Which Driving Mode Do you use?

I must say, I really like Power mode. It reminds me a little bit of my VW TDi, but with another 10 mpg.

 

If I may, a bit of clarification about the "modes" and why and in which way they came to be, in my humble opinion, in the Prius Gen4 and Gen3.

Before I start, it has to be clear that Gen3 has less efficient power electronics and internal combustion engine (ICE) than Gen4, which results in Gen3 to have the same performance as Gen4, but with more HP necessary. And higher fuel consumption. This means that Gen4 has more leeway on what it can do with the power/electricity/torque it has at its disposal. Moreover Gen4 has automatic front grill shutters, which means the ICE can be kept warmer than in Gen3 affecting HVAC usage.

That said, in Gen3:

• EV mode: forces the car to use the battery only, within limits of speed, acceleration, ICE temperature, ambient/battery temperature and charge; with a full charge of the battery you can drive up to 1mi/2km. The only real "efficient" use IMHO: to move the car in a parking lot between places, taking the car in the driveway for a wash, or when entering a closed garage to avoid stinking the place (essentially when short distances need to be traveled and you don't want the ICE to turn on at all (or anymore)). EV mode can be activated before the ICE kicks in for a warm-up cycle, by pressing the EV button as soon as the car is turned on. Considered a marketing stunt, it has instead a (very limited I admit) utility. In general car driving, just don't use it. Gas pedal response, within the limits of EV mode usage mentioned above, mimics the mode you are in (ECO/Normal/PWR). HVAC is always off in EV mode.
• ECO mode: the response of the accelerator is less than linear, the selected temperature of the cabin in winter is kept by having the fan blowing fresher air, but at a lower speed (reducing "wind-chill"), thus allowing to keep the ICE OFF at traffic lights more often than in Normal Mode - very helpful in winter. There is a non confirmed speculation (coming from a Lexus CT 200h (which shares the same exact drivetrain as the Prius Gen3) press release, that changing the modes, would enable different voltages to the electric motor) that the voltage to the motor is limited to 500V rather than 650V in a wider range of gas pedal positions, thus reducing battery usage at the expense of electric motor performance. I never saw real data about it. ECO mode is essentially there to teach drivers to go light with their acceleration and to reduce fuel consumption in winter.
• Normal mode: the gas pedal response is linear. All systems are working at nominal levels.
• PWR mode: the gas pedal response is more than linear, HVAC works normally, the gas engine tends to stay on longer than usual especially when braking/coasting to make sure the battery is well charged to allow for a better response when accelerating again; PWR mode is reset to Normal when restarting the car.

In all modes above (excluding of course EV mode), the car has always access to the full power of the drive train (i.e. 0-100km/h//60mph is the same regardless of the mode). You floor it in any mode, the response is the same.

In Gen4:

• EV mode: same function as in Gen3, but 20% more range (as the battery is 20% bigger and more efficient), and HVAC will run if possible (ICE engine still warm or external temperature allows it).
• ECO mode: the gas pedal response is the same as Normal mode of Gen3 (yes!); at least on the EU version you can select whatever HVAC mode you want (eco/normal/fast); no other known changes to compared to Gen3 and Normal mode in Gen4
• Normal mode: gas pedal response is more than linear (and not strictly linear!), HVAC can be set to eco
• PWR mode: gas pedal response way more than linear (more than Normal mode), engine braking is stronger than in other modes, the gyroscopes of the car are used to detect the driving pattern (e.g. winding roads) to enable better engine torque response (i.e. prepare the power train for an upcoming turn and getting out of it quickly/responsively), HVAC can be set in any mode (eco/normal/fast).

So, in Gen3 the modes tried to improve fuel consumption or performance, and it is not just a "gas pedal mapping". While in Gen4 it seems that the modes are more concerned with driving style than anything else.

I was always driving in Gen3 in Eco mode because I wanted the HVAC in eco mode, especially in winter, and I could better tune the gas pedal to control when the ICE would turn off in coasting. I would get consistently better MPGs in ECO than in Normal mode.
In Gen4 instead I am driving in Normal mode the whole time, because I can set the HVAC to Eco regardless, and I get an extra kick when accelerating from a stop (thanks to the extra 20% performance from the electric drivetrain) and since the hybrid drive train is not so finicky on when it will shut down the ICE (I can glide and even accelerate moderately electrically up to 90-100km/h!), I don't need to fine tune my feet pressure that much any more.
Moreover, one can in city traffic reach a decent speed electrically without necessarily disturbing the driver behind you or pressing just enough to get above the mid-line and get great MPGs. In Gen3 you had to fill the HSI bar and driving like a granny or trying to stay withing the lower half of the HSI resulted, at least in my case, in lower MPGs.
Also, I have been a Gen3 driver for 7 years, which means my foot is more accustomed to the way the hybrid drive train works, so maybe I don't see huge if any MPG changes, between ECO and Normal mode in Gen4.

That all being said, based on how you drive and how you accelerate, each mode might in fact yield you better mpg. Some using PWR mode might surely get better mpg, because they tend to get to cruising speed quickly and fast enough to avoid any further acceleration, and then glide electrically sooner than they would do with ECO mode, where they would feel compelled to press the pedal even more to obtain the same acceleration, as they are used to feel from ECO mode a quite "lame" response the whole time.
Essentially the effect on MPG is mostly from how one accelerates and how the modes will affect each personal's acceleration pattern.
But modes are not just "gas pedal response", as I explain above, so if the gas pedal were used the same way in all the modes, MPGs could probably be different, especially in Gen3.
I think Gen4 has so much leeway in what it can do with the power electronics and engine, that the differences are smaller between modes (assuming acceleration patters are the same) than what could be seen in Gen3 using different modes.
I never use PWR mode in Gen4 for example, because I like a more smooth ride; in city traffic Normal mode provides me plenty of response, and I don't like the extra engine braking (I find the regular engine braking and crawl quite annoying already).
I never used PWR mode in Gen3 in city traffic because it would be too much.

PS: the modes do affect the way the DRCC keeps up to speed.

So in the end, do really use whatever mode you want, especially in Gen4, but be aware that it is not just "gas pedal response" as most are led to believe.

 

Good write up and comparison. I took off early today and had the car up to 70 on the way home and it was pretty easy to get it to run on battery once I was up to speed. Never had a Gen 3, but the Gen 4 is astoundingly efficient.

 

Great job! There's nothing more needed to say after this!

Posted via the PriusChat mobile app.

 

@pakitt Technical website question if you don't mind: how do you get those bullet points?



On topic: if ECO in the fourth gen is the same as Normal in third gen, that'd be the mode for me. Thanks for the extensive overview. My one reservation: I wonder if Toyota has fallen into the "Honda" trap, is possibly overtaxing the hybrid battery in fourth gen. The use of the battery seems to be increased phenomenally.

 

Agreed, excellent commentary by pakitt.

I am definitely not going to use the PWR mode on a wet Street, owhen it is raining. I believe that is why I spun the front wheels. Even at low speeds, there seemed to be too much torque when accelerating on a slick road.

(or it may just be that my Toyo tires do not do very well in the rain?)

 

A combination of those, and maybe you rolled over a smooth painted strip or smooth steel manhole cover?

 

Hit the Reply button, and optionally the wrench at the right side of the quick reply box if it's not showing you the BBcode, it'll show you, if you want to see how to do anything.

In any case, it's like this:

[LIST]
[*]Item 1
[*]Item 2
[*]Item 3
[/LIST]

Which produces this:

• Item 1
• Item 2
• Item 3

(Also, I used a [plain] BBcode tag to force it to not parse the BBcode for making a list.)

 

Lemme try one, from scratch:

• list one
• list two
• list three

Ok, thanks for that.

 

That is quite possible, Mendel.

I also lost traction briefly when braking from about 40 mph. Nice smooth braking… And I don't think I ran over anything. During our next rain I'm going to go out and intentionally brake a little bit harder, and see what reaction I get from the TOYO's.

(They are inflated only 4 psi over the specs.)

 

Can you hear/feel traction control kicking in at all? There'd be a flicker from the indicator light on the dash too.


You can switch it off on fourth gen too, might be a factor:

 

As I said in my other thread, is that the loud BANG I heard? (I don't usually notice those little icons on the upper dash display.)

Sorry for being off topic. I am now a Eco or Normal drive-mode man.

And I also found out that the B seems to work better when I have the car in Eco, and going down hills. (I never felt the B when I was in power mode.)

 

Are you supposed to use B in power mode, or not?

 

It doesn't mention anything about that in the owners manual. But I definitely felt more engine braking when I had the car in eco-mode.

 

I wouldn't use B for short downgrades.

 

No way man, it's all about the button.

Posted via the PriusChat mobile app.

 

I finally used B mode yesterday after going on a short morning hike in the mountains. My friend was checking out my car for the first time and asked what the B on the shift meant. I gave my very basic understanding about how it makes the engine slow down the car when going down long hills and he said, hey why don't you use it going down the mountain? Well duh!

I was already in Eco Mode and switching into B from D was immediately felt. I only used the brake when my friend's car in front of me braked slower than I was going. I think if he hadn't braked I would have mostly coasted between 30-40 mph (in a residential 25 so was good he was in front of me).

Some parts of the drive leveled out and had speed bumps (it's a gated community) so I had to use the gas to get back up to speed during those short stretches.

Do those of you who use B on long hills switch back to D when the road levels out for short periods or do you just keep it in B the whole time?

 

Yeah I do, switch back to D during level zones.

 

It's my understanding that B interjects the transmission to mechanically slow down the car. Oddly enough, when I put it in B going down a section that I frequently traverse it makes the same high pitched whining sound as when I go down that same hill using cruise control. In any case, it seems less strenuous for my mechanical components to do a little regen braking so the moving bits don't complain so profusely.

 

I almost always use ECO. I can feather the throttle more easily and it defaults the HVAC to its ECO mode, whatever that means. I bought the car to save fuel so that's the mode I use. I have use PWR a few times, but mainly it's while playing sporty driver say at the stop light drag races onto the interstate or whatever. The faster tip in on the throttle feels like I get a much better throttle response off the line. Haven't tried it on a windy road or anything to see what it does on a road course but I like that I have the option. I haven't used "normal" very much at all but I suspect I will when (if?) this winter kicks into full gear. Again it's mainly for the default setting on the HVAC that I would use it though.