Reversing

The Prius will use the gasoline engine if necessary to produce electricity to move the car backwards. The engine cannot really provide torque in the opposite direction (backwards - the engine is designed to rotate forwards, which is the direction it is used 99.9% of the time) and the PSD will use this torque to have the generator generate electricity for the battery and for the electric motor to move around in reverse.
The electric motor has plenty torque and HPs to move a car in reverse in all conditions of use. I never had an issue with not enough power to reverse in snow.
I don't know what is the max speed in reverse, that would be interesting to know.

 

Gen 2 was 22 MPH, but Gen 3 added another planetary gear so that may no longer be true.

 

Doubtful 60 kW or 80 HP and instant torque wouldn't be enough to reverse out of the toughest situations.

 

Well, in reverse any HSD equipped car uses MG2 to back up (reverse) - so yes, electric only. You can get into a situation where that electric motor struggles to get the car moving, but it's pretty rare. I encountered a -very- steep hill on the Sunshine Coast in Gibsons, where Pearl (a GII Prius), could barely get moving backing up the hill. This was on a sidestreet. It did move, just not very fast, and with almost full throttle.
I wouldn't think snow would provide enough drag, as the tyre traction should limit motion before motor torque does.
Oh, and no, you can't really put chains on a Prius to increase traction, as there isn't really enough room, and you are told not to in the owners manual. Though cable chains are, I think, ok.

 

Chains rules for link chains are shown in both the Gen 3 and Gen 4 Prius manuals.

The gen 3 manual also says no radial cable chains or V bar type for 15" wheels. I'm not sure why. I think that circumferential cables are OK but the radial sections that cross the tire must be chain links.

 

An automotive magazine in Brazil is doing a long-term test with the Prius Gen 4. And today a note came out that during a trip the car did not have "strength" to climb a reverse garage, because it only uses the electric motor for it. I found it curious because I had never heard of this problem in this Prius generation.



Reporter Rodrigo Ribeiro and assistant editor Leonardo Felix took advantage of a long weekend to go from São Paulo to Angra dos Reis (RJ).

And they went with the Prius. On the first leg, the pair were only compliments.
"We took a lot of rain, even with some long stretches with thick slides of water. Even so, we do not get any fright for loss of grip. It remained under complete control all the time, "comments Léo.

After staying in a house built on a level well below the street with a steep ramp that led to the garage, the reporters were startled when they tried to get back to the Prius. "After climbing a few meters, he stopped and came down a bit at the end of the maneuver," says Rodrigo. The surprise: the reverse gear is propelled only by the electric motor and, on such a steep slope, the car did not have the strength to climb.

In addition, with the effort the entire battery charge was quickly eliminated. Carefully, the reporter went down again to the base, waited for the combustion engine to apply a little charge on the batteries and repeated the attempt. And again the Prius took refuge.

"Again, he climbed a few meters, stopped and began to descend," he said. Since the reverse operates exclusively with the electric motor - provided, of course, there is a charge on the battery - the output has been to maneuver the car and, up front, to climb the slope driven by the combustion engine. Luckily, the space allowed to reverse the direction of the car.

 

i have read this in the past. maybe you need to force charge the battery first. not sure if you can or not on gen 4

 

I'm guessing the force charging works the same for the Gen 4. Why wouldn't it?

 

you're probably right, i just wasn't sure

 

How is that done?

 

put the parking brake on, put your foot on the brake, and floor it until the bars fill up

 

Must be a very steep hill - when I first got my Prius I tested its reverse capability as I knew the way it worked and it didn't to have any significant problem.

Although it is only MG2 that can drive the car in reverse I'm surprised that the Gen4 doesn't use the engine to provide electrical power when the battery is depleted. The engine could drive MG1 to provide power to MG2. During this time the ICE would be trying to propel the car forwards while MG2 is propelling backwards so it would lessen the thrust some what.

kevin

 

Maybe it does not have to be a very steep hill.
Apparently, if the car has luggage and four passengers, it may not be able to climb.
Although it is an atypical situation, it seems to me a mistake of Toyota.

 

that's when 3 people get out and push

 

Here's Rodrigo and Leonardo taking a break with the film crew on the beach

Loveislandskeggy by kithmo posted Jun 19, 2019 at 9:34 PM

 

That is the complication, exactly. Whatever torque the engine is producing, 72 percent of it is tending to push the car forward, so there are limits on what can be accomplished in reverse.