MPG "The Perfect Method"

I agree. It seems like an accounting trick that makes certain stats look better but isn't truly more efficient.

 

+1

 

That is using the ICE to indirectly charge, if regen happens on the downhills, the ICE provided power to clime which regen then put into the battery. That is an example of an accounting trick.

Being a fact does not mean its not an accounting trick. The real question is does this actually improve efficiency or its it just shifting data around (in terms of EV/HV miles) while being about as efficient as normal driving. As someone that looked at MM games in the Volt, I'm used to trying to figure out what is real efficiency and what is just apparent gains. 91MPG over 131 miles is good, but it was also effectively down hill. I posted earlier the overall MPG number might work out with this just being an accounting trick. It might also be a real efficiency gain, we just don't have enough data to reach a meaningful conclusion.

I also note you never explained the discrepancy with the first post saying you only did this technique for 20 miles.

 

Yes, you did. Going down hills and charging the battery gets its energy from the gas you used to get up the hill in the first place. Anything after the 5.5 kWh you got from dropping 4500 feet, came indirectly from the gas tank.

 

I would agree that mpg over distance + net kwh from the wall used is a reasonable metric. Basically, how much gasoline was used, and how much electricity from the grid was used.

If this was clarified in some intermediate post, I'm sorry I missed it, but are you saying that you traveled 137 miles round trip between Sacramento and Tahoe, and the display indicates that you got 91mpg with essentially no net electricity consumption (assuming you started "full", ended almost "full", and didn't plug in any time during the trip)?

I just can't get my mind around how the technique of HV up hills, EV down hills and flats, can possibly have any significant effect on overall fuel (gasoline+electricity) consumption.

 

I don't think being rude is going to allow you to break the laws of physics, even if they are 'theoretical'. Give up on your vision of your 'perfect method' and you might be able to learn something from all the experienced people on PriusChat.

 

Bielinsk,

If the ICE is already up to temp, when it switches to HV, it will use no battery.
Switching to HV with a cold ICE will use up battery until the ICE is up to temp.

So if you're planning to exceed 62 mpg on a highway, it's best to manually switch to HV or just step on the Gas while in EV to get the ICE to start on a flat road a mile or so before getting to the highway.

 

Of course you are going to get great gas mileage coming home from the Reno/Tahoe area. It's mostly downhill with little need to use the gas engine. And you've started out with a full EV charge. I'd be more interested to know what your MPG was for the whole trip. I'm sure your gas mileage sucked mightily going up 80...

 

Andy,

As others have stated, you are wasting gas. Since Electric miles are cheaper and cleaner than Gas miles, use the battery charge when you want, but you should Totally Discharge the battery before getting home or any other location that allows you to Recharge. If you get home with any battery left, you are using more Gas and getting lower MPG.

 

Andy,

You don't have to use all your battery right away.

Put the PIP in HV as much as you want, but get it back to EV and use up the battery before you get home.

 

the worst thing is when you are on an unknown route, you're near home, but you use up your ev a little too soon.

 

This is pretty much counter to what I have experienced. I get 1.5 to 2.1 miles of EV back at the end of my commute when going home. The car will automatically switch from HV mode back into EV mode at 1.5 miles. It is possible, with a big enough downhill, to almost fully recharge the battery just from regen. What you describes sound more like the 2010 test cars which didn't have the ability to recharge EV via regen.

 

That's not a problem.

When you use up the battery and it switches to HV, there is still battery available.
When in HV and you keep the energy bar to the left of the center line, it has the ICE off and is using battery.
The more battery you use, the less gas you waste.