[Canadian Prius]

This thread was started as an offshoot of the topic 'Regenerative Braking': http://www.priusonline.com/viewtopic.php?t=2252. I decided to give it its own home here.

To a lot of people, owning the Prius is about using energy wisely. A person might have bought the car because it is energy efficient, and to save money in gas. But it soon becomes clear that how you drive the car also has a big effect on its efficiency. Knowing that, it is easy to see that this applies to any car, not just the Prius.

This can put the Prius owner at odds with other drivers. Many car owners use their vehicles as much as an expression of personal identity as a tool for transportation. Unfortunately, a common part of this is the expression of personal power and dominance. This aspect of the auto has been heavily promoted in advertising. Those big SUVs may have a practical use, but most of them never see a gravel road, so it is clear their purchase wasn't a decision based on practicalities.

However this use of the auto to express power has a real and negative effect on all of us. You could compare it to smoking tobacco. It may be a personal choice, but it also affects the air people nearby are breathing. Those overpowered vehicles are using resources and polluting the environment in a way that seriously affects everyone, so it’s not only a personal choice. Those choices affect all of us.

The smoking analogy is a good one. A non-smoker used to have to endure all the bad air and the nasty smells, even in his own house, because of the overwhelming social pressure, coincidentally also heavily promoted by the advertising industry. But now things have changed. Laws have been passed, in Canada at least, to control advertising. Society isn't so ready to accommodate unrestricted behaviour concerning smoking these days. I think the same will happen with unwise driving habits.

For most Prius owners, it isn't cool to jam your foot down on the accelerator, and burn a few months life off the tires to show a slowpoke how he should improve his driving style. What is cool is using the energy you just reclaimed coming down that last hill to take you silently another mile down the road. As hybrids become more common, this will be cool to a lot more drivers. Just like the harmful behaviour of smokers isn't tolerated as much now as when everyone did it, I think that the frivolous expenditure of energy won't be tolerated so much either. More drivers will begin to learn that using tailgating pressure to hurry someone toward a red light will be seen for the actual aggression it is, and won't be accommodated.

I see on this forum that Prius owners are conflicted between driving the way they feel most comfortable and being pressured to drive more like the old way, as if fossil fuels are unlimited and harmless.

I’m not advocating that Prius owners should take it on themselves to teach the world the right way to live. However, I also don’t think that they should ignore the good things they are learning from their excellent decision to buy a Prius. So my conclusion is, don't try to send messages, just drive smart. The rest of the world will catch on eventually

 

[kjb516]

For most Prius owners, it isn't cool to jam your foot down on the accelerator, and burn a few months life off the tires to show a slowpoke how he should improve his driving style.

With VSC installed in my Prius, I don't believe I could do this even if I tried.

 

[swepri]

I think it is a matter of culture. In Sweden a fairly new buzz word is ECO-driving. This involves many of the driving techniqes discussed on Prius forums. Brisk acceleration, shift to a high gear as soon as possible, use engine braking instead of brake pedal, try to avoid stopping and so on.

Since gas prices have been very high here (due to taxes) for many years, I believe that Swedish drivers already has adopted a more efficient driving style. As I understand it the gas price in the U.S. has been very low until recently so this has not been an issue before (except for the odd tree-hugger).

In my case, I traded in a Camry for the Prius. I intend to drive the Prius just the same way, because I already used an effective driving style. So far the Prius has about half the consumption of the Camry (or double mileage ). I'm happy with that. I don't think that I will stop using the AC to squeeze out a mile more between tank stops. I use the Cruise Control whenever safe to do so instead of actively try to coast or stealth or whatever.

The Prius itself has a very good mileage so I feel that trying to maximize mileage at any cost is not necessary or safe, drawing attention from the world outside the MFD.

That is my 2 cents...

/Paj

 

[CaPriusLover]

When I first got my Prius, my goal was to get to driving speed without using the ICE. I quickly discovered that people did not like this. Fortunately, I found this site and read a few places that it is actually better to get to speed quickly and then let the electric motor maintain that speed. That certainly made it easier on me as I was no longer pissing off the driver behind me!

But I still refuse to go much over the speed limit. Most highways here have a speed limit of 65MPG. I set my CC to 67 and drive in the center lane. I know this pisses some folks off, and I will get out of the way if it makes sense for me to do so. Keeping my top speed lower than what I use to do (85MPG +) is something that quickly became a habbit. And get this, driving is a lot LESS stressful now! The extent of the stress I feel is when someone infront of me causes me to hit the break too hard!!

I have seen a few Prius owners who drive their car like they would a Corvette, and I just can't figure that out!

 

[AgentElrond]

Too bad phpBB doesn't allow "multiple choice". I *will* start coasting if I have to stop, even if someone else is behind me (hey, they'll have to stop, too), but not "excessively"; i.e. I'm NOT going to coast from 45 down to 25- if I'm a half mile or more away from the intersection.

The Energy display will show whether any power is going to/from the wheels. If it's effectively "blank", there's no engine braking going on atm, and the LRR tires allow you to pick up some "free" distance (even if it's just a little).

 

[CaPriusLover]

I *will* start coasting if I have to stop, even if someone else is behind me (hey, they'll have to stop, too), but not "excessively"; i.e. I'm NOT going to coast from 45 down to 25- if I'm a half mile or more away from the intersection.

I do that too. Especially if I'm exiting the freeway. There is a HUGE amount of room to regen the battrey and up the average MPG!!

 

[ehurtley]

I think it is a matter of culture. In Sweden a fairly new buzz word is ECO-driving. This involves many of the driving techniqes discussed on Prius forums. Brisk acceleration, shift to a high gear as soon as possible, use engine braking instead of brake pedal, try to avoid stopping and so on.

Some of those are old wives tales. Shifting into a higher gear as soon as possible does *NOT* increase efficiency. An engine is most efficient closer to its maximum RPMs than its minimum. I read a study performed for truckers (whose trucks have more gears, so it's more imperative for them, where changing shifting style can increase by even one mpg, which is HUGE,) that proved that 'early shifting' is worse. The whole point of the Prius' variable transmission is to maximize engine power, and it does this by INCREASING RPMs when appropriate, even when all that power isn't really needed, just because the engine will be more efficient.

Second, engine braking in a normal car does use more gas than coasting. It saves wear on the brakes, but it does use more gas. Avoiding stopping is the big one. If you can hold your speed steady, rather than accelerating and decelerating, that will increase mileage by a LOT. A good example is in very bad traffic, when traffic slows to 10 mph, then speeds up to 30, then slows to 10, then speeds to 30, etc. It is better if you just go a constant 20, letting the car in front of you go far away, then near, then far, etc. When you're going the constant speed, rather than 'ricocheting', you save energy by maintaining your kinetic energy, rather than throwing it away as heat (in the brakes or the engine,) and then you don't have to expend that energy again to re-accelerate. (Not to mention that by doing this, you cause the cars behind you to maintain constant speed, which helps alleviate the whole 'stop and go' phenomenon. Two cars next to each other, going constant speed behind 'stop and go' traffic, can make all the traffic behind less annoyed by getting rid of the 'stop and go'. Just make sure that you are averaging the same speed as the stop and go. Otherwise, you'll piss off everyone behind you.)

 

[Canadian Prius]

A good example is in very bad traffic, when traffic slows to 10 mph, then speeds up to 30, then slows to 10, then speeds to 30, etc. It is better if you just go a constant 20, letting the car in front of you go far away, then near, then far, etc.

What you say here makes a lot of sense. When you do this, you will be saving fuel in your car, and you conceiveably could be saving the same amount of fuel for each of the two hundred cars behind you, which would really add up.

I have noticed, though, that if any space opens up in front of a driver in any traffic jam, not only does he seem to feel compelled to close it up right away, but he seems to expect the same of the car ahead of him. So your response is pretty relevant to the original question: when we change our driving patterns in favour of efficiency, but at varience to the established patterns, are we showing bad manners? i.e., if the driver behind you becomes annoyed only because he perceives he is being inconvenienced, but in fact is not, is that a bad move on your part?

 

[ddc]

Shifting into a higher gear as soon as possible does *NOT* increase efficiency. An engine is most efficient closer to its maximum RPMs than its minimum.

For an Otto cycle engine, this is not true. It generates its maximum power at high RPM, but not maximum efficiency, because of pumping loss. At high RPM, you have to move a lot of air through the engine. The BSFC curve shows maximum efficiency at low RPM with a wide throttle plate opening. Therefore, there is some benefit by shifting earlier. This is what the "economy" setting on an automatic transmission does, and why 5 and 6 speed transmissions increase mileage. However, I don't know about the 2004 Prius engine. Since its valves stay open longer, it may be more efficient at higher RPM. I'm sure Toyota's engineers know what they are doing, and they have the engine run pretty fast.

 

[swepri]

ehurtley: "Second, engine braking in a normal car does use more gas than coasting. "

Actually, with modern fuel injection, engine braking does not use any gas at all. Coasting with the engine in idle does. With fuel injection the gas is shut off completely until the rpm goes down to about 1000-1100 rpm while engine braking. All of the above is only useful if you need to decrease your speed of course.

Try any car (manual shift) with a trip/fuel computer and you will see this clearly. Except for the Prius of course, it works in mysterious ways :lol:

The ECO-driving style is considered to increase mileage up to about 15% for a normal car.

/Paj

 

[Canadian Prius]

The ECO-driving style is considered to increase mileage up to about 15% for a normal car.

This seems to be common in Europe, but apparently not so much in North America.

I like that they call it 'ECO-driving' instead of 'Econo-driving'. The name implies that our over-all interests are in a clean environment rather than saving a few dollars in gas money. It also suggests that the environmental aspect is more likely to win converts than the economic aspect. I'm optimistic that this is true.

ECO-DRIVING trainings lead to consumption reduction up to 20% directly after training and about 5% in the long run. The European Climate Change Programme calculated a reduction potential of ECO-DRIVING of at least 50 million tons of CO2-emissions in Europe by 2010, saving about 20 billion EUROS.

It's interesting that 20% savings is possible. It seems that the improved driving habits fall off over time to only 5%. Better than nothing.

The main points of ECO-driving are listed as:

An anticipating driving style
Maintaining a steady speed
Less speeding
Less overtaking
Less stress/aggressiveness

 

[Daniel]

I drive about the same in my Prius as I did in my Civic. The only difference is that if the SOC goes up to 6 bars or more, I try to use golf-cart mode. If for any reason it is reluctant, I engage EV mode until it's back down to 4 or 5 bars. Obviously, I could not do this in the Civic.

Conservative driving habits use less gas in any car. I'm not sure why driving the Prius would make me drive more conservatively than I did in the Civic. I save more gas by driving so few miles, than the most conservative driver who puts on more miles.