1 柴油機電控燃油動力系統(tǒng)設(shè)計  1 EUP 控制方法  燃料噴射時時控制系統(tǒng)最重要的是發(fā)動機操控單元，它保障控制精度來達到  能量消耗最少的要求。  傳感器的信號是來自對凸輪軸位置的檢測，信號是對曲軸測量參數(shù)，即噴油量和噴油時間的關(guān)系。微型調(diào)速器 (MCU)是由計時器結(jié)構(gòu)模塊 (CTM)和定時處理部件 (TPU)控制的。當(dāng)計時器結(jié)構(gòu)模塊被凸輪軸觸發(fā)器中斷，控制部件將為燃料供給系統(tǒng)作出相應(yīng)的反應(yīng)，集中維護模塊中的曲軸信號連接定時處理部件 (TPU），集中維護模塊檢測出一個脈沖和齒數(shù)。如果存才 Z 個齒，那么跨度就是 360 /o z 。  脈沖式控制器由 PSP 和 PMM 相結(jié)合發(fā)出的， PSP 有兩種工作方式，角 角、角 時間，在角 角工作模式中，上升沿和下降沿的輸出脈沖與兩者沒有關(guān)系。在角 時間工作模式中，下降沿的輸出脈沖取決于上升沿，其控制參數(shù)是 ANGLE1開始角和 ANGLE1 結(jié)束角。噴油時間是由 EUP 的兩個參數(shù)控制。噴射時間取決于以上兩個參數(shù)的位置結(jié)合。我們使用的是角 角工作模式來對發(fā)動機工作的控制。  圖 1-1 邏輯控制電路控制噴射量和噴射時間圖  對于噴油量和噴油時間的計算方法是保證提前角的控制精度，角度 應(yīng)是個整數(shù)，并且與十六進制成比例。例如：一個距離是 010CA ，那么結(jié)果就是 00.1CA 。關(guān)于合適的燃料噴射系統(tǒng)，通常用下面公式表示 ：  12223 6 0 /( ) / ( 1 )( ) / ( 1 2 8 )( ) / ( 1 )( ) / ( 1 2 8 )iiiididtzN t D tr t D t tN t D tr t D N t t 2 2 EUP 的研究  2.1 噴射時間的延遲  一個燃料噴射延遲的開始位置是由 EUP 發(fā)出的驅(qū)動信號來控制的，燃料的  噴射在一個短期內(nèi)的倍增稱之為噴射延遲。 EUP 是一個復(fù)雜的控制系統(tǒng)，由電子單元、液壓、機械部件組成，所以這個延遲是三元化的。這意味著控制系統(tǒng) 的設(shè)計是由驅(qū)動脈沖延遲部分來對噴射量進行有效控制，延遲是由一個壓電晶體傳感器來控制的，它位于高壓油管上，例如圖 2-1，燃油噴射時間由噴射器控制，延遲在不同的發(fā)動機轉(zhuǎn)速下進行試驗，用延遲角表示。發(fā)動機在較高的轉(zhuǎn)速下運轉(zhuǎn)時則是一條非線性的曲線，發(fā)動機在低速時的曲線斜率較大。  圖 2-1  噴射延遲波形  2.2 噴油量和發(fā)動機轉(zhuǎn)速  在一定的時間內(nèi)，噴射到氣缸的燃油取決于壓力變化和燃料的比率。因為后者燃料的回收取決于泄壓閥和公式 2-1：   002dCm C A P P                      （ 2-1）  dC是燃油回流系數(shù)，0A是表面積，0P是在出口或在出口之前的輸出壓力，CP是燃料在裝有可調(diào)節(jié)彈簧的空值桿上的作用力。當(dāng)發(fā)動機轉(zhuǎn)速上升到較高的壓力時，監(jiān)測口處的德操縱桿上的力是靜止不變的，它以較高的比率反饋到燃料模塊上，另一項重要的就是壓差數(shù)值是管內(nèi)的壓力滯后，這個時間間 隔會使發(fā)動機長時間地高速運轉(zhuǎn)，從而使燃油回流增加，在圖 2-2 中，燃料噴射量的增加同燃料供給角、高轉(zhuǎn)速的最低位置的計算、燃料噴射持續(xù)時間成線性關(guān)系，并且大于對低速的要求。fcm是每個噴射循環(huán)的噴油量。   3 圖 2-2 發(fā)動機轉(zhuǎn)速與噴射量圖  2.3 噴油定時  噴油定時的作用是控制發(fā)動機燃料經(jīng)濟性和動力性的關(guān)鍵，有效的噴油時間就是燃料時間滯后一個供給角，單位壓力燃油泵的變化率可以表示為式 2-2：  1TPd m d hpAV d t d t            （ 2-2）  T為燃料彈性模量， h 為噴油量的增量，PA為燃油管的體積和橫截面，等式中如果全部的參數(shù)是唯一不變的，噴油量的上升速度會影響壓力的變化。使用一個斜率為常數(shù)的凸輪軸作為驅(qū)動輪，燃料供給角的增加量則開始線性變化。從圖2-3 中可以得到燃料噴射量是線性增加的，這條曲線在不同的噴射時間下不會改變。   圖 2-3  噴油時間與噴油量  3 實驗研究  測試工作已 經(jīng)在一個四氣缸的渦輪增壓柴油機上完成了。  眾所周知，超高壓噴射系統(tǒng)的 EUP 可以滿足歐洲 II排放標(biāo)準(zhǔn)，有的甚至可 4 以滿足歐洲 III 排放標(biāo)準(zhǔn)。對噴射系統(tǒng) EUP 的校準(zhǔn)工作是非常重要的，其關(guān)鍵部分是噴油時間，即燃料的經(jīng)濟性和動力性，在 1300r/min, 32N/m 的工況下進行試驗得到了這些數(shù)據(jù)，從噴射角開始，在燃油經(jīng)濟性和排氣溫度變化很小的情況下檢測檢測 NO 的濃度是否增加，減少 NO 的濃度是一個趨勢，而且噴射起始角越小，燃料燃燒效果就越好。反之，尾氣排放、燃油經(jīng)濟性和排氣溫度就會越差。  根據(jù)這種規(guī)律我們繪制出了燃油噴 射圖（圖 3-1）。圖中表示了發(fā)動機轉(zhuǎn)速升高時，噴射角開始增加，所以混和氣控制裝置的工作時間也會增加，當(dāng)負(fù)荷減少時，噴射角則相應(yīng)減小，發(fā)動機轉(zhuǎn)速下降到 1400r 1800r/min 時，這種圖譜則適應(yīng)重型柴油機的燃料噴射規(guī)律。  圖 3-1 燃油噴射圖  工作的第一步是繪制出載荷曲線，我們發(fā)現(xiàn)噴射脈沖與供給角呈線性關(guān)系，功率在噴射時間上可以自由控制，根據(jù)此種規(guī)律繪制出了滿載負(fù)荷時和極限功率曲線圖 3-2 圖 3-2 滿載負(fù)荷時和極限功率曲線圖  考慮到速度穩(wěn)定性，首先讓硅 油離合器停止工作，使燃油經(jīng)濟性達到10 /g kw h ，甚至超過這個數(shù)值。高壓持續(xù)噴射時間相應(yīng)減少，在此我們可以得 5 到極限角 030CA 的額定點，噴射延遲性是對高速柴油機包括重負(fù)載柴油機在內(nèi)都是有很大幫助的。時時校準(zhǔn)工具 CUCSA 對額定功率曲線、燃油速度的調(diào)節(jié)、扭矩儲備系數(shù)都可以自由地控制，因為不同的工作狀況都是適用的。在不同的燃料噴射時間內(nèi)都是可以人為控制?？傊?，發(fā)動機控制系統(tǒng)可以在不同的速度范圍內(nèi)進行控制。  4 結(jié)論  以上的研究是以 下面三個條件為基礎(chǔ)進行研究的。  1，根據(jù)柴油機 EUP 來設(shè)計發(fā)動機燃油噴射量進行實時控制，按照發(fā)動機動力裝置傳遞，控制系統(tǒng)中的諸多參數(shù)。  2，燃油噴射時間圖譜和發(fā)動機功率峰值性能曲線的完成，可以精確的控制曲柄轉(zhuǎn)角達到 01CA   6 Electronic Unit Pump Diesel Engine Control Unit Design forIntegrated Powertrain System 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 shouldnt 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 360 /o z  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  7 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 080(hexadecima1) For example， if the span is 10 CA the resolution will be 0.1 CA， which is good enough for fuel injection system The detailed deduction could be expressed as: 12223 6 0 /( ) / ( 1 )( ) / ( 1 2 8 )( ) / ( 1 )( ) / ( 1 2 8 )iiiididtzN t D tr t D t tN t D tr t D N t t 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 elements3. This is quite meaningful for control system design for the  8 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 dCis the flow coefficient of the return orifice；0Ais 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  9 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 speedfcmrefers 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 T  is the isothermal elastic modulus of the fuel； h  is the lift of the plunge while V and pAare 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  10 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  emission standard and even to meet EURO 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 rmin engine speed This is so called common use area of heavy diesel engine in  11 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 (kwh) more than the actual value The high pressure makes the injection duration less We can see the maximum angle is 30 CA 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   12 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 &n