Problems with Pulse and Glide.

[JRMichler]

It sounds like you are doing everything you can do with the vehicle you have. Engine off coasting might help, but your coasts are short, so it will not help much.

A streamlined boattail is the next step even if you mostly drive at lower speeds. My truck's mileage is sensitive to wind even at 25 MPH.

[twj347]

Originally Posted by oldtamiyaphile

Most petrol cars will run open loop (rich) after a restart, which may be enough to counteract any gains from short P&G cycles.

Not sure about all cars, but my O2 sensor is warm enough to run closed loop within a few seconds of restart if my engine is hot. Also, closed loop does not necessarily mean rich. The ECU will still target an AFR of 14.7:1 at low loads, but may be a bit rich if the MAP or MAF scaling is off. There are also post-start enrichment tables. For my for my car, post-start enrichment only lasts for 5 seconds and injects 2% extra fuel during this period (with coolant temp over 80 degrees C.) The extra fuel will be really minimal, even with shorter P&G cycles.

[JockoT]

Originally Posted by JRMichler

It sounds like you are doing everything you can do with the vehicle you have. Engine off coasting might help, but your coasts are short, so it will not help much.

A streamlined boattail is the next step even if you mostly drive at lower speeds. My truck's mileage is sensitive to wind even at 25 MPH.

Thanks. I don't do EOC (steering too heavy) and I have no urge to do body mods, so I guess I will have to do the best I can with what I've got.

[jcp123]

Reading the hell out of this. And going to re-read when I'm driving my car again (out trucking right now). I similarly don't quite get P+G.

[Magician]

It's just what it sounds like. You pulse or accelerate up to a certain peak speed... then you coast with the car out of gear while engine idling or (EOC), allowing the car to coast until the speed drops to a certain low mark. You can make the gap between top and bottom speed a 15 mph difference, or whatever you feel most comfortable with considering the traffic. Then, keep repeating. This is more efficient than driving at a set speed... apparently around 20% more efficient. This is a very effective technique for city driving, but can be used on the highway as well. I found this info elsewhere on this site and have found it to be pretty accurate.

[elhigh]

JCP,

You can engine-off coast your Honda if you think it will be worth the risk, bearing in mind that if you turn the key a notch too far, you lock the steering. One click, not two.

Don't try to engine-off coast your Echo. Automatics need to be kept turning by the engine to maintain lubrication.

Aero improvements make P&G work even more, because you get to retain more of the velocity over a longer glide than before, and you need less input energy to overcome aero drag to get back up to gliding speed.

[Magician]

I never use my ignition switch to turn off the car for EOC. I have a toggle switch so it’s not a dangerous action... and my Honda is a manual and it doesn’t have power steering... and your brake booster allows at least 3 presses of the brakes before you lose the boost assistance.

[JockoT]

Originally Posted by elhigh

JCP,
You can engine-off coast your Honda if you think it will be worth the risk, bearing in mind that if you turn the key a notch too far, you lock the steering. One click, not two.

My steering lock only works if the key is removed. I can turn the key two clicks, and provided I leave the key in the barrel I can turn the steering from lock to lock (not easy when the wheels are on the ground), and the lock will not engage.

[JockoT]

I have been working on my highway driving technique and have come up with what is a "sort" of Pulse and Glide which works for my car and on Scottish roads.
I am currently monitoring instantaneous MPG and Manifold Absolute Pressure on my ScanGauge E (Average MPG shows as a bar graph too), and the procedure I have found effective is to reach a comfortable speed then ease back on the throttle for a MAP of about 4 - 6 psig. Once the speed slowly drops back to what I consider the slowest suitable for the road and the traffic, I increase the throttle for a MAP of 11 - 12 psig. With that amount of throttle the speed happily builds back up to the top value and then I can repeat the process again.
Obviously I take advantages of down grades, by either DFCO or coasting, but most of the new highways around here have very slight grades, making use of cuttings and embankments.
I had an 86.7 mile journey this morning. Being a Sunday, the roads were not too busy, and a couple of stints behind big trucks helped me push my average mpg (as computed by the ScanGauge) to:
65.1 mpg (UK)
54.2 mpg (US)
4.34 Litres/100km

Pretty pleased with that.

[Magician]

JockoT, that’s fantastic!