Design, Drawing, and Practical Skills Assignment Report - University

This report provides a comprehensive overview of engineering drawing, design specifications, and the factors affecting electric car performance. It begins with a detailed description of the engineering drawing process, including sketching, proportioning, and formal layout, highlighting key elements such as drawing sheet sizes, dimensions, and specifications. The report then delves into design specifications, emphasizing the importance of correct generality and the issues arising from ambiguity. The discussion extends to factors influencing electric car performance, such as engine efficiency, friction reduction, drag force, horsepower, and handling capacity, offering insights into how these elements impact vehicle speed and stability. Finally, the report addresses testing strategies aimed at optimizing the speed, carrying capacity, and efficiency of electrically powered carts, touching upon legislation and emissions performance metrics like the New Europe Drive Cycle (NEDC). This report is a valuable resource for students studying mechanical engineering and related fields, offering practical knowledge and theoretical insights.

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DESIGN, DRAWING AND PRACTICAL SKILLS ASSIGNMENT REPORT
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Design, Drawing and Practical Skills Assignment Report
Description of the process of producing an engineering drawing
An engineering drawing refers to a type of technical drawing that defines entirely and the
requirements for engineered items. As such, it is drafted following the layout standard
conventions, appearance size, nomenclature, etc. consequently, all geometric features regarding
the product or component are captured accurately. Notably, the drawing covers the electrical and
mechanical design of the car (Luzadder, 1992, 14).
First of all, engineering drawing starts with sketching. Sketching gives the pictorial view of the
desired final product. For instance, the side view, the top view, and the front view are included.
Similarly, a 3D sketch is also possible and will provide a better view of the final project.
After that, get the proportions right. It is evident that making a drawing is time-consuming. It
starts with a poor drawing but gets better later. After that, choose the formal layout. A sketch
then followed by the orthographic projection (Dieter and Schmidt, 2013, 108). In both the first
angle projection and third angle projection, details about the front elevation, the plan, and the end
elevation should be developed.
Finally, final design with detailed drawing containing all the components is drafted. Thorough
revision should be done to ascertain that all drawing problems are solved. That gives the accurate
details used in the final design of the project.
Five key aspects and elements that need to be present if an engineering drawing is to be used as
a basis for manufacture.

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Firstly, drawing sheet sizes are identified. The drawing paper is available in rolls of different
widths and trimmed standard sizes. Most of which are printed with the borders and the title
block. Similarly, there exist five standard sizes that are frequently used. Drawing sheets can be
employed either with longer sides placed vertically or horizontally. Therefore, the original
drawing has to be done on the smallest sheet as it permits the required resolution and clarity.
The drawing sheet layout is an important aspect as it facilitates the reading of the drawing.
Moreover, the plan should be clear and neat in its appearance to permit easy location of essential
references. Borders are also specified in all the sheet sizes and are required to be 20mm for size
A0 and A1 and a width of 20mm for other sheet sizes (Dieter and Schmidt, 2013, 108). Also,
there exists drawing sheets that have features such as the title block, the center marks, frame and
other optional features.
After that, engineering drawings should have dimensions. A detail drawing should provide the
complete description of the part as well as the description of the furnish size. Such information is
provided given concerning the location of holes, type of material or the distance between
surfaces. On a drawing, they are illustrated by use of lines, figures, symbols, and notes.
Furthermore, dimensions are classified into the functional dimension, non-functional dimension,
and auxiliary dimension.
Information on a drawing is fundamental. Thus, all information has to be numbered. As such,
many numbering systems exist. Various digits of the numbers indicate different details such as
the nature of the part or the machine model number. For instance, companies use numbers such
as K2-70524 or 70524 without a prefix (Luzadder, 1992, 14). Moreover, specifications regarding
the material, general notes, finish, and tolerances are located near the title block. Finally, all

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drawings are made to a particular scale which is indicated near the title block. However, if
different levels are applied, they should be stated on own designs.
A design specification
A design specification refers to detailed documentation that provides information about a project
that is to be executed to set the criteria with which developers or engineers will need to follow to
ensure successful completion of the set target for the project. In most scenarios, a design
specification plays a significant role where a structure or a given product is to be designed as per
specific needs or requirements. Design specifications should have all the necessary drawings,
dimensions, ergonomic, aesthetic, environmental, cost and maintenance factors that will be
required. It should also contain the safety, quality, description, and documentation. Design
specification gives specific details of how a design on a project should be undertaken thus
enabling work to be done efficiently and more (Dym et al., 2009).
Issues of Having Ambiguity within a design specification
Uncertainty results in inaccuracy and complexity in the specification, this may lead to any loop
hole in the specification eliminating competition and allowing a bidder to take advantage of the
purchaser. Moreover, it results in the inability to understand the specification by both the bidder
and the buyer. It further results to the inflexibility of the specification which later defeats the
competitive bid process.
Similarly, it leads to lack of legibility and concise in a specification and causes additional
specification which tends to be expensive. It also becomes unfair to bidders that thus inhibits the
ability for competitive bidding by several bidders.
Importance of having Correct level of generality in a design specification

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When a bidder is considering a newly manufactured product, the most crucial step is conveying
the impression to some team developers, so the idea is converted into some engineering drawings
portraying plans to be used for manufacture. In case the idea is not communicated properly and
efficiently, repetitions may occur in the design and analysis stage of conception.
Thus, the development processes are bettered if design aims are defined. The importance of the
objectives is rated; as a result, a plan written. One of the methods that are used to deliver the
design objectives is the use many design parameters and then evaluate the meaning of each part.
The process of noting down the parameters forces a person to identify the goals which give the
designers and engineers vital information concerning their relative importance. Therefore, the
finished product impression can vary based all the input design aspects.
For example, if we consider creating a coat hanger, we note that the relevant parameters to be
considered include the strength, the cost, aesthetics, the capability to clutch pants, rust, and the
inability to crease pants. Thus, on a scale of 0 to 4, a customer may produce for the ranking of a
hanger based on a scale of 0 to 4 (Dym et al., 2009).
After the designers have got a distinct understanding regarding the design goals and have written
an engineering drawing specification, many tools can be applied to commence the entire design
process. Thus, design sessions can be helpful in generating product design ideas. Similarly,
drawing hand-sketches is a perfect way to begin communicating the real physical concepts.
Eventually, models of parts are produced by the computer program 3D, models which can be
further affected by photo-realistic interpretations (Bucciarelli, 1988,162).
Besides, a careful understanding of the materials and engineering manufacturing processes is
vital to a profound design. Moreover, the selection of the materials and manufacturing processes

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has to match the design requirements making some methods being suited to high volume and
others high volume production.
Before the detailed design can start, the first step of looking at the design objectives has taken
place. Thus, a list bearing the design parameters and the rating based on their application and
importance is rendered helpful during the first communication.
Factors that would affect the electric car's performance
In the early days, the design of automotive constituted a carriage without a horse. As such, the
first cart was manufactured without much consideration to the center of mass, aerodynamics and
other safety features in modern vehicles. Since then, design engineers have made several changes
that have improved performance regarding the carriage capacity, the speed, and efficiency.
Notably, the improvements have been attributed to by enhancement in technology. Thus,
improving the ability of engineers to design cheaper, faster, comfortable and more efficient
electric carts for the consumers. However, there exist some factors that affect the performance of
electric cars’ as follows.
Firstly, engine efficiency is directly proportional to the effectiveness of the vehicle. Individual
metals used in current engines can be understood through a materials science approach. For
example, when pistons are made of light materials, we can analyze the parts regarding the
momentum(P). P equals mass times velocity. With reduced weight, the impulse force that is
required to modify the momentum is reduced. Hence, a lighter material requires less force and
the energy wasted in manufacturing the engine can be applied in driving the engine.
Secondly, reducing the friction in moving parts of the engine is another way of improving the
efficiency. All these are done by use of synthetic oil with less viscosity, special coated cylinders

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and cylinder walls based on chemistry point of view. As a result, energy loss in the form of
friction is minimized thus better efficiency.
Thirdly, when thinking of vehicle performance, speed becomes inevitable. Often, the question
becomes, what factors affect the speed of the car and how can we mitigate the barriers that limit
speed? Drag force and horsepower are the underlying factors which influence the speed of a cart.
Therefore, a cart can be made faster by building a superior engine. However, the drag force is
proportional to the square of velocity. As a result, the faster the automobile is traveling, the
higher the opposing forces.
After that, Horse power measures the amount of force an engine can apply to a cart over a
specified amount of time. It refers to a measurement of power in Watts. Instantaneous Power is
measured using the equation P=FV in case of motion in a straight line. Additionally, F=MA, so
that P=MAV. Hence, to get the answer in horsepower, the solution is divided by 746 since one
horsepower equals to 746watts (Roberts et al., 2014, 337). This explains why an engine can be
rated for a given power. Some might think that if an engine from a heavy vehicle and placed in a
light weight vehicle, the car might generate more horsepower. However, because A=F/M the
acceleration of the car will increase with a decrease in mass, resulting in a constant horsepower.
Finally, the handling capacity is a consideration in design. The best design is that which the
engine is placed close to the center of the car. With this configuration, the engine becomes the
center of mass for the car. If you have a car in which the center of mass is at the back or the front
side, the forces acting on the point will break the tires grip on the road. Which is as a result of
force having to overcome the friction of only two tires instead of four. For example, a car
negotiating a corner has many forces acting on it. For instance, friction acting on the tires cause
centripetal force which makes the car to move in a circle. Contrary, the momentum of the car

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moves in a direction such as to oppose friction force. The sum of all the forces should be equal,
or the tires would slide. Moreover, if the center of mass is in the center, the momentum will
oppose the friction over the four tires. Similarly, if the center of mass acts on the back tires, the
momentum force will have to overcome the friction on the rear tires. Hence, a car with the
engine at the center is more stable and safe.
The testing strategies to optimize the speed, the carrying capacity and efficiency of an
electrically powered cart
The legislation and emissions performance. There exists metrics for measuring the internal
combustion engine efficiency. For example, the “New Europe Drive Cycle (NEDC)” (Bielaczyc
et al., 2011). NEDC which is a 1200s long cycle is used to test all engines and simulate a range
of scenarios as shown in figure 1 below. In the European union, the figures for fuel consumption
for new cars are quantified based on the NEDC. Hence, the method used to boost cold-start
efficiency should be useful. Thus, fuel consumption is reduced through NEDC test.
Fig 1. Speed- time curve for the NEDC
The consequences of cold-start engine

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The steady state performance of the internal combustion has improved noticeably over time. A
trend that can be attributed to a series of developments that include the use of advanced
lubricants, rail fuel injection, sophisticated engine control means and the use of catalytic
converters on most vehicles. However, the cold-start performance of vehicle engines remains
challenging (Dohner, 1980, 21) .
Engine fuel consumption is related linearly to the ambient temperature as shown for a Euro 1
compliant S.I. engine. Over the drive cycle, the use of fuel increased by 18% as a result of the
decrease in room temperature from 31 °C to −2 °C (Iodice and Senatore, 2016, 1). Moreover, a
similar trend for the other variants of engines (a 1400 cc 4-cylinder S.I. engine, a 1200 cc 3-
cylinder S.I. engine and a 1800 cc S.I. engine) were recorded with a 3.3 l S.I. engine (Bielaczyc
et al., 2011).
Such notes eased cart designers since NEDC test is needed to be carried out at a temperature
ranging between 20 °C and 30 °C. Also, the consumption of gasoline engine fuel averagely
dropped by 10% over the period of the NEDC. Consequently, whereas the vehicle might have
performance credentials that are acceptable once warm, the low-quality cold-start performance
could result in failure of the vehicle in emission tests. These behaviors can lead to high fuel
consumption. Therefore, improving fuel consumption during the cold-start and warm-up phases
is rendered critical since consumer driving behaviors repeatedly include short distance trips and
as a result of the engine never reaches its required working temperature. It is estimated that up to
80% of trips made in the United States of America is less than 15 km as opposed to the average
European vehicle journey that is approximately 10 km (Roberts et al., 2014, 337). Later on, it
was concluded that a third of automobile journeys are completed before the engine is fully warm.

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References
Luzadder, W.J., 1992. Introduction to Engineering Drawing: The Foundations of Engineering
Design and Computer Aided Drafting. Prentice Hall PTR.
Dieter, G.E. and Schmidt, L.C., 2013. Engineering design (Vol. 3). New York: McGraw-Hill.
Dym, C.L., Little, P., Orwin, E.J. and Spjut, E., 2009. Engineering design: A project-based
introduction. John Wiley and sons.
Jones, J.C. and Ertas, A., 1996. The engineering design process. Wiley.
Bucciarelli, L.L., 1988. An ethnographic perspective on engineering design. Design studies, 9(3),
pp.159-168.
Roberts, A., Brooks, R. and Shipway, P., 2014. Internal combustion engine cold-start efficiency:
A review of the problem, causes and potential solutions. Energy Conversion and
Management, 82, pp.327-350.
Iodice, P. and Senatore, A., 2016. A numerical-experimental approach to assess emission
performance of new generation engines during the cold transient. International Journal of
Automotive & Mechanical Engineering, 13(3).
Bielaczyc, P., Szczotka, A. and Woodburn, J., 2011. The effect of a low ambient temperature on
the cold-start emissions and fuel consumption of passenger cars. Proceedings of the Institution of
Mechanical Engineers, Part D: Journal of Automobile Engineering, 225(9), pp.1253-1264.
Dohner, D.J., 1980. A mathematical engine model for development of dynamic engine
control (No. 800054). SAE Technical Paper.