CN105291861B - A kind of electrohydraulic mixed power transmission system - Google Patents

Abstract

The invention discloses a novel electro-hydraulic hybrid power transmission system for a car, which comprises an electric drive system, a coupling mechanism and a hydraulic drive system, and the hydraulic drive system is connected with the coupling mechanism through a clutch. The new electro-hydraulic hybrid power transmission system applied to cars in the present invention is a hydraulic drive system composed of a hydraulic pump/motor, high and low pressure accumulators, hydraulic valves and a hydraulic controller on the basis of the original pure electric vehicle transmission system , can recover and utilize braking energy more effectively, avoid the impact of high current charging and discharging on the cycle life of the battery, reduce the electric loss of the motor and reduce the wear of the brake friction plate.

Description

An electro-hydraulic hybrid power transmission system

technical field

The invention relates to the technical field of electric vehicles, in particular to a novel electro-hydraulic hybrid power transmission system for cars.

Background technique

At present, domestic pure electric vehicles have problems such as short mileage of a single charge, high price, and cannot meet the needs of long-distance journeys, and the charging facilities are not perfect at present. In order to increase the mileage of pure electric vehicles, it is necessary to increase battery capacity. The increase in battery capacity will greatly increase the cost of vehicle manufacturing. In addition, due to the low power density of the battery, the dynamic response of the car will be slow when starting or braking, and the power performance and braking performance of the car cannot be fully utilized. In order to increase the mileage of a single-charge battery, in today's battery technology is difficult to break through, major car manufacturers have considered energy recovery systems. The result of using electric energy recovery is to increase the continuous driving ability of pure electric vehicles, but it also exposes some problems. For example, when the generator starts to brake, the charging current of the battery will be relatively large, and high current charging will have a negative impact on the cycle life of the battery. It has a great impact, and when the vehicle starts, accelerates, climbs and other working conditions, the discharge current of the battery will also be very large, which will also have an impact on the life of the battery, so people have considered the auxiliary energy recovery system (also the auxiliary braking system) /Drive System).

The current auxiliary energy recovery systems that can be used in pure electric vehicles mainly include hydraulic energy storage systems and supercapacitor energy storage systems. Both supercapacitors and hydraulic energy storage have the advantages of high power density, which can avoid the impact of high current charging and discharging on the battery. However, the internal resistance of the supercapacitor is too small, which makes the battery difficult to manage, difficult to match with the battery parameters, and has poor safety and high cost.

Contents of the invention

In view of this, the purpose of the present invention is to provide a novel electro-hydraulic hybrid power transmission system that can avoid the impact of high current charging and discharging on the cycle life of the battery and improve the mileage of the car.

The object of the present invention is achieved through the following technical solutions, a novel electro-hydraulic hybrid transmission system for cars, including an electric drive system and a coupling mechanism 1, and also includes a hydraulic drive system, which is connected to the coupling mechanism through a clutch 2 .

Further, the hydraulic drive system includes a hydraulic pump/motor 4, a hydraulic pump/motor control circuit, a high-pressure accumulator 12 and a low-pressure accumulator 14, and the hydraulic pump/motor control circuit includes a hydraulic pump/motor operating mode control circuit and the hydraulic pump/motor swash plate inclination control circuit, the power output end of the hydraulic pump/motor is connected to the clutch, and the oil outlet of the hydraulic pump/motor is respectively connected to the first oil port of the hydraulic pump/motor working mode control circuit 1. The oil port connection of the low-pressure accumulator, the oil inlet port of the hydraulic pump/motor is connected with the second oil port of the hydraulic pump/motor work mode control circuit, the third oil port of the hydraulic pump/motor work mode control circuit The ports are respectively connected with the oil port of the high-pressure accumulator and the oil port of the hydraulic pump/motor swash plate inclination control circuit.

Further, the hydraulic pump/motor working mode control circuit includes a first electromagnetic reversing valve 5, a first cartridge valve 10, a second cartridge valve 11 and a third electromagnetic reversing valve 13, the first electromagnetic reversing valve The oil inlet of the valve 5 is respectively connected with the oil discharge port of the hydraulic pump/motor, the oil inlet of the third electromagnetic reversing valve 13, the side oil port of the second cartridge valve 11, and the oil port of the low pressure accumulator 14, The oil outlet of the first electromagnetic reversing valve 5 is respectively connected with the side oil port of the first cartridge valve 10, the bottom oil port of the second cartridge valve 11, and the oil port of the high-pressure accumulator 12 through the check valve. , the oil control end of the second cartridge valve 11 is connected to the oil outlet of the third electromagnetic reversing valve 13, the bottom oil port of the first cartridge valve 10 is connected to the oil inlet of the hydraulic pump/motor, the second The oil control end 10 of a cartridge valve is connected with the oil outlet of the first electromagnetic reversing valve 5 .

Further, the hydraulic pump/motor swash plate inclination control circuit includes a hydraulic cylinder 3, a pressure reducing valve 9 and a second electromagnetic reversing valve 8, the oil inlet of the pressure reducing valve is connected to the oil port of the high-pressure accumulator, The oil outlet of the pressure reducing valve is connected to the P port of the second electromagnetic reversing valve, the O port of the second electromagnetic reversing valve is connected to the oil tank, and the A port of the second electromagnetic reversing valve is connected to the hydraulic cylinder The oil inlet port of the second electromagnetic reversing valve is connected with the oil outlet port of the hydraulic cylinder, and the piston rod of the hydraulic cylinder is mechanically connected with the swash plate of the hydraulic pump/motor.

Further, the power of the electric drive system is greater than the power of the hydraulic drive system.

Further, the coupling mechanism is torque coupling or rotational speed coupling.

Further, the mode in which the hydraulic system participates in the work is as follows:

Ⅰ) Cold start, the motor 6 does not start first, the first electromagnetic reversing valve 5 is placed in the right position, the high-pressure accumulator 12 releases high-pressure oil, drives the hydraulic motor 4 to rotate, and then drives the transmission system through the coupling mechanism 1, thereby making Automobile starts, and when reaching motor starting speed, motor 6 starts, clutch 2 is disconnected, hydraulic motor 4 displacement is set to zero, and first electromagnetic reversing valve 5 is placed in the left position;

Ⅱ) Accelerate or climb a slope. When accelerating or climbing a slope, in order to better exert the power performance of the vehicle, place the solenoid valve 5 in the right position to release the oil of the high-pressure accumulator 12, drive the hydraulic motor 4 to rotate, and assist the motor Drive the car to accelerate or climb a slope;

Ⅲ) Deceleration braking, when the vehicle decelerates and brakes, the clutch 2 is engaged, the pump 4 rotates, and the oil in the low-pressure accumulator 14 is pumped into the high-pressure accumulator 12 to store the hydraulic energy and generate resistance torque to prevent the vehicle from running. Produces a braking effect; when the pressure of the high-voltage accumulator 12 reaches its maximum working pressure, the clutch 2 is disconnected, and the motor 6 is used as a generator to charge the battery 7. While generating electricity, a resistance torque is generated to prevent the vehicle from running, thereby producing a braking effect ;

Ⅳ) Liquid filling when driving, when the driving power required by the vehicle is not large, the clutch 2 is engaged, and the motor 1 drives the vehicle to drive the hydraulic pump 4 to rotate at the same time, hydraulically injecting the oil from the low-pressure accumulator 14 into the high-pressure accumulator 12 for storage Hydraulic energy, convenient for the next cold start;

V) unloading, the third electromagnetic reversing valve 13 is placed in the left position, the high-pressure accumulator 12 and the low-pressure accumulator 14 are connected, and the hydraulic circuit is unloaded.

Further, the mode control logic of the hydraulic system participating in the work is as follows:

a) The driving modes in which the hydraulic system participates include cold start mode, normal driving, acceleration or climbing mode, and its control logic includes:

In the cold start mode, when P<P _min , it is motor start; when P>P _min , it is hydraulic start; when it is hydraulic start, when the vehicle speed V is greater than or equal to V1, it is converted to motor start;

In normal driving mode, when P<P _min , it is driving fluid; when P>P _min , it is motor driven;

In acceleration or climbing mode, when P<P _min , it is motor driven; when P>P _min , and V is greater than or equal to V2 or T is greater than or equal to T1, it is hydraulic auxiliary drive;

P is the pressure of the high-pressure accumulator; P _min is the minimum working pressure of the cold start accumulator; V is the vehicle speed; V1 is the vehicle speed when the motor starts economically; V2 is the vehicle speed when the motor drives the highest economic speed; T is the vehicle demand torque; T1 The maximum torque that the motor can provide.

Further, the mode control logic in which the hydraulic system participates in the work is as follows: braking modes include light braking mode, moderate braking mode, and heavy braking mode,

In mild braking mode, when P<P _max , it is hydraulic regenerative braking; when P>P _max and SOC<0.8, it is motor regenerative braking; when P>P _max and SOC>0.8, it is friction braking;

In moderate braking mode, when P<P _max , if the hydraulic regenerative braking force is greater than the required braking force, it is hydraulic regenerative braking; if the hydraulic regenerative braking force is less than the required power, and SOC>0.8, it is hydraulic braking Friction composite braking, if SOC<0.8, it is electro-hydraulic composite braking;

In moderate braking mode, when P>P _max , when SOC>0.8, it is friction braking; when SOC<0.8, if the regenerative braking force of the motor is greater than the required braking force, it is regenerative braking of the motor, otherwise Friction compound braking for the motor;

In heavy braking mode, it is friction braking;

If it is friction braking, S>0.2, ABS anti-lock braking of electro-hydraulic hybrid power transmission system;

Z is the braking strength; P is the pressure of the high-pressure accumulator; P _max is the maximum working pressure of the high-pressure accumulator; SOC is the state of charge of the battery; S is the slip rate of the wheel.

Owing to adopting above-mentioned technical scheme, the present invention has following advantage:

The invention is applied to the new electro-hydraulic hybrid power transmission system of the car. On the basis of the original pure electric vehicle transmission system, the hydraulic drive system composed of hydraulic pump/motor, high and low pressure accumulator, hydraulic valve parts and hydraulic controller is added. More effective recovery and utilization of braking energy, avoiding the impact of high current charging and discharging on the cycle life of the battery, reducing the electric loss of the motor and reducing the wear of the brake friction plate.

Description of drawings

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with the accompanying drawings, wherein:

Figure 1 is a schematic structural diagram of a complete vehicle scheme in which the coupling mode is torque coupling;

Fig. 2 is the control logic diagram of the hydraulic system participating in the drive mode of the present invention;

Fig. 3 is a logical block diagram of the hydraulic system participating in the braking mode control of the present invention;

Fig. 4 is a schematic structural diagram of a complete vehicle scheme in which the coupling mode is rotational speed coupling.

detailed description

The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings; it should be understood that the preferred embodiments are only for illustrating the present invention, rather than limiting the protection scope of the present invention.

An electro-hydraulic hybrid power transmission system, including an electric drive system and a coupling mechanism 1, and also includes a hydraulic drive system, the hydraulic drive system is connected to the coupling mechanism through a clutch 2, and the coupling mode can be either torque coupling or rotational speed Coupling, the working principle of speed coupling is basically the same as that of torque coupling, except that the clutch is replaced by a brake.

The hydraulic drive system includes a hydraulic pump/motor 4 , a hydraulic pump/motor control circuit, a high pressure accumulator 12 and a low pressure accumulator 14 . The hydraulic pump/motor acts on the main transmission system through the coupling mechanism. The oil flows from the high-pressure accumulator through the hydraulic motor to the low-pressure accumulator, drives the hydraulic motor to rotate and provides power to the transmission system, and is mainly used for vehicle starting, acceleration, and climbing Wait for working conditions. When the vehicle brakes, the hydraulic pump rotates, sending the oil in the low-pressure accumulator to the high-pressure accumulator for storage, recovering the braking energy and generating resistance torque to prevent the vehicle from running. The hydraulic pump/motor can be used as a pump or a motor. When used as a pump, the hydraulic oil is compressed to the high-pressure accumulator 12 for storage. When used as a motor, the high-pressure oil drives the motor to drive the vehicle drive.

The hydraulic pump/motor control loop includes a hydraulic pump/motor operating mode control loop and a hydraulic pump/motor swash plate inclination control loop, the power output end of the hydraulic pump/motor is connected to the clutch, and the output end of the hydraulic pump/motor is The oil ports are respectively connected to the first oil port of the hydraulic pump/motor work mode control circuit and the oil port of the low-pressure accumulator, and the oil inlet port of the hydraulic pump/motor is connected to the second oil port of the hydraulic pump/motor work mode control circuit. The third oil port of the hydraulic pump/motor working mode control circuit is connected with the oil port of the high-pressure accumulator and the oil port of the hydraulic pump/motor swash plate inclination angle control circuit respectively.

The hydraulic pump/motor working mode control circuit includes a first electromagnetic reversing valve 5, a first cartridge valve 10, a second cartridge valve 11 and a third electromagnetic reversing valve 13, and the first electromagnetic reversing valve 5 The oil inlet of the hydraulic pump/motor, the oil inlet of the third electromagnetic reversing valve 13, the side oil port of the second cartridge valve 11, and the oil port of the low-pressure accumulator 14 are respectively connected. The oil outlet of the first electromagnetic reversing valve 5 is respectively connected with the side oil port of the first cartridge valve 10, the bottom oil port of the second cartridge valve 11, and the oil port of the high-pressure accumulator 12 through the check valve. The oil control end of the second cartridge valve 11 is connected to the oil outlet of the third electromagnetic reversing valve 13, the bottom oil port of the first cartridge valve 10 is connected to the oil inlet of the hydraulic pump/motor, and the first cartridge valve 10 is connected to the oil inlet of the hydraulic pump/motor. The oil control end of the valve is connected with the oil outlet of the first electromagnetic reversing valve 5 .

The hydraulic pump/motor swash plate inclination control circuit includes a hydraulic cylinder 3, a pressure reducing valve 9 and a second electromagnetic reversing valve 8, the oil inlet of the pressure reducing valve is connected with the oil port of the high-pressure accumulator, the The oil outlet of the pressure reducing valve is connected to the P port of the second electromagnetic reversing valve, the O port of the second electromagnetic reversing valve is connected to the oil tank, and the A port of the second electromagnetic reversing valve is connected to the inlet port of the hydraulic cylinder. The oil port is connected, and the B port of the second electromagnetic reversing valve is connected with the oil outlet of the hydraulic cylinder, and the piston rod of the hydraulic cylinder is mechanically connected with the swash plate of the hydraulic pump/motor.

In this embodiment, the first electromagnetic reversing valve is a two-position four-way electromagnetic reversing valve, the second electromagnetic valve is a three-position four-way electromagnetic reversing valve, and the third electromagnetic reversing valve is a two-position two-way Solenoid directional valve. The power of the electric drive system is greater than the power of the hydraulic drive system.

The working principle of the present invention is: when the vehicle starts, accelerates, and climbs a slope, the oil in the high-pressure accumulator flows to the low-pressure accumulator through the hydraulic motor, drives the hydraulic motor to rotate, acts on the transmission system through the coupling mechanism, and drives the vehicle drive. When the vehicle is running normally, it is driven by the main motor, and the hydraulic system does not participate in the work. Its control logic block diagram is shown in Figure 2. Among them, P is the pressure of the high-pressure accumulator; P _min is the minimum working pressure of the cold start accumulator; v is the vehicle speed; v1 is the vehicle speed when the motor starts economically; v2 is the vehicle speed when the motor drives the highest economic speed; T is the vehicle demand torque; T1 is the maximum torque that the motor can provide.

When the vehicle brakes, according to the braking intensity, the hydraulic pump is preferentially used to rotate when braking with low intensity, and the oil pressure in the low-pressure accumulator is injected into the high-pressure accumulator to generate a resistance torque at the same time, preventing the vehicle from running, and braking The energy is converted into hydraulic energy and stored in the high-pressure accumulator. When the pressure of the high-pressure accumulator reaches its maximum working pressure, the clutch is disconnected, and the transmission system drives the generator to generate electricity, and the braking energy is converted into electrical energy and stored in the battery. , its control logic block diagram is shown in Figure 3. Among them, Z is the braking intensity; P is the pressure of the high-pressure accumulator; P _max is the maximum working pressure of the high-voltage accumulator; SOC is the state of charge of the battery; s is the wheel slip rate.

Specifically, the working modes of the present invention include:

(1) Cold start. The motor 6 is not started first, the first electromagnetic reversing valve 5 is placed in the right position, the high-pressure accumulator 12 releases high-pressure oil, drives the hydraulic motor 4 to rotate, and the power drives the transmission system through the coupling mechanism 1, thereby making the car start. When the motor starts rotating speed, the motor 6 starts, the clutch 2 is disconnected, the displacement of the hydraulic motor 4 is set to zero, and the first electromagnetic reversing valve 5 is placed in the left position.

(2) Accelerate or climb a hill. When the car accelerates or climbs a slope, in order to better exert the power performance of the car, the solenoid valve 5 is placed in the right position, the oil in the high-pressure accumulator 12 is released, the hydraulic motor 4 is driven to rotate, and the auxiliary motor drives the car to accelerate or climb a slope .

(3) Deceleration braking. When the car decelerates and brakes, the clutch 2 is engaged, and the hydraulic pump 4 rotates, hydraulically pumping the oil in the low-pressure accumulator 14 into the high-pressure accumulator 12, and storing hydraulic energy while generating resistance torque to prevent the vehicle from running, thereby producing a braking effect. When the pressure of the high-pressure accumulator 12 reaches its maximum working pressure, the clutch 2 is disconnected, and the motor 6 is used as a generator to charge the storage battery 7. While generating electricity, a resistance torque is generated to prevent the vehicle from running and produce a braking effect.

(4) Driving liquid filling. When the driving power demanded by the vehicle is not large, the clutch 2 is engaged, and the motor 6 drives the vehicle to drive the hydraulic pump 4 to rotate at the same time, and the oil pressure of the low-pressure accumulator 14 is injected into the high-pressure accumulator 12 to store hydraulic energy, which is convenient for the next time. Used during cold boot.

(5) unloading. The third electromagnetic reversing valve 13 is placed in the left position, the high-pressure accumulator 12 and the low-pressure accumulator 14 are communicated, and the hydraulic circuit is unloaded.

When the car brakes, the hydraulic pump 4 absorbs the kinetic energy of the brake, which can effectively alleviate the wear of the brake friction plate, prolong its service life, and avoid the impact of high current charging on the battery 7 when the brake is just started. When the vehicle starts, the vehicle is driven by hydraulic pressure, which avoids the impact of large current discharge on the battery 7 during the start. Compared with pure electric vehicles, the energy recovery efficiency is higher, and the dynamic response is faster when driving or braking.

In the present invention, the mode control logic in which the hydraulic system participates in the work is as follows:

a) The driving modes that the hydraulic system participates in include cold start mode, driving fluid filling mode, acceleration or climbing mode, and its control logic is shown in Figure 2;

b) The braking mode is divided into mild braking mode (Z<0.1), moderate braking mode (0.1<Z<0.7), and severe braking mode (Z>0.7). Dynamic safety, the hydraulic system does not participate in the work, it is directly completed by the friction system, and its control logic is shown in Figure 3.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies thereof, the present invention also intends to include these modifications and variations.

Claims (7)

1. a kind of electrohydraulic mixed power transmission system, including power-driven system and coupling mechanism（1）, it is characterised in that：Also wrap Fluid power system is included, the fluid power system passes through clutch（2）It is connected with coupling mechanism；The fluid power system bag Include hydraulic pump/motor（4）, hydraulic pump/motor control loop, high pressure accumulator（12）And low pressure accumulator（14）, the hydraulic pressure Pump/motor control loop includes hydraulic pump/motor mode of operation control loop and hydraulic pump/motor swashplate angle control loop, The clutch end of the hydraulic pump/motor is connected with clutch, the oil-out of the hydraulic pump/motor respectively with hydraulic pump/ The hydraulic fluid port connection of the first hydraulic fluid port of motor operations mode control loop, low pressure accumulator, the oil inlet of the hydraulic pump/motor with The second hydraulic fluid port connection of hydraulic pump/motor mode of operation control loop, the of the hydraulic pump/motor mode of operation control loop Three hydraulic fluid ports hydraulic fluid port respectively with high pressure accumulator, the hydraulic fluid port of hydraulic pump/motor swashplate angle control loop are connected；The hydraulic pressure Pump/motor mode of operation control loop includes the first solenoid directional control valve（5）, the first inserted valve（10）, the second inserted valve（11）With 3rd solenoid directional control valve（13）, first solenoid directional control valve（5）Oil inlet oil discharge outlet, respectively with hydraulic pump/motor Three solenoid directional control valves（13）Oil inlet, the second inserted valve（11）Side hydraulic fluid port, low pressure accumulator（14）Hydraulic fluid port connection, it is described First solenoid directional control valve（5）Oil-out by check valve respectively with the first inserted valve（10）Side hydraulic fluid port, the second inserted valve （11）Bottom hydraulic fluid port, high pressure accumulator（12）Hydraulic fluid port connection, second inserted valve（11）Oil-control end and the 3rd electromagnetism Reversal valve（13）Oil-out connection, first inserted valve（10）Bottom hydraulic fluid port be connected with the oil inlet of hydraulic pump/motor, First inserted valve（10）Oil-control end and the first solenoid directional control valve（5）Oil-out connection.

2. electrohydraulic mixed power transmission system according to claim 1, it is characterised in that：The hydraulic pump/motor swash plate Pitch angle control loop includes hydraulic cylinder（3）, pressure-reducing valve（9）With the second solenoid directional control valve（8）, oil inlet and the height of the pressure-reducing valve The hydraulic fluid port connection of accumulator is pressed, the oil-out of the pressure-reducing valve is connected with P mouthfuls of the second solenoid directional control valve, and second electromagnetism is changed Fuel tank is connected to O mouthfuls of valve, A mouthfuls of second solenoid directional control valve is connected with the oil inlet of hydraulic cylinder, the second electromagnetic switch B mouthfuls of valve is connected with the oil-out of hydraulic cylinder, and the piston rod of the hydraulic cylinder is mechanically connected with the swash plate of hydraulic pump/motor.

3. electrohydraulic mixed power transmission system according to claim 1 and 2, it is characterised in that：The power-driven system Power more than fluid power system power.

4. electrohydraulic mixed power transmission system according to claim 1, it is characterised in that：The coupling mechanism is torque coupling Close or rotating speed coupling.

5. electrohydraulic mixed power transmission system according to claim 3, it is characterised in that：The mould of hydraulic system participation work Formula is as follows：

Ⅰ）Cold start-up, motor（6）Do not start first, the first solenoid directional control valve（5）It is placed in right position, high pressure accumulator（12）Release high pressure Fluid, drives hydraulic pump/motor（4）Rotate, then by coupling mechanism（1）Transmission system is driven, and then causes vehicle starting, When electric motor starting rotating speed is reached, motor（6）Start, clutch（2）Disconnect, hydraulic pump/motor（4）Discharge capacity is set to zero, first Solenoid directional control valve（5）It is placed in left position；

Ⅱ）Accelerate or climbing traveling, when acceleration or climbing, in order to preferably play automobile dynamic quality, by the first electricity Magnetic reversal valve（5）Right position is placed in, high pressure accumulator is discharged（12）Fluid, drives hydraulic pump/motor（4）Rotate, stand-by motor drives Electrical automobile accelerates or climbs；

Ⅲ）Retarding braking, when car deceleration is braked, clutch（2）Engagement, hydraulic pump/motor（4）Rotation, by low pressure accumulation of energy Device（14）In fluid press-in high pressure accumulator（12）, produce the moment of resistance to prevent vehicle traveling while storage hydraulic energy, produce Braking effect；Work as high pressure accumulator（12）When pressure reaches its maximum working pressure, clutch（2）Disconnect, motor（6）Work as generating Machine is used, and is battery（7）Charge, produce the moment of resistance to prevent vehicle traveling while generating, produce braking effect；

Ⅳ）Driving topping up, when vehicle requirement drive power is little, clutch（2）Engagement, by motor（6）Drive vehicle traveling While drive hydraulic pump/motor（4）Rotation, by low pressure accumulator（14）Fluid press-in high pressure accumulator（12）, store liquid Pressure energy, uses during convenient cold start-up next time；

Ⅴ）Off-load, by the 3rd solenoid directional control valve（13）It is placed in left position, high pressure accumulator（12）, low pressure accumulator（14）Communicate, liquid Push back road off-load.

6. electrohydraulic mixed power transmission system according to claim 5, it is characterised in that：The mould of hydraulic system participation work Formula control logic is as follows：

a）The drive pattern that hydraulic system is participated in includes cold start mode, normally travel, acceleration or climbing pattern, and its control is patrolled Collecting includes：

In the cold start mode, P is worked as<P_minWhen, it is electric motor starting；Work as P>P_minWhen, it is hydraulic starting；When for hydraulic starting, When vehicle velocity V is more than or equal to V1, electric motor starting is transformed to；

In a normal traveling mode, P is worked as<P_minWhen, it is driving topping up；Work as P>P_minWhen, it is that motor drives；

Under acceleration or climbing pattern, work as P<P_minWhen, it is that motor drives；Work as P>P_minWhen, and V is big more than or equal to V2 or T It is hydraulic pressure process auxiliary drive when equal to T1；

P is high pressure accumulator pressure；P_minIt is cold starting accumulator minimum operating pressure；V is car speed；V1 is motor economy Speed during startup；V2 motors drive speed during highest economic speed；T automobile demand moments of torsion；T1 can be provided for motor Peak torque.

7. electrohydraulic mixed power transmission system according to claim 6, it is characterised in that：The mould of hydraulic system participation work Formula control logic is as follows：Braking mode includes light brake pattern, moderate braking mode, severe braking mode,

Under light brake pattern, work as P<P_maxWhen, it is hydraulic regenerative braking；Work as P>P_maxAnd SOC<It is motor regeneration system when 0.8 It is dynamic；Work as P>P_maxAnd SOC>It is friction catch when 0.8；

Under moderate braking mode, work as P<P_maxWhen, it is hydraulic regenerating system if hydraulic regenerative braking power is more than demand brake force It is dynamic；If hydraulic regenerative braking power is less than demand motive force, and SOC>It is hydraulic frictional composite braking, if SOC when 0.8<0.8, then It is Electro-hydraulic brake；

Under moderate braking mode, work as P>P_maxWhen, work as SOC>It is friction catch when 0.8；Work as SOC<When 0.8, if motor regenerates It is motor regenerative braking when brake force is more than demand brake force, is otherwise motor friction composite braking；

It is friction catch under severe braking mode；

If during friction catch, S>0.2, the ABS ANTI LOCKs of electrohydraulic mixed power transmission system；

Z is severity of braking；P is high pressure accumulator pressure；P_maxHigh pressure accumulator maximum working pressure；SOC is the charged shape of battery State；S is wheel slip.