[Sutripta]

Originally Posted by SS-Traveller

This thread seeks to answer just that: So what exactly constitutes a "modern" engine, as opposed to an "outdated" one?

Hi,
I'd say it is a question with no easy answers. And rather than modern, I'd use the term contemporary.

All machinery is designed/ built with a goal/ objective, subject to numerous constraints. Ultimately what comes out is a mass of contradictions and compromises. It is the (intelligent) choice of compromises which will separate one product from another.

If the objective is in tune with the times, and the objective is met with reasonable success, I'd say that the machine is contemporary. This is entirely independent of how that objective is achieved. For todays engines, the newer objectives (the old ones of low cost of production, durability, specific power/ fuel consumption etc remain) would be emissions/ carbon footprint. Weight and packaging have also become increasingly important nowadays. Specific power becomes an issue essentially for regulatory constraints (Think of our 1200 cc or Japans 600 cc or ASEANS 250 cc for mobikes etc)

Though there will be differences amongst manufacturers, some broad trends will immediately be visible to us laymen. For instance, we can say that a modern diesel be a Turbo CRDI DOHC 4 valve head. This is not contemporary by itself:- it is the accepted solution to achieving a contemporary objective - a diesel which drives like a petrol, has the economy of a diesel, and is green enough for today's world. So if we see these features in an engine, we say 'modern/ contemporary'.

Please note that I'm talking of contemporary rather than great. Great engines have something else. These do their work with finesse and elan.

A counter question. What exactly is wrong with a pushrod operated V8 petrol? To be consigned to the history books? If so, why?

My two bits.

Regards
Sutripta

[dhanushs]

^^ +1. Exactly what I meant to convey from my post. You put it across in a very mature way.

Originally Posted by SS-Traveller

Would you like to (for the sake of debate of course) quantify/enumerate the modern features of Honda engines, and do a quick comparison with other similar engines available in India?

Again, SST, speaking broadly, and not going into the technicals, Honda engines manage to best achieve the newer objectives (That Sutripta sir mentioned), in a perfect balance. ie, in todays market, the most sought after qualities are, Fuel Efficiency, Performance and Emissions, and may be NVH. IMO, Honda engines, when compared to the competitors, have the best balance among these.

Now, one technology, that pops into my mind when the name Honda flashes in the Forums, is the VTEC. At the time it was introduced in India, ALL other engines were made to look a decade old. Now.. that is Modern!!.

[Aroy]

Another aspect of the Honda engines is that they age extremely well. Maintenance is low and the intervals between overhauls is long. In contrast modern German engines have much better performance but suffer from costly maintenance and are much less reliable. Both are modern designs!

Regarding pushrods.
. These require a lot of maintenance - adjustments to individual tapettes and are more complicated, thus reducing reliability.
. If you want multiple banks, as in case of 4 or 5 valves/cylinder, the mechanism becomes even more complicated.
. So from the point of view of maintenance and reliability, overhead CAM design is better, hence its preference in mass market.
. The labour costs in case of over head CAM engines are lower as less components have to be assembled and adjusted.

Pushrods though, offer a lot of scope for tuning individual valve characteristics, not possible with over head cam design.

[Sutripta]

Regarding the pushrod V8, would like to know what others think. (My thoughts are heretical!)

If one came across an engine in the 70s/ 80s with any one of these:- turbo, DOHC, 4 valve head, what would one think?

Ducati's desmo. How should one classify that?

[vina]

Originally Posted by Sutripta

Hi,
I'd say it is a question with no easy answers. And rather than modern, I'd use the term contemporary.

All machinery is designed/ built with a goal/ objective, subject to numerous constraints. Ultimately what comes out is a mass of contradictions and compromises. It is the (intelligent) choice of compromises which will separate one product from another.

If the objective is in tune with the times, and the objective is met with reasonable success, I'd say that the machine is contemporary. This is entirely independent of how that objective is achieved. For todays engines, the newer objectives (the old ones of low cost of production, durability, specific power/ fuel consumption etc remain) would be emissions/ carbon footprint. Weight and packaging have also become increasingly important nowadays. Specific power becomes an issue essentially for regulatory constraints (Think of our 1200 cc or Japans 600 cc or ASEANS 250 cc for mobikes etc)

Though there will be differences amongst manufacturers, some broad trends will immediately be visible to us laymen. For instance, we can say that a modern diesel be a Turbo CRDI DOHC 4 valve head. This is not contemporary by itself:- it is the accepted solution to achieving a contemporary objective - a diesel which drives like a petrol, has the economy of a diesel, and is green enough for today's world. So if we see these features in an engine, we say 'modern/ contemporary'.

Please note that I'm talking of contemporary rather than great. Great engines have something else. These do their work with finesse and elan.

A counter question. What exactly is wrong with a pushrod operated V8 petrol? To be consigned to the history books? If so, why?

My two bits.

Regards
Sutripta

The thread is overtly about engines, but there is a strong undercurrent of what is a modern engineering design in general. I would add my 2 cents from my experiences as a practicing design engineer (albeit in the electronics field):


For any job at hand for a design engineer no single answer is the right answer usually. A good design always is a tough balancing act. Overt and not-so-overt specs abound (e.g. people may be surprised how often is reliability specified the last, and understood the least - an example - while digital systems are generally thought to be more reliable than analog, almost no digital systems designers have any clue about what makes systems unreliable and how).

to achieve the purpose many tools and techniques are available most of the times (the real cutting edge stuff happens when one goal supercedes everything else - but that is beyond the majority of engineering - in such applications new techniques are developed and mastered and then later applied elsewhere).

Some of these tools/techniques can be reasonably called more complex or, colloquially, modern because they are more expensive to implement (in terms of cost, design time, risk ...)

So far was the background. Coming to the original question, from the point of view of a design engineer - if you can achieve the goals by using old-school practices and no new and "modern" techniques - it is more often than not a better design. Rest is marketing gimmick - you basically have "modern designers" who can't do design rather than modern designs.

[SS-Traveller]

Interesting direction this thread is taking!

So a V8 pushrod may be *outdated* because it is complicated, fiddly to adjust properly and not perfect in their long-term performance; yet, it may be *modern* (or perhaps it'd be safer to call it *contemporary* ??) because they do have fail-safe performance over extended periods of use (though not in perfect tune), and would be preferred for rugged / heavy-duty applications over camless valves because of the *unproven* nature of this newer (more modern!) tech.

Originally Posted by vina

Some of these tools/techniques can be reasonably called more complex or, colloquially, modern because they are more expensive to implement (in terms of cost, design time, risk ...)

Therefore, is COMPLEX = MODERN? Or is it any of the following?

• SIMPLE = MODERN (rephrased: Less moving parts = Modern)
• SIMPLE = OUTDATED (Complicated construction is a spin-off of technology, to quote vina - no offence here, vina! )
• RELIABLE = MODERN (Is the national 1.3L Multijet engine the epitome of modernity?)
• NEW TECH = MODERN (Ok, this one is obvious!)
• EXTREMELY FUEL-EFFICIENT = MODERN (The Indica 1.4L diesel with 25 km/l ought to be the most modern engine in India - but is it?)
• HIGHER POWER OUTPUT PER CC = MODERN (The pushrod V8 can do that too, so is it modern?)
• MODERN = FAILSAFE (The DSG gearbox is obviously not *modern* by this parameter!)
• EXPENSIVE = MODERN
• HITHERTO UNKNOWN MATERIALS = MODERN

Let the thoughts continue!

[Sankar]

My opinion of a modern engine is: High efficiency with higher specific output with lower fuel consumption and meets pollution norms in effect or beyond and has good reliability. For me any engine that satisfies the before mentioned criteria is modern enough for me.

Modern Eg: Suzuki K12/K10, Honda 1.2Ivtec, Fiat 1.3 Multijet, Tata 2.2 Dicor

The Kappa 1.2 engine is a bit of confusion for me. Yes its new but its specific output or fuel efficiency doesn't qualify it to be modern engine as per my beliefs. I would call it new but doesn't have the qualities of a modern engine, not even with variable valve timing technology.

Not so modern Eg: Chevy STec 1.2, Figo's 1.2 petrol, Kappa 1.2, Ford 1.4TDCI, Tata 3.0 Dicor

[dustom_99]

Imo its the power to weight ratio of the plant itself,rather that power/cc that puts an engine on the charts.
Why would you care if its 2400cc if it is light enough to compete with 1.5l or 2l motors.
Another point is,wht point does HIGHER FE puts through if you are not making power atleast equal to the cmpttion.
so fuel consumption/bhp (both at rated load and full load) should be taken into account.
If indica puts out 25 or whatever kmpl,it does not mean a thing,because 1.motor itself is atleast 30% heavier than other same segment motors.
2.it manages only 12-13kmpl at rated power on full load.
And NVH ETC are not comparable either.
It does not matter,whats inside a motor.
I did a comparo before I started my project,b/w 1.3l fiat multijet,and 1.5l crdi.
Crdi was 18kg heavier than 1.3l multijet,but same time it made 35odd bhp ,50nm more than 1.3mill.
FE and nvh were similar on both.
So which one is outdated is any ones guess.

[Sutripta]

Originally Posted by SS-Traveller

Therefore, is COMPLEX = MODERN? Or is it any of the following?

• SIMPLE = MODERN (rephrased: Less moving parts = Modern)
• SIMPLE = OUTDATED (Complicated construction is a spin-off of technology, to quote vina - no offence here, vina! )
• RELIABLE = MODERN (Is the national 1.3L Multijet engine the epitome of modernity?)
• NEW TECH = MODERN (Ok, this one is obvious!)
• EXTREMELY FUEL-EFFICIENT = MODERN (The Indica 1.4L diesel with 25 km/l ought to be the most modern engine in India - but is it?)
• HIGHER POWER OUTPUT PER CC = MODERN (The pushrod V8 can do that too, so is it modern?)
• MODERN = FAILSAFE (The DSG gearbox is obviously not *modern* by this parameter!)
• EXPENSIVE = MODERN
• HITHERTO UNKNOWN MATERIALS = MODERN

Let the thoughts continue!

How about
MEETS THE IMPORTANT MAINSTREAM REQUIREMENTS OF THE DAY = MODERN

Regards
Sutripta

[noopster]

Is a bigger engine (in cubic capacity) necessarily more robust? For example, the 2.4 litre Innova engine in low state of tune delivering 100 bhp versus say the lower powered engine delivering similar power (random example the VW Vento 1.6 TDI drivetrain). If Toyota plonks the 1.6L engine into the Innova will it wear out faster simply because it is a smaller engine?

[vina]

Originally Posted by SS-Traveller

Interesting direction this thread is taking!

So a V8 pushrod may be *outdated* because it is complicated, fiddly to adjust properly and not perfect in their long-term performance; yet, it may be *modern* (or perhaps it'd be safer to call it *contemporary* ??) because they do have fail-safe performance over extended periods of use (though not in perfect tune), and would be preferred for rugged / heavy-duty applications over camless valves because of the *unproven* nature of this newer (more modern!) tech.


Therefore, is COMPLEX = MODERN? Or is it any of the following?

• SIMPLE = MODERN (rephrased: Less moving parts = Modern)
• SIMPLE = OUTDATED (Complicated construction is a spin-off of technology, to quote vina - no offence here, vina! )
• RELIABLE = MODERN (Is the national 1.3L Multijet engine the epitome of modernity?)
• NEW TECH = MODERN (Ok, this one is obvious!)
• EXTREMELY FUEL-EFFICIENT = MODERN (The Indica 1.4L diesel with 25 km/l ought to be the most modern engine in India - but is it?)
• HIGHER POWER OUTPUT PER CC = MODERN (The pushrod V8 can do that too, so is it modern?)
• MODERN = FAILSAFE (The DSG gearbox is obviously not *modern* by this parameter!)
• EXPENSIVE = MODERN
• HITHERTO UNKNOWN MATERIALS = MODERN

Let the thoughts continue!

You have taken it in the direction where you are implicitly asking the question - define modern.

Originally Posted by Sutripta

How about
MEETS THE IMPORTANT MAINSTREAM REQUIREMENTS OF THE DAY = MODERN

Regards
Sutripta

Sutripta sir has given a definition that most design engineers would agree with, but many people on the street may not.


By linguitic definitions, modern=new. Anything old is not modern. However that is not exactly how people understand it, though people's understanding does boil down to this over the longs run.


For example in semiconductors, anyone will tell you that 20nm is more modern than 28nm, which was more modern that 40nm, and so on. However "modern" industrial ICs do not even touch these nodes - the reliability is not up to the mark usually.

Still there are "modern" circuit techniques that can make a 40nm chip as reliable as a 130nm.




My point in my earlier post was that while in case of techniques and tools available it is much easier to see what is "modern" aka new, in case of products or systems (e.g. engine) which are formed by trading off several requirements (usually including cost) and using multiple techniques it is hard to say whether one overall product is more modern than another in the aggregate.

Another point I was trying to make was that while in general public perception modern=better, that may not be so (depends on the definition of "better" of course) even by most general definitions.

A third point I was trying to make was that a superior designer may be able to use older techniques (rather than than the most modern ones) and still obtain a products that is better overall than a rivals designer's product which does use more modern techniques but still falls short overall, as defined by the requirements of the product - this happens so often in industry it shouldn't be news.


In one of the largest (and generally regarded as one of the best) semiconductor companies on one chip designers were dealing with a problem - there was a clock input and the clock was getting too much jitter (a kind of noise for clock signals) due to power supply noise problems. A whole design team studied the problem and tried to form some compensators (very complex circuits, and had they done it it would unquestionably be "modern"), till another designer from a different team attended one of the meetings and said "why are you using a single-ended input, why don't you make a differential input clock". Now the technique he was talking about is a decades old technique, and that did the job pretty well at almost no cost - basically the modern design being attempted was incredibly stupid. But that happens.

In another product that came recently in the market (I can't disclose more) the "innovators" decided to change the signaling in a way nobody else does, because it causes severe EMI problems. They ended up with a "modern" system which is now giving major headaches.

[Aroy]

How about - Modern design is what the engineers churn out today. Outdated what they did in past. Modern need not be better or even high tech.

The "Straight 8" engines were developed between the two world wars. Most of them developed tremendous torque at very low RPM. In fact one manufacturer claimed that his 2 ton vehicle could be run in the top gear from start to its top speed! That would be the solution to our B2B traffic, and qualify as a most Modern Engine?

Then there is the case of disk brakes. They came before the drum brakes, so drum brakes were modern then. With time disk brakes have become modern.

Similarly the "Vapour Adsorption" refrigerator came first. In time the "Compressor Type" refrigeration became dominant. Today the most modern refrigeration systems are reverting back to the Vapour Adsorption technology, especially for large industrial use.

So which design is modern and which old (I would not say outdated)?

[vina]

Originally Posted by Aroy

...

So which design is modern and which old (I would not say outdated)?

I think it may be a little easier to agree on what can be called "outdated" - hitherto the thread has focused only on the "modern" part of the subject.

I think we can define something as "outdated" without ambiguity if new techniques, designs or systems are available which beat that something on every significant parameter (including cost/reliability/environmental impact etc. but excluding parameters that are no longer relevant and will not be relevant for any foreseeable future applications)

[dkaile]

I have seen outdated engines like that on the Qualis outlast many of it's owners...

[DerAlte]

@vina came close, and I think @sutripta even more so - the words "Modern" and "Outdated" have little bearing on the design objectives / achievements. Had little bearing, to be more precise, since the engine design and testing start a good 5-6 years before the general enthusiasts (and journos) ever get to hear of it. Public, even later if at all. If they do, as @vina pointed out - it is more likely due to a marketing gimmick.

So, is that period contributing to it being modern or outdated? Neither, I guess.

Top priorities 3 are always emissions, efficiency (mileage-centric or power-centric) and cost - in that order. The gestation period usually matches that of the lead time given to the industry to match emission standards.

But yes, @ss_traveller, one has to go along with the emotional value of the 2 words you pointed out, since buying decisions are usually more emotional than rational. And one has to wonder about the engines like the Bollywood actors - is Farhan Akhtar modern or Shahrukh Khan outdated???