Much better mileage on the freeway than city....what am I doing wrong

"City" comes in 2 flavors... the heavy congestion, takes forever to get a few blocks... and suburb driving. The latter is dramatically more efficient and takes advantage of the hybrid system more so than "freeway".

 

There's a common idea that city driving is supposed to be the only place a Prius shines, because that's where it can alternate between sending power to the wheels, regenerating from the wheels, sending back to the wheels, etc., and that's the special trick everybody knows a hybrid can do and other cars can't.

As it turns out, that's not as efficient as the popular belief would have it, because there are conversion losses in both directions shoving charge into the battery and getting it back out. Meanwhile, a nice highway cruise is just a steady flow of power from the gasoline engine and out to the wheels.

The hybrid design, with some extra grunt from the battery when you want to accelerate, also allowed them to build a car with a right-sized, highly efficient, Atkinson-cycle engine. It can't, on its own, produce the kind of peak horsepower you normally want for accelerating, but you've got the battery to help with that, and for cruising down the highway, the engine is super efficient. That's the part of the hybrid story that often gets left out in the telling.

 

It’s a misrepresentation on that claim by Toyota on average mpg, like John1701a said city traffic come in two flavor it’s 100% true, When I first got my 06 Prius I researched a bit concerned about this claim I was getting about 44 mpg hway and about 33 mpg in the city and even with the use of the ac or heater can even go into the 20’s mpg so you most be driving in a congested city that all it’s, now that I move to a new city where the only things that stop me are the traffic signals I make about the same in hway but my city mpg was 33 now easy 48-50 mpg, so if the car is in good shape I will blame the low mpg to the traffic or to much stop and go in you city and not worry about the car, if this is you case you may want to get a regular ICE car since you really not taking full advantage of the hybrid system and will no worth the risk of waiting for a big expensive repair arrive in the future, if traffic or excessive stop and go it’s not you problem then you need to check what is wrong with you car, excessive stop and go it’s when the car doesn’t get a chance to regenerate enough power to recharge the battery pack.

 

Even though stop-and-go isn't where the car gets the best mileage, it still gets darned respectable mileage, and during the stopped parts I'm not sitting there idling an engine like the surrounding cars.

Other cars can have expensive repairs too. The overall studies on total-cost-of-ownership that I've seen don't offer a whole lot of room for beating a Prius.

 

The reason why city MPG it’s higher than hway it’s because the car in the city regenerate energy that other wise would be wasted so that energy go to the hybrid battery pack to help the ice to archive a better mpg and because in hway you just cruising to a speed not slowing down you hardly generate enough energy unless you happen to go down a hill this is the reason why city mpg is more than hway under the expected circumstances by the Toyota MPG, now when you driving way to slow like staying under 25 mph the car hardly regenerate enough power and if you no regenerate power you driving mostly on you ice and hybrid system only pauses the ice when slowing down or at full stops but can’t assist the ice much with drained hybrid battery pack, about the expenses you right but Hybrids have more things that can go bad resulting in more expenses.

 

#6 pretty much epitomizes the usual story about hybrid efficiency that assumes it has mostly to do with regen, when in fact regen has built-in conversion losses in both directions, and the ability to right-size the engine and use the Atkinson cycle (lower peak output but better crtuising efficiency) gives a clear highway advantage too.

As for the cost of ownership, it's easy to get lost in offhand statements like "have more things that can go bad" (don't forget the hybrid drivetrain has also eliminated a lot of things that can go bad), but ultimately the best information is going to come from studying the total expenses over a large number of cars and a period of years. Those kinds of studies do get made, and they generally don't show very many competitors ahead of the Prius for low TCO.

 

#7 I respect you opinion but my is the more juicy you hybrid pack can get from normal driving the more mpg you car will get.

 

You can think of it this way.

There isn't any energy in the hybrid battery that didn't get there by burning gasoline. (I'm obviously excluding the PiP and the Prime; they have another way for energy to get into the battery.)

The car can charge the battery sitting still, just by running the engine, using gasoline.

The car can charge the battery while you're driving if needed, just by running the engine a little harder than needed to maintain the road speed.

The car can charge the battery when you brake, by regen from your forward momentum. You got the forward momentum by burning gasoline.

The car can charge the battery when you roll downhill, by regen from your gravitational potential, which came from burning gasoline going uphill.

If you bought the car from a dealer at the top of a big hill, your first downhill was free (to you), and since then, there has never been any energy in your hybrid pack that didn't get there by burning gasoline.

But every time energy is pushed into the battery, some of it is wasted as heat (which is why the battery needs a cooling fan). So the energy that ended up in the battery is only some of what you had.

That's not all. When the car draws that energy back out of the battery, some of that is again wasted as heat, so you only get back some of some of what you had.

If you have the choice between driving in a way that just keeps energy flowing from your gas-burner out to the wheels in the amount you need, or driving in a way that stuffs energy from the gas-burner into the battery and later gets only some of some of it back out to use at the wheels, other things equal, the former approach will improve your mpg.

 

I would say Gen 2 Prius provides best MPG on long drives at 50-55 MPH. Often city drives tend to be shorter where ICE gets used more in warming up the engine. You would notice 25 MPG for first 5 minutes of drive even at city speeds. Highway drives on the other hand tend to be longer where overhead of heating engine is absorbed. But then we get higher speeds and associated Drag resistance to go with it. Speeds of around 50-55 is the sweet spot.

I fully agree that Prius is a gas engine car. Any regen is just to recover what would otherwise be lost as heat. Best is neither ICE/ or battery getting used as in Glide mode. But otherwise just ICE being used and no battery is the second best option. The role of battery is to provide additional boost for higher power requirements and regeneration to recover major part of the energy which would be otherwise be lost as heat. But then it does have cost of losses during every conversion. Kinetic to electric to chemical energy and also the other way.

 

My 08 gets 42 no difference in city or hwy.

 

It look like it you don’t understand, so many Prius drivers are hated on roadways because they are pulsing gliding coasting doing as much as they can to regenerate the more they can and use the less possible gas they can also, sure you use gas to be able to regenerate but It’s no a extra gas it’s only the gas you use to go from point A to point B so you don’t understand you didn’t pay for gas to regenerate, you pay for gas to go to you destination only and have a free regeneration because unless you want to crash you need to slow down and stop anyway so that how you regenerate and you don’t pay for that.

 

Pulse and glide does help with mpg, just not exactly for the reasons you think it does.

 

Pulse and glide help to use less gas that the reason I think, do I wrong, don’t think so.

 

This is an artifact of the very artificial EPA MPG scoring system, which bases its City and Highway MPG scores on artificial test cycles that match almost no one's actual driving patterns. And the final scores are weighted by different empirical fudge factors that attempt to translate the well-defined dynamometer tests results to something close to the ill-defined results of typical American drivers. And those are ever-changing targets as drivers continually make use of their increasing horsepower to drive more aggressively on roads with higher speed limits, but also with more congestion.

This artificial and empirical scale was also built around traditional non-hybrids. While it has since been adjusted to be more realistic on hybrids too, it isn't perfect at that. Or at anything.

Remember the disclaimer, "Your Mileage May Vary." Your City and Highway results likely will vary differently. Some people's driving conditions will get better highway mileage, while others with different conditions will get better city mileage. Almost nobody fits the official test definitions.

Don't worry about it. Don't overthink it. It doesn't mean that much.

 

The majority of the problem is with the Goverment's method for testing fuel economy. The test sequence is artificial and based on average driving patterns of 50 years ago and have not been changed - they have little or no relevance to the real world of today. In fact they even say that the mileage posted for each model are really only valid to compare between vehicles during the purchase process. You should not expect the same results in actual use. I have noticed the same thing in my 2004 Prius and our new 2018 RAV4. Fuel mileage in long distance highway driving is considerably better than "city" driving. For example, in a typical large metropolitan area, a commuter may spend as much time at a standstill as they spend moving at the speed limit. Even when stopped the engine periodically has to run to charge the battery - to keep the air conditioning, radio, heat, lights and other accessories running. Fuel is still consumed but you are not going anywhere. The numbers you calculate are for your vehicle, for the way you drive it. They are a guide, but not directly comparable to numbers other people get.

-Graeme-
2004 Prius with >190,000 miles.
Sent ?.

 

It can be helpful to consider why the technique is called "pulse and glide" and not, say, "pulse and regen."

In fact, it is easy to end up doing "pulse and regen" by trying to "pulse and glide" with too little finesse on the go pedal.

And ending up doing "pulse and regen" will worsen your mpg.

 

Man am sorry I can’t help everyone here not my fault you can’t get as many miles as others that understand how to make the car beat the estimate mpg expected from the manufacturer, you first have to understand how to get free reg before that can happen, because pulse glade and coasting are only part of the equation, you free to believe whatever you want as I do too, enjoy you Prius brother, bye.

 

@Frank1234, Chap never said he couldn't get as many miles as others, nor did he dispute that you do not get good millage either.

He is simply saying the logic of the argument you use to explain why you do ok or even beat the EPA, is completely wrong.

In essence, what he is saying is, all energy ultimately comes from burning gas and secondly, there is no such thing as a free lunch.

Maybe reread the posts a few times and try and understand what is being said, rather than being argumentive.

 

I may have explain my point Incorrectly but sure the are not free lunches,,,, but there are lunches that I didn’t pay so many times and sure they was no free,,for my boss,,but since he payed it was free for me, if we want to go so technically you right but I still didn’t put out money for my lunch so was free for me.