fuel economy

rcroft-
Can you show me where I said that the only way to get good mileage was to accelerate like a 100 year old woman? I would never disparage the elderly. I hope to be elderly someday.

I don't hold up traffic when I drive. I drive the speed limit in the right lane or just over to pass in the left lane. Over the past 15 months, I've learned a few things about how this car works by making detailed observations and keeping notes. I don't guess about this stuff. I can tell you how much fuel I use and what my mileage is for each leg of the tank I'm on and I can tell you what the rate of acceleration is most efficient in the Prius.

I can hopefully share that information without insulting you in the process. Please refrain from paraphrasing my posts as the words I use are carefully selected and the translations that you have made are not accurate.

 

<div class='quotetop'>QUOTE(efusco\";p=\"99398)</div>

No, it was what we were talking about.

I responded to the following quote by Ray More:

He told the new owner to avoid using the electric motor as much as possible and to try to accelerate with no energy coming from the battery.

That quite frankly is silly. While I agree to light acceleration to make speed adjustments at cruising speed, such as accelerating from 45 mph to 50 mph, trying to go from stopped to 40 without using the battery is wasteful.

You say that the ECU attempts to keep the ICE at 4-5K rpm range. I bow to your knowledge.

Now I think you would agree that having the ICE at 4-5K rpms while going 10 mph is not as good as having it at 4-5k rpms while going 30mph. Right?

So, I think you would also agree that it is a good thing to allow the electric motor to increase your acceleration and therefore reducing the amount of time that you are going slowly with the ICE at 4-5k rpms. Right?

This is contrary to what Ray Moore said, and that is what I was contesting.

And as far as trying to keep it in electric mode, I do that on long flat stretch of my commute where I travel between 38 and 41 mph. I'm doing pure electric probably about 70%-80% of that 5-7 mile leg. At that speed on a flat road, gliding (no arrows on energy screen) is just not quite enough to keep speed, but the electric motor does it quite handily. It takes very little energy to maintain that speed on a flat road, and the SOC drops at most one bar. And a couple of trafic lights or a down hill stretch, pops it right back up.

I use the ICE plus the electric motor while accelerating, and where I can, I use the electric motor to maintain speed. It works great for me.

 

My very best mileage is obtained from maximizing my battery use mostly, compared to just driving it. I'm starting to wonder why different people are getting such different results. Here I am not talking about acceleration mainly, as I have tried that various ways and seen little net effect. But I see big benefits the more I can run on battery overall.

I can think of a couple of possible reasons people are getting different results:

1 I get the impression different Prius have code that is optimized differently and this could explain some of this.

2 Another effect is terrain. Where I am there is little flat highway, and so I can drive on battery for 2 miles at a time frequently with little net battery discharge. The down hills are not enough to just coast, but very little extra power is required. Then I go up a hill and the battery recharges while I get 20 to 30 mpg. The situation might be quite different on a flat level highway.

 

<div class='quotetop'>QUOTE(rcroft\";p=\"99407)</div>

Thanks for this info. Though I've only had the Prius for 128 days - but who's counting? - it seems increasingly clear that the single greatest factor in mpg is simply the conditions in which it's driven. You've provided solid additional evidence - same driver, same ultimate destination, but different topography can lead to a major difference in mpg.

The good news for people getting lower-than-average mileage is that they were almost surely getting similarly lower-than-average mileage in their previous car. It may simply have been disguised because 16 mpg instead of 20 seems pretty close, while 44 mpg instead of 55 seems like a rip-off - even though in each case it's 80 percent of expected mileage.

(Sorry, Gaithersburgprius - the crystal ball has no words of wisdom for your plight. )

 

I did a test with my car by driving with a friend where we both drove on the same road at the same cruising speed. He got 5 mpg less than I did by just driving like the other drivers. He like them never cared about economy and drove accordingly.

Besides the obvious that would hurt mileage in any car, he never mastered stopping at a light with the creep turned off, which is kind of a Prius only issue. Also by braking hard he guaranteed 0 benefit from the regen.

 

Olathe, did you forget to take your meds?

 

All,

Thanks for all the posts...being able to read different opinions, and different views will really help me out when I pick mine up next week. I'm glad I read this thread, as I wouldn't have known the break in period would be more than 500-600 miles, and apparently it's much more than I expected it would be. So that will help. Another question I do have is, and this may be a dumb question, but does the Prius ECU learn the individual driver's habits? Just popped in my head. I know a lot of vehicles ECU's will eventually adapt to a driver's habits, but the Prius is far from ordinary, so you never know. Perhaps if it does develop learning capability for each driver, could the inconsistency of that particular driver be what causes poor MPG as well?

Thanks

Dave.

 

ok my last piece of advise to you, take your car back to your dealer and tell him to reflash the Hybrid Vehicle computer with the latest code. If that doesn't work, well your stuck with your current mileage.

 

this flash was part of the US service bulletin SSC-40-D and was to address the car not being OBD11 compliant but has made a difference in the mileage that people get. There are several flash updates so get the tech to look for the latest. A couple of months ago I posted an update on the wifes's 2k4 getting much better mileage after the dealer couldn't get the car to flash and they replace the HV computer and it's gone up almost 5 miles to the gallon. So it's worth a try.

 

read thru this thread
http://priuschat.com/forums/good-news-vt8513.html

 

I'm with Evan on this one also. This morning I did a 1.9Km drive and averaged 8.3 liter per hundred Km. this works out to 28.33 USG in my Classic. The wifes 2k4 on the same route this morning averaged 7.9 liter per hundred Km. 29.77 USG. Now I know this isn't his route but this is basically flat with 2 small hills. Temp was 17C about 64F So I think your in the ball park. Today my car just went into S4 at the mile and a half, 71C at 1.9K.