Week 1 - Introduction

Introduction

Engineering design is defined as a technology, not a science. There are many engineering design processes as there are many duties of a Design Engineer.

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Assignment(s)

Assignment 1 - The Design of a Battery for Hybrid/Electric Cars

Lecture Material

• Chapter 1 of Engineering Design Principles: Introduction to Engineering Design

Introduction to Engineering Design

In the study of science we seek to develop theories that explain natural phenomena. These scientific principles, which are self-evident in the natural sciences, are also employed in the engineering sciences. Engineering science subjects such as thermodynamics, mechanics and materials science are generally based on established scientific principles like the first and second laws of thermodynamics, Newton's laws, and atomic and molecular theories of matter respectively.

Engineering design is quite different since theories and hypotheses cannot be developed or tested by laboratory experiments. Engineering design involves much broader issues including the consideration of people and organizations. It must therefore be regarded as a technology. Technology is defined as the application of scientific knowledge to the practical aims of human life or, as it is sometimes phrased, to the change and manipulation of the human environment. This is particularly so since no single absolute answer can be found for any problem which involves both design decisions and compromise, since almost inevitably design parameters are contradictory.

Having established that engineering design is a technology it is necessary to present a definition. The dictionary definition of design is often "to fashion after a plan", which tells us very little about the way of working that we call engineering design. Engineering design is:

• the total activity necessary to establish and define solutions to problems not solved before, or
• new solutions to problems which have previously been solved in a different way.
• The engineering designer uses intellectual ability to apply scientific knowledge and
• ensures the product satisfies an agreed market need and product design specification whilst
• permitting manufacture by the optimum method.
• The design activity is not complete until the resulting product is in use providing an acceptable level of performance and with clearly identified methods of disposal.

In order to increase our understanding of design it is helpful to extend this definition and to identify and highlight the main characteristics of engineering design:

• Trans-disciplinary
• Highly complex
• Iterative.

Question: In the design and construction of a intelligent vacuum cleaner, which engineering displines are involved?
Toggle Answer Answer: Software engineering with AI, electrical engineering, mechanical engineering, physics (optics, sensing).

Most engineering design is now a trans-disciplinary team effort and the distinctions between the traditional disciplines, mechanical, electrical, electronic, civil and even chemical engineers are becoming blurred. Relatively new areas of engineering specialization, such as control and software engineering and artificial intelligence should be added to this list.

Consider for example automobiles, which not so very long ago were the sole province of mechanical engineers. Complex engine management systems, anti-lock braking systems, active suspension systems, four-wheel steering, air bags, and automatic seat belt tensioning are just some of the new developments. These systems are highly complex and require input from many different kinds of engineers for their optimum design.

The main components in the general layout are:

1. Front wheel sensor
2. Front pulse wheel
3. Hydraulic modulator
4. Control unit
5. Rear wheel sensor
6. Rear pulse wheel
7. Indicator lamp
8. Brake tubes.

1. Battery
2. Ignition switch
3. Alternator
4. Fuse
5. Distribution coil
6. Brake switch
7. Speedometer
8. Charging lamp
9. Indicator lamp
10. Control unit
11. Hydraulic modification
12. Surge protection unit
13. Speedometer converter unit
14. Sensor - left front
15. Sensor - right front
16. ABS Fuse box
17. Sensor - rear wheels.

Although this can vary in detail, in general an engineering designer must be capable of dealing with the following:

• The production of practical design solutions starting from a limited definition of requirements taking into account many factors.
• The production of design schemes, analysis, manufacturing drawings and related documentation within defined timescales.
• The assessment of the design requirements of a particular component, system, assembly or installation in consultation with other departments.
• The production of designs which will favourably influence the cost and functional quality of the product and improve profitability and/or the company's reputation with customers.
• The undertaking of feasibility studies for future projects.
• Negotiations with vendors on aspects of bought out components and equipment, and with subcontractors or partner firms on interfaces.
• The assessment of the work of others.

• ability to identify problems
• ability to simplify problems
• creative skills
• sound technical knowledge
• sense of urgency
• analytical skills
• sound judgement
• decisiveness
• open mindedness
• ability to communicate
• negotiating skills
• supervisory skills.

The Engineering Design Process

The cost of a product, particularly in international markets, is only one factor which has a bearing on success. Reliability, fitness for purpose, delivery, ease of maintenance and many other factors have a significant influence and many of these are determined by design. Good design is therefore critical for success both in national and export markets and can only be ensured by adherence to a formal design process.

There are several suggested systems which vary in detail but are basically similar. The two figures below reveals an underlying similarity with the basic process being to identify the problem, generate potential solutions, select from the solutions, refine and analyse the selected concept, carry out detail design and produce product descriptions which will enable manufacture.










Question: Can you map each of the above two diagrams to that of the software product development life-cycle shown below?



Toggle Answer Answer: Business case - Market, Requirements - Specifications, Design - Concept and Detail Design, Implementation - Manufacture, Release - Sell.

The first and most important stage in the design process as outlined in Fig. 1.5 is the formulation of a Product Design Specification (PDS). Companies must use a logical and comprehensive approach to design if they are to profit from their labours. Therefore an all encompassing problem definition which is used to audit and guide the remainder of the design process is essential.

Question: Could you write a full product specification for an intelligent vacuum cleaner?
Toggle Answer Answer: battery life (3-4 hours), Durable (5-6 years), Artificial Intelligence (35% efficiency, will return to charging station when the battery is low), Vacuuming efficiency (80%), Noise pollution (quiet enough to watch TV), Voice Recognition, Small Size (laptop size), Ability to learn (create a floor plan), Low cost ($200-$300)...
See Intelligent Vacuum Cleaner specs
See also Intelligent Vacuum Cleaner specs (Summer 2024)

The Engineering Design Interface

It is essential that a design engineer has good communication skills. The design process begins with a design brief or Product Design Specification which triggers the design department to act. Two broad types of communication can be identified, internal and external.