How are you making so many MPGs!?!

[nullxposur]

This question is not just for Gen3 but for Gen2 as well. I have a Gen3 II and am making 40-42 mpgs. Granted, I had a 2006 Civic before and I was making 26 on the city, 36 or so on the highway.

On the Civic, I drove like a maniac on the city. On the highway, I'd range between 70, 80, or sometimes 100 when on free range. With the new Pri, I don't drive like a sh!thead, but I don't, by far, hypermile. I do slowish take offs but still get around 60-70 on the city (lots of interstate roads).

My question is, how are you all making such huge MPGs? I must say, I'm quite please that I'm not driving as bad as before but still not limiting myself and am getting 40-42. That, to me, is impressive. Still, I see others making 60+ and I must just wonder.

[patsparks]

Button off early, that's it.
For me it isn't about accelerating slowly, it's about lifting my foot off the accelerator when I know I'm coming to a red light. Avoid the brakes.
Read the MPG threads on PC for more information.

[DeadPhish]

Originally Posted by nullxposur

This question is not just for Gen3 but for Gen2 as well. I have a Gen3 II and am making 40-42 mpgs. Granted, I had a 2006 Civic before and I was making 26 on the city, 36 or so on the highway.

On the Civic, I drove like a maniac on the city. On the highway, I'd range between 70, 80, or sometimes 100 when on free range. With the new Pri, I don't drive like a sh!thead, but I don't, by far, hypermile. I do slowish take offs but still get around 60-70 on the city (lots of interstate roads).

My question is, how are you all making such huge MPGs? I must say, I'm quite please that I'm not driving as bad as before but still not limiting myself and am getting 40-42. That, to me, is impressive. Still, I see others making 60+ and I must just wonder.

DO NOT accelerate slowly from a dead stop. Just punch it and go.
Accelerate normally even quickly and get up to speed at least as fast as any other driver.....then lift off the pedal and coast / glide as much as possible.

Two other key issues:

• if you see that you are likely to have to stop up ahead anticipate and let off the pedal entirely and coast up to the stoppage;
• NEVER, EVER, EVER come to a dead stop, try to time it so that you're always rolling if possible and if safe and legal.

OK the last suggestion is probably impossible to do but the point is that coming to a dead stop at any time requires a relatively massive amount of energy to overcome the inertia of sitting still. Stop signs and stop lights back to back to back are death on fuel economy.

[yogadoc]

Originally Posted by DeadPhish

DO NOT accelerate slowly from a dead stop. Just punch it and go.
Accelerate normally even quickly and get up to speed at least as fast as any other driver.....then lift off the pedal and coast / glide as much as possible.

Two other key issues:

• if you see that you are likely to have to stop up ahead anticipate and let off the pedal entirely and coast up to the stoppage;
• NEVER, EVER, EVER come to a dead stop, try to time it so that you're always rolling if possible and if safe and legal.

OK the last suggestion is probably impossible to do but the point is that coming to a dead stop at any time requires a relatively massive amount of energy to overcome the inertia of sitting still. Stop signs and stop lights back to back to back are death on fuel economy.

1+

[bestmapman]

Drive the speed limit. That should put you at or abovr EPA rating.

[ken1784]

Following is a copy of my post.
-----
There are a lot of factors we see low mileage such as...

• break-in period - We'll need at least 2000 miles to see a normal results, especially with new tires
• short trips - We'll need an extra warming up fuel other than the driving fuel
• A/C use - We'll need an extra fuel for the A/C system energy other than the driving fuel
• hybrid driving skills - We'll see better and better mileage numbers after learning how to drive our Prius
• highway driving - Above 46 mph, the engine is always spinning, therefore we see low mileage. Also, we see stronger air drag at higher speed
• too many stop&go - The best one is non stop 25 - 35 mph driving
• steep hills - A flat or very gentle up/down hills are good
• cold weather - We'll see lower mileage on cold weather than the warm weather
• low tire pressure - We have to set the tire pressure at least recommended value, but higher is better

If you understand these, you have an opportunity to see more than 85 mpg results.
1000miles a tank

Hope this helps,
Ken@Japan

[bwilson4web]

Originally Posted by nullxposur

. . .
My question is, how are you all making such huge MPGs? . . .

Another approach is to map out the vehicle performance, to look for any "knee in the curve" and "local peaks" (either minimum or maximum.) Once the vehicle performance is known, then drive on the side that favors your price-performance ratio.

STEADY STATE CRUISE PERFORMANCE

For my ZVW30:

This chart is not complete, I still have to map the 25-50 mph region with more precision but it gives good planning numbers for cross-country driving.

HILL CLIMB STEADY SPEED

Many roads are not level so it is important to understand what speeds impact climb performance:

Now this chart also shows the impact of fuel quality. The lower curve shows that a higher octane but lower energy gasoline reduces MPG but at the peak power production range, the higher octane fuel continues to produce power. The lower octane fuel requires the engine to 'detune' to avoid knock. But at any lower power setting, the higher energy, lower octane fuel is the way to go.

The other important part is to note that higher climb speeds above 80 mph on a 6% grade requires drawing traction battery power. This is important because it puts the vehicle in a performance range that is not good for the traction battery health. The reason is charge and discharge cycles 'heat pump' the battery modules. So the greater the charge and discharge cycle, the greater the heat and more stress on the traction battery. This should be avoided if you want to achieve a long, long Prius life.

DOES THIS WORK?

When I bought my NHW11, 2003 Prius, I mapped MPG vs mph on the trip back and later, in weekly commuting:

This chart showed that staying under 70 mph, cruising at 65 mph, was a great way to cover long distances without spending a lot of fuel. Of course one also needs to keep any eye out for head and tail winds. Also, it is important not to overfill the engine oil. But there was another, unusual dip at 42 mph.

The performance dip at 42 mph corresponds to a transition point between hybrid mode, where the traction battery can power the car when the engine is not needed, and 'engine always on' mode. The data suggests that transiting this control point is less efficient than being safely below, -4-5 mph, or above, +4-5 mph. This is a guard band, a speed range to avoid.

As you might expect, I also have hill climb data:

Notice that there is a peak fuel consumption in the 65-70 mph range. This corresponds to maximum engine performance. Above this speed, the NHW11 sustains speed only by drawing power from the traction battery ... this is a bad thing. But look at 55 mph, an inflection point. It turns out that when on a cross country trip, climbing hills at 55 mph does an excellent job of converting gasoline energy into hill potential energy. This also, by happy accident, corresponds to the climb speed of a heavy, semi-trailer truck in the climb lane ... where I follow at a distance.

By first mapping the vehicle performance, I've driven 70,000 miles with an average fuel consumption of 52.1 MPG. Best of all, my NHW11 has remained well within the design limits so the traction battery and drive train should last a very long time:


MAXIMUM DISTANCE SPEED

Although interesting, detailed modeling (thanks to Ken@Japan sharing the NHW11 drag formula) and testing, we've verified the maximum distance speed is 18-20 mph:


A chart is nice but it needs to be verified in the field:


Now there are other, obscure areas to investigate and some simple optimizations. But having a baseline makes it easier to conduct these experiments and tweak the system:

• cold weather tricks - block heater, radiator block, thermistor hack
• transaxle lubrication - using Type WS instead of Type T and more frequent changes
• engine maintenance
• tires - low rolling resistance, fully inflated, alignment, larger diameter (more of a shifting of critical speeds)

The Prius is a great engineering puzzle and continues to offer challenges not yet fully investigated. It really is a fun car to figure out.

Bob Wilson

[nullxposur]

Whoever posted that chart, it was really interesting when I saw it at the original post. It did make me think about driving the speed limit, but my switch to a hybrid is to limit changing my driving habits to that extreme. I had missed the disappointing MPGs threat. Very interesting!

As for taking off fast, I noticed the harder I was driving it, the more MPGs I was doing as opposed to when I'd use it on ECO mode. Why do you suggest fast take offs? If the engine requires the most energy to go from 0 to pickup, wouldn't it be a big loss of energy? I understand reducing the time you're stopped though.

[donee]

Hi null...,

I get good mileage by driving 53 mph on the highway, not 80. And by route selection that gets the car warmed up after a cold start quickly. Multiple long stop lights within 10 minutes of startup is a killer for mileage. Especially, if imediately after those lights your taking that cold engine out on an interstate highway.

Accelleration rate is tricky. Some kinda instrument is needed to do it right. Possibly the "ECO" monitor in the Gen III Prius is that thing. Super slow accelleration only works well in instances where the goal is not to get going too fast as your just going to be stopping ahead. But, if you have enough clear road ahead to coast down to 15 mph, before the light goes green, an optimum accelleration rate will help a bunch.

[DaveinOlyWA]

driving techniques and conditions are a make it break it situation. you might only be able to improve slightly from the 40-42 mpg you are getting now, then again, you might be able to get an extra 10 mpg by only implementing a few driving habit changes.

my SPM, when i drove it, i averaged just under 55 mpg. in Nov 2007, i got my Zenn so SO became primary driver. this dropped the overall average to 52-53 mpg, but the SPM was still the "family" car so i drove it when all three of us were together. so it did the occasional long trip out of town, etc.

now, i have the 2010. its now the family car. the SPM is basically used for commuting (RT is 11 miles) and its mileage is plummeting. the drive is short (5.5 miles one way) flat and at 35 mph in very heavy traffic. (she works during prime time 8-4.30 mon- fri). so add that, toss in much hotter than normal weather with A/C running most of the time and now her average is going to probably be around 48-49 mph (keep in mind, i could still easily do 52-53 mpg in same conditions so driving styles do make a big difference)

so use the advice given in the previous posts, they are all ways to inch your mileage up. the biggest thing to remember is keeping your momentum. changing speeds is what hurts you. if you get on the freeway and set cruise control for 65 mph and never have to adjust, you will improve your mileage. PERIOD. but the key is, on the freeway, you are going too fast to put your foot on the brake and the reason is, you cant have your foot on the brake and the gas at the same time. if you want to improve your freeway mileage, NEVER TAKE YOUR FOOT OFF THE GAS. doing so simply is too much of a change in momentum (now keep in mind, to avoid a huge increase in insurance rates, it may be necessary occasionally...but the less you do it, the better your mileage will be)

now, if you get on the freeway, get the attitude that no one is going to squeeze in between you and the car in front of you, your mileage will not improve (this attitude, btw, might get you to work, 2 minutes sooner) remember, EVERY TIME, you touch your brakes , and it does not matter whether you touch them hard enough to slow down, you are hurting your mileage. sounds weird huh?? try it some time... set your CC, and use the adjustment on the stalk to control your speed. it will change your set speed my 1 mph. if you can manage to not hit anyone or disengage CC (because you are about to hit someone) that only means you have learned to anticipate traffic conditions since you (like most people) will most likely not be able to maintain a constant speed on the freeway due to traffic.

also, while in town, try this. start tracking how many times your foot touches the brake pedal. track this stat for a week. then try to reduce those touches. when i am on a 4 lane road (i try to take these as much as possible unless there is a less traveled back road i can take to my destination) always be timing the light ahead as early as possible. if you see a red light and 5 or more cars already sitting there, then start to coast. normally you would only spend less time waiting at a standstill, but you were able to regen more charge to the battery which does benefit you in a SMALL way (read this to mean that you dont want to do this on purpose...only do it because you have to).

but occasionally, what will happen is the light will turn green, the cars will move out just in time for you to come coasting up, now you never came to a stop, never touched your brake pedal...what is the result?? on your trip, you probably increased your mpg for that trip 1-3 mpg depending on the length of the trip...probably increased your total tank mpg by a single tenth...not much i agree, but my tanks take me 2+weeks to burn off....

that means how many chances to perform a perfect light timing in heavy traffic???

now remember, only do this if there are multiple lanes of travel in each direction. by doing this, you will have people go flying around you just to cut back in front of you to slam on their brakes to avoid hitting the cars stopped at the light.

as a GREAT source of entertainment, track these people. in 5 minutes, see how much time they have gained by wasting their gas jockeying for position. after i had done this several times only to see the same vehicle 3 cars ahead 5 lights later... this only reinforced by goal to drive all the way across town without touching my brakes once