【正文】 壓力、更快的開關(guān)時間，以及根據(jù)發(fā)動機(jī)工況修訂的可變的流量速率曲線，已經(jīng)使得柴油發(fā)動機(jī)具有良好的經(jīng)濟(jì)性、低污染、高動力性，因此柴油發(fā)動機(jī)甚至進(jìn)入了豪華高性能轎車領(lǐng)域。同時，噴油量必須精確計(jì)算，燃油流量速率曲線必須有精確的計(jì)算模型，預(yù)噴射和二次噴射必須能夠完成。共軌系統(tǒng)包括以下幾個主要的部分： ①低壓部分，包含燃油共軌系統(tǒng)組件。電控柴油機(jī)系統(tǒng)EDC主要由系統(tǒng)模塊，如傳感器、電子控制單元和執(zhí)行機(jī)構(gòu)組成。它們擁有一個可以快速開關(guān)噴嘴的執(zhí)行閥(電磁閥或壓電觸發(fā)器)，這就允許對每個氣缸的噴射進(jìn)行控制。在共軌燃油噴射系統(tǒng)中，燃油噴射和壓力的產(chǎn)生是分開的。EDC控制每個組件。燃油噴射和壓力的產(chǎn)生是通過蓄能器分離開來。由發(fā)動機(jī)驅(qū)動的連續(xù)運(yùn)轉(zhuǎn)的高壓泵提供所需噴油的壓力。由于幾乎一致的噴油方式，高壓泵的設(shè)計(jì)可以小的多，而且它的驅(qū)動轉(zhuǎn)矩可以比傳統(tǒng)燃油噴射系統(tǒng)低，這源于高壓泵的負(fù)載很小。(2)壓力控制所應(yīng)用的壓力控制方法主要取決于系統(tǒng)。不需噴射的燃油通過壓力控制閥流回到低壓回路。在第一批共軌系統(tǒng)中采用了對高壓側(cè)的控制。另一種控制軌道壓力的方式是進(jìn)口端控制燃油供給。發(fā)生故障時，壓力安全閥防止油軌壓力超過最大值。這對燃油消耗起到積極的作用。雙執(zhí)行器系統(tǒng)也是一種控制軌道壓力的方式，它通過計(jì)算單元對壓力進(jìn)行控制，并且通過壓力控制閥對高壓端進(jìn)行控制，因此同時具備高壓側(cè)控制與進(jìn)口端燃料供給控制的優(yōu)勢。它們由與燃油軌道直接相連的短高壓油軌提供燃油。噴油器的開啟時間和系統(tǒng)油壓決定了燃油供給量。(4)液壓輔助動力與傳統(tǒng)燃油噴射系統(tǒng)相比，將壓力的產(chǎn)生與燃油的噴射分離開來，有利于燃燒室的充分燃燒。目前最高燃油壓力為1600巴，將來會達(dá)到1800巴。通過多次觸發(fā)高速轉(zhuǎn)換閥的開閉可以在每個噴射周期內(nèi)實(shí)現(xiàn)多達(dá)5次的噴射。(5)控制和調(diào)節(jié)發(fā)動機(jī)的控制單元通過傳感器檢測加速踏板的位置以及發(fā)動機(jī)和車輛的當(dāng)前工況。電控單元處理輸入信號。噴油器的開關(guān)時間應(yīng)很短，采用優(yōu)化的高壓開關(guān)閥和專業(yè)的控制系統(tǒng)即可實(shí)現(xiàn)。電控柴油機(jī)系統(tǒng)(EDC)可以實(shí)現(xiàn)對燃油噴射量的精確計(jì)算。其基本功能包括對柴油燃油噴射正時的精確控制，和在給定壓力下對油量的控制。其他開環(huán)和閉環(huán)控制功能用于減少廢氣排放和燃油消耗，或提供附加的可靠性和便利性，具體例子有：① 廢氣在循環(huán)控制； ② 增壓控制； ③ 巡航控制；④ 電子防盜控制系統(tǒng)等。由于發(fā)動機(jī)控制單元通常最多有8個噴油器輸出口，所以超過八缸的發(fā)動機(jī)需要兩個控制單元。一些功能被 分配給某個特定的控制單元(如燃料平衡控制)，其功能根據(jù)需求情況(如檢測傳感器信號)可以動態(tài)地分配給一個或多個控制單元。② The highpressure system, prising ponents such as the highpressure pump, fuelrail, injector, and highpressure fuel electronic diesel control(EDC), consisting of system modules, such as sensors, the electronic control unit, and key ponents of the monrail system are the are fitted with a rapidaction valve(solenoid valve or piezotriggered actuator)which opens and closes the permits control of the injection process for each the injectors are fed by a mon fuel rail, this being the origin of the term “mon rail”.In the monrail fuelinjection system, the function of pressure generation and fuel injection are injection pressure is generated independent of the engine speed and the injected fuel electronic diesel control(EDC)controls each of the ponents.(1)Pressure generation and fuel injection are separated by means of an accumulator under pressure is supplied to the accumulator volume of the monrail ready for continuously operating highpressure pump driven by the engine produces the desired injection in the fuel rail is maintained irrespective of engine speed or injected fuel to the almost uniform injection pattern, the highpressure pump design can be much smaller and its drivesystem torque can be lower than conventional fuelinjection results in a much lower load on the pump highpressure pump is a radialpiston mercial vehicles, an inline fuelinjection pump is sometimes fitted.(2)Pressure Control The pressure control method applied is largely dependent on the way of controlling rail pressure is to control the highpressure side by a pressurecontrol not required for injection flows back to the lowpressure circuit via the pressurecontrol type of control loop allows rail pressure to react rapidly to changes in operating point( the event of load changes).Control on the highpressure side was adopted on the first monrail pressurecontrol valve is mounted preferably on the fuel some applications, however, it is mounted directly on the highpressure way of controlling rail pressure is to control fuel delivery on the suction metering unit flanged on the highpressure pump makes sure that the pump delivers exactly the right quantity of