EV mode at every stop

No, I looked at the percentage SOC loss associated with EV take off up to different speeds and concluded that 25mph may be too high to use for every occassion. Can you please explain how you think you can make up the lost SOC without conversion losses created a negative balance?

I am not rejecting anything from Toyota but if I drove it exactly as they designed it then I would be getting lower mpg than I am currently. So assuming that a manufacture always builds something in the best way possible to achieve a specific goal YOU have is folly. Have you ever modified a car before?

LOL I achieve MUCH higher than 60mpg when I am hypermiling. When you can top something like this then we can talk. Until then you should spend more the listening.

 

None of our observations are controlled experiments. Conditions are never the same and it all depends on human behavior motivated by our personal bias.

You had commented earlier that the 18 mph cut off you used was based on a Prius hyper miler hobbyist and that even he noted that the 18 mph was just a best guess. On the other side we have Toyota who engineered the EV control and programmed the car to shut it off at 25 mph along with a lot of other parameters that control EV use. I'd say those of us who use it as engineered likely have better claim to doing it right. At the end of the day your 18 mph and my 25 mph likely have little difference between them . On the other you, me and Toyota all agree that it should be used and will increase mpg.

Dude! You are driving around in a 100 deg plus car. That 's not hypermiling, that's Carlos Castenada looking for Don Juan, flying lizards and Peyote buttons.

I'm a happy (and comfortably cool) camper with my AC on getting 54-56 mpg using EV mode to the max.

 

You are making assumptions about Toyota's intended purpose of EV Mode. Toyota's chief energizer never made any such comments to us regarding the use of EV Mode during the 2010 unveiling in Detroit.

It's usually only 96F-98F inside the car but after about 105F I admit it's a bit nutty. Around 100F+ I think it is better for the HV battery to run the AC. I sort of lost that argument and I'm not afraid to admit being wrong. I hate eating crow but if you can prove to me that Toyota intended us to use the EV Mode button up to 25mph I'll grab a fork. oh and I proposed 15mph as being a reasonable EV only take off MPH. Anything higher should be used as circumstances allow.

 

Lmao.....the banter between the two of you. Looks to me like a fork is appropriate for both of u.

 

Well put.

 

I'm reporting how EV mode works. You press it and it allows you to accelerate to 25 mph and kicks off. It only comes on when there is enough battery and other conditions that Toyota engineered into the car.

Not making any assumptions just using it as it works. You are pretty much doing the same thing only stopping short of Toyota's engineered setting of 25 mph and manually shutting it off at 18 mph. Essentially the same operation.

It sounds like an episode out of "Curb Your Enthusiasm" with Larry trapped in car with F8L crossing the Mojave Desert.

Here's a page out out of the Operators Manual for human body.

 

An appropriate metaphor considering the heat in F8L's "oven". All in good fun in my view.

 

First, Wayne is much more than just a hobbyist, he is an expert. Show me where he said that number was just a guess.

Second, if you really believe that is how Toyota designed it why would they make it so you have to hit the EV button each time?

 

Same reason PWR button has to be hit each time on the other extreme of use, one full gas one no gas. It is fair to say Toyota engineered and installed the EV Mode switch to be used to put the car in...ahem...full EV mode for short distances and specific circumstances. You can really only use the EV Mode switch one way so hard to attribute some other purpose to it or, as some seem to do, attribute no purpose to it.

 

If you think it really is the best way I want some of what you are smoking. Thinking no AC is the only way to get well over 60 mpg is very wrong as well.

 

Seriously, you just can not compare EV or plug-in with normal Prius. They have energy source from the wall outlet, normal Prius gets electric energy from ICE or regen braking. If you think that electric motors/generators and charging discharging battery are 100% efficient you live in a fairytale. Even EV can not capture and use all electricity you charge it in, efficiency of EV is around 80%.

Efficiency of ICE is very load dependent and it ranges from 0% (car standing still and running) to 37% (diesel 42%). Google BSFC map and you will understand. Prius ICE is optimized to get good efficiency at very low load, but low load means 10 kW (13 HP) and this is still to high for cruising at 30 mph.

Best use of energy is to use most efficient load of ICE directly on the wheels. Because this is not possible in normal traffic conditions Toyota designed Hybrid synergy drive (HSD) to use 37 % efficient ICE together with 80% efficient electric drive for lower load demand from the driver. But you must know that EV driving (80% of 37% ICE efficiency is 30% total efficiency) WILL ALWAYS BE LESS EFFICIENT than using ICE directly for propulsion. Regen braking will capture back so little that it's not even worth mentioning. Ask EV drivers what type of driving it takes to achieve best possible mileage, with regen braking or observing traffic before you and use as little brakes as possible.

You generally believe that EV uses way way less energy than ICE it may use less but not that much.
- Doing 3.9 l/100 km (60 MPG) in Prius means that you burning 34 kWh/100 km of potential thermal energy in gasoline.
- EV uses 15 kWh/100 km of electricity this is less than ICE but not way way less.

Add distribution and production costs to above values and you will see that it all depends on the way the electricity is produced and if you get pure coal electricity your EV will use a lot more thermal energy than Prius.

 

The problem, in the context of my post, is limited energy storage that prevents you from being in continuous ICE-off mode for a long period of time. If you need to hit the EV override button frequently, because you are not familiar enough with driving in a manner that allows the computer to optimize time with EV off, then of course you will be pressing the button more often and may even prefer to have the bigger and heavier batteries present on a plug-in.

Or, you can simply use basic hybrid hypermiling techniques that are well established here and at various other enthusiast forums and websites. These allow for high fuel economy without routinely pressing the override button. The point is that it's pretty easy to keep the ICE off for extended periods of time, even at speeds higher than 25mph, without ever pressing the button. Unless you are frequently in stop and go traffic, where override can be very useful, I'd suspect that you'd get a much better increase in mpg by learning some of these techniques, rather than relying on the override button. Otherwise, I think a car like the Volt or PIP would indeed be much better suited to your driving style. As they say, your mileage may vary, of course.

 

Seriously...believe this conversation is about using EV Mode button that Toyota has on regular Prius.

 

Do yo read what you write:

There is NO PATTERN between a car that has electric source from the wall and a car that generates all of it's electricity with ICE. If there was a pattern we wouldn't have a complicated HSD, but a normal ICE on el. generator and electric motor, no complicated planetary gear set ect. If electricity from ICE would be so cheap why are you paying for electricity to el. company, when you can generate your own el. with Prius?

I wont try any further, read line by line what I have written previously, I have nothing else to say.

 

This is a good call and probably what we all need to do. This guy is no more than a troll that should not be fed. I too am done replying or responding to him in any way, at least until I see a tank of his more than 60 mpg.

 

Let me propose a possible explanation of how accelerating on EV mode up to about 15 mph maybe overall more efficient. If we just consider the round trip kinetic energy recovered from regen braking from 30 mph to a stop. (Yes in a perfect world one would coast all the way from 30 mph to a stop). Kinetic energy at 30 mph is 4 times that at 15 mph. So if I take the round trip regen efficiency at 40 to 50 % (open to correction on this) Let say it's 40%. So 40% of 168.75 kJ is 67.5 kJ. To accelerate back up to 15 mph requires 42.16 kJ. Both these calcs assume mass of 1500 kg and speeds of 15 m/s and 7.5 m/s. So one is net ahead in energy in this example which I believe would not be uncommon in a commute that has 45 mph segments with stops (either lights or stop signs). Now if your max speed between stops is 25 mph and no traffic behind you where you can take for ever to glide to a stop, then all bets are for EV mode at every stop being the optimum, but for deceleration and acceleration rates that following traffic can tolerate, I would say using EV mode at every stop up to 15 mph ? (plus or minus) may have merit when the batteries are at optimum temperatures along with the fact at speeds below 15 mph the engine may be mostly out of its optimum BSFC range.

Note to ProximalSuns, your Avatar makes you look like a smart-nice person and it doesn't win you any integrity brownie points.

 

Excellent. It is working perfectly.

Those are not much use to smart asses.

Note to briank101, Toyota may have done the calcs better than you, more information, better information, more experience and more computer power and came up with 25 mph in EV mode as the most efficient top end speed.

 

In all these assumptions, you also have to consider when the ICE is going to run to kick in to charge the energy lost while accelerating that is never recovered. Could that energy have been used more efficiently to maintain a 40mph cruising speed, keeping the ICE off for a much longer period of time? The ICE must run eventually. If you are going for ultimate fuel economy, I propose that never pressing the EV override and accelerating slowly enough to keep the ICE off without using manual override is likely to be more efficient, though also much more annoying to drivers behind you, of course. The sweet spot in between varies widely based on driver and conditions.

I managed to get about 40% above EPA with my Highlander on my last tank without using the override at all. I'm sure others have even better results with the Prius without regularly pressing the button, too. I'm still accelerating, cruising, coasting and gliding as often as possible to automatically keep the ICE off as much as possible. Maybe I could do better using EV override more, if only it was available more often in the Highlander to try, as it is in my wife's Prius.

Exactly, and most likely, they programmed all this information and experience computer that operates the hybrid system automatically, even without the typical driver routinely pressing the manual EV override. With practice, you can go from 0 to 40mph with the ICE never coming on, even without pressing that tempting button. True story! For those situations like a jammed freeway where you know there's a 1 or 2 mile crawl, then you have information the computer lacks and forcing the EV ON override may well be a big benefit.

If you're not the typical driver, perhaps you can do better with well timed use of the override button. I'd be interested to see a controlled test demonstrating this, along with all the variables that apply to your situation such that those reading can see if this might benefit their driving as well. Maybe one of the hypermiling pros has this posted somewhere already? For those benefitting with frequent use of the override and cannot accomplish the same or better results by mastering automatic operation, I'm thinking a pure EV or plug-in may be an even better option for that type of driving.

 

First the battery energy used to get to 15 mph with slow acceleration (keeping in EV area) will be similar to the battery energy used to get to 15 mph with quicker acceleration using EV mode but not quite in the HSI PWR zone. (Twice the power for half as long is about the same total energy used) I think the battery energy is used more efficiently for 0 to 15 mph acceleration portion where the engine would not be in its BSFC sweet spot where as at 40 mph cruising one can alternate between placing it in its sweet spot and gliding. If other demands require the battery shortfall to be made up, it's better that this occurs in within the BSFC mound sweetspot.

Should the max speed accelerating in the EV portion be up to 15 mph, up to 10 mph, or up to 20 mph, I don't know but I believe's Wayne Gerde's 15 mph suggestion is a good starting point. If someone say to start the ICE at 5 mph instead, I would like to see an explanation that makes sense.

Remember my objective is not the theoretical best economy on an empty road, it's the best economy during my daily 45 minute commute (without pissing off other drivers) which averages about 7 to 12 stops depending on the traffic lights with speed limits ranging from 35 to 55 mph, but mostly 40 to 45 mph speed limits and I drive about 5 mph over the limit. I manage to stealthily do a pulse and glide most of the way, mostly with the help of rolling terrain and on the flat it's a 5 mph speed variation pulse and glide with a lot of traffic anticipation and timing. If the weather is below 80 F, I can get 60 mpg which includes a cold start on the 20 mile commute without looking like a hypermiler. I'm sure I could get 80+ mpg if I did this at 3am at night with no following traffic within a 45 minute time limit. And without a time limit who knows?

 

Sounds reasonable, but I still have to wonder why Toyota doesn't then simply alter the software to better keep the Prius ICE off automatically during quicker accelerations, at least up to 15 or 18 or 25 mph or whatever point you all deem better. If this made an appreciable improvement, wouldn't they want to brag about higher fuel economy? Heck, a simple software update could improve things for current owners as well. Conspiracy?

If not Toyota, wouldn't Honda or Ford or someone use this flaw in Toyota thinking to surpass Toyota in the last decade?