Hi Prasad, The Prius does not have a switch for an "electric only" mode. The ECU determines when to turn on the gas engine. There have been extensive discussions of this on the Yahoo PriusMods and Prius_Technical_Stuff mail lists.
The simple answer is that the Prius actually has two electric motors. One functions as a generator and the other functions as a traction motor. Due to the configuration of the motors, the Prius cannot go over 42MPH without over-spinning the traction motor - But the ICE engine can be engaged to prevent this over-spinning. The upshot of this is that without an additional motor, the Prius would be limited to 42MPH. the traction motor is also not rated for continuous use. There are better explanations all this in the Yahoo news groups I mentioned. As far as Toyota being responsive: Considering the complexity of the task, I doubt that very much. As an example, when the Prius first came out, it didn't have cruise control and Toyota insisted that it was not possible to retrofit it. There was a great demand for cruise control, but Toyota was initially silent. After great cost and some perusing of the service manuals, I was able to install a factory cruise control on my Prius. Eventually Toyota came out with a cruise control kit. My point is that a simple thing such as cruise control, which the car was designed for, and for which parts already existed, took Toyota an enormous amount of time to acknowledge was even possible. I have looked several times into converting a Prius into pure electric, but have been extremely discouraged. The various Prius components, such as the regen., braking, AC/heating are all integrated closely. Since Toyota does not provide the software for the ECUs, it would be very tedious to replace them. Also the differential and the two electric motors are integrated into a water cooled housing. So if you decide to keep them, then you will also need to keep the entire cooling system. I think the oil pump is also integrated into this. Then there is the issue of the battery placement as John Wayland has pointed out. Placing batteries in the Prius is not much easier than any other ICE car. Maybe a pack of Saft LiIon batteries could be tucked away nicely. Alex Karahalios On Thursday, September 19, 2002, at 07:40 PM, Prasad wrote: > Does the Prius carry an option switch (a selector) that allows the > driver to > switch between pure electric and hybrid, or is it always 'intelligent'. > Could it be an option that the company can give in the future (if it > is not > available now)? Will the Toyota people listen to the public if such a > modification is required?
