Fuel control method and system for large-cylinder high-power gas engine

Abstract

The present invention discloses a fuel control method for a large-cylinder, high-power gas engine. This method relates to the field of gas engine control and addresses the technical issue of existing oxygen sensors being unreliable in complex environments. The method comprises setting an exhaust temperature target value and a cylinder temperature limit value; collecting real-time exhaust temperature values ​​and calibrating a target opening of a gas solenoid valve based on the real-time exhaust temperature value and the exhaust temperature target value; collecting real-time cylinder temperature values ​​and determining whether to correct the gas solenoid valve based on the real-time cylinder temperature value and the cylinder temperature limit value. When the real-time cylinder temperature value exceeds the cylinder temperature limit value, a correction coefficient for the gas solenoid valve opening is obtained based on an analysis result of the ratio between the real-time cylinder temperature value and the cylinder temperature limit value. The present invention corrects abnormal real-time exhaust temperature and real-time cylinder temperature values ​​by adjusting the opening of the gas solenoid valve, thereby addressing the issue of unreliable oxygen sensors and ensuring safe, long-term, and reliable operation of large-cylinder, high-power gas engines.

Description

Technical Field

[0001] The present invention relates to the field of gas engine control, and more particularly to a fuel control method and system for a large-cylinder high-power gas engine. Background Art

[0002] With the improvement of environmental awareness, the market demand for large-cylinder, high-power gas engines is increasing. Large-cylinder, high-power gas engines are used as common engines and are in continuous operation except for necessary maintenance time, running for more than 8,000 hours a year. Long-term operation will also reduce safety during use.

[0003] Current mainstream gas engines typically use the lambda signal from an oxygen sensor connected to the exhaust vortex in the combustion engine as a closed-loop fuel signal. The advantages of this closed-loop fuel signal are fast response, low cost, and low technical difficulty. However, the disadvantages are the limited service life of the oxygen sensor, high requirements for its installation location, a narrow range of applications, and the sensor's susceptibility to impurities in the exhaust, such as sulfides, which can affect its normal operation. Oxygen sensors have limitations in industrial-grade, large-bore, high-power gas engines. Over time, oxygen sensors can become poisoned or experience signal offset, potentially causing detonation in the gas engine and ultimately impacting its safe and reliable operation. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the deficiencies of the existing technology and provide a fuel control method for a large-cylinder high-power gas engine, thereby solving the technical problem that the existing oxygen sensor is unreliable in complex environments.

[0005] The present invention provides a fuel control method for a large-cylinder high-power gas engine, which includes setting an exhaust temperature target value and a cylinder temperature limit value;

[0006] Collecting a real-time exhaust temperature value, and calibrating a target opening of the gas solenoid valve according to the real-time exhaust temperature value and the exhaust temperature target value;

[0007] collecting a real-time cylinder temperature value, and determining whether to correct the gas solenoid valve based on the real-time cylinder temperature value and a cylinder temperature limit value; when the real-time cylinder temperature value is greater than the cylinder temperature limit value, obtaining a correction coefficient for the opening of the gas solenoid valve based on a ratio analysis result between the real-time cylinder temperature value and the cylinder temperature limit value;

[0008] The final opening of the gas solenoid valve is obtained according to the target opening of the gas solenoid valve and the correction coefficient.

[0009] As a further improvement, the method for calibrating the target gas opening is:

[0010] An exhaust temperature difference is obtained by subtracting the real-time exhaust temperature value from the exhaust temperature target value, and a target opening corresponding to the exhaust temperature difference is obtained by querying a load target exhaust temperature curve.

[0011] Furthermore, 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.

[0012] Furthermore, 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.

[0013] A fuel control system for a large-cylinder high-power gas engine, comprising:

[0014] The exhaust temperature sensor is installed in the exhaust duct of the engine combustion chamber to collect real-time exhaust temperature signals;

[0015] A cylinder temperature sensor is installed in the intake duct of the engine combustion chamber and is used to collect real-time cylinder temperature signals;

[0016] A gas solenoid valve is installed at the connection between the gas pipeline and the air inlet of the engine combustion chamber to control the inlet and outlet of the gas;

[0017] The controller applies the above control method to control the opening of the gas solenoid valve according to the real-time exhaust temperature signal and the real-time cylinder temperature signal.

[0018] As a further improvement, the controller is electrically connected to the cylinder temperature sensor and the exhaust temperature sensor respectively through the temperature signal acquisition module.

[0019] Furthermore, the controller is a PLC.

[0020] Beneficial effects

[0021] The advantages of the present invention are:

[0022] The present invention sets an exhaust temperature target value and a cylinder temperature limit value, collects real-time exhaust temperature values ​​and real-time cylinder temperature values, compares the real-time exhaust temperature value with the exhaust temperature target value, and compares the real-time cylinder temperature value with the cylinder temperature limit value. When the real-time exhaust temperature value is abnormal, the corresponding target opening of the gas regulating valve is obtained; when the real-time cylinder temperature value is abnormal, the correction coefficient is obtained, and the gas regulating valve is corrected according to the target opening and the correction coefficient, thereby controlling the fuel / air mixture ratio, solving the problem of unreliable oxygen sensors in complex exhaust gas environments, and realizing safe, long-term and reliable operation of large-cylinder high-power gas engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic flow chart of the fuel control method of the present invention;

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

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

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

[0027] See Figure 1-Figure 2 The present invention provides a fuel control method for a large-cylinder high-power gas engine, which sets an exhaust temperature target value and a cylinder temperature limit value.

[0028] Collect the real-time exhaust temperature value and calibrate the target opening of the gas solenoid valve based on the real-time exhaust temperature value and the exhaust temperature target value.

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

[0030] The real-time cylinder temperature value is collected, and whether the gas solenoid valve should be corrected is determined based on 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 for the opening of the gas solenoid valve is obtained based on the ratio 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]

[0033] Among them, k2 is the correction coefficient, t3 is the real-time cylinder temperature value, and t2 is the cylinder temperature limit value.

[0034] The target correction is performed based on the correction coefficient and the target opening corresponding to the exhaust temperature difference. The opening of the gas solenoid valve is adjusted through 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.

[0035] The final opening of the gas solenoid valve is obtained according to the target opening of the gas solenoid valve and the correction coefficient. The expression for obtaining the final opening of the gas solenoid valve is:

[0036] I2=I1+I0×(1+k2);

[0037] Among them, 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.

[0038] A fuel control system for a large-cylinder high-power gas engine, comprising:

[0039] The exhaust temperature sensor 5 is installed in the exhaust duct of the engine combustion chamber and is used to collect real-time exhaust temperature signals;

[0040] Cylinder temperature sensor 4, installed in the intake duct of the engine combustion chamber, used to collect real-time cylinder temperature signals;

[0041] The gas solenoid valve 3 is installed at the connection between the gas pipeline and the air inlet of the engine combustion chamber to control the inlet and outlet of the gas;

[0042] Controller 1 uses the aforementioned control method to control the opening of gas solenoid valve 3 based on the real-time exhaust temperature signal and the real-time cylinder temperature signal. Controller 1 is electrically connected to cylinder temperature sensor 4 and exhaust temperature sensor 5 via a temperature signal acquisition module. Controller 1 is a PLC.

[0043] This embodiment is a gas engine based on multi-point manifold injection. When the gas engine is under a certain load, the exhaust temperature signal collected by the exhaust temperature sensor 5 and the cylinder temperature signal collected by the cylinder temperature sensor 4 are converted by the temperature signal acquisition module 2 and input into the controller 1 in the unit control cabinet. The controller 1 uses the collected exhaust temperature signal and cylinder temperature signal as closed-loop control signals.

[0044] In a multi-cylinder engine, taking the exhaust temperature and cylinder temperature control of a certain cylinder as an example, the exhaust temperature of all cylinders corresponding to the load target is obtained according to the load of the engine operation, wherein 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, and then the opening flow of the gas solenoid valve 3 is corrected, affecting the air-fuel ratio in the engine combustion chamber, thereby controlling the exhaust temperature and cylinder temperature. When it is detected that 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, thereby controlling the real-time exhaust temperature value and the real-time cylinder temperature value to be within the target value range.

[0045] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention. These modifications and improvements will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A fuel control method for a large-cylinder high-power gas engine, characterized in that: The method is to set the exhaust temperature target value and the cylinder temperature limit value; Collecting a real-time exhaust temperature value, and calibrating a target opening of the gas solenoid valve according to the real-time exhaust temperature value and the exhaust temperature target value; collecting a real-time cylinder temperature value, and determining whether to correct the gas solenoid valve based on the real-time cylinder temperature value and a cylinder temperature limit value; when the real-time cylinder temperature value is greater than the cylinder temperature limit value, obtaining a correction coefficient for the opening of the gas solenoid valve based on a ratio analysis result between the real-time cylinder temperature value and the cylinder temperature limit value; The final opening of the gas solenoid valve is obtained according to the target opening of the gas solenoid valve and the correction coefficient.

2. The fuel control method for a large-cylinder high-power gas engine according to claim 1, characterized in that: The method for calibrating the target gas opening is: An exhaust temperature difference is obtained by subtracting the real-time exhaust temperature value from the exhaust temperature target value, and a target opening corresponding to the exhaust temperature difference is obtained by querying a load target exhaust temperature curve.

3. The fuel control method for a large-cylinder high-power gas engine according to claim 2, characterized in that: 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.

4. The fuel control method for a large-cylinder high-power gas engine according to claim 1, characterized in that: 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.

5. A fuel control system for a large-cylinder, high-power gas engine, characterized in that: It includes, The exhaust temperature sensor is installed in the exhaust duct of the engine combustion chamber to collect real-time exhaust temperature signals; A cylinder temperature sensor is installed in the intake duct of the engine combustion chamber and is used to collect real-time cylinder temperature signals; A gas solenoid valve is installed at the connection between the gas pipeline and the air inlet of the engine combustion chamber to control the inlet and outlet of the gas; The controller controls the opening of the gas solenoid valve according to the real-time exhaust temperature signal and the real-time cylinder temperature signal using the control method described in any one of claims 1 to 4.

6. A fuel control system for a large-cylinder, high-power gas engine according to claim 5, characterized in that: The controller is electrically connected to the cylinder temperature sensor and the exhaust temperature sensor respectively through the temperature signal acquisition module.

7. The fuel control system for a large-cylinder, high-power gas engine according to claim 5, characterized in that: The controller is a PLC.

Images