【正文】 model is executed on a crank angle basis and results are output as cycle averaged values after each pleted cycle. This level of fidelity is required for accurate performance analysis. Obviously, to run the rest of the model at this timestep would mean that a high level of processing power is needed. For this reason, data is passed to MATLAB174。Figure 5. Engine Model LayoutENGINE MODEL The model of the engine includes definition of the intake and exhaust manifolds, including the EGR system, and allows for control of various engine parameters such as EGR rate, engine speed, fueling etc.發(fā)動機型號發(fā)動機模型包括定義的進氣和排氣歧管，包括廢氣再循環(huán)系統(tǒng)，并允許控制各種發(fā)動機參數(shù)，如廢氣再循環(huán)率，發(fā)動機轉速，燃油等。此數(shù)據(jù)主要涉及在發(fā)動機內冷卻液的熱抑制和EGR冷卻器。 interface.獲取物理數(shù)據(jù)是建模目的的最直接的需求。這種類型的數(shù)據(jù)流只是來自于控制系統(tǒng)，或只有一個發(fā)動機或冷卻系統(tǒng)數(shù)據(jù)積累的其他車型。Control data is that used by the control system whether in actuation or feedback from a sensor. This data will be transmitted to the electronic control module in the realworld application. The flow of this type of data is only to and from the control system and only one of the other models, the engine or coolant system, has knowledge of this data.控制數(shù)據(jù)是由控制系統(tǒng)使用，無論來自于傳感器的動作或反饋。此數(shù)據(jù)分為兩個不同的類型，分別是控制數(shù)據(jù)和物理數(shù)據(jù)。這些模塊的主要功能是從一個系統(tǒng)模型傳輸數(shù)據(jù)到另外一個，無論是在Simulink174。 or the other codes, to another. This data falls into two distinct types, control data and physical data. The flow of information municated can be seen in Figure 4.模擬控制和通信：正如前面所討論的，仿真的控制和系統(tǒng)模型之間的通信全部在Simulink174。 COMMUNICATION – As discussed earlier, the control of the simulation and munication between the system models is conducted by blocks within Simulink174。對于長期(＞1000秒)的測試文件，這是合理的結果。Simulink174。 was set to run at sec and Simulink174。因此，如果所有的模塊采用整數(shù)倍的采樣時間，然后協(xié)同仿真應該從對話框中繼承最快的時間。協(xié)同仿真S函數(shù)的當前配制繼承了Simulink174。 system. Thus, if all blocks have integer sample times, then the cosimulation should inherit the fastest time from the dialog box.由于這個原因，在Simulink174。For this reason, sample times of all blocks in the Simulink174。以更快的(或等于)一個整數(shù)倍速率運行S函數(shù)。 running at a faster (or equal) rate that is an integer multiple of the rate of the SFunction execution. For example, if FLOWMASTER174。只是監(jiān)測狀態(tài)，其中一小部分的模型仍然采用FLOWMASTER174。S函數(shù)仍然使用Simulink174。)的信息交流。其余部分的仿真隨后在此處輸出。因此，Simulink174。 utilizes.傳統(tǒng)上，S函數(shù)是用來描述某種動態(tài)系統(tǒng)，即系統(tǒng)的輸入、輸出和狀態(tài)。). The client program handles the integration and other putations required to advance its simulation. The SFunction therefore still uses inputs, outputs and states, although Simulink174。Traditionally, an SFunction is used to describe some sort of dynamic system, . a system that has inputs, outputs, and states. It may contain integrators, derivatives and other equations that are used to pute the states and outputs of the system. Therefore Simulink174。Simulink174。 和FLOWMASTER174。這里開發(fā)的協(xié)同仿真軟件使用的是MATLAB174。中開發(fā)以了一個腳本，這將啟動FLOWMASTER174。的鏈接：結合FLOWMASTER，里卡多已經在MATLAB174。, through an Mfile Sfunction.MATLAB174。 and FLOWMASTER174。 solver module and provide munication to and from it. The cosimulation developed here uses DCOM software technology to municate between the software platforms of MATLAB174。 Simulink174。 TO FLOWMASTER174。因此，繼續(xù)向上鏈接的研究是有所必要的。但是這僅僅是通過FLOWMASTER174。提供了一個鏈接到MATLAB174。 as the information and link manager. Thus, in order for this study to proceed a link in the opposite direction was desired.圖4說明了協(xié)同仿真體系架構和信息流的模型。 Simulink174。 Information FlowFigure 4. illustrates the cosimulation architecture and flow of information within the models. Currently,FLOWMASTER174。最后，冷卻系統(tǒng)的建模使用FLOWMASTER174。 Simulink174。發(fā)動機的性能模型是仿照里卡多的市售軟件WAVE，其中包括了在發(fā)動機和廢氣再循環(huán)(EGR)系統(tǒng)的氣體動力學影響。是用于模擬冷卻系統(tǒng)的控制。.首先，MATLAB174。 Simulink174。 Simulink174。在這個研究中，三個商用的一維代碼以這種方式相互聯(lián)系，以建立一個完整的發(fā)動機性能模型(包括氣體動力學)，冷卻系統(tǒng)和控制系統(tǒng)。仿真研究了其他應用程序和討論過的其他出版物的好處。這是非常有用的，因為每個模型是分開運行，所以可以快速模擬出恰當?shù)膹碗s程度。通常下一步是建立更復雜的個別代碼模型。最簡單的方法是分析得出一個模擬了一個系統(tǒng)或多個系統(tǒng)的一個單一代碼的模型。這項工作包括研究主動組件，并包括電磁冷卻閥和電動水泵。本文所說的分析工具可以幫助設計冷卻系統(tǒng)，以及幫助校準車輛控制器。). The intention of this analysis tool is to aid in the design of the coolant system as well as to help calibrate the vehicle controller.為了做到這一點，里卡多已經制作出詳細的模型，可以模擬發(fā)動機，廢氣再循環(huán)及冷卻系統(tǒng)的動態(tài)系統(tǒng)之間的相互作用。) and control system analysis (MATLAB174。因此，有必要仔細研究當一個大卡車發(fā)動機由于增加了冷卻的廢氣再循環(huán)系統(tǒng)對汽車冷卻系統(tǒng)的影響。那是因為，冷卻系統(tǒng)的工程師很少了解冷卻系統(tǒng)對發(fā)動機性能的影響，反之亦然。然而，為了獲得最好的設計，為了獲得最恰當?shù)娜加徒洕?、排放、乘員的舒適性、以及更詳細地成本，這都是最有必要的。因此，把EGR冷卻器對冷卻系統(tǒng)的反饋盡量減少。因此，在發(fā)動機低速時水泵需要提供恰當溫度和流速的冷卻水到EGR冷卻器，在發(fā)動機額定轉速情況下沒有產生過大的冷卻水流量和壓力上升，避免在廢氣EGR冷卻器里沸騰。圖3所示的是卡車發(fā)動機的廢氣再循環(huán)散熱曲線。From this it can be seen that the high levels of EGR occur at the part load and part speed conditions. Taking into account the total mass flow rate of exhaust gas and the exhaust gas temperature, the required heat rejection from the EGR can be calculated. Figure 3 shows a plot of EGR heat rejection for a truck engine.從這可以看出，在部分負荷和部分速度條件下產生高水平的廢氣再循環(huán)。事實上，在大多數(shù)應用中的冷卻能力冷卻一側不僅僅是足以應付需要。傳統(tǒng)上，在發(fā)動機額定功率工況附近的發(fā)動機峰值時拒絕熱冷卻系統(tǒng)，如圖1所示。It is also anticipated that future diesel engines will make use of cooled EGR in order to meet the performance and emissions levels required. This places further demands on the cooling system that need to be managed appropriately. Traditionally, the heat rejected to cooling systems by the engine peak around the rated power condition of the engine, as illustrated in Figure 1. This plot also illustrates that the heat rejected by the engine at low speeds and loads is relatively small pared to the peak level. In fact, in most applications the cooling capacity on the coolant side is more than enough to cope with the demand.我們預計，未來柴油發(fā)動機使用EGR冷卻，以滿足性能的需要和排放水平的需求。此外，推動提高燃油經濟性，特別是7和8類卡車，需要降低風阻系數(shù)和迎風面積。 8 trucks, requires reduced drag coefficients and frontal area. Since the cooling pack in the vehicle has a major influence on frontal area, it is important that the thermal management of the cooling requirements be given a high priority.由于包裝和造型的限制，當前車輛冷卻系統(tǒng)的性能已經非常有限。這是通過使用市面上一維協(xié)同仿真代碼。由于廢氣再循環(huán)(EGR)冷卻器的增加導致該系統(tǒng)設計更加復雜是個現(xiàn)實問題，特別是在部分負載和低轉速條件下，而冷卻系統(tǒng)通常被設計處理的是在額定功率情況下的最大熱負荷時的發(fā)動機工況。首先，由于增加的廢氣再循環(huán)(EGR)可能會導致發(fā)動機冷卻系統(tǒng)的流量和散熱的額定功率增大。Heavy Duty Truck Cooling System Design Using CoSimulation重型汽車冷卻系統(tǒng)設計中的協(xié)同仿真應用ABSTRACT摘要In order to meet the legislated emissions levels, future diesel engines will like