Improvement on On-line Ferrograph Image Identification

A newly developed on-line visual ferrograph（OLVF） gives a new way for engine wear state monitoring. However, the reliability of on-line wear debris image processing is challenged in both monitoring ship engines and the Caterpillar bench test, which weren＇t reported in previous studies. Two problems were encountered in monitoring engines and processing images. First, small wear debris becomes hard to be identified from the image background after monitoring for a period of time. Second, the identification accuracy for wear debris is greatly reduced by background noise because of oil getting dark after nmning a period of time. Therefore, the methods adopted in image processing are examined. Two main reasons for the problems in wear debris identification are generalized as follows. Generally, the binary threshold was determined by global image pixels, and was easily affected by the non-objective zone in the image. The boundary of the objective zone in the binary image was misrecognized because of oil color becoming lighter during monitoring. Accordingly, improvements were made as follows. The objective zone in a global binary image was identified by scanning a column of pixels, and then a secondary binary process confined in the objective zone was carried out to identify small wear debris. Linear filtering with a specific template was used to depress noise in a binary image, and then a low-pass filtering was performed to eliminate the residual noise. Furthermore, the morphology parameters of single wear debris were extracted by separating each wear debris by a gray stack, and two indexes, WRWR （relative wear rate） and WRWS （relative wear severity）, were proposed for wear description. New indexes were provided for on-line monitoring of engines.

Four basic laws in design science

A point on the distinction between design and science is given and the connotanons of aeslgn science are discussed in the paper. Design should be understood as the first step of all human＇ s purposeful activity, which is a daily behavior for everyone. Four laws are summarized, which describe the basic patterns of design and are the constituents of design science. They are the law of design based on existed knowledge, law of in- completeness of design knowledge, law of design centered on new knowledge acquirement and law of competi- tiveness of design knowledge. The four basic laws show the knowledge essence of design. To enrich the existed knowledge, to make it convenient to be used, to teach designers with high intuition and inspiration in picking useful elements of existed knowledge and shaping competitive ideas and to have strong new knowledge acquire- ment facility are the basic conditions of good designs. Study of design science will promote the structure of tra- ditional engineering education. An important conclusion is derived that there will be no successful innovation without good design.

逆向教学设计法在项目式教学中的应用--以上海交通大学“工程学导论”为例

新工科的实施核心之一在于在实践中落实以成果为导向的工程教育新模式。本文以逆向教学设计理论为指导,以上海交通大学机械与动力工程学院"工程学导论"。为平台,从设计层级化的学习目标、开展多样化的学习活动、运用多元化的评价反馈策略三方面出发,构建基于项目式教学的系统化课程设置流程。本研究是一项在系统教学理论指导下、在工程教育实践中应用基于项目式教学法,落实以成果为导向的实践案例。通过案例的演示,本研究对工程教育过程中如何明确教学目标、合理设计教学活动、优化教学方法以及如何有效进行课程评价等各方面提出了有效建议。

Blow-by and tribological performance of piston ring pack during cold start and warm idle operations

To reduce the fuel consumption of internal combustion engines, more attention has been paid to the tribological performance of the piston ring pack during the cold start and idle operations. In this research, a numerical model considering the cylinder liner deformation and the piston ring conformability is developed to predict the blow-by, lubrication, friction and wear of the piston ring pack under different operating conditions. The gas flow rate, inter-ring gas pressures, minimum oil film thickness, frictional force and wear load during cold start are calculated and compared with those during warm idle operating conditions. The results show that cylinder liner deformation and piston ring conformability together obviously affect blow-by and other tribological performance. Meanwhile, it is found that friction loss is larger during cold start than during warm idle operating conditions. However, the wear process is more severe during warm idle operation than during cold start. From this research, the blow-by and tribological performance of the piston ring pack during cold start and warm idle operations are understood more deeply.

Functional knowledge integration of the design process

Functional knowledge integration is the initial and core phase of a design process. It is the key phase to ensure that the functional requirement of the design product can be appropriately complied with, and its result is also the rudiment of the subsequent detailed design work. If this important phase can be supported by an increasingly distributed resource environment, and be automated such that its completion requires less manual work, the efficiency of the design process would be largely improved and its ability to promote innovation would be enhanced. Therefore, this study involved a detailed analysis of the functional knowledge integration of the design process, as well as the proposal of a corresponding running model. Based on the model, a computational algorithm and an evaluating method were established to automate functional knowledge integration. A corresponding computer program was developed to prove the feasibility of this approach, and it was used to design a solarpowered wiper blade.