Can someone explain to me how an electric motor can produce much more torque than a conventional ICE? With our Prius, the electric motor puts out 295 lbft...I think up to 3000rpm?? if I combined torque from the ICE in the Prius, I get over 370 lbft of torque. Is this right? So from a stop light I can probably beat most cars across the intersection until I reach peak torque a few seconds/minutes latter. How long will it take to reach peak torque? I am no mechanic so I am a bit naive about this stuff... Thanks.
This is the synergy of the gas electric hybrid. The ICE and electric motor have complementary torque characteristics. The ICE is at its worst at low RPM's but that is where the electric motor has its best torque. (It is 295 Ft-Lb 0-1200 RPM. This approaches what a Toyota V8 produces at a few thousand RPM.) As for the combined torque, you cannot just add the two values. There is a complex relationship of the electric motors torque curve combined with the ICE's torque curve through the effective gear ratio of the power split device. The Toyota engineers would know what is the peak torque of the Prius drive. As far as I know it is not publicly published.
Visit http://www.toyota.co.jp/en/tech/environment/index.html Click on THS II. Some of the pages there have relevant info although not a torque versus speed curve.
Pretty peekture.. [Broken External Image]:http://www.toyota.co.jp/en/tech/environment/hsd/image/graph-how_works-white_large.gif
To understand the relationship between the Prius motor torque and a conventional car engine, you need to understand the way it is configured. A typical engine has a final drive ratio of about 3.75:1. There is also a transmission with ratios of about 3:1, 2:1, 1:1, and .85:1 for 1st, 2nd, 3rd, and 4th gears respectively for an automatic. Note that 4th gear is overdriven. While the Prius has a final drive ratio of about 4:1, the electric motorg is essentially direct drive, bypassing the CVT which the ICE passes through. As such, the 295 lb-ft in the Prius is not multiplied through the transmission (times 3 plus torque convertor multiplication factor in 1st gear) as is done in a conventional vehicle. As a result, there is somewhat of a misrepresentation. The 295 lb-ft is available, but it is not multiplied like a conventional vehicle through the transmission and therefore does not result in the tire burning affect that one might expect. The motor behaves as though you were driving along in 4th gear all the time, or 5th or 6th gear if you have a manual transmission.
