阅读说明：本技术 发动机用带能量回收功能的电动增压系统 (Electric supercharging system with energy recovery function for engine ) 是由 李卫国 胡前 谢毅 王景智 谢文 张少华 刘嘉璐 于 2020-08-31 设计创作，主要内容包括：本发明提供了一种发动机用带能量回收功能的电动增压系统：发动机的进气管内设置有第一压力传感器；第一压力传感器信号输出端与控制器的输入端电连接；控制器的输出端分别与电动增压器的电动机和压缩空气喷嘴电连接,用于控制两者的工作状态；电动机用于驱动第一压气机的运转；涡轮增压器的涡轮通过发动机的排气能量驱动而第二压气机运转；控制器与EBS控制器电连接,用于接收制动状态信号并判断汽车制动状态；控制器与蓄电池电连接；发电机的输入端与发动机的输出端电连接；发电机的输出端分别与蓄电池的输入端和电动机的电源输入端电连接；蓄电池的输出端与电动机的电源输入端电连接；蓄电池和发电机的连接线路上设置有继电器。(The invention provides an electric supercharging system with an energy recovery function for an engine, which comprises: a first pressure sensor is arranged in an air inlet pipe of the engine; the signal output end of the first pressure sensor is electrically connected with the input end of the controller; the output end of the controller is respectively electrically connected with the motor of the electric supercharger and the compressed air nozzle and is used for controlling the working states of the motor and the compressed air nozzle; the motor is used for driving the first air compressor to operate; the turbine of the turbocharger is driven by the exhaust energy of the engine and the second compressor is operated; the controller is electrically connected with the EBS controller and used for receiving the braking state signal and judging the braking state of the automobile; the controller is electrically connected with the storage battery; the input end of the generator is electrically connected with the output end of the engine; the output end of the generator is respectively and electrically connected with the input end of the storage battery and the power input end of the motor; the output end of the storage battery is electrically connected with the power input end of the motor; and a relay is arranged on a connecting line of the storage battery and the generator.)

1. The utility model provides an engine is with electronic turbocharging system of taking energy recuperation function which characterized in that: the system comprises an electric supercharger, an engine, a turbocharger, an air storage tank, a controller, an EBS controller, a storage battery and a generator; the air inlet is respectively communicated with the air inlet ends of a first air compressor of the electric supercharger and a second air compressor of the turbocharger through pipelines, and the air outlet end of the first air compressor is communicated with the air inlet end of the second air compressor through a pipeline; a one-way valve is arranged on a pipeline of which the air inlet is communicated with the second air compressor; the air outlet end of the air storage tank is communicated with the air inlet end of the first air compressor through a pipeline, and a compressed air nozzle is arranged on the pipeline; the air outlet end of the second air compressor is communicated with an air inlet pipe of the engine, and the air outlet pipe of the engine is communicated with the air inlet end of a turbine of the turbocharger; the air outlet end of the turbocharger is communicated with external air; a first pressure sensor is arranged in an air inlet pipe of the engine; (ii) a The signal output end of the first pressure sensor is electrically connected with the input end of the controller; the output end of the controller is respectively electrically connected with the motor of the electric supercharger and the compressed air nozzle and is used for controlling the working states of the motor and the compressed air nozzle; the motor is used for driving the first air compressor to operate; the turbine of the turbocharger is driven by the exhaust energy of the engine and the second compressor is operated; the controller is electrically connected with the EBS controller and used for receiving the braking state signal and judging the braking state of the automobile; the controller is electrically connected with the storage battery and used for detecting the voltage of the storage battery and judging the residual electric quantity of the storage battery through the battery electric quantity model; the input end of the generator is electrically connected with the output end of the engine; the output end of the generator is respectively and electrically connected with the input end of the storage battery and the power input end of the motor; the output end of the storage battery is electrically connected with the power input end of the motor; a relay is arranged on a connecting line of the storage battery and the generator, and the controller drives the relay to switch the on-off state.

2. The electric supercharging system with the energy recovery function for the engine according to claim 1, characterized by further comprising an air compressor and a clutch, wherein a second pressure sensor is arranged at an air outlet end of the air storage tank, and a signal output end of the second pressure sensor is electrically connected with an input end of the controller; the output end of the engine is connected with an air compressor through a clutch; the output end of the controller is electrically connected with the control signal input end of the clutch; the air outlet end of the air compressor is communicated with the air inlet end of the air storage tank through a pipeline; when the controller judges that the air storage tank is in an inflation-allowable state according to the feedback information of the second pressure sensor, the clutch is controlled to be engaged, so that the air compressor is in a working state and outputs air to the air storage tank.

3. The electric supercharging system with the energy recovery function for the engine according to claim 1, characterized in that: the turbocharger air inlet system is characterized by further comprising an air inlet intercooler, wherein the air outlet end of a second air compressor of the turbocharger is communicated with an air inlet pipe of the engine through the air inlet intercooler, and the air inlet intercooler cools air which passes through the second air compressor.

4. The electric supercharging system with the energy recovery function for the engine according to claim 2, characterized in that: the gas holder includes two, and two gas holders are linked together through the pipeline, and are provided with four return circuit protection valves on this pipeline.

5. The electric supercharging system with energy recovery function for the engine according to claim 1, characterized in that the check valve is in a normally closed position by default; when the electric supercharger does not work, the pressure of the inlet of the one-way valve is larger than the pressure of the outlet, and air is directly led into the second air compressor through the one-way valve; when the electric supercharger works, air is respectively led into the second air compressor through the one-way valve and the first air compressor, and when the pressure difference between the outlet and the inlet of the one-way valve is larger than the cut-off pressure, the one-way valve is fully closed.

6. The electric supercharging system with energy recovery function for an engine according to claim 1, wherein the compressed air nozzle is in a normally closed position by default; the controller drives the compressed air nozzle to open or close according to the vehicle state.

7. The electric supercharging system with the energy recovery function for the engine according to claim 6, characterized in that the first pressure sensor detects the intake pressure of the engine in real time and feeds back pressure information to the controller, and the controller makes a judgment on the current intake demand information of the engine according to the pressure information;

if the controller judges that the engine is operated under the working condition that the air inflow demand of the rapid acceleration is rapidly increased and auxiliary air inflow is needed, the controller controls a motor of the electric supercharger to operate at the required rotating speed according to preset control parameters through the rotating speed of the engine, the opening degree of an accelerator pedal and pressure information, drives a first air compressor to compress air, controls a compressed air nozzle to periodically open and close, and drives an air storage tank to supply air;

if the controller judges that the engine operates under the working condition of low rotating speed and high torque with high air inflow requirement and the air inflow needs to be increased, the controller controls the motor of the electric supercharger to operate and drives the first air compressor to supercharge the intake air;

when the motor of the electric supercharger operates, if the pressure sensor detects that the air inlet pressure of the engine is lower than the lowest threshold value, the controller controls the compressed air nozzle to be opened to drive the air storage tank to supply air.

8. The electric supercharging system with the energy recovery function for the engine according to claim 1, wherein when the controller determines that the vehicle is in a braking state, the engine is in a towing state, and the remaining capacity of the battery is in a charging-allowed state, the controller controls the relay to be closed; the engine makes the generator in generating state to charge the accumulator.

9. The electric supercharging system with the energy recovery function for the engine according to claim 1, wherein the controller drives the battery to supply power to the electric motor when the controller determines that the electric motor of the electric supercharger is in a demand operation state and the remaining capacity of the battery is in a discharge-allowed state.

10. The electric supercharging system with the energy recovery function for the engine according to claim 1, wherein when the controller determines that the electric motor of the electric supercharger is in a required working state and the remaining electric quantity of the storage battery is in a non-discharge-allowed state, the controller controls the relay to be closed, the engine drives the generator to be in a power generation state, and the generator supplies power to the electric motor and charges the storage battery; if the power supply capacity of the generator is insufficient, the storage battery participates in supplying power to the motor.

11. The electric supercharging system with the energy recovery function for the engine according to claim 1, wherein when the controller determines that the remaining electric quantity of the storage battery is in a state requiring charging, the controller controls the relay to be closed, and the engine drives the generator to be in a power generation state to charge the storage battery; and when the controller judges that the residual electric quantity of the storage battery is higher than the charging stop limit value, the controller controls the relay to be switched off.

Technical Field

The invention belongs to the technical field of engines, and particularly relates to an electric supercharging system with an energy recovery function for an engine.

Background

When the engine works, the output torque of the engine is increased by adopting the turbocharging device under the condition of not increasing the displacement of the engine. The automobile is powered by the generator driven by the engine, constant voltage is output to provide electric energy for the vehicle-mounted electric appliance, and when the power of the generator is insufficient, the storage battery participates in providing the electric energy. When the automobile is braked, a mechanical brake system provides braking force, and the kinetic energy of the automobile is converted into heat through the friction plate and dissipated into air. In the general turbocharged engine, the boost pressure is insufficient due to insufficient exhaust gas capacity at low rotating speed, the increase of fuel injection quantity is limited, and the low rotating speed torque performance is poor. The energy provided by fuel combustion during the acceleration of the automobile is converted into the kinetic energy of the automobile, the kinetic energy of the automobile is converted into heat during the braking of the automobile and the heat is dissipated into the air, and the fuel is lost from the energy perspective.

Disclosure of Invention

The invention aims to solve the defects of the background technology, and provides an electric supercharging system with an energy recovery function for an engine.

The technical scheme adopted by the invention is as follows: the utility model provides an engine is with electronic turbocharging system of taking energy recuperation function which characterized in that: the system comprises an electric supercharger, an engine, a turbocharger, an air storage tank, a controller, an EBS controller, a storage battery and a generator; the air inlet is respectively communicated with the air inlet ends of a first air compressor of the electric supercharger and a second air compressor of the turbocharger through pipelines, and the air outlet end of the first air compressor is communicated with the air inlet end of the second air compressor through a pipeline; a one-way valve is arranged on a pipeline of which the air inlet is communicated with the second air compressor; the air outlet end of the air storage tank is communicated with the air inlet end of the first air compressor through a pipeline, and a compressed air nozzle is arranged on the pipeline; the air outlet end of the second air compressor is communicated with an air inlet pipe of the engine, and the air outlet pipe of the engine is communicated with the air inlet end of a turbine of the turbocharger; the air outlet end of the turbocharger is communicated with external air; a first pressure sensor is arranged in an air inlet pipe of the engine; (ii) a The signal output end of the first pressure sensor is electrically connected with the input end of the controller; the output end of the controller is respectively electrically connected with the motor of the electric supercharger and the compressed air nozzle and is used for controlling the working states of the motor and the compressed air nozzle; the motor is used for driving the first air compressor to operate; the turbine of the turbocharger is driven by the exhaust energy of the engine and the second compressor is operated; the controller is electrically connected with the EBS controller and used for receiving the braking state signal and judging the braking state of the automobile; the controller is electrically connected with the storage battery and used for detecting the voltage of the storage battery and judging the residual electric quantity of the storage battery through the battery electric quantity model; the input end of the generator is electrically connected with the output end of the engine; the output end of the generator is respectively and electrically connected with the input end of the storage battery and the power input end of the motor; the output end of the storage battery is electrically connected with the power input end of the motor; a relay is arranged on a connecting line of the storage battery and the generator, and the controller drives the relay to switch the on-off state.

In the technical scheme, the air compressor and the clutch are further included, a second pressure sensor is arranged at the air outlet end of the air storage tank, and the signal output end of the second pressure sensor is electrically connected with the input end of the controller; the output end of the engine is connected with an air compressor through a clutch; the output end of the controller is electrically connected with the control signal input end of the clutch; the air outlet end of the air compressor is communicated with the air inlet end of the air storage tank through a pipeline; when the controller judges that the air storage tank is in an inflation-allowable state according to the feedback information of the second pressure sensor, the clutch is controlled to be engaged, so that the air compressor is in a working state and outputs air to the air storage tank.

In the technical scheme, the turbocharger air inlet cooling device further comprises an air inlet intercooler, the air outlet end of the second air compressor of the turbocharger is communicated with an air inlet pipe of the engine through the air inlet intercooler, and the air inlet intercooler cools air which passes through the second air compressor.

In the technical scheme, the two gas storage tanks are communicated through a pipeline, and four-loop protection valves are arranged on the pipeline.

In the technical scheme, the one-way valve is in a normally closed position by default; when the electric supercharger does not work, the pressure of the inlet of the one-way valve is larger than the pressure of the outlet, and air is directly led into the second air compressor through the one-way valve; when the electric supercharger works, air is respectively led into the second air compressor through the one-way valve and the first air compressor, and when the pressure difference between the outlet and the inlet of the one-way valve is larger than the cut-off pressure, the one-way valve is fully closed.

In the technical scheme, the compressed air nozzle is in a normally closed position by default; the controller drives the compressed air nozzle to open or close according to the vehicle state.

In the technical scheme, the first pressure sensor detects the air inlet pressure of the engine in real time and feeds pressure information back to the controller, and the controller judges the current air inlet demand information of the engine according to the pressure information;

if the controller judges that the engine is operated under the working condition that the air inflow demand of the rapid acceleration is rapidly increased and auxiliary air inflow is needed, the controller controls a motor of the electric supercharger to operate at the required rotating speed according to preset control parameters through the rotating speed of the engine, the opening degree of an accelerator pedal and pressure information, drives a first air compressor to compress air, controls a compressed air nozzle to periodically open and close, and drives an air storage tank to supply air;

if the controller judges that the engine operates under the working condition of low rotating speed and high torque with high air inflow requirement and the air inflow needs to be increased, the controller controls the motor of the electric supercharger to operate and drives the first air compressor to supercharge the intake air;

when the motor of the electric supercharger operates, if the pressure sensor detects that the air inlet pressure of the engine is lower than the lowest threshold value, the controller controls the compressed air nozzle to be opened to drive the air storage tank to supply air.

In the technical scheme, when the controller judges that the automobile is in a braking state, the engine is in a dragging state and the residual electric quantity of the storage battery is in a charging allowed state, the controller controls the relay to be closed; the engine makes the generator in generating state to charge the accumulator.

In the technical scheme, when the controller judges that the motor of the electric supercharger is in a required working state and the residual electric quantity of the storage battery is in a discharge-allowed state, the controller drives the storage battery to supply power to the motor.

In the technical scheme, when the controller judges that the motor of the electric supercharger is in a required working state and the residual electric quantity of the storage battery is in a state of not allowing discharge, the controller controls the relay to be closed, the engine drives the generator to be in a power generation state, and the generator supplies power to the motor and charges the storage battery; if the power supply capacity of the generator is insufficient, the storage battery participates in supplying power to the motor.

In the technical scheme, when the controller judges that the residual electric quantity of the storage battery is in a state needing charging, the controller controls the relay to be closed, and the engine drives the generator to be in a power generation state to charge the storage battery; and when the controller judges that the residual electric quantity of the storage battery is higher than the charging stop limit value, the controller controls the relay to be switched off.

The invention realizes the recovery, storage and utilization of braking energy and reduces the oil consumption by utilizing the cooperative work of the generator, the storage battery, the electric supercharger and the EBS system. The invention solves the problem of pneumatic lag of the turbocharger by utilizing the quick response capability of electric pressurization and air supply of the whole vehicle air storage system, and improves the dynamic response performance of the engine. When the automobile is braked, the EBS braking state signal is judged by the controller, and the generator is controlled to generate electricity by utilizing the engine dragging-backward working condition, so that the proportion of the electricity generated by the engine actively doing work is reduced, and the oil consumption is reduced; the controller is used for judging the pressure of the automobile air storage tank, and the clutch type air compressor is controlled to compress air by utilizing the working condition of the engine in a dragging mode, so that the proportion of compressing air by the engine to actively work is reduced, and the oil consumption is reduced. When the controller controls the electric supercharger to work, the SOC of the storage battery is judged, the generator is controlled to generate power, and the generator is used for directly supplying power to the electric supercharger, so that the charge and discharge loss of the part of electric quantity is avoided.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a flow chart of an energy recovery function control method of the present invention;

FIG. 3 is a flow chart of a method of controlling the electric boosting system according to the present invention;

FIG. 4 is a flow chart of a battery charging control method of the present invention;

the system comprises an engine 1, a check valve 2, a first air compressor 3, a motor 4, an air storage tank 5, a compressed air nozzle 6, a first pressure sensor 7, a turbine 8, a second air compressor 9, a storage battery 10, a controller 11, an EBS controller 12, a relay 13, a voltage regulator 14, a generator 15, a clutch 16 and an air compressor 17.

Detailed Description

The invention will be further described in detail with reference to the following drawings and specific examples, which are not intended to limit the invention, but are for clear understanding.

As shown in fig. 1, the present invention provides an electric supercharging system with an energy recovery function for an engine, characterized in that: the system comprises an electric supercharger, an engine 1, a turbocharger, an air storage tank 5, a controller 11, an EBS controller 12, a storage battery 10 and a generator 15; the air inlet is respectively communicated with the air inlet ends of a first air compressor 3 of the electric supercharger and a second air compressor 9 of the turbocharger through pipelines, and the air outlet end of the first air compressor 3 is communicated with the air inlet end of the second air compressor 9 through a pipeline; a one-way valve 2 is arranged on a pipeline of which the air inlet is communicated with the second air compressor 9; the air outlet end of the air storage tank is communicated with the air inlet end of the first air compressor 3 through a pipeline, and a compressed air nozzle 6 is arranged on the pipeline; the air outlet end of the second air compressor 9 is communicated with the air inlet pipe of the engine 1, and the air outlet pipe of the engine 1 is communicated with the air inlet end of the turbine 10 of the turbocharger; the air outlet end of the turbocharger is communicated with external air; a first pressure sensor 7 is arranged in an air inlet pipe of the engine 1; the signal output end of the first pressure sensor 7 is electrically connected with the input end of the controller 11; the output end of the controller 11 is respectively electrically connected with the motor 4 and the compressed air nozzle 6 of the electric supercharger and is used for controlling the working states of the motor 4 and the compressed air nozzle; the motor 4 is used for driving the first compressor 3 to operate; the turbine of the turbocharger is driven by the exhaust energy of the engine and the second compressor 9 is operated; the controller 11 is electrically connected with the EBS controller 12 and is used for receiving the braking state signal and judging the braking state of the automobile; the controller 11 is electrically connected with the storage battery 10 and is used for detecting the voltage of the storage battery 10 and judging the residual electric quantity of the storage battery through a battery electric quantity model; the input end of the generator 15 is electrically connected with the output end of the engine; the output end of the generator 15 is respectively and electrically connected with the input end of the storage battery 10 and the power supply input end of the motor 4; the output end of the storage battery 10 is electrically connected with the power input end of the motor 4; a relay 13 is provided on a connection line between the battery 10 and the generator 15, and the controller 11 drives the relay 3 to switch the on/off state. The generator 15 and the air compressor 17 are driven by the engine 1. The controller 11 controls the operating state of the voltage regulator 14 through the relay 13, thereby controlling the power generation state of the generator 15.

In the technical scheme, the air storage tank comprises an air compressor 17 and a clutch 16, wherein a second pressure sensor 18 is arranged at the air outlet end of the air storage tank 5, and the signal output end of the second pressure sensor 18 is electrically connected with the input end of the controller 11; the output end of the engine 1 is connected with an air compressor 17 through a clutch; the output end of the controller 11 is electrically connected with the control signal input end of the clutch 16; the air outlet end of the air compressor 17 is communicated with the air inlet end of the air storage tank 5 through a pipeline; when the controller 11 judges that the air storage tank is in the inflation permitting state according to the feedback information of the second pressure sensor 18, the clutch 16 is controlled to be engaged, so that the air compressor 17 is in the working state and the air is output to the air storage tank 5.

Among the above-mentioned technical scheme, still include the intercooler that admits air, turbocharger's the end of giving vent to anger is linked together through the intake pipe of the intercooler that admits air and engine 1, and the intercooler that admits air through the second compressor cools off, reduces the calorific capacity of engine.

The opening and closing of the compressed air nozzle 6 through the controller are controlled, so that the compressed air in the air storage tank 5 is controlled to enter the first compressor 3 of the electric supercharger. The controller drives the first compressor 3 to rotate by driving the working state of the motor 4, and the intake air is pressurized. The turbocharger drives the turbine to rotate by the exhaust energy of the engine 1, thereby driving the second compressor 9 to supercharge the intake air. The intake intercooler 8 cools the intake air passing through the compressor 9.

When the electric supercharger does not work, the inlet pressure of the check valve 2 is larger than the outlet pressure, and the intake air flowing through the second compressor 9 is directly introduced through the check valve 2. When the electric supercharger works, because the first air compressor 3 supercharges the inlet air, the outlet pressure of the one-way valve 2 is gradually increased, and the inlet air passing through the second air compressor 9 is respectively led in through the one-way valve 2 and the first air compressor 3. When the pressure difference between the outlet and the inlet of the check valve 2 is larger than the cut-off pressure, the check valve 2 is fully closed.

Based on the system structure, the invention provides a control method of a hybrid supercharging system, which comprises the following steps:

1. the compressed air nozzle 6 is in a normally closed position by default and the check valve 2 is in a normally closed position by default.

2. The first pressure sensor 7 detects the air inlet pressure of the engine 1 in real time and feeds pressure information back to the controller, and the controller 11 judges the current air inlet demand information of the engine.

3. If the controller judges that the engine is operated under the working condition that the air inflow demand is rapidly increased such as rapid acceleration and the like and auxiliary air inflow is needed, the controller 11 calculates the required rotating speed of the motor according to preset control parameters through the information of the rotating speed of the engine, the opening degree of an accelerator pedal, the pressure after air inflow pressurization and intercooling and the like, controls the motor 4 of the electric supercharger to operate at the required rotating speed, drives the first air compressor 3 to compress air, and sends the compressed air to the second air compressor 9 by the first air compressor; the controller controls the compressed air nozzle 6 to be opened and closed periodically, the air storage system supplies air to the first air compressor 3 according to the required air quantity, and the air source of the first air compressor 3 comprises an external environment and an air storage tank;

4. if the engine is judged to be operated under the working condition of low rotating speed, large torque and the like with large air inflow requirement and the air inflow needs to be increased, the controller 11 controls the motor 4 to operate and drives the first air compressor 3 to pressurize the inlet air;

5. when the motor 4 is operated, if the pressure sensor 7 detects that the intake pressure of the engine 1 is lower than the minimum threshold value, the compressed air nozzle 6 is controlled to be opened, the air storage system supplies air to the first air compressor 3 according to the required air quantity, and the air source of the first air compressor 3 comprises an external environment and an air storage tank.

6. If the conditions are not the same, the electric supercharger does not operate, the gas storage system does not supply gas, and the turbocharger operates normally.

As shown in fig. 2, based on the above system structure, an embodiment of the present invention provides a method for controlling an energy recovery function of the system.

The method comprises the following steps:

1. the controller 11 receives the braking state signal from the EBS controller 12 and determines the braking state of the vehicle.

2. The controller 11 determines the SOC of the battery 10 by detecting the voltage of the battery 10 and by using a battery power model.

3. The pressure of the compressed air in the air tank of the vehicle is detected in real time by the pressure sensor 18.

4. When the automobile is in a braking state, the engine 1 is in a dragging state, and the SOC of the storage battery 10 is judged to be in a charging allowable state, the controller 11 controls the relay 13 to be closed, so that the generator 15 is in a power generation state to charge the storage battery 10; when the air storage tank 5 is judged to be in the state of allowing inflation, the clutch 16 is controlled to be engaged, and the air compressor 17 is enabled to be in the working state. At this time, the generator 15 and the air compressor 17 are driven by the braking torque, thereby realizing the conversion and recovery of the braking energy.

As shown in fig. 3, based on the above system structure, the embodiment of the invention provides a control method for an electric supercharging system.

The method comprises the following steps:

1. the air pressure in front of the air inlet of the compressor 3 is detected in real time through the pressure sensor 7, and the current air inlet demand information of the engine is judged by the controller 11.

2. The controller 11 determines the SOC of the battery 10 by detecting the voltage of the battery 10 and by using a battery power model.

3. When the electric supercharger is in the required operation state and the SOC of the battery 10 is in the discharge-allowed state, the controller 11 controls the electric motor 4 of the electric supercharger to operate at the required rotation speed, compressing the intake air. At this time, the motor 4 is supplied with power from the battery 10.

4. When the electric supercharger is in a required operation state and the SOC of the battery 10 is in a non-discharge-allowed state, the controller 11 controls the relay 13 to be closed, so that the generator 15 is in a power generation state, and controls the motor of the electric supercharger to operate at a required rotation speed to compress intake air. At this time, the electric motor 4 is supplied with electric power from the generator 15, and if the electric power supply capability of the generator 15 is insufficient, the battery 10 participates in the electric power supply.

As shown in fig. 4, based on the above system structure, an embodiment of the present invention provides a method for controlling charging of a storage battery.

The method comprises the following steps:

1. the controller 11 determines the SOC of the battery 10 by detecting the voltage of the battery 10 and by using a battery power model.

2. When the SOC of the storage battery 10 is in a charging-required state, the controller 11 controls the relay 13 to be closed, so that the generator 15 is in a power generation state; when the SOC of the battery 10 is higher than the stop charge limit value, the controller 11 controls the relay 13 to be turned off to place the generator 15 in a non-power generation state.

Those not described in detail in this specification are within the skill of the art.