CN-122020985-A - High compression ratio gas engine matching method and system thereof

CN122020985ACN 122020985 ACN122020985 ACN 122020985ACN-122020985-A

Abstract

The application relates to a high compression ratio gas engine matching method and a system thereof, wherein the method comprises the steps of establishing a gas engine one-dimensional simulation model, 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 the universal working condition of the engine, the air intake full-quantity parameter and the air exhaust full-quantity parameter are optimized according to different geometric compression ratios, and the universal working condition effective compression ratio and the universal working condition air intake and exhaust full-quantity parameter matching scheme meeting the minimum comprehensive oil consumption requirements under different road working conditions are obtained. The application determines the parameter setting scheme which is most suitable for the geometric compression ratio of the engine and the molded line of the air intake and exhaust cam, realizes the cooperative optimization of the compression ratio and the full parameter aiming at the working condition of the common road of the whole vehicle, ensures that the gas engine not only can realize the heat efficiency improvement of low rotation speed through high compression ratio, but also can realize the design matching of high compression ratio and low actual load through Miller cycle, and ensures that the engine is superior to a simple high compression ratio model.

Inventors

MI JIAO
ZHAO YANTING
LU DING
LIU BEI
WANG XIN

Assignees

东风汽车集团股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260106

Claims (10)

1. A high compression ratio gas engine matching method, characterized in that it comprises: Establishing a one-dimensional simulation model of the 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 the universal working condition of the engine, the air intake full-quantity parameter and the air exhaust full-quantity parameter are optimized according to different geometric compression ratios, and the universal working condition effective compression ratio and the universal working condition air intake and exhaust full-quantity parameter matching scheme meeting the minimum comprehensive oil consumption requirements under different road working conditions are obtained.
2. The method for matching a high compression ratio gas engine as defined in claim 1, wherein the intake air total parameter comprises an intake valve opening time parameter, an intake valve closing time parameter, an intake valve lift parameter and an intake valve profile fullness parameter, and the exhaust air total parameter comprises an exhaust valve opening time parameter, an exhaust valve closing time parameter, an exhaust valve lift parameter and an exhaust valve profile fullness parameter.
3. The high compression ratio gas engine matching method as set forth in claim 2, wherein the gas engine matching method is characterized in that based on a one-dimensional simulation model of the gas engine and the universal working condition of the engine, the intake full parameter and the exhaust full parameter are optimized for setting different geometric compression ratios, and the universal working condition effective compression ratio and the universal working condition intake and exhaust full parameter matching scheme meeting the minimum comprehensive fuel consumption requirements under different road working conditions are obtained, and specifically comprises: Based on a one-dimensional simulation model of the gas engine and universal working conditions of the engine, optimizing timing scheme parameters of an intake valve and an exhaust valve according to different geometric compression ratios to obtain universal working condition effective compression ratio, universal working condition intake and exhaust timing combination parameters and corresponding geometric compression ratio which meet the minimum requirement of comprehensive oil consumption, wherein the timing scheme parameters of the intake valve and the exhaust valve comprise intake valve opening time parameters, intake valve closing time parameters, exhaust valve opening time parameters and exhaust valve closing time parameters; Based on a one-dimensional simulation model of a gas engine, a universal working condition of the engine, a corresponding geometric compression ratio and an optimized intake and exhaust valve timing scheme parameter, optimizing an intake and exhaust valve molded line lift scheme parameter, and obtaining a universal working condition effective compression ratio and a universal working condition intake and exhaust valve lift combination parameter meeting the minimum requirement of comprehensive oil consumption, wherein the lift scheme parameter comprises an intake valve lift parameter and an exhaust valve lift parameter; Based on a one-dimensional simulation model of the gas engine, the universal working condition of the engine, the corresponding geometric compression ratio, and the optimized intake and exhaust valve timing scheme parameter and lift scheme parameter, optimizing the intake valve molded line fullness parameter and the exhaust valve molded line fullness parameter to obtain the universal working condition effective compression ratio and the universal working condition intake and exhaust valve molded line fullness combination parameter which meet the minimum requirement of comprehensive oil consumption; based on the geometric compression ratio matched with the intake and exhaust timing combination parameters, the intake and exhaust valve lift combination parameters and the intake and exhaust valve molded line fullness combination parameters under different road working conditions, the universal working condition effective compression ratio and universal working condition intake and exhaust full parameter matching scheme meeting the minimum requirement of comprehensive oil consumption is obtained.
4. The high compression ratio gas engine matching method as set forth in claim 3, wherein based on a one-dimensional simulation model of the gas engine and a universal working condition of the engine, for setting different geometric compression ratios, optimizing timing scheme parameters of an intake valve and an exhaust valve to obtain a universal working condition effective compression ratio, a universal working condition intake and exhaust timing combination parameter and a corresponding geometric compression ratio which meet the minimum requirement of comprehensive fuel consumption, wherein the timing scheme parameters of the intake valve and the exhaust valve comprise an intake valve opening time parameter, an intake valve closing time parameter, an exhaust valve opening time parameter and an exhaust valve closing time parameter, and specifically comprise: Keeping the lift curve of the initial exhaust valve in the one-dimensional simulation model of the gas engine unchanged, and aiming at setting different geometric compression ratios, carrying out orthogonal combination by setting different intake valve opening time parameters and different intake valve closing time parameters to obtain an optimal intake timing matching scheme with ten thousand working conditions, wherein the optimal intake timing matching scheme meets the minimum requirement of comprehensive oil consumption; Keeping the lift curve of an initial intake valve in a one-dimensional simulation model of the gas engine unchanged, and aiming at setting different geometric compression ratios, carrying out orthogonal combination by setting different exhaust valve opening time parameters and different exhaust valve closing time parameters to obtain an optimal exhaust timing matching scheme with ten thousand working conditions, wherein the optimal exhaust timing matching scheme meets the minimum requirement of comprehensive oil consumption; And setting different geometric compression ratios, and carrying out orthogonal combination by setting different intake valve opening time parameters, intake valve closing time parameters, exhaust valve opening time parameters and exhaust valve closing time parameters to obtain an optimal intake and exhaust timing matching scheme and corresponding geometric compression ratio parameters of all working conditions meeting the minimum requirement of comprehensive oil consumption.
5. The method for matching a high compression ratio gas engine as claimed in claim 3, wherein the lift scheme parameters of the gas engine are optimized based on a one-dimensional simulation model of the gas engine, a universal working condition of the engine, a corresponding geometric compression ratio and optimized timing scheme parameters of the gas inlet and outlet valves, and the lift scheme parameters comprise the effective compression ratio of the universal working condition and the lift combination parameters of the gas inlet and outlet valves meeting the minimum requirement of comprehensive oil consumption, and the lift scheme parameters comprise the lift parameters of the gas inlet valves and the lift parameters of the gas outlet valves, and specifically comprise: The method comprises the steps of keeping an initial exhaust valve lift curve in a one-dimensional simulation model of the gas engine unchanged, and obtaining an optimal intake timing matching scheme of a universal working condition meeting the minimum requirement of comprehensive oil consumption by setting different intake valve lift parameters based on corresponding geometric compression ratio and optimized intake and exhaust valve timing scheme parameters; Keeping an initial intake valve lift curve in a one-dimensional simulation model of the gas engine unchanged, and obtaining an optimal exhaust timing matching scheme of a universal working condition meeting the minimum requirement of comprehensive oil consumption by setting different exhaust valve lift parameters based on corresponding geometric compression ratio and optimized intake and exhaust valve timing scheme parameters; Based on the corresponding geometric compression ratio and optimized intake and exhaust valve timing scheme parameters, the optimal intake and exhaust valve lift matching scheme meeting the comprehensive fuel consumption minimum requirement under the universal working conditions is obtained by setting different intake valve lift parameters and different exhaust valve lift parameters for orthogonal combination.
6. The high compression ratio gas engine matching method as set forth in claim 3, wherein the optimization of the intake valve profile fullness parameter and the exhaust valve profile fullness parameter based on the gas engine one-dimensional simulation model and the engine universal working condition, the corresponding geometric compression ratio and the optimized intake and exhaust valve timing scheme parameter and lift scheme parameter, the obtaining of the combination of the universal working condition effective compression ratio and the universal working condition intake and exhaust valve profile fullness parameter meeting the minimum requirement of the comprehensive fuel consumption, specifically comprises: Keeping an initial exhaust valve lift curve in a one-dimensional simulation model of the gas engine unchanged, and obtaining an optimal intake fullness matching scheme of a universal working condition meeting the minimum requirement of comprehensive oil consumption based on a corresponding geometric compression ratio and optimized intake and exhaust valve timing scheme parameters and lift scheme parameters; And (3) keeping the lift curve of the initial intake valve in the one-dimensional simulation model of the gas engine unchanged, and obtaining an optimal exhaust fullness matching scheme of various working conditions meeting the minimum requirement of comprehensive oil consumption by setting different exhaust valve molded line fullness parameters based on corresponding geometric compression ratio and optimized intake and exhaust valve timing scheme parameters and lift scheme parameters.
7. The high compression ratio gas engine matching method according to claim 1, wherein the matching scheme of the corresponding universal working condition effective compression ratio and universal working condition total intake and exhaust parameters under each road working condition can realize the overall fuel consumption optimization of the whole vehicle while meeting a torque target, an EGR rate target, a transient response target and a knock evaluation target and not exceeding various boundary limit values required by an engine.
8. The method for matching a high compression ratio gas engine according to claim 1, wherein after obtaining a universal working condition effective compression ratio and universal working condition intake and exhaust total parameter matching scheme meeting the minimum requirement of comprehensive oil consumption under different road working conditions, the method further comprises: at least one candidate scheme is selected from all-purpose working condition intake and exhaust total parameter matching schemes to carry out prototype test verification, and each candidate scheme comprises different compression ratios and corresponding intake and exhaust camshaft parameter combinations; for each candidate scheme, judging the operation condition to be an idle condition or a non-idle condition by identifying the opening degree of an engine accelerator and a rotating speed signal; Under the idle working condition, maintaining the opening of a throttle valve as a set value and the boost pressure as a set value, and correcting the opening of an EGR valve and the ignition angle to obtain an optimal specific gas consumption parameter; Under the non-idle working condition, setting the opening degree and the supercharging pressure of a throttle valve aiming at different working conditions, and obtaining the optimal specific gas consumption parameter by correcting the opening degree and the ignition angle of an EGR valve; And (3) calibrating and iteratively optimizing the test data of each candidate scheme under each working condition and the one-dimensional simulation model of the gas engine until a final matching scheme which is consistent in simulation and test results and meets the optimal comprehensive fuel consumption is obtained.
9. The high compression ratio gas engine matching method as set forth in claim 8, wherein the calibration and iterative optimization of the test data of each candidate scheme under each working condition and the gas engine one-dimensional simulation model specifically includes: comparing the performance related parameters including the optimal specific gas consumption obtained by the test with the prediction data of the simulation model, and calculating the relative error of the performance data; when the relative errors of all the performance data are smaller than a preset threshold value and the simulation is consistent with the conclusion of the optimal experimental scheme, combining the compression ratio of the current candidate scheme and the parameters of the intake camshaft and the exhaust camshaft as a final matching optimal scheme; otherwise, adjusting simulation model parameters based on error feedback, and repeating iteration until a final matching scheme is obtained.
10. A high compression ratio gas engine matching system, comprising: The first module is used for establishing a one-dimensional simulation model of the gas engine and takes an initial geometric compression ratio, an initial intake valve lift curve and an initial exhaust valve lift curve as boundary conditions; The second module is used for optimizing the total intake parameter and the total exhaust parameter according to different geometric compression ratios based on the one-dimensional simulation model of the gas engine and the universal working condition of the engine, and obtaining the universal working condition effective compression ratio and the universal working condition total intake and exhaust parameter matching scheme meeting the minimum comprehensive oil consumption requirements under different road working conditions.

Description

High compression ratio gas engine matching method and system thereof Technical Field The application relates to the field of engines, in particular to a high compression ratio gas engine matching method and a system thereof. Background In order to cope with the global common pursuit of carbon reduction, energy saving and environmental protection, the improvement of the thermal efficiency of an engine has been an important subject. From the thermodynamic principle, having a high compression ratio brings about a higher thermal efficiency, since the gas is compressed more fully during the compression process, the heat released during combustion can be converted more effectively into mechanical work, reducing the energy waste, and therefore an increase in the compression ratio will increase the efficiency of the constant volume heating cycle (otto cycle) of the engine. The high compression ratio can also bring about the improvement of dynamic property, the high compression ratio can enable the mixed gas in the cylinder to generate higher explosion pressure when in combustion, the force for pushing the piston to do work is larger, the torque and the power output of the engine are further improved, and particularly under the low-speed working condition, the high compression ratio can reduce pumping loss, so that the dynamic response is more direct. However, the high compression ratio also causes the mechanical load and the thermal load of the engine to increase, and the most direct reaction is that knocking is stronger at the high compression ratio, and the greater the compression ratio is, the more obvious the knocking trend is. In addition, the high compression ratio can lead to the pressure and temperature of the cylinder to be obviously increased at the end of compression, and the core components of the engine such as a piston, a connecting rod, a cylinder body, a valve and the like need to bear larger mechanical stress and thermal shock, so that the risks of abrasion, deformation and even fracture of the components are increased, the service life of the engine is shortened, and the reliability is reduced. Disclosure of Invention The application provides a high-compression ratio gas engine matching method and a system thereof, which can solve the problems of power performance reduction and engine thermal efficiency reduction caused by easy knocking of a gas engine under high compression ratio in the prior art. In a first aspect, an embodiment of the present application provides a method for matching a high compression ratio gas engine, including: Establishing a one-dimensional simulation model of the gas engine, and taking 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 the universal working condition of the engine, the air intake full-quantity parameter and the air exhaust full-quantity parameter are optimized according to different geometric compression ratios, and the universal working condition effective compression ratio and the universal working condition air intake and exhaust full-quantity parameter matching scheme meeting the minimum comprehensive oil consumption requirements under different road working conditions are obtained. With reference to the first aspect, in one implementation, the intake air total parameter includes an intake valve opening time parameter, an intake valve closing time parameter, an intake valve lift parameter and an intake valve profile fullness parameter, and the exhaust air total parameter includes an exhaust valve opening time parameter, an exhaust valve closing time parameter, an exhaust valve lift parameter and an exhaust valve profile fullness parameter. With reference to the first aspect, in one embodiment, based on the one-dimensional simulation model of the gas engine and the universal working condition of the engine, the intake full-quantity parameter and the exhaust full-quantity parameter are optimized according to different geometric compression ratios, so as to obtain the universal working condition effective compression ratio and the universal working condition intake and exhaust full-quantity parameter matching scheme meeting the minimum requirement of comprehensive fuel consumption under different road working conditions, specifically including: Based on a one-dimensional simulation model of the gas engine and universal working conditions of the engine, optimizing timing scheme parameters of an intake valve and an exhaust valve according to different geometric compression ratios to obtain universal working condition effective compression ratio, universal working condition intake and exhaust timing combination parameters and corresponding geometric compression ratio which meet the minimum requirement of comprehensive oil consumption, wherein the timing scheme parameters of the intake valve and the exhaust valve comprise intake valve opening tim