Engineering vs Design - Page 1
Forum section: electronics / beginners

author: Hobby73
author_rank: Regular Contributor
timestamp: February 24, 2017, 04:27:41 am
content: Can you please provide a brief explanation of the difference between engineering and design? I hear these two terms used interchangeably, but I suspect there is a distinction.

author: bson
author_rank: Unknown
timestamp: February 24, 2017, 04:29:43 am
content: Technical design is part of what engineers do... in addition to many other things.

author: IanB
author_rank: Super Contributor
timestamp: February 24, 2017, 04:44:09 am
content: I would say that engineering is to apply science and technology to create something useful. Engineering may encompass design, planning, negotiation, communication, project management, people management, cost management, safety and loss prevention, legal and regulatory compliance, environmental considerations and various other things. Design is therefore one aspect of engineering.

author: Brumby
author_rank: Unknown
timestamp: February 24, 2017, 05:42:49 am
content: I believe it depends a lot on context - and even then, there can be subtleties that fall under the umbrella of "conventional understanding" - aka - assumed knowledge.

author: Rick Law
author_rank: Super Contributor
timestamp: February 24, 2017, 06:35:51 am
content: Quote from: Hobby73 on February 24, 2017, 04:27:41 amInternal combustionPiston Engine- poor design. Good piston engines are examples of great engineering overcoming the fault of the engine design.Rotatory Engineis a much better design. More efficient, much fewer moving parts...etc, etc, etc.

author: Richard Head
author_rank: Frequent Contributor
timestamp: February 24, 2017, 08:41:08 am
content: Rotatory?I thought all IC engines were rotatory in nature.

author: Brumby
author_rank: Unknown
timestamp: February 24, 2017, 09:36:05 am
content: Not so.The standard internal combustion engine operates through the reciprocating action of the piston. This transverse motion is transferred to rotary motion via the connecting rod and crankshaft.

author: ludzinc
author_rank: Unknown
timestamp: February 24, 2017, 09:42:08 am
content: Quote from: Rick Law on February 24, 2017, 06:35:51 amRotary as in Wankel Rotary, or Rotary as in WW1 aircraft?Better design?*cough* combustion chamber seal *cough*

author: tggzzz
author_rank: Super Contributor
timestamp: February 24, 2017, 10:08:35 am
content: As recounted by an engineering professor that also lectured at a design college...If you ask an industrial designer to design an egg:competent ones will produce something that is the right size, shape and colourgood ones will also produce something that is the right weightnone of them will produce an egg that can be eaten

author: mc172
author_rank: Frequent Contributor
timestamp: February 24, 2017, 12:51:44 pm
content: I'm struggling to answer the question directly, as in general most people either call themselves (or are employed as) an engineer or a designer.What is making it difficult for me to explain nicely is that engineers design things, but designers rarely engineer things. This is probably the best direct answer I can find:http://wiki.c2.com/?DesignVsEngineering"Design" is very abstract. Engineer is over-used, such as "waste disposal engineer" = binman, "thermal enhancement engineer" = radiator fitter. Designing stuff is part of my job but I am an engineer, not a designer. Design engineer, yes, but definitely not designer. Google explains it far better than I can:http://images.google.com/search?tbm=isch&q=designerIf I were for some reason looking to hire a designer, I would not expect them to have any technical knowledge other than how to use a computer and the most obvious difference between metal and plastic.A good engineer (or design engineer if you will) is someone that understands a broad range of technical disciplines, such as materials science, analogue and digital electronics, physics, maths, chemistry. They won't know everything there is to know of each subject, but will or should have a pretty good, relevant understanding suffice to do their job properly and usually then some because they find it interesting. An engineer should know the difference between 316 and 316L stainless steel (the metal), for example, or ABS and PTFE (the plastic), and will be able to exploit those differences for real-world scenarios.This is somewhat down to opinion, of course, as you will find that there are some people employed as engineers not doing anything like what I have just stated and will disagree, and vice versa.

author: mc172
author_rank: Frequent Contributor
timestamp: February 24, 2017, 01:08:42 pm
content: Quote from: Rick Law on February 24, 2017, 06:35:51 amWhat? That is entirely opinion and mostly incorrect. I've edited your post for accuracy below:Quote from: Rick Law on February 24, 2017, 06:35:51 amA piston engine is not a design of engine, it is a type of engine and is not an inherently poor "design".As an example, the BMW S54B32 is a particular design of a type of engine. The engineering is the effort put into fine detail of that particular design in order to make it meet its performance goals.What a load of utter- if Wankel engines are "superior to piston engines" because they are more efficient and have fewer moving parts, then since turbine engines are more efficient and have even fewer moving parts than Wankel engines (they have one moving parts) I can only conclude that Wankel engines are poor, faulty designs. Convenient that I have come to that conclusion as I completely agree!

author: snarkysparky
author_rank: Frequent Contributor
timestamp: February 24, 2017, 01:28:04 pm
content: Quote from: IanB on February 24, 2017, 04:44:09 amI wish they had told me this when I went into engineering. They only mentioned the cool math and physics and creative aspect. I absolutely hate dealing with most of the things engineering really is as you mentioned.

author: ConKbot
author_rank: Super Contributor
timestamp: February 24, 2017, 01:39:14 pm
content: Anyone can do design, engineering is minimising cost/material, or maximizing the output of an already existing widget using knowledge and tools available to you.I usually refer my gross overdesigning of mechanical or electrical things as "technicianing" (technician by title, get assigned light "engineering" work because we're shorthanded) I.e. "we need to power this with 5V 3A, can you make a converter board?" K, let me find a 6A buck converter, put an inductor so low resistance and large I know it's not gonna overheat, and put something together. Vs engineering it which would be actually checking it to make sure the load is what they say, figuring out efficiency requirements, and minimizing the size or cost of everything as needed, etc.

author: tggzzz
author_rank: Super Contributor
timestamp: February 24, 2017, 02:20:31 pm
content: Quote from: snarkysparky on February 24, 2017, 01:28:04 pmAlljobs have aspects you don't like; deal with it. Be grateful there are some bits youdolike, and that you probably have soem career options.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: February 24, 2017, 02:43:45 pm
content: Quote from: mc172 on February 24, 2017, 12:51:44 pmHaving been a good designer, I disagree that "would not expect them to have any technical knowledge other than how to use a computer and the most obvious difference between metal and plastic.". Good designers can get all of the materials and load aspects done correctly before the engineer sees the design and without input from an engineer. I certainly would not hire a designer that only had those limited qualifications. Most of the designers that I know are responsible for taking that part of the load from an engineer, whom, as pointed out, has many other duties to perform.As a designer, I was also responsible for electrical design, and was responsible for choosing components, wire sizing, BOM, mounting of any harnesses, etc.All that the engineer had to do with my designs was to do a cursory check that I had done due diligence, with occasional corrections, and sign off on the design.The step below the designer would be "drafter", and I still would not hire a drafter with only those qualifications.A designer is someone with a highly technical background that has extensive knowledge of materials, processes, parts, components, drafting ability and often much more. Usually has a 2 year degree in the area of technical, engineering or drafting. A designer has learned his/her skills from experience along with education and works in tandem with engineers.Despite some of the comments here that anyone can be a designer is simply not what I have seen. Designers are not quite engineers usually due to lack of degree in a university, but carry out many of the same duties.

author: mc172
author_rank: Frequent Contributor
timestamp: February 24, 2017, 07:16:25 pm
content: Ididsay:Quote from: mc172 on February 24, 2017, 12:51:44 pmIf you're doing load calculations and choosing materials, you're an engineer.

author: james_s
author_rank: Super Contributor
timestamp: February 24, 2017, 07:30:19 pm
content: Regarding Wankel and piston engines, "better" is subjective. The Wankel engine is certainly neat, it can produce a lot of power for the volume, it can rev very high, there are few moving parts, but it is not without disadvantages. Emissions tend to be dirty, fuel economy is poor, they have problems with rotor tip seals that were never really solved.All internal combustion engines have relatively terrible efficiency and are full of compromises. Nobody has found anything suitable to replace them yet in applications where one needs to convert a very high energy density fuel to mechanical work in a compact and inexpensive package though.

author: Rick Law
author_rank: Super Contributor
timestamp: February 24, 2017, 08:44:23 pm
content: Quote from: ludzinc on February 24, 2017, 09:42:08 amRotary as in WankelRotary used by Mazda RX100-RX400 series cars. The radial arrangement of cylinders used by aircraft in WW1 and WW2 are typically called Radial Engines at least in American English (and Wikipedia).Chamber seal for rotary engine was a problem that could be engineered out. Besides better efficiency, the much lower parts count and simpler construction leads to fewer problems requiring heroic efforts to solve.Piston engines too can have similar seal problemswhen poorly engineered. Don't forget the Chevrolet Vega for example, it was an aluminum cylinder without steel/iron lining. The chamber lost pressure in no time!Just think about these two problems in piston engines for example:(1) The intake/exhausts valves for each cylinder - at say 6000RPM, the number of open and close is huge. The acceleration and deceleration of the valves are huge! (push up to open, relax, pull down to close). And each valve literally crash back onto the valve seat, each time! Each valve needs to do that twice per cycle.(2) The piston connection to the crankshaft suffers a shock of an explosion each cycle. Goes super compression to push the shaft.Rotary engines has no piston, no valve, no crankshaft, etc, etc... None of those problems exist by design. But for the heroic effort in engineering to overcome piston engine's poor design, cars might not have came into being.An even better example between design v engineering might have beenPiston Aircraft engine verses Turboprop engine. The comparative simplicity of the designs and the comparative efficiency/power between them are huge. A good design leads to less engineering problems and could even lead to a more reliable product.

author: james_s
author_rank: Super Contributor
timestamp: February 24, 2017, 09:02:02 pm
content: There were two types of radial aircraft engines. The early type often called a rotary engine had a stationary crankshaft while the block and cylinders rotated around it with the propeller attached to that. Later came the more conventional radial engine which has a stationary bank of cylinders arranged around a central block which is stationary while the crankshaft rotated in a conventional manner to drive the propeller.My dad once had a Mazda with a Wankel engine, it was a fascinating bit of engineering and certainly had advantages, but it got terrible gas mileage, emission tests were not around yet or it would have really struggled to pass, and it had the usual rotor tip seal problems. There are valid technical reasons why even Mazda has given up on the Wankel for powering cars, it isn't some big conspiracy.

author: max_torque
author_rank: Super Contributor
timestamp: February 24, 2017, 09:41:40 pm
content: Quote from: Rick Law on February 24, 2017, 08:44:23 pmDon't take this the wrong way Rick, but it's pretty clear you're not a mechanical engineer!Rotary engines are not 'more efficient' than reciprocating internal combustion engines. They have a higher surface area to volume ratio, so a fundamentally lower overall thermal efficiency, and cannot easily leverage variable valve control and as a result again, cannot be as fully optimised as well as a typical poppet valve system.And of course, intake and exhaust valves do not "crash" shut or open. In fact, the losses is a typical mechanically operated poppet valve system are extremely low, just a small amount of friction and the tiny hysteresis of the valve spring. (The energy stored in the spring is returned to the camshaft on the closing flank )

author: Hobby73
author_rank: Regular Contributor
timestamp: February 24, 2017, 10:00:24 pm
content: This is the OP. Thanks for all replies!As stated above, the definition and distinction depends on the context. You can reference engineering as a profession, or engineering as a process, or an engineer as a professional individual with a skill set. Similar definitions can apply for design/designer. For my purpose of wanting a brief explanation of the difference, I will state the context as the process steps within a project lifecycle.So at the risk of oversimplifying, but with the objective of having a succinct explanation without referencing aircraft engines, I will adopt the definitions that thedesign processtakes functional requirements as input and produces logical and physical specs as outputs. And theengineering processtakes the specs as input and builds a new physical solution (e.g., prototype) or refines/modifies an existing physical solution as the output. That works for me!

author: xygor
author_rank: Regular Contributor
timestamp: February 24, 2017, 10:03:09 pm
content: Quote from: tggzzz on February 24, 2017, 10:08:35 amI wonder how many inedible Cadbury Creme Egg prototypes there were.

author: Rick Law
author_rank: Super Contributor
timestamp: February 24, 2017, 10:37:05 pm
content: Quote from: james_s on February 24, 2017, 09:02:02 pmQuote from: max_torque on February 24, 2017, 09:41:40 pmI take all constructive inputs gladly. You are right, I am no mechanical engineer. I am just recalling the pros and cons of the two engine types I read from auto-magazines of the era. Since I have no dog in this fight, I will accept that yeah, perhaps rotary isn't that great a design.That said,the two engine types (designs) clearly distinguishes the design part versesengineeringthat design to become a real product.Quote from: Hobby73 on February 24, 2017, 10:00:24 pmAnd yeah it does depends on context. I found thisdesign vs engineering similar to strategy vs tactics. If the agreed strategy is that "we want to control the Asia market" and decided on the tactic of "first dominates the Japanese market and then grow westward." The executive given the task toexecute the tactic will then form his own strategyon "how to dominate the Japanese market".

author: vk6zgo
author_rank: Super Contributor
timestamp: February 24, 2017, 10:52:12 pm
content: Quote from: ConKbot on February 24, 2017, 01:39:14 pmThe Tech's clunky old design will still be trundling along in 20 years time.I give the "optimised" design three to five!

author: mc172
author_rank: Frequent Contributor
timestamp: February 24, 2017, 11:21:05 pm
content: Rick, I'm not being a dick when I type this - I am here to learn but also impart correct information based on my knowledge. I hope you don't take this the wrong way as it is meant to be constructive.Quote from: Rick Law on February 24, 2017, 08:44:23 pmEmphasis by me.The acceleration and deceleration is close to sinusoidal on the open stroke and close stroke. Piston engines have valves which are forced open by a camshaft but are "pulled" back into the closed position by rather strong springs. They are not forced closed.The transition between opening, open (stationary) and closing is somewhat less sinusoidal and is the most aggressive point of the cycle but far from "crashing" as you stated. I also note that you hint at the point at which the valve closes being the "crashing" point. Often the upper speed limit of a particular engine is set by the strength of the valve springs* - there is a fine balance between making the moving mass of the valves as low as possible and the springs very, very stiff in order to get them to close quickly and follow the closing profile of the camshaft at high speed, and reducing the parasitic friction of the valve system down to an acceptable value. The stiffer the springs, the better the valves follow the profile of the camshaft at high RPM, however the parasitic drag of the valvetrain goes through the roof and you end up using more power to drive the valvetrain than you gain by closing the valves quickly.*It is as equally often set by the maximum inertia of the pistons and the shear strength of the gudgeon pin, which is normally made of something quite exotic and very, VERY hard. Included for completeness.It does not matter what the absolute rate of acceleration (inversely deceleration) of the valves or anything is. As long as they are designed to be strong enough, the design is adequate. These design challenges are present within piston and Wankel types.There is also a point whereby the exhaust valve does not follow the close profile of the camshaft at high speed, thus resulting in a less than smooth transition between the spring closing the valve and valve being on its end stop (i.e. closed) as the camshaft is no longer modulating (or moderating) it. This is engineered deliberately in order to break up the "coke" deposits left by normal operation.Quote from: Rick Law on February 24, 2017, 08:44:23 pmThe burn inside a piston engine is fairly tame and is not really an "explosion". It is subsonic - the correct name is "deflagration". Both Wankel type engines and piston type engines have the exact same burn characteristics as the fuel and stoichiometric ratios are the same. The forces are imparted to the crankshaft in the same way - close to tangentially, therefore piston engines suffer no higher peak forces when compared to Wankel engines. If anything, the Wankel engine is susceptible to higher peak loads as the bearing loads of an entire chamber burn are spread over only one tooth of the central gear. Gears tend to have load areas closer to line contacts, as opposed to approaching half a circumference of a typical connecting rod.Quote from: Rick Law on February 24, 2017, 08:44:23 pmRotary engines have one piston per "rotor". The rotor is the piston.Some steam engines have no discrete valves - the piston forms the valve. This does not mean it has no valves, as valves of any description naturally exhibit loss.Wankel engines have a crankshaft, it is just not traditonally "cranked" and instead it has gear teeth cut onto it.

author: james_s
author_rank: Super Contributor
timestamp: February 24, 2017, 11:44:24 pm
content: Quote from: max_torque on February 24, 2017, 09:41:40 pmThere are different ways to define efficiency. Due largely to the fact that Wankel engines are essentially two-stroke, with a power stroke on every revolution of the crankshaft, have a high *volumetric* efficiency, in other words they produce a lot of power for a given displacement and physical size of the engine. They also produce a lot of power for the weight of the engine, those are both valid measures of efficiency, yet completely different from the fuel efficiency, mechanical energy extracted per unit of fuel consumed. That is arguably the most important measure of efficiency for a car engine, and that is one area where the efficiency of a Wankel engine has been mediocre at best.Piston engines are not all that bad really, after more than a century of refinement they are dependable and reliable, fuel efficiency is quite good compared to other known methods of extracting mechanical energy out of combustible fuel. It's not unusual for a car engine to go 300,000 miles or more with little trouble so long as you keep oil in it. I don't foresee any further revolutionary improvements in the internal combustion engine of any type, just gradual evolution.

author: Cerebus
author_rank: Super Contributor
timestamp: February 25, 2017, 03:29:31 am
content: Quote from: mc172 on February 24, 2017, 01:08:42 pmI think here we have a classic example of one difference between designers and engineers. A designer will understand that an illustrative example is just that, and will try to draw from it. An engineer will pick apart the minutiae of why your example is wrong, often at length.

author: Cerebus
author_rank: Super Contributor
timestamp: February 25, 2017, 03:36:48 am
content: Quote from: ConKbot on February 24, 2017, 01:39:14 pmSadly no, not "anyone" can do design. You only have to look at the many, many examples of badly designed things that we all encounter on a daily basis to realize that good design is rare, and good design ability is a rare skill.

author: Smokey
author_rank: Super Contributor
timestamp: February 25, 2017, 03:51:07 am
content: I love that a big chunk of this thread is talking about engines.Like it has been said above, a general definition is hard. But specific examples are pretty easy.I hear stories about a former non-engineer CAD designer at another company who got too much mechanical engineering responsibilities. The stuff he made typically was initially the right size and shape mechanically, but there were always problems like not getting the materials correct for the environment or not understanding how things would wear over time. The stuff he made was never reliable or robust. These are mistakes a good mechanical engineer would be expected not to make. I think that's the best example I got.My shot at a general definition I guess would be: The engineer gets to work out all the details that are critical for the thing to work right, and the designer gets to put the rest of the thing together based on the rules the engineer laid out for him.Or if you work at a small company then you get to be the engineer, designer, plumber, receptionist, etc.

author: Rick Law
author_rank: Super Contributor
timestamp: February 25, 2017, 06:21:55 am
content: Quote from: Cerebus on February 25, 2017, 03:29:31 amThanks for saying that.I was getting frustrated about the discussion of the details to the point I regret having selected engine design as an example - or my failure in explicitly saying whichever engine is better (or not) doesn't matter - the purpose was to highlight the design of the engine verses the engineering of that design.We are all trained to do certain things.This reminds me of an observation made by someone: "If you pointat somethingwith your finger, most people will look at what you are pointing at. But,a dermatologist will just look at the skin of your hand and finger."

author: james_s
author_rank: Super Contributor
timestamp: February 25, 2017, 07:13:30 am
content: Quote from: Rick Law on February 25, 2017, 06:21:55 amSo will a cat, in most cases.

author: tggzzz
author_rank: Super Contributor
timestamp: February 25, 2017, 08:32:14 am
content: Quote from: Smokey on February 25, 2017, 03:51:07 amThat's a good instantiation of the point made by the engineering professor.QuoteThe engineer gets it to work, the designer makes it look pretty and (optionally) be easy to use.

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: February 25, 2017, 09:53:33 am
content: Quote from: tggzzz on February 25, 2017, 08:32:14 amAs a product designer I need to strongly oppose that!Ease of use and looks are just two of the various parameters you need to look into as a designer. To tell you the truth, I am not happy with the term "designer" in general, because it is so fuzzy. Even if you ask two designers on what a designer does, you will be left with at least three valid, but different answersThere is inflationary use of the word in everyday speech also, what adds to the problem of clearly defining it.My main job is to listen to everyone on the table in any project stage. The designer needs to be aware of everything that is connected to the product to be able to figure out the best way to get things going in the right direction. In order to truely be a link between the different departments the designer needs to have a deep understanding of what everyone does and is good at doing. Also it helps a lot if you can speak all the different languages. You need an understanding of how everything works from marketing and sales through part sourcing and all of the supply chain, engineering, manufacturing, after market and customer relations...At one point you might be the one that needs to bring it all together in a product, so it is best you also technically understand what works and what does not. Of course you do not need to draw every part on your own, that is why you usually work together in a team with everyone on the table.But then again there are a lot of different positions for a designer to work in. You might be an a technical engineer, an illustrator, a project manager, the guy with the weired ideas from r&d, the company's universal translator, an input buffer, or something totally different...I hope you get my point

author: tggzzz
author_rank: Super Contributor
timestamp: February 25, 2017, 12:01:04 pm
content: Quote from: frozenfrogz on February 25, 2017, 09:53:33 amIn which case there is no difference between a designer and an engineer - since engineers have to do all that too!My list was of the minimum essential distinction between the two disciplines. That designer and engineers frequently and beneficially take on more roles merely clouds the issue in question.

author: vealmike
author_rank: Regular Contributor
timestamp: February 27, 2017, 11:50:36 am
content: The public seem to think that the guys who install your satellite dish, repair your washing machine, change the oil in your car are all engineers.They are not (or at least they are not working as engineers.)There are two types of engineer. The first designs stuff, using complex mathematics, systems and applied physics to solve problems. The second drives a steam train.All the others are installers, spanners or repairmen.Because of this common confusion, many engineers amend their job description from "Engineer" to "Design engineer".Design can be practised without engineering (eg graphic design) but engineering can not be practised without design.

author: tszaboo
author_rank: Super Contributor
timestamp: February 27, 2017, 01:58:26 pm
content: Quote from: vealmike on February 27, 2017, 11:50:36 amYes, nowadays even handymen calls themselves engineers.To the original topic: I tell girls that I am an electronics designer, because than I dont sound as a big nerd and they dont leave me immediately. When design is mentioned, then people associate that with with rounded rectangles and pencils on a drawing board.