Emergency Shift lock override

<div class='quotetop'>QUOTE(ilusnforc @ Feb 14 2007, 09:42 AM) [snapback]390241[/snapback]</div>

You've posted this before and you are just plain wrong. The HSD is not like you describe.

 

<div class='quotetop'>QUOTE(Bill Merchant @ Feb 17 2007, 01:23 AM) [snapback]391936[/snapback]</div>

I don't recall ever posting anything about the HSD or it's operation, I tried searching through all of my previous posts and couldn't find anything related...?
Perhaps you can elaborate on how the HSD does work rather than simply telling me I'm "just plain wrong"? I may not properly understand how it works, but how will I ever know if you can't explain?

Your comment was "just plain rude" and uncalled for.

 

<div class='quotetop'>QUOTE(ilusnforc @ Feb 17 2007, 01:38 AM) [snapback]391962[/snapback]</div>

I'm sorry, I didn't mean to be rude. I may have read this before and just thought you had posted the misinformation before. The Hybrid Synergy Drive is a lot more than only one physical gear.

I would direct you to Graham Davie's discussion of The Prius "Continuously Variable Transmission". Please click HERE, then on Understanding the Prius, then on Continuously Variable Transmission. For some actual photos of the gears, look at the PrivateNRG page. John1701a has some excellent PSD animations.

 

<div class='quotetop'>QUOTE(ilusnforc @ Feb 14 2007, 12:42 PM) [snapback]390241[/snapback]</div>

this is correct. the 2g prius is shift by wire, all the other yota/lexus hybrids are mechanically linked.

this is not the reason for the difference. as others have stated, other hybrids also have CVTs. however, the others have a shift cable and thus, shift lock overrides.

 

<div class='quotetop'>QUOTE(hill @ Feb 16 2007, 03:21 PM) [snapback]391633[/snapback]</div>

I have no doubt that is true. All I can report is the experience of my co-worker with his 2006 Range Rover HSE. He's had it almost 11 months no, with no issues. Currently has around 10,000 km on it. It could very well be that he has the only Rover that was actually put together correctly.

About the only thing that has happened so far was damage to the driver side adaptive HID headlight, when we managed to pop a deer at night. That happened a couple of months ago, can't really fault the RR for that. Most deer are suicidal by nature.

Of course, I've had issues with my Prius, like the "stall" and the dead gas gauge. With a vehicle you can go with the median, but you never know which cohort you end up with once you buy the thing.

 

<div class='quotetop'>QUOTE(galaxee @ Feb 18 2007, 09:49 AM) [snapback]392355[/snapback]</div>

Yes, that's what I was getting at...

<div class='quotetop'>QUOTE(Bill Merchant @ Feb 18 2007, 01:25 AM) [snapback]392278[/snapback]</div>

That was taken more literally than it was meant. Yes, I'm quite familiar with how the Prius CVT operates and I do understand that it's a planetary system comprised of several "gears".

One definition of the word "gear" is:
-a part, as a disk, wheel, or section of a shaft, having cut teeth of such form, size, and spacing that they mesh with teeth in another part to transmit or receive force and motion.

What I meant was a different meaning of the same word:
-one of several possible arrangements of such parts in a mechanism, as an automobile transmission, for affording different relations of torque and speed between the driving and the driven machinery, or for permitting the driven machinery to run in either direction: first gear; reverse gear.

That actually defines the CVT of the Prius quite well in the singular form as the Prius CVT has several possible arrangements (variable) with only one gear (no shifting). The plural word "gears" using the same meaning for most other cars would be something like "five possible arrangements of such parts in a mechanism..." Therefore, I mentioned the Prius having only one gear because that is a definition of the word "gear". My original post in this thread was in relation to it's topic, the shift lock, not the operation of a CVT broken down into individual components. Most cars simply allow the "gear shifter" to move the cable or linkages in order to put the transmission into neutral overriding the park locks. Calling it "misinformation" would be misinforming, a better choice of word may be "misunderstood". Sorry for the confusion, hope that cleared things up.

 

<div class='quotetop'>QUOTE(Dick K @ Feb 19 2007, 01:26 AM) [snapback]392697[/snapback]</div>

I thought your towing problem -- resulting in the wheels being locked in park -- stemmed from a loose plug behind the dash so the car wouldn't power up and you therefore could not put the car in neutral. I don't imagine this would be an issue with the car in a ditch unless it had sustained heavy damage getting into said ditch.

 

"Also many diesel powered motor homes have it, The mfgs have had the forethought to have a way to put it in neutral in an emergency"

Actually, the heavy duty Allison 6 speed transmissions used in diesel pusher coaches and motorhomes lack a parking pawl. The pushbutton dash gear selector is R-N-D, with up and down arrow buttons to manually select a gear while in motion.

Usually, upon a serious electronic fault, the Allison is designed to go into neutral. As long as there is enough air pressure to release the parking brakes, the coach can be flat towed a very short distance at low speeds.

 

<div class='quotetop'>QUOTE(Bill Merchant @ Feb 14 2007, 02:07 AM) [snapback]390060[/snapback]</div>

I think it is very valid concern. How many times have you seen a disabled car blocking traffic on a roadway and said to yourself (or maybe even yelled out), "Push your broken POS to the side of the road!" How many other cars are imobilized by an electrical failure? None that I can think of.

Sounds like a nice security feature, but I think it could be equally hazardous. Toyota should have provided a way manually release the car from PARK, even if was some kind of lever or something under the dash - or even under the hood.

There are a $#!+load of Priuses on the road today. While they are highly reliable cars, they will be more prone to breakdowns as they start aging. We dould be driving the only cars that can't be pushed off the road due to something as simple as a dead 12V battery. Imagine the road rage you may be subject to.

 

<div class='quotetop'>QUOTE(Curtis SAC @ Mar 2 2007, 02:56 PM) [snapback]399221[/snapback]</div>

I think it would be highly unlikely that the 12V system would just drop dead as you're driving down the road because I'm quite sure the DC/DC converter trickles power to the 12V system from the HV battery which is in turn charged by regenerative braking (there is no alternator). And, if the 12V battery was completely dead and the DC/DC converter fails and the Prius dies in the middle of the road losing all electrical power, I don't think it would be possible to engage Park. I think the issue at stake here is that once the 12V battery dies (in most cases when the car sits for long periods of time or the Prius fails to "boot") the Prius is not able to be moved without dragging the front wheels. If the only problem is that the 12V battery died then maybe the tow truck driver can hook up jumper cables to the proper locations under the hood indicated in the owners manual, then place the car in "Neutral" and be able to move it. I don't have the time to re-read this entire thread again so I'm not sure of any other issues that this workaround couldn't fix, like computers dying or electrical problems etc...

 

<div class='quotetop'>QUOTE(Bill Merchant @ Feb 18 2007, 02:25 AM) [snapback]392278[/snapback]</div>

I have always found it easiest to desscribe the Prius CVT as a differnetial. Similar to what you see in the back of a rear-wheel drive car but the power being combined instead of being split. The "eCVT" is like having MG1 on one axle, the ICE on the other, and the output to the wheels (via MG2) through the drive shaft.

 

I'm coming into this thread way late, but I can probably help
straighten a lot of this out. First of all
_ http://techno-fandom.org/~hobbit/pix/udh1/351park.jpg and
_ http://techno-fandom.org/~hobbit/pix/udh1/352park.jpg
show the 3-phase actuator for the parking pawl in the '04+. [The
Classic has a mechanical parking linkage from the lever with, as
has been noted, an override under a little pry-out cover under
the steering column.] The problem with the 60:1 reduction ratio
and the fact that you need to bang those coils fast enough to
create a proper rotating magnetic field to turn the rotor is,
you aren't going to do it by just jumping a few wires even if you
find the right spots in the transmission ECU plug. [Which, I might
add, is conveniently right in the passenger footwell.] What needs
to happen is that someone builds a widget that provides 12V and a
3-phase switching output that adapts right into the transmission
ECU plug, and allows direct actuation of the parking-pawl widget.
.
Alternatively, you *can* get under the car and unbolt the thing,
but it's pretty tight up in back of the transaxle. They didn't
want to make it easy, after all.
.
If a shop wants to leave a car in neutral but powered down, the
easy trick is to get to neutral and pull the PCON fuse or relay.
The car bitches and moans about this, but you *can* get it powered
off and then be able to push it around without 12V. But of course
that's not going to conveniently happen out on the road in the
event of a random 12V failure.
.
_H*