CN-121976886-A - Combustion regulation and control method of diesel-natural gas dual-fuel in-cylinder direct injection engine

CN121976886ACN 121976886 ACN121976886 ACN 121976886ACN-121976886-A

Abstract

The invention discloses a combustion regulation method of a direct injection engine in a diesel-natural gas dual-fuel cylinder, relates to the direct injection engine in the dual-fuel cylinder, and solves the technical problems of unstable engine combustion, low combustion efficiency and increased emission caused by unbalanced energy distribution ratio of diesel and natural gas and unreasonable cooperation of injection strategies between the dual-fuel under different existing load working conditions. The method comprises the steps of calibrating the proportion of diesel oil driving accounting for total energy, setting diesel oil injection quantity and natural gas injection quantity according to the proportion of the diesel oil driving accounting for total energy, setting secondary correction injection pressure, a final main injection angle, a final pre-injection quantity and a final pre-injection angle of diesel oil according to the diesel oil injection quantity, setting natural gas injection pressure, natural gas injection angle and natural gas injection pulse width according to the natural gas injection quantity, and setting final main injection pressure of diesel oil according to the secondary correction injection pressure and the natural gas injection pressure. The invention realizes the efficient clean combustion of the engine under different working conditions.

Inventors

GUO XIAOYU
WANG HUI
LIN TIEJIAN
LIU XING
HUANG YONGJIE
WANG XIAOHUI
ZHAO LINGMENG
SU YITONG

Assignees

广西玉柴机器股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260228

Claims (10)

1. The method is characterized by comprising the steps of obtaining engine torque and engine rotating speed, calibrating the proportion of diesel oil driving occupied total energy according to the engine torque and the engine rotating speed, multiplying the proportion of the diesel oil driving occupied total energy by the engine torque to obtain diesel oil distribution torque, setting diesel oil injection quantity according to the diesel oil distribution torque, and setting a final main injection angle, a final pre-injection quantity and a final pre-injection angle of diesel oil according to the diesel oil injection quantity; and determining the proportion of the total energy of the natural gas drive according to the proportion of the total energy of the diesel, multiplying the proportion of the total energy of the natural gas drive by the engine torque to obtain natural gas distribution torque, determining the natural gas injection quantity according to the natural gas distribution torque, setting the natural gas injection pressure, the natural gas injection angle and the natural gas injection pulse width according to the natural gas injection quantity, and setting the final main injection pressure of the diesel according to the diesel injection quantity and the natural gas injection pressure.
2. The method for controlling combustion in a direct injection engine for a diesel-natural gas dual fuel cylinder according to claim 1, wherein the method for setting the final main injection angle of diesel according to the injection amount of diesel is, The method comprises the steps of calibrating a diesel injection angle basic value according to the engine speed and the diesel injection quantity, obtaining an ambient temperature, calibrating an oil injection correction angle according to the ambient temperature and the engine speed, adding the diesel injection angle basic value and the oil injection correction angle to obtain an oil injection preliminary correction angle value, obtaining an ambient pressure, calibrating an oil injection angle correction coefficient according to the ambient pressure and the engine speed, and multiplying the oil injection preliminary correction angle value and the oil injection angle correction coefficient to obtain a final main injection angle.
3. The method for setting the final main injection pressure of diesel according to the diesel injection quantity and the natural gas injection pressure is characterized in that an injection pressure basic value is calibrated according to the engine rotating speed and the diesel injection quantity, an ambient temperature is obtained, a diesel correction pressure is calibrated according to the ambient temperature and the engine rotating speed, the injection pressure basic value and the diesel correction pressure are added to obtain a primary correction injection pressure, the ambient pressure is obtained, a diesel pressure correction coefficient is calibrated according to the ambient pressure and the engine rotating speed, the primary correction injection pressure and the diesel pressure correction coefficient are multiplied to obtain a secondary correction injection pressure, a diesel rail pressure correction value based on the natural gas pressure is set according to the natural gas injection pressure and the secondary correction injection pressure, and the secondary correction injection pressure and the diesel rail pressure correction value based on the natural gas pressure are added to obtain the final main injection pressure.
4. The method for controlling combustion of a direct injection engine in a diesel-natural gas dual fuel cylinder according to claim 3, wherein the method for setting the correction value of the rail pressure of the diesel based on the natural gas pressure is, Setting a differential pressure threshold, obtaining an injection pressure difference value by the secondary correction injection pressure and the natural gas injection pressure difference, comparing the injection pressure difference value with the differential pressure threshold, and when the injection pressure difference value is smaller than the differential pressure threshold, setting the diesel rail pressure correction value based on the natural gas pressure to be zero; And when the injection pressure difference value is larger than or equal to the pressure difference threshold value, calibrating a diesel rail pressure correction value based on natural gas pressure according to the engine rotating speed and the injection pressure difference value.
5. The combustion regulation and control method of the diesel-natural gas dual-fuel in-cylinder direct injection engine according to claim 1 is characterized in that the method for setting the final pre-injection quantity and the final pre-injection angle according to the diesel injection quantity comprises the steps of calibrating the final pre-injection quantity according to the engine speed and the diesel injection quantity, and calibrating the final pre-injection angle according to the engine speed and the diesel injection quantity.
6. The method for controlling combustion of a direct injection engine in a diesel-natural gas dual fuel cylinder according to claim 1, wherein the method for setting the natural gas injection pulse width according to the natural gas injection amount is, The natural gas injection pulse width correction method comprises the steps of calibrating a natural gas injection pulse width basic value according to the engine rotating speed and the natural gas injection quantity, obtaining an ambient temperature, calibrating a natural gas correction pulse width according to the ambient temperature and the engine rotating speed, adding the natural gas injection pulse width basic value and the natural gas correction pulse width to obtain a natural gas preliminary correction pulse width value, obtaining an ambient pressure, calibrating a natural gas pulse width correction coefficient according to the ambient pressure and the engine rotating speed, and multiplying the natural gas preliminary correction pulse width value and the natural gas pulse width correction coefficient to obtain the natural gas injection pulse width.
7. The method for controlling combustion in a direct injection engine for a diesel-natural gas dual fuel cylinder according to claim 1, wherein the method for setting the natural gas injection angle according to the natural gas injection amount is, The natural gas injection angle correction method comprises the steps of calibrating a natural gas injection angle basic value according to the engine rotating speed and the natural gas injection quantity, obtaining an environment temperature, calibrating a natural gas injection correction angle according to the environment temperature and the engine rotating speed, adding the natural gas injection angle basic value and the natural gas injection correction angle to obtain a natural gas preliminary correction angle value, obtaining an environment pressure, calibrating a natural gas injection angle correction coefficient according to the environment pressure and the engine rotating speed, and multiplying the natural gas preliminary correction angle value and the natural gas injection angle correction coefficient to obtain the natural gas injection angle.
8. The method for controlling combustion in a direct injection engine for a diesel-natural gas dual fuel cylinder according to claim 1, wherein the method for setting the natural gas injection pressure according to the natural gas injection amount is, The natural gas injection pressure correction method comprises the steps of calibrating a natural gas injection pressure basic value according to the engine rotating speed and the natural gas injection quantity, obtaining an ambient temperature, calibrating a natural gas injection correction pressure according to the ambient temperature and the engine rotating speed, adding the natural gas injection pressure basic value and the correction pressure to obtain a natural gas injection preliminary correction pressure value, obtaining an ambient pressure, calibrating a natural gas injection pressure correction coefficient according to the ambient pressure and the engine rotating speed, and multiplying the natural gas injection preliminary correction pressure value and the natural gas injection pressure correction coefficient to obtain the natural gas injection pressure.
9. The combustion control method of the diesel-natural gas dual-fuel in-cylinder direct injection engine according to claim 1, wherein the method for determining the natural gas injection quantity according to the natural gas distribution torque is to calibrate the natural gas injection quantity according to the natural gas distribution torque and the engine speed.
10. The method for controlling combustion of a direct injection engine in a diesel-natural gas dual-fuel cylinder according to claim 1, wherein the method for determining the diesel injection amount according to the diesel distribution torque is to calibrate the diesel injection amount according to the diesel distribution torque and the engine speed.

Description

Combustion regulation and control method of diesel-natural gas dual-fuel in-cylinder direct injection engine Technical Field The invention relates to a direct injection engine in a dual-fuel cylinder, in particular to a combustion regulation method of a direct injection engine in a diesel-natural gas dual-fuel cylinder. Background With the increasing severity of energy crisis and environmental pollution problems, the search for efficient, clean engine combustion technology is a hotspot in current research. The diesel engine has higher thermal efficiency but more pollutant emission, and the natural gas as a clean fuel has the advantage of low emission. The dual-fuel engine combining diesel oil and natural gas can integrate the advantages of the diesel oil and the natural gas, and is an important technical approach for realizing energy conservation and emission reduction in the traffic field. However, unlike dual fuel engines employing natural gas port injection and direct injection in the diesel cylinder, when both diesel and natural gas are in direct injection in the same injector, there are still problems in combustion control, such as difficulty in precisely controlling the injection amounts and angles of diesel and natural gas under different load conditions, low efficiency of diesel ignition natural gas, unstable engine combustion, low combustion efficiency, and increased emissions. Disclosure of Invention The invention aims to solve the technical problems of unstable combustion, low combustion efficiency and increased emission of an engine caused by unbalanced energy distribution ratio of diesel and natural gas and unreasonable cooperation of injection strategies between dual fuels under different load working conditions in the prior art. The invention relates to a combustion regulation method of a diesel-natural gas dual-fuel in-cylinder direct injection engine, which comprises the steps of obtaining engine torque and engine rotating speed, calibrating the proportion of diesel drive to total energy according to the engine torque and the engine rotating speed, multiplying the proportion of the total energy to the diesel drive by the engine torque to obtain diesel distribution torque, setting diesel injection quantity according to the diesel distribution torque, and setting a final main injection angle, a final pre-injection quantity and a final pre-injection angle of diesel according to the diesel injection quantity; and determining the proportion of the total energy of the natural gas drive according to the proportion of the total energy of the diesel, multiplying the proportion of the total energy of the natural gas drive by the engine torque to obtain natural gas distribution torque, determining the natural gas injection quantity according to the natural gas distribution torque, setting the natural gas injection pressure, the natural gas injection angle and the natural gas injection pulse width according to the natural gas injection quantity, and setting the final main injection pressure of the diesel according to the diesel injection quantity and the natural gas injection pressure. Further improved, the method for setting the final main injection angle of the diesel oil according to the injection quantity of the diesel oil is that, The method comprises the steps of calibrating a diesel injection angle basic value according to the engine speed and the diesel injection quantity, obtaining an ambient temperature, calibrating an oil injection correction angle according to the ambient temperature and the engine speed, adding the diesel injection angle basic value and the oil injection correction angle to obtain an oil injection preliminary correction angle value, obtaining an ambient pressure, calibrating an oil injection angle correction coefficient according to the ambient pressure and the engine speed, and multiplying the oil injection preliminary correction angle value and the oil injection angle correction coefficient to obtain a final main injection angle. The method for setting the final main injection pressure of the diesel according to the diesel injection quantity comprises the steps of calibrating an injection pressure basic value according to the engine rotating speed and the diesel injection quantity, obtaining an environment temperature, calibrating a diesel correction pressure according to the environment temperature and the engine rotating speed, adding the injection pressure basic value and the diesel correction pressure to obtain a primary correction injection pressure, obtaining the environment pressure, calibrating a diesel pressure correction coefficient according to the environment pressure and the engine rotating speed, multiplying the primary correction injection pressure and the diesel pressure correction coefficient to obtain a secondary correction injection pressure, setting a diesel rail pressure correction value based on the natural gas pressure according to the natural gas