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Question re: "Power Split (i.e., hybrid) Mode"

7K views 11 replies 11 participants last post by  longflare 
#1 · (Edited)
My Volt and I just celebrated our first anniversary, and most of our 5,000 miles together have been all-electric. I do have a few hundred miles on ICE, and I've always been curious as to whether the transition to Power Split Mode, i.e., when the ICE provides some torque directly to the drivetrain, is detectable to the driver via a change in engine noise, throttle response, DIC-indicated kW draw, etc. As with all the drive mode transitions it was designed to be "transparent," and I've never been able to detect it. But is it perceptible in any way, other than using an OBDII?
 
#2 ·
If you are cruising at a steady speed for more than a few seconds, and suddenly step on the throttle, and notice a half second "pause" before the Volt accelerates, that is because you were in the "eco" overdrive mode, as I call it. The car has to declutch the motors from the overdrive mode, spin the bigger electric motor up to the the proper RPM, then engage the "normal" mode clutches, before the car can accelerate hard.
 
#3 ·
..., and I've always been curious as to whether the transition to Power Split Mode, i.e., when the ICE provides some torque directly to the drivetrain, is detectable to the driver via a change in engine noise, throttle response, DIC-indicated kW draw, etc. ...?

note that SharkVolts answer, while correct, applies to 2-motor mode whether running all electric or in charge sustain mode ( with the generator running) it does allow you to know that the car "was" in 2 motor mode. but not the entry. I have not been able to detect the transition either through sound or physical feel, but, if you have a 2013 or newer, you can detect based on the power flow meter in the driver's instrument cluster. usually when running in 2 motor mode with the generator on, the power split will show reduced current flow, and in many conditions will shows a small power flow into the battery and reduced power flow from the generator. in series hybrid mode, the generator power flows are higher and the larger electric motor power flow is higher also.
 
#9 ·
....if you have a 2013 or newer, you can detect based on the power flow meter in the driver's instrument cluster. usually when running in 2 motor mode with the generator on, the power split will show reduced current flow, and in many conditions will shows a small power flow into the battery and reduced power flow from the generator.....
If you listen carefully and you accelerate very gradually from 30 mph with the gas engine running up to 45 mph you should hear the rpm of the engine drop as it transitions from series mode to power-split mode within a few mph after you pass through 36 mph.
Thanks, all, for this info!
 
#7 ·
I'd say that like everything else on the Volt "it depends". If I'm doing a steady 65 MPH or less, or not pushing it hard, I can't tell other than the visual. But if you have to push the engine then there is a lot of harshness. At low speeds I can always tell. It's just more noisy.
 
#8 ·
If you have 2013 or newer, you can watch the powerflow in the driver dash which shows kw produced/consumed. As the car enters parallel hybrid mode, you will see the engine producing less energy (current). Or you could use TorquePro and create a dashboard which shows this info in great detail on your phone. However, I would rather pay attention to the road.
 
#10 ·
Leave the power meter showing and as you accel to speed and ease off, at some point between straight-away and after-4-minutes, the engine power will drop momentarily as the battery draw increases, then it comes back up again. This is where the engine has disengaged from MGA, which then engages with MGB through the epicyclic, and then MGA and the engine are brought back up to speed.
 
#12 ·
I've noticed too, that the power scale indicating ICE output, drops almost to nil, (seeming like the ICE is about to switch off), then it comes back up. I hadn't noticed any sound or change in acceleration or speed that accompanies this.
A few times, I had increased throttle setting moments after noticing this, and then experienced the de-clutching for power process previously mentioned. (like an auto kicking down)
 
#11 ·
I've discovered in my 2013, that if you can get it to hook in at residential speed (~35 mph) while in Drive and gently ease off the accelerator pedal, you can feel the generator pulling the car (instead of decelerating) for few tenths of a mile before it disengages and the car coasts. It almost feels like the cruise control is set when it does that. I notice it on my block when i'm coming home in CS mode.
 
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