high mph then glide

[Hockey4mnhs]

Originally Posted by psyshack

On needs to do some research concerning there AT cars. Sure looking into the manual is a good start. Boards like this one geared twords the car in question and word of mouth will get you the info you really need.

To the member that posted concerning a tarus at. They where known to be bad transmissions. Ford refused for years to drill a 1/8th hole in a casting. It caused a high pressure issue in the tranny and made them shoot craps. After Mazda used the unit in one of there cars with the mod made and no problems. Ford woke up and cured the issue.

To another user here coasting a Mopar mini van. I wouldn't do it. later models have shown they like to chew up transmissions. Its there known weak spot.

Another car I wouldn't EOC in is any late model V6 anything Honda. Be it Accord, Ody, Pilot, TL or Ridgeline. While Honda I4, At's seem to be near bullet proof.

And for goodness sakes AT drives. Keep the fluid changed out in them. And be sure to do the filter if it has one. Yes some AT's dont have a filter. Some just have a screen buried deep in the unit. That is not serviceable.

A little secondary reseach can go a long way.

psy

So your saying my car is ok? its a I4 93 accord.

[jandree22]

Originally Posted by veloman

And how practical is it anyway? Are you going to yo-yo down the road in traffic? Dip to 45mph on the interstate and get run over? lol

This is a valid concern that I have too... people seem to get pissed enough at me for doing the limit to 5 over on the Interstates steadily. Don't you guys get flashed with highbeams or horns honkin, especially when there's no passing lane

[popimp]

The speed limit is the upper limit not the lower. Unless there's a minumum speed limit then you have every legal right to go under the speed limit. People don't care because gas is still too cheap. Give it some time and they'll figure it out.

[Hockey4mnhs]

Originally Posted by jandree22

This is a valid concern that I have too... people seem to get pissed enough at me for doing the limit to 5 over on the Interstates steadily. Don't you guys get flashed with highbeams or horns honkin, especially when there's no passing lane

When i do high speed p&g i stay with or ahead of trafic my average speed is about the same.

[1993CivicVX]

I find it interesting there is no talk about Hybrids on this website. I have to mention this tho from driving my mom's '07 prius: In the '04 and newer Priuses, pulse and glide is easy between 29 and and 41mph. By slightly depressing the gas pedal you can coast--effectively be in neutral while in drive. But it's nearly impossible to coast by using the gas pedal at speeds higher than 41mph. For some reason Toyota made it so you can't easily find neutral by slightly depressing the gas pedal--you'll either be regenerating the battery or be accelerating. Is it bad or somehow disadvantageous to put the car in neutral when coasting at speeds higher than 41mph? And then putting it back in drive BEFORE you need to brake? It seems to me this would be more efficient than leaving it in drive and either be slowing down by the automatic brake regeneration that the Prius does when coasting in drive or be slightly accelerating with the electric motor. Anyone know what I'm talking about? Anyone know if it's for some reason not more efficient to put it in neutral at speeds higher than 41mph?

[1993CivicVX]

Originally Posted by cfg83

veloman -



I don't think you can compare road cycling to P&G. For MPG competition, P&G is a proven technique. There is no debate on the subject.

I think that steady state mostly holds true for speeds at or below 35 MPH, where the car doesn't have to fight aerodynamic friction.

What are the racing techniques in those super-aero enclosed recumbent bikes?

CarloSW2

First, let me address why it works. The difference between road cycling and an Internal Combustion Engine is the fact that they are totally different forms of producing energy. One is producing energy through blood and muscles, the other through steel and fire. Furthermore a cyclist can't turn off his engine the way a car can. Even when he's gliding, he is still using energy because he or she is human--you're always using energy. When you glide in a car and turn the engine off, you're using no energy. It also prolly has to do with a mass to speed ratio. cars are much more massive than people. And P&G seems to be more effective at lower speeds than higher speeds. Maybe P&G on a bike at an average speed of 13mph is easier by pulse and glide than it is by maintaining 13mph at an even pace. At those lower speeds, your glide is going to be much longer (say you glide to 9mph and then pedal to 18 to glide back down to 9 and average 13mph by that method. Imagine trying to do P&G in Nascar at 190mph. Pulse to 190mph (would take about 20 seconds from 160mph) and then killing the engine to coast to 160mph from 190mph in six seconds and then spend 20 seconds pulsing again. Abusrd. (correct me if I'm wrong, I've never tested it but seems abusrd to me) There's so much wind resistance and drag at that speed that your glide is going to be super short! Likewise on a bike it wouldn't seem like an economical way to ride at racing speeds of 30mph. In a car, 30mph is an ideal speed to do P&G.

The racing techniques of cyclists is to draft. In this sense pro-cyclists actually *are* doing pulse and glide. Because you have a leader (the equivalent of the pulse) who is pulling the pack that is drafting (the gliders.) Hills as well can translate into P&G for cyclists. Going up the hill is the pulse, going down is the glide. And on flats with the drafting and the leader, you're still doing P&G to some extent!

What I haven't been able to figure out is how to approach hills. Someone mentioned in this thread that P&G is applied to hills--I'd love to know all the variables and concepts that go into that--what do you do on really steep hills--what about long gradual ones? (hope someone bothered to read this long rambling post!)

[1993CivicVX]

Originally Posted by popimp

The speed limit is the upper limit not the lower. Unless there's a minumum speed limit then you have every legal right to go under the speed limit. People don't care because gas is still too cheap. Give it some time and they'll figure it out.

I am not a true hypermiler... hehe. I cannot bring myself to employ these tactics while actually driving. I do sometimes if no one is behind me on a back road, but if I have cars behind me I won't do less than 5mph over the speed limit for any duration of time. I once got pulled over for doing 40mph in a 55 (not an interstate, not a two lane highway) As far as I could tell I was driving within the limits of the law. I wasn't going excessively slow, no lower limit speed was posted (sometimes you see 40mph or 45mph) and I was staying within the lines (granted I was hugging the white line and then the yellow line) the cop thought I was a certain DUI. Took some talking out of to convince him I had too much time to get to the train station and wanted to save gas. Driving that slow is really boring so I was using the whole lane....

I can only drive miserly for so long before I start to drive myself crazy, and then I'll tromp on the accelerator a bit. Once I get it out of my system I can go back to watching my foot.

[oneinchsidehop]

Originally Posted by veloman

From my experience in road cycling, accelerating to a high speed and coasting back to a low speed and repeating is the best way to have a horrible average speed and waste TONS of energy. I can't see how it would improve fuel economy in any way. BUT, I've never tried it, so maybe you guys are right.

When you change velocity, that requires additional power. I would think it's far better to maintain steady speed/power levels.

And how practical is it anyway? Are you going to yo-yo down the road in traffic? Dip to 45mph on the interstate and get run over? lol

I'm a cyclist too. There are a lot of correlations between riding and hypermileing but a few important differences, most of our ICE engines put out about 60-120 hp and 40-100lbs of torque (I know most of us dream of 100lbs of torque). Our legs put out about .5-.75 hp peak and .05 spinning. and torque? I'd rather not think about it, it's just too embarrassing for me.

P&G uses the torque peak to pull the car up to maximum efficient speed and the shut off the engine to milk the momentum (and the terrain) rather than run steady state in a less efficient range for the engine. It doesn't work well on a bike because it causes you to exceed the aerobic (and torque peak) efficiency of your system, moving into anaerobic. Watch kids ride to school, they pedal lightly when it's easy, walk up hills and coast down anything as long as they can. That's P&G. Efficient, but it won't get you props in the peloton.

A better correlation would be BMX dirt jumpers who use almost no pedaling but inertia to carry them from jump to jump. Or for a more Velo look at it, track cyclist who drift to the outside on the straight, ride the bank as high as they can and then rocket down the bank to pass taking the next turn tight inside to keep their lead and time down.

BTW, the most efficent P&G in my experience has been from about 40mph down to 20mph, evidently because my car is about as aerodynamic as Homer Simpsons buttcheeks.

[sipnciv]

I have been doing well going up to 5-10mph over the limit and coasting back down to the limit or 5 bmph below, depending on whether there is traffic behind me. I usually will go back on the gas early if someone is coming up on me fast. I will coast a little longer if nobody is on the road behind me. I coast downhills, and on some flats once I'm back to speed. I accelerate going
uphill just enough so that I hit my target speed at the top. I will usually start speeding up at, or near the bottom prior to starting up the next grade unless I've still got alot of speed left to coast on.
I get over 4mpg extra, from doing this, and it takes the same time as if I just stayed at the speed limit the whole way. This is a 76 mile each way commute that I drive 2 times each week.

It really works, you will get better with practice.

One time I went the long way around the beltway. It was 84 miles long.
I counted the miles that I coasted with a goal of 30 starting out. I stretched a couple of my coasts alittle longer than I usually do so that I could achieve my goal. I forgot to mention, I changed my goal to 40 after I hit 30 with lots of miles left. I coasted to a stop at 41 total miles coasted for that 84 mile trip. I added the miles in my head as I drove and made the numbers a little song as I went each tenth of a mile. I wasn't bored at all.

[diamondlarry]

Originally Posted by 1993CivicVX

I find it interesting there is no talk about Hybrids on this website. I have to mention this tho from driving my mom's '07 prius: In the '04 and newer Priuses, pulse and glide is easy between 29 and and 41mph. By slightly depressing the gas pedal you can coast--effectively be in neutral while in drive. But it's nearly impossible to coast by using the gas pedal at speeds higher than 41mph. For some reason Toyota made it so you can't easily find neutral by slightly depressing the gas pedal--you'll either be regenerating the battery or be accelerating. Is it bad or somehow disadvantageous to put the car in neutral when coasting at speeds higher than 41mph? And then putting it back in drive BEFORE you need to brake? It seems to me this would be more efficient than leaving it in drive and either be slowing down by the automatic brake regeneration that the Prius does when coasting in drive or be slightly accelerating with the electric motor. Anyone know what I'm talking about? Anyone know if it's for some reason not more efficient to put it in neutral at speeds higher than 41mph?

I see that no one has addressed this so I'll take a stab at it. Actually, you can coast at any speed below 41.5 mph. The reason for the 41.5 limit is to protect the one of the electric motors from over-spinning. I'll see if I can find the link but there is a guy that goes by hobbit who is able to explain these things far better than I can. With that said, hobbit has had his car up to ~60 mph in neutral before with no ill effects. You can do this by cresting the top of a hill at 40 mph, enter the glide, then shift into neutral. I'll go look for that link now.