Is it Prudent to Neutral at 60 mph Down a Hill ?

I seems like you're loosing out on the benefits of regenerative braking doesn't it? The only times I ever shifted to "N" was to avoid my hybrid battery filling to the top, keeping the car from doing a negative recalibration of the hybrid battery (this was on my first Prius)

 

I do not understand why do you want to be in "N" while coasting............

 

Yes. The hardware limit seems to have jumped from 42 to 62 MPH where the engine MUST run to protect M/G1. Toyota added a second planetary gear raise this threshold.

It is very unlikely you will get better MPG in N than in D, as all braking is then friction braking, with no regen.

While the engine is revolving, it is safe to be in N at any speed. Not productive, but safe. The unsafe bit is putting it in N at a low speed with the engine stopped, then coasting to a high (over 62 MPH) speed. In N the engine can neither start nor stop, so M/G1 is at risk.

0 to 62 engine may or may not revolve in N, cannot start or stop revolving.
62 to 115 engine must revolve, even in N. If it does not, damage may occur to M/G1.

 

Toyota is required by law to have an N. You are never required to use it. The only time I ever recommend N is about once a month, if needed, stop in N to clear rust off the rotors.

Ohio does not appear to prohibit coasting downhill, as many states do.

 

I feather the gas pedal when coasting to avoid charging.

When you're in Neutral IIRC there's no charging. I just leave it in D 95% of time. Use B (sparingly) on extreme downhill runs, just to forestall fully charged battery.

Rolling downhill at 75 mph sounds dangerous. And possibly damaging, though I don't really know. The only time I use Neutral is when rolling a wheel into contact with curb when parking.

Yeah, from page 175 of the 2010 Owner's Manual:

 

I guess now I know why dot.gov is so interested in self-driving cars......

Roadshow: Downhill in neutral is illegal and dumb, and a lot of drivers do it – The Mercury News

Why is it illegal to coast in neutral? | Yahoo Answers

 

You can achieve zero regen and zero energy use by careful use of the right position of what you U.S. folk call the "gas pedal". The energy monitor will show you when this happening. Far safer for you and the car than using neutral IMHO!

Posted via the PriusChat mobile app.

 

If you are above 46 MPH and in D, the engine is already spinning. You can safely shift to N without putting MG1 at risk. Legality and personal safety are another matter.

If you are moving below 46 MPH, the engine may or may not be spinning, depending on conditions. The mechanical danger happens if the engine is not spinning, and you shift to N, and you then roll up to a too high speed (e.g. greater than 62, though other sources are more conservative and suggest lower limits).

When the car is moving, MG1 must spin faster when the engine is not spinning.

 

You could just press the accelerator enough to negate regen braking...with is effectively the same as being in N but without losing the ability to have power on demand.

 

Neutral does a lot more than turn off the regen. It essentially turns off the Synergy drive. This is probably not a good thing. There has been a lot of discussion about this on PC. Do a search.

 

See https://priuschat.com/index.php?posts/2446751

Posted via the PriusChat mobile app.

 

No

 

Its the same topic dude...

 

The N position in a Prius emulates a Neutral to the driver, but does not resemble the Neutral in any other car. No gears or clutches disengage. The electric motors are just disconnected electrically. There are no MPG advantages using N and frequently it will get worse MPG by a minuscule amount. (The engine will be idling instead of being an air pump, and there is no regeneration if the motors are not electrically connected)

That said, if the EV light is out, it is safe and if the EV light is on it is still safe so long as you do not gain speed.

While it is illegal in any state with mountains, it seems to be legal in Ohio.

What car did you get? The Prius is computer controlled, you only give an opinion.

 

Gen2 anyways better to go into B mode for engine braking after the battery is full. What's happening when the batt is full is the real brake pads are getting used for stopping, vs regen braking...I assume that's in N too. Going into N is not recommended in most cases.

 

Going down long hills, or twisty mountain roads in my Prius scares the crap out of me.

There seems like there's no way to slow the car down, other than riding the brake pedal the whole way. The B mode doesn't seem to do anything to slow the car. It was nice in my Camry, when I could down shift into third or second gear, and the car would stay at a fairly steady downhill speed and I didn't have to use the brakes as often.

There is no bloody way, I would drive my Prius down mountain roads that are snowy or icy. The car just feels too unpredictable.