. The ECU can determine the engine's load range using the engine speed sensor and throttle signal. Different engine speeds correspond to different throttle signal ranges. Engine operating conditions are described by engine speed and load rate, with the load rate expressed as the percentage of actual torque reaching the external characteristic torque. Low-speed, high-load conditions are defined as engine speeds below 1300 rpm and load rates above 70%; high-speed, high-load conditions are defined as engine speeds above 1400 rpm and load rates above 70%; medium-low load conditions are defined as all engine speeds with load rates between 30-70%; and low-load conditions are defined as all engine speeds with load rates below 30%.

[0084] Furthermore, the generation of the target control instruction set based on operating condition parameters includes:

[0085] In response to the speed being less than the first speed value and the load rate being greater than the first load value, a first target control instruction is generated in the target control instruction set. The first target control instruction is used to control the opening value of EGR valve 7 to the maximum value, control the opening value of the first bleed valve 8 to the minimum value, and control the variable valve timing mechanism to be in the cylinder consistency compensation mode.

[0086] The preferred initial engine speed is 1300 rpm. The initial load is 70% of the torque. At this point, the engine is operating under low-speed, high-load conditions. The intake pressure is higher than the turbine inlet pressure, making EGR difficult to achieve. Therefore, the small-flow wastegate valve of the asymmetric turbocharger closes, while the EGR valve fully opens to maximize EGR capacity. Simultaneously, the large-flow wastegate valve opening increases, controlling engine output torque. This achieves a high Miller cycle and high EGR rate while suppressing knock, resulting in optimal combustion phase and best fuel economy. The intake valve VVA mechanism uses a Miller degree >30 CA for the cylinders on the large-flow side and a Miller degree 10-20 CA lower for the cylinders on the small-flow side to balance the charge, internal EGR, and pressure of both cylinders. The large-flow side employs closed-loop control based on the engine's target torque.

[0087] In this embodiment, since the required EGR rate is achieved by using a small flow channel, the large and small flow channels have different back pressures, which will lead to a problem of poor consistency between cylinders corresponding to the two flow channels. At this time, by using a larger Miller degree for the cylinder on the side corresponding to the large flow channel and a Miller degree 10-20CA lower for the cylinder on the side corresponding to the small flow channel than the side corresponding to the large flow channel, the charge and pressure of the two cylinders can be balanced.

[0088] Furthermore, the generation of the target control instruction set based on operating condition parameters includes:

[0089] In response to the speed being greater than the second speed value and the load rate being greater than the first load value, a second target control instruction is generated in the target control instruction set. The second target control instruction is used to control the opening value of EGR valve 7 to the maximum value, the second target control instruction is used to adjust the opening value of the first bleed valve 8 in a closed loop based on the EGR achievement rate, and to control the variable valve timing mechanism to be in the inter-cylinder consistency compensation mode, where the second speed value is greater than the first speed value.

[0090] The preferred second engine speed is 1400 rpm, and the preferred first load is 70% of the torque. Under low-speed, high-load conditions, the engine intake pressure is higher than the turbine inlet pressure, making EGR difficult. At this point, the small-flow wastegate valve of the asymmetric turbocharger closes, while the EGR valve fully opens to achieve maximum EGR capability. Simultaneously, the large-flow wastegate valve opening increases, controlling the engine output torque. This achieves a high Miller cycle and high EGR rate while suppressing knock, resulting in optimal combustion phase and best fuel economy. The intake valve VVA mechanism uses a Miller degree >30°CA for the cylinders on the large-flow side and a Miller degree 10-20°CA lower for the cylinders on the small-flow side to balance the charge, internal EGR, and pressure of both cylinders. The large-flow wastegate valve uses closed-loop control based on the engine's target torque.

[0091] In this embodiment, since the required EGR rate is achieved by using a small flow channel, the large and small flow channels have different back pressures, which will lead to a problem of poor cylinder consistency between the corresponding cylinders of the two flow channels. At this time, by using a larger Miller degree for the cylinder on the side corresponding to the large flow channel and a Miller degree 10-20°CA lower for the cylinder on the side corresponding to the small flow channel than the large flow channel side, the charge and pressure of the two cylinders can be balanced.

[0092] Furthermore, the generation of the target control instruction set based on operating condition parameters includes:

[0093] In response to a load rate that is less than a first load value but greater than a second load value, a third target control command is generated in the target control command set. The third target control command is used to control the opening value of the first vent valve 8 to the maximum value, the third target control command is used to adjust the opening value of the EGR valve 7 in a closed loop based on the EGR achievement rate, and the third target control command is used to control the variable valve timing mechanism to be in the economy mode.

[0094] Under light to medium load conditions, when the engine's boost and EGR capabilities are sufficient, the small-channel wastegate of the asymmetric turbocharger is fully open, and the EGR rate is controlled by the EGR valve. The large-channel wastegate controls the output torque, maximizing the pressure balance between the large and small channels. In this configuration, the VVA mechanism employs the same high Miller degree scheme (Miller degree > 30°CA) on both sides of the large and small channels. Because the boost capability is sufficient, the small-channel valve does not need to hold air, and therefore can be fully open. Its EGR rate is controlled by the EGR valve, while the large-channel wastegate directly uses closed-loop control based on the engine's target torque.

[0095] In this case, a specific Miller cycle scheme will be adopted based on the target operating conditions. Since the large Miller cycle is characterized by high boost pressure demand and low fuel consumption, while the small Miller cycle is characterized by low boost pressure demand and superior acceleration, the combination of the two can resolve the conflict between low fuel consumption and acceleration. Under steady-state conditions, if fuel economy is prioritized, both cylinders can be switched to the large Miller cycle. For acceleration conditions, the small Miller cycle can be used to maximize power.

[0096] Furthermore, the generation of the target control instruction set based on the operating condition parameters includes: in response to the load rate being less than the second load value, generating a fourth target control instruction in the target control instruction set; the fourth target control instruction is used to control the opening value of the first bleed valve 8 and the opening value of the second bleed valve 9 to be at their maximum values; the fourth target control instruction is used to adjust the opening value of the EGR valve 7 in a closed loop based on the EGR achievement rate; and to control the variable valve timing mechanism to be in the inter-cylinder consistency compensation mode.

[0097] Under light load conditions, when the engine's boost and EGR capabilities are sufficient, the wastegate valves of both the large and small flow channels of the asymmetric turbocharger are fully open simultaneously. At this time, the EGR rate is controlled by the EGR valve, and the engine torque output is controlled by the throttle valve, maximizing the pressure balance between the large and small flow channels. The intake valve VVA mechanism uses a Miller degree greater than 30°CA for the cylinders on the large flow channel side and a lower Miller degree of 0-10CA for the cylinders on the small flow channel side, balancing the charge, internal EGR, and pressure of both cylinders. Because the system's boost capability is sufficient, both the large and small flow channels are open simultaneously. The large flow channel valve no longer controls the output torque; instead, the throttle valve controls the output torque. However, due to the physical structure of the large and small flow channels, a small Miller degree difference must still be maintained between the two cylinders.

[0098] Furthermore, the operating parameters include acceleration, and the target control instruction set generated based on the operating parameters includes: in response to the acceleration being greater than a preset acceleration value, generating a fifth target control instruction in the target control instruction set, the fifth target control instruction being used to control the opening value of the first vent valve 8, the opening value of the EGR valve 7, and the opening value of the second vent valve 9 to be the minimum value.

[0099] During engine acceleration, the wastegate valves in both the large and small flow channels of the asymmetric turbocharger are completely closed, and the EGR valve (EGR pump) is shut off, providing the engine with maximum boost capacity and zero EGR rate. The intake valve VVA mechanism uses the same Miller degree scheme (Miller degree less than 30°CA) on both sides of the large and small flow channels to ensure the fastest acceleration response.

[0100] The technical solution of this application solves the following technical problems by employing the following technical means: An asymmetric dual-flow turbocharger is used, in which the smaller flow channel is connected to the exhaust pipe to improve the EGR rate. A one-way valve and an EGR valve are combined; the one-way valve assists in a slight increase in the EGR rate, while the EGR valve precisely controls the EGR rate. Asymmetric Miller cycle control for each cylinder is introduced; by adjusting the Miller degree of different cylinders, the intake volume and internal EGR of each cylinder are balanced, improving cylinder consistency. This application solves the technical problem of how to improve the exhaust gas recirculation (EGR) rate of an engine under high Miller cycle conditions to meet stringent emission standards and improve fuel economy. Furthermore, this application solves the problem of cylinder consistency caused by the asymmetric turbocharger, ensuring balanced engine performance.

[0101] The technical effects achieved by adopting the technical solution of the embodiments of this application are as follows:

[0102] 1. Provides sufficient EGR capacity under low-speed, high-load conditions, while achieving a large Miller cycle, suppressing knocking, optimizing combustion phase, and enhancing fuel economy.

[0103] 2. Under high-speed and high-load conditions, maintain a stable EGR rate while controlling torque output and balancing the pressure in both flow channels to ensure engine performance and efficiency.

[0104] 3. Under medium and light load conditions, the EGR rate and torque are controlled by the large and small flow channels of the bleed valve and EGR valve. At the same time, a large Miller degree scheme is adopted to maintain the consistency of each cylinder of the engine and high economy.

[0105] 4. Under low load conditions, by adjusting Miller index and fully opening the bleed valve, the EGR rate is controlled and the cylinder charge volume is balanced to maintain engine stability.

[0106] 5. Under acceleration conditions, all EGR-related components are turned off, and the Mildred solution is adopted to maximize the engine's boost capacity and response speed.

[0107] According to another aspect of the present invention, a vehicle is provided, including an engine air management system, wherein the engine air management system is the engine air management system described above.

[0108] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects: by combining an asymmetric turbocharger, a one-way valve, an EGR valve, and an asymmetric Miller scheme, the maximum EGR rate is provided and controlled, while ensuring consistency across all cylinders of the engine. This scheme primarily uses an asymmetric turbocharger to provide a high EGR rate, combined with an asymmetric Miller scheme to improve cylinder consistency; the EGR valve provides precise EGR rate control; and the one-way valve scheme assists in a slight increase in the EGR rate. Overall, the system scheme achieves the maximum EGR rate provision effect.

[0109] This invention proposes an asymmetric Miller scheme for each cylinder, which effectively improves the consistency of each cylinder under the asymmetric turbocharger scheme.

[0110] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0111] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0112] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An engine air management system, characterized in that, include: An engine (1) has a first cylinder bank and a second cylinder bank, the first cylinder bank including a plurality of first cylinders (21) and the second cylinder bank including a plurality of second cylinders (22). An asymmetric turbocharger (4) includes a first flow channel (41) and a second flow channel (42). The cross-sectional area of ​​the first flow channel (41) is smaller than that of the second flow channel (42). The asymmetric turbocharger (4) includes a turbine flow channel. The exhaust passages of each first cylinder (21) and each second cylinder (22) are connected to the turbine flow channel. The exhaust passages of each first cylinder (21) are connected to the inlet end of the first flow channel (41). The exhaust passages of each second cylinder (22) are connected to the inlet end of the second flow channel (42). The inlet end of the first flow channel (41) and the inlet end of the second flow channel (42) are connected to the exhaust manifold. EGR line (5), the inlet end of which is connected to the exhaust passage of each of the first cylinders (21); A variable valve timing mechanism is connected to each intake valve of the engine (1). The variable valve timing mechanism is used to adjust the Miller degree of the intake valve of each first cylinder (21) and the variable valve timing mechanism is used to adjust the Miller degree of the intake valve of each second cylinder (22).

2. The engine air management system according to claim 1, characterized in that, The Miller degree of the intake valve of each of the first cylinders (21) is set to be the same, and the Miller degree of the intake valve of each of the second cylinders (22) is set to be the same.

3. The engine air management system according to claim 1 or 2, characterized in that, The engine air management system has an inter-cylinder consistency compensation mode. When the engine air management system is in the inter-cylinder consistency compensation mode, the Miller degree of the intake valve of the first cylinder (21) is less than the Miller degree of the intake valve of the second cylinder (22).

4. The engine air management system according to claim 1 or 2, characterized in that, The engine air management system has an economy mode. When the engine air management system is in the economy mode, the Miller degree of the intake valve of the first cylinder (21) is equal to the Miller degree of the intake valve of the second cylinder (22), and the Miller degree of the intake valve of the first cylinder (21) is the maximum value within the Miller degree adjustment stroke of the variable valve timing mechanism.

5. The engine air management system according to claim 1 or 2, characterized in that, The engine air management system has a power mode. When the engine air management system is in the power mode, the Miller degree of the intake valve of the first cylinder (21) is equal to the Miller degree of the intake valve of the second cylinder (22), and the Miller degree of the intake valve of the first cylinder (21) is the minimum value within the Miller degree adjustment stroke of the variable valve timing mechanism.

6. The engine air management system according to claim 1, characterized in that, A check valve (6) is installed on the EGR pipeline (5).

7. The engine air management system according to claim 1, characterized in that, An EGR valve (7) is installed on the EGR pipeline (5).

8. The engine air management system according to claim 1, characterized in that, A first vent valve (8) is provided on the first flow channel (41), and a second vent valve (9) is provided on the second flow channel (42).

9. A control method for an engine air management system, the control method being used to control the engine air management system according to any one of claims 1 to 8, characterized in that, The control method includes: Obtain the engine's operating parameters, which include at least one of the following: load rate, speed; A target control instruction set is generated based on the operating parameters. The target control instruction set is used to adjust the operating parameters of the engine air management system. The operating parameters include at least one of the following: the opening value of the EGR valve (7), the opening value of the first bleed valve (8), the opening value of the second bleed valve (9), and the operating mode of the variable valve timing mechanism.

10. The control method according to claim 9, characterized in that, Generating a target control instruction set based on the aforementioned operating parameters includes: In response to the speed being less than a first speed value and the load rate being greater than a first load value, a first target control instruction is generated in the target control instruction set. The first target control instruction is used to control the opening value of the EGR valve (7) to the maximum value, control the opening value of the first vent valve (8) to the minimum value, and control the variable valve timing mechanism to be in the cylinder consistency compensation mode.

11. The control method according to claim 10, characterized in that, Generating a target control instruction set based on the aforementioned operating parameters includes: In response to the speed being greater than the second speed value and the load rate being greater than the first load value, a second target control instruction is generated in the target control instruction set. The second target control instruction is used to control the opening value of the EGR valve (7) to the maximum value. The second target control instruction is used to adjust the opening value of the first bleed valve (8) based on the EGR achievement rate in a closed loop, and to control the variable valve timing mechanism to be in the inter-cylinder consistency compensation mode. The second speed value is greater than the first speed value.

12. The control method according to claim 10, characterized in that, Generating a target control instruction set based on the aforementioned operating parameters includes: In response to the load rate being less than the first load value and greater than the second load value, a third target control instruction is generated in the target control instruction set. The third target control instruction is used to control the opening value of the first vent valve (8) to the maximum value. The third target control instruction is used to adjust the opening value of the EGR valve (7) in a closed loop based on the EGR achievement rate, and to control the variable valve timing mechanism to be in the economy mode.

13. The control method according to claim 12, characterized in that, Generating a target control instruction set based on the aforementioned operating parameters includes: In response to the load rate being less than the second load value, a fourth target control instruction is generated in the target control instruction set. The fourth target control instruction is used to control the opening value of the first bleed valve (8) and the opening value of the second bleed valve (9) to be the maximum value. The fourth target control instruction is used to adjust the opening value of the EGR valve (7) in a closed loop based on the EGR achievement rate, and to control the variable valve timing mechanism to be in the cylinder consistency compensation mode.

14. The control method according to claim 9, characterized in that, The operating parameters include acceleration, and generating a target control command set based on the operating parameters includes: In response to the acceleration being greater than a preset acceleration value, a fifth target control instruction in the target control instruction set is generated. The fifth target control instruction is used to control the opening value of the first vent valve (8), the opening value of the EGR valve (7), and the opening value of the second vent valve (9) to be the minimum value.

15. A vehicle comprising an engine air management system, characterized in that, The engine air management system is the engine air management system according to any one of claims 1 to 8.

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