[theQball80]

In EV mode, seems when I pull away at a light and push the throttle as much as I can before kicking in the ICE engine that it goes to about 40kmh and then lets up, and then again around 65kmh. Is there a fake "shift"? Or is the Electric motor going through the 6 spd transmission or directly driving the wheels?

 

[Mikek7]

The electric motor is going through the 6spd transmission and the car actually shifting.

 

[atc98092]

Yeah, it's not fake shifting. The EV motor goes through a true dual clutch transmission, and you are feeling actual shifts. That's because the EV motor in the PHEV is only 60 HP, and sometimes needs the torque multiplication of the lower gear to climb hills. I feel it all the time, as I live on a pretty steep, tall hill, and it can't maintain speed, let alone accelerate, without shifting down a gear from whatever gear the EV mode generally uses.

 

[yticolev]

I don't think the electric motor needs torque multiplication. If the DCT doesn't shift, it would be very clunky to quickly engage the engine as needed. Engine rpm needs to match with the correct gear for the wheel rpm. So it only makes sense for hybrids (including PHEVs) to be in the correct gear for that to happen in less than one second and smoothly.

Here is the layout:

Engine > engine clutch > motor > dual clutch transmission > wheels.

 

[atc98092]

All I can say is after the downshift, acceleration increases while the power meter shows a decrease in power used, so that seems that it's making use of the torque multiplication from the lower gear.

 

[yticolev]

All I can say is after the downshift, acceleration increases while the power meter shows a decrease in power used, so that seems that it's making use of the torque multiplication from the lower gear.

That could be an artifact of how pedal position reacts to a specific gear - all of which is controlled by a computer so not necessarily linear. In any case, simple physics suggests that an increase in acceleration results in more power being used, not less.

Not denying your perception, but it doesn't make sense to me. I've felt something similar, crawling up a hill at less than 20 mph in EV (hybrid) and a downshift (while slowing down) seems to cause car to surge. I've never happened to note what the power meter is doing.

 

[atc98092]

That could be an artifact of how pedal position reacts to a specific gear - all of which is controlled by a computer so not necessarily linear. In any case, simple physics suggests that an increase in acceleration results in more power being used, not less.

Not denying your perception, but it doesn't make sense to me. I've felt something similar, crawling up a hill at less than 20 mph in EV (hybrid) and a downshift (while slowing down) seems to cause car to surge. I've never happened to note what the power meter is doing.

Nope, not changing the pedal pressure at all. The car downshifts and acceleration increases while the power meter drops a bit. I'm maintaining a specific pedal pressure, because anything harder would fire up the ICE.

 

[Griswald]

You may not have changed anything, but the thousands of lines of embedded code surely did.

I know what you mean, though. It does feel different.

 

[dand]

It feels to me (2019 PHEV) that in EV-mode the car uses two, maybe three gear ratios, usually shifting initially at around 20mph. From what I gather, even electric motors can benefit from variable transmission ratios in terms of efficiency: https://cleantechnica.com/2019/07/22/ev-transmissions-are-coming-and-its-a-good-thing/

 

[atc98092]

I typically only feel a shift when climbing a hill and I'm at the upper limit of EV power. I can't say I've ever felt an upshift in EV mode. I would agree that EV mode uses a most three gears, and perhaps only two under typical conditions.

 

[yticolev]

If you are driving at highway speeds, you will be in sixth gear in EV mode.

 

[yticolev]

From what I gather, even electric motors can benefit from variable transmission ratios in terms of efficiency: https://cleantechnica.com/2019/07/22/ev-transmissions-are-coming-and-its-a-good-thing/

Not much point for ordinary single motor BEVs, advantage mostly track or autobahn. In dual motor Teslas, they actually have two different designs of motors front and rear. One for good acceleration, other for better efficiency. Trade off as fits circumstances (or both). Hadn't heard the bit about different ratios for each before, but that is interesting.

 

[atc98092]

The only existing EV with more than one gear in the transmission is the Porsche Taycan, which has a two speed. Tesla experimented with them in the original Roadster, but ultimately dropped it as not worth the effort. I agree with @yticolev that it would really only be a benefit on the Autobahn. With the highest (legal) speed limit in North America at 80-85 MPH, there's not much benefit for the expense.

 

[91cavgt]

85 mph is the highest speed limit as it is about 25 miles from my house!! The Texas Autobahn can be a lot of fun!!!

As to shifting in EV mode, I’ve drive my HEV 2018 model from a dead stop to 65 mph before the gas motor turned on(had to get the battery up to 100% and be very light on the throttle to do this) and I felt every gear change, 1-6. Granted, in normal driving I too feel about the same, as though primarily only 3 gears as being used.