Good afternoon Having read the PHV Prius specs, I now have a question... 100km/h (62mph~) is the limit for EV mode - 12miles travel. I wonder PSD has changed, because on our 3rd Gen the practical limit for EV travelling (stealth) is 45mph~, and needs quite a spin by MG#1...and I personally have in doubt that PHV ICE has to be in motion when you need to avoid any kind of losses. Has PSD effectively been modified for this PHV model to come?
We asked that very question when we were test driving the PHV. There is no mechanical difference. I know what you're thinking because we all said it as soon as we heard it, "if there's no difference between the Gen3 and the PHV, let's figure out how to hack the Gen3 to give 65MPH EV." Go for it.
I was not thinking of hacking my SnowWhite 3Gen Instead, just curiousity over the ICE/PSD behaviour between 45 and 65 MPH on the PHV... Thank you very much for your answer. It is a surprise that this means ICE spining being propelled by EV, reducing by far(?) the EV range...
At 65 MPH, ICE does not have to spin. Toyota use 62 MPH to be conservative. Above that speed, ICE need to spin to protect MG1 from over-spinning. You want to use ICE above that speed on the highway anyway.
Interesting. My understanding is that above 45 MPH, with the current Prius, the ICE starts to spin. Why has Toyota capped this “glide” mode (electric only without ICE turning) to 45 MPH? I thought it was to limit MG1 RPM? Do you imply MG1 can safely turn faster (up to 65 MPH) but is prevented to do so by current programming and that the PHEV will be configured in a different manner? What would be the explanation for the current 45 MPH limit? Simply to keep a good system efficiency (avoid drawing too much power from the battery)?
45 MPH is software limit. Gen2 Prius was limited to 42 MPH. Hardware limit based on maximum allowed MG1 RPM is 65 MPH. We don't have data on how long that max can be kept at.
Hum. We'll see what the impact will be on reversed engineering PHEV kits for the current Gen III by third parties. It seems they will need to trick few things (if even all possible): battery SOC, change the max speed EV limit, make the car believe it can get more than 27kW from the "traction battery", etc.
Yesterday I downloaded the simulator of PSD. Did find no chance of ICE 0rpm over 51MPH. So the simulator is along to the software limits.
Make sure the simulator supports gen2 Prius (HSD). THS is gen1 Prius. MG1 max for gen1 Prius is 6,500 RPM. For gen2 and gen3, max is 10,000 RPM.
So the change from 42 MPH to 45 MPH from Gen II to Gen III is simply due to a software change or to a final gearing of the PSD to wheels, rather to a different MG1 speed?
We know PSD ratio and MG1 max speed (no mention of the change) remain the same from Gen2 to Gen3. It has to be the software change to allow 45 MPH in Gen3. Gen3 also has electric water pump which probably made it safer. The only change in Gen3 was MG2. MG2 spins about twice faster with about half the torque but they added speed reduction unit (torque multiplier). The end result was smaller, lighter and more powerful MG2 even with the extra set of planetary gearset.
Thanks for the clarification but this brings a new question: I knew about MG2 size reduction and its new torque multiplier and I understand the basics of the epicyclic gear, but how can they multiply MG2 torque exactly? Where is MG2 physically attached? I thought it was fixed to the ring gear (in line with the ICE and MG2), but that can't be...? Is it in the middle of the reduction gears to the wheels?
So, with a suitable sized converter (~10kw?) and a large battery pack (10kwh?) and a flash of software to allow EV mode up to 65mph (which seems fine, MG1 can cope, and MG2 while not massively powerful can get you there eventually. my first car only had 60hp or so [geo metro/suzuki swift] so 80hp seems doable) you've basically got an extended rage electric vehicle a la volt, with petrol "range extender". Or i wonder if it will be as simple as buying the official PHEV packs and ECU, and plugging it into an exisiting G3...
The key is can you get the software change. This would include more changes to software to be able to lock it to ev mode (otherwise your normal accelleration would kick it into hybrid engine mode. It also has a different inverter, fan, and likely other hardware. You will end up spending more than a volt and voided your warenty. I wish toyota would make this easier. It appears that the only way is to have one of the kit makers crack the software and make the extended range pack.
The same way a low torque MG1 can start the ICE. When the car is at rest and if the MG1 (sun gear) spins, it turns the ICE (planet carrier) but at slower speed; achieving torque multiplication. It looks like this (animation from Graham Davis): Take another Planetary gearset and put MG2 at the sun and ground the ring gear. The output from the planet carrier would multiply MG2 torque. Both of these Planetary gearsets are connected like below. Blue is MG1, Red is MG2 and Gold is PSD+SRU. Everything is very cleverly packaged.
The wheels are 2.09% larger (195/65 R15 vs 185/65 R15) and the final drive ratio was changed. I'm seeing reports of 2010 = 3.267:1 and 2004 = 3.46:1, so the hub is rotating 5.9% faster. Combining these two for a previous road speed of 42mph = 45.4mph. That means that with every other ratio remaining the same, MG1's maximum permitted speed is the same as before.
