How to Become a Hypermiler

Step 11 Pretend you have no brakes

If you didn't have brakes, you'd only go as fast as you needed to ensure you could stop at your next destination. That is, don't apply so much power that you'll only be throwing away your engery VIA braking.

Coasting is your friend.

Comments

[mijhy]

I must agree almost fully on this step. In any type of automobile there is a "peak efficacy" zone where the power required and drag created are balanced out evenly. Usually this is somewhere between 45 and 55mp (each car is different). Going faster does NOT mean your more efficacy. This is especially true in pickup trucks suv's and vans as they create an enormous amount of drag.

To reference the comment about jets, speed is certainly not the reason they are efficient. I wont go into a big debate on how a high bypass turbo fan works, but the efficient is due to the design of their operation not the speed at which they operate. Jets have the same "peak efficient" zone as any other mode of travel does and this is most defiantly not at full throttle. It is also worth stating the aerodynamic properties of the plane it self is just as much of a contributor to its efficacy than the engine its self.

But you still shouldn't impede other traffic just because you want to save 10cents at the pump.

[Outlander]

Remember this "the faster one travels the less fuel one uses." The sole reason why jets are more efficient than prop planes, because they go faster. If a Jet consumes say 30gal/hr and takes only 1 hour to get from point A to B is only uses 30 gallons. If a prop plane uses say 15gal/hr, but takes 3 hours to get from point A to B, than it has consumed 45 gallons. Very simple really. The less time one spends worrying about driving like granny, obstructing traffic, and causing 5 O clock rush hour, the less fuel one will waste. especially when one has a .73 final ratio and 2.41:1 gears, 75MPH is much more efficient than lugging it out at 55MPH. Don't get a ticket!

[Damian7]

i used to drive most of time time at 65-70 mph where allowed and would get an avg. 30 mpg. I read a couple of articles about Hypermiling and tried simple things like slowing down(55 mph), rolling up windows, etc. Now I'm getting 35-40 mpg. I see cars flying next to me and I just think how dangerous and wasteful that is. I don't know a lot about planes or whatnot but it has worked for me.

[trebuchet03]

The sole reason why jets are more efficient than prop planes, because they go faster.

Utterly false. The reason a jet's power train is more efficient is due to a more efficient engine cycle. It's quite clear that when your instrumentation reads 30mpg at 80mph and 40mpg at 40mph in the same gear with same environmental conditions which scenario is more efficient.

Again, you're comparing different engines on different planes and relating fuel consumption to that. I would not expect an otto cycle (prop plane) to be more efficient than a rankine cycle (turbine engine) engine.

The less time one spends worrying about driving like granny, obstructing traffic, and causing 5 O clock rush hour, the less fuel one will waste.

It's funny you say that... Considering that the savings of driving as fast as possible through traffic saves you 4% on time. That is, over a 15 minutes driving like a "granny" you'd save 36 seconds.

You're not old enough to remember the gas crunch (nor am I) - but there was a reason "Drive 55" was a slogan around the nation.

[Outlander]

Not the please for arguing from what I see, so I'll just say, look up the fuel consumption figures for a jet engine. Then compare those to a piston prop engine. You will find that the piston engines fuel consumption is much lower. It is a fact. Sorry. Is there a forum where this can be discussed? In cars, gearing determines at which speed is best to travel. On any automobile with say a final ratio of 1.0 with a 2.41:1 gear for example, of course 55 is going to be more economical to drive at. But if you drive anything made in the late 80's or after you have what is called an "Overdrive transmission" meaning you have a lower than 1.0 final ratio in the tranny. Like on my stang for example, 0.73:1 with a 2.73:1 ring and pinion. You said it yourself "the gas crunch" 70's 3 speed crappy fuel economy automobiles. I have been dealing with cars for about 7 years now and am ASE certified. I would be more than happy to discuss this peacefully in a forum.

[trebuchet03]

Not the please for arguing from what I see, so I'll just say, look up the fuel consumption figures for a jet engine. Then compare those to a piston prop engine. You will find that the piston engines fuel consumption is much lower. It is a fact. Sorry. Is there a forum where this can be discussed?

Please stick to one piece of information -- fuel consumption, or efficiency. These are two VERY different things. Efficiency is defined as a ratio between useful work per quantity of energy. Fuel consumption is much less robust - units of fuel per hour etc. Look up how much power (thrust * velocity) a turbine engine can produce compared to a piston prop engine then compare the power specific fuel consumption. It's well known that a turbine engine puts out more power per pound of fuel compared to a piston prop engine (both at their respective cruising speeds).

In cars, gearing determines at which speed is best to travel.

I'm not disputing that this is a factor... The issue I'm having is that you're claiming that aerodynamics plays no role in vehicle performance. In fact, aerodynamic resistance increases with the cube of the velocity. So if you have, for example, 50 pounds of resistance at 25mph - you'll have nearly 400 pounds of resistance at 50mph and nearly 1,097 pounds of resistance at 70mph. Can you see why it's auto manufacturers spend a lot of time, resources and money on computational fluid dynamic analysis.

If you really wanted to find a more empirical number for viscous drag forces here's the equation you'd plug into:

F=-.5*rho*v*v*A*Cd
where:
F=force
rho=fluid density
v=velocity -->speed
A=frontal area
Cd=coefficient of drag

Now note, for a given object (car), everything remains constant - EXCEPT velocity. The only exception would be if your car's fairing moved around dynamically.

So, if you're willing to say that 1000 pounds of additional resistance won't put additional load on an otto engine. I think I'm assuming too much and am more than happy to begin explaining at an earlier point ;)

I have been dealing with cars for about 7 years now and am ASE certified.

Hey now, I didn't go flashing my school background or how many years I've been wrenching... But I'll give you a hint - here's some of the classes I've taken.... Thermodynamics, Fluid Dynamic Analysis, Modeling Methods.... But meh...

[IfWeChoose]

 Nice! I'm taking those classes next semester!