Method and device for obtaining the lowest fuel consumption speed of a diesel generator set

Abstract

The present application belongs to diesel generator technical field, disclose a kind of method for obtaining the lowest fuel consumption rate speed of diesel generating set, can keep the stability of speed setting value under the condition that electric load fluctuates randomly, prevent the decline of oil-saving ability, greatly improve the stability of diesel generating set system, first, in the output load range of diesel generating set, load sliding interval is set, secondly, the load sliding interval is incrementally moved based on the real-time output load of diesel generating set, the lowest fuel consumption rate speed corresponding to each load sliding interval is established, and the lowest fuel consumption rate speed curve of the instantaneous output load of diesel generating set matched with the lowest fuel consumption speed is matched.The present application also discloses a kind of device for obtaining the lowest fuel consumption rate speed of diesel generating set for implementing the above-mentioned method for obtaining the lowest fuel consumption rate speed of diesel generating set, including power sensor, low-pass filter, memory and processor.

Description

Technical Field

[0001] This invention belongs to the field of diesel generator technology, specifically relating to a method and apparatus for obtaining the lowest fuel consumption rate speed of a diesel generator set. Background Technology

[0002] Marine variable-speed diesel generator sets can adjust the given speed of the generator diesel engine according to changes in the ship's electrical load, so that the diesel engine is always at the lowest fuel consumption rate speed with high efficiency and low fuel consumption. However, during the ship's navigation, the ship's electrical load is prone to large fluctuations. For example, in the event of a storm, in order to avoid deviating from the course, it is necessary to increase the electrical load of the active electric propulsion device. This stepless speed adjustment method will cause the diesel engine speed to be adjusted too frequently, making it difficult for the system to maintain stability for a long time, thus reducing the stability and reliability of the unit's operation.

[0003] Currently, in order to solve the above problems, relevant researchers have proposed a stepped speed regulation strategy. This type of strategy obtains the optimal speed within a set power range through a certain optimization method. In the optimization method, it is assumed that the actual power is evenly distributed in the set range. The method of using the power range to correspond to the lowest fuel consumption speed reduces fuel consumption to a certain extent and enables the system to remain relatively stable.

[0004] However, in actual navigation, the actual electrical load is not evenly distributed across the power range, which cannot fully utilize the fuel-saving performance of the speed change method. In particular, the fuel-saving effect is worst near the boundary of the range, and it still leads to frequent changes in the set speed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and apparatus for obtaining the lowest fuel consumption rate speed of a diesel generator set. This method can maintain the stability of the speed set value under random fluctuations in electrical load, avoid the decrease in fuel-saving capability due to large speed fluctuations, and greatly improve the stability of the diesel generator set system.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method and apparatus for obtaining the minimum fuel consumption rate speed of a diesel generator set, wherein within the output load range of the diesel generator set, by setting a load sliding interval, the load sliding interval is incrementally moved based on the real-time output load of the diesel generator set, and a minimum fuel consumption rate speed curve of the diesel generator set corresponding to the minimum fuel consumption rate speed of each load sliding interval is established, which matches the minimum fuel consumption speed of the diesel generator set with the real-time output load.

[0008] Preferably, the specific optimization steps to obtain the speed with the lowest fuel consumption rate are as follows:

[0009] S1. Set parameters such as load sliding interval width and diesel engine output load range;

[0010] S2. Establish a model for an optimization algorithm to calculate the engine speed with the lowest fuel consumption rate;

[0011] S3. Based on the optimization algorithm method for calculating the minimum fuel consumption rate speed, the model and the load slip interval width and diesel engine are used to obtain the minimum fuel consumption rate speed corresponding to the load slip interval;

[0012] S4. Save the load slip range and the corresponding minimum fuel consumption rate speed calculated this time. Then compare the extreme value of the output load range of the generator set with the extreme value of the load slip range. If they are equal, obtain the minimum fuel consumption rate speed curve. Otherwise, move the load slip range increment by 1 unit and proceed to step S3.

[0013] Preferably, the maximum width of the load sliding interval is equal to 30% of the total output load range of the diesel generator set.

[0014] Preferably, the real-time output load of the diesel generator set is the output load value of the diesel generator set at the midpoint of the load sliding range.

[0015] Preferably, when the absolute value of the change in the real-time output load of the diesel generator set is greater than or equal to half the width of the load sliding range, the load sliding range is adjusted first, and then a new minimum fuel consumption rate speed is obtained based on the minimum fuel consumption rate speed curve.

[0016] Preferably, the optimization algorithm for the lowest fuel consumption rate speed adopts a swarm intelligence optimization algorithm.

[0017] Preferably, the swarm intelligence optimization algorithm can be either particle swarm optimization or gray wolf optimization.

[0018] An apparatus for obtaining the minimum fuel consumption rate speed of a diesel generator set includes: a power sensor, a processor, and a memory; the power sensor is used to obtain the output power of the diesel generator set in real time; the memory stores a processing program and a predetermined load sliding range, and when the processor executes the processing program, the electronic device for obtaining the minimum fuel consumption rate speed curve of the diesel generator set is used to implement the method for establishing the minimum fuel consumption rate speed curve of the diesel generator set.

[0019] Preferably, it further includes a filter, which filters the output power of the diesel generator set obtained from the power sensor.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. The present invention uses the load sliding range to optimize the minimum fuel consumption rate speed, which can obtain a continuously changing minimum fuel consumption rate speed. Different sliding range widths can produce different minimum fuel consumption rate speed curves. Therefore, the present invention can maintain the stability of the speed very well.

[0022] 2. The sliding range speed adjustment method used in this invention does not require speed setting according to electrical load levels. Therefore, this invention can achieve the best fuel-saving effect under any electrical load, and the overall fuel-saving effect is better than the continuously changing speed setting method.

[0023] 3. Under conditions of random fluctuations in electrical load, the sliding interval method has a certain filtering function. Therefore, this invention avoids possible speed fluctuations and a decrease in fuel-saving capability, and can maintain the stability of the diesel generator set system.

[0024] 4. The width of the sliding interval can be adjusted, therefore, the present invention can better adapt to the fluctuations of actual power load. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the load sliding range according to an embodiment of the present invention;

[0026] Figure 2 This is a flowchart illustrating the minimum fuel consumption rate speed optimization based on the load slip range, as shown in an embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram showing the minimum fuel consumption rate speed corresponding to different load sliding range widths in an embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram of a variable speed diesel generator set speed optimization and adjustment device according to an embodiment of the present invention.

[0029] In the diagram: T1, power signal; T2, current actual load value; T3, load range; T4, sliding range width; 1, power sensor; 2, low-pass filter; 3, memory; 4, processor. Detailed Implementation

[0030] To make the technical means, creative features, objectives and effects of the present invention easier to understand, the following embodiments, in conjunction with the accompanying drawings, specifically describe a method and apparatus for obtaining the lowest fuel consumption rate speed of a diesel generator set. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0031] like Figure 1The diagram shown is a schematic of the load sliding interval in this embodiment. Within the output load range of the diesel generator set, the load sliding interval is incrementally moved based on the real-time output load of the diesel generator set, and a minimum fuel consumption rate speed curve of the diesel generator set's instantaneous output load is established, which matches the minimum fuel consumption rate speed of each load sliding interval with the minimum fuel consumption speed.

[0032] Specifically, within the output load range of the diesel generator set, if the load slip interval increases by 1% of the rated value, then the minimum fuel consumption rate speed of the i-th interval can be expressed as:

[0033]

[0034] stn e ≤n max

[0035] n e ≥n min

[0036] n e ≥g(P m×i (1)

[0037] In the formula:

[0038] BSFC stands for fuel consumption rate;

[0039] m represents the number of integer loads (power percentages) contained within the power range;

[0040] f(n e ,P j ) represents the fuel consumption rate function;

[0041] n e Indicates the diesel engine speed;

[0042] n max Indicates the maximum speed of the diesel engine;

[0043] n min Indicates the minimum engine speed of the diesel engine;

[0044] g(P m×i ) represents the limiting function between speed and power;

[0045] P j This indicates the integer loads (power percentages) contained in this range;

[0046] r j This indicates the proportion of the load across the entire load range;

[0047] Where r j This can be expressed as:

[0048]

[0049] In the above formulas, formula (1) calculates the minimum fuel consumption rate speed corresponding to a certain load within a certain load sliding range by weighted averaging the proportion of each integer load in the total load of the entire range. Formula (2) is used to calculate the proportion of each integer load in the load range, with the denominator being the sum of all integer loads in the range and the numerator being the integer load value. For example, in the load (%) range [15, 20), the integer load values ​​included are 15, 16, 17, 18, and 19, and the sum of all integer load values ​​is 85. Thus, the proportion of each integer load in the entire load range can be obtained. Therefore, the optimal speed is obtained by weighted averaging of loads, reflecting the decisive role of load (power) in determining the minimum fuel consumption rate speed.

[0050] In this embodiment, during use, the real-time output load of the diesel generator set is the load value at the midpoint of the sliding range. For example, if the real-time output load of the diesel generator set is 17%, its corresponding optimal speed is the optimal speed corresponding to the load sliding range [15, 20); while the optimal speed corresponding to the real-time output load of the diesel generator set is 18%, it is the optimal speed corresponding to the load sliding range [16, 21). When the real-time output load of the diesel generator set is less than or equal to the minimum load, the load value corresponding to the minimum load is used; when the actual load is slightly greater than the minimum load, but has not exceeded one load sliding range, for example, if the minimum load limit is 10% and the current load is 10%, the actual corresponding speed is the load sliding range [10, 13); if the current load is 11%, the corresponding load sliding range is [10, 14), and so on. When near the upper limit of the load sliding range, a similar method is used.

[0051] Fuel consumption rate function f(n) e ,P j The fuel consumption rate can be obtained by fitting experimental data or by calculating it using a future diesel engine model. To ensure the accuracy of the fuel consumption rate calculation, it can be obtained by fitting experimental data, for example, using a neural network.

[0052] like Figure 2 The diagram shown is a flowchart of the minimum fuel consumption rate speed optimization based on the load slip range in this embodiment. The specific steps are as follows:

[0053] S1. Set parameters such as load sliding interval width and diesel engine output load range;

[0054] S2. Establish a model for an optimization algorithm to calculate the engine speed with the lowest fuel consumption rate;

[0055] S3. Based on the optimization algorithm method for calculating the minimum fuel consumption rate speed, the model and the load sliding interval width and the diesel engine are used to obtain the minimum fuel consumption rate speed corresponding to the load sliding interval;

[0056] S4. Save the load slip range and the corresponding minimum fuel consumption rate speed calculated this time. Then compare the extreme value of the output load range of the generator set with the extreme value of the load slip range. If they are equal, obtain the minimum fuel consumption rate speed curve. Otherwise, move the load slip range increment by 1 unit and proceed to step S3.

[0057] Specifically, the parameters set in step S1 include the load sliding interval width, the diesel generator set speed range, and the diesel engine output load range. In step S2, a model of an optimization algorithm for calculating the minimum fuel consumption rate speed is established. The optimization algorithm can be a swarm intelligence optimization method, such as particle swarm optimization or gray wolf algorithm, or other algorithms.

[0058] like Figure 3 The diagram shows the minimum fuel consumption rate speed corresponding to different load sliding range widths in this embodiment. The width of the load sliding range can be set according to the real-time output load and characteristics of the diesel generator set. In this embodiment, Figure 3 The solid line represents the optimal speed curve at each load point obtained by using load changes. The curves corresponding to the intervals of 5%, 10%, 15%, and 20% are the minimum optimized speed curves obtained when the load sliding intervals are 5, 10, 15, and 20, respectively. Figure 3 As can be seen, the difference between using a 5% load sliding range and using continuous variation is small. The larger the range length, the greater the difference between the optimal speeds.

[0059] like Figure 4 The diagram shows a speed optimization and adjustment device for a variable-speed diesel generator set in this embodiment. First, the power sensor 1 acquires the power signal T1 and converts it into a power value. The low-pass filter 2 filters the power value and converts it into the current actual load value T2. After the current actual load value T2 is input into the memory 3, the memory 3 calculates the load interval T3 corresponding to the current actual load value T2 based on the load sliding interval width T4 setting. After the load interval T3 corresponding to the current actual load value T2 is input into the processor 4, the processor 4 selects the corresponding minimum fuel consumption rate speed curve based on the set load sliding interval width T4, and obtains the minimum fuel consumption rate speed based on the input load interval. The obtained minimum fuel consumption rate speed value is used as the set speed input value of the diesel engine governor to adjust the actual operating speed of the diesel engine.

[0060] Specifically, memory 3 first converts the current input power value into a load value:

[0061]

[0062] In equation (3), L i The current electrical load should be an integer value, expressed as a decimal; P is the current power; P e This is the rated power.

[0063] Then calculate the difference between the output load and the current load. If the absolute value of the difference is greater than or equal to half the width of the sliding interval, update the output load; if the absolute value of the difference is less than half the width of the sliding interval, keep the output load range unchanged, as shown in the following formula:

[0064]

[0065] In equation (4), L i Current electrical load; L o The output load range is represented by an integer load value that corresponds to that range; Δ is the width of the sliding window.

[0066] The above formula actually has a filtering function, which improves the stability of the output load range.

[0067] The above embodiments are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Various modifications or variations that can be made by those skilled in the art without creative effort within the scope of the appended claims are still within the scope of protection of this patent.

Claims

1. A method for obtaining the lowest fuel consumption rate speed of a diesel generator set, characterized in that, Within the output load range of the diesel generator set, a load sliding interval is set. Based on the real-time output load of the diesel generator set, the load sliding interval is incrementally shifted to establish a minimum fuel consumption rate speed curve for each load sliding interval, matching the minimum fuel consumption rate speed with the instantaneous output load of the diesel generator set. The real-time output load of the diesel generator set is the output load value of the diesel generator set at the midpoint of the load sliding range. When the absolute value of the change in the real-time output load of the diesel generator set is greater than or equal to half the width of the load sliding range, the load sliding range is adjusted first, and then a new minimum fuel consumption rate speed is obtained based on the minimum fuel consumption rate speed curve.

2. The method for obtaining the lowest fuel consumption rate speed of a diesel generator set as described in claim 1, characterized in that, The specific optimization steps to obtain the engine speed with the lowest fuel consumption rate are as follows: S1. Set parameters such as load sliding interval width and diesel engine output load range; S2. Establish a model for an optimization algorithm to calculate the engine speed with the lowest fuel consumption rate; S3. Based on the optimization algorithm for calculating the minimum fuel consumption rate speed, the model and the load slip interval width and diesel engine are used to obtain the minimum fuel consumption rate speed corresponding to the load slip interval; S4. Save the load slip range and the corresponding minimum fuel consumption rate speed calculated this time. Then compare the extreme value of the output load range of the generator set with the extreme value of the load slip range. If they are equal, obtain the minimum fuel consumption rate speed curve. Otherwise, move the load slip range increment by 1 unit and proceed to step S3.

3. The method for obtaining the lowest fuel consumption rate speed of a diesel generator set according to claim 1, characterized in that: The maximum width of the load sliding interval is equal to 30% of the total output load range of the diesel generator set.

4. The method for obtaining the lowest fuel consumption rate speed of a diesel generator set according to claim 2, characterized in that: The optimization algorithm for the lowest fuel consumption rate speed adopts a swarm intelligence optimization algorithm.

5. The method for obtaining the lowest fuel consumption rate speed of a diesel generator set according to claim 4, Its features are: The swarm intelligence optimization method described above can employ particle swarm optimization and gray wolf optimization algorithms.

6. A device for obtaining the lowest fuel consumption rate speed of a diesel generator set, characterized in that, include: Power sensor, processor, and memory; The power sensor is used to acquire the output power of the diesel generator set in real time. The memory stores a processing program and a predetermined load sliding range, which is the load sliding range as described in any one of claims 1-5. When the processor executes the processing program, the electronic device for obtaining the minimum fuel consumption rate speed curve of the diesel generator set is used to implement the method for obtaining the minimum fuel consumption rate speed of the diesel generator set as described in any one of claims 1-5.

7. The apparatus for obtaining the lowest fuel consumption rate speed of a diesel generator set according to claim 6, characterized in that, Also includes: A filter is used to filter the output power of the diesel generator set obtained from the power sensor.

Images