Drive by Wire
Posted 20 January 2012 - 06:02 PM
Posted 22 January 2012 - 09:35 PM
Of course there is always the tunability, but how much do you really need to tune it. I mean, it would be nice to have the extra item to custom tune, but motion pro is basically doing that right now mechanically, anyway...
I guess im not going to go as far as to say its not a good idea. If the increase in tunability that the system creates is even a miniscule speed advantage, you will start seeing top tier teams starting to do it. In my honest opinion, if teams havent already atleast LOOKED into doing this, then they're lagging behind. But for the everyday rider, this is not going to be a system that creates any sort of advantage until the day that rotory potentiometer sensors or string potentiometer sensors, newly designed throttle tubes, and wiring, become less priced than a the current throttle tubes and current cables.
just my 2 cents...
Posted 22 January 2012 - 10:52 PM
Posted 23 January 2012 - 06:44 AM
I am getting old and cheap and I wouldn't want to see it happen. Too many bikes are crossing over technology gap while the simple trail/play/beginners bike are dropping off. F1 technology is great but how many privateers or weekend warriors do you see in a F1 car
Posted 23 January 2012 - 08:02 PM
Posted 23 January 2012 - 08:15 PM
Posted 23 January 2012 - 08:18 PM
Needless to say, nobody seems to be complaining about the sportbike throttle by wire system and having felt many of those throttles myself, the manufacturers seem to have it licked. I'm not sure of the delay yet, but its probably minimal as computers today are pretty fast. The nice thing about throttle by wire is the simple ability to manage tuning and allow the ECU to keep the throttle open for anti-stall and on 4 strokes, it helps keep the engine breaking to a minimal.
I think on 4 stroke dirt bikes, throttle by wire is only a matter of time. On 2 strokes, I don't think we'll ever see it.
Posted 25 January 2012 - 09:33 AM
Posted 25 January 2012 - 09:15 PM
Posted 26 January 2012 - 10:16 AM
Fuels that eliminate those limitations. Mostly. Still has to be gasoline, so that pretty much eliminates the idea of running 15:1.
There is, as I understand it, a rule against "traction control", although I think some teams are stretching that one pretty thin with some of the timing controls they are using. If the AMA decided fly-by-wire throttle control was traction control, it would be illegal, too.
Posted 26 January 2012 - 05:42 PM
Posted 26 January 2012 - 06:53 PM
Posted 26 January 2012 - 07:22 PM
Edited by 79yamdt, 03 February 2012 - 04:07 PM.
Posted 26 January 2012 - 07:23 PM
Electronic ignition control cannot control all of those things because it cannot control compression pressures.
Posted 27 January 2012 - 04:16 PM
Posted 03 February 2012 - 01:10 PM
Wouldn't the piston have to travel faster than the speed of sound to do that?
Overrun fuel cut has been a standard feature of digital EFI practically since the inception of digital EFI decades ago. Many cars equipped with it (EFI) don't use smog pumps, either. How does TBW eliminate the rich spike on throttle chop, though? The only thing I can think of that would truly eliminate that without incurring some kind of lag is GDI.
On the topic of traction control, it can be implemented without wheel speed sensors by monitoring changes in engine RPM. The ECU can limit output when engine RPM/time exceeds a threshold value. I doubt wheel speed sensors would easy to use on a bike anyway. Situations where the rear is not slipping and the front is off the ground, using throttle to control flight dynamics, and using throttle to steer the bike come to mind.
Posted 03 February 2012 - 02:20 PM
Yes they would, and no they don't, not even close. A 5.7 Chevy with 6 inch rods turning 9500 RPM will generate PEAK piston speeds in the realm of 9000 fpm, and sound in air moves at 66,986.22 fpm. The statement is ludicrous on its face anyway, since it is the pressure of the advancing flame against the piston that causes detonation in the first place. High RPM engines can utilize relatively low octane fuel if they avoid low speed operation. That simply elevates piston speed to the point that the piston moves fast enough to avert detonation in the first place. Good ignition controls can prevent that anyway.
Posted 03 February 2012 - 02:45 PM
drive by wire in no way affects turbo lag, let alone reduces it...
Posted 03 February 2012 - 03:40 PM
This is my understanding of it anyways as far as the saab Trionic 7 engine management system. Maybe other cars don't but I wouldn't see why other cars with drive by wire systems and turbos wouldn't have a engine management program that did this.
The Saab Trionic 7 (T7) engine management system in the 9-3 Viggen is controlled by a 32-bit microprocessor that is capable of performing two million calculations per second. It monitors and controls the direct ignition, fuel injection, turbo boost pressure and throttle setting to enhance engine performance and eliminate turbo lag. The system continually adjusts the calibrations to maximize engine performance - compensating for a number of variables including fuel quality, altitude and more.
Since T7 provides electronic throttle control, it overcomes the inertia present in a large turbocharger and eliminates turbo lag by manipulating the throttle position. It opens the throttle further than the driver has requested, making more engine torque available as soon as it's needed. It's an electronic slight of hand, but immediately accomplishes the driver's request for more power. All 2001 Saab models feature Trionic 7.
Borrowed from here.. http://saabworld.net...elease-usa-283/
Edited by 79yamdt, 03 February 2012 - 04:02 PM.
Posted 06 February 2012 - 03:04 PM
You do not need drive-by-wire to limit detonation because all modern bikes have a 3D programable spark advance system, and the EFI ones probably reference manifold pressure as well. There are two ways to control combustion pressure - throttle opening, and spark timing. Retard the timing and combustion pressures go down.
Most of the gains on modern vehicles are coming from variable valve timing, and far more precise fuel control from better air-flow sensors and wide-band oxygen sensors. Not drive-by-wire. Cams with lots of overlap make big power, but have poor low end torque, and quite poor emissions. Variable valve timing allows the use of very aggressive cam profiles, but during idle, low RPM, and cruise, they phase the camshaft timing apart to pretty much eliminate valve overlap, which grealy improves emissions. The main benifets of drive-by-wire are that it allows the computer much more control over engine power for things ilke traction control, and vehicle stability control, and during cruise it can cut the throttle blade opening slightly when the EGR opens, or the valve timing switches into EGR-like mode. I suspect it's mainly a traction and emissions thing in bikes as well.
Race engines were making 150HP/L well before the days of fuel injection, let alone drive-by-wire EFI. Even the carb'd 450s can be made to make 65HP at the wheel without too much effort, and still be quite rideable. That's 144HP/L from a single cylinder, carbureted engine.
Edited by Lead Head, 06 February 2012 - 03:05 PM.