Development of a Calibration and Monitoring System for GD-1 High Pressure Common Rail Diesel Engine

Based on CAN calibration protocol, a new calibration and monitoring system was developed for the GD-1 high pressure common rail diesel engine. CAN driver block, monitoring program and calibration program for this system were designed respectively. The inquiry mode was used in the monitoring program and the interrupt mode was used in calibration program. The calibration program was designed in structural programming model. This system provides a reliable, accurate and quick CAN bus between ECU and PC, with baud rate up to 500Kbit/s. The implementation of the compatible and universal CAN calibration protocol makes it easy to displace the system and its function modules. It also provides friendly, compatible and flexible calibration interface, and the functions of online calibration and real-time monitoring. This system was successfully used in a GD-1 high pressure common rail diesel engine and the engine performance and exhaust emissions were significantly improved.

Research and Development of a New Calibration Tool for Electronically Controlled Engine Based on KWP2000

Today’s vehicles use electronic control units(ECU) to control engine/transmission, body and other amenities. All the vehicle performance depends on a lot of physical values and influence factors. This leads to a large number of control and regulation parameters in the ECU software. The ultimate objective of calibration work is the optimum determination of these parameters. Qualitatively excellent results can only be achieved in a shorter time by using a highly efficient calibration system. This paper provided an overview of a new calibration tool based on KWP2000 and gave an example calibration with this tool.

Analysis and Calibration of Internal Flow Force of EjectorPowered Engine Simulator System in Wind Tunnels

The ejector-powered engine simulator(EPES)system is an important piece of equipment in conducting an influence test of the intake and jet flow in low-speed wind tunnels.In this work,through the analysis of the structure and principle of EPES,three parts of the internal flow force were obtained,namely,the additional resistance before the inlet,the internal flow force in the inlet and the thrust produced by the ejector.On the assumption of one-dimensional isentropic adiabatic flow,the theoretical formulae for calculating the forces were derived according to the measured total pressure,static pressure and total temperature of the internal flow section.Subsequently,a calibration tank was used to calibrate the EPES system.On the basis of the characteristics of the EPES system,the process and method of its calibration were designed in detail,and the model installation interface of the calibration tank was reformed.By applying this method,the repeatability accuracy of the inlet flow rate calibration coefficient was less than0.05%,whereas that of the exhaust flow rate and velocity was less than 0.1%.Upon the application of the calibration coefficients to the correction of the wind tunnel experiment data,the results showed good agreement with the numerical simulation results in terms of regularity and magnitude before stall,which validates the reasonableness and feasibility of the calibration method.Analysis of the calibration data also demonstrated the consistency in the variation law and trend between the theoretical calculation and actual measurement of internal flow force,further reflecting the rationality and feasibility of the theoretical calculation.Nevertheless,the numerical difference was large and further widened with a higher ejection flow rate mainly because of the accuracy of flow measurement and the inhomogeneity of internal flow.The thrust deflection angle of EPES is an important factor in correcting this issue.In particular,the thrust deflection angle becomes larger with small ejection flow and becomes smaller with an increase in flow rate,essentially exhibiting a general change of less than 10°.

Novel adaptive laser scanning sensor for reverse engineering measurement

In this paper,a series of new techniques are used to optimize typical laser scanning sensor.The integrated prototype is compared with traditional approach to demonstrate the much improved performance.In the research and development,camera calibration is achieved by extracting characteristic points of the laser plane,so that the calibra- tion efficiency is improved significantly.With feedback control of its intensity,the laser is automatically adjusted for different material.A modified algorithm is presented to improve the accuracy of laser stripe extraction.The fusion of data extracted from left and right camera is completed with re-sampling technique.The scanner is integrated with a robot arm and some other machinery for on-line measurement and inspection,which provides a flexible measurement tool for reverse engineering.

Parameter Identifiability and Parameter Estimation of a Diesel Engine Combustion Model

In this paper an original method based on the link between a piecewise identifiability analysis and a piecewise numerical estimation is presented for estimating parameters of a phenomenological diesel engine combustion model. This model is used for design, validation and pre-tuning of engine control laws. A cascade algebro-differential elimination method is used for studying identifiability. This investigation is done by using input-output-parameter relationship. Then these relations are transformed by using iterated integration. They are combined with an original numerical derivative estimation based on distribution theory which gives explicit point-wise derivative?estimation formulas for each given order. Then new approximate relations, linking block of parameters and outputs (without derivative) are obtained. These relations are linear relatively to the blocks of parameters and yield a first estimation of parameters which is used as initial guess for a local optimization method (least square method and a local search genetic algorithm).

活动门试验中土压力盒标定方法

为确保活动门试验结果的准确性,根据试验填土深度的不同,对一批相同型号的电阻式土压力盒进行了垂直方向上的分级加载和卸载标定,并考虑标定装置内壁摩擦力影响,修正了作用在土压力盒上的有效加载和卸载应力。通过对加卸载过程进行离散元模拟,证明有效加载和卸应力修正方法较为合理。标定试验结果表明,加载过程中微应变量-有效应力曲线呈线性变化,可使用线性函数拟合;卸载过程中微应变量-有效应力曲线存在明显的滞后现象,且滞后程度随有效加载应力的增大而增大,可使用单指数曲线拟合。标定土压力盒后,开展了填土试验,结果表明土压力盒不宜在压力过小或填土深度过小时使用。

小惯性热电偶动态校准及频域分析

发动机进气温度畸变影响发动机的稳定性,通常使用小惯性热电偶来测量其快速变化的气流温度。为准确全面获取小惯性热电偶的动态特性,提出了一种小惯性热电偶的动态特性校准及评价方法,并阐述了小惯性热电偶动态校准装置的构建、校准试验以及频域分析。采用脉冲激光器与校准风洞相结合的小惯性热电偶动态校准方法,通过幅频特性和相频特性分析,拓展了小惯性热电偶的动态特性评价方法。用该校准方法对小惯性热电偶进行动态校准,结果A类相对不确定度最大值由7.2%减小到2.4%,可应用于30 ms以下量级快响应温度传感器的动态校准,为发动机进气温度畸变等高频动态温度测量提供技术参考。

探测器阵列高精度二维标定平台控制系统设计

为了实现快速、高精度探测器阵列标定,对探测器阵列高精度二维标定平台控制系统进行了研究,设计了采用单片机控制步进电机加编码器的闭环位移控制系统。介绍了该平台的标定原理和硬、软件控制系统设计,并对控制PID算法进行了研究,最后搭建了标定系统对控制系统进行综合测试。实验结果表明该控制系统有良好的控制能力,平台在600 mm×600 mm的有效行程内定位精度可达-11~12μm,十次单点测试数据变异系数为0.13%,连续模式下平均测量误差为1.65%。该平台设计满足探测器阵列的标定要求,为探测器阵列标定提供了一种有效手段。

在用车排放颗粒测量仪器标定及实验研究

目的:在用车尾气排放颗粒物数目含量检测技术和设备国产化。方法:基于凝结核增长计数原理,采用自稀释结构,并调整温度设置,研发了纳米级细颗粒物计数仪器,并在洁净间进行了标定实验,同时,基于标定完成的自研CPC仪器对在用车排放尾气颗粒物数目含量进行了实地测量。结果:在使用自稀释结构,采样温度为6~50℃下,自研仪器的D50达到了9.2 nm,满足机动车D50为23±1 nm的检测要求,仪器瞬态响应误差为9.53%,检测范围在0~5×10^(4)个/mL,满足仪器误差指标。此外,针对在用车排放尾气的实地测量结果表明,自研CPC具有较好的辨识能力,可以准确地捕捉到不同量级的颗粒物数目含量变化趋势,且自研CPC与TSI CPC的峰值相对误差变化均低于10%。结论:研制的仪器达到机动车尾气检测标准,且仪器检测范围内一致性较高。

柴油机活塞环润滑油膜厚度超声波测量方法研究

活塞组件-缸套摩擦副位置处良好润滑状态能够保障柴油机的稳定运行,润滑油膜厚度能够对其润滑状态进行判断。因此本文以润滑油膜厚度为测量目标,基于等效弹簧模型超声波测量原理对活塞环位置处润滑油膜厚度开展实验研究。搭建了润滑油膜厚度超声测量实验平台,通过实验证实了超声方法的测量能力。构建了柴油机活塞环润滑油膜厚度测量方案,设计并搭建了活塞环润滑油膜厚度动态测量系统,对不同转速下的润滑油膜厚度进行了实验测量。通过对实验数据进行处理,在活塞环处测得了2.2~3.9μm的润滑油膜厚度,并且随转速增加,油膜厚度呈现增大趋势,证实了该方法的可行性。

海上工程船施工定位精度提高的方法研究

某石油企业的海上工程船在使用过程中存在定位精度不足的现象,平均误差达到2.55m,影响了海上作业的效率,导致施工船需要频繁调整位置。为了解决该问题,研究过程建立了工程船动力定位的数学模型,分析了相应的定位原理,系统性地排查可能引起定位偏差的原因,最终确定误差主因为电罗经的安装角度。根据天文观测的原理,使用全站仪修正电罗经的安装角度,经过实测,工程船的平均定位误差下降至0.5m,达到了预期效果。

面向碳减排的城市交通微观仿真模型优化研究

为评估交通管控策略的环境效益,提出有效融合微观交通仿真模型和微观车辆排放模型的方法。利用VISSIM平台构建案例微观交通仿真模型,提出基于轨迹数据的不同速度区间的加减速特征,应用K-means聚类方法划分4种驾驶行为,通过驾驶特性标定仿真模型全局参数,描述了参数总敏感度以及参数之间相互作用的敏感度。利用DBSCAN(density-based spatial clustering of applications with noise)聚类分析并标定局部参数值,优化了参数标定流程。计算仿真轨迹工况,本地化MOVES(motor vehicle emission simulator)微观排放模型,得到交叉口不同流向和不同驾驶行为下的HC、CO、NO_(x)、CO_(2)排放。研究表明:仿真模型优化效果显著,所提方法可精确识别高排放的空间位置,解析排放与驾驶行为之间的联系。应用DBSCAN聚类分析参数寻优值有助于实现自动化标定流程,全局参数标定将速度分布χ^(2)误差由0.6327降至0.1306,加速度分布χ^(2)误差由0.1441降至0.0528,对于环境视角下仿真模型构建至关重要。

高静压压差检定装置的建立与测量不确定度评定

差压类压力测试仪表在航空等领域中有着广泛应用,基于现场工作条件等因素,差压仪表的准确性可能随着时间的推移发生变化,在高静压检测下静压性能差的差压变送器结果会产生很大的误差,如果前期未对差压变送器开展高静压的静压差压检测,则检定的可信度就会存在系列性的疑问。介绍了高静压压差检定装置的特性,并通过基准级计量标准分析该装置测量不确定度,为航空发动机测试数据的准确可靠提供有力的技术支撑。

基于流场测试的航空发动机试车台校准研究

试车台试验是航空发动机型号研制、批产交付、技术研究的重要手段,试车台测试的准确性直接影响航空发动机的性能评估结果。采用流场测试的方法,测量航空发动机试车时的流场分布,并计算试车台不同工况下航空发动机的附加阻力变化情况,在计算结果的基础上对推力测量值进行修正。通过计算可知,进气流场分布整体较为均匀,进气流速不均匀度低于35%,最大进气流速不均匀度为32.84%。核心区域为航空发动机的主要进气区域,最大进气流速不均匀度为23.80%。试车台附加阻力与推力测量值为线性关系,进气冲量阻力占航空发动机推力的2.04%左右。

基于预测模型的柴油机排气热管理标定方法研究

基于一款六缸重型柴油机,根据台架试验数据中排气温度确定热管理区域,采用空间填充法进行试验设计,并根据设计方法进行台架试验,搭建基于高斯过程回归的预测模型,以发动机NOx和Soot排放为约束条件,以排温为目标求解出燃油消耗率最低的控制参数,生成控制参数的MAP用于后期台架试验。通过台架试验结果在热管理区域显示,NOx和Soot排放满足要求,油耗升高率在合理范围内,在升温模式下稳态试验排气平均温度提升40℃左右,瞬态试验排气平均温度提升30℃左右,且WHTC瞬态循环时间缩短。

整车空气量校准标定指导

在新排放法规执行后,柴油机市场的竞争日渐强化,要求主机厂能够快速适应市场变化,缩短标定周期,提升效率。针对目前柴油机适配情形,一种发动机机型通常会适配多个整车机型,整车端进气系统的差异会造成整车排放性能变化,这是当前存在的一个重要问题。本文研究由于进气系统不同造成的空气量差异问题,提出应对解决方案,以此帮助标定工程师快速了解标定过程中整车空气量校准的重要性,对整车标定工作有一定的指导意义。

国六排放重型天然气发动机湿度传感器的应用

湿度传感器在发动机控制系统中已经得到广泛应用,进气湿度传感器作为国六天然气发动机各种性能的关键电控零部件,对天然气发动机控制系统有重要作用。探讨湿度传感器在天然气发动机上的应用,并在台架上进行验证。结果表明,通过湿度传感器有效地监测进气口的湿度,以便发动机控制器调整燃烧参数,可以使发动机实现良好的经济性和较低的排放。

涡扇发动机吞雹试验

为研究某型涡扇发动机吞雹能力,按照CCAR-33R2标准33.78(a)条开展了整机吞雹试验方法研究及验证。梳理了试验流程,确定了试验条件,对发动机、试车台等进行了分析,开展了防护装置、摄影装置、投射装置设计,并对冰雹的制作方法进行了研究。通过投射装置实现了冰雹向发动机的投射,同时设计了试验前的校靶试验和空炮试验,通过校靶试验保证了投射的速度和准确性,通过空炮试验测试了投射装置对发动机进气的影响,又通过高速摄影验证了冰雹投射的速度和撞击位置的准确性。发动机吞入冰雹过程中推力出现短时减小,随后恢复了稳定工作,吞雹后发动机排气温度下降约2%~3%,转差变化约-0.6%~0.2%,推力下降约0.1%~1.6%;其余参数无明显变化,通过低压测点时域信号采集了风扇部分的冲击响应;试验后分解检查5片风扇叶片进气边变形,未出现掉块情况,未发现可能危及飞行安全的结构损坏,验证了某型涡扇发动机的吞雹适航符合性。

瓦斯发动机气源波动适应性分析及改进

为解决低浓度瓦斯气源波动造成的发动机功率波动、分闸、放炮、停机等故障,进一步提高瓦斯发动机气源波动适应性,以某12缸低浓度瓦斯发动机配套机组为研究对象,分析瓦斯气源波动对发动机性能的影响;增加故障降载功能对发动机控制系统进行优化,并进行试验验证。结果表明:瓦斯中甲烷的体积分数变化率低于0.1%/min时,发动机功率波动不大,控制系统能够通过闭环控制使发动机恢复到稳定状态;瓦斯中甲烷的体积分数变化率大于1%/s时,发动机运行在额定功率的90%、50%工况时,功率波动较大,试验过程中伴有放炮现象;在瓦斯发动机控制系统中增加故障降载功能及进行参数标定后,当气源剧烈波动时,控制系统及时降低发动机功率、快速修正瓦斯流量,使发动机安全平稳度过瓦斯波动期,增强发动机瓦斯气源波动适应性。

航空发动机小扰动叶型受感部设计及试验研究

对航空发动机级间性能参数测试的小扰动叶型受感部进行数值模拟研究和校准试验研究。数值模拟研究结果表明,带B型整流罩的叶型受感部对流场的影响更小;校准试验研究表明,B型叶型受感部的总压特性较好,不敏感角范围为-30°~10°,总压测量误差绝对值不大于0.1%。根据数值模拟和校准试验研究结果,寻求某型航空发动机小扰动叶型受感部的最优设计方案,并在该型发动机整机全流程参数测量试验中进行试验应用,试验结果为该型发动机的性能验证、改进、改型提供了重要的技术支撑。