Turbos

[teredo]

There are indeed some very strange - even zany views on this forum, it is sometimes hard to take it seriously.
It's hard to credit that such simple mechanical matters can be a subject for argument when the facts are so well and widely established.

 

[macd]

Is there a single forced induction engine suitable for installation on small-to-medium sized yachts that uses anything other than a turbine-driven supercharger/turbocharger? If not, then teredo was being precious and the rest of you are wasting your time.

 

[Bobc]

Following on from my comment about not wanting an ECU, I've just read this on Nigel's forum:-

"Just thought it was worth sharing this experience. Been on Aquila last few days doing maintenance. I switch on the circuit breaker for the engine battery to double check the battery charge and after a few seconds heard the sound of 'ready to start alarm' on the EVC located at the helm. This of course should not be possible unless you push the ignition button on at the helm. When I went to the helm the fuel gauge was flicking between empty and fuel and the on/off ignition button failed to work on most occasions. All a bit odd.

I made enquiries with Volvo Penta and learnt the the EVC is feed by the IMD (ignition multi Diesel I think) which is located on the port side of the engine and consist of the intelligent part of the electric feed to the EVC. The IMD is the more expensive, circa £400 where as the EVC is £125. The IMD has a small fuse in the top which I was also able to check.

Fortunately for me I was able to get a new EVC and test that unit first of all. Simple plug and play, and thankfully it worked. The new EVC also has alarm/ dimmer to reduce brightness of techo etc. "

 

[pvb]

There are indeed some very strange - even zany views on this forum, it is sometimes hard to take it seriously.
It's hard to credit that such simple mechanical matters can be a subject for argument when the facts are so well and widely established.

You were happy to use Wikipedia as a source for authoritative (but irrelevant) information in post 48, so perhaps you'll also accept Wikipedia's opinion that "Common usage restricts the term supercharger to mechanically driven units.". See https://en.wikipedia.org/wiki/Supercharger

If you have difficulty taking this forum seriously, there are other forums...

 

[Skylark]

Ah .... I see that you didn't answer the question. Let's go past 10,000 hours and perhaps let's vary the revs up and down from idle. I'll ask again, which part, statistically, do you think is most likely to fail first? It's not a trick question .... just an engineering question.

Richard

Richard, I'm unable to answer your question because I don't have facts as a back up so anything I offer is pure conjecture. As an engineer, I don't like conjecture (otherwise known as a guess) unless it's an integral part of a hypothesis test. I have no reason whatsoever to think that the turbo will be first to fail, if that's what you're getting at?

A typical Weibull B10 life design target is 1 million miles but that's under a defined duty cycle.

Bear in mind that the engine maker would not accept fitting a major component like a turbo, a starter motor, a fuel pump or an alternator that didn't have "life of the vehicle" capability. I don't recall seeing a note in my car service book to "change turbo at 500,000 mile service" (unlike saildrive diaphragm, my sailing pet hate)

An important part of being an automotive tier 1 supplier, particularly to the commercial vehicle sector, is providing a remanufacture service. It's fairly common for engines to be replaced with a service exchange reman. The engine maker would typically tear down "dirty" engines and return major sub components to the manufacturer for reman. Good money can be made here. Tear down the turbo, clean, rebuild and replace consumables, re-warrant and resell. I don't have statistics to hand as I left the business 10 years ago, but few returns were scrapped due to being beyond economic repair.

What evidence do you have to support your views?

 

[duncan99210]

Supercharger - a device driven by gears that feeds compressed air to the engine.

Turbocharger - a device powers by a turbine in the exhaust gas flow that feeds compressed air to the engine......

 

[macd]

Supercharger - a device driven by gears that feeds compressed air to the engine.

Turbocharger - a device powers by a turbine in the exhaust gas flow that feeds compressed air to the engine......

No idea where those definitions came from, but they're not accurate and don't help. Teredo's is the pedantic view (i.e. that a turbocharger is just one variant on the supercharger), but taking any definition the mechanical drive for a supercharger can be by chain, belt, gears or directly from the crankshaft. Teredo suggests it could even be by a horse, but it'd need bloody long legs alongside our boat.

 

[Malo37]

No idea where those definitions came from, but they're not accurate and don't help. Teredo's is the pedantic view (i.e. that a turbocharger is just one variant on the supercharger), but taking any definition the mechanical drive for a supercharger can be by chain, belt, gears or directly from the crankshaft. Teredo suggests it could even be by a horse, but it'd need bloody long legs alongside our boat.

Duncan99210's definitions are precisely correct.
Below from the 'Engineering explained' website
What’s the difference? A supercharger is an air compressor driven by the crankshaft of an engine, usually connected with a belt. Alternatively, a turbocharger is simply an air compressor driven by an exhaust gas turbine. That’s the one key difference; a supercharger requires engine power to run, while a turbocharger runs off waste energy created by the engine.

 

[pvb]

That’s the one key difference; a supercharger requires engine power to run, while a turbocharger runs off waste energy created by the engine.

Hmmm, so constricting the exhaust by forcing it to drive a turbo doesn't consume any power?

I always thought the key difference was that superchargers work at all engine revs, whereas turbochargers generally work better at higher engine speeds. Hence the use by Mercedes of superchargers on their "Kompressor" models.

 

[Malo37]

Hmmm, so constricting the exhaust by forcing it to drive a turbo doesn't consume any power? Where does this assumption come from? Of course a turbocharger consumes power - but not as much as a supercharger.

I always thought the key difference was that superchargers work at all engine revs, whereas turbochargers generally work better at higher engine speeds. Hence the use by Mercedes of superchargers on their "Kompressor" models.

Generally correct. Hence my earlier statement in this silly thread that turbocharged engines do not like to be run on low load.

 

[Malo37]

There are indeed some very strange - even zany views on this forum, it is sometimes hard to take it seriously.
It's hard to credit that such simple mechanical matters can be a subject for argument when the facts are so well and widely established.

You could always contact the Institute of Mechanical Engineers to let them know they have been wrong on this one for the past 100 years or so.

 

[pvb]

Where does this assumption come from? Of course a turbocharger consumes power - but not as much as a supercharger.

From Malo37's post? Where he claimed a supercharger requires engine power, but a turbocharger magically runs on "waste energy".

 

[RichardS]

Richard, I'm unable to answer your question because I don't have facts as a back up so anything I offer is pure conjecture. As an engineer, I don't like conjecture (otherwise known as a guess) unless it's an integral part of a hypothesis test. I have no reason whatsoever to think that the turbo will be first to fail, if that's what you're getting at?

A typical Weibull B10 life design target is 1 million miles but that's under a defined duty cycle.

Bear in mind that the engine maker would not accept fitting a major component like a turbo, a starter motor, a fuel pump or an alternator that didn't have "life of the vehicle" capability. I don't recall seeing a note in my car service book to "change turbo at 500,000 mile service" (unlike saildrive diaphragm, my sailing pet hate)

An important part of being an automotive tier 1 supplier, particularly to the commercial vehicle sector, is providing a remanufacture service. It's fairly common for engines to be replaced with a service exchange reman. The engine maker would typically tear down "dirty" engines and return major sub components to the manufacturer for reman. Good money can be made here. Tear down the turbo, clean, rebuild and replace consumables, re-warrant and resell. I don't have statistics to hand as I left the business 10 years ago, but few returns were scrapped due to being beyond economic repair.

What evidence do you have to support your views?

That's a fair answer David. I don't have any scientific evidence either way but thought you might have some from within the industry.

My only evidence (I use the term loosely) is based on my personal experience of superchargers in the 1970s through to the days of turbochargers in the 1980s and 90s. My perception over those two decades was that superchargers were generally reliable provided you kept an eye on the belt, which was easy, and failure was generally benign but they were bulky whereas turbochargers were more compact but less reliable and failure was often difficult to predict and the failure mode could sometimes be disasterous and ruinously expensive. Even making sure that the bearings were replaced when necessary was quite labour-intensive.

From this early experience I have steered clear of turbos on the basis that, whatever the present-day statistics, it is an additional highly stressed part and if you can get the power/economy you need out of a normally aspirated engine then why complicate matters unnecessarily. As I do all my own work on all my cars as garage are generally useless, then it pays me to KISS.

I currently run a 1 litre 3 cylinder, a 2 litre 4 cylinder and a 4 litre 8 cylinder and each of these hits a precise performance/economy point depending upon the occasion which suits me perfectly so I have no wish to complicate matters with turbos or even blowers.

Richard

 

[NorthUp]

Quote:
"OK, maybe the white hot bit was a little ott but I'd be highly suspicious of a turbo that ran cool enough to retain a paint finish. If it's running that cool where's it getting it's energy from?

Wikipedia provided the table below and a bit of research suggests that commercial vehicular diesels typically run a max EGT at turbo inlet of up to 1200C but more commonly 900 - 1000C.

Paint ????? Wow! "

The worm has never come across a water cooled turbo? More wiki research required, I think!

 

[macd]

Duncan99210's definitions are precisely correct.
Below from the 'Engineering explained' website
A supercharger is an air compressor driven by the crankshaft of an engine, usually connected with a belt.
Alternatively, a turbocharger is simply an air compressor driven by an exhaust gas turbine. That’s the one key difference; a supercharger requires engine power to run, while a turbocharger runs off waste energy created by the engine.

...er, how is "a device driven by gears" a "precisely correct" description of "usually connected with a belt"?
And while you were being so very precise in comparing them, mightn't you also have mentioned boost lag and differences in low rpm performance. And don't get the idea that all the energy driving a turbo is 'free': some is lost the elevated exhaust back pressure.

None of which has much to do with the OP's question, so sorry.

 

[teredo]

Duncan99210's definitions are precisely correct.
Below from the 'Engineering explained' website
What’s the difference? A supercharger is an air compressor driven by the crankshaft of an engine, usually connected with a belt. Alternatively, a turbocharger is simply an air compressor driven by an exhaust gas turbine. That’s the one key difference; a supercharger requires engine power to run, while a turbocharger runs off waste energy created by the engine.

Malo., Duncan. I'm sorry, I accept that you guys seem to speak fluent Vauxhall Astra marketing-guff and do not understand plain English but this does not make you correct. That statement is COMPLETELY and UTTERLY incorrect. Why is it hard for you to look in a dictionary? Why can you not understand the basic language of English? Super = extra, additional. Are there too many syllables there for you? Charge is the fuel-air mixture taken by an engine. Is this concept understood? This "Super" and "Charger" is something that adds extra charge.

It matters not whether you power it by a turbine, a belt, a drive shaft, a divergent duct or a bloody great hamster wheel; the device is a SUPERCHARGER! That is the generic term for the device. Christ! This is so terribly, terribly basic!
If you drive it with a turbine then it is called a turbo charger or a turbo supercharger, both mean the same. If you drive it with a belt, shaft, gears it is a mechanically driven supercharger. God knows what the hamster variety is called but the electric one is - guess what???? called an electric supercharger. Go figure... But they are ALL superchargers.

All engines with forced induction are "supercharged" I do not know how you can argue against that unless you live in a different universe to the rest of us. The type of supercharging may or may not add to the understanding of the system but the way you are arguing is like saying that an Electrolux is a Hoover but not a vacuum cleaner.

Is this a forum where simple technical matters are widely ridiculed? Seems an extraordinary approach for people in a technical hobby.

 

[RichardS]

Malo., Duncan. I'm sorry, I accept that you guys seem to speak fluent Vauxhall Astra marketing-guff and do not understand plain English but this does not make you correct. That statement is COMPLETELY and UTTERLY incorrect. Why is it hard for you to look in a dictionary? Why can you not understand the basic language of English? Super = extra, additional. Are there too many syllables there for you? Charge is the fuel-air mixture taken by an engine. Is this concept understood? This "Super" and "Charger" is something that adds extra charge.

It matters not whether you power it by a turbine, a belt, a drive shaft, a divergent duct or a bloody great hamster wheel; the device is a SUPERCHARGER! That is the generic term for the device. Christ! This is so terribly, terribly basic!
If you drive it with a turbine then it is called a turbo charger or a turbo supercharger, both mean the same. If you drive it with a belt, shaft, gears it is a mechanically driven supercharger. God knows what the hamster variety is called but the electric one is - guess what???? called an electric supercharger. Go figure... But they are ALL superchargers.

All engines with forced induction are "supercharged" I do not know how you can argue against that unless you live in a different universe to the rest of us. The type of supercharging may or may not add to the understanding of the system but the way you are arguing is like saying that an Electrolux is a Hoover but not a vacuum cleaner.

Is this a forum where simple technical matters are widely ridiculed? Seems an extraordinary approach for people in a technical hobby.

See post #57 again if you need reminding about why your approach is self-defeating.

Richard

 

[sailorman]

A supercharger is a compressor
a turbocharger is a centrifugal device

 

[macd]

A supercharger is a compressor
a turbocharger is a centrifugal device

Some superchargers are centrifugal devices
All turbochargers compress
So does my laptop
ASUS makes great turbochargers

 

[davidej]

Malo., Duncan. I'm sorry, I accept that you guys seem to speak fluent Vauxhall Astra marketing-guff and do not understand plain English but this does not make you correct. That statement is COMPLETELY and UTTERLY incorrect. Why is it hard for you to look in a dictionary? Why can you not understand the basic language of English? Super = extra, additional. Are there too many syllables there for you? Charge is the fuel-air mixture taken by an engine. Is this concept understood? This "Super" and "Charger" is something that adds extra charge.

It matters not whether you power it by a turbine, a belt, a drive shaft, a divergent duct or a bloody great hamster wheel; the device is a SUPERCHARGER! That is the generic term for the device. Christ! This is so terribly, terribly basic!
If you drive it with a turbine then it is called a turbo charger or a turbo supercharger, both mean the same. If you drive it with a belt, shaft, gears it is a mechanically driven supercharger. God knows what the hamster variety is called but the electric one is - guess what???? called an electric supercharger. Go figure... But they are ALL superchargers.

All engines with forced induction are "supercharged" I do not know how you can argue against that unless you live in a different universe to the rest of us. The type of supercharging may or may not add to the understanding of the system but the way you are arguing is like saying that an Electrolux is a Hoover but not a vacuum cleaner.

Is this a forum where simple technical matters are widely ridiculed? Seems an extraordinary approach for people in a technical hobby.

Teredo

Most of us agree that you may be 100.0000% technically correct, but in the modern parlance (call it Vauxhall marketing speak, if you want to) a turbo is something driven by exhaust gas while a supercharger is driven by the engine.

Obviously this is a bit of short-hand but everyone here understands what the others mean and trying to prove that you are so much clever than the rest of us is winning you no friends.

A word to the wise -"back off" and let the rest of us discuss the use of turbos in yacht engines