Method for measuring the flow rate of a hydrogen fuel cell stack coolant

Abstract

The application relates to a hydrogen fuel cell stack coolant flow measurement method. N hydrogen fuel cell stack coolant temperature data points are acquired, corresponding time information is determined, a continuous data set is formed, a count number q is set, a signal correlation formula with a single signal correlation calculation data segment interception length n is used for calculation, an array set with a preset data length M is obtained, each element size in the array set is compared, a maximum value corresponding number P is obtained, hydrogen fuel cell stack coolant flow is calculated, the count number q is updated until n+M+q=N-1 is satisfied, a hydrogen fuel cell stack coolant flow data set is obtained, and an average value is obtained. Compared with the prior art, the hydrogen fuel cell stack coolant flow can be measured without using any flow measuring instrument, and the problem that the hydrogen fuel cell stack coolant flow cannot be measured in a hydrogen fuel cell stack integrated system is solved.

Description

Technical Field

[0001] This invention relates to the field of hydrogen fuel cell technology, and in particular to a method for measuring the flow rate of coolant in a hydrogen fuel cell stack. Background Technology

[0002] Hydrogen proton exchange membrane fuel cells (HPEMFCs) are widely used in transportation, especially in buses, logistics vehicles, and heavy-duty trucks, due to their advantages such as high efficiency, zero pollution, low operating temperature, and low noise. The coolant flow rate of the hydrogen fuel cell stack significantly affects the thermal management control algorithm design of the hydrogen fuel cell cooling system, fundamentally determining the dynamic load on / off rate of the system's output power. Currently, hydrogen fuel cell systems strive for high integration. However, once the hydrogen fuel cell stack is integrated into the system, it is impossible to install flow meters to measure the actual coolant flow rate because existing flow meters are often large and have poor structural adaptability.

[0003] Therefore, it is necessary to propose a method for measuring the flow rate of the coolant in a hydrogen fuel cell stack to solve the problem that the flow rate of the coolant in a hydrogen fuel cell stack cannot be measured using instruments and equipment. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art by providing a method for measuring the flow rate of the coolant in a hydrogen fuel cell stack. By processing the temperature and time data acquired by the sensor, the flow rate of the coolant in the hydrogen fuel cell stack can be measured without using any flow measurement instrument.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] This invention provides a method for measuring the flow rate of coolant in a hydrogen fuel cell stack, comprising the following steps:

[0007] S1: Obtain data points of N hydrogen fuel cell stack coolant inlet and outlet temperatures and determine the corresponding time information to form a continuous dataset;

[0008] S2: Set the count number q, and calculate the data segment with single signal correlation in the dataset in S1 according to the signal correlation formula with length n, to obtain an array set with a preset data length M.

[0009] S3: Compare the size of each element in the array set in S2 to obtain the index P corresponding to the maximum value of the array;

[0010] S4: Calculate the coolant flow rate of the hydrogen fuel cell stack;

[0011] S5: Update the count number q in S2, repeat S2-S5 until n+M+q=N-1 is satisfied, and obtain the dataset of hydrogen fuel cell stack coolant flow rate. Take the average value of the hydrogen fuel cell stack coolant flow rate dataset, which is the hydrogen fuel cell stack coolant flow rate.

[0012] Furthermore, in S1, the data for the inlet and outlet temperatures of the hydrogen fuel cell stack coolant come from the coolant inlet temperature sensor and the outlet temperature sensor, respectively.

[0013] The temperature and time correspondence obtained by the inlet temperature sensor is as follows: Tin[t|1], Tin[t|2]…Tin[t|N-1], Tin[t|N], where N is the total number of data points and t is the time interval;

[0014] The temperature and time correspondence obtained by the outlet temperature sensor is: Tout[t|1], Tout[t|2]…Tout[t|N-1], Tout[t|N], where N is the total number of data points and t is the time interval.

[0015] Further, in S2, the signal correlation formula is: X[k|q]=Tin[t|1+q]*Tout[t|1+k+q]+…+Tin[t|n+q]*Tout[t|n+k+q];

[0016] Where q is the counter number, initially set to 0 and q is a non-negative integer during the first execution; M is the data length; t is the time interval; k is the array element index number in the current array set, 0≤k≤M-1 and satisfying n+M+1≤N; n is the truncation length of the data segment extracted from the continuous dataset for a single signal correlation calculation.

[0017] Further, in S2, the array set is X[0|q], X[1|q], X[2|q]…X[M-1|q];

[0018] Where q is the counter number, which is set to 0 and is a non-negative integer during the first execution; M is the data length.

[0019] Furthermore, in S2, when the inlet temperature of the hydrogen fuel cell stack fluctuates frequently, the data length M is reduced within a preset range and the data acquisition time interval t is shortened within a preset range.

[0020] When the inlet temperature of the hydrogen fuel cell stack fluctuates slowly, the data length M is set to be longer within a preset range, and the data acquisition time interval t is set to be longer within a preset range.

[0021] Further, in S2, the data length M is specifically the maximum allowable number of elements in the current array set {X[0|q],…X[M - 1|q]}.

[0022] Further, in S3, when i < P, X[P|q] > X[i|q]; when i > P, X[i|q] < X[P|q];

[0023] where i is the index number of the array element in the current array set, 0 ≤ i ≤ M - 1, M is the data length; P is the number corresponding to the maximum value of the array.

[0024] Further, in S4, according to the data segment Tin[t|q]…Tin[t|n + q], the formula for calculating the corresponding coolant flow rate of the hydrogen fuel cell stack is:

[0025] Q stk [t|q] = V stk / ([t|P + q] - [t|q])

[0026] where V stk is the volume of the coolant cavity of the hydrogen fuel cell stack; P is the number corresponding to the maximum value of the array; q is the counting number.

[0027] Further, the data segment Tin[t|q]…Tin[t|n + q] is a data segment intercepted from the continuous dataset for a single signal correlation calculation, and the Q stk [t|q] corresponds one-to-one with the data segment Tin[t|q]…Tin[t|n + q];

[0028] where n is the interception length of the data segment intercepted from the continuous dataset for a single signal correlation calculation; q is the counting number, and q = 0 is set for the first execution and q is a non-negative integer.

[0029] Further, in S5, the specific process is: update the counting number q to make q automatically increment by 1, and take the average value of the dataset Qstk[t|1], Qstk[t|2]…Qstk[t|N - 1 - n - M] of the coolant flow rate of the hydrogen fuel cell stack, which is the coolant flow rate of the hydrogen fuel cell stack.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] By processing the temperature and time data obtained by the sensor, the present invention can measure the coolant flow rate of the hydrogen fuel cell stack without using any flow measurement instruments, and solve the problem that the coolant flow rate of the hydrogen fuel cell stack in the system integrated with the hydrogen fuel cell stack is unmeasurable. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of a typical hydrogen fuel cell stack cooling system in Example 1;

[0033] Figure 2 This is a schematic diagram of a method for measuring the flow rate of coolant in a hydrogen fuel cell stack.

[0034] Figure 1 Explanation of the markings in the text:

[0035] 1-Water tank, 2-Control module, 3-Fan radiator, 4-Electronic thermostat, 5-Inlet temperature sensor, 6-Fuel cell stack coolant chamber, 7-Outlet temperature sensor, 8-Water pump. Detailed Implementation

[0036] The following examples illustrate specific implementations of the present invention. These examples are carried out based on the solution described in the present invention, and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following examples.

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0038] Example 1

[0039] The hydrogen fuel cell stack cooling system includes a fuel cell stack coolant chamber 6, a water pump 8, a fan-type radiator 3, an electronic thermostat 4, a water tank 1, an inlet temperature sensor 5, an outlet temperature sensor 7, a control module 2, and piping, such as... Figure 1 As shown.

[0040] The fuel cell stack coolant chamber 6 is a collection of coolant flow chambers consisting of a single-plate coolant chamber for the fuel cell, a coolant supply manifold for the stack, and a coolant discharge manifold for the stack. The water pump 8 performs work on the coolant, driving its circulation within the cooling system.

[0041] The electronic thermostat 4 is an electronically adjustable thermostat consisting of two coolant inlets and one coolant outlet. It is used to regulate the first flow resistance generated when coolant enters from the first coolant inlet and finally flows out from the coolant outlet, and simultaneously regulates the flow resistance generated when coolant enters from the second coolant inlet and finally flows out from the coolant outlet. When the first flow resistance increases, the second flow resistance will necessarily decrease, and when the first flow resistance decreases, the second flow resistance will necessarily increase.

[0042] The fan-type radiator 3 consists of two parts: a fan and a radiator. When the coolant flows through the radiator, the fan rotates and drives the ambient air to flow through the gaps in the radiator, so that the coolant and the ambient air exchange heat through the radiator, thereby changing the temperature of the coolant.

[0043] Water tank 1 is used to store coolant. The bottom of the water tank is connected to the water pump inlet through a pipeline. Under the action of gravity, the coolant establishes an absolute pressure reference point at the water pump inlet.

[0044] An inlet temperature sensor is installed at the inlet of the fuel cell stack coolant chamber 6 to measure the temperature of the coolant entering the chamber. An outlet temperature sensor is installed at the outlet of the fuel cell stack coolant chamber 6 to measure the temperature of the coolant leaving the chamber.

[0045] Control module 2 is used to collect temperature and time data from the inlet temperature sensor and the outlet temperature sensor. Control module 2 is used to actively regulate the water pump speed, the opening of the electronic thermostat, and the fan speed of the fan-type radiator to ensure that the fuel cell stack temperature meets the target requirements.

[0046] When the hydrogen fuel cell stack cooling system is operating, the coolant from the fuel cell stack coolant chamber outlet enters the water pump inlet via a pipeline. After being pressurized by the water pump, the coolant flows out from the pump outlet and splits into two paths. One path flows through a pipeline into a fan-type radiator to exchange heat with the ambient air before re-entering the first coolant inlet of the electronic thermostat. The other path flows directly into the second coolant inlet of the electronic thermostat. The coolant entering the first and second coolant inlets of the electronic thermostat flows out through the electronic thermostat coolant outlet and mixes thoroughly. The mixed coolant then re-enters the fuel cell stack coolant chamber inlet, thus achieving coolant circulation. Exhaust pipes are installed at locations in the hydrogen fuel cell stack cooling system where gas tends to accumulate. The other end of the exhaust pipe is connected to the water tank, allowing air bubbles to be smoothly discharged into the water tank, thereby ensuring relatively stable pressure throughout the hydrogen fuel cell stack cooling system.

[0047] Based on the above principles, this embodiment provides a method for measuring the flow rate of coolant in a hydrogen fuel cell stack, such as... Figure 2 As shown, it includes the following steps:

[0048] S1: Obtain the temperature data at the coolant inlet and outlet of the hydrogen fuel cell stack and determine the corresponding time information to form a continuous data set. Among them, the temperature and time correspondence obtained by the inlet temperature sensor are: Tin[t|1], Tin[t|2]…Tin[t|N - 1], Tin[t|N], where N is the total number of data points; the temperature and time correspondence obtained by the outlet temperature sensor are: Tout[t|1], Tout[t|2]…Tout[t|N - 1], Tout[t|N], where N is the total number of data points. The number of data points N must be sufficient.

[0049] S2: When initially executing step S2 for the first time, set the counting number q = 0 and q must be a non - negative integer. According to the signal correlation calculation formula X[k|q] = Tin[t|1 + q]*Tout[t|1 + k + q]+…+Tin[t|n + q]*Tout[t|n + k + q], calculate and obtain the array sets X[0|q], X[1|q], X[2|q]…X[M - 1|q] respectively. Among them, n is the length of the data segment intercepted from the continuous data set for a single signal correlation calculation, such as Tin[t|1 + q]…Tin[t|n + q] and Tout[t|1 + k + q]…Tout[t|n + k + q]; k is the index number of the array element in the current array set {X[0|q],…X[M - 1|q]}, 0 ≤ k ≤ M - 1 and satisfies n + M + 1 ≤ N. Among them, the data length M and the data acquisition time interval t can be determined according to the actual situation of the coolant. The data length M is specifically the maximum allowable number of elements in the current array set {X[0|q],…X[M - 1|q]}.

[0050] When the inlet temperature of the hydrogen fuel cell stack fluctuates relatively frequently, the data length M can be appropriately reduced within the preset range, and the data acquisition time interval should be appropriately shortened within the preset range; when the inlet temperature of the hydrogen fuel cell stack fluctuates relatively slowly, the data length M can be appropriately increased within the preset range, and the data acquisition time interval should be appropriately lengthened within the preset range.

[0051] S3: Compare the sizes of the elements in the array sets X[0|q], X[1|q], X[2|q]…X[M - 1|q] in S2 and obtain the number P corresponding to the maximum value of the array. Among them, when i < P, X[P|q]>X[i|q]; when i > P, X[i|q]<X[P|q], where i is the index number of the array element in the current array set {X[0|q],…X[M - 1|q]}, 0 ≤ i ≤ M - 1.

[0052] S4: Calculate the coolant flow rate Q of the hydrogen fuel cell stack stk [t|q] = V stk / ([t|P+q]-[t|q]). Where V stk It refers to the volume of the coolant chamber in the hydrogen fuel cell stack.

[0053] S5: Update q so that it automatically increments by 1. Execute S2, S3, S4, and S5 again to obtain a new Qstk[t|q]. Repeat this process until n+M+q=N-1. Finally, obtain Qstk[t|1], Qstk[t|2]…Qstk[t|N-1-nM]. Take the average value of Qstk[t|1] to Qstk[t|N-1-nM], which is the coolant flow rate of the hydrogen fuel cell stack. To improve calculation accuracy, N-1-nM must be large enough. Qstk[t|q] corresponds one-to-one with data segments Tin[t|q]…Tin[t|n+q].

[0054] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for measuring the flow rate of coolant in a hydrogen fuel cell stack, characterized in that, It includes the following steps: S1: Obtain data points of the coolant inlet and outlet temperatures of N hydrogen fuel cell stacks and determine the corresponding time information to form a continuous data set; S2: Set a counting number q. For the data set in S1, calculate data segments according to the signal correlation formula with a single - time signal correlation calculation and an intercepted length n, and obtain an array set with a preset data length M; S3: Compare the sizes of each element in the array set in S2 to obtain the number P corresponding to the maximum value of the array; S4: Calculate the coolant flow rate of the hydrogen fuel cell stack; S5: Update the counting number q in S2, repeat S2 - S5 until n + M+q = N - 1 is satisfied, obtain a data set of the coolant flow rate of the hydrogen fuel cell stack, and take the average value of the data set of the coolant flow rate of the hydrogen fuel cell stack, which is the coolant flow rate of the hydrogen fuel cell stack; In S1, the data of the coolant inlet and outlet temperatures of the hydrogen fuel cell stack are respectively from a coolant inlet temperature sensor and an outlet temperature sensor; The corresponding relationship between the temperature and time obtained by the inlet temperature sensor is: Tin[t|1], Tin[t|2]…Tin[t|N - 1], Tin[t|N], where N is the total number of data points and t is the time interval; The corresponding relationship between the temperature and time obtained by the outlet temperature sensor is: Tout[t|1], Tout[t|2]…Tout[t|N - 1], Tout[t|N], where N is the total number of data points and t is the time interval; In S2, the signal correlation formula is: X[k|q]=Tin[t|1 + q]*Tout[t|1 + k + q]+…+Tin[t|n + q]*Tout[t|n + k + q]; Where q is the counting number, q = 0 is set at the initial first execution and q is a non - negative integer; M is the data length; t is the time interval; k is the index number of the array element in the current array set, 0≤k≤M - 1 and n + M + 1≤N; n is the intercepted length of the data segment for a single - time signal correlation calculation from the continuous data set; In S4, according to the data segment Tin[t|q]…Tin[t|n + q], the formula for calculating the corresponding coolant flow rate of the hydrogen fuel cell stack is: Q stk [t|q]=V stk / ([t|P+q]-[t|q]) Among them, V stk is the volume of the coolant chamber of the hydrogen fuel cell stack; P is the number corresponding to the maximum value of the array; q is the count number, which is initially set to 0 and is a non-negative integer during the first execution.

2. The method for measuring the flow rate of coolant in a hydrogen fuel cell stack according to claim 1, characterized in that, In S2, the array set is X[0|q], X[1|q], X[2|q]…X[M - 1|q]; Where q is the counting number, q = 0 is set at the initial first execution and q is a non - negative integer; M is the data length.

3. The method for measuring the flow rate of coolant in a hydrogen fuel cell stack according to claim 1, characterized in that, In S2, when the inlet temperature of the hydrogen fuel cell stack fluctuates frequently, the data length M is taken to be less within a preset range and the data acquisition time interval t is taken to be short within a preset range; When the inlet temperature of the hydrogen fuel cell stack fluctuates slowly, the data length M is taken to be more within a preset range and the data acquisition time interval t is taken to be long within a preset range.

4. The method for measuring the flow rate of coolant in a hydrogen fuel cell stack according to claim 1, characterized in that, In S2, the data length M is specifically the maximum allowable number of elements in the current array set {X[0|q],…X[M - 1|q]}.

5. The method for measuring the flow rate of coolant in a hydrogen fuel cell stack according to claim 1, characterized in that, In S3, when i<P, X[P|q]>X[i|q]; when i>P, X[i|q]<X[P|q]; Where i is the index number of the array element in the current array set, 0≤i≤M-1, M is the data length; P is the number corresponding to the maximum value of the array.

6. The method for measuring the flow rate of coolant in a hydrogen fuel cell stack according to claim 1, characterized in that, The data segment Tin[t|q]…Tin[t|n+q] is a single data segment extracted from a continuous dataset for signal correlation calculation. Q stk [t|q] corresponds one-to-one with the data segment Tin[t|q]…Tin[t|n+q]; Where n is the length of the data segment extracted from the continuous dataset for a single signal correlation calculation; q is the counter number, which is initially set to 0 and is a non-negative integer during the first execution.

7. The method for measuring the flow rate of coolant in a hydrogen fuel cell stack according to claim 1, characterized in that, In S5, the specific process is as follows: update the count number q so that q is automatically incremented by 1, and take the average value of the dataset Qstk[t|1], Qstk[t|2]...Qstk[t|N-1-nM] of the hydrogen fuel cell stack coolant flow rate, which is the hydrogen fuel cell stack coolant flow rate.

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