【正文】 應(yīng)當(dāng)注意的是，這樣的冷卻液系統(tǒng)的主要好處是在怠速運(yùn)轉(zhuǎn)情況下獲得本次調(diào)查不能使用這樣系統(tǒng)提出了充分的理由。 CONTROL VALVE COOLANT SYSTEM – The coolant system, shown in Figure 6c, is that of a simple electric installation. This allows the coolant flow through the engine and the EGR cooler to be regulated throughout the operating range of the engine. It should be noted that the major benefits of such a coolant system will be gained at idle operation and, as such this investigation can not be used to provide full justification for such a system.電動泵和控制閥冷卻系統(tǒng)：如圖6c所示的冷卻液系統(tǒng)就是一個簡單的電氣裝置。因此，泵的功率需求相比較常規(guī)系統(tǒng)中的泵功率減少了約8%。類似的，在其他工作條件下，泵的流量減少約為3%至4%。Operating PointsPerformance ParameterABCEngine Power, kWFuel Cons., g/kW h230228223Pump Power, kWHeat Rejection, kWEngineEGR CoolerTotalCoolant Flow, litre/minEngineEGR CoolerTotalCoolant Temp. Rise, 176。這降低了整體泵的流量和功率的要求。因此，在額定功率條件下，廢棄再循環(huán)冷卻需求是遠(yuǎn)小于冷卻系統(tǒng)容量，通過流動的廢氣再循環(huán)冷卻器被節(jié)流控制。ELECTRONIC CONTROL VALVE COOLANT SYSTEM The coolant system, shown in Figure 6b, is that of a conventional installation with an additional control valve installed in the EGR cooler leg of the circuit. This allows the coolant flow through the EGR cooler to be regulated based on the heat rejection requirement from the EGR system. Thus, at the rated power condition, where the EGR cooling demand is much less than the cooling system capacity, the flow through the EGR cooler leg is throttled back. Conversely, at point C operation the valve is fully opened and the pump flow is more evenly distributed across the engine and EGR cooler. This reduces the overall pump flow requirement and therefore pump power. The data in Table 2 summarizes the performance of the engine with this modified coolant system.電子控制閥冷卻系統(tǒng)：如圖6b所示的冷卻液系統(tǒng)是與一個傳統(tǒng)的附加了一個額外的控制閥安裝在廢棄再循環(huán)冷卻器的回路上。該廢氣再循環(huán)率在額定功率和相應(yīng)的廢棄再循環(huán)冷卻器負(fù)載高于目前生產(chǎn)的典型發(fā)動機(jī)。CEngineEGR CoolerTable 1. Simple Coolant Circuit – Performance ResultsThe results for the baseline model illustrate an aggressive EGR strategy. The EGR cooler heat rejection of kW at rated speed corresponds to an EGR rate of 9%. This EGR rate at rated power and the corresponding EGR cooler heat load are higher than typical engines currently in production. However, it is representative of strategies that will have to be developed in the future to meet emissions targets.基準(zhǔn)模型的結(jié)果說明了一個積極的EGR策略。數(shù)據(jù)還表明，在高EGR條件下，℃。表1中的結(jié)果表明發(fā)動機(jī)的功率和冷卻泵的功率以及與之相對應(yīng)的冷卻系統(tǒng)流量和散熱信息。Having sized the system to match these operating parameters, the baseline performance characteristics for the three operating points were generated. The results in Table 1 show the engine power and coolant pump power as well as the corresponding coolant system flow rates and heat rejection information. Also, if we assume that the other auxiliary loads placed upon the engine in actual operation, due to electrical loads and A/C loads, is 4 kW then the pump power is approximately % of the total power requirement. The data also shows that at the high EGR condition, point C, the flow through the cooler circuit produces a coolant temperature rise of 176。在冷卻器流量最大的條件下，而發(fā)動機(jī)轉(zhuǎn)速最小時，確定可以接受的冷卻劑出口溫度，使得它有一個合理的沸點(diǎn)安全裕度。C, which resulted in a EGR cooler coolant flow at point C of litre/min.在EGR冷卻器的目標(biāo)是略有不同的。在這種情況下，最小流量的目標(biāo)就被確定了，即冷卻液溫度上升7℃。在這樣的安裝方式下，通過發(fā)動機(jī)和EGR冷卻器的控制孔和泵調(diào)節(jié)流量。C. In this case, the minimum flow target was chosen, . coolant temperature rise of 7176。但是，可能帶來好處和權(quán)衡的討論也包括在其中。峰值扭矩的B點(diǎn)是在溫和的EGR和發(fā)動機(jī)適度熱符合時被選為關(guān)鍵操作點(diǎn)。因此，發(fā)動機(jī)散熱是最主要的。因此，在一下的操作條件中進(jìn)行選擇。此外，從EGR策略圖可以看出，圖2中在發(fā)動機(jī)的操作范圍內(nèi)，有一個非常寬范圍的EGR水平。In reality, the engine will operate over an undetermined duty cycle, potentially including a significant amount of time idling at overnight stops (mon on intercity trucks to keep the engine warm in winter and to provide air conditioning in the summer). However, legislative test procedures, now and future, concentrate on emissions at rated power, and part speed/part load conditions and near the peak torque operating points. Also, as can be seen from the EGR strategy map, Figure 2., there is a wide range of levels of EGR over the operating range of the engine.在實(shí)際中，發(fā)動機(jī)將工作在一個不確定的占空比下，可能包括一個在通宵停工時顯著的大量時間空轉(zhuǎn)(常見的是，在冬季讓發(fā)動機(jī)提供保暖，在夏季讓發(fā)動機(jī)提供空調(diào))。為了四個概念的比較這提供了良好的基礎(chǔ)。第二閥(EV2)使用來自溫度傳感器(TS)的反饋以確定其位置。泵的速度是由溫度傳感器和閥的位置的反饋來確定。以用于回路6b類似的方式控制電動閥。與第一控制系統(tǒng)唯一的區(qū)別在于，現(xiàn)在泵的轉(zhuǎn)速不再依賴于發(fā)動機(jī)的轉(zhuǎn)速。這將允許基于原型開發(fā)的第一次切割評估的實(shí)際標(biāo)定圖。一個實(shí)際裝車的閥的位置取決于發(fā)動機(jī)轉(zhuǎn)速圖、“轉(zhuǎn)矩”(這可以從一個MAP傳感器或在實(shí)際操作中控制系統(tǒng)的加油值)和EGR閥的位置。機(jī)械式溫控器的控制是在冷卻系統(tǒng)模型本身內(nèi)進(jìn)行的。Since there are multiple coolant systems, there are a similar amount of control system models. For the simple mechanical system, although there is no specific control of the system itself, the pump speed is controlled in order to match to the engine speed. The control of the mechanical thermostat is conducted within the coolant system model itself.由于有多個冷卻系統(tǒng)，有一個類似的控制系統(tǒng)模型。發(fā)動機(jī)的控制是有共同的參數(shù)組成的，例如燃料、發(fā)動機(jī)轉(zhuǎn)速以及EGR閥的位置。這是用來提高在低負(fù)載時的冷卻劑溫度和速度，從而改善散熱器的性能。電動冷卻液泵和電控閥(EV1)允許完全控制的冷卻液通過發(fā)動機(jī)和EGR冷卻器。該回路的其他部分跟第一個回路一樣，都是純機(jī)械的。控制閥的添加允許了在限制通過系統(tǒng)的冷卻器系統(tǒng)的局限的某些變化，因此將有助于通過它的調(diào)節(jié)。Figure 6b. Single Control Valve Coolant Circuit圖6單一控制閥冷劑回路The coolant flow rate through the EGR cooler is governed by the total flow rate and the respective flow resistances in the engine and cooler circuit.通過EGR冷卻器中的冷卻液的流速是由總流速和在發(fā)動機(jī)及冷卻器回路中的各自的流動阻力確定的。通過EGR冷卻器的冷卻劑被反饋到發(fā)動機(jī)的機(jī)械式自動調(diào)溫器。Figure 6a. Simple Coolant CircuitIn the simple coolant circuit, Figure 6a, the EGR cooler is connected in parallel to the engine. The outlet from the pump is split into two, analogous with an outlet from the cylinder block adjacent to the pump or directly from the pump scroll casing. The coolant that passes through the EGR cooler is fed back to the engine just before the mechanical thermostat. This ensures that the maximum pressure drop across the cooler can be achieved.如圖6a所示，在簡單的冷卻液回路中，EGR冷卻器是被關(guān)聯(lián)鏈接到發(fā)動機(jī)上。它們展示了從一個最廉價(jià)最簡單的機(jī)械系統(tǒng)，經(jīng)過嘗試和測試以后，最后形成一個復(fù)雜的電控系統(tǒng)的發(fā)展歷程。處于這個原因，數(shù)據(jù)在一個更為實(shí)際的時間步長內(nèi)間隙性地傳遞到MATLAB Simulink。這個水平的精確度需要精確的性能分析。 intermittently on a much more realistic timestep.圖5所示是其中一種發(fā)動機(jī)布局型式。A representation of the engine layout is included in Figure 5. The engine performance