racers line and ecoline minutia
 

It seems racers line is a general term that to some people means cutting the curve at the shortest radius to the end up with the shortest distance traveled.
This definition has little to do with what racers actually do, (although I am not a racer)

This makes sense only on the highway with big sweeping S curves and little traffic. I take advantage of this when I can also.

As some have stated on exits, entrance ramps and curves, maintaining inertia and momentum is best achieved by staying off the brakes and taking the outside of the curve at the max radius and safe speed.

As smart combination of when to employ which line can make a big difference.

Also, the cross section of most road lanes is shaped like subtle "W" with the two tire tracks at the bottom. In some cases on asphalt in MI with heavy truck traffic this can be substantial, sometimes a couple of inches which creates a side slope angle or "banking" . I try to use this banking on curves without forcing the wheel. Sometimes I cut the corner line and then let the car float to the very outside and pick up the banking on the outside lane.
Left tire just left of the center of the lane and the right tire just short of the right edge. Many times the car tracks without any input from the steering. Less resistance.

Taking this W to city driving, I move to the top of the W at stop signs and traffic lights if I can, making sure the car is stopped heading in the exact direction I want to accelerate in . The tire resistance of turning at slow speed helps stop the car and avoiding any turning during accel helps too.
Raising a 4000# car an inch or 2 burns off energy and this is recovered moving to the tracks at the bottom of the W.
At stop signs where I am going to turn at, I make as much of the turn when stopping as I can so there is less of a turn during acceleration. When accelerating I go as straight as I can and delay finishing the turn to the edge of the lane. Minutia I know, but it has become a habit and I don't think about it much, except that if everyone did it it would save a bunch of fuel

More minutia, drive to the top of the W at the bottom of hills and bottom of the W at the top of hills.

A movement for a legal "energy stop" would be great. Make it OK to slow to 2 mph a minimum of 20 ft from a stop sign and roll through. Even if it was just when there is no other traffic at the stop sign. Topic for another thread

The racing line is not travelling the shortest distance, but making sure you go as fast through a corner as possible. What means that the racing line goes from outside of corner to inside (apex) and to outside again. The biggest radius is achieved this way. By taking th biggest radius through a corner there is also less tire drag and more momentum to take out of the corner.

It's the same, most of the difference is when I am driving I sometimes make my wife gasp. When I'm racing she would pass out and I would be gasping. If it was me I'd get rid of every stop sign in residentail areas and half the lights on the main roads. Got snagged today by a red light that is so stupid, the guy that tripped the light made a legal right hand turn on red, the light only served to make several cars going 45 slam on their brakes. There are whole areas of tidewater va that I generally avoid because they couldn't time a light if their lives depended on it.

regards
mech

Exactly, Thanks for the clear definition I think many where confused.

Normally people slow way down to make a turn it is annoying. I think us hypermillers make up the time from going a little slower on the straightaways in the corners.

I really try not to brake before a turn because I know all of my speed will drop in the turn. I will try to slow down before if I am going to fast. I love it when a fat SUV is on my bumper going 45MPH in a 45MPH zone and its a sharp turn I make a huge gap again just for them to floor it to catch up.

Re: the W cross section.
The ecoline is different and probably better than the racing line or cutting the corner for FE given the rut tracks in the road. We are generally much slower than the road can handle. I think it is better to stay in your own lane and bank within the lane on the "W". Crowd to the right of the lane on a left curve and crowd to the left of the lane on a right curve. This is opposite of intuitively cutting the corner which causes negative banking from the "W" and crossing lanes can cause the car to dance a bit and require more steering input and scrub off speed.
I am sure this should be posted in a hypermile thread instead of here. sorry
Does anyone have an opinion of whether P&G would be effective at all with an automatic transmission and not doing neutral coast or EOC? I know this may be very vehicle dependent.

I have a lot of fun on one route home. I turn off at a sharpish corner and go into tighter corners, small hills and whatnot. I'll hold near 40 all the way through, and it's a couple miles after that turnoff before there's enough straight that the guy that was riding my bumper even comes back into sight.

And before that turnoff, he was probably complaining that I don't know how to drive. :)

You don't want to use "racer lines" to hyper mile.

Can you explain why you don't want to do that?

Actually the best racing line through a corner is not the line with the biggest radius!

It would be if the speed was constant before, during and after the corner; which makes it a good approximation of the ideal line for hypermiling.

But in a race you enter the corner still braking, and exit it while already giving it throttle.
The speed in the apex needs to be slightly lower, so you can brake longer before the corner and accelerate going out.

I did not win 3 F1 Championships, but take it from someone who did: http://www.youtube.com/watch?v=WhgOXVnHYXA
Now its not just the line you take, but also the speed at which you (try to) take it. The closer the speed comes to the limit of what the tires can bear, the higher the friction will be trying to slow you down.
You can compensate that with gentle throttle, but hypermiling is all about maintaining momentum through efficiency, not extra throttle.

If your speed was already low enough to go round the corner without tire squeal the biggest radius would be close to ideal.
If you have more speed you might choose a line that starts at a bigger radius (entering the corner slightly earlier at higher speed) and allow the friction to gently reduce the speed, and radius, throughout the corner; especially so if you do not need to speed up in the section after the corner.
Then there are corners where the road surface is not even, like the OP pointed out. Better run that ridge if it does not violate the ideal line too much...

There is no simple rule of thumb to prescribe the ideal throttle, line and speed for hypermiling corners, just like there is none for racing them; because in both cases there are too many variables at work.
Which makes hypermiling a true skill, just like racing.

There is a lot we hypermilers can learn from racing.

The racing line | Taking corners at speed | drivingfast.net
Racing apex is typically later in the corner to allow for more throttle on exit, where I think the hypermiling apex would be the geometric apex

For practical purposes I'm going to refer to a single corner with higher straight away speeds (entry and exit) than corner speed to keep things simple.

A racing line assumes a few things. One, you are entering the corner a lot faster and two you are exiting the corner a lot faster while also trying to maximize your speed down the next straight by "driving" the exit. And three, the racing line is not about saving energy. It's actually all about using all the energy at your disposal. And lastly the racing line is a very flexible thing. It changes considerably from car type to car type. Car to motorcycle, etc. You can't look at a track map and simply draw the perfect racing line, no matter how much experience the driver has. You have to get out there and "feel it".

The goals of hypermiling (HM) are a lot different. The goal is to use the least amount of energy as possible. The easiest way to do this is to not slow down for the entry and not speed up for the exit. Of course in a lot of situations that is not possible, the corner will be too tight. So you have to figure out how you can get as close to that goal as possible. And a lot of that is going to come down to feel. You have to be able to feel when you're scrubbing speed (loosing energy) so you can retain as much momentum as possible.

The feel is very, very hard to explain. You can read 100 books on how to go around corners and I will still be able to teach you more about the subject in one day of hands on driving instruction. It's all about the feel.

You can absolutely learn about going around corners efficiently by reading about it. It is important to understand the vehicle dynamics, techniques, etc. But unless you take those lessons and go out and practice and feel them you will only have a very rudimentary understanding. Driving fast (or in this case efficiently) is a lot like sex. You can explain sex to a virgin for years and years, show them movies and even have doctors come in to explain the mechanics of what the body goes through. But until they actually have sex they simply won't understand.

I professionally road raced for 10yrs. Won championships, lots of races, set lap records, etc. I've worked as a driving and riding (motorcycle) instructor. I've also worked for Pirelli and Michelin as a tire tester and Ohlins, Penske and Matris as a suspension tester.

I've just started this hypermiling thing when I got my Focus. One of the first things I did was figure out how to go through corners as efficiently as possible. I assure you it is not the same as a racing line. You can use racing line and vehicle dynamics knowledge as a spring board to feeling out the "efficient line", they are quite a bit different though.

I disagree. There is a simple rule of thumb for hypermiling. It is to slow down as little as possible so you don't have to speed back up.

The trick is figuring out how to do that.;)

That's backward, you early apex a corner so you can get on the gas sooner.

You are correct though that you are shooting for a constant radius when hypermiling (in most corners).

No, he's correct. It may sound counter intuitive but the apex is later in the corner if you want to hit the gas sooner.
The apex is where you hit the inner limits of the track. That is not the point where the radius is smallest, unless you do a neutral corner. If you get on the gas early, or late, the point of smallest radius moves one way and the apex moves the other way.

You've seen that link 2000mc provided? That should make it clear.

I think the problem here is how some people define early and late apex, it's common.

A lot of people (and what is happening here) describe early "turn in" as a early apex. They are not the same thing.

The apex of your line is not the same as the apex of the corner. If you early apex a corner you get the turning done (or most/more of it) before the apex of the corner. This straightens out the exit and allows you to get on the gas sooner. This is how you drive/ride something that has more power than lateral grip. Motorcycles (especially fast ones) and NASCARs for example.

To early apex a corner you delay your turn in (effectively "blowing it"). Then slow down a little more to sacrifice apex speed which allows you to turn in/more faster. Get your turning done real quick, straighten it out and dive hard through the corner onto the next straight bit.

In NASCAR is it called "backing the corner up". They apex early (before the actual apex of the corner) and then drive it down the next straight. backing the corner up means they are getting the turning done earlier. You will see them do this a lot at the shorter tracks.

If you are early apexing a corner correctly you will be hard on the gas as you pass over/by the physical apex of the track.

A lot of it is symantics. I can assure you in the racing community most people describe an early apex as turning before you get to the actual corner apex.

This for example is not how most racers talk to each other. Note in the diagram that they are calling it a late apex because they are referencing the track/corner. When racers talk they reference the line, which is the only thing that matters.

It's a widely mis-used term(s). But just because "everyone does it" doesn't make it right. What matters is what is actually happening. And what is happening is your line is apexing early (before the apex of the corner).

http://www.modernracer.com/tips/properapex2.jpg

I think it's easy to have the terminology twisted around, which is why I also put up the link. Looking at the shape of the path the car follows, it makes more sense to call the apex the point where you are turning the sharpest. For whatever reason I always have, and what seems to be at least a lot of people call the apex where ever you hit the inner most point of the track in a turn, but looking at the path of the vehicle, it doesn't make sense

Wikipedia uses clipping point as a synonym for apex.
So the apex is the point where the racing line hits (clips) the inner boundary of the track. It has nothing to do with the point where the turning radius is smallest, whether such a point were easy to determine or not.

You can call it whatever you like. You can be the "rightest" person to ever post on this board. I'm OK with being the fastest.:D

I did not make it up, I just recall what others call apex.

This is how you want to hypermile a corner if you can't take the corner at the same speed as the entry/exit straight. This will give you the best "roll" through the corner.

Constant radius as smooth as possible.

The faster you take the corner the less energy you use.

http://www.mytrackschedule.com/images_NG/image01.gif

That is what I explained in the second post, only without the image. So the racing line is the same as the hypermiling line, the braking and stepping on the gas is ofcourse completely different. But the lines are the same, in both situations one is looking for the ideal line through a corner.

On a very basic level yes. But you will find that most corners are not shaped like that.

Don't forget that the most important thing is feel though. A diagram will not get you through a corner 100% correctly. Only feel will do that. You need to build an internal database of what works and what doesn't based on feel.

Racers accelerate through the later part of the corner and out of it to maintain max speed and momentum when FE is not a concern. For eco I think it is better to coast to the outside and delay accelerating until after the minimized turn scrubbing is complete and the wheels are straighter.

Also, some more minutia. This week I added some tape(actually a sticker strip from my postage stamp pack) to the top center of the steering wheel, ala NASCAR, lol.
It is amazing how much I now notice the amount of rowing and steering input I used. This has helped a bunch in minimizing the amount of input and over steering and correcting that I do. I was turning a bit too much, too soon and then over correcting. The tape really has helped my technique. I look further down the road now, like 200 yards and point the steering wheel there. It takes a moment, but the car finds its way there with less tire resistance and a much smoother ride

I've been playing with cornering techniques for eco since I last posted in here. Lots of playing with it. I have a pretty good system down now. It's not a "racing" system, but I used racing feel to come up with it. They do have some things in common, but for eco there are some tricks. You statement above is one of those tricks. It's a good "tool" to have in your "toolbox".

I am planning on writing something up, but it will be really time consuming and I have been slammed busy.

We just took delivery of one of these for some testing and product development which has been keeping me busy:

http://i1248.photobucket.com/albums/...psfdc9a88e.jpg

http://i1248.photobucket.com/albums/...ps053e83f9.jpg

http://i1248.photobucket.com/albums/...ps40366576.jpg

Yeah, I'm showing off a little!:D I really like the new car though. It makes my previous generation Mustangs feel like they were made with a nail gun. This one is like it was carved out of billet. It may not even be a muscle car anymore. It reminds me a lot of my friends Aston Martin Vantage, but a whole lot faster!

I love that piece of tape! I have it on all of my performance cars. It's amazingly helpful. And also is good if you do your own alignments.:thumbup:

Can't wait for your compendium on it.
Nice 5.0

I work in A2 also

Yaaay...I am doing it right!

I propose a slight alteration. As a hypermiler/ecomodder, I'm not interested in powering out of the corner, just getting through it while maintaining the most momentum. (I'm in neutral, engine off ;)) Going through the corner, I will be losing speed. Therefore, I can take the later part of the turn tighter than the first. This leads me to adopt a slightly "early apex" approach where I come in straighter and tighten the turn as I come around.

Admitting that you're going to lose some speed in the turn is the first step toward taking a line that loses less speed in the turn.

You will lose some speed even rolling straight. You lose even more in a turn thanks to tire scrub, both due to sideways slipping and the non-parallel paths of each turned front wheel and straight rears.

Pet peeve (that diagram reminds me of it): Not a big fan of drivers that, say they are maneuvering that turn in the diagram, slide WAY out left before diving in to the apex without using a blinker. Some will even put their tires in the next lane doing this. Annoying and dangerous. That is all.

Yes. Keep it between the lines.

This is an interesting thread as I spent years studying vehicle dynamics. The eco line combines or balances the minimum distance traveled and the minimum need for applied power. If your alignment is correct and the tires neither are spinning or sliding then scrubbing losses are minimal.

Arent the tire scrub losses in the corner a function of the g force generated? That is the faster you go the harder the tires have to work to keep on your cornering line? The more energy is wasted in heating the tires....the goal should be to balance conservation of momentum with minimizing tire scrub....conflicting requireme`ts to be sure.