Year 13 CIE Engineering: Case Study Practical Drill | Year 13 CIE 工程：案例分析实战演练

📚 Year 13 CIE Engineering: Case Study Practical Drill | Year 13 CIE 工程：案例分析实战演练

Case studies form the backbone of CIE A Level Engineering assessment, challenging you to think like a professional engineer under exam conditions. This article walks you through a complete case study, from initial brief to final recommendations, equipping you with a structured framework you can adapt to any scenario. We will work on a fictitious but realistic design problem: a portable solar-powered charger for off-grid communities, mirroring the depth and breadth expected in your examinations.

案例研究是 CIE A Level 工程评估的核心，要求你在考试环境下像专业工程师一样思考。本文带你走通一个完整的案例研究，从最初简报到最后建议，为你提供一个可以适配任何情景的结构化框架。我们将围绕一个虚构但真实的设计问题展开：为离网社区设计一款便携式太阳能充电器，体现考试中所期望的深度与广度。

1. Understanding the Case Study Brief | 理解案例研究简报

Start by dissecting the brief with a highlighter. Our imaginary client, GreenCharge Ltd, seeks a portable solar charger for mobile devices aimed at rural households in sub-Saharan Africa. The explicit design requirements are: total mass under 500 g, foldable solar panel output of at least 5 W under standard test conditions, ruggedness to survive drops from 1.5 m, IPX4 water resistance, and a manufacturing cost below £20 per unit when produced in batches of 1000. You are also told to consider local assembly and maintenance.

先用荧光笔仔细拆解简报。我们的虚拟客户 GreenCharge Ltd 要求设计一款针对撒哈拉以南非洲农村家庭的便携式太阳能手机充电器。显性设计要求为：总质量低于 500 g，标准测试条件下可折叠太阳能电池板输出不低于 5 W，坚固到能承受 1.5 m 跌落，IPX4 防水等级，千件批量生产成本低于 20 英镑。你还被告知要考虑本地组装与维护。

Beyond these explicit demands, tease out the implicit requirements that often carry equal weight. The charger will operate in high UV, dust and heat, so materials must resist photodegradation and sand abrasion. Users may have limited technical literacy, so the interface must be intuitive – a single LED indicator and a mistake-proof USB socket. Ethical sourcing of lithium cells and recyclability to avoid e-waste are likely unspoken criteria a responsible engineer must address.

除这些显性需求外，还要挖掘往往同等重要的隐性需求。充电器将在强紫外线、沙尘和高温下工作，因此材料必须抵御光降解和砂粒磨损。用户技术素养可能有限，所以接口必须直观——单一 LED 指示灯和防误插 USB 插口。锂电池的道德采购以及可回收性以避免电子垃圾，是负责任工程师必须应对的隐性标准。

2. Identifying Stakeholder Needs and Constraints | 识别利益相关者需求与约束

Map all stakeholders: end-users (families, small business owners), local retailers, the NGO distributing the units, assembly workers in the local micro-factory, and GreenCharge's investors. Each group has distinct priorities. Users demand reliability and long battery life; retailers want distinctive, stackable packaging; the NGO cares about durability and minimal environmental footprint; workers need simple, safe assembly steps; investors watch the bill of materials and potential for scaling to other markets.

梳理所有利益相关者：终端用户（家庭、小商贩）、当地零售商、分发设备的非政府组织、本地微型工厂的装配工以及 GreenCharge 的投资者。每一方的优先级各不相同。用户要求可靠性和长续航；零售商想要醒目、可堆叠的包装；非政府组织关心耐用性和最小环境足迹；工人需要简单、安全的装配步骤；投资者关注物料清单和向其他市场扩展的潜力。

Constraints tighten the design space. The £20 cost ceiling limits component choices; local manufacturing rules out complex surface-mount soldering; a lack of refrigeration in the supply chain prevents use of certain adhesives. Regulatory constraints include RoHS compliance and IEC 62133 for battery safety. Build a simple constraints-and-criteria table early to avoid chasing infeasible ideas.

约束条件收紧了设计空间。20 英镑成本上限限制了元器件选型；本地制造排除了复杂的表面贴装焊接；供应链中缺乏冷藏条件阻止了某些粘合剂的使用。法规约束包括 RoHS 合规和电池安全的 IEC 62133 标准。尽早建立一张简单的约束与标准表，避免追逐不可行的方案。

3. Generating Design Concepts | 创建设计概念

Diverge before you converge. Sketch at least three distinct concepts. Concept A: 'Clamshell' – two rigid mono-Si panels hinged together like a book, with an integrated 18650 battery and buck converter in the spine, closing to a tough plastic case. Concept B: 'Roll Mat' – a flexible thin-film CIGS sheet that rolls into a cylinder, with a separate matchbox-sized power module connected by a flat cable. Concept C: 'Satchel' – a shoulder bag with amorphous silicon panels sewn into the flap, containing a power bank pouch inside.

发散之后再收敛。至少勾画三个不同概念。概念 A：“翻盖式”——两片刚性单晶硅面板像书本一样铰接，书脊内集成 18650 电池和降压转换器，合拢后为坚固的塑料外壳。概念 B：“卷席式”——可卷曲的柔性薄膜 CIGS 薄片，卷成圆筒状，通过扁平电缆连接一个火柴盒大小的独立电源模块。概念 C：“邮差包”——一个肩袋，翻盖上缝入非晶硅电池板，内部有充电宝口袋。

Decompose each concept by function: energy capture, power regulation, energy storage, mechanical protection, and user interface. Use a morphological chart to mix and match promising sub-solutions. For example, the clamshell's panel mounting could be borrowed for a hybrid Concept D, but for this exercise we stick to evaluating the three original ideas.

按功能分解每个概念：能量捕获、功率调节、能量存储、机械防护和用户界面。使用形态学图表混合匹配有前景的子方案。例如，翻盖概念的面板安装方式可借用于一个混合概念 D，但在本次练习中我们只评估三个原始构想。

广告 / Sponsored

4. Evaluation and Selection Using a Decision Matrix | 使用决策矩阵进行评估与选择

Construct a weighted decision matrix using the key criteria extracted from the brief. Assign weights from 1 (least important) to 5 (most important): cost (weight 5), ease of local manufacture (4), durability (4), mass (3), waterproofing (3), user experience (3), and scalability (2). Score each concept from 1 to 5 against each criterion.

利用从简报中提取的关键标准构建加权决策矩阵。为各标准分配权重 1（最不重要）到 5（最重要）：成本（权重 5）、本地制造便捷度（4）、耐久性（4）、质量（3）、防水性（3）、用户体验（3）和可扩展性（2）。针对每项标准对每个概念进行 1 到 5 评分。

Concept A 'Clamshell' scores decisively highest, primarily because it exploits readily available rigid solar cells and a simple injection-moulded housing that can be produced with low-cost tooling. It also offers excellent protection when closed. We therefore select Concept A as the basis for detailed design.

概念 A “翻盖式”得分明显最高，主要是因为它利用了容易获得的刚性太阳能电池和简单的注塑外壳，可用低成本模具生产。合上时还能提供出色的防护。因此我们选择概念 A 作为详细设计的基础。

5. Material Selection for the Chosen Design | 所选设计的材料选择

Material choice must balance cost, mechanical properties, UV stability and manufacturability. For the housing, consider ABS (low cost, good impact resistance but poor UV resistance unless stabilised) and polycarbonate (PC, better inherent UV resistance but ~30% more expensive). The hinges could be designed as living hinges in polypropylene (PP) if integral to the housing, or discrete stainless steel hinges for longevity. Solar cell encapsulation will use EVA (ethylene vinyl acetate) with a PET backsheet, a proven low-cost photovoltaic laminate.

材料选择必须平衡成本、机械性能、紫外线稳定性和可制造性。外壳方面，考虑 ABS（低成本、抗冲击性好但除非添加稳定剂否则耐紫外线差）和聚碳酸酯（PC，固有耐紫外线性更好，但价格贵约 30%）。铰链若与外壳一体可设计为聚丙烯（PP）活动铰链，或采用分体不锈钢铰链以提高寿命。太阳能电池封装将采用 EVA（乙烯-醋酸乙烯酯）加 PET 背板，这是一种经过验证的低成本光伏层压方案。

Component	Candidate Materials	Selected	Justification
Outer housing	ABS, PC, PP	UV-stabilised PC	Better outdoor life; still within budget
Hinge	PP living hinge, SS 304	SS 304 pin hinge	Withstands >10,000 cycles
Solar encapsulant	广告 / Sponsored NEW IB Prepared Biology Print & Digital Book 牛津IBDP国际文凭课程 I… 生物 备考教辅 · 正版现货 · 学习备考通用 查看详情 / View on Taobao 广告 / Sponsored 英文原版 Collins International Lower Secondary Computing 柯林斯国际初… 计算机 备考教辅 · 正版现货 · 学习备考通用 查看详情 / View on Taobao 更多咨询请联系16621398022（同微信） 备考资讯每日更新，关注不错过 考纲变化 · 科目分析 · 学习方法 在微信里长按二维码识别关注 或截图后用「扫一扫 → 相册」选择本图 公众号：tutorhao