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As a distance bike rider I know that if I pedal hard down a hill it helps me get up the next one.

As a prius driver would it pay off in MPG improvement if I accelerated (rather than maintain a constant speed) going down a hill in anticipation of the next one? Let's say I am going 55 MPH overall. How about going 58 downhill and slowing to 53 uphill (yes, I know it would irritate people in my lane, but think hypothetically).

It would seem that by simply coasting I would gain in battery charge coasting down and be able to use that energy at some point ahead. But if the gasoline engine is more effeciently used on its own (as opposed to charging with the associated losses in the transfer of power) is it better to accelerate moderately?

Does this make any sense? Better minds than mine are needed.
 

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Strategies

Hi,
I just my Prius 2 weeks ago and am trying to figure some strategies myself.

First, I noticed that when I go about 19 or 39 mph, I can get the car to kick in to electric motor only. Is it just me? I was able to stay at 39 for about a mile today (of course, it must be flat, or you'll need to give the car more power to maintain 39).

Also, I've noticed that occasionally the MFD sometimes shows no action between motor or engine and wheels when I'm going slowly. Why is this?

Thanks.
 

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Re: Strategies

drtravel47 said:
Hi,
I just my Prius 2 weeks ago and am trying to figure some strategies myself.

First, I noticed that when I go about 19 or 39 mph, I can get the car to kick in to electric motor only. Is it just me? I was able to stay at 39 for about a mile today (of course, it must be flat, or you'll need to give the car more power to maintain 39).

Also, I've noticed that occasionally the MFD sometimes shows no action between motor or engine and wheels when I'm going slowly. Why is this?

Thanks.
I noticed that as well. It seems at 39 mph-41 is as fast as i can go on a battery mode only. It needs the engine to help get there but ok. I tried the tapping the gas just a little and that seems to work because little boosts come from the battery.

This is only me, and I got mine today, and have only driven it 13 amazing miles.
 

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Normich said:
As a distance bike rider I know that if I pedal hard down a hill it helps me get up the next one.

As a prius driver would it pay off in MPG improvement if I accelerated (rather than maintain a constant speed) going down a hill in anticipation of the next one? Let's say I am going 55 MPH overall. How about going 58 downhill and slowing to 53 uphill (yes, I know it would irritate people in my lane, but think hypothetically).

It would seem that by simply coasting I would gain in battery charge coasting down and be able to use that energy at some point ahead. But if the gasoline engine is more effeciently used on its own (as opposed to charging with the associated losses in the transfer of power) is it better to accelerate moderately?


Does this make any sense? Better minds than mine are needed.
Some posters here feel that giving up a couple mph up the hills and regaining it on the down hill side will benefit your mph. I was convinced at first that worked, but after my first 10k, I now believe I can't beat the mileage the cruise control gets me and that holds right to the digit.
 

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Re: Strategies

drtravel47 said:
Also, I've noticed that occasionally the MFD sometimes shows no action between motor or engine and wheels when I'm going slowly. Why is this?

Thanks.
When you see no arrows, you are truely coasting, as if you put the car in neutral. You are not asking the car to power, so why waste it? It isn't like a conventional car where the engine HAS to be running.
 

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The Prius is not like a bicycle rider who benefits from smoothing out power demands, thus avoiding peak power output. Gasoline engines, including the one in the Prius, are not very efficient at low power output. Their best efficiency is usually obtained somewhere around 3/4 to 7/8 of maximum power output. So unlike the bicycle rider who benefits from adding power during the downhill stretch to reduce power needed on the uphill, the Prius will actually do better if you add power during uphill, then coast downhill. This causes the engine to shut off completely during the downhill stretch where it would otherwise be inefficient, and work harder during the uphill stretch, increasing its efficiency there.

Another problem with powering downhill is that you increase the maximum speed at the bottom of the hill. Since energy loss to wind resistance goes up as the square of speed, this causes further losses that could be avoided by coasting downhill and powering more during the slower uphill stretch.
 

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actually i am convinced that building momentum when coasting down a hill will benefit your mileage with a combination of not holding up traffic.

i also notice that cruise control will rev fairly high for small short hills where as i can control the speed manually much more gentler. problem is that cruise control cant see the hill ahead and goes on the speed of the vehicle only. on a hill that might need only a slight increase in speed to maintain velocity, the cruise control will rev high in an effort to maintain set speed. if the cruise control could program a 2 mph range similiar to a thermostat in a house, it would work much better on uneven terrain.

the cruise control is something in rely on all the time and when going down a hill i use it to bump up the speed as i use it to bump back down going up the other side.
 
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