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edlithgow
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PostSubject: NeoChoke1   Thu Apr 07, 2016 5:54 am

Before I bit the bullet and took my carb apart, I tried using gas to get it to idle. As well as being a crude work-around for my current problem, this could address general issues with fuel dilution on startup, and MIGHT be usable as a performance booster with a diesel. (See "Can I turbo a car the bangernomics way" thread)

Model 1 off

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Model 1 on

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That volume of gas probably isn't going to make much difference to a car (though I have a 125cc motorcycle...?) so now I'll have to scale it up a bit.

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I knew it needed scaled-up, but I tried it on the car anyway.

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I decided to leave the clips and wing nut off so an explosion was "only supposed to blow the blahdy lid orf".

It wasn't running at all well and I thought it probably needed the carb stripped and cleaned, which I was putting off. It started on the lighter if it was left long enough (gas probably pools in the intake) but then needed accelerator to keep it going. I suspected the idle circuit was blocked, so expecting it to actually run on a disposable lighter was a bit unrealistic.

VERY unrealistic if the sums I belatedly attempted are correct-ish

1 volume of n-Butane requires 6.5 volumes of Oxygen

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air is 21% oxygen (say 20%)

1L engine at 1000 rpm.

4 stroke so its pumping 0.25% of its capacity/rev ie 250mls.

So in a minute it shifts 250X1000 mls of air

i.e. 250 litres

a fifth of that is oxygen, ie 50L

So stochiometric combustion requires 50X1/6.5 L of butane a minute.

7.692 litres of butane

Model 1a delivers 11cc in 20 seconds, so 33cc in a minute.

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so it needs scaled up by a factor of 769/33, or 233X

Motorcycle only needs scaled up by 29X, and its idle circuit isn't blocked (or wasn't last I checked) so it doesn't need to actually run on it. I havn't calculated required volume to richen it though, (maybe 10% enrichment) so maybe only 3X, which does seem potentially attainable with lighters or small torch, with a bit of trial and error.


Going "live" on the car, I mated my brake bleeding enema syringe (Mityvac my arse..er..as it were) to a gas blowtorch, more or less closing the rear off with wadded plastic bag.

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Running a bit of rubber tube (couldn't find the more rigid PVC brake-bleeding tube, which would have been better) into the air intake and turning the torch on full, it would idle by itself, which it wouldn't before.

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Couldn't get the bonnet closed though, and the starter solenoid contacts were just underneath the cylinder, resulting in some substantial sparks. (Hmm...shorting with a gas canister...good plan)

So I moved it to the front bumper, where it helped me limp the car home.

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However, ALL vehicle modifications are illegal in Taiwan, and thats not a very discrete one, so that concludes this round of testing. I'm stripping and cleaning the carb, so the car may never run again.
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Justwatching
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PostSubject: Re: NeoChoke1   Fri Apr 08, 2016 12:41 pm

I've been a week into the future and this is what you posted...


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edlithgow
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PostSubject: Re: NeoChoke1   Sat Apr 09, 2016 4:39 am

Pshaw.

Let me explain what I mean by that. Look at any internyet discussion of say, hydrogen as a fuel, and someone will always bang on (no pun intended) about how horribly dangerous it is, yet they have no problem at all with petrol, which is MUCH, MUCH more dangerous, but more familiar.

An extreme example is over on...you guessed it...the good old Honest John forum, where people SEEM to be trying to tell me that using brake fluid to clean a carburettor is a fire risk (?!).

I wasn't going to post NeoChoke on there because it seemed a bit close to trolling, but the bollocks about the brake fluid (or maybe De Debil) made me do it.

No reaction yet. Perhaps they've choked.

Course all that said, accidents can still happen.


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Justwatching
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PostSubject: Re: NeoChoke1   Sat Apr 09, 2016 8:39 pm

By what standard is petrol considered "MUCH, MUCH more dangerous"? Thought hydrogen was more combustible.

Petrol delivery is controllable from inside the vehicle. Your giant lighter system isn't. The petrol tank doesn't sit on top of the engine. Your giant lighter system does.

Safety isn't the only reason the idea is a bust. Your prototype system delivers inadequate volume. Up-scaling would make it prohibitively bulky and awkward to use. Also, it will require frequent replenishment, which I could phrase as either an ergonomics concern, or an economic one.

The whole premise is about plastering over a fault rather than addressing the underlying cause. IMO you'd be better off pursuing the cause not the symptom.

Don't imagine your insurer would be impressed either.
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Justwatching
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PostSubject: Re: NeoChoke1   Sat Apr 09, 2016 8:44 pm

Btw, when you say all modifications are illegal, do you mean it literally? Like aftermarket wheels and everything? Or just mechanical mods?
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edlithgow
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PostSubject: Re: NeoChoke1   Sun Apr 10, 2016 1:45 am

Justwatching wrote:
By what standard is petrol considered "MUCH, MUCH more dangerous"? Thought hydrogen was more combustible.

By any reasonable standard (of which my own standard is of course a shining example). Its a liquid, so leaks lurk, but its vapour is denser than air, so it tracks downhill.

Its no coincidence that the main ingredient of napalm is petrol. Napalm is known to be dangerous from extensive 20th century combat experience.

Some gases can pool too of course, which is a particular hazard on boats, but its no coincidence that petrol engines are not much used on boats either.

Hydrogen is lighter than air so disperses upward very quickly, especially if its burning. IIRC about half the passengers and crew survived the Hindenberg disaster.

My general point was the difference in perception of danger and reality when comparing fuel types. You seem to share this mis-perception.

Most of your criticisms of the half-assed prototype/workaround in NeoChoke1 are because its a half-assed prototype/workaround, which is fully acknowledged in the post, which also quite clearly states that I am "pursuing the cause not the symptom" (see "The Snake Pit" post), so that advice seems rather redundant.

That said, considered purely as a choke substitute, it potentially offers some advantages. In that role, the volume of gas required is much smaller and the economic/ergonomic pain therefore much less.

Justwatching wrote:
. The petrol tank doesn't sit on top of the engine. Your giant lighter system does.

Most motorcycle petrol tanks sit directly above the engine.

IF I actually implement this idea as a long-term fitment, its most likely to be as a choke substitute on my 4-stroke motorcycle. I wont do it on the 2-stroke because a gas-filled crank-case doesn't seem a great idea, though they already have a petrol-vapour-filled crank-case and they don't seem to explode all that often.

I havn't actually used (or got) a giant lighter. For driving, as is very clear in the post, the blowtorch was mounted on the front bumper. Any leakage is likely to fall clear. In particular, since the air intake pipe has an upward curve, if the engine stalls, the gas wont accumulate.

Justwatching wrote:
Don't imagine your insurer would be impressed either.

No S**t. Do you think it might be a good idea not to tell them then? Especially as they wouldn't have the faintest idea what I was talking about?

Yes, absolutely ANY modification is illegal. This saves them having to think/use judgement, which is a hassle. Of course enforcement is a hassle too, so you can get away with stuff.
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PostSubject: Re: NeoChoke1   Sun Apr 10, 2016 11:51 am

edlithgow wrote:
By any reasonable standard (of which my own standard is of course a shining example).

How about energy density as a reasonable standard? 120 mj/kg for hydrogen vs. 44.4 mj/kg for petrol. What about the ignition energy required to start a reaction? 0.017 mj for hydrogen vs. 0.24 mj for petrol.

Also, hydrogen is colourless and odorless, meaning system leaks/malfunctions are unlikely to be detected. Surely that factors into the equation, too.

edlithgow wrote:
Its no coincidence that the main ingredient of napalm is petrol. Napalm is known to be dangerous from extensive 20th century combat experience.

Petrol was likely selected due to its liquid state, cheapness and availability, not because it was the ultimate choice.  

edlithgow wrote:
Some gases can pool too of course, which is a particular hazard on boats, but its no coincidence that petrol engines are not much used on boats either.

Diesel vapor would pool just like petrol vapor, wouldn't it? Thought diesels were preferred because engine longevity and fuel economy were more important to marine applications than high rpm and power output, not because of safety.  

edlithgow wrote:
I am "pursuing the cause not the symptom" (see "The Snake Pit" post), so that advice seems rather redundant.

It also makes your neochoke redundant.

edlithgow wrote:
Most motorcycle petrol tanks sit directly above the engine.

Touché

edlithgow wrote:
No S**t. Do you think it might be a good idea not to tell them then?

Do you think it might be a good idea not to do it then? If your car is involved in wreck and they find your neochoke in the engine bay, telling them or not will be academic at that point.
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PostSubject: Re: NeoChoke1   Mon Apr 11, 2016 11:41 am

Justwatching wrote:
edlithgow wrote:
By any reasonable standard (of which my own standard is of course a shining example).

How about energy density as a reasonable standard? 120 mj/kg for hydrogen vs. 44.4 mj/kg for petrol. What about the ignition energy required to start a reaction? 0.017 mj for hydrogen vs. 0.24 mj for petrol.

Also, hydrogen is colourless and odorless, meaning system leaks/malfunctions are unlikely to be detected. Surely that factors into the equation, too.


IMO, (and, IIRC, the opinion of various "official" investigations, including a Skunkworks project investigating a hydrogen fuelled aircraft as a U2 replacement) far outweighed by the factors I mention.

Justwatching wrote:

edlithgow wrote:
Its no coincidence that the main ingredient of napalm is petrol. Napalm is known to be dangerous from extensive 20th century combat experience.

Petrol was likely selected due to its liquid state, cheapness and availability, not because it was the ultimate choice.


Weapons are not usually selected primarily on the basis of cheapness, especially by the US, perhaps the main user of napalm in the 20th century.

A typical Vietnam era "nape scrape" would involve a hazardous high speed extremely low level pass by something very expensive, like a Phantom 2, crewed by a couple of similarly expensive airmen. You really think in that context they were looking for the cheapest stuff they could find?

I'd bet petrol (thickened with polystyrene and no doubt other stuff) was selected because it was the nastiest stuff they could find. If there'd been anything nastier available they would have used it unless it was very, very expensive or had other drawbacks.

These days, of course, close air support is delivered from the safety of a high altitude B52 (or equivalent) or by drone, and they could probably contract it out to FEDEX, but it wasn't always thus.

Justwatching wrote:

edlithgow wrote:
Some gases can pool too of course, which is a particular hazard on boats, but its no coincidence that petrol engines are not much used on boats either.

Diesel vapor would pool just like petrol vapor, wouldn't it? Thought diesels were preferred because engine longevity and fuel economy were more important to marine applications than high rpm and power output, not because of safety.  

Engine longevity and fuel economy matter little for users of auxilliary engines in sailboats, since these engines are run very little, yet they are overwhelmingly diesels. Classic craft are sometimes found with petrol inboard engines (For example Stuart Turner 2-strokes) but they are often replaced while perfectly servicable, because people don't like being blown up.

Justwatching wrote:

edlithgow wrote:
I am "pursuing the cause not the symptom" (see "The Snake Pit" post), so that advice seems rather redundant.

It also makes your neochoke redundant.

I needed to move the car before I could work on it. Getting it to idle on gas allowed me to do that. It was a temporary workaround to a problem.

This is different to replacing the choke function with gas, which remains a possible future objective even with a fully-functional car (though I'm more likely to do it with the motorcycle)

Justwatching wrote:

edlithgow wrote:
No S**t. Do you think it might be a good idea not to tell them then?

Do you think it might be a good idea not to do it then? If your car is involved in wreck and they find your neochoke in the engine bay, telling them or not will be academic at that point.

Well, I've no experience with Taiwan accident investigation, but, given the way most things are done here, I wouldn't bet on them noticing it.

The legal minimum insurance cover (which is what I have, since I drive so little) wouldn't be recognisable as insurance in the UK, and is more akin to a govt-mandated accident compensation scheme. In that context, I'll take my chances.
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