阅读说明：本技术 一种船用发动机推进系统及其控制方法 (Marine engine propulsion system and control method thereof ) 是由 张荣沛 张小玉 于 2020-11-16 设计创作，主要内容包括：本发明实施例公开了一种船用发动机推进系统及其控制方法。该推进系统包括轴带电机、储能模块和控制模块,发动机与轴带电机连接,轴带电机与储能模块连接,控制模块与轴带电机和发动机连接,该方法包括：根据当前时刻系统需求推进总功率和上一时刻发动机的输出功率确定系统需求的发动机功率变化斜率；当系统需求的发动机功率变化斜率满足预设条件时,通过控制轴带电机控制储能模块充电或放电。通过设置当系统需求的发动机功率变化斜率满足预设条件时,通过控制轴带电机控制储能模块充电或放电,以实现在推进系统负荷变化较大时减缓发动机的功率变化幅度,减少爆震,降低颗粒物排放,同时提高能源的利用率的效果。(The embodiment of the invention discloses a marine engine propulsion system and a control method thereof. The propulsion system comprises a shaft motor, an energy storage module and a control module, wherein the engine is connected with the shaft motor, the shaft motor is connected with the energy storage module, the control module is connected with the shaft motor and the engine, and the method comprises the following steps: determining the power change slope of the engine required by the system according to the total propulsion power required by the system at the current moment and the output power of the engine at the last moment; when the change slope of the engine power required by the system meets a preset condition, the energy storage module is controlled to charge or discharge through the control shaft motor. When the change slope of the engine power required by the system meets the preset condition, the energy storage module is controlled to charge or discharge through the control shaft and the motor, so that the power change amplitude of the engine is reduced when the load change of the propulsion system is large, knocking is reduced, particulate matter emission is reduced, and meanwhile, the utilization rate of energy is improved.)

1. A method of controlling a marine engine propulsion system, the propulsion system including an axle motor, an energy storage module, and a control module, the engine being coupled to the axle motor, the axle motor being coupled to the energy storage module, the control module being coupled to the axle motor and the engine, the method comprising:

determining the change slope of the engine power required by the system according to the total propulsion power required by the system at the current moment and the output power of the engine at the last moment;

and when the change slope of the engine power required by the system meets a preset condition, controlling the shaft motor to control the energy storage module to charge or discharge.

2. The method of controlling a marine engine propulsion system according to claim 1, wherein said determining an engine power change slope of a system demand based on a total power demanded by a system at a present time and an output power of said engine at a previous time comprises:

and calculating the power change slope of the engine required by the system according to the ratio of the difference value between the total propulsion power required by the system at the current moment and the output power of the engine at the last moment to a preset time length.

3. The control method of a marine engine propulsion system according to claim 2, characterised in that the preset period of time is 1 second.

4. The control method of a marine engine propulsion system according to claim 1, wherein the controlling the shaft motor to control the energy storage module to be charged or discharged when the slope of the change in engine power required by the system satisfies a preset condition includes:

when the change slope of the engine power required by the system is greater than the preset maximum descending power change slope of the engine, controlling the shaft motor to control the energy storage module to discharge;

and when the change slope of the engine power required by the system is smaller than the preset maximum rising power change slope of the engine, controlling the shaft motor to control the energy storage module to charge.

5. The control method of a marine engine propulsion system according to claim 4, wherein said controlling the shaft motor to control the energy storage module to discharge when the slope of the change in engine power demanded by the system is greater than a preset maximum decreasing power change slope of the engine comprises:

determining the output power of the engine at the current moment according to the preset maximum descending power change slope of the engine, the preset duration and the output power of the engine at the previous moment;

and determining the discharge electric quantity of the energy storage module according to the output power of the engine at the current moment and the total propulsion power required by the system at the current moment.

6. The control method of a marine engine propulsion system according to claim 5, wherein the determining the output power of the engine at the present time based on the preset maximum power-down change slope of the engine, the preset time period, and the output power of the engine at the previous time comprises:

and calculating the output power of the engine at the current moment according to the product of the preset maximum descending power change slope of the engine and the preset duration and the sum of the output power of the engine at the previous moment.

7. The control method of a marine engine propulsion system according to claim 4, wherein the controlling the shaft motor to control the energy storage module to be charged when the slope of the change in engine power demanded by the system is less than a preset maximum rising power change slope of the engine comprises:

determining the output power of the engine at the current moment according to the preset maximum ascending power change slope of the engine, the preset duration and the output power of the engine at the previous moment;

and determining the charging electric quantity of the energy storage module according to the output power of the engine at the current moment and the total propulsion power required by the system at the current moment.

8. The control method of a marine engine propulsion system according to claim 7, wherein the determining the output power of the engine at the present time based on a preset maximum rising power change slope of the engine, a preset time period, and the output power of the engine at the previous time comprises:

and calculating the output power of the engine at the current moment according to the product of the preset maximum ascending power change slope of the engine and the preset duration and the sum of the output power of the engine at the previous moment.

9. The method of controlling a marine engine propulsion system according to claim 1, further comprising, prior to said determining a slope of change in engine power demanded from a total power demanded by the system at a present time and an output power of said engine at a previous time:

and acquiring the total propulsion power required by the system at the current moment and the output power of the engine at the last moment.

10. A marine engine propulsion system, comprising: the shaft motor, the energy storage module and the control module are arranged; the engine is connected with the shaft motor, the shaft motor is connected with the energy storage module, and the control module is connected with the shaft motor and the engine;

the control module is used for determining the change slope of the engine power required by the system according to the total propulsion power required by the system at the current moment and the output power of the engine at the last moment; and when the change slope of the engine power required by the system meets a preset condition, controlling the shaft motor to control the energy storage module to charge or discharge.

Technical Field

The embodiment of the invention relates to a marine engine control technology, in particular to a marine engine propulsion system and a control method thereof.

Background

The marine two-stroke low-pressure dual-fuel engine has the advantages of low natural gas inlet pressure, simple gas supply system structure, less nitrogen oxide emission, low investment cost and the like, and is widely applied to the market of low-speed machines of ships.

However, when the low pressure dual fuel engine is subjected to frequent changes in propulsion load, knocking is likely to occur, which may result in higher particulate emissions. Especially, when the ship accelerates and decelerates frequently and the slope of the change of the propelling power of the engine is steeper, the detonation is easier to occur, so that the power consumption of the propelling system is large and the dynamic response performance is poor.

Disclosure of Invention

When the power change slope of the engine required by the system meets a preset condition, the energy storage module is controlled to charge or discharge by controlling the shaft motor, so that the power change amplitude of the engine is reduced when the load change of the propulsion system is large, the detonation is reduced, the particulate matter emission is reduced, and the utilization rate of energy is improved.

In a first aspect, an embodiment of the present invention provides a control method for a marine engine propulsion system, where the propulsion system includes an axle motor, an energy storage module, and a control module, the engine is connected to the axle motor, the axle motor is connected to the energy storage module, and the control module is connected to the axle motor and the engine, and the method includes:

determining the change slope of the engine power required by the system according to the total propulsion power required by the system at the current moment and the output power of the engine at the last moment;

and when the change slope of the engine power required by the system meets a preset condition, controlling the shaft motor to control the energy storage module to charge or discharge.

Optionally, the determining an engine power change slope of the system demand according to the total power demanded by the system at the current moment and the output power of the engine at the last moment comprises:

and calculating the power change slope of the engine required by the system according to the ratio of the difference value between the total propulsion power required by the system at the current moment and the output power of the engine at the last moment to a preset time length.

Optionally, the preset time period is 1 second.

Optionally, when the slope of the change in power of the engine required by the system meets a preset condition, controlling the shaft-driven motor to control the energy storage module to charge or discharge includes:

when the change slope of the engine power required by the system is greater than the preset maximum descending power change slope of the engine, controlling the shaft motor to control the energy storage module to discharge;

and when the change slope of the engine power required by the system is smaller than the preset maximum rising power change slope of the engine, controlling the shaft motor to control the energy storage module to charge.

Optionally, when the change slope of the engine power required by the system is greater than a preset maximum reduction power change slope of the engine, controlling the shaft motor to control the energy storage module to discharge comprises:

determining the output power of the engine at the current moment according to the preset maximum descending power change slope of the engine, the preset duration and the output power of the engine at the previous moment;

and determining the discharge electric quantity of the energy storage module according to the output power of the engine at the current moment and the total propulsion power required by the system at the current moment.

Optionally, the determining the output power of the engine at the current moment according to the preset maximum power reduction change slope of the engine, the preset duration and the output power of the engine at the last moment comprises:

and calculating the output power of the engine at the current moment according to the product of the preset maximum descending power change slope of the engine and the preset duration and the sum of the output power of the engine at the previous moment.

Optionally, when the change slope of the engine power required by the system is smaller than a preset maximum rising power change slope of the engine, controlling the shaft motor to control the energy storage module to charge comprises:

determining the output power of the engine at the current moment according to the preset maximum ascending power change slope of the engine, the preset duration and the output power of the engine at the previous moment;

and determining the charging electric quantity of the energy storage module according to the output power of the engine at the current moment and the total propulsion power required by the system at the current moment.

Optionally, the determining the output power of the engine at the current moment according to the preset maximum ascending power change slope of the engine, the preset time length and the output power of the engine at the last moment comprises:

and calculating the output power of the engine at the current moment according to the product of the preset maximum ascending power change slope of the engine and the preset duration and the sum of the output power of the engine at the previous moment.

Optionally, before determining the slope of the change in engine power demanded by the system according to the total power demanded by the system at the current time and the output power of the engine at the last time, the method further comprises:

and acquiring the total propulsion power required by the system at the current moment and the output power of the engine at the last moment.

In a second aspect, an embodiment of the present invention further provides a marine engine propulsion system, including: the shaft motor, the energy storage module and the control module are arranged; the engine is connected with the shaft motor, the shaft motor is connected with the energy storage module, and the control module is connected with the shaft motor and the engine;

the control module is used for determining the change slope of the engine power required by the system according to the total propulsion power required by the system at the current moment and the output power of the engine at the last moment; and when the change slope of the engine power required by the system meets a preset condition, controlling the shaft motor to control the energy storage module to charge or discharge.

The invention provides a control method of a propulsion system of a marine engine, wherein the propulsion system comprises a shaft motor, an energy storage module and a control module, the engine is connected with the shaft motor, the shaft motor is connected with the energy storage module, and the control module is connected with the shaft motor and the engine, and the method comprises the following steps: determining the power change slope of the engine required by the system according to the total propulsion power required by the system at the current moment and the output power of the engine at the last moment; when the change slope of the engine power required by the system meets a preset condition, the energy storage module is controlled to charge or discharge through the control shaft motor. The method solves the problems that the existing marine engine is easy to knock, has large system power consumption and the like when the propulsive load changes frequently. When the change slope of the engine power required by the system meets the preset condition, the energy storage module is controlled to charge or discharge through the control shaft and the motor, so that the power change amplitude of the engine is reduced when the load change of the propulsion system is large, knocking is reduced, particulate matter emission is reduced, and meanwhile, the utilization rate of energy is improved.

Drawings

FIG. 1 is a schematic illustration of a marine engine propulsion system according to a first embodiment of the present invention;

FIG. 2 is a flow chart of a method of controlling a marine engine propulsion system according to a first embodiment of the present invention;

fig. 3 is a flowchart of a control method of a marine engine propulsion system according to a second embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Example one

Fig. 1 is a block diagram showing a configuration of a marine engine propulsion system according to a first embodiment of the present invention, and fig. 2 is a flowchart showing a control method of the marine engine propulsion system according to the first embodiment of the present invention. Referring to fig. 1, the propulsion system includes a shaft motor 20, an energy storage module 30, and a control module 40, the engine 10 is coupled to the shaft motor 20, the shaft motor 20 is coupled to the energy storage module 30, and the control module 40 is coupled to the shaft motor 20 and the engine 10.

The output of the shaft motor 20 is connected to a load, for example to a propeller 1 with a fixed pitch. The shaft motor 20 is used for outputting power to drive the propeller 1 to rotate.

The engine 10 may be a two-stroke low-pressure dual-fuel engine, which has advantages of low natural gas intake pressure, simple gas supply system structure, low nitrogen oxide emission, low cost, and the like. The energy storage module 30 may be an energy storage battery, such as a rechargeable lithium battery. The energy storage module 30 is bidirectionally connected with the shaft motor 20, and can realize charging and discharging functions. The control module 40 may be a single chip microcomputer, a PLC controller, etc.

The embodiment is applicable to the implementation process of the control method of the marine engine propulsion system, which can be executed by the marine engine propulsion system provided by the embodiment of the invention, and referring to fig. 2, the control method specifically includes the following steps:

and step 110, determining the change slope of the engine power required by the system according to the total propulsion power required by the system at the current moment and the output power of the engine at the last moment.

The total propulsion power required by the system at the current moment refers to the total power required by the load connected with the output end of the shaft-driven motor, for example, the total power required by the rotation of the propeller 1. The output power of the engine at the last moment can represent historical parameters of the output power of the engine. Typically, when the system propulsion load varies more (or the total system demanded propulsion power varies more), the rate at which the engine power demanded by the system varies is also greater. Wherein the rate of change of the engine power demanded by the system may be represented by a slope of change of the engine power demanded by the system. Therefore, the change slope of the engine power required by the system at the current moment can be judged according to the total propelling power required by the system at the current moment and the output power of the engine at the last moment.

And step 120, when the power change slope of the engine required by the system meets a preset condition, controlling the energy storage module to charge or discharge through the control shaft motor.

For example, when the change slope of the power of the engine required by the system is larger than the change slope of the power of the output preset by the engine, namely the change rate of the power which can be actually provided by the engine is smaller than the change rate of the power required by the system, the control module controls the energy storage module to discharge through controlling the shaft motor, and the energy storage module discharges and outputs electric energy to compensate the difference value of the change rate of the power which can be actually provided by the engine and the change rate of the power which is smaller than the change rate of the system required by the engine, so as to meet the change rate of. When the power change slope of the engine required by the system is smaller than the power change slope of the output preset by the engine, namely the power change rate actually provided by the engine is larger than the power change rate required by the system, the control module controls the energy storage module to charge through controlling the shaft-driven motor, so that the redundant power actually output by the engine is stored by charging the energy storage module. When the power change slope of the engine required by the system is equal to the power change slope of the output preset by the engine, namely the power change rate which can be actually provided by the engine just meets the power change rate required by the system, the energy storage module is not charged or discharged. Therefore, when the load change of the propulsion system is large, and the power change rate of the system requirement is large, the power change amplitude of the engine can be reduced, the knocking is reduced, the particulate matter emission is reduced, and meanwhile, the utilization rate of energy is improved according to the condition met by the power change slope of the engine required by the system and the charging or discharging of the energy storage module is controlled by controlling the shaft motor.

In the technical scheme of the embodiment, the working principle of the control method of the marine engine propulsion system is as follows: first, the engine power change slope of the system demand is determined based on the total propulsion power demanded by the system at the present time and the output power of the engine at the previous time. And then, when the change slope of the engine power required by the system meets a preset condition, controlling the energy storage module to charge or discharge through the control shaft motor. Therefore, when the load change of the propulsion system is large, and the power change rate of the system requirement is large, the power change amplitude of the engine can be reduced, the knocking is reduced, the particulate matter emission is reduced, and meanwhile, the utilization rate of energy is improved according to the condition met by the power change slope of the engine required by the system and the charging or discharging of the energy storage module is controlled by controlling the shaft motor.

According to the technical scheme of the embodiment, the control method for the propulsion system of the marine engine is used, the propulsion system comprises a shaft motor, an energy storage module and a control module, the engine is connected with the shaft motor, the shaft motor is connected with the energy storage module, and the control module is connected with the shaft motor and the engine, and the method comprises the following steps: determining the power change slope of the engine required by the system according to the total propulsion power required by the system at the current moment and the output power of the engine at the last moment; when the change slope of the engine power required by the system meets a preset condition, the energy storage module is controlled to charge or discharge through the control shaft motor. The method solves the problems that the existing marine engine is easy to knock, has large system power consumption and the like when the propulsive load changes frequently. When the change slope of the engine power required by the system meets the preset condition, the energy storage module is controlled to charge or discharge through the control shaft and the motor, so that the power change amplitude of the engine is reduced when the load change of the propulsion system is large, knocking is reduced, particulate matter emission is reduced, and meanwhile, the utilization rate of energy is improved.

Example two

Fig. 3 is a flowchart of a control method of a marine engine propulsion system according to a second embodiment of the present invention. On the basis of the above embodiment, optionally, before determining the engine power change slope of the system demand according to the total power demanded by the system at the current time and the output power of the engine at the last time, the method further includes:

and acquiring the total propulsion power required by the system at the current moment and the output power of the engine at the last moment.

The total propulsion power required by the system at the current moment and the output power of the engine at the previous moment can be monitored in real time through the power detection module. The power detection module can comprise a current detection unit and a voltage detection unit, the current detection unit can detect the current value of the current moment system and the current value of the engine at the previous moment in real time, the voltage detection unit can detect the voltage value of the current moment system and the voltage value of the engine at the previous moment in real time, the total propulsion power required by the current moment system can be obtained according to the detected current value and the detected voltage value of the current moment system, and the output power of the engine at the previous moment can be obtained according to the detected current value of the engine at the previous moment and the detected voltage value of the engine at the previous moment.

Optionally, determining an engine power change slope of the system demand based on the total power demanded by the system at the present time and the output power of the engine at the previous time, comprises:

and calculating the power change slope of the engine required by the system according to the ratio of the difference value between the total propulsion power required by the system at the current moment and the output power of the engine at the previous moment and the preset time length.

Referring to fig. 3, let total propulsion power demanded by system at present time be P_P(t), the output power of the engine at the previous moment is P_m(t-1), the slope of change of the engine power required by the system is R, and the slope of change of the engine power required by the system is R:

R＝(P_P(t)-P_m(t-1))/T_s

wherein, T_sIs a preset duration. The preset time period may be set to 1 second, 0.5 second, 1.5 second, etc. The specific value may be set according to actual conditions, and is not specifically limited in this embodiment.

Optionally, when the slope of the change of the engine power required by the system meets a preset condition, controlling the shaft-driven motor to control the energy storage module to charge or discharge comprises:

when the change slope of the power of the engine required by the system is greater than the preset maximum reduction power change slope of the engine, controlling the shaft-driven motor to control the energy storage module to discharge;

and when the change slope of the power of the engine required by the system is smaller than the preset maximum rising power change slope of the engine, controlling the shaft-driven motor to control the energy storage module to charge.

The preset maximum ascending power change slope and the preset maximum descending power change slope of the engine can be set through the control module according to the combustion performance of the engine and the maximum ascending power change slope and the maximum descending power change slope of the engine, which can be reached when the engine normally runs, and specific numerical values can be set according to actual conditions without specific limitation. Alternatively, the preset maximum downward power change slope of the engine may be set to be greater than the preset maximum upward power change slope of the engine.

Specifically, when the change slope of the engine power required by the system is greater than the change slope of the preset maximum descending power of the engine, namely the change rate of the power actually provided by the engine is smaller than the change rate of the power required by the system, the control module controls the energy storage module to discharge through the control shaft motor, and the energy storage module discharges and outputs electric energy to compensate the difference value that the change rate of the power actually provided by the engine is smaller than the change rate of the power required by the system, so that the change slope of the engine power required by the system is met. When the change slope of the power of the engine required by the system is smaller than the preset maximum rising power change slope of the engine, namely the change rate of the power which can be actually provided by the engine is larger than the change rate of the power required by the system, the control module controls the energy storage module to charge through controlling the shaft-driven motor, so that the redundant power which can be actually output by the engine is stored by charging the energy storage module. When the change slope of the engine power required by the system is greater than the preset maximum ascending power change slope of the engine and less than the preset maximum descending power change slope of the engine, namely the power change rate which can be actually provided by the engine just meets the power change rate required by the system, the control module controls the shaft-driven motor to stop working, and at the moment, the energy storage module is not discharged or charged. Therefore, when the load change of the propulsion system is large, and the power change rate of the system requirement is large, the power change amplitude of the engine can be reduced, the knocking is reduced, the particulate matter emission is reduced, and meanwhile, the utilization rate of energy is improved according to the condition met by the power change slope of the engine required by the system and the charging or discharging of the energy storage module is controlled by controlling the shaft motor.

The change slope of the preset maximum descending power of the engine is set as R_dThe maximum rising power change gradient of the engine is preset to be R_uThe power of the energy storage module is P_e(t) current time pointOutput power of motive machine is P_m(t)。

Optionally, when the change slope of the engine power required by the system is greater than the preset maximum reduction power change slope of the engine, controlling the shaft-driven motor to control the energy storage module to discharge comprises:

determining the output power of the engine at the current moment according to the preset maximum descending power change slope of the engine, the preset duration and the output power of the engine at the previous moment;

and determining the discharge electric quantity of the energy storage module according to the output power of the engine at the current moment and the total propulsion power required by the system at the current moment.

Optionally, determining the output power of the engine at the current moment according to the preset maximum descending power change slope of the engine, the preset time length and the output power of the engine at the last moment, wherein the method comprises the following steps:

and calculating the output power of the engine at the current moment according to the product of the preset maximum descending power change slope of the engine and the preset duration and the sum of the output power of the engine at the previous moment.

Specifically, when the change slope R of the engine power required by the system is larger than the preset maximum descending power change slope R of the engine_uWhen the current time is longer, the output power P of the engine is obtained_m(t) is:

P_m(t)＝T_s*R_u+P_m(t-1)

then, the output power P of the engine at the current moment is obtained_m(t) and the total propulsion power required by the system at the current moment is P_P(t) the power P to be output or input by the current energy storage module can be calculated_e(t)。

P_e(t)＝P_p(t)-P_m(t)

If the power P of the energy storage module is present_eAnd (t) when the power variation rate is larger than zero, the control module controls the energy storage module to discharge and output power by controlling the shaft motor so as to compensate the difference value that the power variation rate actually provided by the engine is smaller than the power variation rate required by the system, thereby meeting the power variation rate of the engine required by the system.

Optionally, when the change slope of the engine power required by the system is smaller than the preset maximum rising power change slope of the engine, controlling the shaft to charge the energy storage module with the motor, including:

determining the output power of the engine at the current moment according to the preset maximum rising power change slope of the engine, the preset duration and the output power of the engine at the previous moment;

and determining the charging electric quantity of the energy storage module according to the output power of the engine at the current moment and the total propulsion power required by the system at the current moment.

Optionally, determining the output power of the engine at the current moment according to the preset maximum ascending power change slope of the engine, the preset time length and the output power of the engine at the last moment, wherein the method comprises the following steps:

and calculating the output power of the engine at the current moment according to the product of the preset maximum ascending power change slope of the engine and the preset duration and the sum of the output power of the engine at the previous moment.

Specifically, when the change slope R of the engine power required by the system is smaller than the preset maximum rising power change slope R of the engine_dWhen the current time is longer, the output power P of the engine is obtained_m(t) is:

P_m(t)＝T_s*R_d+P_m(t-1)

then, the output power P of the engine at the current moment is obtained_m(t) and the total propulsion power required by the system at the current moment is P_P(t) the power P to be output or input by the current energy storage module can be calculated_e(t)。

P_e(t)＝P_p(t)-P_m(t)

If the power P of the energy storage module is present_e(t) is less than zero, then the control module takes the motor to control the energy storage module to charge through the control shaft, so that the redundant power that the engine can actually output is stored by charging the energy storage module, the utilization rate of energy is improved, the energy is saved, and the resource waste is avoided.

In addition, when the change slope of the engine power required by the system is larger than the preset maximum rising power change slope of the engineWhen the power change rate is smaller than the preset maximum descending power change slope of the engine, namely the power change rate which can be actually provided by the engine just meets the power change rate required by the system, the control module controls the shaft motor to stop working, at the moment, the energy storage module is not discharged or charged, and the output power P of the engine at the current moment_m(t) is:

P_m(t)＝P_p(t)

in the technical solution of the present embodiment, referring to fig. 3, the principle of the control method of the marine engine propulsion system is as follows: firstly, a preset maximum descending power change slope of the engine is set to be R through a control module according to the combustion performance of the engine_dAnd presetting the maximum rising power change slope as R_u. Acquiring total propulsion power P required by system at current moment_p(t) and the output power P of the engine at the previous moment_m(t-1) and advancing the total power P according to the system requirement at the current moment_p(t) and the output power P of the engine at the previous moment_m(t-1) calculating the change slope R of the engine power required by the system. Then judging whether the change slope R of the engine power required by the system is larger than the preset maximum descending power change slope R of the engine or not_uIf yes, changing the slope R according to the preset maximum descending power of the engine_uAnd a preset duration T_sThe product of (a) and the output power P of the engine at the previous moment_mThe sum of (t-1) can calculate the output power P of the engine at the current moment_m(t) then obtaining the output power P of the engine at the current time_m(t) and the total propulsion power required by the system at the current moment is P_P(t) the power P to be output or input by the current energy storage module can be calculated_e(t) if the power P of the energy storage module is present_eAnd (t) is larger than zero, the control module controls the energy storage module to discharge through the control shaft with the motor. If the change slope R of the engine power required by the system is smaller than the preset maximum descending power change slope R of the engine_uThen, whether the change slope R of the engine power required by the system is smaller than the preset maximum rising power change slope R of the engine is further judged_dIf yes, changing the slope R according to the preset maximum rising power of the engine_dAnd a preset duration T_sThe product of (a) and the output power P of the engine at the previous moment_mThe sum of (t-1) can calculate the output power P of the engine at the current moment_m(t) then obtaining the output power P of the engine at the current time_m(t) and the total propulsion power required by the system at the current moment is P_P(t) the power P to be output or input by the current energy storage module can be calculated_e(t) if the power P of the energy storage module is present_eAnd (t) is less than zero, the control module controls the energy storage module to charge through the control shaft with the motor. Therefore, when the load change of the propulsion system is large, and the power change rate of the system requirement is large, the power change amplitude of the engine can be reduced, the knocking is reduced, the particulate matter emission is reduced, and meanwhile, the utilization rate of energy is improved according to the condition met by the power change slope of the engine required by the system and the charging or discharging of the energy storage module is controlled by controlling the shaft motor.

EXAMPLE III

An embodiment of the present invention further provides a marine engine propulsion system, as shown in fig. 1, including: the shaft motor, the energy storage module and the control module are arranged; the engine is connected with the shaft motor, the shaft motor is connected with the energy storage module, and the control module is connected with the shaft motor and the engine;

the control module is used for determining the power change slope of the engine required by the system according to the total propulsion power required by the system at the current moment and the output power of the engine at the previous moment; and when the change slope of the engine power required by the system meets a preset condition, controlling the energy storage module to charge or discharge through controlling the shaft-driven motor.

The output of the shaft motor 20 is connected to a load, for example to a propeller 1 with a fixed pitch. The shaft motor 20 is used for outputting power to drive the propeller 1 to rotate.

The engine 10 may be a two-stroke low-pressure dual-fuel engine, which has advantages of low natural gas intake pressure, simple gas supply system structure, low nitrogen oxide emission, low cost, and the like. The energy storage module 30 may be an energy storage battery, such as a rechargeable lithium battery. The energy storage module 30 is bidirectionally connected with the shaft motor 20, and can realize charging and discharging functions. The control module 40 may be a single chip microcomputer, a PLC controller, etc.

In the technical scheme of the embodiment, the propulsion system comprises a shaft motor, an energy storage module and a control module, wherein the engine is connected with the shaft motor, the shaft motor is connected with the energy storage module, the control module is connected with the shaft motor and the engine, and the control module is used for determining the power change slope of the engine required by the system according to the total propulsion power required by the system at the current moment and the output power of the engine at the last moment; when the change slope of the engine power required by the system meets a preset condition, the energy storage module is controlled to charge or discharge through the control shaft motor. The system can solve the problems that the existing marine engine is easy to knock, has large system power consumption and the like when the propulsion load changes frequently. When the change slope of the engine power required by the system meets the preset condition, the energy storage module is controlled to charge or discharge through the control shaft and the motor, so that the power change amplitude of the engine is reduced when the load change of the propulsion system is large, knocking is reduced, particulate matter emission is reduced, and meanwhile, the utilization rate of energy is improved.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.