42 MPH Question

mostl harmless · 07-01-2005, 04:03 PM

Just wondering... I notice that my 2004 Prius spins the ICE at about 42 MPH. From reading Graham's description of the original THS this makes sense to preserve MG1. I thought that THS II allowed higher revs for MG1 than THS.

Did they change the gear ratios in the PSD, the gearing of the ring gear to the wheels, or is this just an artifact of the THS software?

mostly curious,
jim

DanMan32 · 07-01-2005, 04:23 PM

They did design MG1 to allow more revs, but I believe the intent was to get more generated power. I believe what you're seeing is an artifact. Shouldn't matter much though.

hobbit · 07-02-2005, 11:17 AM

If you get in a situation where you're under 42
mph, ICE-off, on a downhill, you can move to Neutral
and actually wind up going considerably faster than
42 mph without the engine spinning at all.
Kind of fun, and probably helps mileage a bit. Until you
have to slow down, of course; moving back to D
spins the engine and enables regen.
_
Save the rants about "illegal to coast in neutral".
The definition doesn't apply to the prius, because the
geartrain is always engaged and Neutral is just an
electrical state. The car can coast like a soapbox
derby racer anyways, and that's part of the fun.
_
_H*

07-01-2005, 04:03 PM	#1
mostl harmless Join Date: May 2005 Location: Sykesville, MD Posts: 11 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	42 MPH Question Just wondering... I notice that my 2004 Prius spins the ICE at about 42 MPH. From reading Graham's description of the original THS this makes sense to preserve MG1. I thought that THS II allowed higher revs for MG1 than THS. Did they change the gear ratios in the PSD, the gearing of the ring gear to the wheels, or is this just an artifact of the THS software? mostly curious, jim

07-02-2005, 11:17 AM	#3
hobbit Senior Member Join Date: Mar 2005 Location: Bahstahn Posts: 3,630 My Car: Model: Package: Thanks: 0 Thanked 216 Times in 118 Posts Friends: 0	Re: 42 MPH Question If you get in a situation where you're under 42 mph, ICE-off, on a downhill, you can move to Neutral and actually wind up going considerably faster than 42 mph without the engine spinning at all. Kind of fun, and probably helps mileage a bit. Until you have to slow down, of course; moving back to D spins the engine and enables regen. _ Save the rants about "illegal to coast in neutral". The definition doesn't apply to the prius, because the geartrain is always engaged and Neutral is just an electrical state. The car can coast like a soapbox derby racer anyways, and that's part of the fun. _ _H*

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07-01-2005, 04:23 PM	#2
DanMan32 Join Date: Aug 2004 Location: Tampa Bay, FL Posts: 3,775 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	They did design MG1 to allow more revs, but I believe the intent was to get more generated power. I believe what you're seeing is an artifact. Shouldn't matter much though.