阅读说明：本技术 一种电静液-飞轮混合储能单元 (Electro-hydrostatic-flywheel hybrid energy storage unit ) 是由 王峰 林梓畅 徐兵 于 2021-09-02 设计创作，主要内容包括：本发明公开了一种电静液-飞轮混合储能单元。本发明包括飞轮、蓄电池、电机控制器、电机、液压泵马达和液压油箱；蓄电池通过电机控制器与电机电连接,电机的输出轴与液压泵马达的输出轴同轴连接,液压泵马达的输出轴还与飞轮的输出轴同轴连接,液压泵马达的第一进出油口与液压油箱连通,液压泵马达的第二进出油口作为混合储能单元的进出油口。本发明当进行小功率充放时,主要由电机将电能和液压能互相转化,飞轮速度只有小的波动；当进行大功率充放时,主要由飞轮将机械能与液压能相互转化,飞轮速度有较大波动。与传统的液压蓄能器储能相比,可实现高功率密度和高能量密度的混合储能。(The invention discloses an electro-hydrostatic-flywheel hybrid energy storage unit. The invention comprises a flywheel, a storage battery, a motor controller, a motor, a hydraulic pump motor and a hydraulic oil tank; the storage battery is electrically connected with the motor through the motor controller, the output shaft of the motor is coaxially connected with the output shaft of the hydraulic pump motor, the output shaft of the hydraulic pump motor is also coaxially connected with the output shaft of the flywheel, a first oil inlet and outlet of the hydraulic pump motor is communicated with the hydraulic oil tank, and a second oil inlet and outlet of the hydraulic pump motor is used as an oil inlet and outlet of the hybrid energy storage unit. When the invention carries out low-power charging and discharging, the electric energy and the hydraulic energy are mainly converted by the motor, and the speed of the flywheel only has small fluctuation; when high-power charging and discharging are carried out, mechanical energy and hydraulic energy are mainly converted by the flywheel, and the speed of the flywheel has large fluctuation. Compared with the traditional hydraulic accumulator energy storage, the hybrid energy storage with high power density and high energy density can be realized.)

1. An electro-hydrostatic-flywheel hybrid energy storage unit, characterized by: comprises a flywheel (1), a storage battery (2), a motor controller (3), a motor (4), a hydraulic pump motor (5) and a hydraulic oil tank (6);

the storage battery (2) is electrically connected with the motor (4) through the motor controller (3), an output shaft of the motor (4) is coaxially connected with an output shaft of the hydraulic pump motor (5), an output shaft of the hydraulic pump motor (5) is also coaxially connected with an output shaft of the flywheel (1), a first oil inlet and outlet of the hydraulic pump motor (5) is communicated with the hydraulic oil tank (6), and a second oil inlet and outlet of the hydraulic pump motor (5) serves as an oil inlet and outlet of the hybrid energy storage unit.

2. An electro-hydrostatic-flywheel hybrid energy storage unit according to claim 1, wherein: the hydraulic pump motor (5) is a single hydraulic pump motor or a combination of two or more hydraulic pump motors.

3. An electro-hydrostatic-flywheel hybrid energy storage unit according to claim 1, wherein: the hydraulic circuit of the hydraulic pump motor (5) is a closed hydraulic circuit or an open hydraulic circuit.

4. An electro-hydrostatic-flywheel hybrid energy storage unit according to claim 1, wherein: the storage battery (2) is a battery pack or a super capacitor.

5. An electro-hydrostatic-flywheel hybrid energy storage unit according to claim 1, wherein: the flywheel (1) is directly connected to an output shaft of the hydraulic pump motor (5) or is connected to the output shaft of the hydraulic pump motor through a clutch or a transmission mechanism.

6. An electro-hydrostatic-flywheel hybrid energy storage unit according to claim 1, wherein: the motor (4) is directly connected with an output shaft of the hydraulic pump motor (5) or is connected with the output shaft of the hydraulic pump motor through a clutch or a transmission mechanism.

7. An electro-hydrostatic-flywheel hybrid energy storage unit according to claim 1, wherein: the power of the hybrid energy storage unit, the power of the flywheel (1) and the power of the motor (4) satisfy the following relation:

P＝P_f+P_e

wherein P is the power of the hybrid energy storage unit, P_fIs the power of the flywheel (1), P_eIs the power of the motor (4).

Technical Field

The invention relates to a hydraulic energy storage unit, in particular to an electro-hydrostatic-flywheel hybrid energy storage unit.

Background

The hydraulic energy storage unit is widely applied to the fields of engineering machinery, vehicles, ocean energy utilization and the like, wherein the most common hydraulic energy storage unit is a hydraulic energy accumulator which has high power density but has the following defects: 1) the energy density is low, the energy storage capacity is small, and the long-time energy release can not be realized; 2) the output hydraulic pressure of the hydraulic accumulator is quickly reduced to be below the pressure required by the system along with the release of the stored energy, so that the working stability of the system is influenced; 3) the energy charging of the energy storage system depends on the main power source, and when the energy storage state is low, a part of power needs to be distributed to charge the energy storage device, so that the power output of a load end can be influenced. The electro-hydrostatic pump can be driven by the motor to work under a pumping working condition, or work under a motor working condition to reversely drag the motor to work as a generator to perform mutual conversion on hydraulic energy and electric energy. The electric energy storage method has higher energy density but lower power density, cannot provide high-power energy charging and discharging, and the flywheel has higher power density and can provide instantaneous high-power charging and discharging but lower energy density.

Disclosure of Invention

In order to solve the above problems in the art, the present invention provides an electro-hydrostatic-flywheel hybrid energy storage unit, which combines flywheel energy storage with high power density and storage battery energy storage with high energy density to realize a hybrid energy storage unit with high energy density and high power density. The hydraulic pump motor 5 is used as an electrostatic liquid pump, a flywheel is connected to a shaft of the electrostatic liquid pump, the hydraulic pump motor can realize the storage and release of hydraulic energy and is integrated into an energy storage unit for use, when small-power charging and discharging are carried out, the electric energy and the hydraulic energy are mainly converted by a motor, and the speed of the flywheel only has small fluctuation; when high-power charging and discharging are carried out, mechanical energy and hydraulic energy are mainly converted by the flywheel, and the speed of the flywheel has large fluctuation.

The technical scheme adopted by the invention is as follows:

the invention comprises a flywheel, a storage battery, a motor controller, a motor, a hydraulic pump motor and a hydraulic oil tank;

the battery passes through the machine controller and is connected with the motor electricity, and the output shaft of motor and hydraulic pump motor's output shaft coaxial coupling, hydraulic pump motor's output shaft still with the output shaft coaxial coupling of flywheel, hydraulic pump motor are provided with two business turn over hydraulic fluid ports, hydraulic pump motor's first business turn over hydraulic fluid port and hydraulic tank intercommunication, hydraulic pump motor's second business turn over hydraulic fluid port is as the business turn over hydraulic fluid port of mixing the energy storage unit.

The hydraulic pump motor is a single hydraulic pump motor or a combination of two or more hydraulic pump motors.

The hydraulic circuit of the hydraulic pump motor is a closed hydraulic circuit or an open hydraulic circuit.

The storage battery is a battery pack or a super capacitor.

The flywheel is directly connected to the output shaft of the hydraulic pump motor or connected to the output shaft of the hydraulic pump motor through a clutch or a transmission mechanism.

The motor is directly connected with the output shaft of the hydraulic pump motor or connected with the output shaft of the hydraulic pump motor through a clutch or a transmission mechanism.

The power of the hybrid energy storage unit, the power of the flywheel and the power of the motor meet the following relation:

P＝P_f+P_e

wherein P is the power of the hybrid energy storage unit, P_fIs the power of the flywheel, P_eIs the power of the motor.

The flywheel provides high-power energy charging and discharging in a short time, and the electro-hydrostatic pump provides long-time low-power energy charging and discharging so as to meet the requirements of the energy storage system under different working conditions. When a large amount of energy needs to be absorbed in a short time, the flywheel can directly absorb high-power energy and release the energy when needed, or the flywheel can be used as a buffer to temporarily store the high-power energy, and then the motor generates electricity with low power and converts the electricity into electric energy to be stored; when the speed of the flywheel is low, the motor can accelerate the flywheel with low power for a long time, and the flywheel can be released once when the system needs high-power discharging.

The invention has the beneficial effects that:

the electric energy storage has high energy density, the flywheel energy storage has high power density but low energy density, the flywheel is connected to a shaft of the electro-static liquid pump, the electro-static liquid pump provides low-power long-time hydraulic energy charging and discharging, and the flywheel provides short-time high-power hydraulic energy charging and discharging. When a large amount of energy needs to be absorbed in a short time, the flywheel can directly absorb high-power energy and release the energy when needed, or the flywheel can be used as a buffer to temporarily store the high-power energy, and then the motor generates electricity with low power and converts the electricity into electric energy to be stored; when the speed of the flywheel is low, the motor can accelerate the flywheel with low power for a long time, and the flywheel can be released once when the system needs high-power discharging. The integrated design can reduce the volume of the energy storage unit and is conveniently integrated into the design of a hydraulic system. Compared with the traditional hydraulic accumulator energy storage, the hybrid energy storage with high power density and high energy density can be realized.

Drawings

Fig. 1 is a schematic diagram of an electro-hydrostatic-flywheel hybrid energy storage unit.

Fig. 2 is a schematic diagram of a series hydraulic hybrid system of the present invention for wheel drive of a wheel loader.

Fig. 3 is a schematic diagram of a front parallel hybrid system of the gearbox for wheel type driving of the wheel loader.

Fig. 4 is a schematic diagram of the rear parallel hybrid system of the gearbox for wheel type driving of the wheel loader according to the invention.

FIG. 5 is a schematic diagram of a front parallel hybrid transmission system of the present invention when used in a truck powertrain.

FIG. 6 is a schematic diagram of a transmission rear parallel hybrid system of the present invention when used in a truck powertrain.

In the figure: 1. the system comprises a flywheel, 2, a storage battery, 3, a motor controller, 4, a motor, 5, a hydraulic pump motor, 6, a hydraulic oil tank, 7, a main hydraulic pump, 8, a hydraulic motor, 9, a vehicle main speed reducer, 10, an engine, 11, a hydraulic torque converter, 12, a gearbox, 13, a meshing gear pair, 14, a first clutch and 15 a second clutch.

Detailed Description

The invention is described in further detail below with reference to the figures and the embodiments.

As shown in fig. 1, the present invention includes a flywheel 1, a storage battery 2, a motor controller 3, a motor 4, a hydraulic pump motor 5, and a hydraulic oil tank 6;

the battery 2 is connected with motor 4 electricity through machine controller 3, the output shaft of motor 4 and hydraulic pump motor 5's output shaft coaxial coupling, hydraulic pump motor 5's output shaft still with flywheel 1's output shaft coaxial coupling, hydraulic pump motor 5 is provided with two business turn over hydraulic fluid ports, hydraulic pump motor 5's first business turn over hydraulic fluid port and hydraulic tank 6 intercommunication, hydraulic pump motor 5's second business turn over hydraulic fluid port is as the first business turn over hydraulic fluid port of mixing the energy storage unit, in the concrete implementation, hydraulic pump motor 5's first business turn over hydraulic fluid port is as or not as the second business turn over hydraulic fluid port of mixing the energy storage unit.

The hydraulic pump motor 5 is a single hydraulic pump motor, or a combination of two or more hydraulic pump motors.

The hydraulic circuit of the hydraulic pump motor 5 is either a closed hydraulic circuit or an open hydraulic circuit.

The hydraulic pump motor 5 is a variable displacement hydraulic pump motor.

The storage battery 2 is a battery pack or a super capacitor.

The flywheel 1 is connected to the output shaft of the hydraulic pump motor 5 directly or through a clutch or a transmission mechanism.

The motor 4 is directly connected with the output shaft of the hydraulic pump motor 5 or connected with the output shaft of the hydraulic pump motor 5 through a clutch or a transmission mechanism.

The power of the hybrid energy storage unit and the power of the flywheel 1 and the motor 4 satisfy the following relation:

P＝P_f+P_e

wherein P is the power of the hybrid energy storage unit, P_fIs the power of the flywheel 1, P_eIs the power of the motor 4.

The flywheel is connected to a shaft of the electro-static liquid pump, low-power long-time hydraulic energy charging and discharging is provided through the electro-static liquid pump, and short-time high-power hydraulic energy charging and discharging is provided through the flywheel. When a large amount of energy needs to be absorbed in a short time, the flywheel can directly absorb high-power energy and release the energy when needed, or the flywheel can be used as a buffer to temporarily store the high-power energy, and then the motor generates electricity with low power and converts the electricity into electric energy to be stored; when the speed of the flywheel is low, the motor can accelerate the flywheel with low power for a long time, and the flywheel can be released once when the system needs high-power discharging.

The embodiment of the invention used for different power systems and the implementation working process thereof are as follows:

example 1

Fig. 2 is a schematic diagram of a series hydraulic hybrid system for a wheel loader travel drive of the present invention. The wheel loader is widely applied engineering machinery, a common hydrostatic transmission system for walking and driving of small and medium-sized wheel loaders is applied to the hydrostatic transmission system of the wheel loader.

The hydrostatic transmission system comprises a main hydraulic pump 7, a hydraulic motor 8, a vehicle main speed reducer 9 and an engine 10, an output shaft of the engine 10 is coaxially connected with an output shaft of the main hydraulic pump 7, two oil inlet and outlet ports of the main hydraulic pump 7 are respectively communicated with two oil inlet and outlet ports of the hydraulic motor 8, the main hydraulic pump 7 and the hydraulic motor 8 form a hydrostatic transmission loop, the output shaft of the hydraulic motor 8 is connected with the vehicle main speed reducer 9 through a transmission shaft, and an oil pipe connected between the main hydraulic pump 7 and the hydraulic motor 8 is communicated with a first oil inlet and outlet port of an electro-hydraulic hybrid energy storage unit. The hydraulic circuit of the hydraulic pump motor 5 of the electro-hydraulic hybrid energy storage unit in this embodiment is an open hydraulic circuit.

The main power source is an engine 10, drives a main hydraulic pump 7, drives a hydraulic motor 8 through a hydrostatic transmission circuit, drives a vehicle main speed reducer 9 through the hydraulic motor 8, and finally drives vehicle wheels to run through the vehicle main speed reducer 9. The parallel hybrid energy storage unit can ensure that the hydraulic pressure of the hydrostatic transmission loop is in a relatively stable level on one hand by controlling the hydraulic pressure of the oil inlet and the oil outlet and the flow of the oil inlet and the oil outlet, and reduce system vibration caused by sudden pressure change; on the other hand, the power matching of the engine and the load can be adjusted through energy charging and discharging, the problem that the power matching of the engine and the load is poor when the load speed changes too fast so that the working condition of the engine is worsened is solved, and the main power source can work stably. Meanwhile, the hybrid energy storage unit can recover braking energy and provide auxiliary power, and the engine works in a higher efficiency range in a mode of energy storage and reutilization.

Example 2

Fig. 3 is a schematic diagram of a front parallel hybrid system of a gearbox for a wheel loader travel drive according to the present invention. For medium and large wheel loaders, the common drive train is hydrodynamic drive + gear shifting.

The power transmission system comprises a hydraulic motor 8, a vehicle main speed reducer 9, an engine 10, a hydraulic torque converter 11, a gearbox 12 and a meshing gear pair 13;

two oil inlets and outlets of the hydraulic motor 8 are respectively communicated with a first oil inlet and outlet and a second oil inlet and outlet of the electro-hydraulic hybrid energy storage unit, and the second oil inlet and outlet of the electro-hydraulic hybrid energy storage unit (i.e. the first oil inlet and outlet of the hydraulic pump motor 5) is not communicated with the hydraulic oil tank, i.e. the hydraulic circuit of the hydraulic pump motor 5 is a closed hydraulic circuit. The hydraulic pump motor 5 and the hydraulic motor 8 constitute a hydrostatic transmission circuit.

Two gears of the meshing gear pair 13 are meshed to form a gear pair, an output shaft of the hydraulic motor 8 is coaxially connected with one gear of the meshing gear pair 13, the other gear of the meshing gear pair 13 is respectively coaxially connected with an output shaft of the hydraulic torque converter 11 and an input shaft of the gearbox 12, the hydraulic torque converter 11 and the gearbox 12 are respectively arranged on two sides of the meshing gear pair 13, the input shaft of the hydraulic torque converter 11 is coaxially connected with an output shaft of the engine 10, the output shaft of the gearbox 12 is coaxially connected with the vehicle main speed reducer 9, and the output shaft of the hydraulic torque converter 11 and the input shaft of the gearbox 12 which are coaxially connected with the meshing gear pair 13 are both used as transmission shafts of the power transmission system.

The hydraulic energy of the electro-hydrostatic-flywheel hybrid energy storage unit can be converted into mechanical energy through the hydraulic motor 8 and be collected into the main power transmission shaft, and the redundant mechanical energy output by the engine 10 can be converted into hydraulic energy and stored in the energy storage unit. On one hand, the working point of the engine can be adjusted to a high-efficiency working area through the storage and release of energy, the fuel economy is improved, and the exhaust emission is reduced; on the other hand, the hydraulic motors 8 connected in parallel can be used as auxiliary power, and can play a role in starting, stopping, accelerating, decelerating and other working conditions by utilizing the characteristics of quick response and high power density of the hydraulic power, so that the power performance and the manipulation performance of the wheel loader are improved.

Example 3

Fig. 4 is a schematic diagram of the rear parallel hybrid system of the gearbox for the wheel loader travel drive of the present invention. The main difference from embodiment 2 is that the position of the hydraulic motor 8 connected in parallel to the main drive shaft is different, and the operating conditions are also different. Compared with the parallel hybrid before the gearbox, the rotating speed of the parallel after the gearbox is lower and the torque requirement is higher, the rotating speed of the hydraulic motor 8 is lower.

The power transmission system comprises a hydraulic motor 8, a vehicle main speed reducer 9, an engine 10, a hydraulic torque converter 11, a gearbox 12 and a meshing gear pair 13;

two oil inlets and outlets of the hydraulic motor 8 are respectively communicated with a first oil inlet and outlet and a second oil inlet and outlet of the electro-hydraulic hybrid energy storage unit, and the second oil inlet and outlet of the electro-hydraulic hybrid energy storage unit (i.e. the first oil inlet and outlet of the hydraulic pump motor 5) is not communicated with the hydraulic oil tank, i.e. the hydraulic circuit of the hydraulic pump motor 5 is a closed hydraulic circuit. The hydraulic pump motor 5 and the hydraulic motor 8 constitute a hydrostatic transmission circuit.

Two gears of the meshing gear pair 13 are meshed to form a gear pair, an output shaft of the hydraulic motor 8 is coaxially connected with one gear of the meshing gear pair 13, the other gear of the meshing gear pair 13 is respectively coaxially connected with an output shaft of the gearbox 12 and a connecting shaft of the vehicle main reducer 9, the vehicle main reducer 9 and the gearbox 12 are respectively arranged on two sides of the meshing gear pair 13, the engine 10 is coaxially connected with an input shaft of the gearbox 12 through a hydraulic torque converter 11, and the output shaft of the gearbox 12 and the connecting shaft of the vehicle main reducer 9 which are coaxially connected with the meshing gear pair 13 are both used as transmission shafts of a power transmission system.

The hydraulic energy of the electro-hydrostatic-flywheel hybrid energy storage unit can be converted into mechanical energy through the hydraulic motor 8 and be collected into the main power transmission shaft, and the redundant mechanical energy output by the engine 10 can be converted into hydraulic energy and stored in the hybrid energy storage unit. Likewise, on the one hand, by storing and releasing energy, the engine operating point can be adjusted to a high-efficiency operating region, fuel economy is improved, and exhaust emission is reduced; on the other hand, the hydraulic motors 8 connected in parallel can be used as auxiliary power, and can play a role in starting, stopping, accelerating, decelerating and other working conditions by utilizing the characteristics of quick response and high power density of the hydraulic power, so that the power performance and the manipulation performance of the wheel loader are improved.

Example 4

FIG. 5 is a schematic diagram of a front parallel hybrid transmission system of the present invention when used in a truck powertrain. Heavy-duty trucks also have a high demand on power performance, and particularly under the working conditions of starting, braking, ascending and the like, a power system needs to adapt to the low-speed working condition and the high-speed working condition of long-distance transportation at the same time, and the demands on an engine and a gearbox are high. Meanwhile, a large amount of braking energy is wasted when the truck is in a long-distance downhill, and an auxiliary heat dissipation device of a brake pad needs to be assembled.

The truck power system comprises a hydraulic motor 8, a vehicle final drive 9, an engine 10, a gearbox 12, a meshing gear pair 13, a first clutch 14 and a second clutch 15;

two oil inlets and outlets of the hydraulic motor 8 are respectively communicated with a first oil inlet and outlet and a second oil inlet and outlet of the electro-hydraulic hybrid energy storage unit, and the second oil inlet and outlet of the electro-hydraulic hybrid energy storage unit (i.e. the first oil inlet and outlet of the hydraulic pump motor 5) is not communicated with the hydraulic oil tank, i.e. the hydraulic circuit of the hydraulic pump motor 5 is a closed hydraulic circuit. The hydraulic pump motor 5 and the hydraulic motor 8 constitute a hydrostatic transmission circuit.

Two gears of the meshing gear pair 13 are meshed to form a gear pair, an output shaft of the hydraulic motor 8 is coaxially connected with one gear of the meshing gear pair 13 through a second clutch 15, the other gear of the meshing gear pair 13 is respectively coaxially connected with an input shaft of the gearbox 12 and an output shaft of the first clutch 14, the first clutch 14 and the gearbox 12 are respectively arranged on two sides of the meshing gear pair 13, the engine 10 is coaxially connected with the input shaft of the first clutch 14, and the output shaft of the gearbox 12 is coaxially connected with the main speed reducer 9 of the vehicle; the input shaft of the transmission case 12 and the output shaft of the first clutch 14, which are coaxially connected to the meshing gear pair 13, both serve as transmission shafts of the power transmission system.

On one hand, under the low-speed working conditions of starting and stopping, accelerating and decelerating, ascending and the like, the second clutch 15 is connected, the parallel hydraulic motor 8 provides auxiliary power, the power performance and the operation performance of the truck are improved by utilizing the quick response and high power density characteristics of the hydraulic power, and under the high-speed working condition, the second clutch 15 is disconnected, so that the work of an engine is not influenced; on the other hand, under the working conditions of braking, long-distance downhill and the like, the second clutch 15 is switched on, braking energy is recovered while braking force is provided, mechanical energy on the transmission shaft is converted and stored into the electro-hydrostatic-flywheel hybrid energy storage unit through the hydraulic motor 8, and is released under the working conditions of auxiliary starting and the like, so that the energy efficiency is improved, and meanwhile, the heat generated by braking is reduced.

Example 5

FIG. 6 is a schematic diagram of a transmission rear parallel hybrid system of the present invention when used in a truck powertrain. The main difference from embodiment 4 is that the position of the hydraulic motor 8 connected in parallel to the main drive shaft is different, and the operating conditions are also different. Compared with the parallel hybrid operation before the gearbox, the rotating speed of the hydraulic motor 8 is lower and the torque requirement is higher.

The truck power system comprises a hydraulic motor 8, a vehicle final drive 9, an engine 10, a gearbox 12, a meshing gear pair 13, a first clutch 14 and a second clutch 15;

two oil inlets and outlets of the hydraulic motor 8 are respectively communicated with a first oil inlet and outlet and a second oil inlet and outlet of the electro-hydraulic hybrid energy storage unit, and the second oil inlet and outlet of the electro-hydraulic hybrid energy storage unit (i.e. the first oil inlet and outlet of the hydraulic pump motor 5) is not communicated with the hydraulic oil tank, i.e. the hydraulic circuit of the hydraulic pump motor 5 is a closed hydraulic circuit. The hydraulic pump motor 5 and the hydraulic motor 8 constitute a hydrostatic transmission circuit.

Two gears of the meshing gear pair 13 are meshed to form a gear pair, an output shaft of the hydraulic motor 8 is coaxially connected with one gear of the meshing gear pair 13 through a second clutch 15, the other gear of the meshing gear pair 13 is respectively and coaxially connected with an output shaft of the gearbox 12 and a connecting shaft of the vehicle main reducer 9, the vehicle main reducer 9 and the gearbox 12 are respectively arranged on two sides of the meshing gear pair 13, the engine 10 is coaxially connected with an input shaft of the gearbox 12 through a first clutch 14, and the output shaft of the gearbox 12 and the connecting shaft of the vehicle main reducer 9 which are coaxially connected with the meshing gear pair 13 are both used as transmission shafts of the power transmission system.

Similarly, on one hand, when the truck is in low-speed working conditions such as start-stop, acceleration and deceleration, uphill and the like, the second clutch 15 is connected, the parallel hydraulic motor 8 provides auxiliary power, the power performance and the handling performance of the truck are improved by utilizing the characteristics of quick response and high power density of the hydraulic power, and the second clutch 15 is disconnected under the high-speed working condition without influencing the work of an engine; on the other hand, under the working conditions of braking, long-distance downhill and the like, the second clutch 15 is switched on, braking energy is recovered while braking force is provided, mechanical energy on the transmission shaft is converted and stored into the electro-hydrostatic-flywheel hybrid energy storage unit through the hydraulic motor 8, and is released under the working conditions of auxiliary starting and the like, so that the energy efficiency is improved, and meanwhile, the heat generated by braking is reduced.