C Max acceleration question

[BoxKing101]

Hello I’m Isaac and I have a 2013 Ford C-Max and I love it!  I have noticed recently though that when accelerating the computers are choosing the electric drive to run the acceleration while the gas engine takes a while.  I keep my driver view on the engage page so I can see the engine and electric and even while the engine is running its choosing the electric engine to do acceleration.  Anyone else dealt with something like this?? 
 

thank you!  

[stolenmoment]

I'm a happy 2013 Energi owner, and the theorizing around here is that electric motor has quicker acceleration than the gas engine (much less mass to spin, magnetic fields move at lightspeed as opposed to the slower chemical reaction of burning fossils pushing pistons to spin the crankshaft, etc), so it comes up first, then they reach some sort of equilibrium with both contributing.  In general, a gas engine is at its least efficient when accelerating, so it makes sense for the electric to contribute as much as is practical.

[cr08]

On 3/27/2021 at 12:08 PM, BoxKing101 said:

Hello I’m Isaac and I have a 2013 Ford C-Max and I love it!  I have noticed recently though that when accelerating the computers are choosing the electric drive to run the acceleration while the gas engine takes a while.  I keep my driver view on the engage page so I can see the engine and electric and even while the engine is running its choosing the electric engine to do acceleration.  Anyone else dealt with something like this?? 
 

thank you!  

One thing to keep in mind is if the ICE -JUST- started and is cold, the car is going to prefer to let it idle and warm up without a load before it has it contributing to propulsion of the vehicle. Cases that will override this are heavier acceleration or low HVB level as examples. But under mild to moderate accelerator application it will have the electric motor do the lions share of acceleration until the ICE is ready to go (read: All the normal cold start emissions checks are done, O2 sensors are happy, etc..)

Edited March 28, 2021 by cr08

[fbov]

There are two things going on. 

 

Cold start mode

For emission reasons, the ICE runs at low RPM producing little power for ~20-30 sec after ICE first starts. This is sometimes engaged after long downhill runs with ICE off. This is a very different, but short-lived, warm-up mode. 

Hybrid mode

Once cold start's over, the car balances EV and ICE output, based on HVB charge and your throttle foot. I wonder if you're describing normal hybrid-mode operation. As I recall, there are four hybrid modes. Add in the effect of HVB SOC to change the ICE/EV balance and it covers pretty much everything. 

- ICE only

- EV only

- EV + ICE

- EV - ICE (negative split mode)

This last one is a unique case of high MPG with ICE running - negative split mode. It only occurs when HVB SOC is very high, and your throttle foot very light. The "charging" motor acts to slow the ICE RPM, so fuel use falls as mileage soars, but the ICE keeps running. Not common, but neat when it happens. 

 

As to which accelerates faster, EV or ICE, it's a bit of a red herring. In a power-split based hybrid, ICE speed is mostly constant. It operates as a "stationary engine" running any RPM required to generate the requested power. When I start from stop, the engine speed levels off as the car begins to roll, and stays constant until I back off at cruising speed. To anyone accustomed to shifting a manual, constant engine speed is a big change.  

[Cynthia]

I have a 2014 energi.  I wonder if this normal interaction between ice and EV is what I’m experiencing.  For the past year at freeway speeds I hear a sound like I’m accelerating with increasing rpm but no acceleration happens.  It occurs every 10 min on average.  Improved when the transmission fluid topped off but now happening again.  It’s now at the ford dealership and they have found nothing wrong and have driven it 60plus miles.  Even on the freeway.  Any ideas what my sound may be?  I’ve driven the car since 2015 and it is a new sound .  Thanks