Prius Shuts Down In Snow

<div class='quotetop'>QUOTE(jayman @ Feb 12 2007, 02:43 AM) [snapback]388762[/snapback]</div>

In your previous post you said it slipped an inch and stopped. The Ice ball must be wedged so not even that inch of turning will occur. And/or throttle usage must be very light so minimul torque is appled to the wedged tire, or the ice ball will just be crushed. This may not be a practical thing. But at 30 below, the ice can be very strong. It will depend on if the programming is directionally detecting. If the wheel has to move forward while the rear wheels do not, for the TC to turn on, it might work. If the wheels tracking each other triggers the TC, then it wont.

You could try it in your barn, with a hard piece of rubber, or a small tire as the wedge and the tire jacked up?

You know, a good Toyota implemented solution to this might just be a just be a Torsen axle. Check Out: http://www.torsen.com/files/Traction_Control_Article.pdf

 

<div class='quotetop'>QUOTE(donee @ Feb 11 2007, 09:34 PM) [snapback]388752[/snapback]</div>

Do you actually understand how application of a brake works in a traction control system?

As soon as the brake is applied, torque is transferred to the stationary wheel. How is that "allot" [sic] slower than the system you propose?

 

<div class='quotetop'>QUOTE(priusenvy @ Feb 12 2007, 08:47 AM) [snapback]388808[/snapback]</div>

Hi Priusenvy,

The electronics of the motor control can act faster than the solenoidal control of the hydraulic brake system.

 

<div class='quotetop'>QUOTE(donee @ Feb 12 2007, 08:00 AM) [snapback]388809[/snapback]</div>

That may be true, but it can't/doesn't apply any braking force.

 

<div class='quotetop'>QUOTE(Jonnycat26 @ Feb 12 2007, 09:43 AM) [snapback]388816[/snapback]</div>

Hi Johnycat. Not sure if the Prius is a 4-quadrant drive or not. But most likely it is, as it can do regeneration. In which case if it was in a electronic gearing mode, and slaved to the turning of the rear tire behind it, it may have to have negative torque applied when torque comes through the differential. This can be done with electronics readily. Or course, there would need to be a second MG2 inverter MG2L and MG2R .

 

<div class='quotetop'>QUOTE(donee @ Feb 12 2007, 02:09 AM) [snapback]388768[/snapback]</div>

Well, I'll try something like that at the hobby farm this weekend. What the hell, I have nothing to lose.

<div class='quotetop'>QUOTE(donee @ Feb 12 2007, 02:09 AM) [snapback]388768[/snapback]</div>

The Torsen is a very well respected traction control device. I just love all those worm gears inside. I've only met a few people who have actually had one installed, and they swear by them. Not only do they work just as well as a Detroit Locker, but they're not as harsh.

Somebody claimed that some Ford Ranger pickup trucks can be ordered with the Torsen in the rear axle. That would be a very nice option for winter driving.

<div class='quotetop'>QUOTE(donee @ Feb 12 2007, 01:27 PM) [snapback]388929[/snapback]</div>

There are speed sensors in the rear hubs, but that's just for ABS. The rear wheels are just "along for the ride." Take away the HSD, and the Prius is like every other front wheel drive car on the market. As far as regeneration, that only involves the front wheels.

You may be thinking of the Highlander Hybrid. The rear motor/generator is actually involved in regenerative braking. I was thinking of buying one, but to get side impact and head curtain airbags involves the Limited package, which in Canada is $53,600. That's around $9,000 more than the base Highlander Hybrid.

 

Jayman is quickly becoming my hero!

This was such a useful post and a good recount of a great experiment. I am interested in hearing about the results when you get multiple Prii together and see how they compare. Now I'm off to find your answers to me on a different thread about 20/50 weight oil. That issue still perplexes. Just like in the software biz, I think we can all learn that doubting the user can eventually make you look pretty darn stupid. Sure there are times when the user is wrong, but what do you have to loose by trusting their voracity? I agree that there is way too much user input about problems for this to be written off as user error. Toyota better be doing something real about this!


<div class='quotetop'>QUOTE(jayman @ Feb 11 2007, 11:57 PM) [snapback]388739[/snapback]</div>

 

What would really help is for a 2004 Prius and a 2006/2007 Prius side by side in the same snow conditions. I have a 2004 Prius that exhibits the extreme traction control and would gladly meet up with someone in the Southeast Minnesota region during the next snow storm. That would be a definitive test and we could even capture the results on video tape.

 

<div class='quotetop'>QUOTE(Tideland Prius @ Feb 12 2007, 03:12 PM) [snapback]388961[/snapback]</div>

Hi Tideland,

4 quadrant is a description of a motor drive (the electronics that control the motor). It has nothing to do with AWD, or 4WD, or any number of wheels that are driven. There are four quadrants of motor control , turning forward-torquing forward, turning backward-torquing forward, turning forward - torquing backward, turning backward-torquing backward.

A 4 quadrant motor drive can control the speed of the motor in the over-drive situation (where the load is negative and is trying to speed up the motor). It can do this in forward turning or reverse turning. Besides the normal situaition of powering the motor in both the forward and reverse directions.



<div class='quotetop'>QUOTE(jayman @ Feb 12 2007, 08:30 PM) [snapback]389175[/snapback]</div>

Hi Jayman,

Nope. I thinking of a complete redesign of the HSD front wheel drive system to have two MG2's. They might actually be hub mounted. This would provide for the ultimate in wheel control in a frontwheel drive car.

In slippery conditions, after slip is detected, the front drive wheel could through a four-quadrant control be slaved to the rolling action of the undriven rear wheel. When there is not synchrony between the two front wheels, torque would be transfered to the slipping wheel, which the four-quadrant drive would have to counter to keep the wheel in synchorony with the rear wheel on that side of the car.

 

Hi All,

First heavy snow travel day of the year here in Chicagoland. Heavy, at least by Chicagoland standards. The roads were rutted through to the concrete in some places, with about 7 inch mounds in the middle of the road. Its been snowing all day, lake-effect and a nor-easter style storm up from Texas. Was concerned about dragging on the middle lane snow mounds and loosing force on the wheels in spots. Compacted snow across the whole road in other spots. No problems. But, there is an advantage to having all those other cars pack the snow down for you before you travel on it.

Also, did not stop at the slick spots, but some distance away from them, so I could get a running start through. Some people who drive the leter of the law might have a problem with running stop signs, but the spirit of law certainly supports that action in these road conditions.

Think the Hydroedges and BT Tech plate saved me once, doing a lane change at 50 mph and hitting a between-lane slush mound. Aimed for a what appeared to be a low spot, but when I hit the whole bottom of the car had slush pounding off it. Car tracked straight. Damn beemer doing 30 mph in the middle of the road! Would not have wanted to do that if it would have been keeping up with traffic.

4X4 drivers still do not know how to drive in snow. Too damn overconfident for the real world. Saw a few of the aero-dynamic styled dodges spun out in the middle of the interstate, luckily going the other way than I was. Otherwise it would have been a 2 1/2 hour drive home, rather than 1 1/2 hour.

I guess my conclusion is the Prius is OK for the metropolitan bad weather commute. Based on the stories on PC here, I doubt I would do a winter snow storm cross country trip with it . That is what Trains are for.



Jayman,

Do you know if the vehicle dynamics is controlled by its own computer, or is that part of the Hybrid ECU ? I know you said you had the Hybrid ECU reflashed. But if there is a different computer for the traction control / abs / vsc maybe that needs new firmware ?

 

<div class='quotetop'>QUOTE(donee @ Feb 13 2007, 01:46 PM) [snapback]389538[/snapback]</div>

That is very similar to the Variable Frequency Drive technology used in industrial process control, where limited amount of Cascade control can be used on something like a conveyer system. In practise it's difficult to achieve, as frequency/voltage spiking can create "corona" and break down the motor insulation.

Considering how long the MG has to last in the Prius, at least the expected lifetime, I would have to suggest the engineers wanted to avoid corona damage at all costs

<div class='quotetop'>QUOTE(donee @ Feb 13 2007, 08:21 PM) [snapback]389845[/snapback]</div>

I have never received a firm answer to that question, so I really don't know

 

The snow finally hit the northeast, and I went out for the first real
go at spinning around and testing conditions in quite a while.
Executive summary: '04 prius, NO reflashes since I got it, and no
problems even when basically stuck in deep stuff. Details here.
.
_H*

 

<div class='quotetop'>QUOTE(hobbit @ Feb 14 2007, 07:13 PM) [snapback]390521[/snapback]</div>

Ok that does it. I'm going to have to hunt down a Prius owner in Winnipeg and drive their car. Then have them drive my car. Something just doesn't add up here.

Note: the only problem I had this winter was in 2 ft of churned up drifted snow. Otherwise with the studded tires, no problems.