Test method for fuel consumption of heavy-duty hydrogen fuelled internal combustion engine vehicle based on hydrogen balance method

Abstract

The application discloses a kind of based on hydrogen balance method's heavy hydrogen fuel internal combustion engine car fuel consumption test method, comprising: the fuel component of heavy hydrogen fuel internal combustion engine car used in accordance with predetermined standard is analyzed to obtain the hydrogen purity of fuel and fuel density;In vehicle CHTC driving cycle, the hydrogen content of exhaust emission unit mileage of CHTC driving cycle is measured and calculated;Based on the hydrogen purity of fuel obtained, fuel density and the hydrogen content of exhaust emission unit mileage, the fuel consumption of vehicle driving cycle is calculated.The application derives the fuel consumption of whole vehicle by measuring the emission mass of hydrogen component in vehicle exhaust emission, based on hydrogen element mass conservation, without damaging the original vehicle hydrogen supply system of whole vehicle, and the test safety is high, and operability is strong.

Description

Technical Field

[0001] This invention relates to the field of energy consumption testing technology for internal combustion engine vehicles, and in particular to a method for testing the fuel consumption of heavy-duty hydrogen fuel cell internal combustion engine vehicles based on the hydrogen balance method. Background Technology

[0002] During the research and development verification phase of hydrogen fuel cell internal combustion engine vehicles, fuel consumption is a crucial indicator for evaluating the energy-saving performance of these vehicles and a key parameter for consumers when choosing a vehicle. Current standards for testing vehicle fuel consumption include GB / T 19233-2020 "Test Method for Fuel Consumption of Light-Duty Vehicles," GB / T 27840-2021 "Measurement Method for Fuel Consumption of Heavy-Duty Commercial Vehicles," GB / T 29125-2012 "Test Method for Fuel Consumption of Compressed Natural Gas Vehicles," and GB / T 35178-2017 "Measurement Method for Hydrogen Consumption of Fuel Cell Electric Vehicles."

[0003] GB / T 35178-2017 provides three methods for measuring hydrogen consumption in hydrogen fuel cell electric vehicles: pressure-temperature method, mass analysis method, and flow rate method. All three methods involve external hydrogen supply. Their advantage lies in the independence of the hydrogen supply system from the vehicle system, allowing for better handling of emergencies related to hydrogen safety. However, their disadvantages include the need for vehicle manufacturers to modify the vehicle structure and the discrepancies between the measured hydrogen consumption and actual vehicle operation.

[0004] GB / T 19233-2020, GB / T 27840-2021, and GB / T 29125-2012 provide flow rate method and carbon balance method for measuring fuel consumption of light and heavy-duty gasoline / diesel vehicles and compressed natural gas vehicles, respectively. The flow rate method requires modification of the vehicle's hydrogen supply pipeline, making the testing operation more difficult. The carbon balance method, based on the conservation of carbon mass, calculates fuel consumption based on the emission mass of carbon monoxide (CO), carbon dioxide (CO2), and hydrocarbons (THC) (or methane (CH4) + non-methane hydrocarbons (NMHC)) in exhaust emissions. This method does not require modification of the existing fuel supply pipeline, is highly safe, and has strong operational feasibility, making it the most commonly used method for measuring vehicle fuel consumption currently.

[0005] However, the carbon balance method for measuring vehicle fuel consumption is based on the conservation of carbon mass and is only applicable to carbon-based fuels (gasoline, diesel, natural gas, etc.). The carbon balance method cannot be used to measure the fuel consumption of hydrogen fuel cell internal combustion engine vehicles. Summary of the Invention

[0006] The purpose of this invention is to address the problems in the prior art by providing a method for testing the fuel consumption of heavy-duty hydrogen fuel cell internal combustion engine vehicles based on the hydrogen balance method.

[0007] This invention is implemented as follows: a method for testing the fuel consumption of heavy-duty hydrogen fuel cell internal combustion engine vehicles based on the hydrogen balance method, comprising the following steps:

[0008] The hydrogen purity and fuel density of the fuel were obtained by analyzing the fuel components of heavy-duty hydrogen fuel cell internal combustion engine vehicles that meet predetermined standards.

[0009] During the CHTC driving condition of the vehicle, the hydrogen content per unit mileage of exhaust gas emissions under the CHTC driving condition is measured and calculated.

[0010] Based on the obtained hydrogen purity, fuel density, and hydrogen content per unit mileage in exhaust emissions, the fuel consumption under vehicle operating conditions is calculated using the following formula:

[0011]

[0012] In the formula, Q—fuel consumption of the test vehicle, in m³ 3 / 100km;

[0013] i—the number of trials, representing the number of trials performed, i = 1, 2, 3, 4, ..., n;

[0014] A—The purity of hydrogen in the fuel, expressed as a mole fraction or volume fraction, in %;

[0015] ρ—Fuel density under standard reference conditions of 0℃ and 101.325kPa, in kg / m³ 3 ;

[0016] —The mass percentage of hydrogen in H2 emitted from exhaust gas, in %;

[0017] —The mass percentage of hydrogen in the NH3 emitted from exhaust gas, in %;

[0018] —The mass percentage of hydrogen in exhaust gas H2O, in %;

[0019] ω 后处理反应剂_H —The mass percentage of hydrogen in the post-processing reactants of the post-processing system, in %;

[0020] —Exhaust gas emission H2 mass per unit distance, in g / km;

[0021] —The mass of NH3 emitted per unit mileage in exhaust gas, in g / km;

[0022] —Exhaust gas emission H2O per unit mileage, in g / km;

[0023] c 后处理反应剂 — The amount of post-treatment reagents introduced into the post-treatment system per unit mileage, expressed in g / km.

[0024] Calculate the standard deviation σ of the 95th percentile distribution of the combined fuel consumption results from multiple complete CHTC driving condition tests, and compare it with the difference ΔQ between the highest and lowest combined fuel consumption values ​​from the multiple test results. max For comparison, if ΔQ max If the value is less than or equal to σ, the repeatability test passes; otherwise, the repeatability test fails.

[0025]

[0026] In the formula, σ is the standard deviation of the 95th percentile distribution, g / 100km; —The arithmetic mean of the combined fuel consumption results from multiple complete CHTC driving condition tests, in g / 100km;

[0027] If the repeatability test passes, the average of the results of multiple tests is the fuel consumption and total fuel consumption of the test vehicle in each speed range of the CHTC driving condition. If the repeatability test fails, the average of the two CHTC driving condition test results with the higher total fuel consumption should be used as the fuel consumption and total fuel consumption of the test vehicle in each speed range of the CHTC driving condition.

[0028] In the CHTC driving condition of the vehicle, the exhaust gas analyzer is used to collect and record the instantaneous concentrations of unburned hydrogen (H2), water (H2O), and ammonia (NH3) throughout the entire process. At the same time, the vehicle's driving speed and mileage are recorded simultaneously, and the data sampling frequency is not less than 1Hz.

[0029] The unit mileage emission mass of exhaust gas emissions H2, H2O and NH3 is calculated by first calculating the emission mass of exhaust gas emissions H2, H2O and NH3 respectively, and then calculating the unit mileage emission mass of exhaust gas emissions H2, H2O and NH3 based on the mileage of the test vehicle.

[0030] The calculation of the emission mass per unit mileage of exhaust gas emission H2 is as follows: first, calculate the emission mass of exhaust gas emission H2 under CHTC driving conditions, and then calculate the emission mass per unit mileage of exhaust gas emission H2 under CHTC driving conditions.

[0031] The formula for calculating the H2 emission mass of exhaust gases under CHTC driving conditions is as follows:

[0032]

[0033] The formula for calculating the emission mass per unit mileage of exhaust gas H2 under CHTC driving conditions is as follows;

[0034]

[0035] In the formula, —H2 emission mass of exhaust gas under CHTC driving conditions, in g; —Density of H2 emitted from exhaust gas and exhaust density ρ e Compare, Density of H2 emissions Under standard reference conditions of 0℃ and 101.3 kPa, the value is 0.089 kg / m³. 3 Exhaust density ρ e The excess air coefficient λ = 2, dry air, 0℃, and 101.3 kPa is 1.1818 kg / m³. 3 ; —Instantaneous H2 concentration measured in exhaust gas, in ppm; —H2 concentration measured in background air, in ppm; q mew,i —Instantaneous exhaust mass flow rate, in kg / s; f—Data sampling frequency, in Hz; m—Number of measurements, representing the number of data collection records in the entire cycle; —H2 emissions per unit mileage under CHTC driving conditions, in g / km; D—Mileage of the test vehicle, in km.

[0036] The calculation of the unit mileage emission mass of NH3 in the exhaust gas is as follows: first, the emission mass of NH3 in the exhaust gas is calculated, and then the unit range emission mass of NH3 in the exhaust gas under CHTC driving conditions is calculated.

[0037] The formula for calculating the emission mass of NH3 in exhaust gas is as follows:

[0038]

[0039] The formula for calculating the unit range emission mass of NH3 in the exhaust gas under CHTC driving conditions is as follows:

[0040]

[0041] In the formula, —The mass of NH3 emitted in the exhaust gas, in grams; —Density of NH3 emitted in exhaust gas and exhaust density ρ e Compare, Density of NH3 emitted in exhaust gas Under standard reference conditions of 0℃ and 101.3 kPa, the value is 0.771 kg / m³. 3 ; —Instantaneous NH3 concentration measured in exhaust gas, in ppm; —NH3 concentration measured in background air, in ppm. —The mass of NH3 emitted per unit mileage in exhaust gas, expressed in g / km.

[0042] The calculation of the unit mileage emission mass of exhaust gas H2O is as follows: first, calculate the emission mass of exhaust gas H2O, and then calculate the unit range emission mass of exhaust gas H2O under CHTC driving conditions.

[0043] The emission mass of H2O from exhaust gas is calculated using the following formula:

[0044]

[0045] The mass of H2O emitted per unit mileage under CHTC driving conditions is calculated using the following formula:

[0046]

[0047] In the formula, —The mass of H2O emitted from exhaust gas, in grams; —Density of H2O emitted from exhaust gas and exhaust density ρ e Compared to the density of H2O emitted from exhaust gases At 0℃ and 101.3 kPa, the value is 0.600 kg / m³. 3 ; —Instantaneous H2O concentration measured in exhaust gas, in ppm; —H2O concentration measured in background air, in ppm; —H2O emissions per unit mileage under CHTC driving conditions, in g / km.

[0048] The post-treatment reaction agent includes an aqueous urea solution.

[0049] The calculation of the hydrogen introduction per unit mileage of the post-treatment system is as follows: first, calculate the consumption per unit mileage of the urea aqueous solution; then, calculate the mass percentage of hydrogen in the urea aqueous solution; and finally, calculate the hydrogen introduction per unit mileage of the urea aqueous solution under CHTC driving conditions.

[0050] Urea aqueous solution consumption per unit mileage c 尿素水溶液 Calculate using the following formula:

[0051]

[0052] In the formula, c 尿素水溶液 —Urea solution consumption per unit distance, in g / km; m 尿素水溶液 —The mass of urea solution consumed under operating conditions, in grams.

[0053] The mass percentage of hydrogen in urea aqueous solution ω 尿素水溶液_H The following formula can be used to calculate:

[0054]

[0055] In the formula, ω 尿素水溶液_H —The mass percentage of hydrogen in a urea aqueous solution, in %; ω 尿素质量百分数 —The mass percentage of urea in the urea aqueous solution, in %; —The mass percentage of hydrogen in urea CO(NH2)2, in %; —The mass percentage of hydrogen in H2O, in %;

[0056] The hydrogen introduction rate per unit mileage for urea aqueous solution under CHTC driving conditions is calculated using the following formula:

[0057]

[0058] In the formula, c 尿素水溶液_H —The amount of hydrogen introduced per unit mileage in the urea aqueous solution under driving conditions, expressed in g / km. The CHTC driving conditions vary depending on the vehicle and include CHTC-LT, CHTC-HT, CHTC-C, CHTC-TT, CHTC-D, and CHTC-B driving conditions.

[0059] Among them, the CHTC driving condition test of the vehicle was carried out on the chassis dynamometer.

[0060] This invention derives the vehicle's fuel consumption by measuring the mass of hydrogen-containing components in vehicle exhaust emissions. Based on the conservation of hydrogen mass, it does not require disruption of the vehicle's original onboard hydrogen supply system, making the experiment highly safe and easy to operate.

[0061] This invention overcomes the limitation of the traditional carbon balance method, which is only applicable to carbon-based fuels. It is applicable not only to the fuel consumption measurement of internal combustion engine vehicles using zero-carbon hydrogen fuels such as hydrogen fuel and ammonia fuel, but also to the fuel consumption measurement of internal combustion engine vehicles using traditional carbon-based fuels such as gasoline, diesel, and natural gas. This invention will provide an important basis for the development and formulation of energy consumption evaluation standards for heavy-duty hydrogen fuel cell internal combustion engine vehicles.

[0062] This invention calculates fuel consumption by measuring the hydrogen content in exhaust emissions, allowing for simultaneous testing with vehicle exhaust emissions. It maximizes the use of existing standards, employing current standard-specified driving conditions as test conditions, eliminating the need to create specific test conditions and facilitating testing. Furthermore, this invention stipulates that the fuel used for vehicle testing must comply with GB / T37244-2018 and other relevant national standards, ensuring the standardization and consistency of the tests. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the on-site setup for a test of the fuel consumption of a heavy-duty hydrogen fuel cell internal combustion engine vehicle based on the hydrogen balance method, according to an embodiment of the present invention.

[0064] Explanation of reference numerals in the attached figures:

[0065] 1- Test heavy-duty hydrogen fuel cell internal combustion engine vehicle; 2- Chassis dynamometer; 3- Exhaust piping; 4- Exhaust gas analyzer one (measuring H2); 5- Exhaust gas analyzer two (measuring NH3 and H2O); 6- Exhaust gas mass flow meter; 7- Full-flow dilution system (applicable when fuel consumption and exhaust emissions are measured simultaneously); 8- Diluted exhaust gas analyzer (measuring NO) X (Applicable when fuel consumption and exhaust emissions are measured simultaneously); 9-Road simulation cooling fan. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0067] This invention provides a test method for the fuel consumption of a heavy-duty hydrogen fuel cell internal combustion engine vehicle based on the hydrogen balance method. Based on the conservation of hydrogen mass, that is, the hydrogen content in the vehicle's intake air, fuel, and exhaust emissions remains constant, the fuel consumption of the vehicle is calculated based on the hydrogen content in the vehicle's exhaust emissions and the percentage of hydrogen in the fuel.

[0068] See Figure 1 The experimental system shown, and the experimental method for testing the fuel consumption of heavy-duty hydrogen fuel cell internal combustion engine vehicles based on the hydrogen balance method proposed in this embodiment of the invention, are implemented through the following experimental steps:

[0069] Step 1: Fuel Component Analysis

[0070] The hydrogen fuel used in the test should comply with the provisions of GB / T 37244-2018 "Hydrogen Fuel for Proton Exchange Membrane Fuel Cell Vehicles" and other relevant subsequent national standards. Before the official start of the test, samples of hydrogen fuel from the on-board hydrogen storage tank or external hydrogen storage device must be sent to an authoritative testing and inspection institution for fuel composition analysis. The test report issued by the authoritative testing and inspection institution shall provide the hydrogen purity A (mole fraction or volume fraction, %) and the density (kg / m³) of the fuel under standard reference conditions (0℃, 101.325kPa). 3 ).

[0071] Step 2: Vehicle securing and test site setup

[0072] The vehicle fuel consumption test is conducted on a chassis dynamometer. After preparing and confirming the vehicle according to relevant standards, the vehicle is driven to the chassis dynamometer and securely fixed using appropriate methods. (Refer to...) Figure 1 The test site setup is shown in the diagram. The vehicle's exhaust pipe is extended and connected to the exhaust system of the rotating test chamber. Each exhaust analyzer is correctly connected along the exhaust pipe to ensure that there are no obvious leaks in the exhaust pipe and at the connection points.

[0073] In the experimental example, exhaust gas analyzer 1 is mainly used to measure the H2 concentration in the exhaust gas, and exhaust gas analyzer 2 is mainly used to measure the H2O and NH3 concentrations in the exhaust gas. If fuel consumption and exhaust gas emission tests are conducted simultaneously, an additional full-flow dilution system 7 and a diluted exhaust gas analyzer 8 (for measuring NO) are required. X A fixed road-simulating cooling fan 9 is installed at an appropriate position directly in front of the vehicle and is turned on simultaneously during the test to cool the vehicle. If the vehicle's after-treatment system introduces an after-treatment reagent (containing hydrogen), a mass flow meter must be installed in the reagent supply system.

[0074] Step 3: Experiment Preparation

[0075] Before the formal test, the driving resistance of the test vehicle should be determined according to the requirements of Appendix C of GB / T 27840-2021, or the driving resistance value recommended in Appendix E can be directly used. The test equipment should be preheated before the test, and the exhaust gas analyzer should be calibrated using standard zero air and distance air. Before the formal test, the vehicle should be started and run for 1-2 complete driving conditions, or other methods should be used to fully preheat the vehicle and chassis dynamometer. To eliminate or reduce the influence of various hydrogen-containing components in the background air on the test measurement results, the exhaust gas analyzer should be used to collect and record the corresponding components (H2, NH3, H2O, NO) in the background air before the test. X (Applicable when fuel consumption and exhaust emission testing are conducted simultaneously) concentration.

[0076] Step 4: Selecting Driving Conditions

[0077] The selection of the driving cycle will fully incorporate the technical specifications and literature on fuel consumption of hydrogen fuel cell internal combustion engine vehicles from national, industry, and group standards, maximizing the use of existing standard resources and ensuring their continuity. To maximize the use of existing standard resources, the driving cycle used in this example is the China heavy-duty commercial vehicle test cycle (CHTC) specified in GB / T38146.2-2019 "China Automotive Driving Cycles Part 2: Heavy-Duty Commercial Vehicles".

[0078] Among them, freight trucks use the CHTC-LT (maximum design gross vehicle weight (GVW) ≤ 5500kg) or CHTC-HT (GVW > 5500kg) driving conditions; ordinary buses use the CHTC-C driving conditions; semi-trailer tractors use the CHTC-TT driving conditions; dump trucks use the CHTC-D driving conditions; and city buses use the CHTC-B driving conditions.

[0079] Step 5: Trial Run and Data Recording

[0080] The vehicle pre-test cycle, pretreatment, and immersion test shall be performed in accordance with GB / T 27840-2021. The test vehicle shall run continuously for three complete CHTC driving cycles. During operation, the use of the transmission and deceleration requirements shall be performed in accordance with GB / T 27840-2021. Between adjacent driving cycles, the vehicle and equipment shall continue to operate or be kept in a warm-up state by other means. The test data sampling frequency shall be set to 1Hz. During vehicle operation, exhaust emissions of H2, NH3, H2O, and NO shall be collected and recorded continuously. X (Applicable when fuel consumption and exhaust emissions are measured simultaneously) concentration, chassis dynamometer collects and records the driving mileage and total driving mileage (km) at each speed range of CHTC driving conditions. After each complete CHTC driving condition, the fuel consumption and combined fuel consumption at each speed range of the driving condition are recorded.

[0081] Step 6: Fuel Consumption Calculation

[0082] In the experimental example, the relative atomic masses of each element were calculated as follows: H: 1.0079; N: 14.0067; O: 15.9994; C: 12.0107.

[0083] 1. Calculation of hydrogen content per unit mileage in exhaust emissions

[0084] For heavy-duty hydrogen fuel cell internal combustion engine vehicles, the main hydrogen-containing components in exhaust emissions are unburned hydrogen (H2), water (H2O), and ammonia (NH3). Throughout the vehicle's entire driving cycle, an exhaust gas analyzer must be used to collect and record the instantaneous concentrations of these three hydrogen-containing components at least once. Simultaneously, corresponding instruments and equipment should be used to record the vehicle's speed, mileage, etc., with a data sampling frequency of no less than 1Hz.

[0085] Based on the instantaneous concentration of hydrogen-containing components measured under driving conditions and the vehicle's mileage, the emission mass per unit mileage (g / km) of each hydrogen-containing component is calculated in accordance with the relevant requirements of the current standard GB17691-2018 "Emission Limits and Measurement Methods for Pollutants from Heavy-Duty Diesel Vehicles (China VI)". Then, based on the mass percentage (%) of hydrogen element in each hydrogen-containing component, the hydrogen content per unit mileage of exhaust gas emission under driving conditions is accumulated to obtain the hydrogen content per unit mileage of exhaust gas emission under driving conditions.

[0086] (1) Calculation of hydrogen content per unit mileage in exhaust gas H2

[0087] According to the calculation requirements of Annex CA of GB 17691-2018, the emission mass of H2 in exhaust gas is... The following formula can be used to calculate:

[0088]

[0089] In the formula:

[0090] —Emission mass of H2 from exhaust gas, in grams;

[0091] — Density of H2 emitted from exhaust gas and exhaust density ρ e Compare;

[0092] The density of H2 emitted from exhaust gas The value is 0.089 kg / m under standard reference conditions (0℃, 101.3 kPa). 3 Exhaust density ρ e The excess air coefficient λ = 2, dry air, 0℃, and 101.3 kPa is 1.1818 kg / m³. 3 ,

[0093] —The instantaneous H2 concentration in the exhaust gas, in ppm, was measured by exhaust gas analyzer 1;

[0094] —The H2 concentration in the background air, in ppm, was measured by exhaust gas analyzer 1 before the test;

[0095] q mew,i—Instantaneous exhaust mass flow rate, kg / s, measured by an exhaust mass flow meter;

[0096] f—Data sampling frequency, Hz, the sampling frequency in this example is 1Hz;

[0097] m—the number of measurements, determined by the driving time and data sampling frequency, represents the number of data collection records in the entire cycle. For example, if the CHTC driving time is 1800s and the data sampling frequency is 1Hz, then the data is recorded 1800 times in 1800s, so m is 1800; if the data sampling frequency is 10Hz, then m = 18000.

[0098] Based on the vehicle mileage D (km) recorded by the chassis dynamometer, the mass of exhaust emissions H2 per unit mileage under driving conditions is calculated using the following formula. (g / km).

[0099]

[0100] Mass percentage of hydrogen in exhaust emissions H2 Therefore, the hydrogen content per unit mile of exhaust H2 emissions is 100%.

[0101] (2) Calculation of hydrogen content per unit mileage in exhaust gas NH3 emissions

[0102] According to the calculation requirements of Annex CA of GB 17691-2018, the emission mass of NH3 in the exhaust gas is... The following formula can be used to calculate:

[0103]

[0104] In the formula:

[0105] —The mass of NH3 emitted in the exhaust gas, in grams;

[0106] —Density of NH3 emitted in exhaust gas and exhaust density ρ e The density of NH3 emitted in the exhaust gas is compared to that of other gases. The value is 0.771 kg / m³ under standard reference conditions (0℃, 101.3 kPa). 3 Exhaust density ρ e Same as above.

[0107] —The instantaneous NH3 concentration in the exhaust gas, in ppm, was measured by exhaust gas analyzer 2;

[0108] —The NH3 concentration in the background air, in ppm, was measured by exhaust gas analyzer 2 before the test;

[0109] Based on the vehicle mileage D (km) recorded by the chassis dynamometer, the mass of NH3 emitted per unit mileage under driving conditions is calculated using the following formula. (g / km).

[0110]

[0111] The mass percentage of hydrogen in NH3 emitted from exhaust gas The hydrogen content per unit mile of exhaust NH3 emissions is 17.75%, therefore the hydrogen content per unit mile of exhaust NH3 emissions is

[0112] (3) Calculation of hydrogen content per unit mileage in exhaust gas H2O

[0113] According to the calculation requirements of Annex CA of GB 17691-2018, the emission mass of H2O in exhaust gas is... The following formula can be used to calculate:

[0114]

[0115] In the formula:

[0116] —Emission mass of H2O from exhaust gas, in grams;

[0117] —Density of H2O emitted from exhaust gas and exhaust density ρ e The density of H2O emitted in the exhaust gas is compared to that of other gases. At 0℃ and 101.3 kPa, the value is 0.600 kg / m³. 3 Exhaust density ρ e Same as above.

[0118] —The instantaneous H2O concentration in the exhaust gas, in ppm, was measured by exhaust gas analyzer 2;

[0119] —The H2O concentration in the background air, in ppm, was measured by exhaust gas analyzer 2 before the test;

[0120] Based on the vehicle mileage D (km) recorded by the chassis dynamometer, the mass of H2O emitted per unit mileage under driving conditions is calculated using the following formula. (g / km).

[0121]

[0122] Mass percentage of hydrogen in exhaust gas H2O The hydrogen content per unit mile of exhaust H2O is 11.19%.

[0123] 2. Calculation of hydrogen introduction per unit mileage in the aftertreatment system

[0124] In the experimental example, the vehicle exhaust aftertreatment system employs a Selective Catalytic Reduction (SCR) system, using an aqueous urea solution as the reactant, which is the primary source of introduced hydrogen. During driving conditions, the mass m of the urea solution consumed... 尿素水溶液 The urea flow rate is obtained by measuring and integrating the mass flow rate through a mass flow meter installed in the urea tank and urea supply pipeline. Based on the vehicle mileage D (km) recorded by the chassis dynamometer, the unit mileage consumption c of the urea solution under driving conditions is calculated using the following formula. 尿素水溶液 (g / km).

[0125]

[0126] In the formula:

[0127] c 尿素水溶液 —Urea aqueous solution consumption per unit mileage, g / km;

[0128] m 尿素水溶液 —The mass of urea solution consumed under driving conditions, in grams, is obtained by integrating measurements from the installed mass flow meter;

[0129] The mass percentage of hydrogen in urea aqueous solution ω 尿素水溶液_H The following formula can be used to calculate:

[0130]

[0131] In the formula:

[0132] ω 尿素水溶液_H —The mass percentage of hydrogen in a urea aqueous solution, %.

[0133] ω 尿素质量百分数 —The mass percentage of urea in the urea aqueous solution, %, is obtained from the urea aqueous solution test report;

[0134] —The mass percentage of hydrogen in urea CO(NH2)2, % is 6.71%;

[0135] —The mass percentage of hydrogen in H2O, % is 11.19%.

[0136] Based on the unit mileage consumption c of urea aqueous solution 尿素水溶液 (g / km) and the mass percentage of hydrogen in urea aqueous solution ω 尿素水溶液_H (%), the hydrogen introduction per unit mileage of the urea aqueous solution under driving conditions is calculated using the following formula. 尿素水溶液_H (g / km).

[0137]

[0138] 3. Fuel Consumption Calculation

[0139] Based on the hydrogen content per unit mile of exhaust emissions calculated above, the hydrogen introduction per unit mile of urea aqueous solution, and the hydrogen purity and density from the fuel test report, the vehicle's fuel consumption (m³) is calculated by substituting these values ​​into the following formula. 3 / 100km).

[0140]

[0141] Step 7: Determine the total fuel consumption

[0142] The standard deviation σ of the 95th percentile distribution of the combined fuel consumption results from three complete CHTC driving condition tests is calculated using the following formula, and the difference ΔQ between the highest and lowest combined fuel consumption values ​​in the three test results is calculated. max For comparison, if ΔQ max If the value is less than or equal to σ, the repeatability test passes; otherwise, the repeatability test fails.

[0143]

[0144] In the formula:

[0145] σ—Standard deviation of the 95th percentile distribution, g / 100km;

[0146] —The arithmetic mean of the combined fuel consumption results of three complete CHTC driving condition tests, in g / 100km;

[0147] If the repeatability test passes, the average of the three test results is the fuel consumption and overall fuel consumption of the test vehicle in each speed range under CHTC driving conditions. If the repeatability test fails, the average of the two complete CHTC driving condition test results with the higher overall fuel consumption among the three test results should be used as the fuel consumption and overall fuel consumption of the test vehicle in each speed range under CHTC driving conditions.

[0148] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method of testing the fuel consumption of a heavy hydrogen-fueled internal combustion engine vehicle based on the hydrogen balance method, characterized by, The method comprises the steps of: analyzing the fuel components of the heavy hydrogen fuel internal combustion engine vehicle to obtain the hydrogen purity of the fuel and the fuel density; measuring and calculating the hydrogen content per unit distance of the exhaust emission of the CHTC driving cycle; based on the obtained hydrogen purity of the fuel, the fuel density and the hydrogen content per unit distance of the exhaust emission, the fuel consumption of the CHTC driving cycle of the vehicle is calculated by using the following formula: In the formula, Q— test vehicle fuel consumption, unit m 3 / 100km; i - the number of tests, indicating the number of tests, i = 1, 2, 3, 4, …, n; A - the hydrogen purity of the fuel expressed in mole fraction or volume fraction, unit %; p - fuel density at standard reference conditions of 0°C, 101.325 kPa, in units of kg / m3 3 ; - mass percentage of hydrogen element in H2, in %; - mass percentage of hydrogen in NH3, in %; - mass percentage of hydrogen element in H2O, in %; ω 后处理反应剂_H - mass percentage of hydrogen element in the aftertreatment reaction agent of the aftertreatment system, in %; - Mass of exhaust emissions H2 per unit of distance, in g / km; - unit g / km of the exhaust emission of NH3; - Mass of exhaust emissions H2O per unit of distance, in g / km; c 后处理反应剂 - unit consumption of reagent introduced by the aftertreatment system, in g / km; Calculate the discrimination value σ of the results of multiple complete CHTC driving cycle fuel consumption tests, and the difference AQ between the highest and lowest values of fuel consumption in the multiple tests max For comparison, if AQ max ≤ σ, then the repeatability test passes; otherwise, the repeatability test fails; In the formula, - the arithmetic mean of the results of several complete CHTC driving cycle fuel consumption tests, g / 100 km; if the repeatability test passes, the average value of the multiple test results is the fuel consumption of each speed interval of the CHTC driving cycle of the test vehicle and the comprehensive fuel consumption; if the repeatability test fails, the average value of the two complete CHTC driving cycle test results with higher comprehensive fuel consumption in the multiple test results is used as the fuel consumption of each speed interval of the CHTC driving cycle of the test vehicle and the comprehensive fuel consumption.

2. The fuel consumption test method for a heavy hydrogen-fueled internal combustion engine vehicle based on the hydrogen balance method according to claim 1, characterized by, In the CHTC driving cycle of the vehicle, the instantaneous concentrations of unburned hydrogen H2, water H2O and ammonia NH3 are collected and recorded by using an exhaust analyzer, and the driving speed and distance of the vehicle are recorded synchronously, and the data sampling frequency is not less than 1 Hz.

3. The fuel consumption test method for a heavy hydrogen-fueled internal combustion engine vehicle based on the hydrogen balance method according to claim 2, characterized by, The unit distance emission mass of the exhaust emissions H2, H2O and NH3 is calculated by calculating the emission mass of the exhaust emissions H2, H2O and NH3 respectively, and then based on the distance of the test vehicle, the unit distance emission mass of the exhaust emissions H2, H2O and NH3 is calculated.

4. The fuel consumption test method for a heavy hydrogen-fueled internal combustion engine vehicle based on the hydrogen balance method according to claim 3, characterized by The calculation of the unit distance emission mass of the exhaust emission H2 is to first calculate the emission mass of the exhaust emission H2 of the CHTC driving cycle, and then calculate the unit distance emission mass of the exhaust emission H2 of the CHTC driving cycle; The calculation formula of the emission mass of the exhaust emission H2 of the CHTC driving cycle is as follows: The calculation formula of the unit distance emission mass of the exhaust emission H2 of the CHTC driving cycle is as follows; wherein — CHTC driving cycle exhaust emission of H2, unit g; — density of exhaust emission H2 and exhaust density p e ratio, density of exhaust emission H2 0.089 kg / m3at 0°C, 101.3 kPa standard reference condition 3 exhaust density p e 1.1818 kg / m3at excess air ratio λ = 2, dry air, 0°C, 101.3 kPa condition 3 ; — H2 instantaneous concentration measured in exhaust, unit ppm; — H2 concentration measured in background air, unit ppm; q mew,i — instantaneous exhaust mass flow, unit kg / s; f — data sampling frequency, unit Hz; m — measurement times, indicating the number of data collection records for the entire cycle; — CHTC driving cycle exhaust emission of H2 per unit distance, unit g / km; D — distance of test vehicle, unit km.

5. The method of claim 4, wherein the method is a method of testing the fuel consumption of a heavy hydrogen fuel internal combustion engine vehicle based on a hydrogen balance method, characterized by, The calculation of the unit distance emission mass of the exhaust emission NH3 is to first calculate the emission mass of the exhaust emission NH3, and then calculate the unit distance emission mass of the exhaust emission NH3 of the CHTC driving cycle; The calculation formula of the emission mass of the exhaust emission NH3 is as follows: The calculation formula of the unit distance emission mass of the exhaust emission NH3 of the CHTC driving cycle is as follows: wherein — the mass of NH3 emitted by the exhaust gas, in g; — the density of NH3 emitted by the exhaust gas and the exhaust gas density p e ratio, the density of NH3 emitted by the exhaust gas 0.771 kg / m3at 0°C, 101.3 kPa, standard reference conditions 3 ; — the measured instantaneous concentration of NH3 in the exhaust gas, in ppm; — the measured concentration of NH3 in the background air, in ppm, — the mass of NH3 emitted per km by the exhaust gas, in g / km.

6. The fuel consumption test method for a heavy hydrogen-fueled internal combustion engine vehicle based on the hydrogen balance method according to claim 5, characterized by The calculation of the unit distance emission mass of the exhaust emission H2O is to first calculate the emission mass of the exhaust emission H2O, and then calculate the unit distance emission mass of the exhaust emission H2O of the CHTC driving cycle; The emission mass of the exhaust emission H2O is calculated by using the following formula: The unit distance emission mass of the exhaust emission H2O of the CHTC driving cycle is calculated by using the following formula: wherein — the exhaust emission H2O emission mass in g; — the exhaust emission H2O density and exhaust density p e ratio, exhaust emission H2O density 0.600 kg / m3at 0°C, 101.3 kPa; 3 ; — the exhaust measured H2O instantaneous concentration in ppm; — the background air measured H2O concentration in ppm; — the CHTC driving cycle exhaust emission H2O emission mass per mile in g / km.

7. The method according to claim 6, wherein The post-processing reagent comprises urea aqueous solution.

8. The method according to claim 7, wherein the method is a method for testing the fuel consumption of a heavy hydrogen-fueled internal combustion engine vehicle based on the hydrogen balance method. The calculation of the unit distance hydrogen introduction amount of the post-processing system is to first calculate the unit distance consumption of the urea aqueous solution, then calculate the mass percentage of hydrogen in the urea aqueous solution, and then calculate the unit distance hydrogen introduction amount of the urea aqueous solution of the CHTC driving cycle; Unit consumption of urea solution c 尿素水溶液 is calculated with the following formula: wherein c 尿素水溶液 - unit consumption of urea aqueous solution, in g / km; m 尿素水溶液 —CHTC driving condition consumption mass of urea aqueous solution, unit g; The mass percentage ω of hydrogen in the urea aqueous solution 尿素水溶液_H This can be calculated using the formula: In the formula, ω 尿素水溶液_H — mass percentage of hydrogen element in the urea aqueous solution, unit %; ω 尿素质量百分数 - mass percentage of urea in the urea solution, in %; - mass percentage of hydrogen in urea CO(NH2)2, in %; - mass percentage of hydrogen in H2O, in %; The unit mileage hydrogen introduction amount of the urea aqueous solution in the CHTC driving cycle is calculated by the following formula: In the formula, c 尿素水溶液_H —CHTC driving condition hydrogen introduction amount per unit distance of urea aqueous solution, unit g / km.

9. The method of claim 1, wherein the method is a method of testing fuel consumption of a heavy hydrogen fuel internal combustion engine vehicle based on a hydrogen balance method. The CHTC driving cycle is set differently according to different vehicles, and the CHTC driving cycle includes CHTC-LT driving cycle, CHTC-HT driving cycle, CHTC-C driving cycle, CHTC-TT driving cycle, CHTC-D driving cycle and CHTC-B driving cycle.

10. The method of claim 1, wherein the method is a method of testing fuel consumption of a heavy hydrogen fuel internal combustion engine vehicle based on a hydrogen balance method. The test of the CHTC driving cycle of the vehicle is performed on a chassis dynamometer.

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