CN114526165A - Torque calibration method of ammonia-natural gas dual-fuel engine - Google Patents
Torque calibration method of ammonia-natural gas dual-fuel engine Download PDFInfo
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- CN114526165A CN114526165A CN202210097297.2A CN202210097297A CN114526165A CN 114526165 A CN114526165 A CN 114526165A CN 202210097297 A CN202210097297 A CN 202210097297A CN 114526165 A CN114526165 A CN 114526165A
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- 239000003345 natural gas Substances 0.000 title claims abstract description 62
- 239000000446 fuel Substances 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000012887 quadratic function Methods 0.000 claims abstract description 19
- 239000007789 gas Substances 0.000 claims abstract description 10
- 230000004043 responsiveness Effects 0.000 claims abstract description 10
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 32
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 21
- 238000012886 linear function Methods 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 7
- 229910021529 ammonia Inorganic materials 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 11
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 150000001298 alcohols Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003502 gasoline Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
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- 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
- F02D19/06—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
- F02D19/0639—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels
- F02D19/0642—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions
- F02D19/0644—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions the gaseous fuel being hydrogen, ammonia or carbon monoxide
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- 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
- F02D19/06—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
- F02D19/0639—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels
- F02D19/0642—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions
- F02D19/0647—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME]
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- 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
- F02D19/06—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
- F02D19/08—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed simultaneously using pluralities of fuels
- F02D19/081—Adjusting the fuel composition or mixing ratio; Transitioning from one fuel to the other
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- 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
- F02D19/06—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
- F02D19/08—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed simultaneously using pluralities of fuels
- F02D19/082—Premixed fuels, i.e. emulsions or blends
-
- 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
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- 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)
- Oil, Petroleum & Natural Gas (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
Abstract
The invention discloses a torque calibration method of an ammonia-natural gas dual-fuel engine, which comprises the following steps: taking the torque output of the automobile as a central target, and carrying out quadratic function model fitting calibration on the torque of the engine; the actual torque percentage sent by the engine electronic control unit is obtained to be close to a true value by calibrating the ammonia-natural gas mixing proportion, the physicochemical characteristics of the mixed gas and the like; completing the fitting calibration of the indicated torque percentage and the accelerator percentage under different rotating speeds of external characteristics; after the primary function model is obtained, under the basic calibration strategy of the throttle valve, and when the rotating speed of the dual-fuel engine is stable, the position of the throttle valve is finally obtained; and starting to control the responsiveness calibration torque output value of the supercharger according to the position of the throttle valve. The torque MAP of the ammonia-natural gas dual-fuel engine is obtained by calibration through the method provided by the invention, and the smoothness and the responsiveness of the torque output of the automobile are improved.
Description
Technical Field
The invention relates to the technical field of engine calibration, in particular to a torque calibration method of an ammonia-natural gas dual-fuel engine.
Background
Under the target background of 'carbon peak reaching and carbon neutralization', the traffic and transportation field faces more severe emission reduction pressure, and the low-carbon green transformation of the industry is urgently needed to be promoted to realize sustainable development. According to statistics, the carbon emission of the transportation industry of China accounts for 10.4% of the total carbon emission of China, and compared with European and American countries, the carbon emission control system has the characteristics of low ratio, high speed increasing speed and large emission reduction potential. Road transportation accounts for more than 85% of the total carbon emission of national transportation, wherein the carbon emission ratio of heavy commercial vehicles is nearly half, and the road transportation is the main body of carbon emission and the key point of emission reduction in the field of transportation. The traditional heavy commercial vehicle not only needs to be subjected to green low-carbon transformation, but also meets the requirement of a coach user on driving comfort, and the ammonia-natural gas dual-fuel engine becomes an important way for achieving the aim.
The dual fuel in the current market is the combination of diesel oil, gasoline, natural gas, alcohols, hydrogen and the like, besides hydrogen energy, other fuels contain carbon elements, and the transportation and storage of the hydrogen energy are the main technical difficulties of the application of the current hydrogen energy. The liquid ammonia has unique advantages in energy density, safety, storage, transportation and application, can achieve a remarkable carbon reduction effect by being mixed with natural gas according to a certain proportion and entering a cylinder for combustion, and the difficulty of controlling the ammonia-natural gas dual-fuel engine needs to be solved in the research and development and application processes.
In view of the above, the invention provides a torque calibration method of an ammonia-natural gas dual-fuel engine, which is used for obtaining a torque MAP of the ammonia-natural gas dual-fuel engine through calibration and can obviously improve the smoothness and the responsiveness of the torque output of an automobile.
Disclosure of Invention
The invention aims to provide a torque calibration method of an ammonia-natural gas dual-fuel engine, which is used for replacing partial natural gas to enable the engine to use ammonia fuel without carbon emission, fully gives out calibration torque of an ammonia-natural gas mixture under the condition of an air-fuel ratio of 13.8 under each working condition of the engine, so that the performance of the engine is kept optimal, and the torque output of an automobile is important for evaluating the power of the ammonia-natural gas dual-fuel engine and is also a source of the drivability feeling of a driver.
The invention provides a torque calibration method of an ammonia-natural gas dual-fuel engine, which comprises the following steps:
s1, taking the torque output of the automobile as a central target, and carrying out quadratic function model fitting calibration on the torque of the ammonia-natural gas dual-fuel engine, wherein the quadratic function model is as follows: (x) ax2+ bx, wherein a, b are not equal to 0;
s2, calibrating the physical and chemical properties of the mixture and the mixing ratio of the ammonia gas and the natural gas to obtain that the actual torque percentage sent by the electric control unit of the ammonia gas-natural gas dual-fuel engine is close to the true value;
s3, utilizing the actual torque percentage to be close to the real value, and carrying out fitting calibration on the indicated torque percentage and the throttle percentage according to a linear function model g (x) -kx, wherein k is not equal to 0, and at each rotating speed of the external characteristics;
s4, after the linear function model is obtained, under the basic calibration strategy of the throttle valve, when the rotating speed of the ammonia-natural gas dual-fuel engine is stable, the position of the throttle valve is finally obtained;
s5, according to the position of the throttle valve, starting to control the responsiveness calibration torque output value f (x) of the supercharger, establishing the relationship of a quadratic function model between the torque output value f (x) and the throttle valve x, and carrying out torque calibration, wherein f (x) is the torque output value of each rotating speed of the external characteristic, and x is the percentage of the throttle valve.
Preferably, the quadratic function model f (x) ax in step S12+ bx, where a has a value in the range of [ -1/4, -1/25 [ -1/4 [ ]]And b value range [24,45 ]]When a is-1/5 and b is 40, according to the function f (x) — (1/5) x2+40x, x takes the value [0,100]And fitting a calibrated torque MAP graph and recording data.
Preferably, in step S2, under the conditions of controlling the pressure of the mixed gas entering the engine to be 6bar, the temperature to be 20 ℃, the proportion of ammonia gas to be 30 percent and the proportion of natural gas to be 70 percent, according to the chemical reaction formula CH4+2O2＝＝CO2+2H2O、4NH3+3O2＝＝6H2O+2N2Calculating to obtain the air-fuel ratio of the mixed gas of 13.8 and the density of 0.73g/L, and obtaining the physical and chemical properties of the mixed gas according to the table look-up of the low calorific value of the natural gas fuel and the low calorific value of the ammonia gas fuel;
the torque control calibration enables the actual torque percentage sent by the electronic control unit of the ammonia-natural gas dual-fuel engine to be close to the true value, the rack torque and the friction torque are calibrated, the low calorific value of the ammonia-natural gas mixture is calibrated, and the torque coefficient is calibrated.
Preferably, the friction torque calibration method comprises the following steps:
s11, setting the indicated thermal efficiency and the intake pressure of the ammonia-natural gas dual-fuel engine to be lower than 1 atmosphere according to a certain numerical coefficient;
s12, at an idling point of 600rpm, changing a torque value in the friction torque table so that the dynamometer torque becomes 0;
and S13, setting the idle speed to different rotating speeds according to the friction torque table, and repeating the step S12 to obtain the friction torque at each rotating speed.
Preferably, the calibration of the thermal efficiency coefficient is that the torque of the rack is the net torque in the software, the coefficient is classified according to the rotating speed and the air inlet pressure, and the torque coefficient is the rotating speed point torque/the maximum indicated torque; the torque coefficient calibration method comprises the following steps:
s21, selecting a rotating speed point: selecting 5 points to fully represent an external characteristic curve;
s22, operating the coordinate point at a full throttle, and recording net indication torque;
after the steps are completed, the actual torque percentage sent by the electronic control unit of the ammonia-natural gas dual-fuel engine is close to the true value.
Preferably, the calibration of the indicated torque percentage and the throttle percentage is to establish a linear function model, and a torque percentage MAP is calibrated according to the model in a value range [1,5/3] of k, where k is equal to g (x) kx.
Preferably, the calibration steps of the throttle valve are as follows:
s31, in the throttle valve calibration unit, the rotating speed is divided into 600rpm, 700rpm and … 1900rpm according to the difference of 100rpm, and the torque percentage is calibrated according to the steps;
s32, recording the position of the throttle valve in the step S31 at each rotation speed, and repeating the step S31.
Preferably, the responsiveness of the supercharger obtains the torque output, the torque output is calibrated and fitted according to a quadratic function model, the rotating speed is divided into 600rpm, 700rpm and … 1900rpm according to the difference of 100rpm, and the position of the throttle valve is calibrated according to the steps.
The invention has the beneficial effects that:
the method comprises the following steps of establishing a quadratic function model between torque output and percent of an accelerator, establishing a relation of the quadratic function model between the torque percent and the percent of the accelerator, mixing the ammonia-natural gas fuel according to a certain proportion, controlling the air-fuel ratio to be 13.8 by a calibration equivalence ratio combustion mode, and ideally controlling the volume ratio of the ammonia to the natural gas to be 3: and 7, the engine torque of the ammonia-natural gas mixed fuel is kept stable, and the torque performance of the pure natural gas engine is not reduced.
Drawings
FIG. 1 is a schematic diagram of a torque calibration method for an ammonia-natural gas dual-fuel engine calibrated according to the present invention;
FIG. 2 is a torque output MAP graph obtained by the torque calibration method of the ammonia-natural gas dual-fuel engine calibrated according to the invention;
FIG. 3 is a schematic diagram of a quadratic function fitting calibration;
FIG. 4 is a schematic of a linear function fit calibration;
FIG. 5 is a graphical illustration of torque percent and throttle percent plotted against a linear function.
Detailed Description
The present invention will be further illustrated with reference to the following specific examples.
As shown in fig. 1, a torque calibration method for an ammonia-natural gas dual-fuel engine includes the following steps:
s1, taking the torque output of the automobile as a central target, and carrying out quadratic function model fitting calibration on the torque of the ammonia-natural gas dual-fuel engine, wherein the quadratic function model is as follows: (x) ax2+ bx, wherein a, b are not equal to 0;
s2, calibrating the physical and chemical properties of the mixture and the mixing ratio of the ammonia and the natural gas to obtain the actual torque percentage sent by the electric control unit of the ammonia and natural gas dual-fuel engine close to a true value;
s3, utilizing the actual torque percentage to be close to the real value, and carrying out fitting calibration on the indicated torque percentage and the throttle percentage according to a linear function model g (x) -kx, wherein k is not equal to 0, and at each rotating speed of the external characteristics;
s4, after the linear function model is obtained, under the basic calibration strategy of the throttle valve, when the rotating speed of the ammonia-natural gas dual-fuel engine is stable, the position of the throttle valve is finally obtained;
s5, according to the position of the throttle valve, starting to control the responsiveness calibration torque output value f (x) of the supercharger, establishing the relationship of a quadratic function model between the torque output value f (x) and the throttle valve x, and carrying out torque calibration, wherein f (x) is the torque output value of each rotating speed of the external characteristic, and x is the percentage of the throttle valve.
Torque output MAP graph, as shown in FIG. 2, based on the quadratic function model f (x) ax according to the present calibration method2+ bx, where a has a value in the range of [ -1/4, -1/25 [ -1/4 [ ]]And b value range [24,45 ]]When a is-1/5 and b is 40, according to the function f (x) — (1/5) x2+40x, as shown in FIG. 3, x takes the value [0,100]According to the curve fitted by the method shown in the figure 3, the corresponding torque of the engine at each rotating speed is distributed around the curve in the calibration process, the torque MAP is calibrated in the process of 0% to 100% of the accelerator, the result of the responsiveness between the torque output and the accelerator at each rotating speed obtained by data recording is verified on the bench again, and the smooth torque output is obtained.
The following steps are required before fig. 4 and 5:
controlling the pressure of mixed gas entering the engine to be 6bar, the temperature to be 20 ℃, the proportion of ammonia gas to be 30 percent and the proportion of natural gas to be 70 percent according to a chemical reaction formula CH4+2O2＝＝CO2+2H2O、4NH3+3O2＝＝6H2O+2N2Calculating to obtain a mixed gas air-fuel ratio of 13.8 and a density of 0.73g/L, and calibrating the physicochemical characteristics of the mixed gas according to the table look-up of the low calorific value of the natural gas fuel and the low calorific value of the ammonia gas fuel, so as to start calibration torque control;
the torque control comprises the following steps: the actual torque percentage (relative to the indicated torque percentage) sent by the electronic control unit of the ammonia-natural gas dual-fuel engine is close to a true value, the indicated torque (rack torque + friction torque) is calibrated, the low calorific value of the ammonia-natural gas mixture is calibrated, and the torque coefficient is calibrated.
Further, the friction torque calibration method comprises the following steps:
(1) setting the indicated thermal efficiency and the inlet pressure of the ammonia-natural gas dual-fuel engine to be lower than 1 atmosphere according to a certain numerical coefficient;
(2) at an idle point of 600rpm, changing a torque value in a friction torque table to enable the torque of the dynamometer to be 0;
(3) the idle speed is set to different rotating speeds according to a friction torque meter, such as: repeating the step (2) at 600rpm,1200rpm and … 1900rpm to obtain the friction torque at each rotating speed, and recording the data as shown in the table 1;
TABLE 1 Friction Torque
The calibration of the thermal efficiency coefficient makes the torque of the rack equal to the net torque in the software, and the coefficient is classified according to the rotating speed and the air inlet pressure.
The torque coefficient calibration method comprises the following steps:
the torque coefficient is equal to the torque of the rotating speed point/the maximum indicated torque;
(1) selecting a rotating speed point: selecting 5 points to fully represent an external characteristic curve;
(2) operating the coordinate point at a full throttle, recording the net indicated torque, and obtaining a torque coefficient;
TABLE 2 Torque coefficients
After the steps are completed, the actual torque percentage sent by the electronic control unit of the ammonia-natural gas dual-fuel engine is close to the true value.
According to an embodiment of the invention, a linear function model is required to be established to fit the calibration of the indicated torque percentage and the throttle percentage, a function MAP is shown in fig. 4 in a value range [1,5/3] of k and kx of the linear function model g, and a torque percentage and throttle percentage MAP is calibrated according to the model in fig. 4, as shown in the example of fig. 5, and points at each rotating speed are distributed in a blue line region and a yellow line region according to the trend in fig. 4.
Further, a throttle valve calibration strategy is controlled, and the calibration steps are as follows:
(1) in a throttle valve calibration unit, the rotating speed is divided into 600rpm, 700rpm and … 1900rpm according to the difference of 100rpm, the torque percentage is calibrated according to a linear function model g (x), and the value range of x is [0,100 ];
(2) and (3) recording the position of the throttle valve in the step (1) at each rotating speed, and repeating the step (1).
Further, the responsiveness of the supercharger is controlled to obtain torque output, the torque output is calibrated and fitted according to a quadratic function model, the rotating speed is divided into 600rpm, 700rpm and … 1900rpm according to the difference of 100rpm, and the position of the throttle valve is obtained by a throttle valve calibration strategy.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (8)
1. A torque calibration method of an ammonia-natural gas dual-fuel engine is characterized by comprising the following steps of:
s1, taking the torque output of the automobile as a central target, and carrying out quadratic function model fitting calibration on the torque of the ammonia-natural gas dual-fuel engine, wherein the quadratic function model is as follows: (x) ax2+ bx, wherein a, b are not equal to 0;
s2, calibrating the physical and chemical properties of the mixture and the mixing ratio of the ammonia gas and the natural gas to obtain that the actual torque percentage sent by the electric control unit of the ammonia gas-natural gas dual-fuel engine is close to the true value;
s3, utilizing the actual torque percentage to be close to the real value, and carrying out fitting calibration on the indicated torque percentage and the throttle percentage according to a linear function model g (x) -kx, wherein k is not equal to 0, and at each rotating speed of the external characteristics;
s4, after the linear function model is obtained, under the basic calibration strategy of the throttle valve, when the rotating speed of the ammonia-natural gas dual-fuel engine is stable, the position of the throttle valve is finally obtained;
s5, according to the position of the throttle valve, starting to control the responsiveness calibration torque output value f (x) of the supercharger, establishing the relationship of a quadratic function model between the torque output value f (x) and the throttle valve x, and carrying out torque calibration, wherein f (x) is the torque output value of each rotating speed of the external characteristic, and x is the percentage of the throttle valve.
2. The method for calibrating the torque of the ammonia-natural gas dual-fuel engine as claimed in claim 1, wherein the quadratic function model f (x) ax in the step S12+ bx, where a has a value in the range of [ -1/4, -1/25 [ -1/4 [ ]]And b value range [24,45 ]]When a is-1/5 and b is 40, according to the function f (x) — (1/5) x2+40x, x takes the value [0,100]And fitting a calibrated torque MAP (MAP) and recording data.
3. The method for calibrating the torque of the ammonia-natural gas dual-fuel engine as claimed in claim 1, wherein the step S2 is performed according to the chemical reaction formula CH under the conditions that the pressure of mixed gas entering the engine is controlled to be 6bar, the temperature is controlled to be 20 ℃, the proportion of ammonia gas is 30%, and the proportion of natural gas is 70%4+2O2＝＝CO2+2H2O、4NH3+3O2＝＝6H2O+2N2Calculating to obtain the air-fuel ratio of the mixed gas of 13.8 and the density of 0.73g/L, and obtaining the physical and chemical properties of the mixed gas according to the table look-up of the low calorific value of the natural gas fuel and the low calorific value of the ammonia gas fuel;
the torque control calibration enables the actual torque percentage sent by the electronic control unit of the ammonia-natural gas dual-fuel engine to be close to the true value, the rack torque and the friction torque are calibrated, the low calorific value of the ammonia-natural gas mixture is calibrated, and the torque coefficient is calibrated.
4. The torque calibration method for the ammonia-natural gas dual-fuel engine as claimed in claim 3, wherein the friction torque calibration method comprises the following steps:
s11, setting the indicated thermal efficiency and the intake pressure of the ammonia-natural gas dual-fuel engine to be lower than 1 atmosphere according to a certain numerical coefficient;
s12, at an idling point of 600rpm, changing a torque value in the friction torque table so that the dynamometer torque becomes 0;
and S13, setting the idle speed to different rotating speeds according to the friction torque table, and repeating the step S12 to obtain the friction torque at each rotating speed.
5. The method for calibrating the torque of the ammonia-natural gas dual-fuel engine is characterized in that the calibration of the thermal efficiency coefficient enables the torque of a rack to be the net torque in software, the coefficient is classified according to the rotating speed and the air inlet pressure, and the torque coefficient is the rotating speed point torque/the maximum indicated torque; the torque coefficient calibration method comprises the following steps:
s21, selecting a rotating speed point: selecting 5 points to fully represent an external characteristic curve;
s22, operating the coordinate point at a full throttle, and recording net indicated torque;
after the steps are finished, the actual torque percentage sent by the electronic control unit of the ammonia-natural gas dual-fuel engine is close to a true value.
6. The method for calibrating the torque of the ammonia-natural gas dual-fuel engine as claimed in claim 1, wherein the calibration of the indicated torque percentage and the throttle percentage is to establish a linear function model, and a MAP of the torque percentage MAP is calibrated according to the model when g (x) is kx and k is in a value range [1,5/3 ].
7. The torque calibration method for the ammonia-natural gas dual-fuel engine as claimed in claim 1, characterized in that the calibration steps of the throttle valve are as follows:
s31, in the throttle valve calibration unit, the rotating speed is divided into 600rpm, 700rpm and … 1900rpm according to the difference of 100rpm, and the torque percentage is calibrated according to claim 6;
s32, recording the position of the throttle valve in the step S31 at each rotation speed, and repeating the step S31.
8. The method for calibrating the torque of the ammonia-natural gas dual-fuel engine as claimed in claim 1, wherein the torque output is obtained through the responsiveness of the supercharger, the torque output is calibrated and fitted according to a quadratic function model, the rotating speed is divided into 600rpm, 700rpm and … 1900rpm according to the difference of 100rpm, and the position of the throttle valve is calibrated according to claim 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210097297.2A CN114526165A (en) | 2022-01-26 | 2022-01-26 | Torque calibration method of ammonia-natural gas dual-fuel engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210097297.2A CN114526165A (en) | 2022-01-26 | 2022-01-26 | Torque calibration method of ammonia-natural gas dual-fuel engine |
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| CN112267950A (en) * | 2020-10-20 | 2021-01-26 | 东风越野车有限公司 | High-precision torque control method for hybrid diesel engine |
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| CN104595043A (en) * | 2014-12-26 | 2015-05-06 | 长城汽车股份有限公司 | Fuel oil distributing method and system of dual-fuel engine and vehicle |
| US20160222891A1 (en) * | 2015-02-04 | 2016-08-04 | General Electric Company | System and method for model based and map based throttle position derivation and monitoring |
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