Prius - Awesome !

congrats and welcome! i still get a thrill after 12 years. all the best!

 

Welcome! Glad you're enjoying the car!

After the early fascination wears off, you don't have to stay too focused on keeping the engine off. It turns out that you don't optimize your mileage by maximizing your use of battery power.

The reason is, there isn't any juice in the battery that didn't get there ultimately by burning gas. (But wait, you say, didn't some get there by regeneration when going downhill or braking? Yes, but gas was burned to get you up that hill, or to the speed you were braking from. At the end of the day, unless you bought a plug-in version, the fuel filler neck is the only place energy ever goes into the car.)

The battery is really there because it's better to re-use some of that downhill/braking energy than to lose all of it, as a non-hybrid does. But only some can get re-used, because the battery's less than 100% efficient both charging and discharging; you're paying Maxwell twice.

The consumption display and bargraph has always (back to Gen 1) been a little misleading because it shows you at 'off the scale' MPG whenever you're not burning gas—it doesn't show how much gas will be used to pay the piper for that when the engine runs next, but in the long run it's more than getting the power straight from the engine in the first place.

It would be an interesting puzzle to come up with a smarter way for the consumption display to work. It could do the math to show the equivalent MPG when running off the battery—but to avoid double-counting, it would also have to increase the MPG displayed when the engine is running and charge is entering the battery. I don't think it's a problem with any one right answer: some arbitrary choices would have to be made (just like the current behavior to show electric running as off-scale MPG is an arbitrary choice), but there might be other ways of making those choices that would give you a more realistic sense of when you're driving most efficiently.

-Chap

 

Maybe they could have a second meter showing how much energy is being used out of the battery (miles per watt or something). Have it right next to the MPG one and scaled so that when the bars are the same height it would have been the same MPG for the car to move it with the gas engine. But I don't know if cars know how to measure electric efficiency - do any of the EVs have any kind of efficiency display or is it always just miles remaining?

 

You wouldn't be the first person to be tripped up by that.

Sometimes you can manage to go down a hill without using energy at all (gasoline or electric). You can watch the arrows on the display. If there are really no arrows at all, or only arrows into the battery, you're doing great.

However, sometimes, even just to maintain speed on a gentle downhill, you will see arrows from the battery to the wheels. Most of the time that isn't free, because the car's computer wants to keep the battery charge in a tight band around 60%, and any that you spend is going to be paid back later, with gas. Repaying the battery with gas later is less efficient than just using the gas to move the car now, because the battery has charge and discharge losses.

In some exceptional cases, using charge from the battery is closer to free, for example, at the end of a very long downhill if the battery state of charge is now well over 60%. The car will be happy to use up that excess charge (back down to 60%) without insisting on making it up later.

Right, the next good question is, what energy are you recapturing as you come to that stop sign? The answer is, you're recapturing the kinetic energy of the car moving at speed. Where did that energy originally come from to bring the car up to that speed? It came from burning gas. Or rolling down a hill. If it came from rolling down a hill, gas had been burned to take the car up that hill. You could maybe count one "free" downhill when you first bought the car, if the dealer was up top a big hill. After that, you get no free lunches.

Your only sources for energy to move the car are the gas engine, or energy from the battery. Neither is free. If you bought a plug-in, you have two ways to get energy back into the battery, but if it's a plain non-plugin Prius, you have only one way to ever put energy back in the battery: filling the gas tank. Energy goes from gasoline to battery in one of several ways: directly (any time the ICE is making more power than the car needs at the moment), or by driving the car to higher speeds or elevations and then reclaiming the energy when returning to lower speeds or elevations.

All those ways of turning gasoline energy into battery charge are less efficient than just using the gasoline to move the car in the first place. They are, however, more efficient than just throwing energy away from stops and downhills (as non-hybrids do). And they allow the car to use a more efficient engine with lower peak power than if there were no battery. That's where you're really winning.

-Chap

 

I would leave it in D virtually all the time. If you're going downhill and feeling a bit too much regen drag, just touch the gas slightly, that'll dissipate it. If you're coming down a mountain, then it's a good strategy to shift to B, which reduces charging and uses the engine compression to slow the car some.

The only time I use Neutral is if I'm parking on a hill with curb, want to gently roll the tire into the curb. Never use it while driving.

 

Does your "one" have a physical key? That would be almost a plus, considering the lost fob horror stories. Interesting site with Prius info:

Toyota Prius’s confusing Trim levels I, II, III, IV and V | Diminished Value Car Appraisal

 

Nothing wrong with using Neutral! I do so on occasion, As long as you stay in control and pay attention to keeping your battery above half. I tend to use it and then flick it into gear and get some regen if if looks like a stop or slow down is imminent ahead..

Neutral tends to speed you up a little and use no gas obviously and in my Gen 4 anyways if I were to leave it in gear it tends to try to regen maybe a 1/5th of the regen bar thus slowing you down ever so slightly. Neutral has its pluses and is useful in certain situations!

I think of it this way, if there is a downhill that is long and steep enough (like a rolling hill that you could safely glide down and over or a long straight open downhill) plus my battery is charged enough to not worry about trying to top it off why not flick it over to Neutral. Remember safety first though, don't do this in the Rockies!! Lol.

Yeah, you could also feather the pedal and put the car into Glide mode but I guess neutral is kinda an easier lazy way

 

Come to think of it, Wayne Gerdes was using Neutral like a demon in a hypermiling demo.

Isn't a light touch on the gas just about the same though?

 

Well simply put you want to keep your battery above half or so because if not then your engine would have to run to regenerate the battery, that or you can do as I mentioned and flick the car from neutral into gear and use regenerative braking to boost up the battery if you have gone far enough with your neutral glide...

It's quite simple, use up all your battery and your engine will burn fuel one way or another to regenerate.. Hence my explanation in the last post

 

Watch the bar on the Hybrid Synergy Display. When you're coasting, foot off the gas, there'll be a slight amount of charge happening, you can see it. Step on the gas lightly, you can see that charge disappear, and you can feel the car roll more freely. Push more, you do start to use charge, propel the car electrically. But there's an easy-to-find sweet spot.

 

Yup, as we all know that's the Glide part of "pulse and glide"..feather the gas pedal in the correct spot and you hopefully shall use neither fuel nor EV...Plus this is easier done in ECO mode. FYI.

Or you can throw it in neutral and do the same thing kinda lazy like, like I mentioned a few posts above...easier done on longer downhills..