CN205330816U

CN205330816U - High pressure common rail fuel injection pressure control system

Info

Publication number: CN205330816U
Application number: CN201521088950.0U
Authority: CN
Inventors: 伍茜; 陈卫; 王玉
Original assignee: Special Filtering Technique Ltd Co Of Suzhou Tamiflu
Current assignee: Special Filtering Technique Ltd Co Of Suzhou Tamiflu
Priority date: 2015-12-24
Filing date: 2015-12-24
Publication date: 2016-06-22
Anticipated expiration: 2025-12-24

Abstract

The utility model discloses a high pressure common rail fuel injection pressure control system to direct current motor driven electric fuel delivery pump is execute component, and carry out high pressure common rail fuel injection pressure through regulation low voltage output oil mass and adjust, its characterized in that, through the goal driven PWM signal value of gathering thruster operation parameter calculation fuel injection pressure setting value and electric fuel delivery pump, PWM signal dutyfactor's control logic changes along with the switching of thruster operation operating mode mode. The utility model discloses control electric fuel delivery pump's fuel delivery carries out common rail spraying pressure to be adjusted, avoids the load of engine unnecessary, improves the energy conversion efficiency of engine, agree with the car executor the intellectuality, integrate, the modular development trend. This has changed the traditional control of common rail fuel injection pressure, demarcation mode, has reduced the technological dependence to the high pressure common rail oil spout supplier of system, helps improving autonomic design, the development ability of engine and diesel vehicle manufacturer.

Description

A kind of high-pressure common rail oil injection control pressurer system

Technical field

This utility model relates to high-pressure common rail oil injection Stress control, particularly relates to one by regulating low pressure fuel system fuel delivery and realizes the pressure controlled method and system of high-pressure common rail oil injection。

Background technology

Electronic control system is high with its injection pressure, and injection pressure can be adjusted independent of engine speed, it may be achieved flexible accurately controlling of oil spout and become the mainstream technology of diesel vehicle energy-saving and emission-reduction。High pressure co-rail system implements the control of oil rail pressure power and injection pressure by regulating oil-feed flow velocity in high pressure oil rail, and executor is flow control valve and ECU。Oil transfer pump is responsible for transmitting oil mass to maintain the injection pressure and distributive value etc. set to high tension loop, and the drive pattern of oil transfer pump has Mechanical Driven and a motor driving two kinds, general in engineering partially uses the former。Perfected electromagnetic metering valve is responsible for the flow of common rail system demand is supplied to high-pressure oil pump, and its installation site is positioned at the rear end of oil transfer pump。

Consideration for universal design, the engine performance span that a high pressure common rail fuel injection system can mate is big, and the pumping ability of its oil transfer pump is not mate according to the actual demand of electromotor: distributive value+common rail system hydraulic control flow+oil transfer pump cooling, lubrication flow。When oil transfer pump transmits oil mass more than common rail system demand, oil mass more than needed pumps repeatedly by returning to oil transfer pump oil-feed channel after oil return valve。After this oil transfer pump, the mode of fuel-flow control causes unnecessary oil mass repeatedly to be pumped, and operating temperature increases, and oil pumping system efficiency is low, and the unnecessary load of Diesel engine increases。Domestic also have the system using electrically operated fuel pump, in these systems, electrodynamic pump oil transportation amount is not regulated, the same with mechanical oil transfer pump carries out passive oil amount adjustment after pump。This causes the fuel delivery when engine low load suitable with high load capacity fuel delivery, and recirculating oil quantity is higher, and pump oil efficiency is even low than mechanical oil transfer pump system。

As shown in Figure 1, the fuel delivery of mechanical oil transfer pump covers the demand oil mass of common rail system to traditional electronic control system rail pressure control fuel circuit incessantly, is also responsible for the lubrication oil mass of oil transfer pump。Because the supply capability of mechanical oil transfer pump is limited mainly by driving influence of rotation speed, it is impossible to carrying out flow adjustment according to system requirements, cause the idle work of mechanical pump oil, this is at electromotor height rotating speed, and underrun region shows particularly evident。

Utility model content

This utility model purpose is: provides a kind of and realizes the pressure controlled method and system of high-pressure common rail oil injection by regulating low pressure fuel system fuel delivery, accurately regulates realizing common rail system injection pressure, improves the fuel economy of high pressure co-rail system, reduce CO₂Discharge。

The technical solution of the utility model is:

A kind of high-pressure common rail oil injection compress control method, with the electrically operated fuel pump of DC motor Driver for executive component, high-pressure common rail oil injection pressure adjustment is carried out by regulating low pressure output oil mass, calculate the target drives pwm signal value of injection pressure setting value and electrically operated fuel pump by gathering engine operating parameter, the control logic of pwm signal dutycycle changes with the switching of engine operation condition pattern；The operating condition pattern of electromotor includes following 7 classes: state of starting operating, in shelves coasting mode, idling start-stop operating mode, engine work operating mode, emission aftertreatment regeneration regime, diagnostic mode operating mode and racing of the engine operating mode；Under different operating modes, the setting value of co-rail oil injection pressure is different, control model includes the combination control model that open loop feedforward control, the feedforward and closed loop feedback control jointly to carry out, the feedforward is responsible for quickly regulating the fuel supply flow rate of oil transfer pump when transient condition, the co-rail oil injection pressure real-time followability to setting injection pressure that closed loop feedback controls to be responsible under disturbance operating mode by a small margin is concrete:

1.1) open loop feedforward control method includes:

ECU is looked into 3 dimension tables obtain feedforward flow Rail_dvolPreCtl according to engine speed, load signal, and described 3 dimension tables need to pass through specialty and demarcate flow process generation；

1.2) feedforward+closed-loop feedback control method includes:

A. ECU is looked into the rail pressure feedforward 3 dimension table obtain feedforward flow Rail_dvolPreCtl according to engine speed, load signal；

B. ECU is looked into injection pressure according to engine speed, load signal and is set 3 dimension tables and obtain target control rail pressure Rail_pSetPointBas, according to engine operating temperature, goal pressure is modified by atmosphere pressure signal, then entered data reasonableness check qualified after obtain target control rail pressure Rail_pSetPoint；

C. closed loop controller uses PID controller, the input parameter rail pressure deviation value rail_pGov of PID controller, and concrete meaning is the difference of the target rail pressure Rail_pSetPoint real-time pressure RailCD_pPeak gathered with common rail pressure sensor；

The parameter reference Ziegler-Nichols Tuning of d.PID controller carries out and writes in memorizer；Controller looks into, according to engine speed, load, control parameter Kp, Ki, the Kd that 2 dimension tables of each controlling unit of PID controller obtain under this operating mode, by discrete mathematics formula:

It is controlled the demand volume real-time update of device；

1.3) computational methods of ECU control flow include:

It is that open loop feedforward control flow Psp_dvolPreCtl or open loop feedforward control flow Psp_dvolPreCtl and PID controls flow Psp__dvolCtl sum that ECU controls flow, and control unit is controlled the selection of pattern in conjunction with engine operation condition pattern；Control unit obtains the equivalent operation electric current Psp_iDes of electrically operated fuel pump according to the 3 dimension table Psp_iPspCnvflow_Map controlling flow and oil temperature sensor signal lookup electrically operated fuel pump operating characteristic；PWM regulates model and current value converts to PWM duty cycle control signal automatically；Duty cycle range restriction is carried out by maximum allowable PWM duty cycle value Psp_dcycMax_C and minimum permission PWM duty cycle value Psp_dcycMin_C。

Preferably, in normal operation, when high pressure oil rail pressure and setting value deviation are excessive or its absolute value exceedes the upper limit, ECU carries out the Fault Control pattern of rail pressure according to engine rotational speed signal and load signal, the power output of restriction electromotor, stops fuel injector oil spout under emergency situation。

Preferably, described ECU changes the running voltage of executive component by regulating pulse width dutycycle, it is achieved the oil transportation amount to low pressure fuel system。

A kind of control system of the high-pressure common rail oil injection pressure adopting control method described above, including, common rail pressure sensor, ECU, power driver module, electrically operated fuel pump, two CAN communication modules and dual serial interface circuit, wherein,

Common rail pressure sensor, gathers the pressure signal in common rail and is sent to ECU by the first CAN communication module；

First CAN communication module is responsible for carrying out information transmission between microprocessor and control unit of engine, and transport packet draws together engine operation condition, fault mode, engine speed, engine load signal, common rail pressure transducing signal；Second CAN communication module is used for ECU data scaling；

ECU, runs actual condition according to electromotor and common rail pressure transducing signal carries out electrically operated fuel pump flow by power driver module and regulates in real time；

Power driver module, is responsible for the pulsewidth modulation of PWM and drives signal output, and its output is connected with the power input of electrically operated fuel pump；

Described electrically operated fuel pump, by DC motor Driver, carries out high-pressure common rail oil injection pressure adjustment by regulating low pressure output oil mass；

Dual serial interface circuit, is all connected with ECU, the first serial interface circuit universal serial port circuit, monitors for universal serial port, and the second serial interface circuit is the circuit for KWP2000 communication protocol, for fault diagnosis communication。

Preferably, described power driver module adopts semibridge system power driver module。

Preferably, the direct current generator of described electrically operated fuel pump is connected to current controller, it is prevented that the existence of variations in temperature and solenoid winding inductance causes real work curent change。

Preferably, the direct current generator of described electrically operated fuel pump is also associated with PWM and drives operating frequency actuator, it is prevented that during work, power consumption is excessive causes that ECU feeds。

The utility model has the advantages that:

This utility model controls the fuel delivery of electrically operated fuel pump and carries out common rail injection pressure adjustment, it is to avoid the load that electromotor is unnecessary, improves the energy conversion efficiency of electromotor, agrees with the intellectuality of automobile executor, development trend integrated, modular。This changes traditional co-rail oil injection Stress control, calibration mode, and the technology to high-pressure common-rail injection system supplier that reduces relies on, and is favorably improved electromotor and the autonomous Design of diesel vehicle manufacturer, development ability。In global design, carry out EMC Design according to country's Electro Magnetic Compatibility Experimental Standardization。Adopt international standards between system and calibration software agreement, the Real time displaying of data can be conveniently realized, demarcate amendment。

This utility model compared with prior art, has the following advantages and beneficial effect: 1, the pressure controlled impact of common rail injection is difficult to embody by low pressure fuel system in traditional rail pressure control pattern, and this utility model overcomes the deficiency of this respect；2, by electrically operated fuel pump fuel delivery, the fuel economy of electromotor also there is certain improvement；3, being no longer necessary in high pressure fuel injection electromagnetic measurement unit and oil return valve, the parts of whole fuel transfer system reduce, and contribute to reducing development cost。

Accompanying drawing explanation

Below in conjunction with drawings and Examples, this utility model is further described:

Fig. 1 is that existing Electrocontrolled high-pressure common rail injection pressure controls fuel circuit schematic diagram；

Fig. 2 is this utility model is that described Electrocontrolled high-pressure common rail injection pressure controls fuel circuit schematic diagram；

Fig. 3 is this utility model is the hardware connection figure of described high-pressure common rail oil injection control pressurer system；

Fig. 4 is this utility model is described pressure control of common rail system logic diagram；

Fig. 5 is this utility model is described injection pressure setting value logic chart；

Fig. 6 is this utility model is that described PID closed loop injection pressure controls logic chart；

Fig. 7 is this utility model is described electrically operated fuel pump PWM pulse-width controlled adjustment block-diagram；

Fig. 8 is this utility model is described oil transfer pump power driver module；

Fig. 9 is this utility model is described electrically operated fuel pump automatically cleaning logic control chart。

Detailed description of the invention

Below with reference to detailed description of the invention shown in the drawings, this utility model is described in detail。But these embodiments are not limiting as this utility model, those of ordinary skill in the art is all contained in protection domain of the present utility model according to the made structure of these embodiments, method or conversion functionally。

As in figure 2 it is shown, be that Electrocontrolled high-pressure common rail injection pressure described in the utility model controls fuel circuit schematic diagram, the fuel delivery of oil transfer pump is just equal to the demand volume of common rail system。This utility model controls the fuel delivery of electrically operated fuel pump and carries out common rail injection pressure adjustment, it is to avoid the load that electromotor is unnecessary, improves the energy conversion efficiency of electromotor, agrees with the intellectuality of automobile executor, development trend integrated, modular。This changes traditional co-rail oil injection Stress control, calibration mode, and the technology to high-pressure common-rail injection system supplier that reduces relies on, and is favorably improved electromotor and the autonomous Design of diesel vehicle manufacturer, development ability。

The utility model discloses a kind of new Electrocontrolled high-pressure common rail injection pressure control method and system。Electrocontrolled high-pressure common rail injection pressure controls the connection of system core electromechanical component, communication modes as shown in Figure 3, with the electrically operated fuel pump of DC motor Driver for executive component, and the sensing element being controlling unit with common rail pressure sensor；Control unit carries out electrically operated fuel pump flow according to electromotor operation actual condition and regulates in real time, thus ensureing that injection pressure reaches target setting, lays a solid foundation for bavin oil injection, atomization, burning。

This utility model develops working condition running state machine, and the operating condition of refinement electromotor defines the toggle path of each operating mode simultaneously。The operating condition of Diesel engine, except normal driving operating mode, also includes: state of starting operating, in shelves coasting mode, idling start-stop operating mode, emission aftertreatment regeneration regime, diagnostic mode operating mode, racing of the engine operating mode etc.。In engine ignition key power-off, but the situation that ECU supply relay keeps adhesive is in industry commonly referred to as afterrun。The setting value of co-rail oil injection pressure and to control logic different under different regime mode。

The logic diagram of co-rail oil injection pressure setting is as shown in Figure 4, it is necessary first to carry out the operating mode's switch of electromotor, determines therefrom that the setting of injection pressure desired value。Such as diagnostic test need to carry out Hi-pot test, and engine load is little but expulsion pressure is big；In shelves sliding mode, rail pressure setting value is discrete jump value, covers the gamut of injection pressure variation with limited operating point；Under emission aftertreatment regeneration mode on the low side to improve engine exhaust temperature under rail pressure setting value compared with normal pattern。Once detect that hypervelocity occurs in electromotor, electrically operated fuel pump should stop pump oil immediately。During idling start-stop, although engine speed is zero, but when needing to maintain certain pressure (diesel oil) for green light in high pressure oil rail, electromotor quickly starts and prepares。

Identifying engine electric-controlled system operation exception once fault diagnosis system and can enter degradation protected mode, injection pressure setting value uses substitution value。The setting value of injection pressure also needs to the correction of temperature and the atmospheric pressure considering system work, and the fuel oil to ensure the best sprays thus realizing the fuel oil of the best, air mixed combustion。Once rail pressure setting value exceedes in the range of safety operation of common rail system, mechanical engine members fault can be caused, cause huge loss。This utility model carries out the reasonableness check of rail pressure setting value, after all going well, in the 3 dimension data tables ability write control unit memorizeies that injection pressure sets。

Native system carries out the adjustment of pressure in high pressure oil rail by regulating the pump oil mass of oil transfer pump, and the demand volume of common rail system can be divided into: 1, participate in the distributive value of work by combustion；2, hydraulic buttery valve fuel injector control flow and reveal flow。3, the flow of the certain expulsion pressure of common rail intracavity is maintained；4, the lubrication of mechanical oil transfer pump, cooling flow etc.。When engine stabilizer runs, rotating speed is certain, and load is certain, and the demand volume of common rail system is obtained by specific testing process, has carried out the application of the feedforward based on this this utility model。During electromotor actual motion, rotating speed, load are in real-time change, and injection pressure setting value is no exception, the proper use of real-time followability that can ensure that rail pressure of PID closed loop controller。Common rail injection pressure control logic of the present utility model as shown in Figure 5, is divided into the feedforward and closed loop control, and control unit is looked into 3 dimension data tables and obtained feedforward control amount and quickly eliminate static deviation, and PID controller is responsible for the small size adjustment of small size deviation。Usually when the feedforward and PID closed loop control work simultaneously, feedforward flow need to reach PID and control more than 2 times of flow。

The closed loop PID logic of injection pressure controls figure as shown in Figure 6, ratio, integral element input be injection pressure setting value with measured value inclined difference DELTA P。Proportional coefficient K p is different with rotation speed change, and it is Kp* Δ P that proportional component regulates flow；Integral coefficient Ki coefficient is with rotation speed change, and it is Ki* Δ P that integral element regulates flow。The focus of integral element is that rail pressure deviation is added up, and unconfined persistently adding up can cause that counter O reset resets。This utility model has carried out the anti-of proportional component and has reset design, and after proportional component output flow reaches setting upper limit value and lower limit value, integral element output stream value is frozen, it is prevented that the output of integral element resets the rail pressure fluctuation caused。The rate of change of rail pressure deviation is predicted regulating by differentiation element, efficiently controls rail pressure overshoot。But differentiation element is sensitive to interference noise, making system suppress the ability of interference to reduce, therefore the input of differentiation element is through pretreatment such as digital filters。

Control unit designed by this utility model realizes the rotating speed of actuating motor is controlled by regulating the output voltage of half-bridge driven chip, actuating motor resistance is with temperature change, cause that real work electric current there are differences, real electrical machinery rotating speed and setting value do not correspond, devising current controller for this this utility model, its work-based logic figure is as shown in Figure 7。Psp_iAct is surveyed by current measurement circuit, and current deviation value Psp_iDvt is as the input of current controller, and Psp_iDvtCor is the output of current controller, directly changes the setting value of dutycycle。For the operating current of change, the inductive obstacle of the motor coil winding real-time followability of electric current, this utility model can effectively remove the impact of inductance by one order inertia digital filter。

The driving circuit principle figure of electrically operated fuel pump refers to accompanying drawing 8: this utility model uses half-H-bridge drive pattern, drive motor one-directional rotation。PMOS turns on when grid is low level, closes during high level；NMOS tube turns on when grid is high level, closes during low level。IN be automatically controlled input signal to control pmos pass section, when IN input low level, PMOS turn on, N pipe disconnect, the voltage that MOS motor driven voltage provides for battery component, during IN input high level, PMOS disconnection, motor driven voltage is 0。IN is PWM and inputs signal, thus the PWM realizing motor driven voltage controls。

The existence of the impurity such as solid particulate matter can cause oil transfer pump work dischargeable capacity to diminish, oil transfer pump hydraulic performance decline；Control unit, once to recognize rail pressure on the low side, can regulate PWM duty cycle control signal to improve motor working current to strengthen pump oil mass。For protection motor component, this utility model devises electrically operated fuel pump self-cleaning function, as it is shown in figure 9, be electrically operated fuel pump automatically cleaning logic control chart, and this function activation when electromotor is in Afterrun operating mode。Its basic functional principle is: driving at a certain time interval, close motor, washed away by the flow of alternation, coordinate the oil transfer pump oil groove of unique design, particulate matter is rushed out oil transportation pump chamber。

Above-described embodiment only for technology of the present utility model design and feature are described, its object is to allow person skilled in the art will appreciate that content of the present utility model and to implement according to this, can not limit protection domain of the present utility model with this。All modifications done according to the spirit of this utility model main technical schemes, all should be encompassed within protection domain of the present utility model。

Claims

1. the control system of a high-pressure common rail oil injection pressure, it is characterised in that include, common rail pressure sensor, ECU, power driver module, electrically operated fuel pump, two CAN communication modules and dual serial interface circuit, wherein,

2. the control system of high-pressure common rail oil injection pressure according to claim 1, it is characterised in that: described power driver module adopts semibridge system power driver module。

3. the control system of high-pressure common rail oil injection pressure according to claim 2, it is characterised in that: the direct current generator of described electrically operated fuel pump is connected to current controller, it is prevented that the existence of variations in temperature and solenoid winding inductance causes real work curent change。

4. the control system of high-pressure common rail oil injection pressure according to claim 3, it is characterised in that the direct current generator of described electrically operated fuel pump is also associated with PWM and drives operating frequency actuator, it is prevented that during work, power consumption is excessive causes that ECU feeds。