[Sutripta]

Originally Posted by DerAlte

That has already been taken care of in the first few cm after the jet in carb engine. No effect by the time it reaches cylinder. Even in GDI it hardly has any effect in the cylinder.
It is now a cold charge.

For what?
Equilibrium.

In the end it all boils down to actual time available for cooling or heating - duty cycle is an abstraction.
Far more than an abstraction. If the freq of the stimulus is far higher than the observable change in the result, it saves you from a whole lot of (sometimes very) complex mathematics. I think in todays IT/ electronics dominated age, should have called it PWM!

PS: Sutripta - we are seriously OT wrt the thread title. Shouldn't we move all the OT stuff to a new thread?
I agree. But you are the Mod!

Originally Posted by SS-Traveller

...and this is what I found additionally. Does this apply to all cars, or just Hyundai?

I find that quoted explanation very iffy. First, it is a turbocharged petrol. Secondly think why our old faithful Ambassadors would vent blue smoke when we suddenly snapped the throttle shut. (Actually, Ive seen this even more in Omnis on restart)

Originally Posted by SPIKE ARRESTOR

PS- @Nitrogary, Sutripta, SS da, can we have a separate thread on calibrations? Would be a good topic for discussion.

Hi Spike, a very warm welcome!

Originally Posted by SS-Traveller

Maintenant, quel professeur devrais-je croire?

Keep the faith (in yourself) and to thyself be true. Don't believe (blindly) false prophets, sorry professors (false or otherwise). Question everything!

Regards
Sutripta

[DerAlte]

Originally Posted by SS-Traveller

... Maintenant, quel professeur devrais-je croire?

Vous devez croire seulemant Le Professeur, parce que - malheureusement - je ne suis pas!

Originally Posted by SS-Traveller

... With an increase in crankcase pressure ...

Full OHT - how? what caused it?

[SS-Traveller]

Originally Posted by SS-Traveller

With an increase in crankcase pressure...

Originally Posted by Sutripta

...think why our old faithful Ambassadors would vent blue smoke when we suddenly snapped the throttle shut. (Actually, Ive seen this even more in Omnis on restart)

Simple question, Sutripta, and a reasonably simple answer, I think, but I'll leave it to you to answer. It will also answer...

Originally Posted by DerAlte

...how? what caused it?

...but...

Originally Posted by DerAlte

Full OHT

= Oral Hydration Therapy?

[Sutripta]

Originally Posted by DerAlte

Vous devez croire seulemant Le Professeur, parce que - malheureusement - je ne suis pas!

Heureusement - je ne suis pas!
Guys, could we lay off this on a public forum.

Originally Posted by SS-Traveller

Simple question, Sutripta, and a reasonably simple answer, I think, but I'll leave it to you to answer. It will also answer...

...but...

= Oral Hydration Therapy?

But do you agree?

Regards
Sutripta

[SS-Traveller]

Originally Posted by Sutripta

But do you agree?

About blue smoke from the tailpipe on an overrunning engine in Ambys and Omnis? Absolutely. But I'd like you to put the answer about the why here in your own words.

[DerAlte]

Originally Posted by SS-Traveller

... = Oral Hydration Therapy? ...

No, OHT = Over Head Transmission (went over the head)! Needs Oral Re-hydration anyhow after that.

Originally Posted by Sutripta

Heureusement - je ne suis pas aussi!

Mais non, je ne crois pas que, monsieur!

Originally Posted by Sutripta

Guys, could we lay off this on a public forum.?...

D'accord. But, no fun when done off the forum, non?

[DerAlte]

Originally Posted by Sutripta

... Far more than an abstraction. ...

An abstraction, nevertheless. Once a phenomenon has been abstracted, anything beyond is still abstraction, not a reversible process to relate to the details.

Originally Posted by Sutripta

... I think in todays IT/ electronics dominated age, should have called it PWM! ...

Inappropriate simile / example. PWM can be / is deliberately controlled (modulation, thereby controlling the controlled element / system - like heater on/off -> oven temperature). In your use case, equilibrium temperature of cylinder innards is a result of (not directly controllable) variable conditions.

Achieving deterministic results (like preventing burnout) in such variable conditions is by human "do's and don'ts" - to be ignored at one's own peril. Much before that, the system is actually overdesigned - a measure of how much the human can ignore before there is a catastrophic failure. Dr. Porsche and his team worked towards reducing overdesign without compromizing system reliability.

Originally Posted by Sutripta

... Re: the actual thread starters problem, the best answers will come from the ECU coders (as to what has been done) and from their seniors as to why that has been done. ...

Principle of Management by Exclusion.

[Sutripta]

Originally Posted by SS-Traveller

But I'd like you to put the answer about the why here in your own words.

OK. Here goes. (Like all good disinformation pieces, it will be based on truths, halftruths, lies, speculation, ...)
One of the most difficult to lubricate systems in a OHV/ OHC IC engine is the valvegear. Because that which will be adequate at low speeds will overlubricate at higher speeds.
An overrunning engine with throttle snapped shut generates pretty high vacuum, greatly increasing the drawing in of lube oil/ vapours. In a turbocharged engine, the pressue diff between WOT and throttle snapped shut will be even more. And I would think lubrication would be more than the NA case.

Originally Posted by DerAlte

No fun when done off the forum, non?

OK, lets continue with the fun and games. As long as people don't charge us for impersonation!

Regards
Sutripta

[SS-Traveller]

Originally Posted by DerAlte

No, OHT = Over Head Transmission (went over the head)! Needs Oral Re-hydration anyhow after that.
D'accord. But, no fun when done off the forum, non?

Off-public-forum or on, it's always great fun! Bring on the splash lube and let's all rehydrate.

Originally Posted by DerAlte

...the system is actually overdesigned - a measure of how much the human can ignore before there is a catastrophic failure. Dr. Porsche and his team worked towards reducing overdesign without compromizing system reliability.

System reliability, catastrophic failure, overdesigning of systems... somewhere along the way, I think we lost newbie BHPian lambdaplus, whose not-so-complicated query was about whether his Fiesta (and other cars) show a jump in RPM when shifting gears, is normal or not.

Originally Posted by lambdaplus

...noticed something while driving...
Whenever you shift gears, the rpm goes a bit high!
I mean:
You are at 1300 rpm and press clutch (to change,say, from 1st to 2nd), the rpm goes to 1400-1500 rpm while you are changing!

Advantage:
You don't loose torque while gear shifts. You have revved your car to 2000 rpm and you change gears so that you can achieve higher speeds.
I'm not sure how much of a plus this is quantitatively, but it certainly it gives a good feeling while drive!

@Lambdaplus: Stop laughing your head off silently! You're the person to answer your own query, and since your Occupation: Automotive Engineer @ Bosch was missed by us all, why don't you now come forward and tell us? As Sutripta said,

Originally Posted by Sutripta

Re: the actual thread starters problem, the best answers will come from the ECU coders (as to what has been done) and from their seniors as to why that has been done. Anything mysterious, you can blame on 'these newfangled emission c**p.'

[DerAlte]

Originally Posted by Sutripta

... generates pretty high vacuum, greatly increasing the drawing in of lube oil/ vapours. In a turbocharged engine, ... even more. And I would think lubrication would be more than the NA case. ...

Knew as much, but didn't want to talk as I am not an engine-vengine type. Was stumped by the "pressure is higher in crankcase" - yes it is, but only numerically correct, not logic. In overrun, the work that is done on the pistons (momentum -> energy transfer via transmission; wouldn't happen if not in gear) causes the relative vacuum in the cylinder, which pulls lube vapours through the gaps in the rings.

In a TC engine, vacuum would be lesser - higher manifold pressure than non-TC - isn't it?

Originally Posted by SS-Traveller

... somewhere along the way, I think we lost newbie BHPian lambdaplus, ...

That was my reference to we being seriously OT. I will move out the OT posts to another thread.

Originally Posted by SS-Traveller

... @Lambdaplus: ... answer your own query, ...

a. non-Bosch injection in Fiesta b. Lambdaplus dare not talk about Bosch injection and c. quite likely he wouldn't have been allowed anywhere near by the system.

@Lambdaplus, you can do a lot without revealing, but that would need you to take interest personally and visit the test labs (or use the simulator).

[SS-Traveller]

Originally Posted by DerAlte

(I am not an engine-vengine person)...

Originally Posted by DerAlte

...I am not an engine-vengine type.

Could you elaborate further on this ?

Originally Posted by DerAlte

In a TC engine, vacuum would be lesser - higher manifold pressure than non-TC - isn't it?

Why should the turbo reduce vacuum inside the induction manifold with the throttle valve closed (petrol engine)? Isn't the turbo supposed to breathe more air into the induction manifold 'distal' to the throttle valve? Once the throttle valve closes, the turbo cannot pump any more air into the manifold any more than atmospheric air can get in. Different scenario in a diesel intake manifold though, I think.

Originally Posted by DerAlte

That was my reference to we being seriously OT. I will move out the OT posts to another thread.

Let's get lambdaplus's opinion first. I suppose he may not agree!

Originally Posted by DerAlte

a. non-Bosch injection in Fiesta b. Lambdaplus dare not talk about Bosch injection and c. quite likely he wouldn't have been allowed anywhere near by the system.

OHT. I thought he is an automotive engineer.

[DerAlte]

Originally Posted by SS-Traveller

Could you elaborate further on this ? ...

Colloquial phrase on TBHP for all who focus on engine & mechanicals, i.e. all who are not ICE, tyre, detailing, etc.!

Originally Posted by SS-Traveller

... Isn't the turbo supposed to breathe more air ...

Oooo medical term - 'distal'! Turbo 'blows' more air - it is the engine which is breathing and wheezing!. More air = more pressure, isn't it? So, if in the induction / suction stroke more air went in, at the BDC pressure is higher in the cylinder (relative to NA)? Beyond the next TDC (end of compression stroke, no fuel involved so no firing before TDC), when - in overrun - the piston is being drawn back there is still relative higher pressure? Higher pressure = lesser vaccuum?

Originally Posted by SS-Traveller

... I thought he is an automotive engineer.

Of course he is an automotive engineer. But that, mon ami, due to the qaida-kanoon in some companies, neither means universal accessibility to information / knowledge (work constrained to limited function), nor leave and license to disseminate the same. That is why my suggestion - personal interest / passion; that is the only way to go beyond constraints.

[SS-Traveller]

Originally Posted by DerAlte

Colloquial phrase on TBHP for all who focus on engine & mechanicals, i.e. all who are not ICE, tyre, detailing, etc.!

Understood. Engines are your Achilles' heel while ICE, tyre and detailing are your forte.

Originally Posted by DerAlte

Oooo medical term - 'distal'!

Dozens of terms, from 'nose' to 'tail', 'injection' to 'shoulder', heck, even 'nuts' - the medics knew them first before the engineer-vengineer did.

Originally Posted by DerAlte

Turbo 'blows' more air - it is the engine which is breathing and wheezing!.

The turbo blows when the revs are high, and softly breathes out when idling. Relative expression. Medics do understand blowing out to be exhalation too, esp. where those millions-of-years-old models are concerned. Even engines sound asthmatic, don't they? It's all about GIGO (gas-in, gas-out). Lo.

Originally Posted by DerAlte

More air = more pressure, isn't it? So, if in the induction / suction stroke more air went in, at the BDC pressure is higher in the cylinder (relative to NA)? Beyond the next TDC (end of compression stroke, no fuel involved so no firing before TDC), when - in overrun - the piston is being drawn back there is still relative higher pressure? Higher pressure = lesser vaccuum?

True - for the first few revolutions of the engine after throttle closure. As the throttle snaps shut, the turbo has already boosted the pressure inside the intake manifold, but cannot boost any further (manifold sealed off from turbo by throttle valve) ==>> inlet stroke of each cylinder takes in the air at higher pressure ==>> cylinder goes through the cycle (I-C-P-E) ==>> pumps out air into exhaust manifold ==>> pressure in intake manifold reduces with each revolution ==>> partial vacuum ==>> sucks out oil past valve guides and oil control rings ==>> increased emissions. Keep the throttle slightly open by ECU control even though the accelerator pedal is 'off', and emissions reduce.

Originally Posted by DerAlte

Of course he is an automotive engineer. But that, mon ami, due to the qaida-kanoon in some companies, neither means universal accessibility to information / knowledge (work constrained to limited function)...

OMG. Managers, rules, for-your-eyes-only secret files, need-to-know information... What do engineers learn in engineering colleges?

[DerAlte]

Originally Posted by SS-Traveller

Understood. Engines are your Achilles' heel while ICE, tyre and detailing are your forte.

Incorrect. Engines are not my Achilles heel - just that I don't focus on them (any more). And I am not into tyre and detailing.

Originally Posted by SS-Traveller

... (manifold sealed off from turbo by throttle valve) ==>> inlet stroke of each cylinder takes in the air at higher pressure ==>> cylinder goes through the cycle (I-C-P-E) ==>> pumps out air into exhaust manifold ==>> pressure in intake manifold reduces with each revolution ==>> partial vacuum ==>> sucks out oil past valve guides and oil control rings ==>> increased emissions. Keep the throttle slightly open by ECU control even though the accelerator pedal is 'off', and emissions reduce.

A-ha, appadiya?
1. ECU cannot hold the throttle open - there is no actuator, only a sensor there. Putting an actuator can be catastropic. Also, throttle doesn't seal - there is a minimum flow
2. So by your logic, there is generally no difference in the vaccuum between NA and TC engines? Throttle closes shut in either case

Originally Posted by SS-Traveller

... OMG. Managers, rules, for-your-eyes-only ... What do engineers learn in engineering colleges?

Jo tan laagi, so tan jaani! All that has a purpose / objective, and "method in madness" and all that.

Engg. College? Precious little of relevance to current practices and technology. The main reason why a new engineer straight out of college is not productively deployable. Completely different from Med - at least a new doctor is productive (not efficient or skillful - that takes time) straight away. Neither will he run away, nor will he kill the patient. That is something that one cannot be certain with Engg. (O bhai @lambda, please do not take offense - not a comment on your abilities).

[SS-Traveller]

Originally Posted by DerAlte

Engines are not my Achilles heel - just that I don't focus on them (any more).

Blurred engines? Progressive lenses recommended.

Originally Posted by DerAlte

A-ha, appadiya?

You're quite the linguist, Sir. Hercule Poirot and Sherlock Holmes would be put to shame.

Originally Posted by DerAlte

1. ECU cannot hold the throttle open - there is no actuator, only a sensor there.

And in drive-by-wire accelerator pedals?

Originally Posted by DerAlte

Putting an actuator can be catastropic.

How and why so?

Originally Posted by DerAlte

Also, throttle doesn't seal - there is a minimum flow

Can someone confirm that please? Carburettor throttles are 100% leakproof when new.

Originally Posted by DerAlte

2. So by your logic, there is generally no difference in the vaccuum between NA and TC engines? Throttle closes shut in either case

Non. Inferences being drawn, Sir, where none exist - it is certainly not my logic.

Originally Posted by DerAlte

Engg. College? Precious little of relevance to current practices and technology. The main reason why a new engineer straight out of college is not productively deployable. Completely different from Med - at least a new doctor is productive (not efficient or skillful - that takes time) straight away. Neither will he run away, nor will he kill the patient. That is something that one cannot be certain with Engg.

Very interesting & intuitive observation. An absolute eye-opener for me AFA engineering colleges are concerned.