fuel economy

Have you checked the archives here for info on this subject? Most new owners have questions about their mpg.

Basically, you'll find that your mpg will be less than optimal if you have a short commute, say, 10 minutes. A lot of short trips kills your mpg. Also, many have found that by increasing their tire pressure they can bring that number up. It is a trade-off in the comfort of the ride, however. Moderation is the key, I think.

Again, check the archives and see what other information you might find use ful. Just about every subject conceivable has been discussed.

Enjoy your car.

 

you have a mile and a half commute, you don't need a car you need a bike. I'm suprised it gets that good. I guess you didn't do your research on the car before you bought it or you would have known that until it's fully warmed up it's just like normal cars. Poor mileage untill warm. Fact of life in any car. I think Toyota will tell you the same thing. Read up on the EPA estimates and you will find out they don't take warmup into account in thier estimates.

 

It is not a good strategy to use the electric motor as much as possible. The better strategy is to use the electric motor as little as possible. On the energy screen, try accelerating with no energy coming from the battery. When you first start the car that will be very slow and will increase dramatically after about a minute or two.

The conversion of engine power, to electricity, to stored electricity, to motor, to the wheels is quite inefficient. There are rare occasions when the motor should be used to the exclusion of the engine. My high mileage numbers are the result of minimizing the use of the electric motor. Other factors are a friendly 30 mile commute, tint all the way around, mobil1 in the crankcase, few short trips, and minimal use of the brakes.

Recent tanks are 729 miles at 60.7 MPG, 768 at 61.8 MPG, and 263 at 63.1 so far on this tank.

 

<div class='quotetop'>QUOTE(Ray Moore\";p=\"99271)</div>

Ray,

Perhaps you could elaborate on electric motor usage being inefficient. My commute is roughly 25 miles each way with about half of it being highway and half being typical Washington DC stop-and-go.

My assumption is that on the highway portion of my commutes, I will always regenerate battery usage without penalty as the ICE will be spinning regardless of battery level or need to recharge.

I am averaging about 52 mpg-55 mpg per tankful but want more.

I have tried to coast by shifting into neutral, but find that is only practical in residential neighborhoods as I frequently travel a few 50 mph roads that have traffic lights around blind curves in addition to other conditions that make me hesitant to want to pop back into drive from neutral while traveling at speeds above 35 mph.

I have also tried to hit the "no arrow zone" but find that nearly impossible if traveling above 30 mph.

Overall, I am turning into a "blue hair" driver and loving that characterization that I once cursed. 8)

Herb

 

this month kentucky has had some hot weather and my morning trips (about 10 min.} went from 42 mpg to 38 mpg.turned the blower motor down to a lower speed and that helped somewhat.
the low 38 didnt come as a supprise,thanks to prius chat.this isnt to complain,we have to live with what we get.my tundra only got 13 in town and no telling what i got on my short trips.if all cars could display their mpg as does the prius there would be millions of people bitchin............
set back,drive and enjoy

 

Hi Herb-
Each time you convert energy, there is a loss. The most efficient means of propelling the Prius above say 10 mph is with the Ice. The waste incurred is in the form of heat. The inverter and the battery both have cooling systems to remove the waste heat.

The generator is maybe 90% efficient. It is often less efficient. The inverter has some loss in the inversion conversion process. The chemical storage into the battery is maybe 90% efficient. Depending on the state of charge and temperature, it can be less that that. The conversion back to electricity is not too bad but the motor is only about 90% efficient. When you compound those together, the system is not that great compared to just using the Ice directly.

There is no free electricity while driving. The generator puts a load on the system anytime the battery calls for charging. The best mileage occurs when you have six bars on the SOC display.

I can almost coast the last two miles to my house so when I got the car, I tried to use the motor to get me over the spots where I couldn't coast. I thought it would be good because the battery would charge up the next morning while the engine was warming up. This would usually result in an SOC of four bars. After trying it both ways many times, I have concluded that the overall mileage is always less when I use this strategy. I have a landmark that I use coming and going to compare the mileage. If I minimize the use of the battery, I can get back to the agerage I saw in the afternoon at this point by the time I reach it in the morning. If I run the battery down at the end of my trip home, I am not even close to the same average when I reach my landmark in the morning.

The only time it is wise to run the battery down is if you are approaching a long downhill where the charge from regen will exceed six bars, or if you can use an EV button to avoid a warmup cycle that is not utilized by a commute.

 

The reason people think it is wise to run on electric alone is because the media keeps repeating the myth that the electric motor is designed to propel the Prius at low speeds and the engine is for higher speeds. This is true if you define low speeds as less than 10 mph. Another myth is that the battery gets its charge from brake regeneration. Only a very small amount of the battery charge comes from regeneration. The public gets a very slanted view of the car.

The electric motor is there to supplement the takeoff power of the anemic 1.5 liter atkinson cycle engine. If you only had the weak engine, the mileage would be better and the performance would be totally unacceptable.

The public would know a lot more about the Prius if the press never reported on it. They may have never heard of the car but their fact ratio would be better at zero than it is with the current level of media misinformation.(disclaimer- the preceding paragraph is a slight exageration based in truth)

 

Doc, you hit it on the head there. Olathe Prius bought all the hype, didn't look into things themselves, and now wants the Gov't (i.e. the law) to make it all better.

Ignorance- The state of not knowing
Stupidity- The state of knowing and ignoring the knowledge

 

Take it easy guys. First Welcome to PriusChat Olathe.

Unfortunately, Olathe you asked this very popular question (only asked every other week, heck 2 other threads are still going). TBH, for only 1.5 mi I would bike or walk except if it is raining. I used to work about 1 mile and would only use the F250 for long trips or rainy days. Then before that I was 8 mi away and used to bike to work (Ft. Leonardwood, MO). I would keep a record of how much money I was saving by walking to keep me motivated.

When I got my car about 3 mo ago I had no clue about it other than what the dealer told me (hybrid with great gas mileage and EPA info on sticker). I did not find PriusOnline until a week after I got the car and even though I am an engineer I know very little about the working of the car (except the thermo/aerodynamic properties of it). Then finally found PriusChat.

I had always thought the elec motor was better but now that you mention it, it is inefficient (converting power there will alway be some loss). However, I have gotten better mileage if I only use elec for the last leg of the trip draining the battery to 2 bars. Regardless of battery level the car runs the ICE when I go home and might as well recharge the battery since the fastest I can go for the first 5 min is 25 mph due to on post speed limit. The trip to work is a little different since I live on a hill and can go faster.

As stated earlier, nothing you can do except move 30 miles away from work. So just sit back and enjoy life knowing your mileage on an ICE would probably be much lower.

 

if your normal commute is a mile and a half you should also do oil changes at 1500 mile intervals. The build up of moisture in the crankcase from that type of operation will be significant because the ICE never gets warm enough to evaporate the moisture. Even if you switch to synthetic, I'd still dump it under those circumstances.

 

good point. I think I read that very short commutes constitutes severe conditions and to change the oil at least at 3k mi for synthetic.

 

<div class='quotetop'>QUOTE(Ray Moore\";p=\"99271)</div>

Bah Humbug. If you wanted a underpowered economy car that does 0 to 60 in 30 seconds then you should have bought one.

The whole point of the battery and electric motor is to store energy when the engine is running efficiently and to use that energy to augment the ICE when the engine is not running efficiently.

When you avoid using the electric motor during acceleration, you are forcing the ICE to do all the work when it's operating least efficiently. It's reving at high RPMs but the car is not moving very far. Near the end of your acceleration, and while at cruising speed, the ICE is running more efficiently, and that's when it would charge the battery back up.

So, using the battery means you replace energy produced at low ICE efficiency with energy produced at high ICE efficiency. Sounds like a winner to me, even if there is a conversion loss.

For a 7 or so mile stretch of my commute, I use the electric motor almost exclusively to maintain speed. Most of it is relatively flat and it doesn't take much energy to stay at speed. With a couple of stop lights and a modest hill, my SOC never drops below 5 bars unless I've got the AC running on a really hot day.

 

rcroft- I invite you to check your 0-60 time in normal driving. Next time you start from a light and while accelerating normally to 60 mph, time yourself. Please post us with your results.

The point at which the computer decides to use energy from the battery or store it in the battery is the point at which the computer determines that the engine is running most efficiently. That point of no arrow operation is the most efficient use of the engine. Either side of that point the system is going to incur conversion losses through the battery.

It is a great system that helps to minimize engine inefficiency but it is even more efficient if you try to operate in the most efficient range of the engine without the conversion losses.

The difference is not huge but is probably what enabled me to get over 60 MPG on my last three tanks in mixed driving. Of course, it all has to be done within reason so as not to hinder the free flow of traffic or keep me from being on time for dinner.

By the way- are you angry?

 

I hear what you are saying Olathe Prius. While I appreciate what our fellow Prius owners are trying to tell you, I tend to agree with you. I live in the Washington, DC area and it is very hard to get the reported 60/51 mpg around here. When I bought the car I lived 30 miles from work and I got about 45-48 mpg on average. Now I live about 7 miles from work and I get around 38-40. Also, yes I have tried all the tips and suggestions in these posts. Nothing really seems to help. The bottom line here is, you really have to drive like a grandmother to get above 50!! I have not even been over 45 in the past month!
However, there is an exception to everything. Say for instance if you get caught in a major traffic jam (stop, go, stop, go, stop, go) you will definitely see a major jump, but since I do not travel the interstate any longer I never do see that jump. I am stuck usually under 40mpg for 6 days out of the week.
Don't get me wrong, this car is awesome and I love it, it is great for the environment etc. I just think that I (we) should have researched it more before paying full price for it. My Beetle was getting mid to high 30's and my payment was cheaper It really does seem like this problem does include a little false advertising about the mpg. Not everyone can drive 30mph to work and back and not get blown off the road by angry drivers. They should include that on the window sticker.

 

<div class='quotetop'>QUOTE(Ray Moore\";p=\"99366)</div>

I'm not angry. However, I don't think you need to tell a new owner that the only way to get decent gas milage is to accelerate like a 100 year old woman.

I accelerate at a moderately brisk speed. I don't offhand know what my 0 to 60 would be, but my 0 to 40 is about 8 seconds. I get from 0 to 30 in about half that time and then I ease off the gas pedal as I approach my cruising speed.

I get about 55-56 mpg on my car. I would get higher, but I make four 2-mile or so trips during the day that really kills my milage.

My commute to work is 20 miles and I average 40 mph. It is mostly flat, but there are two sizable hills (actually dips) along the way, and there are 11 stop lights (12 if I get stuck at the commuter train crossing). It is slightly more down hill on the way to work than on the way home.

It takes me a little over 30 minutes, so I have a full history window on the consumption screen at the end of my commute. The first bar usually shows about 35 mpg. The second bar typically shows about 50 mpg. The remaining four bars depends on whether I am going to work or coming home.

On the way to work, the last four bars are usually between 65 and 75, although I've seen on occasion a few bars showing between 90 and 99. This happens during one of the stretches were I can usually use only the electric motor to maintain speed. And when it does happen, I don't see a complimentary drop in the next bar, as your explanation would seem to predict. Instead the next bar is again in the 65-75 range.

On the way home, my numbers are a little lower, because it's slightly more uphill than the way to work. My last four bars will typically show between the high 60 and 65.

I haven't isolated just my commute on the consumption screen, so I don't know exactly what I average during my actual commute, but I suspect it is 59 or 60 mpg. My actual mph is around 55 mpg due to the four short trips I make during the day.

I accelerate at a reasonable speed from a stop, or if I'm making large (10+ mph) speed adjusments. I glide when I can , and use electric only when gliding just isn't enough. I try to stay under 42 mph where I can because I can maintain speed with the electric at those speeds. When accelerating at cruising speed, such as going from 41 to 45, I do accelerate very slowly and try to keep the mpg as high as I can while I do it. I will usually tolerate a 5 mph drop in speed when going up hills to keep the mpg as high as possible.

My SOC never drops below 5 bars, unless the AC is running on a 90+ degree day, at which point it will drop to 4, or even 3 if I spend a lot of time at a light. This usually happens at the beginning of my commute home, when I'm not getting good gas milage anyhow. Once I get about 10 minutes into my commute, the cabin has cooled off and the Auto-AC has it's fan set at either the low fan speed or the next one or two up. At this point, I might be getting consumption bars closer to 60 on my commute home.

So, by accelerating at a fairly normal rate, allowing the electric motor to be used when it wants to, and by using a light touch on the gas pedal at cruising speed, I get mpg in the ball park of what you get.

By the way, geography has a lot to do with it. I used to travel a different route to and from work, because on the route I use now, I would get stuck for 10+ minutes waiting to turn left at a traffic light. However, they've since fixed the intersection, so I switched.

The previous route I used was more rural, had only 4 trafic lights, was a little longer in distance, but I could go 55+ on it. The downside was that it had four really big and really steep hills. When using that route, I averaged between 44 and 46 mpg. The hills robbed me of a lot of my mpg and the cruising speed was too fast to utilize the electric motor to maintain speed.