Method, device and storage medium for determining exhaust valve closing phase

Abstract

The application provides a method, device and storage medium for determining an exhaust valve closing phase, which is applied to the technical field of vehicle engines. The method comprises the following steps: obtaining a power demand and an economic demand of the engine; performing power simulation on the engine according to the power demand, to obtain a first feasible range of the exhaust valve closing phase of the engine; performing economic simulation on the engine according to the economic demand and the first feasible range, to obtain a candidate phase of the exhaust valve closing phase of the engine; and determining an optimal exhaust valve closing phase of the engine according to the candidate phase. The method can start from the power demand and the economic demand of the engine, and determine the optimal exhaust valve closing phase of the engine by performing power and economic simulation and analysis on the engine, so that the engine performance can meet the performance demand of the whole vehicle, and the fuel consumption is reduced to the lowest level.

Description

Technical Field

[0001] This application relates to the field of vehicles, and more specifically, to a method, apparatus, and storage medium for determining the exhaust valve closing phase in the field of vehicle engine technology. Background Technology

[0002] For hybrid systems that remove the VVT ​​(Variable Valve Timing) phaser, the engine exhaust valve closing phase can typically be determined in the following way:

[0003] (1) The optimal exhaust valve closing phase at the fuel consumption point is used as the exhaust valve closing phase for all speed external characteristics. Simulation and experimental verification are performed to obtain the power and torque performance of all speed external characteristics.

[0004] (2) The exhaust valve closing phase of the low-speed external characteristics is used as the exhaust valve closing phase of the medium- and high-speed external characteristics and fuel consumption point. Simulation and experimental verification are carried out to obtain the corresponding power, torque and fuel consumption performance.

[0005] (3) The exhaust valve closing phase of the high-speed external characteristics is used as the exhaust valve closing phase of the low-speed external characteristics and fuel consumption point. Simulation and experimental verification are carried out to obtain the corresponding power, torque and fuel consumption performance.

[0006] (4) Combining the fuel consumption performance of three different exhaust valve closing phases, the power and torque performance of the low-speed and medium-high speed external characteristics, the exhaust valve closing phase with better performance is selected by human intervention to determine the engine performance and fuel consumption performance.

[0007] However, the selection of the best exhaust valve closing phase in related technologies is subjective, which means that the selected exhaust valve closing phase is often not the optimal one, resulting in an inability to effectively balance power and fuel economy. Summary of the Invention

[0008] This application provides a method, apparatus, and storage medium for determining the exhaust valve closing phase. This method can determine the optimal exhaust valve closing phase of the engine by performing power and economy simulation analysis on the engine, based on the engine's power and economy requirements. This ensures that the engine performance meets the performance requirements of the vehicle while minimizing fuel consumption.

[0009] In a first aspect, a method for determining the exhaust valve closing phase is provided, the method comprising: obtaining the engine's power requirements and economic requirements; performing a power simulation on the engine based on the power requirements to obtain a first feasible range of the engine's exhaust valve closing phase; performing an economic simulation on the engine based on the economic requirements and the first feasible range to obtain candidate phases of the engine's exhaust valve closing phase; and determining the optimal exhaust valve closing phase of the engine based on the candidate phases.

[0010] Through the above technical solution, the embodiments of this application can start from the engine's power and economy requirements, and determine the optimal exhaust valve closing phase of the engine by conducting simulation analysis of the engine's power and economy. Thus, the optimal exhaust valve closing phase is determined through simulation, avoiding the influence of human subjective factors. The method of determining the exhaust valve closing phase is more rigorous and scientific, and can determine the optimal exhaust valve closing phase more accurately and efficiently. It also effectively takes into account both power and fuel economy, thereby ensuring that the engine performance meets the performance requirements of the whole vehicle while reducing fuel consumption to the minimum.

[0011] In conjunction with the first aspect, in some possible implementations, the step of performing a dynamic simulation of the engine based on the dynamic requirements to obtain a first feasible range of exhaust valve closing phases for the engine includes: acquiring vehicle dynamic-related parameters, performance operating points, and preset exhaust valve closing phases; performing a whole-vehicle performance simulation of the vehicle based on the dynamic-related parameters and the performance operating points, and identifying a first range of exhaust valve closing phases in the results of the whole-vehicle performance simulation that satisfy the dynamic requirements; performing an engine performance simulation of the engine based on the dynamic-related parameters and the preset exhaust valve closing phase, and identifying a second range of exhaust valve closing phases in the results of the engine performance simulation that satisfy the dynamic requirements; and taking the intersection of the first range and the second range as the first feasible range.

[0012] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the power-related parameters include one or more of the following: vehicle model, hybrid system architecture, vehicle mode control strategy, maximum vehicle speed, and maximum gradeability; the performance operating point includes the torque point and power point corresponding to the engine; the preset exhaust valve closing phase is the exhaust valve closing phase corresponding to the performance operating point before the engine removes the exhaust variable valve timing system.

[0013] Through the above technical solution, the embodiments of this application can take into account the power requirements of the engine, determine the first range of the exhaust valve closing phase based on the power-related parameters and performance operating points, and determine the second range of the exhaust valve closing phase centered on the exhaust valve closing phase corresponding to the performance operating point before removing the variable valve timing. The intersection between the two is selected as the first feasible range of the exhaust valve closing phase determined by the power requirements, which can better meet the power requirements of the hybrid system for the engine, so as to achieve the maximum performance that meets the requirements of the whole vehicle after the engine removes the exhaust VVT.

[0014] Combining the first aspect and the above-described implementation methods, in some possible implementation methods, an economic simulation of the engine is performed based on economic requirements and a first feasible range to obtain candidate phases for the exhaust valve closing phase of the engine. This includes: acquiring vehicle-related economic parameters; performing a whole-vehicle economic simulation of the engine based on the economic parameters; determining a fuel consumption operating point that meets the economic requirements based on the results of the whole-vehicle economic simulation; establishing a fuel consumption evaluation index based on the fuel consumption operating point; performing engine economic simulation of the engine within the first feasible range based on the fuel consumption evaluation index; and determining candidate phases for the exhaust valve closing phase that meet the economic requirements based on the results of the engine economic simulation.

[0015] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the economic-related parameters include one or more of the vehicle model, the architecture of the hybrid system, and the vehicle mode control strategy, and the fuel consumption operating point includes the torque point and power point corresponding to the speed that meets the economic requirements.

[0016] Through the above technical solution, the embodiments of this application can take into account the economic requirements of the engine, and based on the fuel consumption operating point that meets the economic requirements according to the relevant economic parameters, and combined with the established comprehensive fuel consumption evaluation index that integrates each fuel consumption operating point and its time proportion, determine the candidate phase of the exhaust valve closing phase that meets the economic requirements. The economic requirements of the engine are comprehensively considered so that the exhaust valve closing phase with the best fuel consumption performance can be found in the future, so as to achieve the lowest fuel consumption performance.

[0017] In combination with the first aspect and the above implementation methods, in some possible implementation methods, determining the optimal exhaust valve closing phase of the engine based on the candidate phase includes: obtaining the engine's performance operating point and fuel consumption operating point; determining a second feasible range of the exhaust valve closing phase based on the candidate phase and the performance operating point; establishing a fuel consumption evaluation index based on the fuel consumption operating point; optimizing within the second feasible range with the fuel consumption evaluation index as the target to obtain the optimal exhaust valve closing phase of the engine.

[0018] Through the above technical solution, the embodiments of this application can determine a second feasible range of exhaust valve closing phase based on the engine's performance operating point, fuel consumption operating point and candidate phase, establish a fuel consumption evaluation index in combination with the fuel consumption operating point, and determine the optimal exhaust valve closing phase of the engine within the second feasible range, which can ensure that the engine performance meets the performance requirements of the whole vehicle, while reducing fuel consumption to the lowest level.

[0019] In combination with the first aspect and the above implementation methods, in some possible implementation methods, determining the second feasible range of the exhaust valve closing phase based on the candidate phase and the performance operating point includes: obtaining the power and torque index requirements of the engine; at the exhaust valve closing moment, verifying the target performance operating point that meets the index requirements; and at the target performance operating point, determining the second feasible range of the exhaust valve closing phase centered on the candidate phase.

[0020] Through the above technical solution, the embodiments of this application can verify the target performance operating point at which the exhaust valve closing time can meet the engine power and torque index requirements for a selected performance operating point. Then, taking the candidate exhaust valve closing phase as the center, a second feasible range of exhaust valve closing phases that can meet the power and torque index requirements is determined, so as to realize the maximum power and torque performance that the engine can achieve as much as possible after removing the exhaust VVT, and to meet the power requirements of the whole vehicle to the greatest extent.

[0021] In combination with the first aspect and the above implementation methods, in some possible implementation methods, determining the second feasible range of the exhaust valve closing phase centered on the candidate phase includes: obtaining a preset angle range for the exhaust valve closing phase sweep test; and conducting the exhaust valve closing phase sweep test within the preset angle range centered on the candidate phase to obtain a second feasible range of the exhaust valve closing phase that meets the index requirements.

[0022] Through the above technical solution, the embodiments of this application can take the candidate exhaust valve closing phase as the center and conduct an exhaust valve closing phase sweep test within a certain angle range to determine the second feasible range of the exhaust valve closing phase. Within the second feasible range, the optimal exhaust valve closing phase of the engine is determined, which takes into account the comprehensive performance of the engine's torque and fuel consumption, and can reduce the engine's fuel consumption to the greatest extent.

[0023] Secondly, a device for determining the exhaust valve closing phase is provided. The device includes: an acquisition module for acquiring the power requirements and economic requirements of an engine; a first simulation module for performing a power simulation on the engine based on the power requirements to obtain a first feasible range of the exhaust valve closing phase of the engine; a second simulation module for performing an economic simulation on the engine based on the economic requirements and the first feasible range to obtain candidate phases of the exhaust valve closing phase of the engine; and a determination module for determining the optimal exhaust valve closing phase of the engine based on the candidate phases.

[0024] In conjunction with the second aspect, in some possible implementations, the first simulation module is further configured to acquire the vehicle's power-related parameters, performance operating points, and preset exhaust valve closing phases; perform whole-vehicle performance simulation on the vehicle based on the power-related parameters and the performance operating points, and identify a first range of exhaust valve closing phases in the whole-vehicle performance simulation results that satisfy the power requirements; perform engine performance simulation on the engine based on the power-related parameters and the preset exhaust valve closing phases, and identify a second range of exhaust valve closing phases in the engine performance simulation results that satisfy the power requirements; and take the intersection of the first range and the second range as the first feasible range.

[0025] In combination with the second aspect and the above implementation methods, in some possible implementation methods, the power-related parameters include one or more of the following: vehicle model, hybrid system architecture, vehicle mode control strategy, maximum vehicle speed, and maximum gradeability; the performance operating point includes the torque point and power point corresponding to the engine; the preset exhaust valve closing phase is the exhaust valve closing phase corresponding to the performance operating point before the engine removes the exhaust variable valve timing system.

[0026] In conjunction with the second aspect and the above implementation methods, in some possible implementation methods, the second simulation module is further configured to: acquire vehicle economy-related parameters; perform whole-vehicle economy simulation on the engine based on the economy-related parameters; determine the fuel consumption operating point that meets the economy requirements based on the results of the whole-vehicle economy simulation; establish a fuel consumption evaluation index based on the fuel consumption operating point; perform engine economy simulation on the engine within the first feasible range based on the fuel consumption evaluation index; and determine the candidate phase of the exhaust valve closing phase that meets the economy requirements based on the results of the engine economy simulation.

[0027] In combination with the second aspect and the above implementation methods, in some possible implementation methods, the economic-related parameters include one or more of the vehicle model, the architecture of the hybrid system and the vehicle mode control strategy, and the fuel consumption operating point includes the torque point and power point corresponding to the speed that meets the economic requirements.

[0028] In combination with the second aspect and the above implementation methods, in some possible implementation methods, the determining module is further used to obtain the engine's performance operating point and fuel consumption operating point; determine a second feasible range of the exhaust valve closing phase based on the candidate phase and the performance operating point; establish a fuel consumption evaluation index based on the fuel consumption operating point, and optimize within the second feasible range with the fuel consumption evaluation index as the target to obtain the optimal exhaust valve closing phase of the engine.

[0029] In combination with the second aspect and the above implementation methods, in some possible implementation methods, the determining module is further used to obtain the power and torque index requirements of the engine; at the time of exhaust valve closing, verify the target performance operating point that meets the index requirements among the performance operating points; at the target performance operating point, determine a second feasible range of the exhaust valve closing phase with the candidate phase as the center.

[0030] In combination with the second aspect and the above implementation methods, in some possible implementation methods, the determining module is further used to obtain a preset angle range for the exhaust valve closing phase scan test; with the candidate phase as the center, the exhaust valve closing phase scan test is performed within the preset angle range to obtain a second feasible range of the exhaust valve closing phase that meets the index requirements.

[0031] Thirdly, a computer-readable storage medium is provided that stores computer program code, which, when executed on a computer, causes the computer to perform the methods described in the first aspect or any possible implementation thereof. Attached Figure Description

[0032] Figure 1 This is a flowchart of the method for determining the exhaust valve closing phase according to an embodiment of the present invention;

[0033] Figure 2 This is an example diagram illustrating the engine operating condition distribution in terms of power performance according to one embodiment of the present invention;

[0034] Figure 3 This is an example diagram illustrating the engine operating condition distribution in terms of power performance, as described in another embodiment of the present invention.

[0035] Figure 4 This is an example diagram illustrating the engine operating condition distribution in EV mode according to an embodiment of the present invention;

[0036] Figure 5 This is an example diagram illustrating the engine operating condition distribution in terms of economic aspects according to an embodiment of the present invention;

[0037] Figure 6 This is an example diagram illustrating the engine operating condition distribution in terms of economic aspects, as described in another embodiment of the present invention;

[0038] Figure 7 This is a comparative diagram of the engine in use according to one embodiment of the present invention;

[0039] Figure 8 This is the engine torque diagram described in the embodiments of the present invention;

[0040] Figure 9 This is an example diagram showing the distribution of operating points of the engine as described in an embodiment of the present invention;

[0041] Figure 10 This is a detailed flowchart of a method for determining the exhaust valve closing phase according to an embodiment of the present invention;

[0042] Figure 11 This is a block diagram of the device for determining the exhaust valve closing phase according to an embodiment of the present invention. Detailed Implementation

[0043] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0044] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0045] Figure 1 This is a flowchart of the method for determining the exhaust valve closing phase provided in the embodiments of this application.

[0046] For example, such as Figure 1 As shown, the method for determining the exhaust valve closing phase includes the following steps:

[0047] In step S101, the engine's power requirements and economic requirements are obtained.

[0048] It should be noted that the engine in this application embodiment refers to the engine of a hybrid power system excluding the exhaust VVT. The function of the exhaust VVT is to adjust the crankshaft angle corresponding to the closing time of the exhaust valve, with a maximum operating range of 60 degrees and a typical operating angle of around 30-40 degrees to achieve different scavenging targets. Under low-speed external characteristics (maximum load of 1000-2000 rpm), the exhaust VVT is positioned further back, controlling the exhaust valve to close later, thereby creating an intake overlap period with the intake valve, achieving the scavenging function and improving low-speed torque.

[0049] Hybrid systems have lower requirements for low-speed engine torque, and the loss of low-speed performance after removing the exhaust VVT is acceptable. In the medium and high speed external characteristics (4000rpm to rated speed and maximum load), the exhaust VVT is positioned in the middle forward, controlling the exhaust valve to close relatively early, improving charging efficiency and increasing intake volume, thus ensuring the output of engine torque and power. In the medium and low speed and medium and low load conditions, the exhaust VVT is positioned in the middle forward phase, and the exhaust valve closes relatively early, balancing charging efficiency and residual exhaust gas in the cylinder to achieve optimal fuel consumption and minimum emissions.

[0050] In this embodiment, the requirements of the hybrid power system for the engine are completely different from those of the traditional passenger vehicle power system. The power requirement is significantly reduced, while the fuel economy requirement is significantly increased. Therefore, this embodiment makes corresponding adjustments to the specific technical route of the engine to meet the power and fuel economy requirements of the hybrid power engine.

[0051] Specifically, in terms of power demand, such as Figure 2 and Figure 3 As shown, during vehicle start-up and low-speed driving, the electric drive mode of the motor and battery is used for the vast majority of the time. Even during rapid acceleration from a standstill, the electric drive mode is used initially, and the engine gradually intervenes. It is generally not used at medium-low speeds (1000-2000rpm) under medium-high loads. Therefore, it is only necessary to ensure the minimum usage requirements. When the vehicle enters the high-speed driving stage, the hybrid system requires the engine to provide greater power. In this driving state, the engine direct drive mode is used. Based on the vehicle's driving resistance, there is a clear requirement for the engine's power and torque at medium and high speeds. With a certain margin, the power and torque target of the engine at medium and high speeds can be determined relatively clearly.

[0052] In terms of economic demand, such as Figure 4 , Figure 5 and Figure 6As shown, urban driving conditions, where vehicles are most frequently used, require constant start-stop and low-to-medium speed driving. In such cases, hybrid systems primarily operate in pure electric and series hybrid modes. The engine's demands are mainly on operation within the OOL (Out of Range) and at low to medium speeds and low loads. Minimizing overall engine fuel consumption and improving engine efficiency within this range will significantly improve the vehicle's fuel economy. The OOL line is the line connecting the lowest fuel consumption points at various engine power levels, representing the optimal fuel economy line.

[0053] Therefore, the main requirements for the engine in a hybrid system are to minimize fuel consumption at low and medium speeds and low loads, and to achieve a certain power and torque target at medium and high speeds and loads. Figure 7 This image shows a comparison of the engine usage areas for conventional and hybrid vehicles under a certain automaker's DHT system. The light white area represents the engine operating area for conventional vehicles, while the light gray area represents the engine operating area for hybrid DHT vehicles.

[0054] In step S102, the engine is subjected to dynamic simulation based on the power requirements to obtain the first feasible range of the exhaust valve closing phase of the engine.

[0055] Among them, dynamic simulation can include vehicle performance simulation and engine performance simulation.

[0056] It is understood that the embodiments of this application can simulate the engine to meet the power requirements, and quickly and accurately determine the feasible range of the exhaust valve closing phase through simulation.

[0057] In one embodiment of this application, a first feasible range of exhaust valve closing phases for the engine is obtained by performing a power performance simulation based on power performance requirements. This includes: acquiring vehicle power performance-related parameters, performance operating points, and preset exhaust valve closing phases; performing a whole-vehicle performance simulation based on the power performance-related parameters and performance operating points, and identifying a first range of exhaust valve closing phases that meet the power performance requirements in the results of the whole-vehicle performance simulation; performing an engine performance simulation based on the power performance-related parameters and preset exhaust valve closing phases, and identifying a second range of exhaust valve closing phases that meet the power performance requirements in the results of the engine performance simulation; and taking the intersection of the first range and the second range as the first feasible range.

[0058] Among them, the power-related parameters may include one or more of the following: vehicle model, hybrid system architecture, vehicle mode control strategy, maximum vehicle speed, and maximum gradeability; the performance operating point may include the torque point and power point corresponding to the engine; the preset exhaust valve closing phase is the exhaust valve closing phase corresponding to the engine's performance operating point before the exhaust variable valve timing system is removed.

[0059] It is understood that the embodiments of this application can first consider the engine's power requirements, and determine a first feasible range for the exhaust valve closing phase based on these power requirements. Wherein, such as Figure 8 As shown, the engine's power requirements mainly involve the engine's power and torque under medium-high speed and medium-high load conditions.

[0060] Specifically, in this embodiment, the high-speed torque point and power point can be selected as performance operating points. Based on vehicle parameters, hybrid system architecture and vehicle mode control strategy, as well as indicators such as the vehicle's maximum speed and maximum gradeability, the first range of exhaust valve closing phases that can meet the vehicle performance indicators such as engine maximum power and torque is determined through vehicle performance simulation analysis. Then, through engine performance simulation analysis, the exhaust valve closing phase is scanned near the exhaust valve closing phase corresponding to the performance operating point before VVT ​​is removed (usually 5-10 degrees of crankshaft angle) to determine the second range of exhaust valve closing phases that meet the power requirements in the engine performance simulation results. Finally, the intersection between the first range of exhaust valve closing phases determined by the performance simulation analysis and the second range of exhaust valve closing phases is selected as the first feasible range of exhaust valve closing phases determined by the power requirements.

[0061] For example, taking a 1.5T engine with the exhaust VVT removed as an example, the first range of the exhaust valve closing phase at the power point and torque point is -12degCA and -17degCA (the negative sign represents before top dead center). Taking the exhaust valve closing phase before removing the exhaust VVT as the center, after scanning points near this phase, the first feasible range is -20 to -10degCA.

[0062] In step S103, an economic simulation of the engine is performed based on economic requirements and the first feasible range to obtain candidate phases for the exhaust valve closing phase of the engine.

[0063] Among them, economic simulation can include vehicle economic simulation and engine economic simulation.

[0064] It is understood that the embodiments of this application can simulate the engine to meet economic requirements, and quickly and accurately determine the candidate phase of the exhaust valve closing phase within a first feasible range through simulation.

[0065] In one embodiment of this application, an economic simulation of the engine is performed based on economic requirements and a first feasible range to obtain candidate phases for the exhaust valve closing phase of the engine. This includes: acquiring economic-related parameters of the vehicle; performing a whole-vehicle economic simulation of the engine based on the economic-related parameters; determining a fuel consumption operating point that meets economic requirements based on the results of the whole-vehicle economic simulation; establishing a fuel consumption evaluation index based on the fuel consumption operating point; performing an engine economic simulation of the engine within the first feasible range based on the fuel consumption evaluation index; and determining candidate phases for the exhaust valve closing phase that meet economic requirements based on the results of the engine economic simulation.

[0066] Among them, the economic-related parameters include one or more of the vehicle model, the architecture of the hybrid system, and the vehicle mode control strategy, and the fuel consumption operating point includes the torque point and power point corresponding to the speed that meets the economic requirements.

[0067] It is understood that the embodiments of this application may take into account the economic requirements of the engine and determine the third range of the exhaust valve closing phase when the CFC (Combined Fuel Consumption Index) is at its lowest value based on the economic requirements.

[0068] Specifically, embodiments of this application can, based on vehicle parameters, hybrid system architecture, and vehicle mode control strategy, perform vehicle performance simulation analysis using road spectra used in relevant testing standards to determine the distribution of operating points that meet engine economy requirements throughout the entire test cycle, such as... Figure 9 As shown, based on the time proportion, 5-8 points with the largest proportion are selected as fuel consumption operating points. The fuel consumption operating points and their corresponding time proportions are integrated to establish a comprehensive fuel consumption evaluation index that integrates all fuel consumption operating points and their time proportions. Then, based on the first range of exhaust valve closing phase determined by power requirements, the candidate phase of exhaust valve closing phase at the lowest CFC value is determined through simulation analysis within the first feasible range.

[0069] A comprehensive fuel consumption evaluation index is established, which integrates various fuel consumption operating conditions and their time proportions. The formula is CFC = BSFC1 * TW1 + BSFC2 * TW2 ... , where CFC represents the comprehensive fuel consumption evaluation index, BSFCi represents the fuel consumption at the i-th operating condition, and TWi represents the time weight at the i-th point.

[0070] For example, taking a 1.5T engine without exhaust VVT as an example, the selected fuel consumption points and corresponding time weights are 1612rpm_93Nm@27%, 1875rpm_127Nm@21%, 2226rpm_135Nm@17%, 2622rpm_184Nm@16%, 2145rpm_107Nm@11%, and 2293rpm_203Nm@9%. Based on this, a sweep analysis is performed on the exhaust valve closing time under each operating condition, with a sweep range of -20 to -10 degrees CA. Finally, it is determined that the lowest CFC value occurs at -20 degrees CA, which is used as a candidate phase for the exhaust valve closing phase.

[0071] In step S104, the optimal exhaust valve closing phase of the engine is determined based on the candidate phases.

[0072] In one embodiment of this application, determining the optimal exhaust valve closing phase of an engine based on candidate phases includes: acquiring the engine's performance operating point and fuel consumption operating point; determining a second feasible range of exhaust valve closing phases based on candidate phases and performance operating points; establishing a fuel consumption evaluation index based on the fuel consumption operating point; optimizing the fuel consumption evaluation index within the second feasible range to obtain the optimal exhaust valve closing phase of the engine.

[0073] It is understandable that, after determining the candidate phases of the alternative exhaust valve closing phases, the embodiments of this application can be transferred to the whole machine test bench to carry out engine performance and fuel consumption test verification work in order to determine the optimal exhaust valve closing phase of the engine.

[0074] Specifically, based on the above embodiments, this application embodiment can determine the engine's performance operating point and fuel consumption operating point. First, for the selected performance operating point (engine high-speed torque point and power point), the target performance operating point is verified according to the engine's power and torque index requirements to ensure that the exhaust valve closing time meets the engine's power and torque index requirements. At the target performance operating point, this application embodiment can obtain a preset angle range for the exhaust valve closing phase sweep test. With the candidate phase as the center, the exhaust valve closing phase sweep test is performed within the preset angle range to determine a second feasible range of exhaust valve closing phase that can meet the power and torque index requirements.

[0075] The preset angle range can be set according to the actual situation, such as 5-10 degrees crankshaft angle, without specific limitation.

[0076] Furthermore, based on all selected fuel consumption operating points, this embodiment of the application can conduct exhaust valve closing phase sweep tests within the feasible range determined by engine power and torque bench tests, with the candidate exhaust valve closing phase as the center. The exhaust valve closing phase is optimized by comprehensively evaluating fuel consumption indicators, with the goal of achieving the lowest value of the engine's comprehensive fuel consumption evaluation indicators, and finding the optimal exhaust valve closing phase.

[0077] For example, taking a 1.5T engine without exhaust VVT as an example, at the performance operating points, namely the engine's high-speed torque and power points, a sweep of exhaust valve closing phase points is performed, centered at -20°CA. This determines a second feasible range of -20 to -10°CA, within which both high-speed torque and power points meet performance requirements. Based on this, according to the selected fuel consumption operating point, a sweep of points is performed again within the range of -20 to -10°CA, starting from the exhaust valve closing phase, to find the lowest CFC value. Finally, -20°CA is determined to be the optimal exhaust valve closing phase.

[0078] To address the power and fuel economy requirements of hybrid power systems, the engine in this embodiment is a hybrid power engine, and the exhaust VVT (Vehicle Valve Transmission Unit) in the prior art has been removed. After removing the exhaust VVT, the exhaust valve closing phase is set between 50°CA and -50°CA, preferably between -20°CA and -10°CA, the exhaust cam's wrap angle is 120-250°CA, and the exhaust valve lift range is 6-12mm. This maximizes the torque performance of the hybrid vehicle at medium-high speeds and under medium-high loads, minimizing overall fuel consumption.

[0079] The following will elaborate on the method for determining the exhaust valve closing phase through a specific implementation, such as... Figure 10 As shown, the main process is as follows:

[0080] Step 1: Determine the exhaust valve closing phase within the range of D1-D2 based on power requirements.

[0081] Specifically, the high-speed torque point and power point are selected as performance operating points. The exhaust valve closing phase is determined through performance simulation analysis. Then, taking the exhaust valve closing phase before removing VVT as the midpoint, the exhaust valve closing phase is scanned within a crankshaft angle range of 5-10 degrees. The intersection between the exhaust valve closing phase determined by the performance simulation analysis and the closing phase determined by the performance simulation analysis is selected as the range of the exhaust valve closing phase determined by the power performance.

[0082] Step 2: Determine the exhaust valve closing phase D3 when the CFC value is at its minimum based on economic requirements;

[0083] Specifically, based on vehicle parameters, hybrid system architecture, and vehicle mode control strategy, the vehicle performance is simulated and analyzed using the road spectrum used in national testing standards. This determines the distribution of engine operating conditions throughout the entire test cycle. Then, based on time weighting, 5-8 points with the largest proportion are selected as fuel consumption operating conditions. The fuel consumption points and their corresponding time proportions are integrated to establish a comprehensive fuel consumption evaluation index that integrates all fuel consumption operating conditions and their time proportions. Finally, based on the range of exhaust valve closing phase determined by power performance, the candidate exhaust valve closing phase at the lowest CFC value is determined through simulation analysis.

[0084] Step 3: After determining the candidate exhaust valve closing phases, transfer the engine to the test bench to conduct engine performance and fuel consumption tests to determine the optimal exhaust valve closing phase. This aims to achieve the maximum performance and lowest possible fuel consumption for the vehicle after removing the exhaust VVT from a conventional engine. As an example, fuel consumption improvements can be seen in Table 1.

[0085] Table 1

[0086]

[0087] In summary, the exhaust valve closing phase determination method of this application embodiment can determine the optimal exhaust valve closing phase by starting from the engine's power and fuel economy requirements and conducting simulation analysis of the engine's power and fuel economy. This method avoids the influence of subjective human factors and is more rigorous and scientific in determining the exhaust valve closing phase. It can determine the optimal exhaust valve closing phase more accurately and efficiently, and effectively balances power and fuel economy. Thus, while ensuring that the engine performance meets the performance requirements of the vehicle, fuel consumption is reduced to a minimum.

[0088] Figure 11 This is a schematic diagram of the structure of the exhaust valve closing phase determination device provided in the embodiments of this application.

[0089] For example, such as Figure 11 As shown, the device 10 may include: an acquisition module 100, a first simulation module 200, a second simulation module 300, and a determination module 400.

[0090] The acquisition module 100 is used to acquire the engine's power requirements and economic requirements; the first simulation module 200 is used to perform power simulation on the engine based on the power requirements to obtain a first feasible range of the engine's exhaust valve closing phase; the second simulation module 300 is used to perform economic simulation on the engine based on the economic requirements and the first feasible range to obtain candidate phases of the engine's exhaust valve closing phase; and the determination module 400 is used to determine the optimal exhaust valve closing phase of the engine based on the candidate phases.

[0091] In one embodiment of this application, the first simulation module 200 is further configured to acquire the vehicle's power-related parameters, performance operating points, and preset exhaust valve closing phases; perform whole-vehicle performance simulation on the vehicle based on the power-related parameters and performance operating points, and identify a first range of exhaust valve closing phases that meet the power requirements in the results of the whole-vehicle performance simulation; perform engine performance simulation on the engine based on the power-related parameters and preset exhaust valve closing phases, and identify a second range of exhaust valve closing phases that meet the power requirements in the results of the engine performance simulation; and take the intersection of the first range and the second range as the first feasible range.

[0092] In one embodiment of this application, the power-related parameters include one or more of the following: vehicle model, hybrid system architecture, vehicle mode control strategy, maximum vehicle speed, and maximum gradeability; the performance operating point includes the torque point and power point corresponding to the engine; and the preset exhaust valve closing phase is the exhaust valve closing phase corresponding to the engine's performance operating point before the exhaust variable valve timing system is removed.

[0093] In one embodiment of this application, the second simulation module 300 is further configured to: acquire vehicle economy-related parameters; perform whole-vehicle economy simulation on the engine based on the economy-related parameters; determine the fuel consumption operating point that meets the economy requirements based on the results of the whole-vehicle economy simulation; establish fuel consumption evaluation index based on the fuel consumption operating point; perform engine economy simulation on the engine within a first feasible range based on the fuel consumption evaluation index; and determine the candidate phase of the exhaust valve closing phase that meets the economy requirements based on the results of the engine economy simulation.

[0094] In one embodiment of this application, the economy-related parameters include one or more of the vehicle model, the architecture of the hybrid system, and the vehicle mode control strategy, and the fuel consumption operating point includes the torque point and power point corresponding to the speed that meets the economy requirements.

[0095] In one embodiment of this application, the determining module 400 is further configured to obtain the engine's performance operating point and fuel consumption operating point; determine a second feasible range of exhaust valve closing phase based on the candidate phase and performance operating point; establish a fuel consumption evaluation index based on the fuel consumption operating point; optimize the fuel consumption evaluation index within the second feasible range to obtain the engine's optimal exhaust valve closing phase.

[0096] In one embodiment of this application, the determining module 400 is further configured to obtain the power and torque requirements of the engine; at the time of exhaust valve closure, verify the target performance condition point that meets the requirements; and at the target performance condition point, determine a second feasible range of the exhaust valve closing phase centered on the candidate phase.

[0097] In one embodiment of this application, the determining module 400 is further configured to obtain a preset angle range for the exhaust valve closing phase scan test; with the candidate phase as the center, the exhaust valve closing phase scan test is performed within the preset angle range to obtain a second feasible range of exhaust valve closing phases that meet the index requirements.

[0098] In summary, the exhaust valve closing phase determination device of this application embodiment can determine the optimal exhaust valve closing phase of the engine by starting from the engine's power and fuel economy requirements and conducting simulation analysis of the engine's power and fuel economy. This method of determining the optimal exhaust valve closing phase through simulation avoids the influence of subjective human factors. The exhaust valve closing phase determination method is more rigorous and scientific, and can determine the optimal exhaust valve closing phase more accurately and efficiently. It also effectively balances power and fuel economy, thereby ensuring that the engine performance meets the performance requirements of the vehicle while minimizing fuel consumption.

[0099] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for determining the exhaust valve closing phase.

[0100] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0101] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "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 this application. 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0102] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for determining the exhaust valve closing phase, characterized in that, The method includes: Obtain the engine's power and fuel economy requirements; Based on the power requirements, a power simulation of the engine is performed to obtain a first feasible range of the exhaust valve closing phase of the engine; Based on the economic requirements and the first feasible range, the engine is subjected to economic simulation to obtain candidate phases for the exhaust valve closing phase of the engine. The optimal exhaust valve closing phase of the engine is determined based on the candidate phases; The step of performing a dynamic simulation of the engine based on the dynamic requirements to obtain a first feasible range of the exhaust valve closing phase of the engine includes: acquiring vehicle dynamic-related parameters, performance operating points, and a preset exhaust valve closing phase, wherein the dynamic-related parameters include one or more of the following: vehicle model, hybrid system architecture, vehicle mode control strategy, maximum vehicle speed, and maximum gradeability; the performance operating points include the torque point and power point corresponding to the engine; the preset exhaust valve closing phase is the exhaust valve closing phase corresponding to the performance operating point of the engine before removing the exhaust variable valve timing system; performing a whole-vehicle performance simulation of the vehicle based on the dynamic-related parameters and the performance operating points, and identifying a first range of exhaust valve closing phases that meet the dynamic requirements in the results of the whole-vehicle performance simulation; performing an engine performance simulation of the engine based on the dynamic-related parameters, with the preset exhaust valve closing phase as the center, scanning the exhaust valve closing phase within a preset crankshaft angle range, and identifying a second range of exhaust valve closing phases that meet the dynamic requirements in the results of the engine performance simulation; and taking the intersection of the first range and the second range as the first feasible range.

2. The method according to claim 1, characterized in that, The step of performing economic simulation on the engine based on the economic requirements and the first feasible range to obtain candidate phases for the exhaust valve closing phase of the engine includes: Obtain relevant economic parameters for the vehicle; Based on the economic parameters, a vehicle economy simulation is performed on the engine, and the fuel consumption condition point that meets the economic requirements is determined based on the results of the vehicle economy simulation. A fuel consumption evaluation index is established based on the fuel consumption operating point. An engine economy simulation is performed on the engine within the first feasible range based on the fuel consumption evaluation index. Based on the results of the engine economy simulation, a candidate phase for the exhaust valve closing phase that meets the economic requirements is determined.

3. The method according to claim 2, characterized in that, The economic-related parameters include one or more of the vehicle model, hybrid system architecture, and vehicle mode control strategy, and the fuel consumption operating point includes the torque point and power point corresponding to the speed that meets the economic requirements.

4. The method according to claim 1, characterized in that, Determining the optimal exhaust valve closing phase of the engine based on the candidate phase includes: Obtain the engine's performance and fuel consumption points; A second feasible range for the exhaust valve closing phase is determined based on the candidate phase and the performance operating point; Based on the fuel consumption operating point, a fuel consumption evaluation index is established, and the optimal exhaust valve closing phase of the engine is obtained by optimizing the fuel consumption evaluation index within the second feasible range.

5. The method according to claim 4, characterized in that, The step of determining a second feasible range for the exhaust valve closing phase based on the candidate phase and the performance operating point includes: Obtain the required power and torque specifications for the engine; At the moment the exhaust valve is closed, verify the target performance point that meets the index requirements among the performance operating points; At the target performance point, a second feasible range of the exhaust valve closing phase is determined with the candidate phase as the center.

6. The method according to claim 5, characterized in that, The second feasible range for determining the exhaust valve closing phase centered on the candidate phase includes: Obtain the preset crankshaft angle range for the exhaust valve closing phase sweep test; Centered on the candidate phase, a sweep test of the exhaust valve closing phase is performed within the preset crankshaft angle range to obtain a second feasible range of the exhaust valve closing phase that meets the index requirements.

7. A device for determining the closing phase of an exhaust valve, characterized in that, The device includes: The acquisition module is used to acquire the engine's power and economic requirements; The first simulation module is used to perform a dynamic simulation of the engine based on the dynamic requirements to obtain a first feasible range of the exhaust valve closing phase of the engine. The second simulation module is used to perform economic simulation of the engine based on the economic requirements and the first feasible range to obtain candidate phases of the exhaust valve closing phase of the engine. A determining module is used to determine the optimal exhaust valve closing phase of the engine based on the candidate phases; The first simulation module is used to acquire the vehicle's power-related parameters, performance operating points, and preset exhaust valve closing phase. The power-related parameters include one or more of the following: vehicle model, hybrid system architecture, vehicle mode control strategy, maximum speed, and maximum gradeability. The performance operating points include the engine's corresponding torque and power points. The preset exhaust valve closing phase is the exhaust valve closing phase corresponding to the performance operating point before the engine's exhaust variable valve timing system is removed. Based on the power-related parameters and the performance operating points, the module performs a whole-vehicle performance simulation of the vehicle, identifying a first range of exhaust valve closing phases in the simulation results that satisfy the power requirements. Based on the power-related parameters, and with the preset exhaust valve closing phase as the center, the module performs an exhaust valve closing phase sweep within a preset crankshaft angle range, and performs engine performance simulation of the engine, identifying a second range of exhaust valve closing phases in the simulation results that satisfy the power requirements. The intersection of the first range and the second range is taken as the first feasible range.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed, implements the method for determining the exhaust valve closing phase as described in any one of claims 1-6.

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