阅读说明：本技术 液压混合动力车辆控制方法 (Hydraulic hybrid vehicle control method ) 是由 孙传文 徐锟 贾俊林 于 2019-03-12 设计创作，主要内容包括：本发明提供一种液压混合动力车辆控制方法,包括如下步骤：当车辆的行驶速度大于零,刹车踏板的角位移大于零且小于第一刹车角位移设定值,控制器控制与液压泵/马达相连接的阀组动作,液压泵/马达的排量大于零,转动中的车轮带动液压泵/马达动作,第二蓄能器中的液压油经该液压泵/马达加压后流入第一蓄能器中；当油门踏板的角位移大于零且小于第一油门角位移设定值,控制器控制阀组动作,液压泵/马达的排量大于零,第一蓄能器中的液压油经液压泵/马达流入第二蓄能器中,且第一蓄能器中的液压油驱动液压泵/马达动作,液压泵/马达驱动车轮转动。本液压混合动力车辆控制方法实现了制动能的回收及利用,并保证车辆耗能较低。(The invention provides a hydraulic hybrid vehicle control method, which comprises the following steps: when the running speed of the vehicle is greater than zero, the angular displacement of the brake pedal is greater than zero and smaller than a first brake angular displacement set value, the controller controls a valve group connected with the hydraulic pump/motor to act, the displacement of the hydraulic pump/motor is greater than zero, the rotating wheel drives the hydraulic pump/motor to act, and hydraulic oil in the second energy accumulator flows into the first energy accumulator after being pressurized by the hydraulic pump/motor; when the angular displacement of the accelerator pedal is larger than zero and smaller than a first accelerator angular displacement set value, the controller controls the valve group to act, the displacement of the hydraulic pump/motor is larger than zero, hydraulic oil in the first energy accumulator flows into the second energy accumulator through the hydraulic pump/motor, the hydraulic oil in the first energy accumulator drives the hydraulic pump/motor to act, and the hydraulic pump/motor drives wheels to rotate. The control method of the hydraulic hybrid power vehicle realizes the recovery and the utilization of the braking energy and ensures that the energy consumption of the vehicle is lower.)

1. A hydraulic hybrid vehicle control method characterized by comprising the steps of:

a vehicle speed sensor (743) detects the running speed of the vehicle and sends a running speed signal of the vehicle to a controller (75);

the first angular displacement sensor (741) detects the angular displacement of the brake pedal and sends an angular displacement signal of the brake pedal to the controller (75);

a second angular displacement sensor (745) detects the angular displacement of the accelerator pedal and sends an angular displacement signal of the accelerator pedal to the controller (75);

the pressure sensor (742) detects the pressure of the hydraulic oil in the first accumulator (72) and sends a pressure signal of the hydraulic oil in the first accumulator (72) to the controller (75);

an engine speed sensor (744) detects the speed of the engine (1) and sends a speed signal of the engine (1) to the controller (75);

when the running speed of the vehicle is greater than zero, the angular displacement of a brake pedal is greater than zero and smaller than a first brake angular displacement set value, and the pressure of hydraulic oil in a first energy accumulator (72) is lower than a first pressure set value, a controller (75) controls a valve bank connected with a hydraulic pump/motor (71) to act, the valve bank is connected with the first energy accumulator (72) and a second energy accumulator (73), the displacement of the hydraulic pump/motor (71) is greater than zero, a rotating wheel (6) drives the hydraulic pump/motor (71) to act through a drive axle (5), a speed reducer (4), a transmission shaft (31), a gearbox (3) and a power output device (32), and the hydraulic oil in the second energy accumulator (73) flows into the first energy accumulator (72) after being pressurized by the hydraulic pump/motor (71);

when the running speed of the vehicle is equal to zero, the rotating speed of the engine (1) is greater than zero, and the pressure of hydraulic oil in the first energy accumulator (72) is lower than a first pressure set value, the controller (75) controls the valve set to act, the displacement of the hydraulic pump/motor (71) is greater than zero, the engine (1) drives the hydraulic pump/motor (71) to act through the gearbox (3) and the power output device (32), and the hydraulic oil in the second energy accumulator (73) flows into the first energy accumulator (72) after being pressurized by the hydraulic pump/motor (71);

when the angular displacement of an accelerator pedal is larger than zero and smaller than a first accelerator angular displacement set value, and the pressure of hydraulic oil in a first energy accumulator (72) is higher than a second pressure set value, a controller (75) controls a valve bank to act, the displacement of a hydraulic pump/motor (71) is larger than zero, the hydraulic oil in the first energy accumulator (72) flows into a second energy accumulator (73) through the hydraulic pump/motor (71), the hydraulic oil in the first energy accumulator (72) drives the hydraulic pump/motor (71) to act, and the hydraulic pump/motor (71) drives wheels (6) to rotate through a power output device (32), a gearbox (3), a transmission shaft (31), a speed reducer (4) and a drive axle (5);

the engine (1) is connected with the gearbox (3), the power output device (32) is installed on the gearbox (3), the power output device (32) is connected with the hydraulic pump/motor (71), the gearbox (3) is connected with the speed reducer (4) through the transmission shaft (31), the speed reducer (4) is connected with the drive axle (5), and the wheels (6) are installed on the drive axle (5).

2. The hydraulic hybrid vehicle control method according to claim 1, wherein when the traveling speed of the vehicle is greater than zero, the angular displacement of the brake pedal is greater than the second braking angular displacement setting value and less than the first braking angular displacement setting value, and the pressure of the hydraulic oil in the first accumulator (72) is lower than the first pressure setting value, the brake pedal actuates the mechanical friction brake, and the mechanical friction brake provides the braking force to the wheels (6); the second braking angular displacement set value is less than the first braking angular displacement set value.

3. The hydraulic hybrid vehicle control method of claim 1, wherein the controller (75) controls the valve set to operate when a traveling speed of the vehicle is greater than zero, an angular displacement of the brake pedal is greater than zero and less than a first brake angular displacement set point, and a pressure of hydraulic oil in the first accumulator (72) is equal to a first pressure set point, and a displacement of the hydraulic pump/motor (71) is equal to zero.

4. The hydraulic hybrid vehicle control method of claim 1, wherein the controller (75) commands valve bank actuation when the angular displacement of the brake pedal is greater than or equal to a first angular brake displacement set point, and the displacement of the hydraulic pump/motor (71) is equal to zero.

5. The hydraulic hybrid vehicle control method according to claim 1, characterized in that when the traveling speed of the vehicle is equal to zero, the rotational speed of the engine (1) is greater than zero, and the pressure of the hydraulic oil in the first accumulator (72) is equal to the first pressure set value, the controller (75) controls the valve group to operate, and the displacement of the hydraulic pump/motor (71) is equal to zero.

6. The hydraulic hybrid vehicle control method according to claim 1, wherein when the angular displacement of the accelerator pedal is greater than a second accelerator angular displacement setting value and less than a first accelerator angular displacement setting value, and the pressure of the hydraulic oil in the first accumulator (72) is higher than a second pressure setting value, the controller (75) controls the engine (1) to operate, and the engine (1) and the hydraulic pump/motor (71) both drive the wheels (6) to rotate through the gearbox (3), the transmission shaft (31), the reducer (4) and the drive axle (5); the second throttle angular displacement set value is smaller than the first throttle angular displacement set value.

7. The hydraulic hybrid vehicle control method of claim 1, wherein when the angular displacement of the accelerator pedal is greater than zero and less than a first angular accelerator displacement setting, and the pressure of the hydraulic oil in the first accumulator (72) is equal to a second pressure setting, the controller (75) controls the valve set to operate such that the displacement of the hydraulic pump/motor (71) is equal to zero.

8. The hydraulic hybrid vehicle control method of claim 1, wherein the controller (75) commands valve bank actuation when the angular displacement of the accelerator pedal is greater than or equal to a first angular throttle displacement set point, and the displacement of the hydraulic pump/motor (71) is equal to zero.

Technical Field

The present invention relates to a control method for a vehicle, and more particularly, to a control method for a hydraulic hybrid vehicle.

Background

The hydraulic hybrid vehicle can recover the braking energy and the idling energy of the vehicle by connecting an engine, a hydraulic pump/hydraulic motor and a hydraulic energy accumulator to an energy output end, store the recovered energy into the hydraulic energy accumulator in the form of hydraulic energy, and can release the energy to drive the vehicle to run together with the energy output by the engine when the vehicle is accelerated, ascends a slope and the like in need of large energy output so as to achieve the purpose of energy saving. Meanwhile, the energy recovery and release mode can also optimize the working point of the engine so as to optimize the fuel efficiency of the engine and further improve the energy-saving efficiency. According to the connection mode of a hydraulic pump/motor and an engine, the hydraulic hybrid vehicle can be divided into a series connection type, a parallel connection type and a series-parallel connection type, and the parallel connection type hydraulic hybrid is a system framework with the most development potential and the key point of the current research in the field of heavy-duty vehicles based on the consideration of oil consumption, efficiency and cost.

At present, in order to further improve the fuel consumption performance and the emission performance of the automobile, a hybrid design method is gradually and commonly applied to the automobile, and various control strategies based on the hybrid automobile, such as optimization control, fuzzy control, PI control, neural network control and the like, are also proposed in succession, which are basically applied to the oil-electric hybrid system, but research based on the hydraulic hybrid system and aiming at energy-saving control is relatively less at present. Compared with oil-electricity hybrid, the hydraulic hybrid power system has the advantages of high power density, high energy charging and discharging speed, long service life, low cost and the like. Therefore, research and development work of the hydraulic hybrid power technology is gradually increased in the field of vehicles, particularly heavy vehicles with high power and frequent start-stop working conditions.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, the present invention provides a control method for a hydraulic hybrid vehicle with low energy consumption.

To achieve the above object, the present invention provides a hydraulic hybrid vehicle control method including the steps of:

the vehicle speed sensor detects the running speed of the vehicle and sends a running speed signal of the vehicle to the controller;

the first angular displacement sensor detects the angular displacement of the brake pedal and sends an angular displacement signal of the brake pedal to the controller;

the second angular displacement sensor detects the angular displacement of the accelerator pedal and sends an angular displacement signal of the accelerator pedal to the controller;

the pressure sensor detects the pressure of the hydraulic oil in the first energy accumulator and sends a pressure signal of the hydraulic oil in the first energy accumulator to the controller;

the engine rotating speed sensor detects the rotating speed of the engine and sends a rotating speed signal of the engine to the controller;

when the running speed of the vehicle is greater than zero, the angular displacement of a brake pedal is greater than zero and less than a first brake angular displacement set value, and the pressure of hydraulic oil in a first energy accumulator is lower than a first pressure set value, a controller controls a valve bank connected with a hydraulic pump/motor to act, the valve bank is connected with the first energy accumulator and a second energy accumulator, the displacement of the hydraulic pump/motor is greater than zero, a rotating wheel drives the hydraulic pump/motor to act through a drive axle, a speed reducer, a transmission shaft, a gearbox and a power output device, and the hydraulic oil in the second energy accumulator flows into the first energy accumulator after being pressurized by the hydraulic pump/motor;

when the running speed of the vehicle is equal to zero, the rotating speed of the engine is greater than zero, and the pressure of hydraulic oil in the first energy accumulator is lower than a first pressure set value, the controller controls the valve group to act, the displacement of the hydraulic pump/motor is greater than zero, the engine drives the hydraulic pump/motor to act through the gearbox and the power output device, and the hydraulic oil in the second energy accumulator flows into the first energy accumulator after being pressurized by the hydraulic pump/motor;

when the angular displacement of the accelerator pedal is larger than zero and smaller than a first accelerator angular displacement set value, and the pressure of hydraulic oil in the first energy accumulator is higher than a second pressure set value, the controller controls the valve group to act, the displacement of the hydraulic pump/motor is larger than zero, the hydraulic oil in the first energy accumulator flows into the second energy accumulator through the hydraulic pump/motor, the hydraulic pump/motor in the first energy accumulator drives the hydraulic pump/motor to act, and the hydraulic pump/motor drives wheels to rotate through the power output device, the gearbox, the transmission shaft, the speed reducer and the drive axle;

the engine is connected with the gearbox, the power output device is installed on the gearbox and connected with the hydraulic pump/motor, the gearbox is connected with the speed reducer through the transmission shaft, the speed reducer is connected with the drive axle, and the wheels are installed on the drive axle.

Further, when the running speed of the vehicle is greater than zero, the angular displacement of the brake pedal is greater than a second brake angular displacement set value and smaller than a first brake angular displacement set value, and the pressure of hydraulic oil in the first energy accumulator is lower than a first pressure set value, the brake pedal drives the mechanical friction brake to act, and the mechanical friction brake provides braking force for the wheel; the second braking angular displacement set value is less than the first braking angular displacement set value.

Further, when the running speed of the vehicle is greater than zero, the angular displacement of the brake pedal is greater than zero and smaller than a first brake angular displacement set value, and the pressure of hydraulic oil in the first energy accumulator is equal to a first pressure set value, the controller controls the valve group to act, and the displacement of the hydraulic pump/motor is equal to zero.

Further, when the angular displacement of the brake pedal is larger than or equal to a first braking angular displacement set value, the controller controls the valve group to act, and the displacement of the hydraulic pump/motor is equal to zero.

Further, when the running speed of the vehicle is equal to zero, the rotating speed of the engine is greater than zero, and the pressure of the hydraulic oil in the first accumulator is equal to a first pressure set value, the controller controls the valve group to act, and the displacement of the hydraulic pump/motor is equal to zero.

Further, when the angular displacement of the accelerator pedal is larger than a second accelerator angular displacement set value and smaller than a first accelerator angular displacement set value, and the pressure of hydraulic oil in the first energy accumulator is higher than a second pressure set value, the controller controls the engine to run, and the engine and the hydraulic pump/motor drive wheels to rotate through the gearbox, the transmission shaft, the speed reducer and the drive axle; the second throttle angular displacement set value is smaller than the first throttle angular displacement set value.

Further, when the angular displacement of the accelerator pedal is larger than zero and smaller than a first accelerator angular displacement set value and the pressure of hydraulic oil in the first energy accumulator is equal to a second pressure set value, the controller controls the valve group to act, and the displacement of the hydraulic pump/motor is equal to zero.

Further, when the angular displacement of the accelerator pedal is larger than or equal to a first accelerator angular displacement set value, the controller controls the valve group to act, and the displacement of the hydraulic pump/motor is equal to zero.

As described above, the hydraulic hybrid vehicle control method according to the present invention has the following advantageous effects:

the control method of the hydraulic hybrid power vehicle converts kinetic energy, namely braking energy, of the vehicle in the braking process into hydraulic energy through the steps and stores the hydraulic energy in the first energy accumulator; meanwhile, idle speed energy of the vehicle under an idle speed working condition, namely mechanical energy output by the engine, is converted into hydraulic energy and stored in the first energy accumulator; and when the vehicle is in a starting, accelerating or climbing state, the hydraulic energy in the first energy accumulator is released and converted into the kinetic energy of the vehicle, so that the recovery and utilization of the braking energy and the idling energy are realized, and the overall energy consumption of the vehicle is lower.

Drawings

Fig. 1 is a schematic structural view of a vehicle according to the present invention.

FIG. 2 is a schematic diagram of the connection structure of the first angular displacement sensor, the controller, the hydraulic pump/motor, and the wheels of the vehicle under braking conditions.

FIG. 3 is a schematic diagram of the connection between the controller, the hydraulic pump/motor, and the engine during idle conditions in accordance with the present invention.

Fig. 4 is a schematic view of the connection structure among the second angular displacement sensor, the controller, the hydraulic pump/motor, and the wheels in the starting, accelerating, or climbing conditions of the present invention.

Description of the element reference numerals

1 Engine 72 first accumulator

2 Clutch 73 second accumulator

3 first angular displacement sensor of gearbox 741

31 drive shaft 742 pressure sensor

Vehicle speed sensor of 32 power output device 743

4-speed reducer 744 engine speed sensor

5 driving bridge 745 second angle displacement sensor

6 wheel 75 controller

71 Hydraulic pump/motor 76 electro-hydraulic control module

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

It should be understood that the structures, ratios, sizes, and the like shown in the drawings are only used for matching the disclosure of the present disclosure, and are not used for limiting the conditions of the present disclosure, so that the present disclosure is not limited to the technical essence, and any modifications of the structures, changes of the ratios, or adjustments of the sizes, can still fall within the scope of the present disclosure without affecting the function and the achievable purpose of the present disclosure. In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for convenience of description only, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention unless otherwise specified.

As shown in fig. 1 to 4, the present invention provides a hydraulic hybrid vehicle control method including the steps of:

the vehicle speed sensor 743 detects a running speed of the vehicle, and transmits a running speed signal of the vehicle to the controller 75;

the first angular displacement sensor 741 detects an angular displacement of the brake pedal, and transmits an angular displacement signal of the brake pedal to the controller 75;

the second angular displacement sensor 745 detects the angular displacement of the accelerator pedal and sends an angular displacement signal of the accelerator pedal to the controller 75;

the pressure sensor 742 detects the pressure of the hydraulic oil in the first accumulator 72 and sends a pressure signal of the hydraulic oil in the first accumulator 72 to the controller 75;

the engine speed sensor 744 detects the rotational speed of the engine 1 and sends a rotational speed signal of the engine 1 to the controller 75;

when the running speed of the vehicle is greater than zero, the angular displacement of the brake pedal is greater than zero and smaller than a first brake angular displacement set value, namely the vehicle is in a brake working condition, and the pressure of hydraulic oil in the first energy accumulator 72 is lower than a first pressure set value, the vehicle is in a brake state at the moment, the controller 75 controls the action of a valve group connected with the hydraulic pump/motor 71, the valve group is connected with the first energy accumulator 72 and the second energy accumulator 73, the displacement of the hydraulic pump/motor 71 is greater than zero, the rotating wheel 6 drives the hydraulic pump/motor 71 to act through the drive axle 5, the speed reducer 4, the transmission shaft 31, the gearbox 3 and the power output device 32, the hydraulic oil in the second energy accumulator 73 is pressurized by the hydraulic pump/motor 71 and then flows into the first energy accumulator 72, and the hydraulic pump/motor 71 serves as a pump;

when the running speed of the vehicle is equal to zero, the rotating speed of the engine 1 is greater than zero, namely the vehicle is in an idle working condition, and the pressure of hydraulic oil in the first energy accumulator 72 is lower than a first pressure set value, the vehicle is in an idle state at the moment, the controller 75 controls the valve group to act, the displacement of the hydraulic pump/motor 71 is greater than zero, the engine 1 drives the hydraulic pump/motor 71 to act through the gearbox 3 and the power output device 32, the hydraulic oil in the second energy accumulator 73 is pressurized by the hydraulic pump/motor 71 and then flows into the first energy accumulator 72, and the hydraulic pump/motor 71 serves as a pump at the moment;

when the angular displacement of the accelerator pedal is larger than zero and smaller than a first accelerator angular displacement set value, and the pressure of hydraulic oil in the first energy accumulator 72 is higher than a second pressure set value, the vehicle is in a starting, accelerating or climbing state at the moment, the controller 75 controls the valve group to act, the displacement of the hydraulic pump/motor 71 is larger than zero, the hydraulic oil in the first energy accumulator 72 flows into the second energy accumulator 73 through the hydraulic pump/motor 71, the hydraulic oil in the first energy accumulator 72 drives the hydraulic pump/motor 71 to act, the hydraulic pump/motor 71 drives the wheels 6 to rotate through the power output device 32, the gearbox 3, the transmission shaft 31, the speed reducer 4 and the drive axle 5, and at the moment, the hydraulic pump/motor 71 serves as a motor;

the engine 1 is connected with the gearbox 3, the power output device 32 is mounted on the gearbox 3, the power output device 32 is connected with the hydraulic pump/motor 71, the gearbox 3 is connected with the speed reducer 4 through the transmission shaft 31, the speed reducer 4 is connected with the drive axle 5, and the wheels 6 are mounted on the drive axle 5.

The control method of the hydraulic hybrid power vehicle converts kinetic energy, namely braking energy, of the vehicle in the braking process into hydraulic energy through the steps and stores the hydraulic energy in the first energy accumulator 72; meanwhile, idle energy of the vehicle under an idle condition, that is, mechanical energy output by the engine 1 is converted into hydraulic energy and stored in the first accumulator 72; when the vehicle is in a starting, accelerating or climbing state, the hydraulic energy in the first energy accumulator 72 is released and converted into the kinetic energy of the vehicle, so that the recovery and utilization of the braking energy and the idle speed energy are realized, and the overall energy consumption of the vehicle is low.

The hydraulic pump/motor 71, the first accumulator 72 and the second accumulator 73 form an energy recycling power system, the energy recycling power system can recycle braking energy in the braking process, and meanwhile braking force is provided for a vehicle in the process. And the energy recovery utilizes the power system to recover the idle energy of the vehicle. In addition, the energy recycling power system releases recycled energy and converts the recycled energy into kinetic energy for vehicle running under the working conditions of starting, accelerating or climbing. The engine 1 in the present embodiment constitutes a main power source of the vehicle; the energy recovery and utilization power system forms an auxiliary power source of the vehicle.

As shown in fig. 2, in this embodiment, when the running speed of the vehicle is greater than zero, the angular displacement of the brake pedal is greater than the second braking angular displacement setting value and less than the first braking angular displacement setting value, and the vehicle is in a normal braking condition at this time, and the pressure of the hydraulic oil in the first energy accumulator 72 is lower than the first pressure setting value, the brake pedal drives the mechanical friction brake to act, and the mechanical friction brake provides a braking force to the wheel 6; the second braking angular displacement set value is less than the first braking angular displacement set value. The present embodiment provides braking force from both the energy recovery powertrain and the mechanical friction brakes during the conventional braking conditions described above. And when the running speed of the vehicle is greater than zero and the angular displacement of the brake pedal is less than or equal to the second braking angular displacement set value, the vehicle is in a slight braking working condition at the moment, and the brake pedal cannot drive the mechanical friction brake to act, so that the energy recycling power system only provides braking force for the vehicle under the slight braking working condition. And the brake pedal has a section of idle stroke, and in a slight braking working condition, the brake pedal rotates in the idle stroke, so that the brake pedal cannot trigger the mechanical friction brake to act, and the energy recycling power system only provides braking force for the vehicle. When the running speed of the vehicle is greater than zero and the angular displacement of the brake pedal is greater than or equal to a first brake angular displacement set value, the vehicle is in an emergency braking working condition at the moment, the controller 75 controls the valve group to perform corresponding actions, so that the displacement of the hydraulic pump/motor 71 is equal to zero, the hydraulic pump/motor 71 and the energy recycling power system cannot recycle energy, the energy recycling power system cannot utilize braking force for the vehicle, and the mechanical friction brake alone provides braking force to rapidly provide braking force for the vehicle.

In this embodiment, when the driving speed of the vehicle is greater than zero, the angular displacement of the brake pedal is greater than zero and less than the first braking angular displacement setting value, and the pressure of the hydraulic oil in the first energy accumulator 72 is equal to the first pressure setting value, the controller 75 controls the valve set to operate, the displacement of the hydraulic pump/motor 71 is equal to zero, and at this time, because the energy stored in the first energy accumulator 72 reaches the upper limit, the controller 75 controls the energy recycling power system to stop recycling the braking energy, so as to prevent the first energy accumulator 72 from being damaged, and ensure the overall safety of the vehicle.

In this embodiment, when the running speed of the vehicle is equal to zero, the rotation speed of the engine 1 is greater than zero, and the pressure of the hydraulic oil in the first accumulator 72 is equal to the first pressure set value, the controller 75 controls the valve group to operate, and the displacement of the hydraulic pump/motor 71 is equal to zero; at this time, since the energy stored in the first accumulator 72 has reached the upper limit, the controller 75 controls the energy recovery power system to stop recovering the idle energy, so as to prevent the first accumulator 72 from being damaged and ensure the overall safety of the vehicle.

As shown in fig. 4, in this embodiment, when the angular displacement of the accelerator pedal is greater than the second accelerator angular displacement setting value and less than the first accelerator angular displacement setting value, and the pressure of the hydraulic oil in the first accumulator 72 is higher than the second pressure setting value, the controller 75 controls the engine 1 to operate, and the engine 1 and the hydraulic pump/motor 71 both drive the wheels 6 to rotate through the gearbox 3, the transmission shaft 31, the reducer 4, and the drive axle 5; the second throttle angular displacement set value is smaller than the first throttle angular displacement set value. In the process, the power system and the engine 1, namely the auxiliary power source and the main power source, are used for supplying power to the vehicle through energy recovery.

In this embodiment, when the angular displacement of the accelerator pedal is greater than zero and smaller than the first angular displacement setting value of the accelerator pedal, and the pressure of the hydraulic oil in the first accumulator 72 is equal to the second pressure setting value, the controller 75 controls the valve set to operate, and the displacement of the hydraulic pump/motor 71 is equal to zero. At this time, since the energy stored in the first accumulator 72 has reached the lower limit, the controller 75 controls the energy recovery power system to stop releasing energy, i.e., the energy recovery power system stops powering the vehicle, and will be powered by the engine 1 alone.

In this embodiment, when the angular displacement of the accelerator pedal is greater than or equal to the first angular displacement setting, the controller 75 controls the valve assembly to operate, and the displacement of the hydraulic pump/motor 71 is equal to zero. At this time, the energy recovery power system is not powered, and is powered by the engine 1 alone.

As shown in fig. 1, in the present embodiment, an output shaft of the engine 1 is connected to a transmission 3 through a clutch 2. In this embodiment, the controller 75 controls the displacement of the hydraulic pump/motor 71 by controlling the valve group operation, and controls the flow direction of the hydraulic oil among the first accumulator 72, the second accumulator 73, and the hydraulic pump/motor 71, thereby controlling the use of the hydraulic pump/motor 71 as a pump or a motor, and controlling whether the first accumulator 72 can recover or release energy.

As shown in fig. 2, in the braking operation, the controller 75 of the hydraulic pump/motor 71 of the controller 75 of the present embodiment calculates the target output torque of the hydraulic pump/motor 71 in real time by using the PI algorithm, and outputs a corresponding signal to control the amount of the output discharge of the hydraulic pump/motor 71 for energy recovery, and controls the amount of the recovered energy by adjusting the amount of the output discharge of the hydraulic pump/motor 71, and the braking force provided during energy recovery is automatically matched with the braking force provided by the original brake, i.e., the mechanical friction brake. The control method of the hydraulic hybrid power vehicle automatically realizes automatic switching and automatic control of multiple working modes such as an independent braking mode of an energy recycling power system, a common braking mode of a mechanical friction brake and the energy recycling power system, an independent braking mode of the mechanical friction brake and the like according to different position signals of a brake pedal. As shown in fig. 3, in the idle condition, the transmission 3 is in neutral, the vehicle speed is zero, the angular displacement of the accelerator pedal is zero, and the engine 1 is in an operating state. In the hydraulic hybrid vehicle control method, the hydraulic pump/motor 71 and the energy recovery power system are used for recovering the idle energy output by the engine 1 so as to ensure the normal operation of the engine 1, namely that the engine 1 does not shut down. And the controller 75 calculates a target output discharge amount of the hydraulic pump/motor 71 in real time and outputs a corresponding signal to control the discharge amount of the hydraulic pump/motor 71. As shown in fig. 4, in the above-mentioned starting, accelerating or climbing operation, the hydraulic pump/motor 71 controller 75 of the controller 75 calculates the target output torque of the hydraulic pump/motor 71 in real time by using the PI algorithm, and outputs a corresponding signal to control the output discharge amount of the hydraulic pump/motor 71, so as to release energy, and control the amount of the released energy by adjusting the output discharge amount of the hydraulic pump/motor 71, and the auxiliary power generated by the energy release is automatically matched with the main power provided by the engine 1. The control method of the hydraulic hybrid vehicle automatically realizes the independent driving mode of the auxiliary power source according to different position signals of the accelerator pedal; the engine 1 and the auxiliary power source are driven together; automatic switching and automatic control of a plurality of drive modes such as a single drive mode of the engine 1.

Additionally, during cruise conditions, the operating mode of the vehicle is the same as that of a conventional vehicle, with the engine 1 alone providing power, and the controller 75 zeroing the displacement of the hydraulic pump/motor 71.

The above-mentioned power output device 32 is abbreviated as PTO in english, and the PTO realizes coupling connection of the auxiliary power source and the main power source to form a parallel hydraulic hybrid system. The transmission 3 is an automatic transmission 3. The speed reducer 4 is a final speed reducer 4. The first accumulator 72 is a high pressure accumulator, the second accumulator 73 is a low pressure accumulator, and the high and low pressure accumulators achieve automatic flow compensation. The output shaft of the engine 1 is connected to the input shaft of a clutch, the output shaft of the clutch is connected to the input shaft of the automatic transmission 3 with the PTO, and the rotational speed of the automatic transmission 3 coincides with the rotational speed of the engine 1. The output shaft of the automatic gearbox 3 is connected with a transmission shaft 31, the transmission shaft 31 is connected with a main speed reducer 4, the main speed reducer 4 is connected with a drive axle 5, and the drive axle 5 is connected with wheels 6. In the present embodiment the drive axle 5 is in particular connected to the rear wheels. The valve block is part of the electro-hydraulic control module 76. The first accumulator 72 is connected to the electro-hydraulic control module 76 via the respective controller 75, and the second accumulator 73 is connected to the electro-hydraulic control module 76. The electro-hydraulic control module 76 is coupled to the controller 75. The controller 75 of the present embodiment employs a PLC.

The control method of the hydraulic hybrid vehicle in the embodiment provides a control strategy of a parallel hydraulic hybrid vehicle, and particularly provides a control method of power source components such as an engine 1, a hydraulic pump/motor 71 and a hydraulic accumulator of the parallel hydraulic hybrid vehicle. The hydraulic hybrid vehicle control method controls the amount of energy recovered and released by controlling the displacement of the hydraulic pump/motor 71 and the output torque thereof, thereby reducing the fuel consumption of the vehicle. The control method of the hydraulic hybrid vehicle utilizes the sensor to realize the automatic identification of the working conditions of braking, acceleration, idling and the like of the vehicle, automatically implement the state switching control on the hydraulic pump/motor 71 and realize the quick and stable control on energy recovery and energy release.

In conclusion, the present invention effectively overcomes various disadvantages of the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.