Mountain driving

now i dont own a Prius, but i do have my experiances in my friends prius

when we took a road trip in mammoth his prius made the 9,000 ft journey up to mammoth maountain. now this wasnt just an ordnary drive, we were lucky and we hit a large snow storm. no probd in the prius despite the ice and snow. 9.5-10

 

Consumer Union conducted a test where a Prius was driven slowly to discharge the battery, pink, and then driven up a steep incline. The car died in a short time. With a fully charged battery the car made it up the mountain going 55MPH with no problems. The test was conducted last year but, I couldn't find the article. Lesson learned: go up the mountain with a green battery and go the speed that keeps the battery in the blue. If you get in a bind, there is a solution--pull off the side of the road, put it in park and let the engine charge the battery.

 

???? the motor can only go 42???? maybe im confused???? :roll:

 

jtm, I remember reading a similar article, but about either the Civic Hybrid or Insight (Couldn't locate article on CR website, can't even remember for certain if they wrote it).

Regardless, even if you do completely exhaust your battery (difficult to do as reported here), your speed would just be reduced and the battery recharged as soon as conditions allowed. There is no need to stop the car or put it in park, just drive it! (Even with a completely discharged battery, the system can still get torque if needed from the motor by generating elec directly off the engine - a big advantage IMA systems can't provide!)

Indeed, to get the conditions you described is very difficult on the Prius, as you discharge the battery more and more, the system uses the battery less and less. Stealth mode is gradually reduced and two bars is about the lowest you can go without sustained full throttle acceleration (before you hit the mountain, at least)

Most climbs don't keep the grade constant the entire time, the system gets a chance to charge up on these flatter portions.

 

On long, steep climbs even a "green" battery will deplete in just a few minutes if you're going fast (60+mph). A subtle side effect is that as the electric assist fades, the gasoline engine has to rev up more to make up the missing power.
When that happens, the CV transmission really gets noisy because when the electric motor side of the planetary gear system slows down, the other side has to speed up. When both sides are at equal RMP's, the drive noise is much less. I think that's where the speed limit on gas only, enters the equation.
A turbo would really solve the problem.

 

I am on vacation right now. One of the objectives was to go up Pikes peak, over 14,000 ft. I had no problems at all. Down to one purple bar on the way up. All green bars on the way down. ICE only came on twice, while climbing slight uphill. Approx 35 mpg up and down.

Ron

 

If ICE means Internal Combustion Engine, then it's iimpossible that it only came on twice on the way UP to Pikes Peak. It might have gone OFF twice but almost all the power would have to come from the ICE and it would be on all the time you were going uphill. It could well have been OFF on the way down.

 

From the game GT4, the Prius can maintain a speed of ~75mph with a drained battery on mostly flat level ground.

That's pretty good because that's above most usa speed limits.

Also, this means the car can never die on the road. I don't think these 'tests' of the Prius dying and not being able to move with a drained battery even on inclines are valid unless it's some high torque test at low speeds of which the ICE is not designed to be very useful nor powerful.

The Prius without battery assist drives like a Geo Metro probably, but there's still 67hp usable there.

 

Sure - I did have the luxury of downhills to give the battery a little tickle up, so that is probably why I got such good performance.

I guess your US roads are probably better than those I was driving on, as it would have been sheer suicide to travel anywhere near 100km/h (60mph) - LOL

 

<div class='quotetop'>QUOTE(energy1\";p=\"90427)</div>

Correct me if I am wrong Ron, but I believe he meant the ICE only came on twice on the way down, due to slight uphill at some points.

 

I must be missing something - what is it about climbing a hill that causes the Prius to deplete the battery?

 

<div class='quotetop'>QUOTE(jfh3\";p=\"90529)</div>

Nothing usually, but the system will kick in the motor to assist the engine if more power is needed than the engine can supply alone. To drain the battery you need some combination of long, high, and fast speed.

Most people won't ever acheive this without purposely trying, even going fast up mountains. There are a few conditions (Steve above) where you run out of assist and system speed & power goes down until it can recover. Most report no problems even in fast mountiain conditions, YMMV.

 

<div class='quotetop'>QUOTE(priusdave\";p=\"90264)</div>

I believe you are
The ELECTRIC motor will only go SOLO to 42 MPH. Except I've seen arrows only from the battery through the electric motor on interstate downhills at higher speeds. The ICE is probably turning over but not providing any push.

If you are driving along on a relatively flat road under 42 MPH and battery and engine temps are appropriate, the car will cut the gas engine until the computer senses a need for more power. If you go over 42, the ICE will kick in. Any time from 0 to however fast you can go, the car will use the ICE and/or electric motor as it sees fit.

The car theoretically will go 104 (or is it 106) MPH.

 

Thought I would throw in my two cents.
I LIVE in the mtns, just below the snow line outside of Fresno, CA, and my 2005 does GREAT! I had my doubts when I was driving my lil girl home that first night, but she did wonderfully. I am used to SUV's and trucks, and not a big fan of 4 cyl's- but the Prius has truely proven itself. I travel A LOT- going to southern CA, and Las Vegas, San Fran- and I have not been unhappy so far- 8,500 miles in 3 months!
Hope this helps

 

I believe it would take an extremely long and very slow climb to stall the Prius. I remember about 20 years ago travelling to the Smokie Mountains from the south on a two lane road behind a big RV with a trailer going up an incline of about 2 miles going 10 MPH. The incline ends in an area called Maggie Valley NC. I was driving a 4 cylinder Volvo pulling a pop top camper in first gear. I don't believe the Prius could make that pull at 10 MPH. The slow speed is the problem since the engine sees high gear all the time. That road is probably 4 lanes now and the situation eliminated. Every half mile or so there were small parking areas for trucks that were overheating. Just guessing, but going 25 MPH and above, the Prius would have no problem with that mountain. I would classify this lack of low speed torque of the engine by itself as a shortcoming but, nothing that needs addressing by Toyota.

 

While the engine has little low speed torque, and the car only has one gear ratio, the motor has LOTS of low speed torque. The battery can be completely "drained" and the system can still use the motor for torque by spinning the generator. In fact, at a low speed and a "drained" battery, it would probably spin the engine higher and start charging the battery as well.

 

<div class='quotetop'>QUOTE(gschoen\";p=\"90634)</div>

Yup, it would act mostly as a series hybrid, the same way train diesel locomotives and ships operate: ICE->generator->motor, though because of the PSD, some of the ICE power would 'leak' directly to the wheels.

 

I recently took our 4-month-old 2005 Prius, with two other adult passengers, on a 1000-mile trip from San Francisco into Sequoia, King's Canyon, and Yosemite National Parks. It was a pleasure to drive and performed beautifully on all the mountain roads except one: When I headed up Tioga Pass from Lee Vining, it started out fine but, long before the top, slowed to a maximum speed of 30-35 mph. (Ouch!) The engine was also very noisy, and I started wondering whether we were going to make it or not. I'm not sure how fast I started up the grade, but it was probably around 55mph. Could the problem be that I depleted the battery too quickly by going up a steep, long grade too fast? (I don't normally keep the screen with the battery charge visible.) Going up the same pass in the opposite direction, which is much less steep, was no problem.

 

For those of you who are from CA, have any of you gone through the steep hill going from Camarillo back to LA (101 S)? My girlfriend and I love going to Santa Barbara but I'm affraid the Prius will struggle with the hill. (We're from Los Angeles). I've gone on many occasions in my old Mustang (5.0) and more recently on my Firebird (which I sold). The mustang allways struggled to keep the speed nearing the top of the hill (speeds drop from 70 to ~55 mph). And in the Firebird (which has ~300 hp and 330 lb-ft of torque) I'd have to downshift from 6th to 5th in order to keep my speed up to 75+ mph. Has anyone driven their Prius up that hill? I want to go, but I don't want to have to get on my hybrid too hard. I like to baby it.

Cheers,
LT1bird