Prius can get higher city mpg than highway mpg

So the Prius gets roughly 5 miles more per gallon when driving in the city then on the highway. All the explanations I see says that this because of regenerative braking.

I understand that energy can be saved from regenerative braking but obviously its not 100% efficient... or >100% efficient which it would have to be in order to achieve more mpg city, right?Looking at this from an energy standpoint and I can't understand how stopping and accelerating, even with regenerative braking, is more efficient than maintaining speed.

Someone help me out here.

fueleconomy.gov/feg/bymodel/2017_Toyota_Prius.shtml

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cuz the car cant use electirc battey motor if it going too fast.

If u brakin around town n shit it means hybrid HYBRID Mode so like its a mix of battery motor and gasoline

doin 60? ur whip aint usin no battery son. petrolium fuckin only

It needs petrol to maintain highway speeds.
In city it uses electricity

so its just misleading because it doesn't include battery usage in the mpg? I also thought the battery was only charged by gas engine / braking or do you have to plug in a hybrid to use the battery?

fueleconomy.gov/feg/fe_test_schedules.shtml

Highway test is 50-60MPH
City is mostly 30.
Wind resistance is pretty negligible at 30. Not so at 60. The Prius probably gets 80MPG at 30.

>misleading
>battery usage in MILES PER GALLON

How many gallons of batteries did you use today, user?

If I recall correctly you don't plug in a prius, the battery is charged with braking/gas as I mentioned above. Therefore all battery power is created from energy in gas.

>What are hills

>that explains it. the car is just a lot less efficient at higher speeds.

lmao. how do you think the car gets up the hill?

Solar roof and there is a plug in Prius as well. Batteries hold.charge generated from previous journeys as well. If they don't have electricity they use gas

Engines are more efficient at generating electricity than they are at driving a car.
All fuel consumption is measured, whether that fuel consumption is purely charging the battery, partially charging the battery or not charging it at all.

On battery power, of course

>Engines are more efficient at generating electricity than they are at driving a car.

>converting torque to electricity and then back to torque is more efficient

bruh that would mean >100% efficiency

>All fuel consumption is measured, whether that fuel consumption is purely charging the battery, partially charging the battery or not charging it at all.

this makes sense, still misleading if they don't measure the battery level before and after the mpg test and account for the difference

Engines are most efficient at only one point. Does a car drive at only one speed?

It means that electric engines are much more efficient at producing torque to move a car than the drivetrain being used to mechanically transfer all that torque.
So yes, it is usually more efficient to run combustion engine to produce electricity, then use electricity to power electric motor to move the car than it is to just use the combustion engine to power the torque converter, drivetrain, mechanical linkage, etc, etc to drive the car.

Oh gee, you better report your findings to railroad companies so they stop wasting money on diesel-electric locomotives

So the electric motor is set up with a mechanical advantage that the engine doesn't have? I understand that the engine creates energy most efficiently at a certain point, but that energy still has to be converted back to torque at varying (less-efficient) ratios depending on the speed of the car.

Yes, it takes more energy to stop and start vs. maintaining a consistent speed. However:
1. Energy lost to air resistance and rolling resistance becomes significant at highway speeds.
2. As previously stated, internal combustion engines have a small range in their power curve where they are optimally efficient. When charging a battery, they can operate in this range, whereas directly driving the wheels, they must operate over a much wider (and therefore less efficient) range.

Electric motors allow the gas engine to be "right sized." Instead of needing an 8L 600HP V10 to get up to highway speeds, a 60HP engine is fine. They also don't have the transmission losses.

I'm not sure i follow you. The inherent advantage that using an electric drive motor has is that of linking the power to the work.

A traditional gas car gets its power at the engines and then delivers it to the wheels through all sorts of mechanical fuckery: converter, clutch, axles, and a half-dozen joints in between. Every mechanical linkage has to overcome friction and creates heat, noise and vibration, which eats up your available power. The farther your drivetrain has to go, the more power you lose.

A combustion -> electric drive circumvents most of those problems. Power is still created at the engine, transferred (nearly) losslessly to the electric motors which are situated right at the work to be done, moving the wheel. You don't have a ton of parasitic losses along the way.

1. In the city the prius uses regenerative braking with electric motors and batteries to lessen the work done by it's internal combustion engine
2. On highways, this becomes useless as high speeds are usually maintained for consistent and long periods of time.
3. Even though it's electric drivetrain is now useless, it still must carry the weight around, decreasing efficiency.

TL;DR: Shit's heavy and useless on a freeway.

Which comes from?

Charging the battery when you braked going down a different hill. Do I really have to explain everything to you?

Trains use diesel-electric primarily because a transmission for a train would be impossible or retarded.

And how did you get up that first hill?

You're very clever, user, but it's hills all the way down.

from electrical energy in the battery dum dum

Which came from?