Started tracking my mileage

[hammsaveo]

Most hypermilers won't be found going 65mph... In fact most consider 60 to be speeding or just a mpg waste.... It is an extreme way to drive there for you can get extreme numbers! Having the right equiptment doesn't hurt either.

[serega12]

Most hypermilers won't be found going 65mph... In fact most consider 60 to be speeding or just a mpg waste.... It is an extreme way to drive there for you can get extreme numbers! Having the right equiptment doesn't hurt either.

Explain "hypermilling" and "the right equipment".

[petrified.rabbit]

i dont feel like i have enough time in my life to drive slower to save a few dollars at the pump..

[hammsaveo]

Hypermiling is all about driving easy and trying to squeeze every last mile out of a gallon of gas. You coast as often as possible. some with the engine off in neutral. You leave windows up and no mpg killing ac if you can help hit. Most will also go with out cc so they can feel the pedal better and not waste an oppertunity to coast. You time stop lights better so that you don't come to a complete stop(kills your mpg to stop) You shift at low rpm's without lugging your engine. You park your car just so that you can drive right out of a parking spot to not waste gas backing up. When going into town on a short trip to run arrands you go to the farthest place first to allow engine to warm up to get max mpg. Some will use a engine block heater year round 2 hrs before they start there car to have max capability of getting top mpg numbers. All these things to save the conumption of gas... Now By the right equiptment I mean Having a good mpg vehicle to start with.The prius,honda civic hybrid and insights are all major mileage cars to start,with these tricks that take time to master you can pull in some cases over 100 mpg. The honda insight gen 1 for instance... some have a life avg of numbers in the 90's... If you search the web for mpg sites you will see some have gotten 125-150 mpg on individual trips using a scan guage. Look up the Wayne Gerdes online and you'll see everything you would like to know. Now some think it is all a lie and so extreme it isn't an everyday way to drive and I will tell you it is a very disiplined way to drive trying to not waste an ounce of gas.

[hammsaveo]

Thats another thing time...you allow for it. Leave early and so on.It becomes a game after a while trying to see what you can do with your vehicle.

[Daox]

Well, I'll likely have some surprises and disappointments for you. But, here goes.

Lets start with the bad:
My commute is roughly 21 miles one way. It is mostly highway, speed limit is 55 and I drive 55. Going 60-65 would save me a whopping 3-4 minutes on my normal 35+ minute commute. Its not worth the time or the hassle/frustration of trying to get around slow drivers and bad traffic IMO. Been there and done that, now I relax and hang out in the right lane most of the time.

Aerodynamic drag is huge. It increases at the cube of speed, so slowing down even 5 mph can give you very respectable gains. This is why all the high mileage cars look all swoopy and stuff, aero matters big time. Even at 35 mph, nearly half of the power the engine is producing is going towards overcoming aero drag. If you can reduce aero drag the engine doesn't have to produce as much power and therefore doesn't have to burn as much gas.

Here is a readout of the data from a calculator on ecomodder. This chart is for an 05 Aveo. As you can see, going 55 mph takes 12.27 hp (roughly). Going 60 mph takes 15.23 hp. That is a 24% increase in horsepower to go 10% faster. As you can see, we're on the down slope here.


I also minimize brake use as much as possible. Going 55 mph helps a lot since I don't run into people going slower than I am real often. If I see brake lights ahead I get off the gas right and coast in neutral. The same goes for the few miles of city driving I have to do on both ends of my commute, and its much more important in city driving. When I see a red light ahead and I shift to neutral and coast. No point in using more gas just to stop and wait. I watch people every day pass me only to have me catch right up to them at the next light.


Now for the good news.

You do not have to accelerate slow to get good mileage. That accelerate like a grandpa stuff is total BS (although it does aid in reducing brake usage). An engine runs most efficiently at nearly wide open throttle (as long as it stays in closed loop mode). Here is a chart (2.0L Ford Zetec) that basically shows how much gas is used to get so much power. As you can see on the graph, higher engine load (IE putting the pedal down further, the vertical on the graph) shows you use less gas for the same amount of power. Its only until you start getting your rpms really up there that it starts to fall back down. Fast acceleration (red line) is much more fuel efficient than slow acceleration (blue line).



I have saved over $1k in driving efficiently with my Paseo over the past ~2 years, and only really drive it 2x a week. IMO its worth it and it is fun. Like hammsaveo said, it kinda becomes a game to see if you can 'top your high score'.

[hammsaveo]

Thanks for the help and charts Daox. Can yu explain what open and closed loop are to me.?

[Daox]

Closed loop and open loop are two modes of engine operation. In closed loop the ecu mainly uses the oxygen sensor to regulate the air/fuel ratio keeping it close to 14.7. In open loop the ecu mainly uses the map (or maf) sensor to determine how much fuel to inject. Normally this is in situations of hard acceleration & high rpm where you need to run a richer air/fuel ratio under 14.7. Under these heavy loads the engine actually uses this additional gas to prevent engine pinging. Its not necessarily all going to produce power and therefore is less efficient.

[serega12]

Thanks. I'm not quite sure I'm ready for the "game" though.

[hammsaveo]

Was going to say nice lookin car serega12