[0034] Embodiment 1: The control system and method include a hydraulic hybrid vehicle control method and a hydraulic hybrid vehicle torque control system;
[0035] Control methods for hydraulic hybrid vehicles:
[0036] (1) According to the driver's operation behavior on the accelerator pedal, combined with the vehicle speed in the current state, determine the vehicle drive target torque of the vehicle in the current state, the estimation of the torque of the hydraulic hybrid power system in the current state, and the target torque of the hybrid power system Determination of output torque, engine target output torque command and hydraulic pump motor target output torque command;
[0037] The method for realizing the vehicle driving target torque is: according to the opening degree of the accelerator pedal and the pedal change rate, it is converted into the target driving torque of the vehicle at different speeds and different gears;
[0038] The method for estimating the torque of the hydraulic hybrid power system in the current state is: according to the current speed of the hydraulic pump motor, the working pressure of the hydraulic accumulator, and the efficiency curve of the hydraulic pump motor, calculate the torque of the hydraulic pump motor corresponding to the current speed Maximum drive torque;
[0039] The method for determining the target output torque of the hybrid power system is: converting the driver's demand torque into the target torque of the hybrid power system in the current state, and finding the engine operating efficiency corresponding to the engine universal characteristic curve in the current state. The torque range of UT is compared with the target torque value of the hybrid system, and the target torque of the hydraulic pump motor is determined with reference to the pressure of the hydraulic accumulator. The target torque of the engine is the target torque value of the vehicle and the hydraulic pump motor The difference between the target torque values;
[0040] The specific method of the said engine target output torque instruction is: the data of the engine output torque changing with the throttle opening and the rotating speed in the universal characteristic data of the engine can be sorted into the data of the engine throttle opening changing with the output torque and the rotating speed data sheet. According to the target torque and speed of the engine in the current state, check the data table of the engine throttle opening with the output torque and speed change, and obtain the target value of the engine target throttle opening. According to the target torque of the hydraulic pump motor in the current state, The displacement value of the hydraulic pump motor obtained from the speed, the working pressure of the hydraulic accumulator and the working efficiency curve of the hydraulic pump motor is the corresponding instruction;
[0041] The specific method of the target output torque command of the hydraulic pump motor is: according to the target torque of the hydraulic pump motor in the current state, the rotating speed, the working pressure of the hydraulic accumulator and the working efficiency curve of the hydraulic pump motor to obtain the output torque of the hydraulic pump motor The displacement value is the corresponding instruction;
[0042] (2) According to the current vehicle speed signal, accelerator pedal opening signal, transmission gear position signal, clutch engagement state signal, engine speed signal, hydraulic accumulator pressure signal, and hydraulic pump motor speed signal collected by the sensor, determine the current vehicle speed signal. The operating mode that the hybrid power system should be in under the vehicle state; the operating modes of the hydraulic hybrid power system include: ①Stop mode, ②Hydraulic drive mode, ③Idling mode, ④Drive charging mode, ⑤Engine drive mode, ⑥Braking mode;
[0043] (3) According to the hydraulic pump motor speed signal and hydraulic accumulator pressure signal collected by the sensor, combined with the hydraulic pump motor efficiency curve, find out the corresponding maximum driving torque of the hydraulic pump motor at the current speed;
[0044] (4) Convert the driver's demand torque into the target torque of the hybrid power system in the current state, find the torque range when the engine operating efficiency is better corresponding to the engine universal characteristic curve in the current state, and compare it with the hybrid power system Compared with the target torque value, refer to the pressure of the hydraulic accumulator to determine the target torque of the two power source engines and the hydraulic pump motor in the current state; the details are as follows:
[0045] ① When starting, the SOC of the hydraulic accumulator is ≥ 0.5, the hydraulic accumulator and the hydraulic pump motor provide all the target torque, and the engine does not work;
[0046] ② When starting, the hydraulic accumulator SOC<0.5, the hydraulic pump motor and the engine jointly provide the driving torque; the hydraulic hybrid system provides the maximum driving torque, and the difference between the target torque value and the hydraulic pump motor target torque value is The target torque value of the engine;
[0047] ③During normal driving, the target torque is in the region of high fuel economy (T FL r FH ), the hydraulic hybrid power system does not work, and the engine alone drives the vehicle; the target torque is less than the minimum threshold of the high fuel economy area (T L r FL ), the hydraulic pump motor works in the pump condition, adjusts the engine load, and makes the engine work in the high fuel economy area; the hydraulic pump motor operates at the target torque T p/m ●0.3pV p/m Recover the excess energy of the engine; the target torque is less than the engine start threshold (T L r ), the hydraulic pump motor takes the target torque T p/m ●0.6pV p/m Adjust the load of the engine to ensure that the engine works in the high fuel economy area, and at the same time recover the excess energy of the engine; the target torque is greater than the maximum threshold of the high fuel economy area (T rT FL ), the hydraulic pump motor and the engine jointly provide the driving torque; the hydraulic hybrid system provides the maximum driving torque, and the difference between the target torque value and the hydraulic pump motor target torque value is the target torque value of the engine;
[0048] (5) According to the engine target output torque that step (4) obtains, obtain the engine target throttle opening target value command; According to the target output torque command of the hydraulic pump motor that step (4) obtains; Target torque and speed Check the engine throttle opening with the output torque and speed change data table, get the engine target throttle opening target value, according to the current state of the hydraulic pump motor target torque, speed, hydraulic accumulator The displacement value of the hydraulic pump motor obtained from the working pressure of the hydraulic pump motor and the working efficiency curve of the hydraulic pump motor is the corresponding instruction.
[0049] The hydraulic hybrid vehicle torque control system includes the following three-layer modules: management layer module, control layer module and execution layer module;
[0050] The management module described above is the basis of the entire control system. By collecting the driver's operation signal to the accelerator pedal or brake pedal, the operation behavior of the driving intention is reflected, and combined with the vehicle speed in the current state, it is calculated to determine the current state. The driving torque that the driver hopes to get on the wheels is used as the basis and target of the distribution management of the entire control system;
[0051] The control layer module reasonably distributes the power of the engine and the hydraulic pump motor according to the operating conditions allowed by the system, and sends control commands to the controllers of each component through the transmission interface between the control layer and the execution layer; the control layer includes mode Judgment and capacity estimation sub-module, mainly completes the judgment of hybrid power system operation mode and the estimation of related component assembly capacity;
[0052] The controllers of each component in the execution layer module independently control the respective controlled objects according to the target instruction of the control layer, and feed back the state variables of each component to the control layer;
[0053] The mode determination and capability estimation module in the control layer includes the following submodules: a mode determination submodule, which is used to determine the operating mode of the hydraulic hybrid power system in the current vehicle state; a hydraulic hybrid power system torque estimation submodule, It is used to estimate the torque limit that the hydraulic hybrid power system can provide in the current state; the torque distribution sub-module of the hybrid power system is used to determine the target output torque of the engine and hydraulic pump motor in each mode of the hybrid power system;
[0054] The input terminal of the mode determination sub-module in the control layer is connected to the current vehicle speed signal, the pedal opening signal, the hydraulic accumulator pressure signal, the transmission gear signal, the clutch engagement state signal, the engine speed signal, and the hydraulic pump motor speed signal. The output terminal of the signal; the mode determination sub-module determines the operation mode that the hybrid power system should be in under the current vehicle state according to the current said signal;
[0055] The input terminal of the torque estimation submodule of the hydraulic hybrid system is connected to the output terminal of the hydraulic accumulator pressure signal and the hydraulic pump motor speed signal;
[0056] The input terminal of the hybrid system torque distribution submodule is connected to the output terminal of the hybrid system mode determination submodule and the hydraulic hybrid system torque estimation submodule; it is used to determine the engine and hydraulic pump motor in each mode of the hybrid system. target output torque;
[0057] The execution layer module includes the following submodules: the engine execution instruction submodule is used to control the throttle opening of the gasoline engine; the hydraulic pump motor displacement execution instruction submodule is used to control the swash plate inclination angle of the hydraulic pump motor so that it reaches The target displacement; the hydraulic accumulator control sub-module is used to control the opening and closing of the hydraulic accumulator oil circuit; the clutch control sub-module is used to control the coupling and separation of the clutch.
[0058] The management module, control module and execution module of the torque control system constitute a controller, and the output ports of the controller are respectively connected to the operating parameter display, engine throttle controller, clutch controller and pump/motor control; the input ports of the controller are respectively Connect the accelerator pedal signal, brake pedal signal, clutch status signal, transmission gear signal, engine speed signal, throttle position signal, vehicle speed signal, accumulator pressure signal, pump motor speed signal and pump motor displacement signal.
[0059] In the system of the present invention, the management module is the basis of the entire control system, and the driver is affected by external factors (traffic lights, road obstacles, road gradients and other vehicles) and his own situation (predictability, experience and judgment), the driver It will constantly adjust its own driving behavior (changing the steering angle, the position of the accelerator pedal or brake pedal, shifting gears, etc.). Under the circumstances, the driving torque that the driver hopes to obtain on the wheels is used as the basis and target for the distribution and management of the entire control system.
[0060] The main task of the control layer module is to reasonably allocate the power of the engine and hydraulic pump motor according to the operating conditions allowed by the system, and send control commands to the controllers of each component through the transmission interface between the control layer and the execution layer. The control layer includes mode judgment and capacity estimation modules, which mainly complete the judgment of hybrid power system operation mode and the estimation of related component assembly capacity.
[0061] The mode determination sub-module determines the current vehicle status based on the current vehicle speed signal, accelerator pedal opening signal, hydraulic accumulator pressure signal, transmission gear position signal, clutch engagement state signal, engine speed signal, and hydraulic pump motor speed signal The operating mode the lower hybrid system should be in. The operation mode of the hybrid power system is divided into 6 modes: ①stop mode, ②hydraulic drive mode, ③idle speed mode, ④travel charging mode, ⑤engine drive mode, ⑥brake mode.
[0062]The hydraulic regeneration system torque estimation sub-module receives the pressure signal of the hydraulic accumulator, the speed signal of the hydraulic pump motor and the working efficiency curve of the hydraulic pump motor, and estimates the maximum torque of the hydraulic pump motor under the current state. These torque limits are the upper limit of the drive and recovery capabilities of the hydraulic pump motor under current conditions. Then determine the target output torque of the two power source engines and the hydraulic pump motor in each mode of the hybrid system.
[0063] The controllers of each component in the execution layer module independently control their respective controlled objects according to the control commands of the coordination layer, and feed back the state variables of each component to the coordination layer. This module mainly outputs the gasoline engine target throttle opening command, the hydraulic pump motor current target torque command, and the pump motor operating mode and other commands. The control instructions output by the module can output corresponding control instructions to control the corresponding actuators according to the needs of actual control.
