60 to 70mpg

Hi Andy,

North or South Virginia St? Could you give some coordinates or cross streets? This would help identify the route.

The usual cause is an altitude change and using Google Earth makes it possible to read out the altitude over the route.

Bob Wilson

 

Short answer: You might have been going downhill on the second bar, so you barely used any gas. You may have encountered additional high-acceleration areas in the 3rd bar, you are forced to brake more, or you have been sitting at a red light.

 

I was going to post a similar topic actually. I also have observed this to be true.

My feeling is that in the second mpg segment you get great milage b/c you use a lot of the battery. When the third segment begins your batt is really low and thus has to recharge with the gas resulting in more gas being used in the third segment.

I think this might be a flaw in the system if im right

 

Ah, you beat me to it. I was going to say much the same thing. Although I wouldn't call it a flaw. The Prius is trying to predict how best to use its energy resources to maximize its efficiency in the near term.

After warm-up (usually confined to the first period unless you're in a cold climate), you probably had a relative surplus of battery power available -- the engine ran for heat and not just power, so the battery captured some of that extra energy. Result: depressed mileage. That surplus energy was used primarily during the second period. Result: inflated mileage. You experienced normal operation thereafter.

The idea is to strive for a good overall average mileage. The bars themselves don't tell you the whole story.

- Justifyd

 

well there are times when I would consider it a flaw, such as being stuck in traffic for more then 5 minutes.

Your mpg for the first bit is awesome. However afterwards theres nothing to charge the battery up again in slow moving traffic.

I dont know how the car would know how long your going to be in traffic but i guess a little less of a battery discharge at low speeds would be appreciable.

 

That, my friends, is where the hypermiling skill "battery management" comes into play. Shifting into neutral to prevent amp drainage by turning off the MG passive drain of about 3-4 amps/second while under 40 mph, using the parking brake instead of the brake pedal to save another .2 amps/second and reduce a bit of drain at a stop.

Warp neutral instead of warp stealth to lower that battery-draining ~15amp draw to a .8 amp draw, only cost here is your using gas unless you bump into neutral before you cross the 40-41mph mandatory ice on point.

Neutral-stealth-glide to avoid accidentally feathering too much and pulling amps out of the battery.

Also headlights off, as they drain .8 amps or so, fans off = another 3amps saved.

 

The Prius doesn't really know what your future needs are -- that's my point. It simply calculates what it thinks is the most efficient way to meet current demands and some expected-in-the-immediate-future conditions (such as "traction battery is low and engine temps are down [lengthy electric-only run], so be ready to engage engine for any level of acceleration"). Naturally, it would opt to use battery power when readily available and sufficient to meet current demands.

I think you mean amps per hour (Ah), not amps per second. I've read estimates that the regenerative system peaks at around 100Ah when fully engaged, which would amount to 1.67A/minute or 0.028A/second. I believe the coasting regenerative rate is around 10% of that.

I definitely have reservations about using the parking brake as the primary means of non-regenerative deceleration. Certainly Toyota didn't design it to serve that purpose, and one can readily identify a series of safety hazards associated with that approach.

As for headlights and climate control, always utilize them whenever safety factors warrant their use. Efficiency gains from their non-use are at best of very limited significance.

Must be nice living in an area where hypermiling is a viable option! It's certainly out the question for me in my area...

- Justifyd

 

I ment using the parking brake at a stop (red light), combined with neutral. The parking brake makes the prius start beeping at ya if you use it while traveling faster then 3 mph or so.
Noticed a decrease as opposed to using the brake pedal OR the park button.

I would never condone a non-regenerative braking method over the regenerative method. The parking brake leech-reduction is just for speeds where regenerative brakes wouldn't have been used in the first place.

Oh, and I do my hypermiling during rushhour traffic on interstate 66, where people can't really complain that I'm driving "slow".
I do have an alternative route, but its more dangerous as well as less advantageous due to hilly terrain (where people expect you to drive the same speed going up and going down, sucks when people push the brakes while going down right before another hill) and stoplights placed at the bottom of hills.