变排量压缩机汽车空调制冷系统节是流元件的配置.doc

变排量压缩机汽车空调制冷系统节流元件的配置AbstractThe comparison between variable displacement compressor and fixed displacement compressor is made in this paper. On the basis of analyzing the variable displacement compressor and automotive air conditioning refrigerating system with thermodynamic expansion valve as well as the variable displacement compressor and automotive air conditioning refrigerating system with throttling tube. The automotive air conditioning refrigerating system composed of variable displacement compressor and electronic expansion valve is introduced in this paper, analysis of this system characteristic, its control method and control algorithm are described also.摘要对变排量压缩机与定排量压缩机加以比较，在分析变排量压缩机和热力膨胀阀汽车空调制冷系统以及变排量压缩机和节流管汽车空调制冷系统基础上，提出了变排量压缩机和电子膨胀阀组成的汽车空调制冷系统，并对其系统特性加以分析，提出其控制方案和控制算法。Topic words: Compressor, Air conditioning, Control valve主题词：压缩机 空调 控制阀B>1.前言为了提高汽车空调系统的运行特性和节能效果，1983年美国GM公司哈里森散热器部在原来定排量摇板式压缩机的基础上，研制开发了V-5型无级变排量摇板式压缩机1；1988年日本三电公司开发生产出7缸无级变排量摇板式压缩机2。该类用于非独立式汽车空调系统的无级变排量摇板式压缩机是根据压缩机吸气压力与设定值之差，调节摆盘箱压力与吸气压力的差值，推动摇板改变倾斜角，从而改变活塞的行程和压缩机主轴每转一周的排量，所以压缩机的排量调节使系统获得几乎恒定的蒸发工况。该类压缩机与定排量压缩机相比，具有压缩机运行连续平稳、空调送风温度波动小及节约燃油等优点。但由于其变排量特性，在配置节流元件的同时也出现了一些特殊的问题。本文在分析变排量压缩机分别与热力膨胀阀及节流短管组成的汽车空调制冷系统的基础上，提出了变排量压缩机和电子膨胀阀组成的汽车空调制冷系统。2.变排量压缩机和热力膨胀阀组成的汽车空调制冷系统热力膨胀阀是制冷系统最常使用的节流元件，变排量压缩机在系统组成时就会考虑到与热力膨胀阀的配置。图1为变排量压缩机和热力膨胀阀组成的汽车空调制冷系统示意图。图1 变排量压缩机和热力膨胀阀组成的汽车空调制冷系统示意图 1.变排量压缩机2.蒸发器3.热力膨胀阀 4.储液罐5.冷凝器 Atsuo Inoue等人对7缸变排量压缩机和热力膨胀阀组成的汽车空调制冷系统进行了试验研究，测试结果表明系统发生了振荡现象3。本文在试验研究的基础上，对热力膨胀阀进行了改进，使热力膨胀阀即使在全关时也一直保持一微量恒定旁通，这样解决了系统低空调负荷时的振荡问题，但未做此方法在高空调负荷时的试验。我们对改进后的5缸变排量压缩机和热力膨胀阀组成的汽车空调制冷系统的稳定性问题进行了试验研究和理论分析。从测试结果可以看出蒸发器出风温度Tao、压缩机排气压力Pd、压缩机摆盘箱压力Pc、蒸发压力Pe和蒸发器出口制冷剂过热度SHb都随时间发生等幅周期性变化。该系统中有两个相对独立的制冷剂流量调节装置，即变排量压缩机和热力膨胀阀。两流量调节装置均为自力式调节机构，各由不同的参数控制。变排量压缩机是根据压缩机吸气压力为控制信号来调节压缩机活塞行程和压缩机主轴每转一周的排量。热力膨胀阀是以蒸发器出口制冷剂的过热度为控制信号，对制冷剂流量进行比例调节的。由于蒸发器的热容量、制冷剂从蒸发器入口到出口的流动和状态变化、感温包的热容量、感温包毛细管的压力传递以及阀内机械动作等一系列的时间滞后，使流量调节对过热度的响应滞后。两流量调节装置之间的唯一联系是均与压缩机吸气压力有关，但是吸气压力又由压缩机控制几乎保持恒定。当系统参数或空调负荷发生变化时，一旦变排量压缩机和热力膨胀阀流量调节不匹配就会产生系统振荡。由于系统稳定性的问题没有得以解决，限制了变排量压缩机和热力膨胀阀汽车空调制冷系统的应用。3 变排量压缩机和节流短管组成的汽车空调制冷系统变排量压缩机和节流短管组成的汽车空调制冷系统是由变排量压缩机、冷凝器、节流短管、蒸发器和气流分离器组成（见图2）。与图1表示的变排量压缩机和热力膨胀阀组成的汽车空调制冷系统相比除了节流元件由热力膨胀阀改为节流短管外，还取消了冷凝器后的储液罐，并在压缩机和蒸发器之间设置了气液分离器。由于该汽车空调制冷系统的变容量特性，节流短管作为固定阻尼节流元件无法保证蒸发器出口的制冷剂在低空调负荷下的完全蒸发。因此，在压缩机和蒸发器之间设置了气液分离器，使未蒸发完的液态制冷剂分离出来，暂存于气液分离器的下部。由于该气液分离器置于高温的发动机舱内，它很快就会继续蒸发成为气态，从而保证了压缩机的安全4。 图2 变排量压缩机和节流短管组成的汽车空调制冷系统示意图 1.变排量压缩机2.冷凝器3.节流短管 4.蒸发器5.气液分离器 由于节流短管结构简单，为无反馈开环流量控制装置，保证了系统的可靠运行。所以在变排量压缩机汽车空调制冷系统中，变排量压缩机和节流短管组成的汽车空调制冷系统目前应用最广。但存在节流短管无法与变排量压缩机在变容量范围内达到系统1高效运行，气液分离出来的液态制冷剂不能再去有效地利用以及气液分离器布置困难等缺点.4 变排量压缩机和电子膨胀闪组成的汽车空调制冷系统图3为变排量压缩机和电子膨胀阀组成的汽车空调制冷系统示意图，该系统由变排量压缩机、冷凝器、储液罐、电子膨胀阀和蒸发器组成。通过输入参数进入控制器，利用控制器的控制算法得出控制电子膨胀阀的电磁线圈的电压或脉冲电机的驱动脉冲信号，从而实现了膨胀阀对流量的调节5。 图3 变排量压缩机和电子膨胀阀组成的汽车空调制冷系统示意图 1.变排量压缩机2.蒸发器3.电子膨胀阀 4.控制器5.储液罐6.冷凝器变排量压缩机制冷系统中配置电子膨胀阀的关键问题是以保证系统稳定性和变容量范围内系统最佳运行工况为目标，确定合理的控制方案和控制算法。在该系统的研究开发过程中，还有许多理论问题和实际应用问题要解决。系统静态和动态特性深入了解控制对象的特性是寻求合理的控制方案和控制算法的基础。对系统中各部件的静态和动态特性进行理论分析和试验研究，用理论建模和系统辨识相结合的方法，得出各部件的静态模型和动态模型。然后根据各部件参数之间关系，建立系统静态和动态模型。根据模拟计算和试验研究的结果，分析系统静态和动态特性。a.系统稳定性原则由于该系统有变排量压缩机和电子膨胀阀两个流量调节装置，所以同样存在系统稳定性问题。在以上系统静态和动态研究的基础上，分析满足系统稳定性条件下的电子膨胀阀特性要求，得出系统稳定性区域。b.控制方案和控制算法由于该系统有变排量压缩机和电子膨胀阀两个流量调节装置，所以同样存在系统稳定性问题。在以上系统表态和动态研究的基础上，分析满足系统稳定性条件下的电子膨胀阀特性要求，得出系统稳定性区域。c.控制方案和控制算法 为减少电子膨胀阀流量调节对过热度的响应滞后，电子膨胀阀对蒸发器出口端制冷剂过热度的检测可通过热敏电阻或压力信号。采用热敏电阻来检测时用2只热敏电阻，一个测量蒸发温度，另一个测量蒸发器出口温度；采用压力信号来测量是对蒸发器出口端压力进行测量，并经物性程序将其转化为蒸发温度。由于蒸发器内压力的变化比温度的变化迅速，因此使控制器能及时地对过热度的变化作出反应。电子膨胀阀流量调节对过热度的响应滞后问题，也可以采用前馈加反馈的复合调节方法解决。如将压缩机转速作为前馈信号，根据转速变化调节膨胀供液量，再结合反馈进行复合调节。由于系统的非线性特性，采用模糊算法有一定优势；也可考虑PID控制算法和模糊控制算法结合使用，发挥各自算法的优点，达到较好的控制效果。 5 结论a.变排量压缩机和热力膨胀阀组成的汽车空调制冷系统存在系统振荡问题。b.节流短管结构简单，为无反馈开环流量控制装置，保证了它与变排量压缩机组成的汽车空调制冷系统的可靠性运行。但存在无法与变排量压缩机在变容量范围内达到系统高效运行，气液分离器分离出来的液态制冷剂不能再去有效地利用以及气液分离器布置困难等缺点。c.变排量压缩机和电子膨胀阀组成的汽车空调制冷系统是一种最有发展前途的系统配置，代表汽车空调制冷系统的发展方向。需要对系统静态和动态特性进行深入了解，确定合理的控制方案和控制算法，以保证系统稳定性和变容量范围内系统最佳运行。参考文献 1. Skinner T J et al. V-5 Automotive Variable Displacement Air Conditioning Compressor. SAE Congress Paper 850040.2. Toyoda H et al. Historical Review of the Wobbleplate and Scroll Type Compressors. SAE Congress Paper 901737.3. Inoue A et al. Evaluation of Infinitely Variable Displacement Compressors with Thermal Expansion Valves in A Motor Vehicle Air Conditioning system. SAE Congress Paper 880052.4. 黄天泽.汽车空调系统设计与使用维修.北京：北京理工大学出版社，1997.5. 田怀璋等.电子膨胀阀技术综述.流体工程.1992，20（7）.<organization system and working mode, the selection of a number of municipal strengthening group to build innovation and strengthen the organization of the basic level organizations advanced model.(seven) the manual work of the Communist Youth League Organization published < > and < > League branch of manual work, to promote the use of two manuals in the city's organizations at various levels. The county committee, directly under the group (work) is under the jurisdiction of grassroots League and group (total) using branch ratio shall not be less than 70%.Three, to further strengthen the group's leadership and team building(a) to strengthen the league's leadership at all levels of construction. Continue to do a good job of municipal Party Committee Organization Department "on the strengthening of the Communist Youth League cadres management opinions implementation. To promote the group counties (autonomous counties, cities) Commission and city directly under the group (workers) appointed to carry out the" Five "team building activities. Improve the League Association Department working mechanism. Conscientiously fulfill the duties of CO, combined with the city group directly under (the) Committee of the general election and the adjustment, actively jointly with the unit where the party organization department good group leadership selection with the work. Do a good job in municipal Party committee assistant committee leadership and leading cadres of the annual assessment work, adhere to and improve the assistant secretary of the Communist Youth League talk system group To weave individual conversation and collective conversation, to strengthen the committees of all levels, the Standing Committee of the Standing Committee, the establishment of a sound system of central group learning, the system of investigation and study, the system of important issues and the reporting system.(two) to strengthen the work of education and training of cadres to conscientiously implement the Central Committee. "On the implementation of grassroots cadres training project and opinions on carrying out the" mission municipal CYL Cadres training project implementation opinions, full implementation of the project of the City Youth League cadres training education. Focus on the county grassroots cadres and workers focused on training, the new school system vocational training League cadres, for the Municipal Organization Department jointly held the third session of the Communist Youth League system training cadres in party. Focusing on the construction of new socialist countryside, strengthening village cadres and rural construction team group member of the young team, the county organizations at various levels throughout the year is expected to train 100 00 rural grassroots cadres, plans to train 1000 village secretary of the village Party branch.(three) actively promote grassroots cadres election work. Under the unified leadership of the party organization, to strengthen grassroots organizations direct work, standardize the election work rules and procedures, in the designated candidate, open competition to democratically elected branch secretary at the same time, actively and steadily the development of Township, streets and other grassroots organizations in the direct election of the pilot work, on the basis of summarizing the experience and gradually expand the scope of the pilot, and gradually formed a set of measures and cadres election system.(four) to strengthen the cadres testing exercise. To study the development of <XX city from 2006 to 2008 cadres testing exercise planning. To select outstanding cadres to the central mission in Beijing, Shanghai, Guangzhou and other central organs and sending work in developed areas. With the Central Committee the implementation of the western region and ethnic minorities cadres training plan "". To carry out the eighth batch of municipal organs attachment cadre management, selection, training work. The outstanding cadres to start the National Development Bank XX branch testing exercise.(five) to strengthen the group construction. The main position to play the role of Youth League cadre education and training as the city, in accordance with the requirements of post training, further curriculum scientifically and rationally, adopt "arrangement menu" course, basic theory includes group work, focus, hot and difficult issues, to enhance the content and practice; to strengthen the construction of teaching staff, the integration of teachers, establish a quality teacher training team, establish and implement course evaluation system; take delivery of training to the countryside, on-site training, and increase the rural grassroots cadres training efforts.Four, efforts to strengthen the work of young talent(a) to tenth XX young 54 medal in recognition of the publicity, and actively explore the XX youth service. 54 Medal of institutionalization, standardization and socialization mechanism. Give full play to the XX award in recognition of 54 youth medal Association, Youth Award winner in the 54 chapter, investigation activities. Who won the Youth Service medal, dedication to the society to create conditions, build the stage. During the 54, named in recognition of the tenth XX young 54 medal. The association of <XX editing of young talent ", the exchange of information and communication platform for the XX of outstanding young talents.(two) the establishment of municipal Party committee of young talent information database. In accordance with the "feasible, effective, classification management, implement step by step" principle, the establishment of municipal Party committee of youth talent database; guiding organizations at various levels generally established the young talent database, construction of city, county (directly under the Communist Youth League), grassroots organizations three young talent information database the relevant information collection system, and gradually establish the city's young people, the Communist Youth League youth talent information network, provide information platform for young talent resource development.Five, take effective measures to strengthen the mission management(a) to strengthen the mission management work. Strengthen the dues collection and management, continue to adhere to the dues collection regularly reporting system, the annual comprehensive award in recognition of the tour and the tour one vote veto system audit system. Do statistical work in the group. The group service award in recognition of the advanced units, standardization, promoting group management work institutionalized.(two) to strengthen the organization of research and information exchange efforts. Grassroots carry out research, efforts to form a number of theoretical results. Make full use of the network carrier, to explore the establishment of electronic group service system, promote the work of Communist Youth League information.Attachment 4:XX municipal Party Committee Propaganda Department of the Communist Youth League work pointsIn 2006, the Communist Youth League propaganda ideological work XX to Deng Xiaoping theory and the important thought of "Three Represents" as guidance, study and implement the party's sixteen and the spirit of the the fifth Plenary Session of the 16th CPC Central Committee implementation of the eight plenary session of the two committee, the city's cultural work conference, the Propaganda Department of the meeting and the the fourth Plenary Session of the 15th CPC Central Committee permanent mission spirit, closely around "11th Five-Year XX" the goal of full implementation of Scientific Outlook on Development, emancipating the mind, seeking truth from facts, keep pace with the times, close to reality, close to life, close to the young, persevere grasp orientation, grasping deepening, grasping construction innovation, further improve the group's propaganda and ideological work ability, unity To guide the majority of members of the youth to achieve the "11th Five-Year" planning tasks, the overall construction of a well-off society, building a socialist harmonious society to make new contributions.One, adhere to the "Three Represents" important thought and Scientific Outlook on Development education to guide the youth, to further strengthen the ideological and political education of youth(a) armed with youth science theory. Unremittingly with Deng Xiaoping theory and the important thought of "Three Represents" armed members of youth education, to promote the study and implement to expand the depth and breadth. To study and implement the important thought of "Three Represents" with the establishment and implementation of Scientific Outlook on Development combine with the implementation of the requirements of constructing socialist harmonious society with Scientific Outlook on Development, carry out education as an important part of the theory of armed youth in the new period, strengthen the establishment and implementation of Scientific Outlook on Development education, educate and guide the youth to fully understand the great significance of establishment and implementation of Scientific Outlook on Development, in-depth understanding of the Scientific Outlook on Development era back The king, the practice foundation, basic connotation, historical status, spirit and practice requirements, a profound understanding of Scientific Outlook on Development with Marxism Leninism, Mao Zedong thought, inheriting and developing relationship between Deng Xiaoping theory and the important thought of "Three Represents", to help young people establish and consciously practice Scientific Outlook on Development. Persist in learning, grasping the backbone, grasp the practice, grasp the opportunity. Catch club, effective way to grasp the network, with the group of cadres, young students and young backbone fronts as the focus, to promote the work of the armed youth theory to develop in depth, to help the youth continue to firm ideals and beliefs, to build a powerful spiritual pillar. To carry out the study and implementation of the party's sixteen session of the five Eight plenary session