San Francisco to take delivery of three plug-in Priuses
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Later today, San Francisco Mayor Gavin Newsom is expected to take delivery of three newly-converted plug-in Toyota Priuses. The cars will be used by the city and county for official business. The conversions were done by the crew at Pat's Garage in San Francisco using a kit from Hymotion. Hymotion was bought last year by lithium ion cell supplier A123 Systems. Hymotion claims their system can provide 30 miles of electric range for a Prius although the car's powertrain hasn't been modified. Getting that much range without the engine starting will require an extremely light foot on the throttle. Sometime this year, Hymotion plans to start offering their conversion kit to consumers.
[Sources: GreenCarCongress, GreenGears]
Reader Comments (Page 1 of 1)
mike k. 10:04AM (2/21/2008)
About the comment to have a light foot on the throttle.
Wouldn't these conversion kits also equip the car with the EV mode button? That would make sense wouldn't it.
Also, does anybody know if any of these conversions reprogram the prius computer to be aware of the fact that its a plugin and possibly do less turning on and off of the engine or something?
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Sam Abuelsamid 10:17AM (2/21/2008)
The problem you run into with conversion hybrids was outlined in the interview I did with Pete Savagian from GM recently. Current hybrids have motors sized only for low speed, low acceleration and power boost activity. The electric motor simply doesn't have enough power to propel the vehicle on it's own most of the time, the way most people drive. Yes the battery has enough capacity to go further, but when the driver demand exceeds the capability of the motor, the engine will start regardless. The Toyota Highlander and Lexus LS600 have an EV button, but anything above minimal acceleration will deactivate it. http://www.autobloggreen.com/2008/02/13/autobloggreen-qanda-peter-savagian-talks-about-studying-driver-be/
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Tim 10:41AM (2/21/2008)
Hey Sam
How about cruising on the freeway. Doesn't the prius's gas engine turn off when you are cruising at say 70?
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Sam Abuelsamid 10:51AM (2/21/2008)
I'm not sure about the Prius but other Toyota hybrids I've tried lately do not shut off the engine at highway speeds unless you are coasting or braking. At steady state they only seem to run on batteries up to about 35mph.
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bluedaze08 2:56PM (2/21/2008)
Well, I am wondering about the Toyota' Priuses Plug-Ins that were brought to US (Berkeley and Irvine Univ.).. From Popular Mechanics, they were saying that these Plug-in's modifications only concerned putting bigger batteries, and no other detail was given about a bigger electric motor in them.. And these plug-ins are able to run in electric mode only up to 50mph for 8 miles. Anyways, I was wondering, anyone has any comments on this?
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Chris M 8:09PM (2/21/2008)
Bluedaze, I think you have confused the aftermarket conversions of existing models with the prototype plug-ins being developed and tested by Toyota.
The aftermarket conversions don't change the electric motor or the power split planetary gear, and are limited in EV mode operation. The IC engine must spin at speeds above 45 mph to prevent overrevving one of the motor/generators, but it can sometimes spin the engine without burning gas. Fast acceleration requires power from both IC engine and electric motors.
The Toyota plug-in Prius prototype uses a larger battery, a more powerful electric motor, and a different planetary gear ratio on the power split device. Due to all those changes, it can go up to 60 mph without spinning the IC engine, and is less likely to need the IC engine for fast acceleration.
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