No HVB charging while in reverse or neutral?

[ptek]

I'm curious if anyone has an explanation for why the HVB doesn't charge when the gear selector is in neutral or reverse?

 

I've noticed that when the ICE is running, whenever I shift into neutral the HVB status (left screen) immediately switches to the down arrow indicating HVB battery discharge. This happens if the car is moving or is stopped. When stopped, when I shift from neutral to park, the HVB status immediately displays the up arrow. It doesn't seem like there would be any difference in the ICE/MG1/MG2 interactions between neutral (stopped) and park, yet park charges and neutral doesn't.

 

For reverse, I've noticed that as I start to back out of the garage, the HVB up arrow is displayed, so the car starts out charging the HVB. (The HVB is at about 25% charge.) I have a rather long driveway and it takes about 30 seconds to slowly back down it. After about 15 seconds, the HVB display switches to the down arrow and I haven't seen it switch back to charging, even if I have to wait for a minute for traffic to clear before backing out into the street. As I'm sitting there not moving with the ICE running, I had been thinking that "at least the HVB is being charged", but now I'm realizing that its not. I've started shifting from reverse to park if I have to wait.

[VonoreTn]

I have 2 comments, possibly neither are relevant or useful, given that my FFH is going on 5 years old now. Number 1, there could be something wrong with your FFH given that you have only averaged 35 mpg after 11 fillups, I have never averaged close to that low for 11 fillups, and I have kept 100% fillup data for the full 89K miles. I can send you my data record if you are interested, it's an MS Exel file. My overall average is 39 mpg, a little less in the winter, more in the summer. Plus your 2014 is supposed to get significantly better mpg than mine. My last tank of gas FE was 41.6 mpg, which was rural driving, maybe 50 mph average.

 

But now that I notice you live in Minnesota, I need to soften my first comment, I think I would also be averaging about 35 over this last winter in Minnesota, cold definitely hurts the FFH mpg. Heavy rain and snow definitely increase the vehicle rolling resistance. I think you will be pleasantly surprised as warm weather occurs. Also if you drive a lot at 75 mph, that would also yield 35 mpg on my FFH. Being retired, I am rarely in a hurry and only occasionally drive 75 mph anymore. That was the first comment.

 

My second comment is my experience which is totally not understood by me, which is for awhile I was switching into neutral while driving, thinking that it would improve my mileage, like less drag when going down hill. First, it did not. I think for optimum mpg you need to stick with the programmed strategy, which I'm pretty sure does not include the driver putting the vehicle in neutral while driving. Secondly I started using oil, I would be over a quart low well before the 10K oil change interval. So I stopped putting it in neutral, and now I do not consume any engine oil. At 10K miles it still has full oil level. I do not understand that at all but I am 90% confident of the correlation of excess oil consumption and using neutral at speed. Maybe someone at Ford more familiar with the hybrid engine/tranny/computer mechanism has a clue about the oil consumption. There are no fluid leaks on my garage floor, thus all that oil must have been going out the exhaust, which would not be a good thing. It might be related to an engine code I was getting occasionally, with the engine warning light, PO130, which is the upper oxygen sensor. I never replaced it, and the code and light has stayed off since I turned it off awhile back with my OBD2 meter.

Edited March 22, 2014 by VonoreTn

[corncobs]

I can't comment on the neutral condition but the other part seems pretty normal to me.

We the PCM update the car startup (first mile) has changed in terms of running the ICE and charging or not charging the HVB.

 

Whenever I leave home or office it usually starts with EV. As soon you need to get going entering a main road the ICE kicks in but the arrow is still pointing down. Sometimes to a very low SOC level before the computer switches to charging.

 

I believe that was done to take load off the ICE when cold and run more on EV power assisted as long as possible.

 

HB might have a more technical explaination for this phenomenon.

[murphy]

The car does not use the ICE to move the car when in reverse even if it is running. Reverse is only done with electric drive. It is trivial to reverse the electric drive motor. Doing reverse with the ICE would require additional gears that would be wasted weight most of the time. I forget where I learned this but it may have been in the videos that show how the eCVT is put together.

[ptek]

Interesting comments, thanks.

 

VonoreTn, as you later suspected, I think 35 MPG is not unusual - car purchased in the dead of a MN winter and driving mostly on 55 - 70 MPH roads. My average is starting to climb and I'm starting to hit the upper 30s to low 40s now that the weather is warming. Oil consumption due to coasting in neutral does sound strange. Fortunately, I haven't done it regularly. Just here and there as a test. Your experience sounds like a good reason not to do it.

 

Corncobs, when I leave the driveway, I pull out onto a 55 MPH road, so I'm not real easy on the accelerator. The ICE is already running due to the heater setting, and the HVB starts charging as soon as I move the selector to drive. I haven't noticed the car favoring EV in drive when cold. That certainly could explain what's happening in reverse where the speeds are much slower and can be handled by EV.

 

Murphy, I know that propulsion in reverse is provided by the electric motor. I was just surprised that the ICE doesn't charge the HVB while running due to the heater setting. Keeping the engine load low makes as much sense as anything, I guess.

 

Thanks again.

[hybridbear]

Interesting comments, thanks.

 

VonoreTn, as you later suspected, I think 35 MPG is not unusual - car purchased in the dead of a MN winter and driving mostly on 55 - 70 MPH roads. My average is starting to climb and I'm starting to hit the upper 30s to low 40s now that the weather is warming. Oil consumption due to coasting in neutral does sound strange. Fortunately, I haven't done it regularly. Just here and there as a test. Your experience sounds like a good reason not to do it.

 

Corncobs, when I leave the driveway, I pull out onto a 55 MPH road, so I'm not real easy on the accelerator. The ICE is already running due to the heater setting, and the HVB starts charging as soon as I move the selector to drive. I haven't noticed the car favoring EV in drive when cold. That certainly could explain what's happening in reverse where the speeds are much slower and can be handled by EV.

 

Murphy, I know that propulsion in reverse is provided by the electric motor. I was just surprised that the ICE doesn't charge the HVB while running due to the heater setting. Keeping the engine load low makes as much sense as anything, I guess.

 

Thanks again.

A couple comments/questions:

1. Why does your ICE come on so early? It shouldn't come on for the first time until you're actually driving away moving forward. Backing down a driveway shouldn't trigger the ICE? If you're causing it to come on by turning on the HVAC then I'd recommend leaving the HVAC off until you're done with reverse.
2. The ICE cannot charge the battery when in reverse because of how the gears mesh of the traction motor, generator motor and ICE driveshaft. Reverse propulsion is done with the traction motor and because of the direction that the gears are spinning you cannot use the ICE to charge the HVB because the gears would be fighting against each other. The car is designed to only charge the HVB when in Park or Drive. You also lose HVB charging if you put the car in Neutral with the ICE running. Toyota hybrids operate the same way.
3. Read this thread for info about more efficient warm-up. Forcing the car to not use up the HVB while running the ICE at a low power demand will save you fuel. Making sure that the first acceleration up to 55 MPH happens with the ICE instead of the electric motor and the ICE idling will warm up the ICE much faster and will conserve fuel.

[tr7driver]

My ice always comes on when I back out of the garage, and my driveway is down hill, so I'm putting my foot on the brake while I'm backing out.

[hybridbear]

My ice always comes on when I back out of the garage, and my driveway is down hill, so I'm putting my foot on the brake while I'm backing out.

Do you leave your HVAC system on when turning the car off? The HVAC will trigger the ICE to activate almost immediately. Turning off the HVAC before powering down the car will prevent that and can lead to overall much more efficient operation by better managing battery use than the car can do on its own.

[tr7driver]

I guess it is usually on auto, so it would be on. I'll have to try it turned off.

[lolder]

The ICE comes on because it's doing the start up checks or any other of the many reasons it comes on. The ICE CAN charge the HVB in R but even if it is running it cannot move the car in R, only the traction motor can. Back out, leave it in R until the ICE quits, then hit the gas. The acceleration is robust and EV only and the ICE won't start if the SOC is high enough. HVAC in Auto when it's cold will cause the ICE to run but not always when the OAT is hot.

[ptek]

 

1. Why does your ICE come on so early? It shouldn't come on for the first time until you're actually driving away moving forward. Backing down a driveway shouldn't trigger the ICE? If you're causing it to come on by turning on the HVAC then I'd recommend leaving the HVAC off until you're done with reverse.

 

Yes, I leave the HVAC on and the ICE starts almost immediately. Since the HVB is typically low from returning home the night before in EV+ mode, my thought had been that the ICE can warm up and charge the HVB at the same time. Now that I see that the HVB isn't being charged, I will rethink that. I will try turning off the HVAC and see if the ICE still starts.

 

 

The ICE cannot charge the battery when in reverse because of how the gears mesh of the traction motor, generator motor and ICE driveshaft.

 

The HVB is charging for the first 15 seconds or so after selecting reverse, even after I start moving. Then it switches to discharge.

 

 

Read this thread for info about more efficient warm-up. Forcing the car to not use up the HVB while running the ICE at a low power demand will save you fuel. Making sure that the first acceleration up to 55 MPH happens with the ICE instead of the electric motor and the ICE idling will warm up the ICE much faster and will conserve fuel.

 

I assume the car is in S1a while I'm reversing down the driveway. It has been cold enough that the ICE has always run due to the heater setting. The ICE has always been on as I shift to drive and accelerate to highway speeds. I think I've only observed S0 (EV at startup) 2 or 3 times. That was when leaving work after a 40+ F daytime high temperature.

[hybridbear]

 

Yes, I leave the HVAC on and the ICE starts almost immediately. Since the HVB is typically low from returning home the night before in EV+ mode, my thought had been that the ICE can warm up and charge the HVB at the same time. Now that I see that the HVB isn't being charged, I will rethink that. I will try turning off the HVAC and see if the ICE still starts.

 

 

The HVB is charging for the first 15 seconds or so after selecting reverse, even after I start moving. Then it switches to discharge.

 

 

I assume the car is in S1a while I'm reversing down the driveway. It has been cold enough that the ICE has always run due to the heater setting. The ICE has always been on as I shift to drive and accelerate to highway speeds. I think I've only observed S0 (EV at startup) 2 or 3 times. That was when leaving work after a 40+ F daytime high temperature.

In S1a the HVB will show charging because the ICE is spinning the generator enough to put out about 2-3 amps of charge into the HVB. The arrow quickly switches to discharging because as you move you quickly demand more than 2-3 amps worth of current from the HVB. Under normal operation the ICE will power the car and send 30-35 amps back to the battery when running most efficiently.

[ptek]

In S1a the HVB will show charging because the ICE is spinning the generator enough to put out about 2-3 amps of charge into the HVB. The arrow quickly switches to discharging because as you move you quickly demand more than 2-3 amps worth of current from the HVB. Under normal operation the ICE will power the car and send 30-35 amps back to the battery when running most efficiently.

I can check the HVB charge/discharge current with the Torque app. I just got my android tablet today.