CN116988869A - Combustion control system and control method for gas ignition engine - Google Patents

Combustion control system and control method for gas ignition engine Download PDF

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Publication number
CN116988869A
CN116988869A CN202310986477.0A CN202310986477A CN116988869A CN 116988869 A CN116988869 A CN 116988869A CN 202310986477 A CN202310986477 A CN 202310986477A CN 116988869 A CN116988869 A CN 116988869A
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CN
China
Prior art keywords
gas
air
excess air
controller
air flow
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Pending
Application number
CN202310986477.0A
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Chinese (zh)
Inventor
周申申
陈铁
张鹏
王明卿
李东
张东雨
杨茜
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FAW Jiefang Automotive Co Ltd
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FAW Jiefang Automotive Co Ltd
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Priority to CN202310986477.0A priority Critical patent/CN116988869A/en
Publication of CN116988869A publication Critical patent/CN116988869A/en
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B43/00—Engines characterised by operating on gaseous fuels; Plants including such engines
    • F02B43/10—Engines or plants characterised by use of other specific gases, e.g. acetylene, oxyhydrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F02D19/021—Control of components of the fuel supply system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F02D19/026—Measuring or estimating parameters related to the fuel supply system
    • F02D19/027—Determining the fuel pressure, temperature or volume flow, the fuel tank fill level or a valve position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0002—Controlling intake air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D45/00—Electrical control not provided for in groups F02D41/00 - F02D43/00
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0203—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels characterised by the type of gaseous fuel
    • F02M21/0215—Mixtures of gaseous fuels; Natural gas; Biogas; Mine gas; Landfill gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/023—Valves; Pressure or flow regulators in the fuel supply or return system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/0248—Injectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B43/00—Engines characterised by operating on gaseous fuels; Plants including such engines
    • F02B43/10—Engines or plants characterised by use of other specific gases, e.g. acetylene, oxyhydrogen
    • F02B2043/103—Natural gas, e.g. methane or LNG used as a fuel
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/30—Use of alternative fuels, e.g. biofuels

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

The invention discloses a combustion control system and a control method of a gas ignition engine, wherein the control system comprises: the controller is used for determining fresh air demand according to the torque required by a driver in the current working cycle, and calculating the gas demand according to the equivalent air-fuel ratio, the required excess air coefficient set value and the excess air coefficient correction coefficient; the controller is used for controlling the opening of the throttle valve regulating valve after acquiring the actual air flow so as to realize closed-loop control of the fresh air demand; the controller is used for controlling the gas nozzle to spray gas according to the gas demand after the fresh air demand is reached; and performing closed-loop control with a required excess air coefficient set value according to the obtained excess air coefficient measured value in the waste gas in the current working cycle, and outputting an excess air coefficient correction coefficient. The invention can ensure that the fuel gas and the air quantity are equivalent or lean combusted according to the set value of the excess air coefficient required, and ensure the economy and the stability of the gas ignition engine.

Description

Combustion control system and control method for gas ignition engine
Technical Field
The invention relates to the technical field of automobiles, in particular to a combustion control system and a control method of a gas ignition engine.
Background
Compared with a diesel engine with the same displacement, the gas ignition engine such as a natural gas engine has the advantages of close dynamic property, obvious environmental protection advantage and easier meeting of the requirements of stricter and stricter emission regulations, and mainstream engine manufacturers at home and abroad can see the situation and put forward the gas ignition engine model in a dispute. The lean combustion mode can greatly reduce the fuel gas consumption rate of the engine, but is limited by lean combustion boundaries, so that the gas ignition engine is unstable. Equivalent combustion can ensure stable combustion of the engine, but the required gas demand is more. Because of the influence of temperature and other conditions, the fresh air demand and the gas demand can not reach the actual demand due to lean combustion and equivalent combustion, so that the gas ignition engine is unstable and cannot reach the economic combustion.
Disclosure of Invention
The invention provides a combustion control system and a control method for a gas ignition engine, which can ensure that the fuel gas amount and the air amount are subjected to equivalent/lean combustion according to the set value of the excess air coefficient required, and ensure the economy and the stability of the gas ignition engine.
According to an aspect of the present invention, there is provided a gas-fired engine combustion control system comprising:
the system comprises a gas nozzle, an air flow sensor, a throttle valve, an air-gas mixer, a raw exhaust line oxygen concentration sensor, an engine and a controller;
a gas nozzle is arranged at the inlet of the gas pipeline; the air flow sensor and the throttle valve are arranged on the air pipeline, and the first end of the throttle valve is connected with the air flow sensor; the second end of the throttle valve is connected with the first end of the air-gas mixer through an air pipeline, and the second end of the air-gas mixer is connected with a gas pipeline; the third end of the air-gas mixer is connected with the first end of the engine, and an original exhaust line oxygen concentration sensor is arranged on an exhaust gas pipeline of the second end of the engine; the air-gas mixer is used for mixing air and gas;
the controller is respectively and electrically connected with the gas nozzle, the air flow sensor, the throttle valve and the original exhaust line oxygen concentration sensor;
the controller is used for determining fresh air demand according to engine torque in the current working cycle, and calculating fuel gas demand according to the equivalent air-fuel ratio, the required excess air coefficient set value and the excess air coefficient correction coefficient;
the air flow sensor is used for detecting the actual air flow; the controller is used for controlling the throttle valve to adjust the opening of the valve according to the actual air flow after obtaining the actual air flow so as to enable the actual air flow to reach the fresh air demand and realize air flow closed-loop control;
the controller is also used for controlling the gas nozzle to spray gas according to the gas demand after determining that the actual air flow reaches the fresh air demand;
the original bus line oxygen concentration sensor is used for detecting an excess air coefficient measured value in the exhaust gas in the current working cycle, and the controller is also used for determining an excess air coefficient correction coefficient in the next working cycle according to the obtained excess air coefficient measured value in the current working cycle, so that the closed-loop control of the gas quantity is realized.
Alternatively, if the fuel gas is natural gas, the excess air ratio is set to 1.
Alternatively, if the fuel gas is hydrogen, the excess air ratio is set to 2.5.
Optionally, the controller is configured to determine the excess air factor correction factor based on a ratio between a measured excess air factor in the exhaust gas and a desired excess air factor set point in the current operating cycle.
Optionally, the controller is configured to determine the first excess air factor correction coefficient according to a ratio between the excess air factor measurement value in the exhaust gas in the current working cycle and the required excess air factor set value when the excess air factor measurement value in the current working cycle is greater than the required excess air factor set value, so as to increase the amount of gas injected by the gas nozzle in the next working cycle.
Optionally, the controller is configured to determine a second excess air factor correction coefficient according to a ratio between the excess air factor measurement value in the exhaust gas in the current working cycle and the required excess air factor set value when the excess air factor measurement value in the current working cycle is equal to the required excess air factor set value, so as to keep the gas quantity injected by the gas nozzle in the next working cycle consistent with the gas quantity injected by the gas nozzle in the current working cycle.
Optionally, the controller is configured to determine a third excess air factor correction coefficient according to a ratio between the excess air factor measurement value in the exhaust gas in the current working cycle and the required excess air factor set value when the excess air factor measurement value in the current working cycle is smaller than the required excess air factor set value, so as to reduce the amount of gas injected by the gas nozzle in the next working cycle.
Optionally, the gas-fired engine combustion control system further comprises:
and the three-way catalyst is arranged between the original exhaust line oxygen concentration sensor and the exhaust outlet and is used for purifying the exhaust.
According to another aspect of the present invention, there is provided a gas-fired engine combustion control method, the gas-fired engine combustion control system comprising: the device comprises a gas nozzle, an air flow sensor, a throttle valve, an air-gas mixer, an original exhaust line oxygen concentration sensor and a controller;
a gas nozzle is arranged at the inlet of the gas pipeline; the air flow sensor and the throttle valve are arranged on the air pipeline, and the first end of the throttle valve is connected with the air flow sensor; an air pipeline at the second end of the throttle valve is connected with the first end of the air-gas mixer, and the second end of the air-gas mixer is connected with the gas pipeline; the exhaust pipeline of the second end of the engine is provided with an original exhaust line oxygen concentration sensor; the air-gas mixer is used for mixing air and gas;
the controller is respectively and electrically connected with the gas nozzle, the air flow sensor, the throttle valve and the original exhaust line oxygen concentration sensor; the air flow sensor is used for detecting the actual air flow; the original exhaust line oxygen concentration sensor is used for detecting the excess air ratio measurement value in the exhaust gas in the current working cycle,
the gas ignition engine combustion control method includes:
the controller determines fresh air demand according to engine torque and calculates fuel gas demand according to the equivalent air-fuel ratio, the required excess air factor set value and the excess air factor correction coefficient in the current working cycle;
the controller acquires the actual air flow and then controls the throttle valve to adjust the opening of the valve according to the actual air flow so as to enable the actual air flow to reach the fresh air demand, and air flow closed-loop control is realized;
after the controller determines that the actual air flow reaches the fresh air demand, the controller controls the gas nozzle to spray gas according to the gas demand;
and the controller determines an excess air coefficient correction coefficient in the next working cycle according to the obtained excess air coefficient measured value in the current working cycle, so as to realize closed-loop control of the fuel gas.
Optionally, the controller determines an excess air factor correction coefficient in a next working cycle according to the obtained excess air factor measurement value in the current working cycle, including:
the controller determines an excess air ratio correction factor based on a ratio between the excess air ratio measurement in the exhaust gas and the desired excess air ratio setpoint in the current operating cycle.
According to the technical scheme, a gas nozzle, an air flow sensor, a throttle valve, an air-gas mixer, an original exhaust line oxygen concentration sensor, an engine and a controller are arranged; the controller is used for determining fresh air demand according to the torque required by a driver in the current working cycle, and calculating the gas demand according to the equivalent air-fuel ratio, the required excess air coefficient set value and the excess air coefficient correction coefficient; the air flow sensor is used for detecting the actual air flow; the controller is used for controlling the throttle valve to adjust the opening of the valve according to the actual air flow after obtaining the actual air flow so as to enable the actual air flow to reach the fresh air demand and realize air flow closed-loop control; the controller is also used for controlling the gas nozzle to spray gas according to the gas demand after determining that the actual air flow reaches the fresh air demand; the original bus line oxygen concentration sensor is used for detecting an excess air coefficient measured value in the exhaust gas in the current working cycle, and the controller is also used for determining an excess air coefficient correction coefficient in the next working cycle according to the obtained excess air coefficient measured value in the current working cycle, so that the closed-loop control of the gas quantity is realized. The invention can detect the actual air flow in real time by arranging the air flow sensor and transmit the actual air flow value to the controller, the controller controls and adjusts the opening of the throttle valve according to the obtained actual air flow value so as to ensure that the actual air flow reaches the fresh air demand value, and the fuel gas demand is corrected by the excess air coefficient correction coefficient, so that the fuel gas and the air quantity can be ensured to perform equivalent or lean combustion according to the required excess air coefficient set value, and the economy and the stability of the gas ignition engine are ensured.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a combustion control system for a gas-fired engine according to an embodiment of the present invention;
fig. 2 is a flowchart of a combustion control method of a gas ignition engine according to a second embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Example 1
An embodiment of the present invention provides a combustion control system of a gas-ignition engine, and fig. 1 is a schematic structural diagram of a combustion control system of a gas-ignition engine provided in an embodiment of the present invention, and referring to fig. 1, the combustion control system of a gas-ignition engine includes: a gas nozzle 10, an air flow sensor 20, a throttle valve 30, an air-gas mixer 40, an original exhaust gas oxygen concentration sensor 50, an engine 60, and a controller; a gas nozzle 10 is arranged at the inlet of the gas pipeline; the air flow sensor 20 and the throttle valve 30 are arranged on the air pipe, and a first end of the throttle valve 30 is connected with the air flow sensor 20; the second end of the throttle valve 30 is connected with the first end of the air-gas mixer 40 through an air pipeline, and the second end of the air-gas mixer 40 is connected with a gas pipeline; the third end of the air-gas mixer 40 is connected with the first end of the engine 60, and an original exhaust line oxygen concentration sensor 50 is arranged on an exhaust gas pipeline of the second end of the engine 60; the air-gas mixer 40 is for mixing air and gas; the controller is electrically connected to the gas nozzle 10, the air flow sensor 20, the throttle valve 30, and the raw exhaust oxygen concentration sensor 50, respectively.
The controller is used for determining fresh air demand according to the torque required by a driver in the current working cycle, and calculating the gas demand according to the equivalent air-fuel ratio, the required excess air coefficient set value and the excess air coefficient correction coefficient; the air flow sensor 20 is for detecting an actual air flow; the controller is used for controlling the throttle valve 30 to adjust the opening of the valve according to the actual air flow after acquiring the actual air flow so as to enable the actual air flow to reach the fresh air demand, and air flow closed-loop control is realized; the controller is further used for controlling the gas nozzle 10 to spray gas according to the gas demand after determining that the actual air flow reaches the fresh air demand; the original exhaust line oxygen concentration sensor 50 is used for detecting an excess air coefficient measured value in exhaust gas in a current working cycle, and the controller is also used for determining an excess air coefficient correction coefficient in a next working cycle according to the obtained excess air coefficient measured value in the current working cycle, so that the closed-loop control of the fuel gas is realized.
Wherein the controller is not shown in fig. 1, the fuel gas may be natural gas or hydrogen. In the current duty cycle, the controller determines the driver demand torque when detecting the pedal opening degree that the driver has stepped on, and determines the fresh air demand amount according to the driver demand torque, and the controller controls the valve opening degree of the throttle valve 30 according to the actual air flow rate detected by the air flow rate sensor 20, and, illustratively, if the detected actual air flow rate is smaller than the fresh air demand amount, the valve opening degree of the throttle valve 30 is increased by the controller; if the detected actual air flow rate is equal to the fresh air demand, the valve opening of the throttle valve 30 is controlled by the controller to be maintained so that the actual air flow rate reaches the fresh air demand. The air flow sensor 20 can detect the actual air flow in real time, and the actual air flow value obtained by the controller controls and adjusts the opening of the throttle valve 30 to ensure that the actual air flow reaches the fresh air demand value, so as to realize air flow closed-loop control to meet the driving demand of a driver.
Specifically, the controller calculates the fuel gas demand according to the equivalent air-fuel ratio, the required excess air factor set value, the excess air factor correction coefficient and the fresh air demand, and by way of example, the required excess air factor set value may be 1 or 2.5, when the required excess control coefficient set value is 1, the controller may determine that the fuel gas is equivalent combusted, and under the condition of equivalent combustion, the condition that the fresh air demand and the fuel gas demand are required to be combusted in a ratio of 1:1 is required; when the set value of the excess control coefficient of the hydrangea is 2.5, the hydrangea can be determined to be lean combustion, and under the condition of lean combustion, the condition that the fresh air demand and the fuel gas demand are in 2.5:1 combustion is required; equivalent combustion or lean combustion control of the gas-fired engine can be achieved by setting the demand excess control factor set point. In the initial working process, the excess air coefficient correction coefficient can be zero, and the combustion is carried out according to the ratio of fresh air demand and gas demand in equivalent combustion or lean combustion, but in the working process, the condition of lean combustion and lean combustion is influenced by temperature and other conditions, so that the excess air coefficient correction coefficient is required to be corrected, the excess air coefficient correction coefficient is used for correcting the gas quantity, the closed-loop control of the gas quantity is realized, the equivalent combustion or lean combustion of the gas quantity and the air quantity according to the required excess air coefficient set value can be ensured, and the economy and the stability of the gas ignition engine are ensured.
The excess air coefficient measured value reflects the air measured value in the air and the exhaust gas after the gas combustion, and the controller judges whether the gas quantity in the current working cycle is slightly rich or slightly lean according to the obtained excess air coefficient measured value in the current working cycle, so that the excess air coefficient correction coefficient in the next working cycle is determined according to the excess air coefficient measured value. For example, if the controller detects that the measured value of the excess air ratio in the exhaust gas in the current working cycle is greater than the set value of the excess air ratio demand control coefficient in the case of equivalent combustion, it indicates that the gas demand in the current working cycle is slightly lean, the gas demand is increased in the next working cycle, the gas demand to be increased is the excess air ratio demand correction coefficient, and in the next working cycle, the controller controls the gas nozzle to inject the gas according to the equivalent air-fuel ratio, the set value of the excess air ratio demand, the excess air ratio correction coefficient and the calculated gas demand of fresh air demand.
According to the technical scheme, a gas nozzle 10, an air flow sensor 20, a throttle valve 30, an air-gas mixer 40, an original exhaust line oxygen concentration sensor 50, an engine 60 and a controller are arranged; the controller is used for determining fresh air demand according to the torque required by a driver in the current working cycle, and calculating the gas demand according to the equivalent air-fuel ratio, the required excess air coefficient set value and the excess air coefficient correction coefficient; the air flow sensor 20 is for detecting an actual air flow; the controller is used for controlling the throttle valve 30 to adjust the opening of the valve according to the actual air flow after acquiring the actual air flow so as to enable the actual air flow to reach the fresh air demand; the controller is further used for controlling the gas nozzle 10 to spray gas according to the gas demand after determining that the actual air flow reaches the fresh air demand; the original exhaust gas concentration sensor 50 is used for detecting an excess air ratio measurement value in the exhaust gas in the current working cycle, and the controller is also used for determining an excess air ratio correction coefficient in the next working cycle according to the obtained excess air ratio measurement value in the current working cycle. The invention can detect the actual air flow in real time by arranging the air flow sensor 20 and transmit the actual air flow value to the controller, the controller controls and adjusts the valve opening of the throttle valve 30 according to the obtained actual air flow value so as to ensure that the actual air flow reaches the fresh air demand value, and the invention can ensure that the fuel gas and the air quantity are equivalent or lean combusted according to the required excess air coefficient set value by correcting the excess air coefficient and ensure the economy and the stability of the gas ignition engine. .
Alternatively, if the fuel gas is natural gas, the excess air ratio is set to 1.
If the fuel gas is natural gas, if the set value of the excess air coefficient is 2.5, the fuel gas is combusted in a lean combustion mode, and the natural gas can easily reach the lean combustion boundary, so that the gas ignition engine is unstable in operation; therefore, the fuel gas is natural gas, the required excess air coefficient is set to be 1, and the fuel gas is combusted in an equivalent combustion mode, so that the stability of the gas ignition engine can be ensured. The equivalent combustion or lean combustion control of the gas ignition engine can be realized by setting the required excess air coefficient set value, so that the flexible experiment of the gas ignition engine under different gas conditions is realized.
Alternatively, if the fuel gas is hydrogen, the excess air ratio is set to 2.5.
If the gas is hydrogen, the gas ignition engine is stable by adopting an equivalent combustion mode if the required excess air coefficient set value is 1, but the gas demand is increased, and if the required excess air coefficient set value is 2.5, the gas ignition engine is combusted by adopting a lean combustion mode, the boundary of the hydrogen lean combustion is very high, and the gas ignition engine is not unstable in operation and can save the gas quantity. The equivalent combustion or lean combustion control of the gas ignition engine can be realized by setting the set value of the excess demand control coefficient, so that the flexible experiment of the gas ignition engine under different gas conditions is realized.
Optionally, the controller is configured to determine the excess air factor correction factor based on a ratio between a measured excess air factor in the exhaust gas and a desired excess air factor set point in the current operating cycle.
For example, if the ratio between the excess air ratio measured value and the required excess air ratio set value is greater than 1, it is indicated that there is a surplus air amount and the gas amount is slightly diluted, the gas demand is increased in the next working cycle, and the gas demand to be increased is the excess air ratio correction coefficient; if the ratio between the excess air coefficient measured value and the required excess air coefficient set value is smaller than 1, the gas quantity is slightly concentrated, the gas demand quantity is reduced in the next working cycle, and the gas demand quantity required to be reduced is the excess air coefficient correction coefficient; if the ratio between the excess air coefficient measured value and the required excess air coefficient set value is 1, maintaining the gas demand in the current working cycle in the next working cycle, wherein the excess air coefficient correction coefficient is zero; in the next working cycle, the controller controls the gas nozzle to inject gas according to the gas demand calculated by the equivalent air-fuel ratio, the required excess air coefficient set value, the excess air coefficient correction coefficient and the fresh air demand.
Optionally, the controller is configured to determine the first excess air ratio correction factor according to a ratio between the excess air ratio measurement value and the required excess air ratio set value when the excess air ratio measurement value in the current working cycle is greater than the required excess air ratio set value, so as to increase the amount of gas injected by the gas nozzle in the next working cycle.
When the measured value of the excess air coefficient in the current working cycle is larger than the set value of the excess air coefficient, the ratio between the measured value of the excess air coefficient and the set value of the excess air coefficient in the current working cycle is larger than 1, the air quantity is remained, the gas quantity is slightly lean, the gas demand is increased in the next working cycle, the gas demand to be increased is a first excess air coefficient correction coefficient, and in the next working cycle, the controller calculates the gas demand according to the equivalent air-fuel ratio, the set value of the excess air coefficient, the first excess air coefficient correction coefficient and the fresh air demand, so that the gas quantity sprayed by the gas nozzle in the next working cycle can be increased.
Optionally, the controller is configured to determine a second excess air factor correction coefficient according to a ratio between the excess air factor measurement value and the required excess air factor set value when the excess air factor measurement value in the current working cycle is equal to the required excess air factor set value, so as to keep the gas quantity injected by the gas nozzle in the next working cycle consistent with the gas quantity injected by the gas nozzle in the current working cycle.
When the measured value of the excess air coefficient in the current working cycle is equal to the required excess air coefficient set value, the ratio between the measured value of the excess air coefficient and the required excess air coefficient set value is 1, the gas required quantity in the current working cycle is maintained in the next working cycle, the second excess air coefficient correction coefficient is zero, and in the next working cycle, the controller calculates the gas required quantity according to the equivalent air-fuel ratio, the required excess air coefficient set value, the second excess air coefficient correction coefficient and the fresh air required quantity, so that the gas quantity sprayed by the gas nozzle in the next working cycle is consistent with the gas quantity sprayed by the gas nozzle in the current working cycle.
Optionally, the controller is configured to determine a third excess air ratio correction coefficient according to a ratio between the excess air ratio measurement value and the required excess air ratio set value when the excess air ratio measurement value in the current working cycle is smaller than the required excess air ratio set value, so as to reduce the amount of gas injected by the gas nozzle in the next working cycle.
When the measured value of the excess air coefficient in the current working cycle is smaller than the required excess air coefficient set value, the ratio between the measured value of the excess air coefficient and the required excess air coefficient set value is smaller than 1, which means that the gas quantity in the current working cycle is slightly thick, the gas demand quantity is reduced in the next working cycle, and the gas demand quantity required to be reduced is the excess air coefficient correction coefficient; in the next working cycle, the controller calculates the fuel gas demand according to the equivalent air-fuel ratio, the required excess air coefficient set value, the third excess air coefficient correction coefficient and the fresh air demand, and can reduce the fuel gas quantity sprayed by the fuel gas nozzle in the next working cycle.
Optionally, referring to fig. 1, the gas-ignition engine combustion control system further includes: a three-way catalyst 70, the three-way catalyst 70 being disposed between the raw exhaust gas concentration sensor 50 and the exhaust gas discharge port, the three-way catalyst 70 being for purifying the exhaust gas.
The three-way catalyst 70 may be used to purify tail gas Nitrogen Oxides (NOX) exhaust gas, meeting VI emission regulations.
Example two
The embodiment of the invention provides a combustion control method of a gas ignition engine based on the embodiment, and the combustion control system of the gas ignition engine comprises the following steps: the device comprises a gas nozzle, an air flow sensor, a throttle valve, an air-gas mixer, an original exhaust line oxygen concentration sensor and a controller;
a gas nozzle is arranged at the inlet of the gas pipeline; the air flow sensor and the throttle valve are arranged on the air pipeline, and the first end of the throttle valve is connected with the air flow sensor; the second end of the throttle valve is connected with the first end of the air-gas mixer through an air pipeline, and the second end of the air-gas mixer is connected with a gas pipeline; the third end of the air-gas mixer is connected with the first end of the engine, and an original exhaust line oxygen concentration sensor is arranged on an exhaust gas pipeline of the second end of the engine; the air-gas mixer is used for mixing air and gas;
the controller is respectively and electrically connected with the gas nozzle, the air flow sensor, the throttle valve and the original exhaust line oxygen concentration sensor; the air flow sensor is used for detecting the actual air flow; the original exhaust line oxygen concentration sensor is used for detecting an excess air coefficient measured value in the exhaust gas in the current working cycle;
fig. 2 is a flowchart of a combustion control method of a gas-ignition engine according to a second embodiment of the present invention, and referring to fig. 2, the combustion control method of the gas-ignition engine includes:
step 110, the controller determines a fresh air demand based on the driver demand torque and calculates a gas demand based on the equivalent air-fuel ratio, the desired over-air-factor set point, and the over-air-factor correction factor during the current duty cycle.
Step 120, after obtaining the actual air flow, the controller controls the throttle valve to adjust the opening of the valve according to the actual air flow so as to enable the actual air flow to reach the fresh air demand, and air flow closed-loop control is realized;
130, after the controller determines that the actual air flow reaches the fresh air demand, controlling the gas nozzle to spray gas according to the gas demand;
and 140, the controller determines an excess air coefficient correction coefficient in the next working cycle according to the obtained excess air coefficient measured value in the current working cycle, so as to realize closed-loop control of the gas quantity.
According to the combustion control method of the gas ignition engine, provided by the embodiment of the invention, the equivalent/lean combustion of the gas quantity and the air quantity according to the required excessive air coefficient set value can be ensured, and the economy and the stability of the gas ignition engine are ensured. Meanwhile, the equivalent combustion or lean combustion control of the gas ignition engine can be realized by only changing the set value of the excessive control coefficient.
Optionally, the controller determines an excess air factor correction coefficient in a next working cycle according to the obtained excess air factor measurement value in the current working cycle, including: the controller determines an excess air ratio correction factor based on a ratio between the excess air ratio measurement in the exhaust gas and the desired excess air ratio setpoint in the current operating cycle.
The method for controlling the combustion of the gas-fired engine provided by the technical scheme of the embodiment of the invention belongs to the same inventive concept and has the same beneficial effects as the gas-fired engine combustion control system provided by the embodiment of the invention, and the detailed technical details of the embodiment are not shown in the gas-fired engine combustion control system of any embodiment of the invention.
It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present invention may be performed in parallel, sequentially, or in a different order, so long as the desired results of the technical solution of the present invention are achieved, and the present invention is not limited herein.
The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims (10)

1. A gas-fired engine combustion control system, comprising:
the system comprises a gas nozzle, an air flow sensor, a throttle valve, an air-gas mixer, a raw exhaust line oxygen concentration sensor, an engine and a controller;
the gas nozzle is arranged at the inlet of the gas pipeline; the air flow sensor and the throttle valve are arranged on an air pipeline, and the first end of the throttle valve is connected with the air flow sensor; the second end of the throttle valve is connected with the first end of the air-gas mixer through an air pipeline, and the second end of the air-gas mixer is connected with a gas pipeline; the third end of the air-gas mixer is connected with the first end of the engine, and an original exhaust line oxygen concentration sensor is arranged on an exhaust gas pipeline of the second end of the engine; the air-gas mixer is used for mixing air and gas;
the controller is respectively and electrically connected with the gas nozzle, the air flow sensor, the throttle valve and the original exhaust line oxygen concentration sensor;
the controller is used for determining fresh air demand according to the torque required by a driver in the current working cycle, and calculating fuel gas demand according to the equivalent air-fuel ratio, the required excess air coefficient set value and the excess air coefficient correction coefficient; the air flow sensor is used for detecting the actual air flow; the controller is used for controlling the throttle valve to adjust the opening of the valve according to the actual air flow after acquiring the actual air flow so as to enable the actual air flow to reach the fresh air demand and realize air flow closed-loop control;
the controller is also used for controlling the gas nozzle to spray gas according to the gas demand after determining that the actual air flow reaches the fresh air demand;
the original exhaust line oxygen concentration sensor is used for detecting an excess air coefficient measured value in exhaust gas in a current working cycle, and the controller is also used for determining an excess air coefficient correction coefficient in a next working cycle according to the obtained excess air coefficient measured value in the current working cycle, so that closed-loop control of the fuel gas is realized.
2. The gas ignition engine combustion control system of claim 1, wherein the required excess air ratio set point is 1 if the gas is natural gas.
3. The gas ignition engine combustion control system of claim 1, wherein the required excess air ratio set point is 2.5 if the gas is hydrogen.
4. The gas ignition engine combustion control system of claim 1, wherein the controller is configured to determine an excess air ratio correction factor based on a ratio between the excess air ratio measurement in the exhaust gas and the desired excess air ratio setpoint in a current operating cycle.
5. The gas ignition engine combustion control system of claim 4, wherein the controller is configured to determine a first excess air ratio correction factor based on a ratio between the excess air ratio measurement in exhaust gas in a current operating cycle and a desired excess air ratio setting to increase an amount of fuel injected by the fuel gas nozzle in a next operating cycle when the excess air ratio measurement in the current operating cycle is greater than the desired excess air ratio setting.
6. The gas ignition engine combustion control system of claim 4, wherein the controller is configured to determine a second excess air ratio correction factor based on a ratio between the excess air ratio measurement in the exhaust gas in the current operating cycle and the desired excess air ratio setting to keep the amount of gas injected by the gas injection nozzle in the next operating cycle consistent with the amount of gas injected by the gas injection nozzle in the current operating cycle when the excess air ratio measurement in the current operating cycle is equal to the desired excess air ratio setting.
7. The gas ignition engine combustion control system of claim 4, wherein the controller is configured to determine a third excess air ratio correction factor based on a ratio between the excess air ratio measurement in the exhaust gas in the current operating cycle and the desired excess air ratio setting to reduce the amount of fuel injected by the fuel gas nozzle in the next operating cycle when the excess air ratio measurement in the current operating cycle is less than the desired excess air ratio setting.
8. The gas-fired engine combustion control system of claim 1, further comprising:
and the three-way catalyst is arranged between the original exhaust line oxygen concentration sensor and the exhaust outlet and is used for purifying exhaust.
9. A method of controlling combustion in a gas-fired engine, the gas-fired engine combustion control system comprising: the device comprises a gas nozzle, an air flow sensor, a throttle valve, an air-gas mixer, an original exhaust line oxygen concentration sensor and a controller;
the gas nozzle is arranged at the inlet of the gas pipeline; the air flow sensor and the throttle valve are arranged on an air pipeline, and the first end of the throttle valve is connected with the air flow sensor; an air pipeline at the second end of the throttle valve is connected with the first end of the air-gas mixer, and the second end of the air-gas mixer is connected with the gas pipeline; the exhaust pipeline of the second end of the engine is provided with an original exhaust line oxygen concentration sensor; the air-gas mixer is used for mixing air and gas;
the controller is respectively and electrically connected with the gas nozzle, the air flow sensor, the throttle valve and the original exhaust line oxygen concentration sensor; the air flow sensor is used for detecting the actual air flow; the original exhaust line oxygen concentration sensor is used for detecting an excess air coefficient measured value in the exhaust gas in the current working cycle;
the gas ignition engine combustion control method includes:
the controller determines fresh air demand according to the torque required by a driver in the current working cycle, and calculates fuel gas demand according to the equivalent air-fuel ratio, the required excess air coefficient set value and the excess air coefficient correction coefficient;
the controller acquires the actual air flow and then controls the throttle valve to adjust the opening of the valve according to the actual air flow so as to enable the actual air flow to reach the fresh air demand and realize air flow closed-loop control;
after the controller determines that the actual air flow reaches the fresh air demand, controlling the gas nozzle to spray gas according to the gas demand;
and the controller determines an excess air coefficient correction coefficient in the next working cycle according to the obtained excess air coefficient measured value in the current working cycle, so as to realize closed-loop control of the gas quantity.
10. The gas ignition engine combustion control method according to claim 9, wherein the controller determining an excess air ratio correction factor in a next operating cycle from the obtained excess air ratio measurement value in a current operating cycle, comprises:
the controller determines an excess air factor correction coefficient based on a ratio between a measured excess air factor in the exhaust gas and the desired excess air factor set point in the current duty cycle.
CN202310986477.0A 2023-08-07 2023-08-07 Combustion control system and control method for gas ignition engine Pending CN116988869A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310986477.0A CN116988869A (en) 2023-08-07 2023-08-07 Combustion control system and control method for gas ignition engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310986477.0A CN116988869A (en) 2023-08-07 2023-08-07 Combustion control system and control method for gas ignition engine

Publications (1)

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CN116988869A true CN116988869A (en) 2023-11-03

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Country Link
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