Featured Series of Articles About Hypermiling

Wouldn't that be pulse and screech.

There is some benefit to following a truck or bus at the legal distance.

The term hypermiling is new, but efficient driving is not. I remember a Popular Mechanics article from the '50s that described pulse and coast, but no luck finding the post. I did find this, printed in 1950.

 

Chuck, read the article. Rule #4 is "Don't be an nice person." No one is calling you a jerk.

 

Driving with the Engine off - Is it OK?

It depends - read on.

Gas rationing was done in the US during WWII primarily to save rubber, but saving gas was a good thing. In the couple of years the Big Inch pipeline was constructed from Texas to the East Coast, tankers in the Gulf were vulnerable to U-boats. What many drivers did was drive to 20 or 30, then shift to neutral, cut the engine, coast, repeat. This is the earliest I know of this technique. A number of states have laws against this. Decades later, this became "an advanced hypermiling technique."

How does this save gas? Remember a conventional gas-powered car's engine is built to get you up to freeway speed in a reasonable amount of time - not cruising. I recall in the mid-70s, Reader's Digest mentioned it as an emergency tactic when running on empty to increase your range up to three times. Depending on your car, there might be loss of steering and/or braking. I admit to doing this on my 2000 Honda Insight. I made it legal with a kill switch that keeps the steering and brakes 100% functional while the engine is off.

If you drive a full hybrid such as a Prius, you can do this and be completely legal. There is the window - usually narrow between the electric motor charging or engaging, takes a little pedal work. For all intents and purposes, the hybrid is in neutral, although the electric motor while off may be spinning. This will bring down the battery pack, but not as fast as when the motor is running.

Shutting the engine down at intersections is a different matter. Did you know the Canadian government actually encourages it for even non-hybrids? ( Is it more efficient to leave your car idling? ) The link just mention somehow thinks restarting the car require 30 minutes of gas - usually a half gallon or more. In carbonated cars, it's 30 seconds - 10 seconds for fuel-injected vehicles. It actually slows down the fouling of the internals of the engine. Moot issue for hybrids as autostop takes care of it.

The practice of manually shutting down a car and coasting in neutral will be less common, esp in the US, as keyed ignition is quickly going the way of mechanically cranked door windows. Most new cars do not use keys.

 

Who knew the word "hypermiling" would cause so much fuss? I wish Wayne had coined some other term, perhaps "economical driving"? The problem is that "hyper" carries the connotation of "extreme". It comes from a Greek root meaning simply "over" or "above", as in "more than typical MPG" which is how Wayne meant it. And journalists, with their typical flair for exaggeration to sell papers, attributed all sorts of extreme behaviors to hypermilers. In this hysteria, anybody who ran a stoplight or stop sign must have been a hypermiler.

Another confusing aspect is that hypermiling involves a set of techniques, not all of which work for every vehicle (or driver). The "toolbox" one has to work with is different for a conventional car (and differs for MT vs AT), an Insight-I (different for MT and CVT) and a Prius (probably varies between different Prii). For example, pulse and glide worked for me in my Subaru Outback MT (got me from about 25mpg to 35mpg on highway trips) but I could never get it to work for me in either the Insight-I MT or the Gen 3 Prius. Maybe others found it more useful? OTOH, coasting engine off on the highway in the Insight-I MT (I had MIMA so it was seamless) worked great, impossible in the Prius because there is no real neutral and the Gen 3's engine cut in above 46mph. Lean burn also a great tool unique to the Insight.

My favorite MPG tools in my Prius "toolbox" are:
- Running on battery around town (I use a Scangauge to monitor gas engine rpm so I know when it is off) - can't do that in an Insight-I or any other Honda hybrid AFAIK - depending on the terrain and speed I can go a few miles, after which hopefully a hill or something requiring more load than the battery can handle will force the gas engine to kick in and recharge the battery
- On the highway, coasting downhills in neutral - at >46mph in the Gen 3 the engine won't shut off, but, according to the Scangauge, coasting in N rather than in D cuts fuel usage roughly in half** - obviously the downhill must be steep enough to maintain one's cruising speed, and if the downhill is much steeper it may make sense to leave the transmission in D and regenerate the pack

A few things are common to all vehicles, like not speeding, scanning ahead to plan braking to get max regen and avoid having to stop, being aware of traffic behind on 2-lane roads so one can dip below the speed limit if nobody is following, moderate starts and accelerations, staying in the far right lane on multilane highways, keeping an eye out for downhills steep enough to coast or better yet capture regeneration (for hybrids).

Benefits:
(1) Far less stress, so one arrives rested and relaxed. Driving 80-85mph as I used to do, scanning everywhere for cops, is exhausting even if you escape being ticketed as I did (mostly).
(2) Obviously saving gas.
(3) Not having to stop as often for gas.
(4) A game that makes even the dullest trip or the daily commute more interesting.
(5) Tires last longer: my OEM Gen 3 Goodyear Assurance still had 4/32nds-5/32nds after 50,000 miles (digital gauge). Incidentally, wear is dead even across the treads despite running them at 45psi (my Insight-I OEM Potenzas went 70,000miles and had wear left, wear was likewise dead even at 65psi).
(6) Brakes last longer. My Gen3 brakes were at 8mm fronts, 6mm rears remaining after 50,000 miles.
A set of tires costs $500? and a brake job for all four wheels even more? These savings loom large and usually aren't added in when people compare MPG savings.
(7) Driving more slowly doesn't take as much longer as you would think from calculations based on max MPH and distance. For at least two reasons: (a) there are stretches of slower secondary or urban roads at both ends of most trips (and sometimes in the middle) and (b) when I thought I was driving 80-85MPH I actually was frequently forced to slow down to carve through knots of traffic, so I was not averaging 85MPH on the highway. Now as one of the slower vehicles on the road, I rarely have to slow down. Besides, varying speed in an irregular unplanned way (as opposed to pulse and glide) wastes gas.

Slowing down was hard for me. I had to set cruise control and keep my right foot planted on the floor (unless I needed to brake, obviously). Eventually I got used to it, came to prefer it, and haven't had problems in the 10 years I have been doing economical driving or whatever you want to call it.

** - an oddity is that fuel flow (GPH) on the Scangauge never goes to 0 even when RPM=0 ! When the gas engine is off, the Gen 3 shows 0.02GPH, the Gen 4 ECO shows 0.04GPH. I wonder if this is a sort of "placeholder" to ensure that the OBD system doesn't get an infinite value in it from dividing by 0?

 

Exactly.It went from hype of some of the most controversial aspects, to ignorant reporters copying those articles or with a bias against it.

Should you be afraid to Hypermile?

No

For all this discussion on the techniques, it starts with the driver being willing to hypermile - that simple.

Previously, we have discussed doing everything to let other drivers pass you, yet I have seen countless posts over the past decade over the fear of hypermiling, or to be very blunt not speeding along with the pack. Some of these people online are actually speeders attempting to justify what they are doing - scared a lot of people will no longer break the law with them. For those that are interested and have fears keep these things in mind:

1. Again, you can do everything to let other drivers by.
2. You can pick times and paths to reduce the number of impatient drivers behind you.
3. Many people simply don't give enough time on their commute or unfamiliar with the commute.
4. There are a number of people that simply should not be driving - not scientific, but I'd say 5%-10% depending on time and locale. Too sleepy, drunk, on drugs, distracted by a device, young 'men' that think reckless driving makes them powerful, beat up their girlfriend...
5. That driver is going to kill you. Quite unlikely. They are just going to tactlessly peel away from you, and maybe you will meet them at the next stoplight!

While driving a car like the Prius might subject you to additional harassment, everyone must endure it, unless you are the most reckless driver on the road who will eventually get pulled over. The online proponents of driving with the pack at times try to make it seem every tailgater has a pistol in their glovebox. If you are driving at or close to the posted speed limit and letting others by on a multi-lane road, you are not going to die.

You may choose to look at this spiritually - should a commute be stressful? I personally find myself less tense when I slow down.

 

Recently I have read up on roosters. They remind me a lot of aggressive drivers. Roosters are hard-wired to protect hens, the intensity depends on the breeding. Keep in mind this is a seven-pound bird with a gum-ball sized brain overwhelmed by testosterone. Some are man-fighting roosters, they mistake humans for competing roosters. In some cases, this can be resolved by standing your ground and not fighting back...that's my usual tact when dealing with aggressive drivers. Don't get in their way or be a threat. But sometimes I hope a cop will "clip their wings"