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Has anyone done any testing to identify method to minimize gas used.

When I drive to work, or even doing a 140 km trip with a charge in the middle (I have made this trip purely on EV going the speed limit), but you need cabin heat. I assume the least gas used will be by leaving the car in EV mode and letting the ICE fire up as required to heat the cabin. These trips will be very easy to make without running out of electricity as the ICE is fired up to heat the cabin and charges the battery in the process.

But what about longer trips. I can only assume that propelling the car with the ICE is more efficient than running in pure EV mode and running the ICE to heat the cabin (and charge the batteries). Has anyone done any testing to confirm this?

I ask as this morning it was snowing and I had to run the ICE to keep the windows defrosted. The windows would not defrost with the HVAC on LOW. But the ICE never propelled the car (at least according to the on screen "energy flow"). I left the car in EV mode which is the default mode when starting the car.
 

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If you are in EV mode, when the ICE is started for heat it does not out out enough current to charge the battery. Yes, it does add some, but far less that you're using to move the car. In ICE Heat mode, the engine is roughly idling. This is to minimize the fuel used, I'm sure. I've seen it skew my EV range slightly higher, but not by a lot. It probably adds a mile or so, and likely is just making up for the low temperature loss.

I believe it is more efficient to switch to Hybrid or Sport mode while driving at freeway speed, if you are traveling beyond your EV range and/or you will be doing some non-freeway driving at your destination and want to save the charge for there. My (early) morning commute is 14.6 miles, with about 5 miles on the freeway and another 2 miles still driving fast but with traffic lights. I use HEV to save my range for the afternoon commute home. If the sun's been out I can maybe get by with keeping the cabin heat off longer in the afternoon. I figure if I'm running the ICE for heat, I may as well use HEV mode at freeway speeds.
 

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I believe it is more efficient to switch to Hybrid or Sport mode while driving at freeway speed
A belief system is a great thing, but paying attention in physics class is better. Never more efficient in Sport.

Yes, generally using HEV mode on the highway and reserving EV only for the ends of a trip is more efficient.

As far as heat goes, in this cold weather, my engine fires up right away but stays in EV. Rather than drive in EV with the engine idling, I accelerate briskly. As long as the engine is on, might as well be providing direct motive force. While accelerating briskly on the gas engine may sound inefficient (it is), my HEV shifts into a significantly more efficient gear around 40 mph so there is less time spent with engine rpm higher than optimal. Pretty hard to crunch the math on this, but it seems rational. Side effect of warming the engine up faster which provides heat faster.
 

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I don't have a plug in. In my HEV I have found that the motor does some unexpected things. If in cold weather and I am going to be driving for more than a very short distance (say more than 2 miles) I get far better fuel economy to turn up the heat to force the ICE to run at a highter RPM and not in EV mode all, as it will warm up the motor far more. If I have the heat turned off, the motor will still turn on and go into a low idle mode that won't really warm up the motor to much more than a single pip on the engine temp screen. It is still using gas but can't really produce any heat. If you force the engine to run like a motor should then it warms up pretty fast and gives you heat, and will then shut off totally even if the heater is turned on. As well, once warmed up it has the ability to re-heat iteslf much faster than if you left it in low idle mode.


I found the 2 mile is about the break even point that running the engine at a higher rev level to warm it up faster will give you about the same economy after you get past the 4-5miles driven and save you beyond that point. If you drive less than 2miles then you are far better not to turn on the heat. If you are driving between 2-5miles then its a coin toss.



I can't say how this applies to the PHEV but I can imagine that some of it will also be true in that a warmer engine will save you far more gas in the long run that trying to save fuel by low revs that doesn't really produce any heat. that might work fine around the 60-65f temperature band, but when you get colder it makes no sense to run an engine cold as you loose far more in loss of conversion between the fuel to power than you save from using less fuel but less engine temp.
 

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A belief system is a great thing, but paying attention in physics class is better. Never more efficient in Sport.

Yes, generally using HEV mode on the highway and reserving EV only for the ends of a trip is more efficient.
I concur with that. I only use Sport if I want to control the transmission gear (do this often when climbing long hills, the car chooses too low a gear) or if I'd like the maximum EV range possible at the other end of a long trip. When charging isn't an option at a destination, I'll take the slight impact on MPG to maximize the range I have when I get there. And from my experience it is only a slight hit. But yes, using HEV mode is more economical that Sport.
 

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Seat heaters do not make the ICE run, at least on a HEV.

I rarely ever use the regular heater. Although, I do live where 30 degrees F is about as cold as it ever gets.
 

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Seat heaters do not make the ICE run, at least on a HEV.

I rarely ever use the regular heater. Although, I do live where 30 degrees F is about as cold as it ever gets.
Correct, the seat heaters have no impact on the ICE running. Props to you if you can drive without heat when it gets that cold. We get into the 60s and I need it. Heated socks would help, I suppose, but I hate the thought of trying to power them. :D
 

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Seat heaters do not make the ICE run, at least on a HEV.

I rarely ever use the regular heater. Although, I do live where 30 degrees F is about as cold as it ever gets.

The bigger problem i find around those temperatures is fogging of the windows. if you get the glass being cold and your breath is warm then it will fog inside the window. the only way to get rid of that is to run air over it and that means you are turning on the heating. Funny, you suffer far less with it in the really cold winter. I think it might be because the air si much dryer and absorbs any of the moisture from your breath.
 

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Seat heaters do not make the ICE run, at least on a HEV.
When the battery is depleted, the ICE runs. What depletes the battery? Any use of electricity, including seat heaters.

Of course, seat heaters are still more economical on a number of trip types, especially short ones, that forcing the ICE to run for waste heat from burning gas.
 

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Some of the battery management logic is really hard to fathom. Here are some examples:

I assume that the electric seats are heated by the 12V battery, not the high voltage battery. I'm assuming this because there's an obvious safety concern if you energize the heated seats, have something sharp on the seat that punctures the seat and shorts the heater wire, and it's running high voltage, but that wouldn't be a safety concern if it was a 12V system (instead, it would just be a bummer for the car owner). And yet, I can drive my PHEV around with the electric seats energized and so long as I have EV range showing on the instrument cluster, the ICE never starts, and my estimated EV range doesn't change when I turn them on or off.

Having the electric seats turned on doesn't affect my estimated EV range as shown on the instrument cluster. But having the fan on (even when the AC is not engaged and the fan is just blowing ambient air) reduces my estimated EV range. Who knew that an electric fan consumed more energy than an electric seat heater or an AC pump?

I can drive down the road all day listening to the radio (and with most other accessories turned off), and so long as I have EV range showing on the instrument cluster, the ICE won't start. But if I stop and sit in the car, in Park, listening to the radio: if the car is Off (or in Accessory), I start getting alerts on the head unit after about 1 minute that I'm at risk of running down the battery. If the car is On when I'm stopped and in park and listening to the radio, then after a few minutes it might start the ICE. How is this different from driving on the highway and listening to the radio (when it doesn't need to start the ICE)?

I also have (limited) experience sitting in a parking lot with the car On, with no radio, but with the AC running (and with ample EV range on the instrument cluster). It's happy to sit there and run the AC and never start the ICE. But God Forbid that I should turn on the radio...

Am I imagining this? Does anyone else have a different experience with some of the less-common cases that I've just described?
 

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Some of the battery management logic is really hard to fathom. Here are some examples:

I assume that the electric seats are heated by the 12V battery, not the high voltage battery. I'm assuming this because there's an obvious safety concern if you energize the heated seats, have something sharp on the seat that punctures the seat and shorts the heater wire, and it's running high voltage, but that wouldn't be a safety concern if it was a 12V system (instead, it would just be a bummer for the car owner). And yet, I can drive my PHEV around with the electric seats energized and so long as I have EV range showing on the instrument cluster, the ICE never starts, and my estimated EV range doesn't change when I turn them on or off.

Having the electric seats turned on doesn't affect my estimated EV range as shown on the instrument cluster. But having the fan on (even when the AC is not engaged and the fan is just blowing ambient air) reduces my estimated EV range. Who knew that an electric fan consumed more energy than an electric seat heater or an AC pump?

I can drive down the road all day listening to the radio (and with most other accessories turned off), and so long as I have EV range showing on the instrument cluster, the ICE won't start. But if I stop and sit in the car, in Park, listening to the radio: if the car is Off (or in Accessory), I start getting alerts on the head unit after about 1 minute that I'm at risk of running down the battery. If the car is On when I'm stopped and in park and listening to the radio, then after a few minutes it might start the ICE. How is this different from driving on the highway and listening to the radio (when it doesn't need to start the ICE)?

I also have (limited) experience sitting in a parking lot with the car On, with no radio, but with the AC running (and with ample EV range on the instrument cluster). It's happy to sit there and run the AC and never start the ICE. But God Forbid that I should turn on the radio...

Am I imagining this? Does anyone else have a different experience with some of the less-common cases that I've just described?
When the car is "running", the 12v battery is kept charged from the traction battery. So there's no issue with seat heaters or running the radio draining the 12v battery. When you are in accessory mode, the traction battery is disconnected from the 12v system. The PHEV has an extremely small 12v battery, so the car warns you not to use the accessory mode for a long period of time.

The logic that controls the range meter isn't programmed at a level to recognize the HVAC is only running the fan, so it takes the worst case power usage (full A/C mode) and reduces the range display. I have never had the ICE come on while sitting still unless it calls for heat or the traction battery has dropped to about 16%. Using the radio has no effect on that, because it uses far too little power to make a noticeable difference. I can't explain why your ICE is coming on with radio use, because it shouldn't unless the traction battery is depleted.

When you're in accessory mode, you are using a very tiny 12v battery to run the entertainment system. That's why you get the alert to put the car in "running" mode. It doesn't take much to drain that 12v battery below what is needed to run the car. Yes, it's that small. :)
 

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When the battery is depleted, the ICE runs. What depletes the battery? Any use of electricity, including seat heaters.

Of course, seat heaters are still more economical on a number of trip types, especially short ones, that forcing the ICE to run for waste heat from burning gas.
Well, sure, it you want to get technical about it. :D

I believe the comment is just that as long as the traction battery has sufficient charge, just turning on the seat heaters will not require the ICE starting. Same with the A/C, radio or the heated steering wheel. It's all dependent on the SoC of the traction battery.
 

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Has anyone done any testing to identify method to minimize gas used.

I ask as this morning it was snowing and I had to run the ICE to keep the windows defrosted. The windows would not defrost with the HVAC on LOW. But the ICE never propelled the car (at least according to the on screen "energy flow"). I left the car in EV mode which is the default mode when starting the car.

Yes, i have made a test this morning. Made a small 40km trip, and i have left on EV mode. Powered the ventilation and set it too 27.0c. After, the thermal engine started up and took 3-4 minutes to get the heat. After, i have turn down the tempareture level too 22.5c, and the thermal engine shutted off, and powered up to regain the temperature. etc...



The only thing that is bizzare that "made me go HUMM!!!!", is that the temperature gauge does not go up on EV mode even if the thermal engine powers up for heating.!
ex: After 10km on small roads, when i got on the highway and switch on the HEV system, it took 30 sec. to display the normal temperature on the gauge.! kind of weird.! :confused:
 

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