ICE Runs in reverse..

Yes, the engine running while in reverse is somewhat counter-productive. In fact, you can see that process in action at the bottom of this webpage.

Look at those animations closely. Though a little on choppy side, they do get the point across. The PSD is a very interesting device.

 

Amazing, indeed! The ICE runs (forward, of course), turning MG1, which generates electricity, which goes to MG2, which propels the car (backwards, in this case). I believe the geometry of the PSD limits how fast you can back up.

60% of the torque of the engine goes to MG2 and the wheels (forward) but force does work only in proportion to distance traveled, so that at slow speeds, where MG1 is turning very fast and MG2 is turning slowly, most of the power from the ICE goes through MG1 rather than directly to the wheels and MG2, so I believe there is little energy lost when going backwards at slow speeds. The counter-productive work done by the ICE on MG2 is small, while the work that follows the electrical path from MG1 to MG2 is large.

 

<div class='quotetop'>QUOTE(daniel @ Jun 20 2007, 12:06 PM) [snapback]465247[/snapback]</div>

This is correct. The HSD is a work of wonder. As an engineer, as soon as I understood how the HSD worked, I knew I had to have a Prius.

As for backing up, most cars are geared down in reverse. Most people don't need to drive fast in reverse, and car companies (and insurers) would just as soon you didn't.

Tom

 

<div class='quotetop'>QUOTE(qbee42 @ Jun 20 2007, 12:51 PM) [snapback]465323[/snapback]</div>

One cool little thing about the Prius is that the digital speedometer works in reverse (this is the first car I've owned without analogue gauges; those didn't)...I've seen it display 16mph, backing down my driveway in the morning, late to the transit station (but I always stop to look before pulling into the street!)

I'm fascinated by this for some strange reason.

 

<div class='quotetop'>QUOTE(Pinto Girl @ Jun 20 2007, 11:06 AM) [snapback]465332[/snapback]</div>

What's your best 0-16 time, or is it 0 to minus 16? B)

 

You don't understand how PSD works until you "get" why the ICE can spin forward yet the Prius moves backward.

Planetary gear-set is amusing. I bought some to play/show around from a hobby store.

 

<div class='quotetop'>QUOTE(Pinto Girl @ Jun 20 2007, 02:06 PM) [snapback]465332[/snapback]</div>

If I was backing up at 16MPH I sure would not be looking at the speedometer!!!!!!

 

<div class='quotetop'>QUOTE(Tom 6850 @ Jun 20 2007, 02:54 PM) [snapback]465380[/snapback]</div>

You know, I didn't have my head turned to look behind me (I normally back up using the mirrors and maybe the rear view camera)...and --darn--- the yard was sure going by fast that day (I had the pedal to the floor for a little bit); I simply *had* to see exactly *how* fast...

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I'm not sure if this has anything to do with what we're discussing or not, but I've always wanted to take the body off of a car and put it on facing the opposite direction, so you'd drive down the road looking through the rear window.

I guess you'd still be using the forward gears, though, normally...

Hmmmmmm....

This brings up the philosophical question: does a car with its body on backwards drive backwards...or not...?? I mean the chassis thinks it's still going forward, but the body doesn't.

Wondering, now, if I'm not overthinking this just a bit.

 

is there a page somewhere where i can learn all these abbreviations.

it took me a couple of posts when i first got here to figure out what ICE was.

now, there's PSD and MG (magnetic generator?)


it just makes it difficult for us newbies to follow any of this stuff.

thanks in advance.

 

<div class='quotetop'>QUOTE(PriusMatt @ Jun 20 2007, 04:37 PM) [snapback]465399[/snapback]</div>

The great Graham Davies site:
http://www.ecrostech.com/prius/original/Un...ng/Contents.htm

 

<div class='quotetop'>QUOTE(Pinto Girl @ Jun 20 2007, 11:06 AM) [snapback]465332[/snapback]</div>

This makes me wonder: When you go backwards in a Prius, does the odometer go forward or backwards?

<div class='quotetop'>QUOTE(PriusMatt @ Jun 20 2007, 01:37 PM) [snapback]465399[/snapback]</div>

PSD = Power-Split Device. It's essentially a differential, and it serves the purpose of a transmission in a conventional car. It connects the engine (ICE), MG1, and MG2. MG2 is connected to the wheels through a constant reduction gear.

MG = Motor-Generator. The Prius has two. Both can operate as either motors or as generators, in either direction, on the whim of the computer.

 

thanks for replies. cool technology. my car is smarter than i am!!!

also, just found the list of abbreviations under the "features" section.

 

<div class='quotetop'>QUOTE(PriusMatt @ Jun 20 2007, 09:06 PM) [snapback]465579[/snapback]</div>

Next idea for a bumpersticker: "My car is smarter than your honor student"

 

<div class='quotetop'>QUOTE(daniel @ Jun 20 2007, 08:15 PM) [snapback]465563[/snapback]</div>

I'll have to test that out one of these days! I'm sure the odometer won't go backwards unless the Toyota engineers saw Ferris Bueller's Day Off and realized the benefit

 

<div class='quotetop'>QUOTE(Presto @ Jun 21 2007, 09:32 AM) [snapback]465788[/snapback]</div>

I have tested this on other cars with electronic speedos and the odo goes forward while traveling in reverse even at maximum warp. :mellow: