柴油机低温起动燃烧过程分析设计开题报告VIP

承德石油高等专科学校毕业设计 论文 1 开题报告 柴油机低温起动燃烧过程分析设计开题报告 承德石油专科学校汽车工程系承德石油专科学校汽车工程系管利新管利新 一一 背景背景 不采取燃烧辅助起动措施 柴油机低温启动水平一般保持在 20 以上 冬季 我国三北地区年最低气温都在 30 以下 个别地区甚至可达到 40 50 由于低温 使柴油机不能可靠启动 对普通用户来讲 仅仅表现在运输 效率降低 效益途径降低 使用范围缩小的问题 而对负担特殊使命的军用车辆 消防车辆 工程技术车辆来说 会贻误战机 造成重大灾难 二 意义二 意义 柴油机的冷起动性能的提高能直接影响油耗降低 排放达到指标 甚至 生产任务的完成 柴油机的低温起动性能又是柴油机的重要性能指标之一 它不 仅关系到整机的工作效率 而且还影响到它的使用寿命 如果在低温下柴油机不 能起动或不能可靠地起动 不仅会降低柴油机的利用率 而且还会给使用者带来 许多不便 甚至会延误时机 造成重大损失 所以 柴油机的冷起动性能是必须 解决的问题 因此 提高柴油机冷起动的可靠性已经成为当前柴油机发展中的 重要课题之一 三 国内外研究现状三 国内外研究现状 近几年来 国内外的工作者对柴油机冷起动问题的研究取得了一定成果 成果表明 柴油机要可靠起动必须具备三个基本条件 一是燃油与空气混合成一 定数量的可燃混合气体 二是可燃混合气达到一定的温度 三是着火温度的保持 时间必须足够长 在这一理论基础上 人们提出了改善柴油机冷起动性能的多种 措施 如增大压缩比 提高进气温度 安装电热塞 火焰预热 使用缸体加热器 和油底壳加热器 采用循环水加热系统 火焰式加热器 选用低凝点柴油 采用 电控多段燃油喷射系统 提高十六烷值 采用添加剂和加入辅助燃料等 并对各 种措施的有效性进行了试验研究 四 课题要研究与解决的主要问题四 课题要研究与解决的主要问题 承德石油高等专科学校毕业设计 论文 2 本设计计划选定一种常用的柴油机进行分析改造 针对我国东北 西北 的实际情况分析影响柴油机低温起动的因素 并且分析目前常采用的低温冷起动 燃烧过程及其工作原理 通过对不同冷起动燃烧过程使用性能的分析与改进 提 出在寒冷的环境温度下应选择的来改善柴油机的低温起动的燃烧过程 五 拟采用的研究方法五 拟采用的研究方法 为了提高车用柴油机的冷起动性能 有多种辅助措施可供选择 1提高压缩比的冷起动的燃烧过程 柴油机属压燃式发动机 在低温条 件下起动时 由于进气温度 燃烧室温度较低 造成压缩终点工质的温度和压力 均较低 同时 由于起动时活塞的运动速度较低 所以导致漏气损失增加 也使 压缩终点的温度降低 从而使燃油的雾化及着火条件变差 造成柴油机冷起动困 难 因此 提高压缩终点的工质温度 减少压缩过程的漏气损失是改善柴油机冷 起动性能的根本措施 具体采用缸内机油喷射的柴油机冷起动辅助装置 2PTC 柴油机进气预热起动器 PTC 柴油机进气预热起动器主要由 PTC 进 气预热器 气门控制机构 预热时间控制器 预热启动保护开关组成 3采用低温机油 低温机油可以减少柴油机的内摩擦阻力 从而减少 起动阻力矩 提高起动转速 而使得柴油机能在较低的温度下顺利起动 4使用乙醚喷射装置 能够保证在一 40 一 0 时正常起动等 六 进度安排六 进度安排 2011 年 4 月 24 日 5 月 1 日熟悉题目 查找资料 撰写开题报告 2011 年 5 月 8 日 5 月 8 日提出研究方案 2011 年 5 月 9 日 5 月 15 日循环燃烧 低温启动过程研究 2011 年 5 月 16 日 5 月 22 日低温起动燃烧过程研究 2011 年 5 月 23 日 5 月 29 日整理数据资料 2011 年 5 月 30 日 6 月 5 日综合设计 2011 年 6 月 6 日 6 月 12 日编写设计说明说 2011 年 6 月 13 日 6 月 19 日整理资料 2011 年 6 月 20 日 6 月 24 日毕业答辩 七 参考文献七 参考文献 承德石油高等专科学校毕业设计 论文 3 李德桃 柴油机冷起动的基础研究和改善措施 北京 科学出版社 1998 蒋德明 内燃机燃烧学 黄玮 柴油发动机构造 金国栋 内燃机原理 徐延驰 陈维汉 工程热力学 北京 中国电力出版社 周云龙 洪文鹏 工程流体力学 北京 中国电力出版社 陈炳嫩 肖云魁 柴油机低温起动性能的研究 总后军事交通运输研究所 2001 罗灯明 发动机电控系统故障诊断与实训 北京 高等教育出版社 吴社强 柴油机低温冷起动方法探讨 柴油机 2003 2 郭新华 汽车构造 北京 高等教育出版社 罗涛 王忠等 采用进气火焰预热柴油机低温起动的研究 内燃机工程 2006 赵振仑 内燃机的低温起动辅助措施 小型内燃机 1990 2 22 31 杜巍 柴油机低温起动性能的研讨 内燃机 1998 5 36 39 孙树仁等 东风柴油机低温冷起动性能与低温用发动机油 汽车工艺与材 料 2005 1 王明文等 提高柴油机高原低温起动性能的辅助措施 汽车运用 2005 5 28 承德石油高等专科学校毕业设计 论文 4 二二 英语翻译英语翻译 fuel injection system Field of application The introduction of the first series production in line fuel injection pump in1927 mar ked the beginning of diesel fuel injection system manufacture at Bosch The in line fuel injection pump s main area of application is still in all sizes of commercial vehicle diesel engines stationary diesel engines locomotives and ships Injection pressures of up to approx 1350 bar are used to generate output powers of up to about 160 kW per cylinder Over the years awidevarietyofdifferentrequirements suchastheinstallationof direct injection DI engines in small delivery vans and passenger cars haveed to the development of various diesel fuel injection systems which are aligned to the requirements of a particular application Of major importance in these developments are not only the increase in specific power but also the demand for reduced fuel consumption and the call for lower noise and exhaust gas emissions Comparedtoconventionalcam drivensystems theBosch Common Rail fuel injection system for direct injection DI diesel engines provides for considerably higher flexibility in the adaptation of the injection system to the engine for instance Extensive area of application for passenger cars and light commercial vehicles with output powers of up to 30 kW cylinder as well as for heavy duty vehicles locomotives and ships with outputs of up to approx 200 kW cylinder High injection pressures of up to approx 1400 bar Variable start of injection Possibility of pilot injection main injection and post injection Matching of injection pressure to the operating mode Functions Pressure generation and fuel injection are completely decoupled from each other in the Common Rail accumulator injection system The injection pressure is generated independent of engine speed and injected fuel quantity The fuel is stored under pressure in the high pressure accumulator the Rail ready for injection The injected fuel quantity is defined by the driver and the start of injection and injection pressure are calculated by the ECU on the basis of the stored maps The ECU then triggers the solenoid valves so that the injector injection unit at each engine cylinder injects accordingly The ECU and sensor stages of such a CR fuel injection system comprise ECU Crankshaft speedsensor Camshaft speedsensor Accelerator pedal sensor Boost pressure sensor Rail pressure sensor Coolant sensor and Air mass meter Using the input signals from the above sensors the ECU registers the driver s requirements accelerator pedal setting and defines the instantaneous operating performance of the engine and the vehicle as a whole 承德石油高等专科学校毕业设计 论文 5 It processes the signals which have been generated by the sensors and which it receives via data lines On the basis of this information it can then intervene with open and closed loop controlling action at the vehicle and particularly at the engine The engine speed is measured by the crankshaft speed sensor and the camshaft speed sensor determines the firing sequence phase length The electrical signal generated across a potentiometer in the acceleratorpedal module informs the ECU about how far the driver has depressed the pedal in other words about his her torque requirement The air mass meter provides the ECU with data on the instantaneous air flow in order that combustion can be adapted so as to comply with the emissions regulations Insofar as the engine is equipped with an exhaust gas turbocharger and boost pressure control the boost pressure sensor also measures boost pressure At low outside temperatures and with the engine cold the ECU applies the data from the coolant temperature and air temperature sensors to adapt the setpoint values for start of injection post injection and further parameters to the particular operating conditions Depending upon the vehicle in question in order to comply with the increasing demands for safety and comfort further sensors and data lines provide inputs to the ECU Fig Basic functions The basic functions control the injection of the diesel fuel at the right moment in the right quantities and with the correct injection pressure They ensure that the diesel engine not only runs smoothly but also economically Auxiliary functions Auxiliary closed and open loop control functions serve to improve both the exhaust gas emission and fuel consumption figures or are used for increasing safety comfort and convenience Examples here are Exhaust Gas Recirculation EGR boost pressure control vehicle speed control cruise control and electronic immobilizer etc The CAN bus system permits the exchange of data with other electronic systems in the vehicle e g ABS and electronictransmission shiftcontrol Duringvehicleinspectioninthe workshop a diagnosis interface permits evaluation of the stored system data Injection characteristics Conventional injection characteristic With conventional injection systems using distributor and in line injection pumps fuel injection today comprises only the main injection phase without pilot and post injection phases Fig 1 On the solenoidvalve controlled distributorpumpthough developmentsareprogressingtowardsthe introduction of a pilot injection phase In conventional systems pressure generation and the provision of the injected fuel quantity are coupled to each other by a cam and a pump plunger This has the following effects upon the injection characteristics The injection pressure increases together with increasing speed and injected fuel quantity During the actual injection process the injection pressure increases and then drops again to the nozzle closing pressure at the end of injection The consequences are as follows Smaller injected fuel quantities are injected with lower pressures than larger injected fuel quantities refer to Fig 1 The peak pressure is more than double that of the mean injection pressure andIn line with the requirements for efficient combustion the rate of discharge curve is practically triangular The peak pressure is decisive for the mechanical loading of a fuel injection pump s 承德石油高等专科学校毕业设计 论文 6 components and drive On conventional fuel injection systems it is decisive for the quality of the A F mixture formation in the combustion chamber Injection characteristics with Common Rail Compared to conventional injection characteristics the following demands are made upon an ideal injection characteristic Independently of each other injected fuel quantity and injection pressure should be definable for each and every engine operating condition provides more freedom for achieving ideal A F mixture formation At the beginning of the injection process the injected fuel quantity should be as low as possible that is during the ignition lag between the start of injection and the start of combustion These requirements are complied with in the Common Rail accumulator injection system with its pilot andmain injection features Figs 2 and 4 The Common Rail system is a modular system and essentially the following components are responsible for the injection characteristic Solenoid valve controlled injectors which are screwedintothecylinderhead Pressureaccumulator rail and High pressure pump The following components also also required in order to operate the system Electronic control unit ECU Crankshaft speed sensor and Camshaft speed sensor phase sensor For passenger car systems a radial piston pump is used as the high pressure pump for pressure generation Pressure is generated independently of the injection process The speed of the high pressure pump is coupled directly to the engine speed with a non variable transmission ratio In comparison with conventional injection systems the fact that delivery is practically uniform means that not only is the Common Rail high pressure pump much smaller but also that its drive is not subject to such high pressure loading peaks The injectors are connected to the rail by short lines and essentially comprise a nozzle and a solenoid valve which is energized by the ECU to switch it on start of injection When the solenoid valve is switched off de energized injection ceases Presuming constant pressure the injected fuel quantity is directly proportional to the length of time the solenoid valve is energized It is completely independent of the engine or pump speed time controlled fuel injection The required high speed solenoid switching is achieved by using high voltages and currents This means that the solenoid valve triggering stage in the ECU must be designed accordingly The start of injection is controlled by the angle time control system of the EDC Electronic Diesel Control This uses a sensor on the crankshaft to register engine speed and a sensor on the camshaft for phase detection working cycle Pilot injection Pilot injection can be advanced by up to 90 crankshaft 90 cks referred to TDC If the start of injection occurs less than 40 cks BTDC fuel can be deposited on the surface of the piston and the cylinder walls and can lead to unwanted dilution of the lube oil With pilot injection a small amount of diesel fuel 1 4 mm3 is injected into the cylinder to precondition the combustion chamber Combustion efficiency can be improved as a result and the following effects are achieved The compression pressure is increased slightly due to pilot reaction and partial combustion this in turn leads to The main injection ignition delay being reduced and A reduction of combustion pressure rise and of the combustion pressure peaks softer combustion These effects reduce the combustion noise the fuel consumption and in many cases the exhaust gas emissions as well In the case of a rate of discharge curve without 承德石油高等专科学校毕业设计 论文 7 pilot injection Fig 3 in line with the compression only a slight flat pressure rise is evident just before TDC after which it peaks relatively sharply at the point of maximum pressure The steep pressure increase together with the sharp peak contribute considerably to the diesel engine s combustion noise As shown by the rate of discharge curve with pilot injection Fig 4 pressure inthevicinityofTDCreachesasomewhathighervalue andthe combustion pressure increase is less rapid Since it reduces the ignition delay pilot injection makes an indirect contribution to the generation of engine torque The specific fuel consumption can increase or decrease as a function of the start of main injection and the time between the pilot and main injection sequences Main injection The energy for the engine s output work comes from the main injection sequence This means that essentially the main injection is responsible for the development of the engine s torque With the Common Rail accumulator fuel injection system the injection pressure remains practically constant throughout the whole of the injection process Secondary injection With certain versions of NOX catalytic converter secondary injection can be applied for NOX combustion reduction It follows the main injection process and is timed to take place during the expansion or exhaust cycle up to 200 cks after TDC Secondary injection introduces a precisely metered quantity of fuel to the exhaust gas In contrast to the pilot and main injection processes the injected fuel does not combust but instead vaporises due to the residual heat in the exhaust gas During the exhaust cycle the resulting mixture of exhaust gas and fuel is forced out through the exhaust valves and into the exhaust gas system Part of the fuel though is returned for combustion via the EGR system and has the same effects as very advanced pilot injection Provided suitable NOX catalytic converters arefitted these utilise the fuel in the exhaust gas as a reduction agent to lower the NOX content in the exhaust gas Since very late secondary injection leads to dilution of the engine lube oil it must be approved by the engine manufacture 承德石油高等专科学校毕业设计 论文 8 译文 译文 燃油喷射系统燃油喷射系统 应用的范围应用的范围 第一个系列的介绍燃油喷射泵是 1927 年 生产在线标志着美国开始的柴油 机燃油喷射系统生产博世 燃油喷射泵的在线应用程序仍然是主要的区域在所有 大小的商业中 例如柴油发动机 静止车辆柴油机 机车车辆和船舶 注射压力 上升到大约 1350bar 被用来产生输出的势力 大约 160 千瓦 气缸 在过去的几年 里 各种各样的不同的要求 如安装 涤 发动机在小送货车辆和客车的发展上 例 如各类柴油燃油喷射系统 这种系统排列到某一特定的应用需求 在这些发展中 占有十分重要的不仅是在特定的力量增加的需求 但也降低了燃料消耗 并呼吁噪 音低 尾气排放 相比传统的凸轮驱动燃油泵系统 博世 共轨燃油喷射系统柴 油机提供高多采用灵活的适应性的喷射系统与发动机 比如 广泛的地区的应用 轿车和轻型商用车辆具有输出大国 30 千瓦 气缸的基础 也为重型车辆 铁路机 车 船和输出的大约 200 万千瓦 缸 高注射压力上升到大约 1400 酒吧 变量 开始的可能性注射 注塑成型 主要注射 飞行员和后期注射 匹配的注射压 力对操作模式 功能功能 一代和燃油喷射压力是完全解耦 从彼此的 蓄电池 共轨喷油系统 独立 的注射压力产生的发动机转速 喷油量 燃料在压缩状态下贮存于高压蓄能器 轨道 准备注射液的热原检查 注油量主要是由司机 开始 注塑 喷油压力的 计算都由电子控制单元 ECU 控制的基础上 储存的地图 电子控制单元 ECU 控 制然后触发电磁阀门使喷油器 注塑单位 在每个发动机气缸注入了相应的解决 方法 电子控制单元 ECU 控制 传感器的各阶段的工作这样一个铬燃油喷射系 统包括 控制单元 ECU 控制 凸轮轴加速传感器 曲轴传感器 加速器踏板传 感器 导轨压力传感器 增压传感器和冷却液气团进行测量仪表 应用输入信 号从上述传感器 电子控制单元 ECU 控制寄存器司机的要求 加速踏板设置 的 基础上 界定了发动机的瞬态运行性能与车辆作为一个整体 它处理的信号已经 生成的传感器 并通过数据传输线上收到 在此基础上的信息 然后就可以介入的 开放和闭环控制作用在汽车 尤其是在引擎 柴油机的转速传感器测量的机轴加 速传感器 并决定了机轴加速点火顺序 相长 产生的电子信号电位器在加速器踏 板穿过一个模块的 ECU 如何通知司机已经降低远踏板 换句话说约他 她 的扭矩 要求 电子控制单元 ECU 控制的气团进行测量仪表上的数据提供瞬时空气流动 以便燃烧可改动以符合排放法规 制定本办法 因此在发动机 配备了尾气增压器 和增压压力传感器控制 来改善增压压力 在较低的温度和引擎外面冷 电子控制 单元 ECU 控制应用的数据和温度传感器 冷却剂温度适应世界设定的价值观为 起动的注塑 岗位注射 并进一步的参数给特定的操作条件 根据车辆的问题 为 承德石油高等专科学校毕业设计 论文 9 了符合需求日益增长的安全性和舒适性 进一步传感器和数据输入线提供电子控 制单元 ECU 控制 基本功能基本功能 其基本职能控制注射的柴油燃料 在合适的时机以适当的数量 并按照正确的 注射压力 他们确保柴油机不仅运行平稳 而且在经济上 辅助功能辅助功能 辅助关闭和开环控制功能服务于促进企业的排气 瓦斯涌出和燃油消耗数据 或用于增加安全 舒适 方便 这里有尾气例子 增加压力排气再循环 控制 车 辆速度控制 巡航控制系统 和电子防盗控制系统等 CAN 总线的系统允许交换 数据与其他电子系统在车辆 例句 ABS 和电子传送装置变化的控制 在车辆检 查在车间内 诊断界面允许存储系统评价的数据 喷射特性喷射特性 常规射出特征常规射出特征 与常规的喷射系统 利用分销和在线喷油泵 燃油喷射包括现在只有主要注射 阶段 在没有飞行员和邮递注册在电磁阀控制泵 发展经销商正在增进虽然对 引入一种飞行员注射阶段 在传统的系统 压增长并提供注射的油量是耦合的彼 此一个凸轮和泵柱塞 这有如下特点 在注射效果 注塑压力的增加