Fuel Economy Tip List

[acdii]

Here I will post helpful tips that have been verified by others, and will be credited to the person posting it. PM me tips you have found useful and verified and I will add them here, and also the person who posted the tip so credit goes to who deserved it.

 

First one to post is the HVAC Tip from aaronj1159

 

If it's 90 degrees outside, I set it to 85 and let it cool to there. then I take it down little by little until it's to comfortable levels.

This one works quite well, verified it myself as well as a few others. It will definitely help reduce gas consumption on those hot days. You can verify by setting MyView to the energy screen that lists climate and other and watch how the power drops once it hits 85, and by the time you reach your comfort level it should remain pretty much there.

 

FYI from acdii & hybridbear - we're keeping this topic locked so that it doesn't get filled up with other comments. If you have a tip to add or an additional suggestion please PM one of us and we'll add it or unlock the topic so you can post your tips.

Edited August 5, 2013 by hybridbear
added comment about why topic is locked

[hybridbear]

One of the most important skills for safe driving and efficient driving is to be a Defensive Driver and to be aware of your surroundings.

 

My dad drove city bus in Minneapolis for most of my life growing up and he got defensive driving training twice a year. He would always share with my mom and me what things he was taught and he would apply them no only driving the city bus, but also driving a car. Now that he's pushing 70 I can tell that his reaction times have slipped but he's still an excellent driver because he pays very keen attention to what's going on around him and is almost never caught off guard by other morons on the road.

 

One example of something that he taught me to do is being aware of stop signs in residential neighborhoods. In Minneapolis the residential intersections usually have stop signs only for one of the two streets. And the streets alternate which one has a stop sign, meaning if you're continuing down the same street for various blocks you will have a stop sign every other street. Many drivers seem clueless to this though and either don't stop and yield at their stop sign because they think you'll stop too or they stop when they don't have a stop sign because they think they do have one. I've avoided many near accidents by paying attention from afar to what the stop sign situation is at the next intersection so that I can be ready for some idiot to be unaware of the traffic situation and cause problems. There are certain intersections that I know are especially bad for this and I am extra careful around those.

 

Little things like this are how I almost never get less than a 100% brake score and why our Lifetime Brake score is at 99% after 16000+ miles. I'm sure that if I were the only one driving the car my Lifetime Brake score would say 100% but when my wife drives she probably averages 96-97% for her brake scores so she pulls it down a little.

 

As far as acceleration I sometimes accelerate at 1 bar on the Empower screen, most often about 1.5-1.75 bars and sometimes 2-2.5 bars. I determine how fast to accelerate depending on the situation. If I know I won't be going far before stopping again (i.e. residential neighborhoods with lots of stop signs, driving through downtown or in heavy traffic) then I accelerate more slowly because accelerating quickly is wasteful. Typically I accelerate somewhere around 1.75 bars on the Empower screen. I find that this is a nice balance between ICE run time to charge the battery and fuel consumption. On occasion I know taking off from a certain stop sign or traffic light that I have to hurry to make the next light green. Making the next light green by accelerating quickly is more efficient than accelerating slowly and stopping again. So in those situations I'll go as high as 2.5-3 bars of acceleration. Wow! The car really moves fast when you step on the gas that hard. The acceleration coach bar gives me a bad score after that but I know that I'm smarter than the coach in those situations.

 

Sometimes my acceleration depends on battery SOC and my knowledge of the road ahead. If my SOC is low then I'll accelerate more slowly to get more seconds with the ICE on and thus more charge in the battery for cruising. If my SOC is high then I'll accelerate more quickly, but not quickly enough that the battery shows the down arrow that it's discharging because it is most efficient to keep the battery charging even more in that situation. If I know that I'll soon be going uphill I'll try to plan my acceleration to make sure that the ICE is on going uphill because that's more efficient. If I know I'll soon go downhill I accelerate more slowly and then use the downhill to gain speed. When I'm in EV mode I try to keep the power demand to 1 bar or less, if the power demand exceeds 1 bar then I step on the gas a little bit harder so that the ICE comes on and then I'll back off to the amount of acceleration I want. That way I run the electric motor under a light load where it is most efficient and the ICE under a heavy load where it is most efficient.

 

This is how I'm able to pretty consistently average 60+ MPG in city driving, even in unfavorable conditions such as rain, extreme heat & humidity with AC use or freeway trips around town. I don't do any hypermiling like Pulse & Glide or any of that stuff because that requires too much concentration and would distract me from being a safe & defensive driver. To do what I describe above I don't have to think about it, I just do it subconsciously. Driving techniques like the aforementioned ones are the things I'm trying to teach my wife so that we can have a tank at 60+ MPG instead of them being torn down to 50-55 only because of her driving averaging about 45-50 MPG only on very similar routes. That's a 10-15 MPG difference just in our driving styles because I follow the guidelines above whereas she accelerates at about 2 bars all the time regardless of the situation and isn't as aware of her surroundings.

 

Hopefully these tips will help others to get the most out of every drop of gas in their cars.

Edited August 14, 2013 by hybridbear
typos fixed & more info added

[hybridbear]

A Note About Acceleration

There is a lot of misinformation out there about accelerating up to 62 MPH in EV Mode. While the car can technically do this, this is not what it's designed to do. You should NOT accelerate up to 62 MPH in EV Mode because this is an inefficient use of your battery charge. Since all the electricity in the battery comes from burning gasoline one way or another it is best to not only maximize the efficiency of the ICE when it runs but also maximize the efficiency of the electric motor when driving in EV Mode. As I briefly explained in this thread the ICE is more efficient at higher power demands and the electric motor is most efficient at lower power demands. This means that you don't want EV Mode if the power demand exceeds a certain level on the Empower screen. I am planning to buy a ScanGauge soon and hopefully will be able to further study this with the use of the ScanGauge II.

 

My current practice is that any power demand under 1 bar on the Empower screen should be EV Mode (provided the battery SOC will allow EV Mode) and any power demand above 1 bar should be ICE mode. Acceleration is no different. When accelerating it works well to slowly depress the pedal at first but then depress it enough that the ICE kicks on around the time the power demand exceeds 1 bar on the Empower screen.

 

A Note About the Empower & Engage Screens

The Empower screen shows only the power required to move the vehicle based on how you're depressing the accelerator pedal. When the ICE is on and charging the battery you'll find that flipping to the Engage screen gives you a different result. Note that the same number of bars appear for the ICE power demand on both Empower & Engage, however, when on the Engage screen and having separate bars for ICE power and electric motor power you will note that the ICE power bar is higher. This is because the Engage screen displays the power demand placed on the ICE both to drive the car AND charge the HVB. At times it can be useful to flip to this screen while driving in order to maximize efficiency of the ICE. You'll notice that you don't see much variation in the instant fuel economy with the ICE power bar at 1.5 bars or 2 bars on the Engage combined recharge & power to wheels display. You'll also notice on the Engage screen that the power level is never less than 1 bar when charging the battery. For example if you have a very low SOC the ICE will stay on even when the Empower screen shows no power demand and your foot is not touching the accelerator. During this time the ICE is completely focused on charging the HVB and will still show 1 bar of power demand.

The only time the Engage screen will show less than 1 bar is when the car is in Stage 1a as mentioned here.

[hybridbear]

Now that I have a ScanGauge II two of the most useful gauges I've found are the Horsepower and LOD (Load) gauges. Below is a BSFC chart for the 2nd Gen Prius (1.5L engine) and 3rd (current) Gen Prius (1.8L engine). BSFC = Brake Specific Fuel Consumption. If you aren't familiar with what that means you can read more here. Do take the time to read the explanation. Understanding this concept is crucial to maximizing your fuel economy.

 

 

Notice how the Prius is most efficient, a low g/kWh, at a fairly high power (kW) output but a low engine speed (less than 3650 RPM). To get such a high power output a such a low speed the computer must be placing a high load on the engine. As described in the link above, in a normal gas car you're often operating at only about 25% throttle which is a light load on the engine. In the hybrid, the generator places a load on the ICE to increase the load and get the car to run in a more efficient BSFC region. For the Prius, which has a smaller engine, the kW output is a maximum of about 30 kW in the peak BSFC region. 30 kW = 22.37 hp. That isn't a lot of power demand.

 

Unfortunately I don't have a BSFC graph for the FFH 2.0L engine. However, based on my observations of hp and LOD readings on my ScanGauge I have a pretty good idea where it is...

 

When the FFH SGII output shows 33-42 HP (24.6-31.3) I have observed a LOD of 95+. This is typically a 2 bar acceleration on the Empower screen. The FFH acceleration coach considers this to be efficient and returns the maximum score on the acceleration coach bar. If I accelerate more slowly, I only see LOD numbers in the low seventies to low eighties. When accelerating harder than this I still see a high nineties LOD but the ICE is too far off to the right on the graph and is out of the most efficient range. This leads me to believe that the peak BSFC region for the Ford 2.0L engine is somewhere around 20-35 kW of power. I hope that soon we'll get a BSFC graph to be able to know for sure.

Edited September 9, 2013 by hybridbear

[hybridbear]

You could accelerate more slowly and use more electric motor power, but I think that is actually bad. Another SGII screen I've been watching is the amps flowing in and out of the HVB. When in EV Mode at 1 bar on the Empower screen the battery is sending about 20 amps to the electric motor. Unfortunately I cannot get a gauge that shows the torque, RPM or power output of the electric motor to be able to understand what that 20 amps does. However, it seems that any acceleration above that area quickly pulls a lot more amps. 1.5 bars pulls close to 40 amps from the battery. This is why I think that accelerating any faster than 1 bar in EV mode is too much and is better served accelerating with the ICE. Even at 1.5 bars the ICE will make about 25 hp or 18.6 kW. On the Prius engine this falls within the peak BSFC zone and it likely does for the Ford 2.0L engine too. Considering that electric motors are most efficient at lower RPM and power demands it is likely that above that 20 amps power draw the electric motor efficiency decreases. Hopefully I will hear back from Linear Logic soon with information about how to display other stats using XGauges.