High-compression-ratio gas engine matching method and system

Abstract

The invention relates to a high-compression-ratio gas engine matching method and system, and the method comprises the steps: building a one-dimensional simulation model of a gas engine, and taking an initial geometric compression ratio, an initial intake valve lift curve and an initial exhaust valve lift curve as boundary conditions; based on a one-dimensional simulation model of the gas engine and universal working conditions of the engine, aiming at different set geometric compression ratios, gas inlet total parameters and gas exhaust total parameters are optimized, and a universal working condition effective compression ratio and universal working condition gas inlet and gas exhaust total parameter matching scheme meeting the lowest comprehensive oil consumption requirement under different road working conditions is obtained. According to the method, a parameter setting scheme which is most suitable for the geometric compression ratio of the engine and the intake and exhaust cam profile is determined, and collaborative optimization of the compression ratio and all parameters aiming at the common road working condition of the whole vehicle is achieved, so that the gas engine can achieve low-rotating-speed heat efficiency improvement through the high compression ratio; and the design matching of high compression ratio and low actual load can be realized through Miller cycle, so that the engine is superior to a pure high-compression-ratio engine type.

Description

Technical Field

[0001] This application relates to the field of engines, specifically to a matching method and system for a high compression ratio gas engine. Background Technology

[0002] To address the global pursuit of "carbon reduction, energy conservation, and environmental protection," improving engine thermal efficiency has always been a key focus. From a thermodynamic perspective, a high compression ratio leads to higher thermal efficiency because the gas is compressed more thoroughly during compression, allowing the heat released during combustion to be more effectively converted into mechanical work, reducing energy waste. Therefore, a higher compression ratio improves the efficiency of the engine's constant-volume heating cycle (Otto cycle). A high compression ratio also enhances power output. It causes the air-fuel mixture in the cylinder to generate higher combustion pressure, resulting in a greater force pushing the piston and thus increasing engine torque and power output. Especially at low speeds, a high compression ratio reduces pumping losses, making power response more direct.

[0003] However, a high compression ratio also leads to a surge in engine mechanical and thermal loads. The most direct consequence is more intense knocking at high compression ratios; the higher the compression ratio, the more pronounced the knocking tendency. Furthermore, a high compression ratio results in a significant increase in cylinder pressure and temperature at the end of compression. Core engine components such as pistons, connecting rods, cylinder blocks, and valves must withstand greater mechanical stress and thermal shock, increasing the risk of component wear, deformation, and even breakage, shortening engine life, and reducing reliability. Summary of the Invention

[0004] This application provides a high compression ratio gas engine matching method and system, which can solve the problems in the prior art where gas engines with high compression ratios are prone to knocking, resulting in reduced power and reduced engine thermal efficiency.

[0005] In a first aspect, embodiments of this application provide a high compression ratio gas engine matching method, which includes: A one-dimensional simulation model of the gas engine was established, with the initial intake valve lift curve and the initial exhaust valve lift curve as boundary conditions. Based on a one-dimensional simulation model of a gas engine and the universal operating conditions of the engine, the intake and exhaust full parameters are optimized for different geometric compression ratios to obtain the universal operating effective compression ratio and universal operating condition intake and exhaust full parameter matching scheme that meet the minimum requirements for comprehensive fuel consumption under different road conditions.

[0006] In conjunction with the first aspect, in one embodiment, the total intake parameters include intake valve opening time parameters, intake valve closing time parameters, intake valve lift parameters, and intake valve profile fullness parameters; the total exhaust parameters include exhaust valve opening time parameters, exhaust valve closing time parameters, exhaust valve lift parameters, and exhaust valve profile fullness parameters.

[0007] In conjunction with the first aspect, in one implementation, based on a one-dimensional simulation model of the gas engine and the engine's universal operating conditions, for different geometric compression ratios, the intake and exhaust full-volume parameters are optimized to obtain a universal operating condition effective compression ratio and universal operating condition intake and exhaust full-volume parameter matching scheme that meets the minimum comprehensive fuel consumption requirements under different road conditions. Specifically, this includes: Based on a one-dimensional simulation model of a gas engine and the universal operating conditions of the engine, the intake and exhaust valve timing parameters are optimized for different geometric compression ratios to obtain the universal operating effective compression ratio, universal operating condition intake and exhaust timing combination parameters, and corresponding geometric compression ratio that meet the minimum requirements for comprehensive fuel consumption. The intake and exhaust valve timing parameters include: intake valve opening time parameters, intake valve closing time parameters, exhaust valve opening time parameters, and exhaust valve closing time parameters. Based on the one-dimensional simulation model of the gas engine and the universal operating conditions of the engine, the corresponding geometric compression ratio and the optimized intake and exhaust valve timing scheme parameters, the intake and exhaust valve profile lift scheme parameters are optimized to obtain the universal operating effective compression ratio and universal operating condition intake and exhaust valve lift combination parameters that meet the minimum requirements of comprehensive fuel consumption. The lift scheme parameters include: intake valve lift parameters and exhaust valve lift parameters. Based on the one-dimensional simulation model of the gas engine and the universal operating conditions of the engine, the corresponding geometric compression ratio, and the optimized intake and exhaust valve timing and lift parameters, the intake valve profile fullness parameters and exhaust valve profile fullness parameters are optimized to obtain the universal operating effective compression ratio and universal operating condition intake and exhaust valve profile fullness combination parameters that meet the minimum requirements for comprehensive fuel consumption. Based on the geometric compression ratio under different road conditions, combined with the intake and exhaust timing parameters, intake and exhaust valve lift parameters, and intake and exhaust valve profile fullness parameters, a universal operating condition effective compression ratio and universal operating condition intake and exhaust full parameter matching scheme that meet the minimum requirements for comprehensive fuel consumption are obtained.

[0008] In conjunction with the first aspect, in one implementation, based on a one-dimensional simulation model of the gas engine and the universal operating conditions of the engine, the intake and exhaust valve timing parameters are optimized for different geometric compression ratios to obtain the universal operating effective compression ratio, universal operating condition intake and exhaust timing combination parameters, and corresponding geometric compression ratio that meet the minimum overall fuel consumption requirements. The intake and exhaust valve timing parameters include: intake valve opening time parameters, intake valve closing time parameters, exhaust valve opening time parameters, and exhaust valve closing time parameters, specifically including: Keeping the initial exhaust valve lift curve in the one-dimensional simulation model of the gas engine unchanged, for different geometric compression ratios, the optimal intake timing matching scheme that meets the minimum comprehensive fuel consumption requirement is obtained by orthogonally combining different intake valve opening time parameters and different intake valve closing time parameters. Keeping the initial intake valve lift curve in the one-dimensional simulation model of the gas engine unchanged, for different geometric compression ratios, the optimal exhaust timing matching scheme that meets the minimum comprehensive fuel consumption requirement is obtained by orthogonally combining different exhaust valve opening time parameters and different exhaust valve closing time parameters. For different geometric compression ratios, the optimal intake and exhaust timing matching scheme and corresponding geometric compression ratio parameters that meet the minimum overall fuel consumption requirement under universal operating conditions are obtained by orthogonally combining different intake valve opening time parameters, intake valve closing time parameters, exhaust valve opening time parameters, and exhaust valve closing time parameters.

[0009] In conjunction with the first aspect, in one implementation, based on a one-dimensional simulation model of the gas engine and the engine's universal operating conditions, corresponding geometric compression ratio, and optimized intake and exhaust valve timing parameters, the intake and exhaust valve lift parameters are optimized to obtain the universal operating effective compression ratio and universal operating intake and exhaust valve lift combination parameters that meet the minimum overall fuel consumption requirements. The lift parameters include: intake valve lift parameters and exhaust valve lift parameters, specifically including: Keeping the initial exhaust valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing parameters, the optimal intake timing matching scheme that meets the minimum comprehensive fuel consumption requirement under universal operating conditions is obtained by setting different intake valve lift parameters. Keeping the initial intake valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing parameters, the optimal exhaust timing matching scheme that meets the minimum comprehensive fuel consumption requirement under universal operating conditions is obtained by setting different exhaust valve lift parameters. Based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing parameters, the optimal intake and exhaust valve lift matching scheme that meets the minimum overall fuel consumption requirement under universal operating conditions is obtained by orthogonally combining different intake valve lift parameters and different exhaust valve lift parameters.

[0010] In conjunction with the first aspect, in one implementation, based on a one-dimensional simulation model of the gas engine and the engine's universal operating conditions, corresponding geometric compression ratio, and optimized intake and exhaust valve timing and lift parameters, the intake valve profile fullness parameters and exhaust valve profile fullness parameters are optimized to obtain the universal operating effective compression ratio and universal operating intake and exhaust valve profile fullness combination parameters that meet the minimum requirements for comprehensive fuel consumption. Specifically, this includes: Keeping the initial exhaust valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing and lift parameters, the optimal intake fullness matching scheme for universal operating conditions that meets the minimum requirements of comprehensive fuel consumption is obtained. Keeping the initial intake valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing and lift parameters, the optimal exhaust fullness matching scheme that meets the minimum comprehensive fuel consumption requirement under universal operating conditions is obtained by setting different exhaust valve profile fullness parameters.

[0011] In conjunction with the first aspect, in one implementation, the universal operating condition effective compression ratio and universal operating condition intake and exhaust full parameter matching scheme corresponding to each road condition can achieve optimal overall vehicle fuel consumption while meeting torque target, EGR rate target, transient response target, knock evaluation target and not exceeding various boundary limits required by the engine.

[0012] In conjunction with the first aspect, in one embodiment, after obtaining the universal operating condition effective compression ratio and universal operating condition intake and exhaust full-volume parameter matching scheme that meet the minimum comprehensive fuel consumption requirements under different road conditions, the method further includes: At least one candidate scheme is selected from the full parameter matching scheme of intake and exhaust under universal operating conditions for prototype testing and verification. Each candidate scheme includes different compression ratios and corresponding combinations of intake and exhaust camshaft parameters. For each candidate scheme, the operating condition is determined to be either idling or non-idling by identifying the engine throttle opening and speed signals. Under idling conditions, the throttle opening and boost pressure are kept at the set values, and the EGR valve opening and ignition angle are adjusted to obtain the optimal specific air consumption parameters. Under non-idle conditions, the throttle opening and boost pressure are set according to different operating conditions, and the optimal specific air consumption parameters are obtained by modifying the EGR valve opening and ignition angle. The test data of each candidate scheme under various operating conditions are calibrated and iteratively optimized with the one-dimensional simulation model of the gas engine until the final matching scheme that is consistent with the simulation and test results and satisfies the optimal comprehensive fuel consumption is obtained.

[0013] In conjunction with the first aspect, in one implementation method, the test data of each candidate scheme under various operating conditions are calibrated and iteratively optimized with the one-dimensional simulation model of the gas engine, specifically including: The performance-related parameters obtained from the experiment, including the optimal specific gas consumption, are compared with the predicted data from the simulation model to calculate the relative error of the performance data. When the relative error of all performance data is less than the preset threshold, and the conclusions of the simulation and the experiment are consistent, the compression ratio and intake and exhaust camshaft parameters of the current candidate scheme are used as the final matching optimization scheme. Otherwise, the simulation model parameters are adjusted based on error feedback, and the iteration is repeated until the final matching solution is obtained.

[0014] Secondly, embodiments of this application provide a high compression ratio gas engine matching system, which includes: a first module and a second module. The first module is used to establish a one-dimensional simulation model of the gas engine and use the initial intake valve lift curve and the initial exhaust valve lift curve as boundary conditions. The second module is used to optimize the total intake and exhaust parameters based on the one-dimensional simulation model of the gas engine and the universal operating conditions of the engine, for different geometric compression ratios, to obtain the universal operating condition effective compression ratio and universal operating condition intake and exhaust parameter matching scheme that meet the minimum requirements of comprehensive fuel consumption under different road conditions. It also includes a third module, which is used for iterative interaction between experiment and simulation. The optimal matching scheme obtained from the simulation is used for experimental verification. The experimental results are further compared with the simulation results for calibration and model optimization. The final matching scheme is not only the optimized scheme output by the simulation, but can also be verified by the experiment.

[0015] The beneficial effects of the technical solutions provided in this application include: This application provides a high compression ratio gas engine matching method and system. By establishing a one-dimensional simulation model of the gas engine and using the initial geometric compression ratio, initial intake valve and exhaust valve lift curves as boundary conditions, based on the universal operating conditions of the engine, the total intake and exhaust parameters are optimized for different geometric compression ratios. The optimal parameter setting scheme for the geometric compression ratio and intake and exhaust cam profiles of the engine is determined. This achieves coordinated optimization of compression ratio and total parameters for common road conditions of the vehicle. The gas engine can achieve improved thermal efficiency at low speeds through high compression ratio, and can also achieve design matching of high compression ratio and low actual load through Miller cycle. This allows the engine to operate efficiently without compromising reliability and durability, and is even superior to simply high compression ratio engines. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the high compression ratio gas engine matching method of this application; Figure 2 This is a schematic diagram illustrating the specific process of step 102 in the high compression ratio gas engine matching method of this application. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0018] This application provides a high compression ratio gas engine matching method and system, which can solve the problems in the prior art where gas engines with high compression ratios are prone to knocking, resulting in reduced power and reduced engine thermal efficiency.

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0020] In a first aspect, embodiments of this application provide a high compression ratio gas engine matching method, which includes: Step 101: Establish a one-dimensional simulation model of the gas engine, and use the initial intake valve lift curve and the initial exhaust valve lift curve as boundary conditions; Step 102: Based on the one-dimensional simulation model of the gas engine and the universal operating conditions of the engine, optimize the total intake and exhaust parameters for different geometric compression ratios to obtain the universal operating condition effective compression ratio and universal operating condition intake and exhaust parameter matching scheme that meet the minimum requirements of comprehensive fuel consumption under different road conditions.

[0021] This application establishes a one-dimensional simulation model of a gas engine and uses the initial geometric compression ratio, initial intake valve lift curves, and exhaust valve lift curves as boundary conditions. Based on the engine's universal operating conditions, it optimizes the total intake and exhaust parameters for different geometric compression ratios, determining the most suitable parameter setting scheme for the engine's geometric compression ratio and intake and exhaust cam profiles. This achieves coordinated optimization of compression ratio and all parameters for common road conditions of the vehicle, enabling the gas engine to achieve both high compression ratio and low speed thermal efficiency improvement, and high compression ratio and low actual load design matching through Miller cycle. This allows the engine to operate efficiently without compromising reliability and durability, and even outperforms purely high compression ratio engines.

[0022] The intake full volume parameters include intake valve opening time parameter IVO, intake valve closing time parameter IVC, intake valve lift parameter IVL, and intake valve profile fullness parameter IVF; the exhaust full volume parameters include exhaust valve opening time parameter EVO, exhaust valve closing time parameter EVC, exhaust valve lift parameter EVL, and exhaust valve profile fullness parameter EVF.

[0023] Step 101: Establish a one-dimensional simulation model of the gas engine, using the initial geometric compression ratio, initial intake valve lift curve, and initial exhaust valve lift curve as boundary conditions. The specific steps are as follows: First, based on the engine development goals, the basic modeling data (such as engine geometric parameters, fuel characteristics, and performance calibration data) and their corresponding performance calibration data for the corresponding engine model are identified. A one-dimensional simulation model of the gas engine is established to ensure that the model matches the actual physical characteristics of the engine. The calibration conditions are representative universal characteristics, covering the entire speed range and load range of the engine, especially key performance nodes such as the maximum torque point, the maximum power point, and the optimal economy point. The simulation results calculated by the simulation model are compared with the experimental data to ensure that the simulation error is within ±5%. The smaller the error, the better the model calibration results match the experimental data, ensuring that the model provides a high-precision prediction basis in subsequent parameter optimization and has more accurate guidance for further optimization simulation and prediction based on the basic model.

[0024] Then set the initial geometric compression ratio, which can be set to CR+1, CR+2, CR+3, etc. based on the basic model compression ratio CR. The compression ratio setting needs to take into account the engine material strength and combustion stability. Usually, each time the compression ratio is increased by 1 unit, its impact on knock tendency needs to be verified to ensure that abnormal combustion is avoided while improving thermal efficiency.

[0025] Finally, initial intake and exhaust valve lift curves are set. These initial curves are typically based on a standard camshaft design, but different profiles can be selected depending on the engine type. For example, a gentler profile can be used for high-revving engines to reduce valve impact. The initial intake and exhaust valve lift curves are then input as boundary conditions into the simulation model, providing a benchmark for subsequent parameter optimization.

[0026] Based on the above embodiments, in this embodiment, based on the one-dimensional simulation model of the gas engine and the universal operating conditions of the engine, the intake parameters and exhaust volume parameters are optimized for different geometric compression ratios to obtain the universal operating condition effective compression ratio and universal operating condition intake and exhaust volume parameter matching scheme that meet the minimum requirements of comprehensive fuel consumption under different road conditions. Specifically, this includes steps 1021 to 1024: Step 1021: Based on the one-dimensional simulation model of the gas engine and the universal operating conditions of the engine, optimize the intake and exhaust valve timing parameters for different geometric compression ratios to obtain the effective compression ratio, intake and exhaust timing combination parameters, and corresponding geometric compression ratio that meet the minimum overall fuel consumption requirements. The intake and exhaust valve timing parameters include: intake valve opening time parameters, intake valve closing time parameters, exhaust valve opening time parameters, and exhaust valve closing time parameters. By precisely adjusting the intake and exhaust valve timing, the charging efficiency of the engine under different speeds and loads can be optimized, resulting in more complete combustion, effectively reducing fuel consumption, and avoiding knocking and excessive heat load caused by improper timing, thereby improving the reliability and durability of the engine.

[0027] Specifically, it includes: Step 10211: Keeping the initial exhaust valve lift curve in the one-dimensional simulation model of the gas engine unchanged, for different geometric compression ratios, orthogonal combination optimization is performed by setting different intake valve opening time parameters and different intake valve closing time parameters to obtain the optimal intake timing matching scheme that meets the minimum overall fuel consumption requirement under universal operating conditions. Orthogonal combination optimization is a systematic parameter optimization method. By conducting combined tests on multiple parameter dimensions, the optimal parameter combination can be found in a fewer number of experiments, avoiding the inefficiency of traditional single-factor adjustment methods. This ensures that the optimal intake timing parameter combination is obtained with limited computational resources, enabling the engine to achieve the best charging and combustion efficiency under different compression ratio conditions.

[0028] Specifically, taking compression ratio = CR as an example: When the compression ratio = CR, timing optimization based on the basic profile valve lift curve: This involves keeping the initial exhaust valve lift curve constant while optimizing intake timing. By setting different IVO and IVC times orthogonally, optimal intake timing matching schemes under different universal operating conditions can be obtained. For example, for operating condition 1, the optimal intake timing matching scheme is f1(IVO, IVC); for operating condition 2, it is f2(IVO, IVC), and so on, until operating condition k, where the optimal intake timing matching scheme is fk(IVO, IVC). The universal operating condition refers to the comprehensive operating state of the engine under different speeds and loads. By considering the universal operating condition, the engine's performance under various actual operating conditions can be comprehensively evaluated, ensuring that the optimization results are applicable not only to specific operating conditions but also to the entire operating range of the engine, avoiding performance degradation under other operating conditions caused by optimization of a single operating condition. Meanwhile, the effective compression ratio refers to the actual compression ratio exhibited by the engine under actual operating conditions after considering the influence of valve timing. Since changes in valve timing affect intake charge and residual exhaust gas, the actual effective compression ratio is not entirely consistent with the geometric compression ratio. By optimizing the timing, the effective compression ratio can be adjusted while keeping the geometric compression ratio constant, thereby achieving the best thermal efficiency under different operating conditions.

[0029] The comprehensive intake and exhaust parameter matching scheme for each road condition, in addition to meeting the minimum overall fuel consumption requirement, must also simultaneously meet torque targets, EGR rate targets, transient response targets, knock evaluation targets, and engine boundary limits. Specifically, the transient response target must meet the engine development target requirements; the knock evaluation target must not exceed the knock level of the base engine; and the engine boundary limits include turbocharger speed limits, post-compression temperature limits, and exhaust temperature limits. Through parameter optimization under multi-objective constraints, it is ensured that the engine meets requirements for fuel economy while also satisfying power, emissions, and reliability requirements. This avoids the degradation of other performance indicators caused by single-objective optimization. For example, simply pursuing low fuel consumption may lead to poor transient response or increased knock risk; multi-objective optimization can find the optimal balance point.

[0030] Then, since the target engine model is equipped with different vehicles and frequently encounters representative common vehicle road conditions in actual use, these conditions are different due to the integration of various factors such as vehicle speed, load, road conditions, and driving behavior. Therefore, to comprehensively evaluate the overall fuel consumption of the gas engine, it is necessary to use the actual common vehicle road conditions 1, 2…n as one-dimensional simulation conditions. Different road conditions correspond to different proportions of universal conditions. For example, under road condition 1, the comprehensive optimal fuel consumption under the optimal intake timing matching scheme fk(IVO, IVC) input for different conditions is calculated. min=fk(IVO, IVC), thus obtaining the universal effective compression ratio and universal intake timing matching scheme for the entire vehicle under road conditions. The proportion of road conditions reflects the frequency of different usage scenarios. Frequently used conditions have a high proportion, while infrequently used conditions have a low proportion. By calculating the comprehensive fuel consumption using weighted averages, we can ensure that the optimization results are closer to actual usage scenarios, so that the engine performs best under frequently encountered conditions, rather than only under specific conditions.

[0031] Similarly, the optimal fuel consumption for the vehicle under common road conditions 2, 3, 4...n can be obtained. Multi-condition comprehensive optimization ensures that the engine achieves optimal economy under various real-world usage scenarios, avoiding suboptimal overall fuel consumption caused by optimizing only a single condition. Similarly, by setting compression ratios CR+1, CR+2, ... and iteratively optimizing using the above method, the optimal combined fuel consumption for different compression ratios can be obtained. By systematically adjusting the compression ratio, the optimal balance between combined fuel consumption, power performance, and reliability can be found, avoiding reliability issues caused by simply increasing the compression ratio. For example, an excessively high compression ratio may increase the risk of knocking. Through system optimization, the optimal compression ratio that improves thermal efficiency while ensuring reliability can be found.

[0032] Step 10212: Keeping the initial intake valve lift curve in the one-dimensional simulation model of the gas engine unchanged, for different geometric compression ratios, orthogonally combine different exhaust valve opening and closing time parameters to obtain the optimal exhaust timing matching scheme that meets the minimum overall fuel consumption requirement under universal operating conditions. By fixing the total intake parameters and specifically optimizing the exhaust timing, the impact of the total exhaust parameters on engine performance can be evaluated, avoiding mutual interference between intake and exhaust parameters, making the optimization process more systematic and precise, ensuring that the best match between exhaust timing and compression ratio is found, thereby improving thermal efficiency while reducing the risk of knocking, forming an exhaust timing optimization path independent of the total intake parameters.

[0033] In this step, keeping the initial intake valve lift curve unchanged, the exhaust timing is optimized. Similar to obtaining the optimal intake timing matching scheme for the universal operating condition that meets the minimum overall fuel consumption requirement, the optimal exhaust timing fk(EVO, EVC) under different road conditions can be obtained. Each road condition corresponds to a set of optimal exhaust timing parameter combinations, reflecting the best matching relationship between exhaust timing and compression ratio under that condition. The corresponding optimal overall fuel consumption BSFC is also obtained. min=fk(EVO, EVC), the optimal combined fuel consumption is calculated from multiple values ​​for different compression ratios and parameter combinations. Each compression ratio and parameter combination produces a corresponding combined fuel consumption value. By comparing these values, the parameter combination that minimizes combined fuel consumption can be found, ensuring optimal overall economy of the engine in actual use. This yields the optimal exhaust timing matching scheme for universal operating conditions that meets the minimum combined fuel consumption requirement, i.e., the effective compression ratio and exhaust timing scheme for the universal operating conditions of this vehicle. This universal exhaust timing scheme, tailored to specific road conditions, combines the optimal matching combination of compression ratio and exhaust timing to ensure that the engine maintains optimal economy under these conditions while meeting multiple objective requirements such as torque, EGR rate, transient response, and knock evaluation, avoiding the degradation of other performance indicators caused by optimizing a single parameter.

[0034] Step 10213: For different geometric compression ratios, orthogonally combine different intake valve opening timing parameters, intake valve closing timing parameters, exhaust valve opening timing parameters, and exhaust valve closing timing parameters to obtain the optimal intake and exhaust timing matching scheme and corresponding geometric compression ratio parameters that meet the minimum overall fuel consumption requirements under universal operating conditions. By simultaneously optimizing intake and exhaust timing, the synergistic effect between all intake and exhaust parameters can be systematically analyzed, avoiding parameter mismatch problems that may occur if intake or exhaust timing is optimized alone. This allows the engine to achieve optimal charging and combustion efficiency under various operating conditions, thereby further reducing overall fuel consumption. At the same time, it avoids the decline in other performance indicators caused by optimizing a single parameter, improving the overall performance of the engine.

[0035] Simultaneous optimization of intake and exhaust timing yields the optimal intake and exhaust timing fk(IVO, IVC, EVO, EVC) for different road conditions. Each road condition corresponds to a set of optimal intake and exhaust timing parameter combinations. Matching these parameters optimizes the engine's intake and exhaust processes, making intake and exhaust volumes more coordinated, reducing airflow interference, improving charging efficiency, and thus reducing fuel consumption. It also avoids incomplete combustion or incomplete exhaust caused by mismatched intake and exhaust parameters. The corresponding comprehensive optimal fuel consumption BSFCmin=fk(IVO, IVC, EVO, EVC) is also obtained. This comprehensive optimal fuel consumption is a weighted average fuel consumption considering the weights of different road conditions, reflecting the overall economic performance of this intake and exhaust timing combination in real-world usage scenarios, rather than being optimal only under a single condition. This ensures the engine achieves optimal economy under common road conditions while meeting multi-objective optimization requirements. Thus, the universal effective compression ratio and universal exhaust timing scheme for this vehicle under various road conditions are obtained. The universal exhaust timing solution is designed for specific road conditions. It combines the optimal matching of compression ratio and intake and exhaust timing to ensure that the engine maintains the best economy under the conditions, while also meeting multiple objectives such as torque, EGR rate, transient response and knock evaluation. It avoids performance imbalance caused by optimizing a single parameter and achieves the optimization of comprehensive performance.

[0036] It should be noted that, based on actual needs and constraints, any of the solutions in steps 10211-10213 can be selected for parameter optimization. The specific solutions implemented depend on real-world constraints such as resources, cost, and the internal layout of the engine. In practical applications, due to differences in the structure, development cycle, and cost budgets of different engine platforms, it is necessary to select the most suitable optimization solution based on the actual situation to avoid unnecessary resource waste and development risks.

[0037] Step 1022: Based on the one-dimensional simulation model of the gas engine and the engine's universal operating conditions, corresponding geometric compression ratio, and optimized intake and exhaust valve timing parameters, optimize the intake and exhaust valve lift parameters to obtain the universal operating effective compression ratio and universal operating condition intake and exhaust valve lift combination parameters that meet the minimum requirements for overall fuel consumption. The lift parameters include intake valve lift parameters and exhaust valve lift parameters. By adjusting the valve lift, the intake and exhaust flow rates can be controlled, enabling the engine to achieve optimal charging efficiency under different loads. This avoids incomplete combustion or incomplete exhaust caused by improper valve lift, thereby optimizing overall fuel consumption and improving engine power output and response speed.

[0038] Specifically, it includes: Step 10221: Keeping the initial exhaust valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing parameters, the optimal intake timing matching scheme that meets the minimum overall fuel consumption requirement under universal operating conditions is obtained by setting different intake valve lift parameters. By fixing the exhaust parameters and specifically optimizing the intake lift, the impact of intake lift on engine performance can be independently evaluated, avoiding mutual interference between intake and exhaust parameters, making the optimization process more systematic and precise. This ensures that the best match between intake lift and compression ratio is found under limited computational resources, thereby improving thermal efficiency while optimizing charging efficiency, reducing intake resistance, improving engine combustion efficiency, and effectively reducing fuel consumption.

[0039] In this step, by keeping the exhaust profile unchanged and optimizing the intake lift, the optimal exhaust timing fk(IVL) for different road conditions can be obtained. Each road condition corresponds to a set of optimal intake lift parameters. By adjusting the IVL, the intake volume can be precisely controlled, ensuring that the engine achieves optimal charging efficiency under different loads. This avoids insufficient or excessive intake caused by improper valve lift, thereby optimizing the combustion process and reducing fuel consumption. The corresponding comprehensive optimal fuel consumption BSFCmin=fk(IVL) can also be obtained. The comprehensive optimal fuel consumption is a weighted average fuel consumption considering the weights of different road conditions. It reflects the overall economic performance of this intake lift parameter combination in actual use scenarios, rather than being optimal only under a single condition. This ensures that the engine achieves optimal economy under common road conditions while meeting multi-objective optimization requirements. Thus, the universal effective compression ratio and universal intake lift scheme for the entire vehicle under various road conditions are obtained. For specific road conditions, the optimal combination of compression ratio and intake lift is combined to ensure that the engine maintains the best economy under the conditions, while meeting multiple objectives such as torque, EGR rate, transient response and knock evaluation. This avoids the performance imbalance caused by optimizing a single parameter and achieves the optimization of comprehensive performance.

[0040] Step 10222: Keeping the initial intake valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing parameters, the optimal exhaust valve lift parameter is set to obtain the optimal exhaust timing matching scheme under universal operating conditions that meets the minimum overall fuel consumption requirement. By fixing the intake parameters and specifically optimizing the exhaust lift, the impact of exhaust lift on engine performance can be independently evaluated, avoiding mutual interference between intake and exhaust parameters. This makes the optimization process more systematic and precise, ensuring that the best match between exhaust lift and compression ratio is found within limited computational resources. This improves thermal efficiency while optimizing exhaust efficiency, reducing exhaust resistance, increasing engine charging efficiency, and effectively reducing fuel consumption.

[0041] In this step, keeping the initial intake valve lift curve unchanged, optimizing the exhaust lift yields the optimal exhaust timing fk(EVL) for different road conditions. Each road condition corresponds to a set of optimal exhaust lift parameters, where EVL reflects the best matching value of the exhaust valve opening height under that condition. By adjusting EVL, the exhaust volume can be precisely controlled, ensuring the engine achieves optimal exhaust efficiency under different loads. This avoids insufficient or excessive exhaust due to improper valve lift, thereby optimizing the combustion process and reducing fuel consumption. The corresponding comprehensive optimal fuel consumption BSFCmin=fk(EVL) can also be obtained, leading to the universal effective compression ratio and universal exhaust lift scheme for the vehicle under various road conditions. The universal exhaust lift scheme combines the optimal matching of compression ratio and exhaust lift for specific road conditions, ensuring the engine maintains optimal economy while meeting multiple objectives such as torque, EGR rate, transient response, and knock evaluation. This avoids performance imbalances caused by optimizing a single parameter, achieving optimal overall performance.

[0042] Step 10223: Based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing parameters, an optimal intake and exhaust valve lift matching scheme that meets the minimum overall fuel consumption requirement under universal operating conditions is obtained by orthogonally combining different intake and exhaust valve lift parameters. By simultaneously optimizing intake and exhaust lift, the synergistic effect between intake and exhaust parameters can be systematically analyzed, avoiding parameter mismatch problems that may occur if intake or exhaust lift is optimized alone. This allows the engine to achieve optimal charging and combustion efficiency under various operating conditions, thereby further reducing overall fuel consumption. Simultaneously, it avoids the decline in other performance indicators caused by optimizing a single parameter, improving the overall performance of the engine.

[0043] In this step, the intake and exhaust profile lifts are optimized simultaneously to obtain the optimal exhaust timing fk(IVL, EVL) under different road conditions. Each road condition corresponds to a set of optimal intake and exhaust lift parameter combinations. Matching these parameters can optimize the engine's intake and exhaust processes, making the intake and exhaust volumes more coordinated, reducing airflow interference, improving charging efficiency, and thus reducing fuel consumption. At the same time, it avoids incomplete combustion or incomplete exhaust caused by mismatched intake and exhaust parameters, ensuring that the engine can obtain the best charging efficiency under different loads.

[0044] The corresponding optimal fuel consumption BSFCmin=fk(IVL, EVL) can also be obtained. The optimal fuel consumption is a weighted average fuel consumption that takes into account the weights of different road conditions. It reflects the overall economic performance of the intake and exhaust lift combination in actual use scenarios, rather than just performing best under a single condition. It ensures that the engine achieves the best economy under common road conditions and meets the requirements of multi-objective optimization. Through weight calculation, the impact of common conditions on the overall fuel consumption is made greater and closer to actual use.

[0045] This yields the optimal intake and exhaust lift matching scheme for universal operating conditions that meets the minimum requirements for overall fuel consumption. This is the universal effective compression ratio and universal intake and exhaust lift scheme for the vehicle under specific road conditions. The universal intake and exhaust lift scheme is designed for specific road conditions, combining the optimal matching of compression ratio and intake / exhaust lift to ensure that the engine maintains optimal economy while meeting multiple objectives such as torque, EGR rate, transient response, and knock evaluation. It avoids performance imbalances caused by optimizing a single parameter, achieving optimal overall performance and ensuring the engine achieves the best balance between economy and reliability in various usage scenarios.

[0046] It should be noted that, based on actual needs and constraints, any of the solutions in steps 10221-10223 can be selected for parameter optimization. The specific solutions implemented depend on real-world constraints such as resources, cost, and the internal layout of the engine. During engine development, different optimization solutions exhibit varying computational complexity and implementation difficulty. Appropriate selection of optimization solutions can effectively balance development efficiency and optimization effectiveness, avoiding resource waste and extended development cycles caused by over-optimization. When resources are limited, steps 10221 or 10222 are preferred as the basic optimization scheme because these two schemes have relatively small computational load and can obtain preliminary optimization results in a short time, providing a reference basis for subsequent more complex optimizations. This avoids excessive consumption of computational resources caused by directly performing multi-parameter collaborative optimization, improves development efficiency, and ensures the reliability of optimization results. If cost allows, step 10223 can be selected. Although this approach involves more computation, it achieves better overall performance and is particularly suitable for engine development projects with high economic requirements. By coordinating the optimization of intake and exhaust lift, the performance requirements of the engine under different operating conditions can be more comprehensively matched, achieving better overall fuel consumption while meeting multi-objective optimization requirements.

[0047] Step 1023: Based on the one-dimensional simulation model of the gas engine and its universal operating conditions, corresponding geometric compression ratio, and optimized intake and exhaust valve timing and lift parameters, optimize the intake and exhaust valve profile fullness parameters to obtain the universal operating effective compression ratio and universal operating condition intake and exhaust valve profile fullness combination parameters that meet the minimum requirements for comprehensive fuel consumption. By adjusting the valve profile fullness, the airflow characteristics during valve opening can be optimized, airflow losses reduced, and intake and exhaust efficiency improved. Especially under high load conditions, this can effectively reduce knock tendency, improve engine reliability, and improve engine NVH performance.

[0048] Specifically, it includes: Step 10231: Keeping the initial exhaust valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing and lift parameters, obtain the optimal intake fullness matching scheme for universal operating conditions that meets the minimum overall fuel consumption requirements. By fixing the exhaust parameters and specifically optimizing the intake valve profile fullness, the impact of valve opening shape on engine performance can be independently evaluated, avoiding mutual interference between intake and exhaust parameters. This makes the optimization process more systematic and precise, ensuring that the best match between intake profile fullness and compression ratio is found with limited computational resources. This improves thermal efficiency while optimizing intake flow characteristics, reducing airflow losses, increasing engine charging efficiency, and effectively reducing fuel consumption.

[0049] By keeping the initial exhaust valve lift curve constant and optimizing the intake fullness, the optimal exhaust timing fk (IVF) under different road conditions can be obtained. Each road condition corresponds to a set of optimal intake profile fullness parameters, where IVF is the intake valve profile fullness, which reflects the best matching value of the intake valve opening shape under that condition. By adjusting IVF, the intake airflow characteristics can be precisely controlled, making the airflow smoother, reducing turbulence and eddy losses, improving intake efficiency, and avoiding insufficient intake or airflow turbulence caused by improper profile fullness, thereby optimizing the combustion process and reducing fuel consumption. The corresponding comprehensive optimal fuel consumption BSFCmin=fk(IVF) can also be obtained. The comprehensive optimal fuel consumption is a weighted average fuel consumption that takes into account the weights of different road conditions. It reflects the overall economic performance of this combination of intake fullness parameters in actual use scenarios, rather than just performing best under a single condition. It ensures that the engine achieves the best economy under common road conditions, while meeting the requirements of multi-objective optimization. Through weighted calculation, the impact of common conditions on comprehensive fuel consumption is made greater and closer to actual use.

[0050] This yields the universal effective compression ratio and universal intake lift scheme for the vehicle under various road conditions. The universal intake lift scheme is an optimal combination of compression ratio and intake fullness tailored to specific road conditions. It ensures that the engine maintains optimal fuel economy while meeting multiple objectives such as torque, EGR rate, transient response, and knock evaluation. This avoids performance imbalances caused by optimizing a single parameter, achieving comprehensive performance optimization and ensuring the engine achieves the best balance between fuel economy and reliability in various usage scenarios.

[0051] Step 10232: Keeping the initial intake valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing and lift parameters, the optimal exhaust valve fullness matching scheme that meets the minimum overall fuel consumption requirement is obtained by setting different exhaust valve profile fullness parameters. By fixing the intake parameters and specifically optimizing the exhaust valve profile fullness, the impact of valve opening shape on engine performance can be independently evaluated, avoiding mutual interference between intake and exhaust parameters. This makes the optimization process more systematic and precise, ensuring that the best match between exhaust valve fullness and compression ratio is found with limited computational resources. This improves thermal efficiency while optimizing exhaust flow characteristics, reducing exhaust resistance, increasing engine charging efficiency, and effectively reducing fuel consumption.

[0052] By keeping the initial intake valve lift curve constant and optimizing the exhaust fullness, the optimal exhaust timing fk (EVF) can be obtained under different road conditions. Each road condition corresponds to a set of optimal exhaust profile fullness parameters, where EVF is the exhaust valve profile fullness, reflecting the best matching value of the exhaust valve opening shape under that condition. By adjusting EVF, the exhaust airflow characteristics can be precisely controlled, making the airflow smoother, reducing turbulence and eddy losses, improving exhaust efficiency, and avoiding insufficient exhaust or airflow turbulence caused by improper profile fullness. This optimizes the combustion process, reduces fuel consumption, and especially under high load conditions, it can effectively reduce knock tendency and improve engine reliability.

[0053] The corresponding optimal fuel consumption BSFCmin=fk(EVF) is also obtained. The optimal fuel consumption is a weighted average fuel consumption that takes into account the weights of different road conditions. It reflects the overall economic performance of the exhaust fullness parameter combination in actual use scenarios, rather than just the best performance under a single condition. This ensures that the engine achieves the best economy under common road conditions and meets the requirements of multi-objective optimization. By calculating the weights, the impact of common conditions on the overall fuel consumption is made greater and closer to actual use.

[0054] This yields the universal effective compression ratio and universal exhaust lift scheme for the vehicle under various road conditions. The universal exhaust lift scheme is an optimal combination of compression ratio and exhaust volume tailored to specific road conditions. It ensures that the engine maintains optimal fuel economy while meeting multiple objectives such as torque, EGR rate, transient response, and knock evaluation. This avoids performance imbalances caused by optimizing a single parameter, achieving comprehensive performance optimization and ensuring the engine achieves the best balance between fuel economy and reliability in various usage scenarios.

[0055] It should be noted that, based on actual needs and constraints, any of the solutions in steps 10231-10232 can be selected for parameter optimization. The specific solutions implemented depend on real-world constraints such as resources, cost, and the internal layout of the engine. During engine development, different optimization solutions exhibit varying computational complexity and implementation difficulty. Appropriate selection of optimization solutions can effectively balance development efficiency and optimization effectiveness, avoiding resource waste and extended development cycles due to over-optimization, and ensuring that the optimization process is both scientific and practical.

[0056] Step 1024: Based on the geometric compression ratio under different road conditions, combined with the intake and exhaust timing parameters, intake and exhaust valve lift parameters, and intake and exhaust valve profile fullness parameters, obtain the universal effective compression ratio and universal intake and exhaust full-volume parameter matching scheme that meets the minimum requirements for comprehensive fuel consumption. By integrating the results of multi-parameter optimization, a complete parameter matching scheme is formed, ensuring optimal synergy between parameters, avoiding performance degradation of other parameters due to optimization of a single parameter, achieving optimal matching of comprehensive fuel consumption, ensuring that the engine can achieve optimal performance under various road conditions, and simultaneously meeting the multi-objective optimization requirements of torque, EGR rate, transient response, and knock evaluation.

[0057] The global optimization of all factors can simultaneously obtain the optimal timing, lift, and fullness fk (IVO, IVC, EVO, EVC, IVL, EVL, IVF, EVF) under different road conditions. Each road condition corresponds to a set of optimal parameter combinations. Matching these parameters can optimize the engine's intake and exhaust processes, so that the intake volume, exhaust volume, and airflow characteristics are optimally coordinated, reducing airflow interference and energy loss, improving charging efficiency, thereby reducing fuel consumption, and avoiding the decline of other performance indicators caused by optimizing a single parameter.

[0058] The corresponding optimal fuel consumption is obtained as BSFCmin=fk(IVO, IVC, EVO, EVC, IVL, EVL, IVF, EVF). The optimal fuel consumption is a weighted average fuel consumption that takes into account the weights of different road conditions. It reflects the overall economic performance of this combination of parameters in actual use scenarios, rather than being optimal only under a single condition. This ensures that the engine achieves optimal economy under common road conditions while meeting multi-objective optimization requirements. Weight calculations make the impact of common operating conditions on overall fuel consumption greater, more closely reflecting actual usage.

[0059] This yields the universal operating condition effective compression ratio and universal operating condition intake and exhaust full parameter matching scheme that meet the minimum requirements for comprehensive fuel consumption. The universal operating condition intake and exhaust full parameter matching scheme is designed for specific road conditions, combining the optimal matching combination of compression ratio and all-factor parameters to ensure that the engine maintains optimal economy under this condition while meeting multiple objective requirements such as torque, EGR rate, transient response, and knock evaluation. It avoids performance imbalance caused by optimizing a single parameter, achieves optimal comprehensive performance, and ensures that the engine can achieve the best balance between economy and reliability in various usage scenarios.

[0060] Through the aforementioned matching strategy, and through optimization strategies involving partial or full variables, the optimal combined fuel consumption under various common vehicle operating conditions can be obtained, satisfying the development goals and boundary requirements of the gas engine. This corresponds to n sets of optimal results combining compression ratios with intake and exhaust valve timing, lift, and fullness. These results comprehensively consider the weights of different road conditions, engine performance boundary conditions, and actual development constraints, ensuring the practicality and feasibility of the optimization results. Combining design and other factors, n optimal compression ratio + intake and exhaust camshaft schemes that can be prototyped are selected. The selection process considers the mechanical strength, processing difficulty, cost, and compatibility with other engine components of the camshaft, ensuring that the selected schemes meet performance requirements and have high manufacturability. Subsequently, n+1 sets of camshaft schemes, including the base engine scheme, are experimentally verified. The base engine scheme serves as a control group to evaluate the performance improvement effect of the optimized schemes, ensuring the reliability of the optimization results and avoiding development risks caused by a single optimized scheme. Comparative analysis allows for a more accurate evaluation of the actual effects of each parameter combination.

[0061] This screening and verification process ensures a smooth transition from simulation optimization to practical application, enabling the final matching scheme to meet the requirements of gas engines in terms of economy, power, reliability, and emissions, while also being feasible for actual engineering implementation. This effectively avoids increased development costs and extended development cycles caused by over-optimization, achieving the optimal balance between development efficiency and optimization effectiveness.

[0062] Therefore, after obtaining the universal operating condition effective compression ratio and universal operating condition intake and exhaust full-volume parameter matching scheme that meet the minimum requirements for comprehensive fuel consumption under different road conditions, the method also includes: First, at least one candidate scheme is selected from the full range of intake and exhaust parameter matching schemes under universal operating conditions for prototype testing and verification. Each candidate scheme includes different compression ratios and corresponding intake and exhaust camshaft parameter combinations. The selection process takes into account development resources, cost budget and engine internal layout constraints, giving priority to schemes with high matching degree between compression ratio and camshaft parameters and good manufacturing feasibility, to ensure the practicality and operability of the test verification and avoid resource waste and development risks caused by improper selection.

[0063] Then, for each candidate solution, the operating condition is determined to be either idling or non-idling by identifying the engine throttle opening and speed signals. The ECU monitors the engine operating status and classifies the operating conditions to ensure the relevance of subsequent parameter corrections, avoid optimization deviations caused by incorrect operating condition judgments, and improve optimization accuracy.

[0064] Next, under idling conditions, the throttle opening and boost pressure are kept at the set values, and the EGR valve opening and ignition angle are adjusted to obtain the optimal specific air consumption parameters. In this embodiment, the throttle opening is kept at K(0) and the boost pressure at P(0). Under idling conditions, by controlling the EGR valve opening and ignition angle, the engine can achieve the optimal combustion state at low speeds, reducing idling vibration, improving fuel economy, and avoiding engine stalling or unstable operation due to improper parameters. Under non-idling conditions, the throttle opening K(x) and boost pressure P(x) are set for different operating conditions, and the optimal specific air consumption parameters are obtained by adjusting the EGR valve opening and ignition angle. Under non-idling conditions, the parameters are dynamically adjusted according to different load requirements to ensure that the engine maintains the best combustion efficiency under various operating conditions, avoiding performance degradation due to fixed parameters, and improving the overall performance of the engine in actual use.

[0065] Finally, the test data of each candidate scheme under various operating conditions are calibrated and iteratively optimized with the one-dimensional simulation model of the gas engine until the final matching scheme that is consistent with the simulation and test results and satisfies the optimal comprehensive fuel consumption is obtained. By feeding the test results back to the simulation model, a closed loop of "simulation-experiment-feedback-optimization" is formed, making the optimization process more scientific and accurate, avoiding prediction bias caused by relying solely on simulation, and ensuring that the final matching scheme meets both simulation expectations and actual usage requirements.

[0066] The process involves calibrating and iteratively optimizing the experimental data of each candidate scheme under various operating conditions with a one-dimensional simulation model of the gas engine. Specifically, this includes comparing the performance-related parameters obtained from the experiments, including the optimal specific gas consumption, with the predicted data from the simulation model to calculate the relative error of the performance data. When the relative error of all performance data is less than a preset threshold, and the conclusions of the simulation and the optimal scheme are consistent, the combination of compression ratio and intake and exhaust camshaft parameters of the current candidate scheme is taken as the final matching optimization scheme. A relative error less than the preset threshold indicates that the simulation model has a high degree of agreement with the actual experimental results, the optimization scheme is reliable, and it can be directly used for actual production, avoiding resource waste caused by over-optimization. Otherwise, the simulation model parameters are adjusted based on error feedback, and the iteration is repeated until the final matching scheme is obtained. Through iterative optimization, the gap between simulation and reality is gradually narrowed, ensuring the accuracy and reliability of the final matching scheme, avoiding deviations caused by single optimizations, and improving the credibility of the optimization results.

[0067] Specifically: For example, based on the above simulation optimization scheme, experimental verification is carried out. First, the compression ratio CR1 and intake and exhaust camshafts f1 (IVO, IVC, EVO, EVC, IVL, EVL, IVF, EVF) of the prototype scheme 1 are selected to build a prototype for testing. Subsequently, the scheme 2 (compression ratio CR2 and intake and exhaust camshafts f2 (IVO, IVC, EVO, EVC, IVL, EVL, IVF, EVF)), scheme 3 (compression ratio CR3 and intake and exhaust camshafts f3 (IVO, IVC, EVO, EVC, IVL, EVL, IVF, EVF)) are replaced with scheme n (compression ratio CRn and intake and exhaust camshafts fn (IVO, IVC, EVO, EVC, IVL, EVL, IVF, EVF)) for verification. By systematically testing multiple candidate schemes, the impact of different parameter combinations on engine performance can be comprehensively evaluated, ensuring that the final selected scheme has the best overall performance and avoiding the optimization deficiencies that may be caused by testing only a single scheme.

[0068] The above camshaft profile options can be for fixed camshafts, or for VVT, VVL, VVA, etc. Different camshaft types correspond to different engine control strategies. Variable mechanisms such as VVT, VVL, and VVA provide more flexible parameter adjustment space to adapt to different operating conditions, improve overall engine performance, and also consider practical manufacturing feasibility to ensure the successful implementation of optimized solutions.

[0069] Operating condition determination first involves the ECU identifying engine throttle and speed signals to determine the engine's operating condition, ensuring it operates within the vehicle's commonly used road conditions (condition 1). This condition is primarily categorized into idling and non-idling conditions. This condition classification is based on the engine's actual operating characteristics, ensuring the optimization process targets real-world usage scenarios, improving the practicality of the optimization results, and avoiding overall performance degradation caused by optimizing only for specific operating conditions.

[0070] Under idling conditions, with the throttle opening at K(0) and the boost pressure at P(0), experiments are conducted based on the calibration data of the basic prototype. The simulation input data is used for calibration and correction. The optimal specific gas consumption within the performance limits is sought by correcting the EGR valve opening, ignition angle, etc. The EGR valve opening, ignition angle, throttle opening, boost pressure, etc. corresponding to the current scheme are used as outputs to provide to the simulation model for calibration and iteration.

[0071] In non-idle conditions, i.e., all other universal operating conditions other than idling, the same principle applies. Based on the calibration data, experiments are conducted. Different operating conditions correspond to different throttle openings K(x). Under the boost pressure P(x), the optimal specific air consumption within the performance limits is sought by modifying the EGR valve opening, ignition angle, etc., and the result is output to the simulation model for calibration and iteration.

[0072] In summary, the optimal calibration parameters map of prototype 1 under different operating conditions can be obtained, which can guide subsequent optimization schemes and experimental calibrations, obtain the optimal intake and exhaust profile scheme and the corresponding optimal specific gas consumption, and guide the selection of valve train and piston combustion chamber.

[0073] Therefore, this application is not limited to high compression ratio + Miller cycle (EIVC early intake closing and LIVC late intake closing), but rather to the optimization and matching of all parameters of the valve train (IVO intake opening time, IVC intake closing time, EVO exhaust opening time, EVC exhaust closing time, IVL intake lift, EVL exhaust lift, profile fullness IVF and EVF). By expanding the optimization parameters from the traditional intake closing time to eight parameters including intake opening time, intake closing time, exhaust opening time, exhaust closing time, intake lift, exhaust lift and profile fullness, more comprehensive and precise control of the valve train system is achieved. This avoids the performance degradation of other parameters caused by optimizing only a single parameter, enabling the engine to achieve the best matching state under various operating conditions and significantly improving the overall performance of the high compression ratio engine.

[0074] The optimal cam profile for a gas engine under high compression ratios, based on common road conditions for the vehicle, was obtained through simulation analysis. This optimal profile was then output to design and testing as a calibration target. The simulation input was then used for calibration and correction during testing, with the corrected results serving as input for simulation iterations. Finally, through interaction between simulation and testing, the best balance point matching scheme considering all factors was obtained. The simulation calculations were based on statistical analysis of common road conditions for the vehicle, assigning corresponding weights to different road conditions according to their actual usage frequency. Orthogonal combination optimization systematically explored the impact of different parameter combinations on engine performance, ensuring that the optimization results closely approximate real-world usage scenarios. During the experimental verification phase, actual prototype testing was conducted, and the experimental data was fed back to the simulation model, forming a closed loop of "simulation-experiment-feedback-optimization." This made the optimization results more reliable and practical, avoiding prediction biases caused by relying solely on simulation, and ensuring that the final matching scheme exhibits good performance in practical applications.

[0075] The matching method proposed in this application can be used according to the user's actual design situation for (1) high compression ratio + single fixed camshaft, that is, the unique matching camshaft scheme with the best balance point after considering all factors; (2) high compression ratio + VVT, that is, the timing shift scheme based on the unchanged lift of the basic camshaft; (3) high compression ratio + VVL, that is, the lifting scheme based on the unchanged timing of the basic camshaft; (4) high compression ratio + VVA, that is, the timing and lifting can be infinitely adjusted according to MAP. Flexible adaptation schemes are provided for different engine platform hardware conditions and cost budgets: the fixed camshaft scheme is suitable for cost-sensitive products, the VVT ​​scheme is suitable for engines that require a certain degree of flexibility, the VVL scheme is suitable for engines that require adjustment of intake volume, and the VVA scheme provides the highest level of parameter flexibility, which can adjust valve timing and lifting in real time according to engine operating conditions to achieve the best performance matching. The common point of these four schemes is that they are all based on the same parameter optimization basis, which ensures the uniformity and portability of the optimization results.

[0076] This gas turbine engine approach not only considers the improved thermal efficiency and overall fuel economy resulting from a high compression ratio, but also takes into account the impact of the effective compression ratio through full-variable optimization of valve timing, lift, and body shape. This reduces the tendency for engine knocking, improves the reliability of components and the entire engine, and further enhances fuel economy, improves engine thermal efficiency, and reduces emissions through profile optimization. Full-variable optimization not only considers the improved thermal efficiency brought by a high compression ratio, but also effectively adjusts the effective compression ratio by precisely controlling valve timing, lift, and body shape, preventing knocking even at high compression ratios. Optimizing the body shape improves airflow characteristics during valve opening, reduces airflow losses, and further improves engine charging and combustion efficiency. This results in improved thermal efficiency while reducing emissions, achieving multi-objective optimization of fuel economy, reliability, and environmental friendliness, making high-compression ratio engines more widely applicable in practical applications.

[0077] Secondly, this application provides a high compression ratio gas engine matching system, comprising: a first module and a second module. The first module is used to establish a one-dimensional simulation model of the gas engine, using initial intake valve lift curves and initial exhaust valve lift curves as boundary conditions. The second module is used to optimize the total intake and exhaust parameters based on the one-dimensional simulation model of the gas engine and the universal operating conditions of the engine, for different geometric compression ratios, to obtain a universal operating condition effective compression ratio and universal operating condition intake and exhaust parameter matching scheme that meets the minimum comprehensive fuel consumption requirements under different road conditions. A third module is also included, which is used for iterative interaction between experiment and simulation. Based on the optimal matching scheme obtained from the simulation, it is used for experimental verification. The experimental results are further compared with the simulation results for calibration and model optimization. The final matching scheme is not only the optimized scheme output by the simulation but also can be verified experimentally.

[0078] The functions of each module in the high compression ratio gas engine matching system correspond to the steps in the high compression ratio gas engine matching method embodiment, and their functions and implementation processes will not be described in detail here.

[0079] Thirdly, embodiments of this application provide a high compression ratio gas engine matching device, which can be a personal computer (PC), laptop computer, server, or other device with data processing capabilities.

[0080] In this embodiment, the high compression ratio gas engine matching device may include a processor, a memory, a communication interface, and a communication bus.

[0081] The communication bus can be of any type and is used to interconnect the processor, memory, and communication interface.

[0082] The communication interface includes input / output (I / O) interfaces, physical interfaces, and logical interfaces used for interconnecting components within the high-compression-ratio gas engine matching equipment, as well as interfaces used for interconnecting the high-compression-ratio gas engine matching equipment with other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet interfaces, fiber optic interfaces, ATM interfaces, etc.; user equipment can be displays, keyboards, etc.

[0083] Memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0084] The processor can be a general-purpose processor, which can call the high compression ratio gas engine matching program stored in the memory and execute the high compression ratio gas engine matching method provided in the embodiments of this application. For example, the general-purpose processor can be a central processing unit (CPU). The method executed when the high compression ratio gas engine matching program is called can be referred to the various embodiments of the high compression ratio gas engine matching method of this application, and will not be repeated here.

[0085] Fourthly, embodiments of this application also provide a computer-readable storage medium.

[0086] The present application provides a computer-readable storage medium storing a high compression ratio gas engine matching program, wherein when the high compression ratio gas engine matching program is executed by a processor, it implements the steps of the high compression ratio gas engine matching method described above.

[0087] The method implemented when the high compression ratio gas engine matching procedure is executed can be referred to in various embodiments of the high compression ratio gas engine matching method of this application, and will not be repeated here.

[0088] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0089] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0090] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0091] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0092] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0093] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0094] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A matching method for a high compression ratio gas engine, characterized in that, It includes: A one-dimensional simulation model of the gas engine was established, with the initial geometric compression ratio, initial intake valve lift curve, and initial exhaust valve lift curve as boundary conditions. Based on a one-dimensional simulation model of a gas engine and the universal operating conditions of the engine, the intake and exhaust full parameters are optimized for different geometric compression ratios to obtain the universal operating effective compression ratio and universal operating condition intake and exhaust full parameter matching scheme that meet the minimum requirements for comprehensive fuel consumption under different road conditions.

2. The high compression ratio gas engine matching method as described in claim 1, characterized in that, The total intake parameters include intake valve opening time parameters, intake valve closing time parameters, intake valve lift parameters, and intake valve profile fullness parameters; the total exhaust parameters include exhaust valve opening time parameters, exhaust valve closing time parameters, exhaust valve lift parameters, and exhaust valve profile fullness parameters.

3. The high compression ratio gas engine matching method as described in claim 2, characterized in that, Based on a one-dimensional simulation model of a gas engine and its universal operating conditions, this study optimizes the total intake and exhaust parameters for different geometric compression ratios. This yields a universal operating condition effective compression ratio and universal operating condition intake and exhaust parameter matching schemes that meet the minimum combined fuel consumption requirements under various road conditions. Specifically, these include: Based on a one-dimensional simulation model of a gas engine and the universal operating conditions of the engine, the intake and exhaust valve timing parameters are optimized for different geometric compression ratios to obtain the universal operating effective compression ratio, universal operating condition intake and exhaust timing combination parameters, and corresponding geometric compression ratio that meet the minimum requirements for comprehensive fuel consumption. The intake and exhaust valve timing parameters include: intake valve opening time parameters, intake valve closing time parameters, exhaust valve opening time parameters, and exhaust valve closing time parameters. Based on the one-dimensional simulation model of the gas engine and the universal operating conditions of the engine, the corresponding geometric compression ratio and the optimized intake and exhaust valve timing scheme parameters, the intake and exhaust valve profile lift scheme parameters are optimized to obtain the universal operating effective compression ratio and universal operating condition intake and exhaust valve lift combination parameters that meet the minimum requirements of comprehensive fuel consumption. The lift scheme parameters include: intake valve lift parameters and exhaust valve lift parameters. Based on the one-dimensional simulation model of the gas engine and the universal operating conditions of the engine, the corresponding geometric compression ratio, and the optimized intake and exhaust valve timing and lift parameters, the intake valve profile fullness parameters and exhaust valve profile fullness parameters are optimized to obtain the universal operating effective compression ratio and universal operating condition intake and exhaust valve profile fullness combination parameters that meet the minimum requirements for comprehensive fuel consumption. Based on the geometric compression ratio under different road conditions, combined with the intake and exhaust timing parameters, intake and exhaust valve lift parameters, and intake and exhaust valve profile fullness parameters, a universal operating condition effective compression ratio and universal operating condition intake and exhaust full parameter matching scheme that meet the minimum requirements for comprehensive fuel consumption are obtained.

4. The high compression ratio gas engine matching method as described in claim 3, characterized in that, Based on a one-dimensional simulation model of a gas engine and its universal operating conditions, the intake and exhaust valve timing parameters are optimized for different geometric compression ratios to obtain the effective compression ratio, intake and exhaust timing combination parameters, and corresponding geometric compression ratio that meet the minimum overall fuel consumption requirements. The intake and exhaust valve timing parameters include: intake valve opening time parameters, intake valve closing time parameters, exhaust valve opening time parameters, and exhaust valve closing time parameters, specifically including: Keeping the initial exhaust valve lift curve in the one-dimensional simulation model of the gas engine unchanged, for different geometric compression ratios, the optimal intake timing matching scheme that meets the minimum comprehensive fuel consumption requirement is obtained by orthogonally combining different intake valve opening time parameters and different intake valve closing time parameters. Keeping the initial intake valve lift curve in the one-dimensional simulation model of the gas engine unchanged, for different geometric compression ratios, the optimal exhaust timing matching scheme that meets the minimum comprehensive fuel consumption requirement is obtained by orthogonally combining different exhaust valve opening time parameters and different exhaust valve closing time parameters. For different geometric compression ratios, the optimal intake and exhaust timing matching scheme and corresponding geometric compression ratio parameters that meet the minimum overall fuel consumption requirement under universal operating conditions are obtained by orthogonally combining different intake valve opening time parameters, intake valve closing time parameters, exhaust valve opening time parameters, and exhaust valve closing time parameters.

5. The high compression ratio gas engine matching method as described in claim 3, characterized in that, Based on a one-dimensional simulation model of the gas engine and its universal operating conditions, corresponding geometric compression ratio, and optimized intake and exhaust valve timing parameters, the intake and exhaust valve lift parameters are optimized to obtain the universal operating effective compression ratio and universal operating condition intake and exhaust valve lift combination parameters that meet the minimum overall fuel consumption requirements. The lift parameters include intake valve lift parameters and exhaust valve lift parameters, specifically: Keeping the initial exhaust valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing parameters, the optimal intake timing matching scheme that meets the minimum comprehensive fuel consumption requirement under universal operating conditions is obtained by setting different intake valve lift parameters. Keeping the initial intake valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing parameters, the optimal exhaust timing matching scheme that meets the minimum comprehensive fuel consumption requirement under universal operating conditions is obtained by setting different exhaust valve lift parameters. Based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing parameters, the optimal intake and exhaust valve lift matching scheme that meets the minimum overall fuel consumption requirement under universal operating conditions is obtained by orthogonally combining different intake valve lift parameters and different exhaust valve lift parameters.

6. The high compression ratio gas engine matching method as described in claim 3, characterized in that, Based on a one-dimensional simulation model of the gas engine and its universal operating conditions, corresponding geometric compression ratio, and optimized intake and exhaust valve timing and lift parameters, the intake and exhaust valve profile fullness parameters are optimized to obtain the universal operating effective compression ratio and universal operating intake and exhaust valve profile fullness combination parameters that meet the minimum requirements for combined fuel consumption. Specifically, these parameters include: Keeping the initial exhaust valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing and lift parameters, the optimal intake fullness matching scheme for universal operating conditions that meets the minimum requirements of comprehensive fuel consumption is obtained. Keeping the initial intake valve lift curve in the one-dimensional simulation model of the gas engine unchanged, based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing and lift parameters, the optimal exhaust fullness matching scheme that meets the minimum comprehensive fuel consumption requirement under universal operating conditions is obtained by setting different exhaust valve profile fullness parameters.

7. The high compression ratio gas engine matching method as described in claim 1, characterized in that, The universal operating condition effective compression ratio and universal operating condition intake and exhaust full parameter matching scheme for each road condition can achieve optimal overall vehicle fuel consumption while meeting torque target, EGR rate target, transient response target, knock evaluation target and not exceeding the various boundary limits required by the engine.

8. The high compression ratio gas engine matching method as described in claim 1, characterized in that, After obtaining the universal operating condition effective compression ratio and universal operating condition intake and exhaust full-volume parameter matching scheme that meet the minimum comprehensive fuel consumption requirements under different road conditions, the method further includes: At least one candidate scheme is selected from the full parameter matching scheme of intake and exhaust under universal operating conditions for prototype testing and verification. Each candidate scheme includes different compression ratios and corresponding combinations of intake and exhaust camshaft parameters. For each candidate scheme, the operating condition is determined to be either idling or non-idling by identifying the engine throttle opening and speed signals. Under idling conditions, the throttle opening and boost pressure are kept at the set values, and the EGR valve opening and ignition angle are adjusted to obtain the optimal specific air consumption parameters. Under non-idle conditions, the throttle opening and boost pressure are set according to different operating conditions, and the optimal specific air consumption parameters are obtained by modifying the EGR valve opening and ignition angle. The test data of each candidate scheme under various operating conditions are calibrated and iteratively optimized with the one-dimensional simulation model of the gas engine until the final matching scheme that is consistent with the simulation and test results and satisfies the optimal comprehensive fuel consumption is obtained.

9. The high compression ratio gas engine matching method as described in claim 8, characterized in that, The test data of each candidate scheme under various operating conditions are calibrated and iteratively optimized using the one-dimensional simulation model of the gas engine. Specifically, this includes: The performance-related parameters obtained from the experiment, including the optimal specific gas consumption, are compared with the predicted data from the simulation model to calculate the relative error of the performance data. When the relative error of all performance data is less than the preset threshold, and the conclusions of the simulation and the experiment are consistent, the compression ratio and intake and exhaust camshaft parameters of the current candidate scheme are used as the final matching optimization scheme. Otherwise, the simulation model parameters are adjusted based on error feedback, and the iteration is repeated until the final matching solution is obtained.

10. A high compression ratio gas engine matching system, characterized in that, It includes: The first module is used to establish a one-dimensional simulation model of the gas engine, and uses the initial geometric compression ratio, the initial intake valve lift curve and the initial exhaust valve lift curve as boundary conditions. The second module is used to optimize the intake and exhaust full parameters based on the one-dimensional simulation model of the gas engine and the universal operating conditions of the engine, for different geometric compression ratios, to obtain the universal operating condition effective compression ratio and universal operating condition intake and exhaust full parameter matching scheme that meet the minimum requirements of comprehensive fuel consumption under different road conditions.

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