regenerative deceleration

Not true. A lot of that HP from the ICE doesn't go through the mechanical path, but instead gets laundered through the electrical path, MG1 -> inverters -> MG2. So MG2 must be rated to take both the power pulled from MG1, and the power provided by the battery.

A fixed portion of the ICE torque, 72% in the Gen3 (set by the planetary gear ratios), travels through the mechanical path to the wheels. The rest of the torque is provided electrically by MG2. Because power is the product of torque and RPM, the power split varies with the RPM of the various components. And remember that ICE torque is not the same as propulsion torque at the wheels, transmissions are used to magnify torque at lower speeds.

Generally speaking, no.

 

Alex, imho your description of switches between diodes to convert AC to DC current perfectly described a rectifier circuit. A rose by any other name is still a rose. (Shakespeare W.)!

 

Are you responding to something Alex said, or something I said? I remember posting something about the switching H-bridge circuits in the inverter.

A key difference in comparing to a rectifier circuit is, you can build a rectifier circuit out of passive components like diodes and leave it alone, it just sits there and rectifies.

You aren't going to rectify anything with a switch bridge unless you have a computer actively controlling the switches, telling them when to switch, in exact sync with the AC waveform. That's what's going on in the Prius electronics. (Also, be careful never to let both pairs of switches be on at the same time, or the magic smoke quickly escapes.)

Also, the bridge of switches functions equally well as if it were a rectifier (in one direction), or an inverter (in the other direction), again just depending on the timing of the control pulses from the computer. There's a definite elegance to Toyota's design here.

-Chap

 

Alex,

As fuzzy1 points out, you're laboring under a few misconceptions still. It is great that you're trying to climb fast up the learning curve. This aspect of how the Prius works is very little changed, except for some details of voltages and capacities, over the, now, twenty year history of the car, and there's a lot of material explaining it quite well that you'll be able to catch up on if you do just a bit of searching. A lot of it is right here on PriusChat. Then there are things like the Oak Ridge laboratory teardown papers, the writeups by hobbit, and, if you're willing to part with $15, the entire collection of Toyota materials on techinfo.

-Chap

 

Re: #25
Thanks Chap, I've got the picture now. Gone are the days of mullard valves!

 

Hi all,

Let's say you have a planned/regular journey that you know that you are going to exit the highway via long downhill offramp.

Before you exit this offramp(which you know regenerative downhill deceleration will take place), is it a good idea to intentionally drain your Prius battery levels(by forcing EV mode) beforehand to as low as possible(i.e. 30% or less) so that you can recover battery levels going down the downhill offramp. As oppose to the scenario where your battery levels are near full and you just go down this offramp without capturing much energy.

I understand that the new Gen4 can operate on EV mode on higher speeds than previous generations.

 

I'd just drive it. Forcing EV mode achieves little. If you're on the highway, you're well past speeds which will operate in EV mode. My experience with exiting motorways is that you'll pick up about one bar on the off-ramp maximum.

Above all, don't annoy the traffic behind you - that could be much more expensive than the fraction of a cent you might save.

 

I agree with Alan. The Prius is extremely capable of looking after the battery SOC itself. The regeneration you get from coasting is relatively small, at best is when you apply the brakes gently and progressively. I'm feel sure you will come to notice all these things for yourself in time. For now just sit back and enjoy the Prius advantages.

Oh, and keep in touch with all the latest chatter on this site. The people are all warm and friendly and some have a great with of knowledge, but not me sadly.

 

Hi All, thanks for the tips, I am taking delivery to a new Prius(2016 NimH) on December. First time Prius/Hybrid owner but a 5 year full time driver by profession.

I am still learning(reading up on internet) what would be the most effective driving method for Prius(with taking into road courtesy and safety into first consideration). I usually drive at night where there are lesser cars on the road. Don't wish to add to any bad reputation or impression that other road users may have on road hogging hybrid cars.

Would like to ask the experts/experienced owners over here what would be the most optimal fuel saving(safety first) tire pressure for wet/summer conditions. I have gotten a tyre pressure recommendation from a taiwanese youtube review video with these figures, Front: 250kPa(36.2psi) and Back: 220kPa(31.9psi)

 

I haven't noticed an appreciable difference with tyre pressures. The (15") recommendation here is 36 PSI Fr/35 PSI Rear. I tried pushing them up an extra 4PSI and could only notice that the ride was rougher, but fuel use showed no detectable change.

Just drive your PRIUS, get used to it, drive it like you'd drive any other car. Simple things like slowing down gradually coming to RED lights if there's no traffic behind, accelerating moderately - again if there's no traffic behind. The PRIUS will accelerate off the line quite briskly if you need to.