Range extender assembly applied to hybrid mowing vehicle and control driving method

Abstract

The invention discloses a range extender assembly applied to a hybrid mowing vehicle and a control driving method, the range extender assembly is applied to the technical field of hybrid mowing vehicles, the range extender assembly comprises an engine system, a generator system and a range extender control unit, a rotor of the generator assembly is connected with a crankshaft of the engine assembly, a fan assembly is arranged on the air inlet side of the engine assembly, and the fan assembly is connected with the generator system. The fan assembly is connected to the crankshaft, the air outlet position of the fan assembly is aligned with a cylinder head of the engine assembly, and the range extender control unit is used for determining the target output power of the range extender assembly according to the corresponding relation between the required power and the target output power; selecting target mechanical power corresponding to the high efficiency point according to a preset target mechanical power curve corresponding to the target output power; and determining a target rotating speed and a target torque corresponding to the target mechanical power, and outputting power according to the target rotating speed and the target torque. The frequency can be adjusted according to different working conditions, adaptability and flexibility are good, the structure is simple, and cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of general locomotives, and particularly to a range extender assembly and a control driving method applied to a hybrid lawn mower. Background Art

[0002] At present, most of the lawn mowers on the market are pure fuel lawn mowers or pure electric lawn mowers. For the pure fuel lawn mower, the power is output from the engine to the drive wheels and the cutter head through a hydraulic bridge, and for the pure electric lawn mower, the power is output from the battery to the drive motor and the lawn mower motor. The traditional fuel-powered lawn mower has poor NVH performance and high fuel consumption, while the pure electric lawn mower has a short working endurance and high battery cost. Even for a small number of hybrid lawn mowers, the lawn mower can only generate electricity at a fixed power, that is, the output frequency of the generator always remains at a fixed value (such as 50 Hz or 60 Hz), and it can only be applied to the lawn mowing operation scenarios with relatively stable power requirements and little change in working conditions, and is not suitable for complex working conditions with frequent power adjustment, and has poor adaptability and flexibility.

[0003] Moreover, for general-purpose engine, the engine is started by a hand-pull start or an electric start. Among them, the hand-pull start is to start the engine by manually pulling the pull rope disk connected to the engine crankshaft to rotate the crankshaft; the electric start is to start the engine by the starting motor connected to the engine crankshaft, and the motor is rotated by electricity, and then the crankshaft is driven to rotate to start the engine. Starting the engine requires a starting motor, and the structure of the engine is complex and the cost is high.

[0004] At the same time, the engine cooling adopts a water-cooled type, and the engine cylinder head needs to be provided with components such as a water jacket, a water pump, and a water temperature sensor, and the engine structure and production process are complex.

[0005] In summary, how to effectively solve the problems of poor adaptability and complex structure of the existing hybrid lawn mower is an urgent problem to be solved by those skilled in the art at present. Summary of the Invention

[0006] The purpose of the present invention is to provide a range extender assembly and a control driving method applied to a hybrid lawn mower, which can adjust the frequency according to different working conditions, have good adaptability and flexibility, simple structure, and low cost.

[0007] To solve the above technical problems, the present invention provides the following technical solutions:

[0008] An extender assembly for a hybrid lawn mower, the extender assembly comprising an engine system, a generator system and an extender control unit, the engine system comprising an engine assembly and an engine control unit, the generator system comprising a generator assembly and a generator control unit, a rotor of the generator assembly being connected to a crankshaft of the engine assembly, a fan assembly being provided on an intake side of the engine assembly, the fan assembly being connected to the crankshaft and having an air outlet position aligned with a cylinder head of the engine assembly, the extender control unit being connected to the engine control unit and the generator control unit,

[0009] The extender control unit is configured to determine a target output power of the extender assembly according to a correspondence between a required power and a target output power; select a target mechanical power of the extender assembly corresponding to an efficiency high point according to a preset target mechanical power curve corresponding to the target output power of the extender assembly; determine a target speed and a target torque corresponding to the target mechanical power, and send them to the engine control unit and the generator control unit; and control the engine assembly and the generator assembly to output power according to the target speed and the target torque.

[0010] Optionally, an installation shaft and an adjustment shaft parallel to the crankshaft are provided in the engine assembly, the fan assembly is installed on the installation shaft, belt pulleys are provided on the installation shaft, the crankshaft and the adjustment shaft, and the belt pulleys of the three are connected by a belt. The adjustment shaft can make a circular motion around the crankshaft, and the installation shaft follows the adjustment shaft to move so that the air outlet position of the fan assembly is aligned with the cylinder head of the engine assembly.

[0011] Optionally, it further includes:

[0012] A temperature sensor installed on the cylinder head for detecting the temperature of the cylinder head;

[0013] A moving driving device connected to the temperature sensor and used to drive the installation shaft to move along its axis so that the temperature of the cylinder head is maintained within a set range.

[0014] Optionally, the moving driving device includes an electromagnet provided at an outer end of a housing of the engine assembly. The electromagnet is coaxial with the installation shaft. When the electromagnet is energized, an electromagnetic force of the electromagnet on the installation shaft drives the installation shaft to move towards an end close to the cylinder head; and a return spring provided on the installation shaft for driving the installation shaft to return to its initial position is further included.

[0015] The present invention provides a driving method for an extender assembly for a hybrid lawn mower as described in any one of the above, comprising the steps of:

[0016] Using the formula Calculate the required power of the lawn mower, where is the required power, is the driving power of the lawn mower, is the mowing power of the lawn mower, is the charge and discharge power of the power battery, is the power of other loads of the lawn mower;

[0017] Determine the target output power of the range extender assembly according to the corresponding relationship between the required power and the target output power;

[0018] Select the target mechanical power of the range extender assembly corresponding to the high-efficiency point according to the preset target mechanical power curve corresponding to the target output power of the range extender assembly;

[0019] Determine the target speed and target torque corresponding to the target mechanical power, and send them to the engine control unit and the generator control unit;

[0020] Control the engine assembly and the generator assembly to output power according to the target speed and the target torque.

[0021] Optionally, according to the formula, the corresponding relationship between the required power and the target output power specifically includes:

[0022] Compare the required power and the target output power,

[0023] When the battery SOC is greater than the upper threshold, determine that the target output power = the required power - the discharge power of the battery;

[0024] When the battery SOC is between the lower threshold and the upper threshold, determine that the target output power = the required power;

[0025] When the battery SOC is less than the lower threshold, determine that the target output power = the required power + the charging power of the battery.

[0026] Optionally, between selecting the preset target mechanical power curve corresponding to the target output power of the range extender assembly and sending it to the engine control unit and the generator control unit, it further includes:

[0027] Select multiple target mechanical powers corresponding to the high-efficiency points as alternative target mechanical powers;

[0028] Select the optimal target mechanical power from the multiple alternative target mechanical powers according to the overall performance of the lawn mower;

[0029] Determine the optimal target speed and optimal target torque corresponding to the optimal target mechanical power, and send them to the engine control unit and the generator control unit.

[0030] Optionally, after controlling the engine assembly and the generator assembly to output power according to the target speed and the target torque, the method further includes:

[0031] Detecting the actual output voltage and the actual output current of the generator assembly;

[0032] Receiving the actual output voltage and the actual output current, and using the formula to calculate the actual output power of the range extender assembly, where is the actual output power of the range extender assembly, is the actual output voltage of the generator assembly, is the actual output current of the generator assembly;

[0033] Comparing the actual output power with the target output power. When the actual output power is greater than the target output power, reducing the actual output power of the range extender assembly until it is equal to the target output power; when the actual output power is less than the target output power, increasing the actual output power of the range extender assembly until it is equal to the target output power.

[0034] Optionally, the method for the range extender control unit to control the start of the engine assembly includes:

[0035] Combining the current temperature and the crankshaft position of the engine assembly to calculate the magnitude of the starting target torque required for the current start;

[0036] Sending the starting target torque to the generator control unit to control the generator assembly to output torque at the starting target torque, and the rotor of the generator assembly drives the crankshaft of the engine assembly to rotate;

[0037] Monitoring the actual speed of the generator assembly, and comparing the actual speed with a preset speed. When the actual speed reaches the preset speed, controlling the engine assembly to start.

[0038] Optionally, the magnitude of the starting target torque is estimated based on the starting target time, the starting target speed, the frictional loss torque, the pumping loss torque, and the compression loss torque. The specific method includes:

[0039] According to the formula calculate the starting target angular velocity, where n is the starting target speed;

[0040] According to the formula calculate the starting angular acceleration, where t is the starting target time;

[0041] According to the formula Calculate the starting resultant torque, where I is the moment of inertia;

[0042] According to the formula Calculate the starting target torque, where is the frictional loss torque, is the pumping loss torque, is the compression loss torque.

[0043] The beneficial effect of the present invention lies in that the range extender assembly applied to the hybrid lawn mower provided by the present invention includes an engine system, a generator system and a range extender control unit. Among them, the engine system includes an engine assembly and an engine control unit, and the engine assembly is the power source, generating mechanical energy by burning fuel. The generator system includes a generator assembly and a generator control unit, and the rotor of the generator assembly is connected to the crankshaft of the engine assembly.

[0044] The range extender control unit interacts with the engine control unit and the generator control unit through a network. The range extender control unit determines the target output power of the range extender assembly according to the corresponding relationship between the actual required power and the target output power of the lawn mower. A target mechanical power curve is provided in the range extender control unit. Based on the preset target mechanical power curve corresponding to the target output power, the range extender control unit selects the target mechanical power of the range extender assembly corresponding to the high-efficiency point. The target speed and target torque corresponding to the target mechanical power are determined from the target mechanical power curve, and the target speed and target torque are sent to the engine control unit and the generator control unit. The engine control unit and the generator control unit control the engine assembly and the generator assembly to output power according to the requirements, realizing the variable working condition output of the range extender assembly.

[0045] Applying the technical solution provided by the embodiment of the present invention, the output frequency of the generator can be adjusted according to the working conditions, effectively coping with the power demand fluctuations in the lawn mowing operation scenario, ensuring that the engine and the generator always work in the high-efficiency speed range, improving the flexibility and adaptability of the system, reducing mechanical losses and energy waste, extending the equipment life, and being better applicable to complex working conditions with frequent power adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0047] Figure 1Schematic diagram of the range extender assembly applied to a hybrid lawn mower provided by a specific embodiment of the present invention;

[0048] Figure 2 Schematic diagram of the principle of the range extender assembly;

[0049] Figure 3 Connection schematic diagram of the fan assembly;

[0050] Figure 4 Flow chart of the driving method of the range extender assembly applied to a hybrid lawn mower;

[0051] Figure 5 Preset target mechanical power curve graph;

[0052] Figure 6 Schematic diagram of the range extender power system provided by a specific embodiment of the present invention;

[0053] Figure 7 Schematic diagram of the balance device between the generator and the engine;

[0054] Figure 8 Schematic diagram of the range extender pressure balance device;

[0055] Figure 9 Schematic diagram of the water-cooled motor of the generator.

[0056] Reference numerals:

[0057] 1 - Engine system; 2 - Generator system; 3 - Range extender control unit; 4 - Electromagnet; 5 - Mounting shaft; 6 - Pulley; 7 - Fan assembly; 8 - Cylinder head; 9 - Power battery; 10 - Energy distribution unit; 11 - Drive motor controller; 12 - Water inlet nozzle; 13 - Water outlet nozzle; 14 - Water inlet and outlet dividing part; 15 - Water inlet; 16 - Water outlet; 17 - Outer water jacket; 18 - O-ring; 19 - Inner water jacket; 20 - Lawn mower motor controller; 21 - Lawn mower motor; 22 - Battery; 23 - Power conversion device; 24 - Drive motor; 25 - Reduction gearbox; 26 - Crankcase; 27 - Crankshaft; 28 - Intermediate end cover; 29 - Motor chamber; 30 - Rotor; 31 - Stator; 32 - Rear end cover; 33 - Waterproof and breathable membrane; 34 - Oil seal; 35 - Flywheel; 36 - Fastener. Specific embodiment

[0058] The object of the present invention is to provide a range extender assembly and a control driving method applied to a hybrid lawn mower, which can adjust the frequency according to different working conditions, have good adaptability and flexibility, simple structure and low cost.

[0059] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0060] In a specific embodiment, as Figures 1 to 3 shown, the range extender assembly applied to a hybrid lawn mower provided by the present invention includes an engine system 1, a generator system 2, and a range extender control unit 3. The engine system 1 includes an engine assembly and an engine control unit. The generator system 2 includes a generator assembly and a generator control unit. The rotor of the generator assembly is connected to the crankshaft of the engine assembly. A fan assembly 7 is provided on the intake side of the engine assembly. The fan assembly 7 is connected to the crankshaft and its air outlet position is aligned with the cylinder head 8 of the engine assembly. The range extender control unit 3 is connected to the engine control unit and the generator control unit.

[0061] The range extender control unit 3 is configured to determine the target output power of the range extender assembly according to the correspondence between the required power and the target output power; select the target mechanical power of the range extender assembly corresponding to the high-efficiency point according to the preset target mechanical power curve corresponding to the target output power of the range extender assembly; determine the target speed and target torque corresponding to the target mechanical power, and send them to the engine control unit and the generator control unit; control the engine assembly and the generator assembly to output power according to the target speed and target torque.

[0062] In the above structure, the range extender assembly includes an engine system 1, a generator system 2, and a range extender control unit 3. Among them, the engine system 1 includes an engine assembly and an engine control unit. The engine assembly is the power source and generates mechanical energy by burning fuel. The generator system 2 includes a generator assembly and a generator control unit. The rotor of the generator assembly is connected to the crankshaft of the engine assembly.

[0063] The range extender control unit 3 interacts with the engine control unit and the generator control unit through a network, receives the current working state information of the engine control unit and the generator control unit, and sends control commands to implement functions such as starting, stopping, and variable-condition operation of the range extender assembly. The range extender control unit 3 can be integrated in the engine control unit and the generator control unit or a separate controller hardware.

[0064] The power of the range extender assembly is generated by the engine system 1. After the mechanical energy generated by the engine system 1 is converted into electrical energy by the generator system 2, it is output to the power battery, the drive motor, and the lawn mower motor.

[0065] Different from pure fuel lawn mowers, the engine system 1 of the range extender assembly has no direct mechanical connection with the drive wheels and the cutter deck. This decouples the engine system 1 speed of the range extender assembly from the vehicle operating conditions. Combining with the vehicle power demand, the engine system 1 speed is controlled through the generator system 2, and the engine system 1 can operate under conditions with lower fuel consumption and better NVH performance, improving the overall user experience of the lawn mower.

[0066] Different from pure electric lawn mowers, the vehicle power is generated by the engine system 1 of the range extender assembly and converted into electrical energy through the generator system 2 and then output to the drive motor and the mowing motor. This enables the lawn mower equipped with the range extender assembly to improve the overall vehicle endurance performance while taking into account the electric drive performance of pure electric lawn mowers, reducing the vehicle power battery capacity and cost.

[0067] During the operation of the lawn mower, the power demand will vary due to factors such as terrain, grass density, and operation speed. For example, when operating in dense grass or on an uphill slope, a higher power output is required; when operating on flat terrain or in sparse grass, the power demand is relatively low. When operating in large areas of farmland, a continuous and stable high power output is required; when operating in urban green belts or small areas of lawns, the power demand changes frequently.

[0068] To adapt to the above various complex mowing conditions, the range extender control unit 3 determines the target output power of the range extender assembly according to the corresponding relationship between the actual demand power and the target output power of the lawn mower. There is a target mechanical power curve in the range extender control unit 3. Based on the preset target mechanical power curve corresponding to the target output power, the range extender control unit 3 selects the target mechanical power of the range extender assembly corresponding to the high-efficiency point. The target speed and target torque corresponding to the target mechanical power are determined from the target mechanical power curve and sent to the engine control unit and the generator control unit. The engine control unit and the generator control unit control the engine assembly and the generator assembly to output power according to the requirements, realizing the variable condition output of the range extender assembly.

[0069] Applying the technical solution provided by the embodiment of the present invention, the generator output frequency can be adjusted according to the working conditions, effectively coping with the power demand fluctuations in the mowing operation scenario, ensuring that the engine and the generator always operate in the high-efficiency speed range, improving the flexibility and adaptability of the system, reducing mechanical losses and energy waste, extending the equipment life, and being better applicable to complex working conditions with frequent power adjustments.

[0070] An air-cooled general-purpose engine is adopted. A fan assembly 7 is provided on the intake side of the engine assembly. The fan assembly 7 is connected to the crankshaft and its air outlet position is aligned with the cylinder head 8 of the engine assembly. The main function of the fan assembly 7 is to provide cooling for the engine, ensure that the engine operates within a normal temperature range, and avoid performance degradation or failures caused by overheating. The air-cooled engine does not have structures such as an engine cylinder head water jacket, a water pump, and a water temperature sensor, and the engine structure and production process are simpler.

[0071] Based on the above various specific embodiments, an installation shaft 5 and an adjustment shaft parallel to the crankshaft are provided in the engine assembly. The fan assembly 7 is installed on the installation shaft 5. Pulley 6 is provided on the installation shaft 5, the crankshaft, and the adjustment shaft. The pulleys 6 of the three are connected by a belt. The adjustment shaft can make a circular motion around the crankshaft, and the installation shaft 5 follows the adjustment shaft to move so that the air outlet position of the fan assembly 7 is aligned with the cylinder head 8 of the engine assembly.

[0072] In a specific embodiment, the installation shaft 5, the crankshaft, and the adjustment shaft are connected by a pulley 6. The installation shaft 5, the crankshaft, and the adjustment shaft are located at the vertices of the triangle formed by the belt. Power transmission and position adjustment are achieved through belt drive, with a simple structure, high reliability, and low maintenance cost.

[0073] The adjustment shaft can make a circular motion around the crankshaft. By rotating the adjustment shaft, the installation shaft 5 is driven to move. Since the total length of the belt is fixed and the distance between the adjustment shaft and the crankshaft is fixed, when the distance between the adjustment shaft and the installation shaft 5 changes, the distance between the installation shaft 5 and the crankshaft changes, so that the air outlet position of the fan assembly 7 can be accurately aligned with the cylinder head 8 of the engine assembly to ensure the best cooling effect.

[0074] In the above embodiments, the movement of the adjustment shaft can accurately control the position of the installation shaft 5 to achieve dynamic adjustment of the position of the fan assembly 7. The position of the fan assembly 7 can be dynamically adjusted according to the operating state and working conditions of the engine to ensure that the air outlet position is always aligned with the engine cylinder head 8 to provide the best cooling effect. At the same time, it can adapt to the cooling requirements under different working conditions. For example, when operating at high load, the fan can be more accurately aligned with the cylinder head 8 to improve the cooling efficiency; when at low load, the position can be appropriately adjusted to reduce energy loss.

[0075] In a preferred embodiment, an arc-shaped groove is provided on the housing of the engine assembly. The end of the adjustment shaft is connected to the arc-shaped groove. The adjustment shaft is connected to a driving motor, and the driving motor drives the adjustment shaft to move along the arc-shaped groove. The arc-shaped groove has a limiting effect on the adjustment shaft.

[0076] In another preferred embodiment, the mounting shaft 5 is a right-angle shaft, including a horizontal shaft and a vertical shaft connected to each other. The vertical shaft is connected to the crankshaft, the horizontal shaft is parallel to the crankshaft, and the fan assembly 7 is connected to the horizontal shaft. Specifically, the length of the vertical shaft can be determined according to the position of the cylinder head 8. The length of the vertical shaft needs to ensure that the air outlet position of the fan assembly 7 can accurately align with the cylinder head 8 of the engine assembly. The length of the horizontal shaft can be determined by the axial distance from the cylinder head 8, and the axial distance needs to ensure that the fan assembly 7 provides cold air with appropriate intensity to the cylinder head 8.

[0077] Based on the above specific embodiments, it further includes:

[0078] A temperature sensor installed on the cylinder head 8 for detecting the temperature of the cylinder head 8;

[0079] A moving driving device connected to the temperature sensor and used to drive the mounting shaft 5 to move along its axis direction to keep the temperature of the cylinder head 8 within a set range.

[0080] In a specific embodiment, the temperature sensor monitors the temperature of the cylinder head 8 in real time. The temperature sensor transmits the temperature information of the cylinder head 8 to the control system. When the temperature exceeds the set threshold, the control system triggers the moving driving device, and the moving driving device drives the mounting shaft 5 to move along its axis direction. For example, when the temperature of the cylinder head 8 is relatively low, the fan assembly 7 can be appropriately far away from the cylinder head 8 to reduce unnecessary energy consumption.

[0081] In the above embodiment, through the coordinated operation of the temperature sensor and the moving driving device, the system can dynamically adjust the position of the fan assembly 7 according to the actual temperature of the cylinder head 8 to ensure that the temperature of the cylinder head 8 remains within the set range and ensure that the cooling effect is always in the best state.

[0082] Based on the above specific embodiments, the moving driving device includes an electromagnet 4 provided at the outer end of the housing of the engine assembly. The electromagnet 4 is coaxial with the mounting shaft 5. When the electromagnet 4 is energized, the electromagnetic force of the electromagnet 4 drives the mounting shaft 5 to move towards the end close to the cylinder head 8; it further includes a return spring provided on the mounting shaft 5 for driving the mounting shaft 5 to return to its initial position.

[0083] In a specific embodiment, the electromagnet 4 is connected to the control system. When the temperature of the cylinder head 8 exceeds the set threshold, the control system triggers the electromagnet 4 to be energized. After the electromagnet 4 is energized, it generates an electromagnetic force, and the electromagnetic force pushes the mounting shaft 5 to move towards the end close to the cylinder head 8, making the fan assembly 7 close to the cylinder head 8 and adjusting the position of the fan assembly 7, thereby adjusting the cooling effect of the fan assembly 7.

[0084] A return spring is provided on the mounting shaft 5, and the elastic force of the return spring ensures that the mounting shaft 5 can quickly return to its initial position after the electromagnet 4 loses its electromagnetic force, ensuring the stability and reliability of the system.

[0085] By dynamically adjusting the magnitude of the current of the electromagnet 4, the magnitude of the electromagnetic force can be adjusted. For example, when the current is relatively large, the electromagnetic force is greater than the elastic force of the return spring, pushing the mounting shaft 5 to move towards one end close to the cylinder head 8. When the current is relatively small, the electromagnetic force is less than the elastic force of the return spring, pushing the mounting shaft 5 to move towards one end away from the cylinder head 8, thereby realizing the dynamic adjustment of the position of the fan assembly 7 to accurately determine the optimal cooling position.

[0086] It should be noted that due to the flow field effect, the relationship between the position of the specific fan assembly 7 and the cooling effect can be determined by dynamically adjusting the position of the fan assembly 7.

[0087] In a preferred embodiment, it further includes:

[0088] A position sensor for detecting the axial distance between the fan assembly 7 and the cylinder head 8;

[0089] A database connected to the position sensor and the temperature sensor for recording the corresponding relationship between the axial distance between the fan assembly 7 and the cylinder head 8 and the temperature of the cylinder head 8;

[0090] A query device connected to the database for querying the axial distance corresponding to the temperature of the cylinder head 8 within a preset range in the database.

[0091] The corresponding relationship between the axial distance and the temperature of the cylinder head 8 can be used as a data reference for subsequent quick and accurate adjustment of the fan position.

[0092] In the above embodiment, through the cooperative action of the electromagnet 4 and the return spring, the position of the fan assembly 7 can be dynamically adjusted according to the actual temperature of the cylinder head 8 to ensure that the cooling effect is always in the best state.

[0093] As Figure 4 shown, it is a flowchart of a driving method of an extender assembly applied to a hybrid lawn mower as described in any one of the above, and the method includes the following steps:

[0094] S100, use the formula to calculate the required power of the lawn mower, where is the required power, is the driving power of the lawn mower, is the mowing power of the lawn mower, is the charge and discharge power of the power battery, is the other load power of the lawn mower;

[0095] In practical applications, the power demand of the lawn mower = mowing power + driving power + charge / discharge power of the power battery + other electrical load power. Therefore, the required power of the lawn mower can be calculated by the following formula where, is the driving power of the lawn mower, which is the power required to maintain the vehicle's driving. is the mowing power of the lawn mower, which is the power required to drive the mowing device. is the charging and discharging power of the power battery. A positive value represents the charging power, and a negative value represents the discharging power. is the power of other loads of the lawn mower, such as the power required for lighting, electronic devices, etc.

[0096] By accurately calculating the total required power of the lawn mower under the current working conditions, it provides a basis for subsequent power distribution.

[0097] S110, according to the corresponding relationship between the required power and the target output power, determine the target output power of the range extender assembly;

[0098] In practical applications, according to the calculated required power, combined with the preset corresponding relationship between the target output power and the required power, determine the target output power of the range extender assembly. The target output power of the range extender assembly can meet the actual needs of the lawn mower, while avoiding power surplus or deficiency.

[0099] S120, according to the preset target mechanical power curve corresponding to the target output power of the range extender assembly, select the target mechanical power of the range extender assembly corresponding to the high-efficiency point;

[0100] In practical applications, according to the formula the target output power of the range extender assembly can be calculated, where is the efficiency of the generator assembly, is the efficiency of the generator control unit, is the target output power of the range extender assembly, is the target mechanical power of the range extender assembly. The efficiency of the generator assembly and the efficiency of the generator control unit are the inherent properties of the hardware itself. The target output power of the range extender assembly is inversely proportional to the target mechanical power of the range extender assembly. After the target output power of the range extender assembly is determined, to obtain a smaller target mechanical power of the range extender assembly, high efficiency is required, that is, the total efficiency of the generator assembly efficiency and the generator control unit efficiency is high.

[0101] According to the target output power of the range extender assembly, look up the preset target mechanical power curve, such as Figure 5As shown in the preset target mechanical power curve, the abscissa represents the rotational speed and the ordinate represents the torque. Curve A and curve B in the figure represent two target mechanical powers, and the contour lines in the figure represent the generator system efficiency. The numbers on the contour lines represent the values of the generator system efficiency. Select the target mechanical power corresponding to the point with high efficiency, that is, select the operating point with high efficiency, and obtain the target mechanical power of the smaller range extender assembly. By optimizing the operating efficiency of the engine and the generator, ensure that the engine and the generator operate in the high-efficiency range, improve the energy utilization efficiency, and reduce energy consumption and emissions.

[0102] S130. Determine the target rotational speed and target torque corresponding to the target mechanical power, and send them to the engine control unit and the generator control unit.

[0103] In practical applications, the target mechanical power is obtained through the formula where n is the target rotational speed and M is the target torque. After the selected target mechanical power, the target rotational speeds and target torques of the engine and the generator corresponding to the abscissa and ordinate can be obtained from Figure 2 . Provide accurate parameters for the control of the rotational speed and torque, and ensure that the engine and the generator operate in the optimal state.

[0104] S140. Control the engine assembly and the generator assembly to output power according to the target rotational speed and target torque.

[0105] In practical applications, send the target rotational speed and target torque to the engine control unit and the generator control unit, and control the engine assembly and the generator assembly to output power according to these parameters. By accurately controlling the operating states of the engine and the generator, ensure that the range extender assembly can stably and efficiently output the required power.

[0106] In the above embodiments, by accurately calculating the required power and optimizing the target output power, ensure that the operating state of the range extender assembly always matches the actual requirements of the lawn mower, optimize the operating state, reduce the mechanical losses of the engine and the generator, and extend the service life of the equipment; it can dynamically adjust the output power according to different working conditions (such as traveling speed, mowing load, battery state, etc.) to adapt to the complex and changeable operating environment. For example, in dense grass or complex terrain, the lawn mower requires higher driving power and mowing power. By dynamically adjusting the output power of the range extender assembly, ensure that the vehicle can operate continuously and stably. In flat terrain or sparse grass, the power requirement of the lawn mower is lower. At this time, the range extender assembly can reduce the output power and reduce energy consumption.

[0107] Based on the above specific embodiments, the corresponding relationship between the required power and the target output power according to the formula specifically includes:

[0108] Compare the required power and the target output power.

[0109] When the battery SOC is greater than the upper threshold, determine the target output power = required power - discharge power of the battery;

[0110] When the battery SOC is between the lower threshold and the upper threshold, determine the target output power = required power;

[0111] When the battery SOC is less than the lower threshold, determine the target output power = required power + charging power of the battery.

[0112] In practical applications, when the power battery needs to be charged, the range extender assembly can dynamically adjust the charging power according to the battery state; when the battery discharges, the range extender assembly can supplement the power to ensure the normal operation of the vehicle.

[0113] Specifically, when the battery SOC is greater than the upper threshold (such as 80%), the target output power = required power - discharge power of the battery, that is, when the battery power exceeds the upper threshold, to prevent overcharging of the battery, the system will reduce the electrical energy extracted from the battery, thereby reducing the discharge power of the battery.

[0114] When the battery SOC is between the lower threshold (such as 50%) and the upper threshold, the target output power = required power. In this range, the battery power is in a normal state, so the target output power is directly equal to the required power, and the battery neither needs additional charging nor needs to reduce discharge.

[0115] When the battery SOC is less than the lower threshold, the target output power = required power + charging power of the battery, that is, when the battery power is lower than the lower threshold, to prevent over-discharge of the battery, the system will increase the charging power of the battery to ensure that the battery power will not be too low.

[0116] It should be noted that SOC refers to the state of charge of the battery, that is, the ratio of the remaining battery power to the total battery capacity, usually expressed as a percentage, and is used to guide functions such as charging, discharging, and energy recovery of electric vehicles.

[0117] In the above embodiments, it can ensure that the battery works within a safe SOC range while meeting the required power of the system. By adjusting the target output power, the charging and discharging process of the battery can be effectively controlled, the service life of the battery can be extended, and the stable operation of the system can be guaranteed.

[0118] Based on the above various specific embodiments, between the preset target mechanical power curve corresponding to the target output power of the range extender assembly and sent to the engine control unit and the generator control unit, it further includes:

[0119] Select multiple target mechanical powers corresponding to the high-efficiency points as alternative target mechanical powers;

[0120] Select the optimal target mechanical power from multiple alternative target mechanical powers according to the overall performance of the lawn mower;

[0121] Determine the optimal target speed and optimal target torque corresponding to the optimal target mechanical power, and send them to the engine control unit and the generator control unit.

[0122] In practical applications, according to the target output power of the range extender assembly, combined with the preset target mechanical power curve, select multiple target mechanical powers with higher efficiency as alternatives. The alternative target mechanical powers are usually located in the high-efficiency working range of the engine to ensure the balance of fuel economy and power output. By presetting multiple high-efficiency working points, the working mode of the range extender is dynamically adjusted according to different working conditions and battery states.

[0123] Among multiple alternative target mechanical powers, power output can be achieved through different combinations of generator speed and generator torque. Preferably, considering factors such as engine thermal efficiency, generator conversion efficiency, generator control unit conversion efficiency, overall machine NVH (noise, vibration, and harshness) performance, and engine emissions, the working conditions of the generator with different output powers can be preselected, and by analyzing the overall machine performance under different target mechanical powers, select the power point with the best performance for the lawn mower as the optimal target mechanical power.

[0124] In a range-extended lawn mower, this control method can significantly improve the operation efficiency and comfort of the equipment. For example, in high-load working conditions, by optimizing the selection of the target mechanical power, it can ensure that the range extender operates in the high-efficiency area while reducing the noise interference to the operator.

[0125] After determining the optimal target mechanical power, according to the working condition preselection table in Table 1, find the corresponding optimal target speed and torque.

[0126] Table 1 Working condition preselection table of the range extender assembly.

[0127]

[0128] It should be noted that the rotor of the generator assembly is connected to the crankshaft of the engine assembly, and the generator speed = engine speed, and the generator torque = engine torque.

[0129] The range extender control unit 3 sends the optimal target speed and optimal target torque to the engine control unit and the generator control unit through the vehicle network. The control unit performs precise control according to the received instructions, adjusts the operating states of the engine and the generator, ensures that the range extender operates under the optimal working conditions, and realizes efficient and stable energy output.

[0130] In the above embodiments, the range extender can operate efficiently, stably, and with low noise under different working conditions, thereby improving the overall performance and user experience of the lawn mower.

[0131] Based on the above specific embodiments, after controlling the engine assembly and the generator assembly to output power according to the target speed and target torque, it further includes:

[0132] Detect the actual output voltage and actual output current of the generator assembly;

[0133] Receive the actual output voltage and actual output current, and use the formula to calculate the actual output power of the range extender assembly, where is the actual output power of the range extender assembly, is the actual output voltage of the generator assembly, is the actual output current of the generator assembly;

[0134] Compare the actual output power with the target output power. When the actual output power is greater than the target output power, reduce the actual output power of the range extender assembly until it is equal to the target output power; when the actual output power is less than the target output power, increase the actual output power of the range extender assembly until it is equal to the target output power.

[0135] In actual application, after controlling the engine assembly and the generator assembly to output power according to the target speed and target torque, the generator control unit detects the actual output voltage and actual output current of the generator assembly. The range extender control unit 3 calculates the actual output power of the range extender assembly through the voltage and current signals reported by the generator control unit, , where is the actual output power of the range extender assembly, is the actual output voltage of the generator assembly, is the actual output current of the generator assembly.

[0136] Compare the calculated actual output power with the target output power, and adjust the output power of the range extender assembly according to the comparison result:

[0137] When the actual output power is greater than the target output power, the range extender control unit 3 appropriately reduces the target speed or target torque to reduce the actual output power of the range extender assembly so that it gradually approaches the target output power and finally equals the target output power.

[0138] When the actual output power is less than the target output power, the range extender control unit 3 appropriately increases the target speed or target torque to increase the actual output power of the range extender assembly so that it gradually approaches the target output power and finally equals the target output power.

[0139] In the above embodiments, the actual output power is monitored in real time. According to the deviation between the actual output power and the target output power, the target torque or the target speed is dynamically adjusted to achieve closed-loop control, ensuring that the range extender assembly always operates in the efficient range and meets the power requirements of the lawn mower.

[0140] Based on the above various specific embodiments, the method for the range extender control unit 3 to control the start of the engine assembly includes:

[0141] Combined with the current temperature and crankshaft position of the engine assembly, calculate the magnitude of the starting target torque required for the current start;

[0142] Send the starting target torque to the generator control unit to control the generator assembly to output torque with the starting target torque, and the rotor of the generator assembly drives the crankshaft of the engine assembly to rotate;

[0143] Monitor the actual speed of the generator assembly, and compare the actual speed with the preset speed. When the actual speed reaches the preset speed, control the engine assembly to start.

[0144] In practical applications, the range extender control unit 3 combines information such as the current temperature and crankshaft position of the engine assembly, calculates the magnitude of the starting target torque required for the current start, and sends a starting target torque request to the generator control unit. By accurately calculating the starting target torque and combining the temperature and crankshaft position information of the engine, the starting process is optimized, and the starting time and energy consumption are reduced. After receiving the request signal, the generator control unit controls the generator assembly to output torque, so that the rotor of the generator assembly drives the crankshaft of the engine assembly to rotate, and reports the generator speed to the range extender control unit 3 in real time. When the generator speed reaches the established speed, the range extender control unit 3 sends a starting instruction to the engine control unit. After receiving the starting instruction, the engine control unit controls the engine fuel injector and ignition coil to work and starts the engine. By monitoring the actual speed of the generator in real time, it is ensured that the engine smoothly switches to the normal operation mode after reaching the preset speed.

[0145] In the above embodiments, there is no need to be equipped with a starting motor, and the engine electric starting function can be realized through the generator system 2 connected to the engine system 1, reducing the structural complexity and cost of the engine.

[0146] Based on the above various specific embodiments, the magnitude of the starting target torque is estimated based on the starting target time, the starting target speed, the friction loss torque, the pumping loss torque, and the compression loss torque. The specific method includes:

[0147] According to the formula Calculate the starting target angular velocity, where n is the starting target speed;

[0148] According to the formula Calculate the starting angular acceleration, where t is the starting target time;

[0149] According to the formula Calculate the starting resultant torque, where I is the moment of inertia;

[0150] According to the formula Calculate the starting target torque, where is the frictional loss torque, is the pumping loss torque, is the compression loss torque.

[0151] The frictional torque refers to the resistance generated by the friction of the engine crankshaft and piston movement and the agitation of engine oil;

[0152] The pumping loss torque refers to the gas suction / discharge resistance that the engine piston needs to overcome during the intake and exhaust strokes;

[0153] The compression torque refers to the gas compression resistance that the engine piston needs to overcome during the compression stroke;

[0154] The temperature of the engine is used to estimate the frictional torque generated due to the change in engine oil viscosity at different temperatures;

[0155] The crankshaft position information of the engine is used to determine the current stroke of the engine, so as to estimate the pumping loss torque and compression torque of the engine.

[0156] In the above embodiment, the range extender control unit 3 can accurately calculate the starting target torque and send it to the generator control unit, which can ensure that the engine can reach the target speed quickly and smoothly during startup, while reducing the energy loss and mechanical shock during the startup process.

[0157] In a specific embodiment, as Figure 6 shown, the range-extended power system provided by the present invention includes an energy distribution unit 10 respectively connected to each motor controller of the lawn mower, a power battery 9 and a range extender that are both bidirectionally connected to the energy distribution unit 10. The energy distribution unit 10 is used to control the power battery 9 to supply electrical energy to the lawn mower when both the discharge power and the power quantity of the power battery 9 meet the working requirements of the lawn mower; when at least one of the discharge power and the power quantity of the power battery 9 does not meet the working requirements of the lawn mower, control the range extender to supply electrical energy to the lawn mower.

[0158] In practical applications, the range-extended power system is applied to a hybrid lawn mower, which also includes a mowing device, a traveling device, and a vehicle body. The traveling device includes a drive wheel, a reduction gearbox 25, a drive motor 24, and a drive motor controller. The mowing device includes a cutter head, a mowing motor 21, and a mowing motor controller 20. The drive motor 24 is connected to the drive wheel through the reduction gearbox 25, and the drive motor 24 controls the rotation of the drive wheel. The drive motor controller is connected to the drive motor 24 to control the rotation speed and forward / reverse rotation of the drive motor 24. The mowing motor 21 is directly connected to the cutter head to complete the mowing operation. The mowing motor controller 20 is connected to the mowing motor 21 to control the rotation speed and rotation direction of the mowing motor 21.

[0159] The range-extended power system includes an energy distribution unit 10, a power battery 9, and a range extender. The range extender includes an engine system 1, a generator system 2, and a range extender control unit 3. The engine system 1 is connected to the generator system 2, and the engine system 1 provides mechanical power to the generator system 2. The generator control unit converts the three-phase alternating current of the generator assembly into direct current, which can supply power to the drive motor controller, the mowing motor controller 20, and the vehicle battery.

[0160] The power battery 9 is bidirectionally connected to the drive motor controller, the mowing motor controller 20, and the generator control unit through the energy distribution unit 10, and can supply power to the drive motor controller and the mowing motor controller 20. The charging and discharging of the power battery 9 are determined by the output power of the generator control unit and the required power of the drive motor controller and the mowing motor controller 20.

[0161] The range-extended power system is divided into two driving modes: pure electric mode and range-extended mode. Both the power battery 9 and the range extender are bidirectionally connected to the energy distribution unit 10, and the energy distribution unit 10 is used to distribute the energy flow between the power battery 9 and the range extender.

[0162] When both the discharge power and the power level of the power battery 9 can meet the working requirements of the lawn mower, the energy distribution unit 10 controls the power battery 9 to supply electrical energy to the lawn mower. At this time, the lawn mower is completely driven by the battery.

[0163] When at least one of the discharge power or the power level of the power battery 9 does not meet the working requirements of the lawn mower, the energy distribution unit 10 controls the range extender to start, and the range extender supplies electrical energy to the lawn mower. The range extender can directly drive the drive motor 24 and the mowing motor 21 without passing through the power battery 9, can start immediately and enter the normal working state, reducing the energy transfer loss; the engine is decoupled from the transmission system, and the engine can operate in the optimal region with precise control.

[0164] Applying the technical solution provided by the embodiments of the present invention, the energy distribution unit 10 dynamically distributes the output power of the power battery 9 and the range extender according to the SOC (state of charge) of the power battery 9 and the actual power demand of the lawn mower. When the battery power is lower than the preset threshold, the range extender starts and charges the battery, while providing power for the lawn mower. The range-extended power system combines the high efficiency of pure electric drive and the endurance advantage of fuel power generation, optimizes the energy distribution, has flexible power switching, and achieves efficient, energy-saving and low-noise operation effects. It is especially suitable for lawn mowers that need to run for a long time and have limited charging conditions, and can continue to work by fuel power generation when the battery power is insufficient.

[0165] Based on the above various specific embodiments, when the discharge power of the power battery 9 is greater than the working power of the lawn mower and the power of the power battery 9 is greater than the threshold, the power battery 9 is controlled to supply electrical energy to the lawn mower.

[0166] In practical applications, the energy distribution unit 10 real-time monitors the SOC (state of charge) and discharge power of the power battery 9. If both the discharge power and the power of the power battery 9 meet the working requirements of the lawn mower, that is, the discharge power of the power battery 9 is greater than the working power of the lawn mower and the SOC value is greater than the preset threshold, it enters the pure electric mode, and the energy distribution unit 10 controls the power battery 9 to supply electrical energy to the lawn mower. At the same time, the energy distribution unit 10 will dynamically adjust the discharge power of the battery according to the actual power demand of the lawn mower to ensure that the battery operates within a safe range.

[0167] If the above conditions are not met, that is, the discharge power of the power battery 9 is less than the working power of the lawn mower or the SOC value of the power battery 9 is lower than the preset threshold, it switches to the range-extended mode, and the energy distribution unit 10 controls the range extender to start, and the range extender supplies electrical energy to the lawn mower and charges the power battery 9 at the same time.

[0168] The discharge power of the power battery 9 is greater than the working power of the lawn mower, that is, the battery has sufficient power output to meet the immediate needs of the lawn mower and will not cause performance degradation due to insufficient power.

[0169] The power of the power battery 9 is greater than the preset threshold (such as the SOC value, usually 30%-50%), to avoid continuous discharge when the battery power is too low, resulting in deep discharge of the battery and affecting the battery life. At the same time, when the power is lower than the threshold, the system will switch to the range-extended mode to ensure the continuous operation of the lawn mower.

[0170] In the above embodiments, the energy distribution unit 10 dynamically switches the power source according to the battery state and the working requirements, ensuring the continuous operation of the lawn mower and extending the battery life at the same time.

[0171] Based on the above specific embodiments, when at least one of the discharge power and the power level of the power battery 9 does not meet the working requirements of the lawn mower, the energy distribution unit 10 controls the range extender to supply electrical energy to the lawn mower. Specifically, it is divided into the following three cases:

[0172] In the first case, the discharge power of the power battery 9 is greater than the working power of the lawn mower, but the power level of the power battery 9 is lower than the threshold value. The range extender is controlled to supply electrical energy to both the lawn mower and the power battery 9 simultaneously. At this time, the range extender provides power for the lawn mower and charges the power battery 9 at the same time to maintain the power level of the battery and avoid deep discharge. While ensuring the normal operation of the lawn mower, the battery life is extended.

[0173] In the second case, the discharge power of the power battery 9 is less than the working power of the lawn mower, but the power level of the power battery 9 is higher than the threshold value. The range extender is controlled to supply electrical energy to the lawn mower alone or the range extender and the power battery 9 are controlled to supply electrical energy to the lawn mower simultaneously. When the battery has sufficient power but insufficient power, the range extender directly provides power to ensure the power demand of the lawn mower; if necessary, the power battery 9 can assist in providing part of the power to reduce the burden on the range extender, optimize the system efficiency, flexibly allocate the power source, and ensure the performance and efficiency of the lawn mower.

[0174] In the third case, the discharge power of the power battery 9 is less than the working power of the lawn mower, and the power level of the power battery 9 is lower than the threshold value. The range extender is controlled to supply electrical energy to the lawn mower alone or the range extender is controlled to supply electrical energy to both the lawn mower and the power battery 9 simultaneously. In the case where both the battery power and the power are insufficient, the range extender gives priority to meeting the power demand of the lawn mower; at the same time, it charges the power battery 9 to maintain the continuous operation of the system, ensuring that the lawn mower can still work normally under extreme conditions and avoiding equipment shutdown due to the exhaustion of the battery power.

[0175] In the above embodiments, the energy distribution unit 10 dynamically adjusts the distribution of the power source according to the real-time state (power and power level) of the power battery 9 and the working requirements of the lawn mower. Under different working conditions, the system gives priority to meeting the power demand of the lawn mower, while taking into account the power level maintenance and charging requirements of the power battery 9.

[0176] Based on the above specific embodiments, the energy distribution unit 10 includes:

[0177] A high power level module, which is used to control the range extender to supply electrical energy to the lawn mower when the power level of the power battery 9 is lower than the threshold value and higher than the first preset value;

[0178] A low power level module, which is used to control the range extender to supply electrical energy to both the lawn mower and the power battery 9 simultaneously when the power level of the power battery 9 is lower than the first preset value and higher than the second preset value.

[0179] In practical applications, the energy distribution unit 10 includes a high-battery module and a low-battery module, and these two modules execute different control strategies according to the battery level of the power battery 9.

[0180] The battery level of the power battery 9 is lower than the threshold (for example, the SOC threshold is 30%), but higher than the first preset value (for example, the SOC is 20%). At this time, although the battery level of the power battery 9 is insufficient, there is still a certain amount of remaining power. In order to preferentially meet the power demand of the lawn mower, the high-battery module controls the range extender to directly supply electric energy to the lawn mower to ensure the normal operation of the device. And since the battery level of the power battery 9 is still higher than the first preset value, the power battery 9 is not charged, avoiding unnecessary energy waste and battery life loss.

[0181] The battery level of the power battery 9 is lower than the first preset value (for example, the SOC is 20%), but higher than the second preset value (for example, the SOC is 10%). At this time, the battery level of the power battery 9 is low, and it is necessary to simultaneously meet the power demand of the lawn mower and the charging demand of the power battery 9. The low-battery module controls the range extender to supply electric energy to the lawn mower and charge the power battery 9, better balancing the power and battery level demands to ensure the continuous operation of the device and the health of the battery.

[0182] In the above embodiments, through the division of labor between the high-battery module and the low-battery module, the energy distribution unit 10 can dynamically adjust the working mode of the range extender according to the battery level of the power battery 9, and manage the energy distribution more precisely.

[0183] Based on the above specific embodiments, when the range extender and the power battery 9 supply electric energy to the lawn mower at the same time, the power battery 9 provides all its power to the lawn mower, and the range extender provides the remaining required power.

[0184] In practical applications, when the discharge power of the power battery 9 is less than the working power of the lawn mower and the battery level of the power battery 9 is higher than the threshold, the range extender and the power battery 9 are controlled to supply electric energy to the lawn mower at the same time, and the power battery 9 provides all its available power to the lawn mower. The range extender provides the remaining required power to meet the total power demand of the lawn mower.

[0185] In the above embodiments, even when the discharge power of the battery is low, the power battery 9 can still provide part of the power, and the range extender provides the remaining required power. Not only is the power demand of the lawn mower met, but also the energy utilization efficiency is optimized.

[0186] Based on the above specific embodiments, the lawn mower includes a mowing device and a traveling device. The mowing motor controller 20 of the mowing device and the drive motor controller of the traveling device are both connected to the energy distribution unit 10. The energy distribution unit 10 includes:

[0187] A power prediction module is used to calculate the required mowing power and traveling power respectively during the operation of the lawn mower.

[0188] A target power module is connected to the power prediction device and is used to determine the target power at which the range extender supplies electrical energy to both the lawn mower and the power battery 9 simultaneously. The target power exceeds the sum of the mowing power and the traveling power.

[0189] A power distribution device is connected to the target power module and is used to control the range extender to first supply electrical energy to the lawn mower, and after the power supply to the lawn mower is completed, supply the remaining electrical energy to the power battery 9 after a set delay time.

[0190] In practical applications, the mowing device is controlled by the mowing motor controller 20 for mowing operations. The traveling device is controlled by the drive motor controller and is responsible for the movement of the lawn mower. The energy distribution unit 10 is connected to the mowing motor controller 20 and the drive motor controller and is used for energy distribution and management. The power battery 9 supplies electrical energy to the lawn mower. When the power of the power battery 9 is insufficient, the range extender provides additional electrical energy.

[0191] The power prediction module calculates the mowing power and the traveling power in real time according to the operating state of the lawn mower (such as mowing speed, traveling speed, load condition, etc.).

[0192] The target power module calculates the total power that the range extender needs to provide according to the mowing power and the traveling power provided by the power prediction module. Target power = mowing power + traveling power + charging power. The target power exceeds the sum of the mowing power and the traveling power to ensure that the system has enough redundant power to charge the power battery 9.

[0193] The power distribution device controls the range extender to give priority to supplying electrical energy to the mowing device and the traveling device according to the instruction of the target power module to ensure the normal operation of the lawn mower. After the power demand of the lawn mower is met, the power distribution device will delay for a set time (such as several seconds to dozens of seconds), and then supply the remaining electrical energy to the power battery 9 for charging. Delayed charging can avoid frequent switching of the charging state when the power demand of the lawn mower fluctuates, improving the stability and reliability of the system.

[0194] In the above embodiments, when the power demand of the lawn mower changes, the power distribution device will adjust the output power of the range extender in real time and dynamically adjust the power distribution to ensure the efficient operation of the system. By accurately calculating and dynamically distributing power, the system can optimize the energy utilization efficiency and reduce energy waste. The range extender gives priority to meeting the power demand of the lawn mower to ensure the continuity of mowing operations.

[0195] Based on the above various specific embodiments, the energy distribution unit 10 includes:

[0196] A forced charging module is used to control the charging of the power battery 9 when the mowing vehicle is in an unloaded operation and the power of the power battery 9 is lower than the low charging value.

[0197] A forced power-off module is used to control the power battery 9 to stop providing electrical energy when the mowing vehicle is in an unloaded operation and the power of the power battery 9 is lower than the low power-off value.

[0198] In practical applications, the energy distribution unit 10 includes a forced charging module and a forced power-off module. When the mowing vehicle is in an unloaded state or running at a low load, that is, when the mowing vehicle has no power demand, if the power of the power battery 9 is lower than the preset low charging value, the forced charging module will control the power battery 9 to be connected to the power supply to charge the power battery 9, avoiding excessive consumption of the battery power due to long-term low-load operation and extending the battery life.

[0199] By monitoring the power of the power battery 9, when the mowing vehicle is in an unloaded state and the power of the power battery 9 is lower than the preset low power-off value, the forced power-off module automatically cuts off the output of the battery to prevent over-discharge of the battery, thereby protecting the battery and avoiding battery damage caused by deep discharge.

[0200] In the above embodiments, through the forced charging and power-off modules, the battery power and vehicle working conditions are monitored in real time, avoiding deep discharge and overcharging, and effectively extending the service life of the power battery 9.

[0201] Based on the above various specific embodiments, it further includes a battery 22 connected to the energy distribution unit 10 through a power conversion device 23. The energy distribution unit 10 includes:

[0202] A power detection module is used to detect the power in the battery 22.

[0203] A charging module is connected to the power detection module and is used to connect the power conversion device 23 to charge the battery 22 when the power in the battery 22 is lower than the set value.

[0204] In practical applications, the energy distribution unit 10 includes a power detection and charging module. The energy distribution unit 10 not only manages the energy distribution of the power battery 9 and the range extender, but also is connected to the battery 22 through the power conversion device 23 to realize the power detection and charging control of the battery 22.

[0205] The power detection module monitors the power of the battery 22 in real time. Specifically, the remaining power of the battery 22 can be calculated by detecting parameters such as the voltage, current and temperature of the battery 22. The charging module is connected to the power detection module. When the power of the battery 22 is lower than the set value, the charging module is triggered to charge the battery 22 through the power conversion device 23. During the charging process, the charging module monitors the state of the battery 22 in real time to prevent overcharging or overcurrent.

[0206] The power conversion device 23 is a key component connecting the energy distribution unit 10 and the battery 22, which is used to convert the electric energy output by the power battery 9 or the range extender into a voltage suitable for charging the battery 22. When the battery 22 is charging, the power is reasonably distributed to ensure the normal operation of other devices of the lawn mower (such as the mowing device and the traveling device).

[0207] In the above embodiment, the energy distribution unit 10 realizes the intelligent management and efficient charging of the battery 22 according to the battery power of the battery 22 and the real-time demand of the lawn mower.

[0208] Based on the above various specific embodiments, when the mowing motor 21 works, its power is jointly provided by the range extender and the power battery 9 through the energy distribution unit 10 via the mowing motor controller 20; when the mowing motor 21 stops working, its residual kinetic energy is converted into electric energy through the mowing motor controller 20 and stored in the power battery 9 through the energy distribution unit 10.

[0209] In practical applications, when the mowing motor 21 works, the power demand of the mowing motor 21 is transmitted to the energy distribution unit 10 through the mowing motor controller 20. The energy distribution unit 10 coordinates the range extender and the power battery 9 to jointly provide the required electric energy according to the actual power demand of the mowing motor 21. The power battery 9 preferentially provides part of the power to meet the immediate demand. The range extender supplements the remaining power that the power battery 9 cannot meet to ensure that the power demand of the mowing motor 21 is fully met. The energy distribution unit 10 monitors the battery power of the power battery 9 and the output status of the range extender in real time and dynamically adjusts the power distribution between the two to optimize the energy utilization efficiency.

[0210] When the mowing motor 21 stops working, its residual kinetic energy is converted into electric energy through the mowing motor controller 20. The converted electric energy is transmitted to the power battery 9 through the energy distribution unit 10 to charge the battery, realizing energy recovery. The charging module in the energy distribution unit 10 can also monitor the battery power and charging status of the power battery 9 to ensure the safety and efficiency of the charging process and avoid overcharging.

[0211] It should be noted that the above embodiment is described with the cutter head being idle. Similarly, when the drive motor 24 stops working (such as decelerating or going downhill), its residual kinetic energy is converted into electric energy through the drive motor controller. The converted electric energy is transmitted to the power battery 9 through the energy distribution unit 10 to charge the battery, and energy recovery can also be realized.

[0212] In the above embodiment, by recovering the residual kinetic energy when the mowing motor 21 and the drive motor 24 stop working, converting it into electric energy and storing it in the power battery 9, not only the energy utilization efficiency of the system is improved, but also the service life of the power battery 9 is extended.

[0213] The present invention also provides a flowchart of a control method for an extended-range power system applying any one of the above, including the steps:

[0214] Obtain the discharge power of the power battery 9, the working power of the lawn mower, and the power battery 9 power;

[0215] When the discharge power of the power battery 9 is greater than the working power of the lawn mower and the power battery 9 power is greater than the threshold value, control the power battery 9 to supply electric energy to the lawn mower;

[0216] When the discharge power of the power battery 9 is greater than the working power of the lawn mower and the power battery 9 power is lower than the threshold value, control the range extender to supply electric energy to the lawn mower and the power battery 9;

[0217] When the discharge power of the power battery 9 is less than the working power of the lawn mower and the power battery 9 power is greater than the threshold value, control the range extender to supply electric energy to the lawn mower or control the range extender and the power battery 9 to supply electric energy to the lawn mower simultaneously;

[0218] When the discharge power of the power battery 9 is less than the working power of the lawn mower operation and the power battery 9 power is lower than the threshold value, control the range extender to supply electric energy to the lawn mower or control the range extender to supply electric energy to the lawn mower and the power battery 9.

[0219] By real-time monitoring the discharge power, working power, and power of the power battery 9, flexibly adjust the power supply mode according to different working loads and battery states, and select the most suitable power supply mode. The intervention of the range extender can provide additional electric energy support when the battery power is insufficient, avoid over-discharge of the power battery 9, reduce the deep charge and discharge cycles of the battery, extend the battery life, and extend the endurance mileage of the lawn mower.

[0220] In a specific embodiment, such as Figure 7 , a balance device for the generator and the engine, the crankshaft 27 of the engine is connected to the motor shaft of the generator, including a flywheel 35 installed at the connection end of the crankshaft 27 and a rotor 30 connected to the motor shaft. The motor shaft is provided with a connection hole at one end close to the crankshaft 27, the motor shaft is concentric with the connection hole, and the connection end of the crankshaft 27 is connected into the connection hole and the crankshaft 27 and the motor shaft are rigidly connected.

[0221] The connection between the engine and the generator adopts a rigid connection method. The flywheel 35 and the rotor 30 play the role of "dual flywheels 35" to fully balance the rotational inertia on the engine crankshaft 27 through the mutual matching between the engine flywheel 35 and the generator rotor 30, reduce the torque fluctuation on the engine, improve the anti-torsion ability between the generator and the engine, and make the engine output torque more stable.

[0222] Moreover, a connection hole is provided at one end of the motor shaft close to the crankshaft 27. The center line of the motor shaft and the center line of the connection hole are on the same straight line, that is, the motor shaft and the crankshaft 27 are on the same straight line. The motor shaft is directly connected to the engine crankshaft 27, ensuring high rotational speed and torque transmission efficiency and reducing space occupation. The connection end of the crankshaft 27 is connected within the connection hole, that is, the crankshaft 27 and the motor shaft are connected inside the motor shaft. This design can reduce the axial space occupation of the motor shaft, make the structure more compact, greatly improve the total power density, and reduce the production and manufacturing costs at the same time.

[0223] Based on the above various specific embodiments, the connection hole is a through hole penetrating the length of the motor shaft. The balancing device further includes a fastener 36 connected to the other end inside the connection hole. A threaded hole is provided on the connection end face of the crankshaft 27. The end of the fastener 36 is threadedly connected to the threaded hole. The head of the fastener 36 abuts against the rear end face of the motor shaft. The helix direction of the threaded hole is opposite to the rotation direction of the motor shaft.

[0224] In the above embodiments, the motor shaft is a hollow shaft. The fastener 36 is used to achieve the rigid connection between the engine crankshaft 27 and the motor shaft. Cooperating with the flywheel 35 at the front end of the crankshaft 27, the engine crankshaft 27 has high anti-torsion ability; by arranging a connection part inside the motor shaft, the axial space occupation of the motor shaft can be reduced, making the whole device more compact; the connection method is simple, the spline and the generator connection end bearing are cancelled, the number of components and manufacturing complexity are reduced, and the cost is lowered.

[0225] Based on the above various specific embodiments, the diameter of the fastener 36 is smaller than the diameter of the connection end of the crankshaft 27. The through hole is a stepped hole including a large-diameter hole and a small-diameter hole. The crankshaft 27 is connected to the large-diameter hole, and the fastener 36 is connected to the small-diameter hole. The end of the fastener 36 is threadedly connected to the threaded hole on the end face of the crankshaft 27, which not only connects the crankshaft 27 and the motor shaft with the fastener 36, but also provides better structural stability and strength. The small-diameter hole is in clearance fit with the fastener 36 to ensure the stability and safety of the fastener 36, and also meet the requirements of assembly and operation.

[0226] Based on the above various specific embodiments, the large-diameter hole is a tapered hole with an outward-opening mouth. The connection end of the crankshaft 27 is a tapered shaft. The connection end of the crankshaft 27 and the tapered surface of the large-diameter hole are in tapered surface fit. The torque transmission of the tapered surface connection is mainly through the static friction force generated by the combined pressure between the connection surfaces, that is, the pre-tightening force of the fastener 36 transmits torque through the friction force of the mating surface of the tapered hole and the tapered shaft; the tapered surface fit can increase the contact area between the motor shaft and the crankshaft 27, achieve high-strength connection, cooperate with the connection of the motor shaft and the crankshaft 27 by the fastener 36 and the flywheel 35, and has high anti-torsion ability; the bearing structure at the generator connection end is cancelled, and the structure is simple.

[0227] On the basis of the above respective specific embodiments, an intermediate straight hole is provided between the small-diameter hole and the tapered hole. The diameter of the intermediate straight hole is equal to the small-end diameter of the tapered hole. The intermediate straight hole can ensure smoother tapered fit assembly and higher fitting accuracy. When machining the tapered hole, a straight hole can be bored first according to the small-end diameter with a set allowance remaining, which can eliminate the machining of the stepped hole of the tapered hole, shorten the cutting time, and improve the production efficiency.

[0228] On the basis of the above respective specific embodiments, a counterbore connected to the small-diameter hole is provided on the rear end face of the motor shaft, and the bolt head of the fastener 36 is placed inside the counterbore. The counterbore can make the fastener 36 flush with or lower than the rear end face of the motor shaft. The fastener 36 is installed inside the motor shaft, reducing the protrusion on the appearance of the fastener 36. This is not only aesthetically pleasing but also improves the compactness of the assembly position.

[0229] On the basis of the above respective specific embodiments, the connecting hole is an internal threaded hole, and the connecting end of the crankshaft 27 has an external thread. The connecting end of the crankshaft 27 is threadedly connected to the connecting hole. In cooperation with the connection of the fastener 36 to the threaded hole of the crankshaft 27, the crankshaft 27 and the motor shaft are connected, realizing the double connection of the crankshaft 27 and the motor shaft, strengthening the connection strength between the motor shaft and the crankshaft 27, and having a relatively high anti-torsion ability.

[0230] On the basis of the above respective specific embodiments, the connecting hole and the connecting end of the crankshaft 27 are in interference fit. When there is a certain fastening force between the connecting hole and the crankshaft 27, the stability and load-bearing capacity of the connection can be ensured. In cooperation with the threaded connection of the connecting end of the crankshaft 27 to the connecting hole and the connection of the fastener 36 to the threaded hole of the crankshaft 27, the crankshaft 27 and the motor shaft are connected, realizing the multiple connection of the crankshaft 27 and the motor shaft, strengthening the connection strength between the motor shaft and the crankshaft 27, and having a relatively high anti-torsion ability.

[0231] On the basis of the above respective specific embodiments, the connection length between the connecting end of the crankshaft 27 and the connecting hole accounts for one-third to one-half of the length of the motor shaft. The longer connection length between the connecting end of the crankshaft 27 and the connecting hole can provide a larger contact area, thereby more effectively transmitting torque and ensuring a relatively high power transmission efficiency between the generator and the crankshaft 27. The longer the connection length of the interference fit, the more contact points there are, and the higher the reliability of the fit, thus improving the overall stability of the connection. It can provide better compensation and reduce the fit problems caused by temperature changes. It can increase the stiffness and strength of the connection and reduce the risk of deformation or damage caused by external forces.

[0232] In a specific embodiment, as Figure 8As shown in the figure, the pressure balance device of the range extender of the hybrid lawn mower includes a crankcase 26 with a rear port, a motor chamber 29 with a front port, and an intermediate end cover 28 whose two end faces are hermetically connected to the rear port of the crankcase 26 and the front port of the motor chamber 29 respectively. The intermediate end cover 28 has a connection hole communicating the crankcase 26 and the motor chamber 29. The crankshaft 27 in the crankcase 26 passes through the connection hole and is connected to the rotor shaft of the motor chamber 29. The connection hole is connected with an oil seal 34 to seal the engine oil inside the crankcase 26. It also includes a pressure balance device for making the air pressure in the motor chamber 29 equal to the air pressure in the crankcase 26.

[0233] The crankcase 26 is designed with a ventilation system, and its internal air pressure is communicated with the atmosphere, and its internal air pressure is equivalent to the atmospheric pressure. If the motor chamber 29 is in a completely sealed state, during the working process, the volume of the gas in the motor chamber 29 changes due to the influence of temperature, which in turn causes a change in air pressure. This causes a pressure difference between the two sides of the oil seal 34, thereby destroying the working environment of the oil seal 34 and generating a risk of engine oil leakage. Therefore, a pressure balance device is added to the motor chamber 29 to make the inside of the motor chamber 29 communicate with the outside atmosphere. When the air pressure in the motor chamber 29 is greater than the atmospheric pressure, the excess gas is discharged through the pressure balance device. When the air pressure in the motor chamber 29 is less than the atmospheric pressure, air enters the motor chamber 29 through the pressure balance device, balancing the air pressure inside the motor chamber 29 and the outside environment, making the air pressure in the motor chamber 29 equal to the air pressure in the crankcase 26, and playing a role in protecting the oil seal 34.

[0234] For the pressure balance device of the range extender provided by the present invention, the rear port of the crankcase 26 and the front port of the motor chamber 29 share an intermediate end cover 28, canceling the front end cover of the generator, simplifying the structure, making the connection and assembly more convenient, reducing the weight of the range extender, and lowering the cost. At the same time, on the premise of meeting the working requirements of the engine oil seal 34 and the airtightness of the stator 31 and rotor 30 chambers of the generator, a pressure balance device is added to balance the air pressure inside the motor chamber 29 and the outside environment, thereby avoiding the oil leakage problem of the engine oil seal 34 caused by the change in air pressure in the motor chamber 29 and improving the performance and reliability of the range extender.

[0235] On the basis of the above various specific embodiments, the pressure balance device includes:

[0236] A pressure sensor for detecting the air pressure in the motor chamber 29;

[0237] A pressure balance mechanism connected to the pressure sensor and used to control the communication between the outside atmosphere and the motor chamber 29 when the detected air pressure in the motor chamber 29 is not equal to the atmospheric pressure so that the outside atmospheric pressure is equal to the air pressure in the motor chamber 29.

[0238] The pressure balance device detects the air pressure difference through a pressure sensor and controls the gas flow through a pressure balance mechanism connected thereto. The air pressure balance device can respond to the air pressure difference in a timely manner, so that the air pressure inside and outside the closed space of the motor chamber 29 is kept balanced, that is, the air pressure in the motor chamber 29 is balanced with the air pressure in the crankcase 26, avoiding the oil leakage problem caused by the change of the air pressure in the motor chamber 29 for the engine oil seal 34, and ensuring the safe and stable operation of the range extender.

[0239] Based on the above specific embodiments, the pressure balance mechanism includes:

[0240] A calculation unit for calculating the difference information between the external atmospheric pressure and the current air pressure in the motor chamber 29;

[0241] A pressure balance unit connected to the calculation unit for controlling the ventilation direction and ventilation duration between the external atmosphere and the motor chamber 29 according to the difference information calculated by the calculation unit.

[0242] When the air pressure in the motor chamber 29 is not equal to the external atmospheric pressure, the pressure balance unit will control the flow direction and opening degree of the valve, so that the air pressure in the motor chamber 29 is balanced with the external atmospheric pressure. Through the collaborative work of the calculation unit and the pressure balance unit, the pressure balance mechanism can accurately control the pressure balance between the motor chamber 29 and the external atmosphere to maintain the stability of the internal environment of the range extender and the normal operation of the equipment.

[0243] Based on the above specific embodiments, a through hole is provided on the rear end cover 32 of the motor chamber 29. The pressure balance unit includes a waterproof breathable membrane 33 installed at the through hole. The waterproof breathable membrane 33 has membrane pores that can pass gas molecules and isolate liquid molecules, achieving the dual effects of allowing gas molecules to pass through while preventing liquid molecules, thereby achieving pressure balance and waterproof and breathable effects, ensuring that the air pressure in the motor chamber 29 is balanced with the atmospheric pressure in real time, and preventing the oil seal 34 from moving due to air pressure changes.

[0244] Based on the above specific embodiments, a housing is provided outside the waterproof breathable membrane 33. Multiple rings of annular grooves are provided on the outer wall of the housing, and sealing rings are provided in the annular grooves. The housing is connected to the through hole through the sealing ring, ensuring the sealing between the housing and the through hole, and preventing liquid and large particle substances from passing through the gap between the housing and the through hole;

[0245] The housing is in a stepped shape. The waterproof breathable membrane 33 is arranged at the large diameter section, and the annular groove is arranged at the small diameter section. The small diameter section is inserted into the through hole and the stepped surface abuts against the end surface of the rear end cover 32, ensuring the tight fit between the housing and the rear end cover 32 and enhancing the stability and sealing of the overall structure.

[0246] Based on the above specific embodiments, the pressure balance unit includes a two-way control valve installed at the through-hole, which is used to control the opening of the through-hole when the air pressure in the motor chamber 29 detected is not equal to the atmospheric pressure. The two-way control valve can allow gas molecules to pass through and isolate liquid molecules. This control valve can automatically open or close when the pressure difference exceeds a preset range, thereby adjusting the pressure balance between the motor chamber 29 and the outside atmospheric pressure, and can quickly respond to pressure changes and close the control valve after the pressure is balanced to maintain the airtightness of the chamber.

[0247] In a preferred embodiment, the two-way control valve and the waterproof breathable membrane 33 can be installed in parallel at the through-hole. When the air pressure in the motor chamber 29 is not equal to the outside atmospheric pressure and rapid adjustment is required, the two-way control valve will automatically open or close according to the signal of the pressure sensor to control the inflow or outflow of gas. The two-way control valve provides the ability to respond quickly and can balance the pressure rapidly in extreme cases; at the same time, the waterproof breathable membrane 33 provides a continuous breathable function, allowing gas molecules to pass through to maintain the pressure balance in the chamber, reducing the dependence on the control valve, reducing energy consumption, and achieving more precise pressure control and protection.

[0248] The combination of the two-way control valve and the waterproof breathable membrane 33 combines active control and passive ventilation, providing a more reliable pressure balance method with high efficiency, flexibility and reliability.

[0249] Based on the above specific embodiments, it further includes a seal detection device for detecting whether the oil seal 34 moves relative to the middle end cover 28. When the seal detection device detects that the oil seal 34 moves due to the change of the internal air pressure in the motor chamber 29, maintenance or replacement can be carried out in time to ensure the airtightness and reliability of the range extender.

[0250] Based on the above specific embodiments, the seal detection device includes:

[0251] A position sensor for detecting the moving direction and moving distance of the oil seal 34 relative to the middle end cover 28;

[0252] A seal reset mechanism connected to the position sensor and used to control the pressure difference between the air pressure in the motor chamber 29 and the air pressure in the crankcase 26 according to the moving direction and moving distance to drive the oil seal 34 to move reversely and reset. By changing the pressure difference, a reverse force is generated, and sufficient reverse force can push the oil seal 34 to move reversely to return it to the correct position, thereby restoring the sealing performance.

[0253] Based on the above specific embodiments, the seal reset mechanism includes:

[0254] An information storage unit for storing the corresponding relationship between the distance required for the oil seal 34 to reset and the pressure difference between the motor chamber 29 and the crankcase 26;

[0255] A sealing and resetting unit connected to the information storage unit and used to control the pressure difference between the air pressure in the motor chamber 29 and the air pressure in the crankcase 26 according to the corresponding relationship between the preset moving distance and the pressure difference value, so as to drive the oil seal 34 to move reversely and reset.

[0256] Through the automatic reset function, the position deviation of the oil seal 34 can be corrected in time, potential failures caused by poor sealing can be reduced, and the reliability and service life of the range extender can be improved; manual intervention is reduced, and the automation degree of the system is improved.

[0257] On the basis of each of the above specific embodiments, it further includes a reminder device connected to the pressure balance device and the seal detection device. The reminder device is used to give an alarm prompt when it is detected that the air pressure in the motor chamber 29 is not equal to the atmospheric pressure or the oil seal 34 moves relative to the middle end cover 28.

[0258] The reminder device can reduce equipment failures caused by air pressure imbalance or sealing problems, and improve the reliability and safety of the equipment. Through timely reminder, potential serious problems can be avoided, and maintenance costs and downtime can be reduced.

[0259] In a specific embodiment, as Figure 9 shown, the water-cooled motor of the hybrid lawn mower includes an inner water jacket 19 and an outer water jacket 17 which are sleeved and connected. A sealed cavity is formed between the inner water jacket 19 and the outer water jacket 17. The outer water jacket 17 is connected with a water inlet nozzle 12 and a water outlet nozzle 13 communicating with the cavity. The outer water jacket 17 is provided with a water inlet 15 and a water outlet 16 corresponding to the water inlet nozzle 12 and the water outlet nozzle 13; it further includes a water inlet and outlet dividing member 14 arranged in the cavity. The water inlet and outlet dividing member 14 divides the water inlet nozzle 12 and the water outlet nozzle 13 in the circumferential direction, so that after the cooling water flows into the cavity from the water inlet nozzle 12, it flows circumferentially along the side away from the water inlet and outlet dividing member 14 and flows out from the water outlet nozzle 13.

[0260] The cooling water circulation of the inner water jacket 19 and the outer water jacket 17 of the motor, combined with the cooling of the motor controller bottom plate by water cooling, has higher heat dissipation efficiency, realizes the efficient cooling of the motor and its controller bottom plate, can control the motor temperature within a reasonable range, keeps the whole machine in a suitable working environment temperature, keeps the whole machine running in a suitable working environment temperature, reduces the failures of the motor caused by high temperature, and extends the service life.

[0261] Based on the above various specific embodiments, the water inlet and outlet dividing member 14 is disposed in the groove. Both ends of the water inlet and outlet dividing member 14 are connected to both ends of the groove. The top surface of the groove and the top surface of the water inlet and outlet dividing member 14 are in contact with the inner wall of the outer water jacket 17. The axial direction of the cavity is completely blocked, preventing the coolant from flowing on both sides of the water inlet and outlet dividing member 14, ensuring the unidirectional flow of the coolant, and improving the drainage and guiding property of the coolant. After the cooling water flows into the cavity from the water inlet nozzle 12, due to the blocking effect of the water inlet and outlet dividing member 14, it can only flow circumferentially along the side away from the water inlet and outlet dividing member 14. This design of unidirectional flow helps to ensure the uniform cooling effect of the entire motor and avoids the problem of uneven cooling effect that may be caused by the bidirectional flow of the coolant. The coolant can perform heat exchange more effectively when flowing through the motor because the coolant is forced to flow around the entire cavity once, thereby improving the cooling efficiency and uniformity.

[0262] Based on the above various specific embodiments, the groove is an annular groove, and the water inlet and outlet dividing member 14 is connected in the annular groove. Preferably, the water inlet and outlet dividing member 14 is welded to the inner water jacket 19, and the water inlet and outlet dividing member 14 is connected to the outer water jacket 17 through a sealing ring, simplifying the structure of the water-cooled motor and making processing and maintenance easier. The combined use of the annular groove and the water inlet and outlet dividing member 14 reduces complex pipelines and connections, lowering the manufacturing cost and maintenance difficulty.

[0263] Based on the above various specific embodiments, the groove is a non-through groove, and the circumferential blockage of the non-through groove forms the water inlet and outlet dividing member 14. The design of the non-through groove is relatively simple and easy to process. This structure not only improves the cooling efficiency but also simplifies the manufacturing process and reduces the cost. Through the design of the non-through groove and the water inlet and outlet dividing member 14, the flow efficiency and uniformity of the coolant can be improved; the bidirectional flow of the coolant is prevented, ensuring that the coolant can fully contact the heat-generating part of the generator, thereby improving the cooling effect.

[0264] Based on the above various specific embodiments, the side edges of the water inlet and outlet dividing member 14 opposite in the circumferential direction are curved edges with concave and convex parts, such as S-shaped. At the water inlet nozzle 12 and the water outlet nozzle 13, the amount of coolant is relatively large. The smooth curved edges provide a smooth guiding and drainage channel for the coolant, reducing the flow resistance, preventing the coolant from accumulating at the water inlet nozzle 12 and the water outlet nozzle 13, facilitating the inflow and outflow of the coolant, ensuring the uniform distribution of the coolant during the flow process, and optimizing the flow characteristics of the coolant.

[0265] Based on the above specific embodiments, the inlet and outlet nozzles 13 are respectively arranged in the recesses on both sides of the inlet and outlet water dividing member 14, which can optimize the space utilization and make the entire cooling system more compact; it can make the storage capacity of the coolant in the groove smaller, and the recess can be part of the hydrodynamic optimization to reduce the formation of turbulence and eddy currents, thereby reducing the resistance when the coolant flows, more precisely controlling the flow direction of the coolant, ensuring that the coolant flows along the predetermined path, and improving the cooling efficiency.

[0266] Based on the above specific embodiments, the shapes of both sides of the inlet and outlet water dividing member 14 are the same and parallel, and the water passing area of the cavity in the circumferential direction covers 360°. The inlet and outlet water dividing member 14 is made as thin as possible. The shapes of both sides of the inlet and outlet water dividing member 14 are the same and parallel, that is, the recesses on both sides are axially offset, and the recesses on both sides have an overlapping length in the circumferential direction. The water passing area of the cavity in the circumferential direction covers 360°, that is, the coolant flow path covers the entire circumferential area, and the coolant can contact the heat generating component in all directions, thereby providing a uniform cooling effect, avoiding local overheating, and ensuring a uniform temperature distribution of the entire component.

[0267] Based on the above specific embodiments, it further includes a flow rate control device, which is used to control the inlet flow rate of the inlet nozzle 12 according to the relationship that the water temperature at the outlet nozzle 13 is proportional to the inlet flow rate at the inlet nozzle 12. The flow rate control device can dynamically adjust the flow rate at the inlet nozzle 12 according to the change in the water temperature at the outlet nozzle 13 to achieve precise flow rate control, maintain the required temperature conditions, and improve the efficiency and response speed of the system.

[0268] Based on the above specific embodiments, it further includes a water temperature control device, which is used to control the cooling water temperature entering the inlet nozzle 12 according to the relationship that the water temperature at the outlet nozzle 13 is inversely proportional to the cooling water temperature entering the inlet nozzle 12. The water temperature control device can dynamically adjust the cooling water temperature at the inlet nozzle 12 in response to the change in the water temperature at the outlet nozzle 13, thereby maintaining the required temperature conditions and improving the efficiency and accuracy of the system.

[0269] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0270] The above has introduced in detail the range extender assembly and its control and drive method applied to a hybrid lawn mower. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. Therefore, the present invention will not be limited to these embodiments shown in this article, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A range extender assembly for a hybrid lawn mower, characterized in that: The range extender assembly comprises an engine system (1), a generator system (2) and a range extender control unit (3); the engine system (1) comprises an engine assembly and an engine control unit; the generator system (2) comprises a generator assembly and a generator control unit; the rotor of the generator assembly is connected to the crankshaft of the engine assembly; a fan assembly (7) is provided on the air intake side of the engine assembly; the fan assembly (7) is connected to the crankshaft and its air outlet position is aligned with the cylinder head (8) of the engine assembly; the range extender control unit (3) is connected to the engine control unit and the generator control unit; The range extender control unit (3) is used to determine the target output power of the range extender assembly according to the corresponding relationship between the required power and the target output power; and select the target mechanical power of the range extender assembly corresponding to the high efficiency point according to a preset target mechanical power curve corresponding to the target output power of the range extender assembly; The target speed and target torque corresponding to the target mechanical power are determined and sent to the engine control unit and the generator control unit; the engine assembly and the generator assembly are controlled to output power according to the target speed and the target torque.

2. The range extender assembly according to claim 1, characterized in that: The engine assembly is provided with a mounting shaft (5) and an adjustment shaft parallel to the crankshaft. The fan assembly (7) is mounted on the mounting shaft (5). The mounting shaft (5), the crankshaft and the adjustment shaft are all provided with pulleys (6). The pulleys (6) of the three are connected by belts. The adjustment shaft can make a circular motion around the crankshaft. The mounting shaft (5) follows the adjustment shaft so that the air outlet position of the fan assembly (7) is aligned with the cylinder head (8) of the engine assembly.

3. The range extender assembly according to claim 2, characterized in that: Also includes: A temperature sensor mounted on the cylinder head (8) for detecting the temperature of the cylinder head (8); A moving drive device connected to the temperature sensor and used for driving the mounting shaft (5) to move along its axial direction so as to keep the temperature of the cylinder head (8) within a set range.

4. The range extender assembly according to claim 3, characterized in that: The moving drive device comprises an electromagnet (4) disposed at the outer end of the housing of the engine assembly, the electromagnet (4) being coaxial with the mounting shaft (5), and when the electromagnet (4) is energized, the electromagnetic force exerted by the electromagnet (4) on the mounting shaft (5) drives the mounting shaft (5) to move toward an end close to the cylinder head (8); and further comprises a return spring disposed on the mounting shaft (5) for driving the mounting shaft (5) to return to an initial position.

5. A driving method for a range extender assembly applied to a hybrid lawn mower according to any one of claims 1 to 4, characterized in that: Includes steps: Using the formula Calculate the power requirement of the lawn mower, where is the required power, The driving power of the lawn mower. For lawn mower mowing power, The charging and discharging power of the power battery. Other load power for lawn mower; Determining the target output power of the range extender assembly according to the correspondence between the required power and the target output power; According to a preset target mechanical power curve corresponding to the target output power of the range extender assembly, selecting the target mechanical power of the range extender assembly corresponding to the high efficiency point; Determining a target speed and a target torque corresponding to the target mechanical power, and sending the results to the engine control unit and the generator control unit; The engine assembly and the generator assembly are controlled to output power according to the target speed and the target torque.

6. The driving method according to claim 5, characterized in that: According to the corresponding relationship between the required power and the target output power described in the formula, it specifically includes: comparing the required power and the target output power, When the battery SOC is greater than the upper limit threshold, the target output power is determined to be equal to the required power minus the discharge power of the battery; When the battery SOC is between the lower threshold and the upper threshold, determining the target output power=the required power; When the battery SOC is less than the lower limit threshold, the target output power is determined to be equal to the required power + the charging power of the battery.

7. The driving method according to claim 5, characterized in that: Between the preset target mechanical power curve corresponding to the target output power of the range extender assembly and the curve sent to the engine control unit and the generator control unit, it also includes: Select multiple target mechanical powers corresponding to high efficiency points as candidate target mechanical powers; Selecting the optimal target mechanical power from a plurality of candidate target mechanical powers according to the overall performance of the lawn mower; An optimal target speed and an optimal target torque corresponding to the optimal target mechanical power are determined and sent to the engine control unit and the generator control unit.

8. The driving method according to claim 5, characterized in that: After controlling the engine assembly and the generator assembly to output power according to the target speed and the target torque, the method further includes: Detecting an actual output voltage and an actual output current of the generator assembly; Receive the actual output voltage and the actual output current, and use the formula Calculate the actual output power of the range extender assembly, where: is the actual output power of the range extender assembly, is the actual output voltage of the generator assembly, is the actual output current of the generator assembly; The actual output power is compared with the target output power. When the actual output power is greater than the target output power, the actual output power of the range extender assembly is reduced until it is equal to the target output power; when the actual output power is less than the target output power, the actual output power of the range extender assembly is increased until it is equal to the target output power.

9. The driving method according to claim 5, characterized in that: The method for the range extender control unit (3) to control the starting of the engine assembly comprises: Calculating the target starting torque required for the current start based on the current temperature of the engine assembly and the crankshaft position; Sending the starting target torque to the generator control unit to control the generator assembly to output torque with the starting target torque, so that the rotor of the generator assembly drives the crankshaft of the engine assembly to rotate; The actual rotation speed of the generator assembly is monitored and compared with a preset rotation speed, and when the actual rotation speed reaches the preset rotation speed, the engine assembly is controlled to start.

10. The driving method according to claim 9, characterized in that: The starting target torque is estimated based on the starting target time, the starting target speed, the friction loss torque, the pumping loss torque, and the compression loss torque. The specific method includes: According to the formula Calculate the starting target angular velocity, where n is the starting target rotation speed; According to the formula Calculate the starting angular acceleration, where t is the starting target time; According to the formula Calculate the starting torque, where I is the moment of inertia; According to the formula Calculate the starting target torque, where: is the friction loss torque, is the pump loss torque, is the compression loss torque.

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