METHOD AND SYSTEM FOR FUEL MANAGEMENT FOR A HIGH-POWER, LARGE-BORE GAS ENGINE

Abstract

A fuel control method for a large-bore high-power gas engine, relating to the field of gas engine control. The method comprises: setting an exhaust gas temperature target value and a cylinder temperature limit value; acquiring a real-time exhaust gas temperature value, and, on the basis of the real-time exhaust gas temperature value and the exhaust gas temperature target value, calibrating a target opening degree of a gas solenoid valve; acquiring a real-time cylinder temperature value, and, on the basis of the real-time cylinder temperature value and the cylinder temperature limit value, determining whether to correct the gas solenoid valve; and when the real-time cylinder temperature value is greater than the cylinder temperature limit value, acquiring a correction coefficient for the opening degree of the gas solenoid valve on the basis of an analysis result of the ratio of the real-time cylinder temperature value to the cylinder temperature limit value. By means of adjusting the opening degree of the gas solenoid valve, the present method corrects abnormal real-time exhaust gas temperature values and real-time cylinder temperature values, thereby solving the problem of unreliability of oxygen sensors, and achieving safe and long-term reliable operation of large-bore high-power gas engines.

Description

Fuel control method and system of large-bore high-power gas engine TECHNICAL FIELD

[0001] The present application relates to the field of gas engine control, and more particularly, to a fuel control method and system of large-bore high-power gas engine. BACKGROUND

[0002] With the improvement of environmental awareness, the market demand for large-bore high-power gas engines is increasing. Large-bore high-power gas engines are used as common engines, and are continuously operated for more than 8000 hours a year except for necessary maintenance time. Long-time operation also reduces the safety during use.

[0003] The current mainstream gas engine usually uses the Lambda signal of the oxygen sensor installed in the exhaust gas turbine of the engine as the fuel closed-loop signal. The advantages of using this fuel closed-loop signal are fast response speed, low cost and low technical difficulty, but the disadvantages are that the service life of the oxygen sensor is limited, the installation position of the oxygen sensor is required to be high, the application range is narrow, and the oxygen sensor is easily affected by impurities such as sulfides in the exhaust gas, thereby affecting the normal use of the oxygen sensor. The use of the oxygen sensor on the industrial large-bore high-power gas engine has limitations, and the oxygen sensor may be poisoned or the signal may be offset after long use, which may cause the gas engine to knock, and finally affect the safe and reliable operation of the gas engine.

[0004] SUMMARY

[0005] The technical problem to be solved by the present application is to solve the technical problem of the unreliability of the existing oxygen sensor in a complex environment.

[0006] The fuel control method of the large-bore high-power gas engine comprises the following steps: setting a target exhaust temperature value and a cylinder temperature limit value;

[0007] Collecting a real-time exhaust temperature value, and calibrating a target opening degree of a gas solenoid valve according to the real-time exhaust temperature value and the target exhaust temperature value;

[0008] Collecting a real-time cylinder temperature value, and determining whether to correct the gas solenoid valve according to the real-time cylinder temperature value and the cylinder temperature limit value; when the real-time cylinder temperature value is greater than the cylinder temperature limit value, a correction coefficient of the opening degree of the gas solenoid valve is obtained according to the analysis result between the real-time cylinder temperature value and the cylinder temperature limit value;

[0009] The final opening degree of the gas solenoid valve is obtained according to the target opening degree of the gas solenoid valve and the correction coefficient.

[0010] Further improvement, the method for calibrating the gas target opening degree is:

[0011] The exhaust temperature difference value is obtained by subtracting the real-time exhaust temperature value from the exhaust temperature target value, and the target opening degree corresponding to the exhaust temperature difference value is obtained by querying the load target exhaust temperature curve.

[0012] Further, the real-time exhaust temperature value is closed-loop controlled by the first temperature regulator, so that the real-time exhaust temperature value is the target exhaust temperature value.

[0013] Further, the real-time cylinder temperature value is closed-loop controlled by the second temperature regulator, so that the real-time cylinder temperature value is less than or equal to the cylinder temperature limit value.

[0014] A fuel control system of a large-bore high-power gas engine, comprising,

[0015] An exhaust temperature sensor is installed in the exhaust passage of the engine combustion chamber for collecting real-time exhaust temperature signals;

[0016] A cylinder temperature sensor is installed in the intake passage of the engine combustion chamber for collecting real-time cylinder temperature signals;

[0017] A gas solenoid valve is installed at the connection between the gas pipeline and the intake passage of the engine combustion chamber for controlling the entry and exit of gas;

[0018] A controller is used to control the opening degree of the gas solenoid valve according to the real-time exhaust temperature signal and the real-time cylinder temperature signal by using the above-mentioned control method.

[0019] Further improvement, the controller is electrically connected with the cylinder temperature sensor and the exhaust temperature sensor through a temperature signal acquisition module.

[0020] Further, the controller is a PLC. Advantages

[0021] The advantages of the present application are:

[0022] The present application sets the exhaust temperature target value and the cylinder temperature limit value, collects the real-time exhaust temperature value and the real-time cylinder temperature value, compares the real-time exhaust temperature value with the exhaust temperature target value, compares the real-time cylinder temperature value with the cylinder temperature limit value, obtains the corresponding gas regulating valve target opening degree when the real-time exhaust temperature value is abnormal, obtains the correction coefficient when the real-time cylinder temperature value is abnormal, and corrects the target opening degree and the correction coefficient to the gas regulating valve, thereby controlling the fuel / air mixture ratio, solving the problem of unreliable oxygen sensor in complex exhaust environment, and realizing safe and reliable long-time operation of large-bore high-power gas engine. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 is a flow diagram of the fuel control method of the present application;

[0024] Figure 2 is a schematic diagram of the fuel control system of the present application.

[0025] Wherein: 1-controller, 2-temperature signal acquisition module, 3-gas solenoid valve, 4-cylinder temperature sensor, 5-exhaust temperature sensor. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with examples, but does not constitute any limitation to the present application, any limited number of modifications made by anyone within the scope of the claims of the present application is still within the scope of the claims of the present application.

[0027] Referring to Figures 1-2, the present application is a fuel control method for a large-bore high-power gas engine, which sets an exhaust temperature target value and a cylinder temperature limit value.

[0028] The real-time exhaust temperature value is collected, and the target opening of the gas solenoid valve is calibrated according to the real-time exhaust temperature value and the exhaust temperature target value.

[0029] The method for calibrating the gas target opening is to obtain the exhaust temperature difference value by subtracting the real-time exhaust temperature value from the exhaust temperature target value, and to obtain the target opening corresponding to the exhaust temperature difference value by querying the load target exhaust temperature curve.

[0030] The real-time cylinder temperature value is collected, and it is judged whether to correct the gas solenoid valve according to the real-time cylinder temperature value and the cylinder temperature limit value. When the real-time cylinder temperature value is greater than the cylinder temperature limit value, the correction coefficient of the opening of the gas solenoid valve is obtained according to the analysis result between the real-time cylinder temperature value and the cylinder temperature limit value.

[0031] The expression for obtaining the correction coefficient is:

[0032] Wherein, k2 is the correction coefficient, t3 is the real-time cylinder temperature value, and t2 is the cylinder temperature limit value.

[0033] The target correction is performed by combining the correction coefficient and the target opening corresponding to the exhaust temperature difference value, and the opening of the gas solenoid valve is adjusted by the target correction, so that the real-time exhaust temperature value is equal to the exhaust temperature target value and the real-time cylinder temperature value is less than or equal to the cylinder temperature limit value.

[0034] The final opening of the gas solenoid valve is obtained according to the target opening of the gas solenoid valve and the correction coefficient, and the expression for obtaining the final opening of the gas solenoid valve is:

[0035] I2=I1+I0×(1+k2);

[0036] Wherein, k2 is the correction coefficient, I2 is the valve opening to be adjusted, I0 is the initial valve opening, and I1 is the target opening corresponding to the exhaust temperature difference value.

[0037] A fuel control system of a large-bore high-power gas engine, comprising,

[0038] An exhaust temperature sensor 5 is installed in the exhaust passage of the engine combustion chamber for collecting real-time exhaust temperature signals;

[0039] A cylinder temperature sensor 4 is installed in the intake passage of the engine combustion chamber for collecting real-time cylinder temperature signals;

[0040] A gas solenoid valve 3 is installed at the connection between the gas pipeline and the intake passage of the engine combustion chamber for controlling the inflow and outflow of gas;

[0041] A controller 1 is used to control the opening degree of the gas solenoid valve 3 according to the real-time exhaust temperature signals and real-time cylinder temperature signals by using the above-mentioned control method. The controller 1 is electrically connected with the cylinder temperature sensor 4 and the exhaust temperature sensor 5 through a temperature signal acquisition module. The controller 1 is a PLC.

[0042] This embodiment is based on a multi-point manifold injection gas engine. When the engine is at a certain load, the exhaust temperature signals collected by the exhaust temperature sensor 5 and the cylinder temperature signals collected by the cylinder temperature sensor 4 are converted by the temperature signal acquisition module 2 and input to the controller 1 in the engine control cabinet. The controller 1 uses the collected exhaust temperature signals and cylinder temperature signals as closed-loop control signals.

[0043] Taking the exhaust temperature and cylinder temperature control of a certain cylinder in a multi-cylinder engine as an example, the exhaust temperature of all cylinders corresponding to the load target of the engine at a certain load is obtained. The real-time exhaust temperature value is used as the main closed-loop signal, and the real-time cylinder temperature value is used as the correction closed-loop signal to correct the opening flow of the gas solenoid valve 3, thereby affecting the air-fuel ratio in the engine combustion chamber and controlling the exhaust temperature and cylinder temperature. When the real-time cylinder temperature value is greater than the cylinder temperature limit value, the flow of the gas solenoid valve 3 is reduced and corrected. When the real-time cylinder temperature value is less than the cylinder temperature limit value, no secondary correction is performed, so as to control the real-time exhaust temperature value and real-time cylinder temperature value within the target value range.

[0044] The above-mentioned is only the preferred embodiment of the present application. It should be noted that for those skilled in the art, without departing from the structure of the present application, several modifications and improvements can be made, which will not affect the effect and practicality of the patent.

Claims

1. A fuel control method for a high-power, large-bore gas engine, characterized in that the method includes the steps of: setting a target exhaust gas temperature and a limit cylinder temperature; collecting the current exhaust gas temperature value and determining the target opening degree of the gas solenoid valve based on the current exhaust gas temperature value and the target exhaust gas temperature value; collecting the current cylinder temperature value and estimating the need for adjustment of the gas electromagnetic valve based on the current cylinder temperature value and the cylinder temperature limit value; when the current cylinder temperature value exceeds the cylinder temperature limit value, determining the correction coefficient of the opening degree of the gas electromagnetic valve based on the result of analyzing the relationship between the current cylinder temperature value and the cylinder temperature limit value; Based on the target opening degree of the gas electromagnetic valve and the correction coefficient, the final opening degree of the gas electromagnetic valve is determined.

2. A fuel control method for a high-power, large-bore gas engine according to claim 1, wherein the method for determining a target opening degree of a gas valve comprises the steps of: calculating a difference between a current exhaust gas temperature value and a target exhaust gas temperature value to obtain an exhaust gas temperature difference; and determining a target opening degree corresponding to the exhaust gas temperature difference by interrogating a curve of the target exhaust gas temperature versus load.

3. A method for controlling fuel for a high-power gas engine with a large cylinder diameter according to claim 2, characterized in that, in relation to the current value of the exhaust gas temperature, control is carried out in a closed loop using a first temperature controller, ensuring that the current value of the exhaust gas temperature is maintained at the level of the target value of the exhaust gas temperature.

4. A method for controlling fuel for a high-power gas engine with a large cylinder diameter according to claim 1, characterized in that, in relation to the current value of the cylinder temperature, control is carried out in a closed loop using a second temperature controller, ensuring that the current value of the cylinder temperature is maintained less than or equal to the limit value of the cylinder temperature.

5. A fuel management system for a high-power, large-bore gas engine, characterized in that it comprises: an exhaust gas temperature sensor installed in the exhaust channel of the engine combustion chamber and designed to collect signals of the current exhaust gas temperature; a cylinder temperature sensor installed in the intake channel of the engine combustion chamber and designed to collect signals of the current cylinder temperature; a gas electromagnetic valve installed at the junction of the gas pipeline and the inlet channel of the engine combustion chamber and designed to control the intake and outlet of gas; a controller that regulates the degree of opening of the gas electromagnetic valve using the control method according to paragraphs 1-4 based on signals of the current exhaust gas temperature and signals of the current cylinder temperature.

6. A fuel management system for a high-power, large-bore gas engine according to claim 5, wherein the controller is electrically connected to the cylinder temperature sensor and the exhaust gas temperature sensor via a temperature signal collection module.

7. A fuel management system for a high-power, large-bore gas engine according to claim 5, wherein the controller is a PLC.