柴油機(jī)噴油器設(shè)計(jì)【9張圖紙】

柴油機(jī)噴油器設(shè)計(jì)【9張圖紙】,9張圖紙,柴油機(jī),噴油器,設(shè)計(jì),圖紙 Electronic Unit Pump Diesel Engine Control Unit Design for Integrated Powertrain System DU Wei， ZHAO Fu tang (School of Mechanical and Vehicular Engineering，Beijing Institute of Technology,Beijing 100081，China) Abstract：The performance of the electronic unit pump(EUP)diesel engine is studied，it will be used in the integrated powertrain and its multi parameters are controllable. Both the theoretical analysis and experiment research are taken. A control unit f0r the fuel quantity and timing in crankshaft domain is designed on this basis and the engine experiment test has been done．For the constant speed camshaft driving EUP system． The fuel quantity will increase as the supply angle goes up and injection timing has no effect. The control precision can reach 1CA．The full injection timing MAP and engine peak performance corves are ℃made successfu11 Key words：electronic unit pump(EUP)diesel engine；integrated powertrain；electronic control unit. An integrated powertrain system means that the engine and the transmission should be treated as a whole．Both design method and control system deve1opment should be organized together. Generally，the best engine working points are chosen as the gearshift moment for either vehicle fuel economy or power performance． On the other hand，some researches have focused on active engine control during gear shifting. In this paper a powertrain composed of an electronic unit pump(EUP) diesel engine and an electronic automatic transmission(EAT) is studied．The controller of both the power unit and the transmission wil1 be developed and calibrated to make the engine and the transmission work rightly． To implement the operation mentioned above，as a power unit the EUP diesel engine is suitable because its injection quantity and timing are freely controllable．Based on these，some properties of the engine can be user-defined，such as the peak power curve，speed regulate mode， torque reserve coefficient etc．which is quite useful for the integrated contro1． 1. EUP Control Method The fuel injection quantity and timing control are the most important aspects to engine control unit．While the control precision is guaranteed， the resource of the system shouldn’t be expended much． The sensor mounted on the camshaft is used for stroke judgement．The signal from crankshaft is the measure reference mark of both fuel quantity and timing．Configurable timer module (CTM)and time processor unit(TPU)of the micro-controller unit (MCU)are utilized．When a CTM interrupt is triggered by the camshaft，it means that the compress stroke will come and the control unit should prepare for fuel supply．The crankshaft signal is connected to a channel of TPU that uses the PMM function．The PMM function detects a missing transition and marks the teeth number．If there exists z teeth，the span is obviously ． The control pulse is generated by PSP function combining with PMM．The PSP has two operating modes: angle-angle and angle-time. In angle-angle mode，the rising and failing edges of the output pulse are determined independently of each other．In angle-time mode，the failing edge of the output pulse is determined in reference to the rising edge．The control parameters are ANGLE1 (start angle)， RATIO1(multiple ratio1). The injection duration is decided by the last two parameters combined with the former part．We use angle-angle mode that is similar to the engine working process． The algorithm of injection quantity and timing is the best technique to guarantee the control accuracy．The angle number is an integer and the ratio is the proportion of 0×80(hexadecima1)．For example，if the span is 10CA．the resolution will be 0.1CA，which is good enough for fuel injection system．The detailed deduction could be expressed as: 2 EUP Properties Research 2．1 Injection Time Delay There exists a time delay of fuel injection．At the point of start of injection(SOI)，a drive signal is imposed on the EUP．The fue1 wil1 be injected after a short period Td that is called delay．As the EUP is a compound system，which is composed of electric，hydraulic and mechanical components，so that the delay also has those three elements[3]. This is quite meaningful for control system design for the drive pulse minus the delay part is effective for fuel quantity contro1．We get the delay by means of a piezocrystal sensot, which is mounted on the high-pressure fuel pipe near the injector．As shown in Fig.2, in the wave-form of pipe vibration there is a saltation point, at that time the fuel has been delivered to the injector. We test the delay at different engine speeds, which has clearly shown the relationship of delay angle vs engine speed. It is a nonlinear curve that the slope is big at lower engine speed and is getting small as the engine goes to a higher speed． 2．2 Fuel Quantity and Engine Speed 2．2 Fuel Quantity and Engine Speed In a definitely period of time， the fuel quantity delivered to the cylinder is decided by both the pressure change rate and the backward fuel mass rate．For the latter the fuel return is treated assembly as a pressure relief valve and we have where is the flow coefficient of the return orifice； is its section area；Po is the pressure before the orifice or we call it upstream pressure；Pc is the fuel return control pressure by which the backward fuel flow rate through a spring is controllable． When the engine speed goes higher the pressure before orifice increases while the return control pressure is still changeless．This will make the backward fuel mass rate higher．The other important thing is that the phenomenon of pressure hysteresis which is the pressure drop in the pipe costs time．The time span even will go longer as the engine speed goes up，which also makes the return fuel increase． Here we meter the fuel by the crank angle，so we have the test results in Fig.3．In Fig.3 the fuel quantity increases linearly with the fuel supply angle and the high speed one in the low position means for the same fuel injection duration the fuel mass under lower speed is more than that under higher speed． refers to the fuel quantities per cycle. 2．3 Injection Timing Injection timing is critical for engine control considering that it affects both the fuel economy and emission performance．We also investigate the effect of injection timing on the fuel quantity under the same supply angle．The pressure change rate of the unit plunge pump is expressed as [5]. where is the isothermal elastic modulus of the fuel； is the lift of the plunge while V and are their volume and cross section area． From the equation we can tell that if the mass change rate is invariable only the plunge lift speed will affect the pressure change rate．Here we use a constant slope profiled camshaft as the drive．So as the fuel supply angle increases the fuel quantity will change linearly and fuel injection timing will have no effect on the fuel quantity for no matter where injection starts．We got this in Fig.4 from which it is clearly shown that the fuel quantity is linearly increased and different injection time curves cannot change this trend． As a result, such a kind of camshaft will make the control unit design easier．Meanwhile to meet the more stringent emission regulations，the cam profile maybe need some change for good injection rate shaping．This is still in researching． 3 Experiment Research Experiment research has been done on a fourcylinder turbocharged diesel engine． It is known that the super high pressure injection system—EUP has a potential to satisfy EURO Ⅱ emission standard and even to meet EURO Ⅲ．The calibration work of the system is important． So at first，an injection timing map is made point by point considering both fuel economy and emission property．A certain working state(1400r/mm，320N/m)is selected to sample this．The angle of start injection is added step by step and it is found that NO emits more while fuel economy and exhaust temperature change less. That will decrease the emission to the opposite trend，but the angle could not be too small that will make the fuel burning after the TDC. If this happened both the fuel economy and exhaust temperature will be worse． According to this rule we make a fuel injection timing map．Fig．5 shows that the start injection angle will increase when the engine speed goes up；this is just because the mixture preparation and burning time will be long．The loads have less effect compared with the speed and we only suspend the angle in middle load area and 1400-1800 r·min engine speed．This is so called common use area of heavy diesel engine in EURO II test procedure． First we work some part load curves out．We find that the injection pulse is linear with the supply angle and the power equably while the injection timing angle can be operated freely．Finally we make the full load or the peak power curves in Fig.6．For the speed stabilization consideration we invalidate the fan silicon clutch， which will make the fuel economy 10g／(kw·h) more than the actual value．The high pressure makes the injection duration less．We can see the maximum angle is 30CA of the rated point including injection delay that property is beneficia1 to future high speed and heavy duty diesel engine．By the online calibration tool-CUCAS (common used calibration system) we have developed．the rated power curve，the slop of speed regulate，the torque reserve coefficient can be defined freely for different purposes of use．For the fuel injection timing can be controlled，as you want at any points，all this make the integrated control meaningfu1．In other words，the active control of engine during transmission period promotes the quality of gearshift itself． 4 Conclusions Based on all the research work mentioned above，we have the following conclusions 1 Mounting the EUP on the diesel engine would make the engines fuel quantity and timing contro11able．As it is used as the power unit of the integrated powertrain，more parameters can be operated． 2 Mounting the EUP on the diesel engine would make the engines fuel quantity and timing control 1able．As it is used as the power unit of the integrated powertrain，more parameters can be operated． References： [1] Hong Keum—Shik，Yang Kyung—Jinn，Lee Kyo-II．An object—oriented modular simulation model for integrated gasoline engine and automatic transmission control[R]． SAE 1999—01—0750，1999 [2] Pettersson Magnus，Nielsen Lars．Gear shifting by engine control[J]．IEEE Transactions on Control Systems Technology，2000，8(3)：495—507． [3] Zhang Jingguo，Chen Bing， Wang Zhi gang，et a1．Experimental research on performance of great flow rate and high speed solenoid valve used for electronically controlled diesel engine[J]．Transactions of CSICE，2003。21(3)：252—256．(in Chinese) [4] Liu Bolan．Electronic unit pump diesel engine control system research and development based on RTOS theory [D]．Beijing：School of Mechanical and Vehicular Engineering，Beijing Institute of Technology，2003．(in Chinese) [5] Duleba G S，Ginsburg C W ， Harrison J E．Hydraulic system modeling， steady-state analysis simulation and control system analysis using a lumped mass approach[M]．[s．1．]：[s．n．]，1994．1—11 [6] Mori K ．Worldwide trends in heavy—Duty diesel engine exhaust emission legislation and compliance technologies [R]．SAE 970753，1997．