Reduction in fuel economy, to reduce gas consumption

On the normal hybrids, I see folks plotting longer routes to get higher MPGs by avoiding some obstacle. Many of these folks are using more gas, than if they took the shorter route and 'suffered' lower MPGs. High MPGs is not my goal, less gasoline consumption is my goal.

This trap can effect the PHV as well, "to avoid turning the engine on, I will drive this 3 mile longer route" may result in greater energy use even if it makes a prettier graph.

 

My PIP's electric miles actually cost me more than using gas, due to our high energy rates in Westchester NY and lack of smart-grid metering. And this is true even considering that I have solar PV, since my PV doesn't fully cover my home usage, though it exceeds my PIP demands - that is, if I didn't charge my PIP, my solar would offset more fully the expensive power my home uses. I do get my utility power from renewable sources, but I hope ConEd "smartens" our grid up and I can get cheaper kWh at night.

 

i'm thinking plug in hybrid that decides for itself when to use each mode or blended, instead of giving operator the choice. more like regular hybrid.

 

We're currently filling up about once a month, this is a regular, non plug-in Prius. And typically there's at least a 1/4 tank left, putting in between 25 and 30 liters (~7 US gallons) per fill up. A fair bit of the use is short trips, so mpg suffers a bit. But we're ultimately using less gas.

 

Excellent points!
Although, the quest for mpg (or MPGe) sometimes even further increases efficiency.

Three examples...

When I drove my Prius, and later my small EV, I would often take a slower, city street route which was shorter.
The efficiency of both vehicles was higher on that route and the distance was shorter. So efficiency went up and fuel use went down.

I used to drive longer distances to avoid rush hour traffic jams. With the Prius they weren't so bad, and with my EV they are not bad at all. As a result I no longer drive greater distances to avoid heavy traffic.

 

In my experience, this is basically how the PIP operates in HV mode when there's an EV charge. Of course nobody wants to stay in HV all the time, because it makes your HV/EV ratio screen look pretty sad, and since your ICE will tend to run more during times when it's really needed (going uphill) your HV MPG will look bad.

Regardless, it is my belief that (especially for trips where you know you'll consume all of your EV charge) this is the way to go. If you look at total gas/power consumed for distance traveled, this is how I've gotten the best results. It's probably an example of how the information given by the car can lead to behaviors that aren't truly the most efficient. (not getting the whole picture from the displays)

 

correct me if i'm wrong, but when i charge up, put it in hv and go, it uses 3 or 4 miles, then preserves the balance of 11 or 12 ev miles on the estimate.

 

I'm really confused about what the OP is asking/saying.
I drive using hypeermiling techniques. I charge whenever I can and choose routes for economy. My electric miles use $4.75/gal fuel ($0.12/KWH), my gas miles use $3.5 fuel. My MPGE on electricity is about 100. My MPG on gas is about 60. My cost/ mile on electricity is about 22% less than gas. my average speed on electricity is significantly lower than on gas, I suspect if I traveled the same speed the costs would be even closer.

 

Certainly this could be the case. However, at least for the PiP, preventing a cold engine from coming on for a brief time may be the most efficient use of all "fuels" involved even if the vehicle is driven for a slightly longer route. In such a case, staying in EV might avoid a startup penalty where ICE mpg would be poor. Also, avoiding once or twice daily quick on/off cycles of the ICE is probably better for the life of the engine.

For example, consider a route in a PiP on a cold day where taking the freeway during a segment yields the shortest trip for a commuter. But doing so requires the ICE to fire up for a mile or two because of the high speeds. Perhaps an alternate route takes 3 miles longer but involves low speed side streets that do not require the ICE to come on. The latter route may be the most efficient use of fuels and use the least total energy. In such a case, there would be no ICE warmup penalty and EV efficiency would be better given speeds closer to the 15-20 mph EV efficiency sweet spot.

 

this is way too complicated to try and make a decision. i think 'just drive it' fits the bill here.

 

Me too. While it's fun to fiddle around to get the best numbers sometimes, but it stops being fun when you have to make yourself jump through too many hoops.

I suppose a 500 cc engine would still get me around and save a ton of fuel, but I bought my Prius as the best compromise of all the features I wanted.

 

Like not plugging in to save on battery life?

 

Yeah, but that wouldn't even work. The battery would go dead on it's own, thus shortening it's life.

I could shut my power off in the house at night and use thicker blankets.

 

I recommend reading this post: Prius C Saves Gas -- BOGUS | PriusChat