Alvin

iTrader: (2)

That is actually one of the most attractive things about electronically operated valves. With the TB open you can run down the road with a intake at a higher pressure.

You can also do things like have more square valve events. You can also close the intake valve extremely prematurely at part throttle so the rest of the intake stroke acts like a spring, loading up energy that you can for the most part reclaim on compression.

Also at part throttle you can open exhaust very close to BDC (while still closing at BDCexhaust). what would that do is make better use of the power stroke at low throttle.


I've also read that 42 volt systems could shed a significant amount of wieght in wiring. The problem is its edging on what can be considered dangerous.

JohnnyC

Great insight Alvin - the impact on the TB was not immediately obvious to me until I heard a few of you bring it up. Things really get interesting when you start talking about leaving the TB open while cruising down the road at low RPM's. The computer would control even more aspects of the engine, and the valves would no longer be slaves to a mechanical camshaft profile that cannot change. Emissions could also be greatly improved with less mechanical parts / systems.

Alvin

iTrader: (2)

Thanks,

Just think about it. ON your intake stroke your doing alot of work by moving the piston down with such a heavy vaccum on it. With electronically opened valves you can start your intake stroke, open your valve really quick while your expansion (volume) rate is high near TDC.. get your little shot of air and then close again. Since all the cylinders aren't fighting for a small piece of air in the intake, the manifold can remain at ATM.

You would be controlling cylinder filling with valve events instead of putting a HUGE restriction on the intake.. that being the throttle body.

Pwebbz28

iTrader: (31)

I THINK Acura did it first on the NSX. I could be mistaken though.

Richiec77

iTrader: (3)

Why not just run a full Solid-state switched electrical system? And it's DEFINITLY with-in the realm of possibility. There are companies out there making that exact product. My friend is buying one for his truck. So I'll have some experience 1st hand in a month or 2.

http://www.isqe.com/

Correct about the voltage increase decreases the current needed to be moved so the wiring is smaller.

48 volt's is barely a tingle. IT won't "Shock" you bad at all. Especially mechanics (dried out skin on their hands). If you want to try it out, go find your door-bell system in your house. That's a 48V DC system. It'll give a tiny shock. Some people like myself with dried out hands barelly feel it at all. For women, it's a tiny shock. (Women by study have lower resistance in their bodies)

I don't see it as being a real safty issue.


This has been discussed for years. I remember 1st reading about the change that "Needs" to be made to a 48V system back in 1995/96. Car Stereo people have been paying attention to this for years since the ability of the system is roughly 3-4x what's out there now.

1CAMWNDR

iTrader: (21)

Her ya go fellas. Check this **** out:
http://www.sturmanindustries.com

brad8266

iTrader: (23)

almost everything in the military is 24 volts.

brad8266

iTrader: (23)

48 volts is far from dangerous. You can put one hand on the - side and one on the + side of 48 volts and it aint gonna hurt you one bit. Ive been on about 70 VDC and its a small sensation, nothing thats going to hurt ya.

mcamp001

iTrader: (1)

I think most home doorbell/ thermostat systems are 24 volt, at least mine is

Richiec77

iTrader: (3)

You're right. I'm trying to figure out why I'm thinking Door bell systems are 48 volts? Maybe it's something else I was working with. Maybe HVAC systems? I dunno.

Stang's Bane

iTrader: (22)

There was talk a few years ago about using small electric ceramic magnets. I remember something about that

juiced_lt1

Nice find!

pianoprodigy

iTrader: (1)

Yeah, read about something like this a while back.

And on a side note, I played the piano for Penn State's Christmas Party on Christmas Eve (they're in town for Outback Bowl). I got to shake Joe's hand. Pretty cool.

BJM

iTrader: (1)

Camless engines are inevitable, we just need the kinks ironed out. About 10 years ago I read an article where a researcher used piezo-electric transducers to actuate valves on a single cylinder engine. The piezos have only a tiny stroke so it was rigged up with 20:1 rocker style arms to amplify the motion. The engine ran really well. The big problem was the engine produced about 5 kW while the "valve train" required 15 kW to operate. Power consumption of the camless valve train will take quite a while to improve even after the system is working well. Its not obvious how to efficiently operate a whole valve train electrically without expending a lot of power.

cantdrv65

iTrader: (3)

Its the added fat from the hooters.....

2002_Z28_Six_Speed

iTrader: (19)

Quote:

Originally Posted by brad8266

48 volts is far from dangerous. You can put one hand on the - side and one on the + side of 48 volts and it aint gonna hurt you one bit. Ive been on about 70 VDC and its a small sensation, nothing thats going to hurt ya.

1 volt acrost the heart could kill you. 33 volts is well more than enough to kill you given sufficient contact ie moist, salty skin. Skin only has high resistances in certain circumstances. Injuries or jumping in a bath tub change that!! You experienced brushed contact with current under dry skin circumstances. Don't get cocky. I pray you never see fatal conditions.

Quote:

Originally Posted by brad8266

um..ok. Have you ever got shocked my an electric oulet at home before?? Its not that bad. Thats 120V, 50 isnt anything compared to that.

HAHAHAHAHA Ever heard of RMS?

120VAC --> 84.85 VDC. That arguement is very misleading and from your reply it does sound like you didn't even give that thought. Don't play off electricity as a toy. AC is a sine wave so that higher voltage is overrated compared to a DC shock or the average voltage of AC over time.

By the way. You can experience low voltage/high current (short like condition) and high voltage/low current (open like condition) in your body from wet skin vs dry skin respectively. Do you honestly believe that it is still 120 Volts by the time it gets to your heart? AHAHAHAHA Ever heard of voltage divider? Guess not.

Measure from body to ground NOT source to ground. IN YOUR BODY. Look up Kichoff's Law for confirmation. Further, look up current controlled circuits. Your certificate only covers a tightly managed power system. Not the world of the possible. And that's "what I know about this electric."

-------------
Unrelated
-------------

I love it when people, mostly on the net, condone common knowledge and rub it off as unneeded intelligence or "book-smarts."

I understand that my revision to this post sounds smart allic, however, that is due to the conditions under which other people treated me despite I was diligent and mature with them at first. Text made small as off-topic.

brad8266

iTrader: (23)

um..ok. Have you ever got shocked my an electric oulet at home before?? Its not that bad. Thats 120V, 50 isnt anything compared to that.

fast98

iTrader: (16)

the new hybrid trucks from gm already have the 42 volt system, but only the starter/alternator assembly and the electric motor are on it, everything else is 12 vlts on the car

hammertime

iTrader: (1)

I thought it was the amperage that was most dangerous. At least for 12v/24v/48v dc and 110v/220v ac. Your skin shouldn't allow enough conduction, unless the current burns through the outer flesh.
from http://www.cdc.gov/niosh/elecovrv.html

tmod

Mercedes C-class debuts with this technology as a 2008 model.

http://paultan.org/archives/2005/07/...valve-engines/