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fly by wire throttle 
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TO220 - Visibile

Joined: Thu Jan 10, 2013 5:35 am
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TheRevva wrote:
. . .
I _must_ be missing something truly fundamental here.
I don't see the additional hardware costs as being prohibitively more than current engine technology (and as mentioned above, there are SOME savings that help to offset them!)
It all seems so easy that I cannot believe _someone_ hasn't already done it and it's about to reach mass production?

A decade ago, Vianney RABHi,
the inventor of the Variable Compression Ratio - VCRi - mechanism of the well known French company mce-5 (quote from mce-5 website: "Funds invested in MCE-5 R&D to 31 December 2011: 75 M€"),
was patenting / developing a cam-less hydraulic VVA (variable valve actuation) system.
From his communication with pattakon it seems that, among others, there were problems with the micro-alignment among the various cylinders epsecially at light load operation.
The cam-less hydraulic VVA project of Vianney Rabhi was rejected for some reason; then he focused on the rack-gear VCR of the mce-5. You can try to contact and ask him where the true problem was.

You can also make a search in the patent offices ( starting with the USPTO at http://patft.uspto.gov/ , for instance) to find-out what is the current state of the art in the cam-less hydraulic VVA systems and where the last applications / patents of this class are focused.

Thanks
Manousos Pattakos


Wed Jan 23, 2013 5:05 am
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1N4001 - Signed up

Joined: Thu May 29, 2008 1:23 am
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Location: Long Beach CA
jtw11 wrote:
Perhaps so far in our discussion there has been a misunderstanding in the definition of a 'closed' throttle. Certain I've been referring to a closed throttle to be idle throttle demand, not fully closed.

I suppose looking at the concept of a CLOSED, i.e. 0deg throttle, yes there are no pumping losses since we're not pumping past a throttle, but given we're talking about part load pumping losses at low throttle angles, that point is invalid.
That's the thing right there, that a fully closed throttle equals zero pumping losses.

But you're saying that opening the throttle a couple of degrees above fully closed will increase the pumping losses from zero to maximum. That losses start off at zero with the throttle fully closed, then increase to maximum as soon as the throttle starts opening. That fully closed is zero loss, and fully open is minimum loss.

jtw11 wrote:
Well here I'm afraid you're mistaken, since pressures are directly related to airflow - that's exactly what the lower loop of a pV diagram shows - as for the electrical analogy, I never think it works.
Put a voltmeter into the cigar lighter and try to measure current draw from the alternator. Or put a voltmeter into an AC receptacle and try to measure how much current the refrigerator is using.


Sun Feb 17, 2013 4:23 am
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This implies that you have a perfect seal in your perfectly closed throttle, and no other vacuum leaks such as idle valves, and brake boosters, and so forth. Even given that idealised situation, you've got imperfect ring seal, so you'll be pumping crank-case gas up past the rings if you manage to seal the intake manifold. Not to mention resonances in the last remaining molecules bouncing around in your incomplete vacuum causing movements of air, and thus friction, and thus loss. Certainly worth pondering :-)

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Sun Feb 17, 2013 12:27 pm
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TO92 - Vaguely active

Joined: Fri Mar 22, 2013 3:00 am
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I have a 2013 camry v6 with a fly-by-wire lag that the dealer says is natural. They say if I drive this 270HP car like a grandma I won't notice anything. What say you all? I think toyota needs to reprogram, or allow some odbII mod.
Thanks.


Fri Mar 22, 2013 3:30 am
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It's likely not really lag, it's much more likely to be nursing the transmission... I've written a PID throttle control system, and you can make it snap around faster than a real one, if you're careful.

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Fri Mar 22, 2013 3:44 pm
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TO92 - Vaguely active

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Please tell me more. The transmission seems to work fine. "I've written a PID throttle control system, and you can make it snap around faster than a real one, if you're careful"? I will interpret this as: I have written a PID code for throttle control. If you are careful, you can install this code (how??) and correct the problem. Is that what you are saying? If so, is there a way to download the current code, load yours up, and restore it for each scheduled service? Otherwise, it may void the warranty. How and why would it be the transmission?

Thanks.


Fri Mar 22, 2013 9:01 pm
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I say that I'd rather interface with a car than a computer to drive down the road. My latest "I'LL NEVER OWN A CAR WITH THAT!" is electronic roll mitigation. In other words they're purposefully disconnecting you from being able to steer the car, because big brother knows how far the wheels need to turn better than anyone else ever could.

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Fri Mar 22, 2013 10:44 pm
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Nope, I wrote that code for someone else, and you can't just take some code and merge it into an OEM ECU unless your name is Merp. My name is Fred. You've bought a modern car, get used to it, or trade it on something older and more sensible.

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Sat Mar 23, 2013 12:07 am
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TO92 - Vaguely active

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So this is an imposed philosophy that I will not get toyota to move off of right?


Sat Mar 23, 2013 5:59 am
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It tends to take entire communities to hack OEM stuff to the point of actual customisations. If you achieve that, more power to you. It's a LOT of work. Good luck.

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Sat Mar 23, 2013 6:07 pm
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