A detection method for electric quantity balance of a hybrid forklift truck

Abstract

This invention discloses a method for detecting the battery balance of a hybrid forklift. First, the forklift's travel distance and speed are set under various working conditions, including both unloaded and fully loaded states. The battery capacity V0 of the forklift's lithium battery pack is adjusted so that V0 is 50% of the total battery capacity V. The forklift is then started and operated under unloaded conditions, performing straight-line, turning, bumpy, uphill, and downhill maneuvers, and under full load, performing lifting and straight-line operations. After completion, the forklift is stopped and the battery capacity V1 of the lithium battery pack is detected. If 55%V > V1 > 50%V, the battery is balanced. If V1 < 50%V, the battery is depleted, requiring an increase in generator power and adjustment of the lithium battery pack capacity. If V1 > 55%V, the generator capacity is too strong, requiring a decrease in generator power and adjustment of the lithium battery pack capacity. This method for detecting the battery balance of a hybrid forklift solves the problem of battery depletion caused by complex changes in the power output of hybrid forklifts, which affects the normal operation of the forklift.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of forklifts, in particular to a detection method for electric quantity balance of a hybrid forklift. BACKGROUND

[0002] The electric quantity balance of a vehicle refers to the mutual restriction relationship between the power generation and consumption of a generator, a storage battery and other various electric devices of the vehicle. The input and output electric quantity between the vehicle electrical system, including the storage battery, the alternator and various vehicle electric devices, is tested to determine whether the balance is achieved, which determines the endurance, service life and power adjustment of each component of the vehicle. As the electrical system of the vehicle is becoming more and more complex, it is necessary to obtain the electric quantity balance of the power consumption test of the vehicle electrical accessories during the development of the vehicle.

[0003] The domestic forklift industry is currently mainly powered by pure electric or pure internal combustion engine, and the hybrid forklift has not been mass-produced and applied. The method for evaluating and testing the power performance of the forklift in the industry is only formulated for pure electric or pure internal combustion engine models, and the evaluation method for the electric quantity balance of the hybrid forklift is still blank. In addition, the existing forklifts, whether electric or internal combustion, are evaluated based on the endurance time and work energy consumption, which cannot evaluate the electric quantity balance of the hybrid forklift under actual complex working conditions. Therefore, it is necessary to develop a detection method for the electric quantity balance of the hybrid forklift. SUMMARY

[0004] The present application aims to provide a detection method for the electric quantity balance of a hybrid forklift to solve the problems in the background art.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] A detection method for the electric quantity balance of a hybrid forklift, comprising the following steps:

[0007] (1) setting the driving distance and speed of the forklift under two conditions of empty load and full load in each section of working condition;

[0008] (2) adjusting the electric quantity V0 of the lithium battery pack of the forklift, so that V0 is 50% of the total electric quantity V;

[0009] (3) starting the forklift to perform straight driving, turning, jolting, uphill driving and downhill driving under the condition of empty load, and lifting and straight driving under the condition of full load;

[0010] (4) After all the operations in step (3) are completed, stop the vehicle and check the power V1 of the lithium battery pack. If 55%V > V1 > 50%V, it indicates that the power of the hybrid forklift is balanced. If V1 < 50%V, it indicates that the hybrid forklift is underpowered and the generator power needs to be increased and the lithium battery pack capacity needs to be adjusted. If V1 > 55%V, it indicates that the power generation capacity of the hybrid forklift is too strong and the generator power can be appropriately reduced and the lithium battery pack capacity adjusted.

[0011] Increasing the generator's power and adjusting the lithium battery pack capacity means increasing the battery pack capacity proportionally to the increase in generator power. For example, if the original generator power was 30kW and the battery was 20kWh, and the generator power is increased to 35kW, then the battery capacity needs to be increased to 20*35 / 30kWh.

[0012] Further, in step (1), each working condition includes straight driving, turning, uphill, downhill driving on a smooth road surface, and straight driving on a bumpy road surface.

[0013] In a further embodiment, the forklift travel distance refers to a straight-line distance of 6-20 meters on a flat road surface under no-load conditions, a straight-line distance of 20-25 meters on a bumpy road surface, and a distance of 10-15 meters on both uphill and downhill slopes; and a straight-line distance of 15-25 meters on a flat road surface under full load conditions.

[0014] In a further embodiment, the turning refers to turning 90 degrees to the left or right with the minimum turning radius while stationary, ensuring that the center point of the vehicle's front axle remains on the center line of the test path; the slope of the uphill and downhill sections is 18-25°. That is, to ensure the accuracy of the test path and distance, calculations and simulations are used to set the turning to the minimum turning radius condition, ensuring that the center point of the vehicle's front axle remains on the center line of the reinforced test path.

[0015] Further proposed solutions include: forklift speeds of <5 km / h when turning or on bumpy roads, <10 km / h when going downhill, <20 km / h when traveling straight on flat roads, and <5 km / h when traveling straight on bumpy roads.

[0016] Further, in order to control the operating speed and ensure that the forklift's operating intensity can meet market requirements, after scenario calculation, it was determined that the total time for one cycle of operation of the hybrid forklift, i.e., all operations in step (3), is <260S.

[0017] In a further embodiment, step (3) includes lifting at full speed to the top under full load and then lowering at full speed to the original position, and lifting at full speed to the middle position under full load and then lowering at full speed to 300mm above the ground.

[0018] In a further step, after the forklift performs turning, bumping, uphill, downhill and lifting operations, a straight-line driving section is implemented in step (3).

[0019] The battery balance detection method for hybrid forklifts disclosed in this application can solve the problem of battery depletion caused by complex changes in the power output of hybrid forklifts, which affects the normal operation of the forklifts. Existing forklifts, whether electric or internal combustion models, are evaluated based on range and energy consumption, and cannot assess the battery balance of hybrid forklifts under actual complex working conditions.

[0020] The detection method in this application simulates and covers most high-intensity user scenarios through analysis of actual user operations; while existing evaluation methods still lack evaluation of power balance and do not include analysis and simulation of actual user operation scenarios.

[0021] The testing method in this application adds constraints such as an initial lithium battery pack charge of 50% of the total charge, simulation of actual user operation scenarios and parameter settings, and a total process time of <260 seconds, as a basis for ensuring the power balance evaluation of the hybrid forklift. Furthermore, the capacity of the lithium battery pack is adjusted based on the battery charge after the test. Specifically: if the lithium battery pack charge V1 < 50%, the hybrid forklift is underpowered and does not meet the requirements, requiring an increase in generator power and adjustment of the lithium battery pack capacity; if 55% > V1 > 50%, the hybrid forklift is in power balance and meets the requirements. If V1 > 55%, the hybrid forklift's generator capacity is too strong, and it is advisable to appropriately reduce the generator power and adjust the lithium battery pack capacity to reduce costs. Existing evaluation methods clearly do not consider hybrid characteristics and therefore lack the conditions for evaluating the power balance of hybrid forklifts.

[0022] This application demonstrates how to start a forklift to perform straight-line, turning, bumpy, uphill, and downhill operations when unloaded, and lifting and straight-line operations when fully loaded. The entire operation time is controlled within 260 seconds, meaning the entire testing time is compact and highly efficient. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the principle of the hybrid forklift used in this application.

[0024] Figure 2 This is the detection process for Embodiment 2 of this application. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1:

[0027] like Figure 1 The diagram illustrates the working principle of a hybrid forklift. Engine 1 drives generator 2 to charge lithium battery pack 3, with engine 1 always operating in its high-efficiency range. Lithium battery pack 3 simultaneously supplies power to the travel motor 10 and pump motor 4. Travel motor 10 drives gearbox 11 to transmit power to drive axle 8, enabling the forklift to move. Pump motor 4 drives hydraulic pump 5, which, through multi-way valve 6, delivers hydraulic oil to lifting cylinders, controlling the lifting of mast system 7 and thus achieving the lifting and lowering operation of the forklift. Control system 9 collects key parameters from engine 1, generator 2, lithium battery pack 3, travel motor 10, and pump motor 4 to control the vehicle's power output, temperature, and battery limits.

[0028] Example 2:

[0029] A method for detecting the battery balance of a hybrid forklift, comprising the following steps:

[0030] (1) Set the travel distance and speed of the forklift under the two states of no load and full load in each working condition; where each working condition includes straight travel, turning, uphill, downhill and straight travel on flat road surface;

[0031] The driving distance is set as follows: under no-load conditions, the straight-line distance on a smooth road is 6-20 meters, the straight-line distance on a bumpy road is 20-25 meters, and the distance on uphill and downhill slopes is 10-15 meters; under full load conditions, the straight-line distance on a smooth road is 15-25 meters.

[0032] The driving speed is set as follows: the forklift speed is <5KM / h when turning and on bumpy roads, <10KM / h when going downhill, <20KM / h when traveling straight on flat roads, and <5KM / h when traveling straight on bumpy roads.

[0033] (2) Adjust the charge V0 of the forklift lithium battery pack so that V0 is 50% of the total charge V;

[0034] (3) Start the forklift and perform straight, turning, bumping, uphill and downhill operations when unloaded, and lift and straight operations when fully loaded; the total time of all operations is less than 260 seconds; and after the forklift performs turning, bumping, uphill, downhill and lift operations, perform a straight drive for a period of time.

[0035] (4) After all the operations in step (3) are completed, stop the vehicle and check the power V1 of the lithium battery pack. If 55%V > V1 > 50%V, it indicates that the power of the hybrid forklift is balanced. If V1 < 50%V, it indicates that the hybrid forklift is underpowered and the generator power needs to be increased and the lithium battery pack capacity needs to be adjusted. If V1 > 55%V, it indicates that the power generation capacity of the hybrid forklift is too strong and the generator power can be appropriately reduced and the lithium battery pack capacity adjusted.

[0036] Increasing the generator's power and adjusting the lithium battery pack capacity involves proportionally increasing the battery pack capacity based on the increase in generator power. For example, if the original generator power was 30kW and the battery was 20kWh, and the generator power is increased to 35kW, then the battery capacity needs to be increased to 20*35 / 30kWh. The same procedure applies when decreasing the generator's power and adjusting the lithium battery pack capacity.

[0037] In this application, turning refers to turning 90 degrees to the left or right with the minimum turning radius while still in place, ensuring that the center point of the front axle of the vehicle body is always on the center line of the test path; the slope of the uphill and downhill road surface is 18-25°.

[0038] In step (3), the lifting and lowering includes lifting at full speed to the top under full load and then lowering at full speed to the original position, and lifting at full speed to the middle position under full load and then lowering at full speed to 300mm above the ground.

[0039] Example 3:

[0040] Specific implementation examples in this application Figure 2 As shown:

[0041] Based on industry standards and market demand, the operation of hybrid electric forklifts is segmented according to the enhanced test conditions. The travel distance and forklift status of each segment are set, with start-stop, turning, lifting, and obstacle as the dividing lines.

[0042] Before the test, the hybrid forklift's lithium battery pack was charged at 50% of its total capacity. Assuming the total capacity of the lithium battery pack was 20 kWh, the required current capacity was 10 kWh. The hybrid forklift traveled straight for 12 meters unloaded, then made a 90-degree left turn unloaded, continued straight for 7.5 meters unloaded, made a 90-degree right turn, lifted a fully loaded heavy block (the block's mass was the same as the forklift's full lifting capacity), and quickly returned the block to its original position. The forklift then reversed unloaded, turned left, and resumed its straight path. It continued straight for 20 meters unloaded, made a 90-degree left turn unloaded, lifted a fully loaded heavy block to the middle height, and quickly lowered it to 300 mm above the ground. The forklift then reversed fully loaded with the heavy block and resumed its straight path. The route is as follows: Fully loaded, proceed straight for 20m; turn right at a 90-degree angle while fully loaded; unload the load; turn left and reverse back to the straight path; continue straight for 7.5m unloaded; turn left at a 90-degree angle while unloaded; proceed straight for 24m unloaded, passing a standard bumpy road; turn left at a 90-degree angle and proceed straight for 7.5m; climb a 20-degree slope for 12.5m unloaded; proceed straight for 6m unloaded; descend a 15-degree slope for 12.5m unloaded; proceed straight for 7.5m unloaded; turn left at a 90-degree angle while unloaded; proceed straight for 12m unloaded. The entire process takes less than 260 seconds.

[0043] After the operation test is completed, test the current lithium battery pack charge. If the lithium battery pack charge V1 < 50%, the hybrid forklift is underpowered and does not meet the requirements, requiring an increase in generator power and adjustment of the lithium battery pack capacity. If 55% > V1 > 50%, the hybrid forklift is balanced and meets the requirements. If V1 > 55%, the hybrid forklift's generator capacity is too strong, and it is advisable to appropriately reduce the generator power and adjust the lithium battery pack capacity to reduce costs.

[0044] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0045] Therefore, the above description is only a preferred embodiment of this application and is not intended to limit the scope of this application; that is, all equivalent modifications made in accordance with the scope of the claims of this application shall be within the protection scope of the claims of this application.

Claims

1. A method for detecting the battery balance of a hybrid forklift, characterized in that: Includes the following steps: (1) Set the travel distance and travel speed of the forklift under the two states of no load and full load in each working condition; (2) Adjust the charge V0 of the forklift lithium battery pack so that V0 is 50% of the total charge V; (3) Start the forklift and perform straight-line, turning, bumping, uphill and downhill operations when unloaded, and lift and straight-line operations when fully loaded; the total time of all the above operations is less than 260 seconds; The lifting and lowering includes raising the vehicle to the top at full speed under full load and then lowering it to the original position at full speed, and raising it to the middle position at full speed under full load and then lowering it to 300mm above the ground. (4) After all the operations in step (3) are completed, stop the vehicle and check the power V1 of the lithium battery pack. If 55%V > V1 > 50%V, it indicates that the power of the hybrid forklift is balanced. If V1 < 50%V, it indicates that the hybrid forklift is underpowered and the generator power needs to be increased and the lithium battery pack capacity needs to be adjusted. If V1 > 55%V, it indicates that the power generation capacity of the hybrid forklift is too strong and the generator power needs to be appropriately reduced and the lithium battery pack capacity needs to be adjusted.

2. The detection method according to claim 1, characterized in that: The working conditions in step (1) include straight driving, turning, uphill, downhill driving on flat roads and straight driving on bumpy roads.

3. The detection method according to claim 2, characterized in that: The forklift travel distance refers to the following: under no-load conditions, the straight-line distance on a flat road is 6-20 meters; the straight-line distance on a bumpy road is 20-25 meters; and the distance on uphill and downhill slopes is 10-15 meters. Under full load conditions, the straight-line distance on a flat road is 15-25 meters.

4. The detection method according to claim 2, characterized in that: The turning refers to turning 90 degrees to the left or right with the minimum turning radius while stationary, ensuring that the center point of the front axle of the vehicle body is always on the center line of the test path; the slope of the uphill and downhill road surfaces is 18-25°.

5. The detection method according to claim 2, characterized in that: Forklifts should travel at speeds of less than 5 km / h when turning or on bumpy roads, less than 10 km / h when going downhill, less than 20 km / h when traveling straight on flat roads, and less than 5 km / h when traveling straight on bumpy roads.

6. The detection method according to claim 1, characterized in that: In step (3), after the forklift performs turning, bumping, uphill, downhill and lifting operations, it travels straight for a period of time.

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