CPO 05 Prius - is 50+ MPG really this easy?

That will make your fuel economy worse. Around 1/2 of the full pedal is good, or if you want to drive by numbers keep the instantaneous MPG no less than half your speed.

To answer your title: 50+ mpg is pretty easy if you start out a non-aggressive driver, anticipate red lights and coast to them, stay below 65 mph on highways, and do not have a lot of short trips in the cold. For some people those conditions are trivial, for others nigh impossible.

I am by no means an elite hypermiler, but I try to drive for fuel economy and I have pretty good conditions. I average around 65-70 mpg this time of year in suburban/city driving.

 

Lets try this mind set:

Accelerating uses lots of energy, you do not want to spend much time accelerating. The slower you accelerate, the more time you spend in a poor economy mode.

Cruising uses very little energy, you want to get to cruising speed soon, so you can spend more time cruising.

For best economy, you do not want to drain the battery even a little while accelerating, but below that, the faster you accelerate, the less time you spend in a bad mode and the more time you spend in an economical mode.

All energy in a (stock) Prius comes from gasoline, even when you are not using gas now, it has to be replenished by burning gas.

(The above opinion is my own, and does not represent the opinion of sane, responsible members of the Prius chat community)

 

Well, I should first say I did exactly what you are doing when my car was new

Keep in mind that 100% of propulsion in the Prius comes from petrol. Maybe the energy took the scenic path through the battery and stopped for a picnic on its way to the wheels, but it was still petrol at the start. So of the tenets of Prius driving, one is burn that fuel as thermodynamically efficient as possible; and second, get the mechanical energy to the wheels with as few losses en-route as possible.

Bad engine burn, lots of losses to the wheels -- bah
Good engine burn, least losses to the wheels -- perfect
In between ? Favor good engine burn over minimal path losses. This means try to use the IC engine in its 25 - 75 power range, or 30 - 60 if you are a fuel economy nut like me. Pedal to metal is 100% of power, halfway depressed is 50%, the pedal is pretty linear.

Using the energy in the battery (which you will have to replenish later, and not necessarily at a good time for the IC engine) when you could have used the IC engine efficiently with minimal path losses will net you lower MPG.

Hope this helps. Enjoy the ride, and Welcome!

 

If you're using the battery in the prius, either charging or discharging, you are not getting the best fuel economy that you can. When the battery charges during regenerative braking, you only get back out about 60% of what went in.

Having said that, having the ability to save 60% of the energy lost due to braking is still a lot lot better than loosing 100% of it to friction braking but if you can avoid braking or using the battery at all during driving, you will get your best fuel economy.

Of course you can't avoid braking, but you can minimize it by gliding as far in advance as you can of stop when you know you'll have to. The easy way to do this is put the car in neutral. No arrows will be going into or out of the battery. Of course, if you really have to stop at some point, you'll have to put the car back into drive if you want regen braking to be used instead of just friction braking. That's why it's better to glide by using throttle position rather than going into nuetral. When you want to glide up to a stop, press the accelerator pedal so no arrows are going into or out of the battery on the MFD. If you see arrows going into the battery, you don't have the accelerator pressed down far enough. If you have arrows leaving the battery, then the pedal is too far depressed.

When accelerating also try to keep arrows from going into or out of the battery. If you do it just right, you'll only have orange arrows leaving the engine and going to the wheels with no arrows going into or out of the battery. Try not to crash as you watch the MFD. It's distracting. After a while, you'll get good enough that you won't need to look any more.

If you want to get more advanced, you can pulse and glide in city and suburban areas on the slower streets. If you accelerate from say 31 MPH to 41 MPH with no arrows going into or out of the battery and then glide from 41 back down to 31 and repeat over and over, you should be able to get high 80s with some practice. I have a 2009 touring and can manage high 70's even now and my right rear toe is off by almost a degree(about to be fixed with a shim).

 

That's strange. In the past when we've had poles here of "what's your fuel economy" only a very small minority have been that low. The median value is usually about 48.

 

This topic always interests me. Perhaps it is helpful to set up a concept of a perfect drive, and then discuss techniques to approach that nirvana.

It is all about energy. We start with a certain amount of energy in a gallon (or litre) of fuel, and send some of that energy to the wheels. Each mile (km) the car moves takes an energy amount. The situation is analogous to money: We start with a certain amount in the pocket, drop some getting it out, and buy miles at a certain cost. The miles per gallon (MPG) or miles per dollar is going to be dependent on four things:

• How much of starting chemical energy becomes mechanical
• How much of that mechanical energy we waste
• Energy losses on the way to the wheels
• The energy cost per mile

Great, now a detour through the glossary. Item 1 is thermodynamic IC engine efficiency;
Item 2 is braking;
Item 3 are electric conversion losses and friction in the transmission
Item 4 varies by terrain, vehicle speed, and tyre and gear friction.

OK, now we can describe the best MPG ever in a Prus: The IC engine sends 38% of the gallon's energy content to the transaxle, where 2% of the energy is rubbed away in the gears, and 5% is lost electrically. The tyres are pumped up, the roads are dry, and we are turtle-ing along at 30 mph to avoid air friction. This scenario is good for about 120 mpg, proven by the marathon group. Wow.

Time for practical application:
Item 1 approaches 38% when the engine is used in the 25 - 75 pedal depression range typically, most always when the instant MPG is within 10-20% of the instant speed. People with scan gauges can shoot for RPM in the 1600 - 2500 range;
Item 2 means anticipatory driving: let the road slow you down if you can rather than the brakes.
Item 3 means do not try to hoard or use the battery. Leave it to Prius.
Item 4 means keep your tyres well inflated; try to combine short trips so the movement of gears and things has less friction; and SLOW DOWN. Speeds on the highway over 70 will not result in pretty MPG numbers; 65 - 70 mph will return about 50 mpg and speeds of 60 - 65 mph, about 55 mpg.

Last topic, aka "what is the big deal with using the battery?" Well first off, the driver is better off paying attention to the road for safety, and in regards to fuel economy, avoiding brakes waste is much more important than tweaking the IC. Second, you eventually pay for everything you use from the battery so don't go out of your way to incur more conversion losses. The battery is there for a power boost when needed, and the Prius uses it (very smartly I might add) to keep the IC efficient. The driver can pretty much ignore it.

There is one place the driver can game and beat the system in low speed driving, by pulse and glide, to avoid inefficient IC use and decrease IC friction. This forum has well written monographs worth reading.

The anti-climax to the Prius hypermiler comes when it is realized that the most important aspects of high MPG driving have nothing specific to the Prius in them at all: Slow down in highway driving, and minimize brake use in town/city driving. Prius takes care of 90% of the remainder. The last 10% of maximal MPG are the last to go after.

 

That is what I was thinking. I don't see many posts of sub 40mpg and the ones that I do see look more like cases of extreme driving conditions or possibly people posting for other manufactures to defame the Prius.

 

The following site is the thoughtful person's guide to the GEN-II Prius and it's peculiarities.

Sweet spot refinement

That page is a reflection on finding and using the 'sweet spot' for over five years. Hobbit is a gem.