ECO vs Normal vs PWR Mode - really just accelerator mapping?

As I understand it, there is no difference whatsoever between any of the modes, except in the amount of pedal pressure required to depress the accelerator a given amount...

 

Eco mode throttles back on climate control. Other than that, the modes differ only through "throttle" mapping. At least that's how the Prius Chief Engineer explained it to us in Detroit.

Tom

 

For what I understand from previous posts, the 3 modes selection comes from concern for safety vs practical attainability in getting good FE based on average driver behavior.

Imagine one need to search for power-mode in the even of urgent overtaking or need for sudden power requirement.

The system will allow you to override the ECO mode with a simple near-WOT input on the accelerator.

And yes, I suspect one can still get good FE with driven correctly regardless in which mode one is in.

That principle of economical-sensible driving behavior applies to normal gasoline vehicles too.

 

Its about fine motor control. Maybe you have it but other may not. Or other people don't want to spend one week adjusting to a car.

Why is the speeddial in a car so big - everyone can read? Why are there indicators about which gear (D, R, N etc) you are in - you shifted it didn't you? A reminder that the parking brake is set? You can feel it with your foot, no? If we can all type, why are letters printed on the keyboard?

It is ergonomics - to make it easy for all people.

 

It's about fine motor control, and also about marketing. Having the three modes is fairly cheap and easy to do, and they add a certain gee whiz aspect. They also change the perceived peppiness of the car. Honda figured this out years ago: If you map most of the throttle response to the first bit of accelerator travel, it makes the car feel very powerful. When you drive a Honda Accord, you press the gas just a bit and the wheels spin. It makes it touchy to drive, but people like the feel. It doesn't make it any more powerful, but it feels more powerful.

The three modes let the Prius fit the expectations of a variety of owners. Those that are serious about mileage will like Eco. Those wanting something sporty will enjoy Power. The rest of us can drive around in Normal and do just fine.

Tom

 

Here is my question, since all the buttons do is change the mapping of the accelerator pedal, why can we not get the eco indicator to come on in power mode.

The HSI is in the same spot in normal, press power mode button and leave the HSI in same position and eco indicator goes out.

Brake and go into CHG in HSI and the eco indicator does not come on in power mode. Have the instant MPG meter at 100 MPG, still no eco light????

Did they just disable the ECO light in power mode even though you are getting the same gas mileage as in other modes when the ECO light is on?

 

The ECO light, like all indicators in the Prius, is driven by software. Someone made a decision to not use it in power mode. I suspect it is a deliberate attempt to move drivers away from power mode if they are interested in economy. Much of the success of the Prius comes from modifying the behavior of the driver with feedback.

Tom

 

Kinda what I figured. Funny thing is, I find my eonomoy is often a little better in power mode than in normal. I think it is also a human behavior thing. I think when I drive, pulling away from a stop, I natuarally like a little pick up, so in non power modes I ened up pushing the accelerator much farther wearas in power mode, I get immediate response so I end up acctually using less HP!!!

Funny how that works both ways

 

What really happens is that you accelerate harder in power mode. Contrary to what many Prius drivers think, accelerating like a granny does not give you the best mileage. Unless you are going to stop right away, brisk acceleration is the most efficient way to get up to speed. In ECO mode you are less likely to use brisk acceleration, so it works against you a bit in this mode, unless you truly understand what you are doing and give it some gas.

Tom

 

I came from a Doge Charger RT (340 HP) to a prius just 2 months ago.....all I am doing is driving and hoping the car knows what to do.......I am still very much a prius idiot

 

Generally that works very well. Many people over-think the entire process. Just get in it and drive. There is plenty of time to refine your technique later if and when you are interested and know more.

Tom

 

I'm a big fan of PWR mode and use it a lot. Wish the car would stay in PWR mode. I seem to get equal or better mileage using it too...

 

Been driving mine almost a month, almost exclusively in normal mode. When I accelerate, I keep the HSI against the right edge of the Hybrid Economy area, trying not to go into the PWR area. Typical accelerations are from a stop light up to 45 MPH. Would I get better economy if I accelerated in the PWR area? That seems counterintuitive.

 

As I understand it, this is less true for the Gen III as the engine is efficient over a larger spectrum.

Using the HSI, I would define "brisk" as an acceleration on the edge of the ECO zone, without going into the PWR zone.

 

This could very well be true. The key is to keep the ICE out of inefficient zones, and to avoid using the battery.

Tom

 

If I try to stay within the ECO zone in Normal mode, I would not call this "brisk" acceleration IMO. I have to go in to the PWR zone in order to accelerate at a comfortable level to me and to keep up with existing traffic.

I find that I get better mpg by accelerating in the PWR zone and then coasting or gliding as much as possible. The quicker I get up to speed without really pushing it, the quicker I can get in to coasting or gliding modes.

 

I think the most efficient acceleration is actually a curve - stronger at low speeds (to push RPM into the most efficient range), and weaker at higher speeds (to keep RPM from exceeding the most efficient range).

Remember the pseudo-CVT that we're dealing with - at low speeds, you don't need much RPM to deliver the necessary power, so you have to "overshoot" to get into the most efficient band. At higher speeds (above 50), you're already using some RPM just to maintain speed, so you don't want to push too hard or the RPM's will quickly go beyond the green zone.

PWR mode is probably good because it induces the correct behavior at lower speeds. ECO is likely better for inducing the correct behavior at higher speeds.